Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) exhibit anti-neoplastic (chemoprevention) activity for sporadic cancers and the hereditary cancer predisposition Lynch syndrome (LS/HNPCC). However, the mechanism of NSAID tumor suppression has remained enigmatic. Defects in the core mismatch repair (MMR) genes MSH2 and MLH1 are the principal drivers of LS/HNPCC. Previous work has demonstrated that the villin-Cre(+/-)Msh2(flox/flox) (VpC-Msh2) mouse is a reliable model for LS/HNPCC intestinal tumorigenesis, which is significantly suppressed by treatment with the NSAID aspirin (ASA) similar to human chemoprevention. Here we show that including a TGFβ receptor type-II (Tgfβ-RII) mutation in the VpC-Msh2 mouse (villin-Cre(+/-)Msh2(flox/flox)Tgfβ-RII(flox/flox) ) completely eliminates NSAID tumor suppression. These results provide strong genetic evidence that TGFβ signaling and/or effectors participate in NSAID-dependent anti-neoplastic processes and provide fresh avenues for understanding NSAID chemoprevention and resistance.