👤 Elaine Barrie

Identifying cytogenetic changes in tumors can aid in diagnosis/prognosis and disease management. Complete cytogenetic characterization has historically required a multimethod/time-consuming approach. Optical genome mapping (OGM) offers a potential solution to this challenge by detecting both balanced and unbalanced abnormalities in a single assay. Genetic changes acquired with tumor-forming potential in a prostate xenograft subline [M2205] (derived from a Black male) that were detected using cytogenetic versus OGM analyses were compared to assess the utility of OGM for analyzing solid tumors. Cytogenetic/OGM concordance was noted for (a) copy number gains (16, 1p, 3q, 5q, 7p, 8q, 9q, 11p, 11q, 15q, 20q), (b) copy number losses (Y, 3p, 4p, 6p, 7p, 9p, 11q), and (c) structural changes, including multibreak rearrangements. Discordance was noted for two structural findings, both of which had breakpoints localized to repetitive sequences. The OGM studies identified new findings and confirmed/further characterized 8q24 structural abnormalities. It also detected genes gained/disrupted in the 8q24 region (e.g., MYC, DEPTOR, and EXT1); but recognizing a jumping translocation required cytogenetic analyses. These results support using OGM as a tool to analyze solid tumors in clinical/research settings. Moreover, this OGM analysis expanded the characterization of cytogenetic changes present in the M2205 subline, including alterations associated with tumors from Black males diagnosed with prostate cancer. Show less

Deregulation of the cyclin-dependent kinases (CDKs) has been implicated in the pathogenesis of multiple cancer types. Consequently, CDKs have garnered intense interest as therapeutic targets for the treatment of cancer. We describe herein the molecular and cellular effects of CCT068127, a novel inhibitor of CDK2 and CDK9. Optimized from the purine template of seliciclib, CCT068127 exhibits greater potency and selectivity against purified CDK2 and CDK9 and superior antiproliferative activity against human colon cancer and melanoma cell lines. X-ray crystallography studies reveal that hydrogen bonding with the DFG motif of CDK2 is the likely mechanism of greater enzymatic potency. Commensurate with inhibition of CDK activity, CCT068127 treatment results in decreased retinoblastoma protein (RB) phosphorylation, reduced phosphorylation of RNA polymerase II, and induction of cell cycle arrest and apoptosis. The transcriptional signature of CCT068127 shows greatest similarity to other small-molecule CDK and also HDAC inhibitors. CCT068127 caused a dramatic loss in expression of DUSP6 phosphatase, alongside elevated ERK phosphorylation and activation of MAPK pathway target genes. MCL1 protein levels are rapidly decreased by CCT068127 treatment and this associates with synergistic antiproliferative activity after combined treatment with CCT068127 and ABT263, a BCL2 family inhibitor. These findings support the rational combination of this series of CDK2/9 inhibitors and BCL2 family inhibitors for the treatment of human cancer. Show less