A novel HMGA2/MPC-1/mTOR signaling pathway promotes cell growth via facilitating Cr (VI)-induced glycolysis.

ABSTRACT

Mitochondrial Pyruvate Carrier 1 (MPC1) is localized on mitochondrial outer membrane to mediate the transport of pyruvate from cytosol to mitochondria. It is also well known to act as a tumor suppressor. Hexavalent chromium (Cr (VI)) contamination poses a global challenge due to its high toxicity and carcinogenesis. This research was intended to probe the potential mechanism of MPC1 in the effect of Cr (VI)-induced carcinogenesis. First, Cr (VI)-treatments decreased the expression of MPC1 in vitro and in vivo. Overexpression of MPC1 inhibited Cr (VI)-induced glycolysis and migration in A549 cells. Then, high mobility group A2 (HMGA2) protein strongly suppressed the transcription of MPC1 by binding to its promoter, and HMGA2/MPC1 axis played an important role in oxidative phosphorylation (OXPHOS), glycolysis and cell migration. Furthermore, endoplasmic reticulum (ER) stress made a great effect on the interaction between HMGA2 and MPC1. Finally, the mammalian target of the rapamycin (mTOR) was determined to mediate MPC1-regulated OXPHOS, aerobic glycolysis and cell migration. Collectively, our data revealed a novel HMGA2/MPC-1/mTOR signaling pathway to promote cell growth via facilitating the metabolism reprogramming from OXPHOS to aerobic glycolysis, which might be a potential therapy for cancers.