Tumor epithelial cell matrix metalloproteinase 9 is a target for antimetastatic therapy in colorectal cancer

Monotropein Induced Apoptosis and Suppressed Cell Cycle Progression in Colorectal Cancer Cells

OBJECTIVE

To determine whether monotropein has an anticancer effect and explore its potential mechanisms against colorectal cancer (CRC) through network pharmacology and molecular docking combined with experimental verification.

METHODS

Network pharmacology and molecular docking were used to predict potential targets of monotropein against CRC. Cell counting kit assay, plate monoclonal assay and microscopic observation were used to investigate the antiproliferative effects of monotropein on CRC cells HCT116, HT29 and LoVo. Flow cytometry and scratch assay were used to analyze apoptosis and cell cycle, as well as cell migration, respectively in HCT116, HT29, and LoVo cells. Western blotting was used to detect the expression of proteins related to apoptosis, cell cycle, and cell migration, and the expression of proteins key to the Akt pathway.

RESULTS

The Gene Ontology and Reactome enrichment analyses indicated that the anticancer potential of monotropein against CRC might be involved in multiple cancer-related signaling pathways. Among these pathways, RAC-beta serine/threonine-protein kinase (Akt1, Akt2), cyclin-dependent kinase 6 (CDK6), matrix metalloproteinase-9 (MMP9), epidermal growth factor receptor (EGFR), cell division control protein 42 homolog (CDC42) were shown as the potential anticancer targets of monotropein against CRC. Molecular docking suggested that monotropein may interact with the 6 targets (Akt1, Akt2, CDK6, MMP9, EGFR, CDC42). Subsequently, cell activity of HCT116, HT29 and LoVo cell lines were significantly suppressed by monotropein (P<0.05). Furthermore, our research revealed that monotropein induced cell apoptosis by inhibiting Bcl-2 and increasing Bax, induced G1-S cycle arrest in colorectal cancer by decreasing the expressions of CyclinD1, CDK4 and CDK6, inhibited cell migration by suppressing the expressions of CDC42 and MMP9 (P<0.05), and might play an anticancer role through Akt signaling pathway.

CONCLUSION

Monotropein exerts its antitumor effects primarily by arresting the cell cycle, causing cell apoptosis, and inhibiting cell migration. This indicates a high potential for developing novel medication for treating CRC.

Elucidating the Role of Innate and Adaptive Immune Responses in the Pathogenesis of Canine Chronic Inflammatory Enteropathy-A Search for Potential Biomarkers

Simple Summary

Canine chronic inflammatory enteropathy (CIE) is a chronic disease affecting the small or large intestine and, in some cases, the stomach of dogs. This gastrointestinal disorder is common and is characterized by recurrent vomiting, diarrhea, and weight loss in affected dogs. The pathogenesis of IBD is not completely understood. Similar to human IBD, potential disease factors include genetics, environmental exposures, and dysregulation of the microbiota and the immune response. Some important components of the innate and adaptive immune response involved in CIE pathogenesis have been described. However, the immunopathogenesis of the disease has not been fully elucidated. In this review, we summarized the literature associated with the different cell types and molecules involved in the immunopathogenesis of CIE, with the aim of advancing the search for biomarkers with possible diagnostic, prognostic, or therapeutic utility.

Abstract

Canine chronic inflammatory enteropathy (CIE) is one of the most common chronic gastrointestinal diseases affecting dogs worldwide. Genetic and environmental factors, as well as intestinal microbiota and dysregulated host immune responses, participate in this multifactorial disease. Despite advances explaining the immunological and molecular mechanisms involved in CIE development, the exact pathogenesis is still unknown. This review compiles the latest reports and advances that describe the main molecular and cellular mechanisms of both the innate and adaptive immune responses involved in canine CIE pathogenesis. Future studies should focus research on the characterization of the immunopathogenesis of canine CIE in order to advance the establishment of biomarkers and molecular targets of diagnostic, prognostic, or therapeutic utility.

Single-cell DNA and RNA sequencing reveals the dynamics of intra-tumor heterogeneity in a colorectal cancer model

BACKGROUND

Intra-tumor heterogeneity (ITH) encompasses cellular differences in tumors and is related to clinical outcomes such as drug resistance. However, little is known about the dynamics of ITH, owing to the lack of time-series analysis at the single-cell level. Mouse models that recapitulate cancer development are useful for controlled serial time sampling.

RESULTS

We performed single-cell exome and transcriptome sequencing of 200 cells to investigate how ITH is generated in a mouse colorectal cancer model. In the model, a single normal intestinal cell is grown into organoids that mimic the intestinal crypt structure. Upon RNAi-mediated downregulation of a tumor suppressor gene APC, the transduced organoids were serially transplanted into mice to allow exposure to in vivo microenvironments, which play relevant roles in cancer development. The ITH of the transcriptome increased after the transplantation, while that of the exome decreased. Mutations generated during organoid culture did not greatly change at the bulk-cell level upon the transplantation. The RNA ITH increase was due to the emergence of new transcriptional subpopulations. In contrast to the initial cells expressing mesenchymal-marker genes, new subpopulations repressed these genes after the transplantation. Analyses of colorectal cancer data from The Cancer Genome Atlas revealed a high proportion of metastatic cases in human subjects with expression patterns similar to the new cell subpopulations in mouse. These results suggest that the birth of transcriptional subpopulations may be a key for adaptation to drastic micro-environmental changes when cancer cells have sufficient genetic alterations at later tumor stages.

CONCLUSIONS

This study revealed an evolutionary dynamics of single-cell RNA and DNA heterogeneity in tumor progression, giving insights into the mesenchymal-epithelial transformation of tumor cells at metastasis in colorectal cancer.

Extracellular Matrices and Cancer-Associated Fibroblasts: Targets for Cancer Diagnosis and Therapy?

Solid cancer progression is dictated by neoplastic cell features and pro-tumoral crosstalks with their microenvironment. Stroma modifications, such as fibroblast activation into cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM) remodeling, are now recognized as critical events for cancer progression and as potential therapeutic or diagnostic targets. The recent appreciation of the key, complex and multiple roles of the ECM in cancer and of the CAF diversity, has revolutionized the field and raised innovative but challenging questions. Here, we rapidly present CAF heterogeneity in link with their specific ECM remodeling features observed in cancer, before developing each of the impacts of such ECM modifications on tumor progression (survival, angiogenesis, pre-metastatic niche, chemoresistance, etc.), and on patient prognosis. Finally, based on preclinical studies and recent results obtained from clinical trials, we highlight key mechanisms or proteins that are, or may be, used as potential therapeutic or diagnostic targets, and we report and discuss benefits, disappointments, or even failures, of recently reported stroma-targeting strategies.

Chemopreventive and Anti-tumor Potential of Natural Products in Oral Cancer

Oral cancer (OC) is a multifactorial disease caused by isolated or combined risk factors related to tobacco, alcohol consumption, and human papillomavirus infection. It is an aggressive pathology with a low five-year survival rate after surgery, chemotherapy, and/or radiotherapy, frequently associated with severe side effects. Drugs with the highest anti-tumor effect are obtained from natural products with diverse biological and molecular activities and potential chemopreventive and anticancer properties. This review summarizes the natural products reported to have the chemopreventive and anti-tumor potential for OC treatment, showing that several of these compounds are promising candidates as chemopreventive agents, and those with the highest anti-tumor potential induce apoptosis and inhibit proliferation and metastasis-related processes. For this reason, natural products have the potential to be important preventive and therapeutic options for OC in the future.

