Matrix and serine protease expression during leukemic cell differentiation induced by aclacinomycin and all-trans-retinoic acid

Matrix metalloproteinase and its drug targets therapy in solid and hematological malignancies: an overview

Matrix metalloproteinase (MMP) comprises a family of zinc-dependent endopeptidases that degrade various components of the extracellular matrix (ECM) and basement membrane. MMPs are involved in solid and hematological malignancy through modification of cell growth, activation of cancer cells and modulation of immune functions. Several polymorphisms of different MMPs such as MMP-1 (-1607 1G/2G), MMP-2 (-1306 C/T), MMP-3 (-1171 5A/6A) & MMP-9 (-1562 C/T) and their expression levels have been well documented in different types of solid cancer. These polymorphic variations were found to be associated with angiogenesis, cancer progression, invasion and metastasis. There is paucity of data available in the field of hematological malignancies. Hence the field of matrix biology of hematological malignancies is an area of active exploration. A number of MMP inhibitors (MMPIs) have been developed for the cancer treatment. The most extensively studied classes of MMP inhibitors include Batimastat, Marismastat, Salimatat, Prinomastat and Tanomastat. However, their efficacy and action have not been confirmed and more data is required. The application of one or more selective targeted MMPIs in combination with conventional anti-leukemic treatment may represent a positive approach in combat against hematopoietic malignancies. Balance of MMPs and TIMPs is altered in different malignancies and biochemical pathways. These alternations will add another dimension in the matrix biology of both solid tumor and leukemia. MMP and TIMP singly and in combination are increasingly being recognized as an important player in basic cellular biology. Exploration and exploitation of MMP and TIMP balance in various malignant and nonmalignant lesions is going to be one of the most interesting facets of future use of this system for human health care.

Characterization of plasminogen binding to NB4 promyelocytic cells using monoclonal antibodies against receptor-induced binding sites in cell-bound plasminogen

The NB4 promyelocytic cell line exhibits many of the characteristics of acute promyelocytic leukemia blast cells, including the translocation (15 : 17) that fuses the PML gene on chromosome 15 to the RARα gene on chromosome 17. These cells have a very high fibrinolytic capacity. In addition to a high secretion of urokinase, NB4 cells exhibit a 10-fold higher plasminogen binding capacity compared with other leukemic cell lines. When tissue-type plasminogen activator was added to acid-treated cells, plasmin generation was 20–26-fold higher than that generated by U937 cells or peripheral blood neutrophils, respectively. We found that plasminogen bound to these cells can be detected by fluorescence-activated cell sorting using an antiplasminogen monoclonal antibody that specifically reacts with this antigen when it is bound to cell surfaces. All-trans retinoid acid treatment of NB4 cells markedly decreased the binding of this monoclonal antibody. This cell line constitutes a unique model to explore plasminogen binding and activation on cell surfaces that can be modulated by all-trans retinoid acid treatment.

Advances in understanding the pulmonary infiltration in acute promyelocytic leukaemia

In acute promyelocytic leukaemia (APL), differentiation therapy can be complicated by the development of a differentiation syndrome (DS). Pulmonary infiltration of differentiating leukaemic cells is a key event in the development of DS. Several mediators have been identified that may promote migration and extravasation of differentiating APL cells from the bloodstream into the tissue. Adhesion of APL cells to each other and to the endothelium is induced by upregulation of the expression of adhesion molecules and constitutively active β2-integrins during differentiation therapy. The expression of chemokines and their receptors is significantly upregulated as well. Pulmonary chemokine production can trigger transendothelial migration of differentiating APL cells from the bloodstream into the underlying tissue (initiation phase of DS). Massive production of chemokines by infiltrated APL cells can further enhance transendothelial migration of differentiating APL cells, causing an uncontrollable hyperinflammatory reaction in the lung (aggravation phase), which is not efficiently switched-off by corticosteroids.

