Hepatocyte growth factor is an invasion/migration factor of rat urothelial carcinoma cells in vitro

c-Met: A Promising Therapeutic Target in Bladder Cancer

Mesenchymal-epithelial transition factor (c-Met) belongs to the tyrosine kinase receptor family and is overexpressed in various human cancers. Its ligand is hepatocyte growth factor (HGF), and the HGF/c-Met signaling pathway is involved in a wide range of cellular processes, including cell proliferation, migration, and metastasis. Emerging studies have indicated that c-Met expression is strongly associated with bladder cancer (BCa) development and prognosis. Therefore, c-Met is a potential therapeutic target for BCa treatment. Recently, the aberrant expression of noncoding RNAs was found to play a significant role in tumour progression. There is a close connection between c-Met and noncoding RNA. Herein, we summarized the biological function and prognostic value of c-Met in BCa, as well as its potential role as a drug target. The relation of c-Met and ncRNA was also described in the paper.

Single-cell RNAseq and longitudinal proteomic analysis of a novel semi-spontaneous urothelial cancer model reveals tumor cell heterogeneity and pretumoral urine protein alterations

Bladder cancer, one of the most prevalent malignancies worldwide, remains hard to classify due to a staggering molecular complexity. Despite a plethora of diagnostic tools and therapies, it is hard to outline the key steps leading up to the transition from high-risk non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC). Carcinogen-induced murine models can recapitulate urothelial carcinogenesis and natural anti-tumor immunity. Herein, we have developed and profiled a novel model of progressive NMIBC based on 10 weeks of OH-BBN exposure in hepatocyte growth factor/cyclin dependent kinase 4 (R24C) (Hgf-Cdk4R24C) mice. The profiling of the model was performed by histology grading, single cell transcriptomic and proteomic analysis, while the derivation of a tumorigenic cell line was validated and used to assess in vivo anti-tumor effects in response to immunotherapy. Established NMIBC was present in females at 10 weeks post OH-BBN exposure while neoplasia was not as advanced in male mice, however all mice progressed to MIBC. Single cell RNA sequencing analysis revealed an intratumoral heterogeneity also described in the human disease trajectory. Moreover, although immune activation biomarkers were elevated in urine during carcinogen exposure, anti-programmed cell death protein 1 (anti-PD1) monotherapy did not prevent tumor progression. Furthermore, anti-PD1 immunotherapy did not control the growth of subcutaneous tumors formed by the newly derived urothelial cancer cell line. However, treatment with CpG-oligodeoxynucleotides (ODN) significantly decreased tumor volume, but only in females. In conclusion, the molecular map of this novel preclinical model of bladder cancer provides an opportunity to further investigate pharmacological therapies ahead with regards to both targeted drugs and immunotherapies to improve the strategies of how we should tackle the heterogeneous tumor microenvironment in urothelial bladder cancer to improve responses rates in the clinic.

Nanodrug Delivery Systems Modulate Tumor Vessels to Increase the Enhanced Permeability and Retention Effect

The use of nanomedicine for antitumor therapy has been extensively investigated for a long time. Enhanced permeability and retention (EPR) effect-mediated drug delivery is currently regarded as an effective way to bring drugs to tumors, especially macromolecular drugs and drug-loaded pharmaceutical nanocarriers. However, a disordered vessel network, and occluded or embolized tumor blood vessels seriously limit the EPR effect. To augment the EPR effect and improve curative effects, in this review, we focused on the perspective of tumor blood vessels, and analyzed the relationship among abnormal angiogenesis, abnormal vascular structure, irregular blood flow, extensive permeability of tumor vessels, and the EPR effect. In this commentary, nanoparticles including liposomes, micelles, and polymers extravasate through the tumor vasculature, which are based on modulating tumor vessels, to increase the EPR effect, thereby increasing their therapeutic effect.

