|
|
| SN-38 |
|
| CHEBI:8988 |
|
| A member of the class of pyranoindolizinoquinolines that is (4S)-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14-dione bearing two additional ethyl substituents at positions 4 and 11 as well as two additional hydroxy substituents at positions 4 and 9. It is the active metabolite of irinotecan and is ~1000 times more active than irinotecan itself. |
|
This entity has been manually annotated by the ChEBI Team.
|
|
| ChemicalBook:CB5320664, eMolecules:2726126, Selleckchem:sn-38, ZINC000004099013 |
|
|
Molfile
XML
SDF
|
|
|
more structures >>
|
|
call loadScript javascripts\jsmol\core\package.js call loadScript javascripts\jsmol\core\core.z.js -- required by ClazzNode call loadScript javascripts\jsmol\J\awtjs2d\WebOutputChannel.js Jmol JavaScript applet jmolApplet0_object__709653312367053__ initializing getValue debug = null getValue logLevel = null getValue allowjavascript = null AppletRegistry.checkIn(jmolApplet0_object__709653312367053__) call loadScript javascripts\jsmol\core\corestate.z.js viewerOptions: { "name":"jmolApplet0_object","applet":true,"documentBase":"https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:8988","platform":"J.awtjs2d.Platform","fullName":"jmolApplet0_object__709653312367053__","display":"jmolApplet0_canvas2d","signedApplet":"true","appletReadyCallback":"Jmol._readyCallback","statusListener":"[J.appletjs.Jmol.MyStatusListener object]","codeBase":"https://www.ebi.ac.uk/chebi/javascripts/jsmol/","syncId":"709653312367053","bgcolor":"#000" } (C) 2012 Jmol Development Jmol Version: 13.2.7 $Date: 2013-10-01 11:35:15 -0500 (Tue, 01 Oct 2013) $ java.vendor: j2s java.version: 0.0 os.name: j2s Access: ALL memory: 0.0/0.0 processors available: 1 useCommandThread: false appletId:jmolApplet0_object (signed) starting HoverWatcher_1 getValue emulate = null defaults = "Jmol" getValue boxbgcolor = null getValue bgcolor = #000 backgroundColor = "#000" getValue ANIMFRAMECallback = null getValue APPLETREADYCallback = Jmol._readyCallback APPLETREADYCallback = "Jmol._readyCallback" getValue ATOMMOVEDCallback = null getValue CLICKCallback = null getValue ECHOCallback = null getValue ERRORCallback = null getValue EVALCallback = null getValue HOVERCallback = null getValue LOADSTRUCTCallback = null getValue MEASURECallback = null getValue MESSAGECallback = null getValue MINIMIZATIONCallback = null getValue PICKCallback = null getValue RESIZECallback = null getValue SCRIPTCallback = null getValue SYNCCallback = null getValue STRUCTUREMODIFIEDCallback = null getValue doTranslate = null language=en_US getValue popupMenu = null getValue script = null Jmol applet jmolApplet0_object__709653312367053__ ready call loadScript javascripts\jsmol\core\corescript.z.js call loadScript javascripts\jsmol\J\script\FileLoadThread.js starting QueueThread0_2 script 1 started starting HoverWatcher_3 starting HoverWatcher_4 The Resolver thinks Mol RS4 - Ideal conformer Mrv1927 05252115423D starting HoverWatcher_5 Time for openFile(RS4 - Ideal conformer Mrv1927 05252115423D 49 53 0 0 0 0 999 V2000 -1.8210 1.1160 0.1240 C 0 0 0 0 0 0 0 0 0 0 0 0 -1.1310 -0.1070 0.1020 C 0 0 0 0 0 0 0 0 0 0 0 0 -3.9320 2.4470 0.1690 C 0 0 1 0 0 0 0 0 0 0 0 0 -4.2000 2.9150 -1.2620 C 0 0 0 0 0 0 0 0 0 0 0 0 -0.7790 2.2050 0.1330 C 0 0 1 0 0 0 0 0 0 0 0 0 0.3220 0.1820 0.0910 C 0 0 0 0 0 0 0 0 0 0 0 0 -3.1200 -1.2960 0.1050 C 0 0 0 0 0 0 0 0 0 0 0 0 1.4020 -0.6750 0.0680 C 0 0 0 0 0 0 0 0 0 0 0 0 -3.8680 -0.0900 0.1220 C 0 0 0 0 0 0 0 0 0 0 0 0 2.7070 -0.1660 0.0640 C 0 0 0 0 0 0 0 0 0 0 0 0 2.8990 1.1800 0.0910 C 0 0 0 0 0 0 0 0 0 0 0 0 1.7770 2.0340 0.1030 C 0 0 0 0 0 0 0 0 0 0 0 0 4.2710 1.7990 0.1150 C 0 0 1 0 0 0 0 0 0 0 0 0 3.8610 -1.1350 0.0100 C 0 0 2 0 0 0 0 0 0 0 0 0 5.1450 -0.3890 0.2920 C 0 0 0 0 0 0 0 0 0 0 0 0 -5.2690 -0.1420 0.1220 C 0 0 0 0 0 0 0 0 0 0 0 0 -5.9000 -1.3540 0.1040 C 0 0 0 0 0 0 0 0 0 0 0 0 -5.1650 -2.5430 0.0870 C 0 0 0 0 0 0 0 0 0 0 0 0 -3.8060 -2.5270 0.0880 C 0 0 0 0 0 0 0 0 0 0 0 0 3.9320 -1.7700 -1.3800 C 0 0 1 0 0 0 0 0 0 0 0 0 5.1100 -2.7450 -1.4360 C 0 0 0 0 0 0 0 0 0 0 0 0 -3.1810 1.1410 0.1380 C 0 0 0 0 0 0 0 0 0 0 0 0 -1.7880 -1.2570 0.0940 N 0 0 0 0 0 0 0 0 0 0 0 0 0.5270 1.5320 0.1090 N 0 0 0 0 0 0 0 0 0 0 0 0 3.6750 -2.1540 0.9940 O 0 0 0 0 0 0 0 0 0 0 0 0 1.9400 3.2440 0.1100 O 0 0 0 0 0 0 0 0 0 0 0 0 5.2770 0.8300 -0.2790 O 0 0 0 0 0 0 0 0 0 0 0 0 6.0100 -0.8590 0.9910 O 0 0 0 0 0 0 0 0 0 0 0 0 -7.2580 -1.4040 0.1040 O 0 0 0 0 0 0 0 0 0 0 0 0 -3.3360 3.1960 0.6910 H 0 0 0 0 0 0 0 0 0 0 0 0 -4.8790 2.3090 0.6900 H 0 0 0 0 0 0 0 0 0 0 0 0 -3.2530 3.0530 -1.7830 H 0 0 0 0 0 0 0 0 0 0 0 0 -4.7960 2.1660 -1.7840 H 0 0 0 0 0 0 0 0 0 0 0 0 -4.7440 3.8600 -1.2400 H 0 0 0 0 0 0 0 0 0 0 0 0 -0.8900 2.8360 -0.7480 H 0 0 0 0 0 0 0 0 0 0 0 0 -0.8740 2.8060 1.0370 H 0 0 0 0 0 0 0 0 0 0 0 0 1.2410 -1.7430 0.0540 H 0 0 0 0 0 0 0 0 0 0 0 0 4.2960 2.6440 -0.5730 H 0 0 0 0 0 0 0 0 0 0 0 0 4.4880 2.1520 1.1230 H 0 0 0 0 0 0 0 0 0 0 0 0 -5.8460 0.7710 0.1350 H 0 0 0 0 0 0 0 0 0 0 0 0 -5.6850 -3.4900 0.0740 H 0 0 0 0 0 0 0 0 0 0 0 0 -3.2530 -3.4550 0.0740 H 0 0 0 0 0 0 0 0 0 0 0 0 3.0060 -2.3070 -1.5820 H 0 0 0 0 0 0 0 0 0 0 0 0 4.0700 -0.9900 -2.1290 H 0 0 0 0 0 0 0 0 0 0 0 0 6.0360 -2.2070 -1.2340 H 0 0 0 0 0 0 0 0 0 0 0 0 4.9720 -3.5240 -0.6870 H 0 0 0 0 0 0 0 0 0 0 0 0 5.1610 -3.1970 -2.4260 H 0 0 0 0 0 0 0 0 0 0 0 0 4.3850 -2.8100 1.0200 H 0 0 0 0 0 0 0 0 0 0 0 0 -7.6510 -1.4050 -0.7790 H 0 0 0 0 0 0 0 0 0 0 0 0 21 20 1 0 0 0 0 20 14 1 0 0 0 0 19 18 2 0 0 0 0 19 7 1 0 0 0 0 18 17 1 0 0 0 0 14 25 1 1 0 0 0 28 15 2 0 0 0 0 14 15 1 0 0 0 0 14 10 1 0 0 0 0 23 7 2 0 0 0 0 23 2 1 0 0 0 0 7 9 1 0 0 0 0 29 17 1 0 0 0 0 17 16 2 0 0 0 0 15 27 1 0 0 0 0 8 10 1 0 0 0 0 8 6 2 0 0 0 0 10 11 2 0 0 0 0 2 6 1 0 0 0 0 2 1 2 0 0 0 0 6 24 1 0 0 0 0 16 9 1 0 0 0 0 9 22 2 0 0 0 0 27 13 1 0 0 0 0 11 13 1 0 0 0 0 11 12 1 0 0 0 0 1 22 1 0 0 0 0 1 5 1 0 0 0 0 22 3 1 0 0 0 0 24 12 1 0 0 0 0 24 5 1 0 0 0 0 12 26 2 0 0 0 0 3 4 1 0 0 0 0 3 30 1 0 0 0 0 3 31 1 0 0 0 0 4 32 1 0 0 0 0 4 33 1 0 0 0 0 4 34 1 0 0 0 0 5 35 1 0 0 0 0 5 36 1 0 0 0 0 8 37 1 0 0 0 0 13 38 1 0 0 0 0 13 39 1 0 0 0 0 16 40 1 0 0 0 0 18 41 1 0 0 0 0 19 42 1 0 0 0 0 20 43 1 0 0 0 0 20 44 1 0 0 0 0 21 45 1 0 0 0 0 21 46 1 0 0 0 0 21 47 1 0 0 0 0 25 48 1 0 0 0 0 29 49 1 0 0 0 0 M END): 29 ms reading 49 atoms ModelSet: haveSymmetry:false haveUnitcells:false haveFractionalCoord:false 1 model in this collection. Use getProperty "modelInfo" or getProperty "auxiliaryInfo" to inspect them. Default Van der Waals type for model set to Babel 49 atoms created ModelSet: not autobonding; use forceAutobond=true to force automatic bond creation Script completed Jmol script terminated
|
| SN-38 is an antineoplastic drug. It is the active metabolite of irinotecan (an analog of camptothecin - a topoisomerase I inhibitor) but has 1000 times more activity than irinotecan itself. In vitro cytotoxicity assays show that the potency of SN-38 relative to irinotecan varies from 2- to 2000-fold.
