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Updated: Jun 25, 2025
Targeted Antibody Blocking by a Dual-Functional Conjugate of Antigenic Peptide and Fc-III Mimetics DCAF
Published on: September 17, 2019
Efficient intracellular drug delivery by co-administration of two antibodies against cell adhesion molecule 1
Man Hagiyama1, Azusa Yoneshige1, Akihiro Wada1
1Department of Pathology, Faculty of Medicine, Kindai University, Osaka, Japan.
Abstract:
Cell adhesion molecule 1 (CADM1), a single-pass transmembrane protein, is involved in oncogenesis. We previously demonstrated the therapeutic efficacy of anti-CADM1 ectodomain monoclonal antibodies against mesothelioma; however, the underlying mechanism is unclear. In the present study, we explored the molecular behavior of anti-CADM1 antibodies in CADM1-expressing tumor cells. Sequencing analyses revealed that the anti-CADM1 chicken monoclonal antibodies 3E1 and 9D2 are IgY and IgM isotype antibodies, respectively. Co-administration of 3E1 and 9D2 altered the subcellular distribution of CADM1 from the detergent-soluble fraction to the detergent-resistant fraction in tumor cells. Using recombinant chicken-mouse chimeric antibodies that had been isotype-switched from IgG to IgM, we demonstrated that the combination of the variable region of 3E1 and the constant region of IgM was required for CADM1 relocation. Cytochemical studies showed that 3E1 colocalized with late endosomes/lysosomes after co-administration with 9D2, suggesting that the CADM1-antibody complex is internalized from the cell surface to intracellular compartments by lipid-raft mediated endocytosis. Finally, 3E1 was conjugated with the antimitotic agent monomethyl auristatin E (MMAE) via a cathepsin-cleavable linker. Co-administration of 3E1-monomethyl auristatin E and 9D2 suppressed the growth of multiple types of tumor cells, and this anti-tumor activity was confirmed in a syngeneic mouse model of melanoma. 3E1 and 9D2 are promising drug delivery vehicles for CADM1-expressing tumor cells.
Insights
Two monoclonal antibodies targeting cell adhesion molecule 1 (CADM1) relocate the protein to detergent-resistant fractions and facilitate targeted drug delivery. This combination therapy shows promise for treating CADM1-expressing tumors.
Area of Science:
- Oncology
- Immunology
- Molecular Biology
Background:
- Cell adhesion molecule 1 (CADM1) is implicated in oncogenesis.
- Previous studies showed therapeutic efficacy of anti-CADM1 antibodies against mesothelioma, but the mechanism was unclear.
Purpose of the Study:
- To investigate the molecular mechanisms of anti-CADM1 antibodies in tumor cells.
- To explore the potential of anti-CADM1 antibodies as drug delivery vehicles.
Main Methods:
- Sequencing analysis of anti-CADM1 chicken monoclonal antibodies (3E1: IgY, 9D2: IgM).
- Assessment of CADM1 subcellular distribution after antibody co-administration.
- Creation of isotype-switched chimeric antibodies to identify critical antibody regions.
- Cytochemical studies to track antibody-antigen complex internalization.
- Conjugation of 3E1 antibody with monomethyl auristatin E (MMAE).
- Evaluation of anti-tumor activity in vitro and in a syngeneic mouse melanoma model.
Main Results:
- Co-administration of 3E1 and 9D2 antibodies induced CADM1 relocation to detergent-resistant fractions.
- The variable region of 3E1 combined with the IgM constant region was essential for CADM1 relocation.
- The 3E1-CADM1 complex was internalized via lipid-raft mediated endocytosis to late endosomes/lysosomes.
- The 3E1-MMAE conjugate, in combination with 9D2, suppressed tumor cell growth.
- Anti-tumor activity was confirmed in a preclinical mouse model.
Conclusions:
- The combination of anti-CADM1 antibodies 3E1 and 9D2 alters CADM1 localization and facilitates targeted drug delivery.
- Anti-CADM1 antibodies, particularly 3E1 conjugated with MMAE and administered with 9D2, demonstrate significant anti-tumor potential.
- These antibodies represent promising drug delivery vehicles for CADM1-expressing tumors.
