Immunotherapy against the Cystine/Glutamate Antiporter xCT Improves the Efficacy of APR-246 in Preclinical Breast Cancer Models

Cystine/cysteine metabolism regulates the progression and response to treatment of triple‑negative breast cancer (Review)

Breast cancer is the most prevalent neoplasm affecting women globally, of which a notable proportion of cases are triple-negative breast cancer (TNBC). However, there are limited curative treatment options for patients with TNBC, despite advancements in the field. Amino acids and amino acid transporters serve vital roles in the regulation of tumor metabolism. Notably, cystine and cysteine can interconvert via a redox reaction, with cysteine exerting control on cell survival and growth and exogenous cystine serving a crucial role in the proliferation of numerous types of cancers. Breast cancer has been reported to disrupt the cystine/cysteine metabolism pathway, as cystine and cysteine transporters affect the development and growth of tumors. The present review aims to provide a comprehensive overview of the metabolic pathways involving cystine and cysteine in normal and TNBC cells. Furthermore, the roles of cystine and cysteine transporters in TNBC progression and metastasis and their potential as therapeutic targets for treatment of TNBC are evaluated.

FOXQ1 inhibits breast cancer ferroptosis and progression via the circ_0000643/miR-153/SLC7A11 axis

Dysregulation of ferroptosis is involved in breast cancer progression and therapeutic responses. Inducing ferroptosis can be a potential therapeutic strategy for breast cancer treatment. Forkhead box Q1 (FOXQ1) is an oncogenic transcription factor that highly expressed and related with poor outcomes in various tumors. However, the specific effects of FOXQ1 on ferroptosis in breast cancer is unclear. In this study, we intended to explore the functions and potential mechanisms of FOXQ1 in breast cancer ferroptosis. By CCK-8, colony formation, wound healing, transwell and ferroptosis related assays, we explored the functions of FOXQ1 in breast cancer ferroptosis and progression. Through bioinformatics analysis of public database, luciferase reporter assay, RIP and ChIP assay, we investigated the potential mechanisms of FOXQ1 in breast cancer ferroptosis and progression. We found that FOXQ1 was overexpressed in breast cancer and associated with worse survival. Additionally, inhibition of FOXQ1 suppressed breast cancer ferroptosis and progression. Mechanically, we confirmed that FOXQ1 could bind to the promoter of circ_0000643 host gene to increase the levels of circ_0000643, which could sponge miR-153 and enhance the expression of SLC7A11, leading to reduced cell ferroptosis in breast cancer cells. Targeting the FOXQ1/circ_0000643/miR-153/SLC7A11 axis could be a promising strategy in breast cancer treatment.

A comprehensive overview of recent developments on the mechanisms and pathways of ferroptosis in cancer: the potential implications for therapeutic strategies in ovarian cancer

Cancer cells adapt to environmental changes and alter their metabolic pathways to promote survival and proliferation. Metabolic reprogramming not only allows tumor cells to maintain a reduction-oxidation balance by rewiring resources for survival, but also causes nutrient addiction or metabolic vulnerability. Ferroptosis is a form of regulated cell death characterized by the iron-dependent accumulation of lipid peroxides. Excess iron in ovarian cancer amplifies free oxidative radicals and drives the Fenton reaction, thereby inducing ferroptosis. However, ovarian cancer is characterized by ferroptosis resistance. Therefore, the induction of ferroptosis is an exciting new targeted therapy for ovarian cancer. In this review, potential metabolic pathways targeting ferroptosis were summarized to promote anticancer effects, and current knowledge and future perspectives on ferroptosis for ovarian cancer therapy were discussed. Two therapeutic strategies were highlighted in this review: directly inducing the ferroptosis pathway and targeting metabolic vulnerabilities that affect ferroptosis. The overexpression of SLC7A11, a cystine/glutamate antiporter SLC7A11 (also known as xCT), is involved in the suppression of ferroptosis. xCT inhibition by ferroptosis inducers (e.g., erastin) can promote cell death when carbon as an energy source of glucose, glutamine, or fatty acids is abundant. On the contrary, xCT regulation has been reported to be highly dependent on the metabolic vulnerability. Drugs that target intrinsic metabolic vulnerabilities (e.g., GLUT1 inhibitors, PDK4 inhibitors, or glutaminase inhibitors) predispose cancer cells to death, which is triggered by decreased nicotinamide adenine dinucleotide phosphate generation or increased reactive oxygen species accumulation. Therefore, therapeutic approaches that either directly inhibit the xCT pathway or target metabolic vulnerabilities may be effective in overcoming ferroptosis resistance. Real-time monitoring of changes in metabolic pathways may aid in selecting personalized treatment modalities. Despite the rapid development of ferroptosis-inducing agents, therapeutic strategies targeting metabolic vulnerability remain in their infancy. Thus, further studies must be conducted to comprehensively understand the precise mechanism linking metabolic rewiring with ferroptosis.

Special Issue: Cancer Metastasis and Therapeutic Resistance

Metastasis and resistance to cancer therapeutics are critical barriers to curing cancer. This special issue entitled "Cancer Metastasis and Therapeutic Resistance" contains nine original contributions. The articles span a variety of human cancers, including breast, lung, brain, prostate, and skin and touch upon significant areas of interest such as cancer stem cell function, cancer immunology, and glycosylation.