The role of matrix metalloproteinase 9 in the pathogenesis of chronic lymphocytic leukaemia

Biphenylsulfonamides as effective MMP-2 inhibitors with promising antileukemic efficacy: Synthesis, in vitro biological evaluation, molecular docking, and MD simulation analysis

Overexpression of matrix metalloproteinase-2 (MMP-2) possesses a correlation with leukemia especially chronic myeloid leukemia (CML). However, no such MMP-2 inhibitor has come out in the market to date for treating leukemia. In this study, synthesis, biological evaluation, and molecular modeling studies of a set of biphenylsulfonamide derivatives as promising MMP-2 inhibitors were performed, focusing on their potential applications as antileukemic therapeutics. Compounds DH-18 and DH-19 exerted the most effective MMP-2 inhibition (IC50 of 139.45 nM and 115.16 nM, respectively) with potent antileukemic efficacy against the CML cell line K562 (IC50 of 0.338 µM and 0.398 µM, respectively). The lead molecules DH-18 and DH-19 reduced the MMP-2 expression by 21.3% and 17.8%, respectively with effective apoptotic induction (45.4% and 39.8%, respectively) in the K562 cell line. Moreover, both these compounds significantly arrested different phases of the cell cycle. Again, both these molecules depicted promising antiangiogenic efficacy in the ACHN cell line. Nevertheless, the molecular docking and molecular dynamics (MD) simulation studies revealed that DH-18 formed strong bidentate chelation with the catalytic Zn2+ ion through the hydroxamate zinc binding group (ZBG). Apart from that, the MD simulation study also disclosed stable binding interactions of DH-18 and MMP-2 along with crucial interactions with active site amino acid residues namely His120, Glu121, His124, His130, Pro140, and Tyr142. In a nutshell, this study highlighted the importance of biphenylsulfonamide-based novel and promising MMP-2 inhibitors to open up a new avenue for potential therapy against CML.

The Role of the Microenvironment and Cell Adhesion Molecules in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a B-cell malignancy whose progression largely depends on the lymph node and bone marrow microenvironment. Indeed, CLL cells actively proliferate in specific regions of these anatomical compartments, known as proliferation centers, while being quiescent in the blood stream. Hence, CLL cell adhesion and migration into these protective niches are critical for CLL pathophysiology. CLL cells are lodged in their microenvironment through a series of molecular interactions that are mediated by cellular adhesion molecules and their counter receptors. The importance of these adhesion molecules in the clinic is demonstrated by the correlation between the expression levels of some of them, in particular CD49d, and the prognostic likelihood. Furthermore, novel therapeutic agents, such as ibrutinib, impair the functions of these adhesion molecules, leading to an egress of CLL cells from the lymph nodes and bone marrow into the circulation together with an inhibition of homing into these survival niches, thereby preventing disease progression. Several adhesion molecules have been shown to participate in CLL adhesion and migration. Their importance also stems from the observation that they are involved in promoting, directly or indirectly, survival signals that sustain CLL proliferation and limit the efficacy of standard and novel chemotherapeutic drugs, a process known as cell adhesion-mediated drug resistance. In this respect, many studies have elucidated the molecular mechanisms underlying cell adhesion-mediated drug resistance, which have highlighted different signaling pathways that may represent potential therapeutic targets. Here, we review the role of the microenvironment and the adhesion molecules that have been shown to be important in CLL and their impact on transendothelial migration and cell-mediated drug resistance. We also discuss how novel therapeutic compounds modulate the function of this important class of molecules.

Lipocalin-2 as a biomarker for diabetic nephropathy

Diabetes is a major global public health issue. The prevalence of type 1 diabetes is comparatively static, as hereditary and genetic causes are involved, while type 2 diabetes (T2D) prevalence is increasing day by day. T2D is associated with chronic complications, including diabetic neuropathy (DN), nephropathy, retinopathy, and other complications like diabetic foot. DN is the main complication of both types of diabetes. DN can be diagnosed by routine laboratory tests, microalbuminuria > 300 mg/24 h, and a gradual decrease in glomerular filtration rate. As the appearance of microalbuminuria is a late manifestation, an early marker for renal damage is needed. Lipocalin-2, also known as neutrophil gelatinase-associated lipocalin (NGAL), is a small protein purified from neutrophil granules and a good marker for kidney disease. NGAL is a transporter protein responsible for many physiological processes, such as inflammation, generation of the immune response, and metabolic homeostasis. NGAL has been reported to depict the early changes in renal damage when urine microalbumin is still undetecable. Therefore, elucidating the role of NGAL in detecting DN and understanding its mechanism can help establish it as a potential early marker for DN.

Metalloproteinase inhibition reduces AML growth, prevents stem cell loss, and improves chemotherapy effectiveness

Acute myeloid leukemia (AML) is a blood cancer of the myeloid lineage. Its prognosis remains poor, highlighting the need for new therapeutic and precision medicine approaches. AML symptoms often include cytopenias linked to loss of healthy hematopoietic stem and progenitor cells (HSPCs). The mechanisms behind HSPC decline are complex and still poorly understood. Here, intravital microscopy (IVM) of a well-established experimental model of AML allows direct observation of the interactions between healthy and malignant cells in the bone marrow (BM), suggesting that physical dislodgment of healthy cells by AML through damaged vasculature may play an important role. Multiple matrix metalloproteinases (MMPs), known to remodel extracellular matrix, are expressed by AML cells and the BM microenvironment. We reason MMPs could be involved in cell displacement and vascular leakiness; therefore, we evaluate the therapeutic potential of MMP pharmacological inhibition using the broad-spectrum inhibitor prinomastat. IVM analyses of prinomastat-treated mice reveal reduced vascular permeability and healthy cell clusters in circulation and lower AML infiltration, proliferation, and cell migration. Furthermore, treated mice have increased retention of healthy HSPCs in the BM and increased survival following chemotherapy. Analysis of a human AML transcriptomic database reveals widespread MMP deregulation, and human AML cells show susceptibility to MMP inhibition. Overall, our results suggest that MMP inhibition could be a promising complementary therapy to reduce AML growth and limit HSPC loss and BM vascular damage caused by MLL-AF9 and possibly other AML subtypes.

C-C Chemokine Receptor 7 in Cancer

C-C chemokine receptor 7 (CCR7) was one of the first two chemokine receptors that were found to be upregulated in breast cancers. Chemokine receptors promote chemotaxis of cells and tissue organization. Since under homeostatic conditions, CCR7 promotes migration of immune cells to lymph nodes, questions immediately arose regarding the ability of CCR7 to direct migration of cancer cells to lymph nodes. The literature since 2000 was examined to determine to what extent the expression of CCR7 in malignant tumors promoted migration to the lymph nodes. The data indicated that in different cancers, CCR7 plays distinct roles in directing cells to lymph nodes, the skin or to the central nervous system. In certain tumors, it may even serve a protective role. Future studies should focus on defining mechanisms that differentially regulate the unfavorable or beneficial role that CCR7 plays in cancer pathophysiology, to be able to improve outcomes in patients who harbor CCR7-positive cancers.

