00085472can100944-sup-sfigs_1-2.pdf (926.29 kB)
Supplementary Figures 1-2 from Tumor Cell Kill by c-MYC Depletion: Role of MYC-Regulated Genes that Control DNA Double-Strand Break Repair
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posted on 2023-03-30, 19:45 authored by Kaisa R. Luoto, Alice X. Meng, Amanda R. Wasylishen, Helen Zhao, Carla L. Coackley, Linda Z. Penn, Robert G. BristowSupplementary Figures 1-2 from Tumor Cell Kill by c-MYC Depletion: Role of MYC-Regulated Genes that Control DNA Double-Strand Break Repair
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ARTICLE ABSTRACT
MYC regulates a myriad of genes controlling cell proliferation, metabolism, differentiation, and apoptosis. MYC also controls the expression of DNA double-strand break (DSB) repair genes and therefore may be a potential target for anticancer therapy to sensitize cancer cells to DNA damage or prevent genetic instability. In this report, we studied whether MYC binds to DSB repair gene promoters and modulates cell survival in response to DNA-damaging agents. Chromatin immunoprecipitation studies showed that MYC associates with several DSB repair gene promoters including Rad51, Rad51B, Rad51C, XRCC2, Rad50, BRCA1, BRCA2, DNA-PKcs, XRCC4, Ku70, and DNA ligase IV. Endogenous MYC protein expression was associated with increased RAD51 and KU70 protein expression of a panel of cancer cell lines of varying histopathology. Induction of MYC in G0-G1 and S-G2-M cells resulted in upregulation of Rad51 gene expression. MYC knockdown using small interfering RNA (siRNA) led to decreased RAD51 expression but minimal effects on homologous recombination based on a flow cytometry direct repeat green fluorescent protein assay. siRNA to MYC resulted in tumor cell kill in DU145 and H1299 cell lines in a manner independent of apoptosis. However, MYC-dependent changes in DSB repair protein expression were not sufficient to sensitize cells to mitomycin C or ionizing radiation, two agents selectively toxic to DSB repair–deficient cells. Our results suggest that anti-MYC agents may target cells to prevent genetic instability but would not lead to differential radiosensitization or chemosensitization. Cancer Res; 70(21); 8748–59. ©2010 AACR.Usage metrics
Keywords
Biological Agents & TherapiesAntisense oligonucleotidesChemotherapyCombination chemotherapyDrug MechanismsModulation of DNA repairGene RegulationInducible gene expressionPromoter/enhancer analysisGenitourinary CancersProstate cancerGenome BiologyRadiation OncologyModification of radiation sensitivityRadiobiology