erastin and Ovarian-Neoplasms

Erastin is a small molecule identified in chemical screen that is capable of inducing ferropotosis. There is collective evidence proving that erastin-induced ferroptosis exhibits anti-tumor potential within diverse caners, such as ovarian cancer (OC). However, most OC cells show relative resistance to ferroptosis induced by erastin. M2-polarized tumor-associated macrophages (TAMs) have an important effect on the OC tumor microenvironment (TME), which makes M2 polarization a noticeable part in the context of OC therapy. The immunomodulatory effects of erastin on ferroptosis-resistant OC cells remain poorly understood. Here, we found that low concentration of erastin greatly promoted ferroptosis-resistant OC cell invasion and migration via STAT3-mediated M2 polarization of macrophages. As revealed by in-vitro experimental results, erastin significantly increased metastases of ferroptosis-resistant OC, and the percentage of M2 macrophage infiltration was also raised after erastin treatment. Furthermore, erastin augmented IL-8 production of macrophages, and pharmacological blockage of IL-8 partially abrogated the stimulatory effect of erastin on ferroptosis-resistant OC cells. This study demonstrates a new mechanism undering the tumor-promoting activity of erastin and has implications for the STAT3/IL-8 axis as a potential target for ferroptosis-resistant OC cells to improve overall anti-tumor efficacy.

Topics: Female; Ferroptosis; Humans; Interleukin-8; Ovarian Neoplasms; Piperazines; STAT3 Transcription Factor; Tumor Microenvironment

Cisplatin-based chemotherapy is the first-line treatment for ovarian cancer. However, acquired resistance to cisplatin treatment or serious side effects often occurs in ovarian cancer, and thus, there is an urgent need for effective and combined therapies to overcome such obstacles. In the present study, we aimed to uncover synergistic effects between erastin and cisplatin (CDDP) in inhibiting ovarian cancer cell growth by inducing ferroptosis in vitro and in vivo.. We performed a CCK-8 assay to detect cell viability in response to erastin alone or in combination with cisplatin and provided further confirmation by western blotting analysis. Transmission electron microscopy and flow cytometry analysis were used to depict the characteristics of ferroptosis. In addition, an ovarian cancer tumor xenograft was built to verify the effects in vivo.. CDDP induced multiple modes of cell death-including ferroptosis in ovarian cancer cell lines. Mechanistically, erastin triggered ferroptosis and increased the levels of reactive oxygen species (ROS) so as to augment the cytotoxic effect of cisplatin. Combination therapy based on CDDP and erastin appeared to maximize the therapeutic effects while minimizing side effects in ovarian cancer both in vitro and in vivo.. Collectively, our results indicate that erastin works synergistically with cisplatin to inhibit ovarian cancer cell growth, which may be manipulated by a ROS-mediated mechanism that enhances cisplatin therapy, and offers a novel strategy for overcoming cisplatin therapy resistance.

Topics: Cell Line, Tumor; Cisplatin; Female; Ferroptosis; Humans; Ovarian Neoplasms; Piperazines

Ferroptosis is an iron-dependent, lipid peroxide-mediated cell death that may be exploited to selective elimination of damaged and malignant cells. Recent studies have identified that small-molecule erastin specifically inhibits transmembrane cystine-glutamate antiporter system x. We treated ovarian cancer cells with erastin and examined cell viability, cellular ROS and metabolites of the transsulfuration pathway. We also depleted cystathionine β-synthase (CBS) and NRF2 to investigate the CBS and NRF2 dependency in erastin-resistant cells.. We found that prolonged erastin treatment induced ferroptosis resistance. Upon exposure to erastin, cells gradually adapted to cystine deprivation via sustained activation of the reverse transsulfuration pathway, allowing the cells to bypass erastin insult. CBS, the biosynthetic enzyme for cysteine, was constantly upregulated and was critical for the resistance. Knockdown of CBS by RNAi in erastin-resistant cells caused ferroptotic cell death, while CBS overexpression conferred ferroptosis resistance. We determined that the antioxidant transcriptional factor, NRF2 was constitutively activated in erastin-resistant cells and NRF2 transcriptionally upregulated CBS. Genetically repression of NRF2 enhanced ferroptosis susceptibility.. Based on these results, we concluded that constitutive activation of NRF2/CBS signalling confers erastin-induced ferroptosis resistance. This study demonstrates a new mechanism underlying ferroptosis resistance, and has implications for the therapeutic response to erastin-induced ferroptosis.

Topics: Apoptosis; Cystathionine beta-Synthase; Drug Resistance, Neoplasm; Female; Ferroptosis; Humans; Iron; Lipid Peroxidation; NF-E2-Related Factor 2; Ovarian Neoplasms; Piperazines; Reactive Oxygen Species; Signal Transduction