Expression of matrix metalloproteinase matrilysin (MMP-7) was induced by activated Ki-ras via AP-1 activation in SW1417 colon cancer cells

Inhibition of angiogenesis and metastasis in colorectal cancer cell lines through KRAS-associated signaling pathways by 2-methoxy-6-undecyl-1,4-benzoquinone

Colorectal cancer (CRC), the third most prevalent cancer globally, presents formidable hurdles in treatment owing to factors such as therapeutic resistance and genetic mutations affecting primary drug targets. 2-methoxy-6-undecyl-1,4-benzoquinone (BQ), derived from Ardisia crispa roots, has emerged as a potent anti-inflammatory and anti-angiogenic compound with substantial potential, as evidenced by previous studies. This study aimed to explore the potential of BQ in suppressing angiogenesis and metastasis in the human CRC cell lines LoVo and HCT116. Various in vitro and in silico studies have been conducted to elucidate the potential pathway(s) of BQ. BQ was highly cytotoxic, with an IC50 of 7.01 ± 0.6 μM in HCT116 and 9.58 ± 0.8 μM in LoVo cells. Moreover, BQ induced notable apoptotic activity and suppressed migration, invasion, and adhesion in both cell lines. The inhibition of MMP-2 suggests the potential of BQ to impede extracellular matrix degradation and CRC cell metastasis. BQ inhibits the expression of key proteins involved in angiogenesis and metastasis, including VEGF-A, VEGF-C, BRAF, ERK, KRAS, PI3K, and AKT. Molecular docking simulations illustrated the robust binding of BQ to CRC protein receptors. BQ holds promise in impeding CRC progression by targeting angiogenesis and metastasis, particularly through inhibition of the KRAS/BRAF/ERK and KRAS/PI3K/AKT signaling pathways.

Less aggressive treatment for less aggressive disease? A retrospective single-center study of pulmonary-limited metastases associated with colorectal cancer

OBJECTIVE

To explore the appropriate treatment strategies, clinical outcomes, and prognostic factors of patients with pulmonary-limited metastases derived from colorectal cancer (CRC), usually manifested as a less aggressive course.

METHODS

A retrospective review was conducted in 331 CRC patients diagnosed with pulmonary-limited metastases at a single institution between January 2011 and November 2017. The Kaplan-Meier method was used to calculate the overall survival (OS). Further analysis was conducted according to treatment modalities. Univariate and multivariate analyses were used to determine potential prognostic factors influencing OS.

RESULTS

With a median follow-up time of 38.6 months, the median OS in all patients was 45.2 months. A total of 163 patients received intensive local treatment with a median OS of 76.4 months, whereas 168 patients received palliative systemic treatment with a median OS of 29.7 months. The median OS was 68.9 months for patients treated with radiotherapy/radiofrequency ablation, with similar efficacy compared to surgery group, whose OS had not reached yet. No survival benefits were observed from the additional targeted therapy in systemic treatment group. The prognostic analysis demonstrated unilateral/bilateral lesions, synchronous/metachronous metastases, intensive local treatment, and resection of primary lesion that were significantly associated with survival of patients.

CONCLUSIONS

Intensive local treatment alone for pulmonary lesions was associated with excellent survival in certain patients with CRC presented with metastases confined to lungs. Doublet systemic chemotherapy as the first-line treatment also revealed satisfied efficacy and safety.

The current understanding on the impact of KRAS on colorectal cancer

KRAS (kirsten rat sarcoma viral oncogene) is a member of the RAS family. KRAS mutations are one of most dominant mutations in colorectal cancer (CRC). The impact of KRAS mutations on the prognosis and survival of CRC patients drives many research studies to explore potential therapeutics or target therapy for the KRAS mutant CRC. This review summarizes the current understanding of the pathological consequences of the KRAS mutations in the development of CRC; and the impact of the mutations on the response and the sensitivity to the current front-line chemotherapy. The current therapeutic strategies for treating KRAS mutant CRC, the difficulties and challenges will also be discussed.

Mast Cells, microRNAs and Others: The Role of Translational Research on Colorectal Cancer in the Forthcoming Era of Precision Medicine

Colorectal cancer (CRC) is a heterogeneous disease, molecularly and anatomically, that develops in a multi-step process requiring the accumulation of several genetic or epigenetic mutations that lead to the gradual transformation of normal mucosa into cancer. In fact, tumorigenesis is extremely complex, with many immunologic and non-immunologic factors present in the tumor microenvironment that can influence tumorigenesis. In the last few years, a role for mast cells (MCs), microRNAs (miRNAs), Kirsten rat sarcoma (KRAS) and v-raf murine sarcoma viral oncogene homologue B (BRAF) in cancer development and progression has been suggested, and numerous efforts have been made to thoroughly assess their correlation with CRC to improve patient survival and quality of life. The identification of easily measurable, non-invasive and cost-effective biomarkers, the so-called "ideal biomarkers", for CRC screening and treatment remains a high priority. The aim of this review is to discuss the emerging role of mast cells (MCs), microRNAs (miRNAs), KRAS and BRAF as diagnostic and prognostic biomarkers for CRC, evaluating their influence as potential therapy targets in the forthcoming era of precision medicine.

Peritoneum as the sole distant metastatic site of lung adenosquamous cell carcinoma: a case report

Background

Peritoneum metastasis of lung cancer is a rare event which, in addition to the peritoneum, usually involves multiple metastatic tissues. Here we report a case of a patient with lung adenosquamous cell carcinoma with the peritoneum as the sole distant metastatic site.

