Effect Of Energized Fusion Protein Anti-CD20(Fab)-LDM On Proliferation And DNA Damage Of Human Lymphoma Cell Line BJAB

Background and Objective Malignant lymphomas are a group of cancers in which cells of the lymphatic system become abnormal and start to grow uncontrollably. Lymphomas can be divided into two main types: Hodgkin’s and non-Hodgkin’s. In china, B-cell lymphomas comprise about70percent of all non-Hodgkin’s cases. Among B-cell-specific antigens, CD20is emerging as a promising target due to broadly expressed by B-cell malignancies and undergoing rapid internalization following antibody binding. Lidamycin(LDM) is one of the most potent antitumor antibiotic chromoproteins, and is composed of an apoprotein(LDP) and a chromophore(AE). Owing to its high potency cytotoxicity, LDM can be applied as a promising "warhead" in the production of antibody-based targeting therapeutics. In this study, we recombine anti-CD20(Fab) antibody with LDM by genetic engineering methods. The energized fusion protein anti-CD20(Fab)-LDM retained both target-binding activity of anti-CD20antibody and cytotoxic activity of LDM and targeted therapy for B-cell lymphoma.To investigate the growth inhibition effect and DNA damage of energized fusion protein anti-CD20(Fab)-LDM on BJAB cells in vitro.Methods The binding activity of fusion protein anti-CD20(Fab)-LDP to BJAB cells was studied by flow cytometry and confocal laser scanning microscope. MTT assay was used to study the energized fusion protein anti-CD20(Fab)-LDM on cell growth of BJAB cells. The comet assay was employed to detect DNA damage on BJAB cells. The cell growth cycle of BJAB was analyzed by FACS.Results The recombinant fusion protein anti-CD20(Fab)-LDP possessed an obvious target affinity toward BJAB cells. The energized fusion protein anti-CD20(Fab)-LDM showed obvious inhibition on proliferation, as well as induction potency of DNA damage on BJAB cells in vitro compared with lidamycin. BJAB cells treated with energized fusion protein anti-CD20(Fab)-LDM showed S arrest.Conclusion The energized fusion protein anti-CD20(Fab)-LDM could target binding with BJAB cells and obviously inhibit the proliferation of BJAB cells by inducing DNA damage and S phase arrest. Thus, CD20-targeted delivery of LDM is a specific and potent therapeutic strategy for B-lymphoid malignancies. In addition, the two-step approach could serve as a new technology platform for making a series of highly potent engineered antibody-based drugs.