Tissue inhibitor of metalloproteinase 1 (TIMP-1) promotes plasmablastic differentiation of a Burkitt lymphoma cell line: implications in the pathogenesis of plasmacytic/plasmablastic tumors

Desmoglein-Specific B-Cell-Targeted Single-Cell Analysis Revealing Unique Gene Regulation in Patients with Pemphigus

Autoreactive B cells are assumed to play a critical role in pemphigus; however, the characteristics of these cells are not yet fully understood. In this study, 23 pemphigus vulgaris or pemphigus foliaceus samples were used to isolate circulating desmoglein (DSG)-specific B cells. Transcriptome analysis of the samples was performed at the single-cell level to detect genes involved in disease activity. DSG1- or DSG3-specific B cells from three patients' differentially expressed genes related to T cell costimulation (CD137L) as well as B-cell differentiation (CD9, BATF, TIMP1) and inflammation (S100A8, S100A9, CCR3), compared with nonspecific B cells from the same patients. When the DSG1-specific B cells before and after treatment transcriptomes of the patient with pemphigus foliaceus were compared, there were changes in several B-cell activation pathways not detected in non-DSG1-specific B cells. This study clarifies the transcriptomic profile of autoreactive B cells in patients with pemphigus and documents the gene expression related to disease activity. Our approach can be applied to other autoimmune diseases and has the potential for future detection of disease-specific autoimmune cells.

Myeloma Microenvironmental TIMP1 Induces the Invasive Phenotype in Fibroblasts to Modulate Disease Progression

Tissue inhibitors of metalloproteinases (TIMPs) are endogenous matrix metalloproteinase inhibitors. TIMP1 is produced by cancer cells and has pleiotropic activities. However, its role and source in multiple myeloma (MM) are unclear. Here, we evaluated TIMP1 protein and mRNA levels in bone marrow (BM) plasma cells and assessed the effects of TIMP1 expression on fibroblast invasive capacity using three-dimensional spheroid cell invasion assays. TIMP1 mRNA and protein levels were elevated when patients progressed from monoclonal gammopathy of undetermined significance or smouldering myeloma to MM. Furthermore, TIMP1 levels decreased at complete response and TIMP1 protein levels increased with higher international staging. TIMP1 mRNA levels were markedly higher in extramedullary plasmacytoma and MM with t(4;14). Overall survival and post-progression survival were significantly lower in MM patients with high TIMP1 protein. Recombinant TIMP1 did not directly affect MM cells but enhanced the invasive capacity of fibroblasts; this effect was suppressed by treatment with anti-TIMP1 antibodies. Fibroblasts supported myeloma cell invasion and expansion in extracellular matrix. Overall, these results suggested that MM-derived TIMP1 induces the invasive phenotype in fibroblasts and is involved in disease progression. Further studies are required to elucidate the specific roles of TIMP1 in MM and facilitate the development of novel therapies targeting the TIMP1 pathway.

TIMP-1 Dependent Modulation of Metabolic Profiles Impacts Chemoresistance in NSCLC

The development of chemoresistance remains a significant barrier to treating NSCLC. Alteration of cancer cell metabolism is an important mechanism for chemoresistance. This study explored the role of aberrant metabolism in TIMP-1-mediated chemoresistance. Bioinformatics analysis identified an association of high TIMP-1 with altered energy metabolism. We have defined the role of depolarized mitochondria through a reduction in lactate secretion, higher ROS levels in TIMP-1 KD cells and reduced GSH levels. TIMP-1 modulates the metabolic profile via acetylation of mitochondrial STAT3 and its interaction with CD44. Intriguingly, monomers of acetylated STAT3 were critical for altered metabolism, whereas STAT3 dimers abrogated this function. Further, the mitochondrial metabolic profile was also altered in a cisplatin-resistant clone of A549 cells. We also correlated the immunoexpression of CD44, STAT3 and TIMP-1 in patient samples. This study provided evidence that TIMP-1 alters the metabolic profile by modulating mitochondrial metabolism via the CD44-STAT3 axis through its effects on STAT3 acetylation. It also lent further support to the critical role of TIMP-1 in chemoresistance. Interrogation of the TCGA-LUAD dataset revealed perturbations in the critical modulator that can alter metabolic states in cancer cells. Higher expression of a five-gene signature, including TIMP-1, correlated with immunosuppressive cells and was found to be associated with overall survival. This study identified several metabolic mechanisms that could influence therapeutic options and prognosis in NSCLC patients.

Cut loose TIMP-1: an emerging cytokine in inflammation

Appreciation of the entire biological impact of an individual protein can be hampered by its original naming based on one function only. Tissue inhibitor of metalloproteinases-1 (TIMP-1), mostly known for its eponymous function to inhibit metalloproteinases, exhibits only a fraction of its cellular effects via this feature. Recently, TIMP-1 emerged as a potent cytokine acting via various cell-surface receptors, explaining a so-far under-appreciated role of TIMP-1-mediated signaling on immune cells. This, at least partly, resolved why elevated blood levels of TIMP-1 correlate with progression of numerous inflammatory diseases. Here, we emphasize the necessity of unbiased name-independent recognition of structure-function relationships to properly appreciate the biological potential of TIMP-1 and other cytokines in complex physiological processes such as inflammation.

Soluble markers of B cell activation suggest a role of B cells in the pathogenesis of systemic sclerosis-associated pulmonary arterial hypertension

Introduction

Soluble markers of B cell activation are interesting diagnostic and prognostic tools in autoimmune diseases. Data in systemic sclerosis (SSc) are scarce and few studies focused on their association with disease characteristics.

Methods

1. Serum levels of 14 B cell biomarkers (β2-microglobulin, rheumatoid factor (RF), immunoglobulins (Ig) G, IgA, IgM, BAFF, APRIL, soluble (s)TACI, sBCMA sCD21, sCD23, sCD25, sCD27, CXCL13) were measured in SSc patients and healthy controls (HC). 2. Associations between these biomarkers and SSc characteristics were assessed. 3. The pathophysiological relevance of identified associations was explored by studying protein production in B cell culture supernatant.