Case presentation

An 82-year-old Han Chinese man, in the teaching profession, was diagnosed with lung adenosquamous cell carcinoma in the upper lobe of his left lung with the involvement of ipsilateral hilar and mediastinal lymph nodes, and was initially staged as IIIa (cT₂N₂M₀). Molecular testing identified a mutation at KRAS G12A. Due to his poor physical condition, our patient was given gamma knife radiotherapy with a total dose of 28.0 Gy. Two weeks later, our patient was diagnosed as peritoneal metastasis identified by using magnetic resonance imaging and confirmed with ascitic cytology and peritoneal histology. No other distant metastatic sites such as liver, brain, bone, paranephroi, and lungs were found. Subsequently, our patient received palliative intraperitoneal chemotherapy, and died within 2 months.

Conclusions

Our patient represented a rare case of lung adenosquamous cell carcinoma harboring the KRAS G12A mutation, which metastasized distantly to the peritoneum only, and progressed rapidly.

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.

Association between KRAS mutation and lung metastasis in advanced colorectal cancer

Background:

KRAS mutations have been associated with lung metastases at diagnosis of metastatic colorectal cancer (mCRC), but the impact of this mutation on subsequent development of lung metastasis is unknown. We investigated KRAS mutation as a predictor of lung metastasis development.

Methods:

We retrospectively evaluated data from patients with mCRC whose tumour was tested for KRAS mutation from 2008 to 2010. The relationships of KRAS mutational status with time-to-lung metastasis (TTLM) and overall survival (OS) were analysed.

Results:

Of the 494 patients identified, 202 (41%) had tumours with KRAS mutation. KRAS mutations were associated with a shorter TTLM (median 15.2 vs 22.4 months; hazard ratio=1.40; P=0.002) and a two-fold greater odds of developing lung metastases during the disease course in patients with liver-limited mCRC at diagnosis (72 vs 56%, P=0.007). Overall survival did not differ by KRAS status.

Conclusions:

Lung metastasis was more likely to develop during the disease course in patients whose tumour had a KRAS mutation than in those whose tumour did not have a KRAS mutation. This finding may have an impact on decision making for surgical resection of metastatic disease.

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.

Dual inhibition of EGFR and c-Met kinase activation by MJ-56 reduces metastasis of HT29 human colorectal cancer cells

Quinazolinone derivatives are known to possess anticancer activities on cell metastasis and cell death in different human cancer cell lines. Here, we studied the anti-metastasis activity and the underlying mechanisms of the novel quinazoline derivative MJ-56 (6-pyrrolidinyl-2-(3-bromostyryl)quinazolin-4-one). MJ-56 inhibited cell migration and invasion of HT29 human colorectal cancer cells by wound-healing and Matrigel-coated transwell assays in a concentration-dependent manner. MJ-56-treated cells resulted in the reduced expression of matrix metalloproteinase (MMP)-2, -7, -9 and -10 and the reduced enzymatic activities of MMP-2 and MMP-9. In contrast, MJ-56-treated cells enhanced the expression of the tissue inhibitors of metalloproteinases (TIMPs) TIMP-1 and TIMP-2. Further analyses showed that MJ-56 attenuated the activities of epidermal growth factor receptor (EGFR), c-Met and the downstream ERK-mediated MAPK and PI3K/AKT/mTOR signaling pathways, which led to decreased protein synthesis by dephosphorylating the translation initiation factors eIF-4B, eIF-4E, eIF-4G and S6 ribosomal protein. In addition, MJ-56 interfered with the NF-κB signaling via impairing PI3K/AKT activation and subsequently reduced the NF-κB-mediated transcription of MMPs. Taken together, the reduced expression of phosphor-EGFR and c-MET is chiefly responsible for all events of blocking metastasis. Our results suggest a potential role of MJ-56 on therapy of colorectal cancer metastasis.

KRAS status and clinical outcome in metastatic colorectal cancer patients treated with first-line FOLFOX chemotherapy

BACKGROUND

Two previous first-line studies showed an improved trend in response rate (RR) and progression free survival (PFS) in metastatic colorectal cancer (CRC) patients with KRAS mutation. Others have reported a worsened outlook for metastatic CRC patients with KRAS mutation and a higher likelihood of metastatic disease to the lungs. In this study, we aimed to address the impact of KRAS on the pattern of metastatic disease at presentation and on RR and PFS with first-line 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) chemotherapy.

METHODS

Patients with CRC who underwent KRAS testing using DxS assay at Roswell Park Cancer Institute (RPCI) were identified. Patients with metastatic CRC treated with first-line FOLFOX +/- bevacizumab were assessed for response and survival using RECIST 1.1 guidelines. A two-sided Fisher's exact test was used to determine the statistical significance.

RESULTS

181 patients with metastatic CRC and KRAS testing were identified. 83/181 patients were treated with FOLFOX (+/- bevacizumab) in the first-line setting at RPCI and were evaluable as per study guidelines. KRAS mutation (MT) occurred in 40.31% cases. There was no difference in organ-metastases distribution, RR (56.60% in KRAS wild-type (WT) and 50% in KRAS mutant) or PFS (9.3 months KRAS WT and 8.7 months in KRAS MT) based on KRAS status.

CONCLUSION

In this single institute study, our findings do not support any predictive role for KRAS-MT in terms of response to FOLFOX first-line chemotherapy, or in terms of sites of metastatic disease at mCRC presentation.

