Specific COX-2 inhibitor, meloxicam, suppresses proliferation and induces apoptosis in human HepG2 hepatocellular carcinoma cells.
OBJECTIVE
Cyclooxygenase-2 (COX-2) is associated with carcinogenesis. The aim of this study was to investigate the expression of COX-2 in four hepatocellular carcinoma (HCC) cell lines, and evaluate the effect of a selective COX-2 inhibitor, meloxicam, in HepG2, a high COX-2 expressing cell line.


METHODS
Expression of COX-2 was detected using RT-PCR, Western blotting and immunohistochemical analysis. Cell proliferation was measured using MTT assay. Cell cycle distribution was determined by flow cytometry. Apoptosis was detected with TUNEL method. Expression of proliferating cell nuclear antigen (PCNA), cell cycle regulatory proteins including cyclins A, B1, D1 and E, and apoptosis-related proteins including Fas, Fas ligand and Bcl-2 were examined using Western blotting.


RESULTS
Cyclooxygenase-2 was intensely expressed in HepG2, HLE and BEL7402 cells, but weakly expressed in SMMC-7402 cells. Meloxicam suppressed proliferation of HepG2 cells in a dose- and time-dependent manner, resulting in cell cycle arrest in S phase and cell accumulation in G0/G1 phase. Expression of PCNA, cyclin A but not cyclin B1, cyclin D1 or cyclin E was down-regulated by meloxicam. Meloxicam also induced apoptosis of HepG2 cells, with increased expression of Fas ligand, but the expression of Fas and Bcl-2 was not affected by meloxicam treatment.


CONCLUSIONS
The present study demonstrates that the specific COX-2 inhibitor meloxicam suppresses proliferation and induces apoptosis in HCC cells that express COX-2, suggesting that COX-2 inhibition may offer a novel chemopreventive and therapeutic approach for HCC.
Li
Jie
J
Hepatosurgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Chen
Xiaoping
X
Dong
Xuesong
X
Xu
Zongzhen
Z
Jiang
Hongchi
H
Sun
Xueying
X
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D051546:Cyclooxygenase 2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D053222:Fas Ligand Protein / Q000187:drug effects / Q000235:genetics; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007527:Isoenzymes / Q000037:antagonists & inhibitors; D008113:Liver Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D000077239:Meloxicam; D051379:Mice; D018809:Proliferating Cell Nuclear Antigen / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013843:Thiazines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*
D016861:Cyclooxygenase Inhibitors; D053222:Fas Ligand Protein; D007527:Isoenzymes; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D013843:Thiazines; D013844:Thiazoles; D051546:Cyclooxygenase 2; D000077239:Meloxicam