Leukaemia: a model metastatic disease

In contrast to solid cancers, which often require genetic modifications and complex cellular reprogramming for effective metastatic dissemination, leukaemic cells uniquely possess the innate ability for migration and invasion. Dedifferentiated, malignant leukocytes retain the benign leukocytes' capacity for cell motility and survival in the circulation, while acquiring the potential for rapid and uncontrolled cell division. For these reasons, leukaemias, although not traditionally considered as metastatic diseases, are in fact models of highly efficient metastatic spread. Accordingly, they are often aggressive and challenging diseases to treat. In this Perspective, we discuss the key molecular processes that facilitate metastasis in a variety of leukaemic subtypes, the clinical significance of leukaemic invasion into specific tissues and the current pipeline of treatments targeting leukaemia metastasis.

Internal Disulfide Bonding and Glycosylation of Interleukin-7 Protect Against Proteolytic Inactivation by Neutrophil Metalloproteinases and Serine Proteases

Interleukin 7 (IL-7) is a cell growth factor with a central role in normal T cell development, survival and differentiation. The lack of IL-7–IL-7 receptor(R)-mediated signaling compromises lymphoid development, whereas increased signaling activity contributes to the development of chronic inflammation, cancer and autoimmunity. Gain-of-function alterations of the IL-7R and the signaling through Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) are enriched in T cell acute lymphoblastic leukemia (T-ALL) and autocrine production of IL-7 by T-ALL cells is involved in the phenotypes of leukemic initiation and oncogenic spreading. Several IL-7-associated pathologies are also characterized by increased presence of matrix metalloproteinase-9 (MMP-9), due to neutrophil degranulation and its regulated production by other cell types. Since proteases secreted by neutrophils are known to modulate the activity of many cytokines, we investigated the interactions between IL-7, MMP-9 and several other neutrophil-derived proteases. We demonstrated that MMP-9 efficiently cleaved human IL-7 in the exposed loop between the α-helices C and D and that this process is delayed by IL-7 N-linked glycosylation. Functionally, the proteolytic cleavage of IL-7 did not influence IL-7Rα binding and internalization nor the direct pro-proliferative effects of IL-7 on a T-ALL cell line (HPB-ALL) or in primary CD8⁺ human peripheral blood mononuclear cells. A comparable effect was observed for the neutrophil serine proteases neutrophil elastase, proteinase 3 and combinations of neutrophil proteases. Hence, glycosylation and disulfide bonding as two posttranslational modifications influence IL-7 bioavailability in the human species: glycosylation protects against proteolysis, whereas internal cysteine bridging under physiological redox state keeps the IL-7 conformations as active proteoforms. Finally, we showed that mouse IL-7 does not contain the protease-sensitive loop and, consequently, was not cleaved by MMP-9. With the latter finding we discovered differences in IL-7 biology between the human and mouse species.

Relation of Neutrophil Gelatinase-Associated Lipocalin Overexpression to the Resistance to Apoptosis of Tumor B Cells in Chronic Lymphocytic Leukemia

The resistance to apoptosis of chronic lymphocytic leukemia (CLL) cells partly results from the deregulated production of survival signals from leukemic cells. Despite the development of new therapies in CLL, drug resistance and disease relapse still occur. Recently, neutrophil gelatinase-associated lipocalin (NGAL), a secreted glycoprotein, has been suggested to have a critical role in the biology of tumors. Thus, we investigated the relevance of NGAL in CLL pathogenesis, analyzed the expression of its cellular receptor (NGAL-R) on malignant B cells and tested whether CLL cells are resistant to apoptosis through an autocrine process involving NGAL and NGAL-R. We observed that NGAL concentrations were elevated in the serum of CLL patients at diagnosis. After treatment (and regardless of the therapeutic regimen), serum NGAL levels normalized in CLL patients in remission but not in relapsed patients. In parallel, NGAL and NGAL-R were upregulated in leukemic cells from untreated CLL patients when compared to normal peripheral blood mononuclear cells (PBMCs), and returned to basal levels in PBMCs from patients in remission. Cultured CLL cells released endogenous NGAL. Anti-NGAL-R antibodies enhanced NGAL-R⁺ leukemia cell death. Conversely, recombinant NGAL protected NGAL-R⁺ CLL cells against apoptosis by activating a STAT3/Mcl-1 signaling pathway. Our results suggest that NGAL and NGAL-R, overexpressed in untreated CLL, participate in the deregulation of the apoptotic machinery in CLL cells, and may be potential therapeutic clues for CLL treatment.

Increased levels of the cardiovascular disease risk biomarkers GDF15 and myostatin in patients with chronic lymphocytic leukemia

Individuals suffering from cancer, including hematological malignancies, are at increased risk of cardiovascular disease (CVD). Elevated levels of several biomarkers in blood are associated with an increased risk of CVD. The aim of this study was to investigate whether a subset of such CVD risk biomarkers was elevated in patients with untreated chronic lymphocytic leukemia (CLL). Blood plasma and serum from 139 CLL patients and 71 healthy age-matched controls were analyzed for 11 proposed CVD risk biomarkers. The CLL cohort displayed a more heterogeneous pattern of biomarker expression compared to controls. The majority, eight out of 11, analyzed CVD risk biomarkers differed significantly in concentrations between CLL patients and controls. Increased levels of the biomarkers GDF15 and myostatin have not previously been reported in CLL. Further prospective studies are warranted to investigate whether these biomarkers predict future cardiovascular events in patients with CLL.

Tumor-stroma interaction increases CD147 expression in neoplastic B lymphocytes in chronic lymphocytic leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) microenvironment plays a critical role in disease pathogenesis. Matrix metalloproteinases (MMPs) are involved in CLL-B cell migration and survival. CD147 is associated with MMPs production by tumor and stromal cells.

AIM

To analyze CD147, MMP2 and MMP9 expression in CLL-B cells and its modulation by fibroblasts (Fb)-CLL-B cell interaction.

METHODS

CLL-B cells were co-cultured with Fb, as a simulation of CLL microenvironment. CD147 was evaluated in healthy donor (HD)-B cells and CLL-B cells by flow cytometry. MMP2 and MMP9 activity in CLL-plasma samples and conditioned media (CMs) was studied by zymography.

RESULTS

MMP9/MMP2 plasma levels were significantly higher in CLL patients than in HD. CD147 expression (median fluorescence intensity) in CLL patients characterized 3 groups: low- (19.1 ± 3.2; n=3), middle- (42.7 ± 12.8; n=18) and high- (76.5 ± 9.6; n=5) related to CD147 expression in HD-B cells. CD147 expression significantly increased in CLL-B cells after Fb-CLL-B cell co-culture. A significant increase in proMMP2 activity was observed in CMs obtained from Fb-CLL-B cell co-cultures in comparison with isolated CLL-B cells.

CONCLUSIONS

CD147 expression in CLL-B cells and MMPs secretion was induced by Fb-CLL-B cell contact, suggesting CD147 participation in the CLL pathophysiology.

Iron and leukemia: new insights for future treatments

Iron, an indispensable element for life, is involved in all kinds of important physiological activities. Iron promotes cell growth and proliferation, but it also causes oxidative stress damage. The body has a strict regulation mechanism of iron metabolism due to its potential toxicity. As a cancer of the bone marrow and blood cells, leukemia threatens human health seriously. Current studies suggest that dysregulation of iron metabolism and subsequent accumulation of excess iron are closely associated with the occurrence and progress of leukemia. Specifically, excess iron promotes the development of leukemia due to the pro-oxidative nature of iron and its damaging effects on DNA. On the other hand, leukemia cells acquire large amounts of iron to maintain rapid growth and proliferation. Therefore, targeting iron metabolism may provide new insights for approaches to the treatment of leukemia. This review summarizes physiologic iron metabolism, alternations of iron metabolism in leukemia and therapeutic opportunities of targeting the altered iron metabolism in leukemia, with a focus on acute leukemia.