Metalloproteinases in Ovarian Cancer

Proteases play a crucial role in the progression and metastasis of ovarian cancer. Pericellular protein degradation and fragmentation along with remodeling of the extracellular matrix (ECM) is accomplished by numerous proteases that are present in the ovarian tumor microenvironment. Several proteolytic processes have been linked to cancer progression, particularly those facilitated by the matrix metalloproteinase (MMP) family. These proteases have been linked to enhanced migratory ability, extracellular matrix breakdown, and development of support systems for tumors. Several studies have reported the direct involvement of MMPs with ovarian cancer, as well as their mechanisms of action in the tumor microenvironment. MMPs play a key role in upregulating transcription factors, as well as the breakdown of structural proteins like collagen. Proteolytic mechanisms have been shown to enhance the ability of ovarian cancer cells to migrate and adhere to secondary sites allowing for efficient metastasis. Furthermore, angiogenesis for tumor growth and development of metastatic implants is influenced by upregulation of certain proteases, including MMPs. While proteases are produced normally in vivo, they can be upregulated by cancer-associated mutations, tumor-microenvironment interaction, stress-induced catecholamine production, and age-related pathologies. This review outlines the important role of proteases throughout ovarian cancer progression and metastasis.

Bile salt-dependent lipase promotes the barrier integrity of Caco-2 cells by activating Wnt/β-catenin signaling via LRP6 receptor

Bile salt-dependent lipase (BSDL) within intestinal lumen can be endocytosed by enterocytes and support the intestinal barrier function. However, the epithelial-supporting effect of this protein has not been verified in a human cell line and neither the direct signaling pathway nor the function of endocytosis in this process has been clearly identified. We sought to investigate the signaling pathway and the membrane receptor through which BSDL might exert these effects using intestinal epithelial cells. Caco-2 cells were treated with recombinant BSDL, and the barrier function, cell proliferation, and activation of the Wnt signaling pathway were assessed. The effect of Wnt signaling activation induced by BSDL and BSDL endocytosis was investigated in LRP6-silenced and non-silenced cells. Moreover, caveolae- and clathrin-dependent endocytosis inhibitors were also applied respectively to analyze their effects on Wnt signaling activation induced by BSDL. BSDL treatment increased the barrier function but not proliferation of Caco-2 cells. It also induced β-catenin nuclear translocation and activated Wnt target gene transcription. Moreover, in the Wnt pathway, BSDL increased the levels of non-phosphorylated-β-catenin (Ser33/37/Thr41) and phosphorylated-β-catenin (Ser552). Notably, the silencing of LRP6 expression impaired BSDL endocytosis and decreased BSDL-induced β-catenin nuclear translocation. The inhibition of BSDL endocytosis induced by caveolae-mediated endocytosis inhibitor was stronger than that by clathrin-mediated endocytosis inhibitor, and the Wnt signaling activation associated with its endocytosis was also most likely caveolae-dependent. Our findings suggested that LRP6, a canonical Wnt pathway co-receptor, can mediate BSDL endocytosis and then activate Wnt signaling in Caco-2 cells.

Transcriptional inhibition by CDK7/9 inhibitor SNS-032 abrogates oncogene addiction and reduces liver metastasis in uveal melanoma

Background

Life of patients with uveal melanoma (UM) is largely threatened by liver metastasis. Little is known about the drivers of liver organotropic metastasis in UM. The elevated activity of transcription of oncogenes is presumably to drive aspects of tumors. We hypothesized that inhibition of transcription by cyclin-dependent kinase 7/9 (CDK7/9) inhibitor SNS-032 diminished liver metastasis by abrogating the putative oncogenes in charge of colonization, stemness, cell motility of UM cells in host liver microenvironment.

Methods

The effects of SNS-032 on the expression of the relevant oncogenes were examined by qRT-PCR and Western blotting analysis. Proliferative activity, frequency of CSCs and liver metastasis were evaluated by using NOD-SCID mouse xenograft model and NOG mouse model, respectively.

Results

The results showed that CDK7/9 were highly expressed in UM cells, and SNS-032 significantly suppressed the cellular proliferation, induced apoptosis, and inhibited the outgrowth of xenografted UM cells and PDX tumors in NOD-SCID mice, repressed the cancer stem-like cell (CSC) properties through transcriptional inhibition of stemness-related protein Krüppel-like factor 4 (KLF4), inhibited the invasive phonotypes of UM cells through matrix metalloproteinase 9 (MMP9). Mechanistically, SNS-032 repressed the c-Myc-dependent transcription of RhoA gene, and thereby lowered the RhoA GTPase activity and actin polymerization, and subsequently inhibited cell motility and liver metastasis.

Conclusions

In conclusion, we validate a set of transcription factors which confer metastatic traits (e.g., KLF4 for CSCs, c-Myc for cell motility) in UM cells. Our results identify SNS-032 as a promising therapeutic agent, and warrant a clinical trial in patients with metastatic UM.

Identification of matrix metalloproteinase-2 and -9 activities within the intestinal mucosa of dogs with chronic enteropathies

BACKGROUND

Matrix metalloproteinases (MMPs) 2 and 9 are zinc- and calcium-dependent endopeptidases involved in the breakdown and reconstitution of extracellular matrix under both physiological and pathological conditions. Mucosal MMP-2 and -9 activities have been reported to be upregulated in the intestine of humans with inflammatory bowel disease (IBD), and in animal models of IBD. However, their involvement in the pathogenesis of canine chronic enteropathies (CE) is unknown. This study investigated mucosal pro- and active MMP-2 and -9 activities in dogs with CE and healthy dogs using gelatin zymography, and also to determine the association of their activities in dogs with CE with the canine IBD activity index (CIBDAI), histopathologic findings, the clinical outcome, and hypoalbuminemia. Intestinal mucosal samples from duodenum, ileum, colon, and cecum were collected from 40 dogs with CE and 18 healthy Beagle dogs.

RESULTS

In dogs with CE, the number of samples positive for mucosal pro- and active MMP-2 was significantly higher in the duodenum (P < 0.0001 and P = 0.011, respectively), ileum (P = 0.002 and P = 0.018, respectively), and colon (P < 0.0001 and P = 0.002, respectively), compared with healthy controls. Mucosal pro-MMP-9-positive samples in the duodenum and colon were significantly more frequent in dogs with CE than in healthy dogs (P = 0.0004 and P = 0.001, respectively). Despite the presence of mucosal samples positive for active MMP-9 in the intestinal segments of dogs with CE, the difference compared to healthy controls did not reach statistical significance. None of the intestinal mucosal samples in healthy dogs showed gelatinolytic activity corresponding to the control bands of active MMP-2 and -9. Mucosal active MMP-9 activities displayed a significant positive association with the severity of neutrophil infiltration in the duodenum (P = 00.040), eosinophils in the cecum (P = 00.037), and the CIBDAI score for ileum samples (P = 0.023). There was no significant association of pro- and active MMP-2 and -9 levels with the clinical outcome or hypoalbuminemia.

CONCLUSIONS

This study is the first to demonstrate upregulation of mucosal pro- and active MMP-2 and pro-MMP-9 in the intestine of dogs with CE compared to healthy dogs. The results provide supporting evidence for the possible involvement of MMP-2 and -9 in the pathogenesis of canine CE.

DNA copy number alterations, gene expression changes and disease-free survival in patients with colorectal cancer: a 10 year follow-up

BACKGROUND

DNA copy number alterations (CNAs) and gene expression changes have amply been encountered in colorectal cancers (CRCs), but the extent at which CNAs affect gene expression, as well as their relevance for tumor development, are still poorly defined. Here we aimed at assessing the clinical relevance of these parameters in a 10 year follow-up study.