The anti-invasive activity of synthetic alkaloid ethoxyfagaronine on L1210 leukemia cells is mediated by down-regulation of plasminogen activators and MT1-MMP expression and activity

Quaternary benzo[c]phenanthridines such as fagaronine are natural substances which have been reported to exhibit anticancer and anti-leukemic properties. However, the therapeutic use of these molecules is limited due to the high dose required to exhibit anti-tumor activity and subsequent toxicity. In this study, we describe the therapeutic potential of a new derivative of fagaronine, Ethoxyfagaronine (N-methyl-12-ethoxy-2hydroxy-3, 8, 9-trimethoxybenzo[c]-phenanthridiniumchlorhydrate) as an anti-leukemic agent. Cytotoxic activity and cell growth inhibition of Ethoxyfagaronine (Etxfag) was tested on murine L1210 leukemia cells using trypan blue assay and MTT assay. At the concentration of 10(-7) M, Etxfag induced less than 10% of cell death. Etxfag (10(-7) M) was tested on L1210 cell invasiveness using matrigel™ precoated transwell chambers and efficiently reduces the invasive potential of L1210 cells by more than 50% as compared with untreated cells. Western blot and immunofluorescence experiments showed that Etxfag decreased both MT1-MMP expression and activation at the cell surface, decreased plasmin activity by down-regulating u-PAR and uPA expression at the cell surface and increasing PAI-1 secretion in conditioned media. The set of our findings underscore the therapeutic potential of ethoxyfagaronine as a new potential anticancer agent able to prevent leukemic cell dissemination.

Extracellular matrix proteins protect human HT1080 cells against the antimigratory effect of doxorubicin

In solid tumors, the cell microenvironment appears to be a key determinant in the emergence of drug resistance, a major obstacle to the successful use of antitumor drugs. Our aim was to determine whether type I collagen and fibronectin, proteins of the extracellular matrix, were able to influence the antimigratory properties induced by the antitumor drug doxorubicin. These properties were investigated at doxorubicin concentrations of 10 and 20 nM, which do not affect cell proliferation on a 24 h drug exposure. Using videomicroscopy, we found that these subtoxic doses of doxorubicin were sufficient to inhibit individual tumor cell motion on two-dimensional plastic surfaces. Such a drug treatment induced a dramatic disturbance of actin stress fiber formation and of vinculin distribution in 80% of cells. In contrast, on extracellular matrix proteins, cell speed was unaffected by drug and perturbation of both actin network and vinculin distribution was detected in only 50% of cells, suggesting a protective effect of the microenvironment. In addition, the phosphorylation of focal adhesion kinase and GTPase RhoA was less affected by doxorubicin with cells cultured on extracellular matrix proteins. In conclusion, our findings indicate that the cell microenvironment prevents drug-dependent inhibition of cell migration in vitro. They reveal cell locomotion as a key factor of microenvironment-mediated drug resistance. This new concept needs to be exploited in in vitro models to optimize the screening of new antimigratory drugs.

Role of interleukin-8 and growth-regulated oncogene-α in the chemotactic migration of all-trans retinoic acid-treated promyelocytic leukemic cells toward alveolar epithelial cells*

OBJECTIVE

Although all-trans retinoic acid (ATRA) can treat acute promyelocytic leukemia (APL), it also causes retinoic acid syndrome with presentations similar to acute respiratory distress syndrome. We investigated the role of interleukin (IL)-8 and growth-regulated oncogene (GRO)-alpha in the chemotactic transmigration of ATRA-treated NB4 (ATRA-NB4) APL cells toward A549 alveolar epithelial cells.

DESIGN

An in vitro human cell culture study.

SETTING

University hospital research laboratories.

SUBJECTS

NB4 and A549 cells.

INTERVENTIONS

NB4 and A549 cells were separately cultured with ATRA and/or dexamethasone for 1-3 days. NB4 or ATRA-NB4 cells were then placed in an upper insert and co-incubated with A549 cells or their conditioned medium located in a lower plate.

MEASUREMENTS AND MAIN RESULTS

ATRA stimulated NB4 cells to transmigrate toward the A549 cells in a time- and dose-dependent manner. Replacement of A459 condition medium by its original medium abrogated this transmigration. Only A549 cells constitutively secreted GRO-alpha, and both A549 and NB4 cells constitutively secreted IL-8, which was enhanced by ATRA. Exogenous administration of IL-8 or GRO-alpha also promoted the ATRA-NB4 transmigration. The binding assay demonstrated that ATRA-NB4 cells bound IL-8, but not GRO-alpha, more avidly. Pretreatment with antibodies directed against IL-8 and GRO-alpha receptors reduced ATRA-NB4 transmigration by about 60%. Dexamethasone did not suppress their IL-8 secretion and transmigration in ATRA-NB4 cells, but when applied to A549 cells, IL-8 secretion was suppressed but not GRO-alpha secretion, and there was attenuation of ATRA-NB4 transmigration.

