Abstract 2891: Protein phosphatase 5 regulation of cell motility

Metastasis has been considered as one of the cancer hallmarks. Approximately 90% of cancer-related death is due to cancer metastasis. Tumor cell migration is a prerequisite for cancer metastasis. Protein phosphatase 5 (PP5) is a serine/threonine protein phosphatase that belongs to the phosphoprotein phosphatase (PPP) family including PP1 and PP2A. It is well known that PP5 regulates apoptosis, proliferation, and stress response. However, the role of PP5 in the regulation of cell motility is only beginning to be recognized, and the mechanism of PP5 regulation of cell motility is largely unknown. In this study, our tissue microarray (TMA) studies showed the expression of PP5 increased with the stages of prostate cancer, which is consistent with the previous findings that there is a positive correlation between PP5 overexpression and breast cancer metastases. Furthermore, by the single-cell motility assay, we found that overexpression of PP5 increased the motility of various tumor cells, whereas knockdown of PP5 decreased the cell motility, suggesting that PP5 positively regulates cell motility. As focal adhesion kinase (FAK) is a key regulator of cell motility, and a report has shown that PP5 forms a complex with ASK1, FAK, CXCR4 in wounded alveolar epithelial cancer cells, we examined whether PP5 activates FAK. The Western blotting results showed that overexpression of PP5 did not obviously affect the phosphorylation of FAK. The results suggest that PP5 regulates cell motility through a new mechanism. Further research is on the way to identify how PP5 positively regulates cell motility. (Supported by the Feist-Weiller Cancer Center, LSU Health Sciences Center, Shreveport, LA, USA.) Citation Format: n Li, Shile Huang. Protein phosphatase 5 regulation of cell motility [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2891.