Nuclear PKM2 regulates β-catenin transactivation upon EGFR activation

Abstract

SUMMARYThe embryonic pyruvate kinase M2 (PKM2) isoform is highly expressed in human cancer. In contrast to the established role of PKM2 in aerobic glycolysis or the Warburg effect 1,2,3 , its nonmetabolic functions remain elusive. Here we demonstrate that EGFR activation induces translocation of PKM2, but not PKM1, into the nucleus, where K433 of PKM2 binds to c-Srcphosphorylated Y333 of β-catenin. This interaction is required for both proteins to be recruited to the CCND1 promoter, leading to HDAC3 removal from the promoter, histone H3 acetylation, and cyclin D1 expression. PKM2-dependent β-catenin transactivation is instrumental in EGFRpromoted tumor cell proliferation and brain tumor development. In addition, positive correlations have been identified among c-Src activity, β-catenin Y333 phosphorylation, and PKM2 nuclear accumulation in human glioblastoma specimens. Furthermore, levels of β-catenin phosphorylation and nuclear PKM2 have been correlated with grades of glioma malignancy and prognosis. These findings reveal that EGF induces β-catenin transactivation via a mechanism distinct from that induced by Wnt/wingless 4 and highlight the essential nonmetabolic functions of PKM2 in EGFRpromoted β-catenin transactivation, cell proliferation, and tumorigenesis.Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms Correspondence: zhiminlu@mdanderson.org. Contributions This study was conceived by Z.L. Z.L and W.Y. designed the study; W.Y., Y.X., H.J., Y.Z., and J.L. performed experiments; K.A. provided pathology assistance; W.H. and X.G. provided reagents and conceptual advice; Z.L. wrote the paper with comments from all authors. Since both EGFR activation and PKM2 expression are instrumental in tumorigenesis 5,6,7 , we examined whether EGFR activation regulates PKM2 functions in a subcellular compartment-dependent manner. Immunofluorescence analysis showed that EGF treatment resulted in the nuclear accumulation of PKM2 in U87/EGFR human glioblastoma (GBM) cells (Fig. 1a). In addition, expression of the constitutively active EGFRvIII mutant in U87 cells had a higher amount of nuclear PKM2 than did EGF-untreated U87/EGFR cells ( Supplementary Fig. 2a). The finding that EGF induces nuclear translocation of PKM2 was further supported by cell fractionation analysis of DU145 prostate cancer cells, MDA-MB-231 breast cancer cells, and U87/EGFR cells ( Supplementary Fig. 2b). In addition, PKM1 failed to translocate into the nucleus upon EGF stimulation ( Supplementary Fig. 2c), indicating that EGF specifically regulates the subcellular distribution of PKM2 in multiple types of cancer cells. HHS Public AccessTo examine whether PKM2 directly regulates gene transcription and cell proliferation, we expressed PKM2 shRNA in U87/EGFR cells ( Supplementary Fig. 3a). PKM2 depletion largely reduced both basal and EGF-induced tumor cell prolife...

PKM2 Regulates Hepatocellular Carcinoma Cell Epithelial-mesenchymal Transition and Migration upon EGFR Activation

“…These events could in turn release β-catenin and into the cytoplasm and then into the nucleus, where it acts as a co-activator of T-cell and lymphoid enhancer factors (TCF/LEF) in the transcriptional activation of target genes (such as c-myc, snail-family members, cyclinD1 and Vimentin) involved in proliferation, invasion and tumor progression (Fang et al, 2007;Ji et al, 2009). Recent studies showed that EGF promoted glioblastoma cancer cell proliferation by increasing the expression of c-myc and cyclin D1, Which were regulated by the level of β-catenin phosphorylation at Tyr 333 residue (Yang et al, 2011). Our current results suggested that PI3K could phosphorylate β-catenin at Ser552 residue in a GSK3β-independent way upon EGFR activation, which upregulated the expression of snail and Vimentin, leading to HCC cell EMT and migration.…”

“…The results suggested that EGF up-regulated β-catenin transcriptional activity via a Wntindependent mechanism. Next, we asked whether EGF affected phosphorylation of β-catenin, which has been shown to be positively correlated with its nuclear translocation and independent of Wnt signaling (Fang et al, 2007;Yang et al, 2011). Interestingly, treatment with EGF for 24 h induced phosphorylation of β-catenin at Ser552 and Tyr 333 in a concentration-dependent manner in SMMC-7721 cells ( Figure 3C).…”

“…Several signaling pathways, including PI3K/AKT, mTOR, SRC, FAK, and ERK pathways, have been found to be involved in β-catenin-TCF-LEF transactivation (Fang et al, 2007;Ji et al, 2009;Yang et al, 2011). To define which pathway contributes to EGF-induced transcriptional activity of β-catenin, specific inhibitors of PI3K (LY294002), mTOR (rapamycin), SRC (SKI-1), FAK (Y15) and ERK (U0126) were utilized.…”

L’effet Warburg

“…Par exemple, les mutations activatrices de l'isocitrate déshydro-génase 1 dans des glioblastomes humains suggèrent que le contrôle métabolique est un élément clé de la carcinogenèse [3]. De même, PKM2 exerce un contrôle direct sur la progression du cycle cellulaire en activant la -caténine et participe ainsi à l'activation de la tumorigenèse induite par le facteur de croissance épidermique (EGF) [39]. Par ailleurs, les métabolites, tels que le NAD + et l'acétyl-CoA, produits en excès par une glycolyse accrue, influencent également l'activité d'enzymes responsables de modifications épigénétiques de la chromatine.…”

Metabolic Signature Genes Associated with Susceptibility to Pyruvate Kinase, Muscle Type 2 Gene Ablation in Cancer Cells

“…In contrast with the constitutively active PKM1, PKM2 is allosterically regulated either as a dimer with low affinity for PEP or as a tetramer with high affinity for PEP (Mazurek et al, 2005). The oncogenic signal-mediated allosteric change of PKM2 leads to accumulation of various glycolytic metabolites for macromolecular biosynthesis to support cell growth, providing a selective growth advantage for tumor cells (Christofk et al, 2008a;2008b;Hitosugi et al, 2009;Yang et al, 2011).…”