Results

In a discovery panel of 80 SSc patients encompassing the broad spectrum of disease manifestations, we observed a higher frequency of RF positivity, and increased levels of β2-microglobulin, IgG and CXCL13 compared with HC. We found significant associations between several biomarkers and SSc characteristics related to disease phenotype, activity and severity. Especially, serum IgG levels were associated with pulmonary hypertension (PH); β2-microglobulin with Nt-pro-BNP and DLCO; and BAFF with peak tricuspid regurgitation velocity (TRV). In a validation cohort of limited cutaneous SSc patients without extensive ILD, we observed lower serum IgG levels, and higher β2-microglobulin, sBCMA, sCD23 and sCD27 levels in patients with pulmonary arterial hypertension (PAH). BAFF levels strongly correlated with Nt-pro-BNP levels, FVC/DLCO ratio and peak TRV in SSc-PAH patients. Cultured SSc B cells showed increased production of various angiogenic factors (angiogenin, angiopoietin-1, VEGFR-1, PDGF-AA, MMP-8, TIMP-1, L-selectin) and decreased production of angiopoietin-2 compared to HC.

Conclusion

Soluble markers of B cell activation could be relevant tools to assess organ involvements, activity and severity in SSc. Their associations with PAH could plead for a role of B cell activation in the pathogenesis of pulmonary microangiopathy. B cells may contribute to SSc vasculopathy through production of angiogenic mediators.

Abnormal B-cell development in TIMP-deficient bone marrow

Bone marrow (BM) is the primary site of hematopoiesis and is responsible for a lifelong supply of all blood cell lineages. The process of hematopoiesis follows key intrinsic programs that also integrate instructive signals from the BM niche. First identified as an erythropoietin-potentiating factor, the tissue inhibitor of metalloproteinase (TIMP) protein family has expanded to 4 members and has widely come to be viewed as a classical regulator of tissue homeostasis. By virtue of metalloprotease inhibition, TIMPs not only regulate extracellular matrix turnover but also control growth factor bioavailability. The 4 mammalian TIMPs possess overlapping enzyme-inhibition profiles and have never been studied for their cumulative role in hematopoiesis. Here, we show that TIMPs are critical for postnatal B lymphopoiesis in the BM. TIMP-deficient mice have defective B-cell development arising at the pro-B-cell stage. Expression analysis of TIMPless hematopoietic cell subsets pointed to an altered B-cell program in the Lineage-Sca-1+c-Kit+ (LSK) cell fraction. Serial and competitive BM transplants identified a defect in TIMP-deficient hematopoietic stem and progenitor cells for B lymphopoiesis. In parallel, reverse BM transplants uncovered the extrinsic role of stromal TIMPs in pro- and pre-B-cell development. TIMP deficiency disrupted CXCL12 localization to LepR+ cells, and increased soluble CXCL12 within the BM niche. It also compromised the number and morphology of LepR+ cells. These data provide new evidence that TIMPs control the cellular and biochemical makeup of the BM niche and influence the LSK transcriptional program required for optimal B lymphopoiesis.

Identification of invariant chain CD74 as a functional receptor of tissue inhibitor of metalloproteinases-1 (TIMP-1)

Multifunctionality of tissue inhibitor of metalloproteinases-1 (TIMP-1) comprising antiproteolytic as well as cytokinic activity has been attributed to its N-terminal and C-terminal domains, respectively. The molecular basis of the emerging proinflammatory cytokinic activity of TIMP-1 is still not completely understood. The cytokine receptor invariant chain (CD74) is involved in many inflammation-associated diseases and is highly expressed by immune cells. CD74 triggers zeta chain–associated protein kinase-70 (ZAP-70) signaling–associated activation upon interaction with its only known ligand, the macrophage migration inhibitory factor. Here, we demonstrate TIMP-1–CD74 interaction by coimmunoprecipitation and confocal microscopy in cells engineered to overexpress CD74. In silico docking in HADDOCK predicted regions of the N-terminal domain of TIMP-1 (N-TIMP-1) to interact with CD74. This was experimentally confirmed by confocal microscopy demonstrating that recombinant N-TIMP-1 lacking the entire C-terminal domain was sufficient to bind CD74. Interaction of TIMP-1 with endogenously expressed CD74 was demonstrated in the Namalwa B lymphoma cell line by dot blot binding assays as well as confocal microscopy. Functionally, we demonstrated that TIMP-1–CD74 interaction triggered intracellular ZAP-70 activation. N-TIMP-1 was sufficient to induce ZAP-70 activation and interference with the cytokine-binding site of CD74 using a synthetic peptide–abrogated TIMP-1-mediated ZAP-70 activation. Altogether, we here identified CD74 as a receptor and mediator of cytokinic TIMP-1 activity and revealed TIMP-1 as moonlighting protein harboring both cytokinic and antiproteolytic activity within its N-terminal domain. Recognition of this functional TIMP-1–CD74 interaction may shed new light on clinical attempts to therapeutically target ligand-induced CD74 activity in cancer and other inflammatory diseases.

Adeno-Associated Virus-Mediated Gene Transfer of Tissue Inhibitor of Metalloproteinases-1 Impairs Neutrophil Extracellular Trap Formation and Ameliorates Hepatic Ischemia and Reperfusion Injury

Matrix metalloproteinase-9 (MMP-9) is abundantly expressed by infiltrating leukocytes and contributes to the pathogenesis of hepatic ischemia and reperfusion injury (IRI). On the other hand, its physiological inhibitor, the tissue inhibitor of metalloproteinases-1 (TIMP-1), is available in insufficient levels to hamper MMP-9 activity during hepatic IRI. In this study, we generated recombinant adeno-associated virus type 8 vectors (rAAV8) encoding mouse TIMP-1 driven by a liver-specific thyroxine-binding globulin promoter as a strategy to increase the levels of TIMP-1 during liver IRI. Biodistribution analysis confirmed selective overexpression of TIMP-1 in livers of rAAV8-TIMP-1 vector treated C57BL/6 mice. rAAV8-TIMP-1-treated mice showed reduced MMP-9 activity, diminished leukocyte trafficking and activation, lowered transaminase levels, and improved histology after liver IRI. Moreover, the rAAV8-TIMP-1 vector therapy enhanced significantly the 7-day survival rate of TIMP-1^-/- mice subjected to hepatic IRI. Neutrophils are the first cells recruited to inflamed tissues and, once activated, they release nuclear DNA-forming web-like structures, known as neutrophil extracellular traps. It was found that TIMP-1 has the ability to reduce formation of neutrophil extracellular traps and, consequently, limit the impact of neutrophil extracellular trap-mediated cytotoxicity in hepatic IRI. This is the first report demonstrating that TIMP-1 overexpression is hepatoprotective in ischemia and reperfusion injury. Hence, TIMP-1 may represent a promising molecule for drug development to treat liver IRI.

