Suppression of matrilysin inhibits colon cancer cell invasion in vitro

Natural and synthetic retinoids in preclinical colorectal cancer models

Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality worldwide. Although targeted therapy in combination with chemotherapy in CRC prolongs the overall survival of patients with metastatic disease, acquired resistance and relapse hinder their clinical benefits. Moreover, patients with some specific genetic profile are unlikely to benefit from targeted therapy, suggesting the need for safe and effective treatment strategies. Retinoids, comprising of natural and synthetic analogs, are a class of chemical compounds that regulate cellular proliferation, differentiation, and cell death. Retinoids have been used in the clinic for several leukemias and solid tumors, either as single agents or in combination therapy. Furthermore, retinoids have shown potent chemotherapeutic and chemopreventive properties in different cancer models, including CRC. In this review, we summarize the major preclinical findings in CRC in which natural and synthetic retinoids showed promising antitumor activities and stress on the proposed mechanisms of action. Understanding of the retinoids' antitumor mechanisms would provide insights to support and warrant their development in the management of CRC.

Stiff substrates increase YAP-signaling-mediated matrix metalloproteinase-7 expression

Abnormally stiff substrates have been shown to trigger cancer progression. However, the detailed molecular mechanisms underlying this trigger are not clear. In this study, we cultured T84 human colorectal cancer cells on plastic dishes to create a stiff substrate or on collagen-I gel to create a soft substrate. The stiff substrate enhanced the expression of matrix metalloproteinase-7 (MMP-7), an indicator of poor prognosis. In addition, we used polyacrylamide gels (2, 67 and 126 kPa) so that the MMP-7 expression on the 126-kPa gel was higher compared with that on the 2-kPa gel. Next, we investigated whether yes-associated protein (YAP) affected the MMP-7 expression. YAP knockdown decreased MMP-7 expression. Treatment with inhibitors of epidermal growth factor receptor (EGFR) and myosin regulatory light chain (MRLC) and integrin-α2 or integrin-β1 knockdown downregulated MMP-7 expression. Finally, we demonstrated that YAP, EGFR, integrin-α2β1 and MRLC produced a positive feedback loop that enhanced MMP-7 expression. These findings suggest that stiff substrates enhanced colorectal cancer cell viability by upregulating MMP-7 expression through a positive feedback loop.

microRNA-139-5p exerts tumor suppressor function by targeting NOTCH1 in colorectal cancer

BACKGROUND

miR-139-5p was identified to be significantly down-regulated in colon tumor tissues by miRNA array. We aimed to clarify its biological function, molecular mechanisms and direct target gene in colorectal cancer (CRC).

METHODS

The biological function of miR-139-5p was examined by cell growth, cell cycle and apoptosis analysis in vitro and in vivo. miR-139-5p target gene and signaling pathway was identified by luciferase activity assay and western blot.

RESULTS

miR-139-5p was significantly down-regulated in primary tumor tissues (P < 0.0001). Ectopic expression of miR-139-5p in colon cancer cell lines significantly suppressed cell growth as evidenced by cell viability assay (P < 0.001) and colony formation assay (P < 0.01) and in xenograft tumor growth in nude mice (P < 0.01). miR-139-5p induced apoptosis (P < 0.01), concomitantly with up-regulation of key apoptosis genes including cleaved caspase-8, caspase-3, caspase-7 and PARP. miR-139-5p also caused cell cycle arrest in G0/G1 phase (P < 0.01), with upregulation of key G0/G1 phase regulators p21Cip1/Waf1 and p27Kip1. Moreover, miR-139-5p inhibited cellular migration (P < 0.001) and invasiveness (P < 0.001) through the inhibition of matrix metalloproteinases (MMP)7 and MMP9. Oncogene NOTCH1 was revealed to be a putative target of miR-139-5p, which was inversely correlated with miR-139-5p expression (r = -0.3862, P = 0.0002).

CONCLUSIONS

miR-139-5p plays a pivotal role in colon cancer through inhibiting cell proliferation, metastasis, and promoting apoptosis and cell cycle arrest by targeting oncogenic NOTCH1.

Extracellular calcium-sensing receptor/PTH knockout mice colons have increased Wnt/β-catenin signaling, reduced non-canonical Wnt signaling, and increased susceptibility to azoxymethane-induced aberrant crypt foci

Epidemiological evidence suggests increased dietary calcium and dairy products reduce the onset of colon cancer. To understand a role of the colonic extracellular calcium-sensing receptor (CaSR) in calcium-mediated chemoprevention of colon cancer, we induced formation of aberrant crypt foci (ACF) caused by azoxymethane (AOM) injection in 'rescued' CaSR-/PTH- (C-/P-) double knockout colons compared with colons from control CaSR+/PTH+ (C+/P+) mice. C-/P- colonic epithelia had increased Wnt/β-catenin signaling as evidenced by 3-8-fold increases in Wnt3a, CyclinD1, and MMP-7 proteins compared with C+/P+ colonic epithelia. The C-/P- colonic epithelia had reduced Wnt5a and Ror2, and a three-fold increase in TNFR1 compared with C+/P+ epithelia. The C-/P- colons and small intestine had extensive neutrophil infiltration with myeloperoxidase (MPO) levels 18-fold higher then C+/P+ small intestine and colon. Saline-injected C-/P- colons had the same number of ACF/cm(2) as C+/P+ colons, which were injected with AOM. However, there were eight times more ACF/cm(2) in the C-/P- injected with AOM compared with C+/P+ colons, which received AOM. Together our results suggest both inflammation and Wnt/β-catenin signaling are increased in the epithelia of 'rescued' CaSR/PTH double knockout colons, and the capacity for non-canonical Wnt signaling through Wnt5a/Ror2 engagement is reduced. The loss of the colonic CaSR increased the number of ACF/cm(2) in response to AOM injection, suggesting colonic CaSR may mediate the chemoprotective effect of increased dietary calcium against colorectal cancer observed in humans.

The forkhead box transcription factor FOXC1 promotes breast cancer invasion by inducing matrix metalloprotease 7 (MMP7) expression

Therapeutic options for treatment of basal-like breast cancers are limited and identification of molecular targets for novel therapies to treat this aggressive cancer is urgently needed. Recently, FOXC1, a forkhead box transcription factor, was identified as a functionally important biomarker of breast cancer aggressiveness and the basal-like breast cancer subtype. However, the mechanism through which FOXC1 controls aggressiveness of basal-like breast cancer remains to be elucidated. Here, we identify matrix metalloprotease 7 (MMP7) as a key downstream effector of FOXC1-mediated invasiveness. Expression of FOXC1 and MMP7 is significantly correlated in breast cancer samples and cell lines at both the mRNA and protein levels. Transient expression of FOXC1 in nontransformed mammary epithelial cell lines resulted in significantly increased expression of MMP7 and an MMP7-dependent increase in invasiveness. In reciprocal experiments, silencing endogenous FOXC1 in basal-like breast cancer cell lines resulted in decreased expression of MMP7 without decreased expression of other matrix metalloproteinases. We also demonstrate that elevated co-expression of FOXC1 and MMP7 is an independent predictor of patient outcome in multivariate analyses of two breast cancer patient cohorts. Together, our findings identify MMP7 as a novel mechanism through which FOXC1 may regulate the basal-like breast cancer invasive phenotype and the propensity of these cancers to metastasize. Furthermore, our findings demonstrate for the first time a correlation between MMP7 expression and basal-like breast cancers, suggesting that MMP7 may be a useful therapeutic target for treatment of this disease.

