Tumor invasion and metastases: biochemical mechanisms

Lysyl Oxidase Mechanisms to Mediate Gastrointestinal Cancer Progression

Background

Malignancy is a complex process resulting from different changes such as extracellular matrix (ECM) remodeling and stiffness. One of the important enzymes that contribute to ECM remodeling is lysyl oxidase (Lox) that is overexpressed in different types of human cancers. Because of the high prevalence and poor survival of gastrointestinal (GI) malignancies in this review, we discuss the association between Lox activity and the progression of GI cancers. Lox proteins are a group of extracellular enzymes that catalyzed the cross-linking of collagen and elastin, so they have important roles in the control of structure and homeostasis of ECM. Abnormal activation and expression of the Lox family of proteins lead to changes in the ECM toward increased rigidity and fibrosis. Stiffness of ECM can contribute to the pathogenesis of cancers.

Summary

Dysregulation of Lox expression is a factor in both fibrotic diseases and cancer. ECM stiffness by Lox overactivity creates a physical barrier against intratumoral concentration of chemotherapeutic drugs and facilitates cancer inflammation, angiogenesis, and metastasis.

Key Message

Because of the roles of Lox in GI cancers, development targeting Lox protein isotypes may be an appropriate strategy for treatment of GI cancers and improvement in survival of patients.

Elucidating the Association Between the Upregulation of Angiotensin Type 1-Receptors and the Development of Gastrointestinal Malignancies

The renin-angiotensin system (RAS) is a major regulator of body fluid hemostasis and blood pressure. Angiotensin type 1 receptors (AT1R) are one of the major components of this system and are widely expressed in different organs, including the gastrointestinal (GI) system. Very little known about the physiological roles of AT1R in GI tract but evidence has reported that local AT1Rs are upregulated in pathological conditions like GI malignancies and play role in stimulation of signaling pathways associated with GI cancers progression. AT1Rs axes signaling in tumor microenvironments stimulate inflammation and facilitate vascularization around the tumor cell to display invasive behavior. AT1Rs in stroma cells promote tumor-associated angiogenesis by upregulated of vessel endothelial growth factor (VEGF). Also, AT1Rs by the activation of molecular mechanisms such as PI3/Akt/NF-κB pathways increase the invasion of tumor cells. Experimental and clinical studies have reported that AT1R antagonists have beneficial influences by increasing the survival of patients with GI malignancies and reduction in the proliferation of GI cancer cell lines in vitro, and the growth and metastasis of tumors in vivo, therefore, AT1Rs antagonist have the potential for future anticancer strategies. This review focuses on the pathological roles of AT1Rs in GI malignancies.

Vascular Endothelial Growth Factor (Vegf) and Other Common Tissue Prognostic Indicators in Breast Cancer: A Case-Control Study

VEGF is a specific mitogen and survival factor for endothelial cells and a key promoter of angiogenesis in physiological and pathological conditions. Nevertheless, VEGF tissue evaluation in cancer patients as a prognostic factor compared to the conventional histological and biological parameters is still controversial. In this case-control study, tissue VEGF was retrospectively determined by immunohistochemistry and related to T, N, ER, PgR, c-erbB-2, p53, MIB-1 and cyclin D1 in 129 breast cancer patients. Seventy-four of these patients had developed distant metastases postoperatively. The remaining 55 patients had remained disease-free >10 years after surgery. In 17 (13%) of the 129 patients (six with distant metastases and eleven disease-free) tissue and plasma VEGF were concomitantly evaluated. In univariate analysis no significant differences in VEGF and tumor size were found between metastatic and disease-free patients, whereas there were significant differences in N, ER, PgR, c-erbB-2, p53, MIB-1 and cyclin D1 (p ranging from 0.001 to 0.0001). In multivariate analysis VEGF showed less significance than N, ER, c-erbB-2, MIB-1 and cyclin D1 (p=0.012, p=0.007, p=0.005, p=0.005, p=0.002 and p=0.001, respectively). VEGF was a significant unfavorable prognostic indicator only in the N+ subset (p=0.015), while ER (p=0.05 and p=0.021) and MIB-1 (p=0.031 and p=0.022) were significant in both the N+ and N– subgroups. In multivariate analysis in the 74 metastatic cases VEGF did not show any significance in relation to disease-free interval and overall survival from the time of mastectomy and from the time of relapse, whereas N and PgR did (p ranging from 0.018 to 0.001). In conclusion, tissue VEGF does not seem a suitable candidate to replace conventional histological and other common biological prognostic factors in breast cancer.

Circulating soluble intercellular adhesion molecule-1 in lung cancer: a systematic review

Soluble intercellular adhesion molecule-1(sICAM-1) has been implicated in tumor progression and metastasis. However the expression of circulating sICAM-1 as well as its diagnostic and prognostic value in patients with lung cancer remains controversial. We performed an electronic database (including PubMed, Web of Science, and Medline) search with the terms "ICAM", "intercellular adhesion molecule" and "lung cancer", and summarized the results of eligible studies in order to review the expression of sICAM-1 as well as its clinical significance in lung cancer. According to our literature search, we conducted a final analysis of 1258 patients from 16 studies. And we revealed that the circulating concentration of sICAM-1 in lung cancer patients was significantly higher than that in healthy controls. Additionally, baseline sICAM-1 levels apparently were associated with ECOG performance status, gender, histology type and disease stages. Furthermore, there seems to be a significantly inverse association between sICAM-1 levels, prognosis and response rate in NSCLC patients. In conclusion, sICAM-1 appeared to be a potential diagnostic and prognostic biomarker in lung cancer patients. Additional prospective studies are required to confirm this issue.

The development of a malignant tumor is due to a desperate asexual self-cloning process in which cancer stem cells develop the ability to mimic the genetic program of germline cells

To date there is no explanation why the development of almost all types of solid tumors occurs sharing a similar scenario: (1) creation of a cancer stem cell (CSC), (2) CSC multiplication and formation of a multicellular tumor spheroid (TS), (3) vascularization of the TS and its transformation into a vascularized primary tumor, (4) metastatic spreading of CSCs, (5) formation of a metastatic TSs and its transformation into metastatic tumors, and (6) potentially endless repetition of this cycle of events. The above gaps in our knowledge are related to the biology of cancer and specifically to tumorigenesis, which covers the process from the creation of a CSC to the formation of a malignant tumor and the development of metastases. My Oncogerminative Theory of Tumorigenesis considers tumor formation as a dynamic self-organizing process that mimics a self-organizing process of early embryo development. In the initial step in that process, gene mutations combined with epigenetic dysregulation cause somatic cells to be reprogrammed into CSCs, which are immortal pseudo-germline cells. Mimicking the behavior of fertilized germline cells, the CSC achieves immortality by passing through the stages of its life-cycle and developing into a pseudo-blastula-stage embryo, which manifests in the body as a malignant tumor. In this view, the development of a malignant tumor from a CSC is a phenomenon of developmental biology, which we named a desperate asexual self-cloning event. The theory explains seven core characteristics of malignant tumors: (1) CSC immortality, (2) multistep development of a malignant tumor from a single CSC, (3) heterogeneity of malignant tumor cell populations, (4) metastatic spread of CSCs, (5) invasive growth, (6) malignant progression, and (7) selective immune tolerance toward cancer cells. The Oncogerminative Theory of Tumorigenesis suggests new avenues for discovery of revolutionary therapies to treat, prevent, and eradicate cancer.

