Adenovirus-mediated overexpression of tissue inhibitor of metalloproteinases-1 in the liver: efficient protection against T-cell lymphoma and colon carcinoma metastasis

Metalloproteinases and Their Inhibitors: Potential for the Development of New Therapeutics

The metalloproteinase (MP) family of zinc-dependent proteases, including matrix metalloproteinases (MMPs), a disintegrin and metalloproteases (ADAMs), and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) plays a crucial role in the extracellular matrix (ECM) remodeling and degradation activities. A wide range of substrates of the MP family includes ECM components, chemokines, cell receptors, and growth factors. Metalloproteinases activities are tightly regulated by proteolytic activation and inhibition via their natural inhibitors, tissue inhibitors of metalloproteinases (TIMPs), and the imbalance of the activation and inhibition is responsible in progression or inhibition of several diseases, e.g., cancer, neurological disorders, and cardiovascular diseases. We provide an overview of the structure, function, and the multifaceted role of MMPs, ADAMs, and TIMPs in several diseases via their cellular functions such as proteolysis of other cell signaling factors, degradation and remodeling of the ECM, and other essential protease-independent interactions in the ECM. The significance of MP inhibitors targeting specific MMP or ADAMs with high selectivity is also discussed. Recent advances and techniques used in developing novel MP inhibitors and MP responsive drug delivery tools are also reviewed.

TIMPs: versatile extracellular regulators in cancer

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

Intravenous transfusion of endothelial progenitor cells that overexpress vitamin D receptor inhibits atherosclerosis in apoE-deficient mice

Endothelial progenitor cells (EPCs) are widely used for angiogenic therapies, as well as predictive biomarkers to assess cardiovascular disease risk. However, it is unknown that whether overexpressed vitamin D receptor (VDR) in EPCs could help EPCs counteracting atherosclerotic risks. Here, we study intravenous transplantation of genetically modified EPCs over-expressing VDR in regulating endothelial dysfunction and spontaneously arising atherosclerotic plaques of ApoE-deficient mice. Firstly, we found that over-expression of VDR in EPCs could reduce atherosclerotic plaque formation in transplanted ApoE-/- mice. In addition, the concentration of serum HDL-C in ovVDR-EPCs group was much higher than that in control groups (ApoE-/- mice without injection or injected with fresh medium or adenovirus vector). While concentrations of serum total cholesterol, LDL-C, apoB and Lp (a) were negatively correlated with the expression level of VDR. What's more, improved serum concentration of NO and elevated serum and vessel wall expression of eNOS were observed in ovVDR-EPCs group. Furthermore, reduced expression and activity of MMP2, and elevated expression and activity of TIMP2 were detected in ovVDR-EPCs group. Taken together, intravenous transfusion of EPCs that overexpress VDR significantly inhibited atherosclerosis in ApoE-deficient mice and could be used as a potential method for angiogenic therapy.

Investigating the Radioresistant Properties of Lung Cancer Stem Cells in the Context of the Tumor Microenvironment

Lung cancer is the most common cause of cancer-related deaths worldwide and non-small cell lung cancer (NSCLC) accounts for ~85% of all lung cancer. While recent research has shown that cancer stem cells (CSC) exhibit radioresistant and chemoresistant properties, current cancer therapy targets the bulk of the tumor burden without accounting for the CSC and the contribution of the tumor microenvironment. CSC interaction with the stroma enhances NSCLC survival, thus limiting the efficacy of treatment. The aim of this study was to elucidate the role of CSC and the microenvironment in conferring radio- or chemoresistance in an in vitro tumor model for NSCLC. The novel in vitro three-dimensional (3D) NSCLC model of color-coded tumor tissue analogs (TTA) that we have developed is comprised of human lung adenocarcinoma cells, fibroblasts, endothelial cells and NSCLC cancer stem cells maintained in low oxygen conditions (5% O2) to recapitulate the physiologic conditions in tumors. Using this model, we demonstrate that a single 5 Gy radiation dose does not inhibit growth of TTA containing CSC and results in elevated expression of cytokines (TGF-α, RANTES, ENA-78) and factors (vimentin, MMP and TIMP), indicative of an invasive and aggressive phenotype. However, combined treatment of single dose or fractionated doses with cisplatin was found to either attenuate or decrease the proliferative effect that radiation exposure alone had on TTA containing CSC maintained in hypoxic conditions. In summary, we utilized a 3D NSCLC model, which had characteristics of the tumor microenvironment and tumor cell heterogeneity, to elucidate the multifactorial nature of radioresistance in tumors.

