title: Activation of p38 mitogen-activated protein kinase by celecoxib oppositely regulates survivin and gamma-H2AX in human colorectal cancer cells.
abstract: Cancer cells express survivin that facilitates tumorigenesis. Celecoxib has been shown to reduce human colorectal cancers. However, the role and regulation of survivin by celecoxib in colorectal carcinoma cells remain unclear. Treatment with 40-80 muM celecoxib for 24 h induced cytotoxicity and proliferation inhibition via a concentration-dependent manner in RKO colorectal carcinoma cells. Celecoxib blocked the survivin protein expression and increased the phosphorylation of H2AX at serine-193 (gamma-H2AX). The survivin gene knockdown by transfection with a survivin siRNA revealed that the loss of survivin correlated with the expression of gamma-H2AX. Meanwhile, celecoxib increased caspase-3 activation and apoptosis. Celecoxib activated the phosphorylation of p38 mitogen-activated protein (MAP) kinase. The phosphorylated proteins of p38 MAP kinase and gamma-H2AX were observed in the apoptotic cells. SB203580, a specific p38 MAP kinase inhibitor, protected the survivin protein expression and decreased the levels of gamma-H2AX and apoptosis in the celecoxib-exposed cells. The blockade of survivin expression increased the celecoxib-induced cytotoxicity; conversely, overexpression of survivin by transfection with a survivin-expressing vector raised the cancer cell proliferation and resisted the celecoxib-induced cell death. Our results provide for the first time that p38 MAP kinase participates in the down-regulation of survivin and subsequently induces the activation of gamma-H2AX for mediating apoptosis following treatment with celecoxib in human colorectal cancer cells.
authors.affiliation: Institute of Pharmacology and Toxicology, College of Life Sciences, Tzu Chi University, 701, Section 3, Chung-Yang Road, Hualien 970, Taiwan.
authors.forename: Po-Wen
authors.initials: PW
authors.lastname: Hsiao
authors.forename: Chia-Ching
authors.initials: CC
authors.lastname: Chang
authors.forename: Huei-Fang
authors.initials: HF
authors.lastname: Liu
authors.forename: Chuan-Mei
authors.initials: CM
authors.lastname: Tsai
authors.forename: Ted H
authors.initials: TH
authors.lastname: Chiu
authors.forename: Jui-I
authors.initials: JI
authors.lastname: Chao
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D000068579:Celecoxib; D002452:Cell Count; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000378:metabolism*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006657:Histones / Q000096:biosynthesis*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D018613:Microscopy, Confocal; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis* / Q000235:genetics; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D010766:Phosphorylation; D011720:Pyrazoles / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology*; D000077022:Survivin; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: C107489:BIRC5 protein, human; D052246:Cyclooxygenase 2 Inhibitors; C468783:H2AX protein, human; D006657:Histones; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011720:Pyrazoles; D034741:RNA, Small Interfering; D013449:Sulfonamides; D000077022:Survivin; D049452:Green Fluorescent Proteins; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3; D000068579:Celecoxib