Abstract 5883: CHD1 as regulator of cell adhesion in Ets fusion negative prostate cancer

Abstract

Prostate cancer (PCa) develops into lethal disease in about 10% of men diagnosed with this malignancy. Common genomic changes are seen in PCa such as alterations in CDKN1B, RB1, TP53, PTEN, NKX3-1, MYC and androgen receptor. Oncogenic fusions involving the Ets family are seen in 50-70% PCa patients, the most common of which is TMPRSS2-ERG. TMPRSS2-ERG influences cell migration, particularly when PTEN is co-deleted or PIK3CA activating mutations are present. However, in the absence of ERG fusions, molecular drivers of the PCa phenotype are less clear but include alterations in SPOP (6-15% of PCa), SPINK1 (10%), MAP3K7 (18-38%) and CHD1 (15-27%). CHD1 (Chromo-domain Helicase DNA Binding Protein-1) is a chromatin remodeling factor with many roles including homologous recombination mediated DNA repair of double strand breaks and maintenance of genomic stability and therefore it is hypothesized to cause the predominant intrachromosomal rearrangements observed in Ets fusion negative tumors. This study was undertaken to evaluate the cellular effects that follow CHD1 deletion that could aid PCa initiation and progression. CHD1 was knocked out in the non tumorigenic, HPV16 immortalised prostate epithelial cell line, RWPE-1, using CRISPR/Cas9. Compared to parental RWPE-1 and non target cells (NT2), the CHD1 KO cells had a smaller and rounder morphology and were less adherent to tissue culture plates. To study expression of extracellular matrix and adhesion molecules, RT profiler assay was performed using RWPE-1 parental and CHD1 KO cells. CHD1 KO cells showed a decrease in the expression of SPARC, MMP2, ITGA2, ITGA5, ITGA6, FN1, LAMB3, collagen, tenascin and vitronectin as compared to parentals and NT2. Reduction in extracellular matrix and adhesion molecules and altered morphology of CHD1 KO cells as compared to parentals and NT2 cells suggest that loss of CHD1 reduces cell-cell and cell-matrix adhesion. These results suggest that in the absence of PTEN loss in Ets negative tumors, deletion of CHD1 gene could change cell adhesion dynamics ascribing a new role for CHD1 in the development and progression of PCa. Citation Format: Aparna Kareddula, Whitney Petrosky, Irina Tereshchenko, Daniel Medina, Hana Aviv, Eric Singer, Robert S. DiPaola, Kim M. Hirshfield. CHD1 as regulator of cell adhesion in Ets fusion negative prostate 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 5883. doi:10.1158/1538-7445.AM2017-5883