PDCD1 and hepatocellular carcinoma: The cytotoxicity profiles of the compounds were also tested in Jurkat cells, CHO cells and human hepatic carcinoma cell line HepG2; and finally, the ability of the compounds to block PD-1/PD-L1 interaction and to improve interleukin-2 (IL-2) cytokine release was validated using a commercially available PD-1/PD-L1 cell-based assay and peripheral blood derived mononuclear cells (PBMCs) from healthy donors.