Dissecting the Prognostic Significance and Functional Role of Progranulin in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is known for its strong dependency on the tumor microenvironment. We found progranulin (GRN), a protein that has been linked to inflammation and cancer, to be upregulated in the serum of CLL patients compared to healthy controls, and increased GRN levels to be associated with an increased hazard for disease progression and death. This raised the question of whether GRN is a functional driver of CLL. We observed that recombinant GRN did not directly affect viability, activation, or proliferation of primary CLL cells in vitro. However, GRN secretion was induced in co-cultures of CLL cells with stromal cells that enhanced CLL cell survival. Gene expression profiling and protein analyses revealed that primary mesenchymal stromal cells (MSCs) in co-culture with CLL cells acquire a cancer-associated fibroblast-like phenotype. Despite its upregulation in the co-cultures, GRN treatment of MSCs did not mimic this effect. To test the relevance of GRN for CLL in vivo, we made use of the Eμ-TCL1 CLL mouse model. As we detected strong GRN expression in myeloid cells, we performed adoptive transfer of Eμ-TCL1 leukemia cells to bone marrow chimeric Grn-/- mice that lack GRN in hematopoietic cells. Thereby, we observed that CLL-like disease developed comparable in Grn-/- chimeras and respective control mice. In conclusion, serum GRN is found to be strongly upregulated in CLL, which indicates potential use as a prognostic marker, but there is no evidence that elevated GRN functionally drives the disease.

Expression and Activity of Matrix Metalloproteinases in Leukemia

Matrix metalloproteinases (MMPs) are responsible for the degradation of extracellular matrix components and hence play a crucial role in physiological and pathologic processes. The imbalance between the expression of MMPs and their inhibitors can be effective in leukemic cell processes such as migration, angiogenesis, survival, and apoptosis, playing a key role in the progression and prognosis of leukemia. In this review, we discuss the potential involvement of MMPs and their inhibitors in the pathogenesis and progression of leukemia by examining their role in the prognosis of leukemia. Inducing leukemic cell growth, migration, invasiveness, and angiogenesis are the main roles of MMPs in leukemia progression mediated by their degradative activity. Given the important role of MMPs in leukemia progression, further clinical trials are needed to confirm the link between MMPs' expressions and leukemia prognosis. It is hoped to use MMPs as therapeutic targets to improve patients' health by recognizing the prognostic value of MMPs in leukemia and their effect on the progression of these malignancies and their response to treatment.

Molecular Players in Hematologic Tumor Cell Trafficking

The trafficking of neoplastic cells represents a key process that contributes to progression of hematologic malignancies. Diapedesis of neoplastic cells across endothelium and perivascular cells is facilitated by adhesion molecules and chemokines, which act in concert to tightly regulate directional motility. Intravital microscopy provides spatio-temporal views of neoplastic cell trafficking, and is crucial for testing and developing therapies against hematologic cancers. Multiple myeloma (MM), chronic lymphocytic leukemia (CLL), and acute lymphoblastic leukemia (ALL) are hematologic malignancies characterized by continuous neoplastic cell trafficking during disease progression. A common feature of these neoplasias is the homing and infiltration of blood cancer cells into the bone marrow (BM), which favors growth and survival of the malignant cells. MM cells traffic between different BM niches and egress from BM at late disease stages. Besides the BM, CLL cells commonly home to lymph nodes (LNs) and spleen. Likewise, ALL cells also infiltrate extramedullary organs, such as the central nervous system, spleen, liver, and testicles. The α4β1 integrin and the chemokine receptor CXCR4 are key molecules for MM, ALL, and CLL cell trafficking into and out of the BM. In addition, the chemokine receptor CCR7 controls CLL cell homing to LNs, and CXCR4, CCR7, and CXCR3 contribute to ALL cell migration across endothelia and the blood brain barrier. Some of these receptors are used as diagnostic markers for relapse and survival in ALL patients, and their level of expression allows clinicians to choose the appropriate treatments. In CLL, elevated α4β1 expression is an established adverse prognostic marker, reinforcing its role in the disease expansion. Combining current chemotherapies with inhibitors of malignant cell trafficking could represent a useful therapy against these neoplasias. Moreover, immunotherapy using humanized antibodies, CAR-T cells, or immune check-point inhibitors together with agents targeting the migration of tumor cells could also restrict their survival. In this review, we provide a view of the molecular players that regulate the trafficking of neoplastic cells during development and progression of MM, CLL, and ALL, together with current therapies that target the malignant cells.

Revisiting Neutrophil Gelatinase-Associated Lipocalin (NGAL) in Cancer: Saint or Sinner?

Human neutrophil gelatinase-associated lipocalin (NGAL) is a glycoprotein present in a wide variety of tissues and cell types. NGAL exists as a 25 kDa monomer, a 46 kDa homodimer (the most abundant form in healthy subjects) and a 130 kDa disulfide-linked heterodimer bound to latent matrix metalloproteinase-9. Dysregulated expression of NGAL in human malignancies suggests its value as a clinical marker. A growing body of evidence is highlighting NGAL’s paradoxical (i.e., both beneficial and detrimental) effects on cellular processes associated with tumor development (proliferation, survival, migration, invasion, and multidrug resistance). At least two distinct cell surface receptors are identified for NGAL. This review (i) summarizes our current knowledge of NGAL’s expression profiles in solid tumors and leukemias, and (ii) critically evaluates the beneficial and detrimental activities of NGAL having been documented in a diverse range of cancer-derived cell lines. A better understanding of the causal relationships between NGAL dysregulation and tumor development will require a fine analysis of the molecular aspects and biological role(s) of NGAL both in primary tumors and at different stages of disease. Having an accurate picture of NGAL’s contribution to tumor progression is a prerequisite for attempting to modulate this protein as a putative therapeutic target.

[Regulation of Ruxolitinib on matrix metalloproteinase in JAK2V617F positive myeloroliferative neoplasms cells]