The tissue inhibitor of metalloproteinases-1 (TIMP-1) promotes survival and migration of acute myeloid leukemia cells through CD63/PI3K/Akt/p21 signaling

We and others have shown that the Tissue Inhibitor of Metalloproteinases-1 (TIMP-1), a member of the inflammatory network exerting pleiotropic effects in the bone marrow (BM) microenvironment, regulates the survival and proliferation of different cell types, including normal hematopoietic progenitor cells. Moreover, TIMP-1 has been shown to be involved in cancer progression. However, its role in leukemic microenvironment has not been addressed. Here, we investigated the activity of TIMP-1 on Acute Myelogenous Leukemia (AML) cell functions. First, we found that TIMP-1 levels were increased in the BM plasma of AML patients at diagnosis. In vitro, recombinant human (rh)TIMP-1 promoted the survival and cell cycle S-phase entry of AML cells. These kinetic effects were related to the downregulation of cyclin-dependent kinase inhibitor p21. rhTIMP-1 increases CXCL12-driven migration of leukemic cells through PI3K signaling. Interestingly, activation of CD63 receptor was required for TIMP-1's cytokine/chemokine activity. Of note, rhTIMP-1 stimulation modulated mRNA expression of Hypoxia Inducible Factor (HIF)-1α, downstream of PI3K/Akt activation. We then co-cultured AML cells with normal or leukemic mesenchymal stromal cells (MSCs) to investigate the interaction of TIMP-1 with cellular component(s) of BM microenvironment. Our results showed that the proliferation and migration of leukemic cells were greatly enhanced by rhTIMP-1 in presence of AML-MSCs as compared to normal MSCs. Thus, we demonstrated that TIMP-1 modulates leukemic blasts survival, migration and function via CD63/PI3K/Akt/p21 signaling. As a “bad actor” in a “bad soil”, we propose TIMP-1 as a potential novel therapeutic target in leukemic BM microenvironment.

TIMPs: versatile extracellular regulators in cancer

A compelling long-term goal of cancer biology is to understand the crucial players during tumorigenesis in order to develop new interventions. Here, we review how the four non-redundant tissue inhibitors of metalloproteinases (TIMPs) regulate the pericellular proteolysis of a vast range of matrix and cell surface proteins, generating simultaneous effects on tumour architecture and cell signalling. Experimental studies demonstrate the contribution of TIMPs to the majority of cancer hallmarks, and human cancers invariably show TIMP deregulation in the tumour or stroma. Of the four TIMPs, TIMP1 overexpression or TIMP3 silencing is consistently associated with cancer progression or poor patient prognosis. Future efforts will align mouse model systems with changes in TIMPs in patients, will delineate protease-independent TIMP function, will pinpoint therapeutic targets within the TIMP-metalloproteinase-substrate network and will use TIMPs in liquid biopsy samples as biomarkers for cancer prognosis.

Elevated circulating tissue inhibitor of metalloproteinase 1 (TIMP-1) levels are associated with neuroendocrine differentiation in castration resistant prostate cancer

BACKGROUND

Tissue inhibitor of metalloproteinase-1 (TIMP-1) is a 28.5 kDa secreted glycoprotein that inhibits matrix metalloproteinase (MMP) activity. Our group has previously shown that elevated plasma TIMP-1 levels predict poor survival in metastatic castration-resistant prostate cancer (CRPC) patients; however, the underlying source and impact of elevated circulating TIMP-1 protein is unknown.

METHODS

In this study, we used qRT-PCR, ELISA and immunohistochemistry to evaluate TIMP-1 expression in androgen-sensitive and resistant prostate cancer (PC) cell lines, tumor tissues and patient sera, and to correlate TIMP-1 levels to expression of chromogranin A (CGA), an established marker of neuroendocrine differentiation (NED). We also explored the relationship between TIMP-1 overexpression and induction of NED by overexpressing TIMP-1 in androgen-sensitive LNCaP cells, as well as by inducing NED of LNCaP cells with IL-6.

RESULTS

Patients with CRPC have significantly higher serum TIMP-1 levels compared to patients with hormone-sensitive disease. Although circulating TIMP-1 levels were increased, peripheral blood cells were not the source of elevation. Instead, elevated TIMP-1 expression was associated with higher expression of CGA in both blood and metastatic tumor tissue. We further show that androgen receptor (AR) and PSA non-expressing prostate cancer cell lines known to display NED phenotypes such as PC-3, PC-3M, and DU145 cells, expressed high levels of TIMP-1, in contrast to AR (+) and PSA (+) adenocarcinoma cell lines such as LNCaP, VCaP, and LAPC-4, which had barely detectable levels of TIMP-1. In addition, ectopic overexpression of TIMP-1 in LNCaP cells did not induce NED. However, TIMP-1 mRNA expression was elevated >10-fold during IL-6-induced NED of LNCaP cells, suggesting that TIMP-1 overexpression accompanies, but is not the driving force for NED. Finally, we show that conditioned media from androgen-resistant PC-3, PC-3M, and DU145 cells induced TIMP-1 mRNA expression in primary prostate stromal fibroblasts in an ERK and NF-κB dependent manner.

CONCLUSIONS

We provide in vitro and clinical evidence to support the association between NED and elevated circulating TIMP-1 expression in CRPC. Our observation supports further evaluation of TIMP-1 as a tissue and serum biomarker for NED in CRPC.

