Abstract
The ecdysone-inducible mammalian expression system is frequently used for inducible transgene expression in vitro and in vivo. Here, we describe a strong antiapoptotic effect of ecdysone analogs in the human colon carcinoma cell line RKO, which is in contrast to published data that ecdysteroids do not influence mammalian cell physiology. Inhibition of Fas ligand- and TNF-related apoptosis-inducing ligand-induced apoptosis by muristerone A occurs at the level of caspase-8 activation and is neutralized by phosphatidylinositol-3-kinase/Akt, protein kinase C and mitogen-activated protein kinase inhibitors. Microarray, Northern and Western blot analysis revealed that incubation of RKO cells with muristerone A leads to changes in gene expression levels, including an upregulation of bcl-x(L) mRNA and protein levels. Our data imply that ecdysteroids and ecdysone mimics can induce and/or repress gene transcription in RKO and other mammalian cells, thereby influencing the apoptotic behavior. Therefore, the ecdysone-inducible mammalian expression system may not be suitable for the analysis of apoptosis-related genes.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Androstadienes / pharmacology
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Apoptosis / drug effects*
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Apoptosis / genetics
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Apoptosis Regulatory Proteins / pharmacology*
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Caspase 8
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Caspases / metabolism
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Cell Cycle / drug effects
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Cell Cycle / physiology
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Cell Line, Tumor
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Chromones / pharmacology
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Colonic Neoplasms / chemistry
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Colonic Neoplasms / genetics
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Colonic Neoplasms / pathology*
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Ecdysterone / analogs & derivatives*
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Ecdysterone / pharmacology
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Enzyme Activation / drug effects
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Fas Ligand Protein
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Flavonoids / pharmacology
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Gene Expression Regulation, Neoplastic / drug effects*
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Humans
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Membrane Glycoproteins / pharmacology*
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Morpholines / pharmacology
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Oncogene Protein v-akt / metabolism
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Phosphatidylinositol 3-Kinases / metabolism
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Proliferating Cell Nuclear Antigen / analysis
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Proliferating Cell Nuclear Antigen / genetics
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Protein Kinase C / antagonists & inhibitors
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RNA, Messenger / analysis
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Recombinant Proteins / pharmacology
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Signal Transduction / drug effects
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TNF-Related Apoptosis-Inducing Ligand
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Tumor Necrosis Factor-alpha / pharmacology*
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Tumor Necrosis Factors / pharmacology*
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Wortmannin
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bcl-X Protein / genetics
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bcl-X Protein / metabolism
Substances
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Androstadienes
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Apoptosis Regulatory Proteins
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Chromones
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FASLG protein, human
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Fas Ligand Protein
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Flavonoids
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Membrane Glycoproteins
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Morpholines
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Proliferating Cell Nuclear Antigen
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RNA, Messenger
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Recombinant Proteins
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TNF-Related Apoptosis-Inducing Ligand
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TNFSF10 protein, human
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Tumor Necrosis Factor-alpha
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Tumor Necrosis Factors
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bcl-X Protein
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p27 antigen
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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muristerone A
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Ecdysterone
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ponasterone A
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Phosphatidylinositol 3-Kinases
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Oncogene Protein v-akt
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Protein Kinase C
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CASP8 protein, human
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Caspase 8
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Caspases
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2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one
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Wortmannin