Caulerpin alleviates cyclophosphamide-induced ovarian toxicity by modulating macrophage-associated granulosa cell senescence during breast cancer chemotherapy.

For fertility preservation, preventing chemotherapy-induced premature ovarian insufficiency (POI) in patients with breast cancer is challenging. Our previous study suggested that caulerpin, a marine indole alkaloid, exerts antitumor effects on breast cancer cells. However, the potential effects of caulerpin on ovarian tissues remain unknown. In the present study, xenograft tumors derived from the MDA-MB-231 breast cancer cell line were established in a female BALB/c nude mouse model. Cyclophosphamide (CTX) alone caused remarkable ovarian damage, including irregular estrous cycles, follicle loss, and reduced expression of anti-Mullerian hormone (AMH) and follicle-stimulating hormone receptor (FSHR), whereas ovarian toxicity was largely reduced after caulerpin treatment in mice and in vitro. The gene signature of the ovaries of CTX-treated tumor-bearing mice revealed differentially expressed genes (DEGs) that regulate two important processes, namely, macrophage polarization and cellular senescence, as well as the activation of the p53/NF-κB signaling pathway. In vitro, CTX induced M1 macrophage polarization in THP-1 cells, which was accompanied by activation of the p53/NF-κB signaling pathway. Additionally, senescence was upregulated in the ovaries of CTX-treated tumor-bearing mice and in granulosa cells (GCs) cocultured with THP-1 cells exposed to LPS/IFN-γ, characterized by increased activity of senescence-associated β-galactosidase (SAβG), increased ROS levels and elevated levels of senescence-related markers (p53, p21 and p38MAPK). Furthermore, caulerpin or a p53 inhibitor (pifithrin-α) modulated CTX-induced M1 polarization in macrophages, thereby delaying GC senescence. These findings demonstrated that caulerpin contributes to alleviating CTX-induced ovarian toxicity by modulating M1 macrophage polarization through the p53/NF-κB signaling pathway, which promotes the senescence of GCs by inducing ROS production.Thus, caulerpin may be a potential therapeutic strategy for breast cancer patients.