Repurposing ketotifen as a therapeutic strategy for neuroendocrine prostate cancer by targeting the IL-6/STAT3 pathway

Purpose Neuroendocrine prostate cancer (NEPC), a highly aggressive subtype of prostate cancer displaying resistance to hormone therapy, presents a poor prognosis and limited therapeutic options. Here, we aimed to find novel medication therapies for NEPC and explore the underlying mechanism. Methods A high-throughput drug screening utilizing an FDA-approved drug library was performed and ketotifen, an antihistamine agent, was identified as a potential therapeutic candidate for NEPC. The whole-transcriptome sequencing analysis was conducted to explore mechanism of ketotifen inhibitory in NEPC. Multiple cell biology and biochemistry experiments were performed to confirm the inhibitory effect of ketotifen in vitro. A spontaneous NEPC mice model ( PBCre4:Pten f/f ; Trp53 f/f ;Rb1 f/f ) was used to reveal the inhibitory effect of ketotifen in vivo. Results Our in vitro experiments demonstrated that ketotifen effectively suppressed neuroendocrine differentiation, reduced cell viability, and reversed the lineage switch via targeting the IL-6/STAT3 pathway. Our in vivo results showed that ketotifen significantly prolonged overall survival and reduced the risk of distant metastases in NEPC mice model. Conclusion Our findings repurpose ketotifen for antitumor applications and endorse its clinical development for NEPC therapy, offering a novel and promising therapeutic strategy for this formidable cancer subtype.