Invasion and metastasis markers in cancers

Development and validation of a novel survival model for head and neck squamous cell carcinoma based on autophagy-related genes

BACKGROUND

In view of the critical role of autophagy-related genes (ARGs) in the pathogenesis of various diseases including cancer, this study aims to identify and evaluate the potential value of ARGs in head and neck squamous cell carcinoma (HNSCC).

METHODS

RNA sequencing and clinical data in The Cancer Genome Atlas (TCGA) were analyzed by univariate Cox regression analysis and Lasso Cox regression analysis model established a novel 13- autophagy related prognostic genes, which were used to build a prognostic risk model. A multivariate Cox proportional regression model and the survival analysis were used to evaluate the prognostic risk model. Moreover, the efficiency of prognostic risk model was tested by receiver operating characteristic (ROC) curve analysis based on data from TCGA database and Gene Expression Omnibus (GEO). Besides, the other independent datasets from Human Protein Atlas dataset (HPA) also applied.

RESULTS

13 ARGs (GABARAPL1, ITGA3, USP10, ST13, MAPK9, PRKN, FADD, IKBKB, ITPR1, TP73, MAP2K7, CDKN2A, and EEF2K) with prognostic value were identified in HNSCC patients. Subsequently, a prognostic risk model was established based on 13 ARGs, and significantly stratified HNSCC patients into high- and low-risk groups in terms of overall survival (OS) (HR = 0.379，95% CI: 0.289-0.495, p < 0.0001). The multivariate Cox analysis revealed that this model was an independent prognostic factor (HR = 1.506, 95% CI = 1.330-1.706, P < 0.001). The areas under the ROC curves (AUC) were significant for both the TCGA and GEO, with AUC of 0.685 and 0.928 respectively. Functional annotation revealed that model significantly enriched in many critical pathways correlated with tumorigenesis, including the p53 pathway, IL2 STAT5 signaling, TGF beta signaling, PI3K Ak mTOR signaling by gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA). In addition, we developed a nomogram shown some clinical net could be used as a reference for clinical decision-making.

CONCLUSIONS

Collectively, we developed and validated a novel robust 13-gene signatures for HNSCC prognosis prediction. The 13 ARGs could serve as an independent and reliable prognostic biomarkers and therapeutic targets for the HNSCC patients.

Transcriptome analysis reveals the link between lncRNA-mRNA co-expression network and tumor immune microenvironment and overall survival in head and neck squamous cell carcinoma

Background

As the sixth most common cancer worldwide, head and neck squamous cell carcinoma (HNSCC) develops visceral metastases during the advanced stage of the disease and exhibits a low five-year survival rate. The importance of tumor microenvironment (TME) in tumor initiation and metastasis is widely recognized. In addition, accumulating evidence indicates that long non-coding RNA (lncRNA) is involved in crosstalk between TME and tumor cells. However, the lncRNA-associated regulators modulating the HNSCC microenvironment and progression remain largely unknown.

Methods

The publicly available transcriptome data and matched clinical HNSCC data were collected from The Cancer Genome Atlas (TCGA). Immune scores (ISs) and stromal scores (SSs) of HNSCC TME were calculated using ESTIMATE algorithm. Weighted gene co-expression network analysis (WGCNA) was conducted to determine the co-expressed lncRNAs and protein-coding mRNAs.

Results

Results showed that the high IS HNSCC male patient subgroup exhibited improved survival. Additionally, we identified 169 lncRNAs and 825 protein-coding mRNAs that were differentially expressed in high IS HNSCC samples, with the up-regulated mRNAs displaying enrichment in immune-related biological processes. Notably, we identified a high co-expression lncRNA-mRNA module (i.e., purple module) that showed strong correlation with ISs. This module contained 79 lncRNAs and 442 mRNAs, including 26 lncRNAs and 215 mRNAs showing association between expression and male HNSCC survival. Consistently, 207 of the 215 mRNAs were up-regulated in high IS HNSCC group and were enriched in immune-related signaling pathways. Based on bioinformatics analyses and previous functional assays, certain lncRNAs (e.g., AL365361.1 and PCED1B-AS1) in the purple module likely contributed to the modification of tumor immune microenvironment (TIME) in the high IS HNSCC patients, achieved by regulating transcription of abundant immune-related genes (e.g., CCR7 and TLR8).

