Objectives:
Whilst a number of ADAM partners for α9β1 integrin have been reported, there is no published information on binding of αVβ6 to these proteins. The aim of this study was therefore to identify potential ADAM binding partners for the αVβ6 integrin.
Methods:
OSCC cell lines heterologously over-expressing the integrins αVβ6 (VB6) and α9β1 (A9) and their relevant null transfectants (C1 and NV) were subjected to flow cytometry to confirm integrin expression. Conventional cell adhesion assays using recombinant ADAMs were used to determine the capacity these cells to bind to ADAM proteins. Fibronectin (FN) was included as a positive control and function blocking antibodies were employed to confirm specificity.
Results:
A9 cells demonstrated adhesion to ADAM 9 (43.5% +/- 2.9) and 12 (57.8% +/- 5.2) at similar levels to FN but low adherence to ADAM 10 (3.6% +/- 5.1) was observed. VB6 cells adhered to ADAM 9 (40.1% +/- 13.4) and 12 (52.8% +/- 17.0) to a similar degree but also exhibited adherence to ADAM 10 (48.1% +/- 22.4). Null transfectant cell lines adhered to FN but showed minimal affinity for ADAM proteins.
Conclusions:
These results demonstrate for the first time that αVβ6 integrin can interact with ADAM proteins and, whilst the functional relevance of this is unclear, this may play an important role in the progression of oral cancer.
Acknowledgements: Yorkshire Cancer Research Grant No: S297 & the Royal College of Surgeons of England