Ontology highlight
ABSTRACT: Background
Small cell lung cancer (SCLC) is a deadly neuroendocrine tumor with limited therapeutic options. Recent data suggest that histone deacetylases (HDACs) and the phosphatidylinositol 3-kinase (PI3K) pathway play essential roles in SCLC cell proliferation and survival.Methods
The inhibition of the PI3K signaling and HDAC activity by CUDC-907 was analyzed by western blotting. The effect of CUDC-907 on olaparib-induced DNA damage response was assessed by western blotting and Immunofluorescence staining. The cytotoxicity of CUDC-907 alone or in combination with olaparib in a panel of SCLC cell lines were evaluated by the CellTiter-Glo Luminescent Cell Viability Assay and flow cytometry. The in vivo effects of CUDC-907 and olaparib alone or in combination were examined using a patient-derived xenografts (PDX) model of SCLC.Results
CUDC-907 treatment downregulated MYC paralogs and FoxM1, induced G1 cell-cycle arrest, and impaired DNA double-strand break (DSB) repair capacity in SCLC cells, which produced a potent antiproliferative effect. Furthermore, we showed that CUDC-907 treatment enhanced the therapeutic efficacy of PARP inhibitor olaparib in SCLC cellular models and a PDX model. Mechanistic investigations demonstrated that CUDC-907 synergized with olaparib through the blockade of DSB repair pathways and downregulation of MYC paralogs and FoxM1.Conclusions
Our study uncovers that dual PI3K and HDAC inhibition by CUDC-907 exerts significant single-agent activity and strong synergistic effects with PARP inhibitor olaparib in SCLC, which thus provides a rational combination treatment strategy for SCLC clinical investigation.
SUBMITTER: Ma L
PROVIDER: S-EPMC7568419 | biostudies-literature | 2020 Oct
REPOSITORIES: biostudies-literature
Ma Liying L Bian Xing X Lin Wenchu W
Journal of experimental & clinical cancer research : CR 20201017 1
<h4>Background</h4>Small cell lung cancer (SCLC) is a deadly neuroendocrine tumor with limited therapeutic options. Recent data suggest that histone deacetylases (HDACs) and the phosphatidylinositol 3-kinase (PI3K) pathway play essential roles in SCLC cell proliferation and survival.<h4>Methods</h4>The inhibition of the PI3K signaling and HDAC activity by CUDC-907 was analyzed by western blotting. The effect of CUDC-907 on olaparib-induced DNA damage response was assessed by western blotting and ...[more]