PKM2 enhances cancer invasion via ETS-1-dependent induction of matrix metalloproteinase in oral squamous cell carcinoma cells

OBJECTIVES: This study aimed at investigating the molecular mechanism underlying PKM2-mediated cancer invasion. MATERIALS & METHODS: To optimize the investigation of PKM2-specific effects, we used two immortalized oral cell lines. The two cell lines drastically differed in PKM2 expression level, particularly in the level of nuclear PKM2, and subsequently in glucose metabolism and tumorigenicity. RESULTS: Knockdown of PKM2 reduced not only the glucose metabolism but also the invasive activity by curtailing the expressions of matrix metalloproteinases (MMP): PKM2 could modulate MMP-9 expression by regulating ETS-1 inside the nucleus. These results were further confirmed in an oral squamous cell carcinoma (OSCC) cell line. In correspondence with in vitro findings, clinicopathological data from OSCC patients indicated strong association between PKM2 expression and poor survival rate. Additionally, upon analysis of public database, significant positive correlation was found between PKM2 and ETS-1 in OSCC. CONCLUSION: Collectively, this study unveiled the molecular mechanism underlying PKM2-mediated cancer invasion, thereby providing novel targets for therapeutics development against invasive OSCC.