Takuto Hara1, Hideaki Miyake2, Nobuyuki Hinata1, Masato Fujisawa1. 1. Division of Urology, Kobe University Graduate School of Medicine, Kobe, Japan. 2. Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan hideakimiyake@hotmail.com.
Abstract
BACKGROUND/AIM: There are several unresolved issues regarding the combined treatment with an immune checkpoint inhibitor and anti-angiogenic agent for renal cell carcinoma (RCC) patients. The purpose of this study was to address the inhibitory effects of programmed death-ligand 1 (PD-L1) expression on growth and sensitivity to sunitinib in the mouse RCC RenCa model. MATERIALS AND METHODS: We established RenCa/sh-PD-L1 by transfecting RenCa cells with a plasmid carrying a short hairpin RNA targeted against PD-L1. The growth pattern of RenCa/sh-PD-L1 with or without sunitinib was compared to that of RenCa cells transfected with control plasmid alone (RenCa/Co). RESULTS: No significant difference in growth or sensitivity to sinitinib was noted between RenCa/sh-PD-L1 and RenCa/Co cells in vitro. The tumor volume in mice subcutaneously injected with RenCa/sh-PD-L1 was significantly smaller than that with RenCa/Co. Treatment of mice bearing each tumor with sunitinib resulted in a significant reduction of the RenCa/sh-PD-L1 tumor compared to the RenCa/Co tumor. Moreover, infiltration by CD8+ T cells of RenCa/sh-PD-L1 tumors was significantly higher than that of RenCa/Co tumors, irrespective of treatment with sunitinib. CONCLUSION: Suppressed expression of PD-L1 could increase tumor-infiltrating CD8+ T cells and result in growth inhibition as well as enhanced sensitivity to sunitinib in the RenCa model. Copyright
BACKGROUND/AIM: There are several unresolved issues regarding the combined treatment with an immune checkpoint inhibitor and anti-angiogenic agent for renal cell carcinoma (RCC) patients. The purpose of this study was to address the inhibitory effects of programmed death-ligand 1 (PD-L1) expression on growth and sensitivity to sunitinib in the mouseRCC RenCa model. MATERIALS AND METHODS: We established RenCa/sh-PD-L1 by transfecting RenCa cells with a plasmid carrying a short hairpin RNA targeted against PD-L1. The growth pattern of RenCa/sh-PD-L1 with or without sunitinib was compared to that of RenCa cells transfected with control plasmid alone (RenCa/Co). RESULTS: No significant difference in growth or sensitivity to sinitinib was noted between RenCa/sh-PD-L1 and RenCa/Co cells in vitro. The tumor volume in mice subcutaneously injected with RenCa/sh-PD-L1 was significantly smaller than that with RenCa/Co. Treatment of mice bearing each tumor with sunitinib resulted in a significant reduction of the RenCa/sh-PD-L1tumor compared to the RenCa/Co tumor. Moreover, infiltration by CD8+ T cells of RenCa/sh-PD-L1 tumors was significantly higher than that of RenCa/Co tumors, irrespective of treatment with sunitinib. CONCLUSION: Suppressed expression of PD-L1 could increase tumor-infiltrating CD8+ T cells and result in growth inhibition as well as enhanced sensitivity to sunitinib in the RenCa model. Copyright