Harmine Hydrochloride from Peganum harmala L. Targets NFAT1 for Proteasomal Degradation to Suppress Ovarian Cancer Progression

Background/Objectives: Ovarian cancer is a prevalent gynecological malignancy with high mortality rates worldwide. Harmine hydrochloride (HMH), a tricyclic β-carboline alkaloid derived from the seeds of the medicinal plant Peganum harmala L., has demonstrated anti-tumor activity. This study investigated the effect of HMH on ovarian cancer and elucidated its underlying molecular mechanism. Methods: The anti-ovarian cancer effects of HMH were evaluated using the CCK-8 assay, cell cycle and apoptosis analyses, as well as a cell migration assay. The RNA-seq was utilized to explore the mechanisms of HMH. Western blot, qRT-PCR and IF were employed for further validation of the expression levels of relevant molecules. The Kaplan–Meier (KM) curve was conducted to evaluate the possible link between NFAT1 levels and the prognosis of ovarian cancer. The biological functions of NFAT1 were explored through siRNA knockdown experiments. Auto-dock molecular docking and DARTS were used to analyze the direct interaction between HMH and NFAT1. The in vivo efficacy of HMH was examined through bioluminescence imaging of intraperitoneal xenografts established with luciferase-expressing HEY cells. Results: HMH induced apoptosis, arrested the cell cycle, and suppressed migration of HEY and CAOV3 cells. NFAT1 was highly expressed in the nucleus of HEY and CAOV3 cells and promoted ovarian cancer progression. In addition, low NFAT1 expression levels had significantly improved overall survival and progression-free survival. Moreover, HMH reduced NFAT1 expression and reversed Ion-induced NFAT1 levels in ovarian cancer cell nuclei. The molecular docking and DARTS results suggested that HMH binds to NFAT1. Treatment with MG132 effectively blocked HMH-induced NFAT1 downregulation. Furthermore, HMH effectively blocked intraperitoneal xenograft development, and extended the life span of animals bearing HEY/Luc cells, when used alone or in combination with CDDP. Conclusions: The research indicated that HMH exerts anti-ovarian cancer effects, at least in part, by targeting NFAT1. Additionally, our research revealed that NFAT1 promotes ovarian cancer progression, and plays a significant role in HMH’s anti-cancer activity. These results may aid in the development of novel candidates for ovarian cancer and identify a new target for ovarian cancer treatment.