Matrilysin (MMP-7) induces homotypic adhesion of human colon cancer cells and enhances their metastatic potential in nude mouse model

Nanocarriers for cancer-targeted delivery based on Pickering emulsions stabilized by casein nanoparticles

This study demonstrates the development of stimuli-responsive Pickering emulsions stabilized by casein nanoparticles (CNPs) for targeted drug delivery to colorectal cancer cells (CRC). Encapsulation of a fluorescent dye simulates therapeutic delivery, demonstrating biomedical potential. The oil-in-water nanoemulsions stabilized by CNPs function as nanocarriers sensitive to matrix metalloproteinase-7 (MMP-7), an enzyme overexpressed in CRC cells, enabling precise drug release. Emulsions exhibited strong stability due CNPs forming a robust layer at the oil-water interface, enhancing bioavailability and controlled release. Covalent modifications of CNPs with polyethyleneimine (PEI) or polyacrylic acid (PAA), and pH adjustments optimize the zeta potential, improving surface charge and delivery efficiency. Maximal CNP uptake occurred with PAA-modified CNPs (-20 mV), showing superior interaction with CRC cells compared to pristine (-6.7 mV) and PEI-modified (+30.5, +42.1 mV) CNPs. Confocal microscopy and imaging flow cytometry confirmed that CNP-stabilized emulsions enhance CRC inter-localization compared to dispersed CNPs. Nanoemulsions with the highest CNP uptake showed selective interaction with tumor cells, while minimizing oil droplet uptake, driven by nanoscale dimensions and targeted surface interactions. Enzymatic degradation of CNPs by MMP-7 induces phase separation and targeted release. This dual-functional system, leveraging charge modification and enzymatic responsiveness, highlights CNP-stabilized nanoemulsions as a promising CRC-targeted drug delivery platform.

Expression and Purification of Active Monomeric MMP7

MMP7 is the smallest member of the MMP family and plays multiple physiological and pathological roles through interaction with a variety of molecules. Purified MMP7 would be beneficial for studying its function and for the development of inhibitors, which could be potential therapeutics. Due to low levels of endogenously produced MMP7, its recombinant expression and purification using E. coli have been established. Here, we describe an effective method to express and purify an active form of MMP7. Our recent discovery is that adding high concentration of CaCl2 during refolding process prevents nonspecific binding of MMP7 to plastic and its aggregation, significantly improving the yield of active monomeric forms of MMP7.

MMP-7 expression is associated with a higher rate of tumor spread through air spaces in resected lung adenocarcinomas

OBJECTIVES

The spread through air spaces (STAS) of adenocarcinoma (ADC) is a unique pattern for local invasion, which comprises the spread of tumor cells within air spaces beyond the tumor edge without a direct connection with the primary tumor. Matrix metalloproteinase-7 (MMP-7), a secreted proteolytic enzyme that degrades various extracellular matrix components and other substrates, regulates several pathophysiological processes as well as the occurrence and development of cancers in humans. Here, we retrospectively analyzed a cohort of Japanese patients with treatment-naive, surgically-resected lung ADC to assess whether MMP-7 is associated with STAS development and if it could be used as a predictor of STAS.

MATERIALS AND METHODS

We performed histological evaluation using hematoxylin and eosin staining and immunohistochemical analysis using microarrays. Thereafter, we scored the examined tissues for immune markers to identify significant tumor STAS predictors.

RESULTS

We identified that high MMP-7 expression is an independent predictor of a high STAS incidence. Multivariate analysis revealed that MMP-7 expression was correlated with tumor behavior and poor prognosis. Furthermore, STAS remained significantly associated with a higher risk of ADC recurrence.

CONCLUSION

The development of tumor STAS could be promoted by the functioning of MMP-7. This study could be a crucial basis for future investigations on the detection of tumor STAS.

Matrix metalloproteinases and their inhibitors in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is characterized by a progressive loss of corneal endothelial cells (CECs) and an abnormal accumulation of extracellular matrix in Descemet's membrane leading to increased thickness and formation of excrescences called guttae. Extracellular matrix homeostasis is modulated by an equilibrium between matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs). This study aimed to investigate MMPs and TIMPs profile in FECD, taking into account cell morphology. Populations of FECD and healthy CECs were cultured and their conditioned media collected for analysis. The presence of proteases in the conditioned media was studied using a semi-quantitative proteome profiler array, and MMPs levels were assessed using quantitative assays (ELISA and quantitative antibody array). MMP activity was determined by zymography and fluorometry. The expression pattern of the membrane type 1-MMP (MT1-MMP, also known as MMP-14) was examined by immunofluorescence on ex vivo FECD and healthy explants of CECs attached to Descemet's membrane. Finally, MMPs and TIMPs protein expression was compared to gene expression obtained from previously collected data. FECD and healthy CEC populations generated cultures of endothelial, intermediate, and fibroblastic-like morphology. Various MMPs (MMP-1, -2, -3, -7, -8, -9, -10, and -12) and TIMPs (TIMP-1 to -4) were detected in both FECD and healthy CECs culture supernatants. Quantitative assays revealed a decrease in MMP-2 and MMP-10 among FECD samples. Both these MMPs can degrade the main extracellular matrix components forming guttae (fibronectin, laminin, collagen IV). Moreover, MMPs/TIMPs ratio was also decreased among FECD cell populations. Activity assays showed greater MMPs/Pro-MMPs proportions for MMP-2 and MMP-10 in FECD cell populations, although overall activities were similar. Moreover, the analysis according to cell morphology revealed among healthy CECs, both increased (MMP-3 and -13) and decreased (MMP-1, -9, -10, and -12) MMPs proteins along with increased MMPs activity (MMP-2, -3, -9, and -10) in the fibroblastic-like subgroup when compared to the endothelial subgroup. However, FECD CECs did not show similar behaviors between the different morphology subgroups. Immunostaining of MT1-MMP on ex vivo FECD and healthy explants revealed a redistribution of MT1-MMP around guttae in FECD explants. At the transcriptional level, no statistically significant differences were detected, but cultured FECD cells had a 12.2-fold increase in MMP1 and a 4.7-fold increase in TIMP3. These results collectively indicate different, and perhaps pathological, MMPs and TIMPs profile in FECD CECs compared to healthy CECs. This is an important finding suggesting the implication of MMPs and TIMPs in FECD pathophysiology.

Inhibitory effect of a gamma-oryzanol-rich fraction from purple rice extract on lipopolysaccharide-induced metastasis in human colon cancer cells

The incidence of colon cancer recurrence and metastasis is known to increase as an adverse effect related to postoperative infection. Lipopolysaccharide or LPS, which is derived from gram-negative bacteria, is a key inducer of inflammatory-related tumor metastasis. Although there are numerous known biological effects of purple rice extract (PRE), its protective effect on colon metastasis was unknown. This study first evaluated the effects of hexane soluble fraction (HSF) or γ-oryzanol-rich fraction of PRE on LPS-induced colon cancer adhesion and invasion, which was accomplished using adhesive and invasive assay. Gelatin zymography was also utilized for gelatinase activity and secretion. Its chelating activity was also further analyzed by reverse gelatin zymography with zinc chloride. The study findings support the synergistic effect of HSF in protection against adverse events from LPS-induced colon cancer metastasis, as shown by effects on adhesive and invasive ability as well as matrix metalloproteinase-2 secretion and activity. PRACTICAL APPLICATIONS: Bacterial infection is still one of the main adverse events following abdominal cancer surgery and is associated with an increased incidence of colon cancer metastasis. Lipopolysaccharide (LPS) is a major component of this pathogen-mediated response. This first study investigated the efficiency of a gamma-oryzanol (OR) rich fraction, collected from purple rice extract (PRE), against LPS-induced colon cancer metastasis that occurs via three main steps; adhesion to the extracellular matrix, the secretion, and activity of gelatinase and further tissue invasion. The acquired data supported the role of an OR-rich fraction from PRE as a potential inhibitor to LPS-induced colon cancer progression. This finding, related to PRE, could be further developed to create a new adjunctive treatment to reduce operative complications related to bowel cancer surgery as well as increasing the value of this crop in Thailand.