Laminin-111-derived peptides and cancer

Laminin-111 is a large trimeric basement membrane glycoprotein with many active sites. In particular, four peptides active in tumor malignancy studies have been identified in laminin-111 using a systematic peptide screening method followed by various assays. Two of the peptides (IKVAV and AG73) are found on the α1 chain, one (YIGSR) of the β1 chain and one (C16) on the γ1 chain. The four peptides have distinct activities and receptors. Since three of the peptides (IKVAV, AG73 and C16) strongly promote tumor growth, this may explain the potent effects laminin-111 has on malignant cells. The peptide, YIGSR, decreases tumor growth and experimental metastasis via a 32/67 kD receptor while IKVAV increases tumor growth, angiogenesis and protease activity via integrin receptors. AG73 increases tumor growth and metastases via syndecan receptors. C16 increases tumor growth and angiogenesis via integrins. Identification of such sites on laminin-111 will have use in defining strategies to develop therapeutics for cancer.

Reverse phase protein microarrays advance to use in clinical trials

Individualizing cancer therapy for molecular targeted inhibitors requires a new class of molecular profiling technology that can map the functional state of the cancer cell signal pathways containing the drug targets. Reverse phase protein microarrays (RPMA) are a technology platform designed for quantitative, multiplexed analysis of specific phosphorylated, cleaved, or total (phosphorylated and non-phosphorylated) forms of cellular proteins from a limited amount of sample. This class of microarray can be used to interrogate tissue samples, cells, serum, or body fluids. RPMA were previously a research tool; now this technology has graduated to use in research clinical trials with clinical grade sensitivity and precision. In this review we describe the application of RPMA for multiplexed signal pathway analysis in therapeutic monitoring, biomarker discovery, and evaluation of pharmaceutical targets, and conclude with a summary of the technical aspects of RPMA construction and analysis.

Cell adhesion molecules: role and clinical significance in cancer

There is a growing body of evidence suggesting that alterations in the adhesion properties of neoplastic cells endow them with an invasive and migratory phenotype. Indeed, changes in the expression or function of cell adhesion molecules have been implicated in all steps of tumor progression, including detachment of tumor cells from the primary site, intravasation into the blood stream, extravasation into distant target organs, and formation of the secondary lesions. This review presents recent data regarding the role of cell adhesion molecules in tumor development and progress with concern to their clinical exploitation as potential biomarkers in neoplastic diseases.

The tumor microenvironment: the making of a paradigm

What has been will be again, what has been done will be done again; there is nothing new under the sun

(Ecclesiastes 1:9)

Stephen Paget was the conceptual father of the role played by the Tumor Microenvironment (TME) in tumor progression. The focus of this essay is the developmental phase of the post Paget TME research. Attempts will be made to highlight some of the pioneering work of scientists from the late sixties through the eighties of last century who laid the foundations for the contemporary scientific achievements of TME research but whose ground breaking studies are rarely cited. This review should serve as a small tribute to their great work.

Cyclic AMP-responsive element binding protein- and nuclear factor-kappaB-regulated CXC chemokine gene expression in lung carcinogenesis

The recognition of the importance of angiogenesis in tumor progression has led to the development of antiangiogenesis as a new strategy for cancer treatment and prevention. By modulating tumor microenvironment and inducing angiogenesis, the proinflammatory cytokine interleukine (IL)-1beta has been reported to promote tumor development. However, the factors mediating IL-1beta-induced angiogenesis in non-small cell lung cancer (NSCLC) and the regulation of these angiogenic factors by IL-1beta are less clear. Here, we report that IL-1beta up-regulated an array of proangiogenic CXC chemokine genes in the NSCLC cell line A549 and in normal human tracheobronchial epithelium cells, as determined by microarray analysis. Further analysis revealed that IL-1beta induced much higher protein levels of CXC chemokines in NSCLC cells than in normal human tracheobronchial epithelium cells. Conditioned medium from IL-1beta-treated A549 cells markedly increased endothelial cell migration, which was suppressed by neutralizing antibodies against CXCL5 and CXCR2. We also found that IL-1beta-induced CXC chemokine gene overexpression in NSCLC cells was abrogated with the knockdown of cyclic AMP-responsive element binding protein (CREB) or nuclear factor kappaB (NF-kappaB). Moreover, the expression of the CXC chemokine genes as well as CREB and NF-kappaB activities was greatly increased in the tumorigenic NSCLC cell line compared with normal, premalignant immortalized or nontumorigenic cell lines. A disruptor of the interaction between CREB-binding protein and transcription factors such as CREB and NF-kappaB, 2-naphthol-AS-E-phosphate (KG-501), inhibited IL-1beta-induced CXC chemokine gene expression and angiogenic activity in NSCLC. We propose that targeting CREB or NF-kappaB using small-molecule inhibitors, such as KG-501, holds promise as a preventive and/or therapeutic approach for NSCLC.

Serum levels of intercellular adhesion molecule ICAM-1 and E-selectin in advanced stage non-small cell lung cancer

Cell adhesion is a basic count in inter- and intra-cellular communication and plays an important role in tumor progression. This study was conducted to investigate the serum levels of intercellular adhesion molecule (ICAM-1) and E-selectin in patients with advanced stage non-small cell lung cancer (NSCLC) and the relationships with known prognostic parameters and therapy. These serum factors were measured of 57 NSCLC patients pathologically verified before and after chemotherapy in comparison with 24 healthy controls by using ELISA method. Serum levels of ICAM-1 were increased significantly in NSCLC patients compared with the healthy controls (P = 0.006). However, serum E-selectin levels were not significantly different from healthy control groups (0.643). No statistically significant relationships were found between investigated all serum parameters and various characteristics of patients, and the diseases such as stage and tumor burden. Likewise, we also found no correlation between serum ICAM-1 and E-selectin (P = 0.78). We found that serum ICAM-1 levels were decreased owing to the chemotherapy effect, independently from chemotherapy response. However, serum E-selectin levels were not changed by the chemotherapy effect. The median survival of all patients was 11.9 months and 1-year survival rate was 47.6%. We found that patients performance status (P = 0.013), age (P = 0.015), and weight loss (P = 0.007) were prognostic factors for survival. Serum E-selectin levels showed a trend (P = 0.08) related to worse prognosis, however serum ICAM-1 levels were determined as ineffective on survival (P = 0.11). Multivariate analysis revealed that only weight loss (P = 0.005) and E-selectin levels (P = 0.002) remained as an independent prognostic factor for survival in patients with advanced NSCLC. In conclusion, our data suggest that higher serum ICAM-1 can be useful for diagnosis while E-selectin levels have prognostic significance and could be a potential prognostic factor in NSCLC patients.

