Cystine deprivation triggers CD36-mediated ferroptosis and dysfunction of tumor infiltrating CD8+ T cells.

Cancer cells develop multiple strategies to evade T cell-mediated killing. On one hand, cancer cells may preferentially rely on certain amino acids for rapid growth and metastasis. On the other hand, sufficient nutrient availability and uptake are necessary for mounting an effective T cell anti-tumor response in the tumor microenvironment (TME). Here we demonstrate that tumor cells outcompete T cells for cystine uptake due to high Slc7a11 expression. This competition induces T-cell exhaustion and ferroptosis, characterized by diminished memory formation and cytokine secretion, increased PD-1 and TIM-3 expression, as well as intracellular oxidative stress and lipid-peroxide accumulation. Importantly, either Slc7a11 deletion in tumor cells or intratumoral cystine supplementation improves T cell anti-tumor immunity. Mechanistically, cystine deprivation in T cells disrupts glutathione synthesis, but promotes CD36 mediated lipid uptake due to dysregulated cystine/glutamate exchange. Moreover, enforced expression of glutamate-cysteine ligase catalytic subunit (Gclc) promotes glutathione synthesis and prevents CD36 upregulation, thus boosting T cell anti-tumor immunity. Our findings reveal cystine as an intracellular metabolic checkpoint that orchestrates T-cell survival and differentiation, and highlight Gclc as a potential therapeutic target for enhancing T cell anti-tumor function.

The Application of Complementary and Alternative Medicine in Polycystic Ovary Syndrome Infertility.

Polycystic ovary syndrome (PCOS) is a lifelong reproductive endocrine disease, which is the most common cause of anovular infertility. Modern medicine mainly treats infertile patients with PCOS by improving living habits, ovulation induction therapy, and assisted reproductive technology (ART), but the effect is not satisfied. Complementary alternative medicine (CAM) has conspicuous advantages in the treatment of PCOS infertility due to its good clinical efficacy, wide mechanism of action, and no obvious adverse reactions, but its safety and effectiveness in the treatment of PCOS infertility have not been proved. Based on the existing clinical and experimental studies, this paper looks for the therapeutic effect and the mechanism behind it, and explores the safety and effectiveness of its treatment in PCOS infertility, in order to provide reference for future clinical treatment and experimental research.