[A study on anticancer activity of tanshinone II A against human breast cancer].

Objective: To investigate the proliferation inhibition and apoptosis-associated genes expression of both human breast cancer cells with estrogen receptor (ER) positive and negative (MCF-7 and MDA-MB-231) which treated with tanshinone II A, and to elucidate its mechanism of activity.
Methods: Human ER positive breast cancer cells (MCF-7) and ER negative cells (MDA-MB-231) were tested in vitro for cytotoxicity of tanshinone II A with MTT method. The effect of tanshinone II A on DNA synthesis and apoptosis of both human breast cancer cells were evaluated with Brdu incorporation and flow cytometry. Immunohistochemistry were applied to test the P53, CerBb-2 and Bcl-2 protein expression of both cells.
Results: After Tanshinone II A treatment, a dose- and time-dependent decreased proliferation in both MCF-7 and MDA-MB-231 cells were observed (P < 0.05) with a IC50 0.25 microg/mL. A decreased BrdU incorporation and an increased apoptosis in both cells were also observed (P < 0.05 and P < 0.01 respectively). Immunohistochemistry test demonstrated that tanshinone A upregulate P53 expression in both cells and also weakly upregulate the CerBb-2 expression in MCF-7 (P < 0.05), whereas no influence on CerBb-2 expression of MDA-MB-231 and on Bcl-2 expression of both cells were demonstrated (P > 0.05).
Conclusion: This study suggested that tanshione II A could inhibit the proliferation, induce apoptosis of ER-positive breast cancer cell MCF-7 and ER-negative breast cancer cell in vitro. The mechanism may be associated with the inhibition of DNA synthesis, induction of apoptosis, but may not with the expression level of gene p53, cer Bb-2 and bcl-2.