Histone Deacetylase as a Valuable Predictive Biomarker and Therapeutic Target in Immunotherapy for Non-Small Cell Lung Cancer / Journal of the Korean Cancer Association, 대한암학회지

ABSTRACT

Purpose@#Histone deacetylase inhibitors (HDACis) are epigenetic regulators and used clinically for hematopoietic malignancies. Recently, HDACis have received attention as a factor that modulates the immune system. In this study, the role of histone deacetylase (HDAC) expression as a predictive marker in lung cancer patients who were treated with immune checkpoint inhibitors (ICIs) and the role of HDACi and ICI combination treatment in the mouse tumor model were analyzed. @*Materials and Methods@#The overall response rate (ORR) and progression-free survival (PFS) were analyzed by the expression of HDAC. In vitro assay, the mRNA and protein expression levels of cytokines and programmed death-ligand 1 (PD-L1) were analyzed after HDACi treatment. In vivo assay, TC-1 tumor-bearing mice were treated with HDACi and mouse programmed cell death 1 (PD-1) inhibitor. @*Results@#The HDAC6 low expression group showed high ORR and prolonged PFS. When the selective HDAC6 inhibitor was administered to the A549 cell line, the levels of interleukin-1β and interleukin-6 decreased and the expression of PD-L1 was reduced. Mice that received both the mouse PD-1 inhibitor and pan-HDACi had a smaller tumor size than that of the mice from the control group. Moreover, mice treated with the mouse PD-1 inhibitor and pan-HDACi generated greater numbers of E7-specific CD8+ T cells. @*Conclusion@#HDAC6 expression can predict the prognosis of non–small cell lung cancerpatients who were treated with ICIs. Furthermore, co-treatment with HDACi and PD-1 inhibitor was shown to decrease the tumor growth rate and create a favorable tumor microenvironment for cytotoxic T lymphocytes in the TC-1 mouse model.