Nuclear Matrix Metalloproteinase Research Articles

Unravelling the Network of Nuclear Matrix Metalloproteinases for Targeted Drug Design

Simple SummaryNuclear matrix metalloproteinases are emerging to have distinct functions in a number of pathological conditions and physiological processes. In this article, we review what progress has been made in this area of research and discuss their potential in being targeted for future therapeutic design.Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that are responsible for the degradation of a wide range of extracellular matrix proteins, which are involved in many cellular processes to ensure the normal development of tissues and organs. Overexpression of MMPs has been observed to facilitate cellular growth, migration, and metastasis of tumor cells during cancer progression. A growing number of these proteins are being found to exist in the nuclei of both healthy and tumor cells, thus highlighting their localization as having a genuine purpose in cellular homeostasis. The mechanism underlying nuclear transport and the effects of MMP nuclear translocation have not yet been fully elucidated. To date, nuclear MMPs appear to have a unique impact on cellular apoptosis and gene regulation, which can have effects on immune response and tumor progression, and thus present themselves as potential therapeutic targets in certain types of cancer or disease. Herein, we highlight and evaluate what progress has been made in this area of research, which clearly has some value as a specific and unique way of targeting the activity of nuclear matrix metalloproteinases within various cell types.

760 Melanin may mediate visible light induced phototoxicity in darker skin types

Visible light (VL), a major component of solar radiation, differentially induces pigmentation in skin of color, an effect likely related to inherent melanization. A chromophore, melanin absorbs light within the VL wavelength. We hypothesize that clinical and histologic responses to VL are determined by epidermal melanin content and distribution. Nuclear matrix metalloproteinase (MMP-1), a proapoptotic mediator of photodamage may play a central role in skin type specific responses to VL. Enrolled participants were grouped by skin type (light=6,dark=6). Photoprotected sites were exposed daily x4days to 480J/cm2 of VL at 200mW(FiberLite High Intensity Illuminator Series 180,Dolan Jenner Industries) for a total dose of 1920J/cm2as tolerated. Treated and control sites were biopsied 24h after the last exposure and stained with Masson’s Trichrome and Fontana-Masson (FM) to assess collagen and melanin deposition, respectively. MMP-1 deposition was detected by indirect immunofluorescence (IF). Dark skin types did not tolerate the full VL regimen with blistering occurring in all subjects at doses of 220-880J/cm2. We found epidermal MMP-1 expression and nuclear localization in keratinocytes in dark but not in light skin. Nuclear localization correlated with areas of highest melanin density per FM stain. While there was no significant difference in MMP expression of treated light skin from control, collagen stains showed decreased stain intensity and thickened, wavy collagen bundles in both light (mean fold change[FC]=1.46,SEM+0.11), and dark skin (FC=1.19,+0.05). Herein, we demonstrate the acute effects of high power VL exposure in light and dark skin. VL can cause degenerative changes in collagen similar to acute UV irradiation or thermal injury, occurring independent of skin melanization. While the role of melanin in photoprotection is well defined, given the pro-apoptotic function of nuclear MMPs, our findings suggest a potential mechanism by which melanin may mediate VL induced phototoxicity. These observations show a “light” and “dark” side to melanin that warrants further investigation.

Nuclear matrix metalloproteinase-2 in the cardiomyocyte and the ischemic-reperfused heart

Matrix metalloproteinases (MMPs) are zinc-dependent proteases involved in intra- and extra-cellular matrix remodeling resulting from oxidative stress injury to the heart. MMP-2 was the first MMP to be localized to the nucleus; however, its biological functions there are unclear. We hypothesized that MMP-2 is present in the nucleus under normal physiological conditions but increases during myocardial ischemia-reperfusion (I/R) injury-induced oxidative stress, proteolyzing nuclear structural proteins. Lamins are intermediate filament proteins that provide structural support to the nucleus and are putative targets of MMP-2. To identify lamin susceptibility to MMP-2 proteolysis, purified lamin A or B was incubated with MMP-2 in vitro. Lamin A, but not lamin B, was proteolysed by MMP-2 into an approximately 50kDa fragment, which was also predicted by in silico cleavage site analysis. Immunofluorescent confocal microscopy and subcellular fractionation showed MMP-2 both in the cytosol and nuclei of neonatal rat ventricular myocytes. Rat hearts were isolated and perfused by the Langendorff method aerobically, or subjected to I/R injury in the presence or absence of o-phenanthroline, an MMP inhibitor. Nuclear fractions extracted from I/R hearts showed increased MMP-2 activity, but not protein level. The level of troponin I, a known sarcomeric target of MMP-2, was rescued in I/R hearts treated with o-phenanthroline, demonstrating the efficacy of MMP inhibition. However, lamin A or B levels remained unchanged in I/R hearts. MMP-2 has a widespread subcellular distribution in cardiomyocytes, including a significant presence in the nucleus. The increase in nuclear MMP-2 activity seen during stunning injury here, indicates yet unknown biological actions, other than lamin proteolysis, which may require more severe ischemia to effect.

