Reduction of in vivo tumor growth by MMI-166, a selective matrix metalloproteinase inhibitor, through inhibition of tumor angiogenesis in squamous cell carcinoma cell lines of head and neck

MMI-166, a selective matrix metalloproteinase inhibitor, promotes apoptosis in human pancreatic cancer

MMI-166 is a third-generation selective matrix metalloproteinase (MMP) inhibitor that prevents tumor invasion and metastasis by downregulating the activity of MMP-2 and MMP-9. However, MMI-166's effect in pancreatic cancer cells has not been widely studied. Initially, we treated SW1990, human pancreatic cancer cells, with 0, 50 or 100 μg/ml of MMI-166 for 24 h. Apoptosis in the cells was then observed by inverted fluorescence microscope and flow cytometry; the apoptosis rate was dependent on MMI-166 concentration. We then injected nude mice with SW1990 cells. Volume of the resulting xenograft tumors in nude mice treated with MMI-166 was far less than that of the control group, whereas their apoptotic index was much greater. Expression of MMP-2, MMP-9, c-myc and survivin were markedly lower in tumors from the treated mice than in the control group. In cell experiments, MMP-2 and MMP-9 activities were downregulated by MMI-166 compared with controls, as were both mRNA and protein levels of MMP-2, MMP-9 and c-myc, although survivin expression did not differ. These results show that MMI-166 can induce apoptosis of pancreatic cancer cells in vitro and in vivo. The mechanism may be related to downregulation of c-myc by MMI-166.

Recent advances in oral anticancer agents for colon cancer

To provide therapeutic alternatives to intravenous colon chemotherapy major recent research is focusing on the development of oral chemotherapeutic agents with the intention to improve the quality of life of patients. Initially 5-fluorouracil was most commonly used for the treatment of colorectal cancer but currently oxaliplatin and irinotecan are also available. The majority of these new drugs are pyrimidines and their analogs. The rationale for using oral anticancer agents is discussed and new drugs, such as farnesyl protein transferase inhibitor S-1, rubitecan, ZD9331, MMI-166, eflornithine, sulindac, and oral camptothecin analogs, among others, are presented with the results of their preclinical and clinical developments. This article focuses on the advancement of clinical development and also discusses the relative merits and demerits of these agents. The accelerated approval of these agents by regulatory authorities is supported by survival benefit, response rate and time to progression.

Tumor dormancy and the neuroendocrine system: an undisclosed connection?

Tumor dormancy is a poorly understood phenomenon conceptualized as a protracted quiescent state during which cancer cells are present but clinical disease is not apparent, a condition referred to as "cancer without disease" by Folkman. Examples include the incidental detection of occult in situ tumors in post-mortem organ analysis and cancer recurrence after long disease-free periods. Lack of angiogenic competency has been proposed as a major determinant of the fate of dormant tumors. Other proposed processes include establishment of homeostatic equilibrium between tumor cells and the host's immune system response and a non-permissive microenvironment for tumor growth. Recent cellular and molecular studies suggest that neuroendocrine mediators regulate the biology of tumor progression and act as endogenous modulators of angiogenesis, inflammation, and other molecular processes involved in tumor reactivation from dormancy. We review experimental and clinical evidence and propose that neuroendocrine dynamics of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis might contribute to the loss of tumor dormancy.

Tissue inhibitor of metalloproteinases in oral squamous cell carcinomas - a therapeutic target?

Matrix metalloproteinases (MMPs) are proteases responsible for remodeling the extracellular matrix (ECM) and enabling spreading and metastasis of tumor cells, a common phenomenon in oral squamous cell carcinomas (OSCC). They are strongly blocked by several inhibitors, among which we must highlight, for their specificity and potency, the endogenous tissue inhibitors of metalloproteinases (TIMP-1, -2, -3 and -4). The goal of this paper is to describe the expression of TIMPs in OSCC, determining their relation with clinical, histological and prognostic factors, delving into OSCC regulation mechanisms and discussing the use of exogenous TIMPs to treat this type of tumors. Expression of TIMPs in OSCC is higher in tumors than in normal tissue, which correlates with an increase of metastatic risk and regional lymph node affectation. Although some metalloproteinases inhibitors (MMIs) have shown promising results in the treatment of these tumors, their use in OSCC has not been widely tested; and although some indirect MMIs, like COX-2 inhibitors, flavonoids and endostatin seem to have beneficial effects on the invasive capacity of OSCC through regulation of MMPs and TIMP levels, routine clinical use has not been accepted yet.

