Cholestasis-induced neutrophil phenotypic transformation contributes to the immune escape of colorectal liver metastasis

Cholestasis, a serious complication of liver metastasis (LM), contributes to dismal prognosis in patients with colorectal cancer and LM. However, the mechanism underlying the effect of cholestasis on the development of LM or pre-metastatic microenvironment in the liver remains elusive. In this study, we discovered that cholestasis accelerated the progression of LM and is associated with increased neutrophil infiltration, T-cell exclusion, and exhaustion. Besides, Tβ-MCA and GCA promoted the expression of Arg1 and iNOS in neutrophils via the p38/MAPK signaling pathway. The significant suppression of the activation and cytotoxic effects of CD8+ T cells during co-culture with BA-pretreated neutrophils indicated that BAs directly induce the polarization of immunosuppressive neutrophils. Importantly, targeting BA anabolism with Obeticholic acid effectively suppressed the LM of colorectal cancer in a cholestasis mouse model. Our findings suggest that cholestasis, associated with the failure to achieve drainage of primary BAs, accelerates the progression of LM by remodeling the tumor immune microenvironment. Moreover, targeting BA anabolism with OCA may represent a therapeutic strategy for cholestasis-associated LM of colorectal cancer.