NF90 Regulates PARP1 MRNA Stability in Hepatocellular Carcinoma

Poly (ADP-ribose) polymerase 1 (PARP1) is an ADP- ribosylation enzyme and plays important roles in a variety of cellular processes, including DNA damage response and tumor development. However, the post-transcriptional regulation of PARP1 remains largely unknown. In this study, we identified that the mRNA of PARP1 is associated with nuclear factor 90 (NF90) by RNA immunoprecipitation plus sequencing (RIP-seq) assay. The mRNA and protein levels of PARP1 are dramatically decreased in NF90-depleted cells, and NF90 stabilizes PARP1's mRNA through its 3'UTR. Moreover, the expression levels of PARP1 and NF90 are positively correlated in hepatocellular carcinoma (HCC). Finally, we demonstrated that NF90-depleted cells are sensitive to PARP inhibitor Olaparib (AZD2281) and DNA damage agents. Taken together, these results suggest that NF90 regulates PARP1 mRNA stability in hepatocellular carcinoma cells, and NF90 is a potential target to inhibit PARP1 activity.