Ubiquitin-specific peptidase 5 and ovarian tumor deubiquitinase 6A are differentially expressed in p53+/+ and p53-/- HCT116 cells

Most proteins undergo ubiquitination, a process by which ubiquitin proteins bind to their substrate proteins; by contrast, deubiquitination is a process that reverses ubiquitination. Deubiquitinating enzymes (DUBs) function to remove ubiquitin proteins from the protein targets and serve an essential role in regulating DNA repair, protein degradation, apoptosis and immune responses. Abnormal regulation of DUBs may affect a number of cellular processes and may lead to a variety of human diseases, including cancer. Therefore, it is important to identify abnormally expressed DUBs to identify DUB-related diseases and biological mechanisms. The present study aimed to develop a multiplex polymerase chain reaction screening platform comprising primers for various DUB genes. This assay was used to identify p53-related DUBs in HCT116 p53(+/+) and p53(-/-) cells. The results demonstrated that ubiquitin-specific peptidase 5 (USP5) and ovarian tumor deubiquitinase 6A (OTUD6A) were differentially expressed in p53(+/+) and p53(-/-) HCT116 cells. Based on the data obtained through DUB screening, the protein expression levels of USP5 and OTUD6A were examined by western blotting, which confirmed that both of these DUBs were also expressed differentially in p53(+/+) and p53(-/-) HCT116 cells. In conclusion, results from the DUB screening performed by the present study revealed that the expression of USP5 and OTUD6A may be affected by p53, and this method may be useful for the rapid and cost-effective identification of possible biomarkers.