Preparation of microspheres encapsulating a recombinant TIMP-1 adenovirus and their inhibition of proliferation of hepatocellular carcinoma cells

OBJECTIVE

The study aim was to prepare poly-DL-lactide-poly (PELA) microspheres encapsulating recombinant tissue inhibitors of metalloproteinase-1 (TIMP-1) in an adenovirus to investigate its inhibition on the proliferation of hepatocellular carcinoma cells HepG2.

METHODS

Microspheres were prepared by encapsulating the recombinant TIMP-1 adenovirus into biodegradable PELA. The particle size, viral load, encapsulation efficiency and in-vitro release were measured. Microspheres were used to infect HepG2 cells, then infection efficiency was examined under a fluorescent microscope and ultrastructural changes assessed by TEM. Expression of TIMP-1 mRNA in HepG2 cells was examined by semi-quantitative RT-PCR and proliferation by MTT and cell growth curve assays.

RESULTS

We successfully prepared microspheres encapsulating recombinant TIMP-1 adenovirus with a diameter of 1.965μm, an encapsulation efficiency of 60.0%, a viral load of 10.5?108/mg and approximate 60% of virus release within 120 h, the total releasing time of which was longer than 240 h. The microspheres were confirmed to be non-toxic with blank microspheres. Infected HepG2 cells could stably maintain in-vitro expression of TIMP-1, with significantly effects on biological behaviour.

CONCLUSION

PELA microspheres encapsulating a recombinant TIMP-1 adenovirus can markedly inhibit the proliferation of HepG2 cells, which provides an experimental basis for polymer/chemistry-based gene therapy of hepatocellular carcinomas.

Liver acid sphingomyelinase inhibits growth of metastatic colon cancer

Acid sphingomyelinase (ASM) regulates the homeostasis of sphingolipids, including ceramides and sphingosine-1-phosphate (S1P). These sphingolipids regulate carcinogenesis and proliferation, survival, and apoptosis of cancer cells. However, the role of ASM in host defense against liver metastasis remains unclear. In this study, the involvement of ASM in liver metastasis of colon cancer was examined using Asm-/- and Asm+/+ mice that were inoculated with SL4 colon cancer cells to produce metastatic liver tumors. Asm-/- mice demonstrated enhanced tumor growth and reduced macrophage accumulation in the tumor, accompanied by decreased numbers of hepatic myofibroblasts (hMFs), which express tissue inhibitor of metalloproteinase 1 (TIMP1), around the tumor margin. Tumor growth was increased by macrophage depletion or by Timp1 deficiency, but was decreased by hepatocyte-specific ASM overexpression, which was associated with increased S1P production. S1P stimulated macrophage migration and TIMP1 expression in hMFs in vitro. These findings indicate that ASM in the liver inhibits tumor growth through cytotoxic macrophage accumulation and TIMP1 production by hMFs in response to S1P. Targeting ASM may represent a new therapeutic strategy for treating liver metastasis of colon cancer.

Opposite effects of tissue inhibitor of metalloproteinases-1 (TIMP-1) over-expression and knockdown on colorectal liver metastases

Background

Tissue inhibitors of metalloproteinases (TIMPs) and the corresponding metalloproteinases are integral parts of the protease network and have been shown to be involved in cancer development and metastasis. Paradoxically, for TIMP-1, tumor promoting as well as tumor inhibitory effects have been observed.