Dysregulation of Type II Transmembrane Serine Proteases and Ligand-Dependent Activation of MET in Urological Cancers

Unlike in normal epithelium, dysregulated overactivation of various proteases have been reported in cancers. Degradation of pericancerous extracellular matrix leading to cancer cell invasion by matrix metalloproteases is well known evidence. On the other hand, several cell-surface proteases, including type II transmembrane serine proteases (TTSPs), also induce progression through activation of growth factors, protease activating receptors and other proteases. Hepatocyte growth factor (HGF) known as a multifunctional growth factor that upregulates cancer cell motility, invasiveness, proliferative, and anti-apoptotic activities through phosphorylation of MET (a specific receptor of HGF). HGF secreted as inactive zymogen (pro-HGF) from cancer associated stromal fibroblasts, and the proteolytic activation by several TTSPs including matriptase and hepsin is required. The activation is strictly regulated by HGF activator inhibitors (HAIs) in physiological condition. However, downregulation is frequently observed in cancers. Indeed, overactivation of MET by upregulation of matriptase and hepsin accompanied by the downregulation of HAIs in urological cancers (prostate cancer, renal cell carcinoma, and bladder cancer) are also reported, a phenomenon observed in cancer cells with malignant phenotype, and correlated with poor prognosis. In this review, we summarized current reports focusing on TTSPs, HAIs, and MET signaling axis in urological cancers.

c-Met expression and activity in urogenital cancers - novel aspects of signal transduction and medical implications

C-Met is a receptor tyrosine kinase with multiple functions throughout embryonic development, organogenesis and wound healing and is expressed in various epithelia. The ligand of c-Met is Hepatocyte Growth Factor (HGF) which is secreted among others by mesenchymal stroma/stem (MSC) cells.

Physiological c-Met functions are centred around processes that underly cellular motility and invasive growth. Aberrant c-Met expression and activity is observed in numerous cancers and makes major contributions to cell malignancy. Importantly, HGF/c-Met signaling is crucial in the context of communication between cancer cells and the the tumor stroma.

Here, we review recent findings on roles of dysregulated c-Met in urogenital tumors such as cancers of the urinary bladder, prostate, and ovary. We put emphasis on novel aspects of cancer-associated c-Met expression regulation on both, HGF-dependent and HGF-independent non-canonical mechanisms. Moreover, this review focusses on c-Met-triggered signalling with potential relevance for urogenital oncogenesis, and on strategies to specifically inhibit c-Met activity.

Met in urological cancers

Met is a tyrosine kinase receptor that is considered to be a proto-oncogene. The hepatocyte growth factor (HGF)-Met signaling system plays an important role in tumor growth, invasion, and metastasis in many types of malignancies. Furthermore, Met expression has been reported to be a useful predictive biomarker for disease progression and patient survival in these malignancies. Many studies have focused on the clinical significance and prognostic role of Met in urological cancers, including prostate cancer (PCa), renal cell carcinoma (RCC), and urothelial cancer. Several preclinical studies and clinical trials are in progress. In this review, the current understanding of the pathological role of Met in cancer cell lines, its clinical significance in cancer tissues, and its predictive value in patients with urological cancers are summarized. In particular, Met-related malignant behavior in castration-resistant PCa and the different pathological roles Met plays in papillary RCC and other histological types of RCC are the subjects of focus. In addition, the pathological significance of phosphorylated Met in these cancers is shown. In recent years, Met has been recognized as a potential therapeutic target in various types of cancer; therapeutic strategies used by Met-targeted agents in urological cancers are summarized in this review.

Characterization of HGF/Met Signaling in Cell Lines Derived From Urothelial Carcinoma of the Bladder

There is mounting evidence of oncogenic hepatocyte growth factor (HGF)/Met signaling in urothelial carcinoma (UC) of the bladder. The effects of three kinase inhibitors, cabozantinib, crizotinib and EMD1214063, on HGF-driven signaling and cell growth, invasion and tumorigenicity were analyzed in cultured UC cell lines. SW780 xenograft growth in SCID and human HGF knock-in SCID (hHGF/SCID) mice treated with cabozantinib or vehicle, as well as tumor levels of Met and pMet, were also determined. Met content was robust in most UC-derived cell lines. Basal pMet content and effector activation state in quiescent cells were low, but significantly enhanced by added HGF, as were cell invasion, proliferation and anchorage independent growth. These HGF-driven effects were reversed by Met inhibitor treatment. Tumor xenograft growth was significantly higher in hHGF/SCID mice vs. SCID mice and significantly inhibited by cabozantinib, as was tumor phospho-Met content. These studies indicate the prevalence and functionality of the HGF/Met signaling pathway in UC cells, suggest that paracrine HGF may contribute to UC tumor growth and progression, and that support further preclinical investigation of Met inhibitors for the treatment of UC is warranted.