Conclusions

In summary, we ascertained a HNSCC male patient subgroup that displayed high ISs and good survival probability. We identified hundreds of genes with specific expression patterns in this HNSCC subgroup as well as a highly co-expressed lncRNA-mRNA module with great potential for the modulation of TIME of HNSCC. Our study provides evidence of a link between the lncRNA-associated gene network, TIME, and HNSCC progression, and highlights potential therapeutic targets for this disease.

The effect of piperlongumine on endothelial and lung adenocarcinoma cells with regulated expression of profilin-1

Purpose

The aim of the study was to evaluate the effect of piperlongumine (2 and 4 µM) on endothelial EA.hy926 and lung adenocarcinoma A549 cells with regulated expression of profilin-1 (PFN1).

Material and methods

The cytotoxicity of alkaloid was evaluated by MTT assay, while cell death was assessed using double staining with annexin V and propidium iodide. Subsequently, the level of PFN1 1) upregulation in EA.hy926 endothelial cells and 2) downregulation in A549 lung adenocarcinoma cells. The next step was the analysis of the effect of PFN1 manipulation on cytoskeletal proteins.

Results

The results showed that piperlongumine may inhibit proliferation of EA.hy926 and A549 cell lines and also induce cell death in a dose-dependent manner. Furthermore, endothelial cells with PFN1 overexpression showed lower sensitivity to alkaloid and strengthening of cell-cell interactions. In the case of A549 cells, loss of PFN1 expression resulted in a lower percentage of early apoptotic cells, reorganization of F-actin and vimentin network, and reduction of migratory potential.

Conclusion

We suggest that upregulation of PFN1 in endothelial cell line may stabilize the cell junctions. In turn, PFN1 downregulation in A549 cells probably suppresses cell migration and sensitizes cells to anticancer agents.

RNAi-mediated inhibition of Lgr5 leads to decreased angiogenesis in gastric cancer

Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) is a novel gastric cancer marker. However, it is unclear whether it can play roles in tumor angiogenesis. In this study, we aim to investigate the role of Lgr5 on gastric cancer angiogenesis. Lgr5, VEGF expression levels and microvessel density (MVD) were detected in tumor tissue. Then, Lgr5 mRNA was downregulated by small interference RNA technique. Western blotting and real-time quantitative PCR (qRT-PCR) were performed to detect the expression of Lgr5 and VEGF protein and mRNA in Lgr5 siRNA-transfected gastric cancer cells. The effect of silencing Lgr5 on angiogenesis was examined by assessing human umbilical vein endothelia cell (HUVEC) capillary tube formation. The results indicated that Lgr5 expression was upregulated in gastric cancer and positively correlated with VEGF (r=0.305, P=0.001) and MVD (r=0.312, P=0.001). Silencing of Lgr5 expression resulted in suppression of VEGF mRNA and protein (all P=0.001). Moreover, when HUVECs were stimulated with conditioned medium from Lgr5 siRNA-transfected gastric cancer cells, tube formation was significantly decreased (2.51 ± 0.19 mm/mm2) compared with the treatment with regular cell culture medium (DMEM) (7.34 ± 0.30 mm/mm2) or medium from control siRNA-transfected cells (7.18 ± 0.33 mm/mm2) (all P=0.001). In conclusion, Lgr5 plays important roles in angiogenesis. Lgr5-specific siRNA could be designed into an effective therapeutic agent to inhibit gastric cancer angiogenesis.

