Regulation of gelatinase B (MMP-9) in leukocytes by plant lectins

New Lectins from Mediterranean Flora. Activity against HT29 Colon Cancer Cells

Experiments conducted in vitro and in vivo, as well as some preclinical trials for cancer therapeutics, support the antineoplastic properties of lectins. A screening of antitumoral activity on HT29 colon cancer cells, based on polypeptide characterization and specific lectin binding to HT29 cells membrane receptors, was performed in order to assess the bioactivities present in four Mediterranean plant species: Juniperus oxycedrus subsp. oxycedrus, Juniperus oxycedrus subsp. badia, Arbutus unedo and Corema album. Total leaf proteins from each species were evaluated with respect to cell viability and inhibitory activities on HT29 cells (cell migration, matrix metalloproteinase –MMP proteolytic activities). A discussion is presented on a possible mechanism justifying the specific binding of lectins to HT29 cell receptors. All species revealed the presence of proteins with affinity to HT29 cell glycosylated receptors, possibly explaining the differential antitumor activity exhibited by the two most promising species, Juniperus oxycedrus subsp. badia and Arbutus unedo.

A study to investigate the biological activity of proteoglycan mixture extract from Convolvulus arvensis

BACKGROUND

Convolvulus arvensis L. (Convolvulaceae), bindweeds, is inhabitant to Iran and its proteoglycan mixture (PGM) has been reported to possess different biological activities. In the present study, we aimed to investigate different properties of PGM including anti-tumor, anti-angiogenesis and immunostimulatory activities.

METHODS

PGM was prepared from the roots of C. arvensis. Various cancer cell lines were treated with PGM and the cytotoxicity was assessed after 24 h of incubation using MTT assay. In addition, J774A.1 macrophages were stimulated with LPS (1 µg/mL) and then with PGM. Then, production of nitric oxide (NO) as a marker of inflammation was measured using Griess reagent. Moreover, PGM was subjected to cultivated Leishmania major promastigotes and leishmanicidal activity was determined using MTT assay. More importantly, human umbilical vein endothelial cells (HUVEC) cultured on matrigel basement matrix and tube formation after treatment with PGM was considered microscopically for the determination of angiogenesis.

RESULTS

Obtained results revealed that PGM significantly inhibited the formation of vascular-like tubes by HUVECs without any effect on their viability. Furthermore, PGM significantly exhibited leishmanicidal activity by the mechanism of suppressing L. major promastigotes developmental growth in vitro. However, PGM was shown to have no effect on the growth of cancer cells and production of NO by LPS-stimulated macrophages.

CONCLUSIONS

The present study provides some new evidence on remarkable leishmanicidal and anti-angiogenic activities of PGM. These findings also afford the scientific basis for the use of C. arvensis as a candidate medicinal plant for further thoroughly phytochemical investigations toward discovering leishmanicidal and anti-angiogenic compounds.

A novel antimicrobial lectin from Eugenia malaccensis that stimulates cutaneous healing in mice model

OBJECTIVE

The present work reports the purification and partial characterization of an antibacterial lectin (EmaL) obtained from Eugenia malaccensis seeds as well as the evaluation of its effect in the daily topical treatment of repairing process of cutaneous wounds in mice.

MATERIALS AND METHODS

The cutaneous wound was produced by the incision of the skin and use of lectin in the treatment of mice cutaneous wounds was evaluated. Surgical wounds were treated daily with a topical administration of EmaL and parameters such as edema, hyperemia, scab, granulation and scar tissues as well as contraction of wounds were analyzed.

RESULTS

A novel lectin, with a molecular mass of 14 kDa, was isolated from E. malaccensis using affinity chromatography. The lectin (EmaL) agglutinated glutaraldehyde-treated rabbit and human erythrocytes; the lectin-induced rabbit erythrocyte agglutination was inhibited by glucose, casein, ovalbumin and fetuin. Also, Emal was very effective in the inhibition of bacterial growth, with the best inhibition results obtained for Staphylococcus aureus. Inflammatory signals such as edema and hyperemia were statistically less intense when EmaL was applied compared to the control. The histopathological analysis showed that the treated injured tissue presented reepithelialization (complete or partial) and areas of transition more evidenced than those of the control group, especially due to well organized pattern of collagen fibers presented in the granulation fibrous tissue.

CONCLUSION

Presented results are a preliminary indication of the pharmacological interest in using EmaL as antimicrobial agent and in the repairing process of cutaneous wounds.