Restoration of BRAK / CXCL14 gene expression by gefitinib is associated with antitumor efficacy of the drug in head and neck squamous cell carcinoma

Clinical efficacy of gefitinib (ZD1839, Iressa), which is an inhibitor specific for epidermal growth factor (EGF) receptor tyrosine kinase, has been shown in non-small-cell lung carcinoma patients with EGF receptor mutations, so these mutations are useful marker(s) to find a responder for the drug. Recent studies have shown that the EGF receptor gene mutation is rare in squamous cell carcinoma in the esophageal and head and neck regions. We previously reported that the expression of the chemokine BRAK/CXCL14 in head and neck squamous cell carcinoma (HNSCC) cells was down-regulated by EGF treatment, and that forced expression of BRAK in tumor cells decreased the tumorigenicity of the cells in xenografts. Thus, we investigated the relationship between restoration of BRAK expression by gefitinib and the efficacy of the drug for tumor suppression. We found that EGF down-regulated BRAK expression through the MEK-extracellular signal regulated kinase pathway and that this down-regulated expression was restored by gefitinib in vitro. Oral administration of gefitinib significantly (P < 0.001) reduced tumor growth of xenografts of three HNSCC cell lines (HSC-2, HSC-3, and HSC-4), in female athymic nude mice, accompanied by an increase in BRAK expression specifically in tumor tissue. This tumor-suppressing effect of the drug was not observed in the case of BRAK non-expressing cells. Furthermore introduction of BRAK shRNA vector reduced both the expression levels of BRAK in HSC-3 cells and the antitumor efficacy of gefitinib in vivo. Our data showing an inverse relationship between BRAK expression levels in tumor cells and the tumor growth rate indicate that the gefitinib-induced increase in BRAK expression is beneficial for tumor suppression in vivo.

Targeting angiogenesis in head and neck cancer

Tumor angiogenesis is a hallmark of advanced cancers and an attractive treatment target in multiple solid tumors. In the past 5 years anti-angiogenic therapies have seen a rapid ascent into mainstream clinical practice. For head and neck cancer (HNC), definitive evidence in the form of a pivotal trial is still pending. Nevertheless, preclinical and early clinical data support a central role of angiogenesis for HNC: up to 90% of HNCs express angiogenic factors such as vascular endothelial growth factor (VEGF) and the respective receptors (VEGFR1-3), and multiple studies support the prognostic implications of angiogenic markers for this tumor. Contrary to concerns that anti-angiogenic therapies could increase hypoxia and thereby treatment resistance, anti-angiogenic therapies in preclinical models appear to overcome resistance and preclinically synergize with traditional therapies, eg, radiation. Clinical use of anti-angiogenic agents for HNC, including bevacizumab, sorafenib, sunitinib, and others, is currently limited to clinical trials, and several larger trials are still ongoing. Single-agent anti-angiogenic drugs so far have not shown activity in unselected HNC patients, with a response rate of less than 4% for the small molecule anti-angiogenics sorafenib and the investigational agent SU5416. On the other hand, combinations of anti-angiogenic drugs with other treatments (analogous to other solid tumors) appear promising; for example, the combination of bevacizumab with the EGFR inhibitor erlotinib showed a response rate of 14.6%. Studies of bevacizumab with chemotherapy (phase III Eastern Cooperative Oncology Group [ECOG] trial) and in combination with chemoradiation are currently ongoing. The side effect profile is comparable to what has been observed in other tumor types and include hypertension, proteinuria, and thrombotic and hemorrhagic events. With the intense research effort preclinically and clinically, and some encouraging early results, anti-angiogenic therapies and biomarkers appear to be poised to play an important role in the treatment of HNC in the near future.

Role of metalloproteins in the clinical management of head and neck squamous cell carcinoma

Metalloproteins are a group of catalytic proteins, which play significant roles in cell cycle and death. Matrix metalloproteinases (MMPs) are a family of endopeptidases that are capable of digesting extracellular matrix components. They have been implicated in carcinogenesis and recent developments have been made to use MMPs clinically to predict outcomes. In the future, selective inhibition of these proteins and their regulatory pathways may prove useful in anticancer therapeutics. We present a review article on the clinical applications of metalloproteins in head and neck squamous cell carcinoma (HNSCC). Metalopanstimulin is highlighted as a putative metalloprotein of interest for those treating HNSCC. Expression of particular metalloproteins has correlation with lymph node metastasis, tumor invasiveness, and overall prognosis in HNSCC.