Dimerumic acid inhibits SW620 cell invasion by attenuating H₂O₂-mediated MMP-7 expression via JNK/C-Jun and ERK/C-Fos activation in an AP-1-dependent manner

Reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂) in the tumor microenvironment play important roles in tumor invasion and metastasis. Recently, ROS have been reported to cause a significant increase in the production and expression of matrix metalloproteinase (MMP)-7, which is closely correlated with metastatic colorectal cancer. The present study was undertaken to evaluate the scavenging activity of dimerumic acid (DMA) for H₂O₂ isolated from Monascus-fermented rice to investigate the inhibitory effects of DMA on the invasive potential of SW620 human colon cancer cells, and to explore the mechanisms underlying both these phenomena. Our results showed that increased MMP-7 expression due to H₂O₂ exposure was mediated by activation of mitogen-activated protein kinases (MAPKs) such as Jun N-terminal kinase (JNK), extracellular-regulated kinase (ERK), and p38 kinase. DMA pretreatment suppressed activation of H₂O₂-mediated MAPK pathways and cell invasion. Moreover, H₂O₂-triggered MMP-7 production was demonstrated via JNK/c-Jun and ERK/c-Fos activation in an activating protein 1 (AP-1)-dependent manner. Taken together, these results suggest that DMA suppresses H₂O₂-induced cell invasion by inhibiting AP-1-mediated MMP-7 gene transcription via the JNK/c-Jun and ERK/c-Fos signaling pathways in SW620 human colon cancer cells. Our data suggest that DMA may be useful in minimizing the development of colorectal metastasis. In the future, DMA supplementation may be a beneficial antioxidant to enhance surgical outcomes.

Attenuation of the Wnt/beta-catenin/TCF pathway by in vivo interferon-alpha2b (IFN-alpha2b) treatment in preneoplastic rat livers

Wnt/beta-catenin/T cell factor (TCF) pathway is activated in several types of human cancers, promoting cell growth and proliferation. Forkhead box containing protein class O (FOXO) transcription factors compete with TCF for beta-catenin binding, particularly under cellular oxidative stress conditions. Contrary to beta-catenin/TCF, beta-catenin/FOXO promotes the transcription of genes involved in cell cycle arrest and apoptosis. We have previously demonstrated that in vivo interferon-alpha2b (IFN-alpha2b) administration induces apoptosis in preneoplastic livers, a mechanism mediated by reactive oxygen species (ROS) and transforming growth factor-beta(1) (TGF-beta(1)). This study was aimed to assess the status of the Wnt/beta-catenin/TCF pathway in a very early stage of rat hepatocarcinogenesis and to further evaluate the effects of in vivo IFN-alpha2b treatment on it. We demonstrated that the Wnt/beta-catenin/TCF pathway is activated in preneoplastic rat livers. More important, in vivo IFN-alpha2b treatment inhibits Wnt/beta-catenin/TCF pathway and promotes programed cell death possibly providing a link with FOXO pathway.

Insulin-like growth factor-I receptor blockade reduces the invasiveness of gastrointestinal cancers via blocking production of matrilysin

Insulin-like growth factor-I receptor (IGF-IR) signaling is required for carcinogenicity and proliferation of gastrointestinal (GI) cancers. We have previously shown significant therapeutic activity for recombinant adenoviruses expressing dominant-negative insulin-like growth factor-I receptor (IGF-IR/dn), including suppression of tumor invasion. In this study, we sought to evaluate the mechanism of inhibition of invasion and the relationship between IGF-IR and matrix metalloproteinase (MMP) activity in GI carcinomas. We analyzed the role of IGF-IR on invasion in three GI cancer cell lines, colorectal adenocarcinoma, HT29; pancreatic adenocarcinoma, BxPC3 and gastric adenocarcinoma, MKN45, using a modified Boyden chamber method and subcutaneous xenografts in nude mice. The impact of IGF-IR signaling on the expression of MMPs and the effects of blockade of matrilysin or IGF-IR on invasiveness were assessed using recombinant adenoviruses, a tyrosine kinase inhibitor NVP-AEW541 and antisense matrilysin. Invasive subcutaneous tumors expressed several MMPs. IGF-IR/dn reduced the expression of these MMPs but especially matrilysin (MMP-7). Insulin-like growth factor (IGF) stimulated secretion of matrilysin and IGF-IR/dn blocked IGF-mediated matrilysin induction in three GI cancers. Both IGF-IR/dn and inhibition of matrilysin reduced in vitro invasion to the same degree. NVP-AEW541 also reduced cancer cell invasion both in vitro and in murine xenograft tumors via suppression of matrilysin. Thus, blockade of IGF-IR is involved in the suppression of cancer cell invasion through downregulation of matrilysin. Strategies of targeting IGF-IR may have significant therapeutic utility to prevent invasion and progression of human GI carcinomas.

Matrix metalloproteinase 7 is required for tumor formation, but dispensable for invasion and fibrosis in SMAD4-deficient intestinal adenocarcinomas

Expression of matrix metalloproteinase 7 (MMP7) is increased in the human colorectal carcinomas, and correlates with malignant progression. However, its contribution to colon cancer pathogenesis is not understood thoroughly. To investigate the roles of MMP7 in colon cancer progression, we introduced an Mmp7 knockout mutation into the cis-Apc/Smad4 mutant mouse, a model of invasive colon cancer in which SMAD4-dependent TGF-beta family signaling is inactivated. We demonstrate here that lack of MMP7 reduces the number and size of tumors in the cis-Apc/Smad4 mice. On the other hand, MMP7-deficiency does not affect the depth of tumor invasion, number of stromal fibroblasts or levels of extracellular matrix components in the tumors. These results indicate that MMP7 is required for tumor formation, but not for the invasion or fibrosis of the colon cancer whose SMAD4-dependent TGF-beta family signaling is blocked.

Evaluation of matrix metalloproteinase 7 in plasma and pancreatic juice as a biomarker for pancreatic cancer