SN38 is formed via hydrolysis of irinotecan by carboxylesterases and metabolized via glucuronidation by UGT1A1.
The variant of UGT1A1 in ~10% of Caucasians which leads to poor metabolism of SN-38 predicts irinotecan toxicity, as it is then less easily excreted from the body in its SN-38 glucuronide form.
SN-38 and its glucuronide are lost into the bile and intestines. It can cause the symptoms of diarrhoea and myelosuppression experienced by ~25% of the patients administered irinotecan. |
|
Read full article at Wikipedia
|
InChI=1S/C22H20N2O5/c1- 3-12-13-7-11(25)5-6-17(13)23-19-14(12)9-24-18(19)8-16-15(20(24)26)10-29-21(27)22(16,28)4-2/h5-8,25,28H,3-4,9-10H2,1-2H3/t22-/m0/s1 |
| FJHBVJOVLFPMQE-QFIPXVFZSA-N |
| CCC1=C2C=C(O)C=CC2=NC2=C1CN1C2=CC2=C(COC(=O)[C@]2(O)CC)C1=O |
|
|
apoptosis inducer
Any substance that induces the process of apoptosis (programmed cell death) in multi-celled organisms.
EC 5.99.1.2 (DNA topoisomerase) inhibitor
A topoisomerase inhibitor that inhibits the bacterial enzymes of the DNA topoisomerases, Type I class (EC 5.99.1.2) that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. These bacterial enzymes reduce the topological stress in the DNA structure by relaxing negatively, but not positively, supercoiled DNA.
drug metabolite
|
|
|
antineoplastic agent
A substance that inhibits or prevents the proliferation of neoplasms.
|
|
View more via ChEBI Ontology
|
(4S)-4,11-diethyl-4,9-dihydroxy-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H,12H)-dione
|
|
10-Hydroxy-7-ethylcamptothecin
|
ChemIDplus
|
|
7-Ethyl-10-hydroxy-20(S)-camptothecin
|
ChemIDplus
|
|
7-Ethyl-10-hydroxycamptothecin
|
ChemIDplus
|
|
NK 012
|
ChemIDplus
|
|
NK-012
|
ChemIDplus
|
|
SN 38
|
ChemIDplus
|
|
SN 38 lactone
|
ChemIDplus
|
|
SN-38
|
UniProt
|
|
4829984
|
Reaxys Registry Number
|
Reaxys
|
|
86639-52-3
|
CAS Registry Number
|
KEGG COMPOUND
|
|
86639-52-3
|
CAS Registry Number
|
ChemIDplus
|
Polunin Y, Alferiev IS, Brodeur GM, Voronov A, Chorny M (2021)
Environment-Sensitive Polymeric Micelles Encapsulating SN-38 Potently Suppress Growth of Neuroblastoma Cells Exhibiting Intrinsic and Acquired Drug Resistance.
ACS pharmacology & translational science 4, 240-247 [PubMed:33615176]
[show Abstract]
Conventional treatment approaches fail to provide durable control over aggressive malignancies due to intrinsic or acquired drug resistance characteristic of high-risk disease. SN-38, a potent camptothecin analog specifically targeting DNA topoisomerase I cleavage complexes, has shown promise in preclinical studies against aggressive solid tumors. However, its clinical utility is limited by inadequate solubility in pharmaceutically acceptable vehicles and by poor chemical and metabolic stability. Micelles formulated from amphiphilic invertible polymers (AIPs) can address these issues by concomitantly enabling solubilization of water-insoluble molecular cargoes and by protecting chemically labile agents from inactivation. Furthermore, the inversion of the AIP and disruption of the carrier-drug complexes triggered by contact with cell membranes makes it possible to deliver the therapeutic payload into the cell interior without compromising its biological activity. In the present study, we characterized a novel AIP-based micellar formulation of SN-38 and evaluated its growth inhibitory effect on neuroblastoma (NB) cells derived either at diagnosis or at relapse after intensive chemoradiotherapy. Colloidally stable, drug-loaded micellar assemblies with a uniform <100 nm size were prepared using an AIP consisting of alternating blocks of poly(ethylene glycol) and polytetrahydrofuran (PEG600-PTHF650). The micellar drug applied in a low nanomolar range (10-50 nM) completely suppressed the growth of chemo-naïve NB cells even after a brief (10 min) exposure. Furthermore, extending the exposure to 24 h resulted in a profound and lasting inhibitory effect of the micellar formulation on the growth of NB cells exhibiting an acquired loss of p53 function. These results suggest that micelle-mediated delivery of SN-38 can potentially offer a new and effective strategy for treating different phases of high-risk disease, including those showing poor response to conventional therapies. | Sharifi F, Jahangiri M, Ebrahimnejad P (2021)
Synthesis of novel polymeric nanoparticles (methoxy-polyethylene glycol-chitosan/hyaluronic acid) containing 7-ethyl-10-hydroxycamptothecin for colon cancer therapy: in vitro, ex vivo and in vivo investigation.
Artificial cells, nanomedicine, and biotechnology 49, 367-380 [PubMed:33851564]
[show Abstract]
The goal of the current study was to target 7-ethyl-10-hydroxycamptothecin (SN38) orally to colon tumours by synthesizing a targeting polymer. To achieve the optimum delivery for SN38, initially methoxy-polyethylene glycol (mPEG)-chitosan was synthesized and then nanoparticles were developed through ionic gelation between mPEG-chitosan and hyaluronic acid as a ligand for cell-surface glycoprotein CD44 receptor. The SN38 was loaded in nanoparticles (SN38-NPs) using the non-covalent physical adsorption method. The size of the optimized SN38-NPs was 226.7 nm, encapsulation efficiency was 89.23% and drug content was 7.98 ± 0.54% in the optimum formulation. The attachment of mPEG to chitosan was confirmed by proton nuclear magnetic resonance. The results of differential scanning calorimetry and Fourier transforms infra-red analysis indicated that SN38 existed in amorphous form and functional groups of SN38 protected in the formulations which could be a sign of suitable encapsulation of SN38 in SN38-NPs. In vitro study indicated that SN38-NPs were more potent against the cancer cells than free SN38. The cellular uptake of SN38-NPs improved up to 1.6-fold against human colorectal adenocarcinoma (Caco-2) cells. Moreover, SN38-NPs remarkably demonstrated superior anti-tumor efficacy in contrary to pure SN38. This suggests the advantage of SN38-NPs as a potent oral drug carrier which could be further explored for clinical investigations. | Cressey P, Amrahli M, So PW, Gedroyc W, Wright M, Thanou M (2021)
Image-guided thermosensitive liposomes for focused ultrasound enhanced co-delivery of carboplatin and SN-38 against triple negative breast cancer in mice.
Biomaterials 271, 120758 [PubMed:33774525]
[show Abstract]
Triggerable nanocarriers have the potential to significantly improve the therapeutic index of existing anticancer agents. They allow for highly localised delivery and release of therapeutic cargos, reducing off-target toxicity and increasing anti-tumour activity. Liposomes may be engineered to respond to an externally applied stimulus such as focused ultrasound (FUS). Here, we report the first co-delivery of SN-38 (irinotecan's super-active metabolite) and carboplatin, using an MRI-visible thermosensitive liposome (iTSL). MR contrast enhancement was achieved by the incorporation of a gadolinium lipid conjugate in the liposome bilayer along with a dye-labelled lipid for near infrared fluorescence bioimaging. The resulting iTSL were successfully loaded with SN-38 in the lipid bilayer and carboplatin in the aqueous core - allowing co-delivery of both. The iTSL demonstrated both thermosensitivity and MR-imageability. In addition, they showed effective local targeted co-delivery of carboplatin and SN-38 after triggered release with brief FUS treatments. A single dosage induced significant improvement of anti-tumour activity (over either the free drugs or the iTSL without FUS-activation) in triple negative breast cancer xenografts tumours in mice. | Wang Y, Huang J, Wu Q, Zhang J, Ma Z, Ma S, Zhang S (2021)
Downregulation of breast cancer resistance protein by long-term fractionated radiotherapy sensitizes lung adenocarcinoma to SN-38.