Objective: To investigate the regulation of JAK2 tyrosine kinase inhibitor ruxolitinib on extracellular matrix metalloproteinase (MMP in JAK2V617F positive myeloproliferative neoplasms (MPN) cells. Methods: ①Forty cases of newly diagnosed JAK2V617F positive MPN patients and 15 healthy volunteers as control in Baoding No.1 Hospital between January 2012 and December 2015 were enrolled in this study. JAK2V617F/JAK2 ratio was detected by real-time-PCR; the expression levels of phosphorylation protein tyrosine kinase 2 (p-JAK2) , MMP-2 and MMP-9 in pathological tissues of bone marrow were detected by immunohistochemistry. The bone marrow cells of JAK2V617F positive MPN patients were treated with ruxolitinib, then the migration ability and MMP-2, MMP-9 gene and protein expression levels were detected. ②The human erythroleukemia cell line HEL cells were treated with different concentrations of ruxolitinib (0, 50, 100, 250, 500, 1 000 nmol/L) . The cell viability was detected by CCK-8 test; cell migration ability was tested by transwell chambers. The mRNA expression levels of JAK2, MMP-2 and MMP-9 were detected by real-time-PCR. The protein expression levels of p-JAK2, MMP-2 and MMP-9 were detected by Western blot. Results: ①The expression levels of p-JAK2, MMP-2 and MMP-9 in the newly diagnosed group were significantly higher than control group respectively [ (78.56±24.55) % vs (41.59±17.29) %, P<0.05; (48.25±18.74) % vs (22.79±13.89) %, P<0.05; (53.29±19.28) % vs (15.56±14.96) %, P<0.05]. Spearman correlation analysis showed the positive correlation of MMP-2 and MMP-9 protein expression levels with JAK2V617F mutation (r=0.526, P=0.001; r=0.543, P=0.001) . ②The proliferation of HEL cells was inhibited by different concentrations of ruxolitinib in time and dose dependent manner. ③Cell migration test showed the number of cells leaked to the low chamber in MPN patients bone marrow cells and HEL cells treated with 5 nmol/L of ruxolitinib group were significantly lower than that without ruxolitinib treatment after 24 h [ (154.7±27.5) vs (320.3±67.3) , t=13.47, P<0.05; (70.7±10.5) vs (135.3±16.7) , t=13.89, P<0.05]. The mRNA and protein expression levels of JAK2, MMP-2 and MMP-9 decreased with the increased concentration of ruxolitinib. Conclusion: Ruxolitinib inhibits MPN cell migration and expression of MMP-2 and MMP-9 via JAK2 signal pathway.

S100-A9 protein in exosomes from chronic lymphocytic leukemia cells promotes NF-κB activity during disease progression

Plasma-derived exosomes from patients with CLL exhibit different protein cargo compositions depending on disease status and progression. S100-A9 protein is overexpressed and S100-A9 cargo in exosomes activates NF-κB pathway in patients with CLL during disease progression.

Proteome analysis of sheep B lymphocytes in the course of bovine leukemia virus-induced leukemia

Presented are the results of a study of the expression pattern of different proteins in the course of bovine leukemia virus-induced leukemia in experimental sheep and I discuss how the obtained data may be useful in gaining a better understanding of the pathogenesis of the disease, diagnosis, and for the selection of possible therapeutic targets. In cattle, the disease is characterized by life-long persistent lymphocytosis leading to leukemia/lymphoma in about 5% of infected animals. In sheep, as opposed to cattle, the course of the disease is always fatal and clinical symptoms usually occur within a three-year period after infection. For this reason, sheep are an excellent experimental model of retrovirus-induced leukemia. This model can be useful for human pathology, as bovine leukemia virus is closely related to human T-lymphotropic virus type 1. The data presented here provide novel insights into the molecular mechanisms of the bovine leukemia virus-induced tumorigenic process and indicate the potential marker proteins both for monitoring progression of the disease and as possible targets of pharmacological intervention. A study of the proteome of B lymphocytes from four leukemic sheep revealed 11 proteins with altered expression. Among them, cytoskeleton and intermediate filament proteins were the most abundant, although proteins belonging to the other functional groups, i.e. enzymes, regulatory proteins, and transcription factors, were also present. It was found that trypsin inhibitor, platelet factor 4, thrombospondin 1, vasodilator-stimulated phosphoprotein, fibrinogen alpha chain, zyxin, filamin-A, and vitamin D-binding protein were downregulated, whereas cleavage and polyadenylation specificity factor subunit 5, non-POU domain-containing octamer-binding protein and small glutamine-rich tetratricopeptide repeat-containing protein alpha were upregulated. Discussed are the possible mechanisms of their altered expression and its significance in the bovine leukemia virus-induced leukemogenic process. Impact statement The submitted manuscript provides new data on the molecular mechanisms of BLV-induced tumorigenic process indicating the potential marker proteins both for monitoring the progression of the disease and as possible targets of pharmacological intervention. This is to my knowledge the first study of the proteome of the transformed lymphocytes in the course of bovine leukemia virus-induced leukemia in susceptible animals. BLV can be considered as useful model for related human pathogen - HTLV-1, another member of the deltaretrovirus genus evolutionary closely related to BLV. Information gathered in this study can be useful to speculate on possible shared mechanisms of deltaretrovirus-induced carcinogenesis.

Plasma matrix metalloprotease 9 correlates with blood lymphocytosis, leukemic cell invasiveness, and prognosis in B-cell chronic lymphocytic leukemia

The complex biology underlying chronic lymphocytic leukemia cell migration and tissue invasiveness is not yet completely understood and might provide novel predictive markers and therapeutic targets. A total of 36 patients out of treatment from at least 3 months were enrolled and followed up for a median period of 44.2 months (range: 4.4–99.2). Matrix metalloprotease 9 and tissue inhibitor of metalloproteases 1 plasma levels and production/release from lymphoid cells were measured by zymography and enzyme-linked immunosorbent assay (ELISA) analysis. Malignant and normal lymphocyte mobility and matrix-degradation capability were studied using a Boyden chamber system, with and without autologous plasma. Free matrix metalloprotease 9 plasma levels were related with blood lymphocytosis, especially in more advanced stages (p = 0.003), and higher concentrations were associated with an increased disease progression risk (hazard ratio = 9.0, 95% confidence interval = 1.5–13.8). Leukemic cells expressed and secreted very little matrix metalloprotease 9. On the contrary, normal lymphocytes derived from the same leukemic patients showed matrix metalloprotease 9 intracellular levels that were lower in subjects with higher blood lymphocytosis (p = 0.024) and more advanced stages (p = 0.03); the released quantities were inversely associated with matrix metalloprotease 9 plasma concentrations (p = 0.035). Leukemic cells had a reduced spontaneous mobility and matrix-degradation capability that were stimulated by autologous plasma (p = 0.001) and normal lymphocytes (p = 0.005), respectively. Matrix metalloprotease 9 affected cell invasiveness depending on concentration and disease stage. In conclusion, chronic lymphocytic leukemia cells have a reduced mobility, matrix-degradation capability, and matrix metalloprotease 9 production compared to their own autologous normal lymphocytes. They are exposed to matrix metalloprotease 9 of prevalently systemic origin whose higher levels are associated with both leukemic and normal lymphocyte accumulation in the peripheral blood and have a negative prognostic value.

The Human CD38 Monoclonal Antibody Daratumumab Shows Antitumor Activity and Hampers Leukemia-Microenvironment Interactions in Chronic Lymphocytic Leukemia

Purpose: To establish a proof-of-concept for the efficacy of the anti-CD38 antibody daratumumab in the poor prognosis CD38⁺ chronic lymphocytic leukemia (CLL) subtype.Experimental Design: The mechanism of action of daratumumab was assessed in CLL primary cells and cell lines using peripheral blood mononuclear cells to analyze antibody-dependent cell cytotoxicity (ADCC), murine and human macrophages to study antibody-dependent cell phagocytosis (ADCP), or human serum to analyze complement-dependent cytotoxicity (CDC). The effect of daratumumab on CLL cell migration and adhesion to extracellular matrix was characterized. Daratumumab activity was validated in two in vivo models.Results: Daratumumab demonstrated efficient lysis of patient-derived CLL cells and cell lines by ADCC in vitro and ADCP both in vitro and in vivo whereas exhibited negligible CDC in these cells. To demonstrate the therapeutic effect of daratumumab in CLL, we generated a disseminated CLL mouse model with the CD38⁺ MEC2 cell line and CLL patient-derived xenografts (CLL-PDX). Daratumumab significantly prolonged overall survival of MEC2 mice, completely eliminated cells from the infiltrated organs, and significantly reduced disease burden in the spleen of CLL-PDX. The effect of daratumumab on patient-derived CLL cell dissemination was demonstrated in vitro by its effect on CXCL12-induced migration and in vivo by interfering with CLL cell homing to spleen in NSG mice. Daratumumab also reduced adhesion of CLL cells to VCAM-1, accompanied by downregulation of the matrix metalloproteinase MMP9.Conclusions: These unique and substantial effects of daratumumab on CLL viability and dissemination support the investigation of its use in a clinical setting of CLL. Clin Cancer Res; 23(6); 1493-505. ©2016 AACR.

