ADAM17 regulates hepatic DNA damage repair and tumour formation

BackgroundHepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths worldwide. Still, therapy options for this tumour entity are limited and novel therapeutic options are highly sought after. Genomic instability of hepatocytes promotes oncogenic transformation and underlies the regulation of micro-environmental signalling cues. The membrane-bound a disintegrin and metalloprotease (ADAM) 17 is a major regulator of micro-environmental signals through the proteolytic release of paracrine factors. However, its role in hepatic DNA damage repair and its contribution to hepatic tumourigenesis is still unclear. MethodsWe investigated the effect of ADAM17 on diethylnitrosamine (DEN)-induced acute DNA damage and subsequent DNA damage repair by utilizing mice with ubiquitous or myeloid-specific genetic deficiency in ADAM17. DNA double strand breaks and inflammation were investigated by immunofluorescence of liver tissue sections. tumourigenesis in mice with myeloid-specific ADAM17-deficiency was investigated in a chemically induced hepatocarcinogenesis model. ResultsADAM17 on myeloid cells, in particular Kupffer cells is essentially involved in the non-cell autonomous regulation of DNA damage repair in hepatocytes. Parenchymal ADAM17 regulates hepatocyte fate and recruitment of infiltrating myeloid cells. Furthermore, myeloid ADAM17 promotes hepatic tumour initiation and correlates with poor prognosis in human HCC. ConclusionsWe identified ADAM17, in particular on myeloid cells as an essential driver of hepatic tumourigenesis and as a potential novel drug target for the treatment of hepatic malignancies.