TGF-β1 + EGF-Initiated Invasive Potential in Transformed Human Keratinocytes Is Coupled to a Plasmin/MMP-10/MMP-1–Dependent Collagen Remodeling Axis: Role for PAI-1

Abstract

The phenotypic switching called epithelial-to-mesenchymal transition is frequently associated with epithelial tumor cell progression from a comparatively benign to an aggressive, invasive malignancy. Coincident with the emergence of such cellular plasticity is an altered response to transforming growth factor-B (TGF-B) as well as epidermal growth factor (EGF) receptor amplification. TGF-B in the tumor microenvironment promotes invasive traits largely through reprogramming gene expression, which paradoxically supports matrix-disruptive as well as stabilizing processes. ras-transformed HaCaT II-4 keratinocytes undergo phenotypic changes typical of epithelial-to-mesenchymal transition, acquire a collagenolytic phenotype, and effectively invade collagen type 1 gels as a consequence of TGF-B1 + EGF stimulation in a three-dimensional physiologically relevant model system that monitors collagen remodeling. Enhanced collagen degradation was coupled to a significant increase in matrix metalloproteinase (MMP)-10 expression and involved a proteolytic axis composed of plasmin, MMP-10, and MMP-1. Neutralization of any one component in this cascade inhibited collagen gel lysis. Similarly, addition of plasminogen activator inhibitor type 1 (SERPINE1) blocked collagen degradation as well as the conversion of both proMMP-10 and proMMP-1 to their catalytically active forms. This study therefore identifies an important mechanism in TGF-B1 + EGF-initiated collagen remodeling by transformed human keratinocytes and proposes a crucial upstream role for plasminogen activator inhibitor type 1-dependent regulation in this event. [Cancer Res 2009;69(9):4081-91]

SERPINE1: A Molecular Switch in the Proliferation-Migration Dichotomy in Wound-“Activated” Keratinocytes

“…2,6,[13][14][15] PAI-1 is induced in migratory cells regardless of lineage, as well as in epithelial cells undergoing epithelial-to-mesenchymal (EMT)-like transitions upon expression of the E-cadherin transcriptional repressors Snail, Slug, or E47. 16,17 Keratinocytes and other epithelia undergo at least a partial EMT following wounding or directional migration [18][19][20] with up-regulation of uPA, the uPA cell surface receptor (uPAR), and PAI-1 at the migratory front. 6 Motile cells focalize both uPA (via interaction with uPAR) and PAI-1 (upon binding to uPA/ uPAR) to the leading edge, where they function in the interrelated events of matrix restructuring and migration.…”

Human matrix metalloproteinases: An ubiquitarian class of enzymes involved in several pathological processes

“…Cancer is a pathology wherein a contribution of the three stromelysins has been described quite extensively, even though with divergent molecular mechanisms (Gill et al, 2004;McCawley et al, 2004;Wilkins-Port et al, 2009). Other pathologies, for which a contribution from at least of one member of this family has been reported, mainly include cardiovascular, degenerative and auto-immune diseases.…”

“…MMP-10 up-regulation in early phases of skin tumor growth is stimulated by TGF-b and EGF: the resulting high collagenolytic activity correlates with invasiveness (Wilkins-Port et al, 2009). Increased levels of MMP-10 have been also found in lung cancer (Frederick et al, 2008).…”

Transforming growth factor-β1 induces invasion ability of HSC-4 human oral squamous cell carcinoma cells through the Slug/Wnt-5b/MMP-10 signalling axis

“…In addition, Kumawat et al (36) reported that TGF-b1 induced the expression of Wnt-5a, but not Wnt-5b, in airway smooth muscle cells. There are also a few reports that demonstrate the upregulation of MMP-10 expression during TGF-b1-induced EMT (43,44). TGF-b1 plus EGF stimulation induces expression of MMP-10 and MMP-1 in HaCaT II-4 keratinocytes and promotes the invasion ability of cells growing on collagen type I gels (43), presumably through enhanced collagen degradation.…”

“…There are also a few reports that demonstrate the upregulation of MMP-10 expression during TGF-b1-induced EMT (43,44). TGF-b1 plus EGF stimulation induces expression of MMP-10 and MMP-1 in HaCaT II-4 keratinocytes and promotes the invasion ability of cells growing on collagen type I gels (43), presumably through enhanced collagen degradation. Another report showed that the expression of MMP-10 is upregulated by TGF-b through myocyte enhancer factor 2A in mouse and human mammary epithelial cells (NMuMG and MCF10A, respectively) (44).…”