Abstract 2386: HDAC6 regulates ERK1’s kinase activity via deacetylation

Abstract

Abstract Extracellular signal-regulated kinases 1/2 (ERK1/2) are important kinases regulating cell proliferation and cell migration, and have been established as therapeutic targets for cancer treatment. Previously, we found that ERK1 phosphorylates histone deacetylase 6 (HDAC6), a class IIb HDAC, to regulate its enzymatic activity. HDAC6 plays an important role in several types of cancers. HDAC6 governs cancer cells’ migration by cooperating with cytoskeleton proteins and their associated proteins, and HDAC6 is arising as a determinant for cisplatin-resistance in non-small cell lung cancer (NSCLC) and ovarian cancer. Here, we have shown that HDAC6 manipulates ERK1’s kinase activity via deacetylation. We demonstrated that both ERK1 and ERK2 interact with HDAC6 physically via GST pull-down assays. To examine whether ERK1/2 are acetylated, we transfected GST-ERK1 or GST-ERK2 into HEK293T cells, and treated the cells with a pan-HDAC inhibitor, Trichostatin A. We showed that the level of acetylated GST-ERK1/2 increased in a dose- and time-dependent manner. Furthermore, when GST-ERK1 or GST-ERK2-expressed cells were treated with an HDAC6-specific inhibitor, ACY-1215, the level of acetylated GST-ERK1/2 increased. These results suggest that HDAC6 is a deacetylase for ERK1/2. In addition, we determined that acetyltransferases CBP and p300 acetylate ERK1/2. We found a novel acetylation site located in ERK1 N-terminus by mass-spectrometry analysis. We then mutated this lysine (K) site with either Glutamic acid (Q) or Arginine (R) to mimic the acetylation or deacetylation status, and performed kinase assays using ELK1 as a substrate. The acetylation mimicking mutant exhibits a decreased kinase activity toward ELK1, while the deacetylation mimicking mutant exhibits a similar level of kinase activity as the wild-type ERK1 does, suggesting that acetylation/deacetylation alters ERK1 enzymatic activities. Therefore, HDAC6 may regulate ERK1’s kinase activity via deacetylation of this site. Furthermore, we have shown that HDAC6 is overexpressed in lung cancer tissue samples and plays an important role in chemo-sensitivity in lung cancer. We predict that inhibition of the HDAC6-ERK1 pathway may provide clinical benefit for lung cancer patients. Citation Format: Jheng-Yu Wu, Xiaohong Zhang. HDAC6 regulates ERK1’s kinase activity via deacetylation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2386. doi:10.1158/1538-7445.AM2017-2386