School of Pharmaceutical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, PR China.
School of Life Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, PR China.
Chem Biol Interact. 2023 Jun 1;378:110487. doi: 10.1016/j.cbi.2023.110487. Epub 2023 Apr 16.
Scutebarbatine A (SBT-A), a diterpenoid alkaloid, has exerted cytotoxicity on hepatocellular carcinoma cells in our previous works. Here, the antitumor activity of SBT-A in breast cancer cells and the underlying mechanism were explored. The anti-proliferative effect of SBT-A was measured by trypan blue staining, 5-ethynyl-2'-deoxyuridine (EdU) incorporation and colony formation assay. DNA double-strand breaks (DSBs) were evaluated by observing the nuclear focus formation of γ-H2AX. Cell cycle distribution was assessed by flow cytometry. Apoptosis was determined by a TUNEL assay. Intracellular reactive oxygen species (ROS) generation and superoxide production were measured with 2', 7'-dichlorofluorescein diacetate (DCFH-DA) and dihydroethidium (DHE) staining, respectively. The results indicated that SBT-A showed a dose-dependent cytotoxic effect against breast cancer cells while revealing less toxicity toward MCF-10A breast epithelial cells. Moreover, SBT-A remarkably induced DNA damage, cell cycle arrest and apoptosis in both MDA-MB-231 and MCF-7 cells. SBT-A treatment increased the levels of ROS and cytosolic superoxide production. Pretreatment with N-acetyl cysteine (NAC), a ROS scavenger, was sufficient to block viability reduction, DNA damage, apoptosis and endoplasmic reticulum (ER) stress caused by SBT-A. By exposure to SBT-A, the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK) was upregulated, while the phosphorylation of extracellular signal-regulated kinase (ERK) was downregulated. In addition, SBT-A inhibited the EGFR signaling pathway by decreasing EGFR expression and phosphorylation of Akt and p70S6K. As mentioned above, SBT-A has a potent inhibitory effect on breast cancer cells through induction of DNA damage, apoptosis and ER stress via ROS generation and modulation of MAPK and EGFR/Akt signaling pathway.
刺桐巴豆堿 A（SBT-A）是一种二萜生物碱，在我们之前的工作中已显示出对肝癌细胞的细胞毒性。在此，研究了 SBT-A 在乳腺癌细胞中的抗肿瘤活性及其潜在机制。通过台盼蓝染色、5-乙炔基-2'-脱氧尿苷（EdU）掺入和集落形成实验来测量 SBT-A 的抗增殖作用。通过观察 γ-H2AX 的核焦点形成来评估 DNA 双链断裂（DSB）。通过流式细胞术评估细胞周期分布。通过 TUNEL 测定法确定细胞凋亡。通过 2'，7'-二氯荧光素二乙酸酯（DCFH-DA）和二氢乙啶（DHE）染色分别测量细胞内活性氧（ROS）的产生和超氧化物的产生。结果表明，SBT-A 对乳腺癌细胞具有剂量依赖性的细胞毒性作用，而对 MCF-10A 乳腺上皮细胞的毒性较小。此外，SBT-A 可显著诱导 MDA-MB-231 和 MCF-7 细胞中的 DNA 损伤、细胞周期停滞和细胞凋亡。SBT-A 处理增加了 ROS 水平和细胞质中超氧化物的产生。ROS 清除剂 N-乙酰半胱氨酸（NAC）预处理足以阻断 SBT-A 引起的细胞活力降低、DNA 损伤、凋亡和内质网（ER）应激。通过暴露于 SBT-A，c-Jun N-末端激酶（JNK）和 p38 丝裂原激活蛋白激酶（p38MAPK）的磷酸化上调，而细胞外信号调节激酶（ERK）的磷酸化下调。此外，SBT-A 通过降低 EGFR 表达以及 Akt 和 p70S6K 的磷酸化来抑制 EGFR 信号通路。如前所述，SBT-A 通过诱导 DNA 损伤、细胞凋亡和 ER 应激，通过 ROS 生成以及调节 MAPK 和 EGFR/Akt 信号通路，对乳腺癌细胞具有很强的抑制作用。