Extracellular matrix regulation of drug resistance in small-cell lung cancer

PURPOSE

Lung cancer is the leading cause of cancer deaths in the developed world. Small cell lung cancer (SCLC) has the worst prognosis due to the emergence of resistance to chemotherapy. This article will review recent work that has defined mechanisms of chemo-resistance focusing on the role of integrins.

RESULTS

SCLC is surrounded by an extensive stroma of extracellular matrix (ECM) and high levels of expression correlate with poor prognosis. ECM protects SCLC cells against chemotherapy-induced cell death by activating beta1 integrins leading to activation of phosphoinositide-3-OH kinase (PI3-kinase), which prevents etoposide-induced caspase-3 activation and subsequent apoptosis. Engagement of ECM prevents etoposide and radiation induced G2/M cell cycle arrest in SCLC cells by blocking the up-regulation of p21Cip1/WAF1 and p27Kip1 and the down-regulation of cyclins E, A and B. These effects are abrogated by pharmacological and genetic inhibition of PI3-kinase signalling.

CONCLUSIONS

Thus, ECM via beta1 integrin-mediated PI3-kinase activation allows SCLC cells to survive treatment induced cell cycle arrest and apoptosis with persistent DNA damage, providing a model to account for the emergence of acquired drug resistance. Novel therapeutic strategies may therefore be directed at inhibiting integrin-mediated cell survival signals improving response rates and cure in this devastating cancer.

Low-dose Methotrexate Inhibits Lung Metastasis and Lengthens Survival in Rat Osteosarcoma

Lung metastasis is the most crucial event affecting the treatment of osteosarcoma and is dependent on tumor angiogenesis. To improve the prognosis for patients with osteosarcoma, prevention of lung metastasis is essential. Low-dose methotrexate is a useful drug for treating a variety of diseases. Low-dose methotrexate reportedly plays a role in antiangiogenesis for the synovial blood vessels in rheumatoid arthritis. However, whether low-dose methotrexate is correlated with tumor angiogenesis and metastasis is unclear. We investigated the inhibitory effect of methotrexate on lung metastasis in a rat osteosarcoma cell line with high metastatic potential, S-SLM. Two weeks after inoculation of S-SLM cells into male Fischer 344 rats, low-dose methotrexate (1.2 mg/kg once or twice a week) or saline was intraperitonealy injected for 4 weeks and the antimetastatic effect was evaluated. Low-dose methotrexate significantly reduced the number of lung metastatic nodules and the wet weight of the lungs. Immunohistochemical staining showed a decrease in microvessel density in the metastatic nodules. We also evaluated the effect of methotrexate on the proliferation of endothelial cells and S-SLM osteosarcoma cells in vitro. Methotrexate significantly inhibited the proliferation of endothelial cells at a lower concentration than that of S-SLM osteosarcoma cells. These data suggest that low-dose methotrexate inhibited lung metastasis of osteosarcoma through its antiangiogenic activity. Our results indicate that low-dose methotrexate is a promising drug for tumor dormancy therapy in patients with osteosarcoma and lung metastasis.

Radiosurgical palliation of aggressive murine SCCVII squamous cell carcinomas using synchrotron-generated X-ray microbeams

Microbeam radiosurgery (MBRS), also referred to as microbeam radiation therapy (MRT), was tested at the European Synchrotron Radiation Facility (ESRF). The left tibiofibular thigh of a mouse bearing a subcutaneously (sc) implanted mouse model (SCCVII) of aggressive human squamous-cell carcinoma was irradiated in two orthogonal exposures with or without a 16 mm aluminium filter through a multislit collimator (MSC) by arrays of nearly parallel microbeams spaced 200 microm on centre (oc). The peak skin-entrance dose from each exposure was 442 Gy, 625 Gy, or 884 Gy from 35 microm wide beams or 442 Gy from 70 microm wide beams. The 442/35, 625/35, 884/35 and 442/70 MBRSs yielded 25 day, 29 day, 37 day and 35 day median survival times (MST) (post-irradiation), respectively, exceeding the 20 day MST from 35 Gy-irradiation of SCCVIIs with a seamless 100 kVp X-ray beam.

