Targeting phospho-MARCKS overcomes drug-resistance and induces antitumor activity in preclinical models of multiple myeloma

Y Yang; Y Chen; M N Saha; J Chen; K Evans; L Qiu; D Reece; G A Chen; H Chang

doi:10.1038/leu.2014.255

Targeting phospho-MARCKS overcomes drug-resistance and induces antitumor activity in preclinical models of multiple myeloma

Leukemia. 2015 Mar;29(3):715-26. doi: 10.1038/leu.2014.255. Epub 2014 Sep 2.

Authors

Y Yang¹, Y Chen², M N Saha¹, J Chen³, K Evans³, L Qiu⁴, D Reece⁵, G A Chen⁶, H Chang⁷

Affiliations

¹ 1] Division of Molecular and Cellular Biology, Toronto General Research Institute, Toronto, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.
² 1] Division of Molecular and Cellular Biology, Toronto General Research Institute, Toronto, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada [3] Department of Hematology/Oncology, First Affiliated Hospital, Nanchang University, Nanchang, China.
³ Ontario Cancer Biomarker Network, Toronto, Canada.
⁴ Department of Lymphoma & Myeloma, Institute of Hematology & Blood Diseases Hospital, State Key Laboratory of Experimental Hematology, Chinese Academy of Medical Sciences & Peking Union of Medical College, Tianjin, People's Republic of China.
⁵ Department of Laboratory Hematology and Medical Oncology, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
⁶ Department of Hematology/Oncology, First Affiliated Hospital, Nanchang University, Nanchang, China.
⁷ 1] Division of Molecular and Cellular Biology, Toronto General Research Institute, Toronto, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada [3] Department of Hematology/Oncology, First Affiliated Hospital, Nanchang University, Nanchang, China [4] Department of Laboratory Hematology and Medical Oncology, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.

PMID: 25179733
DOI: 10.1038/leu.2014.255

Abstract

Multiple myeloma (MM) is incurable in virtually all patients due to the presence of innate and emergent drug-resistance. To identify potential drug resistance mechanisms in MM we used iTRAQ (isobaric tags for relative and absolute quantitation) mass spectrometry to compare protein expression profiles of drug-resistant (RPMI 8226-R5) and sensitive (RPMI 8226-S) isogenic cell lines. We identified selective overexpression of myristoylated alanine-rich C-kinase substrate (MARCKS) in drug-resistant R5 cells. MARCKS overexpression was also observed in several drug-resistant human myeloma cell lines (HMCLs) and in drug-resistant primary MM samples. Functionally, inhibition of MARCKS phosphorylation by enzastaurin or knockdown of the gene by RNAi significantly enhanced the sensitivity of resistant HMCLs and primary MM samples to bortezomib and to other anti-myeloma drugs, providing evidence that MARCKS can modulate drug response. Mechanistically, pMARCKS (phosphorylated form of MARCKS) was found to function as an E2F-1 cofactor to regulate SKP2 transcription. pMARCKS promoted cell-cycle progression by facilitating SKP2 expression, suppressing p27(Kip1) and potentially counteracting drug-induced cell-cycle arrest by promoting Cyclin E/CDK2 activity. Importantly, MARCKS knockdown in combination with bortezomib treatment overcame bortezomib resistance, significantly inhibited tumor growth and prolonged host survival in a MM xenograft model. These data provide a rationale for therapeutic targeting of pMARCKS to improve the outcome of patients with refractory/relapsed MM.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antineoplastic Agents / pharmacology*
Boronic Acids / pharmacology*
Bortezomib
Cell Cycle / drug effects
Cell Line, Tumor
Cyclin E / genetics
Cyclin E / metabolism
Cyclin-Dependent Kinase 2 / genetics
Cyclin-Dependent Kinase 2 / metabolism
Cyclin-Dependent Kinase Inhibitor p27 / genetics
Cyclin-Dependent Kinase Inhibitor p27 / metabolism
Disease Models, Animal
Drug Resistance, Neoplasm / drug effects
Drug Resistance, Neoplasm / genetics
E2F1 Transcription Factor / genetics
E2F1 Transcription Factor / metabolism
Gene Expression Regulation, Neoplastic*
Humans
Indoles / pharmacology
Intracellular Signaling Peptides and Proteins / genetics*
Intracellular Signaling Peptides and Proteins / metabolism
Membrane Proteins / genetics*
Membrane Proteins / metabolism
Mice
Multiple Myeloma / drug therapy*
Multiple Myeloma / genetics*
Multiple Myeloma / mortality
Multiple Myeloma / pathology
Myristoylated Alanine-Rich C Kinase Substrate
Neoplasm Transplantation
Phosphorylation
Primary Cell Culture
Pyrazines / pharmacology*
RNA, Small Interfering / genetics
RNA, Small Interfering / metabolism
S-Phase Kinase-Associated Proteins / genetics
S-Phase Kinase-Associated Proteins / metabolism
Signal Transduction
Survival Analysis

Substances

Antineoplastic Agents
Boronic Acids
Cdkn1b protein, mouse
Cyclin E
E2F1 Transcription Factor
E2f1 protein, mouse
Indoles
Intracellular Signaling Peptides and Proteins
MARCKS protein, human
Marcks protein, mouse
Membrane Proteins
Pyrazines
RNA, Small Interfering
S-Phase Kinase-Associated Proteins
Myristoylated Alanine-Rich C Kinase Substrate
Cyclin-Dependent Kinase Inhibitor p27
Bortezomib
Cdk2 protein, mouse
Cyclin-Dependent Kinase 2
enzastaurin