• NECTIN4 (nectin cell adhesion molecule 4) is a cell adhesion molecule belonging to the nectin and nectin-like family. It is abundantly present in normal embryonic and fetal tissues but shows very low expression in healthy adult tissues. NECTIN4 is overexpressed in many tumor cells, where it promotes tumor growth and proliferation. Solid tumors with high NECTIN4 expression include bladder cancer, pancreatic cancer, triple-negative breast cancer, non-small cell lung cancer, gastric cancer, esophageal cancer, ovarian cancer, and several others. Studies have revealed that NECTIN4 activates the PI3K/Akt pathway, thereby promoting tumor cell proliferation, differentiation, migration, and invasion. It is considered to play a significant role in cancer development and metastasis.
• The exons 2-6 of mouse Nectin4 gene that encode the extracellular domain were replaced by human counterparts in B-NDG hNECTIN4 mice. The genomic region of mouse Nectin4 gene that encodes signal peptide, transmembrane domain and cytoplasmic portion was retained. The promoter, 5’UTR and 3’UTR region of the mouse gene were also retained. The NECTIN4 expression is driven by endogenous mouse Nectin4 promoter, while mouse Nectin4 gene transcription and translation will be disrupted.
• Mouse Nectin4 mRNA was only detectable in wild-type mice. Human NECTIN4 mRNA was exclusively detectable in homozygous B-NDG hNECTIN4 mice but not in wild-type mice. Human NECTIN4 was only detectable in stomach of homozygous B-hNECTIN4 mice but not in wild-type mice.
• Application: B-NDG hNECTIN4 mice enable in vivo efficacy and safety evaluation of NECTIN4-targeted therapeutics (e.g., ADCs, bispecifics, and cell therapies) with on-target/off-tumor assessment.

Gene targeting strategy for B-NDG hNECTIN4 mice. The exons 2-6 of mouse Nectin4 gene that encode the extracellular domain were replaced by human counterparts in B-NDG hNECTIN4 mice. The genomic region of mouse Nectin4 gene that encodes signal peptide, transmembrane domain and cytoplasmic portion was retained. The promoter, 5’UTR and 3’UTR region of the mouse gene were also retained. The NECTIN4 expression is driven by endogenous mouse Nectin4 promoter, while mouse Nectin4 gene transcription and translation will be disrupted.

Strain specific analysis of NECTIN4 mRNA expression in wild-type B-NDG mice and homozygous B-NDG hNECTIN4 mice by RT-PCR. Stomach tissue was collected from wild-type B-NDG mice (+/+) and homozygous B-NDG hNECTIN4 mice (H/H). Mouse Nectin4 mRNA was only detectable in wild-type B-NDG mice. Human NECTIN4 mRNA was exclusively detectable in homozygous B-NDG hNECTIN4 mice but not in wild-type B-NDG mice.

Strain specific NECTIN4 expression analysis in wild-type B-NDG mice (+/+) and homozygous humanized B-NDG hNECTIN4 mice (H/H) by western blot. The tissues of lung, stomach, bladder, brain and small intestine were collected from wild-type B-NDG mice and homozygous B-NDG hNECTIN4 mice (female, 10-week-old, n=1). Protein expression was analyzed with anti human NECTIN4 antibody (abcam, ab192033) by western blot. Human NECTIN4 was only detectable in stomach of B-NDG hNECTIN4 mice, but not in wild-type B-NDG mice.