Mesothelin enhances invasion of ovarian cancer by inducing MMP-7 through MAPK/ERK and JNK pathways

Ovarian cancer has one of the highest mortalities in malignancies in women, but little is known of its tumour progression properties and there is still no effective molecule that can monitor its growth or therapeutic responses. MSLN (mesothelin), a secreted protein that is overexpressed in ovarian cancer tissues with a poor clinical outcome, has been previously identified to activate PI3K (phosphoinositide 3-kinase)/Akt signalling and inhibit paclitaxel-induced apoptosis. The present study investigates the correlation between MSLN and MMP (matrix metalloproteinase)-7 in the progression of ovarian cancer, and the mechanism of MSLN in enhancing ovarian cancer invasion. The expression of MSLN correlated well with MMP-7 expression in human ovarian cancer tissues. Overexpressing MSLN or ovarian cancer cells treated with MSLN showed enhanced migration and invasion of cancer cells through the induction of MMP-7. MSLN regulated the expression of MMP-7 through the ERK (extracellular-signal-regulated kinase) 1/2, Akt and JNK (c-Jun N-terminal kinase) pathways. The expression of MMP-7 and the migrating ability of MSLN-treated ovarian cancer cells were suppressed by ERK1/2- or JNK-specific inhibitors, or a decoy AP-1 (activator protein 1) oligonucleotide in in vitro experiments, whereas in vivo animal experiments also demonstrated that mice treated with MAPK (mitogen-activated protein kinase)/ERK- or JNK-specific inhibitors could decrease intratumour MMP-7 expression, delay tumour growth and extend the survival of the mice. In conclusion, MSLN enhances ovarian cancer invasion by MMP-7 expression through the MAPK/ERK and JNK signal transduction pathways. Blocking the MSLN-related pathway could be a potential strategy for inhibiting the growth of ovarian cancer.

K-ras mutations are correlated to lymph node metastasis and tumor stage, but not to the growth pattern of colon carcinoma

In colorectal carcinoma, pathological assessment of tumors is essential for determining therapy and prognosis of the disease. Molecular associations of tumor complexity index and genetic alternations can be helpful to understand the tumor progression mechanism. Oncogenic K-ras is one of the major colorectal cancer associated genes, and is mutated in up to 50% of colorectal cancers. In this current study, we correlated tumor complexity index with mutations in K-ras codon 12, 13, and 61 in association with different clinicopathological parameters such as TNM stage, localization, sex, and age. Formalin-fixed paraffin embedded tissue blocks from colon cancer samples was selected from 88 patients diagnosed with adenocarcinoma. Mutations in the K-ras gene were detected using pyrosequencing technique. Tumor complexity index was calculated using immunohistochemically stained images of the tumor outline of the specimens and then analyzing these pictures using Photoshop CS, Fovea Pro, and Image J computer programs. Statistical analysis was performed with SPSS. K-ras mutations were detected in 17 (19.3%) colon cancer samples. Most of the samples were at a lower complexity index. No correlation was observed between K-ras mutations and complexity index. However, K-ras mutations were correlated with regional lymph node metastasis and tumor stages and complexity index with tumor wall penetration. In conclusion, complexity index and K-ras mutations are independent events; however, both correlate with tumor progression and are important in the biologic development of colon carcinoma.

Upregulation of equine matrix metalloproteinase 1 by bovine papillomavirus type 1 is through the transcription factor activator protein-1

Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by extensive invasion and infiltration of lymphatics, rare regression and high recurrence after surgical intervention. Bovine papillomavirus type 1 (BPV-1) activity is necessary for the transformation phenotype of equine fibroblasts. Among the many changes induced by BPV-1, matrix metalloproteinase 1 (MMP-1) upregulation contributes to the invasiveness of equine fibroblasts. However, it is not yet known how BPV-1 proteins regulate equine MMP-1 expression. To elucidate this mechanism, the equine MMP-1 promoter was cloned and analysed. A putative activator protein-1 (AP-1)-binding site was demonstrated to be crucial for upregulated MMP-1 promoter activity by BPV-1. BPV-1 E6 and E7 proteins increased MMP-1 promoter activity, and inhibition of BPV-1 gene expression by small interfering RNA significantly reduced the promoter activity. c-Jun and Fra-1, two components of the AP-1 transcription factor complex, were overexpressed and activated by BPV-1 in equine fibroblasts. Finally, BPV-1 E5, E6 and E7 proteins increased MMP-1 mRNA and protein expression. In conclusion, the expression of MMP-1 can be enhanced by BPV-1 oncoproteins E6 and E7 through the AP-1 transcription factor and by E5 via an indirect mechanism. These findings shed light on the mechanism of BPV-1-mediated equine fibroblast infiltration and indicate that both BPV-1 oncoproteins and AP-1 could be potential targets for equine sarcoid therapy.

Liver membrane proteome glycosylation changes in mice bearing an extra-hepatic tumor

Cancer is well known to be associated with alterations in membrane protein glycosylation (Bird, N. C., Mangnall, D., and Majeed, A. W. (2006) Biology of colorectal liver metastases: A review. J. Surg. Oncol. 94, 68-80; Dimitroff, C. J., Pera, P., Dall'Olio, F., Matta, K. L., Chandrasekaran, E. V., Lau, J. T., and Bernacki, R. J. (1999) Cell surface n-acetylneuraminic acid alpha2,3-galactoside-dependent intercellular adhesion of human colon cancer cells. Biochem. Biophys. Res. Commun. 256, 631-636; and Arcinas, A., Yen, T. Y., Kebebew, E., and Macher, B. A. (2009) Cell surface and secreted protein profiles of human thyroid cancer cell lines reveal distinct glycoprotein patterns. J. Proteome Res. 8, 3958-3968). Equally, it has been well established that tumor-associated inflammation through the release of pro-inflammatory cytokines is a common cause of reduced hepatic drug metabolism and increased toxicity in advanced cancer patients being treated with cytotoxic chemotherapies. However, little is known about the impact of bearing a tumor (and downstream effects like inflammation) on liver membrane protein glycosylation. In this study, proteomic and glycomic analyses were used in combination to determine whether liver membrane protein glycosylation was affected in mice bearing the Engelbreth-Holm Swarm sarcoma. Peptide IPG-IEF and label-free quantitation determined that many enzymes involved in the protein glycosylation pathway specifically; mannosidases (Man1a-I, Man1b-I and Man2a-I), mannoside N-acetylglucosaminyltransferases (Mgat-I and Mgat-II), galactosyltransferases (B3GalT-VII, B4GalT-I, B4GalT-III, C1GalT-I, C1GalT-II, and GalNT-I), and sialyltransferases (ST3Gal-I, ST6Gal-I, and ST6GalNAc-VI) were up-regulated in all livers of tumor-bearing mice (n = 3) compared with nontumor bearing controls (n = 3). In addition, many cell surface lectins: Sialoadhesin-1 (Siglec-1), C-type lectin family 4f (Kupffer cell receptor), and Galactose-binding lectin 9 (Galectin-9) were determined to be up-regulated in the liver of tumor-bearing compared with control mice. Global glycan analysis identified seven N-glycans and two O-glycans that had changed on the liver membrane proteins derived from tumor-bearing mice. Interestingly, α (2,3) sialic acid was found to be up-regulated on the liver membrane of tumor-bearing mice, which reflected the increased expression of its associated sialyltransferase and lectin receptor (siglec-1). The overall increased sialylation on the liver membrane of Engelbreth-Holm Swarm bearing mice correlates with the increased expression of their associated glycosyltransferases and suggests that glycosylation of proteins in the liver plays a role in tumor-induced liver inflammation.

