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  • Integrin alpha3beta1 potentiates TGFbeta-mediated induction of MMP-9 in immortalized keratinocytes.

Integrin alpha3beta1 potentiates TGFbeta-mediated induction of MMP-9 in immortalized keratinocytes.

The Journal of investigative dermatology (2007-09-01)
John M Lamar, Vandana Iyer, C Michael DiPersio
ABSTRACT

Transforming growth factor-beta (TGFbeta) signaling pathways regulate a number of keratinocyte functions during epidermal carcinogenesis and wound healing, including proliferation, survival, and migration. TGFbeta can induce expression of the matrix metalloproteinase-9 (MMP-9), which has critical roles in promoting extracellular matrix remodeling and angiogenesis during tumorigenesis and tissue repair. Integrin alpha3beta1 is a cell adhesion receptor for laminin-332/laminin-5 with important roles in the survival and motility of epidermal keratinocytes. We previously reported that alpha3beta1 induces the expression of MMP-9 in immortalized keratinocytes. In this study, we show that endogenous TGFbeta is required for maximal MMP-9 expression, and that alpha3beta1 is required for full induction of MMP-9 protein and mRNA in response to TGFbeta. This regulation was not observed in non-immortalized, primary keratinocytes, indicating that coordinate regulation of MMP-9 by alpha3beta1 and TGFbeta is a property of immortalized cells. Alpha3beta1 did not regulate endogenous TGFbeta gene expression, TGFbeta bioavailability, or TGFbeta-Smad signaling. However, the combined inductive effects of TGFbeta and alpha3beta1 on MMP-9 were suppressed by a Src family kinase (SFK) inhibitor, indicating involvement of a SFK pathway. These findings provide early evidence of a role for alpha3beta1 in augmenting TGFbeta-mediated induction of MMP-9 in immortalized or transformed keratinocytes during skin carcinogenesis.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
REDTaq® ReadyMix PCR Reaction Mix, Complete PCR reagent with standard Taq DNA Polymerase and inert dye
Sigma-Aldrich
Gelatin-Agarose, saline suspension
Sigma-Aldrich
Gelatin, tested according to Ph. Eur.