Differentiating between periampullary carcinoma and chronic pancreatitis with an inflammatory mass is difficult. Consequently, 6% to 9% of pancreatic resections for suspected carcinoma are done inappropriately for chronic pancreatitis. Here, we test if matrix metalloproteinase 7 (MMP-7), a secreted protease frequently expressed in pancreatic carcinoma, can be measured in plasma, pancreatic, and duodenal juice, and if it can distinguish between periampullary carcinoma and chronic pancreatitis. Ninety-four patients who underwent pancreatic surgery for a (peri)pancreatic neoplasm (n = 63) or chronic pancreatitis (n = 31) were analyzed. Median plasma MMP-7 levels were significantly higher in carcinoma (1.95 ng/mL; interquartile range, 0.81-3.22 ng/mL) compared with chronic pancreatitis and benign disease (0.83 ng/mL; interquartile range, 0.25-1.21 ng/mL; P < 0.01). MMP-7 levels in pancreatic juice were higher, although not significantly, in carcinoma (62 ng/mg protein; interquartile range, 18-241 ng/mg protein) compared with chronic pancreatitis and benign disease (23 ng/mg protein; interquartile range, 8.5-99 ng/mg protein; P = 0.17). MMP-7 levels in duodenal juice were universally low. At an arbitrary cutoff of 1.5 ng/mL in plasma, positive and negative predictive values were 83% and 57%, respectively, values comparable to those of today's most common pancreatic tumor marker, carbohydrate antigen 19-9 (CA19-9; 83% and 53%, respectively). Positive and negative likelihood ratios for plasma MMP-7 were 3.35 and 0.52, respectively. The area under the receiver operating characteristic curve for MMP-7 was 0.73 (95% confidence interval, 0.63-0.84) and for CA19-9, 0.75 (95% confidence interval, 0.64-0.85). Combined MMP-7 and CA19-9 assessment gave a positive predictive value of 100%. Thus, plasma MMP-7 levels discriminated between patients with carcinoma and those with chronic pancreatitis or benign disease. The diagnostic accuracy of plasma MMP-7 alone is not sufficient to determine treatment strategy in patients with a periampullary mass, but combined evaluation of plasma MMP-7 with CA19-9 and other markers may be clinically useful.

Prognostic significance of matrix metalloproteinases-1, -2, -7 and -13 and tissue inhibitors of metalloproteinases-1, -2, -3 and -4 in colorectal cancer

Strong expression of many matrix metalloproteinases (MMPs) has been related to poor survival of colorectal cancer (CRC) patients. The expression of tissue inhibitors of metalloproteinases (TIMPs) has been associated with both a beneficial and a poor outcome and there is thus a need to further clarify the significance of MMPs and TIMPs in CRC. The prognostic significance of 4 MMPs and TIMPs in CRC was evaluated. Formalin-fixed, paraffin-embedded tissue arrayed samples of 351 patients with primary colon or rectal cancer of Dukes' stages A-D were selected for immunohistochemical staining of MMP-1, -2, -7 and -13, and TIMP-1, -2, -3 and -4. High expression of MMP-2 in the malignant epithelium as well as in the surrounding stroma was associated with reduced survival of colon cancer patients. Strong epithelial and stromal cytoplasmic staining of TIMP-3 was associated with a longer survival in rectal cancer patients, and here the interobserver variation for evaluating the degree of staining was lower than for epithelial staining. Strong stromal cytoplasmic staining of TIMP-4 predicted longer survival of rectal cancer patients. Multivariate analysis showed that stromal cytoplasmic TIMP-3 staining was the only marker of independent prognostic value. MMP-2 might be a useful prognostic marker in colon cancer, and TIMP-3 and TIMP-4 in rectal cancer, but the findings associated with stromal staining should be interpreted with some caution. Different biologic behavior or different genetic development may explain the differences between colon and rectal cancers regarding the expression of MMP-2, TIMP-3 and TIMP-4.

The carbon monoxide-releasing molecule CORM-2 inhibits the inflammatory response induced by cytokines in Caco-2 cells

BACKGROUND AND PURPOSE

Recent evidence indicates that carbon monoxide-releasing molecules (CO-RMs) exhibit potential anti-inflammatory properties. In the present study, we have investigated whether tricarbonyl dichloro ruthenium(II) dimer (CORM-2) can control the inflammatory response induced by cytokines in a human colonic epithelial cell line, Caco-2.

EXPERIMENTAL APPROACH

Caco-2 cells were preincubated with CORM-2 for 30 minutes and then stimulated with interleukin (IL)-1beta, tumor necrosis factor-alpha and interferon-gamma for different times. Gene expression was analyzed by real-time PCR. Protein expression was investigated by Western blot and ELISA. Transcription factor activation was determined by the luciferase method.

KEY RESULTS

We have shown that CORM-2 significantly decreased the mRNA expression of nitric oxide synthase-2 (NOS-2) and the production of nitrite, in Caco-2 cells stimulated with cytokines. IL-8, IL-6 and metalloproteinase-7 (MMP-7) mRNA and protein were also significantly reduced by CORM-2. Time-course and small interfering RNA studies suggest that inhibition of IL-6 plays a role in the regulation of MMP-7 expression by CORM-2. These effects of CORM-2 can be dependent on the modulation of nuclear factor-kappaB (NF-kappaB), activator protein-1, CCAT/enhancer binding protein and the phosphorylated forms of NF-kappaB inhibitory protein-alpha, c-Jun N-terminal protein kinase 1/2, p38 and extracellular signal-regulated kinase 1/2.

CONCLUSIONS AND IMPLICATIONS

CORM-2 can regulate a number of genes relevant in intestinal inflammation and cancer progression. These findings provide new insights into the anti-inflammatory properties and potential applications of this class of compounds.

Relationship between molecular markers and endoscopic findings in laterally spreading tumors

BACKGROUND AND AIM

Characteristic clinicopathological features of laterally spreading tumors (LSTs) have been reported by endoscopists; however, only a few studies have been conducted on the biological features. These studies were not fully associated with the endoscopic findings of LSTs. The aim of this study was to estimate the biological features of each type of endoscopic finding of LST using two molecular markers, matrix metalloproteinase-7 (MMP-7) and beta-catenin.

METHODS

Expression of the molecular markers and the endoscopic findings were compared in 22 LSTs and 14 subpedunculated polyps. MMP-7 and beta-catenin were immunostained. Three types of representative endoscopic findings of LST were defined as segments in LSTs. They were 15 granular segments, seven large nodular segments, and seven flat segments that corresponded to the area composed of aggregates of similar size granules, large nodules of diameter more than 10 mm, and a flat surface with no granule, respectively.

RESULTS

Expression of MMP-7 and coexpression of MMP-7 and beta-catenin were higher in large nodular segments than in granular segments (P < 0.0167). Among the three types of segments, flat segments showed the highest expression densities of beta-catenin accumulated in the nucleus. Large nodular segments and subpedunculated polyps showed similar expression patterns for the molecular markers.

CONCLUSIONS

This study provides new and important information on the relationship between the molecular markers and endoscopic findings of LSTs.

Genetic polymorphisms of MMP1, MMP3 and MMP7 gene promoter and risk of colorectal adenoma

Background

Matrix metalloproteinases (MMP) have been shown to play a role in colorectal cancer (CRC). More recently, MMP1, MMP3 and MMP7 functional gene promoter polymorphisms have been found to be associated with CRC occurrence and prognosis. To document the role of MMP polymorphisms in the early step of colorectal carcinogenesis, we investigated their association with colorectal adenoma risk in a case-control study comprising 295 patients with large adenomas (LA), 302 patients with small adenomas (SA) and 568 polyp-free (PF) controls.

Methods

Patients were genotyped using automated fragment analysis for MMP1 -1607 ins/del G and MMP3 -1612 ins/delA (MMP3.1) polymorphisms and allelic discrimination assay for MMP3 -709 A/G (MMP3.2) and MMP7 -181 A/G polymorphisms. Association between MMP genotypes and colorectal adenomas was first tested for each polymorphism separately and then for combined genotypes using the combination test. Adjustment on relevant variables and estimation of odds ratios were performed using unconditional logistic regression.