Asialoglycoprotein receptor promotes cancer metastasis by activating the EGFR-ERK pathway

Although the importance of glycans in malignant cell behavior is well documented, the potential involvement of endogenous lectins as modifiers of progression and metastasis in the tumor microenvironment has not been explored. In this study, we show that loss of the hepatic asialoglycoprotein receptor (ASGPR) in mice severely reduces the frequency of spontaneous lung metastasis after intrahepatic implantation of murine Lewis lung carcinoma (3LL) cells. Conversely, in vitro treatment with recombinant ASGPR increased the invasive and metastatic capacity of 3LL cells before intrahepatic implantation. ASGPR treatment in vitro increased the expression and production of matrix metalloproteinase-9 through activation of the epidermal growth factor receptor-extracellular signal-regulated kinase (EGFR-ERK) pathway. Our findings identify ASGPR as a novel important factor that responds to endogenous lectins in the tumor microenvironment to promote cancer metastasis by activating the EGFR-ERK pathway through interactions with counter-receptors on cancer cells.

Early Upregulation of Matrix Metalloproteinases Following Reperfusion Triggers Neuroinflammatory Mediators in Brain Ischemia in Rat

Abnormal expression of matrix metalloproteinases (MMPs) has been implicated in the pathophysiology of neuroinflammatory processes that accompany most central nervous system disease. In particular, early upregulation of the gelatinases MMP-2 and MMP-9 has been shown to contribute to disruption of the blood-brain barrier and to death of neurons in ischemic stroke. In situ zymography reveals a significant increase in gelatinolytic MMPs activity in the ischemic brain hemisphere after 2-h middle cerebral artery occlusion (MCAo) followed by 2-h reperfusion in rat. Accordingly, gel zymography demonstrates that expression and activity of MMP-2 and MMP-9 are enhanced in cortex and striatum ipsilateral to the ischemic insult. The latter effect appears to be instrumental for development of delayed brain damage since administration of a broad spectrum, highly specific MMPs inhibitor, GM6001, but not by its negative control, results in a significant (50%) reduction in ischemic brain volume. Increased gelatinase activity in the ischemic cortex coincides with elevation (166% vs sham) of mature interleukin-1beta (IL-1beta) after 2-h reperfusion and this does not appear to implicate a caspase-1-dependent processing of pro(31kDa)-IL-1beta to yield mature (17kDa) IL-1beta. More importantly, when administered at a neuroprotective dose GM6001 abolishes the early IL-1beta increase in the ischemic cortex and reduces the cleavage of the cytokine proform supporting the deduction that MMPs may initiate IL-1beta processing. In conclusion, development of tissue damage that follows transient ischemia implicates a crucial interplay between MMPs and mediators of neuroinflammation (e.g., IL-1beta), and this further underscores the therapeutic potential of MMPs inhibitors in the treatment of stroke.

Altered plasma matrix metalloproteinase-9/tissue metalloproteinase-1 concentration during the early postoperative period in patients with colorectal cancer

BACKGROUND

The authors have previously demonstrated that insulin-like growth factor binding protein-3 (IGFBP-3) is depleted in plasma for 1 to 3 days after major open surgery (OS), but not after laparoscopic surgery (LS). After surgery, IGFP-3 cleavage occurs rapidly and is likely attributable to altered plasma proteolytic activity. This study aimed to assess plasma proteolysis after both open and closed colorectal resection and, if possible, to identify a protease/protease inhibitor system affected by surgery.

METHODS

Plasma from 88 patients with colorectal cancer (stages I-III) who underwent resection was obtained preoperatively (pre-OP) and on postoperative days (POD) 1 to 3. Plasma proteolytic activity was assessed via zymography. On the basis of the results, specific protease and protease inhibitor concentrations were next measured via enzyme-linked immunoassay (ELISA). Statistical analysis was performed using Wilcoxon's test.

RESULTS

Early after surgery, zymography showed a predominant band representing a 92-kDa gelatinase corresponding to a proform of matrix metalloproteinase-9 (MMP-9), a protease known to cleave IGFBP-3. In OS patients, the mean concentration of plasma MMP-9 was significantly higher on POD 1 than at pre-OP (p < 0.003). On POD 2 and 3, no differences were noted. In the LS group, the mean levels of MMP-9 before and after surgery were comparable. The levels of a natural MMP-9 inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), also were measured. In the OS group, the level of TIMP-1 was significantly higher on POD 1 (p < 0.0003) and POD 2 (p < 0.01) and 3 (p < 0.01) than at pre-OP. In the LS group, a smaller but significant increase in TIMP-1 levels was found between the pre-OP sample and the POD 1 (p < 0.01) and POD 2 (p < 0.01) samples. No difference was noted on POD 3 (p = 0.1).

CONCLUSIONS

Open surgery, but not laparoscopic surgery, is accompanied by a short-lived significant increase in MMP-9 levels, which likely accounts for the decrease in IGFBP-3 levels observed after OS. The transitory nature of MMP-9 imbalance may be attributable to the increase in TIMP-1 levels postoperatively.