Laser capture microdissection technology

Deciphering the cellular and molecular interactions that drive disease within the tissue microenvironment holds promise for discovering drug targets of the future. In order to recapitulate the in vivo interactions through molecular analysis, one must be able to analyze specific cell populations within the context of their heterogeneous tissue microecology. Laser capture microdissection is a method to procure subpopulations of tissue cells under direct microscopic visualization. Laser capture microdissection technology can harvest the cells of interest directly or can isolate specific cells by cutting away unwanted cells to give histologically pure enriched cell populations. A variety of downstream applications exist: DNA genotyping and loss-of-heterozygosity analysis, RNA transcript profiling, cDNA library generation, mass spectrometry proteomics discovery and signal pathway profiling.

Laser-capture microdissection

Deciphering the cellular and molecular interactions that drive disease within the tissue microenvironment holds promise for discovering drug targets of the future. In order to recapitulate the in vivo interactions thorough molecular analysis, one must be able to analyze specific cell populations within the context of their heterogeneous tissue microecology. Laser-capture microdissection (LCM) is a method to procure subpopulations of tissue cells under direct microscopic visualization. LCM technology can harvest the cells of interest directly or can isolate specific cells by cutting away unwanted cells to give histologically pure enriched cell populations. A variety of downstream applications exist: DNA genotyping and loss-of-heterozygosity (LOH) analysis, RNA transcript profiling, cDNA library generation, proteomics discovery and signal-pathway profiling. Herein we provide a thorough description of LCM techniques, with an emphasis on tips and troubleshooting advice derived from LCM users. The total time required to carry out this protocol is typically 1-1.5 h.

Single cell adhesion measuring apparatus (SCAMA): application to cancer cell lines of different metastatic potential and voltage-gated Na+ channel expression

We have developed a simple yet effective apparatus, based upon negative pressure directed to the tip of a micro-pipette, to measure the adhesiveness of single cells. The "single cell adhesion measuring apparatus" (SCAMA) could differentiate between the adhesion of strongly versus weakly metastatic cancer cells as well as normal cells. Adhesion was quantified as "detachment negative pressure" (DNP) or "DNP relative to cell size" (DNPR) where a noticeable difference in cell size was apparent. Thus, for rat and human prostate and human breast cancer cell lines, adhesiveness (DNPR values) decreased in line with increased metastatic potential. Using the SCAMA, we investigated the effect of tetrodotoxin (TTX), a specific blocker of voltage-gated Na(+) channels (VGSCs), on the adhesion of rat and human prostate cancer cell lines of markedly different metastatic potential. Following pretreatment with TTX (48 h with 1 microM), the adhesion values for the Mat-LyLu cells increased significantly 4.3-fold; there was no effect on the AT-2 cells. For the strongly metastatic PC-3M cells, TTX treatment caused a significant (approximately 30%) increase in adhesion. The adhesion of PNT2-C2 ("normal") cells was not affected by the TTX pretreatment. The TTX-induced increase in the adhesiveness of the strongly metastatic cells was consistent with the functional VGSC expression in these cells and the proposed role of VGSC activity in metastatic cell behaviour. In conclusion, the SCAMA, which can be constructed easily and cheaply, offers a simple and effective method to characterise single-cell adhesion and its modulation.

High serum vascular endothelial growth factor levels predict poor prognosis after radiofrequency ablation of hepatocellular carcinoma: importance of tumor biomarker in ablative therapies

BACKGROUND

Radiofrequency ablation (RFA) is a recently developed treatment for hepatocellular carcinoma (HCC). Thus far, the prognostic impact of tumor biomarkers has not been evaluated in this treatment. High serum level of vascular endothelial growth factor (VEGF) has been shown to predict microscopic vascular invasion and metastasis in HCC. This study investigated the prognostic significance of pre-treatment serum VEGF level in patients with HCC undergoing RFA treatment.

METHODS

Serum VEGF levels were measured using enzyme-linked immunosorbent assay in 120 patients with HCC undergoing RFA, and in 15 healthy controls. Serum VEGF levels were correlated with clinicopathological features of the HCC patients. The prognostic significance of serum VEGF levels was assessed by univariate and multivariate analyses.

RESULTS

The median serum VEGF level in the HCC patients was 240 pg/mL (range 17-1162), significantly higher than that of healthy controls (p = .024). The serum VEGF levels were significantly correlated with platelet counts (r = .487, p < .001) but not other clinicopathological features. Patients with serum VEGF level > 240 pg/mL had worse overall and recurrence-free survival compared with those with serum VEGF level > 240 pg/mL (p = .005 and .002, respectively). By multivariate analysis, serum VEGF level was a significant prognostic factor of both overall and recurrence-free survival.

CONCLUSIONS

High pre-treatment serum VEGF levels predict poor prognosis after RFA of HCC. This study highlights the importance of tumor biomarker as a prognostic predictor in ablative therapy for HCC, which has an intrinsic problem of unavailability of histopathological prognostic features.

Clinical implications of angiogenesis in cancers

Angiogenesis plays an important role in the growth and progression of cancer. The regulation of tumor angiogenesis depends on a net balance of angiogenic factors and antiangiogenic factors, which are secreted by both tumor cells and host-infiltrating cells. Numerous studies have indicated that assessment of angiogenic activity by either microvessel density or expression of angiogenic factors in cancer can provide prognostic information independent of conventional clinicopathological factors such as tumor staging. Some studies also suggested that assessment of tumor angiogenesis may predict cancer response to chemotherapy or radiotherapy. However, the most important clinical implication of tumor angiogenesis is the development of a novel strategy of anticancer therapy targeting tumor vessels instead of cancer cells. Antiangiogenic therapy aims to inhibit the growth of tumor, and current evidence suggests that it works best in combination with conventional cytotoxic chemotherapy. Recently, a monoclonal antibody against vascular endothelial growth factor, which is one of the most potent angiogenic factors, has been approved for clinical use in colorectal cancer patients after a clinical trial confirmed that combining the antibody with standard chemotherapy regimen could prolong patient survival. The clinical implications of angiogenesis in cancer are reviewed in this article.

