Proliferating effect of orotic acid through mTORC1 activation mediated by negative regulation of AMPK in SK-Hep1 hepatocellular carcinoma cells.

Eun-Jeong Jung, Kang-Yo Lee, Byung-Hoon Lee

College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Korea.

The Journal of toxicological sciences 2012

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Orotic acid (OA) is a tumor promoter of experimental liver carcinogenesis initiated by DNA reactive carcinogens, the molecular mechanisms of which have not been fully elucidated. OA increases cell proliferation and decreases apoptosis in serum-starved SK-Hep1 hepatocellular carcinoma cells, which may ascribe to the inhibition of AMP-activated protein kinase (AMPK) phosphorylation and thus activation of mammalian target of rapamycin complex 1 (mTORC1). The effects of OA on mTORC1 activation, cell proliferation, and cell-cycle progression to S and G2/M phases were completely reversed by rapamycin. Activation of AMPK by a constitutively active mutant or aminoimidazole carboxamide ribonucleotide (AICAR) rescued the effects of OA. In conclusion, OA increases the proliferation and decreases the starvation-induced apoptosis of SK-Hep1 cells via mTORC1 activation mediated by negative regulation of AMPK.

Citation

Eun-Jeong Jung, Kang-Yo Lee, Byung-Hoon Lee. Proliferating effect of orotic acid through mTORC1 activation mediated by negative regulation of AMPK in SK-Hep1 hepatocellular carcinoma cells. The Journal of toxicological sciences. 2012;37(4):813-21