Cyclooxygenase-2 inducing Mcl-1-dependent survival mechanism in human lung adenocarcinoma CL1.0 cells. Involvement of phosphatidylinositol 3-kinase/Akt pathway.
Cyclooxygenase 2 (COX-2) has been reported to be commonly expressed in advanced stages of human lung adenocarcinoma. In this study, the COX-2 constitutive expression vector was transfected into a human lung adenocarcinoma cell line CL1.0 and several clones were obtained which stably expressed COX-2. These COX-2-overexpressed clones demonstrated remarkable resistance to apoptosis induced by Ultraviolet B (UVB) irradiation, vinblastine B (VBL) cell lymphoma-2 (Bcl-2), or other anti-cancer drugs. To understand how COX-2 prevents apoptosis, the investigators examined the expression level of Bcl-2 family members. Mcl-1, but not other Bcl-2 members, was significantly up-regulated by COX-2 transfection or prostaglandin E(2) (PGE(2)) treatment. Treatment of COX-2-overexpressed cells (cox-2/cl.4) with two specific COX-2 inhibitors, NS-398 and celecoxib, caused an effective reduction of the increased level of Mcl-1. These data suggest that the expression level of Mcl-1 is tightly regulated by COX-2. Moreover, transfection of cox-2/cl.4 cells with antisense Mcl-1 enhanced apoptosis induced by UVB irradiation, revealing that Mcl-1 plays a crucial role in cell survival activity mediated by COX-2. Furthermore, COX-2 transfection or PGE(2) treatment evidently activated the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Inhibition of the PI3K pathway by LY294002 or wortmannin effectively attenuated the increased level of Mcl-1 induced by COX-2 or PGE(2). Blocking the PI3K activity with a dominant-negative vector, DN-p85, also greatly diminished the level of Mcl-1 and enhanced UVB-elicited cell death in cells transfected by COX-2. In a similar way, LY294002 inhibited cell survival and Mcl-1 level in PGE(2)-treated CL1.0 cells. These findings suggest that COX-2 promotes cell survival by up-regulating the level of Mcl-1 by activating the PI3K/Akt-dependent pathway.
Lin
M T
MT
Department of Surgery, National Taiwan University Hospital, Taipei 100, Taiwan.
Lee
R C
RC
Yang
P C
PC
Ho
F M
FM
Kuo
M L
ML
D000230:Adenocarcinoma / Q000503:physiopathology*; D000730:Androstadienes / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival; D016895:Culture Media, Serum-Free; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D053938:DNA Fragmentation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D020287:In Situ Nick-End Labeling; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008175:Lung Neoplasms / Q000503:physiopathology*; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D014747:Vinblastine / Q000494:pharmacology; D000077191:Wortmannin
D000730:Androstadienes; D000972:Antineoplastic Agents, Phytogenic; D016895:Culture Media, Serum-Free; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011451:Prostaglandin-Endoperoxide Synthases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2; D014747:Vinblastine; D000077191:Wortmannin; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; C494918:AKT1 protein, human