Microbubble-enhanced ultrasound exposure improves gene transfer in vascular endothelial cells

AIM: To explore the effects of ultrasound exposure combined with microbubble contrast agent (SonoVue) on the permeability of the cellular membrane and on the expression of plasmid DNA encoding enhanced green fluorescent protein (pEGFP) transfer into human umbilical vein endothelial cells (HUVECs).

METHODS: HUVECs with fluorescein isothiocyanate-dextran (FD500) and HUVECs with pEGFP were exposed to continuous wave (1.9 MHz, 80.0 mW/cm²) for 5 min, with or without a SonoVue. The percentage of FD500 taken by the HUVECs and the transient expression rate of pEGFP in the HUVECs were examined by fluorescence microscopy and flow cytometry, respectively.

RESULTS: The percentage of FD500-positive HUVECs in the group of ultrasound exposure combined with SonoVue was significantly higher than that of the group of ultrasound exposure alone (24.0% ± 5.5% vs 66.6% ± 4.1%, P < 0.001). Compared with the group of ultrasound exposure alone, the transfection expression rate of pEGFP in HUVECs was markedly increased with the addition of SonoVue (16.1% ± 1.9% vs 1.5% ± 0.2%, P < 0.001). No statistical significant difference was observed in the HUVECs survival rates between the ultrasound group with and without the addition of SonoVue (94.1% ± 2.3% vs 91.1% ± 4.1%).

CONCLUSION: The cell membrane permeability of HUVECs and the transfection efficiency of pEGFP into HUVECs exposed to ultrasound are significantly increased after addition of an ultrasound contrast agent without obvious damage to the survival of HUVECs. This non-invasive gene transfer method may be a useful tool for clinical gene therapy of hepatic tumors.

Immunohistochemical study of the expression of adhesion molecules in ovarian serous neoplasms

To clarify possible roles of adhesion molecules including E-cadherin, beta- and gamma-catenin, CD44s, CD44v6, CD56, and CD99 in ovarian serous neoplasms, an immunohistochemical study was undertaken for 23 benign, 40 borderline, and 95 malignant ovarian serous neoplasms using tissue microarray (TMA). Significantly reduced expression of E-cadherin, and overexpression of CD44s, CD56, and CD99 were more frequently observed in adenocarcinomas than in benign and borderline tumors. Expression of CD44v6 and nuclear beta- and gamma-catenin were detected only in borderline tumors and adenocarcinomas. Reduced expression of E-cadherin was also correlated with high tumor grade (P=0.03), presence of peritoneal seeding (P=0.03), and low overall survival rate (P=0.02). Overexpression of CD44s was significantly associated with high tumor grade (P=0.04), advanced stage (P=0.03), and low overall survival rate (P=0.02). CD56 was increasingly expressed in the case of advanced stage (P=0.005) and peritoneal seeding (P=0.001). Nuclear staining for gamma-catenin was correlated with tumor progression (P=0.004) and advanced International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.02). Only CD44s expression and stage were correlated with overall survival in multivariate study. These results suggest that although E-cadherin, CD44s, CD56, and nuclear gamma-catenin immuno-expression seem to be useful prognostic markers for serous neoplasm of the ovary, CD44s expression and FIGO stage are independent prognostic factors.

Angiogenesis and antiangiogenic therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumor characterized by neovascularization, which plays an important role in the growth and progression of HCC. Angiogenesis provides a target for novel prognostic and therapeutic approaches to HCC. Assessment of microvessel density using immunohistochemical staining for specific endothelial cell markers such as CD34 has been shown to provide prognostic information independent of conventional pathological parameters in HCC patients. Recent studies have unveiled the important angiogenic factors involved in the regulation of angiogenesis in HCC, although the exact molecular pathways are far from clear. Current data suggest that vascular endothelial growth factor (VEGF) plays a critical role in angiogenesis of HCC. Tumor expression of VEGF has been shown to correlate with tumor invasiveness and prognosis in patients with HCC. VEGF is an important molecular target for antiangiogenic therapy. Studies in animal models have demonstrated the efficacy of antiangiogenic agents such as anti-VEGF antibody and antagonists of VEGF receptors in suppressing hepatocarcinogenesis and growth of HCC. Antiangiogenic therapy has already entered clinical trials in HCC patients and holds the promise of providing an effective novel treatment for HCC, which is of great clinical significance because there is no existing effective systemic therapy for HCC.

Angiogenesis in non-small cell lung cancer: The prognostic impact of neoangiogenesis and the cytokines VEGF and bFGF in tumours and blood

BACKGROUND

Due to a dismal prognosis of advanced lung cancer, novel screening tools and more effective treatments are clearly needed. Lately, an increasing number of tumour-released angiogenic cytokines which affect vessel formation, tumour growth, invasion, and metastasis have been identified. Vascular endothelial growth factors (VEGFs) and basic fibroblast growth factor (bFGF) are among the most important angiogenic factors. Based on available literature, we have explored the mechanisms of angiogenesis and its prognostic significance in non-small cell lung cancer, estimated by microvessel density (MVD) and the presence of VEGF and bFGF in the tumour and blood from NSCLC patients.

METHODS

Several comprehensive Pubmed searches for the period January 1993 to May 2005 were performed using strategic combinations of the terms non-small cell lung cancer, angiogenesis, vascular endothelial growth factor, basic fibroblast growth factor, tumour expression, microvessel density, circulating, and serum.

RESULTS

NSCLC neoangiogenesis, as measured by MVD, and tumour expression of VEGF are poor prognostic factors for survival (MVD, HR 1.8-2.0; VEGF, HR 1.5). bFGF tumour expression is also associated with poor survival and more aggressive disease. When evaluating the prognostic impact of elevated VEGF levels in blood, 10 of 16 studies (63%) indicated a negative prognostic impact. Of five studies on the prognostic value of circulating bFGF, three studies reported a negative prognostic impact, while one indicated bFGF as a good prognostic factor and one was inconclusive.

CONCLUSION

Angiogenic factors are poor prognostic indicators for tumour aggressiveness and survival in NSCLC. Assessments of circulating levels of VEGF and possibly bFGF may be valuable future tools for treatment planning and monitoring of treatment effect and relapse. First, however, these blood tests need to be standardised and validated in large-scale prospective clinical trials.