Gene expression and splicing alterations analyzed by high throughput RNA sequencing of chronic lymphocytic leukemia specimens

Background

To determine differentially expressed and spliced RNA transcripts in chronic lymphocytic leukemia specimens a high throughput RNA-sequencing (HTS RNA-seq) analysis was performed.

Methods

Ten CLL specimens and five normal peripheral blood CD19+ B cells were analyzed by HTS RNA-seq. The library preparation was performed with Illumina TrueSeq RNA kit and analyzed by Illumina HiSeq 2000 sequencing system.

Results

An average of 48.5 million reads for B cells, and 50.6 million reads for CLL specimens were obtained with 10396 and 10448 assembled transcripts for normal B cells and primary CLL specimens respectively. With the Cuffdiff analysis, 2091 differentially expressed genes (DEG) between B cells and CLL specimens based on FPKM (fragments per kilobase of transcript per million reads and false discovery rate, FDR q < 0.05, fold change >2) were identified. Expression of selected DEGs (n = 32) with up regulated and down regulated expression in CLL from RNA-seq data were also analyzed by qRT-PCR in a test cohort of CLL specimens. Even though there was a variation in fold expression of DEG genes between RNA-seq and qRT-PCR; more than 90 % of analyzed genes were validated by qRT-PCR analysis. Analysis of RNA-seq data for splicing alterations in CLL and B cells was performed by Multivariate Analysis of Transcript Splicing (MATS analysis). Skipped exon was the most frequent splicing alteration in CLL specimens with 128 significant events (P-value <0.05, minimum inclusion level difference >0.1).

Conclusion

The RNA-seq analysis of CLL specimens identifies novel DEG and alternatively spliced genes that are potential prognostic markers and therapeutic targets. High level of validation by qRT-PCR for a number of DEG genes supports the accuracy of this analysis. Global comparison of transcriptomes of B cells, IGVH non-mutated CLL (U-CLL) and mutated CLL specimens (M-CLL) with multidimensional scaling analysis was able to segregate CLL and B cell transcriptomes but the M-CLL and U-CLL transcriptomes were indistinguishable. The analysis of HTS RNA-seq data to identify alternative splicing events and other genetic abnormalities specific to CLL is an added advantage of RNA-seq that is not feasible with other genome wide analysis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1708-9) contains supplementary material, which is available to authorized users.

BCR/ABL oncogene-induced PI3K signaling pathway leads to chronic myeloid leukemia pathogenesis by impairing immuno-modulatory function of hemangioblasts

An increasing number of studies indicate that during development, endothelial and hematopoietic cells derive from common progenitors named hemangioblasts that have important roles in the pathogenesis. This is particularly true in chronic myeloid leukemia (CML). Here, we isolated fetal liver kinase-1-positive (Flk1(+)) cells from CML patients and found they expressed BCR/ABL-specific CML oncogene. We examined their biological characteristics as well as immunological functions and further detected the possible molecular mechanism involved in the leukemia genesis. We showed that CML patient-derived Flk1(+)CD31(-)CD34(-) mesenchymal stem cells (MSCs) had normal morphology, phenotype and karyotype but appeared impaired immuno-modulatory function. The capacity of Flk1(+)CD31(-)CD34(-) MSCs from CML patients to inhibit T lymphocyte activation and proliferation was impaired in vitro. CML patient-derived MSCs have dampening immuno-modulatory functions, suggesting that the dysregulation of hematopoiesis and immune response might originate from MSCs rather than hematopoietic stem cells (HSCs). These Ph(+) putative CML hemangioblast upregulated TGF-β1 and resultantly activated matrix metalloproteinase-9 (MMP-9) to enhance s-KitL and s-ICAM-1 secretion, which activated c-kit(+) HSCs from the quiescent state to the proliferative state. Further studies showed that phosphatidylinositol-3 kinase (PI3K)/Akt/nuclear factor (NF)-κB signaling pathway was involved in CML pathogenesis. Flk1(+)CD31(-)CD34(-) MSCs that express BCR/ABL leukemia oncogene are hemangioblasts and they have a critical role in the progression of CML through PI3K/Akt/NF-κB signaling pathway.

A novel CD44-binding peptide from the pro-matrix metalloproteinase-9 hemopexin domain impairs adhesion and migration of chronic lymphocytic leukemia (CLL) cells

(pro)MMP-9 binds to CLL cells through the PEX9 domain and contributes to CLL progression. To biochemically characterize this interaction and identify potential therapeutic targets, we prepared GST-PEX9 forms containing structural blades B1B2 or B3B4. We recently described a sequence in blade B4 (P3 sequence) that bound α4β1 integrin and partially impaired cell adhesion and migration. We have now studied the possible contribution of the B1B2 region to cell interaction with PEX9. CLL cells bound to GST-B1B2 and CD44 was the primary receptor. GST-B1B2 inhibited CLL cell migration as effectively as GST-B3B4. Overlapping synthetic peptides spanning the B1B2 region identified the sequence FDAIAEIGNQLYLFKDGKYW, present in B1 and contained in peptide P6, as the most effective site. P6 inhibited cell adhesion to PEX9 in a dose-dependent manner and with an IC50 value of 90 μM. P6 also inhibited cell adhesion to hyaluronan but had no effect on adhesion to VCAM-1 (α4β1 integrin ligand), confirming its specific interaction with CD44. Spatial localization analyses mapped P6 to the central cavity of PEX9, in close proximity to the previously identified P3 sequence. Both P6 and P3 equally impaired cell adhesion to (pro)MMP-9. Moreover, P6 synergistically cooperated with P3, resulting in complete inhibition of CLL cell binding to PEX9, chemotaxis, and transendothelial migration. Thus, P6 is a novel sequence in PEX9 involved in cell-PEX9/(pro)MMP-9 binding by interacting with CD44. Targeting both sites, P6 and P3, should efficiently prevent (pro)MMP-9 binding to CLL cells and its pathological consequences.

The γ-secretase inhibitor PF-03084014 combined with fludarabine antagonizes migration, invasion and angiogenesis in NOTCH1-mutated CLL cells

Targeting Notch signaling has emerged as a promising therapeutic strategy for chronic lymphocytic leukemia (CLL), especially for the poor prognostic subgroup of NOTCH1-mutated patients. Here, we report that the γ-secretase inhibitor PF-03084014 inhibits the constitutive Notch activation and induces selective apoptosis in CLL cells carrying NOTCH1 mutations. Combination of PF-03084014 with fludarabine has a synergistic antileukemic effect in primary NOTCH1-mutated CLL cells, even in the presence of the protective stroma. At transcriptional level, PF-03084014 plus fludarabine treatment induces the upregulation of the proapoptotic gene HRK and the downmodulation of MMP9, IL32 and RAC2 genes that are related to invasion and chemotaxis. PF-03084014 also overcomes fludarabine-mediated activation of nuclear factor-κB signaling. Moreover, this combination impairs angiogenesis and CXCL12-induced responses in NOTCH1-mutated CLL cells, in particular those related to tumoral migration and invasion. Importantly, all these collaborative effects are specific for NOTCH1 mutation and do not occur in unmutated cases. In conclusion, we provide evidence that Notch is a therapeutic target in CLL cases with NOTCH1-activating mutations, supporting the use of Notch pathway inhibitors in combination with chemotherapy as a promising approach for the treatment of these high-risk CLL patients.