Matrix metalloproteinases cleave membrane-bound PD-L1 on CD90+ (myo-)fibroblasts in Crohn's disease and regulate Th1/Th17 cell responses

Increased T helper (Th)1/Th17 immune responses are a hallmark of Crohn's disease (CD) immunopathogenesis. CD90+ (myo-)fibroblasts (MFs) are abundant cells in the normal (N) intestinal mucosa contributing to mucosal tolerance via suppression of Th1 cell activity through cell surface membrane-bound PD-L1 (mPD-L1). CD-MFs have a decreased level of mPD-L1. Consequently, mPD-L1-mediated suppression of Th1 cells by CD-MFs is decreased, yet the mechanism responsible for the reduction in mPDL-1 is unknown. Increased expression of matrix metalloproteinases (MMPs) has been reported in CD. Herein we observed that when compared to N- and ulcerative colitis (UC)-MFs, CD-MFs increase in LPS-inducible levels of MMP-7 and -9 with a significant increase in both basal and inducible MMP-10. A similar pattern of MMP expression was observed in the CD-inflamed mucosa. Treatment of N-MFs with a combination of recombinant human MMP-7, -9 and -10 significantly decreased mPD-L1. In contrast, inhibition of MMP activity with MMP inhibitors or anti-MMP-10 neutralizing antibodies restores mPD-L1 on CD-MFs. CD-MFs demonstrated reduced capacity to suppress Th1 and Th17 responses from activated CD4+ T cells. By contrast, supplementation of the CD-MF:T-cell co-cultures with MMP inhibitors or anti-MMP neutralizing antibodies restored the CD-MF-mediated suppression. Our data suggest that (i) increased MMP-10 expression by CD-MFs and concomitant cleavage of PD-L1 from the surface of CD-MFs are likely to be one of the factors contributing to the decrease of mPD-L1-mediated suppression of Th1/Th17 cells in CD; and (ii) MMPs are likely to have a significant role in the intestinal mucosal immune responses.

Matrix metalloproteinase family gene polymorphisms and lung cancer susceptibility: an updated meta-analysis

Background

Many studies have investigated the association between matrix metalloproteinase polymorphisms and lung cancer susceptibility. However, the results are still controversial. To clarify these associations, we conducted a meta-analysis.

Methods

A systematic search of studies was conducted in PubMed, Embase, and China National Knowledge Infrastructure. Overall and subgroup analysis stratified by ethnicity was conducted. OR with 95% CI was used to assess the strength of the association. Furthermore, false-positive report probability (FPRP) tests were also performed for associations obtained in this meta-analysis.

Results

Twenty-four studies, including 10,099 cases and 9,395 controls, were analyzed. Nine polymorphisms were reported. For MMP1 -1607 1G/2G and MMP7 -181 A/G, increased lung cancer risk was found in Asians. For MMP2 -1306 C/T and MMP2 -735 C/T, decreased lung cancer risk was found in both “diverse populations” and Asians. For MMP9 -1562, C/T decreased lung cancer risk was found in both “diverse populations” and Caucasians. For MMP13 -77A/G, the A/G genotype decreased lung cancer risk in Asians. However, only associations between MMP1 -1607 1G/2G, MMP2 -1306 C/T, MMP2 -735 C/T, and MMP7 -181 A/G and lung cancer risk were considered noteworthy according to FPRP tests. There was no association between MMP3 -1171 5A/6A, MMP9 R279Q, and MMP12 -82A/G and lung cancer risk.

Conclusions

Our meta-analysis suggested that MMP1 -1607 1G/2G and MMP7 -181 A/G were risk factors for lung cancer, while MMP2 -1306 C/T, MMP2 -735 C/T, MMP9 -1562 C/T, and MMP13 -77A/G might be protective factors. However, results for MMP9 -1562 C/T and MMP13 -77A/G should be interpreted with caution due to the probability of false-positive reports.

Identification of A Gene Set Associated with Colorectal Cancer in Microarray Data Using The Entropy Method

Objective

We sought to apply Shannon’s entropy to determine colorectal cancer genes in a microarray dataset.

Materials and Methods

In the retrospective study, 36 samples were analysed, 18 colorectal carcinoma and 18 paired normal tissue samples. After identification of the gene fold-changes, we used the entropy theory to identify an effective gene set. These genes were subsequently categorised into homogenous clusters.

Results

We assessed 36 tissue samples. The entropy theory was used to select a set of 29 genes from 3128 genes that had fold-changes greater than one, which provided the most information on colorectal cancer. This study shows that all genes fall into a cluster, except for the R08183 gene.

Conclusion

This study has identified several genes associated with colon cancer using the entropy method, which were not detected by custom methods. Therefore, we suggest that the entropy theory should be used to identify genes associated with cancers in a microarray dataset.

CTHRC1 induces non-small cell lung cancer (NSCLC) invasion through upregulating MMP-7/MMP-9

Background

The strong invasive and metastatic nature of non-small cell lung cancer (NSCLC) leads to poor prognosis. Collagen triple helix repeat containing 1 (CTHRC1) is involved in cell migration, motility and invasion. The object of this study is to investigate the involvement of CTHRC1 in NSCLC invasion and metastasis.

Methods

A proteomic analysis was performed to identify the different expression proteins between NSCLC and normal tissues. Cell lines stably express CTHRC1, MMP7, MMP9 were established. Invasion and migration were determined by scratch and transwell assays respectively. Clinical correlations of CTHRC1 in a cohort of 230 NSCLC patients were analysed.

Results

CTHRC1 is overexpressed in NSCLC as measured by proteomic analysis. Additionally, CTHRC1 increases tumour cell migration and invasion in vitro. Furthermore, CTHRC1 expression is significantly correlated with matrix metalloproteinase (MMP)7 and MMP9 expression in sera and tumour tissues from NSCLC. The invasion ability mediated by CTHRC1 were mainly MMP7- and MMP9-dependent. MMP7 or MMP9 depletion significantly eradicated the pro-invasive effects mediated by CTHRC1 on NSCLC cells. Clinically, patients with high CTHRC1 expression had poor survival.

Conclusions

CTHRC1 serves as a pro-metastatic gene that contributes to NSCLC invasion and metastasis, which are mediated by upregulated MMP7 and MMP9 expression. Targeting CTHRC1 may be beneficial for inhibiting NSCLC metastasis.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4317-6) contains supplementary material, which is available to authorized users.

Metalloproteinase-1, Metalloproteinase-7, and p53 Immunoexpression and their Correlation with Clinicopathological Prognostic Factors in Colorectal Adenocarcinoma

Aim

The aim of this study was to analyze the immunoexpression of metalloproteinase-1, metalloproteinase-7, and p53 in colorectal adenocarcinoma, and to correlate this with clinicopathological prognostic factors.

Material and methods

Formalin-fixed paraffin-embedded tumor tissue from 82 patients was analyzed by means of immunohistochemistry, using the streptavidin-biotin method and the tissue microarray technique. Protein tissue expression was correlated with the variables of the degree of cell differentiation, stage, relapse-free survival, recurrence, survival, and specific mortality.

Results

All of the tumors were positive for metalloproteinase-1, while 50 (61%) were positive for metalloproteinase-7, and 32 (39%) were negative for the latter. For p53, 70 (85.4%) of the tumors were positive and 12 (14.6%) were negative. Correlation of the marker expressions separately and in conjunction did not produce any statistically significant data.

Conclusion

The immunoexpression of metalloproteinase-1, metalloproteinase-7, and p53 did not correlate with recurrence, mortality, relapse-free survival, survival, degree of cell differentiation, or staging of colorectal cancer.

Expression and clinical significance of serum MMP-7 and PTEN levels in patients with acute myeloid leukemia

The aim of this study was to examine the changes of serum matrix metalloproteinase-7 (MMP-7) and phosphatase and tension homolog (PTEN) in patients with acute myeloid leukemia (AML) at different time points following treatment. The levels of serum MMP-7 and PTEN were measured from 80 AML patients with a diagnosis of peripheral blood, immune cell phenotype, and bone marrow puncture cytology examination. Among these, there were 20 cases of complete remission, 20 cases of primary untreated patients, 21 cases of incomplete remission, and 19 cases of relapse after remission. In addition, 20 healthy adults with normal physical examination results were enrolled as the control group. Patients were divided into different groups according to the treatment period. Serum MMP-7 and PTEN levels in patients and the healthy control group were measured using an ELISA. Compared with the control group, the levels of MMP-7 of 20 primary untreated patients were significantly increased (P<0.05), while there was no significant difference for the levels of PTEN in the incomplete remission group. A comparison between the control and complete remission groups revealed that the levels of MMP-7 and PTEN in the serum samples of 21 cases of patients with incomplete remission were significantly increased (P<0.05). In addition, the content of MMP-7 in 19 patients in relapse after remission group was significantly higher (P<0.05) than that of the complete remission and healthy control groups, while the levels of serum PTEN did not show significant changes. In conclusion, the level of serum MMP-7 and PTEN in AML patients was closely related to the clinical stage and the degree of disease. The combination of MMP-7 and PTEN may provide theoretical support for the accurate diagnosis, understanding of efficacy, prognosis and improvement of survival rate of AML.

