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Xiao Yang, Dong Fang, Ming Li, Jiayi Chen, Yuanbo Cheng, Jianming Luo
(Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China (mainland))
Med Sci Monit 2021; 27:e929431
Enzymatically inactive chitinase-like protein CHI3L1 is overexpressed in diffuse large B cell lymphoma (DLBCL) patients with PD-L1 imbalance and promotes tumor progression in the microenvironment. Based on this, we investigated how CHI3L1 acts on the proliferation and apoptosis of DLBCL and whether there is a synergy of CHI3L1 in combination with anti-PD-L1 antibodies in vivo.
MATERIAL AND METHODS: CHI3L1 was detected by quantitative real-time PCR (RT-PCR) and western blot (WB) in B-lymphoma cell lines. CHI3L1 interference plasmids were constructed, and the levels of proliferation, cell cycle, apoptosis, and cell survival were examined in vitro in B-lymphoma cell lines and in vivo in a murine xenograft model by RT-PCR, WB, CCK-8, and flow cytometry.
RESULTS: CHI3L1 was significantly expressed in SU-DHL-4 cells. CHI3L1-interfered RNA ShRNA-CHI3L1-1 was chosen to be used in the next experiment because it had a better interference effect. Dampened cell proliferation level, arrested cell cycle, reduced protein expressions of cyclin D1 and cyclin D2, and promoted cell apoptosis level were observed after SU-DHL-4 was transfected with ShRNA-CHI3L1-1. Furthermore, we also noticed increased expression of Bcl-2, decreased expressions of bax, cleaved caspase 3 and cleaved PARP, promoted cell survival-related protein p53, and reduced survivin.
CONCLUSIONS: This study demonstrated that knockdown of CHI3L1 inhibits cancer cell proliferation by regulating cell cycles, promotes cancer cell apoptosis, and enhances the pro-apoptotic effect of anti-PD-L1 antibody both in vivo and in vitro in DLBCL.