Assessment of K-ras mutation: a step toward personalized medicine for patients with colorectal cancer

Some of the most significant therapeutic advances in the treatment of cancer have occurred in the management of colorectal metastases. The introduction of new cytotoxic chemotherapeutic and biologic agents has changed the approach to these patients from both an oncologic and a surgical perspective. In addition, an understanding of the molecular mechanisms by which these agents affect tumors is developing. This molecular information will be critical in the future in designing therapeutic regimens based on an individual tumor's genetic profile rather than treatment for a specific tumor type. The rapidly evolving treatment of colon cancer has provided several interesting genetic biomarkers/pathways/genes-/kinases that have been targeted or seem to play an important role. Of particular interest is the blockade of epidermal growth factor receptor (EGFR) with monoclonal antibodies. This treatment is efficacious when used alone or combined with chemotherapy. However, recent data revealed that patients with tumors positive for the K-ras mutation do not benefit from EGFR blockade. Compelling evidence has indicated that mutated K-ras is an important oncogene involved at the early stage of the development of colorectal cancer. Furthermore, mutations in the K-ras gene have been associated with aggressive tumor biology. K-ras mutational analysis is an important step in the overarching goal of developing personalized medicine. New treatment strategies are needed to more effectively treat patients with the K-ras mutation.

Andrographolide could inhibit human colorectal carcinoma Lovo cells migration and invasion via down-regulation of MMP-7 expression

Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, is known to possess multiple pharmacological activities. In our previous study, Andro had been shown to have potent anti-cancer activity against human colorectal carcinoma Lovo cells by inhibiting cell-cycle progression. To further investigate the mechanism for the anti-cancer properties of Andro, it was used to examine the effect on migration and invasion of Lovo cells. The results of wound-healing assay and in vitro transwell assay revealed that Andro inhibited dose-dependently the migration and invasion of Lovo cells under non-cytotoxic concentrations. Using zymographic assay and RT-PCR, the results revealed that Andro diminished the activity and the mRNA and protein levels of MMP-7, but not MMP-2 or MMP-9. The down-regulation of MMP-7 appeared to be via the inactivation of activator protein-1 (AP-1) since the treatment with Andro suppressed the nuclear protein level of AP-1, which was accompanied by a decrease in DNA-binding level of the factor. Taken together, these results indicated that Andro reduces the MMP-7-mediated cellular events in Lovo cells, and provided a new mechanism for its anti-cancer activity.

Serum matrilysin levels predict outcome in curatively resected colorectal cancer patients

BACKGROUND

Matrix metalloproteinase 7 (MMP-7) is involved in invasion, metastasis, growth, and angiogenesis. The aim of this study is to assess the prognostic role of serum MMP-7 in curatively resected colorectal cancer (CRC).

MATERIALS AND METHODS

Patients undergoing resection for CRC (n = 175) were recruited from July 2003 to December 2004. MMP-7 was determined using a quantitative solid phase sandwich ELISA. Cox analysis was used to assess the role of MMP-7 in predicting overall survival (OS) and disease-free survival (DFS).

RESULTS

The median length of follow-up was 45 months (range 1 to 59). Levels of MMP-7 are predictors of DFS (hazard ratio [HR] 1.119, 95% confidence interval [95% CI] 1.038-1.207) and of OS (HR 1.113, 95% CI 1.025-1.209). Patients with MMP-7 higher than the median (4.3 ng/ml) are more likely to relapse (29.5% vs 18.4%, P = .084); median time to progression in relapsed patients is 8 months if MMP-7 is > or =4.3 ng/ml and 18 months if MMP-7 is <4.3 ng/ml. Node-negative patients with low MMP-7 have a predicted probability of relapse-free survival at 4 years of 88% (95% CI 83-92%); if the MMP-7 is higher than the median value; this probability is 77% (95% CI 73-81%).

CONCLUSION

MMP-7 predicts recurrence in curatively resected CRC patients.

Serum matrix metalloproteinase 7 levels identifies poor prognosis advanced colorectal cancer patients

Metalloproteinase 7 (MMP-7) plays an important role in tumor growth, invasion and dissemination, and is secreted to the media. Because of the close implication of MMP-7 in cancer biology, we sought to define the prognostic significance of serum levels of MMP-7 in metastatic colorectal cancer (CRC) and explore its possible impact in the daily clinical practice. MMP-7 expression was determined by enzyme-linked immunoabsorbent assay. We assessed serum MMP-7 levels in 87 healthy controls, 96 patients with nonmetastatic CRC and 120 patients with advanced CRC. Clinical information was gathered from patient files. Cox proportional hazards model was used to assess survival. MMP-7 and the variables associated with prognosis were entered and a backward elimination method was employed to adjust the model. Inclusion criteria was p </= 0.05 and exclusion criteria was p >/= 0.10. Advanced CRC patients have a significant higher mean serum MMP-7 levels (13.4 ng/ml) than those in nonmetastatic CRC (5.5 ng/ml; p < 0.001) and healthy controls (4.2 ng/ml; p < 0.001). In metastatic patients, after adjusting for other prognostic variables, MMP-7 (entered as a continuous variable) is associated with decreased survival (HR 1.016, IC 95% 1.002-1.031). Serum MMP-7 levels are significantly elevated in patients with advanced CRC. In conclusion, MMP-7 is an independent prognostic factor for survival in advanced CRC. In our sample, the risk of death associated to MMP-7 increase is much higher than the risk of death associated to lactate dehydrogenase elevation.

