Uricase sensitizes hepatocellular carcinoma cells to 5-fluorouracil through uricase-uric acid-UMP synthase axis

Conventional chemotherapy plays a key role in hepatocellular carcinoma (HCC) treatment, however, with intrinsic or acquired chemoresistance being a major constraint. Here, we aimed to identify potential target to reverse such chemoresistance. In the present study, we found significant difference in uridine monophosphate synthetase (UMPS) expression between 5-FU resistant and sensitive HCC cell lines and the overexpression or downregulation of UMPS impacted 5-FU response in HCC cells. We further found that inhibition of UMPS activity with uric acid at concentration present in human plasma decreased the 5-FU sensitivity of HCC cells, while reduction of uric acid levels with uricase improved the 5-FU sensitivity of HCC cells as well as colorectal cancer cells. In vivo studies also suggested that modulation of uric acid levels did affect 5-FU sensitivity of tumors. These data indicated that UMPS was correlated with the 5-FU resistance in HCC cells and uricase sensitized cancer cells to 5-FU through uricase-uric acid-UMP synthase axis, which provided a potential strategy to improve the efficacy of 5-FU-based chemotherapy for human cancers.