DNA-PKcs is important for Akt activation and gemcitabine resistance in PANC-1 pancreatic cancer cells |
| |
Authors: | Hao Hu Yuanlong Gu Yi QianBenshun Hu Congyuan ZhuGaohe Wang Jianping Li |
| |
Affiliation: | The Hepatobiliary Center, The Third Hospital Affiliated to Nantong University, Wuxi City, Jiangsu Province 214000, China |
| |
Abstract: | Pancreatic cancer is one of the most aggressive human malignancies with extremely poor prognosis. The moderate activity of the current standard gemcitabine and gemcitabine-based regimens was due to pre-existing or acquired chemo-resistance of pancreatic cancer cells. In this study, we explored the potential role of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in gemcitabine resistance, and studied the underlying mechanisms. We found that NU-7026 and NU-7441, two DNA-PKcs inhibitors, enhanced gemcitabine-induced cytotoxicity and apoptosis in PANC-1 pancreatic cancer cells. Meanwhile, PANC-1 cells with siRNA-knockdown of DNA-PKcs were more sensitive to gemcitabine than control PANC-1 cells. Through the co-immunoprecipitation (Co-IP) assay, we found that DNA-PKcs formed a complex with SIN1, the latter is an indispensable component of mammalian target of rapamycin (mTOR) complex 2 (mTORC2). DNA-PKcs–SIN1 complexation was required for Akt activation in PANC-1 cells, while inhibition of this complex by siRNA knockdown of DNA-PKcs/SIN1, or by DNA-PKcs inhibitors, prevented Akt phosphorylation in PANC-1 cells. Further, SIN1 siRNA-knockdown also facilitated gemcitabine-induced apoptosis in PANC-1 cells. Finally, DNA-PKcs and p-Akt expression was significantly higher in human pancreatic cancer tissues than surrounding normal tissues. Together, these results show that DNA-PKcs is important for Akt activation and gemcitabine resistance in PANC-1 pancreatic cancer cells. |
| |
Keywords: | MTT, 3-(4,5-dimethyl-thiazol-2-yl)2,5-diphenyl tetrazolium bromide DNA-PK, DNA-dependent protein kinase DNA-PKcs, DNA-PK catalytic subunit mTOR, mammalian target of rapamycin mTORC2, mTOR complex 2 PI, propidium iodide PI3K, phosphatidylinositol-3-kinase SIN1, SAPK-interacting protein 1 |
本文献已被 ScienceDirect 等数据库收录! |
|