KRAS and BRAF oncogenic mutations in MSS colorectal carcinoma progression

In sporadic colorectal cancer (CRC), KRAS are alternative to BRAF mutations and occur, respectively, in 30 and 10% of cases. Few reports addressed the association between KRAS-BRAF mutations and tumour progression specifically in sporadic microsatellite-stable (MSS) CRC. We screened KRAS and BRAF in 250 MSS primary CRC and 45 lymph node (LN) metastases and analysed the pathological features of the cases to understand the involvement of KRAS-BRAF activation in progression and metastasis. Forty-five per cent of primary MSS CRCs carried mutations in at least one of these genes and mutations were associated with wall invasion (P=0.02), presence and number of LN metastases (P=0.02 and P=0.03, respectively), distant metastases (P=0.004) and advanced stage (P=0.01). We demonstrated that KRAS and BRAF are alternative events in Tis and T1 MSS CRC and, KRAS rather than BRAF mutations, contributed to the progression of MSS CRC. The frequency of KRAS and/or BRAF mutations was higher in LN metastases than in primary carcinomas (P=0.0002). Mutated LN metastases displayed KRAS associated or not with BRAF mutations. BRAF mutations were never present as a single event. Concomitant KRAS and BRAF mutations increased along progression of MSS CRCs, suggesting that activation of both genes is likely to harbour a synergistic effect.

Exposure to a metabolite of the environmental toxicant, trichloroethylene, attenuates CD4+ T cell activation-induced cell death by metalloproteinase-dependent FasL shedding

Long-term exposure to the environmental contaminant trichloroethylene (TCE) in drinking water has been shown to promote autoimmune disease in association with the expansion of activated CD4+ T cells. The effects of TCE on CD4+ T cells were linked in the present study to the ability of TCE metabolite, trichloroacetaldehyde hydrate (TCAH), to inhibit activation-induced cell death (AICD) in CD4+ T cells. TCAH attenuated AICD in CD4+ T cells by decreasing FasL (CD178) expression but not by altering Fas (CD95) expression or by interfering with Fas-signaling events following direct engagement of the Fas receptor. The TCAH-induced decrease in FasL expression did not appear to be mediated at the transcriptional level but was instead due to increased shedding of FasL from the surface of the CD4+ T cells. The ability of TCAH to cleave FasL and thereby decrease AICD appeared to be mediated by metalloproteinases and correlated with a TCAH-induced increase in matrix metalloproteinase-7. Thus, this study presents the novel finding that the environmental contaminant TCE works via its metabolite TCAH to attenuate AICD by increasing metalloproteinase activity that cleaves FasL from CD4+ T cells. This represents a mechanism by which an environmental trigger inhibits AICD in CD4+ T cells and may thereby promote CD4+ T cell-mediated autoimmune disease.

AP-1 and colorectal cancer

Activator protein-1 (AP-1) is a transcription factor that consists of either a Jun-Jun homodimer or a Jun-Fos heterodimer. AP-1 regulates the expression of multiple genes essential for cell proliferation, differentiation and apoptosis. Numerous reports suggest that AP-1 plays an important role in various human diseases. Among them, the roles relating to human cancers have been strongly suggested for a long time. In human cancers, colorectal cancer is still a leading cause of morbidity and mortality in the world. Since there are some reports about the role of AP-1 in colorectal cancer response to a number of stimuli, such as cytokines and growth factors, and oncogenictransformation, therapeutic inhibition of AP-1 activity has attracted considerable interest. Here, we demonstrate the biological properties of AP-1 and its role in colorectal cancer, and discuss a possibility of an AP-1 inhibitor, an adenovirus dominant-negative mutant of c-Jun, as a therapeutic agent for gene therapy.

Control of colorectal metastasis formation by K-Ras

Mutational activation of the K-Ras proto-oncogene is frequently observed during the very early stages of colorectal cancer (CRC) development. The mutant alleles are preserved during the progression from pre-malignant lesions to invasive carcinomas and distant metastases. Activated K-Ras may therefore not only promote tumor initiation, but also tumor progression and metastasis formation. Metastasis formation is a very complex and inefficient process: Tumor cells have to disseminate from the primary tumor, invade the local stroma to gain access to the vasculature (intravasation), survive in the hostile environment of the circulation and the distant microvascular beds, gain access to the distant parenchyma (extravasation) and survive and grow out in this new environment. In this review, we discuss the potential influence of mutant K-Ras on each of these phases. Furthermore, we have evaluated the clinical evidence that suggests a role for K-Ras in the formation of colorectal metastases.