Matrix metalloproteinase-7 induces homotypic tumor cell aggregation via proteolytic cleavage of the membrane-bound Kunitz-type inhibitor HAI-1

Matrix metalloproteinase-7 (MMP-7) plays important roles in tumor progression and metastasis. Our previous studies have demonstrated that MMP-7 binds to colon cancer cells via cell surface-bound cholesterol sulfate and induces significant cell aggregation by cleaving cell-surface protein(s). These aggregated cells exhibit a dramatically enhanced metastatic potential. However, the molecular mechanism inducing this cell-cell adhesion through the proteolytic action of MMP-7 remained to be clarified. Here, we explored MMP-7 substrates on the cell surface; the proteins on the cell surface were first biotinylated, and a labeled protein fragment specifically released from the cells after MMP-7 treatment was analyzed using LC-MS/MS. We found that hepatocyte growth factor activator inhibitor type 1 (HAI-1), a membrane-bound Kunitz-type serine protease inhibitor, is an MMP-7 substrate. We also found that the cell-bound MMP-7 cleaves HAI-1 mainly between Gly⁴⁵¹ and Leu⁴⁵² and thereby releases the extracellular region as soluble HAI-1 (sHAI-1). We further demonstrated that this sHAI-1 can induce cancer cell aggregation and determined that the HAI-1 region corresponding to amino acids 141-249, which does not include the serine protease inhibitor domain, has the cell aggregation-inducing activity. Interestingly, a cell-surface cholesterol sulfate-independent proteolytic action of MMP-7 is critical for the sHAI-1-mediated induction of cell aggregation, whereas cholesterol sulfate is needed for the MMP-7-catalyzed generation of sHAI-1. Considering that MMP-7-induced cancer cell aggregation is an important mechanism in cancer metastasis, we propose that sHAI-1 is an essential component of MMP-7-induced stimulation of cancer metastasis and may therefore represent a suitable target for antimetastatic therapeutic strategies.

Peripheral membrane associations of matrix metalloproteinases

Water soluble matrix metalloproteinases (MMPs) have been regarded as diffusing freely in the extracellular matrix. Yet multiple MMPs are also observed at cell surfaces. Their membrane-proximal activities include sheddase activities, collagenolysis, bacterial killing, and intracellular trafficking reaching as far as the nucleus. The catalytic domains of MMP-7 and MMP-12 bind bilayers peripherally, each in two different orientations, by presenting positive charges and a few hydrophobic groups to the surface. Related peripheral membrane associations are predicted for other soluble MMPs. The peripheral membrane associations may support pericellular proteolysis and endocytosis. The isolated soluble domains of MT1-MMP can also associate with membranes. NMR assays suggest transient association of the hemopexin-like domains of MT1-MMP and MMP-12 with lipid bilayers. Peripheral association of soluble MMP domains with bilayers or heparin sulfate proteoglycans probably concentrates them near the membrane. This could increase the probability of forming complexes with membrane-associated proteins, such as those targeted for proteolysis. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.

Optical Interference-Free Surface-Enhanced Raman Scattering CO-Nanotags for Logical Multiplex Detection of Vascular Disease-Related Biomarkers

Matrix metalloproteinases (MMPs), specifically MMP-2, MMP-7, and MMP-9, have been discovered to be linked to many forms of vascular diseases such as stroke, and their detection is crucial to facilitate clinical diagnosis. In this work, we prepared a class of optical interference-free SERS nanotags (CO-nanotags) that can be used for the purpose of multiplex sensing of different MMPs. Multiplex detection with the absence of cross-talk was achieved by using CO-nanotags with individual tunable intrinsic Raman shifts of CO in the 1800-2200 cm^-1 region determined by the metal core and ligands of the metal carbonyl complex. Boolean logic was used as well to simultaneously probe for two proteolytic inputs. Such nanotags offer the advantages of convenient detection of target nanotags and high sensitivity as validated in the ischemia rat model.

Peptide Functionalized Gold Nanoparticles as a Stimuli Responsive Contrast Medium in Multiphoton Microscopy

There is a need for biochemical contrast mediators with high signal-to-noise ratios enabling noninvasive biomedical sensing, for example, for neural sensing and protein-protein interactions, in addition to cancer diagnostics. The translational challenge is to develop a biocompatible approach ensuring high biochemical contrast while avoiding a raise of the background signal. We here present a concept where gold nanoparticles (AuNPs) can be utilized as a stimuli responsive contrast medium by chemically triggering their ability to exhibit multiphoton-induced luminescence (MIL) when performing multiphoton laser scanning microscopy (MPM). Proof-of-principle is demonstrated using peptide-functionalized AuNPs sensitive to zinc ions (Zn²⁺). Dispersed particles are invisible in the MPM until addition of millimolar concentrations of Zn²⁺ upon which MIL is enabled through particle aggregation caused by specific peptide interactions and folding. The process can be reversed by removal of the Zn²⁺ using a chelator, thereby resuspending the AuNPs. In addition, the concept was demonstrated by exposing the particles to matrix metalloproteinase-7 (MMP-7) causing peptide digestion resulting in AuNP aggregation, significantly elevating the MIL signal from the background. The approach is based on the principle that aggregation shifts the plasmon resonance, elevating the absorption cross section in the near-infrared wavelength region enabling onset of MIL. This Letter demonstrates how biochemical sensing can be obtained in far-field MPM and should be further exploited as a future tool for noninvasive optical biosensing.

Correlations of polymorphisms in matrix metalloproteinase-1, -2, and -7 promoters to susceptibility to malignant gliomas

Background:

Oligodendrogliomas are infiltrative astrocytic tumors. They constitute about 1-5% of intracranial tumors. These have been graded into benign and malignant grades. The single nucleotide polymorphisms (SNPs) in the promoter regions of MMP genes may influence tumor development and progression. This study was done to explore the correlations of the promoter SNPs in MMP-1, MMP-2 and MMP-7 genes susceptibility in development and progression of oligodendrogliomas.

Objectives:

We aimed to investigate the association of MMP1 (−1607A > G), MMP-2 (−1306 C/T) and MMP-7(−181A > G) gene polymorphism in oligodendrogliomas (grade I, II, III).

Materials and Methods:

In the present case control study, we enrolled a total of 30 cases of oligodendrogliomas (grade I to III) confirmed by histopathology and 30 healthy cases as control. Polymorphism for MMP-1 gene (−1607A > G), MMP-2 (−1306 C/T), MMP-7(−181A > G) were genotyped by restriction fragment length polymorphism.

Results:

Frequencies of MMP-1 (−1607A > G) genotypes and 2G alleles were significantly associated with the cases of oligodendrogliomas (30%) in relation to healthy controls (13%). [OR = 6.89; P = 0.02; 95%CI= (1.33-35.62)] and [OR = 2.66; P =0.01; 95% CI= (1.26-5.64)]. A significant association of MMP-2 (−1306C/T) polymorphism with oligodendroglioma (P = 0.54) was not found, suggesting that MMP-2 (−1306C/T) polymorphism is not associated with increased oligodendroglioma susceptibility. Frequencies of MMP-7(−181A > G) genotypes and 2G alleles were significantly associated with the cases of oligodendrogliomas (33.33%) in relation to healthy controls (13.33%). [OR = 5.65; P = 0.02; 95%CI= (1.26-25.36)] and [OR = 2.49; P =0.01; 95% CI= (1.17-5.27)].

Conclusions:

MMP-1 (−1607 A > G), MMP-7(−181A > G) genotypes and 2G alleles were significantly associated with oligodendroglioma (grade I, II, III), but MMP-2 (−1306C/T) polymorphism is not associated with increased oligodendroglioma susceptibility.

