Inhibition of AKT2 enhances sensitivity to gemcitabine via regulating PUMA and NF-κB signaling pathway in human pancreatic ductal adenocarcinoma.
Invasion, metastasis and resistance to conventional chemotherapeutic agents are obstacles to successful treatment of pancreatic cancer, and a better understanding of the molecular basis of this malignancy may lead to improved therapeutics. In the present study, we investigated whether AKT2 silencing sensitized pancreatic cancer L3.6pl, BxPC-3, PANC-1 and MIAPaCa-2 cells to gemcitabine via regulating PUMA (p53-upregulated modulator of apoptosis) and nuclear factor (NF)-κB signaling pathway. MTT, TUNEL, EMSA and NF-κB reporter assays were used to detect tumor cell proliferation, apoptosis and NF-κB activity. Western blotting was used to detect different protein levels. Xenograft of established tumors was used to evaluate primary tumor growth and apoptosis after treatment with gemcitabine alone or in combination with AKT2 siRNA. Gemcitabine activated AKT2 and NF-κB in MIAPaCa-2 and L3.6pl cells in vitro or in vivo, and in PANC-1 cells only in vivo. Gemcitabine only activated NF-κB in BxPC-3 cells in vitro. The presence of PUMA was necessary for gemcitabine-induced apoptosis only in BxPC-3 cells in vitro. AKT2 inhibition sensitized gemcitabine-induced apoptosis via PUMA upregulation in MIAPaCa-2 cells in vitro, and via NF-κB activity inhibition in L3.6pl cells in vitro. In PANC-1 and MIAPaCa-2 cells in vivo, AKT2 inhibition sensitized gemcitabine-induced apoptosis and growth inhibition via both PUMA upregulation and NF-κB inhibition. We suggest that AKT2 inhibition abrogates gemcitabine-induced activation of AKT2 and NF-κB, and promotes gemcitabine-induced PUMA upregulation, resulting in chemosensitization of pancreatic tumors to gemcitabine, which is probably an important strategy for the treatment of pancreatic cancer.
Department of General Surgery, The Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, China.
Dong
D
Chen
Department of Pharmacy, The Affiliated Hospital of Medical College, Qingdao University,Qingdao 266003, China.
Min
M
Niu
Department of General Surgery, The Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, China.
Xuelong
X
Jiao
Department of General Surgery, The Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, China.
Kejun
K
Zhang
Department of Oncology, The Affiliated Hospital of Qingdao Medical College, Qingdao University, Qingdao 266003, China.
Jun
J
Liang
Department of General Surgery, The Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, China.
Dianliang
D
Zhang
D000230:Adenocarcinoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000627:therapeutic use / Q000633:toxicity; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D016328:NF-kappa B / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D014183:Transplantation, Heterologous; D015854:Up-Regulation / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; D051017:Apoptosis Regulatory Proteins; C438378:BBC3 protein, human; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D003841:Deoxycytidine; D051057:Proto-Oncogene Proteins c-akt; D000093542:Gemcitabine