OBJECTIVETo evaluate effects of celecoxib (a selective cox-2 inhibitor)combined with fluvastatin (a HMG-CoA reductase inhibitor) on tumor growth and cell apoptosis in hepatocellular carcinoma xenograft in nude mice.

METHODSHepatocellular carcinoma BEL-7402 cells were inoculated subcutaneously into the left armpit of nude mice, the mice (n = 32) were then randomly divided into 4 groups: the control group, the celecoxib group,the fluvastatin group and the combination group. At the end of the study, Tumor Tissues were collected for analysis. Cell apoptosis was determined by flow cytometry analysis and TUNEL assay. Akt, p-Akt and survivin protein levels were measured by Western blot. Statistical comparisons were made using factorial analysis of variance (ANOVA) and multiple comparisons between each two groups were calculated using SNK-q test.

RESULTSThe combination of Celecoxib and fluvastatin resulted in a greater inhibition of tumor growth than either agent alone, the tumor inhibitory rate was 34.0% in the Celecoxib group, 25.0% in the fluvastatin group and 72.2% in the combination group. The percentages of TUNEL--positive cancer cells in the celecoxib and fluvastatin alone treatment groups were 8.5%+/-1.4% and 9.4%+/-1.7% respectively as compared to the control group which was 3.5%+/-0.8%. Combination therapy showed a significantly greater increase in tumor cell apoptosis in comparison with the control and single-therapy groups (apoptotic index: 19.4%+/-3.0%; P value is less than 0.01 versus celecoxib or fluvastatin groups). The results of flow cytometry analysis also showed the same tendency. a small number of apoptotic cells were detected in the control tumours (4.1%+/-1.6%), whereas a large number of apoptotic cells were detected in tumours treated with celecoxib (9.1%+/-2.1%) or fluvastatin (10.1%+/-2.3%) alone; and the combination therapy resulted in even more apoptotic cells (23.6%+/-5.8%; P value is less than 0.01 versus celecoxib or fluvastatin groups). Western blot analysis demonstrated that the combination of celecoxib and fluvastatin significantly down-regulated p-Akt (0.23+/-0.08 versus 1.12+/-0.07 and surviving (0.50+/-0.07 versus 1.47+/-0.19) in BEL-7402 tumours compared with the control (P value is less than 0.01 for all).

CONCLUSIONThe present study provided evidence that treatment with celecoxib in combination with fluvastatin resulted in the inhibition of HCC tumour growth in an in vivo mouse model.