Inhibiting and invasive self-renewal effect of PTPRZ 1 monoclonal antibody on glioma stem cells

To prepare a monoclonal antibody targeting protein tyrosine phosphatase receptor-type Z polypeptide1（PTPRZ 1）, to investigate the potential to disrupt the pleiotrophin（PTN）-PTPRZ 1 paracrine signaling axis, and to evaluate the inhibitory effects on the self-renewal, migration, and invasion of glioma stem cells.

The extracellular domain of PTPRZ 1（amino acids 26-300）served as the antigen to immunize female BALB/c mice aged 8 to 10 weeks. Following a 2-week immunization period, serum samples were collected via tail vein puncture, centrifuged to separate, and the antibody titer was quantified by ELISA. Subsequently, B cell fusion and positive hybridoma cell selection were conducted to isolate murine monoclonal antibodies targeting PTPRZ 1. Antibody clones with the highest affinity were identified through specialized affinity assays. Human glioma stem cells were infected with sgRNA-PTPRZ 1 lentivirus for PTPRZ 1 gene silencing, and the changes in the expression of PTPRZ 1 at mRNA level were analyzed using RT-qPCR. Western blotting was employed to confirm the antibodies' specificity for PTPRZ 1. The experiments on the functions and mechanisms of glioma stem cells were divided into 4 groups: the control group, the human recombinant PTN-treated group, the mouse anti-PTPRZ 1 antibody（clone 2F10）-treated group, and the combination treatment of human recombinant PTN and mouse anti-PTPRZ 1 antibody（clone 2F10）group. The expression of PTPRZ 1 downstream signaling pathways in glioma stem cells was examined via Western blotting. Clonogenic, migration, and invasion assays were utilized to determine the effects on self-renewal, migration, and invasion capabilities of glioma stem cells.

Five murine monoclonal antibodies targeting PTPRZ 1 were successfully generated, with clone 2F10 displaying the highest binding affinity that was found to be effective for detecting PTPRZ 1 protein expression. Compared with the control group, treatment with human recombinant PTN significantly increased ERK phosphorylation downstream of PTPRZ 1 in glioma stem cells, thereby enhancing their self-renewal（P<0.01）, migration（P<0.01）, and invasion（P<0.05）. The application of mouse anti-PTPRZ 1 antibody（2F10）effectively blocked PTN-mediated ERK phosphorylation, resulting in a significant reduction in self-renewal（P<0.01）, migration（P<0.01）, and invasion（P<0.05）abilities of glioma stem cells.

The mouse anti-PTPRZ 1 monoclonal antibody, clone 2F10, efficiently targets and recognizes the PTPRZ 1 protein in glioma stem cells, impeding PTN-mediated processes essential for their self-renewal, migration, and invasion.