Investigational new drugs 39, 458-468 [PubMed:33475937]
[show Abstract]
Chemotherapy is usually the subsequent treatment for non-small cell lung cancer patients with acquired radioresistance after long-term fractionated radiotherapy. However, few studies have focused on the selection of chemotherapeutic drugs to treat lung adenocarcinoma patients with radioresistance. Our study compared the sensitivity changes of lung adenocarcinoma cells to conventional chemotherapeutic drugs under radioresistant circumstances by using three lung adenocarcinoma cell models, which were irradiated with fractionated X-rays at a total dose of 60 Gy. The results showed that the toxicities of paclitaxel, docetaxel and SN-38 were increased in radioresistant cells. The IC50 values of docetaxel and SN-38 decreased 0 ~ 3 times and 3 ~ 36 times in radioresistant cells, respectively. Notably, the A549 radioresistant cells were approximately 36 times more sensitive to SN-38 than the parental cells. Further results revealed that the downregulation of the efflux transporter BCRP by long-term fractionated irradiation was an important factor contributing to the increased cytotoxicity of SN-38. In addition, the reported miRNAs and transcriptional factors that regulate BCRP did not participate in the downregulation. In conclusion, these results presented important data on the sensitivity changes of lung adenocarcinoma cells to chemotherapeutic drugs after acquiring radioresistance and suggested that irinotecan (the prodrug of SN-38) might be a promising drug candidate for lung adenocarcinoma patients with acquired radioresistance. | Zhao K, Guo T, Sun X, Xiong T, Ren X, Wu L, Yang R, Sun H, Shi S, Zhang J (2021)
Mechanism and optimization of supramolecular complexation-enhanced fluorescence spectroscopy for the determination of SN-38 in plasma and cells.
Luminescence : the journal of biological and chemical luminescence 36, 531-542 [PubMed:33125824]
[show Abstract]
Quantitative detection of two different forms of SN-38 in biological samples is, currently, cumbersome and difficult. A revisit to the mechanism of supramolecular complexation-enhanced fluorescence spectroscopy helps to optimize the determination of SN-38 in plasma and the cellular pharmacokinetics in A549 cells based on the supramolecular complexation. Firstly, the inclusion mechanism dominated by thermodynamic constants was determined by measuring kinetic/thermodynamic parameters (kon , koff , ΔG, ΔH, ΔS). On this basis, the best effect of fluorescence sensitization was optimized through screening the interaction conditions (cyclodextrin species and concentrations, drug levels, temperature, pH of the buffer, and reaction time). Furthermore, the proportional relationship between the concentration of the inclusion complex and the fluorescence intensity was confirmed. Finally, a highly sensitive, selective spectrofluorimetric method was established and validated for quantitative analysis of the lactone and carboxylate molecular states of SN-38 plasma levels in rats and cell membrane transfer kinetics in A549 cell lines. The limits of detection for the lactone and carboxylate forms in plasma were found to be 0.44 ng·ml-1 and 0.28 ng·ml-1 , respectively. Precision and accuracy met the requirements of biological samples analysis. The proposed detection method provided a reference for elucidating the biodistribution of SN-38. | Liu S, Hu Z, Zhang Q, Zhu Q, Chen Y, Lu W (2020)
Co-Prodrugs of 7-Ethyl-10-hydroxycamptothecin and Vorinostat with in Vitro Hydrolysis and Anticancer Effects.
ACS omega 5, 350-357 [PubMed:31956782]
[show Abstract]
7-Ethyl-10-hydroxycamptothecin (SN38) and vorinostat (SAHA) are quite promising combination therapy agents applied to the clinical treatment of cancer. In this study, we designed and synthesized a series of novel SN38-SAHA co-prodrugs, which were conjugated by four different amino acids including glycine, alanine, aminobutyric acid, and 6-aminocaproic acid. The hydrolytic reconversion rate to SN38 and SAHA critically depended on the carbon chain length, which were evaluated in PBS (pH 6.0/7.4) and plasma (human/mouse). With decreasing amino acid chain length, the hydrolytic reconversion rate increased gradually. The in vitro cytotoxicity test was evaluated by the sulforhodamine B (SRB) assay on the human lung adenocarcinoma cell line A549 and human colorectal cancer cell line HCT116. With the evaluation of stability and in vitro cytotoxicity, an appropriate linker was found, and the active drug can be released efficiently from compound 3a, which exhibited strong antiproliferative activity in A549 and HCT-116 cell lines correspondingly. These results indicated that the well-designed co-prodrug 3a and this kind of strategy can be a promising approach for anticancer therapy. | Fontaine SD, Santi AD, Reid R, Smith PC, Ashley GW, Santi DV (2020)
PLX038: a PEGylated prodrug of SN-38 independent of UGT1A1 activity.
Cancer chemotherapy and pharmacology 85, 225-229 [PubMed:31707444]
[show Abstract]
PurposeThe purpose of this study was to determine the importance of UGT1A1 activity on the metabolism and pharmacokinetics of a releasable PEG ~ SN-38 conjugate, PLX038A. Irinotecan (CPT-11) is converted to the topoisomerase 1 inhibitor SN-38 by first-pass hepatic metabolism and is converted to its glucuronide SN-38G by UGT1A1. With diminished UGT1A1 activity, the high liver exposure to SN-38 can cause increased toxicity of CPT-11. In contrast, releasable PEG ~ SN-38 conjugates-such as PLX038-release SN-38 in the vascular compartment, and only low levels of SN-38 are expected to enter the liver by transport through the OATP1B1 transporter.MethodsWe measured CPT-11 and PLX038A metabolites in plasma and bile, and determined pharmacokinetics of PLX038A in UGT1A-deficient and replete rats.ResultsCompared to CPT-11, treatment of rats with PLX038A results in very low levels of biliary SN-38 and SN-38G, a low flux through UGT1A, and a low SN-38G/SN-38 ratio in plasma. Further, the pharmacokinetics of plasma PLX038A and SN-38 in rats deficient in UGT1A is unchanged compared to normal rats.ConclusionsThe disposition of PEGylated SN-38 is independent of UGT1A activity in rats, and PLX038 may find utility in full-dose treatment of patients who are UGT1A1*28 homozygotes or have metastatic disease with coincidental or incidental liver dysfunction. | Wu Z, Li S, Cai Y, Chen F, Chen Y, Luo X (2020)
Synergistic action of doxorubicin and 7-Ethyl-10-hydroxycamptothecin polyphosphorylcholine polymer prodrug.
Colloids and surfaces. B, Biointerfaces 189, 110741 [PubMed:32032928]
[show Abstract]
There are opportunities for improvements to the efficiency and toxicity of widely used cancer chemotherapy agents such as doxorubicin (DOX·HCl) and 7-Ethyl-10-hydroxycamptothecin (SN38). We developed a safe and effective combination therapy by encapsulating DOX into micelles of a zwitterionic polymer prodrug, SN38 conjugate of poly (α-azide caprolactone-co-caprolactone)-b-poly (2-methacryloyloxyethyl phosphorylcholine [P(CL/CL-g-SN38)-b-PMPC)] which was described in our previous work. The polymer prodrug micelles displayed a higher loading capacity of DOX due to the π-π stacking effect between DOX and SN38 in comparison with the micelles self-assembled by prodrug's precursor, poly(α-azide caprolactone-co-caprolactone)-b-poly(2-methacryloyloxyethyl phosphorylcholine (P(ACL/CL)-b-PMPC). The DOX loaded prodrug micelles decelerated the release of DOX, and also prolonged its circulation. The micelles showed favorable cellular internalization by 4T1 cells. DOX loaded SN38 prodrug micelles displayed good in vitro anticancer effects owing to the synergistic action of doxorubicin and SN38 and were as effective as DOX·HCl, but with lower toxicity than DOX·HCl. Given the synergetic effects of free drug and polymer prodrug, this nanomedicine may offer a safe and effective drug delivery methodology for conventional drug formations. | Orlando BJ, Liao M (2020)
ABCG2 transports anticancer drugs via a closed-to-open switch.
