Effects And Mechanism Of Scorpion Venom Heat-resistant Protein On Apoptosis Of Breast Cancer Cells Cultured In Vitro

ObjectiveIncidence of breast cancer in our country increased year by year, which became the most common malignant tumor in women. Seeking high efficient and low toxicity anticancer drugs and treatment methods are hot spots of medicine research. Scorpion venom (SV) is a biological toxin, which isolated from the venom of Buthus martensi Karsch. Scorpion venom heat-resistent protein (SVHRP) used in experiment was purified from SV, its toxicity decreased, drug effects increased. Previous research showed SVHRP inhibited the growth of some tumor cells. The aim of the research is to observe the effects of SVHRP on apoptosis of breast cancer cell (MCF-7) ciltured in vitro and to discuss its mechanism.MethodsBreast cancer MCF-7 cells treated with different concentration of SVHRP for 6,12,24 and 48 hours, MTT assay was used to detect absorbance (OD) value and calculate inhibition ratio; the apoptotic ratio and the cell cycle was analyzed by flow cytometry, the expression of Bcl-2 and Bax were assessed by immunocytochemistry method.Results1. MTT resultsSVHRP inhibited the growth of MCF-7 cells in a dose-and time-dependent manner. The inhibition ratio was the maximum (56.4%) when 0.1μg/ml SVHRP treated MCF-7 cells for 24 hours.2. Flow cytometry results Apoptotic peak appeared in DNA bargraph of flow cytometry. Quantitative analysis showed the apoptotic ratio of MCF-7 cells on 0.1, 0.01μg/ml SVHRP group was 14.18%,11.39% respectively, both difference were significance compared with control group (6.18%) (P<0.05). Compared with control group, the number of cells in SVHRP group descended gradually in G1 stage, increased gradually in S stage.3. Immunocytochemistry resultsMCF-7 cells treated by 0.1,0.01μg/ml SVHRP for 24 hours, positive expression rate of Bcl-2 was 10.64%,35.16%, which were lower than control group; positive expression rate of Bax was 39.07%,35.15%, which were higher than control group.ConclusionsSVHRP has effects of growth inhibiting and inducing apoptosis on human breast cancer cell line MCF-7, which probably correlated with down-regulation of Bcl-2 gene expression and up-regulation of Bax gene expression.