Abstract 4786: Integrated eoxme and transcriptome sequencing identifies a novel candidate for breast cancer

Abstract

Abstract Many somatic mutations, structural alterations, and gene expression changes are causally implicated in oncogenesis and tumor progression, and as a result, affect clinical outcome. Although majority of breast cancer patients have benefits from therapeutics targeting tumor biology still many patients suffer from disease recurrence and metastasis. To find novel therapeutic target in breast cancer, here we examine the both whole exome and whole transcriptome of fresh-frozen primary breast cancer tissues from 120 patients whose clinical, pathological, and survival data are available. We identified 11,684 putative somatic mutations in 7,373 genes. We hypothesized that therapeutic target has to have recurrent mutation and gene expression at least more than average expression. With a cut-off of 3 or more mutations in each gene, 1,116 genes were selected. After the filtering of Volume>0.3, 696 genes were selected. Finally, 55 genes were selected which are druggable or potentially druggable using drug database. Interestingly, 18 of the 55 were genes involved in metabolism. Among them we further focused PSMD2 and interrogated their oncogenic roles, a subunit of the 19S regulatory complex of proteasomes, as a constituent of a signature is a candidate driven factor in breast cancer. PSMD2 is required for proliferation both in vitro and in vivo, as shRNA-mediated PSMD2 silencing attenuated tumor growth. Further, PMSD2 is sufficient to induce stem cell characteristics, as forced PSMD2 expression facilitated mammosphere formation and increased the CD44+ breast CSC-like population. Mechanistically, PSMD2 inhibition were associated with changes in epithelial-mesenchymal transition (EMT) phenotype. Knockdown of PSMD2 induced dramatic morphological changes, the typical spindle-like appearance cells were replaced with the round shape, like epithelial morphology. Moreover, treatment of TGF-β1, the main inducer of EMT, lead to increased expression of PSMD2. PSMD2 silencing up-regulated E-cadherin and down-regulated expression of vimentin, N-cadherin and snail, mesenchymal markers. Clinically, PSMD2 expression was elevated in basal-like TNBC (triple negative breast cancer), correlated with poor prognosis, insilico analysis on a dataset comprising over 2413 microarrays of the web application bc-GenExMiner. Altogether, our findings suggest that PSMD2 may be a good molecular target candidate and PSMD2 inhibitor may kills breast cancer stem cells and ameliorates poor prognosis of breast cancer. Citation Format: Kyung-Min Lee, Dong-Young Noh, Wonshik Han. Integrated eoxme and transcriptome sequencing identifies a novel candidate for breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4786. doi:10.1158/1538-7445.AM2017-4786