Results

No association was observed between the polymorphisms and LA when compared to PF or SA. When comparing SA to PF controls, analysis revealed a significant association between MMP3 -1612 ins/delA polymorphism and SA with an increased risk associated with the 6A/6A genotype (OR = 1.67, 95%CI: 1.20–2.34). Using the combination test, the best association was found for MMP3.1-MMP1 (p = 0.001) with an OR of 1.88 (95%CI: 1.08–3.28) for the combined genotype 2G/2G-6A/6A estimated by logistic regression.

Conclusion

These data show a relation between MMP1 -1607 ins/del G and MMP3 -1612 ins/delA combined polymorphisms and risk of SA, suggesting their potential role in the early steps of colorectal carcinogenesis.

Matrilysin over-expression in MCF-7 cells enhances cellular invasiveness and pro-gelatinase activation

Matrilysin (MMP-7) is over-expressed in various cancers and is thought to play important roles in tumor invasion and metastasis. However, the function of MMP-7 in breast cancer remains unclear. We therefore examined the expression of the MMP-7 gene in breast cancer (MCF-7) cells and the effect of its over-expression on cellular invasion. We transfected human MMP-7 into MCF-7 cells and selected clones that stably over-expressed the MMP-7 gene. The in vitro invasiveness of MCF-7 cells was quantified by use of the Matrigel invasion assay. Expression of MMP-7 mRNA was analyzed by quantitative RT-PCR. MMP secretion and activation were detected by gelatin zymography. We found that MMP-7-expressing clones had significantly increased invasion (P < 0.001), with increased MMP-7 expression and gelatinase activation as compared to the vector controls. We conclude that MMP-7 over-expression correlates with breast cancer in vitro invasiveness and that MMP-7 may promote invasion by increasing the secretion and activation of proMMP-2 and proMMP-9.

Gadd45a regulates matrix metalloproteinases by suppressing DeltaNp63alpha and beta-catenin via p38 MAP kinase and APC complex activation

The p53-regulated growth arrest and DNA damage-inducible gene product Gadd45a has been recently identified as a key factor protecting the epidermis against ultraviolet radiation (UVR)-induced skin tumors by activating p53 via the stress mitogen-activated protein kinase (MAPK) signaling pathway. Herein we identify Gadd45a as an important negative regulator of two oncogenes commonly over-expressed in epithelial tumors: the p53 homologue DeltaNp63alpha and beta-catenin. DeltaNp63alpha is one of the several p63 isoforms and is the predominant species expressed in basal epidermal keratinocytes. DeltaNp63alpha lacks the N-terminal transactivation domain and behaves as a dominant-negative factor blocking expression of several p53-effector genes. DeltaNp63alpha also associates with and blocks activation of the adenomatous polyposis coli (APC) destruction complex that targets free cytoplasmic beta-catenin for degradation. While most beta-catenin protein is localized to the cell membrane and is involved in cell-cell adhesion, accumulation of free cytoplasmic beta-catenin will translocate into the nucleus where it functions in a bipartite transcription factor complex, whose targets include invasion and metastasis promoting endopeptidases, matrix metalloproteinases (MMP). We show that Gadd45a not only directly associates with two components of the APC complex, namely protein phosphatase 2A (PP2A) and glycogen synthase kinase 3beta (GSK3beta) but also promotes GSK3beta dephosphorylation at Ser9, which is essential for GSK3beta activation, and resultant activation of the APC destruction complex. We demonstrate that lack of Gadd45a not only prevents DeltaNp63alpha suppression and GSK3beta dephosphorylation but also prevents free cytoplasmic beta-catenin degradation after UV irradiation. The inability of Gadd45a-null keratinocytes to suppress beta-catenin may contribute to the resulting observation of increased MMP expression and activity along with significantly faster keratinocyte migration in Matrigel in vitro and accelerated wound closure in vivo. Furthermore, epidermal keratinocytes treated with p38 MAPK inhibitors, both in vivo and in vitro, behave very similarly to Gadd45a-null keratinocytes after UVR. Similarly, Trp53-null mice are unable to attenuate DeltaNp63alpha expression in epidermal keratinocytes after such stress. These findings demonstrate a dependence on Gadd45a-mediated p38 MAPK and p53 activation for proper modulation of DeltaNp63alpha, GSK3beta, and beta-catenin after irradiation. Taken together, our results indicate that Gadd45a is able to repress DeltaNp63alpha, beta-catenin, and consequently MMP expression by two means: by maintaining UVR-induced p38 MAPK and p53 activation and also by associating with the APC complex. This implicates Gadd45a in the negative regulation of cell migration, and invasion.

Pharmacological inhibition of FGF receptor signaling inhibits LNCaP prostate tumor growth, promatrilysin, and PSA expression

Previously we have shown that the matrix metalloproteinase matrilysin (MMP-7) is overexpressed in human prostate cancers compared with normal epithelium. However, the mechanism for this overexpression is not understood. Human prostate fibroblasts have been shown to express certain fibroblast growth factors (FGFs), including FGF-1. Evidence from our laboratory and others has indicated that FGFs can regulate the expression of certain matrix metalloproteinases, including matrilysin. The goal of this study was to determine whether pharmacological inhibition of FGFR signaling would alter LNCaP tumor growth as well as expression of promatrilysin when LNCaP cells were co-injected subcutaneously with human prostate fibroblasts into athymic nude mice. For these inhibitor studies, AG1-X2 beads were coated with the pharmacological FGFR inhibitor SU5402 and were co-injected along with LNCaP and human prostate fibroblast cells (PF). Mice injected with LNCaP/PF and LNCaP/PF/beads alone demonstrated significant tumor growth, whereas mice injected with LNCaP/PF/SU5402-coated beads showed a significant decrease in tumor volume and weight. Immunohistochemical analysis showed that significant promatrilysin expression in tumors was inhibited by the FGFR inhibitor SU5402. Serum prostate-specific antigen (PSA) and promatrilysin levels were measured by enzyme-linked immunosorbent assay. The mice injected with LNCaP/PF and LNCaP/PF/beads expressed promatrilysin and serum PSA levels that were inhibited by co-injecting with SU5402. Therefore, pharmacological inhibition of FGF receptor signaling results in a decrease in the growth of LNCaP tumors generated subcutaneously by co-injecting LNCaP cells and human prostate fibroblasts. The inhibition in tumor growth was correlated with a decrease in tumor promatrilysin expression and a decrease in serum promatrilysin and PSA.