Methods

To address this paradox, we utilized the BALB/c/CT26 mouse model that reliably leads to liver metastasis after splenic tumor cell injection and variegated the type of target cells for therapeutic intervention and the modalities of gene transfer. Since we have observed before that over-expression of TIMP-1 in liver host cells leads to efficient tumor growth inhibition in this model, we now examined whether targeting the tumor cells themselves will have a similar effect.

Results

In concordance with the earlier results, TIMP-1 over-expression in tumor cells led to a dramatic reduction of tumor growth as well. To evaluate any influence of treatment modality, we further examined whether TIMP-1 knockdown in the same animal model would have the opposite effect on tumor growth than TIMP-1 over-expression. Indeed, TIMP-1 knockdown led to a marked increase in tumor burden.

Conclusion

These data indicate that in the BALB/c/CT26 model, the modification of TIMP-1 has concordant effects irrespective of the type of target cell or the technique of modulation of TIMP-1 activity, and that TIMP-1 is unequivocally tumor inhibitory in this model.

Down-regulation of CXCL1 inhibits tumor growth in colorectal liver metastasis

As part of ongoing studies to obtain a global picture of invasion related events in colorectal liver metastases, here, we report our findings on gene expression of the pro-angiogenic subgroup of chemokines, the CXCL-ELR+ chemokines. Apart from their pro-angiogenic and chemoattractant function, these chemokines appear to also contribute to tumor cell transformation, growth and invasion. In our nude mouse model of colorectal liver metastases, we found CXCL1,2,3,5 and 8 (IL-8) to be up-regulated in the tumor cells of the invasion front as compared to the tumor cells in the inner parts of the tumor. ShRNA mediated down-regulation of the most prominently up-regulated group member, CXCL1/gro-alpha resulted in inhibition of cell viability, invasion and proliferation. In vivo, down-regulation of CXCL1 resulted in a nearly complete prevention of tumor growth in nude mice. Mechanistically, auto-regulatory mechanisms involving NF-kappaB and Akt appear to be involved in pro-tumorigenic functions of CXCL1.

Dietary walnuts inhibit colorectal cancer growth in mice by suppressing angiogenesis

OBJECTIVE

Animal studies have demonstrated that dietary supplementation with flaxseed oil inhibits colorectal cancer growth. Recent data indicate that walnuts have strong antiproliferative properties against colon cancer cells in vitro but no previous study has assessed the effects of walnuts in vivo or performed a joint evaluation of flaxseed oil and walnuts. The aim of the present study was to examine the effect of dietary walnuts on colorectal cancer in vivo and to comparatively evaluate their efficacy in relation to flaxseed oil.

METHODS

HT-29 human colon cancer cells were injected in 6-wk-old female nude mice. After a 1-wk acclimation period, mice (n = 48) were randomized to diets containing ∼19% of total energy from walnuts, flaxseed oil, or corn oil (control) and were subsequently studied for 25 d.

RESULTS

Tumor growth rate was significantly slower in walnut-fed and flaxseed-fed mice compared with corn oil-fed animals (P < 0.05) by 27% and 43%, respectively. Accordingly, final tumor weight was reduced by 33% and 44%, respectively (P < 0.05 versus control); the differences between walnut and flaxseed diets did not reach significance. We found no differences among groups in metabolic and hormonal profile, serum antioxidant capacity, or inflammation (P > 0.05). However, walnuts and flaxseed oil significantly reduced serum expression levels of angiogenesis factors, including vascular endothelial growth factor (by 30% and 80%, respectively), and approximately doubled total necrotic areas despite smaller tumor sizes (P < 0.05 versus control). Dietary walnuts significantly decreased angiogenesis (CD34 staining; P = 0.017 versus control), whereas this effect did not reach significance in the flaxseed oil group (P = 0.454 versus control).

CONCLUSION

We conclude that walnuts in the diet inhibit colorectal cancer growth by suppressing angiogenesis. Further studies are needed to confirm our findings in humans and explore underlying mechanisms.

