ZEB1 is regulated by PKCalpha in breast cancer cell lines

CABANILLAS, ANA M.; BARRIO-REAL, LAURA; VAGLIENTI, MARIA V.; LLORENS, M. CANDELARIA; KAZANIETZ, MARCELO; LOPEZ HABER, CYNTHIA

Washington, DC

Congreso; 110 Annual Meeting of the American Association of Cancer Research (AACR); 2017

Breast cancer is the second leading cause of cancer deaths in women. Cytokinesignals triggering kinase pathways play key roles in cancer progression whichregulate transcription factors such as ZEB1 or Snail. Our goal is to uncover therole of PKC signaling pathway in the regulation of the biological action of ZEB1.The protein expression of ZEB1,PKCisoforms, epithelial-to mesenchymal transition(EMT) markers were determined by Western Blotting (WB) in nine breastcancer cell lines. PKCa and ZEB1 had a signifıcant positive correlation(p0.05), and both proteins were highly expressed in mammary cell lines with amore aggressive phenotype (such as MDA-MB-231, BT-549 and MDA-MB-453). Interestingly, silencing PKCa using siRNAi signifıcantly reduced ZEB1expression in MDA-MB-231, MDA-MB-453 and BT-549 cells, as determined byWestern blot. Likewise, the pan-PKC inhibitor (GF109203) and the cPKC inhibitor(Gö6976) reduced ZEB1 expression in breast cancer cells. However, theEMT markers (E-cadherin, vimentin, ZO1 and N-cadherin) did not changetheir expression. ZEB1 mRNA levels did not change signifıcantly in PKCaknockdown cells, suggesting that PKC possibly regulates ZEB1 expression byaffecting its protein stability. In addition, we found that the motile and invasivecapacity of MDA-MB-231 cells was markedly affected in both PKCa and ZEB1knockdown cells. Interestingly, depletion of PKCa from MDA-MB-231 cellsmarkedly reduced the formation of ruffles and lamellipodia in response to serum,whereas ZEB1 depletion did not. In summary, our results revealed thatPKCa regulates the expression of the EMT marker ZEB1 in basal-like breastcancer cell lines, and that in addition PKCa is important for the control of cellinvasion and migration through regulation of ZEB1, thereby arguing that itcould be a potential target for breast cancer metastasis. Our results also suggestthat PKCa may control important phenotypic responses both through ZEB1-dependent and ZEB-independent mechanisms.