The synergistic antitumor effect of cinobufagin and cisplatin in human osteosarcoma cell line in vitro and in vivo

Cisplatin (CDDP) has been shown to be a promising anticancer drug that is effective against many types of cancer, which include osteosarcoma (OS). However, its therapeutic application is restricted by its toxicity in normal tissues and by side effects caused in patients. Reduction of the toxicity of CDDP is necessary to improve cancer treatment. In the present study, we attempted to clarify how cinobufagin, a traditional Chinese medicine, enhances CDDP-induced cytotoxicity in OS cells. OS 143B cells were treated with cinobufagin and CDDP alone or in combination. After low dose combined treatments with cinobufagin and CDDP, the effects of these therapeutics on cell proliferation, apoptosis, cell cycle, migration, invasion, and involvement in Notch pathway, as well as tumor growth and metastatic capability were determined. It was found that the combination of low doses of cinobufagin and CDDP markedly inhibited cell activity, motility, and induced apoptosis and cell cycle arrest in S phase, as well as suppressing tumor growth, metastasis and prolonging longer survival of nude mice in OS xenograft models compared with the actions of either drug alone or vehicle. The results also demonstrated that cinobufagin plus CDDP significantly suppressed the Notch pathway. The anticancer mechanism of these two drugs may involve intervention in the Notch signaling, which may contribute to inhibit tumor growth. All of these results suggest that application of lower concentration cinobufagin plus CDDP could produce a synergistic antitumor effect and this finding warrants further investigation for its potential clinical applications in human OS patients.

The proteolytic profile of human cancer procoagulant suggests that it promotes cancer metastasis at the level of activation rather than degradation

Proteases are essential for tumour progression and many are over-expressed during this time. The main focus of research was the role of these proteases in degradation of the basement membrane and extracellular matrix (ECM), thereby enabling metastasis to occur. Cancer procoagulant (CP), a protease present in malignant tumours, but not normal tissue, is a known activator of coagulation factor X (FX). The present study investigated the function of CP in cancer progression by focussing on its enzymatic specificity. FX cleavage was confirmed using SDS-PAGE and MALDI-TOF MS and compared to the proteolytic action of CP on ECM proteins, including collagen type IV, laminin and fibronectin. Contrary to previous reports, CP cleaved FX at the conventional activation site (between Arg-52 and Ile-53). Additionally, degradation of FX by CP occurred at a much slower rate than degradation by conventional activators. Complete degradation of the heavy chain of FX was only visible after 24 h, while degradation by RVV was complete after 30 min, supporting postulations that the procoagulant function of CP may be of secondary importance to its role in cancer progression. Of the ECM proteins tested, only fibronectin was cleaved. The substrate specificity of CP was further investigated by screening synthetic peptide substrates using a novel direct CP assay. The results indicate that CP is not essential for either cancer-associated blood coagulation or the degradation of ECM proteins. Rather, they suggest that this protease may be required for the proteolytic activation of membrane receptors.

Head and neck cancer: past, present and future

Head and neck cancer consists of a diverse group of cancers that ranges from cutaneous, lip, salivary glands, sinuses, oral cavity, pharynx and larynx. Each group dictates different management. In this review, the primary focus is on head and neck squamous cell carcinoma (HNSCC) arising from the mucosal lining of the oral cavity and pharynx, excluding nasopharyngeal cancer. Presently, HNSCC is the sixth most prevalent neoplasm in the world, with approximately 900,000 cases diagnosed worldwide. Prognosis has improved little in the past 30 years. In those who have survived, pain, disfigurement and physical disability from treatment have had an enormous psychosocial impact on their lives. Management of these patients remains a challenge, especially in developing countries where this disease is most common. Of all human cancers, HNSCC is the most distressing since the head and neck is the site of the most complex functional anatomy in the human body. Its areas of responsibility include breathing, the CNS, vision, hearing, balance, olfaction, taste, swallowing, voice, endocrine and cosmesis. Cancers that occur in this area impact on these important human functions. Consequently, in treating cancers of the head and neck, the effects of the treatment on the functional outcome of the patient need the most serious consideration. In assessing the success of HNSCC treatment, consideration of both the survival and functional deficits that the patient may suffer as a consequence of their treatment are of paramount importance. For this reason, the modern-day management of head and neck patients should be carried out in a multidisciplinary head and neck clinic.