METHODS

Tumors and normal adjacent colon mucosa, obtained at primary surgery from 21 CRC patients, were subjected to (i) high-resolution array CGH (a-CGH) for the detection of CNAs and (ii) microarray-based transcriptome profiling for the detection of gene expression (GE) changes. Correlations between these genomic and transcriptomic changes and their associations with clinical and histopathological parameters were assessed with the aim to identify molecular signatures associated with disease-free survival of the CRC patients during a 10 year follow-up.

RESULTS

DNA copy number gains were frequently detected in chromosomes 7, 8q, 13, 19, 20q and X, whereas DNA copy number losses were frequently detected in chromosomes 1p, 4, 8p, 15, 17p, 18, 19 and 22q. None of these alterations were observed in all samples. In addition, we found that 2,498 genes were up- and that 1,094 genes were down-regulated in the tumor samples compared to their corresponding normal mucosa (p < 0.01). The expression of 65 genes was found to be significantly associated with prognosis (p < 0.01). Specifically, we found that up-regulation of the IL17RA, IGF2BP2 and ABCC2 genes, and of genes acting in the mTOR and cytokine receptor pathways, were strongly associated with a poor survival. Subsequent integrated analyses revealed that increased expression levels of the MMP9, BMP7, UBE2C, I-CAM, NOTCH3, NOTCH1, PTGES2, HMGB1 and ERBB3 genes were associated with copy number gains, whereas decreased expression levels of the MUC1, E2F2, HRAS and SIRT3 genes were associated with copy number losses. Pathways related to cell cycle progression, eicosanoid metabolism, and TGF-β and apoptosis signaling, were found to be most significantly affected.

CONCLUSIONS

Our results suggest that CNAs in CRC tumor tissues are associated with concomitant changes in the expression of cancer-related genes. In other genes epigenetic mechanism may be at work. Up-regulation of the IL17RA, IGF2BP2 and ABCC2 genes, and of genes acting in the mTOR and cytokine receptor pathways, appear to be associated with a poor survival. These alterations may, in addition to Dukes' staging, be employed as new prognostic biomarkers for the prediction of clinical outcome in CRC patients.

MMP-TIMP interactions in cancer invasion: An evolutionary game-theoretical framework

One of the main steps in solid cancers to invade surrounding tissues is degradation of tissue barriers in the extracellular matrix. This operation that leads to initiate, angiogenesis and metastasis to other organs, is essentially consequence of collapsing dynamic balance between matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP). In this work, we model the MMP-TIMP interaction in both normal tissue and invasive cancer using evolutionary game theory. Our model explains how invasive cancer cells get the upper hand in MMP-TIMP imbalance scenarios. We investigate dynamics of them over time and discuss stable and nonstable states in the population. Numerical simulations presented here provide the identification of key genotypic features in the tumor invasion and a natural description for phenotypic variability. The simulation results are consistent with the experimental results in vitro observations presented in medical literature. Finally, by the provided results the necessary conditions to inhibit cancer invasion or prolong its course are explained. In this way, two therapeutic approaches with respect to how they could meet the required conditions are considered.

Cell polarity signaling in the plasticity of cancer cell invasiveness

Apico-basal polarity is typical of cells present in differentiated epithelium while front-rear polarity develops in motile cells. In cancer development, the transition from epithelial to migratory polarity may be seen as the hallmark of cancer progression to an invasive and metastatic disease. Despite the morphological and functional dissimilarity, both epithelial and migratory polarity are controlled by a common set of polarity complexes Par, Scribble and Crumbs, phosphoinositides, and small Rho GTPases Rac, Rho and Cdc42. In epithelial tissues, their mutual interplay ensures apico-basal and planar cell polarity. Accordingly, altered functions of these polarity determinants lead to disrupted cell-cell adhesions, cytoskeleton rearrangements and overall loss of epithelial homeostasis. Polarity proteins are further engaged in diverse interactions that promote the establishment of front-rear polarity, and they help cancer cells to adopt different invasion modes. Invading cancer cells can employ either the collective, mesenchymal or amoeboid invasion modes or actively switch between them and gain intermediate phenotypes. Elucidation of the role of polarity proteins during these invasion modes and the associated transitions is a necessary step towards understanding the complex problem of metastasis. In this review we summarize the current knowledge of the role of cell polarity signaling in the plasticity of cancer cell invasiveness.

Monocytes increase human cardiac myofibroblast-mediated extracellular matrix remodeling through TGF-β1

Following myocardial infarction (MI), cardiac myofibroblasts remodel the extracellular matrix (ECM), preventing mechanical complications. However, prolonged myofibroblast activity leads to dysregulation of the ECM, maladaptive remodeling, fibrosis, and heart failure (HF). Chronic inflammation is believed to drive persistent myofibroblast activity; however, the mechanisms are unclear. We assessed the influence of peripheral blood monocytes on human cardiac myofibroblast activity in a three-dimensional (3D) ECM microenvironment. Human cardiac myofibroblasts isolated from surgical biopsies of the right atrium and left ventricle were seeded into 3D collagen matrices. Peripheral blood monocytes were isolated from healthy human donors and cocultured with myofibroblasts. Monocytes increased myofibroblast activity measured by collagen gel contraction (baseline: 57.6 ± 5.9% vs. coculture: 65.2 ± 7.1% contraction; P < 0.01) and increased local ECM remodeling quantified by confocal microscopy. Under coculture conditions that allow indirect cellular interaction via paracrine factors but prevent direct cell-cell contact, monocytes had minimal effects on myofibroblast activity (17.9 ± 11.1% vs. 6.4 ± 7.0% increase, respectively; P < 0.01). When cells were cultured under direct contact conditions, multiplex analysis of the coculture media revealed an increase in the paracrine factors TGF-β1 and matrix metalloproteinase 9 compared with baseline (122.9 ± 10.1 pg/ml and 3,496.0 ± 190.4 pg/ml, respectively, vs. 21.5 ± 16.3 pg/ml and 183.3 ± 43.9 pg/ml; P < 0.001). TGF-β blockade abolished the monocyte-induced increase in cardiac myofibroblast activity. These data suggest that direct cell-cell interaction between monocytes and cardiac myofibroblasts stimulates TGF-β-mediated myofibroblast activity and increases remodeling of local matrix. Peripheral blood monocyte interaction with human cardiac myofibroblasts stimulates myofibroblast activity through release of TGF-β1. These data implicate inflammation as a potential driver of cardiac fibrosis.

GnRH-(1-5) activates matrix metallopeptidase-9 to release epidermal growth factor and promote cellular invasion

In the extracellular space, the gonadotropin-releasing hormone (GnRH) is metabolized by the zinc metalloendopeptidase EC3.4.24.15 (EP24.15) to form the pentapeptide, GnRH-(1-5). GnRH-(1-5) diverges in function and mechanism of action from GnRH in the brain and periphery. GnRH-(1-5) acts on the orphan G protein-coupled receptor 101 (GPR101) to sequentially stimulate epidermal growth factor (EGF) release, phosphorylate the EGF receptor (EGFR), and facilitate cellular migration. These GnRH-(1-5) actions are dependent on matrix metallopeptidase (MMP) activity. Here, we demonstrated that these GnRH-(1-5) effects are dependent on increased MMP-9 enzymatic activity in the Ishikawa and ECC-1 cell lines. Furthermore, the effects of GnRH-(1-5) mediated by GPR101 and the subsequent increase in MMP-9 enzymatic activity lead to an increase in cellular invasion. These results suggest that GnRH-(1-5) and GPR101 regulation of MMP-9 may have physiological relevance in the metastatic potential of endometrial cancer cells.

