Effect of indomethacin on Bfl-1, WISP-1 and proliferating cell nuclear antigen in colon cancer cell line HCT116 cells

BACKGROUND:  Non-steroidal anti-inflammatory drugs such as indomethacin can inhibit the growth of tumors through both the cyclooxygenase-2 (COX-2) dependant and COX-2 independent pathways, but the exact mechanism has not yet been shown. In our previous study, COX-2 independent proteins (Bfl-1, WISP-1 and proliferating cell nuclear antigens [PCNA]) in indomethacin-treated colorectal cancer cells with the use of proteomics technology had been identified. OBJECTIVES:  To study and confirm the effect of indomethacin on the expression of Bfl-1, WISP-1 and PCNA in human colon cancer line HCT116 cells and the COX-2 independent tumor inhibiting pathway. METHODS:  Human colon cancer cell line HCT116 cells were divided into a treatment with indomethacin (IC 50) group, and a treatment with dimethyl sulfoxide (DMSO) as a control group for 48 h. The expression of Bfl-1, WISP-1 and PCNA, mRNA and protein were determined by a real-time quantitative PCR and Western blot, respectively. RESULTS:  Indomethacin down-regulated the expression of Bfl-1, WISP-1 and PCNA mRNA in vitro (9.53 ± 0.15 vs 27.87 ± 0.12, 7.37 ± 0.58 vs 20.17 ± 0.58, 5.17 ± 0.06 vs 0.87 ±  0.06). Indomethacin also down-regulated the expression of Bfl-1, WISP-1 and PCNA protein (40.01 ± 1.61 vs 43.76 ± 1.63, 22.50 ± 1.17 vs 30.30 ± 1.55, 17.69 ± 1.18 vs 20.80 ± 1.08). CONCLUSIONS:  Inducing apoptosis and inhibiting proliferation contribute to the anticancer activity of indomethacin via COX-2 independent pathway of Bfl-1, WISP-1 and PCNA. This further confirms the results of our previous study.