Tumor cell-derived Timp-1 is necessary for maintaining metastasis-promoting Met-signaling via inhibition of Adam-10

In many different tumor entities, increased expression of tissue inhibitor of metalloproteinases-1 (Timp-1) is associated with poor prognosis. We previously reported in mouse models that elevated systemic levels of Timp-1 induce a gene expression signature in the liver microenvironment increasing the susceptibility of this organ to tumor cells. This host effect was dependent on increased activity of the hepatocyte growth factor (Hgf)/hepatocyte growth factor receptor (Met) signaling pathway. In a recent study we showed that Met signaling is regulated by Timp-1 as it inhibits the Met sheddase A disintegrin and metalloproteinase-10 (Adam-10). The aim of the present study was to elucidate whether the metastatic potential of tumor cells benefits from autocrine Timp-1 as well and involves Adam-10 and Met signaling. In a syngeneic murine model of experimental liver metastasis Timp-1 expression and Met signaling were localized within metastatic colonies and expressed by tumor cells. Knock down of tumor cell Timp-1 suppressed Met signaling in metastases and inhibited metastasis formation and tumor cell-scattering in the liver. In vitro, knock down of tumor cell Timp-1 prevented Hgf-induced Met phosphorylation. Consequently, knock down of Met sheddase Adam-10 triggered auto-phosphorylation and responsiveness to Hgf. Accordingly, Adam-10 knock down increased Met phosphorylation in metastatic foci and induced tumor cell scattering into the surrounding liver parenchyma. In conclusion, these findings show that tumor cell-derived Timp-1 acts as a positive regulator of the metastatic potential and support the concept that proteases and their natural inhibitors, as members of the protease web, are major players of signaling during normal homeostasis and disease.

Tissue inhibitor of metalloproteinase 1 expression associated with gene demethylation confers anoikis resistance in early phases of melanocyte malignant transformation

Although anoikis resistance has been considered a hallmark of malignant phenotype, the causal relation between neoplastic transformation and anchorage-independent growth remains undefined. We developed an experimental model of murine melanocyte malignant transformation, where a melanocyte lineage (melan-a) was submitted to sequential cycles of anchorage blockade, resulting in progressive morphologic alterations, and malignant transformation. Throughout this process, cells corresponding to premalignant melanocytes and melanoma cell lines were established and show progressive anoikis resistance and increased expression of Timp1. In melan-a melanocytes, Timp1 expression is suppressed by DNA methylation as indicated by its reexpression after 5-aza-2'-deoxycytidine treatment. Methylation-sensitive single-nucleotide primer extension analysis showed increased demethylation in Timp1 in parallel with its expression along malignant transformation. Interestingly, TIMP1 expression has already been related with negative prognosis in some human cancers. Although described as a MMP inhibitor, this protein has been associated with apoptosis resistance in different cell types. Melan-a cells overexpressing Timp1 showed increased survival in suspension but were unable to form tumors in vivo, whereas Timp1-overexpressing melanoma cells showed reduced latency time for tumor appearance and increased metastatic potential. Here, we demonstrated for the first time an increment in Timp1 expression since the early phases of melanocyte malignant transformation, associated to a progressive gene demethylation, which confers anoikis resistance. In this way, Timp1 might be considered as a valued marker for melanocyte malignant transformation.

Long-term expression of tissue-inhibitor of matrix metalloproteinase-1 in the murine central nervous system does not alter the morphological and behavioral phenotype but alleviates the course of experimental allergic encephalomyelitis

