Histone deacetylase 5 promotes the proliferation and invasion of lung cancer cells.

Histone deacetylase 5 (HDAC5), as a member of the class IIa family of HDACs, is frequently dysregulated in human malignancies. However, little is known regarding the specific role of HDAC5 in lung cancer. We aimed to evaluate HDAC5 expression in human lung cancer and to determine the effects of HDAC5 on lung cancer cells. First, the expression levels of both HDAC5 protein and mRNA were evaluated in lung cancer tissues and cell lines by western blot analysis and RT‑qPCR, and the results suggested that HDAC5 was significantly upregulated in human lung cancer tissues and cell lines. To address the effects of HDAC5 on the biological behavior of human lung adenocarcinoma cells, we generated human lung cancer A549 cell lines in which HDAC5 was either overexpressed or depleted. The results indicated that overexpression of HDAC5 significantly promoted the proliferation and invasion, and inhibited the apoptosis of A549 cells. On the contrary, HDAC5 knockdown largely decreased the proliferation and invasion and enhanced the apoptosis of A549 cells. Furthermore, we demonstrated that HDAC5 overexpression promoted the expression of DLL4, Six1, Notch 1 and Twist 1 in A549 cells. Downregulation of HDAC5 caused a significant inhibition of the expression of DLL4, Six1, Notch 1 and Twist 1 in A549 cells. Taken together, our data demonstrated that HDAC5 displayed a significant upregulation in lung cancer, and elevated HDAC5 might be involved in the potentiation of proliferation and invasion of lung cancer cells, as well as the inhibition of lung cancer cell apoptosis by the upregulation of DLL4, Six1, Notch 1 and Twist 1. The present study may provide an evidence for the potential application of HDAC5 inhibitors in the therapy of lung cancer.