The mouse Steap1 gene was replaced by human STEAP1 coding sequence in B-hSTEAP1 MC38 cells. Human STEAP1 is highly expressed on the surface of B-hSTEAP1 MC38 cells.

Gene targeting strategy for B-hSTEAP1 MC38 cells. The exogenous promoter and human STEAP1 coding sequence was inserted to replace part of murine exon 3. The insertion disrupts the endogenous murine Steap1 gene, resulting in a non-functional transcript.

STEAP1 expression analysis in B-hSTEAP1 MC38 cells by flow cytometry. Single cell suspensions from wild-type MC38 and B-hSTEAP1 MC38 #2-G02 cultures were stained with species-specific anti-STEAP1 antibody (in house). Human STEAP1 was detected on the surface of B-hSTEAP1 MC38 cells but not wild-type MC38 cells.

Subcutaneous homograft tumor growth of B-hSTEAP1 MC38 cells. B-hSTEAP1 MC38 cells (1x10⁶, 5x10⁶) were subcutaneously implanted into B-hCD3EDG mice (male and female, 7-8-week-old, n=5). 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-hSTEAP1 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.

Cell Line Inoculation Precautions:

The cell inoculation amount is between 1E6-5E6.

B-hSTEAP1 MC38 cells were subcutaneously transplanted into hCD3EDG mice (n=5), and on 10 days post inoculation, tumor cells were harvested and assessed for human STEAP1 expression by flow cytometry. As shown, human STEAP1 was highly expressed on the surface of tumor cells. Therefore, B-hSTEAP1 MC38 cells can be used for in vivo efficacy studies of novel STEAP1 therapeutics.