Association of ets-related transcriptional factor E1AF expression with tumour progression and overexpression of MMP-1 and matrilysin in human colorectal cancer

Expression of E1AF/PEA3 (ETV4), an ets family transcription factor, has been implicated in the invasive potential of several cancer cell lines through induction of matrix metalloproteinase (MMP) expression. The aim of this study was to examine E1AF mRNA expression and to determine whether it is correlated with progression of, and/or MMP expression in, human colorectal cancer. Using the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), 100 colorectal cancer tissues were analysed for E1AF mRNA expression. Expression of ER81 (ETV1) and ERM (ETV5), the other two members of the PEA3 subfamily, and Ets-1 and Ets-2 was also analysed. The results were correlated with clinicopathological characteristics and MMP expression. Immunohistochemical analysis and an in vitro invasion assay were also performed. E1AF mRNA expression was detected in 62% of the 100 colorectal cancer tissues, but was undetectable or only faintly detected in adjacent non-tumour tissues. E1AF mRNA was detected in all of the ten liver metastases from colorectal cancers. E1AF expression correlated significantly with depth of invasion, lymphatic and venous invasion, lymph node and distant metastasis, advance in pathological tumour-node-metastasis stage, and recurrence. Patients with E1AF-positive tumours had significantly shorter overall and disease-free survival periods than did those with E1AF-negative tumours (p < 0.0001 and p < 0.0001, respectively). E1AF expression retained its significant predictive value for overall and disease-free survival in multivariate analysis that included conventional clinicopathological factors (p = 0.0066 and p = 0.0109, respectively). Among the MMPs analysed, expression of MMP-1 and matrilysin correlated significantly with E1AF expression. In contrast, expression of ER81 and ERM did not correlate with clinicopathological characteristics or the expression of these MMPs. Immunohistochemical expression of E1AF was predominantly observed at the invasive front, where the expression of MMP-1 and matrilysin and nuclear beta-catenin expression were often co-localized. Antisense E1AF-transfected HT-29 colon cancer cells expressed reduced levels of MMP-1 and matrilysin and were less invasive in vitro than neo-transfected HT-29 cells. The results of this study suggest that E1AF, the expression of which is closely correlated with the expression of MMP-1 and matrilysin, plays a key role in the progression of colorectal cancer.

Association of trypsin expression with tumour progression and matrilysin expression in human colorectal cancer

Overexpression of the matrix serine protease (MSP) trypsin has been implicated in tumour growth, invasion, and metastasis. The objective of this study was to clarify the clinicopathological and prognostic significance of trypsin expression in colorectal cancer. This study analysed the association between immunohistochemically detected trypsin expression in colorectal cancer and clinicopathological characteristics, and investigated whether trypsin is a predictor of recurrence and/or survival. Trypsin immunoreactivity was more intense at the invasive front than in the superficial part of the tumour. Sections with immunostaining signals in more than 30% of carcinoma cells at the invasive front, which were observed in 48 cases (48%), were judged to be positive for trypsin. Trypsin positivity was significantly correlated with depth of invasion, lymphatic and venous invasion, lymph node and distant metastasis, advanced pathological tumour-node-metastasis (TNM) stage, and recurrence. Patients with trypsin-positive carcinoma had significantly shorter overall and disease-free survival periods than did those with trypsin-negative carcinoma. Trypsin retained its significant predictive value for overall and disease-free survival in multivariate analysis that included conventional clinicopathological factors. It is well known that trypsin activates matrilysin (matrix metalloproteinase-7), which plays an important role in colorectal cancer progression. Patients with concordant overexpression of trypsin and matrilysin at the invasive front, in which they were often co-localized, had the worst prognosis. Trypsinogen-1-transfected HCT116 colon cancer cells showed not only trypsin activity, but also active matrilysin activity and were more invasive in vitro than mock-transfected HCT116 cells. These results suggest that trypsin plays a key role in the progression of colorectal cancer. Detection of trypsin expression as well as matrilysin is useful for the prediction of recurrence in and poor prognosis of colorectal cancer patients.

Matrilysin stimulates DNA synthesis of cultured vascular endothelial cells and induces angiogenesis in vivo

Matrilysin produced by human colon cancer cells may be involved in the progression and metastasis of cancer. In the present study, we investigated the association of matrilysin with angiogenesis. One microgram of recombinant matrilysin is confirmed to have increased [3H]-thymidine uptake in human umbilical vein endothelial cells. Then we used micro encapsulation and a mouse hemoglobin enzyme-linked immunosorbent assay system for in vivo quantitation of angiogenesis with BALB/c nu/nu athymic mice. Hundred micrograms of recombinant matrilysin induced angiogenesis to the same degree as 10 microg of basic fibroblast growth factor (bFGF). Angiogenesis was observed at the site implanted with human colon cancer WiDr cells in agarose micro beads. This was inhibited by subcutaneous injection of matrilysin-specific antisense oligonucleotide significantly by 53%. In conclusion, matrilysin may be associated with angiogenesis of human colon cancer through the direct proliferative action on endothelial cells.

Interleukin-1beta-induced promatrilysin expression is mediated by NFkappaB-regulated synthesis of interleukin-6 in the prostate carcinoma cell line, LNCaP

Previously, our laboratory showed that interleukin-1beta (IL-1beta) secreted by lipopolysaccharide-activated monocytes induces promatrilysin expression in the prostate carcinoma cell line, LNCaP. We now demonstrate that IL-1beta-induced promatrilysin expression is mediated by an indirect mechanism that requires nuclear factor Kappa B (NFkappaB)-dependent synthesis of IL-6. Inhibition of protein synthesis with cycloheximide blocked IL-1beta-mediated induction of matrilysin mRNA suggesting that synthesis of one or more additional factors is required for IL-1beta-induced promatrilysin protein expression. Blockage of NFkappaB transactivation activity abrogated IL-1beta-induced promatrilysin expression to baseline levels suggesting that NFkappaB transactivation activity is necessary. Inhibition of IL-6 activity attenuated IL-1beta-induced promatrilysin, but not NFkappaB transactivation activity indicating that IL-6 acts downstream of NFkappaB in potentiation of IL-1beta-mediated promatrilysin expression. Inhibition of protein synthesis with cycloheximide did not alter IL-6-induced induction of matrilysin mRNA indicating that, contrary to the mechanism by which IL-1beta regulates promatrilysin expression, IL-6-mediated matrilysin mRNA expression does not require new protein synthesis. Transient transfection with dominant negative STAT3 inhibited IL-1beta- and IL-6-induced promatrilysin. These data provide evidence that NFkappaB-mediated IL-6 synthesis is required for IL-1beta-induced promatrilysin expression, and IL-6 signaling through STAT3 plays a role in IL-1beta-induced promatrilysin expression.

Clinicopathologic and prognostic significance of matrilysin expression at the invasive front in human colorectal cancers

Matrix metalloproteinases (MMPs) have been implicated in tumor progression. Matrilysin, one of the matrix metalloproteinases, is frequently overexpressed in gastrointestinal cancers. The aim of our study was to assess the validity of matrilysin as a prognostic marker of colorectal cancers. Matrilysin expression was immunohistochemically analyzed using formalin-fixed, paraffin-embedded specimens from 113 colorectal cancer patients who had undergone curative surgery. The lumenal surface of neoplastic glands in the superficial layer was apically stained, while the cytoplasm of cancer cells at the invasive front was diffusely stained for matrilysin. Sections with immunostaining signals in more than 30% of carcinoma cells at the invasive front, which were observed in 47 (42%) cases, were judged as being positive for matrilysin. Matrilysin positivity was significantly correlated with the depth of invasion, lymph node metastasis, lymphatic invasion, advanced Dukes' stage and poor outcome. Patients with matrilysin-positive cancer had a significantly shorter overall survival time than those with matrilysin-negative cancer. For patients with intermediate invasive tumor (T2 or T3), only matrilysin was a significant prognostic variable for predicting overall survival in multivariate analysis. Matrilysin expression at the invasive front could be an important marker, predicting an unfavorable prognosis after surgical treatment in patients with colorectal cancer.