The effects of the fungicides fenhexamid and myclobutanil on SH-SY5Y and U-251 MG human cell lines

Mixtures of pesticides in foodstuffs and the environment are ubiquitous in the developed world and although agents are usually exhaustively tested individually, the toxicological implications of pesticide mixtures are underreported. In this study, the effects of two fungicides, fenhexamid and myclobutanil were investigated individually and in combination on two human cell lines, SH-SY5Y neuronal cells and U-251 MG glial cells. After 48h of incubation with increasing concentrations of pesticides ranging from 1 to 1000μM, gene expression profiles were studied in addition to toxicity end points, including cell viability, mitochondrial depolarisation as well as cellular glutathione maintenance. There were no significant differences between the susceptibility of the two cell lines in terms of cell viability assessment or mitochondrial membrane potential, when agents were administered either individually or in combination. By contrast, in the presence of the fungicides, the SH-SY5Y cells showed significantly greater susceptibility to oxidative stress in terms of total thiol depletion in comparison with the astrocytic cells. Treatment with the two pesticides led to significant changes in the cell lines' expression of several genes which regulate cell cycle control and growth (RB1, TIMP1) as well as responses to DNA attrition (ATM and CDA25A) and control of apoptosis (FAS). There was no evidence in this study that the combination of fenhexamid and myclobutanil was significantly more toxic than individual exposure, although gene expression changes suggested there may be differences in the sub-lethal response of both cell lines to both individual and combined exposure.

Roles of matrix metalloproteinases and their natural inhibitors in prostate cancer progression

Matrix metalloproteinases (MMPs), a group of zinc-dependent endopeptidases involved in the degradation of the extracellular matrix, play an important role in tissue remodeling associated with various physiological processes such as morphogenesis, angiogenesis, and tissue repair, as well as pathological processes including cirrhosis, arthritis and cancer. The MMPs are well established as mediators of tumor invasion and metastasis by breaking down connective tissue barriers. Although there has been a vast amount of literature on the role of MMPs in invasion, metastasis and angiogenesis of various cancers, the role of these endopeptidases in prostate cancer progression has not been systematically reviewed. This overview summarizes findings on the tissue and blood expression of MMPs, their function, regulation and prognostic implication in human prostate cancer, with a focus on MMP-2, -7, -9, MT1-MMP and tissue inhibitor of metalloproteinase 1 (TIMP-1). This review also summarizes the efficacy and failure of early-generation matrix metalloproteinase inhibitors (MMPIs) in the treatment of metastatic prostate cancer and highlights the lessons and challenges for next generation MMPIs.

Biological Effects of Clinically Relevant CoCr Nanoparticles in the Dura Mater: An Organ Culture Study

Medical interventions for the treatment of spinal disc degeneration include total disc replacement and fusion devices. There are, however, concerns regarding the generation of wear particles by these devices, the majority of which are in the nanometre sized range with the potential to cause adverse biological effects in the surrounding tissues. The aims of this study were to develop an organ culture model of the porcine dura mater and to investigate the biological effects of CoCr nanoparticles in this model. A range of histological techniques were used to analyse the structure of the tissue in the organ culture. The biological effects of the CoCr wear particles and the subsequent structural changes were assessed using tissue viability assays, cytokine assays, histology, immunohistochemistry, and TEM imaging. The physiological structure of the dura mater remained unchanged during the seven days of in vitro culture. There was no significant loss of cell viability. After exposure of the organ culture to CoCr nanoparticles, there was significant loosening of the epithelial layer, as well as the underlying collagen matrix. TEM imaging confirmed these structural alterations. These structural alterations were attributed to the production of MMP-1, -3, -9, -13, and TIMP-1. ELISA analysis revealed that there was significant release of cytokines including IL-8, IL-6, TNF-α, ECP and also the matrix protein, tenascin-C. This study suggested that CoCr nanoparticles did not cause cytotoxicity in the dura mater but they caused significant alterations to its structural integrity that could lead to significant secondary effects due to nanoparticle penetration, such as inflammation to the local neural tissue.

Cytokine functions of TIMP-1

The tissue inhibitors of metalloproteinases (TIMPs) are well recognized for their role in extracellular matrix remodeling by controlling the activity of matrix metalloproteinases (MMPs). Independent of MMP inhibition, TIMPs act as signaling molecules with cytokine-like activities thereby influencing various biological processes including cell growth, apoptosis, differentiation, angiogenesis, and oncogenesis. Recent studies on TIMP-1's cytokine functions have identified complex regulatory networks involving a specific surface receptor and subsequent signaling pathways including miRNA-mediated posttranscriptional regulation of gene expression that ultimately control the fate and behavior of the cells. The present review summarizes the current knowledge on TIMP-1 as a cytokine modulator of cell functions, outlines recent progress in defining molecular pathways that transmit TIMP-1 signals from the cell periphery into the nucleus, and discusses TIMP-1's role as a cytokine in the pathophysiology of cancer and other human diseases.

Molecular events underlying interleukin-6 independence in a subclone of the CMA-03 multiple myeloma cell line

We explored the molecular mechanisms involved in the establishement of CMA-03/06, an IL-6-independent variant of the multiple myeloma cell line CMA-03 previously generated in our Institution. CMA-03/06 cells grow in the absence of IL-6 with a doubling time comparable with that of CMA-03 cells; neither the addition of IL6 (IL-6) to the culture medium nor co-culture with multipotent mesenchymal stromal cells increases the proliferation rate, although they maintain the responsiveness to IL-6 stimulation as demonstrated by STAT1, STAT3, and STAT5 induction. IL-6 independence of CMA-03/06 cells is not apparently due to the development of an autocrine IL-6 loop, nor to the observed moderate constitutive activation of STAT5 and STAT3, since STAT3 silencing does not affect cell viability or proliferation. When compared to the parental cell line, CMA-03/06 cells showed an activated pattern of the NF-κB pathway. This finding is supported by gene expression profiling (GEP) analysis identifying an appreciable fraction of modulated genes (28/308) in the CMA-03/06 subclone reported to be involved in this pathway. Furthermore, although more resistant to apoptotic stimuli compared to the parental cell line, CMA-03/06 cells display a higher sensibility to NF-κB inhibition induced by bortezomib. Finally, GEP analysis suggests an involvement of a number of cytokines, which might contribute to IL-6 independence of CMA-03/06 by stimulating growth and antiapoptotic processes. In conclusion, the parental cell-line CMA-03 and its variant CMA-03/06 represent a suitable model to further investigate molecular mechanisms involved in the IL-6-independent growth of myeloma cells.