Spraying quantum dot conjugates in the colon of live animals enabled rapid and multiplex cancer diagnosis using endoscopy

The detection of colon cancer using endoscopy is widely used, but the interpretation of the diagnosis is based on the clinician's naked eye. This is subjective and can lead to false detection. Here we developed a rapid and accurate molecular fluorescence imaging technique using antibody-coated quantum dots (Ab-QDs) sprayed and washed simultaneously on colon tumor tissues inside live animals, subsequently excited and imaged by endoscopy. QDs were conjugated to matrix metalloproteinases (MMP) 9, MMP 14, or carcinoembryonic antigen (CEA) Abs with zwitterionic surface coating to reduce nonspecific bindings. The Ab-QD probes can diagnose tumors on sectioned mouse tissues, fresh mouse colons stained ex vivo and also in vivo as well as fresh human colon adenoma tissues in 30 min and can be imaged with a depth of 100 μm. The probes successfully detected not only cancers that are readily discernible by bare eyes but also hyperplasia and adenoma regions. Sum and cross signal operations provided postprocessed images that can show complementary information or regions of high priority. This multiplexed quantum dot, spray-and-wash, and endoscopy approach provides a significant advantage for detecting small or flat tumors that may be missed by conventional endoscopic examinations and bestows a strategy for the improvement of cancer diagnosis.

Metastasis review: from bench to bedside

Cancer is the final result of uninhibited cell growth that involves an enormous group of associated diseases. One major aspect of cancer is when cells attack adjacent components of the body and spread to other organs, named metastasis, which is the major cause of cancer-related mortality. In developing this process, metastatic cells must successfully negotiate a series of complex steps, including dissociation, invasion, intravasation, extravasation, and dormancy regulated by various signaling pathways. In this review, we will focus on the recent studies and collect a comprehensive encyclopedia in molecular basis of metastasis, and then we will discuss some new potential therapeutics which target the metastasis pathways. Understanding the new aspects on molecular mechanisms and signaling pathways controlling tumor cell metastasis is critical for the development of therapeutic strategies for cancer patients that would be valuable for researchers in both fields of molecular and clinical oncology.

Identification of matrix metalloproteinase-2 and -9 activities within intestinal mucosa of clinically healthy beagle dogs

Matrix metalloproteinases (MMPs) 2 and 9 are zinc-dependent endopeptidases that contribute to the control of breakdown and reconstitution of extracellular matrix under both normal and pathological conditions. The main objective of this study was to identify the presence of MMP-2 and -9 in the mucosa of the small and large intestines of clinically healthy beagle dogs using gelatin zymography technique. Intestinal mucosa samples from four different parts of the intestine (duodenum, jejunum, ileum and colon) were taken from 12 healthy laboratory beagle dogs and examined histologically. Based on WSAVA histology standards, recorded findings of all samples were considered insignificant. Pro-MMP-2 and -9 activities were found in 17/48 (35%) and 25/48 (52%) of the samples, respectively. Among four different parts of the intestine of 12 dogs, the ileum had the highest positivity rates of 7/12 (58.3%) and 8/12 (66.7%) for pro-MMP-2 and -9 activities, respectively. However, statistical analysis showed no significant difference of pro-MMP-2 and -9 activities between the separate parts of the intestine (P>0.05). None of the intestinal samples showed gelatinolytic activity corresponding to the control bands of active MMP-2 and MMP-9. This study showed that pro-MMP-2 and -9 could be detected in the intestinal mucosa of healthy dogs using zymography, which seems to be a useful tool to evaluate the role of MMP-2 and -9 in the pathogenesis of canine chronic enteropathies, including inflammatory bowel diseases.

Combined therapeutic effects of vinblastine and Astragalus saponins in human colon cancer cells and tumor xenograft via inhibition of tumor growth and proangiogenic factors

Our previous study had demonstrated that Astragalus saponins (AST) could reduce the side effects of orthodox chemotherapeutic drugs, while concurrently promote antitumor activity. In the present study, we attempted to investigate the potential synergistic anticarcinogenic effects of AST and a vinca alkaloid vinblastine (VBL). Reduced expression of key proangiogenic and metastatic factors including VEGF, bFGF, metalloproteinase (MMP)-2, and MMP-9 was detected in VBL-treated colon cancer cells, with further downregulation by combined VBL/AST treatment. Subsequently, VBL or AST decreased LoVo cell invasiveness, with further reduction when the drugs were cotreated. Significant growth inhibition and cell cycle arrest at G2/M phase were achieved by either drug treatment with apparent synergistic effects. VBL-induced apoptosis was confirmed but found to be unrelated to induction of the novel apoptotic protein NSAID-activated gene 1. In vivo study in tumor xenograft indicates that combined VBL/AST treatment resulted in sustained regression of tumor growth, with attenuation of the neutropenic and anemic effects of VBL. In addition, downregulation of proangiogenic and proliferative factors was also visualized, with boosting effect by combined drug treatment. These findings have provided evidence that AST combined with adjuvant chemotherapeutics like VBL could alleviate cancer development through diversified modes of action, including the regulation of angiogenesis.

The role of cyclic nucleotide signaling pathways in cancer: targets for prevention and treatment

For more than four decades, the cyclic nucleotides cyclic AMP (cAMP) and cyclic GMP (cGMP) have been recognized as important signaling molecules within cells. Under normal physiological conditions, cyclic nucleotides regulate a myriad of biological processes such as cell growth and adhesion, energy homeostasis, neuronal signaling, and muscle relaxation. In addition, altered cyclic nucleotide signaling has been observed in a number of pathophysiological conditions, including cancer. While the distinct molecular alterations responsible for these effects vary depending on the specific cancer type, several studies have demonstrated that activation of cyclic nucleotide signaling through one of three mechanisms-induction of cyclic nucleotide synthesis, inhibition of cyclic nucleotide degradation, or activation of cyclic nucleotide receptors-is sufficient to inhibit proliferation and activate apoptosis in many types of cancer cells. These findings suggest that targeting cyclic nucleotide signaling can provide a strategy for the discovery of novel agents for the prevention and/or treatment of selected cancers.

Clinicopathological and biological significance of cripto overexpression in human colon cancer

AIM: To assess the clinicopathological and biological significance of cripto in human colorectal cancer.

METHODS: Real-time reverse-transcription polymerase chain reaction (PCR) was used to examine cripto mRNA levels in primary colon cancer and normal colon tissues as well as normal and metastatic lymph nodes from colon cancers. Human colon cancer LS-174T cells were transfected with cripto small interfering RNA (siRNA), and mRNA and protein levels were evaluated using real-time PCR and western blot analysis, respectively. The growth of cancer cells was evaluated using the MTT assay and colony formation in soft agar. Invasion was examined using a Transwell assay, and the expressions of matrix metalloproteinase (MMP)-7 and MMP-9 were determined using western blot assay.

RESULTS: Cripto was significantly overexpressed in primary colon cancer and metastatic lymph nodes. Silencing cripto gene expression with cripto siRNA resulted in a significant decrease in colony formation in soft agar in the colon cancer cell line LS-174T. Cripto siRNA treatment decreased the migration and invasion capabilities of the colon cancer cell line LS-174T in vitro. Furthermore, cripto siRNA treatment inhibited the expression of matrix MMP-7 and MMP-9.

