Related Experiment Video
Updated: Jun 17, 2026
A Cancer Cell Spheroid Assay to Assess Invasion in a 3D Setting
Published on: November 20, 2015
Screening of EWI-2-Derived Peptides for Targeting Tetraspanin CD81 and Their Effect on Cancer Cell Migration
Thanawat Suwatthanarak1,2,3, Kei Usuba1, Kotomi Kuroha1
1Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1-S1-24 O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
Abstract:
CD81, a transmembrane protein belonging to the tetraspanin family, has recently been suggested as a therapeutic target for cancers. Here, we screened peptides that bind to the tetraspanin CD81 protein, and evaluated their inhibitory activity in cancer cell migration. To screen for CD81-binding peptides (CD81-BP), a peptide array membrane was prepared from the amino acid sequence of the EWI-2 protein, a major partner of CD81, before binding to fluorescently labeled CD81. As a result, four candidate CD81-BPs were identified and characterized. In particular, the CFMKRLRK peptide (called P152 in this study) was found to be the best candidate that preferentially binds to the extracellular loop of CD81, with an estimated dissociation constant of 0.91 µM. Since CD81 was reported to promote cancer cell migration, an initial step in metastasis, the Boyden chamber assay, was next performed to assess the effect of CD81-BP candidates on the migration of MDA-MB-231 human breast cancer cells. Interestingly, our result indicated that P152 could suppress MDA-MB-231 cell migration at the level comparable to that of an anti-human CD81 antibody (5A6). Thus, we propose these CD81-BPs with the anti-migration property against cancer cells for the development of novel therapeutic strategies.
Insights
Researchers identified novel CD81-binding peptides (CD81-BPs) that inhibit cancer cell migration. One peptide, P152, effectively suppressed breast cancer cell movement, suggesting potential for new cancer therapies targeting CD81.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- CD81, a tetraspanin protein, is implicated in cancer progression and metastasis.
- Targeting CD81 presents a potential therapeutic strategy for various cancers.
Purpose of the Study:
- To screen for peptides that bind to CD81 (CD81-binding peptides, CD81-BPs).
- To evaluate the efficacy of identified CD81-BPs in inhibiting cancer cell migration.
Main Methods:
- Peptide array screening using fluorescently labeled CD81.
- Characterization of CD81-binding peptides, including binding affinity determination (dissociation constant).
- Boyden chamber assay to assess the effect of CD81-BPs on MDA-MB-231 breast cancer cell migration.
Main Results:
- Four candidate CD81-BPs were identified.
- The peptide P152 demonstrated preferential binding to CD81's extracellular loop with a dissociation constant of 0.91 µM.
- P152 significantly suppressed MDA-MB-231 cell migration, comparable to an anti-CD81 antibody.
Conclusions:
- CD81-binding peptides, particularly P152, exhibit anti-migratory properties against cancer cells.
- These CD81-BPs hold promise for developing novel therapeutic strategies targeting CD81 in cancer treatment.