Shed syndecan-2 enhances tumorigenic activities of colon cancer cells

Because earlier studies showed the cell surface heparan sulfate proteoglycan, syndecan-2, sheds from colon cancer cells in culture, the functional roles of shed syndecan-2 were assessed. A non-cleavable mutant of syndecan-2 in which the Asn¹⁴⁸-Leu¹⁴⁹ residues were replaced with Asn¹⁴⁸-Ile¹⁴⁹, had decreased shedding, less cancer-associated activities of syndecan-2 in vitro, and less syndecan-2-mediated metastasis of mouse melanoma cells in vivo, suggesting the importance of shedding on syndecan-2-mediated pro-tumorigenic functions. Indeed, shed syndecan-2 from cancer-conditioned media and recombinant shed syndecan-2 enhanced cancer-associated activities, and depletion of shed syndecan-2 abolished these effects. Similarly, shed syndecan-2 was detected from sera of patients from advanced carcinoma (625.9 ng/ml) and promoted cancer-associated activities. Furthermore, a series of syndecan-2 deletion mutants showed that the tumorigenic activity of shed syndecan-2 resided in the C-terminus of the extracellular domain and a shed syndecan-2 synthetic peptide (16 residues) was sufficient to establish subcutaneous primary growth of HT29 colon cancer cells, pulmonary metastases (B16F10 cells), and primary intrasplenic tumor growth and liver metastases (4T1 cells). Taken together, these results demonstrate that shed syndecan-2 directly enhances colon cancer progression and may be a promising therapeutic target for controlling colon cancer development.

Charge-Triggered Membrane Insertion of Matrix Metalloproteinase-7, Supporter of Innate Immunity and Tumors

Matrix metalloproteinase-7 (MMP-7) sheds signaling proteins from cell surfaces to activate bacterial killing, wound healing, and tumorigenesis. The mechanism targeting soluble MMP-7 to membranes has been investigated. Nuclear magnetic resonance structures of the zymogen, free and bound to membrane mimics without and with anionic lipid, reveal peripheral binding to bilayers through paramagnetic relaxation enhancements. Addition of cholesterol sulfate partially embeds the protease in the bilayer, restricts its diffusion, and tips the active site away from the bilayer. Its insertion of hydrophobic residues organizes the lipids, pushing the head groups and sterol sulfate outward toward the enzyme's positive charge on the periphery of the enlarged interface. Fluorescence probing demonstrates a similar mode of binding to plasma membranes and internalized vesicles of colon cancer cells. Binding of bilayered micelles induces allosteric activation and conformational change in the auto-inhibitory peptide and the adjacent scissile site, illustrating a potential intermediate in the activation of the zymogen.

Three-dimensional chemotaxis-driven aggregation of tumor cells

One of the most important steps in tumor progression involves the transformation from a differentiated epithelial phenotype to an aggressive, highly motile phenotype, where tumor cells invade neighboring tissues. Invasion can occur either by isolated mesenchymal cells or by aggregates that migrate collectively and do not lose completely the epithelial phenotype. Here, we show that, in a three-dimensional cancer cell culture, collective migration of cells eventually leads to aggregation in large clusters. We present quantitative measurements of cluster velocity, coalescence rates, and proliferation rates. These results cannot be explained in terms of random aggregation. Instead, a model of chemotaxis-driven aggregation - mediated by a diffusible attractant - is able to capture several quantitative aspects of our results. Experimental assays of chemotaxis towards culture conditioned media confirm this hypothesis. Theoretical and numerical results further suggest an important role for chemotactic-driven aggregation in spreading and survival of tumor cells.

The role of Reg IV in colorectal cancer, as a potential therapeutic target

Regenerating islet-derived family, member 4 (Reg IV), a member of the Reg gene family, has been reported to be overexpressed in gastrointestinal tract cancers. Reg IV overexpression in tumor cells has been associated with carcinogenesis, tissue regeneration, proliferation and resistance to apoptosis. Reg IV activates the epidermal growth factor receptor (EGFR) signaling pathway in colon cancer and increases expression of B-cell lymphoma-2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xl), which are associated with the inhibition of apoptosis, results in mitogenic signaling in colon cancer cells, increase cell proliferation, metastasis and decreased apoptosis. Reg IV treatment inhibits 5-fluorouracil induced apoptosis, at least two mechanisms are involved in inhibition of apoptosis by Reg IV, including Bcl-2 and dihydropyrimidine dehydrogenase (DPD). These studies may lead to novel therapeutic strategies for cancers expressing Reg IV. Recently, one proteoglycan was confirmed to disrupt this signaling pathway to perform antitumor effect. This review summaries current knowledge of the expression and roles of Reg IV in human colorectal cancer, describes the possible signaling pathway which Reg IV activates, and discusses the relevance of Reg IV as a potential therapeutic target for cancer treatment.

NOX1 to NOX2 switch deactivates AMPK and induces invasive phenotype in colon cancer cells through overexpression of MMP-7

Background

Although matrix metalloproteinase (MMP)-7 expression is correlated with increased metastatic potential in human colon cancer cells, the underlying molecular mechanism of invasive phenotype remains unknown. In the current study, we investigated the regulatory effects of membrane NADPH oxidase (NOX) and AMP activated protein kinase (AMPK) on MMP-7 expression and invasive phenotype change in colon cancer cells.

Methods

Production of superoxide anion was measured by lucigenin chemiluminescence assay using whole cells and protein extracts (NADPH oxidase activity), and intracellular reactive oxygen species (ROS) by fluorescence microscopy using 2’,7’-dichlorofluorescein diacetate (DCF-DA). Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to measure mRNA and protein levels, respectively. siRNA transfection was used to assess involvement of genes in cancer invasion, which were identified by Matrigel transwell invasion assay. Luciferase reporter assay was performed to identify transcription factors linked to gene expression.

Results

Under basal conditions, less invasive human colon cancer cells (HT29 and Caco-2) showed low MMP-7 expression but high NOX1 expression and AMPK phosphorylation. Treatment of HT29 and Caco-2 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) induced an invasive phenotype response along with corresponding increases in ROS production and NOX2 and MMP-7 expression as well as reduced AMPK phosphorylation, which resemble basal conditions of highly invasive human colon cancer cells (SW620 and HCT116). In addition, inverse regulation between AMPK phosphorylation and NOX2 and MMP-7 expression was observed in HT29 cells treated with different concentrations of exogenous hydrogen peroxide. TPA-induced invasive phenotype in HT29 cells was abolished by treatment with Vit. E, DPI, apocynin, and NOX2 siRNA but not NOX1 siRNA, indicating NOX2-derived ROS production induced an invasive phenotype. TPA-induced induction of MMP-7 expression was suppressed by AP-1, NF-κB, and MAPK (ERK, p38, and JNK) inhibitors, whereas TPA-induced expression of NOX2 and its regulators, p47phox and p67phox, was blocked by p38 and NF-κB inhibitors.

Conclusions

Molecular switch from NOX1 to NOX2 in colon cancer cells induces ROS production and subsequently enhances MMP-7 expression by deactivating AMPK, which otherwise inhibits stimulus-induced autoregulation of ROS and NOX2 gene expression.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0379-0) contains supplementary material, which is available to authorized users.

Overexpression of Reg4, alone or combined with MMP-7 overexpression, is predictive of poor prognosis in colorectal cancer

Regenerating islet-derived family, member 4 (Reg4) is a secreted protein that plays a critical role in the development of colorectal cancer (CRC). In the present study, we examined the relationship between Reg4 and matrix metalloproteinase-7 (MMP-7) expression in CRC, particularly with regard to metastasis. RT-qPCR, western blotting, tissue microarray (TMA) and immunohistochemical staining were performed to detect Reg4 and MMP-7 expression in CRC tissues and paired adjacent normal tissues. As compared with normal tissues, most paired colon cancers showed a ≥2-fold increase in the Reg4 and MMP-7 mRNA levels, which was subsequently validated by the post-transcriptional levels. Immunohistochemical analysis demonstrated that Reg4 was associated with lymph node and distant metastasis, advanced American Joint Committee on Cancer (AJCC) stage, and histologic grade. Further studies showed the correlation between Reg4 and MMP-7 expression was significant in CRC with distant metastasis (r=0.555, P=0.021) and in the lymph‑node metastasis samples (r=0.557, P<0.001). Patients with tumor positivity for the two molecules showed a worse prognosis even after radical surgery (P<0.001). Multivariate analysis revealed that patients with Reg4- and MMP-7-positive tumors had extremely poor OS (HR 4.63; 95% CI 2.43-8.81; P<0.001) and DFS (HR 3.88; 95% CI 2.08-7.22; P<0.001). Reg4 expression may be useful in the prediction of colon cancer prognosis when combined with MMP-7.