A phenolic compound, 5-caffeoylquinic acid (chlorogenic acid), is a new type and strong matrix metalloproteinase-9 inhibitor: Isolation and identification from methanol extract of Euonymus alatus

A phenolic compound responsible for anti-MMP-9, which is known to be involved in tumor cell invasion and metastasis, has been isolated from methanol extracts prepared from stem barks of Euonymus alatus by assay-guided fractionation. The compound has been identified as 5-caffeoylquinic acid (chlorogenic acid; CHA) by NMR and FAB-MS. CHA showed a strong inhibitory effect of matrix metalloproteinase (MMP)-9 activity in a concentration-dependent manner on zymography. The purified CHA inhibited MMP-9 activity with the IC50 of 30-50 nM. Furthermore, the cytotoxic survival curve showed that CHA does not have cytotoxic effects on cellular proliferation, when Hep3B cells were treated with various concentrations of CHA and cell viability was measured using the XTT assay. The present data suggest a clue for possible mechanisms of cancer chemoprevention by CHA and other naturally occurring phenolic compounds. The results also imply that useful cancer chemopreventive agents can be further identified by combinations of in vitro (as a first screen) and in vivo studies.

Matrix metalloproteinase inhibitor MMI-166 inhibits lymphogenous metastasis in an orthotopically implanted model of lung cancer

Matrix metalloproteinases (MMP) are considered to be critically involved in tumor invasion and the metastasis of various cancers. MMI-166 is a selective inhibitor of matrix metalloproteinase (MMP-2, MMP-9, and MMP-14). The purpose of this study was to evaluate the effects of MMI-166 on both the growth of the implanted tumor and the lymph node metastasis of the mediastinum and prolonging the life span, using an orthotopic implantation model of the Ma44-3 cancer cell line. We examined the anti-invasive effect of MMI-166 in lung cancer cell lines using an in vitro invasion assay. Next, we examined the anticancer effect of MMI-166 in vivo. MMI-166 (200 mg/kg body weight) or a vehicle was administered orally to the orthotopically implanted lung cancer model. MMI-166 dose-dependently inhibited the invasion of cancer cell lines with expressions of MMP-2 and/or MMP-9 in vitro. In vivo, MMI-166 significantly inhibited mediastinal lymph node metastasis in this orthotopic model (weight of the mediastinum: control, 0.089 +/- 0.009 versus MMI-166, 0.069 +/- 0.008 mg; P = 0.005; metastatic area: control, 93,495 +/- 55,747 versus MMI-166, 22,747 +/- 17,478 pixels; P = 0.045). MMI-166 prolonged the life span by 6 days in median survival time in the orthotopically implanted model (P = 0.039). These results showed that MMI-166 could possibly inhibit lymph node metastasis and prolong the life span in lung cancer patients.

Receptor for advanced glycation end products (RAGE) and its ligand, amphoterin are overexpressed and associated with prostate cancer development

BACKGROUND

Advanced glycation end products (AGE) are produced with normal aging. Recently, some reports indicated that the interaction between AGE and the cognate receptor (RAGE) has a role in cancer dependent.

METHODS

We investigated RAGE and amphoterin mRNA expression in prostate cancer cell lines (DU145, PC-3, and LNCaP cells), hormone-refractory prostate cancer tissues, and paired untreated primary prostate cancer and normal prostate (including benign prostatic hypertrophy (BPH)) tissues using real-time quantitative PCR. Moreover, to confirm the AGE-RAGE interaction in prostate cancer, DU145 cells stimulated with AGE-bovine serum albumin (AGE-BSA) were examined by in vitro matrigel assay, cell viability assay, MTT assay, reverse transcription-polymerase chain reaction (RT-PCR), and Western blot.

RESULTS

DU145 cells, a hormone-independent prostate cancer cell line, showed the highest RAGE mRNA expression. Amphoterin mRNA was expressed in all three cell lines. In prostate tissues, untreated prostate cancer tissue and hormone-refractory prostate cancer tissue showed higher RAGE and amphoterin mRNA expression than normal prostate tissue. The AGE-RAGE interaction induced the invasion and growth in DU145 cells stimulated with AGE-BSA.

CONCLUSIONS

The AGE-RAGE interaction is important in prostate cancer development, and inhibition of this interaction has potential as a new molecular target for cancer therapy or prevention.

