DIR13 Antibody

Biological Role of CD13

CD13 (Aminopeptidase N) is a transmembrane glycoprotein expressed on myeloid cells, epithelial cells, and certain tumors . It functions as a metalloprotease involved in peptide metabolism and cell signaling. Notably, CD13 is overexpressed in cancers such as fibrosarcoma, myeloma, and hepatocellular carcinoma, making it a therapeutic target .

Functional Properties

Data derived from preclinical studies on fibrosarcoma xenografts .

Antibody-Drug Conjugates (ADCs)

• MI130110: Conjugates the anti-CD13 antibody TEA1/8 with the cytotoxic agent PM050489, achieving selective tumor cell death via microtubule disruption .

  • Mechanism: Internalized CD13-ADC complexes release PM050489, inducing mitotic catastrophe (G2/M arrest, multipolar spindles) .

  • Selectivity: No activity observed in CD13-negative cells (e.g., Raji lymphoma) .

Diagnostic and Research Tools

• Anti-CD13 Antibodies: Used in flow cytometry (e.g., AF3815 antibody detects CD13 on U937 histiocytic lymphoma cells) and immunohistochemistry (IHC) for tumor stratification .

In Vitro Efficacy

• Proliferation Assays: MI130110 showed potent anti-proliferative effects on CD13+ HT1080 fibrosarcoma cells (IC50: 0.2 nM) vs. no effect on CD13- Raji cells .

• Apoptosis/Necrosis: Induces annexin V/PI-positive cell death in CD13+ lines (e.g., U937, HT1080) .

In Vivo Performance

• Xenograft Models: MI130110 achieved complete tumor remission in 80% of HT1080 fibrosarcoma-bearing mice at 20 mg/kg .

• Safety Profile: No toxicity or weight loss observed in treated animals .

Comparative Analysis of CD13 Antibodies

Challenges and Future Directions

• Tumor Heterogeneity: CD13 expression varies across cancers (e.g., overexpressed in 30% of hepatocellular carcinomas) .

• Resistance Mechanisms: Potential shedding of CD13 extracellular domains may reduce ADC efficacy .

• Next-Generation ADCs: Engineering non-cleavable linkers (e.g., MI130110’s maleimide-PEG) enhances serum stability and payload delivery .