Nature communications 11, 2264 [PubMed:32385283]
[show Abstract]
ABCG2 is an ABC transporter that extrudes a variety of compounds from cells, and presents an obstacle in treating chemotherapy-resistant cancers. Despite recent structural insights, no anticancer drug bound to ABCG2 has been resolved, and the mechanisms of multidrug transport remain obscure. Such a gap of knowledge limits the development of novel compounds that block or evade this critical molecular pump. Here we present single-particle cryo-EM studies of ABCG2 in the apo state, and bound to the three structurally distinct chemotherapeutics. Without the binding of conformation-selective antibody fragments or inhibitors, the resting ABCG2 adopts a closed conformation. Our cryo-EM, biochemical, and functional analyses reveal the binding mode of three chemotherapeutic compounds, demonstrate how these molecules open the closed conformation of the transporter, and establish that imatinib is particularly effective in stabilizing the inward facing conformation of ABCG2. Together these studies reveal the previously unrecognized conformational cycle of ABCG2. | Sadat SMA, Vakili MR, Paiva IM, Weinfeld M, Lavasanifar A (2020)
Development of Self-Associating SN-38-Conjugated Poly(ethylene oxide)-Poly(ester) Micelles for Colorectal Cancer Therapy.
Pharmaceutics 12, E1033 [PubMed:33138058]
[show Abstract]
The clinical use of 7-ethyl-10-hydroxy-camptothecin (SN-38), which is the active metabolite of irinotecan, has been hampered because of its practical water-insolubility. In this study, we successfully synthesized two self-associating SN-38-polymer drug conjugates to improve the water-solubility of SN-38, while retaining its anticancer activity. The polymeric micellar SN-38 conjugates were composed of either methoxy-poly(ethylene oxide)-block-poly(α-benzyl carboxylate-ε-caprolactone) conjugated to SN-38 at the PBCL end (mPEO-b-PBCL/SN-38) or mPEO-block-poly(α-carboxyl-ε-caprolactone) attached to SN-38 from the pendent-free carboxyl site (mPEO-b-PCCL/SN-38). The chemical structure of block copolymers was confirmed by 1H NMR. The physicochemical characterizations of their self-assembled structures including size, surface charge, polydispersity, critical micellar concentration, conjugation content and efficiency, morphology, kinetic stability, and in vitro release of SN-38 were compared between the two formulations. In vitro anticancer activities were evaluated by measuring cellular cytotoxicity and caspase activation by MTS and Caspase-Glo 3/7 assays, respectively. The hemolytic activity of both micellar structures against rat red blood cells was also measured. The results showed the formation of SN-38-polymeric micellar conjugates at diameters < 50 nm with a narrow size distribution and sustained release of SN-38 for both structures. The loading content of SN-38 in mPEO-b-PBCL and mPEO-b-PCCL were 11.47 ± 0.10 and 12.03 ± 0.17 (% w/w), respectively. The mPEO-b-PBCL/SN-38, end-capped micelles were kinetically more stable than mPEO-b-PCCL/SN-38. The self-assembled mPEO-b-PBCL/SN-38 and mPEO-b-PCCL/SN-38 micelles resulted in significantly higher cytotoxic effects than irinotecan against human colorectal cancer cell lines HCT116, HT-29, and SW20. The CRC cells were found to be 70-fold to 330-fold more sensitive to micellar SN-38 than irinotecan, on average. Both SN-38-incorporated micelles showed two-fold higher caspase-3/7 activation levels than irinotecan. The mPEO-b-PBCL/SN-38 micelles were not hemolytic, but mPEO-b-PCCL/SN-38 showed some hemolysis. The overall results from this study uphold mPEO-b-PBCL/SN-38 over mPEO-b-PCCL/SN-38 micellar formulation as an effective delivery system of SN-38 that warrants further preclinical investigation. | Sun R, Zhu L, Li L, Song W, Gong X, Qi X, Wang Y, Ghose R, Gao S, Hu M, Liu Z (2020)
Irinotecan-mediated diarrhea is mainly correlated with intestinal exposure to SN-38: Critical role of gut Ugt.
Toxicology and applied pharmacology 398, 115032 [PubMed:32387182]
[show Abstract]
Background and purposeIrinotecan-induced diarrhea (IID) results from intestinal damages by its active metabolite SN-38. Alleviation of these damages has focused on lowering luminal SN-38 concentrations. However, it is unclear if the enteric bioavailability of SN-38 is mostly dependent on luminal SN-38 concentrations.Experimental approachIrinotecan (50 mg/kg, i.p. once daily for 6 days) was administered to female wildtype FVB, Mdr1a (-/-), Mrp2 (-/-) and Bcrp1 (-/-) mice for pharmacokinetic (PK), toxicokinetic (TK) and biodistribution studies. Plasma PK/TK profiles and tissues drug distribution were determined after first or sixth daily doses, along with activities of blood and gut esterases and intestinal Ugts. Caco-2 cells and bile-cannulate mice were used to further investigate intestinal and biliary disposition of irinotecan and its metabolites.Key resultsSignificant differences in IID severity were observed with the susceptible rank of Bcrp1(-/-) > wildtype FVB > Mdr1a(-/-) > Mrp2(-/-). This rank order did not correlate with biliary excretion rates of SN-38/SN-38G. Rather, the severity was best correlated (R = 0.805) with the intestinal ratio of Css SN-38/SN-38G, a measure of gut Ugt activity. On the contrary, IID was poorly correlated with plasma AUC ratio of SN-38/SN-38G (R = 0.227). Increased intestinal esterase activities due to repeated dosing and gut efflux transporter functionality are the other key factors that determine SN-38 enteric exposures.Conclusion and implicationsIntestinal SN-38 exposure is mainly affected by intestinal Ugt activities and blood esterase activities, and strongly correlated with severity of IID. Modulating intestinal SN-38 concentration and gut Ugt expression should be the focus of future studies to alleviate IID. | Yang W, Yang Z, Liu J, Liu D, Wang Y (2019)
Development of a method to quantify total and free irinotecan and 7-ethyl-10-hydroxycamptothecin (SN-38) for pharmacokinetic and bio-distribution studies after administration of irinotecan liposomal formulation.
Asian journal of pharmaceutical sciences 14, 687-697 [PubMed:32104495]
[show Abstract]
In 2015, liposomal formulation of irinotecan (ONIVYDE) has been approved by FDA and widely applied in the treatment of pancreatic cancer. ONIVYDE is a novel liposome formulation, entrapping CPT-11 in the aqueous core of vesicles using a modified gradient loading method. Due to toxicity concerns, it is essential to explore a rapid and reliable method to effectively isolate and quantify the non-liposomal, namely, free CPT-11and total CPT-11 in plasma. This study focuses on separation of non-liposomal CPT-11, evaluation of the pharmacokinetics of free CPT-11 and total CPT-11 and bio-distribution after intravenous administration of CPT-11 liposome. Free CPT-11 in plasma was separated by solid-phase extraction (SPE). The amount of total CPT-11 and main metabolite 7-ethyl-10-hydroxycamptothecin (SN-38) in plasma was quantified by ultra-performance liquid chromatography-MS/MS. The calibration curves fitted well and lower limit of quantitation for SN-38, free CPT-11, total CPT-11 and CPT-11 in tissue and were 5 ng/ml, 10 ng/ml, 4.44 ng/ml and 25 ng/ml respectively. The recoveries, precision and accuracy of the method appear satisfactory. Using this method, the pharmacokinetics and bio-distribution of CPT-11 liposome formulation after an intravenous dose of 2.5 mg/kg were then investigated. | Fontaine SD, Hann B, Reid R, Ashley GW, Santi DV (2019)
Species-specific optimization of PEG~SN-38 prodrug pharmacokinetics and antitumor effects in a triple-negative BRCA1-deficient xenograft.
Cancer chemotherapy and pharmacology 84, 729-738 [PubMed:31321449]
[show Abstract]
PurposeOptimal efficacy of a macromolecular prodrug requires balancing the rate of drug release with the rate of prodrug elimination. Since circulating macromolecules have different elimination rates in different species, a prodrug optimal for one species will likely not be for another. The objectives of this work were (a) to develop an approach to optimize pharmacokinetics of a PEG~SN-38 prodrug in a particular species, (b) to use the approach to predict the pharmacokinetics of various prodrugs of SN-38 in the mouse and human, and (c) to develop a PEG~SN-38 conjugate that is optimized for mouse tumor models.MethodsWe developed models that describe the pharmacokinetics of a drug released from a prodrug by the relationship between the rates of drug release and elimination of the prodrug. We tested the model by varying the release rate of SN-38 from PEG~SN-38 conjugates in the setting of a constant prodrug elimination rate in the mouse. Finally, we tested the antitumor efficacy of a PEG~SN-38 optimized for the mouse.ResultsOptimization of a PEG~SN-38 prodrug was achieved by adjusting the rate of SN-38 release such that the ratio of t1/2,β of released SN-38 to the t1/2 of prodrug elimination was 0.2-0.8. Using this approach, we could rationalize the efficacy of previous PEGylated SN-38 prodrugs in the mouse and human. Finally, a mouse-optimized PEG~SN-38 showed remarkable antitumor activity in BRCA1-deficient MX-1 xenografts; a single dose gave tumor regression, suppression, and shrinkage of massive tumors.ConclusionsThe efficacy of a macromolecular prodrug can be optimized for a given species by balancing the rate of drug release from the carrier with the rate of prodrug elimination. | Kodawara T, Higashi T, Negoro Y, Kamitani Y, Igarashi T, Watanabe K, Tsukamoto H, Yano R, Masada M, Iwasaki H, Nakamura T (2016)
The Inhibitory Effect of Ciprofloxacin on the β-Glucuronidase-mediated Deconjugation of the Irinotecan Metabolite SN-38-G.
