The mouse Her3 gene was replaced by human HER3 coding sequence in B-hHER3 MC38 cells. Human HER3 is highly expressed on the surface of B-hHER3 MC38 cells.

Gene targeting strategy for B-hHER3 MC38 cells. The exogenous promoter and human HER3 coding sequence was inserted to replace part of murine exon 2 and all of exons 3-7. The insertion disrupts the endogenous murine HER3 gene, resulting in a non-functional transcript.

HER3 expression analysis in B-hHER3 MC38 cells by flow cytometry. Single cell suspensions from wild-type MC38 and B-hHER3 MC38 cultures were stained with species-specific anti-HER3 antibody. Human HER3 was detected on the surface of B-hHER3 MC38 cells but not wild-type MC38 cells. The 2-G07 clone of B-hHER3 MC38 cells was used for in vivo tumor growth assays.

Subcutaneous homograft tumor growth of B-hHER3 MC38 cells. B-hHER3 MC38 cells (5x10⁶) and wild-type MC38 cells (5x10⁵) were subcutaneously implanted into C57BL/6 mice (female, 7-8-week-old, n=6). 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-hHER3 MC38 cells were able to form tumors in vivo and can be used for efficacy studies.

B-hHER3 MC38 tumor growth of individual mice. B-hHER3 MC38 cells (5x10⁶) and wild-type MC38 cells (5x10⁵) were subcutaneously implanted into C57BL/6 mice (female, 7-8-week-old, n=6). As shown in panel, B-hHER3 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.