Novel and therapeutic effect of caffeic acid and caffeic acid phenyl ester on hepatocarcinoma cells: complete regression of hepatoma growth and metastasis by dual mechanism

Our previous studies have clearly shown that the angiogenic enzymes, matrix metalloproteinase (MMP) -2/9, are directly involved in human hepatic tumorigenesis and metastasis and suggest that the MMP-2/9 inhibitors, which have dual inhibitory activities on enzyme activity and transcription, represent the best candidates for achieving tumor regression. Many anti-cancer drugs have strong cellular cytotoxicity and side effects, indicating that strong anti-cancer drugs that have no or minimal cytotoxicity and side effects need to be developed. The specific aim of the present study was to develop powerful anti-cancer drugs with specific tumor regression and anti-metastatic potential having the dual inhibitory activities of specific MMP-2 and -9 enzyme activities and gene transcription at the molecular level. Caffeic acid (CA), a strong and selective MMP-9 activity and transcription inhibitor, was isolated from the plant Euonymus alatus and its derivative, caffeic acid phenethyl ester (CAPE), was synthesized. CA and CAPE selectively inhibited MMP-2 and -9 but not -1, -3, -7, or cathepsin K. Treatment of HepG2 cells with CA (100 microg/mL) and CAPE (5 microg/mL) suppressed phorbol 12-myristate 13-acetate (PMA) -induced MMP-9 expression by inhibiting the function of NF-kappaB, but not AP-1. We confirmed that CA and CAPE suppressed the growth of HepG2 tumor xenografts in nude mice in vivo. The subcutaneous and oral administrations of CA and CAPE significantly reduced the liver metastasis. These results confirm the therapeutic potential of the compounds and suggest that the anti-metastatic and anti-tumor effects of CA and CAPE are mediated through the selective suppression of MMP-9 enzyme activity and transcriptional down-regulation by the dual inhibition of NF-kappaB as well as MMP-9 catalytic activity.

Inostamycin suppresses vascular endothelial growth factor-stimulated growth and migration of human umbilical vein endothelial cells

Angiogenesis involves multiple steps including proliferation and migration of endothelial cells. In the present study, we determined the effect of inostamycin (an inhibitor of phosphatidylinositol synthesis) on vascular endothelial growth factor (VEGF)-induced proliferation and migration of human umbilical vein endothelial cells (HUVECs). Inostamycin significantly attenuated both VEGF-induced proliferation and migration of HUVECs. Inostamycin inhibited activation of mitogen-activated kinases (ERK and p38) and elevation of cyclin D1 induced by VEGF. These data suggest that inostamycin reduced both proliferation and migration of HUVECs by targeting ERK-cyclin D1 and p38, respectively.

Anti-invasive, antitumoral, and antiangiogenic efficacy of a pyrimidine-2,4,6-trione derivative, an orally active and selective matrix metalloproteinases inhibitor

PURPOSE

The implication of matrix metalloproteinases (MMPs) in the major stages of cancer progression has fueled interest in the design of synthetic MMP inhibitors (MMPIs) as a novel anticancer therapy. Thus far, drugs used in clinical trials are broad-spectrum MMPIs the therapeutic index of which proved disappointingly low. The development of selective MMPIs for tumor progression-associated MMPs is, thus, likely to offer improved therapeutic possibilities.

EXPERIMENTAL DESIGN

The anti-invasive capacity of a series of pyrimidine-trione derivatives was tested in vitro in a chemoinvasion assay, and the most potent compound was further evaluated in vivo in different human tumor xenograft models. The activity of this novel selective MMPI was compared with BB-94, a broad-spectrum inhibitor.

RESULTS

Ro-28-2653, an inhibitor with high selectivity for MMP-2, MMP-9, and membrane type 1 (MT1)-MMP, showed the highest anti-invasive activity in vitro. In vivo, Ro-28-2653 reduced the growth of tumors induced by the inoculation of different cell lines producing MMPs and inhibited the tumor-promoting effect of fibroblasts on breast adenocarcinoma cells. Furthermore, Ro-28-2653 reduced tumor vascularization and blocked angiogenesis in a rat aortic ring assay. In contrast, BB-94 up-regulated MMP-9 expression in tumor cells and promoted angiogenesis in the aortic ring assay.