Tissue inhibitor of metalloproteinase-1 (TIMP-1) regulates mesenchymal stem cells through let-7f microRNA and Wnt/β-catenin signaling

Tissue inhibitor of metalloproteinases 1 (TIMP-1) is a matrix metalloproteinase (MMP)-independent regulator of growth and apoptosis in various cell types. The receptors and signaling pathways that are involved in the growth factor activities of TIMP-1, however, remain controversial. RNA interference of TIMP-1 has revealed that endogenous TIMP-1 suppresses the proliferation, metabolic activity, and osteogenic differentiation capacity of human mesenchymal stem cells (hMSCs). The knockdown of TIMP-1 in hMSCs activated the Wnt/β-catenin signaling pathway as indicated by the increased stability and nuclear localization of β-catenin in TIMP-1-deficient hMSCs. Moreover, TIMP-1 knockdown cells exhibited enhanced β-catenin transcriptional activity, determined by Wnt/β-catenin target gene expression analysis and a luciferase-based β-catenin-activated reporter assay. An analysis of a mutant form of TIMP-1 that cannot inhibit MMP indicated that the effect of TIMP-1 on β-catenin signaling is MMP independent. Furthermore, the binding of CD63 to TIMP-1 on the surface of hMSCs is essential for the TIMP-1-mediated effects on Wnt/β-catenin signaling. An array analysis of microRNAs (miRNAs) and transfection studies with specific miRNA inhibitors and mimics showed that let-7f miRNA is crucial for the regulation of β-catenin activity and osteogenic differentiation by TIMP-1. Let-7f was up-regulated in TIMP-1-depleted hMSCs and demonstrably reduced axin 2, an antagonist of β-catenin stability. Our results demonstrate that TIMP-1 is a direct regulator of hMSC functions and reveal a regulatory network in which let-7f modulates Wnt/β-catenin activity.

Bone marrow microenvironment in myelomagenesis: its potential role in early diagnosis

Multiple myeloma (MM) is the second most common hematological malignancy, with an overall survival of 4-6 years. It is always preceded by a premalignant stage called monoclonal gammopathy of unknown significance (MGUS). Importantly, at this time we lack reliable predictors to determine who will progress from MGUS to MM, and who will remain stable. The bone marrow microenvironment plays a key role in myelomagenesis (growth, survival and migration of malignant plasma cells). In the present review, we summarize and discuss our current understanding of the bone marrow microenvironment and its compartments in relation to myelomagenesis. Although it remains to be proven, we believe that an improved characterization of the cellular constituents, the extracellular matrix components and the soluble factors of the bone marrow could open up novel avenues to better understand underlying mechanisms of the transformation from MGUS to MM. Ultimately, this will lead to the development of early treatment of high-risk precursor disease aimed to delay/prevent MM.

Role of tissue inhibitor of metalloproteinases-1 in the development of autoimmune lymphoproliferation

BACKGROUND

Inherited defects decreasing function of the Fas death receptor cause autoimmune lymphoproliferative syndrome and its variant Dianzani's autoimmune lymphoproliferative disease. Analysis of the lymphocyte transcriptome from a patient with this latter condition detected striking over-expression of osteopontin and tissue inhibitor of metalloproteinases-1. Since previous work on osteopontin had detected increased serum levels in these patients, associated with variations of its gene, the aim of this work was to extend the analysis to tissue inhibitor of metalloproteinases-1.

DESIGN AND METHODS

Tissue inhibitor of metalloproteinases-1 levels were evaluated in sera and culture supernatants from patients and controls by enzyme-linked immunosorbent assay. Activation- and Fas-induced cell death were induced, in vitro, using anti-CD3 and anti-Fas antibodies, respectively.

RESULTS

Tissue inhibitor of metalloproteinases-1 levels were higher in sera from 32 patients (11 with autoimmune lymphoproliferative syndrome and 21 with Dianzani's autoimmune lymphoproliferative disease) than in 50 healthy controls (P<0.0001), unassociated with variations of the tissue inhibitor of metalloproteinases-1 gene. Both groups of patients also had increased serum levels of osteopontin. In vitro experiments showed that osteopontin increased tissue inhibitor of metalloproteinases-1 secretion by peripheral blood monocytes. Moreover, tissue inhibitor of metalloproteinases-1 significantly inhibited both Fas- and activation-induced cell death of lymphocytes.

CONCLUSIONS

These data suggest that high osteopontin levels may support high tissue inhibitor of metalloproteinases-1 levels in autoimmune lymphoproliferative syndrome and Dianzani's autoimmune lymphoproliferative disease, and hence worsen the apoptotic defect in these diseases.

Adhesion molecules--The lifelines of multiple myeloma cells

Multiple myeloma is an incurable hematological malignancy of terminally differentiated immunoglobulin-producing plasma cells. As a common presentation of the disease, the malignant plasma cells accumulate and proliferate in the bone marrow, where they disrupt normal hematopoiesis and bone physiology. Multiple myeloma cells and the bone marrow microenvironment are linked by a composite network of interactions mediated by soluble factors and adhesion molecules. Integrins and syndecan-1/CD138 are the principal multiple myeloma receptor systems of extracellular matrix components, as well as of surface molecules of stromal cells. CD44 and RHAMM are the major hyaluronan receptors of multiple myeloma cells. The SDF-1/CXCR4 axis is a key factor in the homing of multiple myeloma cells to the bone marrow. The levels of expression and activity of these adhesion molecules are controlled by cytoplasmic operating mechanisms, as well as by extracellular factors including enzymes, growth factors and microenvironmental conditions. Several signaling responses are activated by adhesive interactions of multiple myeloma cells, and their outcomes affect the survival, proliferation and migration of these cells, and in many cases generate a drug-resistant phenotype. Hence, the adhesion systems of multiple myeloma cells are attractive potential therapeutic targets. Several approaches are being developed to disrupt the activities of adhesion molecules in multiple myeloma cells, including small antagonist molecules, direct targeting by immunoconjugates, stimulation of immune responses against these molecules, and signal transduction inhibitors. These potential novel therapeutics may be incorporated into current treatment schemes, or directed against minimal residual malignant cells during remission.