Prokineticin 1 protein expression is a useful new prognostic factor for human sporadic colorectal cancer

BACKGROUND

Hematogenous metastasis, regarded as closely related to angiogenic growth factors, is associated with colorectal cancer prognosis. The angiogenic growth factor prokineticin 1 (PROK1) has been cloned from endocrine cells. However, its protein expression in human malignant tumors has not been studied. The current study established the anti-PROK1 monoclonal antibody (mAb) and examined the relationship between the expression of PROK1 protein and human colorectal cancer.

METHODS

The expression of PROK1 protein was assessed in 620 resected sporadic colorectal cancer tissue samples by immunohistochemical staining with in-house-developed human PROK1 mAb to investigate the relationship of PROK1 expression to clinicopathologic factors, recurrence, and survival rate and to evaluate its prognostic significance.

RESULTS

The expression of PROK1 protein was detected in 36 % (223/620) of human primary colorectal cancer lesions but no in the healthy mucosa adjacent to the colorectal cancer lesions. According to the clinicopathologic examinations, the frequency of positive PROK1 expression was significantly higher in cases with serosal invasion, lymphatic invasion, venous invasion, lymph node metastasis, liver metastasis, hematogenous metastasis, and higher stage disease. The recurrence rate and prognosis for patients with PROK1 expression-positive lesions were significantly worse. In the Cox proportional hazard model, PROK1 expression was an independent prognostic factor.

CONCLUSIONS

The expression of PROK1 protein was identified for the first time as a new prognostic factor in colorectal cancer.

Pericellular proteolysis by matrix metalloproteinase-7 is differentially modulated by cholesterol sulfate, sulfatide, and cardiolipin

Matrix metalloproteinase (MMP)-7 binds to cell surface cholesterol sulfate (CS) and acts as a membrane-associated protease. We have previously found that CS modulates the substrate preference of MMP-7, thereby regulating its pericellular proteolytic action. MMP-7 potentially associates with the cell surface via sulfatide (SM4) and cardiolipin (CL) when they are overexpressed on the cell surface. Here, we investigated the molecular interaction between these acidic lipids and MMP-7 or its substrates, and their effects on the activity of MMP-7. Studies using MMP-7 variants with low CS-binding ability suggested that these lipids interact with a similar site on MMP-7. The hydroxamate-based MMP inhibitor TAPI-1 markedly reduced the affinity of MMP-7 for CS and CL, whereas that for SM4 was not affected by TAPI-1. These three acidic lipids also had different effects on the hydrolytic activity of MMP-7 towards a small peptide substrate: SM4, CL and CS reduced the activity to 80%, 92%, and 20%, respectively. Nevertheless, SM4 and CS similarly accelerated the MMP-7-catalyzed degradation of fibronectin and laminin-332, whereas CL did not. The increased proteolysis of substrate was observed only when both substrate and enzyme had affinity for the lipid, suggesting that the lipids probably bring the reactants into closer proximity. Furthermore, MMP-7 bound to cell surface SM4 or CS cleaved specific cell surface proteins and released similar fragments, whereas the cleavage was not stimulated by cell surface CL-bound MMP-7. This study provides a novel mechanism by which acidic lipids differentially regulate pericellular proteolysis by MMP-7 through allosteric alteration of the substrate-binding site and their inherent affinities for MMP-7 substrates.

Increased metabolites of 5-lipoxygenase from hypoxic ovarian cancer cells promote tumor-associated macrophage infiltration

5-lipoxygenase (5-LOX), a member of the lipoxygenase gene family, is a key enzyme assisting in the conversion of arachidonic acid to 5-HETE and leukotrienes. Tumor-associated macrophages (TAMs) have a critical role in the progression and metastasis of many tumors, including ovarian tumors. Moreover, TAMs are often found in a high density in the hypoxic areas of tumors. However, the relevant mechanisms have not been studied explicitly until now. In this study, we found that the expression of 5-LOX strongly correlated with the density of TAMs in hypoxic areas of human ovarian tumor tissues. In cultured ovarian cancer cells, 5-LOX metabolites were increased under hypoxic conditons. Increased 5-LOX metabolites from hypoxic ovarian cancer cells promoted migration and invasion of macrophages, which was further demonstrated to be mediated by the upregulation of matrix metalloproteinase (MMP)-7 expression through the p38 pathway. Besides, we also showed that 5-LOX metabolites enhanced the release of tumor necrosis factor (TNF-α) and heparin-binding epidermal growth factor-like growth factor through upregulation of MMP-7. Furthermore, in animal models, Zileuton (a selective and specific 5-LOX inhibitor) reduced the MMP-7 expression and the number of macrophages infiltrating in the xenograft. Our findings suggest for the first time that increased metabolites of 5-LOX from hypoxic ovarian cancer cells promote TAM infiltration. These results of this study have immediate translational implications for the therapeutic exploitation of TAMs.

Multiplexed cytokine profiling of serum for detection of colorectal cancer

AIM

To evaluate the concentrations of eight cytokines in order to identify potential biomarkers for assisting in the detection of colorectal cancer.

MATERIALS & METHODS

The concentrations of IFN-γ, IL-10, IL-6, IL-8, TNF-α, MMP-2, MMP-7 and MMP-9 were detected in the sera of 69 healthy controls, 93 colorectal adenoma patients and 149 colorectal cancer (CRC) patients.

RESULTS

Multivariate logistic regression analyses, which included CEA, CA199, IL-8, TNF-α and MMP-7, were used to evaluate the diagnostic value for differentiating between colorectal adenoma and CRC. The area under the curve was 0.945 (95% CI: 0.909-0.981). The sensitivity and specificity were 85.86 and 96.78%, respectively. Compared with the conventional biomarkers CEA and CA199, multivariate logistic regression showed significant improvement.

CONCLUSION

Our data demonstrated that testing using a panel of three serum cytokines, CEA and CA199 may have strong potential to assist in the detection of CRC.

Molecular forms of the insulin-like growth factor-binding protein-2 in patients with colorectal cancer

The components of the insulin-like growth factor (IGF) system and molecules with which they interact are associated with the neoplastic transformation of cells in colorectal cancer. The IGF-binding protein-2 (IGFBP-2) plays a significant role in mitotic stimulation of the cancer cells and its concentration is significantly elevated in tumor states. Little is known about IGFBP-2 at the molecular level and the purpose of this study was to examine the interactions between IGFBP-2 and some other proteins, the fragmentation pattern and posttranslational modifications that might have occurred due to a disease. Results have shown that the amount of monomer IGFBP-2 was 20-30% greater in patients with cancer and the amount of fragmented IGFBP-2 was doubled compared to healthy people, whereas the portion of IGFBP-2 in complex with α2 macroglobulin (α2M) was 2.5 times lower in cancer patients. According to this distribution, IGFBP-2 was not only increasingly synthetized in patients with cancer, but also the amount involved in complexes with α2M was reduced favoring the existence of binary IGFBP-2/IGF complexes, free to leave the circulation. Both IGFBP-2 and α2M were significantly more oxidized in patients with colon cancer than in healthy individuals and α2M was additionally sialylated. It can be speculated that the formation of IGFBP-2/α2M complexes is part of the control mechanism involved in the regulation of IGFBP-2 and, consequently, IGF availability. It also seems that posttranslational modifications are more important factors in determining the amount of IGFBP-2/α2M complexes than the actual quantity of these two proteins.

Peptide functionalized gold nanoparticles for colorimetric detection of matrilysin (MMP-7) activity

A peptide with two cleavage sites for MMP-7 has been synthesized and immobilized on gold nanoparticles (AuNPs) through a cysteine residue. Digestion of the peptide by MMP-7 decreases its size and net charge, which leads to the aggregation of the AuNPs. The color shift caused by aggregation enables a direct and quantitative measurement of the concentration and activity of MMP-7 with an estimated limit of detection of ∼5 nM (0.1 μg mL(-1)).