Prognostic molecular markers in head and neck squamous cell carcinoma in a New Zealand population: matrix metalloproteinase-2 and sialyl Lewis x antigen

OBJECTIVE

The survival rate for head and neck squamous cell carcinoma (HNSCC) is among the lowest of the major cancers and has not substantially improved in the past two decades. Tumours with similar histological features may have widely differing clinical outcomes and thus identification of prognostic and predictive biomarkers may be valuable for determining appropriate clinical management strategies. The objective of this study was to establish the prognostic significance of six molecular markers in HNSCC in a New Zealand population: matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), tissue inhibitor of matrix metalloproteinase-1, sialyl Lewis antigens a and x (sLe(a) , sLe(x) ) and alpha B-crystallin.

METHODS

Retrospective review of 145 sequential HNSCC patients from a tertiary centre with minimum 3 years surveillance. Sections from formalin-fixed paraffin-embedded tumour blocks were immunostained for the molecular markers and scored. Cox regression modelling was used to adjust for potential confounding variables impacting on cancer survival.

RESULTS

Multivariate analysis for individual biomarkers, controlling for age, sex, tumour grade, N-stage, T-stage, tumour site, smoking history and alcohol use, revealed poorer survival with tumour expression of MMP-2 (hazard ratio = 1.98, 95% confidence interval: 1.11-3.52, P = 0.021) and sLe(x) (hazard ratio = 3.22, 95% confidence interval: 1.33-7.80, P = 0.010). A stepwise analysis showed that MMP-2 and sLe(x) were independently prognostic after covariate adjustment.

CONCLUSIONS

MMP-2 and sLe(x) were negative prognostic markers for survival in these HNSCC patients. This offers opportunities for clinical trials to reduce the risk of nodal and distant metastases through blocking tumour cell adhesion to endothelium.

TWIST1 is a molecular marker for a poor prognosis in oral cancer and represents a potential therapeutic target

BACKGROUND

Locoregional recurrence and distant metastases are ominous events in patients with advanced oral squamous cell carcinoma (OSCC). The objective of this study was to identify functional biomarkers that are predictive of OSCC progression to metastasis.

METHODS

The expression profile of a network of epithelial-mesenchymal transition (EMT) genes was investigated in a large cohort of patients with progressive OSCC using a complimentary DNA microarray platform coupled to quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical analyses. Therapeutic potential was investigated in vitro and in vivo using an orthotopic mouse model of metastatic OSCC growing in the tongue microenvironment.

RESULTS

Among deregulated EMT genes, the Twist-related protein 1 (TWIST1) transcription factor and several of its regulated genes were significantly overexpressed across advanced stages of OSCC. This result was corroborated by the clinical observation that Twist1 up-regulation predicted the occurrence of lymph node and lung metastases as well as poor patient survival. In support of Twist1 as a driver of OSCC progression, the up-regulation of Twist1 was observed in cells isolated from patients with metastatic OSCC. The inhibition of Twist1 in these metastatic cells induced a potent inhibition of cell invasiveness in vitro as well as progression in vivo.

CONCLUSIONS

The current results provide evidence for the prognostic value and therapeutic potential of a network of Twist genes in patients with advanced OSCC.

Mast cell chymase is present in uterine cervical carcinoma and it detaches viable and growing cervical squamous carcinoma cells from substratum in vitro

Increased numbers of mast cells is a typical feature of a variety of human cancers. The major mediators in the secretory granules of the MC(TC) type of mast cells, serine proteinases tryptase and chymase, may be involved in squamous cell carcinoma (SCC) lesions by inducing matrix remodeling and epithelial cell detachment. The objective of this study was to analyze immunohistochemically whether MC(TC) mast cells as well as protease inhibitors, squamous cell carcinoma antigens (SCCAs), are present in the uterine cervical SCC. In addition, the effect of tryptase and chymase on uterine cervical SCC cell lines was studied in vitro. Here we report that tryptase- and chymase-positive mast cells are present in significant numbers in the peritumoral stroma of SCC lesions. Also, weak SCCA-2 immunoreactivity is observed in the SCC lesions, but only SCCA-1 in uterine cervical specimens with nonspecific inflammation. In cell cultures, especially chymase, but not tryptase, was shown to induce effective detachment of viable, growing and non-apoptotic SiHa SCC cells from substratum. Chymase also detached viable ME-180 SCC cells from substratum as well as degraded fibronectin. In contrast, normal keratinocytes underwent apoptotic cell death after similar prolonged chymase treatment. No inhibition of chymase was detected by SiHa cell sonicates nor did these cells express marked SCCA immunopositivity. MC(TC) mast cells containing tryptase and chymase are present in the peritumoral stroma of uterine cervical SCC and the malignant cells are only weakly immunoreactive for the chymase inhibitor SCCA-2. It is chymase that appears to be capable of inducing effective detachment of viable and growing SCC cells and therefore, it may release SCC cells from a tumor leading to spreading of malignant cells.