Basic & clinical pharmacology & toxicology 118, 333-337 [PubMed:26518357]
[show Abstract]
The enterohepatic recycling of a drug consists of its biliary excretion and intestinal reabsorption, which is sometimes accompanied by hepatic conjugation and intestinal deconjugation reactions. β-Glucuronidase, an intestinal bacteria-produced enzyme, can break the bond between a biliary excreted drug and glucuronic acid. Antibiotics such as ciprofloxacin can reduce the enterohepatic recycling of glucuronide-conjugated drugs. In this study, we established an in vitro system to evaluate the β-glucuronidase-mediated deconjugation of the irinotecan metabolite SN-38-G to its active SN-38 form and the effect of ciprofloxacin thereon. SN-38 formation increased in a time-dependent manner from 5 to 30 min. in the presence of β-glucuronidase. Ciprofloxacin and phenolphthalein-β-D-glucuronide (PhePG), a typical β-glucuronidase substrate, significantly decreased SN-38-G deconjugation and, hence SN-38 formation. Similarly, the antibiotics enoxacin and gatifloxacin significantly inhibited the conversion of SN-38-G to SN-38, which was not observed for levofloxacin, streptomycin, ampicillin and amoxicillin/clavulanate. Ciprofloxacin showed a dose-dependent inhibitory effect on the β-glucuronidase-mediated conversion of SN-38-G to SN-38 with a half-maximal inhibitory concentration (IC50 ) value of 83.8 μM. PhePG and ciprofloxacin afforded the inhibition in a competitive and non-competitive manner, respectively. These findings suggest that the reduction in the serum SN-38 concentration following co-administration of ciprofloxacin during irinotecan treatment is due, at least partly, to the decreased enterohepatic circulation of SN-38 through the non-competitive inhibition of intestinal β-glucuronidase-mediated SN-38-G deconjugation. | Casadó A, Giuffrida MC, Sagristá ML, Castelli F, Pujol M, Alsina MA, Mora M (2016)
Langmuir monolayers and Differential Scanning Calorimetry for the study of the interactions between camptothecin drugs and biomembrane models.
Biochimica et biophysica acta 1858, 422-433 [PubMed:26656185]
[show Abstract]
CPT-11 and SN-38 are camptothecins with strong antitumor activity. Nevertheless, their severe side effects and the chemical instability of their lactone ring have questioned the usual forms for its administration and have focused the current research on the development of new suitable pharmaceutical formulations. This work presents a biophysical study of the interfacial interactions of CPT-11 and SN-38 with membrane mimetic models by using monolayer techniques and Differential Scanning Calorimetry. The aim is to get new insights for the understanding of the bilayer mechanics after drug incorporation and to optimize the design of drug delivery systems based on the formation of stable bilayer structures. Moreover, from our knowledge, the molecular interactions between camptothecins and phospholipids have not been investigated in detail, despite their importance in the context of drug action. The results show that neither CPT-11 nor SN-38 disturbs the structure of the complex liposome bilayers, despite their different solubility, that CPT-11, positively charged in its piperidine group, interacts electrostatically with DOPS, making stable the incorporation of a high percentage of CPT-11 into liposomes and that SN-38 establishes weak repulsive interactions with lipid molecules that modify the compressibility of the bilayer without affecting significantly neither the lipid collapse pressure nor the miscibility pattern of drug-lipid mixed monolayers. The suitability of a binary and a ternary lipid mixture for encapsulating SN-38 and CPT-11, respectively, has been demonstrated. | Monterrubio C, Pascual-Pasto G, Cano F, Vila-Ubach M, Manzanares A, Schaiquevich P, Tornero JA, Sosnik A, Mora J, Carcaboso AM (2016)
SN-38-loaded nanofiber matrices for local control of pediatric solid tumors after subtotal resection surgery.
Biomaterials 79, 69-78 [PubMed:26695118]
[show Abstract]
In addition to surgery, local tumor control in pediatric oncology requires new treatments as an alternative to radiotherapy. SN-38 is an anticancer drug with proved activity against several pediatric solid tumors including neuroblastoma, rhabdomyosarcoma and Ewing sarcoma. Taking advantage of the extremely low aqueous solubility of SN-38, we have developed a novel drug delivery system (DDS) consisting of matrices made of poly(lactic acid) electrospun polymer nanofibers loaded with SN-38 microcrystals for local release in difficult-to-treat pediatric solid tumors. To model the clinical scenario, we conducted extensive preclinical experiments to characterize the biodistribution of the released SN-38 using microdialysis sampling in vivo. We observed that the drug achieves high concentrations in the virtual space of the surgical bed and penetrates a maximum distance of 2 mm within the tumor bulk. Subsequently, we developed a model of subtotal tumor resection in clinically relevant pediatric patient-derived xenografts and used such models to provide evidence of the activity of the SN-38 DDS to inhibit tumor regrowth. We propose that this novel DDS could represent a potential future strategy to avoid harmful radiation therapy as a primary tumor control together with surgery. | Faltas B, Goldenberg DM, Ocean AJ, Govindan SV, Wilhelm F, Sharkey RM, Hajdenberg J, Hodes G, Nanus DM, Tagawa ST (2016)
Sacituzumab Govitecan, a Novel Antibody--Drug Conjugate, in Patients With Metastatic Platinum-Resistant Urothelial Carcinoma.
Clinical genitourinary cancer 14, e75-9 [PubMed:26541586]
[show Abstract]
Patients with metastatic, platinum-resistant urothelial carcinoma (PRUC) have no Food and Drug Administration-approved therapies. The response rates to second-line chemotherapy have generally been < 20%, with a median overall survival of < 1 year. We report our experience with 6 heavily pretreated patients with advanced PRUC (ClinicalTrials.gov identifier NCT01631552) with the novel antibody-drug conjugate, sacituzumab govitecan (IMMU-132). This antibody-drug conjugate comprises the active metabolite of irinotecan, SN-38, conjugated to an anti-Trop-2 antibody. Trop-2 is widely expressed in ≤ 83% of urothelial carcinomas. Of the 6 patients, 3 had a clinically significant response (progression-free survival, 6.7 to 8.2 months; overall survival, 7.5+ to 11.4+ months). Sacituzumab govitecan was well tolerated. Because of these results, a phase II trial has been initiated. The present report highlights the promise of antibody-drug conjugates, such as sacituzumab govitecan, as a novel therapeutic strategy for the treatment of PRUC. | Koliqi R, Dimchevska S, Geskovski N, Petruševski G, Chacorovska M, Pejova B, Hristov DR, Ugarkovic S, Goracinova K (2016)
PEO-PPO-PEO/Poly(DL-lactide-co-caprolactone) Nanoparticles as Carriers for SN-38: Design, Optimization and Nano-Bio Interface Interactions.
Current drug delivery 13, 339-352 [PubMed:26728136]
[show Abstract]
Encapsulation of extremely hydrophobic substances such as SN-38 into nanoparticles, is a promising approach to solve the solubility issue and enable drug administration. Moreover, nanocarriers' tumor homing behavior, targeted and controlled release at the site of action will optimize therapeutic potency and decrease toxicity of the incorporated drug substance. However, the enormous drug hydrophobicity might limit the capacity for encapsulation as the premature drug precipitation will contribute to fast free drug crystal growth, low drug incorporation and huge waste of the active material. In this article we defined the optimal region for manufacturing of SN-38 loaded PEO-PPO-PEO/P(DL)LCL nanoparticles (NPs) with high efficacy of encapsulation, suitable particle size and different surface properties, using D-optimal design and nanoprecipitation as production method. Further we made an approach to investigate the interactions with macromolecules at the nano-bio interface which are predetermined by the physico-chemical and surface properties of the NPs, and are important determinants for the biological identity of the nanoparticles, the potential for evasion of the physiological barriers and the efficacy of localization at the site of action. Here we present in depth analysis of the behavior of two types of nanoparticles with different surface properties through structured protein interaction and bioreactivity experiments in order to presuppose NP performance and toxicological profile in biological environment. | Zhang R, Saito R, Mano Y, Sumiyoshi A, Kanamori M, Sonoda Y, Kawashima R, Tominaga T (2016)
Convection-enhanced delivery of SN-38-loaded polymeric micelles (NK012) enables consistent distribution of SN-38 and is effective against rodent intracranial brain tumor models.
Drug delivery 23, 2780-2786 [PubMed:26330269]
[show Abstract]
Convection-enhanced delivery (CED) of therapeutic agents is a promising local delivery technique that has been extensively studied as a treatment for CNS diseases over the last two decades. One continuing challenge of CED is accurate and consistent delivery of the agents to the target. The present study focused on a new type of therapeutic agent, NK012, a novel SN-38-loaded polymeric micelle. Local delivery profiles of NK012 and SN-38 were studied using rodent brain and intracranial rodent brain tumor models. First, the cytotoxicity of NK012 against glioma cell lines was determined in vitro. Proliferations of glioma cells were significantly reduced after exposure to NK012. Then, the distribution and local toxicity after CED delivery of NK012 and SN-38 were evaluated in vivo. Volume of distribution of NK012 after CED was much larger than that of SN-38. Histological examination revealed minimum brain tissue damage in rat brains after delivery of 40 µg NK012 but severe damage with SN-38 at the same dose. Subsequently, the efficacy of NK012 delivered via CED was tested in 9L and U87MG rodent orthotopic brain tumor models. CED of NK012 displayed excellent efficacy in the 9L and U87MG orthotopic brain tumor models. Furthermore, NK012 and gadolinium diamide were co-delivered via CED to monitor the NK012 distribution using MRI. Volume of NK012 distribution evaluated by histology and MRI showed excellent agreement. CED of NK012 represents an effective treatment option for malignant gliomas. MRI-guided CED of NK012 has potential for clinical application. | Fujita D, Saito Y, Nakanishi T, Tamai I (2016)
Organic Anion Transporting Polypeptide (OATP)2B1 Contributes to Gastrointestinal Toxicity of Anticancer Drug SN-38, Active Metabolite of Irinotecan Hydrochloride.