β,β-carotene 15,15'-monooxygenase and its substrate β-carotene modulate migration and invasion in colorectal carcinoma cells

BACKGROUND

β,β-Carotene 15,15'-monooxygenase (BCMO1) converts β-carotene to retinaldehyde. Increased β-carotene consumption is linked to antitumor effects. Retinoic acid reduces the invasiveness in cancer, through inhibition of matrix metalloproteinases (MMPs). In our studies of a mouse model that develops intestinal tumors after low dietary folate, we found reduced BCMO1 expression in normal preneoplastic intestine of folate-deficient tumor-prone mice.

OBJECTIVE

Our goal was to determine whether BCMO1 expression could influence transformation potential in human colorectal carcinoma cells, by examining the effect of BCMO1 modulation on cellular migration and invasion, and on expression of MMPs.

DESIGN

LoVo colon carcinoma cells were transfected with BCMO1 small interfering RNA (siRNA) or scrambled siRNA. Migration and invasion were measured, and the expression of BCMO1, MMP7, and MMP28 was assessed by quantitative reverse-transcriptase polymerase chain reaction. These variables were also measured after treatment of cells with retinoic acid, 5-aza-2'-deoxycytidine, folate-depleted/high-methionine medium, and β-carotene.

RESULTS

Retinoic acid decreased the migration, invasion, and expression of MMP28 mRNA. Transfection of cells with BCMO1 siRNA inhibited BCMO1 expression, enhanced migration and invasion, and increased expression of MMP7 and MMP28. 5-Aza-2'-deoxycytidine decreased, whereas folate-depleted/high-methionine medium increased invasiveness. β-Carotene increased BCMO1 expression and reduced invasiveness with a decrease in expression of MMP7 and MMP28.

CONCLUSIONS

Inhibition of BCMO1 expression is associated with increased invasiveness of colon cancer cells and increased expression of MMP7 and MMP28. β-Carotene can upregulate BCMO1 and reverse these effects. These novel associations suggest a critical role for BCMO1 in cancer and provide a mechanism for the proposed antitumor effects of β-carotene.

Small interfering RNA-mediated downregulation of beta-catenin inhibits invasion and migration of colon cancer cells in vitro

Background

Abnormal regulation of Wnt/β-catenin signaling and subsequently increased β-catenin expression have been found to be involved in the proliferation and growth of colon cancer cells. Whether the down-regulation of β-catenin in colon cancer may result in compromised invasion and migration in vitro still remains to be determined.

Material/Methods

A human colon cancer cell line (LoVo cells) was transfected with small interfering RNA (siRNA) targeting β-catenin. RT-PCR, Western blot assay, flow cytometry, cell adhesion assay, scratch wound assay, and matrigel invasion assay were performed, and the correlation between cell invasion and migration and β-catenin expressions was analyzed.

Results

siRNA-mediated down-regulation of β-catenin elevated the E-cadherin expression but reduced the MMP-7 and CD44v6 expressions, which increased the adhesion between LoVo cells but decreased the adhesion of LoVo cells to fibronectin. Significant inhibition of cell invasion and migration was also observed following RNA interference with β-catenin siRNA.

Conclusions

siRNA-mediated downregulation of β-catenin could be valuable for defining gene expression and functional programs downstream of oncogenic β-catenin signals, which, in turn, may be helpful to isolate novel diagnostic markers, and for designing tumor-specific intervention at downstream targets of oncogenic β-catenin.

Significance of regenerating islet-derived type IV gene expression in gastroenterological cancers

The regenerating islet-derived members (Reg), a group of small secretory proteins, which are involved in cell proliferation or differentiation in digestive organs, are upregulated in several gastrointestinal cancers, functioning as trophic or antiapoptotic factors. Regenerating islet-derived type IV (RegIV), a member of the Reg gene family, has been reported to be overexpressed in gastroenterological cancers. RegIV overexpression in tumor cells has been associated with carcinogenesis, cell growth, survival and resistance to apoptosis. Cancer tissue expressing RegIV is generally associated with more malignant characteristics than that without such expression, and RegIV is considered a novel prognostic factor as well as diagnostic marker in some gastroenterological cancers. We previously investigated the expression levels of RegIV mRNA of 202 surgical colorectal cancer specimens with quantitative real-time reverse-transcriptase polymerase chain reaction and reported that a higher level of RegIV gene expression was a significant independent predictor of colorectal cancer. The biologic functions of RegIV protein in cancer tissue, associated with carcinogenesis, anti-apoptosis and invasiveness, are being elucidated by molecular investigations using transfection techniques or neutralizing antibodies of RegIV, and the feasibility of antibody therapy targeting RegIV is being assessed. These studies may lead to novel therapeutic strategies for gastroenterological cancers expressing RegIV. This review article summarizes the current information related to biological functions as well as clinical importance of RegIV gene to clarify the significance of RegIV expression in gastroenterological cancers.

Recent advances in targeted endoscopic imaging: Early detection of gastrointestinal neoplasms

Molecular imaging has emerged as a new discipline in gastrointestinal endoscopy. This technology encompasses modalities that can visualize disease-specific morphological or functional tissue changes based on the molecular signature of individual cells. Molecular imaging has several advantages including minimal damage to tissues, repetitive visualization, and utility for conducting quantitative analyses. Advancements in basic science coupled with endoscopy have made early detection of gastrointestinal cancer possible. Molecular imaging during gastrointestinal endoscopy requires the development of safe biomarkers and exogenous probes to detect molecular changes in cells with high specificity anda high signal-to-background ratio. Additionally, a high-resolution endoscope with an accurate wide-field viewing capability must be developed. Targeted endoscopic imaging is expected to improve early diagnosis and individual therapy of gastrointestinal cancer.

The role of immunoglobulin superfamily cell adhesion molecules in cancer metastasis

Metastasis is a major clinical problem and results in a poor prognosis for most cancers. The metastatic pathway describes the process by which cancer cells give rise to a metastatic lesion in a new tissue or organ. It consists of interconnecting steps all of which must be successfully completed to result in a metastasis. Cell-cell adhesion is a key aspect of many of these steps. Adhesion molecules belonging to the immunoglobulin superfamily (Ig-SF) commonly play a central role in cell-cell adhesion, and a number of these molecules have been associated with cancer progression and a metastatic phenotype. Surprisingly, the contribution of Ig-SF members to metastasis has not received the attention afforded other cell adhesion molecules (CAMs) such as the integrins. Here we examine the steps in the metastatic pathway focusing on how the Ig-SF members, melanoma cell adhesion molecule (MCAM), L1CAM, neural CAM (NCAM), leukocyte CAM (ALCAM), intercellular CAM-1 (ICAM-1) and platelet endothelial CAM-1 (PECAM-1) could play a role. Although much remains to be understood, this review aims to raise the profile of Ig-SF members in metastasis formation and prompt further research that could lead to useful clinical outcomes.

Expression of matrix metalloproteinase-7 is an unfavorable prognostic factor in intrahepatic cholangiocarcinoma

BACKGROUND

Intrahepatic cholangiocarcinoma (IHCC) is a highly malignant neoplasm, but the prognostic factors of IHCC are not yet fully understood. The matrix metalloproteinases (MMPs) are known to be related to tumor viability. The aim of this study was to evaluate the prognostic significance of clinicopathological and immunohistochemical characteristics of resected IHCC.

PATIENTS AND METHODS

From 1996 to 2006, we surgically treated 35 patients with IHCC. Clinicopathological and immunohistochemical characteristics, including expression of MMPs, vascular endothelial growth factor, and epidermal growth factor receptor in the resected specimens, were investigated, and overall survival rates were evaluated with regard to the characteristics using univariate and multivariate analyses.

RESULTS

Univariate analysis revealed the significant prognostic factors to be preoperative serum CEA and CA19-9, intraoperative transfusion, tumor size, surgical margin, lymph node metastasis, invasion of portal and hepatic vein, intrahepatic metastasis, UICC stage, and expression of MMP-7. Subsequent multivariate analysis indicated that MMP-7 was an independent prognostic factor (hazard ratio (HR), 4.698; 95% confidence interval (CI), 0.057-0.866; P = 0.03) along with intrahepatic metastasis (HR, 5.694; 95% CI, 0.029-0.706; P = 0.017).

CONCLUSION

MMP-7 expression is associated with a poor prognosis in patients with resected IHCC.

