PTOV1 exerts pro-oncogenic role in colorectal cancer by modulating SQSTM1-mediated autophagic degradation of p53.

BACKGROUND

Prostate Tumor Overexpressed 1 (PTOV1) is overexpressed and associated with malignant phenotypes in various types of tumors. However, the detailed roles of PTOV1 and its underlying mechanism in CRC remain unclear.

METHODS

The clinical significance of PTOV1 was assessed in clinical databases and CRC samples. The effects of PTOV1 on the tumor-associated phenotypes of CRC were detected by several in vitro assays and in vivo mouse models. Immunoprecipitation (IP) combined with protein mass spectrometry and Co-Immunoprecipitation (Co-IP) was used to identify p53 interacting with PTOV1. Immunofluorescence assay, western blot and transmission electron microscopy (TEM) analysis were used to evaluated the effects of PTOV1 on autophagy.

RESULTS

Here, we revealed that PTOV1 was highly expressed in human CRC tissues, especially at advanced stages, and associated with reduced survival time among CRC patients. The upregulated PTOV1 promoted cell proliferation, migration, invasion, tumor growth and metastasis of CRC cells in vitro and in vivo. At the molecular level, PTOV1 destabilized p53 by activating autophagy and recruiting p53 for the cargo receptor SQSTM1 directed autophagic degradation. There was a negative expression correlation between PTOV1 and p53 in CRC tissues. Moreover, p53 overexpression or SQSTM1 knockdown reversed the pro-tumor phenotypes of PTOV1 in CRC.

CONCLUSION

Our study unveils the oncogenic role of PTOV1 in CRC progression, which was achieved by promoting SQSTM1 directed autophagic degradation of p53. These findings highlight the potential of targeting the PTOV1-SQSTM1-p53 axis as a therapeutic approach for CRC.