Gelatinase B and TIMP-1 are regulated in a cell- and time-dependent manner in association with neuronal death and glial reactivity after global forebrain ischemia

Matrix metalloproteinases (MMPs) belong to a large family of endopeptidases that regulate the pericellular environment through the cleavage of protein components of the extracellular matrix, membrane receptors and cytokines. MMP activity is controlled by the multifunctional tissue inhibitors of metalloproteinases (TIMPs). Proteases and their inhibitors are critically involved in developmental and pathological processes in numerous organs, including the brain. Global transient cerebral ischemia induces selective delayed neuronal death and neuroinflammation. We compared, in discrete vulnerable and resistant areas of the ischemic rat hippocampus, the kinetics and cellular distribution of gelatinase B and its principal inhibitor TIMP-1 and we assessed by in situ zymography, the net gelatinolytic activity at the cellular level. We show that gelatinases are expressed and active in neurons, suggesting that MMPs play a role in maintaining neural homeostasis. In the ischemic rat brain, expression and activity of gelatinase B, and expression of TIMP-1 are altered in a time-, region- and cell-dependent manner. Gelatinase B is induced first in reactive microglia and subsequently in reactive astrocytes. In situ, increases in gelatinase activity accompanied the progression of neuronal death and glial reactivity. Our results suggest that MMPs and TIMPs are involved in cell viability and tissue remodelling in the ischemic brain, and reinforces the idea that the MMP/TIMP system contributes both to neuronal demise and tissue repair in the context of glial reactivity.

Expression and activation of pro-MMP-2 and pro-MMP-9 during rat liver regeneration

Partial hepatectomy triggers a variety of biological phenomena, which culminate in regeneration of the liver mass. Hepatocyte proliferation is a major feature of the regenerating liver after partial hepatectomy. Previous studies in our laboratory suggested that hepatic matrix remodeling might be a prerequisite process for hepatocyte proliferation in the regenerating liver. In the present study we use immunohistochemical staining, Western blot analysis, and gelatin zymography to show that the inactive matrix metalloproteinases (MMPs), pro-MMP-2 and pro-MMP-9, are elevated at 30 minutes and activated at 6 to 12 hours and at 3 to 6 hours, respectively, after hepatectomy. Sham-operated livers did not show an increase in inactive pro-MMP-2 and pro-MMP-9 and did not contain active MMP-2 or MMP-9. To examine whether tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) is changed to regulate the activities of MMPs after partial hepatectomy, the level of TIMP-1 protein was analyzed by both immunohistochemistry and Western blot analysis. The level of TIMP-1 protein appears to increase by 6 to 18 hours, implying that an increase in TIMP-1 regulates activities of active MMP-2 and MMP-9. Taken together, these results suggest that hepatic matrix remodeling is mediated by activated MMPs, which contribute to modulation of the environment surrounding hepatocytes during rat liver regeneration.

Regulation of gelatinases in microglia and astrocyte cell cultures by plant lectins

The effects of 25 recently discovered plant lectins on cell proliferation and enzyme release were compared to those of previously known lectins on rat microglia and astrocyte cell cultures. A dose-dependent proliferation of microglial cells, but not of astrocytes, was induced by seven lectins, whereas five lectins showed dose-dependent cytotoxicity on both microglia and astrocyte cell cultures. The activity of gelatinase B (MMP-9) was strongly increased in microglial cells by the aforementioned seven lectins, by concanavalin A, and by phytohemagglutinin (PHA-E4), whereas gelatinase A (MMP-2) remained at constitutive levels. The five cytotoxic lectins decreased the activity of gelatinase B in microglia and of gelatinase A in astrocytes, in a dose-dependent manner. The lectin wheat germ agglutinin induced a decrease in gelatinase B activity in microglia, but stimulated gelatinase A and B activity in astrocytes. These results indicate that lectins possess neuromodulatory effects that may motivate the study of their effects on central nervous system (CNS) function in vivo. This, in turn, may lead to better insight into whether lectin or lectin-like molecules can interact with glial cells, and whether they have a role in acute toxicity and in multifactorial diseases in which environmental factors may play a role.

Characterization and molecular cloning of the lectin from Helianthus tuberosus

A lectin called Helianthus tuberosus agglutinin or Heltuba has been isolated from tubers of the Jerusalem artichoke, a typical representative of the Asteraceae family. Heltuba is a tetrameric protein composed of four identical subunits of 15.5 kDa and exhibits a preferential specificity towards oligomannosides. Cloning of the corresponding cDNAs revealed that the mature lectin polypeptide comprises the entire open reading frame of the cDNA suggesting that the primary translation product is not processed and that the lectin is a cytosolic protein. Searches in the databases revealed sequence similarity with lectins from the taxonomically unrelated Convolvulaceae and Moraceae species. Therefore, the discovery of Heltuba is of great importance in view of the occurrence and molecular evolution of the jacalin-related lectins.