Tissue inhibitors of metalloproteinases (TIMPs) are a family of closely related proteins that inhibit matrix metalloproteinases (MMPs). In the central nervous system (CNS), TIMPs 2, 3, and 4 are constitutively expressed at high levels, whereas TIMP1 can be induced by various stimuli. Here, we studied the effects of constitutive expression of TIMP1 in the CNS in transgenic mice. Transgene expression started prenatally and persisted throughout lifetime at high levels. Since MMP activity has been implicated in CNS development, in proper function of the adult CNS, and in inflammatory disorders, we investigated Timp1-induced CNS alterations. Despite sufficient MMP inhibition, high expressor transgenic mice had a normal phenotype. The absence of compensatory up-regulation of MMP genes in the CNS of Timp1 transgenic mice indicates that development, learning, and memory functions do not require the entire MMP arsenal. To elucidate the effects of strong Timp1 expression in CNS inflammation, we induced experimental allergic encephalomyelitis. We observed a Timp1 dose-dependent mitigation of both experimental allergic encephalomyelitis symptoms and histological lesions in the CNS of transgenic mice. All in all, our data demonstrate that (1) long-term CNS expression of TIMP1 with complete suppression of gelatinolytic activity does not interfere with physiological brain function and (2) TIMP1 might constitute a promising candidate for long-term therapeutic treatment of inflammatory CNS diseases such as multiple sclerosis.

Inhibition of tumor cell growth in the liver by RNA interference-mediated suppression of HIF-1alpha expression in tumor cells and hepatocytes

Hypoxia-inducible factor-1 (HIF-1) is a ubiquitously expressed oxygen-regulated transcription factor composed of alpha and beta subunits. HIF-1 activates transcription of various genes including those involved in metastatic tumor growth. In the present study, HIF-1alpha expression in tumor-bearing mouse liver was examined after inoculation of tumor cells into portal vein. We found that tumor-bearing liver showed greatly increased HIF-1alpha expression. Plasmid DNA (pDNA) expressing short hairpin RNA targeting HIF-1alpha (pshHIF-1alpha) was effective in suppressing protein expression of HIF-1alpha in vitro. Intravenous injection of pshHIF-1alpha by hydrodynamics-based procedure reduced the HIF-1alpha protein expression in both normal and tumor cells and tumor cell number in the liver. Pre-injection of pshHIF-1alpha to mice, by which pDNA was delivered only to liver cells, not to tumor cells, was also effective in reducing the number of tumor cells inoculated 3 days after pDNA injection. These findings indicate that HIF-1alpha expression is increased in normal liver cells as well as tumor cells, and HIF-1alpha expression plays an important role in tumor progression. Use of the RNA interference (RNAi) of HIF-1 is an effective strategy for inhibiting tumor cell growth, and both tumor and normal cells can be the target for RNAi-based anticancer treatment.Gene Therapy (2008) 15, 572-582; doi:10.1038/sj.gt.3303103; published online 14 February 2008.

Tissue inhibitor of metalloproteinases-1 promotes liver metastasis by induction of hepatocyte growth factor signaling

Balanced expression of proteases and their inhibitors is one prerequisite of tissue homeostasis. Metastatic spread of tumor cells through the organism depends on proteolytic activity and is the death determinant for cancer patients. Paradoxically, increased expression of tissue inhibitor of metalloproteinases-1 (TIMP-1), a natural inhibitor of several endometalloproteinases, including matrix metalloproteinases and a disintegrin and metalloproteinase-10 (ADAM-10), in cancer patients is negatively correlated with their survival, although TIMP-1 itself inhibits invasion of some tumor cells. Here, we show that elevated stromal expression of TIMP-1 promotes liver metastasis in two independent tumor models by inducing the hepatocyte growth factor (HGF) signaling pathway and expression of several metastasis-associated genes, including HGF and HGF-activating proteases, in the liver. We also found in an in vitro assay that suppression of ADAM-10 is in principle able to prevent shedding of cMet, which may be one explanation for the increase of cell-associated HGF receptor cMet in livers with elevated TIMP-1. Similar TIMP-1-associated changes in gene expression were detected in livers of patients with metastatic colorectal cancer. The newly identified role of TIMP-1 to create a prometastatic niche may also explain the TIMP-1 paradoxon.

