Anti-DR5 mAb inhibits proliferation of human fibroblast-like synovial cells and reduces their cytokine secretion in vitro

Abstract

Minping Zhang,1,2,* Chunyan Shi,1,* Chun Xia,3 Jin Yang,1 Xingyang Niu,1 Guohong Zhuang,1 Ping Yin4 1Organ Transplantation Institute, Anti-Cancer Research Center, Medical College, Xiamen University, Xiamen, 2The Department of Pharmacy, First Hospital, Nanping, 3The Department of Orthopaedics, 4The Department of Pathology, Xiamen Zhongshan Hospital, Xiamen University, Xiamen, Fujian, People’s Republic of China *These authors contributed equally to this work Background: We have previously reported that anti-death receptor 5 (DR5) monoclonal antibody (mAb) is therapeutically effective in the treatment of rheumatoid arthritis (RA) in a collagen-induced arthritis rat model. However, the molecular mechanism and the effect of anti-DR5 mAb on proapoptotic genes and cytokine secretion in the human fibroblast-like synovial cells (FLS) requires further clarification. This study may provide new evidence for the application of anti-DR5 mAb as a treatment for RA.Methods: Human FLS were isolated from patients with RA and were treated with anti-DR5 mAb. An MTT assay and flow cytometry were used to detect the induction of apoptosis in vitro. Cytokine secretion by the FLS was detected using the enzyme-linked immunosorbent assay. The mRNA expression was assessed by reverse transcription polymerase chain reaction, and the protein expression was analyzed by Western blot. The apoptotic pathway was investigated further using a caspase inhibition assay.Results: Anti-DR5 mAb-induced apoptosis in human RA FLS in vitro. The protein expressions of caspase-8, -3, and -9 were decreased in human anti-DR5 mAb-treated FLS in a dose-dependent manner through exposure to a caspase inhibitor, indicating that anti-DR5 mAb induction of apoptosis is through the caspase pathway. Decreased levels of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) were detected after treatment with anti-DR5 mAb in vitro.Conclusion: Anti-DR5 mAb may induce apoptosis in human FLS through the caspase pathway and through decreased secretions of TNF-α and IFN-γ. Keywords: death receptor 5, rheumatoid arthritis, apoptosis