大荨麻提取物对乳腺癌细胞恶性生物学行为的影响及其可能的机制

目的：探讨大荨麻提取物对乳腺癌细胞增殖、凋亡和细胞周期的影响，并初步探讨其可能的作用机制。方法：用不同质量浓度的大荨麻提取物（0、1、2、4、8、16、32、64 mg/ml）处理乳腺癌细胞MCF-7和MDA-MB-231 24 h，MTT法检测细胞增殖活力，选择中位抑制浓度附近的浓度（5和10 mg/ml）作为给药浓度分别处理MCF-7和MDA-MB-231细胞24 h后，平板克隆形成实验和流式细胞术分别检测大荨麻提取物对乳腺癌细胞增殖、周期和凋亡的影响，WB法检测对细胞周期和凋亡相关蛋白以及PI3K/AKT信号通路相关蛋白表达的影响。在MCF-7细胞用5 mg/ml大荨麻提取物处理的同时转染过表达AKT质粒（大荨麻+AKT组），转染空载质粒为对照组（大荨麻+vec组），WB法检测过表达效率，比较过表达AKT对细胞增殖、周期和凋亡的影响。结果：各大荨麻提取物处理组 MCF-7 和 MDA-MB-231细胞增殖活力均显著低于对照组（P<0.05或P<0.01）；与对照组比较，5或10 mg/ml大荨麻处理组乳腺癌细胞的克隆形成数显著减少，G0/G1期细胞占比和凋亡率显著增加（P<0.05或P<0.01），P21、BAX蛋白表达显著升高而Cyclin D1、CDK4、Bcl2蛋白以及p-PI3K、p-AKT蛋白表达显著降低（P<0.05或P<0.01）。大荨麻+AKT 组 p-AKT 和 AKT 蛋白表达显著高于大荨麻+vec 组，克隆数、S 期和 G2/M 期细胞占比均高于大荨麻+vec 组（P<0.05 或 P<0.01），G0/G1期细胞占比和凋亡率低于大荨麻+vec组（P<0.05或P<0.01）。结论：大荨麻提取物可以抑制乳腺癌细胞增殖、促进凋亡且阻滞细胞在G0/G1期，其作用机制可能与抑制PI3K/AKT信号通路相关。

Effects of Urtica dioica extract on malignant biological behaviors of breast cancer cells and its possible mechanism

Objective: To investigate the effect of Urtica dioica extract on the proliferation, apoptosis, and cell cycle of breast cancer cells, and to primarily explore the possible mechanism. Methods: Breast cancer MCF-7 and MDA-MB-231 cells were treated with different concentrations of Urtica dioica extract (0,1,2,4,8,16,32,64 mg/ml) for 24 h, and the cell viability was detected by MTT. The concentrations around the median inhibitory concentration, which were 5 and 10 mg/ml, were selected to treat MCF-7 and MDA-MB-231 cells for 24 h, respectively. Plate clone formation assay was applied to detect cell proliferation, Flow cytometry was used to detect cell cycle and apoptosis, and WB was used to determine the expression of cell cycle and apoptosis-related proteins as well as PI3K/AKT signaling pathway-related proteins. AKT was simultaneously overexpressed in MCF-7 cells that were treated with 5 mg/ml Urtica dioica extract (Urtica+AKT group), and the cells transfected with empty vectors was used as control group (Urtica+vec group). The overexpression efficiency was detected by WB, and the effects of AKT overexpression on cell proliferation, cell cycle, and apoptosis were explored. Results: The viability of MCF-7 and MDA-MB-231 cells in each Urtica treated group was significantly lower than that in the control group (P<0.05, P<0.01). Compared with the control group, the number of clone formation of breast cancer cells was significantly reduced, while the proportion of cells in the G0/G1 phase and the apoptosis rate were significantly increased in the 5 or 10 mg/ml Urtica treatment groups (P<0.05, P<0.01); in addition, the protein expression of P21 and Bax was significantly increased,while the protein expression of Cyclin D1, CDK4, Bcl2, p-PI3K and p-AKT was significantly decreased (P<0.05, P<0.01) in Urtica treatment groups. The protein expression of p-AKT and AKT in the Urtica+AKT group was significantly higher than that in the Urtica+vec group, and the number of clone formation and proportion of cells in the S phase and G2/M phase were higher than that in the Urtica+vec group, and the proportion of cells in the G0/G1 phase and the apoptosis rate were lower than that in the Urtica+vec group (P<0.05, P<0.01). Conclusion: The Urtica dioica extract can inhibit the proliferation and promote the apoptosis of breast cancer cells,and block the cells at G0/G1 phase, the mechanism of which may be related to the inhibition of PI3K/AKT signaling pathway.