Drug metabolism and disposition: the biological fate of chemicals 44, 1-7 [PubMed:26526067]
[show Abstract]
Gastrointestinal toxicity, such as late-onset diarrhea, is a significant concern in irinotecan hydrochloride (CPT-11)-containing regimens. Prophylaxis of late-onset diarrhea has been reported with use of Japanese traditional (Kampo) medicine containing baicalin and with the antibiotic cefixime, and this has been explained in terms of inhibition of bacterial deconjugation of SN-38-glucuronide since unconjugated SN-38 (active metabolite of CPT-11) is responsible for the gastrointestinal toxicity. It is also prerequisite for SN-38 to be accumulated in intestinal tissues to exert toxicity. Based on the fact that liver-specific organic anion transporting polypeptide (OATP)1B1, a member of the same family as OATP2B1, is known to be involved in hepatic transport of SN-38, we hypothesized that intestinal transporter OATP2B1 contributes to the accumulation of SN-38 in gastrointestinal tissues, and its inhibition would help prevent associated toxicity. We found that uptake of SN-38 by OATP2B1-expressing Xenopus oocytes was significantly higher than that by control oocytes. OATP2B1-mediated uptake of SN-38 was saturable, pH dependent, and decreased in the presence of baicalin, cefixime, or fruit juices such as apple juice. In vivo gastrointestinal toxicity of SN-38 in mice caused by oral administration for consecutive 5 days was prevented by coingestion of apple juice. Thus, OATP2B1 contributes to the uptake of SN-38 by intestinal tissues, triggering gastrointestinal toxicity. So, in addition to the reported inhibition of bacterial β-glucuronidase by cefixime or baicalin, inhibition of OATP2B1 may also contribute to prevention of gastrointestinal toxicity. Apple juice may be helpful for prophylaxis of late-onset diarrhea observed in CPT-11 therapy without disturbance of the intestinal microflora. | Fujita K, Masuo Y, Okumura H, Watanabe Y, Suzuki H, Sunakawa Y, Shimada K, Kawara K, Akiyama Y, Kitamura M, Kunishima M, Sasaki Y, Kato Y (2016)
Increased Plasma Concentrations of Unbound SN-38, the Active Metabolite of Irinotecan, in Cancer Patients with Severe Renal Failure.
Pharmaceutical research 33, 269-282 [PubMed:26337772]
[show Abstract]
PurposeDelayed plasma concentration profiles of the active irinotecan metabolite SN-38 were observed in cancer patients with severe renal failure (SRF), even though SN-38 is eliminated mainly via the liver. Here, we examined the plasma concentrations of unbound SN-38 in such patients.MethodsPlasma unbound concentrations were examined by ultrafiltration. Physiologically-based pharmacokinetic (PBPK) models of irinotecan and SN-38 were established to quantitatively assess the principal mechanism for delayed SN-38 elimination.ResultsThe area under the plasma unbound concentration-time curve (AUC(u)) of SN-38 in SRF patients was 4.38-fold higher than that in normal kidney patients. The unbound fraction of SN-38 was also 2.6-fold higher in such patients, partly because SN-38 protein binding was displaced by the uremic toxin 3-carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF). This result was supported by correlation of the unbound fraction of SN-38 with the plasma CMPF concentration, which negatively correlated with renal function. PBPK modeling indicated substantially reduced influx of SN-38 into hepatocytes and approximately one-third irinotecan dose for SRF patients to produce an unbound concentration profile of SN-38 similar to normal kidney patients.ConclusionThe AUC(u) of SN-38 in SRF cancer patients is much greater than that of normal kidney patients primarily because of the reduced hepatic uptake of SN-38. | Xu G, Shi C, Guo D, Wang L, Ling Y, Han X, Luo J (2015)
Functional-segregated coumarin-containing telodendrimer nanocarriers for efficient delivery of SN-38 for colon cancer treatment.
Acta biomaterialia 21, 85-98 [PubMed:25910639]
[show Abstract]
Four coumarin-containing telodendrimers (denoted as P-I, P-II, P-III and P-IV) were designed and synthesized to self-assemble into the corresponding nanoparticles. Of those, two nanoparticles (P-II and P-IV micelles) were screened and selected for targeted drug delivery of 7-ethyl-10-hydroxy camptothecin (SN-38), a prominent and efficacious anticancer agent, for the treatment of colon cancers. The nanoparticle encapsulation significantly increased the solubility of SN-38 in aqueous solution. Dynamic light scattering (DLS) showed the size of these SN-38 nanoparticles to be around 50 nm, and rod-shaped micelles were observed using transmission electron microscopy (TEM). These two novel nanoformulations of SN-38/P-II and SN-38/P-IV were found to exhibit similar in vitro cytotoxic activity against colon cancer cells as the free drug (SN-38 in DMSO) and were 500-fold more potent than irinotecan (a prodrug of SN-38). In addition, near infrared fluorescent (NIRF) optical imaging was utilized to monitor the tumor targeted delivery of SN-38/NPs via co-loading a NIRF dye. It was demonstrated that these NPs preferentially accumulated in tumors when compared to healthy tissue. A pharmacokinetics study showed that SN-38 micelle formulations had a longer circulating time in blood than irinotecan. Furthermore, SN-38 loaded nanoformulations exhibit superior anti-tumor efficacy when compared with irinotecan at equivalent SN-38 dose in HT-29 human colon cancer xenograft models. | Li W, Xing Y, Liu Y (2015)
Inhibition of SN-38 glucuronidation by gefitinib and its metabolite.
Cancer chemotherapy and pharmacology 75, 1253-1260 [PubMed:25917289]
[show Abstract]
Drug combinations including irinotecan and gefitinib have been evaluated in clinical trials. SN-38 is the active metabolite of irinotecan, and the increase in its concentration due to drug interactions will result in increased clinical toxicity. We aimed to investigate the effects of gefitinib and its predominant metabolite observed in human plasma, O-desmethyl-gefitinib (DMG), on SN-38 glucuronidation. Our data indicated that both gefitinib and DMG are potent inhibitors of SN-38 glucuronidation via UGT1A1 inhibition. It is predicted from in vitro data that gefitinib administered at 700 mg/day may result in about 149 % increase in SN-38 AUC, but there is no significant effects on SN-38 AUC at lower concentrations. Our prediction study provides a basis for design of clinical studies for the development and optimization of this combination. | Sharkey RM, McBride WJ, Cardillo TM, Govindan SV, Wang Y, Rossi EA, Chang CH, Goldenberg DM (2015)
Enhanced Delivery of SN-38 to Human Tumor Xenografts with an Anti-Trop-2-SN-38 Antibody Conjugate (Sacituzumab Govitecan).
Clinical cancer research : an official journal of the American Association for Cancer Research 21, 5131-5138 [PubMed:26106073]
[show Abstract]
PurposeThis study examined the delivery of SN-38 to Trop-2-expressing tumors and assessed the constitutive products in the serum, liver, and small intestine in nude mice bearing human tumor xenografts (Capan-1 or NCI-N87) given a single injection of irinotecan (40 mg/kg; ∼ 0.8 mg/mouse, containing ∼ 460 μg SN-38 equivalents) or sacituzumab govitecan (IMMU-132), an antibody-drug conjugate composed of a humanized anti-Trop-2 IgG coupled site specifically with an average of 7.6 molecules of SN-38.Experimental designAt select times, tissues were extracted and concentrations of the products measured by reversed-phase high-performance liquid chromatography (HPLC).ResultsIn serum, >98% irinotecan cleared within 5 minutes; peak levels of SN-38 and SN-38G (glucuronidated SN-38) were detected in equal amounts at this time, and no longer detected after 6 to 8 hours. IMMU-132 was detected in the serum over 3 days, and at each interval, ≥ 95% of total SN-38 was bound to the antibody. Intact IMMU-132 cleared with a half-life of 14 hours, which closely reflected the in vitro rate of SN-38 released from the conjugate in mouse serum (i.e., 17.5 hours), whereas the IgG portion of the conjugate cleared with a half-life of 67.1 hours. In vitro and in vivo studies disclosed IgG-bound SN-38 was protected from glucuronidation. Area under the curve (AUC) analysis indicated that IMMU-132 delivers 20-fold to as much as 136-fold more SN-38 to tumors than irinotecan, with tumor:blood ratios favoring IMMU-132 by 20- to 40-fold. Intestinal concentrations of SN-38/SN-38G also were 9-fold lower with IMMU-132.ConclusionsThese studies confirm a superior SN-38 tumor delivery by IMMU-132 compared with irinotecan. | Vejjasilpa K, Nasongkla N, Manaspon C, Larbcharoensub N, Boongird A, Hongeng S, Israsena N (2015)
Antitumor efficacy and intratumoral distribution of SN-38 from polymeric depots in brain tumor model.
