Inhibition of oogenic JNK prevents primary ovarian insufficiency and infertility induced by DNA-damaging anti-cancer agents

Primary ovarian insufficiency (POI) and related infertility, early menopause, and endocrine disorders are major side effects in young female cancer patients undergoing cancer treatment. Current strategies preserving ovarian functions and fertility can be suboptimal due to concerns of feasibility, efficacy, or safety. Herein, we identify c-Jun N-terminal kinase (JNK) as a pivotal factor regulating the DNA damage response (DDR) signaling in oocytes of primordial follicles in response to DNA-damaging chemotherapy. Using pharmacological inhibition of JNK and a mouse model with oocyte-specific deletion of JNK, together with bioinformatic, molecular, and computational approaches, we show that inhibition of oogenic JNK prevents chemotherapy-induced oocyte apoptosis and POI as well as preserve long-term reproductive cycles and fertility. Mechanistically, JNK is activated upon chemotherapy-induced DNA damage in oocytes of primordial follicles, which further activates the transcription factor TAp63α and triggers oocyte apoptosis. we further used a breast cancer mouse model to demonstrate that JNK inhibition preserves the ovarian reserve without interfering with the anti-cancer efficacy of chemotherapy. Together, our research establishes JNK as a crucial determinant of oocyte apoptosis and POI following DNA-damaging cancer therapy, highlighting JNK as a promising target for developing ovarian protectant and preserving the ovarian reserve, fertility, and ovarian endocrine functions in young female cancer patients.