Inhibitory Effect of Interference with PD-L1 Expression on B-cell lymphoma in Mice

Abstract

To investigate the potential inhibitory effect of interference with PD-L1 on B cell lymphoma in mice. Three shRNA vectors for mouse CD274 (PD-L1) were constructed and transiently transfected into 293T cells. RT-qPCR was used to validate the interference efficiency of CD274. The shRNA vector that interfere efficiently with CD274 expression was packaged by using lentivirus packaging system to generate shRNA lentivirus, and then transfected into A20 lymphoma cell line. The methyl thiazol terazolium (MTT) assay was used to detect proliferation after 48 h culture of CD274-sh A20 cells. Meanwhile, BALB/c mice were hypodermically infected with CD274-sh A20 cells. Infected mice were observed daily and assessed to visualize tumor by in vivo fluorescence imaging. The proliferation rate of CD274-sh A20 cells in vitro was significantly lower than that of A20 cells (P<0.05). The tumor size detected by in vivo fluorescence imaging showed a significant reduce in tumor bearing mice with CD274-sh compared with other tumor bearing mice. And the weight and size of tumor in CD274-sh group were also significantly reduced compared with other group (P<0.05). Moreover, the survival time of tumor bearing mice in CD274-sh group was longer than that of the PD-L1 high expression group. PD-L1 plays an important role in the incidence and the progression of lymphoma, and the shRNA-based PD-L1 knockdown can inhibit cell proliferation of A20 cells and partly suppress tumor growth.