CONCLUSION: The results provide evidence that cripto siRNA could be an effective approach for the inhibition of cancer cell invasion and migration and thus has potential for use in devising novel preventive and therapeutic strategies for colon cancer metastasis.

Pre-Treatment of platinum resistant ovarian cancer cells with an MMP-9/MMP-2 inhibitor prior to cisplatin enhances cytotoxicity as determined by high content screening

Platinum resistance is a major cause of treatment failure in ovarian cancer. We previously identified matrix metalloproteinase 9 (MMP-9) as a potential therapeutic target of chemoresistant disease. A2780cis (cisplatin-resistant) and A2780 (cisplatin-sensitive) ovarian carcinoma cell lines were used. The cytotoxic effect of MMP-9/MMP-2 inhibitor, (2R)-2-[(4-Biphenylsulfonyl) amino]-3 phenylpropionic acid (C21H19NO4S) alone or in combination with cisplatin was determined using high content screening. Protein expression was examined using immunohistochemistry and ELISA. Co-incubation of cisplatin and an MMP-9/MMP-2 inhibitor, (2R)-2-[(4-Biphenylsulfonyl) amino]-3 phenylpropionic acid (C21H19NO4S) resulted in significantly greater cytotoxicity as compared to either treatment alone in a cisplatin resistant MMP-9 overexpressing cell line; A2780cis. In addition, pre-incubating with MMP-9i prior to cisplatin further enhances the cytotoxic effect. No significant difference was observed in MMP-9 protein in tissue but a trend towards increased MMP-9 was observed in recurrent serum. We propose that MMP-9/MMP-2i may be utilized in the treatment of recurrent/chemoresistant ovarian cancers that overexpress MMP-9 mRNA but its role in vivo remains to be evaluated.

Novel anti-angiogenic effects of formononetin in human colon cancer cells and tumor xenograft

Formononetin is a novel herbal isoflavonoid isolated from Astragalus membranaceus, a medicinal plant that possesses antitumorigenic properties. Our previous findings demonstrated that formononetin initiates growth-inhibitory and pro-apoptotic activities in human colon cancer cells. In the present study, we aimed to further examine the potential of formononetin in controlling angiogenesis and tumor cell invasiveness in human colon cancer cells and tumor xenografts. The results showed that formononetin downregulated the expression of the key pro-angiogenic factors, including vascular endothelial growth factor (VEGF) and matrix metalloproteinases. We also discovered that the invasiveness of metastatic colon cancer cells was alleviated following drug treatment. The potential anti-angiogenic effect of formononetin was examined in nude mouse xenografts. The tumor size and the number of proliferating cells were reduced in the tumor tissues obtained from the formononetin-treated group. The serum VEGF level was also reduced in the drug-treated animals when compared to the controls. These findings suggest that formononetin inhibits angiogenesis and tumor cell invasion, and thus support its use in the treatment of advanced and metastatic colon cancers.

Characterization of biological responses of colorectal cancer cells to anticancer regimens

PURPOSE

Identification of subgroups of patients who differ in their response to treatment could help to establish which of the best available chemotherapeutic options are best, based on biological activity. In metastatic colorectal cancer (CRC), novel molecular-targeted agents that act on pathways that regulate cell growth, the cell cycle, apoptosis, angiogenesis, and invasion are being developed. Here, we employed an in vitro chemosensitivity assay to evaluate the biological efficacy of conventional monotherapies and combination chemotherapy with targeted drugs.

METHODS

The chemosensitivities of 12 CRC cell lines to the established regimens FOLFOX (5-fluorouracil [5-FU] + leucovorin + oxaliplatin) and FOLFIRI (5-FU + leucovorin + irinotecan) and to therapy with these regimens in combination with the biologically targeted drugs bevacizumab or cetuximab were comparatively evaluated for their effects on apoptotic and autophagic cell death processes, angiogenesis, and invasion.

RESULTS

Each of the chemotherapeutic regimens promoted apoptotic cell death and invasion. All drug regimens caused significantly greater apoptotic cell death with activation of caspase-3 in SW480 cells compared to other cells, effects that were associated with a remarkable reduction in matrix metalloproteinase-9 activity. The FOLFOX regimen more effectively promoted apoptotic cell death, angiogenesis, and invasion than the FOLFIRI regimen. Combination therapy with FOLFOX/FOLFIRI regimen and bevacizumab produced a moderate angiogenesis-blocking effect in most cell lines.

CONCLUSION

The results validate our in vitro chemosensitivity assay, and suggest that it may be applied to help determine adequate regimens in individual CRC patients based on the biological characteristics of their tumors.

Expression and biological relationship of vascular endothelial growth factor-A and matrix metalloproteinase-9 in gastric carcinoma

Protein expression of vascular endothelial growth factor A (VEGF-A) and matrix metalloproteinase 9 (MMP-9) was studied in gastric carcinoma patients in relation to clinicopathological characteristics and prognosis. Fifty-four samples of gastric carcinoma tissue and 15 samples of adjacent normal gastric mucosal tissue were examined immunohistochemically. Expression rates of VEGF-A (66.7%) and MMP-9 (63.0%) in carcinoma tissue were significantly higher than in normal tissue (6.7% for both proteins). VEGF-A and MMP9 expression was associated with tumour size, invasion depth, lymph node metastasis, degree of histological differentiation and pathological stage, but not age or sex. VEGF-A expression was positively correlated with that of MMP-9. Expression of VEGF-A and MMP-9 were each inversely correlated with 5-year survival. VEGF-A and MMP-9 were overexpressed in tumours compared with normal tissue; they may act together to increase carcinogenesis and the progression, invasion and metastasis of gastric carcinoma, and could be used as biomarkers for the prognosis of gastric carcinoma.

Matrix metalloproteinases in tumorigenesis: an evolving paradigm

Proteases are crucial for development, tissue remodeling, and tumorigenesis. Matrix metalloproteinases (MMPs) family, in particular, consists of more than 20 members with unique substrates and diverse function. The expression and activity of MMPs in a variety of human cancers have been intensively studied. MMPs have well-recognized roles in the late stage of tumor progression, invasion, and metastasis. However, increasing evidence demonstrates that MMPs are involved earlier in tumorigenesis, e.g., in malignant transformation, angiogenesis, and tumor growth both at the primary and metastatic sites. Recent studies also suggest that MMPs play complex roles in tumor progression. While most MMPs promote tumor progression, some of them may protect the host against tumorigenesis in a context-dependent manner. MMPs have been chosen as promising targets for cancer therapy on the basis of their aberrant up-regulation in malignant tumors and their ability to promote cancer metastasis. Although preclinical studies testing the efficacy of MMP suppression in tumor models were so encouraging, the results of clinical trials in cancer patients have been rather disappointing. Here, we review the complex roles of MMPs and their endogenous inhibitors such as tissue inhibitors of metalloproteinase in tumorigenesis and strategies in suppressing MMPs.

