Methylenetetrahydrofolate dehydrogenase 2 overexpression is associated with tumor aggressiveness and poor prognosis in hepatocellular carcinoma.

BACKGROUND: Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) is the key enzyme in the transformation of folic acid metabolites. MTHFD2 overexpression plays a key role in the progression of human cancers, and depletion of MTHFD2 has shown potential antitumor activities in several types of cancer. However, the role of MTHFD2 in hepatocellular carcinoma (HCC) has not been investigated. AIMS: To investigate the expression of MTHFD2 in HCC patients, and its associated clinical implications and possible functions in HCC. METHODS: Reverse transcription-polymerase chain reaction and immunohistochemical staining were used to detect MTHFD2 expression in liver tissues from HCC patients, then associations of MTHFD2 expression with demographic and clinicopathologic features were analysed. The effects of siRNA interference of MTHFD2 on cell proliferation, cell cycle, apoptosis, and migration were investigated in HCC cell lines. RESULTS: Significant overexpression of MTHFD2 was observed in HCC tissues, and overexpression of MTHFD2 was correlated with TNM stage, tumor microembolus, tumor metastasis, recurrence and the time of recurrence (P<0.05) in HCC patients. siRNA-mediated silencing of MTHFD2 inhibited migration, invasion and epithelial-mesenchymal transition progression in HCC cell lines, but no obvious effects on cell proliferation, apoptosis or cell cycle distribution were detected. CONCLUSIONS: MTHFD2 is overexpressed in HCC, and is associated with poor prognosis and cellular features connected to metastatic disease.

Dramatic antitumor effects of the dual mTORC1 and mTORC2 inhibitor AZD2014 in hepatocellular carcinoma.

The mammalian target of rapamycin (mTOR) has emerged as a critical effector in cell growth, proliferation, survival, angiogenesis, and autophagy through direct interaction with mTORC1 (mTOR complex 1) and mTORC2 (mTOR complex 2). The mTOR axis is aberrantly activated in about 50% of human hepatocellular carcinoma (HCC) cases and thus has become an attractive target for drug development in this disease. Allosteric inhibitors of mTORC1, rapamycin and its derivatives have been used to study in patients with HCC but have not shown significant clinical utility, likely because of the lack of inhibition of mTORC2. In the present study, we describe that AZD2014, a small molecular ATP-competitive inhibitor of mTOR, was a highly potent inhibitor of mTORC1 and mTORC2 in human HCC cells, which led to a more thorough inhibition of mTORC1 than rapamycin, and the inhibition of mTORC2 prevented the feedback activation of AKT signaling. Compared with rapamycin, AZD2014 resulted in more profound proliferation suppression, apoptosis, cell cycle arrest, and autophagy in HCC cells. Notably, we found blockage of both mTORC1 and mTORC2 by AZD2014 to be more efficacious than blockage of mTORC1 alone by rapamycin in inhibiting the migration, invasion and EMT progression of HCC cells. In conclusion, our current results highlight mechanistic differentiation between rapamycin and AZD2014 in targeting cancer cell proliferation, cell cycle, apoptosis, autophagy, migration, invasion and EMT progression, and provide support for further investigation of AZD2014 as an antitumor agent for the treatment of HCC in clinic.

[The preliminary study on the function of methylenetetrahydrofolate dehydrogenase 2 in hepatocellular carcinoma].

OBJECTIVE: To investigate the expression of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) in hepatocellular carcinoma (HCC) tissues and its correlation with clinical parameters. METHOD: Fluorogenic quantitative-polymerase chain reaction (FQ-PCR) was used to measure the MTHFD2 mRNA expression. The MTHFD2 protein expression was detected by immunohistochemical staining in cancerous tissues and adjacent noncancerous counterparts. The relationship of MTHFD2 expression, clinicopathological parameters and the prognosis of hepatocellular carcinoma was subsequently analysed. RESULTS: The MTHFD2 mRNA expression in cancerous tissues was higher than that in adjacent noncancerous counterparts (31/47) (P<0.05). The positive rate of MTHFD2 protein in cancerous tissues was significantly higher than that in adjacent noncancerous counterparts (69.5% vs. 33.9%) (P<0.05). MTHFD2 overexpression was found to correlate with clinical pathological parameters such as tumor metastasis, recurrence and poor prognosis (P<0.05). The patients with overexpressed MTHFD2 had shorter tumor-free survival time. CONCLUSIONS: Overexpression of MTHFD2 in HCC may be a risk factor of tumor metastasis and recurrence. MTHFD2 could be a new biomarker for prognosis of HCC.