mTOR inhibition sensitizes human hepatocellular carcinoma cells to resminostat

作者：Peng, Xingang; Zhang, Donghui; Li, Zhengling; Fu, Meili^*; Liu, Haiyan^*

来源：Biochemical and Biophysical Research Communications, 2016, 477(4): 556-562.

DOI：10.1016/j.bbrc.2016.06.060

• Hepatocellular carcinoma
• HDACs
• Resminostat
• mTOR
• Mitochondrial apoptosis pathway
• Chemo-sensitization

Histone deacetylases (HDACs) hyper-activity in hepatocellular carcinoma (HCC) is often associated with patients' poor prognosis. Our previous study has shown that resminostat, a novel HDAC inhibitor (HDACi), activated mitochondrial permeability transition pore (mPTP)-dependent apoptosis pathway in HCC cells. Here we explored the potential resminostat resistance factor by focusing on mammalian target of rapamycin (mTOR). We showed that AZD-2014, a novel mTOR kinase inhibitor, potentiated resminostat-induced cytotoxicity and proliferation inhibition in HCC cells. Molecularly, AZD-2014 enhanced resminostat-induced mPTP apoptosis pathway activation in HCC cells. Inhibition of this apoptosis pathway, by the caspase-9 specific inhibitor Ac-LEHD-CHO, the mPTP blockers (sanglifehrin A/cyclosporine A), or by shRNA-mediated knockdown of mPTP component cyclophilin-D (Cyp-D), significantly attenuated resminostat plus AZD-2014-induced cytotoxicity and apoptosis in HCC cells. Significantly, mTOR shRNA knockdown or kinase-dead mutation (Asp-2338-Ala) also sensitized HCC cells to resminostat, causing profound cytotoxicity and apoptosis induction. Together, these results suggest that mTOR could be a primary resistance factor of resminostat. Targeted inhibition of mTOR may thus significantly sensitize HCC cells to resminostat.

• 出版日期2016-9-2
• 单位青岛大学; 临沂市人民医院