Functional genomics of endothelial cells treated with anti-angiogenic or angiopreventive drugs

Angiogenesis is a highly regulated physiological process that has been studied in considerable detail given its importance in several chronic pathologies. Many endogenous factors and hormones intervene in the regulation of angiogensis and classical as well as targeted drugs have been developed for its control. Angiogenesis inhibition has come off the bench and entered into clinical application for cancer therapy, particularly for metastatic disease. While the clinical benefit is currently in terms of months, preclinical data suggest that novel drugs and drug combinations could lead to substantial improvement. The many targets of endogenous angiogenesis inhibitors reflect the complexity of the process; in contrast, current clinical therapies mainly target the vascular endothelial growth factor system. Cancer chemopreventive compounds can retard tumor insurgence and delay or prevent metastasis and many of these molecules hinder angiogenesis, a mechanism that we termed angioprevention. Angiopreventive drugs appear to prevalently act through the inhibition of the pro-inflammatory and anti-apoptotic player NFkappaB, thus contrasting inflammation dependent angiogenesis. Relatively little is known concerning the effects of these angiogenesis inhibitors on gene expression of endothelial cells, the main target of many of these molecules. Here we provide an exhaustive list of anti-angiogenic molecules, and summarize their effects, where known, on the transcriptome and functional genomics of endothelial cells. The regulation of specific genes can be crucial to preventive or therapeutic intervention. Further, novel targets might help to circumvent resistance to anti-angiogenic therapy. The studies we review are relevant not only to cancer but also to other chronic degenerative diseases involving endothelial cells, such as cardiovascular disorders, diabetes, rheumatoid arthritis and retinopaties, as well as vessel aging.

The tissue inhibitors of metalloproteinases (TIMPs): an ancient family with structural and functional diversity

Tissue inhibitors of metalloproteinases (TIMPs) are widely distributed in the animal kingdom and the human genome contains four paralogous genes encoding TIMPs 1 to 4. TIMPs were originally characterized as inhibitors of matrix metalloproteinases (MMPs), but their range of activities has now been found to be broader as it includes the inhibition of several of the disintegrin-metalloproteinases, ADAMs and ADAMTSs. TIMPs are therefore key regulators of the metalloproteinases that degrade the extracellular matrix and shed cell surface molecules. Structural studies of TIMP-MMP complexes have elucidated the inhibition mechanism of TIMPs and the multiple sites through which they interact with target enzymes, allowing the generation of TIMP variants that selectively inhibit different groups of metalloproteinases. Engineering such variants is complicated by the fact that TIMPs can undergo changes in molecular dynamics induced by their interactions with proteases. TIMPs also have biological activities that are independent of metalloproteinases; these include effects on cell growth and differentiation, cell migration, anti-angiogenesis, anti- and pro-apoptosis, and synaptic plasticity. Receptors responsible for some of these activities have been identified and their signaling pathways have been investigated. A series of studies using mice with specific TIMP gene deletions has illuminated the importance of these molecules in biology and pathology.

High levels of serum TIMP-1 correlate with advanced disease and predict for poor survival in patients with multiple myeloma treated with novel agents

Tissue inhibitor of metalloproteinase-1 (TIMP-1) was evaluated in the pre-treatment serum of 55 newly diagnosed patients with symptomatic myeloma. TIMP-1 was elevated in 47% of patients and correlated with lytic bone disease and increased bone resorption. Importantly, TIMP-1 correlated with ISS stage (p=0.005) and was an independent prognostic covariate for survival [HR: 1.003 (1-1.006), p=0.004] in these patients who were all treated with novel agents (bortezomib and/or IMiDs) during their disease course. Our study provides evidence that pre-treatment serum TIMP-1 is associated with advanced myeloma and suggests the further evaluation of this molecule to better determine its prognostic potential in MM.

Activation of the endoplasmic reticulum stress-associated transcription factor x box-binding protein-1 occurs in a subset of normal germinal-center B cells and in aggressive B-cell lymphomas with prognostic implications

X box-binding protein 1 (Xbp-1) is a transcription factor that is required for the terminal differentiation of B lymphocytes into plasma cells. The Xbp-1 gene is activated in response to endoplasmic reticulum stress signals, which generate a 50-kDa nuclear protein that acts as a potent transactivator and regulates the expression of genes related to the unfolded protein response. Activated Xbp-1 is essential for cell survival in plasma-cell tumors but its role in B-cell lymphomas is unknown. We analyzed the expression of activated Xbp-1 in reactive lymphoid tissues, 411 lymphomas and plasma-cell neoplasms, and 24 B-cell lines. In reactive tissues, Xbp-1 was only found in nuclear extracts. Nuclear expression of Xbp-1 was observed in occasional reactive plasma cells and in a subpopulation of Irf-4(+)/Bcl-6(-)/Pax-5(-) B cells in the light zones of reactive germinal centers, probably representing cells committed to plasma-cell differentiation. None of the low-grade lymphomas showed evidence of Xbp-1 activation; however, Xbp-1 activation was found in 28% of diffuse large B-cell lymphomas, independent of germinal or postgerminal center phenotype, as well as in 48% of plasmablastic lymphomas and 69% of plasma-cell neoplasms. Diffuse large B-cell lymphomas with nuclear Xbp-1 expression had a significantly worse response to therapy and shorter overall survival compared with negative tumors. These findings suggest that Xbp-1 activation may play a role in the pathogenesis of aggressive B-cell lymphomas.