Preliminary evaluation of urinary soluble Met as a biomarker for urothelial carcinoma of the bladder

BACKGROUND

Among genitourinary malignancies, bladder cancer (BCa) ranks second in both prevalence and cause of death. Biomarkers of BCa for diagnosis, prognosis and disease surveillance could potentially help prevent progression, improve survival rates and reduce health care costs. Among several oncogenic signaling pathways implicated in BCa progression is that of hepatocyte growth factor (HGF) and its cell surface receptor, Met, now targeted by 25 experimental anti-cancer agents in human clinical trials. The involvement of this pathway in several cancers is likely to preclude the use of urinary soluble Met (sMet), which has been correlated with malignancy, for initial BCa screening. However, its potential utility as an aid to disease surveillance and to identify patients likely to benefit from HGF/Met-targeted therapies provide the rationale for this preliminary retrospective study comparing sMet levels between benign conditions and primary BCa, and in BCa cases, between different disease stages.

METHODS

Normally voided urine samples were collected from patients with BCa (Total: 183; pTa: 55, pTis: 62, pT1: 24, pT2: 42) and without BCa (Total: 83) on tissue-procurement protocols at three institutions and sMet was measured and normalized to urinary creatinine. Normalized sMet values grouped by pathologic stage were compared using non-parametric tests for correlation and significant difference. ROC analyses were used to derive classification models for patients with or without BCa and patients with or without muscle-invasive BCa (MIBCa or NMIBCa).

RESULTS

Urinary sMet levels accurately distinguished patients with BCa from those without (p<0.0001, area under the curve (AUC): 0.7008) with limited sensitivity (61%) and moderate specificity (76%), and patients with MIBCa (n=42) from those with NMIBCa (n=141; p<0.0001, AUC: 0.8002) with moderate sensitivity and specificity (76% and 77%, respectively) and low false negative rate (8%).

CONCLUSIONS

Urinary sMet levels distinguish patients with BCa from those without, and patients with or without MIBCa, suggesting the potential utility of urinary sMet as a BCa biomarker for surveillance following initial treatment. Further studies are warranted to determine its potential value for prognosis in advanced disease, predicting treatment response, or identifying patients likely to benefit from Met-targeted therapies.

Bladder carcinoma: understanding advanced and metastatic disease with potential molecular therapeutic targets

This article is an expert review of bladder cancer genetics focusing on genetic changes and their significance in the pathogenesis and progression of bladder transitional cell carcinoma, in particular, muscle-invasive disease. Alongside the relevant genetic markers and their products, new therapeutic targets and agents that are being developed are presented.

Targeting tumor micro-environment for design and development of novel anti-angiogenic agents arresting tumor growth

Angiogenesis: a process of generation of new blood vessels has been proved to be necessary for sustained tumor growth and cancer progression. Inhibiting angiogenesis pathway has long been remained a significant hope for the development of novel, effective and target orientated antitumor agents arresting the tumor proliferation and metastasis. The process of neoangiogenesis as a biological process is regulated by several pro- and anti-angiogenic factors, especially vascular endothelial growth factor, fibroblast growth factor, epidermal growth factor, hypoxia inducible factor 1 and transforming growth factor. Every endothelial cell destined for vessel formation is equipped with receptors for these angiogenic peptides. Moreover, numerous other angiogenic cytokines such as platelet derived growth factor (PGDF), placenta growth factor (PGF), nerve growth factor (NGF), stem-cell factor (SCF), and interleukins-2, 4, 6 etc. These molecular players performs critical role in regulating the angiogenic switch. Couple of decade's research in molecular aspects of tumor biology has unraveled numerous structural and functional mysteries of these angiogenic peptides. In present article, a detailed update on the functional and structural peculiarities of the various angiogenic peptides is described focusing on structural opportunities made available that has potential to be used to modulate function of these angiogenic peptides in developing therapeutic agents targeting neoplastic angiogenesis. The data may be useful in the mainstream of developing novel anticancer agents targeting tumor angiogenesis. We also discuss major therapeutic agents that are currently used in angiogenesis associated therapies as well as those are subject of active research or are in clinical trials.

