Novel Withanolides from Tubocapsicum anomalum Suppress Triple-Negative Breast Cancer by Triggering Apoptosis and p53-ASCT2-SLC7A11-Mediated Ferroptosis.

Triple-negative breast cancer (TNBC) is a malignant breast cancer. There is an urgent need for effective drugs to be developed for TNBC. Tubocapsicum anomalum (T. anomalum) has been reported to have an anti-tumor effect, and six novel withanolides were isolated from it and designated as TAMEWs. However, its anti-TNBC effect is still unknown. The results of an MTT assay indicated a higher sensitivity of TNBC cells to TAMEWs compared to other cells. TAMEWs induced apoptosis via mitochondrial dysfunction. They caused increased levels of lipid ROS and Fe2+, with downregulation of GSH and cystine uptake, and it has been confirmed that TAMEWs induced ferroptosis. Additionally, the results of Western blotting indicate that TAMEWs significantly decrease the expressions of ferroptosis-related proteins. Through further investigation, it was found that the knockdown of the p53 gene resulted in a significant reversal of ferroptosis and the expressions of its associated proteins SLC7A11, ASCT2, and GPX4. In vivo, TAMEWs suppressed TNBC growth with no obvious damage. The IHC results also showed that TAMEWs induced apoptosis and ferroptosis in vivo. Our findings provide the first evidence that TAMEWs suppress TNBC growth through apoptosis and ferroptosis.

Synergistic antitumor effects of Peiminine and Doxorubicin on breast cancer through enhancing DNA damage via ZEB1.

Peiminine, the primary biologically active compound from Fritillaria thunbergii Miq., has demonstrated significant pharmacological activities. Doxorubicin is one of the most potent chemotherapeutic agents for breast cancer (BC). This study was designed to investigate the efficacy and underlying mechanisms of Peiminine combined with Doxorubicin in treating BC. Our results demonstrated that the combination of Peiminine and 1 mg/kg Doxorubicin exhibited more significant suppression of tumor growth compared with the monotherapy in MDA-MB-231 xenograft nude mice model, which is comparable to the effect of 3 mg/kg Doxorubicin in vivo. Notably, the 3 mg/kg Doxorubicin monotherapy resulted in organ toxicity, specifically in the liver and heart, whereas no toxicity was observed in the combination group. In vitro, this combined treatment exhibited a synergistic reduction on the viability of BC cells. Peiminine enhanced the cell cycle arrest and DNA damage induced by Doxorubicin. Furthermore, the combination treatment effectively blocked DNA repair by inhibiting the MAPKs signaling pathways. And ZEB1 knockdown attenuated the combined effect of Peiminine and Doxorubicin on cell viability and DNA damage. In conclusion, our study found that the combination of Peiminine and Doxorubicin showed synergistic inhibitory effects on BC both in vivo and in vitro through enhancing Doxorubicin-induced DNA damage. These findings support that their combination is a novel and promising therapeutic strategy for treating BC.