Effects Of Celecoxib On Proliferation,apoptosis And Nucleostemin Expression In Human Breast Cancer Cell Line SKBR3

The incidence of breast cancer in the world, especially in China, is increasing in recent years. HER-2/neu oncogene can be detected in about 20%～30% of the breast cancer patients. Research showed that overexpression of COX-2 gene in mammary endothelial cells was able to induce breast cancer.As the relationship between breast cancer and COX-2 has caused a wide public concern, the effect of cyclooxygenase-2 inhibitors and associated treatments on the cancer progress has drawn a great attention in current research.Nucleostemin (NS) is a P53-binding protein which is expressed in stem cells and cancer cells. The basic function of NS is involved in modulating the proliferation of stem cells and cancer cells. However, the mechanism of NS gene in maintaining proliferation of these cells remains unclear. Celecoxib, a selective cyclooxygenase-2 inhibitor, was used in this research to observe its effect on cultured human breast cancer cell line Skbr3 that highly expressed HER-2/neu. The methods associated with cell proliferation and apoptosis were applied, such as, observation on apoptotic morphological change, MTT assay, the test for the activity of caspase3, evaluation on apoptotic rate, cell cycle by Flow cytometry (FCM). Expression of NS protein and associated protein were detected by immune fluorescent staining and Western-blot. Results show that the growth of Skbr3 cells was inhibited by celecoxib in a concentration dependent manner. Celecoxib could upregulate the expression of NS protein and P53 protein and simultaneously downregulate the expression of COX-2 protein and CyclinD1 protein. Morphological observation indicates that celecoxib-treated cells show several typical apoptotic features.Meanwhile the typical apoptosis peak is detected by FCM. The change of apoptotic rate and cell cycle were concentration dependent manner and the cell percentage in G0/G1 phase increased. We concluded that the effect of celecoxib on Skbr3 cells might be related with modulating NS expression.