Figure 1. PKM2 is essential for proliferation/transformation and is highly phosphorylated at Y105 in breast cancer cells. A).

Kaplan-Meier survival curves of 3951 breast cancer patients whose tumors had a high or low PKM2 expression (DOI: 10.18632/oncotarget.10337). B) Left: Western blot analysis of PKM2 expression in MDA-MB-231 cells transfected with control shRNA (shCtrl) or two different shRNAs against PKM2 (shPKM2-1, and shPKM2-2); Right: the growth curves of the indicated MDA-MB-231 sublines by MTT assays. “***” means P<0.001. C) Left: Western blot analysis of PKM2 expression in MCF10A cells transfected with shCtrl, shPKM2-1, or shPKM2-2; Right: the growth curves of the indicated MCF10A sublines by MTT assays. “n.s” means not statistically significant. D) Representative images (left) and quantification (right) of colony formation in soft agar from the PKM2 shRNA knockdown MDA-MB-231 sublines. E) Western blot analysis using PKM2 antibodies to detect PKM2 tetramers and dimers in non-transformed mammary epithelial cell lines (MCF-12A and MCF-10A) and in triple-negative breast cancer cell lines (MDA-MB-231 and MDA-MB-435). F) Western blot analysis of pY105-PKM2 and total PKM2 protein levels in the indicated non-transformed mammary epithelial cell lines vs luminal and basal type breast cancer cell lines. Quantification of pY105-PKM2 level in different cell lines compared to that in MCF10A (normalized to β-actin) is conducted by Image J software. G) Left: Representative IHC staining of pY105-PKM2 and total PKM2 proteins in human normal breast tissues versus in human invasive breast cancer samples. Right: Quantification of the immunoreactive score (IRS) of pY105 PKM2 and total PKM2 IHC staining in mammary epithelial cells of normal human breast and breast cancer samples (n=5 in each group). “***” means P<0.001. “n.s” means not statistically significant.