Abstract 1090: The role of connexin43 in prostate cancer motility

Abstract

Abstract Prostate cancer (PC) is one of the most common male cancers in United States. PC lethality is due to metastatic growth, when cancer cells move from the primary tumor site to a secondary site. A key step in metastsis is the acquisition of motility. Connexins (Cx) play a major role in cell-cell communication and growing evidence demonstrates their contribution to cell motility. Cx43 is up-regulated in cultured PC3 metastatic prostate cancer cells. To understand the role of Cx43 in migration we asked whether silencing Cx43 would decrease PC3 cell migration. Using cells in which short interfering RNA (sh-RNA) silenced Cx43 mRNA, we showed that silencing Cx43 decreased motility of sh-Cx43 PC3 cells in Boyden chamber assays. To confirm these results in another biological system, we performed cellular wound healing assays. Silencing Cx43 decreased motility of PC3 cells reducing movement to wounded area, leaving more area open in the Cx43 inhibited cell lines. The wound healing assay showed that knockdown Cx43 altered directional movement, velocity and distance. These results supported those of our Boyden assays showing that loss of Cx43 decreases the migratory ability of PC3. Conversely, the overexpression of Cx43 in LNCaP cells, non-migratory prostate cancer cells that lack Cx43 expression, increased their motility. A comparison of cell lines engineered to overexpress or to silence Cx43 confirms the importance of Cx43 in the motility of prostate cancer cells in vitro. Although the mechanism whereby Cx43 regulates motility is still unclear, our preliminary data revealed that Cx43 co-immunoprecipitated with N-cadherin, suggesting that they form a complex in PC3 cells. Cell fractionation studies of PC3 control cells showed that N-cadherin was located in the cell membrane and not detected free in the cytoplasm, but in sh-Cx43 PC3 cells that lack Cx43, the distribution of N-cadherin protein was altered and significant levels of N-cadherin were also detected in cytoplasmic fractions. Whether changes in N-cadherin distribution is a direct or indirect result of loss of Cx43 in sh-Cx43 PC3 cells, is unclear. However, modulation of Cx43 levels in prostate cancer cells does alter motility and N-cadherin distribution. These results indicate that Cx43 and N-cadherin are in close association in PC3 cells and their interaction may play an important role in prostate cancer cell motility. A better understanding of the requirements of migratory PC cells may lead to more effective targeting of key steps in PC progression to lethal metastatic disease. Citation Format: Abdulaziz A. Aloliqi. The role of connexin43 in prostate cancer motility [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1090.