Regulation of matrix metalloproteinases activity studied in human endometrium as a paradigm of cyclic tissue breakdown and regeneration

When abundant and activated, matrix metalloproteinases (MMPs, or matrixins) degrade most, if not all, constituents of the extracellular matrix (ECM). The resulting massive tissue breakdown is best exemplified in humans by the menstrual lysis and shedding of the endometrium, the mucosa lining the uterus. After menstruation, MMP activity needs to be tightly controlled as the endometrium regenerates and differentiates to avoid abnormal tissue breakdown while allowing tissue repair and fine remodelling to accommodate implantation of a blastocyst. This paper reviews how MMPs are massively present and activated in the endometrium at menstruation, and how their activity is tightly controlled at other phases of the cycle. Progesterone represses expression of many but not all MMPs. Its withdrawal triggers focal expression of MMPs specifically in the areas undergoing lysis, an effect mediated by local cytokines such as interleukin-1α, LEFTY-2, tumour necrosis factor-α and others. MMP-3 is selectively expressed at that time and activates proMMP-9, otherwise present in latent form throughout the cycle. In addition, a large number of neutrophils loaded with MMPs are recruited at menstruation through induction of chemokines, such as interleukin-8. At the secretory phase, progesterone repression of MMPs is mediated by transforming growth factor-β. Tissue inhibitors of metalloproteinases (TIMPs) are abundant at all phases of the cycle to prevent any undue MMP activity, but are likely overwhelmed at menstruation. At other phases of the cycle, MMPs can elude TIMP inhibition as exemplified by recruitment of active MMP-7 to the plasma membrane of epithelial cells, allowing processing of membrane-associated growth factors needed for epithelial repair and proliferation. Finally, receptor-mediated endocytosis through low density lipoprotein receptor-related protein-1 (LRP-1) efficiently clears MMP-2 and -9 at the proliferative and secretory phases. This mechanism is probably essential to prevent any excessive ECM degradation by the active form of MMP-2 that is permanently present. However, shedding of the ectodomain of LRP-1 specifically at menstruation prevents endocytosis of MMPs allowing full degradation of the ECM. Thus endometrial MMPs are regulated at the levels of transcription, release from infiltrating neutrophils, activation, binding to the cell membrane, inhibition by TIMPs and endocytic clearance by LRP-1. This allows tight control during endometrial growth and differentiation but results in a burst of activity for menstrual tissue breakdown. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.

Stable differences in intrinsic mitochondrial membrane potential of tumor cell subpopulations reflect phenotypic heterogeneity

Heterogeneity among cells that constitute a solid tumor is important in determining disease progression. Our previous work established that, within a population of metastatic colonic tumor cells, there are minor subpopulations of cells with stable differences in their intrinsic mitochondrial membrane potential (ΔΨm), and that these differences in ΔΨm are linked to tumorigenic phenotype. Here we expanded this work to investigate primary mammary, as well as colonic, tumor cell lines. We show that within a primary mammary tumor cell population, and in both primary and metastatic colonic tumor cell populations, there are subpopulations of cells with significant stable variations in intrinsic ΔΨm. In each of these 3 tumor cell populations, cells with relatively higher intrinsic ΔΨm exhibit phenotypic properties consistent with promotion of tumor cell survival and expansion. However, additional properties associated with invasive potential appear in cells with higher intrinsic ΔΨm only from the metastatic colonic tumor cell line. Thus, it is likely that differences in the intrinsic ΔΨm among cells that constitute primary mammary tumor populations, as well as primary and metastatic colonic tumor populations, are markers of an acquired tumor phenotype which, within the context of the tumor, influence the probability that particular cells will contribute to disease progression.

Relationship between RegIV gene expression to outcomes in colorectal cancer

BACKGROUND

Regenerating islet-derived family members (Reg) are superfamily of calcium-dependant lectins that are expressed in the proximal gastrointestinal tract and ectopically at other sites in the setting of tissue injury. The regenerating islet-derived family member 4 (RegIV) gene has been reported in various cancers, associating with diverse functions. This study examined the relation of the relative expression of RegIV gene to clinicopathological factors and outcomes in patients with colorectal cancer (CRC).

METHODS

We studied surgical specimens of cancer tissue and adjacent normal mucosa obtained from 202 patients with untreated CRC. The relative expression levels of RegIV mRNA in cancer and in normal adjacent mucosa were measured by quantitative real-time reverse-transcriptase polymerase chain reaction.

RESULTS

RegIV gene expression was higher in cancer tissue than in adjacent normal mucosa. The multivariate analysis of clinicopathological factors for 5-year overall survival showed a higher level of RegIV gene expression was a significant independent predictor. Overall survival at 5 years differed significantly between patients with high RegIV gene expression and those with low expression.

CONCLUSIONS

Overexpression of the RegIV gene is considered a useful independent predictor of outcomes in patients with CRC.

Distinct profiles of epigenetic evolution between colorectal cancers with and without metastasis

Liver metastasis is a fatal step in the progression of colorectal cancer (CRC); however, the epigenetic evolution of this process is largely unknown. To decipher the epigenetic alterations during the development of liver metastasis, the DNA methylation status of 12 genes, including 5 classical CpG island methylator phenotype (CIMP) markers, was analyzed in 62 liver metastases and in 78 primary CRCs (53 stage I-III; 25 stage IV). Genome-wide methylation analysis was also performed in stage I-III CRCs and in paired primary and liver metastatic cancers. Methylation frequencies of MGMT and TIMP3 increased progressively from stage I-III CRCs to liver metastasis (P = 0.043 and P = 0.028, respectively). The CIMP-positive cases showed significantly earlier recurrence of disease than did CIMP-negative cases with liver metastasis (P = 0.030), whereas no such difference was found in stage I-III CRCs. Genome-wide analysis revealed that more genes were methylated in stage I-III CRCs than in paired stage IV samples (P = 0.008). Hierarchical cluster analysis showed that stage I-III CRCs and stage IV CRCs were clustered into two distinct subgroups, whereas most paired primary and metastatic cancers showed similar methylation profiles. This analysis revealed distinct methylation profiles between stage I-III CRCs and stage IV CRCs, which may reflect differences in epigenetic evolution during progression of the disease. In addition, most methylation status in stage IV CRCs seems to be established before metastasis.

Serum matrilysin correlates with poor survival independently of KRAS and BRAF status in refractory advanced colorectal cancer patients treated with irinotecan plus cetuximab

The purpose of the study was to prospectively explore the role of serum MMP-7 as a predictive and prognostic marker of anti-epidermal growth factor receptor (EGFR) therapy and irinotecan efficacy in third-line advanced colorectal cancer therapy. One hundred patients were recruited prospectively from six Spanish hospitals. Patients were treated with biweekly irinotecan 180 mg/m(2) and cetuximab 400 mg/m(2) (loading dose) and weekly cetuximab 250 mg/m(2) until progressive disease or unacceptable toxicity. Baseline MMP-7 was determined using a quantitative solid-phase sandwich ELISA. KRAS and BRAF mutational status were also assessed. The clinical endpoints examined were overall survival (OS), progression-free survival (PFS), and response rate. No association between serum MMP-7 and neither KRAS nor BRAF mutational status was found. The multivariate analysis revealed that MMP-7 predicts PFS both in wild-type (WT) KRAS patients (HR 1.03, 95% CI 1.00-1.06; p = 0.046) and in mutant KRAS patients (HR 1.18, 95% CI 1.01-1.35; p = 0.036). The presence of mutant BRAF was associated with shorter PFS (HR 8.49, 95% CI 2.88-25.0; p < 0.001) and worse OS (HR 3.55, 95% CI 1.39-9.09; p = 0.008) in the subset of WT KRAS patients. Serum MMP-7 is associated with PFS in colorectal patients treated with anti-EGFR therapy as third-line treatment independently of KRAS status.

