Neutrophil-derived serine proteases induce FOXA2-mediated autophagy dysfunction and exacerbate colitis-associated carcinogenesis via protease activated receptor 2.

Autophagy plays a critical role in colitis-associated colorectal cancer (CAC). However, non-autonomous regulation of macroautophagic/autophagic flux during inflammation remains largely unexplored. Here, we show that F2rl1/Par2 deficiency (F2rl1[ΔIEC]) aggravated azoxymethane-dextran sulfate sodium-induced CAC based on tumor number and burden, promoted autophagy dysfunction characterized by SQSTM1/p62 accumulation and autophagosome-lysosome fusion inhibition in IECs, and reduced lysosomal acidification by suppressing FOXA2-induced V-ATPase ATP6V0E1 transcription. FOXA2 or ATP6V0E1 overexpression rescued autophagy impairment, reactive oxygen species accumulation, and DNA damage induced by F2RL1 deficiency in vitro and in vivo. Neutrophil-derived serine proteases suppressed FOXA2 expression, causing autophagy dysfunction. F2RL1 knockout completely blocked the effects of neutrophil proteases on FOXA2 and ATP6V0E1. The correlation between neutrophil and FOXA2-ATP6V0E1 activities was validated in ulcerative colitis and colorectal carcinoma. Therefore, F2RL1 deficiency in intestinal epithelial cells suppressed FOXA2 expression, leading to V-ATPase-mediated autophagic dysfunction and exacerbating CAC. Neutrophils may contribute to impaired autophagy and promote CAC by inactivating canonical F2RL1/PAR2 signaling via its derived proteases. F2RL1/PAR2 signaling may participate in maintaining intestinal homeostasis via autophagy. These findings provide useful insights into F2RL1/PAR2 and its cleaving serine proteases in CAC and would help in developing new therapeutic strategies for this malignancy.Abbreviations: AOM: azoxymethane; ATP6V0C: ATPase H+ transporting V0 subunit c; ATP6V0E1: ATPase H+ transporting V0 subunit e1; ATP6V1C2: ATPase H+ transporting V1 subunit C2; ATP6V1F: ATPase H+ transporting V1 subunit F; CAC: colitis-associated colorectal cancer; CRC: colorectal cancer; CTSB: cathepsin B; CTSG: cathepsin G; DEGs: differentially expressed genes; DSS: dextran sulfate sodium; FOXA2: forkhead box protein A2; F2RL1: F2R like trypsin receptor 1; IBD: inflammatory bowel disease; IECs: intestinal epithelial cells; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; ROS: reactive oxygen species; SQSTM1/p62: sequestosome 1; TFs: transcription factors; UC: ulcerative colitis.