Phase I clinical and pharmacokinetic study of PTK/ZK, a multiple VEGF receptor inhibitor, in patients with liver metastases from solid tumours

The family of VEGF receptors are important mediators of angiogenesis, which is essential for tumour growth and metastasis. PTK/ZK is a multiple VEGF receptor inhibitor that blocks the activity of all known VEGF receptor tyrosine kinases. This phase I/II trial evaluated the safety, pharmacokinetics and efficacy of PTK/ZK in patients with liver metastases from solid tumours. Patients were administered oral PTK/ZK monotherapy once daily at doses of 300-1200 mg/day in 28-day cycles until unacceptable toxicity or tumour progression occurred. Twenty-seven patients were enrolled and treatment with PTK/ZK was generally well tolerated. The most frequently reported adverse events were fatigue, nausea, dizziness, and vomiting (mostly National Cancer Institute Common Toxicity Criteria grade 1 or 2). The area under the concentration-time curve (AUC) of PTK/ZK increased between 300 and 1000 mg/day with no further increase from 1000 to 1200 mg/day; the AUC decreased by 50% between day 1 and day 15. The DCE-MRI showed a statistically significant early reduction of tumour blood supply (measured as Ki) at day 2 at doses > or = 750 mg/day. Disease progression was significantly correlated with percent change from baseline Ki. Thirteen patients had stable disease for at least two cycles (56 days). Median overall survival was 11.8 months (95% CI = 6.6, 17.1 months). Long-term therapy with PTK/ZK demonstrated predictable pharmacokinetics, was safe and feasible in patients with metastatic disease, and showed promising clinical activity. The minimum biologically active dose was established at 750 mg/day whereas the recommended dose for phase III studies is 1200 mg/day.

Protein kinase C alpha expression in normal breast, ductal carcinoma in situ and invasive ductal carcinoma

The purpose of this study was to determine if Protein Kinase C alpha (PKC alpha) is altered in expression or localisation in normal breast, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC). We obtained 14 mixed cases of invasive ductal carcinoma (IDC) and DCIS, 36 pure DCIS cases and 25 cases of normal breast. The sections were stained immunohistochemically for PKC alpha expression. Staining was cytoplasmic. The results showed a progressive reduction in staining intensity from normal breast to invasive ductal carcinoma. The staining pattern was heterogeneous in the cytoplasm of DCIS and IDC, but homogeneous in the cytoplasm of normal breast ductal epithelium. Interestingly, mitotic cells and cells with aberrant nuclear morphology showed increased cytoplasmic staining in DCIS and IDC. PKC alpha activity is altered in dividing or abnormal cells, but overall expression is reduced in IDC. This raises the possibility of an alteration in the subcellular localisation of PKC alpha which may relate to changes in desmosomal adhesive state.

An immunohistochemical study of the expression of adhesion molecules in gallbladder lesions

We investigated the expression of 10 adhesion molecules (alpha-catenin, beta-catenin, gamma-catenin, CD44, CD44v6, ICAM-1, CD56, CEA, E-cadherin, and CD99) in 46 gallbladder carcinomas, 14 adenomas, 15 low-grade dysplasias, nine intestinal metaplasias, and 20 samples of normal gallbladder epithelium by immunohistochemistry. The expression of adhesion molecules was altered in gallbladder carcinomas and adenomas. In gallbladder carcinomas, increased expression of ICAM-1, CEA, and CD44v6 was observed, together with decreased expression of alpha/beta/gamma-catenin and CD99. In adenomas, aberrant expression of CD44v6 and CD56, as well as reduced expression of alpha/beta/gamma- and E-cadherins, was noted. Expression of alpha/beta/gamma-catenin was reduced in low-grade dysplasia, whereas there was no change in the expression of these adhesion molecules in metaplasia. Expression of ICAM-1, CD99, E-cadherin, and CD56 was correlated with clinical stage. In addition a correlation was noted between expression of ICAM-1 and E-cadherin and lymph node metastasis (p<0.05). These results suggest that altered expression of these adhesion molecules is involved in the progression and metastasis of gallbladder carcinomas.

The significance of angiogenesis in malignant pheochromocytomas

The purpose of this study was to investigate tumor angiogenesis in a series of benign and malignant pheochromocytomas and to determine whether there is a correlation between angiogenesis and the presence of distant metastases. In this study, the CD31 monoclonal antibody was selected to measure intratumoral microvessel density. Nineteen patients with malignant pheochromocytomas and nineteen patients with benign pheochromocytomas who underwent operation were studied. In order to quantify intratumoral microvessel density, the total number of pixels of CD31-positive reactivity was assessed and expressed as a percentage of the total tissue area in the analyzed field. Analysis of variance revealed a statistically significant correlation between malignancy and intratumoral microvessel density (p = 0.0009). Although there was a considerable variability in the intratumoral microvessel density from tumor to tumor within both the benign and the malignant group, a percentage of more than 28.5% anti-CD31 stained area was found only in malignant tumors. In conclusion, this study shows that the mean intratumoral microvessel density in malignant pheochromocytomas is increased approximately twofold as compared with benign tumors. However, the clinical significance of this prognostic marker is rather weak, because only 4 of the 19 malignant pheochromocytomas had microvessel density higher than this threshold of 28.5%.

Significance of microvascular density (MVD) in cervical cancer recurrence

The purpose of this retrospective study of 118 patients with squamous cell cervical cancer from January 1990 to December 1993 was to evaluate angiogenesis as predictive factor of recurrence in cervical cancer stages II-III treated with standard radiotherapy. Microvessel density (MVD) was evaluated and correlated with other prognostic factors. MVD was greater than 20 in 67.8% of patients with recurrence (P = 0.002) in comparison to 39% of patients without. Disease-free survival was shorter in stage IIA and MVD >20 (P = 0.0193) as well as for stage IIB (P < 0.05 ), but not for IIIB (P = 0.1613 ). Global survival was significantly shorter when MVD was >20 (P = 0.0316). For stage IIA and MVD >20 survival was shorter (P = 0.0008) for stage IIB (P < 0.05) but not for IIIB (P = 0.14). Patients younger than 40 years and MVD >20 had poorer disease-free interval and survival (P = 0.0029). MVD in patients with squamous cell cervical cancer stage II and age younger than 40 may play a role in predicting recurrence and survival.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Elevated serum endostatin is associated with poor outcome in patients with non-Hodgkin lymphoma

BACKGROUND

Endostatin is a cleaved fragment of collagen Type XVIII and has antiangiogenic activity. The clinical significance of circulating, soluble endostatin (S-endostatin) is not known.

METHODS

Pretreatment S-endostatin and serum vascular endothelial growth factor (S-VEGF) levels were measured in 143 patients with non-Hodgkin lymphoma (NHL) using competitive enzyme immunoassays and were compared with the levels from a control group (n = 24 participants).

