Zhang Yu, Yuan Bo, Bian Baolin, Zhao Haiyu, Kiyomi Anna, Hayashi Hideki, Iwatani Yui, Sugiura Munetoshi, Takagi Norio
Department of Applied Biochemistry, Tokyo University of Pharmacy & Life Sciences, Hachioji, Japan.
Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China.
Front Oncol. 2021 Aug 26;11:711220. doi: 10.3389/fonc.2021.711220. eCollection 2021.
Development of new therapeutic strategies for breast cancer is urgently needed due to the sustained emergence of drug resistance, tumor recurrence and metastasis. To gain a novel insight into therapeutic approaches to fight against breast cancer, the cytocidal effects of hellebrigenin (Helle) and arenobufagin (Areno) were investigated in human estrogen receptor (ER)-positive breast cancer cell line MCF-7 and triple-negative breast cancer cell line MDA-MB-231. Helle exhibited more potent cytotoxicity than Areno in both cancer cells, and MCF-7 cells were more susceptible to both drugs in comparison with MDA-MB-231 cells. Apoptotic-like morphological characteristics, along with the downregulation of the expression level of Bcl-2 and Bcl-xL and the upregulation of the expression level of Bad, were observed in Helle-treated MCF-7 cells. Helle also caused the activation of caspase-8, caspase-9, along with the cleavage of poly(ADP-ribose) polymerase in MCF-7 cells. Helle-mediated necrosis-like phenotype, as evidenced by the increased propidium iodide (PI)-positive cells was further observed. G/M cell cycle arrest was also induced by Helle in the cells. Upregulation of the expression level of p21 and downregulation of the expression level of cyclin D1, cyclin E1, cdc25C and survivin were observed in MCF-7 cells treated with Helle and occurred in parallel with G/M arrest. Autophagy was triggered in MCF-7 cells and the addition of wortmannin or 3-MA, two well-known autophagy inhibitors, slightly but significantly rescued the cells. Furthermore, similar alterations of some key molecules associated with the aforementioned biological phenomena were observed in MDA-MB-231 cells. Intriguingly, the numbers of PI-positive cells in Helle-treated MCF-7 cells were significantly reduced by wortmannin and 3-MA, respectively. In addition, Helle-triggered G/M arrest was significantly corrected by wortmannin, suggesting autophagy induction contributed to Helle-induced cytotoxicity of breast cancer cells by modulating necrosis and cell cycle arrest. Collectively, our results suggested potential usefulness of both Helle and Areno in developing therapeutic strategies to treat patients with different types of breast cancer, especially ER-positive breast cancer.
由于耐药性、肿瘤复发和转移的持续出现，乳腺癌新治疗策略的开发迫在眉睫。为了深入了解对抗乳腺癌的治疗方法，研究了嚏根草苷（Helle）和华蟾毒精（Areno）对人雌激素受体（ER）阳性乳腺癌细胞系MCF-7和三阴性乳腺癌细胞系MDA-MB-231的杀伤作用。在两种癌细胞中，Helle比Areno表现出更强的细胞毒性，并且与MDA-MB-231细胞相比，MCF-7细胞对两种药物更敏感。在Helle处理的MCF-7细胞中观察到凋亡样形态特征，同时Bcl-2和Bcl-xL表达水平下调，Bad表达水平上调。Helle还导致MCF-7细胞中caspase-8、caspase-9的激活以及聚（ADP-核糖）聚合酶的裂解。进一步观察到Helle介导的坏死样表型，碘化丙啶（PI）阳性细胞增加证明了这一点。Helle还诱导细胞发生G/M期阻滞。在用Helle处理的MCF-7细胞中观察到p21表达水平上调，细胞周期蛋白D1、细胞周期蛋白E1、cdc25C和存活素表达水平下调，并且与G/M期阻滞同时发生。MCF-7细胞中触发了自噬，添加渥曼青霉素或3-MA这两种著名的自噬抑制剂后，细胞略有但显著地得到挽救。此外，在MDA-MB-231细胞中观察到与上述生物学现象相关的一些关键分子的类似变化。有趣的是，渥曼青霉素和3-MA分别显著减少了Helle处理的MCF-7细胞中PI阳性细胞的数量。此外，渥曼青霉素显著纠正了Helle触发的G/M期阻滞，表明自噬诱导通过调节坏死和细胞周期阻滞促进了Helle诱导的乳腺癌细胞毒性。总的来说，我们的结果表明Helle和Areno在开发治疗不同类型乳腺癌患者，特别是ER阳性乳腺癌的治疗策略中具有潜在用途。