[The role of matrix metalloproteinases and tissue inhibitors of metalloproteinases in invasion of tumours of neuroepithelial tissue]

Tumour invasion requires degradation of extracellular matrix components and migration of cells through degraded structures into surrounding tissues. Matrix metalloproteinases (MMP) constitute a family of zinc and calcium-dependent endopeptidases that play a key role in the breakdown of extracellular matrix, and in processing of cytokines, growth factors, chemokines and cell surface receptors. Their activity is regulated at the levels of transcription, activation and inhibition by tissue inhibitors of metalloproteinases (TIMP). Changes in expression of MMP and TIMP are implicated in tumour invasion, because they may contribute to both migration of tumour cells and angiogenesis. Alterations of MMP expression observed in brain tumours arouse interest in the development and evaluation of synthetic matrix metalloproteinase inhibitors as antitumour agents.

The use of tissue inhibitors of matrix metalloproteinases to increase the efficacy of a tumor necrosis factor/interferonγ antitumor therapy

Owing to its impressive ability to kill tumor cells, especially in combination with interferon-gamma (IFNgamma), tumor necrosis factor (TNF) is widely appreciated as being a potential systemic therapeutic for the treatment of cancer. On the other hand, owing to its proinflammatory activities, administration of TNF leads to many systemic side effects and eventually to a potentially lethal systemic inflammatory response syndrome (SIRS). However, systemic treatment of tumor-bearing mice with TNF/IFNgamma in combination with BB-94 (a broad-spectrum metalloproteinase inhibitor) confers protection against TNF/IFNgamma-induced mortality, whereas preserving the antitumor activity. In this study, we investigated the effect of the adenoviral delivery of human tissue inhibitors of matrix metalloproteinase (hTIMP)-1 and hTIMP-2 genes on the outcome of TNF/IFNgamma antitumor therapy. The dose of adenovirus was limited to 10(8) PFU per mouse owing to the additive toxicity of combining it with TNF/IFNgamma therapy. Nevertheless, this dose was sufficient to achieve highly efficient adenoviral transfer and expression of hTIMP-1 and hTIMP-2 in the liver, but not the tumor. Treatment with this low dose of AdhTIMP-1 or AdhTIMP-2 was not enough to protect the host against the toxic effects of TNF/IFNgamma. However, it was sufficient to show a synergistic effect of hTIMPs with TNF/IFNgamma such that tumors regressed significantly faster. Interestingly, only AdTIMP-2 was able to prevent relapses after treatment.

Adenovirus-mediated expression of TIMP-1 and TIMP-2 in bone inhibits osteolytic degradation by human prostate cancer

Matrix metalloproteinases (MMPs) are proteolytic enzymes that play critical roles in the pathogenesis of human cancers. Clinical trials using synthetic small molecule MMP inhibitors have been carried out but with little success. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors that block the extracellular matrix-degrading activity of MMPs. Here, we investigated the possibilities of genetically modifying human bones with TIMPs to create a high-TIMP bone microenvironment, which is hostile to metastatic prostate cancer cells using adenovirus-mediated gene transfer technology and SCID-hu end-organ colonization mouse model. Two strategies were used to achieve bone-specific TIMP expression: (i) ex vivo bone adenoviral infection followed by in vivo bone implantation; and (ii) ex vivo BMS cell infection followed by injection into in vivo implanted human fetal bones. PC-3 prostate cancer cells were injected into human fetal bones 4 weeks after implantation in SCID mice. In vitro, adenovirus-mediated expression of TIMP-1 or TIMP-2 in bone fragments inhibited MMP-2 activity, bone turnover and prostate cancer cell-induced proteolytic degradation as determined by gelatin zymography, calcium measurement and DQ protein quenched fluorescence assay, respectively. In vivo, immunohistochemistry confirmed TIMP-2 expression in AdTIMP-2-infected bone implants 4 weeks after implantation in SCID mice. Mice receiving AdTIMP-treated bone fragments showed significantly reduced PC-3-induced osteolysis, osteoclast recruitment and bone turnover in the implanted bones. We propose that adenoviral gene transfer of TIMP-1 and TIMP-2 can prevent the proteolytic activity of prostate cancer cells in bone and that enhancing anti-proteolytic defense mechanisms in target organs represents a promising form of prostate cancer gene therapy.