Neutrophil gelatinase-associated lipocalin (NGAL) and matrix metalloproteinase-9 (MMP-9) prognostic value in stage I colorectal carcinoma

The expression of neutrophil gelatinase-associated lipocalin (NGAL) has been suggested to behave like a negative prognostic marker in stage I colorectal carcinoma. In the aim of clarifying whether its association with adverse outcome may descend from NGAL's ability to regulate matrix metallo-proteinase-9 (MMP-9), we analyzed the correlation, prognostic value, and association with neo-angiogenesis of NGAL and MMP-9 immunohistochemical expression in a series of stage I colorectal carcinomas. A variable NGAL immunoexpression was demonstrated in 17 of the 48 analyzed cases with a significantly higher frequency of positive cases among patients showing disease progression. NGAL expression was also positively correlated with VEGF expression detected in the same cases. MMP-9 immunostaining was present in the cytoplasm of the neoplastic cells in 30 cases; no significant correlations were evidenced with NGAL expression, as well as with the various clinico-pathological parameters or with progression of the colorectal carcinomas. By contrast, NGAL expression was confirmed as a significant independent negative prognostic marker related to a shorter disease-free survival in stage I colorectal carcinoma. Our preliminary results suggest that the association of NGAL with poor outcome might be independent from MMP-9 regulation, thus highlighting its prognostic value in this neoplasia. If our findings are confirmed in further analyses, NGAL assessment might be used in order to select those patients with a higher progression risk and to submit them to adjuvant therapies useful to prevent adverse outcome.

Matrix metalloproteinase-9 is a prognostic marker to predict survival of patients who underwent surgery due to rectal carcinoma

Common prognostic factors do not fully predict clinical outcomes in colorectal cancer, one of the most common malignancies in developed countries. Therefore, biological prognostic markers are under investigation. We investigated the prognostic value of expression of matrix metalloproteinases (MMP-2 and MMP-9) and their inhibitors (TIMP-2 and TIMP-3) in rectal carcinoma to predict survival of the patients. Retrospective analysis of clinicopathological findings of 64 patients who underwent rectal resection due to carcinoma and were followed-up from 2 to 96 months (median 48) was performed. Semi-quantitative scoring was used to assess the expression levels of MMP-2, MMP-9, TIMP-2 and TIMP-3 in rectal carcinoma. During the follow-up, 28 patients died. The deceased patients demonstrated significantly higher expression of MMP-9 and lower expression of TIMP-3 in parenchyma of carcinoma and lower expression of TIMP-2 in stroma of carcinoma, compared to survivors. Moreover, the deceased patients were associated with advanced tumor, metastases in lymph nodes and distant metastases. According to univariate analysis longer survival was predicted by lower expression of MMP-9 in parenchymal cells (p = 0.03), tumor size (early tumor) (p = 0.026), absence of metastases in lymph nodes (p = 0.02) or distant metastases (p = 0.04). Multivariate analysis revealed that metastases in lymph nodes, higher expression of MMP-9 in parenchyma, and lower expression of MMP-9 in stromal cells significantly increased mortality. Expression of MMP-9 in rectal carcinoma is a prognostic marker for overall survival. It is important to identify the origin of MMP-9 to predict better overall survival of the patients.

Expression of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) by colorectal cancer cells and adjacent stroma cells--associations with histopathology and patients outcome

AIM

To elucidate cellular features accountable for colorectal cancers' (CRC) capability to invade normal tissue and to metastasize, we investigated the level of the collagenase matrix metalloproteinase 9 (MMP-9) and its physiological inhibitor tissue inhibitor of metalloproteinases 1 (TIMP-1) in cancer cells and supporting stroma cells of CRC.

METHODS

Immunoreactivity of MMP-9 and TIMP-1 by carcinoma cells, lymphocytes and fibroblasts in archival specimens of paraffin-embedded primary tumours were retrospectively associated with outcome in 340 consecutive patients completely resected for CRC stages II-IV and subsequently treated with adjuvant 5-fluorouracil.

RESULTS

Expression of MMP-9 by carcinoma cells was demonstrated in 9% of specimens without association to recurrence free survival (RFS) (HR = 1.0; 95% CI: 0.6-1.8; P = 0.9) or overall survival (OS) (HR = 0.9; 95% CI: 0.5-1.6; P = 0.6). TIMP-1 expression by carcinoma cells, which appeared in 64% of the specimens, was inversely related with RFS (HR = 1.3; 95% CI: 0.9-1.8; P = 0.08) and OS (HR = 1.5; 95% CI: 1.1-2.1; P = 0.02). Expression of TIMP-1 by fibroblasts at the invasive border was directly related to RFS (HR = 0.7; 95% CI: 0.6-0.9; P = 0.02) and OS (HR = 0.7; 95% CI: 0.6-1.0; P = 0.05). Expression of MMP-9 by lymphocytes correlated significantly with the degree of peritumoural inflammation (P = 0.02) but not with RFS (HR = .9; 95% CI: 0.7-1.1; P = 0.2) or OS (HR = 0.8; 95% CI: 0.7-1.0; P = 0.07).

CONCLUSION

TIMP-1 in cancer cells is associated with poor prognosis independent of its function as inhibitor of MMP-9. MMP-9 and TIMP-1 are important mediators of the host-cancer cell interaction in the tumour microenvironment with significant influence on the histopathology and on prognosis of CRC.

Near-infrared fluorescence imaging using a protease-specific probe for the detection of colon tumors

BACKGROUND/AIMS

Early tumor detection is crucial for the prevention of colon cancer. Near-infrared fluorescence (NIRF) imaging using a target-activatable probe may permit earlier disease detection. Matrix metalloproteinases (MMPs) participate in tumorigenesis and tumor growth. The aim of this study was to determine whether NIRF imaging using an MMP-activatable probe can detect colon tumors at early stages.

METHODS

WE UTILIZED TWO MURINE COLON CANCER MODELS: a sporadic colon cancer model induced by azoxymethane (AOM), and a colitis-associated cancer model induced by a combination of AOM and dextran sodium sulfate (DSS). Colonic lesions were analyzed by histologic examination, Western blotting, immunohistochemical staining, and NIRF imaging using an MMP-activatable probe.

RESULTS

Multiple variable-sized tumors developed in both models and progressed from adenomas to adenocarcinomas over time. At the early stage of the AOM/DSS model, diffuse inflammation was observed within the tumors. MMP expression increased progressively through normal, inflammation, adenoma, and adenocarcionoma stages. NIRF signal intensities were strongly correlated with each tumor stage from adenoma to adenocarcinoma. NIRF imaging also distinguished tumors from inflamed mucosa.

CONCLUSIONS

NIRF imaging using a protease-activatable probe may be a useful tool for early tumor detection. This approach could translate to improve the endoscopic detection of colon tumors, especially in patients with inflammatory bowel disease.

Intratumoral macrophage counts correlate with tumor progression in colorectal cancer

BACKGROUND

The role of intratumoral tumor-associated macrophages (TAMs) in colorectal cancer (CRC) is not clear. We aim to examine the relationships of TAMs and the clinicopathologic features of CRC and the expression of matrix metalloproteinases (MMP)-2 and MMP-9.

METHODS

Immunohistochemical staining of CD68, MMP-2, and MMP-9 was determined in tissue samples from CRC patients. To test the biological effect of macrophages on tumor cells, cancer cells were cocultured with macrophages and function change of cancer cells were examined.

RESULTS

Intratumoral TAM count correlated with depth of invasion (P = 0.048), lymph node metastasis (P < 0.0001), and staging (P < 0.0001) of CRC. MMP-2 and MMP-9 expression was significantly associated with lymph node metastasis and staging. A significant association between intratumoral TAM counts and MMP-2 (P < 0.0001) and MMP-9 (P < 0.0001) expression was noted. When cocultured with macrophages, cancer cells increased their invasiveness and migration and elevated MMP-2 and MMP-9 secretion.

CONCLUSIONS

Intratumoral TAMs cause cancer cells to have a more aggressive behavior, and this may be due to an upregulation of tumor cell-derived MMP-2 and MMP-9. Examination of intratumoral TAMs can serve as a progressive marker for CRC patients.

