| Immunotherapy with tumor-associated antigens (TAAs) is a potentially powerful approach to
eradicate tumor cells. The receptor tyrosine kinase-like orphan receptor 1 (ROR1) plays a crucial role for survival
of tumor cells and is overexpressed in various malignancies. In the present study, we developed a syngeneic
mouse tumor model to assess anti-tumor effect of mouse ROR1 specific polyclonal antibody (pAb) in vivo.
Materials and methods: Mouse ROR1 specific antibody was produced in rabbit using recombinant ROR1 protein.
Tow mouse tumor cell lines, (4T1 and CT26), were transfected with full length mouse ROR1 construct and stable
clones were selected and characterized by immunocytochemistry, Western blot and flow cytometry. In vitro and
in vivo anti-tumor activities of anti-ROR1 antibody were assessed by XTT and syngeneic BALB/c mouse model,
respectively.
Results: We successfully established two mouse ROR1-overexpressing tumor cell lines. The in vitro results indicate
that the ROR1pAb did not significantly inhibit growth of ROR1+ cell lines. One of these cell lines (CT26-
ROR1) was implanted in syngeneic BALB/c mice to assess anti-ROR1 tumor inhibitory activity in vivo. The
tumor size was significantly reduced in mice treated with ROR1 specific pAb.
Conclusion: Our results demonstrated for the first time tumor inhibitory effect of mouse ROR1 specific antibody
in a syngeneic mouse tumor model. This model is a promising tool for preclinical assessment of ROR1 therapeutics
and investigation of the underling molecular mechanisms. |