Neutrophil Gelatinase-Associated Lipocalin (NGAL), Pro-Matrix Metalloproteinase-9 (pro-MMP-9) and Their Complex Pro-MMP-9/NGAL in Leukaemias

Matrix metalloproteinase (MMP)-9 and neutrophil gelatinase-associated lipocalin (NGAL) have gained attention as cancer biomarkers. The inactive zymogen form of MMP-9 (pro-MMP-9) also exists as a disulphide-linked heterodimer bound to NGAL in humans. Leukaemias represent a heterogeneous group of neoplasms, which vary in their clinical behavior and pathophysiology. In this review, we summarize the current literature on the expression profiles of pro-MMP-9 and NGAL as prognostic factors in leukaemias. We also report the expression of the pro-MMP-9/NGAL complex in these diseases. We discuss the roles of (pro)-MMP-9 (active and latent forms) and NGAL in tumour development, and evaluate the mechanisms by which pro-MMP-9/NGAL may influence the actions of (pro)-MMP-9 and NGAL in cancer. Emerging knowledge about the coexpression and the biology of (pro)-MMP-9, NGAL and their complex in cancer including leukaemia may improve treatment outcomes.

Angiogenesis and hematological malignancies

Since the initial hypotheses on the importance of angiogenesis in the pathogenesis of cancer approximately 30 years ago, there have been major advances in the understanding of the cellular and molecular mechanisms involved in the regulation of this complex process of new vessel formation. Among the multitude of factors, vascular endothelial growth factor (VEGF) has emerged as one of the most potent angiogenic factors, being implicated in the initiation of signal transduction responsible for cell proliferation, survival, migration and adhesion. Inhibition of VEGF and its signaling pathway offers a potential new molecular target in cancer therapy. This article reviews the role of angiogenesis and its mediators, particularly vascular endothelial growth factors, in hematological malignancies, as well as the potential use of anti-angiogenic therapies in the management of these conditions.

Angiogenesis as a treatment target in leukemia

SUMMARY The importance of angiogenesis in the growth and survival of leukemia has been well established and confirmed by several studies. In the last 20 years, several antiangiogenic agents have been used in preclinical and clinical studies of the treatment of leukemia. This review article summarizes the literature focusing on the relationship between angiogenesis and disease progression, and the advantages and limits of the antiangiogenic treatment of leukemia.

Impaired immunomodulatory function of chronic myeloid leukemia cancer stem cells and the possible mechanism involved in it

BACKGROUND

Cancer stem cells (CSCs) are proposed to persist in tumors as a distinct population and cause relapse and metastasis by giving rise to new tumors. Development of specific therapies targeted at CSCs holds hope for the improvement of survival and quality of life of cancer patients, especially for sufferers of metastatic disease. This is particularly true in chronic myeloid leukemia (CML).

METHODS

In this study, we isolated fetal liver kinase-1-positive (Flk1(+)) cells carrying the BCR/ABL fusion gene from the bone marrow of Philadelphia chromosome-positive (Ph(+)) patients with stem cells property. We examined their biological characteristics as well as immunological function and further detected the possible molecular mechanism involved in the leukemia genesis.

RESULTS

We showed that CML patient-derived Flk1(+)CD31(-)CD34(-) MSCs had normal morphology, phenotype and karyotype but appeared impaired immunomodulatory function. The capacity of Flk1(+)CD31(-)CD34(-) MSCs from CML patients to inhibit T lymphocyte activation and proliferation was impaired in vitro. CML patient-derived MSCs have dampening immunomodulatory functions, suggesting that the dysregulation of hematopoiesis and immune response might originate from MSCs rather than HSCs. These Ph(+) putative CML hemangioblast upregulated TGF-β1 and resultantly activated matrix metalloproteinase-9 (MMP-9) to enhance s-KitL and s-ICAM-1 secretion, which activated c-kit(+) HSCs from the quiescent state to proliferative state. Further studies showed that phosphatidylinositol-3 kinase (PI3K)/Akt/nuclear factor (NF)-κB signaling pathway was involved in CML pathogenesis.

CONCLUSIONS

Flk1(+)CD31(-)CD34(-) MSCs that express BCR/ABL leukemia oncogene are CSCs of CML and they play a critical role in the progression of CML through PI3K/Akt/NF-κB/MMP-9/s-ICAM-1/s-KitL signaling pathway beyond HSCs.

Lenalidomide reduces survival of chronic lymphocytic leukemia cells in primary cocultures by altering the myeloid microenvironment

Lenalidomide treatment of primary CLL/nurse-like cell cocultures resulted in significantly decreased viability of CLL cells. Lenalidomide increased IL-10 levels, activation of STAT1, expression of ICAM-1, and migration-related genes, and reduced CLL cell motility.

Targeting chronic lymphocytic leukemia cells with a humanized monoclonal antibody specific for CD44

Chronic lymphocytic leukemia (CLL) cells express high levels of CD44, a cell-surface glycoprotein receptor for hyaluronic acid. We found that a humanized mAb specific for CD44 (RG7356) was directly cytotoxic for leukemia B cells, but had little effect on normal B cells. Moreover, RG7356 could induce CLL cells that expressed the zeta-associated protein of 70 kDa (ZAP-70) to undergo caspase-dependent apoptosis, independent of complement or cytotoxic effector cells. The cytotoxic effect of this mAb was not mitigated when the CLL cells were cocultured with mesenchymal stromal cells (MSCs) or hyaluronic acid or when they were stimulated via ligation of the B-cell receptor with anti-µ. RG7356 induced rapid internalization of CD44 on CLL cells at 37 °C, resulting in reduced expression of ZAP-70, which we found was complexed with CD44. Administration of this mAb at a concentration of 1 mg/kg to immune-deficient mice engrafted with human CLL cells resulted in complete clearance of engrafted leukemia cells. These studies indicate that this mAb might have therapeutic activity, particularly in patients with CLL that express ZAP-70.

Angiogenic factors in chronic lymphocytic leukemia

Angiogenesis is a complex process controlled by the balance of a large number of regulating factors, the pro- and anti-angiogenic factors. Dysregulation of angiogenesis occurs in various pathologies and is one of the hallmarks for cancer. Recent emphasis on the microenvironment's influence in chronic lymphocytic leukemia (CLL) progression and drug resistance nurtures the interest in angiogenesis. Researchers have already identified a variety of angiogenic factors involved in the CLL, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), angiopoietin-2(Ang-2), thrombospondin-1 (TSP-1), as well as extracellular proteinases such as matrix metalloproteinase-9 (MMP-9). Besides modulating neovascularization, angiogenic factors also participate in the regulation of pro-survival effects of CLL cells. However, the precise mechanism involved still needs to be elucidated further. At present, the levels of some angiogenic factors are regarded as prognostic markers of the progression of CLL, although it is not widely used. Several anti-VEGF agents are currently under clinical trial. Advances in the understanding of the bases of angiogenesis regulators will be benefit for the comprehension of CLL pathogenesis and help to conquer the disease.

