Melanoma metastasis requires migration and invasion of the malignant tumour cells driven by proteolytic remodelling of the extracellular matrix (ECM) executed by matrix metalloproteinases (MMPs), particularly MMP-2 and MMP-9.
We found that silencing <i>Myo7a</i> by means of RNAi inhibited melanoma cell growth through upregulation of cell cycle regulator p21 (also known as CDKN1A) and suppressed melanoma cell migration and invasion through downregulation of RhoGDI2 (also known as ARHGDIB) and MMP9.
The bioactivity studies demonstrated that most of these compounds could upregulate the expression of matrix metalloproteinase-9 (MMP-9, extracellular matrix proteins associated with tumor migration) in murine melanoma B16 cells in a similar manner to the natural ganglioside monosialodihexosylganglioside (GM3), which highlights the potential use of these neoglycosphingolipids as inhibitors of tumor migration.
The melanoma cell lines showed different growth patterns in the brain, and these differences were associated with differences in expression of the angiogenic factors VEGF-A and IL-8 and the matrix metalloproteinases MMP-2 and MMP-9.
We conclude that OPN signaling is involved in macrophage recruitment into tumor, and our results emphasize the potential role of macrophage in modulation of tumor microenvironment via secretion of OPN, PGE2 and MMP-9, which trigger angiogenesis and melanoma growth.
Here, we analyzed the expression of RECK, TIMP1, TIMP2, TIMP3, MT1MMP, MMP2, and MMP9 in two publicly available melanoma microarray datasets and in a panel of human melanoma cell lines.
Immunohistochemical analysis of pSTAT3, SOCS3, matrix metalloproteinase (MMP)-2, and MMP-9 expression was performed on 90 primary melanomas and 43 common melanocytic nevi specimens.
Moreover, our data showed that overexpression of ING4 inhibited melanoma cell invasion by 43% compared with the control (P = 0.006, t-test) and ING4-overexpressing melanoma cells showed significantly reduced activity of matrix metalloproteinase (MMP)-2 and MMP-9.
We tested seven polymorphisms within the MMP-9 gene in 1002 patients with melanoma in order to evaluate germline genetic variants and their association with progression and known risk factors of melanoma.
From these results we conclude that an altered responsiveness of gelatinase B and TIMP-1 to induction by similar agents is associated with disease progression in human melanoma and that this altered responsiveness can have consequences to the aggressive nature of the disease.