Histone deacetylase 10 knockout activates chaperone-mediated autophagy and accelerates the decomposition of its substrate

Histone deacetylase (HDAC) 10 is a member of class IIb HDACs, but its deacetylation targets and functions are poorly characterized. Recent investigation has proposed that HDAC10 deacetylates heat shock cognate protein 70 kDa (HSC70) after interaction. HSC70 plays an important role in chaperone-mediated autophagy (CMA), binding CMA substrates and transporting them to lysosomes. However, it has not been clarified whether HDAC10 is involved in CMA. In this study, we established the HDAC10 knockout HeLa cell line and evaluated its CMA activity to determine whether HDAC10 participates in regulating CMA. In HDAC10 knockout cells, lysosome-associated protein type 2A (LAMP2A) protein level increased and LAMP2A-positive lysosomes accumulated around the nucleus. Moreover, GAPDH, which is a well-known CMA substrate, was delivered to LAMP2A-positive lysosomes and degraded in HDAC10 knockout cells more efficiently than in wild type HeLa cells. These results suggest that CMA is activated in HDAC10 knockout cells. Meanwhile, turnover assay using LC3 and p62, which are macroautophagy markers, indicated that autophagic flux was fully functioning in HDAC10 knockout cells as well as in wild type HeLa cells. In conclusion, HDAC10 participated in regulating CMA, and HDAC10 knockout activated CMA and accelerated degradation of a CMA substrate.

Expression and Function of Histone Deacetylase 10 (HDAC10) in B Cell Malignancies

Histone deacetylase 10 (HDAC10) belongs to the class IIb HDAC family and its biological role remains mostly unidentified. A decreased HDAC10 expression has been reported in patients with aggressive solid tumors (Osada et al. Int J Cancer 112: 26-32, 2004; Jin et al. Int J Clin Exp Pathol 7: 5872-5879, 2014), suggesting that loss of HDAC10 expression might confer a survival advantage to malignant cells. Consequently, results from our lab suggests that overexpression of HDAC10 in aggressive mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) Z138c and MEC1 cells, respectively, resulted in a rapid induction of cell death in vitro with only 5 % of cells being alive at 48 h, cell cycle arrest, and up-regulation of co-stimulatory molecules. Here we present several standard methods to study the function of HDAC10 in B cell malignancies.

Decreased expression of histone deacetylase 10 predicts poor prognosis of gastric cancer patients

Aberrant expression of histone deacetylase (HDACs) was associated with carcinogenesis and progression of various tumors. However, the association of HDAC10 with clinical outcomes in gastric cancer patients is unclear. Thus, the objective of the current study was to evaluate the association of expression level of HDAC10 with clinicopathologic factors and prognosis of patients with gastric cancer. The expression level of HDAC10 in 179 paraffin-embedded gastric cancer tissue specimens was examined by immunohistochemistry (IHC). As a result, we found that expression of HDAC10 in gastric cancer was significantly decreased in gastric cancer tissues as compared with adjacent tissues (51.4% vs. 87.3%, P < 0.001). HDAC10 expression was significantly correlated with gender (P = 0.023), tumor size (P = 0.015), histological grade (P = 0.009), tumor invasion (P = 0.033), lymph node metastatic status (P = 0.019) and tumor stage (P = 0.004), but not correlated with age and lauren classification (all P > 0.05). Kaplan-Meier survival curves showed that the overall survival rate was significantly lower in the patients with low expression of HDAC10 compared with those patients with high HDAC10 (P < 0.001). Moreover, multivariate analysis revealed that HDAC10 expression was an independent prognostic factor for gastric cancer patients (P = 0.001). These results suggest that HDAC10 expression could see as a prognosis marker for gastric cancer patients.