MT1-MMP dependent repression of the tumor suppressor SPRY4 contributes to MT1-MMP driven melanoma cell motility

Abstract

Metastatic melanoma is the deadliest of all skin cancers. Despite progress in diagnostics and treatment of melanoma, the prognosis for metastatic patients remains poor. We previously showed that Membrane-type 1 Matrix Metalloproteinase (MT1-MMP) is one of the drivers of melanoma metastasis. Classically, MT1-MMP regulates a verity of cellular functions including cell-to-cell interaction and cell-to-matrix communication. Recently, MT1-MMP has been found to also modulate gene expression. To specifically assess MT1-MMP dependent gene regulation in melanoma, microarray gene expression analysis was performed in a melanoma cell line whose metastatic properties depend on the activity of MT1-MMP. We identified the tumor suppressor gene SPRY4 as a new transcriptional target of MT1-MMP that is negatively regulated by the protease. Knockdown of MT1-MMP enhances SPRY4 expression at the mRNA and protein level. SPRY4 expression inversely correlates with that of MT1-MMP in melanoma samples and importantly, correlates with melanoma patient survival. SPRY4 modulates MT1-MMP dependent cell migration such that inhibition of SPRY4 rescues cell migration that has been impaired by MT1-MMP knock down. MT1-MMP decreases SPRY4 in part through an MMP2/RAC1 axis we previously show promotes cell motility downstream of MT1-MMP. These results identify the tumor suppressor SPRY4 as a novel molecular effector of MT1-MMP affecting melanoma cell motility.

The thiirane-based selective MT1-MMP/MMP2 inhibitor ND-322 reduces melanoma tumor growth and delays metastatic dissemination

“…We have previously shown that melanoma cell growth is in part controlled by MT1-MMP[14], whereas cell migration and invasion is a function of an MT1-MMP/MMP2 dependent pathway[12, 13]. Given that ND-322 behaves as a suitable MT1-MMP and MMP2 dual inhibitor, we sought to determine whether ND-322 could hinder these cell functions.…”

“…We also showed that MT1-MMP is required for melanoma metastasis[12]. MT1-MMP therefore acts as an oncogene in melanoma and allows for tumor cells to escape to other organs in part by promoting invasion and migration via an MT1-MMP/MMP2 signaling pathway[12, 13]. Hence, blockade of MT1-MMP/MMP2 may represent an effective means to prevent/inhibit metastatic melanoma.…”

“…shRNAs against human MT1-MMP (TRCN0000050855) and MMP2 (TRCN0000051526) were purchased from Sigma and were previously described[12, 13]. The primary melanoma cells line WM115, the syngeneic metastatic WM266–4, and the metastatic melanoma cell lines V2387 and K457 were originally purchased from ATCC or a gift or Dr. Marianne Broome Powell (Stanford University, Stanford, CA).…”

“…Cell seeding, collection of protein and Western blot methods were as previously described[12, 13]. Membranes were probed with the following antibodies: anti-MT1-MMP (Millipore, LEM-2/15.8); anti–β-actin (Santa Cruz Biotechnology, CA).…”

“…We have demonstrated that MT1-MMP increases as melanoma progress toward a more invasive, metastatic phenotype and that its expression inversely correlates with melanoma patient survival[12]. MT1-MMP contributes to melanoma through a variety of mechanisms: i) by promoting invasion and migration through activation of MMP2 and RAC1[12]; ii) by inhibiting the tumor suppressor protein SPRY4[13]; and by promoting melanoma cell growth through the cleavage and activation of Notch1[14]. Given the multiplicity of functions that MT1-MMP modulates in melanoma and the fact that it is located on the plasma-membrane, it may be an ideal target for therapeutic intervention.…”