(-)-Epigallocatechin-3-gallate promotes pro-matrix metalloproteinase-7 production via activation of the JNK1/2 pathway in HT-29 human colorectal cancer cells

Matrix metalloproteinase (MMP)-7 (matrilysin-1) plays significant roles in the growth, invasion, and metastasis of colorectal tumors, while (-)-epigallocatechin-3-gallate (EGCG), a green tea polyphenol with chemopreventive properties, has been shown to be an inhibitor of MMP-2 and MMP-9. In the present study, HT-29 human colorectal cancer cells were treated with EGCG to examine its effects on pro-MMP-7 induction and production using RT-PCR and western blot analyses. Surprisingly, EGCG (10-100 microM) treatment increased both intracellular and extracellular pro-MMP-7 protein levels (2.6-8.4-fold and 1.9-6.4-fold, respectively) in dose- and time-dependent manner, with a significant upregulation of its mRNA expression. EGCG also activated extracellular signal-regulated protein kinase (ERK)1/2, c-JUN NH2-terminal kinase (JNK)1/2 and p38 mitogen-activated protein kinase (MAPK), as previously reported. In addition, the polyphenol triggered the phosphorylation of c-JUN (Ser63 and Ser73) and induced c-JUN/c-FOS, thereby increasing the DNA binding activity of activator protein-1 (AP-1), as shown by an AP-1 luciferase reporter assay. Pharmacological blockade of MAPK activities suggested that pro-MMP-7 expression was induced via JNK1/2 activation, but not in the case of ERK1/2 or p38 MAPK. N-Acetyl-L-cysteine, superoxide (O2-) dismutase and catalase attenuated the EGCG-induced pro-MMP-7 production, suggesting an involvement of oxidative stress in these events. Conversely, EGCG spontaneously generated O2- in a cell-free system that utilized a cytochrome C reduction method. Further, (-)-epicatechin-3-gallate (25 and 100 microM) and green tea polyphenols (33 and 132 microg/ml) induced pro-MMP-7 expression, whereas (-)-epicatechin and (-)-epigallocatechin (100 microM each) did not. Induction of pro-MMP-7 expression by EGCG was also shown in another human colorectal adenocarcinoma cell line, Caco-2. Our results suggest that some green tea catechins induce pro-MMP-7 production via O2- production and the activation of JNK1/2, c-JUN, c-FOS and AP-1 in HT-29 cells.

K-ras mutation influences macroscopic features of gastric carcinoma

INTRODUCTION

Gastric carcinoma is classified morphologically as type 1 to 4. Type 1 is defined as a polypoid tumor; types 2 and 3 are defined as ulcerated tumors with polypoid growth or gastric wall infiltration, respectively, and type 4 tumors are defined as flat. This morphological classification is important because biological characteristics differ between the four morphological types, but little is known about genetic differences between them.

MATERIALS AND METHODS

One hundred eight gastric tumors were classified macroscopically as type 1 to 4. Tumoral DNA was microdissected from paraffin-embedded tissue sections. PCR amplification of exon 1 of a K-ras containing codons 12 and 13 was performed. K-ras amplicons were dot-blotted onto nylon filters and hybridized with radiolabeled oligomer primers.

RESULTS

A K-ras mutation was found in 20 of 108 gastric cancers. A significant relationship of K-ras mutation with polypoid cancer was found. The frequency of K-ras mutation was 6/14 (43%), 8/29 (28%), 2/11 (18%), and 4/54 (7%) in type 1 to 4 tumors, respectively. K-ras mutation was correlated with well-differentiated tumors. Of various types of K-ras mutations, 12 Asp often was seen in type 1 and 2 gastric cancers (well-demarcated, elevated tumors), while 12 Val and 12 Ser were often seen in type 3 and 4 cases (infiltrating carcinomas).

CONCLUSION

K-ras mutations occur prominently in type 1 and type 2 gastric cancers.

Synergistic cooperation between the AP-1 and LEF-1 transcription factors in activation of the matrilysin promoter by the src oncogene: implications in cellular invasion

The matrix metalloprotease matrilysin is expressed in premalignant polyps and plays a key role in local invasion during the progression of digestive tumors. In the present work, we investigated the possible relationships between the activity of the mouse and human matrilysin promoters (Mp), endogenous matrilysin protein expression, and two early oncogenetic defects frequently observed in human colonic cancers, namely activation of the src oncogene and impairment of the Wnt/APC/beta-catenin pathway. Using transient transfection assays, we report here that src signaling and the HMG-box transcription factor LEF-1 act synergistically with the proximal (-61 to -67) AP-1 binding site to transactivate the Mp in premalignant and tumorigenic kidney and colonic epithelial cells, through beta-catenin- and axin-independent signaling pathways. This synergism involves the -109 and -194 Tcf/LEF-1 binding sites in the Mp and a physical interaction between LEF-1 and c-Jun. Furthermore, src coordinates accumulation of the c-Jun factor and matrilysin transcripts. Conversely, the c-Jun dominant negative mutant TAM67 and the src tyrosine kinase inhibitor M475271 impaired src-induced Mp activation, matrilysin protein accumulation, and invasion of type I collagen gels. This mechanism may thereby contribute to cellular invasion during the early-stage adenoma/adenocarcinoma conversion and the metastatic process of digestive tumors.

Expression profiling of CC531 colon carcinoma cells reveals similar regulation of beta-catenin target genes by both butyrate and aspirin

The CC531 cell line has been widely used to study different aspects of tumor growth and metastasis and provides an excellent experimental platform to develop novel antitumor strategies. To characterize the CC531 model at the molecular level, we screened for mutations in genes covering important signal-transduction pathways that are known to play major roles during colon carcinogenesis, the wnt and the ki-ras signaling pathways. We found both a prototypic beta-catenin (Ctnnb1) mutation (Thr(41)Ile) and a ki-ras (G12D) mutation, providing unambiguous evidence for the constitutive activation of these pathways in CC531 cells. We further established comprehensive gene expression profiles of CC531 cells and investigated the molecular response to 2 antitumor drugs, butyrate and aspirin. Using oligonucleotide microarrays, we screened the expression levels of 7,700 genes and identified a total of 398 genes whose expression was significantly changed upon treatment with butyrate. When using aspirin, 121 genes were significantly altered. Interestingly, 36 genes were regulated by both butyrate and aspirin and 35 of them were regulated in the same direction. We found 7 differentially expressed genes, cyclin D1, cyclin E, c-myc, Fosl1, c-fos, Cd44 and follistatin, which are known targets of the beta-catenin and/or the ras pathway. In all cases, butyrate and aspirin reversed the changes in expression normally found in response to active signaling of these oncogenic pathways. The microarray data are available (http://ncbi.nlm.nih.gov/geo/).