RESULTS

S-endostatin levels varied widely from 4.5 ng/mL to 116 ng/mL (median, 29.6 ng/mL), and the median level was higher in patients with NHL compared with patients in the control group (16.4 ng/mL; P = 0.05). High S-endostatin levels were associated with advanced disease stage (P < 0.0001) and high serum VEGF levels at diagnosis (P = 0.017). The median 5-year survival rate for patients who had S-endostatin concentrations within the highest tertile (> 36.0 ng/mL) was only 34% compared with 57% in patients who had lower S-endostatin levels (P = 0.019). A high S-endostatin level also was associated with a poor outcome in patients with large cell diffuse and immunoblastic lymphoma, which was the largest subgroup within the series (n = 60 patients). Patients who had high pretreatment levels of both S-VEGF and S-endostatin had particularly poor outcomes. High S-endostatin levels had an independent, adverse influence on survival it was entered as a factor into a multivariate analysis together with the factors included in the International Prognostic Index (relative risk, 1.80; 95% confidence interval, 1.08-2.98; P = 0.0024).

CONCLUSIONS

High pretreatment levels of S-endostatin are associated with high serum VEGF levels and poor survival in patients with NHL. Prospective studies are warranted to establish the clinical value of longitudinal S-endostatin measurements.

Dynamic-enhanced MRI predicts metastatic potential of invasive ductal breast cancer

BACKGROUND

Dynamic magnetic resonance imaging (MRI) has improved the detection of breast malignancies. The method is based on estimating the velocity of contrast enhancement taking into account increased angiogenesis in tumor. Microvessel density correlates with breast carcinoma metastasis. Thus, we hypothesized that contrast enhancement on MRI correlates with metastasis in breast cancer patients. The present study attempts to clarify the quantitative assessment of dynamic data, and examines the correlation between MRI enhancement and breast carcinoma metastasis.

METHODS

The subjects consisted of 31 patients with invasive ductal breast cancer. Twenty patients were disease free for five years (group A), and eleven patients suffered from metastatic disease at distant sites concurrently or postoperatively (group B). Dynamic MRI was performed preoperatively using a 1.5T system in all cases. Using the dynamic data, the signal intensity (SI)ratio and SI index were determined and analyzed retrospectively taking into account the presence of distant metastases.

RESULTS

The values of the SI ratio were 2.2+/-0.7 in group A and 2.3+/-0.4 in group B, respectively, with no significant difference seen between the groups. The SI index value was significantly higher in group B (28.5+/-32.8) than in group A (10.3+/-5.5, p<0.05).

CONCLUSIONS

The current series suggests that the SI index could distinguish patients with high risk of distant metastasis from disease free patients, preoperatively. If a suitable borderline value were established, the quantitative dynamic parameter determined by MRI may be useful for predicting the prognosis of breast cancer patients.

Cell adhesion molecules and adhesion abnormalities in prostate cancer

Prostate cancer, the leading male cancer in Western countries, has accelerated in its incidence in the past decade. Patients with prostate cancer frequently have a poor prognosis as a result of local or distant spread of cancer. This review summarises some of the recent progress made in understanding the biology of cancer metastasis with a special emphasis on the role of cell adhesion molecules and adhesion abnormalities. The molecular and cellular function of cell adhesion molecules, their role in cancer and cancer progression, the clinical impact of these molecules, and therapeutic considerations are also discussed.

Serum levels of E-selectin, ICAM-1 and VCAM-1 in colorectal cancer patients: correlations with clinicopathological features, patient survival and tumour surgery

The serum concentrations of the cell adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were investigated in 63 patients with colorectal cancer and in 51 controls by an enzyme-linked immunosorbent assay (ELISA). Their relationship to clinicopathological variables and patient survival and changes in their levels after surgery were examined. Colorectal cancer patients showed significantly higher serum levels of E-selectin, ICAM-1 and VCAM-1 compared with healthy controls. There was a significant association between the serum levels of these molecules, disease stage and the presence of both lymph node and distant metastases. Both ICAM-1 and VCAM-1 levels correlated with serum E-selectin and carcinoembryonic antigen (CEA) levels. Serum levels of all three molecules decreased significantly after radical resection of the tumour. Elevated pre-operative E-selectin, ICAM-1 and VCAM-1 levels were significant prognostic factors, although not independent of stage, for patient survival. These findings suggest that serum concentrations of E-selectin, ICAM-1 and VCAM-1 may reflect tumour progression and metastasis. Since these markers are linked to CEA levels, it is uncertain whether their measurement will prove cost-effective in colorectal cancer management.

Clinical implications of circulating angiogenic factors in cancer patients

PURPOSE

Angiogenesis, a process fundamental to tumor growth, is regulated by angiogenic factors. This article reviews prognostic and other clinical implications of circulating angiogenic factors in cancer patients.

METHODS

A MEDLINE search of literature was performed using the names of various angiogenic factors as the key words. Studies pertaining to circulating angiogenic factors in cancer patients were reviewed. Pertinent literature regarding tumor expression of common angiogenic factors and their prognostic relevance in human cancers were also examined.

RESULTS

A substantial number of studies have demonstrated a strong association between elevated tumor expression of vascular endothelial growth factor (VEGF) and advanced disease or poor prognosis in various cancers. This supports the pivotal role of VEGF in regulating tumor angiogenesis. More recently, there is mounting evidence that the level of circulating VEGF in patients with different types of cancer may be predictive of tumor status and prognosis. Preliminary data also suggest that circulating VEGF may be useful in predicting and monitoring tumor response to anticancer therapies and in follow-up surveillance for tumor relapse. There are reports supporting the prognostic value of other circulating angiogenic factors such as basic fibroblast growth factor, platelet-derived endothelial cell growth factor, transforming growth factor-beta, and angiogenin, but their clinical significance is less conclusive because of limited data.

CONCLUSION

Circulating VEGF seems to be a reliable surrogate marker of angiogenic activity and tumor progression in cancer patients. Evaluation of circulating angiogenic factors is a promising novel approach of prognostication in cancer patients that has the advantages of being convenient and noninvasive, and it may provide new prognostic information that is not afforded by conventional clinicopathologic prognostic indicators.

Anti-metastatic gene therapy utilizing subcutaneous inoculation of EC-SOD gene transduced autologous fibroblast suppressed lung metastasis of Meth-A cells and 3LL cells in mice

We have previously reported that superoxide stimulates the motility of tumor cells and the administration of Cu-Zn superoxide dismutase (SOD) significantly suppresses metastasis. However, ideally, anti-metastatic therapy should be long-lasting, systemically effective and have low toxicity. The half-life of Cu-Zn SOD in plasma is so short that it cannot provide long-lasting effects. Therefore, in this study we have developed a gene therapy in a mouse model utilizing extracellular SOD (EC-SOD), which is the most prevalent SOD isoenzyme in extracellular fluids. We retrovirally transfected fibroblasts (syngeneic) with the EC-SOD gene and established EC-SOD-secreting fibroblasts. Inoculation of EC-SOD-secreting fibroblasts suppressed both artificial and spontaneous metastatic lung nodules in mouse metastasis models. These data indicate the feasibility of anti-metastatic gene therapy utilizing the EC-SOD gene.