Comprehensive analysis of receptor tyrosine kinase activation in human melanomas reveals autocrine signaling through IGF-1R

Melanomas depend on autocrine signals for proliferation and survival; however, no systematic screen of known receptor tyrosine kinases (RTKs) has been performed to identify which autocrine signaling pathways are activated in melanoma. Here, we performed a comprehensive analysis of 42 RTKs in six individual human melanoma tumor specimens as well as 17 melanoma cell lines, some of which were derived from the tumor specimens. We identified five RTKs that were active in almost every one of the melanoma tissue specimens and cell lines, including two previously unreported receptors, insulin-like growth factor receptor 1 (IGF-1R) and macrophage-stimulating protein receptor (MSPR), in addition to three receptors (vascular endothelial growth factor receptor, fibroblast growth factor receptor, and hepatocyte growth factor receptor) known to be autocrine activated in melanoma. We show, by quantitative real time PCR, that all melanoma cell lines expressed genes for the RTK ligands such as HGF, IGF-1, and MSP. Addition of antibodies to either IGF-1 or HGF, but not to MSP, to the culture medium blocked melanoma cell proliferation, and even caused net loss of melanoma cells. Antibody addition deactivated IGF-1R and hepatocyte growth factor receptors, as well as mitogen-activated protein kinase signaling. Thus, IGF-1 is a new growth factor for autocrine driven proliferation of human melanoma in vitro. Our results suggest that IGF-1-IGF-1R autocrine pathway in melanoma is a possible target for therapy in human melanomas.

Pathobiology and chemoprevention of bladder cancer

Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.

Co-expression of hepatocyte growth factor and c-Met predicts peritoneal dissemination established by autocrine hepatocyte growth factor/c-Met signaling in gastric cancer

Epithelial-mesenchymal transition (EMT) promotes and facilitates migration and invasion of epithelial tumor cells. EMT is induced by factors such as hepatocyte growth factor (HGF). This study aimed to establish whether the HGF/c-Met pathway is associated with gastric cancer metastasis; especially peritoneal dissemination. HGF and c-Met expression and EMT-related molecules were evaluated using real-time PCR and immunohistochemistry. The role of the HGF/c-Met pathway in EMT and anoikis was determined, and kinase inhibitor SU11274 was tested for its ability to block HGF-induced biological effects. In HGF(-) /c-Met(+) gastric cancer cells, recombinant HGF promoted an EMT phenotype that was characterized by morphology, impaired E-cadherin and induction of vimentin. HGF promoted cell growth, invasiveness and migration and inhibition of anoikis. SU11274 blocked HGF-induced EMT and biological effects in vitro. In HGF(+) /c-Met(+) gastric cancer cells, HGF did not affect the biological outcome of EMT and anoikis, but SU11274 exerted the same inhibitory effects as in HGF(-) /c-Met(+) cells. In vivo, HGF(+) /c-Met(+) gastric cancer cells only established peritoneal dissemination and SU11274 inhibited tumor growth. Clinically, HGF expression was significantly correlated with c-Met expression in gastric cancer. Increased HGF and c-Met had a significant association with poor prognosis and predicted peritoneal dissemination. We demonstrated that the HGF/c-Met pathway induces EMT and inhibition of anoikis in gastric cancer cells. Co-expression of HGF and c-Met has the potential to promote peritoneal dissemination in gastric cancer. Blockade of the autocrine HGF/c-Met pathway could be clinically useful for the treatment of peritoneal dissemination in gastric cancer.