Antisense oligonucleotides specific to mutated K-ras genes inhibit invasiveness of human pancreatic cancer cell lines

BACKGROUND/AIMS

Point mutations of the K-ras gene are detected in > 90% of human pancreatic cancers and may play an important role in tumorigenesis. However, correlations between mutant K-ras and the invasive activity of the tumor have remained unclarified.

METHODS

17-merphosphorothioate antisense oligonucleotides targeting K-ras point mutations were transfected into three kinds of human pancreatic cancer cell lines (MIAPaCa-2, PANC-1, and BxPC-3), and the invasive activity was investigated using an in vitro chemoinvasion assay.

RESULTS

Antisense oligonucleotides strongly inhibited the invasive activity of the cell lines with mutant K-ras genes (MIAPaCa-2, PANC-1), but not in that with a wild-type K-ras (BxPC-3).

CONCLUSION

Antisense oligonucleotides specific to mutated K-ras genes inhibited the invasiveness of human pancreatic cancer cell lines. Specific antisense therapy to the point mutation of K-ras might be a new anticancer strategy for pancreatic cancer.

Change in gene expression subsequent to induction of Pnn/DRS/memA: increase in p21(cip1/waf1)

Pnn (PNN) is a nuclear and cell adhesion-related protein. Previous work has suggested that Pnn/DRS/memA is a potential tumor suppressor involved in the regulation of cell adhesion and cell migration. Using the ecdysone-inducible mammalian expression system, a stable inducible GFP-tagged human Pnn gene (PNNGFP) expressing 293 cell line was created (EcR293-PNNGFP). Cells induced to express PNNGFP not only exhibited increased cell-cell adhesion but also exhibited changes in cell growth and cell cycle progression. cDNA array analyses, together with real time PCR, revealed that the effects of exogenously expressed Pnn on cellular behavior may be linked to the regulation of the expression of specific subset genes. This subset includes cell cycle-related genes such as p21(cip1/waf1), CDK4, CPR2; cell migration and invasion regulatory genes such as RhoA, CDK5, TIMP-1, MMP-7, and EMMPRIN; and MIC-1. Concordant with previous observations of Pnn-induced phenotype changes, genes coding for epithelial associated processes and cell division controls were elevated, while those coding for increased cell motility and cellular reorganizations were downregulated. We utilized p21 promoter-luciferase reporter constructs and demonstrated that a marked stimulation of p21 promoter activity in 293 cells correlated with increased Pnn expression. Taken together, these data indicate that Pnn may participate in the regulation of gene expression, thereby, positively promoting cell-cell adhesion, and negatively affecting cell migration and cell proliferation.

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.

The dominant negative H-ras mutant, N116Y, suppresses growth of metastatic human pancreatic cancer cells in the liver of nude mice

In pancreatic cancer, the mutation of c-K-ras is a critical event of tumor growth and metastasis. We have previously demonstrated a dominant negative effect of N116Y on the growth of pancreatic cancer cells. To evaluate the potential of N116Y for suppressing the metastatic growth of pancreatic tumor cells, we made a replication-deficient recombinant N116Y adenovirus driven by the carcinoembryonic antigen (CEA) promoter (Ad CEA-N116Y). We demonstrated that the expression of N116Y, growth inhibition, and apoptotic death induction were all specific to pancreatic cancer cell lines (PCI-35 and PCI-43) that were promoter positive, whereas no growth retardation was observed in human embryonic pancreas-derived cell line 1C3D3 after Ad CEA-N116Y infection. We examined the effect of Ad CEA-N116Y on the metastatic growth of PCI-43 colonies in liver, which was generated by tumor injection into the spleen of nude mice. The results showed that Ad CEA-N116Y effectively reduced the number of metastatic colonies without any complication by injecting intrasplenically 5 days after tumor cell inoculation. Thus, N116Y can selectively suppress the metastatic growth of pancreatic tumor cell by using the CEA promoter-driven adenovirus vector indicating that N116Y gene therapy may be potentially useful for the treatment of pancreatic cancer patients with liver micrometastasis.

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.

EGF induces the expression of matrilysin in the human prostate adenocarcinoma cell line, LNCaP

BACKGROUND

Matrix metalloproteinases (MMPs) are regulated both positively and negatively at the transcriptional level by a variety of growth factors, oncogenes, and tumor promoters. Induction of the MMP, matrilysin, by epidermal growth factor (EGF) was investigated in a human prostate cancer cell line.

METHODS

Secreted protein and messenger RNA were detected using Western and Northern methods, respectively. EGF receptor antibodies were used for neutralization of the EGF receptor to determine the role of the EGF growth factor family (EGF, transforming growth factor alpha (TGFalpha), or amphiregulin) in the basal induction of matrilysin.

RESULTS

EGF increased mRNA and secreted protein levels for the MMP matrilysin in LNCaP cells, in a concentration- and time-dependent manner. Transforming growth factor beta1 (TGFbeta1) had no inhibitory effect on the levels of mRNA or secreted protein induced by EGF in LNCaP cells. Decay of matrilysin mRNA after the addition of actinomycin D indicated that the half-life of matrilysin mRNA was not altered by EGF. Blocking with a neutralizing antibody to the EGF receptor did not alter the basal level of secreted matrilysin.

CONCLUSIONS

Exogenously added EGF increased matrilysin mRNA, perhaps at a transcriptional level. Growth factors, other than the members of the EGF family which act through the EGF receptor, may be involved in the regulation of the basal level of secreted matrilysin in LNCaP cells. Our data with LNCaP cells suggest that paracrine regulation of matrilysin expression in human prostate carcinoma cells could be via the EGF receptor.