Overexpression of matrix metalloproteinase 9 in tumor epithelial cells correlates with colorectal cancer metastasis

Colorectal cancer mortality largely reflects metastasis, the spread of the disease to distant organs. Matrix metalloproteinase 9 (MMP-9) is a key regulator of metastasis and a target for anticancer strategies in colon cancer. Here, the overexpression of MMP-9 in pure tumor epithelial, but nor stromal, cell populations was associated with metastatic progression of colorectal cancer, as defined by reverse transcriptase-polymerase chain reaction (qRT-PCR) and confirmed by immunostaining. Thus, cancer cell MMP-9 represents a novel, selective prognostic and predictive factor that may be exploited for more effective disease stage stratification and therapeutic regimen selection in patients with colorectal cancer.

p38gamma MAPK cooperates with c-Jun in trans-activating matrix metalloproteinase 9

Mitogen-activated protein kinases (MAPKs) regulate gene expression through transcription factors. However, the precise mechanisms in this critical signal event are largely unknown. Here, we show that the transcription factor c-Jun is activated by p38gamma MAPK, and the activated c-Jun then recruits p38gamma as a cofactor into the matrix metalloproteinase 9 (MMP9) promoter to induce its trans-activation and cell invasion. This signaling event was initiated by hyperexpressed p38gamma that led to increased c-Jun synthesis, MMP9 transcription, and MMP9-dependent invasion through p38gamma interacting with c-Jun. p38gamma requires phosphorylation and its C terminus to bind c-Jun, whereas both c-Jun and p38gamma are required for the trans-activation of MMP9. The active p38gamma/c-Jun/MMP9 pathway also exists in human colon cancer, and there is a coupling of increased p38gamma and MMP9 expression in the primary tissues. These results reveal a new paradigm in which a MAPK acts both as an activator and a cofactor of a transcription factor to regulate gene expression leading to an invasive response.

Matrix metalloproteinase-9 functions as a tumor suppressor in colitis-associated cancer

There is a well-documented association of matrix metalloproteinase-9 (MMP-9) and receptor Notch-1 overexpression in colon cancer. We recently showed that MMP-9 is also upregulated in colitis, where it modulates tissue damage and goblet cell differentiation via proteolytic cleavage of Notch-1. In this study, we investigated whether MMP-9 is critical for colitis-associated colon cancer (CAC). Mice that are wild type (WT) or MMP-9 nullizygous (MMP-9(-/-)) were used for in vivo studies and the human enterocyte cell line Caco2-BBE was used for in vitro studies. CAC was induced in mice using an established carcinogenesis protocol that involves exposure to azoxymethane followed by treatment with dextran sodium sulfate. MMP-9(-/-) mice exhibited increased susceptibility to CAC relative to WT mice. Elevations in tumor multiplicity, size, and mortality were associated with increased proliferation and decreased apoptosis. Tumors formed in MMP-9(-/-) mice exhibited expression of p21(WAF1/Cip1) and increased expression of beta-catenin relative to WT mice. In vitro studies of MMP-9 overexpression showed increased Notch-1 activation with a reciprocal decrease in beta-catenin. Notch and beta-catenin/Wnt signaling have crucial roles in determining differentiation and carcinogenesis in gut epithelia. Despite being a mediator of proinflammatory responses in colitis, MMP-9 plays a protective role and acts as a tumor suppressor in CAC by modulating Notch-1 activation, thereby resulting in activation of p21(WAF1/Cip1) and suppression of beta-catenin.

Inhibitory effects of tanshinone II-A on invasion and metastasis of human colon carcinoma cells

AIM

To investigate the effects and possible mechanisms of tanshinone II-A, an alcohol extract of the root of Salvia miltiorrhiza Bunge, on tumor invasion and metastasis of human colon carcinoma (CRC) cells.

METHODS

The effects of tanshinone II-A on invasion and metastasis of CRC cell lines HT29 and SW480 were evaluated by in vitro and in vivo assays. Western blotting was used to investigate possible molecular mechanisms of tanshinone II-A anti-cancer actions.

RESULTS

Tanshinone II-A inhibited migration and invasion of CRC cells in a dose-dependent manner. The inhibitory effect also depended on time, with the most significant effects observed at 72 h. Tanshinone II-A also significantly inhibited in vivo metastasis of colon carcinoma SW480 cells. It inhibited in vitro and in vivo invasion and metastasis of CRC cells by reducing levels of urokinase plasminogen activator (uPA) and matrix metalloproteinases (MMP)-2 and MMP-9, and by increasing levels of tissue inhibitor of matrix metalloproteinase protein (TIMP)-1 and TIMP-2. Tanshinone II-A was also shown to suppress the nuclear factor-kappaB (NF-kappaB) signal.

CONCLUSION

Tanshinone II-A inhibited in vitro and in vivo invasion and metastasis of CRC cells. The effect resulted from changes in the levels of uPA, MMP-2, MMP-9, TIMP-1 and TIMP-2, and apparent inhibition of the NF-kappaB signal transduction pathway.

Guanylyl cyclase C prevents colon cancer metastasis by regulating tumor epithelial cell matrix metalloproteinase-9

Matrix metalloproteinase-9 (MMP-9) produced by colorectal cancer cells is a critical determinant of metastatic disease progression and an attractive target for antimetastatic strategies to reduce colon cancer mortality. Cellular signaling by cyclic GMP (cGMP) regulates MMP-9 dynamics in various cell systems, and the bacterial enterotoxin receptor guanylyl cyclase C (GCC), the principle source of cGMP in colonocytes, which is overexpressed in colorectal cancers, inhibits tumor initiation and progression in the intestine. Here, we show that ligand-dependent GCC signaling through cGMP induces functional remodeling of cancer cell MMP-9 reflected by a compartmental redistribution of this gelatinase, in which intracellular retention resulted in reciprocal extracellular depletion. Functional remodeling of MMP-9 by GCC signaling reduced the ability of colon cancer cells to degrade matrix components, organize the actin cytoskeleton to form locomotory organelles and spread, and hematogenously seed distant organs. Of significance, GCC effects on cancer cell MMP-9 prevented establishment of metastatic colonies by colorectal cancer cells in the mouse peritoneum in vivo. Because endogenous hormones for GCC are uniformly deficient in intestinal tumors, reactivation of dormant GCC signaling with exogenous administration of GCC agonists may represent a specific intervention to target MMP-9 functions in colon cancer cells. The notion that GCC-mediated regulation of cancer cell MMP-9 disrupts metastasis, in turn, underscores the unexplored utility of GCC hormone replacement therapy in the chemoprevention of colorectal cancer progression.

Matrix metalloproteinases 2, 3, 13 and their type 2 tissue inhibitor in tumors and plasma of patients with colorectal cancer

Enzyme immunoassay studies revealed increased content of matrix metalloproteinases 2, 3 and 13 in tumors compared to the adjacent histologically unchanged mucosa in 70-90% patients with colorectal cancer, while the increase in the content of type 2 metalloproteinase tissue inhibitor did not reach the level of statistic significance. Plasma concentrations of these proteins did not correlate with the corresponding values in the tumors and did not surpass the normal levels, while their decrease after removal of the primary tumor was observed only in patients with initially high levels of this parameter.