Molecular profiling of angiogenesis in hypericin mediated photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) involves the administration of a tumor-localizing photosensitizing drug, which is activated by light of specific wavelength in the presence of molecular oxygen thus generating reactive oxygen species that is toxic to the tumor cells. PDT selectively destroys photosensitized tissue leading to various cellular and molecular responses. The present study was designed to examine the angiogenic responses at short (0.5 h) and long (6 h) drug light interval (DLI) hypericin-PDT (HY-PDT) treatment at 24 h and 30 days post treatment in a human bladder carcinoma xenograft model. As short DLI targets tumor vasculature and longer DLI induces greater cellular damage, we hypothesized a differential effect of these treatments on the expression of angiogenic factors.

RESULTS

Immunohistochemistry (IHC) results showed minimal CD31 stained endothelium at 24 h post short DLI PDT indicating extensive vascular damage. Angiogenic proteins such as vascular endothelial growth factor (VEGF), tumor necrosis growth factor-alpha (TNF-alpha), interferon-alpha (IFN-alpha) and basic fibroblast growth factor (bFGF) were expressed to a greater extent in cellular targeting long DLI PDT compared to vascular mediated short DLI PDT. Gene expression profiling for angiogenesis pathway demonstrated downregulation of adhesion molecules - cadherin 5, collagen alpha 1 and 3 at 24 h post treatment. Hepatocyte growth factor (HGF) and Ephrin-A3 (EFNA3) were upregulated in all treatment groups suggesting a possible activation of c-Met and Ephrin-Eph signaling pathways.

CONCLUSION

In conclusion, long DLI HY-PDT induces upregulation of angiogenic proteins. Differential expression of genes involved in the angiogenesis pathway was observed in the various groups treated with HY-PDT.

Liver regeneration and tumor stimulation--a review of cytokine and angiogenic factors

Liver resection for metastatic (colorectal carcinoma) tumors is often followed by a significant incidence of tumor recurrence. Cellular and molecular changes resulting from hepatectomy and the subsequent liver regeneration process may influence the kinetics of tumor growth and contribute to recurrence. Clinical and experimental evidence suggests that factors involved in liver regeneration may also stimulate the growth of occult tumors and the reactivation of dormant micrometastases. An understanding of the underlying changes may enable alternative strategies to minimize tumor recurrence and improve patient survival after hepatectomy.

MET expression in sporadic renal cell carcinomas

Although germline mutations of met proto-oncogene on human chromosome 7q31-34 have been known as useful molecular markers of hereditary papillary renal cell carcinoma (RCC), the expression of MET, a product of met proto-oncogene, has not been fully studied in sporadic RCC, along with its clinical significance. We investigated the expression of MET by immunohistochemistry in 182 cases of renal neoplasm encompassing 145 RCC, 25 urothelial carcinomas of renal pelvis, and 12 oncocytomas. MET was diffusely and strongly expressed in 90% of papillary RCC, all collecting duct carcinomas, and 92% of urothelial carcinomas of renal pelvis. On the contrary, clear cell RCC, chromophobe RCC, and oncocytomas were negative or focally positive for MET expression. In clear cell RCC, MET expression was positively correlated with high nuclear grade, presence of infiltrative growth, tumoral necrosis, papillary architecture, sarcomatoid component, tumoral involvement of the renal pelvis or ureter, involvement of the calyx, and lymphatic invasion. In conclusion, diffuse and strong expression of MET in papillary RCC and collecting duct carcinoma might be helpful in discriminating from the other subtypes of RCC with tubular or papillary growth. In case of MET expression observed in clear cell RCC, it might correlate with those clinicopathological parameters implying aggressive behavior.