Association of matrilysin mRNA expression with K-ras mutations and progression in pancreatic ductal adenocarcinomas

The matrix metalloproteinase matrilysin has been implicated in the progression of gastrointestinal and other cancers. The aim of this study was to examine matrilysin mRNA expression and determine whether it is correlated with K-ras mutations and/or progression of pancreatic carcinoma. Using the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we analyzed 11 pancreatic cancer cell lines and 70 pancreatic adenocarcinoma tissues for matrilysin mRNA expression. The results were correlated with clinicopathological characteristics and K-ras mutations. Significant amounts of matrilysin mRNA were detected in six of the eight cell lines with K-ras mutations but not in the three cell lines with wild-type K-ras. Matrilysin mRNA was detected in 57 (81.4% ) of the 70 tumor tissues and in all of the eight liver metastases, but not in any of the adjacent non-tumorous tissues. Matrilysin expression was significantly correlated with the size of tumor, tumor spreading, lymph node metastasis, advanced pathologic tumor-node- metastasis stage and K-ras mutations. The relative amounts of matrilysin mRNA in tumor tissues increased with increase in tumor stage and were highest in liver metastatic tumor tissues. Our results suggest that matrilysin, the expression of which is correlated with K-ras mutations, plays a key role in tumor growth and progression of pancreatic carcinoma.

Low-dose retinoic acid enhances in vitro invasiveness of human oral squamous-cell-carcinoma cell lines

Retinoids inhibit the proliferation of several types of tumour cells, and are used for patients with several malignant tumours. In this study, we examined the effect of retinoic acids (RAs) on the invasive potentials of the oral squamous cell carcinoma (SCC) cells, BHY and HNt. BHY cells expressed all of retinoid nuclear receptors (RARalpha, beta, gamma, and RXRalpha) and cytoplasmic retinoic acid binding proteins (CRABP1 and CRABP2). HNt cells lacked the expression of RARbeta, but expressed other nuclear receptors and CRABPs. All-trans retinoic acid (ATRA) and 13-cis retinoic acid (13-cisRA) (10(-6)and 10(-7)M) inhibited the growth of the cells, but low-dose ATRA and 13-cisRA (10(-8)M) marginally affected the growth of the cells. Surprisingly, low-dose RAs enhanced the activity of tissue-type plasminogen activator (tPA), and activated pro-matrix metalloproteinases (proMMP2 and proMMP9). Activation of proMMP2 and proMMP9 was inhibited by aprotinin, a serine-proteinase, tPA inhibitor. Furthermore, low-dose RAs enhanced the in vitro invasiveness of BHY cells. These results indicate that low-dose RAs enhances the in vitro invasiveness of oral SCC cells via an activation of proMMP2 and proMMP9 probably mediated by the induction of tPA.

Regulation of matrilysin in the rat uterus

Matrilysin was first discovered in the involuting rat uterus; it has also been known as uterine metalloproteinase, putative metalloproteinase (Pump-1), and matrix metalloproteinase 7 (MMP-7). It is the smallest member (28 kDa) of a family of 15 MMPs that together are able to degrade most of the macromolecules of the extracellular matrix. This family is briefly reviewed; all members are zinc metalloproteinases that occur in zymogen form with the active site zinc blocked by cysteine. Matrilysin can degrade a wide range of gelatins, proteoglycans, and glycoproteins of the matrix and can activate several other MMPs including collagenase. With respect to the uterus, matrilysin is localized to epithelial cells and varies in amount with the estrus cycle and is found in high levels during postpartum involution. There is evidence for a role in the last stage of cervical ripening and immediately postpartum. Induction of premature delivery by onapristone and prostaglandin E2 advances these changes in matrilysin. Regulation of the enzyme levels in the uterus are considered from four viewpoints: control of protein synthesis (particularly in response to hormones), activation of the proenzyme to functional protease, retention of enzyme by binding to matrix components such as heparan sulfate, and inhibition by natural inhibitors such as tissue inhibitor of metalloproteinases (TIMPs) and alpha 2-macroglobulin.

Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human pancreatic adenocarcinomas: clinicopathologic and prognostic significance of matrilysin expression

PURPOSE

A disruption in the balance between the matrix metalloproteinases (MMPs) and their natural inhibitors, tissue inhibitors of metalloproteinases (TIMPs), has been implicated in the progression of many types of cancer. The aim of this study was to determine whether a specific MMP or TIMP has clinicopathologic and prognostic significance in pancreatic carcinoma.

PATIENTS AND METHODS

Using immunohistochemistry, we analyzed 70 pancreatic ductal adenocarcinoma tissues for expression of MMP-1, MMP-2, MMP-3, MMP-7 (matrilysin), MMP-9, MT1-MMP, TIMP-1, and TIMP-2. The results were matched with clinicopathologic characteristics and patients' survival. The effects of the suppression of a specific MMP on in vitro invasiveness of pancreatic carcinoma cells were also examined.

RESULTS

Expression of MMP-1, MMP-2, MMP-3, matrilysin, MMP-9, MT1-MMP, TIMP-1, and TIMP-2 was detected in either tumor cells or tumor stromal cells, or in both components, at varying frequencies. Among MMPs, matrilysin showed a unique distribution in the tumor nests; its expression was usually most pronounced at the invasive front of the tumors. Sections with immunostaining signals in more than 30% of carcinoma cells at the invasive front, which were observed in 40 cases (57%), were judged to be positive for matrilysin. Matrilysin positivity was significantly correlated with pT, pN, and pM categories and with more advanced pathologic tumor-node-metastasis stages. Patients with matrilysin-positive carcinoma had a significantly shorter overall survival time than did those with matrilysin-negative carcinoma. Matrilysin was a significant independent prognostic factor for overall survival in multivariate analysis. In contrast, there was no correlation between the presence of other MMPs or TIMPs and clinicopathologic characteristics, nor was the presence of individual MMPs or TIMPs related to survival. Antisense matrilysin-transfected CFPAC-1 cells expressed reduced levels of matrilysin and demonstrated a similar growth potential but were less invasive in vitro compared with neotransfected CFPAC-1 cells.

CONCLUSION

Our results suggest that matrilysin may play a key role in progression of pancreatic carcinoma and thereby contribute to a poor prognosis. Because different synthetic MMP inhibitors affect different types of MMPs to a different degree, examination of the expression of MMPs, especially that of matrilysin, may serve as an indicator for selecting the most effective MMP inhibitor.

Promatrilysin expression is induced by fibroblast growth factors in the prostatic carcinoma cell line LNCaP but not in normal primary prostate epithelial cells

BACKGROUND

It has been determined that prostate cancer cells overexpress the matrix metalloprotease matrilysin (MMP-7), but the factors regulating this expression have not been identified. Fibroblast growth factors (FGF), which are expressed in the prostate, might participate in paracrine regulation of matrilysin expression by prostate cancer cells.

