The mouse Ror1 gene was replaced by human ROR1 coding sequence in B-hROR1 MC38 cells. Human ROR1 is highly expressed on the surface of B-hROR1 MC38 cells.

Gene targeting strategy for B-hROR1 MC38 cells. The exogenous promoter and human ROR1 coding sequence was inserted to replace part of murine exon 3 and all of exon 4. The insertion disrupts the endogenous murine Ror1 gene, resulting in a non-functional transcript.

ROR1 expression analysis in B-hROR1 MC38 cells by flow cytometry. Single cell suspensions from wild-type MC38 and B-hROR1 MC38 cultures were stained with species-specific anti-ROR1 antibody. Human ROR1 was detected on the surface of B-hROR1 MC38 cells but not wild-type MC38 cells. The 1-G06 clone of B-hROR1 MC38 cells was used for in vivo experiments.

Subcutaneous homograft tumor growth of B-hROR1 MC38 cells. B-hROR1 MC38 cells (5x10⁵) and wild-type MC38 cells (5x10⁵) were subcutaneously implanted into C57BL/6N mice (female, 8-week-old, n=8). Tumor volume and body weight were measured twice a week. (A) Average tumor volume ± SEM. (B)  Body weight (Mean± SEM). Volume was expressed in mm³ using the formula: V=0.5 X long diameter X short diameter². As shown in panel A, B-hROR1 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.