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Interaction between CD44 and osteopontin as a potential basis for metastasis formation
G F Weber1, S Ashkar, H Cantor
1Dana-Farber Cancer Institute, Division of Immunopathology, Boston, MA 02115, USA.
Proceedings of the Association of American Physicians
|January 1, 1997
Summary
The cytokine osteopontin binds to CD44, a cell surface molecule. This interaction may drive tumor cell migration and metastasis formation in cancer.
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Research
Background:
- Malignant growth involves oncogene activation, telomerase activity, and CD44 splice variant expression.
- The role of CD44 in tumor cell homing and tissue colonization is not fully understood.
Purpose of the Study:
- To identify ligands for CD44 and elucidate their role in cancer progression.
- To investigate the interaction between osteopontin and CD44 and its functional consequences.
Main Methods:
- Investigated the binding of osteopontin to CD44 using various assays, including antibody inhibition and competition studies.
- Assessed the functional effects of osteopontin-CD44 interaction on cell migration (chemotaxis) and attachment.
- Examined the role of osteopontin presentation (soluble vs. immobilized) on cellular responses.
Main Results:
- Identified osteopontin as a specific, dose-dependent ligand for CD44.
- Osteopontin binding to CD44 mediated cell chemotaxis or attachment, depending on osteopontin's form.
- CD44 binding to hyaluronate mediated aggregation or attachment but not chemotaxis.
- The co-occurrence of osteopontin secretion and CD44v expression in malignancy links these events to tumor cell migration.
Conclusions:
- Osteopontin is a functional ligand for CD44, mediating cell migration and attachment.
- The interaction between osteopontin and CD44 provides a mechanism for tumor cell homing to specific metastatic sites.
- Targeting the osteopontin-CD44 pathway may offer therapeutic strategies for inhibiting cancer metastasis.