Ectopic expression of FBXO31 dramatically inhibited xenograft tumor growth in nude mice. miR-20a and miR-17 mimics inhibited, whereas the inhibitor of miR-20a and miR-17 increased, the expression of FBXO31, respectively. miR-20a and miR-17 directly bind to the 3'-UTR of FBXO31.
One of these factors is an F-box protein, FBXO31, a candidate tumour suppressor encoded in 16q24.3, a region in which there is loss of heterozygosity in breast, ovarian, hepatocellular and prostate cancers.
Our recent report indicates that FBXO31 functions as a tumor suppressor in gastric cancer, and the loss of FBXO31 protein is associated with a higher malignant phenotype and poorer prognosis.
The SCF<sup>FBXO46</sup> ubiquitin ligase complex mediates degradation of the tumor suppressor FBXO31 and thereby prevents premature cellular senescence.
This study was designed to investigate the expression profile of FBXO31 in HCC and the possibility that FBXO31 might function as a tumor suppressor in HCC cell lines.
We propose that FBXO31 functions as a tumor suppressor by generating SCF(FBXO31) complexes that target particular substrates, critical for the normal execution of the cell cycle, for ubiquitination and subsequent degradation.