METHODS

We tested the ability of recombinant FGF proteins and prostate fibroblast-conditioned media (PFCM) to induce promatrilysin expression in the prostate carcinoma cell line, LNCaP, and in normal prostate epithelial (PrEC) cells. We also characterized prostate fibroblast FGF expression by reverse transcriptase-polymerase chain reaction (RT-PCR). An inhibitor of FGF receptor activation (SU5402) was used to determine the role of FGF proteins in the induction of promatrilysin expression by PFCM.

RESULTS

Recombinant FGF-1, FGF-2, FGF-9, FGF-10, and PFCM significantly induced promatrilysin expression in LNCaP cells but not in PrEC cells. Prostate fibroblasts express mRNAs for these FGF proteins, and inhibition of LNCaP cell FGF receptors with SU5402 substantially reduced the induction of promatrilysin expression by PFCM.

CONCLUSIONS

Stromally expressed FGF proteins induce promatrilysin expression in a prostate carcinoma cell, and may provide a mechanism for the overexpression of promatrilysin observed in prostate cancer.

beta-catenin regulates the expression of the matrix metalloproteinase-7 in human colorectal cancer

Most colorectal cancers have loss of function mutations in the adenomatosis polyposis coli (APC) tumor suppressor gene. This leads to accumulation of beta-catenin, which together with the DNA binding protein TCF-4 functions as a transcriptional activator. Recently defined target genes are c-myc and cyclin D1, linking the APC gene defect to the capacity for autonomous proliferation of colon tumors. Here we report the identification of the matrix metalloproteinase MMP-7 as another target gene of beta-catenin/TCF-4. MMP-7 is overexpressed in 80% of human colorectal cancers and known to be an important factor for early tumor growth, with a potential function also for later progression steps, like invasion and metastasis. Our results explain the high percentage of MMP-7 overexpression in colon tumors. Moreover they indicate that defects in the APC tumor suppressor gene may also have an influence on later steps of colon tumor progression.

Matrix metalloproteinase inhibition. From the Jurassic to the third millennium

A brief historical introduction to the matrix metalloproteinase (MMP) field, which began in 1962, is followed by an overview of the inhibition of these proteases by natural inhibitors such as alpha 2 macroglobulin and the TIMPs (tissue inhibitors of metalloproteinases) and by synthetic inhibitors, which are largely chelating agents. The latter include thiol, alkylcarbonyl, phosponamidate and hydroxamate compounds, as well as the tetracyclines. A review of the most recent progress concludes with prognostications as to where the field may be going next.

Expression of matrix metalloproteinases in human glioma cell lines in the presence of IL-10

Matrix metalloproteinases have been implicated to play a vital role in glioma invasion as they degrade extracellular matrix to facilitate the subsequent migration of tumor cells into the surrounding brain tissue. The cytokine Interleukin-10 (IL-10) was detected recently in glial tumors in vivo. Expression of specific IL-10 mRNA as well as blood serum levels of IL-10 in glioma patients increased with malignancy suggesting a functional role of IL-10 in glioma progression. Moreover, glioma cell migration in vitro was enhanced in the presence of IL-10. We therefore investigated the expression of the matrix metalloproteinases (MMPs) stromelysin-1 (MMP-3), 72-kDa collagenase (MMP-2), 92-kDa collagenase (MMP-9), matrilysin (MMP-7) and the human macrophage metalloelastase (MMP-12). In addition, a possible relation between exposure of glioma cells to IL-10 and invasiveness of these cells due to MMP expression was analyzed. Experiments with Matrigel coated Boyden chambers revealed a pronounced dose dependent effect of IL-10 on glioma invasiveness. The synthetic MMP-inhibitor Marimastat markedly reduced cell invasion in the Boyden chambers confirming the significance of MMPs in the process of invasion. Subsequently, the expression level of MMPs and the serine protease uPA was investigated in 7 glioma cell lines (U373, GaMG, U251, GHE, SNB19, U138 and D54) by RT-PCR. In all but one cell line no enhancement of MMP expression by IL-10 was detected. Matrilysin in U373 cells was the only protease found to be upregulated in the presence of IL-10 dependent on cell density. The present data suggest that IL-10 related effects on the invasive properties of the cell lines are not directly mediated by an upregulation of matrix metalloproteinase expression.

Expression of matrix metalloproteinases in human glioma cell lines in the presence of IL-10

Matrix metalloproteinases have been implicated to play a vital role in glioma invasion as they degrade extracellular matrix to facilitate the subsequent migration of tumor cells into the surrounding brain tissue. The cytokine Interleukin-10 (IL-10) was detected recently in glial tumors in vivo. Expression of specific IL-10 mRNA as well as blood serum levels of IL-10 in glioma patients increased with malignancy suggesting a functional role of IL-10 in glioma progression. Moreover, glioma cell migration in vitro was enhanced in the presence of IL-10. We therefore investigated the expression of the matrix metalloproteinases (MMPs) stromelysin-1 (MMP-3), 72-kDa collagenase (MMP-2), 92-kDa collagenase (MMP-9), matrilysin (MMP-7) and the human macrophage metalloelastase (MMP-12). In addition, a possible relation between exposure of glioma cells to IL-10 and invasiveness of these cells due to MMP expression was analyzed. Experiments with Matrigel coated Boyden chambers revealed a pronounced dose dependent effect of IL-10 on glioma invasiveness. The synthetic MMP-inhibitor Marimastat markedly reduced cell invasion in the Boyden chambers confirming the significance of MMPs in the process of invasion. Subsequently, the expression level of MMPs and the serine protease uPA was investigated in 7 glioma cell lines (U373, GaMG, U251, GHE, SNB19, U138 and D54) by RT-PCR. In all but one cell line no enhancement of MMP expression by IL-10 was detected. Matrilysin in U373 cells was the only protease found to be upregulated in the presence of IL-10 dependent on cell density. The present data suggest that IL-10 related effects on the invasive properties of the cell lines are not directly mediated by an upregulation of matrix metalloproteinase expression.

Matrilysin-specific antisense oligonucleotide inhibits liver metastasis of human colon cancer cells in a nude mouse model

Human colon cancer frequently develops liver metastasis. Matrilysin (MMP-7), the smallest member of the matrix metalloproteinase (MMP) family, is commonly produced by human colon carcinoma cells and has been suggested to be involved in the progression and metastasis of this type of cancer. In the present study, we tested the effect of a matrilysin-specific antisense phosphorothioate oligonucleotide on liver metastasis of the human colon carcinoma cell line WiDr in nude mice. In culture, the antisense oligonucleotide moderately inhibited the secretion of matrilysin by WiDr cells. Injection of WiDr cells into the spleen of nude mice produced many metastatic tumor nodules in the liver. When the antisense oligonucleotide was injected daily into the mice for 11 days, the formation of the metastatic tumor nodules was strongly inhibited in a dose-dependent manner. An inhibition of liver metastasis of over 70% was obtained at a dose of 120 micrograms of the oligonucleotide per mouse. The antisense oligonucleotide did not inhibit tumor growth in spleen and in liver. A scrambled control oligonucleotide had no effect on liver metastasis of WiDr cells. Our results demonstrate an important role of matrilysin in liver metastasis of human colon cancer and the therapeutic potential of matrilysin antisense oligonucleotides for the prevention of metastasis.