Platelet-derived endothelial cell growth factor/thymidine phosphorylase concentrations differ in small cell and non-small cell lung cancer

OBJECTIVE

Platelet-derived endothelial cell growth factor (PD-ECGF)/thymidine phosphorylase (TP) has been implicated in cancer angiogenesis, which is critical for tumor growth and metastasis. We investigated the relationship between the tissue concentration of PD-ECGF/TP and the clinicopathologic status in human lung cancer.

METHODS

The concentrations of PD-ECGF/TP in the tumor extracts of 139 primary human lung carcinomas were measured by using a highly specific and sensitive enzyme-linked immunosorbent assay.

RESULTS

PD-ECGF/TP was detected in the extracts from 137 of 139 specimens at concentrations that ranged from 2.0 to 169.5 U/mg protein. PD-ECGF/TP concentrations in patients with adenocarcinoma (n = 73) and squamous cell carcinoma (n = 49) were (mean +/- SD) 30.7+/-22.9 U/mg protein (range, 7.6 to 169.5 U/mg protein) and 32.0+/-19.8 U/mg protein (range, 8.0 to 84.4 U/mg protein), respectively. No significant difference was found in the PD-ECGF/TP concentration between these two types of non-small cell lung cancer (NSCLC). However, a > 8-fold lower mean concentration of PD-ECGF/TP was found in tissue extracts from small cell lung cancer (SCLC) (n = 17; 3.65+/-2.01 U/mg protein, ranging from undetectable to 6.1 U/mg protein) than in those from adenocarcinomas (p = 0.00005) or squamous cell carcinomas (p < 0.00001).

CONCLUSIONS

The striking difference in PD-ECGF/TP concentrations between SCLC and NSCLC suggests that these two types of lung cancer use alternative pathways for angiogenesis. The present study suggests that inhibitors of PD-ECGF/TP, which have been recently developed and are under laboratory investigation to test their effectiveness as treatments for various types of cancer, may not be effective against SCLC.

The immunohistochemical expression of desmoplakin and its role in vivo in the progression and metastasis of breast cancer

Desmoplakin (DP) is a protein located at the inner plaque of desmosomes where it associates with the desmosomal cadherins to form a cell adhesion complex. Reduced expression of DP has been correlated with the progression of several cancers, but its role in in vivo breast cancer is yet to be established. The aim of this present paper was to determine the immunohistochemical (IHC) expression of DP in breast cancer specimens (n = 75) in comparison with ductal carcinoma in situ (DCIS) (n = 26), tumour associated normal (n = 29) and normal breast tissue (n = 7). DP expression was correlated with that of desmosomal cadherin, Desmoglein 2 (Dsg2) and other clinical and IHC prognostic markers. DP staining occurred at the sub-plasma membrane level. There was no significant correlation between the level of DP (as assessed by the H-score) and that of Dsg. Significantly stronger staining was demonstrated in normal breast tissue and well differentiated tumours compared with more moderately or poorly differentiated tumours (P = 0.04). A significant inverse correlation was seen between DP staining and tumour size (P = 0.01). In a limited series of 8 cases, primary tumours demonstrated significantly stronger staining than the matched metastatic lymph nodes (P = 0.046). Of all the IHC markers examined, only Ki-67 showed a significant inverse relationship with DP staining (P = 0.01). In summary, the data suggest that loss of DP may be of potential importance in progression of breast cancer in vivo from normal, DCIS, well differentiated through to poorly differentiated, large tumours. In addition, this loss may be associated with metastasis.

Enhanced inhibition of experimental metastasis by the combination chemotherapy of Cu-Zn SOD and adriamycin

We previously reported that reactive oxygen species (ROS) enhance tumor cell metastasis, and by administration of recombinant human superoxide dismutase (rh SOD), an enzyme which scavenges O2- successfully reduced lung metastasis of mouse MethA sarcoma and Lewis lung carcinoma. These observations suggested that rh SOD suppressed tumor cell invasion by eliminating O2- the primary source of ROS. However, for the clinical application of the drug as an anti metastatic agent, rh SOD needs to be administered in combination with other cytotoxic agents, since SOD by itself has no cytotoxic activity. In this paper, we investigated the effectiveness of the combination chemotherapy of rh SOD and adriamycin (ADR), an anti-cancer agent against the experimental metastasis of highly metastatic clone, MH-02, which was derived from murine Meth A sarcoma. The present metastasis experiment clearly indicates that the administration of rh SOD enhances the antimetastatic effect of ADR. On the other hand, we found that the inhibition rate of metastasis exhibited by the combination chemotherapy of rh SOD and a certain dose (5 mg/ml) of ADR was inferior to that of rh SOD. This apparent paradoxical phenomenon was presumably explained by our finding that tumor cells themselves augment their invasive capacity and platelet aggregation, both of which are causative factors for metastasis formation, by generation of O2- when they were treated with ADR. Nevertheless, the combination chemotherapy of SOD with anticancer drugs such as ADR can be a practical anti-metastasis strategy.

Significance of angiogenesis in cancer therapy

BACKGROUND

For most solid tumours, surgery remains the most effective primary treatment. Despite apparently curative resection, significant numbers of patients develop secondary disease due to growth of undetected micrometastases. The ability of a tumour to metastasize is related to the degree of angiogenesis it induces. In addition, micrometastases rely on new vessel formation to provide the nutrients necessary for growth. A better understanding of how tumours acquire their blood supply may lead to more effective adjuvant therapies and improve survival following surgery.

METHODS

A systematic review of the literature on angiogenesis between 1971 and 1997 was performed using the Medline database to ascertain current thinking on angiogenesis and its relevance in oncological surgery.

RESULTS

Angiogenesis is a physiological process subject to autocrine and paracrine regulation which has the potential to become abnormal and play a part in a number of pathological states, including cancer. Increased angiogenic stimuli in the perioperative period, associated with concomitant reduction in tumour-derived antiangiogenic factors following resection of a primary tumour, result in a permissive environment which allows micrometastases to grow.

CONCLUSION

Recognition of the role of angiogenesis in metastatic tumour growth represents a significant development in our understanding of tumour biology. The development of antiangiogenic agents offers new promise in the treatment of malignancy. Such agents may prevent or control the development and growth of primary and metastatic tumours.

