Abstract 569: Acetylcholine-induced YAP stabilization enhances HIF-1 signaling under hypoxia via the nAchR-α7/PI3K/PDPK1 pathway in pancreatic cancer cells.

Abstract The pancreas is highly innervated by the autonomic nervous system. Recent studies have extensively addressed the potential role of the autonomic nervous system in the development of pancreatic ductal adenocarcinoma (PDAC).Hypoxia-inducible factor-1α (HIF-1α) regulates tumor adaptation to hypoxia by controlling genes linked to angiogenesis, metastasis, and therapy resistance. We previously showed that neurotransmitter acetylcholine (Ach) enhances HIF-1α expression in pancreatic cancer cells via the nAchR-α7/PDPK1/YAP pathway under hypoxia, but the underlying molecular mechanisms remained unclear. Following our previous findings, this study aims to elucidate the molecular signaling mechanism by which Ach regulates HIF-1α expression under hypoxic conditions in pancreatic cancer cells. Here, we treated human pancreatic cancer cells with Ach under 0.5% oxygen. Protein levels, phosphorylation, and interactions were assessed using Western blot, qRT-PCR, and co-immunoprecipitation. PI3K, PDPK1, and YAP expression were silenced by siRNA. In vivo, the effect of Ach was tested using tail-vein Ach injections in a subcutaneous xenograft mouse model. We found that Ach activated PI3K downstream of nAchR-α7, increasing PDPK1 phosphorylation. This reduced YAP phosphorylation at serine 397, stabilizing YAP and promoting its nuclear translocation. In the nucleus, YAP bound to HIF-1α, enhancing its stability and transcriptional activity. Knockdown of PI3K, PDPK1, or YAP suppressed Ach-induced HIF-1α upregulation. In vivo, Ach significantly promoted tumor growth in mice implanted with control pancreatic cancer cells, but had no effect in mice bearing tumors derived from nAchR-α7-silenced cells. Analysis of clinical datasets revealed that high nAchR-α7 expression correlates with poor prognosis in PDAC patients. Collectively, these findings reveal that Ach promotes pancreatic tumor progression under hypoxia via the nAchR-α7/PI3K/PDPK1/YAP pathway, which stabilizes HIF-1α. This signaling axis represents a promising therapeutic target in acetylcholine-associated pancreatic cancer. Citation Format: Yunmi Cho, Ha Hyeong Kim, Eun-Taex Oh. Acetylcholine-induced YAP stabilization enhances HIF-1 signaling under hypoxia via the nAchR-α7/PI3K/PDPK1 pathway in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 569.