GHRH antagonists reduce the invasive and metastatic potential of human cancer cell lines in vitro

We investigated the effect of a GHRH antagonist, MIA-602on the metastatic cascade in vitro of three human cancers, DBTRG-05 glioblastoma, MDA-MB-468 estrogen-independent breast, and ES-2 clear cell ovarian cancer. GHRH receptors and their main splice variant, SV1 were detected on all three cell lines. After treatment with MIA-602, the cell viability decreased significantly, significant inhibition of cell invasion was observed and the release of MMPs was significantly decreased. The attachment of cancer cells to fibronectin and matrigel was severely hindered. Wound-healing experiments demonstrated a reduced cellular motility in all three cell lines. The upregulation of caveolin-1 and E-cadherin,and thepowerful downregulation of NF-kappaB and beta-catenin was detected. Our study suggests that the clinical application of highly potent GHRH antagonists in cancer therapy would be desirable since they inhibit proliferation and metastasis development as well.

Vasoactive intestinal peptide behaves as a pro-metastatic factor in human prostate cancer cells

BACKGROUND

There is little known on the involvement of vasoactive intestinal peptide (VIP) in the metastatic cascade of human prostate cancer, that is, cell proliferation, cell-cell adhesion, extracellular-matrix degradation, and migration/invasion. Here we evaluated the expression of related biomarker proteins (cyclin D1, metalloproteinases MMP-2 and MMP-9, and E-cadherin) in human androgen-dependent (LNCaP) and independent (PC3) prostate cancer cells.

METHODS

Reverse transcriptase (RT)-polymerase chain reaction (PCR), gelatin zymography, Western blotting, confocal immunofluorescence microscopy, and assays on cell proliferation, adhesion, wound-healing, migration and random homing were performed.

RESULTS

VIP increased cell proliferation and cyclin D1 expression whereas it decreased cell adhesion and E-cadherin expression in LNCaP and PC3 cells. VIP enhanced the gelatinolytic activity of MMP-2 and MMP-9. Semiquantitative RT-PCR assays showed that VIP stimulated mRNA levels of these MMPs and suppressed mRNA levels of its inhibitory protein RECK. VIP promoted cell invasion and migration, and the responses were faster according to the most aggressive status in cancer progression (androgen-independence). The involvement of nuclear factor-kappaB (NF-kappaB) was demonstrated since the anti-inflammatory agent curcumin blocked VIP effects on the above biomarkers in both cell lines.

CONCLUSIONS

Taken together, these results and the presence of kappaB sites on gene promoter of cyclin D1, MMPs and, possibly, E-cadherin suggest that VIP may act as a cytokine in an early metastatic stage of human prostate cancer through the NF-kappaB/MMPs-RECK/E-cadherin system. Our findings may help to define novel targets and agents with potential usefulness in prostate cancer therapy.

Toll-like receptor agonists induce inflammation and cell death in a model of head and neck squamous cell carcinomas