CONCLUSIONS

IL-8 and GRO-alpha secreted from alveolar epithelial cells play an important role in the cell-cell interaction involved in the chemotactic transmigration of ATRA-treated APL cells toward alveolar epithelial cells.

Matrix metalloproteinases of epithelial origin in facial sebum of patients with acne and their regulation by isotretinoin

Acne vulgaris is a skin disorder of the sebaceous follicles, involving hyperkeratinization and perifollicular inflammation. Matrix metalloproteinases (MMP) have a predominant role in inflammatory matrix remodeling and hyperproliferative skin disorders. We investigated the expression of MMP and tissue inhibitors of MMP (TIMP) in facial sebum specimens from acne patients, before and after treatment with isotretinoin. Gelatin zymography and Western-blot analysis revealed that sebum contains proMMP-9, which was decreased following per os or topical treatment with isotretinoin and in parallel to the clinical improvement of acne. Sebum also contains MMP-1, MMP-13, TIMP-1, and TIMP-2, as assessed by ELISA and western blot, but only MMP-13 was decreased following treatment with isotretinoin. The origin of MMP and TIMP in sebum is attributed to keratinocytes and sebocytes, since we found that HaCaT keratinocytes in culture secrete proMMP-2, proMMP-9, MMP-1, MMP-13, TIMP-1, and TIMP-2. SZ95 sebocytes in culture secreted proMMP-2 and proMMP-9, which was also confirmed by microarray analysis. Isotretinoin inhibited the arachidonic acid-induced secretion and mRNA expression of proMMP-2 and -9 in both cell types and of MMP-13 in HaCaT keratinocytes. These data indicate that MMP and TIMP of epithelial origin may be involved in acne pathogenesis, and that isotretinoin-induced reduction in MMP-9 and -13 may contribute to the therapeutic effects of the agent in acne.

Mycobacterial lipomannan induces matrix metalloproteinase-9 expression in human macrophagic cells through a Toll-like receptor 1 (TLR1)/TLR2- and CD14-dependent mechanism

Lipomannans (LM) from various mycobacterial species were found to induce expression and secretion of the matrix metalloproteinase 9 (MMP-9) both in human macrophage-like differentiated THP-1 cells and in primary human macrophages. Inhibition studies using antireceptor-neutralizing antibodies are indicative of a Toll-like receptor 1 (TLR1)/TLR2- and CD14-dependent signaling mechanism. Moreover, LM was shown to down-regulate transcription of the metalloproteinase inhibitor TIMP-1, a major endogenous MMP-9 regulator.

A RUNX/AML-binding motif residing in a novel 13-bp DNA palindrome may determine the expression of the proximal promoter of the human uPA gene

Urokinase-type plasminogen activator (uPA) is a multifunctional extracellular serine protease implicated in different events including fibrinolysis, tissue remodeling, and hematopoiesis. The human uPA gene contains a major promoter region at around 2000 bp upstream from the transcription start site (+1), and a second regulatory region spanning nucleotides -90/+32 within the proximal promoter. Here, an inspection of this region revealed a novel 13-bp palindrome residing at position +8/+20. Interestingly, the palindrome contains the DNA consensus-binding hexamer for the RUNX/AML family of transcription factors that play a role in hematopoiesis, leukemia, and several developmental processes. Measuring the expression for promoter-reporter constructs after transfection revealed that deletion of the palindrome abrogated most of the proximal promoter activity in 293A cell. Additionally, electrophoretic mobility shift assays have shown that the palindrome could bind the RUNX1 component in nuclear extracts of myeloid cell lines exclusively through its RUNX motif. The palindrome was found in five additional human genes, two of which (MYH11 and MLLT1) have been linked to chromosomal rearrangements leading to leukemia. The data presented here have implicated, for the first time, RUNX/AML in the regulation of the uPA gene. The significance of the novel palindrome regarding gene regulation through the RUNX motif deserves further investigation.