A 17-residue sequence from the matrix metalloproteinase-9 (MMP-9) hemopexin domain binds α4β1 integrin and inhibits MMP-9-induced functions in chronic lymphocytic leukemia B cells

We previously showed that pro-matrix metalloproteinase-9 (proMMP-9) binds to B chronic lymphocytic leukemia (B-CLL) cells and contributes to B-CLL progression by regulating cell migration and survival. Induction of cell survival involves a non-proteolytic mechanism and the proMMP-9 hemopexin domain (PEX9). To help design specific inhibitors of proMMP-9-cell binding, we have now characterized B-CLL cell interaction with the isolated PEX9. B-CLL cells bound soluble and immobilized GST-PEX9, but not GST, and binding was mediated by α4β1 integrin. The ability to recognize PEX9 was observed in all 20 primary samples studied irrespective of their clinical stage or prognostic marker phenotype. By preparing truncated forms of GST-PEX9 containing structural blades B1B2 or B3B4, we have identified B3B4 as the primary α4β1 integrin-interacting region within PEX9. Overlapping synthetic peptides spanning B3B4 were then tested in functional assays. Peptide P3 (FPGVPLDTHDVFQYREKAYFC), a sequence present in B4 or smaller versions of this sequence (peptides P3a/P3b), inhibited B-CLL cell adhesion to GST-PEX9 or proMMP-9, with IC(50) values of 138 and 279 μm, respectively. Mutating the two aspartate residues to alanine rendered the peptides inactive. An anti-P3 antibody also inhibited adhesion to GST-PEX9 and proMMP-9. GST-PEX9, GST-B3B4, and P3/P3a/P3b peptides inhibited B-CLL cell transendothelial migration, whereas the mutated peptide did not. B-CLL cell incubation with GST-PEX9 induced intracellular survival signals, namely Lyn phosphorylation and Mcl-1 up-regulation, and this was also prevented by the P3 peptides. The P3 sequence may, therefore, constitute an excellent target to prevent proMMP-9 contribution to B-CLL pathogenesis.

Concentration kinetics of serum MMP-9 and TIMP-1 after blunt multiple injuries in the early posttraumatic period

Metalloproteinases are secreted in response to a variety of inflammatory mediators and inhibited by tissue inhibitors of matrixmetalloproteinases (TIMPs). Two members of these families, MMP-9 and TIMP-1, were differentially expressed depending on clinical parameters in a previous genomewide mRNA analysis. The aim of this paper was now to evaluate the posttraumatic serum levels and the time course of both proteins depending on distinct clinical parameters. 60 multiple traumatized patients (ISS > 16) were included. Blood samples were drawn on admission and 6 h, 12 h, 24 h, 48 h, and 72 h after trauma. Serum levels were quantified by ELISA. MMP-9 levels significantly decreased in the early posttraumatic period (P < 0.05) whereas TIMP-1 levels significantly increased in all patients (P < 0.05). MMP-9 and TIMP-1 serum concentration kinetics became manifest in an inversely proportional balance. Furthermore, MMP-9 presented a stronger decrease in patients with severe trauma and non-survivors in contrast to minor traumatized patients (ISS ≤ 33) and survivors, initially after trauma.

Evidence for a macromolecular complex in poor prognosis CLL that contains CD38, CD49d, CD44 and MMP-9

Progressive chronic lymphocytic leukaemia is characterized by the accumulation of neoplastic B-cells in the tissues and correlates with the expression of prognostic biomarkers, such as CD38, CD49d and matrix metalloproteinase-9 (MMP9), which are involved in migration and tissue invasion. In this study we investigated the physical relationship between these molecules and demonstrated that CD38, CD49d, MMP9 and CD44 were physically associated in a supramolecular cell surface complex. Our findings provide a molecular basis for the correlation between expression of these proteins and prognosis and, as the complex is not present in normal B-cells, suggest a novel leukaemia-specific therapeutic target.

The research on the immuno-modulatory defect of mesenchymal stem cell from Chronic Myeloid Leukemia patients

Overwhelming evidence from leukemia research has shown that the clonal population of neoplastic cells exhibits marked heterogeneity with respect to proliferation and differentiation. There are rare stem cells within the leukemic population that possess extensive proliferation and self-renewal capacity not found in the majority of the leukemic cells. These leukemic stem cells are necessary and sufficient to maintain the leukemia. While the hematopoietic stem cell (HSC) origin of CML was first suggested over 30 years ago, recently CML-initiating cells beyond HSCs are also being investigated. We have previously isolated fetal liver kinase-1-positive (Flk1⁺) cells carrying the BCR/ABL fusion gene from the bone marrow of Philadelphia chromosome-positive (Ph⁺) patients with hemangioblast property. Here, we showed that CML patient-derived Flk1⁺CD31^-CD34^-MSCs had normal morphology, phenotype and karyotype but appeared impaired in immuno-modulatory function. The capacity of patient Flk1⁺CD31^-CD34^- MSCs to inhibit T lymphocyte activation and proliferation was impaired in vitro. CML patient-derived MSCs have impaired immuno-modulatory functions, suggesting that the dysregulation of hematopoiesis and immune response may originate from MSCs rather than HSCs. MSCs might be a potential target for developing efficacious cures for CML.

NAD+-metabolizing ecto-enzymes shape tumor-host interactions: the chronic lymphocytic leukemia model

Nicotinamide adenine dinucleotide (NAD(+)) is an essential co-enzyme that can be released in the extracellular milieu. Here, it may elicit signals through binding purinergic receptors. Alternatively, NAD(+) may be dismantled to adenosine, up-taken by cells and transformed to reconstitute the intracellular nucleotide pool. An articulated ecto-enzyme network is responsible for the nucleotide-nucleoside conversion. CD38 is the main mammalian enzyme that hydrolyzes NAD(+), generating Ca(2+)-active metabolites. Evidence suggests that this extracellular network may be altered or used by tumor cells to (i) nestle in protected areas, and (ii) evade the immune response. We have exploited chronic lymphocytic leukemia as a model to test the role of the ecto-enzyme network, starting by analyzing the individual elements that make up the whole picture.

Matrix metalloproteinase-9 promotes chronic lymphocytic leukemia b cell survival through its hemopexin domain

Matrix metalloproteinase-9 (MMP-9) is the major MMP produced by B-CLL cells and contributes to their tissue infiltration by degrading extracellular and membrane-anchored substrates. Here we describe a different function for MMP-9 in B-CLL, which involves the hemopexin domain rather than its catalytic function. Binding of soluble or immobilized (pro)MMP-9, a catalytically inactive proMMP-9 mutant, or the MMP-9 hemopexin domain to its docking receptors alpha4beta1 integrin and CD44v, induces an intracellular signaling pathway that prevents B-CLL apoptosis. This pathway is induced in all B-CLL cases, is active in B-CLL lymphoid tissues, and consists of Lyn activation, STAT3 phosphorylation, and Mcl-1 upregulation. Our results establish that MMP/receptor binding induces intracellular survival signals and highlight the role of (pro)MMP-9 in B-CLL pathogenesis.