Comparative Analysis of NLS Sequence Suggests the Evolutionary Origin of Nuclear Matrix Metalloproteinase 7 during Cancer Evolution

Comparative Analysis of NLS Sequence Suggests the Evolutionary Origin of Nuclear Matrix Metalloproteinase 7 during Cancer Evolution

Abstract 420: Critical role of MMP-2 and GATA-1 nuclear interaction in the regulation of ionizing radiation (IR)-induced IL-10/Stat3-mediated invasion and migration in glioblastoma.

Abstract Glioblastoma multiforme (GBM) is the most lethal human brain tumor with high recurrence rates despite the existence of multimodal treatments including chemotherapy and radiation after surgical tumor resection. Augmented tumor metastasis after irradiation (IR) has been attributed to enhanced extracellular protease levels in tumors. Secreted or cleaved matrix metalloproteinase-2 (MMP-2) levels were reported to be elevated in irradiated tumors. Interestingly, previous in silico prediction analyses identified the presence of a putative nuclear localization signal (NLS) in MMP-2 and reported the cleavage of PARP by nuclear-MMP-2. However, MMP-2 nuclear localization in possible correlation with tumor progression has not been identified to date. In addition to membrane and cytoplasmic expression of MMP-2, we observed prominent MMP-2 nuclear localization, which is further elevated in IR (8 Gy)-treated human glioma xenograft cells 4910 and 5310. Interestingly, The protein-transcription factor (TF) interaction arrays using 4910 nuclear extracts revealed the potential binding of nuclear-MMP-2 with several transcription factors including CEF-2, c-Rel, FOXO4, GAS, GATA-1, MUSF-1, p300, PARP and RREB1. Co-IP experiments showed the direct binding between MMP-2/GATA-1 in glioma. Further, we also observed the presence of MMP-2 in the GATA-1 DNA-binding complex and its recruitment onto the promoter of IL-10, a GATA-1 target gene. ChIP-cloning with anti-MMP-2 antibody confirmed the specific binding of MMP-2 with GATA-1 consensus elements. We also observed that the MMP-2/GATA-1 nuclear co-localization was elevated in correlation with increasing GBM pathological grades. Downregulation of MMP-2 inhibited the GATA-1 expression and DNA-binding activity and abrogated IR-induced migration and invasion in these cells. Conversely, treatment with recombinant MMP-2 protein elevated the GATA-1 DNA-binding activity and increased IL-10 and phospho-Stat3 expression in correlation with increased invasion and migration. In vivo orthotopic experiments with MMP-2.siRNA decreased tumor growth in nude mice and inhibited nuclear MMP-2 and GATA-1 expression levels in tumors. To our knowledge, this is the first study demonstrating significant IR-induced nuclear translocation of MMP-2 and shows the functional association between MMP-2/GATA-1 in the regulation of IL-10/Stat3-mediated migration and invasion. Our results suggest the potential therapeutic efficacy of targeting MMP-2/GATA-1 liaison in glioma treatment. Citation Format: Divya Kesanakurti, Dilip Maddirela, Meena Gujrati, Jasti S. Rao. Critical role of MMP-2 and GATA-1 nuclear interaction in the regulation of ionizing radiation (IR)-induced IL-10/Stat3-mediated invasion and migration in glioblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 420. doi:10.1158/1538-7445.AM2013-420