The phosphorylation of PCNA at Y211 and the cytotoxic effects of CPPP in normal breast cell line and TNBC cells.

<p>(A) Total cell lysate from MCF10A normal breast cell line or MDA-MB 468 and MDA-MB 231 TNBC cell lines were extracted, the protein levels of EGFR and total PCNA were determined by immunoblotting (IB). The Y211 phosphorylation of PCNA was examined by immunoprecipitation (IP) with anti-p-Y211 antibody and followed by IB against PCNA. (B) Each TNBC cell line was treated with indicated concentration of scrambled (Scramble) or Y211 CPPP (Y211F) peptides for 24 h. The relative cell viability was measured by WST-1 assay. (C) The percentage of the apoptotic cells from each TNBC cell line after 24 h treatment with 15 µM of Mock (PBS), Scramble and Y211F were determined by flow cytometry of Annexin V-positive cells. The bars indicate mean ± S.D. *, p<0.05; ***, p<0.001 by <i>t</i>-test.