Over the last decade, we have identified a series of molecules that are differentially expressed by cancer cells than their normal cell counterparts. One group of molecules has particularly attracted our interest: the cell-surface ectopeptidases in the dipeptidyl peptidase IV (DPPIV) family. This group includes DPPIV and fibroblast activation protein alpha (FAP-alpha). The expression of DPPIV is often extinguished by cancer cells, suggesting that this protein may have tumor suppressor activity. For instance, DPPIV is expressed by normal melanocytes, but expression is lost upon transformation to melanoma.
We have shown that re-expression of DPPIV in melanoma can reverse the malignant phenotype. We are presently working to understand the function of DPPIV and its family member FAP-alpha in cell growth, differentiation, and malignant transformation.
