A selective αvβ5 integrin antagonist hidden into the anophelin family protein cE5 from the malaria vector Anopheles gambiae

A RGD motif was identified in the N-terminal region of cE5, a potent salivary thrombin inhibitor from the African malaria vector Anopheles gambiae. A peptide (APQ30) encompassing the first 30 amino acids residues of the protein and including the RGD tripeptide was tested in cell adhesion assays and found to inhibit avb3 and avb5 mediated adhesion. A shorter peptide (APQ16), strongly conserved among members of the A. gambiae species complex and including only the first 16 residues, retained adhesion inhibitory properties, however with enhanced specificity toward avb5. In addition, migration and invasion assays showed its capacity to inhibit the invasiveness of the malignant cell lines HepG2 and MDA-MB231. Altogether our data point to APQ16 as a new promising candidate as theranostic agent.