Cyclooxygenase-2 overexpression in human basal cell carcinoma cell line increases antiapoptosis, angiogenesis, and tumorigenesis.
Cyclooxygenase-2 (COX-2) is critical for tumor formation, angiogenesis, metastasis, and prognosis. In this study, the role of COX-2 in antiapoptosis, tumorigenesis, and angiogenesis of human basal cell carcinoma (BCC) cells was investigated. Transfection of COX-2 constitutive expression vector into a BCC cell line yielded several overexpressing clones. All transfectants demonstrated remarkable resistance to ultraviolet B-induced apoptosis (confirmed by flow cytometry analysis, morphological change, and DNA fragmentation). Immunoblot analysis revealed marked increases in apoptosis-regulated genes Mcl-1 and Bcl-2. A 10-fold concentrated conditioned medium from COX-2-overexpressing BCC cells exhibited higher angiogenic activity in Matrigel plug and human umbilical vein endothelial cell tube formation assay. Cells exhibited increased levels of vascular endothelial growth factor-A (VEGF-A) mRNA and protein, and secreted VEGF-A and basic fibroblast growth factor (bFGF). COX-2-specific small interfering RNA markedly reduced the secreted species. After 7 weeks of inoculation, the tumor volume of COX-2-overexpressing cells in severe combined immunodeficient mice was significantly greater than that of vector control cells. Immunohistochemical analysis of CD31-positive vessels revealed a two-fold increase in microvessel density in COX-2 tumors, compared to control vector tumors. Our data indicate that Mcl-1 and Bcl-2, as well as VEGF-A and bFGF, are downstream effectors of COX-2-induced antiapoptosis and angiogenesis, respectively.
Tjiu
Jeng-Wei
JW
Department of Dermatology, National Taiwan University Hospital, National Taiwan University College of Medicine, 7 Chung-Shan South Road, Taipei, Taiwan.
Liao
Yi-Hua
YH
Lin
Sung-Jan
SJ
Huang
Yi-Ling
YL
Tsai
Wei-Ling
WL
Chu
Chia-Yu
CY
Kuo
Min-Liang
ML
Jee
Shiou-Hwa
SH
D000818:Animals; D017209:Apoptosis; D002280:Basal Cell Carcinoma / Q000098:blood supply / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D009389:Neovascularization, Pathologic / Q000209:etiology*; D012333:RNA, Messenger / Q000032:analysis
D012333:RNA, Messenger; D051546:Cyclooxygenase 2