Thymosin beta15 expression in tumor cell lines with varying metastatic potential

We previously isolated thymosin beta15 from highly metastatic Dunning rat prostatic carcinoma cells. Immunohistochemical study of human prostate cancer specimens revealed a general correlation between Gleason grade and thymosin beta15 expression, with high-grade (more malignant) tumors showing increased staining compared to low-grade tumors. To determine whether thymosin beta15 may be differentially expressed in cancer cells with different metastatic potential other than in the prostatic carcinoma cells, we examined thymosin beta15 mRNA levels in tumor cell lines from different species. We also examined thymosin beta15 protein levels in human breast cancer samples. Thymosin beta15 was upregulated in the highly metastatic mouse lung and human breast cancer cell lines in comparison to the nonmetastatic counterparts. Immunohistochemical staining showed the evidence of upregulation of thymosin beta15 in malignant human breast carcinomas as compared to benign breast tumors. The expression of thymosin beta15 was correlated with the metastatic potential of the mouse lung carcinoma and human breast carcinoma cells in addition to the prostatic carcinomas. Thymosin beta15 may be a useful marker to predict metastatic potential of certain human cancers.

Autotaxin, tumor motility-stimulating exophosphodiesterase

While nucleotides have a well-established role in intracellular metabolism, ATP and other nucleotides also have important extracellular roles in receptor-mediated signal transduction (34, 35). Extracellular or cell surface proteins capable of binding ATP and hydrolyzing phosphoester bonds of nucleotides are known to exist but their function has remained obscure. Our recent data point to a structure-function correlation between PDE activity and motility stimulation by ATX, indicating a biologically important functional role for the ecto/exophosdiesterases in the stimulation of cellular motility. Data from studies with PC-1 and gp130RB13-6 have suggested that cell surface PDE's may also play roles in cellular differentiation. Extracellular PDE activities, in combination with other nucleotidases, may result in ecto-nucleotidase cascades (36-38). These data suggest that ecto-/exo-enzymes may catalyze extracellular biochemical reactions that are important in the regulation of cell behavior.

Quantitative analysis of tryptase and chymase containing mast cells in benign and malignant breast lesions

The aim of our work was to study the number and distribution of tryptase- and chymase-containing mast cells in benign and malignant breast lesions. Tryptase positivity reflects the total number of mast cells, whereas chymase is not present in all mast cells. Active forms of tryptase and chymase were demonstrated enzymo-histochemically in 30 benign and 98 malignant fresh frozen breast lesions, which were graded and analysed morphometrically and statistically. The exclusive presence of tryptase and chymase in mast cells was confirmed in 5 cases by a sequential double-staining method. In benign lesions, the number of mast cells exhibiting tryptase activity was similar to that of chymase-active mast cells. Malignant tumours, however, had 2 to 3 times more tryptase-containing than chymase-containing mast cells, while the number of mast cells with tryptase activity was significantly higher (p < 0.02) than in benign lesions. In malignant lesions, tryptase-containing mast cells were concentrated at the tumour edge, i.e., the "invasion zone," whereas chymase-containing mast cells were not increased in this area.

The spectrum of 67-kD laminin receptor expression in breast carcinoma progression

Laminin is a glycoprotein of the basement membrane (BM), involved in a variety of normal and pathological cellular events including tumour invasion and metastasis. Cells bind laminin through different types of receptor. The 67-kD laminin receptor (67LR) is a cell-surface protein which binds laminin with high affinity. 67LR expression has been shown to increase in neoplastic cells, compared with normal tissues, and 67LR seems to play an important role during the first steps of neoplastic progression. In this study, 67LR expression was analysed during the morphological phases of breast cancer progression from normal tissue to invasive carcinoma. A total of 506 formalin-fixed, paraffin-embedded normal breast structures and lesions were stained by immunohistochemistry usign the MLuC5 monoclonal antibody, which is specific for 67LR. The results show that in normal breast and in any kind of breast lesion, myoepithelial and endothelial cells express 67LR. While 67LR is not seen in the epithelium of normal breast, cysts, adenosis, and benign tumours, it is expressed in the epithelial cells of several hyperplasias and carcinomas in situ, both ductal and lobular, as well as in all invasive carcinomas. The 67LR-positive cell subpopulation expands from hyperplastic lesions to invasive carcinoma, suggesting that 67LR could be related to the induction and progression of breast cancer.

Thymosin beta 15: a novel regulator of tumor cell motility upregulated in metastatic prostate cancer

The Dunning rat prostatic carcinoma is a model system where cell motility closely correlates with the metastatic phenotype. We have identified a novel gene, upregulated in the highly motile and metastatic Dunning cancer cell lines, that represents a new member of the thymosin-beta family, thymosin beta 15. Transfection of antisense thymosin beta 15 constructs into rat prostatic carcinoma cells demonstrates that this molecule positively regulates cell motility, a critical component of the metastatic pathway. Thymosin beta 15 levels are elevated in human prostate cancer and correlate positively with the Gleason tumor grade. Thymosin beta 15 may represent a potential new biochemical marker for human prostate cancer progression.

Inhibition of motility and invasion of human lung cancer cells by invasion inhibiting factor 2

The motility and invasion of cancer cells are basic requirements for the establishment of distant metastases. In this study, we examined the effect of invasion inhibiting factor 2 (IIF2), a motility/invasion regulatory agent, on the motility, invasion, growth and basement membrane attachment of human lung cancer cells. IIF2 significantly reduced cell dissociation, colony scattering and invasion induced by the motogenic factor, HGF/SF. Western and Northern analyses showed these cells to be positive for the HGF/SF receptor c-met. These effects were blocked by an anti-IIF2 antibody. IIF2 did not affect the growth and attachment of lung cancer cells to the basement membrane. It is concluded therefore that invasion inhibiting factor 2 is an inhibitor of human lung cancer cell motility and invasion in vitro and this may bear some importance in the construction of anti-metastatic therapies.

E-cadherin and its associated protein catenins, cancer invasion and metastasis

E-cadherin is a cell-cell adhesion molecule which is anchored to the cytoskeleton via catenins. There is increasing evidence which suggests that E-cadherin also acts as a suppressor of tumour invasion and metastasis. Both in vitro and in vivo studies have revealed that expression of E-cadherin correlates inversely with the motile and invasive behaviour of a tumour cell; it also correlates inversely with metastasis in patients with cancer. The function of E-cadherin is highly dependent on the functional activity of catenins. This review summarizes progress, from both basic and clinical research, in our understanding of the roles of E-cadherin and catenins, and discusses the clinical relevance of the discoveries.