Effects of Taoerqi extract on proliferation and apoptosis of human breast carcinoma cell line MCFª²7

    LI Guoª²Yuan£¬ MA Lan£¬ GE Riª²Li

    Research Center of High Altitude Medicine, Qinghai Medical College, Xining 810001, China

    ¡¾Abstract¡¿ AIM: To investigate the effects and related mechanism of Taoerqi on the proliferation inhibition and onset of apoptosis in breast carcinoma cell line MCFª²7. METHODS: Antiproliferative effect of Taoerqi extract against MCFª²7 was tested by MTT assay, morphologic changes of MCFª²7 were observed by inverted microscope, electron microscope and HE staining, and cell apoptosis percentage and cell cycle phase distribution of MCFª²7 were measured by flow cytometric assay. The expressions of proliferationª² and apoptosisª²associated proteins were determined by immunocytochemical method. RESULTS: A timeª²dependent and doseª²dependent proliferation inhibition was demonstrated in Taoerqi extract. With the Taoerqi extract treatment of 1, 2 and 3 mg/L for 72 h, the inhibitory rate was 43.0%, 54.9%, 78.5% respectively. The characteristic morphological changes of apoptosis were observed in cells after treated by 2 mg/L of Taoerqi, and many multinucleate giant cells were also found. Taoerqi induced a G2/M cell cycle arrest and the apoptosis was timeª² and doseª²dependent. With the treatment of 2 mg/L Taoerqi for 48 h, the protein expressions of PCNA and Bclª²2 decreased from (154.78¡À0.16) and (85.56¡À0.09) to (78.46¡À0.15) and (40.43¡À0.07) (P<0.01), while p21WAF1/CIP1 and cª²Myc increased from (92.32¡À0.12) and (114.48¡À0.14) to (125.54¡À0.09) and (156.52¡À0.08) (P<0.01). CONCLUSION: The timeª²dependent and doseª²dependent proliferation inhibitory effect of Taoerqi extract on breast cancer cells appears to be caused by the upª²regulation of p21WAF1/CIP1 expression, downª²regulation of PCNA expression, and the apoptosis is related to the downª²regulation of antiª²apoptotic protein Bclª²2 and the upª²regulation of cª²Myc protein. G2/M arrest is also associated with apoptosis. ......