Matrix metalloproteinase activity and osteoclasts in experimental prostate cancer bone metastasis tissue

Previously, we and others showed that broad spectrum pharmaceutical inhibition of matrix metalloproteinase (MMP) activity reduces intraosseous tumor burden and bone degradation in animal models of bone metastasis. Herein, we used specific assays to measure net enzymatic activities of individual MMPs during colonization of bone by prostate cancer cells. PC3 cells were injected into the marrow of human fetal femurs previously implanted in SCID mice. Net MMP-9 activity in bone tissues peaked 2 weeks after injection, coinciding with a wave of osteoclast recruitment. In contrast, MMP-2 and MT1-MMP activity did not change. In vitro, co-culture of PC3 cells with bone tissue led to activation of pro-MMP-9 and increases in secreted net MMP-9 activity. Activation of pro-MMP-9 was prevented by metalloprotease inhibitors but not by inhibitors of other classes of proteases. Ribozyme suppression of MMP-9 expression in PC3 cells did not affect pro-MMP-9 activation or net MMP-9 activity and did not affect the phenotype of bone tumors. siRNA targeting of MMP-9 expression in preosteoclasts in vitro demonstrated that tumor-induced preosteoclast motility was dependent on MMP-9 expression. These data suggest that osteoclast-derived MMP-9 may represent a potential therapeutic target in bone metastasis and provide a rationale for the development of MMP-9-specific inhibitors.

Peroxisome proliferator activated receptor-γ ligands induced cell growth inhibition and its influence on matrix metalloproteinase activity in human myeloid leukemia cells

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is one of the best characterized nuclear hormone receptors (NHRs) in the superfamily of ligand-activated transcriptional factors. PPAR-gamma ligands have recently been demonstrated to affect proliferation, differentiation and apoptosis of different cell types. The present study was undertaken to investigate PPAR-gamma ligands induced cell growth inhibition and its influence on matrix metalloproteinase MMP-9 and MMP-2 activities on leukemia K562 and HL-60 cells in vitro. The results revealed that PPAR-gamma expression was detectable in the two kinds of leukemia cells; Both 15-deoxy-delta(12,14)-prostaglandin J2(15d-PGJ2) and troglitazone (TGZ) have significant growth inhibition effects on these two kinds of leukemia cells. These two PPAR-gamma ligands could inhibit the leukemic cell adhesion to the extracellular matrix (ECM) proteins and the invasion through matrigel matrix. The expressions of MMP-9 and MMP-2 as well as their gelatinolytic activities in both HL-60 and K562 cells were inhibited by 15d-PGJ2 and TGZ significantly. We therefore conclude that PPAR-gamma ligands 15d-PGJ2 and TGZ have significant growth inhibition effects on myeloid leukemia cells in vitro, and that PPAR-gamma ligands can inhibit K562 and HL-60 cell adhesion to and invasion through ECM as well as downregulate MMP-9 and MMP-2 expressions. The data suggest that PPAR-gamma ligands may serve as potential anti-leukemia reagents.

The possible role of matrix metalloproteinase (MMP)-2 and MMP-9 in cancer, e.g. acute leukemia

In the past decades, a lot of effort has been put in identifying the role of matrix metalloproteinases (MMPs) in cancer. The main role of MMPs in angiogenesis, tumor growth and metastasis is degradation of extracellular matrix (ECM) and release and/or activation of growth factors through their degradative activity. The degradative activity finally results in cancer progression. MMP-inhibitors (MMPIs) have already been designed and tested, based on the degradative role of MMPs in cancer progression. First clinical trials with MMPIs have been performed with disappointing results, showing that in order to use MMP-inhibition the mechanisms underlying MMP-expression in cancer have to be further elucidated. This paper reviews the mechanisms of MMPs on molecular and cellular level and discusses the role for MMPs and MMP-inhibition in cancer with special focus on acute leukemia.