TIMP1 induces CD44 expression and the activation and nuclear translocation of SHP1 during the late centrocyte/post-germinal center B cell differentiation

Tissue inhibitor of metalloproteinase-1 (TIMP1) is a survival factor of germinal center (GC) B cells, and its over-expression is correlated with aggressive B cell lymphomas and classical Hodgkin lymphomas. We previously demonstrated that TIMP1 down-regulates B-cell receptor and BCL6, and activates interleukins-6,-10 (ILs)/signal transducer and activator of transcription-3 (STAT3) signaling in GC B cells. The activation of ILs/STAT3 signaling can amplify CD44 function, and vice versa, and induce protein-tyrosine phosphatase SHP1 activity by a negative feedback mechanism. Here, we show that TIMP1 up-regulates cell surface CD44 (standard and variants 3 and 7-10) and induces the activity and nuclear localization of SHP1 in an Epstein Barr virus (EBV)-negative Burkitt lymphoma cell line, the neoplastic counterpart of GC centroblasts. These results suggest that TIMP1 functions as a differentiating and survival factor of GC B cells by modulating CD44 and SHP1 in the late centrocyte/post-GC stage, regardless of EBV infection.

Matrix metalloproteinases-1 and -2, and tissue inhibitor of metalloproteinase-2 production is abnormal in bone marrow stromal cells of multiple myeloma patients

We have investigated the production of metalloproteinases (MMP-1, MMP-2, MMP-9) and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in bone marrow stromal cells (BMSCs) of patients with multiple myeloma (MM) and a healthy control. The new findings of this paper is that BMSCs of the MM patients exhibited intrinsic MMP-1, MMP-2 and TIMP-2 overproduction. Production of MMP-1, TIMP-2 and activation of MMP-2 was additionally enhanced in co-cultures of BMSCs with RPMI8226 cells. The ratio between MMP-2 and TIMP-2 was significantly higher in BMSCs of the MM patients than in control. BMSCs of both the control and the MM patients exhibited the presence of MMP-9 latent form, but in co-cultures RPMI8226 cells were the main producers of this metalloproteinase.

The tumor microenvironment: regulation by MMP-independent effects of tissue inhibitor of metalloproteinases-2

Proteolytic remodeling of the extracellular matrix is an important component of disease progression in many chronic disease states and is the initiating event in the formation of the tumor microenvironment in cancer. It is the balance of extracellular matrix degrading enzymes, the matrix metalloproteinases (MMPs) and their endogenous inhibitors that determine the extent of tissue remodeling. Unchecked MMP activity can result in significant tissue damage, facilitate disease progression and is associated with host responses to pathologic injury such as angiogenesis and inflammation. The tissue inhibitors of metalloproteinases (TIMPs) have been shown to regulate MMP activity. However, recent findings demonstrate that the tissue inhibitor of metalloproteinases-2 (TIMP-2) inhibits the mitogenic response of human microvascular endothelial cells to growth factors, such as VEGF-A and FGF-2 in vitro and angiogenesis in vivo. The mechanism of this effect is independent of metalloproteinase inhibition. Our lab is the first to demonstrate a cell-surface signaling receptor for a member of the TIMP family and suggest that TIMP-2 functions to regulate cellular responses to growth factors. These new findings are discussed in terms of a model of TIMP-2 regulation of cellular functions in the tumor microenvironment.

Chemical genetic transcriptional fingerprinting for selectivity profiling of kinase inhibitors

The importance of protein kinases as a major class of drug targets across multiple diseases has generated a critical need for technologies that enable the identification of potent and selective kinase inhibitors. Bruton's tyrosine kinase (Btk) is a compelling drug target in multiple therapeutic areas, including systemic lupus erythematosus, asthma, rheumatoid arthritis, and B cell malignancies. We have combined potent, selective kinase inhibition through chemical genetics with gene expression profiling to identify a "fingerprint" of transcriptional changes associated with selective Btk kinase inhibition. The Btk transcriptional fingerprint shows remarkable relevance for Btk's biological roles and was used for functional selectivity profiling of two kinase inhibitor compounds. The fingerprint was able to rank the compounds by relative selectivity for Btk, and revealed broader off-target effects than observed in a broad panel of biochemical kinase cross screens. In addition to being useful for functional selectivity profiling, the fingerprint genes are themselves potential preclinical and clinical biomarkers for developing Btk-directed therapies.

Tissue inhibitor of metalloproteinase-1 promotes hematopoietic differentiation via caspase-3 upstream the MEKK1/MEK6/p38alpha pathway

Besides its matrix metalloproteinases inhibitory activity, TIMP-1 exhibits other biological activities such as cell survival and proliferation. The intracellular signalling pathway elicited by TIMP-1 begins to be elucidated. We have shown previously that the caspase-3 and the p38alpha MAP kinase were activated during TIMP-1-induced UT-7 cells erythroid differentiation. In this study, we demonstrated that TIMP-1 differentiating effect can be extended to the IL-3-dependent myeloid murine 32D cell line and human erythroid progenitors derived from cord blood CD34(+) cells. By performing small interfering RNA transfection and using chemical inhibitors, we evidenced that caspase-3 was involved in TIMP-1 differentiating effect. We then identified the MEKK1 kinase as a caspase-3 substrate and demonstrated that the MEKK1/MEK6/p38alpha pathway was activated downstream the caspase-3 in TIMP-1-induced hematopoietic differentiation.

Signal transducers and activators of transcription-3 up-regulates tissue inhibitor of metalloproteinase-1 expression and decreases invasiveness of breast cancer

Signal transducers and activators of transcription (STAT)-3 is an oncogenic protein that is constitutively activated in many human cancers, including 30 to 60% of primary breast cancer. The biological significance of STAT3 activation in breast cancer is not fully understood. We have previously shown that STAT3 up-regulates tissue inhibitors of metalloproteinase (TIMP)-1, a cytokine known to block metalloproteinases and decrease invasiveness in certain cancer cell types. We hypothesize that STAT3 activation may modulate tumor invasiveness of breast cancer by regulating TIMP1 expression. Using MCF-7 cells transfected with tetracycline-off STAT3C (constitutively active STAT3), we generated an in vitro system in which STAT3C levels can be tightly controlled in breast cancer cells. Increasing tetracycline levels gradually decreased STAT3C and TIMP1 in a dose-dependent manner, and down-regulation of these proteins led to a reciprocal decrease in invasiveness of these cells in Matrigel. Addition of a neutralizing anti-TIMP1 antibody increased invasiveness in the same experimental system. Using immunohistochemistry and 142 primary breast tumors, we found a significant association between the expression of the phosphorylated/active form of STAT3 (pSTAT3) and that of TIMP1. Importantly, STAT3 activation correlated significantly with a lower frequency of vascular and lymphatic invasion (P = 0.015 and P = 0.0002, respectively). Our data support the concept that STAT3 activation significantly modulates the biological and clinical behavior of breast cancer.