A basal-cell-like compartment in head and neck squamous cell carcinomas represents the invasive front of the tumor and is expressing MMP-9

Head and neck squamous cell carcinomas (HNSCCs) are the most frequent malignancies of the upper aerodigestive tract. The cancer stem cell (CSC) hypothesis concludes that CSCs constitute the dangerous tumor cell population due to their ability of self-renewal and being associated with relapse of tumor disease, invasiveness and resistance to chemo(radio)therapy. The aim of this study was to look for CSC candidates and expression of MMP-9 that previously was implicated in HNSCC invasiveness. Immunohistochemical, immunofluorescence and Western blot analysis were performed on HNSCC tumor specimens using antibodies specific for MMP-9, CD44, ALDH1 and CK14. Gelatinolytic activity was assessed by zymography. Pearson correlation analysis was used for statistical comparison. Immunohistochemical analysis found CD44 and MMP-9 to co-localize in tumor cells at the invasive front. Western blot analysis demonstrated a significant correlation (p=0.0047) between CD44 and MMP-9 in the tested tissues. In addition gelatinolytic activity of HNSCC tissues was found to significantly correlate (p=0.0010) with MMP-9 expression. The CD44(+) invasive front of the tumor was also positive for ALDH1 and CK14, all of them being typically expressed by cells in the basal cell layer of normal stratified squamous epithelia that also harbors the epithelial stem cells. The observations point to a role of a MMP-9 positive basal-cell-like cell layer in the process of HNSCC invasiveness. This compartment likely contains CSCs since it is expressing the putative CSC markers CD44, ALDH1 and CK14. This cell layer therefore should be considered a major therapeutic target in the treatment of head and neck cancer.

VEGF/VEGFR2 interaction down-regulates matrix metalloproteinase-9 via STAT1 activation and inhibits B chronic lymphocytic leukemia cell migration

B-cell chronic lymphocytic leukemia (B-CLL) migration involves several molecules, including matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF). We have studied whether VEGF regulates MMP-9. VEGF significantly reduced MMP-9 protein expression in a dose-dependent manner, measured by gelatin zymography. Blocking the VEGFR2 receptor restored MMP-9 levels, implicating this receptor in the observed effect. Down-regulation of MMP-9 by VEGF resulted in significant inhibition of B-CLL cell migration through Matrigel or human umbilical vein endothelial cells, confirming the crucial role of MMP-9 in these processes. Reverse-transcription polymerase chain reaction analyses revealed that VEGF regulated MMP-9 at the transcriptional level. Indeed, VEGF induced STAT1 tyrosine phosphorylation, and this was blocked by inhibiting VEGFR2. STAT1 was responsible for MMP-9 down-regulation, as STAT1 gene silencing restored MMP-9 production and B-CLL cell migration in the presence of VEGF. Thus, the levels of VEGF and MMP-9 influence B-CLL cell expansion and both molecules could constitute therapeutic targets for this disease.

Serum levels of matrix metalloproteinase-2 and -9 and conventional tumor markers (CEA and CA 19-9) in patients with colorectal and gastric cancers

BACKGROUND

Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9, play an important role in tumor invasion and metastasis. This study aimed to determine the serum levels of MMP-2, MMP-9, 130- and 225-kDa gelatinolytic bands and conventional tumor markers, carcinoembryonic antigen (CEA) and cancer antigen (CA) 19-9, in patients with gastrointestinal cancers. The relationship between these parameters and clinicopathological factors was also studied.

METHODS

Sera from controls (n=19), and patients with colorectal (n=47) and gastric (n=34) cancer were collected prospectively. The gelatinolytic activities of MMP-2, MMP-9, 130- and 225-kDa bands were determined using gelatin zymography. CEA and CA 19-9 were determined using immunoradiometric assay (IRMA).

RESULTS

Serum levels of MMP-9, 130- and 225-kDa gelatinolytic bands, CEA, and CA 19-9, but not MMP-2, in colorectal and gastric cancer were significantly higher than that of controls. No significant correlation was found between histological grade or clinical stage and levels of MMP-9, 130- and 225-kDa gelatinolytic bands, which were correlated (r=0.61-0.89, p<0.005).

CONCLUSIONS

Our findings suggest that zymographic determination of MMP-9, 130- and 225-kDa gelatinolytic bands in colorectal and gastric cancer may be useful in studying these types of cancer in parallel with conventional tumor markers.

TIMP-1 binding to proMMP-9/CD44 complex localized at the cell surface promotes erythroid cell survival

Besides its ability to inhibit MMP activity, TIMP-1 exhibits other biological functions. We earlier reported that TIMP-1 induced UT-7 erythroid cell survival through activation of the JAK2/PI 3-kinase/Akt pathway and we now aim to determine whether the TIMP-1 anti-apoptotic effect requires MMP involvement. We first show that proMMP-9 was expressed in UT-7 cells and associated with the cell plasma membrane. Such proMMP-9 localization was crucial for TIMP-1 intracellular signalling since (i) TIMP-1 specifically bound to proMMP-9 and (ii) proMMP-9 silencing abrogated the TIMP-1 effect. We also demonstrated that TIMP-1 anti-apoptotic effect was independent on MMP inhibition since MMP-9 function blocking antibodies as well as a synthetic MMP inhibitor were unable to reproduce TIMP-1 effect. Nevertheless, these compounds prevented TIMP-1 binding to proMMP-9 and subsequently abolished TIMP-1-induced cell survival. We finally demonstrated that CD44 anchored proMMP-9 to the plasma membrane and enabled TIMP-1-mediated signal transduction. Therefore, our results indicate that the anti-apoptotic signalling of TIMP-1 depends on the formation of a ternary complex between TIMP-1, proMMP-9 and CD44 at the UT-7 erythroid cell surface.

Alpha4beta1 integrin and 190-kDa CD44v constitute a cell surface docking complex for gelatinase B/MMP-9 in chronic leukemic but not in normal B cells

As B-cell chronic lymphocytic leukemia (B-CLL) progresses, malignant cells extravasate and infiltrate lymphoid tissues. Several molecules, including gelatinase B/MMP-9, contribute to these processes. Although mainly a secreted protease, some MMP-9 is present at the B-CLL cell surface and the function, mode of anchoring, and interactions of this MMP-9 are unknown. Here we show that anti-MMP-9 antibodies immunoprecipitated a 190-kDa CD44v isoform and alpha4beta1 integrin from B-CLL cells, but not from normal B cells. Function-blocking antibodies to alpha4beta1 or CD44, or transfection with specific siRNAs, decreased cell-associated proMMP-9 and increased the secreted form. B-CLL cells attached to and bound proMMP-9 and active MMP-9, and this was inhibited by blocking the expression or function of alpha4beta1 or CD44. The MMP-9 hemopexin domain was critical in these interactions. alpha4beta1 and 190-kDa CD44v (but not CD44H) formed a complex at the cell surface, since they both coimmunoprecipitated with anti-alpha4, anti-beta1, or anti-CD44 antibodies. Immunofluorescence analyses confirmed that alpha4beta1 and CD44v colocalized with MMP-9. Binding of proMMP-9 inhibited B-CLL cell migration, and this required MMP-9 proteolytic activity. Thus, we have identified alpha4beta1 and CD44v as a novel proMMP-9 cell surface docking complex and show that cell-associated MMP-9 may regulate B-CLL cell migration and arrest.