Retinoic acid syndrome in NOD/scid mice induced by injecting an acute promyelocytic leukemia cell line

All-trans retinoic acid (ATRA) induces complete remission in patients with acute promyelocytic leukemia (APL). However, ATRA sometimes causes retinoic acid syndrome (RAS) characterized by respiratory distress, pleural effusions, fever and weight gain. To investigate the pathophysiology of RAS, we generated an animal model by injecting an APL cell line, NB4, into immunodeficient mice. When NOD/scid mice were injected intravenously with fully differentiated NB4 cells (1 x 10(7)) and then given a daily administration of ATRA, three of 12 mice died of pulmonary edema within 14 days. Pathologically, dilated lung capillary vessels and alveolar effusions were observed. After the injection, NB4 cells were detected in the lung within 2 days and in the pleural effusion later on. The gene expression levels of CXC chemokines (MIP-2 and KC) and ICAM-1 were increased in the lung and heart by the ATRA administration. In immunohistochemical analyses, MIP-2 was clearly detected in alveolar macrophages of the lung in mice with RAS. Dexamethasone treatment prevented the development of RAS and decreased the CXC chemokine mRNA expression in the lung. These findings suggested that the activation of adhesion molecules for leukocytes and expression of CXC chemokines in the lung are closely involved in triggering RAS.

PPARgamma ligands and ATRA inhibit the invasion of human breast cancer cells in vitro

Invasion and metastasis are the main causes of death in breast cancer patients. Increased expression of matrix metalloproteinases (MMPs), especially gelatinases (MMP-2 and -9), has been closely associated with tumor progression. One of the nuclear hormone receptors (NHR), peroxisome proliferator-activated receptor gamma (PPARgamma), is a ligand-activated transcriptional factor that regulates cell proliferation, differentiation and apoptosis in both normal and cancer cells. Recent data indicate that PPARgamma activation by its ligands can also lead to the inhibition of gelatinase B (MMP-9) and the blockage of migration in macrophages and muscle cells, implying the possibility that PPARgamma ligands may possess anti-invasive activities on tumor cells. In this study, we showed that treatment of the highly aggressive human breast cancer cell line MDA-MB-231 with the synthetic PPARgamma ligands pioglitazone (PGZ), rosiglitazone (RGZ), GW7845 or its natural ligand 15-deoxy-delta 12, 14-prostaglandin J2(15d-PGJ2), at concentrations at which no obvious cytotoxicity was observed in vitro, led to a significant inhibition of the invasive capacities of this cell line through a reconstituted basement membrane (Matrigel) in a Transwell chamber model. All-trans-retinoic acid (ATRA), a ligand for retinoic acid receptor (RAR), was also studied and showed a similar inhibitory effect on invasion. Although no change was observed in the expression of MMP-9 after challenge with PPARgamma ligands and/or ATRA on this cell line, the natural tissue inhibitor of gelatinases, namely the tissue inhibitor of MMP 1 (TIMP-1) was upregulated by these treatments and the gelatinolytic activities of gelatinases in the conditioned media were decreased. Since MMP-2 was not detectable in the conditioned media of MDA-MB-231 cells, and the gelatinolytic activities of the conditioned media were reduced only by MMP-9 neutralizing antibodies, it is most likely that the reduction of gelatinolytic activities by PPARgamma ligands and/or ATRA was due to the decrease of MMP-9 activities. Because MMP-9 was absolutely required in the transmigration of this cell line through Matrigel in our in vitro model as demonstrated by neutralizing antibodies against MMP-2 and -9, we concluded that down-regulation of gelatinase activities is, at least in part, responsible for the reduction of the invasive capacities of MDA-MB-231 cell line in vitro. Our results, for the first time, indicate that PPARgamma ligands may have therapeutic value for the treatment of highly invasive breast cancer by targeting its invasive behavior.

Butyric acid increases invasiveness of HL-60 leukemia cells: role of reactive oxygen species

Butyric acid (BA) induces differentiation of human leukemia, including HL-60 cells. By using a fluorescent probe, we showed that reactive oxygen species (ROS) were generated in BA-treated cells. BA-induced differentiation was accompanied with an increased secretion of pro-matrix metalloproteinase (MMP)-9. Both phenomena were inhibited by antioxidants. Tissue inhibitors of MMP (TIMP)-1 and -2 secretion were increased by BA, but differently affected by antioxidants. By contrast, BA did not affect MMP-9 mRNA, and decreased TIMP-1 and TIMP-2 mRNA levels. In addition, migratory and invasive properties of HL-60 cells were enhanced by BA, but differently affected by antioxidants. Altogether, these results indicate that ROS are messengers of BA-induced differentiation and increased invasiveness.