Clinicopathologic implications of tissue inhibitor of metalloproteinase-1-positive diffuse large B-cell lymphoma

The tissue inhibitor of metalloproteinase-1 (TIMP-1) is a stromal factor that promotes plasmablastic differentiation, and the survival of germinal center B-cells. The expression of TIMP-1 is known to be correlated with a subset of non-Hodgkin lymphoma at the mRNA level, and Epstein-Barr virus infection in vitro. To characterize TIMP-1(+) diffuse large B-cell lymphoma, TIMP-1 expression was investigated in tissue microarrays from 182 cases of de novo diffuse large B-cell lymphoma and compared with prognostic factors, immunophenotypes, and Epstein-Barr virus infection status. TIMP-1 was expressed not only in tumor cells themselves, in 14 of 182 cases (8%), designated as TIMP-1(+) diffuse large B-cell lymphoma, but also in stromal cells like fibroblasts and endothelial cells. In univariate analysis and hierarchical clustering, our findings suggest that TIMP-1 expression may represent a distinct subgroup. In multivariate analysis, TIMP-1(+) diffuse large B-cell lymphoma (n=14) was associated with unfavorable outcomes compared to TIMP-1(-) diffuse large B-cell lymphoma (n=168) (odds ratio=2.5, P=0.049). Together with TIMP-1 expression, age (greater than 60 years), the presence of B-symptoms, abnormal lactate dehydrogenase level, or more advanced stage (III/IV) was correlated with a poor overall survival. However, TIMP-1 expression in diffuse large B-cell lymphoma was not correlated with other prognostic factors including: clinical stage, international prognostic index score, and nongerminal center B-cell phenotype, as well as Epstein-Barr virus infection. Our results suggest that TIMP-1 expression may be an independent negative prognostic factor in patients with diffuse large B-cell lymphoma.

TIMP-2 promotes cell spreading and adhesion via upregulation of Rap1 signaling

We previously demonstrated that TIMP-2 treatment of human microvascular endothelial cells (hMVECs) activates Rap1 via the pathway of paxillin-Crk-C3G. Here, we show that TIMP-2 overexpression in hMVECs by adenoviral infection enhances Rap1 expression, leading to further increase in Rap1-GTP. TIMP-2 expression, previously reported to inhibit cell migration, also leads to cell spreading accompanied with increased cell adhesion. HMVECs stably expressing Rap1 display a similar phenotype as hMVECs-TIMP-2, whereas the expression of inactive Rap1 mutant, Rap1(38N), leads to elongated appearance with greatly reduced cell adhesion. Furthermore, the phenotype of hMVECs-Rap1(38N) was not reversed by TIMP-2 overexpression. TIMP-2 greatly promotes the association of Rap1 with actin. Therefore, these findings suggest that TIMP-2 mediated alteration in cell morphology requires Rap1, TIMP-2 may recruit Rap1 to sites of actin cytoskeleton remodeling necessary for cell spreading, and enhanced cell adhesion by TIMP-2 expression may hinder cell migration.

Differential regulation of TIMP-1, -2, and -3 mRNA and protein expressions during mouse incisor development

Tissue inhibitors of metalloproteinases (TIMPs) possess multiple functions, in addition to their matrix metalloproteinase (MMP) inhibitory activity. The continuously growing incisor of mouse possesses a stem cell compartment at the apical end of the epithelium (the apical loop) and thus provides an excellent tool to analyze the mechanisms of organogenesis and cytodifferentiation. To understand the functions of TIMPs in tooth development, we have analyzed the gene expression and protein localization of TIMP-1, -2, and -3 during mouse incisor development, from embryonic day 13 (E13) to postnatal day 3 (P3). TIMP-1 was present on the basement membrane during early developmental stages. At P2, TIMP-1 was strongly detected along the apical loop, transiently disappeared from the basement membrane in the cytodifferentiation zone, and later reappeared at the distal end of functional ameloblasts. Expression of TIMP-2 protein was restricted to the outer part of the apical loop throughout the examined stages. At P2, TIMP-2 was present on the basement membrane at the outer part of the apical loop. The dental follicle also expressed Timp-2, and the corresponding protein was abundant within the extracellular matrix. Timp-3 mRNA was highly expressed in the mesenchyme surrounding the apical loop. During matrix formation, Timp-3 was expressed by subodontoblasts, and the protein was detected in this layer and between odontoblasts. Distinct temporal and spatial expression patterns of TIMPs suggest divergent functions of these factors in incisor organogenesis.

Diffuse large B-cell lymphomas with plasmablastic differentiation

Recent evidence suggests that diffuse large B-cell lymphoma (DLBCL) with plasmablastic differentiation represents a clinically heterogeneous spectrum with different clinicopathologic characteristics representing distinct entities. Subtypes of DLBCL with plasmablastic features and terminal B-cell differentiation include plasmablastic lymphoma (PBL) of oral mucosa type; PBL with plasmacytic differentiation; primary effusion lymphoma (PEL); KSHV-positive solid lymphoma/extracavitary PEL/HHV-8 associated DLBCL; and DLBCL expressing ALK. In contrast, PBL associated with multicentric Castleman disease, DLBCL with secretory differentiation, pyothorax-associated lymphoma, and atypical Burkitt lymphoma with plasmacytoid differentiation have morphologic appearances of plasma cell differentiation but maintain a mature B-cell (CD20 positive) phenotype. These tumors as well as extramedullary plasmablastic tumors secondary to multiple myeloma or plasmacytomas are included in the differential diagnosis. In this review, we discuss recently described clinicopathologic insights, case observations, and recently reported molecules involved in terminal B-cell or plasma cell differentiation and their possible roles in disease pathogenesis.