Distinct functionality of tumor cell-derived gelatinases during formation of liver metastases

The specific spatiotemporal role of the matrix metalloproteinase 2 (MMP-2) and MMP-9 (gelatinase) during metastasis is still under debate. Host cells have been described as major contributors to these MMPs during metastasis. Here, we show strong overexpression of MMP-2 and MMP-9 by tumor cells of clinical liver specimen of recurrent metachronous metastases, leading us to address the importance of tumor cell-derived MMP-2 or MMP-9 during liver metastasis. Thus far, distinction of their roles was impossible due to lack of inhibitors which can act exclusively on tumor cells or distinguish MMP-2 from MMP-9. We therefore used short hairpin RNA interference technology in the well-established syngeneic L-CI.5s lymphoma model, in which we could analyze the time course of experimental liver colonization (arrest/invasion of single tumor cells, outgrowth, and invasion within the parenchyma) in immunocompetent mice and correlate these steps with MMP-2 or MMP-9 expression levels. In parental tumor cells, MMP-9 expression closely correlated with the invasive phases of liver colonization, whereas MMP-2 expression remained unaltered. Specific knockdown of MMP-9 revealed a close correlation between invasion-dependent events and tumor cell-derived MMP-9 expression. In contrast, knockdown of MMP-2 did not significantly alter the metastatic potential of the cells but led to a marked inhibition of metastatic foci growth. These findings explain the efficacy of gelatinase-specific synthetic inhibitors on invasion and growth of tumor cells and attribute distinct functions of MMP-2 and MMP-9 to aspects of liver metastasis.

Matrix metalloproteinases 7 and 9 and their types 1 and 4 tissue inhibitors in tumors and plasma of patients with colorectal cancer

Enzyme immunoassays showed significantly elevated content of matrix metalloproteinase 7 and type 1 tissue inhibitor of metalloproteinases in tumors compared to adjacent histologically unchanged mucosa of patients with colorectal cancer; the levels of metalloproteinase 9 and type 4 tissue inhibitor of metalloproteinases were virtually the same in the tumors and mucosa. Plasma concentrations of the studied proteins did not correlate with their levels in the tumor, did not surpass the normal, and did not decease after removal of the primary tumor in the majority of patients.

Matrix metalloproteinase-9 expression in the normal mucosa-adenoma-dysplasia-adenocarcinoma sequence of the colon

It has been proposed that matrix metalloproteinases (MMPs) play a role in tumor invasion. We determined protein expression of matrix metalloproteinase-9 (MMP-9) in colorectal cancer (CRC), corresponding normal mucosa and colorectal adenomas. For confirmation of immunohistochemical results MMP-9 TaqMan RT-PCR analysis was performed. Expression of MMP-9 was determined on paraffin embedded biopsy sections by immunohistochemistry in 31 CRC patients (from cancer tissue and corresponding normal mucosa) and in 30 patients with adenoma (nine adenomas with high grade of dysplasia). MMP-9 immunostaining was determined semi-quantitatively. For Taqman RT-PCR analyses normal mucosa (n = 5), adenoma without (n = 6) and with high grade dysplasia (n = 7) and CRC (n = 10) were investigated. Statistical analysis with ANOVA, LSD test and correlation analysis were performed. P value of <0.05 was considered significant. The MMP-9 expression in CRC was significantly higher compared to adenomas or the normal mucosa (P = 0.001). Significantly higher expression of MMP-9 has been observed in adenomas with high grade dysplasia compared to other adenomas or normal colon (P < 0.001). Diffuse strong MMP-9 expression was present in tumor as well as in stromal cells. In adenoma samples, dysplastic epithelial cells showed moderate intensive cytoplasmic MMP-9 expression, with a clear-cut differentiation between dysplastic and non-dysplastic areas. Staining intensity correlated with the grade of CRC. We demonstrate a significantly higher expression of MMP-9 in adenoma with high grade dysplasia-CRC sequence as compared to normal tissue. The over-expression of MMP-9 strongly suggests its association with colorectal carcinogenesis.

The paracrine hormone hypothesis of colorectal cancer

Colorectal carcinogenesis originates in the context of dysregulated epithelial cell homeostasis, wherein hyperproliferation, hypodifferentiation, metabolic reprogramming, and mesenchymal remodeling reflect recursive mutually reinforcing mechanisms contributing to progressive genomic instability. Although genotypic and phenotypic elements characterizing the terminal integration of these pathophysiological processes defining cancer are well enumerated, events initiating, coordinating, and sustaining this hierarchical maladaptive systems evolution remain elusive for most tumors. In the intestine, guanylyl cyclase C (GCC) and its paracrine ligands organize and regulate the homeostatic integrity of the crypt-villus axis, forming a hormonal tumor suppressor signaling sequence, whose dysfunction defines the initiation of neoplastic transformation and creates a permissive niche for tumor progression.

Warm hepatic ischemia-reperfusion promotes growth of colorectal carcinoma micrometastases in mouse liver via matrix metalloproteinase-9 induction

Surgical resection remains the best treatment for colorectal metastases isolated to the liver; however, 5-year survival rates following liver resection are only 40% to 50%, with liver recurrence being a significant reason for treatment failure. The ischemia-reperfusion (I/R) injury incurred during liver surgery can lead to cellular dysfunction and elevations in proinflammatory cytokines and matrix metalloproteinases (MMP). In rodents, I/R injury to the liver has been shown to accelerate the outgrowth of implanted tumors. The mechanism for increased tumor growth in the setting of liver I/R injury is unknown. To investigate the effect of I/R on tumor growth, an experimental model was used whereby small hepatic metastases form after 28 days. Mice subjected to 30 min of 70% liver ischemia at the time of tumor inoculation had significantly larger tumor number and volume, and had elevated MMP9 serum and liver tissue MMP9 as evidenced by zymography and quantitative real-time PCR. Mice treated with doxycycline, a broad-spectrum MMP inhibitor, had reduced MMP9 levels and significantly smaller tumor number and volume in the liver. MMP9-null mice were used to determine if the effects of doxycycline were due to the absence of stromal-derived MMP9. The MMP9-null mice, with or without doxycycline treatment, had reduced tumor number and volume that was equivalent to wild-type mice treated with doxycycline. These findings indicate that hepatic I/R-induced elevations in MMP9 contribute to the growth of metastatic colorectal carcinoma in the liver and that postresection MMP9 inhibition may be clinically beneficial in preventing recurrence following hepatic surgery.

Selective vitamin D receptor modulators and their effects on colorectal tumor growth

The active form of vitamin D, 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], is an endocrine hormone whose classic role is the maintenance of calcium homeostasis. It is well documented that 1,25(OH)(2)D(3) also has anti-tumor effects on a number of cancers and cancer cell lines including breast, colorectal, gastric, liver, ovarian, prostate, and non-melanoma skin cancers. Included in the anti-tumor activities of 1,25(OH)(2)D(3) are its ability to cause antiproliferation, prodifferentation and decrease angiogenesis. Furthermore, through regulation of the plaminogen activator (PA) system and a class of proteolytic enzymes called matrix metalloproteinases (MMPs), 1,25(OH)(2)D(3) reduces the invasive spread of tumor cells. Because of the calcemic limitations of using 1,25(OH)(2)D(3) as a therapy, we have tested the effects of a novel Gemini vitamin D analogue, Deuterated Gemini (DG), on mouse colorectal cancer. We demonstrated that DG is more potent in reducing tumor volume and mass, compared to control and 1,25(OH)(2)D(3). DG significantly prevented (100% reduction, p<0.05) the invasive spread of colorectal tumor cells into the surrounding muscle, and had no effect on serum calcium levels. Thus, DG acts as a selective vitamin D receptor modulator (SVDRM) by enhancing select anti-tumor characteristic 1,25(OH)(2)D(3) activities, without inducing hypercalcemia. Thus, DG shows promise in the development of colorectal cancer therapies.