Adenovirus-mediated small interfering RNA against matrix metalloproteinase-2 suppresses tumor growth and lung metastasis in mice

Matrix metalloproteinases (MMP) are a group of proteinases that have normal physiologic roles degrading and remodeling the extracellular matrix. They also have multiple roles in different stages of tumor progression. Elevated levels of MMPs have been observed in many tumors; these increases have a strong association with the invasive phenotype. MMP-2 and MMP-9 are particularly involved in cancer invasion and metastasis. MMP inhibitors are currently being tested as therapeutic agents for a number of cancers in both preclinical models and in clinical trials. To date, clinical trials using this strategy have had limited efficacy. A major concern is the lack of specificity of commercially available MMP inhibitors. An adenoviral vector expressing small interfering RNA against the MMP-2 gene (Ad-MMP-2) was constructed to specifically inhibit MMP-2 expression. The effect of Ad-MMP-2 on invasion, angiogenesis, tumor growth, and metastasis of A549 lung cancer cell was evaluated. Ad-MMP-2 infection of lung cancer cells showed specific down-regulation of MMP-2 protein, activity, and transcription as determined by Western blotting, gelatin zymography, and reverse transcription-PCR. Ad-MMP-2 inhibition also mitigated lung cancer invasion and migration, and reduced tumor cell-induced angiogenesis in vitro. In an experimental metastatic lung tumor model, treatment of established tumors by Ad-MMP-2 inhibited s.c. tumor growth and formation of lung nodules in mice. Adenoviral-mediated RNA interference against MMP-2 has significant therapeutic potential for lung cancer and exerts some of this effect by inhibiting angiogenesis.

Global analysis of host tissue gene expression in the invasive front of colorectal liver metastases

Host cell reactions are a crucial determinant for tumor invasion. We analyzed on a genomewide scale gene expression differences between microdissected tissues taken from unaffected liver tissue of a human colorectal tumor (LS174) growing in the livers of nude mice and tissue from the host part of the invasive front. Due to the low degree of interspecies cross-hybridization of 15% as determined on Affymetrix microarrays, our xenograft model allowed for the distinction of genes of murine versus human origin even if the respective tissues could not be isolated separately. Using the gene ontology (GO) classification, we were able to determine patterns of up- and downregulated genes in the liver part of the invasive front. We observed a pronounced overrepresentation, e.g., of the GO terms "extracellular matrix," "cell communication," "response to biotic stimulus," "structural molecule activity" and "cell growth," indicating a very pronounced host cell response to tumor invasion. On the single gene level, hepatic stellate cell (HSC) activation markers were overrepresented in the liver part of the invasion front. Immunohistochemistry and qPCR confirmed an activation of HSC as well as an increased number of HSC in the invasive front as compared to the noninvaded liver tissue. In summary, our data demonstrate the feasibility of an interspecies differential gene expression approach on a genomewide scale.

High level production of secreted proteins: example of the human tissue inhibitor of metalloproteinases 1

The major difficulty for high-throughput screening of therapeutic protein candidates in experimental animal models of pathologies or for structural studies is their fast and efficient production. The tissue inhibitors of metalloproteinases (TIMPs) considered to play a role in many physiological and pathological processes, such as arthritis or cancer, by inhibiting matrix metalloproteinases or acting as signalling molecules, have always been produced with huge difficulties. We hereby propose a new method to overproduce human recombinant TIMP-1 by transient expression in HEK293E cells, followed by a one-step chromatography purification, yielding in only 2 weeks, dozens of milligrams of pure, stable, glycosylated and active protein for in vitro and in vivo studies. This easy to set up, rapid, and efficient method could be applied for any naturally secreted mammalian protein.