PTEN activation through K163 acetylation by inhibiting HDAC6 contributes to tumour inhibition

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN), an important tumour-suppressor gene, is mutated, downregulated or dysfunctional in many tumours. The phosphatase activity of PTEN depends on membrane translocation (activation). As promising anti-cancer agents, histone deacetylase (HDAC) inhibitors, particularly trichostatin A (TSA), can promote PTEN membrane translocation, but the underlying mechanism remains unknown. In this study, we revealed that non-selective HDAC inhibitors, namely, TSA or suberoylanilide hydroxamic acid (SAHA), induced PTEN membrane translocation through PTEN acetylation at K163 by inhibiting HDAC6. K163 acetylation inhibited the interaction of the PTEN C-tail with the remaining part of PTEN, resulting in PTEN membrane translocation. Overexpression of wild-type PTEN, but not K163-mutated PTEN, facilitated the inhibition of cell proliferation, migration and invasion, as well as xenograft tumour growth, induced by SAHA or tubastatin A, an HDAC6-specific inhibitor. These results indicated that PTEN activation by inhibiting HDAC6 significantly contributed to tumour inhibition. Therefore, non-selective HDAC or HDAC6-specific inhibitors may be more clinically suitable to treat tumours without PTEN mutations or deletions.