Cholesterol sulfate alters substrate preference of matrix metalloproteinase-7 and promotes degradations of pericellular laminin-332 and fibronectin

Localization of secreted matrix metalloproteinases (MMPs) on the cell surface is required not only for processing of cell surface proteins, but also for controlled degradation of the extracellular matrix (ECM). Our previous study demonstrated that binding of MMP-7 (matrilysin) to cell surface cholesterol sulfate (CS) is essential for the cell membrane-associated proteolytic action of this MMP. In this study, we investigated the role of CS in the MMP-7-catalyzed degradation of protein components of ECM. We found that the degradation of laminin-332 (laminin-5) catalyzed by MMP-7 was accelerated dramatically in the presence of CS, whereas the sulfated lipid inhibited the degradation of casein catalyzed by the protease. The MMP-7-catalyzed degradation of fibronectin was partially inhibited in the presence of low concentrations of CS, whereas it was accelerated significantly at high concentrations of the lipid. Therefore, it is likely that CS alters the substrate preference of MMP-7. We also found that the proteins of which MMP-7-catalyzed degradation were accelerated by CS also had affinities for CS, suggesting that CS facilitates the proteolyses by cross-linking MMP-7 to its substrates. Moreover, MMP-7 tethered to cancer cell surface via CS degraded fibronectin and laminin-332 coated on a culture plate. The degradations of the adhesive proteins led to significant detachment of the cells from the plate. Taken together, our findings provide a novel mechanism in which cell surface CS promotes the proteolytic activities of MMP-7 toward selective substrates in the pericellular ECM, thereby contributing to cancer cell migration and metastasis.

MMP-7 as a prognostic marker in colorectal cancer

Matrix metalloproteinase-7 is capable of degrading many extracellular matrix proteins and cellular adhesions. In many malignancies, it is overexpressed, and it plays a role in cancer progression by enhancing tumor invasion and thereby metastatic potential. The purpose of this study was to evaluate the association between MMP-7 tissue expression and prognosis in colorectal cancer. From 623 patients who underwent surgery for colorectal cancer, surgical specimens were collected into tissue array blocks and stained by immunohistochemistry for MMP-7. Specimens from 545 patients were suitable for analysis. In specimens from 105 patients (19.3%), MMP-7 scored as high; in 103 (18.9%), as moderate; and in 134 (24.9%), as mild. In 203 cases (37.2%), immunoreactivity was negative. A significant correlation appeared between MMP-7 immunoexpression and tumor differentiation. High MMP-7 positivity associated with poor prognosis during a 5-year follow-up. During longer follow-up, the differences in survival between groups disappeared. MMP-7 is a potential target for tumor therapy, which should be evaluated in clinical trials.

Matrix metalloproteinase-7 as a marker of metastasis and predictor of poor survival in bladder cancer

Matrix metalloproteinases (MMPs) play an important role in tumor progression and metastasis. Here, we investigated the prognostic relevance of MMP-7 in urinary bladder cancer. MMP-7 gene expression was measured in tissue samples of 101 patients using quantitative real-time PCR. Circulating MMP-7 serum levels of 98 individuals (79 patients and 19 controls) were analyzed by enzyme-linked immunosorbent assay. The results were compared with the clinical follow-up data, performing Kaplan-Meier log-rank test as well as univariate and multivariate Cox analysis. In representative cases, immunohistochemical analysis for MMP-7 was performed. We detected significantly elevated MMP-7 levels both in tissue and serum samples of patients with metastatic disease (P = 0.001 and P = 0.002). Multivariate analysis revealed that high MMP-7 tissue expression and serum concentration are stage- and grade-independent predictors of both metastasis-free (hazard ratio [HR] = 3.80, 95% confidence interval [CI], 1.29-11.23, P = 0.016, and HR = 2.53, 95% CI, 1.01-6.37, P = 0.048) and disease-specific survival (HR = 1.89, 95% CI, 1.00-3.55, P = 0.050 and HR = 1.95, 95% CI, 1.03-3.71, P = 0.041). Based on these findings, we conclude that MMP-7 is a promising marker to detect present and to predict future metastasis. Serum MMP-7 analysis provides information about the risk of metastasis before surgery which could help to optimize therapeutic procedures. Furthermore, high MMP-7 tissue and/or serum levels could identify patients most likely to benefit from early adjuvant chemotherapy.

Vimentin and desmin possess GlcNAc-binding lectin-like properties on cell surfaces

Vimentin and desmin are intermediate filament proteins found in various mesenchymal and skeletal muscle cells, respectively. These proteins play an important role in the stabilization of the cytoplasmic architecture. Here, we found, using artificial biomimicking glycopolymers, that vimentin and desmin possess N-acetylglucosamine (GlcNAc)-binding lectin-like properties on the cell surfaces of various vimentin- and desmin-expressing cells such as cardiomyocytes and vascular smooth muscle cells. The rod II domain of these proteins was demonstrated to be localized to the cell surface and to directly bind to the artificial biomimicking GlcNAc-bearing polymer, by confocal laser microscopy and surface plasmon resonance analysis. These glycopolymers strongly interact with lectins and are useful tools for the analysis of lectin-carbohydrate interactions, since glycopolymers binding to lectins can induce the clustering of lectins due to multivalent glycoside ligand binding. Moreover, immunocytochemistry and pull-down assay with His-tagged vimentin-rod II domain protein showed that the vimentin-rod II domain interacts with O-GlcNAc proteins. These results suggest that O-GlcNAc proteins might be one candidate for physiological GlcNAc-bearing ligands with which vimentin and desmin interact. These findings demonstrate a novel function of vimentin and desmin that does not involve stabilization of the cytoplasmic architecture by which these proteins interact with physiological GlcNAc-bearing ligands such as O-GlcNAc proteins on the cell surface through their GlcNAc-binding lectin-like properties.

PDEF is a negative regulator of colon cancer cell growth and migration

ETS is a family of transcriptional regulators with functions in most biological processes. Dysregulated ETS factor function leads to altered expression of multiple genes that play critical roles in many of the processes required for cancer progression. While the Ets family gene, prostate-derived ETS factor (PDEF), is expressed in epithelial tissues including prostate, breast, and colon, PDEF protein expression has been found to be reduced or lost during prostate and breast cancer progression. The goal of this study was to examine the expression and biologic impact of altered PDEF expression in colon cancer. PDEF mRNA and protein are not detectable in several colon-cancer-derived cell lines. Re-expression of PDEF in colon cancer cells inhibits growth and migration. Growth affects are due to altered cellular proliferation, indicated by increased altered cell population in G(1) and S phases of the cell cycle, as well as increased apoptosis. Relevant to its modulation of growth and migration phenotypes, PDEF expression resulted in altered expression of genes with established roles in cell cycle, motility, and invasion. Furthermore, chromatin immunoprecipitation studies show that p21 and urokinase plasminogen activator (uPA) are direct PDEF transcriptional targets. While non-tumor colon epithelium expresses PDEF mRNA and protein, the majority of tumors showed decreased mRNA and/or protein expression. In human tumor tissue samples, PDEF expression was inversely correlated with the expression levels of uPA. Collectively, the data support the model that PDEF is a negative regulator of tumor progression by modulating the expression of growth and migration promoting genes.

Matrilysin (MMP-7) cleaves C-type lectin domain family 3 member A (CLEC3A) on tumor cell surface and modulates its cell adhesion activity

Matrilysin (MMP-7) plays important roles in tumor progression. Previous studies have suggested that MMP-7 binds to tumor cell surface and promotes their metastatic potential. In this study, we identified C-type lectin domain family 3 member A (CLEC3A) as a membrane-bound substrate of MMP-7. Although this protein is known to be expressed specifically in cartilage, its message was found in normal breast and breast cancer tissues as well as breast and colon cancer cell lines. Because few studies have been done on CLEC3A, we overexpressed its recombinant protein in human cancer cells. CLEC3A was found in the cell membrane, extracellular matrix (ECM), and culture medium of the CLEC3A-expressing cells. CLEC3A has a basic sequence in the NH(2)-terminal domain and showed a strong heparin-binding activity. MMP-7 cleaved the 20-kDa CLEC3A protein, dividing it to a 15-kDa COOH-terminal fragment and an NH(2)-terminal fragment with the basic sequence. The 15-kDa fragment no longer had heparin-binding activity. Treatment of the CLEC3A-expressing cells with MMP-7 released the 15-kDa CLEC3A into the culture supernatant. Furthermore, the 20-kDa CLEC3A promoted cell adhesion to laminin-332 and fibronectin substrates, but this activity was abrogated by the cleavage by MMP-7. These results suggest that CLEC3A binds to heparan sulfate proteoglycans on cell surface, leading to the enhancement of cell adhesion to integrin ligands on ECM. It can be speculated that the cleavage of CLEC3A by MMP-7 weakens the stable adhesion of tumor cells to the matrix and promotes their migration in tumor microenvironments.