Toll-like receptors (TLRs) are increasingly implicated in the pathogenesis of cancer. The present study describes TLR expression and function in healthy and malignant airway epithelial cells. The squamous cell carcinoma cell line Detroit-562 was compared with the healthy bronchial epithelial cell line NL-20 and primary human nasal epithelial cells (HNECs). TLR2, TLR3 and TLR5 were present in primary head and neck squamous cell carcinomas (HNSCCs). Consistent with this, Detroit-562 expressed TLR2, TLR3 and TLR5, whereas NL-20 expressed mainly TLR3 and HNECs expressed TLR2-5. In Detroit-562, Pam(3)CSK(4), poly(I:C) and flagellin, ligands for TLR2, TLR3 and TLR5, respectively, induced an up-regulation of intercellular adhesion molecule 1 (ICAM-1), an increase in interleukin (IL)-6 and IL-8 secretion and a decrease in cell viability. Additionally, poly(I:C) affected IL-1beta production and the migratory behaviour of Detroit-562. NL-20 responded with a slight increase in IL-8 secretion upon poly(I:C) stimulation. Poly(I:C) induced a small increase in IL-1beta, IL-6 and IL-8 production in HNECs, while Pam(3)CSK(4) increased viability. The TLR signalling was transcription-dependent, but the pathways involved differed among TLRs as well as cells. In Detroit-562, TLR2 and TLR5 activation was mediated via c-jun N-terminal kinase (JNK)-, p38-, phosphatidylinositol 3-kinase (PI3K)- and nuclear factor (NF)-kappaB-related pathways, while TLR3 was dependent on NF-kappaB. In NL-20, TLR3 signalled via p38, and in HNECs, NF-kappaB, JNK and extracellular signal-regulated kinase (ERK) appeared to be involved. We found that TLR agonists induced a robust response in HNSCCs, characterized by generation of inflammation and cell death. A similar response was not seen in normal epithelial cells. Thus, the TLR system should be considered an important target in future antitumour immunotherapy.

Inhibition of lung tumor colonization and cell migration with the disintegrin crotatroxin 2 isolated from the venom of Crotalus atrox

Disintegrins are low molecular weight proteins (4-15 kDa) with an RGD binding region at their binding loop. Disintegrin and disintegrin-like proteins are found in the venom of four families of snakes: Atractaspididae, Elapidae, Viperidae, and Colubridae. This report describes the biological activity of a disintegrin, crotatroxin 2, isolated by a three-step chromatography procedure from the venom of the Western diamondback rattlesnake (Crotalus atrox). The intact molecular mass for crotatroxin 2 was 7.384 kDa and 71 amino acids. Crotatroxin 2 inhibited human whole blood platelet aggregation with an IC(50) of 17.5 nM, inhibited cell (66.3p) migration by 63%, and inhibited experimental lung tumor colonization in BALB/c mice at 1000 microg/kg. Our data suggest that while crotatroxin 2 inhibits platelet aggregation, cancer cell migration, and lung tumor colonization, it is done via different integrins.

C-terminal Src kinase controls development and maintenance of mouse squamous epithelia

Carboxy-terminal Src kinase (Csk) is a negative regulator of Src family kinases, which play pivotal roles in controlling cell adhesion, migration, and cancer progression. To elucidate the in vivo role of Csk in epithelial tissues, we conditionally inactivated Csk in squamous epithelia using the keratin-5 promoter/Cre-loxP system in mice. The mutant mice developed apparent defects in the skin, esophagus, and forestomach, with concomitant hyperplasia and chronic inflammation. Histology of the mutant epidermis revealed impaired cell-cell adhesion in basal cell layers. Analysis of primary keratinocytes showed that the defective cell-cell adhesion was caused by cytoskeletal remodeling via activation of the Rac1 pathway. Mutant keratinocytes also showed elevated expression of mesenchymal proteins, matrix metalloproteinases (MMPs), and the proinflammatory cytokine TNF-alpha. Inhibition of the expression of TNF-alpha and MMP9 by the anti-inflammatory reagent FK506 could cure the epidermal hyperplasia, suggesting a causal link between inflammation and epidermal hyperplasia. These observations demonstrate that the Src/Csk circuit plays crucial roles in development and maintenance of epithelia by controlling cytoskeletal organization as well as phenotypic conversion linked to inflammatory events.