Genetic alterations in urothelial bladder carcinoma: an updated review

New oncogenes and tumor suppressor genes that play an important role in the pathogenesis of urothelial bladder carcinoma have been discovered. The objectives of this review were to summarize the most important oncogenes and tumor suppressor genes involved in urothelial carcinoma and to address their role in pathogenesis, their prognostic value, and their potential use as therapeutic targets. The collected data led the authors to propose a common pathway in which the fibroblastic growth factor receptor 3 (FGFR3) mutation seems to be the earliest genetic abnormality responsible for the transformation from normal tissue to atypia and dysplasia. Three different progression pathways were proposed: The first operative pathway is from dysplasia to superficial papillary pathologic Ta (pTa) tumors to pT1 tumors and, ultimately, to pT2 tumors with FGFR3 and tuberous sclerosis complex 1 (TSC1) the responsible genes. The second major operative pathway is from dysplasia, to carcinoma in situ, and to solid pT1 and pT2 tumors. The third pathway of progression is from dysplasia to papillary T1 and pT2 tumors. The genes involved in the last 2 pathways are the p53, serine threonine protein kinase 15 (STK15), triple-function domain (TRIO), fragile histidine triad (FHIT), p63 genes; and alterations of 20q and 5p, alterations of adhesions, angiogenesis, and matrix-remodeling gene products also are involved. Finally, murine leukemia viral oncogene homologue 1 (RAF1) and CD9 are involved in the progression from papillary pT1 tumors to pT2 tumors.

Effects of hepatocyte growth factor/scatter factor on the invasion of colorectal cancer cells in vitro

AIM: Hepatocyte growth factor (HGF) is a multifunctional growth factor which has pleiotrophic biological effects on epithelial cells, such as proliferation, motogenesis, invas-iveness and morphogenesis. There are few reports about the role of HGF played in the colorectal cancer invasion. In the present study, we tried to investigate the possible mechanism of HGF involved in the invasion of colorectal cancer cells in vitro.

METHODS: Matrigel migration assay was used to analyze the migrational ability of Caco-2 and Colo320 in vitro. We detected the mRNA expressive levels of MMP-2, MMP-9 and their natural inhibitors TIMP-1, TIMP-2 in Caco-2 cells by reverse-transcription polymerase chain reaction (PCR) technique.

RESULTS: After 48 h incubation, there were notable differences when we compared the migrational numbers of Caco-2 cells in the group of HGF and PD98059 (the inhibitor of p42/p44MAPK) with the control (104.40 ± 4.77 vs 126.80 ± 5.40, t = 7.17, P = 0.002 < 0.01; 104.40 ± 4.77 vs 82.80 ± 4.15, t = 7.96, P = 0.001 < 0.01). The deviation between the HGF and PD98059 was significant (P < 0.01). Compared with controls, MMP-2 and MMP-9 mRNA expres-sions were up-regulated by HGF (0.997 ± 0.011 vs 1.207 ± 0.003, t = 35.002,P = 0.001 < 0.01; 0.387 ± 0.128 vs 0.971 ± 0.147, t = 106.036, P = 0.0000 < 0.01, respectively); compared with controls, TIMP-1, TIMP-2 mRNA expressions were increased by PD98059 (1.344 ± 0.007 vs 1.905 ± 0.049, t = 17.541, P = 0.003 < 0.01; 1.286 ± 0.020 vs 1.887 ± 0.022, t = 24.623, P = 0.002 < 0.01, respectively).

CONCLUSION: HGF promoted Caco-2 migration mainly by p42/p44MAPK pathway; HGF/SF stimulated the expression of MMP-2, MMP-9 in Caco-2 and enabled tumoral cells to damage the ECM and reach the distant organ and develop metastasis; HGF played the function of promoted-invasion and promoted-metastasis, in which cellular selection was possible.

Overexpression of the c-Met/HGF receptor and its prognostic significance in uterine cervix carcinomas

OBJECTIVE

The purpose of this study is to evaluate the significance of the c-Met/hepatocyte growth factor receptor expression in invasive cervical carcinoma.