Relation of matrilysin messenger RNA expression with invasive activity in human gastric cancer

Matrilysin is a member of the matrix metalloproteinase gene family which is believed to play an important role in tumor progression. Expression of matrilysin mRNA was examined by reverse transcription-polymerase chain reaction combined with Southern blot analysis in 46 human primary gastric cancers. Overexpression of matrilysin was observed in 28 (61%) of gastric cancer tissues. The positive expression ratio of matrilysin was significantly higher in the gastric cancers of subserosa or beyond it than in those within the submucosal layer. Immunohistochemical study with anti-matrilysin monoclonal antibody revealed that matrilysin was mainly expressed on cancer cells but not or very weakly expressed on other cells. In addition, an activated form of matrilysin detected by zymographic analysis was observed in gastric cancer tissues whereas none was detected in non-cancerous tissues, suggesting that matrilysin may directly and powerfully contribute to the invasion step of human gastric cancer. In order to gain more insight into the relationship of this metalloproteinase to invasive activity, we also modulated the expression of matrilysin in gastric cancer cells by DNA transfection using gastric cancer cell lines. Overexpression of matrilysin rendered the gastric cancer cells more invasive in vitro. Concomitant with clinical investigations, matrilysin may be an important metalloproteinase in the progression of gastric cancer.

Expression of matrilysin in vascular endothelial cells adjacent to matrilysin-producing tumors

Matrilysin is believed to play important roles in tumor progression and metastasis. In the present study, we analyzed matrilysin-producing cells in various human cancer tissues by immunohistochemistry and in situ hybridization. Tumor cells in colorectal carcinomas, pancreatic carcinomas, transitional-cell carcinomas of the kidney and small-cell lung carcinomas were frequently positive for matrilysin. In addition, we found that endothelial cells of arterioles and venules adjacent to matrilysin-positive tumors expressed matrilysin mRNA and protein. The endothelial cells adjacent to matrilysin-negative tumors and those in normal tissues were negative for matrilysin. Furthermore, analyses by casein zymography, Western blotting and RT-PCR showed that matrilysin was weakly expressed by cultured human umbilical vein endothelial cells. Our results suggest that the expression of matrilysin in vascular endothelial cells and in tumor cells may be regulated by common soluble factors, and that endothelial cell-derived matrilysin may contribute to tumor angiogenesis and tumor metastasis.

Stromelysin-3 expression promotes tumor take in nude mice

Stromelysin-3 (ST3) is a matrix metalloproteinase expressed in human carcinomas in ways suggesting that it may play a role in tumor progression. To test this possibility, we have performed gene transfer experiments using both anti-sense and sense ST3 expression vectors, and malignant cells either expressing (NIH 3T3 fibroblasts) or not (MCF7 epithelial cells) endogenous ST3. We have compared the ability of parental and transfected cells to cause subcutaneous tumor development in nude mice. 3T3 cells expressing anti-sense ST3 RNA showed reduced tumorigenicity, and MCF7 cells expressing mouse or human ST3 were associated with reduced tumor-free period leading to a significant increased tumor incidence(P<10(-4)). However, once established, the ST3 expressing tumors did not grow faster than those obtained with the parental MCF7 cell line. In addition, tumors obtained after sub-cutaneous injection of ST3-expressing or nonexpressing cells did not exhibit obvious histological differences, and careful examination did not reveal any local invasive tissue areas nor systemic metastases. These in vivo observations were in agreement with those obtained in vitro showing that ST3 expression did not modify proliferative nor invasive properties of transfected cells. Altogether, these results indicate that ST3 expression promotes tumor take in nude mice, presumably by favoring cancer cell survival in a tissue environment initially not permissive for tumor growth. These findings represent the first experimental evidence showing that ST3 can modulate cancer progression.

Stromelysin-3 in the biology of the normal and neoplastic mammary gland

Stromelysin-3 (ST3) is an extracellular proteinase predominantly expressed in fibroblasts. The particular structural features and in vitro functions of this molecule suggest it could be the first member of a new subgroup of the matrix metalloproteinase family. ST3 is transiently expressed during mammary gland post-weaning involution, embryonic implantation, various organogeneses, and during amphibian metamorphosis. Moreover, ST3 is expressed in a panel of human invasive carcinomas including breast, colon, and head and neck carcinomas. Almost all ST3-expressing tissues show intense extracellular matrix remodeling activities including the loss of basement membrane integrity. Thus, either directly, or indirectly in association with other proteinases, ST3 might be involved in tissue remodeling processes occurring in both physiological and pathological processes. In vitro and in vivo studies using malignant cells stably transfected in such a way as to modulate their ST3 expression levels indicate that ST3 modifies neither cell proliferation nor invasive properties, but rather favors tumor cell survival in host tissues. This hypothesis is consistent with clinical data showing that ST3 expression could be predictive of tumor progression leading to metastases.

The integrin alpha 6 beta 4 and the biology of carcinoma

The integrin family of adhesion receptors plays a major role in epithelial organization and function. Moreover, the altered expression and function of specific integrins most likely contributes significantly to carcinoma progression. The integrin alpha 6 beta 4, the focus of this review, is a receptor for several members of the laminin family and is preferentially expressed at the basal surface of most epithelia, where it contributes to basement membrane interactions. Mounting evidence suggests that the alpha 6 beta 4 integrin plays a key role in carcinoma cell biology. Several histopathological studies have established a correlation between alpha 6 beta 4 integrin expression and tumor progression. The importance of alpha 6 beta 4 expression in tumors in underscored by the findings that invading fronts of several carcinomas are enriched in the expression of alpha 6 beta 4 integrin ligands, such as laminin-1 and laminin-5. The participation of the alpha 6 beta 4 integrin in invasion is supported further by in vitro functional studies using carcinoma cells that have been transfected with the beta 4 cDNA. The mechanisms by which alpha 6 beta 4 contributes to tumor progression are probably related to its mechanical and signaling properties and are currently under intense study.

Activation of the E-cadherin/catenin complex in human MCF-7 breast cancer cells by all-trans-retinoic acid

All-trans-retinoic acid (RA), like insulin-like growth factor I (IGF-I) and tamoxifen, inhibit invasion of human MCF-7/6 mammary cancer cells in vitro. For tamoxifen and for IGF-I, activation of the invasion-suppressor function of the E-cadherin/catenin complex was shown to be the most probable mechanism of the anti-invasive action. We did a series of experiments to determine whether the anti-invasive effect of RA also implicated the invasion-suppressor E-cadherin/catenin complex. Human MCF-7/6 mammary and HCT-8/R1 colon cancer cells, both with a dysfunctional E-cadherin/catenin complex, were treated with RA and the function of the complex was evaluated through Ca(2+)-dependent fast aggregation. Fast aggregation of both MCF-7/6 and HCT-8/R1 cells was induced by 1 microM RA. This effect was abolished by antibodies against E-cadherin. RA-induced fast aggregation was not sensitive to cycloheximide, tyrosine kinase inhibitors or antibodies against IGF-I or against the IGF-I receptor. RA did not stimulate IGF-I receptor phosphorylation or alter the E-cadherin/catenin complex, as evidenced by immunoprecipitation. RA up-regulates the function of the invasion-suppressor complex E-cadherin/catenin. Its action mechanism is different from that of IGF-I. RA may act as an anti-invasive agent with unique mechanisms of action.