CONCLUSION

Ro-28-2653, a selective and orally bioavailable MMPI with inhibitory activity against MMPs expressed by tumor and/or stromal cells, is a potent antitumor and antiangiogenic agent. In contrast to broad-spectrum inhibitors, the administration of Ro-28-2653 was not associated with the occurrence of adverse side effects that might hamper the therapeutic potential of these drugs.

Novel therapeutic targets in squamous cell carcinoma of the head and neck

The treatment of squamous cell carcinoma of the head and neck (SCCHN) has recently witnessed the introduction of molecularly targeted agents based on disease biology, target discovery, and validation. One class of agents, the epidermal growth factor receptor (EGFR) inhibitors, is currently in phase III trials. There are multiple processes, however, that appear to be suitable for targeted therapy beyond EGFR. These include signal transduction, cell cycle control, prostaglandin synthesis, protein degradation, hypoxia, and angiogenesis. These systems and specific protein targets will be reviewed in detail with emphasis on promising preclinical and early clinical evidence of activity.

Small cell lung cancer: the importance of the extracellular matrix

Lung cancer is the leading cause of cancer deaths in the UK and the small cell lung cancer (SCLC) phenotype is the most aggressive form of this disease, with a high metastatic potential and the development of resistance to chemotherapy. Evidence now suggests that these features may be due to important links between the cancer cells and proteins in their local extracellular matrix (ECM). This article reviews the evidence for a chemoprotective effect of extracellular matrix in small cell lung cancer and discusses the importance of integrin-mediated signalling pathways in this setting.

Metalloproteinase-2 expression correlates with aggressiveness of cutaneous squamous cell carcinomas

Matrix metalloproteinases compose a family of enzymes involved in degradation of the extracellular matrix. Tumor cells must penetrate the basement membrane and traverse the extracellular matrix in order to invade surrounding structures and metastasize to distant sites. Gelatinases, particularly gelatinase A (matrix metalloproteinase-2), demonstrate degradative activity against components of the basement membrane and may be involved in the progression of in situ squamous cell carcinoma lesions. Matrix metalloproteinase-2 overexpression has been correlated with tumor invasiveness and metastasis in a wide variety of cancer types, including squamous cell carcinoma arising on mucous membranes. However, correlation between matrix metalloproteinase-2 overexpression and the spread and prognosis of cutaneous squamous cell carcinoma has not been characterized in the literature at present. In this study, we used immunohistochemical techniques to examine the expression of matrix metalloproteinase-2 in 10 actinic keratosis, 15 in situ, 13 invasive, 13 primary (with documented metastatic disease), 11 metastatic, and 8 recurrent squamous cell carcinoma cases. We found that while the average staining intensity (scale 0-3+, 3+ being strongest) of actinic keratosis and in situ lesions was not statistically significant (0.87-1.3 and 0.75-1.4, respectively), the average staining intensity of invasive squamous cell carcinomas (1.6-2.5) was significantly greater than that of actinic keratosis and in situ lesions. Likewise, while the average staining intensity of primary squamous cell carcinomas and metastatic squamous cell carcinomas was not found to be statistically significant (3.1-3.5 and 3.1-3.8, respectively), the average staining intensity of these lesions was significantly higher than that of invasive lesions. We also found that the intensity of matrix metalloproteinase-2 staining correlates with cellular atypia, inflammation, neovascularization, and the invasive tumor front, as well as tumor aggressiveness, and may play a role in the pathogenesis, invasion, and metastasis of cutaneous squamous cell carcinoma.