Structural differences between valine-12 and aspartate-12 Ras proteins may modify carcinoma aggression

Recent evidence associates the codon 12 valine-for-glycine (G12V) mutant Ki-Ras protein with higher stage and increased lethality of colorectal carcinomas, while the codon 12 aspartate-for-glycine (G12D) Ras mutation shows no such association. Several observations may be relevant to this phenomenon. First, GTPase activity of G12V Ras is one-quarter that of G12D Ras and one-tenth that of wild-type (WT) Ras. Second, binding of the GTP analogue GppNp to G12D Ras is 8-fold weaker than its binding to G12V or WT Ras and crystal structures indicate that electrostatic repulsion between the carboxylate group of the G12D Asp-12 side-chain and the gamma phosphate of the bound nucleotide may make GTP binding to G12D Ras weaker even than that of GppNp. It is proposed that this lowering of affinity for GTP allows G12D Ras an escape from the oncogenic GTP-bound state, whereas GTP tightly bound to G12V mutant Ras generates a more persistent, potentially oncogenic, signal. Structural comparisons also suggest that differences between the Switch I (effector) region of G12D and G12V Ras could modify interactions with downstream signalling molecules such as Raf-1, neurofibromin, and phosphatidylinositol 3-hydroxy-kinase. Other differences between the G12D and G12V mutant Ras proteins include a lower affinity of the GTPase activating protein GAP for G12V than for G12D or WT Ras; but, as both G12D and G12V Ras are refractory to GTPase activation by GAP binding, this may be less significant. These studies complement experimental data showing that such Ras mutations differ in their effects in vitro and in vivo and, with recent data indicating heterogeneity of ras mutation in colorectal carcinomas and other tumours, make it plausible that codon 12 Ras mutations differ in carcinogenic potential and prognostic significance.

Role of mitogen-activated protein kinases and c-Jun/AP-1 trans-activating activity in the regulation of protease mRNAs and the malignant phenotype in NIH 3T3 fibroblasts

Ras activates a multitude of downstream activities with roles in cellular proliferation, invasion and metastasis, differentiation, and programmed cell death. In this work we have evaluated the requirement of extracellular signal-regulated protein kinase (ERK), c-Jun NH2-terminal kinase kinase (JNKK), and c-Jun/AP-1 activities in transformation and extracellular matrix invasion of ras oncogene expressing NIH 3T3 fibroblasts by expressing stable mutant genes that constitutively inhibit these activities. Whereas the inhibition of ERK activity reverts the transformed and invasive phenotype, the inhibition of the JNK pathway and AP-1 trans-activating activities by JNKK[K129R] and c-Jun(TAM67) had no effect on the ability of the ras oncogene-expressing cells to grow in soft agar or invade Matrigel basement membrane. Thus an elevated JNK activity and/or c-Jun/AP-1 trans-activating activity are not absolute requirements for ras transformation or invasion through basement membrane, and the dependence on AP-1 activity for transformation is cell-specific. However, inhibition of JNK kinase (JNKK) in ras-transformed cells with normally elevated JNK activity switches the protease-dependent invasive phenotype from a urokinase plasminogen activator (uPA)-dependent to a cathepsin L (CL)-dependent invasive phenotype. Conversely, treatment of ras-transformed cells of low constitutive JNK activity with the JNK stimulator, anisomycin, converts the protease mRNA levels from those characteristic of a CL-dependent to a uPA-dependent phenotype. These protease phenotypes can be duplicated in untransformed NIH 3T3 cells that express platelet-derived growth factor receptors and m1 muscarinic receptors that selectively stimulate the ERK or JNK pathways, respectively. It is concluded that high ERK activity is required for both protease phenotypes, whereas the JNK pathway and c-Jun/AP-1 activity are not required for transformation but regulate a switch between uPA and CL protease phenotypes in both transformed and untransformed cells. In ras-transformed NIH 3T3 fibroblasts, the uPA- and CL-dependent protease phenotypes are redundant in their ability to invade through basement membrane.

Heterogeneity of mutant versus wild-type Ki-ras in primary and metastatic colorectal carcinomas, and association of codon-12 valine with early mortality

The point mutations occurring in codons 12 and 13 of Ki-ras in 78 patients with colorectal carcinoma (31 Dukes' A and B, 21 Dukes' C, and 26 Dukes' D) have been determined by allele-specific oligonucleotide hybridization and sequencing. Duplicate samples of invasive primary carcinoma, adjacent normal tissue, and available lymph node and liver metastases from the same patients were microdissected from paraffin sections. There were no differences in the mutation rate between primary carcinomas and secondary deposits: 26 of 78 (33 per cent) primary carcinomas, 10 of 32 (31 per cent) lymph node metastases, and 10 of 26 (38 per cent) liver metastases. Multiple sampling revealed frequent heterogeneity within carcinomas: 9 of 26 primaries with Ki-ras mutations also contained areas of carcinoma with only the wild-type gene, implying that Ki-ras mutation, even when present in a colonic carcinoma, may not have been necessary for establishing the malignant phenotype. Also, 2 of 26 (8 per cent) Dukes' D patients had a mutation in their primary carcinoma but none in liver metastases and 6 of 47 (13 per cent) Dukes' C and D patients had mutations in liver or lymph node metastases but none in the primary carcinoma. Such heterogeneity may modify the effectiveness of novel therapies targeting mutant Ki-ras function, such as farnesyltransferase inhibition. Mutation of codon 12 from GGT (glycine) to GTT (valine) was more prevalent in primary and metastatic deposits of Dukes' C/D carcinomas (P = 0.01) than in primary carcinomas from Dukes' A/B patients. Mutations of codon 12 to GAT, AGT, GCT and codon 13 GGC to GAC were also found, but no correlation with carcinoma aggressiveness was apparent. Follow-up of 71/78 patients (up to 12 years) revealed decreased overall survival (P = 0.001) in patients with the GGT to GTT transversion in codon 12, even when the analysis was restricted to Dukes' D cases, supporting the suggestion that this mutation may confer a more aggressive phenotype in colorectal carcinoma.

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.