Analysis of ADAM9 regulation and function in vestibular schwannoma primary cells

ObjectiveRecently, we described a disintegrin and metalloproteinase 9 (ADAM9) overexpression by Schwann cells of vestibular schwannoma (VS) and suggested that it might be a marker for VS tumor growth and invasiveness. This research note provides additional data utilizing a small cohort of VS primary cultures and tissue samples. We examined whether reconstitution of Merlin expression in VS cells regulates ADAM9 protein expression and performed lentiviral ADAM9 knock down to investigate possible effects on VS cells numbers. Moreover, the co-localization of ADAM9 and Integrins alpha 6 and alpha 2 beta 1, respectively, was examined by immunofluorescence double staining.ResultsADAM9 expression was not regulated by Merlin in VS. However, ADAM9 knock down led to 58% reduction in cell numbers in VS primary cell cultures (p<0.0001). While ADAM9 and Integrin <alpha>2 beta 1 were co-localized in only 22% (2 of 9) of VS, ADAM9 and Integrin alpha 6 were co-localized in 91% (10 of 11) of VS. Therefore, we provide first observations on possible regulatory functions of ADAM9 expression in VS.