Clinical candidate and genistein analogue AXP107‐11 has chemoenhancing functions in pancreatic adenocarcinoma through G protein‐coupled estrogen receptor signaling

Despite advances in cancer therapeutics, pancreatic cancer remains difficult to treat and often develops resistance to chemotherapies. We have evaluated a bioavailable genistein analogue, AXP107‐11 which has completed phase Ib clinical trial, as an approach to sensitize tumor cells to chemotherapy. Using organotypic cultures of 14 patient‐derived xenografts (PDX) of pancreatic ductal adenocarcinoma, we found that addition of AXP107‐11 indeed sensitized 57% of cases to gemcitabine treatment. Results were validated using PDX models in vivo. Further, RNA‐Seq from responsive and unresponsive tumors proposed a 41‐gene treatment‐predictive signature. Functional and molecular assays were performed in cell lines and demonstrated that the effect was synergistic. Transcriptome analysis indicated activation of G‐protein‐coupled estrogen receptor (GPER1) as the main underlying mechanism of action, which was corroborated using GPER1‐selective agonists and antagonists. GPER1 expression in pancreatic tumors was indicative of survival, and our study proposes that activation of GPER1 may constitute a new avenue for pancreatic cancer therapeutics.