Therapy for chronic obstructive pulmonary disease in the 21st century

Chronic obstructive pulmonary disease (COPD) is a common, smoking-related, severe respiratory condition characterised by progressive, irreversible airflow limitation. Current treatment of COPD is symptomatic, with no drugs capable of halting the relentless progression of airflow obstruction. Better understanding of the airway inflammation, oxidative stress and alveolar destruction that characterise COPD has delineated new disease targets, with consequent identification of novel compounds with therapeutic potential. These new drugs include aids to smoking cessation (e.g. bupropion) and improvements to existing therapies, for example long-acting rather than short-acting bronchodilators, as well as combination therapy. New antiproteases include acyl-enzyme and transition state inhibitors of neutrophil elastase (e.g. sivelestat and ONO-6818), matrix metalloprotease inhibitors (e.g. batimastat), cathepsin inhibitors and peptide protease inhibitors (e.g. DX-890 [EPI-HNE-4] and trappin-2). New antioxidants include superoxide dismutase mimetics (e.g. AEOL-10113) and spin trap compounds (e.g. N-tert-butyl-alpha-phenylnitrone). New anti-inflammatory interventions include phosphodiesterase-4 inhibitors (e.g. cilomilast), inhibitors of tumour necrosis factor-alpha (e.g. humanised monoclonal antibodies), adenosine A(2a) receptor agonists (e.g. CGS-21680), adhesion molecule inhibitors (e.g. bimosiamose [TBC1269]), inhibitors of nuclear factor-kappaB (e.g. the naturally occurring compounds hypoestoxide and (-)-epigallocatechin-3-gallate) and activators of histone deacetylase (e.g. theophylline). There are also selective inhibitors of specific extracellular mediators such as chemokines (e.g. CXCR2 and CCR2 antagonists) and leukotriene B(4) (e.g. SB201146), and of intracellular signal transduction molecules such as p38 mitogen activated protein kinase (e.g. RWJ67657) and phosphoinositide 3-kinase. Retinoids may be one of the few potential treatments capable of reversing alveolar destruction in COPD, and a number of compounds are in clinical trial (e.g. all-trans-retinoic acid). Talniflumate (MSI-1995), an inhibitor of human calcium-activated chloride channels, has been developed to treat mucous hypersecretion. In addition, the purinoceptor P2Y(2) receptor agonist diquafosol (INS365) is undergoing clinical trials to increase mucus clearance. The challenge to transferral of these new compounds from preclinical research to disease management is the design of effective clinical trials. The current scarcity of well characterised surrogate markers predicts that long-term studies in large numbers of patients will be needed to monitor changes in disease progression.

Drug-induced apoptosis by a matrix metalloproteinase inhibitor, SI-27 on human malignant glioma cell lines; in vitro study

Matrix metalloproteinase (MMP) plays important roles in cell invasion and tumor angiogenesis. SI-27, an anti-MMP agent, has already been shown to possess both in vitro anti-invasive and anti-angiogenic properties against malignant gliomas in non-cytotoxic dose concentrations. However, to the best of our knowledge, the molecular mechanism mediating the cytotoxic action by this agent and the molecular mechanism in the cytotoxic action against malignant glioma cell have not yet been clarified. Therefore, we assessed the effect in the cytotoxic dose concentrations to investigate whether this cytotoxic action is related to apoptosis in this study. The effect on human glioma cell lines (U87MG, U251MG, and U373MG) was examined by transmission electron microscope, agarose gel electrophoresis with the DNA fragmentation, flow cytometry with FITC-conjugated Annexin V, and detection of caspase activity. Drug-induced apoptosis was observed in the cytotoxic dose. The result indicated that the cytotoxity of SI-27 might be related to the drug-induced apoptosis mediated by caspase.

Angiogenesis: vascular remodeling of the extracellular matrix involves metalloproteinases

Endothelial cell invasion is an essential event during angiogenesis (the formation of new blood vessels). This process involves the degradation of the extracellular matrix, the basement membrane, and interstitial stroma, and is governed by the activation of matrix metalloproteinases. However, the contribution of matrix metalloproteinases in angiogenesis is much more complicated. Tumor growth above a certain size is dependent on new vessels. A number of studies have demonstrated that treating tumors with matrix metalloproteinase inhibitors results in tumor reduction and a decrease in tumor angiogenesis. Matrix metalloproteinases as sole matrix eaters or degraders is a matter of the past. Not only tumor cells but more importantly bystander cells such as stromal cells produce matrix metalloproteinases. Matrix metalloproteinases therefore are also part of the pathologic microenvironment in different diseases. This enzymatic microenvironment dictates the endothelial cell fate, the angiogenic switch, and finally angiogenesis. During recent years, the role of matrix metalloproteinases has expanded, and their function as modulators of biologically active signaling molecules has drawn much attention. Depending on their substrate (growth factors or their receptors, extracellular matrix components, and angiogenic factors), matrix metalloproteinase activation results in the generation of proangiogenic or antiangiogenic factors. These data challenge the old concept that matrix metalloproteinases are simply proangiogenic. The knowledge of the local enzymatic profile and what, where, and how matrix metalloproteinases are involved in angiogenesis of tumors or other diseases will help design future therapeutic strategies better reflecting the complexity of the underlying biologic process of angiogenesis.