Black Tea Polyphenol (Theaflavin) Downregulates MMP-2 in Human Melanoma Cell Line A375 by Involving Multiple Regulatory Molecules

Abstract

The tumor-inhibiting property of black tea polyphenol, theaflavin, is well documented. Matrix metalloproteinases (MMPs) play a pivotal role in tumor invasion through degradation of extracellular matrix (ECM). In the present study, we observed the effect of theaflavin on MMP-2, which is upregulated in most tumor types, and its regulatory molecules, in human melanoma cell line, A375. The treatment of theaflavin downregulated the gelatinolytic activity, mRNA and protein expression of MMP-2. It reduced the mRNA and protein expression of membrane type-1 MMP (MT1-MMP) and induced mRNA and protein expression of tissue inhibitor of MMP-2 (TIMP-2), suggesting theaflavin's inhibitory effect on MMP-2 activation. Theaflavin reduced the binding of A375 cell to ECM ligands demonstrating that theaflavin treatment hinders cell-ECM adhesion, cell motility, and integrin-mediated MMP-2 activation. Theaflavin treatment inhibited the protein expression FAK EGFR and ERK, suggesting that, theaflavin treatment downregulates the molecules participating in MMP-2 secretion and regulation. The downregulation of NFchiB suggests downregulation of MMP-2 transactivation. Theaflavin also reduced the tumor volume in syngenic black mice. Thus, we report that theaflavin causes an inhibition of the expression and activity of pro-MMP-2 by a process involving multiple regulatory molecules in human melanoma cells, A375.

Effect of Black Tea Polyphenol on Cell-ECM Interaction and MMP

“…The MMPs adsorbed was released in Lammeli's buffer without B-mercaptoethanol and subjected to zymography. Zymography was also done with human salivary MMPs incubating it with black tea extract and theaflavin separately (in vitro) for 30 mins at 37˚C [11] [17]. We also assayed salivary MMP in vivo.…”

“…Theaflavin downregulates MMP-2 and MT1-MMP expression and activity and upregulate TIMP-2 levels in A375 human melanoma cells has been reported [17]. Binding of epidermal growth factor receptor (EGFR), a member of erbB family of tyrosine kinase receptors, to its ligands leads to phosphorylation of receptor tyrosine kinases including focal adhesion kinase (FAK) and subsequent activation of signal transduction pathways involved in regulating cellular proliferation, differentiation and survival [18] [19].…”

“…Integrin receptors play important roles in cell anchoring and are critically involved in multiple signal transduction cascades [22] [23]. Theaflavin and its derivatives have been reported to reduce adhesion of MO4 cells to laminin and adhesion of A375 melanoma cells fibronectin, vitronectin and laminin via integrin receptors [17] [24].…”

“…Theaflavin prevents IL-6 and ICAM-1 expression through blockade of NF-κB and MAPK signalling pathways in bone marrow-derived macrophages [31]. Theaflavin and black tea polyphenols have been reported to downregulate levels of FAK and ERK in A375 melanoma cells and inhibit FAK, ERK 1/2 and c-Jun [17] [32]. Theaflavins prevent inflammation in bowel diseases by inhibition of integrin linked kinases (ILK) and NF-κB signalling pathways [33].…”

Camellia sinensis (Tea) in the Prevention of UV-Induced Carcinogenesis: A Mechanistic Overview

“…Studies with cultured human melanoma cell line A375 have shown that thea fl avin downregulates MMP-2 by affecting multiple regulatory molecules like FAK, EGFR and ERK [ 76 ] . Studies with arti fi cial skin composed of cultured keratinocytes on a collagen matrix populated with fi broblasts has shown that treatment with EGCG prior to UVA irradiation decreases the level of MMPs production and to increase TIMP-1 expression level.…”