Experimental biology and medicine (Maywood, N.J.) 240, 1640-1647 [PubMed:26080460]
[show Abstract]
We investigate antitumor efficacy and 2D and 3D intratumoral distribution of 7-ethyl-10-hydroxycamptothecin (SN-38) from polymeric depots inside U-87MG xenograft tumor model in nude mice. Results showed that polymeric depots could be used to administer and controlled release of a large amount of SN-38 directly to the brain tumor model. SN-38 released from depots suppressed tumor growth, where the extent of suppression greatly depended on doses and the number of depot injections. Tumor suppression of SN-38 from depots was three-fold higher in animals which received double injections of depots at high dose (9.7 mg of SN-38) compared to single injection (2.2 mg). H&E staining of tumor sections showed that the area of tumor cell death/survival of the former group was two-fold higher than those of the latter group. Fluorescence imaging based on self-fluorescent property of SN-38 was used to evaluate the intratumoral distribution of this drug compared to histological results. The linear correlation between fluorescence intensity and the amount of SN-38 allowed quantitative determination of SN-38 in tumor tissues. Results clearly showed direct correlation between the amount of SN-38 in tumor sections and cancer cell death. Moreover, 3D reconstruction representing the distribution of SN-38 in tumors was obtained. Results from this study suggest the rationale for intratumoral drug administration and release of drugs inside tumor, which is necessary to design drug delivery systems with efficient antitumor activity. | Essa S, Daoud J, Lafleur M, Martel S, Tabrizian M (2015)
SN-38 active loading in poly(lactic-co-glycolic acid) nanoparticles and assessment of their anticancer properties on COLO-205 human colon adenocarcinoma cells.
Journal of microencapsulation 32, 784-793 [PubMed:26381056]
[show Abstract]
SN-38 is a highly effective drug against many cancers. The development of an optimal delivery system for SN-38 is extremely challenging due to its low solubility and labile lactone ring. Herein, SN-38 encapsulated in poly(D,L-lactide-co-glycolide) nanoparticles (NPs) is introduced to enhance its solubility, stability and cellular uptake. SN-38-loaded NPs prepared by spontaneous emulsification solvent diffusion (SESD) method had an average diameter of 310 nm, a zeta potential of -9.69 mV and a loading efficiency of 71%. They were able to protect the active lactone ring of SN-38 against inactivation under physiological condition. A colorectal adenocarcinoma cell line (COLO-205) was used to assess the NPs effects on cytotoxicity and cellular uptake. Result showed a significant decreased cell proliferation and cell apoptosis. These results suggest that these SN-38-loaded NPs can be an effective delivery system for the treatment of colon cancer and potentially for other types of cancers. | Zhu X, Ni S, Xia T, Yao Q, Li H, Wang B, Wang J, Li X, Su W (2015)
Anti-Neoplastic Cytotoxicity of SN-38-Loaded PCL/Gelatin Electrospun Composite Nanofiber Scaffolds against Human Glioblastoma Cells In Vitro.
Journal of pharmaceutical sciences 104, 4345-4354 [PubMed:26505475]
[show Abstract]
Electrospun poly(ε-caprolactone) (PCL)/gelatin (GT) scaffolds were developed to provide controlled release of 7-ethyl-10-hydroxy camptothecin (SN-38). Acetic acid was introduced to improve the miscibility of PCL and GT to produce a homogeneous nanofiber membrane mixture. The effect of SN-38 content in binary mixtures on processability, fiber morphology, water sorption, swelling, and drug release was investigated. Electrospun PCL/GT blend nonwoven fibers showed fiber surface roughness, decreased PCL crystallinity, and increased swelling with increasing drug content of 1, 2, and 4 wt %. Additionally, increasing the SN-38 concentration reduced the degradation rate of the GT. Furthermore, we hypothesize the existence of a drug content saturation point in the monoaxial fiber to explain the different drug release patterns of PG2 compared with those of PG1 and PG4. The matrix also showed good biodegradation and anti-tumor function. Our results demonstrate that SN-38-loaded PCL/GT fibers can be obtained by electrospinning. The SN-38-loaded fibers merit further evaluation as a means to potentially prevent locoregional recurrence following surgical tumor resection. | Nakatsuji M, Inoue H, Kohno M, Saito M, Tsuge S, Shimizu S, Ishida A, Ishibashi O, Inui T (2015)
Human Lipocalin-Type Prostaglandin D Synthase-Based Drug Delivery System for Poorly Water-Soluble Anti-Cancer Drug SN-38.
PloS one 10, e0142206 [PubMed:26529243]
[show Abstract]
Lipocalin-type prostaglandin D synthase (L-PGDS) is a member of the lipocalin superfamily, which is composed of secretory transporter proteins, and binds a wide variety of small hydrophobic molecules. Using this function, we have reported the feasibility of using L-PGDS as a novel drug delivery vehicle for poorly water-soluble drugs. In this study, we show the development of a drug delivery system using L-PGDS, one that enables the direct clinical use of 7-ethyl-10-hydroxy-camptothecin (SN-38), a poorly water-soluble anti-cancer drug. In the presence of 2 mM L-PGDS, the concentration of SN-38 in PBS increased 1,130-fold as compared with that in PBS. Calorimetric experiments revealed that L-PGDS bound SN-38 at a molecular ratio of 1:3 with a dissociation constant value of 60 μM. The results of an in vitro growth inhibition assay revealed that the SN-38/L-PGDS complexes showed high anti-tumor activity against 3 human cancer cell lines, i.e., Colo201, MDA-MB-231, and PC-3 with a potency similar to that of SN-38 used alone. The intravenous administration of SN-38/L-PGDS complexes to mice bearing Colo201 tumors showed a pronounced anti-tumor effect. Intestinal mucositis, which is one of the side effects of this drug, was not observed in mice administered SN-38/L-PGDS complexes. Taken together, L-PGDS enables the direct usage of SN-38 with reduced side effects. | Vangara KK, Ali HI, Lu D, Liu JL, Kolluru S, Palakurthi S (2014)
SN-38-cyclodextrin complexation and its influence on the solubility, stability, and in vitro anticancer activity against ovarian cancer.
AAPS PharmSciTech 15, 472-482 [PubMed:24477982]
[show Abstract]
SN-38, an active metabolite of irinotecan, is up to 1,000-fold more potent than irinotecan. But the clinical use of SN-38 is limited by its extreme hydrophobicity and instability at physiological pH. To enhance solubility and stability, SN-38 was complexed with different cyclodextrins (CDs), namely, sodium sulfobutylether β-cyclodextrin (SBEβCD), hydroxypropyl β-cyclodextrin, randomly methylated β-cyclodextrin, and methyl β-cyclodextrin, and their influence on SN-38 solubility, stability, and in vitro cytotoxicity was studied against ovarian cancer cell lines (A2780 and 2008). Phase solubility studies were conducted to understand the pattern of SN-38 solubilization. SN-38-βCD complexes were characterized by differential scanning calorimetry (DSC), X-ray powder diffraction analysis (XRPD), and Fourier transform infrared (FTIR). Stability of SN-38-SBEβCD complex in pH 7.4 phosphate-buffered saline was evaluated and compared against free SN-38. Phase solubility studies revealed that SN-38 solubility increased linearly as a function of CD concentration and the linearity was characteristic of an AP-type system. Aqueous solubility of SN-38 was enhanced by about 30-1,400 times by CD complexation. DSC, XRPD, and FTIR studies confirmed the formation of inclusion complexes, and stability studies revealed that cyclodextrin complexation significantly increased the hydrolytic stability of SN-38 at physiological pH 7.4. Cytotoxicity of SN-38-SBEβCD complex was significantly higher than SN-38 and irinotecan in both A2780 and 2008 cell lines. Results suggest that SBEβCD encapsulated SN-38 deep into the cavity forming stable inclusion complex and as a result increased the solubility, stability, and cytotoxicity of SN-38. It may be concluded that preparation of inclusion complexes with SBEβCD is a suitable approach to overcome the solubility and stability problems of SN-38 for future clinical applications. | Nittayacharn P, Manaspon C, Hongeng S, Nasongkla N (2014)
HPLC analysis and extraction method of SN-38 in brain tumor model after injected by polymeric drug delivery system.
Experimental biology and medicine (Maywood, N.J.) 239, 1619-1629 [PubMed:24990485]
[show Abstract]
SN-38 is a highly potent anticancer drug but its poor solubility in aqueous solvent and adverse side effects limit clinical applications. To overcome these limitations, SN-38-loaded-injectable drug delivery depots have been intratumorally administered in xenograft tumor model in nude mice. The extraction and high performance liquid chromatography (HPLC) were performed in order to determine the amount of SN-38 inside tumors. SN-38 was extracted from tumors using DMSO. HPLC analysis was validated and resulted in linearity over the concentration range from 0.03 to 150 µg/mL (r(2) ≥ 0.998). Lower limit of detection (LLOD) and lower limit of quantitation (LLOQ) were 0.308 µg/mL and 1.02 µg/mL, respectively. The extraction efficiency (% recovery) of SN-38 in porcine tissues was similar to that of tumors which provided more than 90% recovery in all concentrations. Moreover, the variability of precision and accuracy within and between-day were less than 15%. Therefore, this extraction and HPLC protocol was applied to determine the amount of SN-38 in tumors. Results show higher remaining amount of SN-38 in tumor from SN-38-loaded polymeric depots than that of SN-38 solution. These results reveal that SN-38-loaded polymeric depots can prevent the leakage of free-drug out of tumors and can sustain higher level of SN-38 inside tumor. Thus, the therapeutic efficacy can be elevated by SN-38-loaded polymeric depots. | Santi DV, Schneider EL, Ashley GW (2014)
Macromolecular prodrug that provides the irinotecan (CPT-11) active-metabolite SN-38 with ultralong half-life, low C(max), and low glucuronide formation.
