Abstract 521: Connexin 43 and E-cadherin modulate prostate cancer cell migration

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Connexins play a major role in cell-cell communication and form a bidirectional signaling pathway to assemble gap junctions and, along with cadherins, alter cell behaviors, such as motility. To assess the effect of Connexin 43 (Cx43) on migration of prostate cancer cells we performed two types of migration assays using shRNA Cx43 transfected PC3 cells with suppressed Cx 43. Wound healing and transwell chamber assays were used to assess the migratory potential of stably transfected shCx43-PC3 cells. When we reduced Cx 43 we saw approximately a two-fold reduction in migration of shCx43 transfected PC3 cells compared to those transfected with scramble controls. Since suppression of Cx43 reduced migration of the highly migratory PC3 cells, we wondered whether this reflected a partial loss of mesenchymal traits (e.g., motility) and acquisition of epithelial markers, (e.g.,E-cadherin expression). Using quantitative RT-PCR, E-cadherin expression was assessed in shCx43-PC3 and scramble control cells. Suppression of Cx43 increased E-cadherin mRNA levels 5-fold or greater in shCx43-PC3 cells than in scramble control cells. An alternative approach used to transcriptionally up-regulate E-cadherin mRNA in PC3 cells (via suppression of a transcriptional repressor) resulted in a similar approximately 2.5-fold suppression of migration as measured by wound healing and transwell chamber assays. Thus, an inverse relation of Cx 43 and E-cadherin was observed in prostate cancer cells and alterations in either led to aberrant migration. These results were consistent with our hypothesis that differential connexin expression in prostate cancer cells contributes to different metastatic potential. To correlate differential connexin subunit expression with migratory potential, we quantified gene expression of 13 different Connexin subunits in non-invasive LNCaP and in invasive PC3 cells using qRTPCR. In LNCaP cells we observed low levels of Cx43 along with high levels of Cx32 and E-cadherin expression and the converse in PC3 cells. Overall, these results suggest that reducing high levels of Cx43, associated with enhanced E-cadherin expression and reduced migratory behavior could potentially block lethal metastatic tumor progression of prostate cancer cells. Citation Format: Abdulaziz Aloliqi, Ao Zhang, Adina Brett-Morris, Justin Lathia, Gail C. Fraizer. Connexin 43 and E-cadherin modulate prostate cancer cell migration. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 521. doi:10.1158/1538-7445.AM2015-521