Photodynamic therapy down-regulates the invasion promoting factors in human oral cancer

Squamous cell carcinomas of the head and neck are characterized by their high tendency for invasion and metastasis. Several studies have identified the roles of matrix metalloproteinases (MMPs), vascular endothelial growth factors (VEGF) and urokinase plasminogen activators (uPA) in this process. Photodynamic Therapy (PDT) is an emerging treatment currently in clinical practice for the treatment of early cancer. Here we evaluate, in vitro, the influence of PDT on the expression of these molecules. A series of human keratinocyte cell lines derived from human oral squamous cell carcinomas (OSCC) were used as the PDT 'targets' in this study. Each cell line was subjected to sublethal dose of PDT. Activity of MMP-2, MMP-9, MMP-13, uPA and VEGF were evaluated at protein levels using zymography and ELISA on culture medium. For uPA, a chromogenic assay was performed. Gelatin zymography results revealed that, in control medium, MMP-9 and MMP-2 were secreted in proform. MMP-2 was highly expressed by H376 cells while VB6 and UP cells relatively show similar MMP-2 with comparatively low expression. For MMP-9, the latent type was highly expressed by VB6 cells and only slightly by H376, while active-MMP-9 was expressed by VB6 cell line only. Following PDT, both active and latent MMP-2 and MMP-9 were down regulated by UP and VB6 cells (p<0.001), while H376 showed an increase in active-MMP-2. These observations were supported by ELISA. This study has demonstrated that, PDT causes the suppression of factors responsible for tumour invasion which may be of therapeutic value.

Expression of KAI1 and tenascin, and microvessel density are closely correlated with liver metastasis of gastrointestinal adenocarcinoma

AIM

To seek good markers to predict invasion and metastasis of gastrointestinal adenocarcinoma (GIA).

METHODS

Expression of KAI1 and tenascin were examined on tissue microarrays containing gastric adenocarcinoma (n = 98), colorectal adenocarcinoma (n = 125), gastric adjacent non-cancerous mucosa (n = 95) and colorectal adjacent non-cancerous mucosa (n = 112) by immunostaining. Microvessel density (MVD) in GIA was labelled using anti-CD34 antibody by immunostaining. Expression of KAI1 and tenascin, and MVD were compared with clinicopathological features of tumours, including PTEN (phosphatase and tensin homology deleted from human chromosome 10) and EMMPRIN (extracellular matrix metalloproteinase inducer) expression.

RESULTS

KAI1 expression was higher in GIAs than in their adjacent non-cancerous mucosa (p<0.05). KAI1 and tenascin expression showed a significantly negative association with liver metastasis of GIA (p<0.05), but not with depth of invasion, venous invasion or lymph node metastasis (p>0.05). A significantly negative relationship was observed between EMMPRIN and tenascin expression in GIA (p<0.05). MVD was positively correlated with depth of invasion, venous invasion, lymph node metastasis and liver metastasis of tumours (p<0.05), whereas it was negatively correlated with PTEN expression (p<0.05).

CONCLUSIONS

Up-regulated KAI1 expression may play an important part in malignant transformation of gastrointestinal epithelial cells. Reduced expression of KAI1 and tenascin might underlie the molecular basis of liver metastasis of GIA. Angiogenesis is a key event in the invasion and metastasis of GIA. These markers might be used to indicate liver metastasis of GIA in clinicopathological practice.

Anandamide inhibits adhesion and migration of breast cancer cells

The endocannabinoid system regulates cell proliferation in human breast cancer cells. We reasoned that stimulation of cannabinoid CB1 receptors could induce a non-invasive phenotype in breast metastatic cells. In a model of metastatic spreading in vivo, the metabolically stable anandamide analogue, 2-methyl-2'-F-anandamide (Met-F-AEA), significantly reduced the number and dimension of metastatic nodes, this effect being antagonized by the selective CB1 antagonist SR141716A. In MDA-MB-231 cells, a highly invasive human breast cancer cell line, and in TSA-E1 cells, a murine breast cancer cell line, Met-F-AEA inhibited adhesion and migration on type IV collagen in vitro without modifying integrin expression: both these effects were antagonized by SR141716A. In order to understand the molecular mechanism involved in these processes, we analyzed the phosphorylation of FAK and Src, two tyrosine kinases involved in migration and adhesion. In Met-F-AEA-treated cells, we observed a decreased tyrosine phosphorylation of both FAK and Src, this effect being attenuated by SR141716A. We propose that CB1 receptor agonists inhibit tumor cell invasion and metastasis by modulating FAK phosphorylation, and that CB1 receptor activation might represent a novel therapeutic strategy to slow down the growth of breast carcinoma and to inhibit its metastatic diffusion in vivo.