Journal of medicinal chemistry 57, 2303-2314 [PubMed:24494988]
[show Abstract]
We have recently reported a chemical approach for half-life extension that utilizes β-eliminative linkers to attach amine-containing drugs or prodrugs to macromolecules. The linkers release free drug or prodrug over periods ranging from a few hours to over 1 year. We adapted these linkers for use with phenol-containing drugs. Here, we prepared PEG conjugates of the irinotecan (CPT-11) active metabolite SN-38 via a phenyl ether that release the drug with predictable long half-lives. Pharmacokinetic studies in the rat indicate that, in contrast to other SN-38 prodrugs, the slowly released SN-38 shows a very low C(max), is kept above target concentrations for extended periods, and forms very little SN-38 glucuronide (the precursor of enterotoxic SN-38). The low SN-38 glucuronide is attributed to low hepatic uptake of SN-38. These macromolecular prodrugs have unique pharmacokinetic profiles that may translate to less intestinal toxicity and interpatient variability than the SN-38 prodrugs thus far studied. | Iusuf D, Ludwig M, Elbatsh A, van Esch A, van de Steeg E, Wagenaar E, van der Valk M, Lin F, van Tellingen O, Schinkel AH (2014)
OATP1A/1B transporters affect irinotecan and SN-38 pharmacokinetics and carboxylesterase expression in knockout and humanized transgenic mice.
Molecular cancer therapeutics 13, 492-503 [PubMed:24194565]
[show Abstract]
Organic anion-transporting polypeptides (OATP) mediate the hepatic uptake of many drugs, thus codetermining their clearance. Impaired hepatic clearance due to low-activity polymorphisms in human OATP1B1 may increase systemic exposure to SN-38, the active and toxic metabolite of the anticancer prodrug irinotecan. We investigated the pharmacokinetics and toxicity of irinotecan and SN-38 in Oatp1a/1b-null mice: Plasma exposure of irinotecan and SN-38 was increased 2 to 3-fold after irinotecan dosing (10 mg/kg, i.v.) compared with wild-type mice. Also, liver-to-plasma ratios were significantly reduced, suggesting impaired hepatic uptake of both compounds. After 6 daily doses of irinotecan, Oatp1a/1b-null mice suffered from increased toxicity. However, Oatp1a/1b-null mice had increased levels of carboxylesterase (Ces) enzymes, which caused higher conversion of irinotecan to SN-38 in plasma, potentially complicating pharmacokinetic analyses. Ces inhibitors blocked this increased conversion. Interestingly, liver-specific humanized OATP1B1 and OATP1B3 transgenic mice had normalized hepatic expression of Ces1 genes. While irinotecan liver-to-plasma ratios in these humanized mice were similar to those in Oatp1a/1b-null mice, SN-38 liver-to-plasma ratios returned to wild-type levels, suggesting that human OATP1B proteins mediate SN-38, but not irinotecan uptake in vivo. Upon direct administration of SN-38 (1 mg/kg, i.v.), Oatp1a/1b-null mice had increased SN-38 plasma levels, lower liver concentrations, and decreased cumulative biliary excretion of SN-38. Mouse Oatp1a/1b transporters have a role in the plasma clearance of irinotecan and SN-38, whereas human OATP1B transporters may only affect SN-38 disposition. Oatp1a/1b-null mice have increased expression and activity of Ces1 enzymes, whereas humanized mice provide a rescue of this phenotype. | Fujita K, Sugiura T, Okumura H, Umeda S, Nakamichi N, Watanabe Y, Suzuki H, Sunakawa Y, Shimada K, Kawara K, Sasaki Y, Kato Y (2014)
Direct inhibition and down-regulation by uremic plasma components of hepatic uptake transporter for SN-38, an active metabolite of irinotecan, in humans.
Pharmaceutical research 31, 204-215 [PubMed:23921491]
[show Abstract]
PurposeClinical study has previously revealed that plasma concentration of 7-ethyl-10-hydroxycamptothecin (SN-38), an active metabolite of irinotecan, was higher in patients with end-stage renal failure than those with normal kidney function although SN-38 is mainly eliminated in the liver. Here, we focused on inhibition by uremic toxins of hepatic SN-38 uptake and down-regulation of uptake transporter(s) by uremic plasma in humans.MethodsWe evaluated SN-38 uptake and its inhibition by uremic toxins, 3-carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF), indoxyl sulfate (Indox), hippuric acid (HA) and indole acetate (IA), with cryopreserved human hepatocytes and HEK293 cells stably expressing hepatic uptake transporters, organic anion transporting polypeptides (OATPs). We also collected plasma samples from patients with severe renal failure to examine their effects on mRNA level of OATPs in primary cultured human hepatocytes.ResultsSN-38 was taken up by hepatocytes, which showed biphasic saturation patterns. The SN-38 uptake by hepatocytes was significantly inhibited by a uremic toxin mixture including clinically relevant concentrations of CMPF, Indox, HA and IA. Kinetic analyses for OATP-mediated transport revealed that the uptake of SN-38 by OATP1B1 was the highest, followed by OATP1B3. Among the uremic toxins, CMPF exhibited most potent inhibition of OATP1B1-mediated SN-38 uptake and directly inhibited the uptake of SN-38 also in hepatocytes. In addition, gene expression of OATP1B1 and OATP1B3 in hepatocytes was significantly down-regulated by the treatment with the uremic plasma.ConclusionsOATP1B1-mediated hepatic uptake of SN-38 was inhibited by uremic toxins, and gene expression of OATP1B1 was down-regulated by uremic plasma. | Yu J, Han JC, Gao YJ (2014)
Biotransformation of glucoaurantio-obtusin towards aurantio-obtusin increases the toxicity of irinotecan through increased inhibition towards SN-38 glucuronidation.
Phytotherapy research : PTR 28, 1577-1580 [PubMed:24842785]
[show Abstract]
The present study aims to investigate the influence of irinotecan's toxicity by the biotransformation of glucoaurantio-obtusin to aurantio-obtusin. Intraperitoneal administration (i.p.) of 100 mg/kg aurantio-obtusin significantly increased the toxicity of irinotecan, but the i.p. administration of 100 mg/kg glucoaurantio-obtusin showed negligible influence towards irinotecan's toxicity. Furthermore, the mechanism was explained through determining the inhibition potential of glucoaurantio-obtusin and aurantio-obtusin towards the glucuronidation metabolism of SN-38 that has been regarded to be the major active product responsible for the toxicity of irinotecan. The results showed that aurantio-obtusin exhibited strong competitive inhibition towards the glucuronidation of SN-38, but negligible inhibition potential of glucoaurantio-obtusin towards SN-38 glucuronidation was observed. These results showed that biotransformation of glucoaurantio-obtusin towards aurantio-obtusin increased the toxicity of irinotecan through increased inhibition of SN-38 glucuronidation. | Yang FY, Zhang WP, Wang XY, Yang WC, Dang HW (2014)
[Pharmacokinetics of SN-38 in rats and tissue distribution of 7-ethyl-10-hydroxycamptothecin in mice after intravenous injection of irinotecan hydrochloride nanoparticles].
Yao xue xue bao = Acta pharmaceutica Sinica 49, 1029-1033 [PubMed:25233635]
[show Abstract]
The paper reported an investigation of the pharmacokinetics of SN-38 (7-ethyl-10-hydroxy-camptothecin) in rats and the tissue distribution in mice after injection of irinotecan hydrochloride nanoparticles (CPT-11) via tail veins. An LC-MS/MS method was established to determine the concentrations of SN-38 in whole blood of rats and in different tissues of mice. The pharmacokinetics and tissue distribution of SN-38 were compared after the intravenous injection of CPT-11 NPs and CPT-11 solution. Compared with irinotecan solution, the elimination half-life of SN-38 was prolonged from 2.17 h to 2.67 h after the intravenous injection of CPT-11 NPs, but its AUC had little change. After the injection of CPT-11 NPs in mice, over time, the concentrations of CPT-11-metabolized SN-38 in CPT-11 NPs were significantly higher in the whole blood, colon and lungs than those in CPT-11 solution, followed by in the spleen and liver, but those in the heart and brain had no change. However, the amount of SN-38 in the kidneys was reduced with time. CPT-11 NPs could prolong SN-38's (one of its metabolites) blood circulation time in rats and significantly increased the concentration of CPT-11-metabolized SN-38 in the whole blood, colon and lungs of mice. CPT-11 NPs made SN-38 efficiently target-bind to the colon and lungs of mice. |
|