METHODS

Ninety-Four patients with FIGO stage 1B disease, treated primarily with surgery, were studied immunohistochemically. Of the cases, 67 were squamous carcinoma and 27 were nonsquamous (10 were adenocarcinoma, 15 were adenosquamous carcinoma, and 2 were indifferentiated carcinoma). Immunohistochemically stained c-Met slides of primary malignancies were evaluated blindly of clinical outcome and other histopathological factors.

RESULTS

Overexpression of c-Met was found in 56 of 94 specimens. Primary tumors which show recurrences were found to be c-Met overexpressors. Univariate survival analysis (Kaplan-Meier) showed that c-Met overexpression is significantly correlated with disease-free survival. Moreover the diameter of the primary tumor, deep cervical stromal invasion, presence of metastatic lymph node, number of metastatic lymph nodes and c-Met overexpression were significantly correlated with overall 5-year survival. Furthermore multivariant analysis with Cox regression showed that the presence of metastatic lymph node and immunopositivity for c-Met are significantly correlated with overall survival, while c-Met overexpression was found to be an independent variable for disease-free survival.

CONCLUSION

These results reveal that c-Met oncogene overexpression is an important parameter for disease progression, recurrence, and survival in early-stage invasive uterine cervix carcinomas.

Angiogenesis in bladder cancer--prognostic marker and target for future therapy

Angiogenesis is the process by which tumours induce a blood supply, crucial for growth and metastasis. Evidence for its role in bladder carcinogenesis, its usefulness as a marker of patient prognosis, and potential anti-angiogenic therapies for future development are discussed in this chapter.

Expression and localization of HGF and met in Wilms' tumours

A number of growth factors and cognate receptors that contribute to normal kidney development have been shown to play roles in the pathogenesis of Wilms' tumours. Expression of both hepatocyte growth factor (HGF) and its tyrosine kinase receptor met has been demonstrated in normal tissues and their neoplastic counterparts, implicating these factors in normal development and tumour progression. HGF and met expression has not been studied in Wilms' tumour. Since HGF and met function in a paracrine fashion by regulating tubulogenesis in normal kidney development, they could be involved in the pathogenesis of Wilms' tumour, in which tubular formation is dysplastic. In the present study, a series of ten homotypic (consisting of blastemal, epithelial, and stromal elements) and ten heterotypic (consisting of triphasic histology and a muscle component) Wilms' tumour cases were examined for expression of HGF and met, using in situ hybridization, immunohistochemistry, and western blot analysis. Relatively high met message and protein expression, compared with normal kidney, were evident in homotypic and heterotypic tumour blastemal, epithelial, and rhabdomyoblastic cells and a 145 kD met polypeptide was found in all tumours, with a few cases also expressing the 170 kD precursor form. No apparent alterations of the met receptor were observed. Similarly, HGF protein was also abundantly expressed in blastemal, epithelial, and rhabdomyoblastic cells of the homotypic and heterotypic Wilms' tumours and a 69 kD HGF polypeptide was demonstrated by western blot analysis. Immunohistochemistry for the Ki-67 proliferation marker indicated that the pattern of Ki-67 expression correlated with the HGF and met pattern of expression in both homotypic and heterotypic tumours. These results reveal, for the first time, significant co-expression of met/HGF in Wilms' tumours, with a correspondingly high proliferative index in the same cell groups.

Downregulation of E-cadherin and Desmoglein 1 by autocrine hepatocyte growth factor during melanoma development

During melanoma development, transformed cells evade keratinocyte-mediated control by downregulating cell adhesion molecules. This study investigated the regulation of cell adhesion by hepatocyte growth factor (HGF) in melanoma. Melanocytes and two melanoma lines, WM164 and WM35, expressed normal level E-cadherin and Desmoglein 1, whereas most melanomas (18 out of 20) expressed no E-cadherin and significantly reduced Desmoglein 1. Overexpression of dominant negative E-cadherin and Desmoglein in melanocytes demonstrated that both molecules contribute to adhesion between melanocytes and keratinocytes. In contrast to melanocytes, most melanomas expressed HGF. All melanocytic cells expressed the HGF receptor c-Met, and autocrine HGF caused constitutive activation of c-Met, MAPK and PI3K. When autocrine activation was induced with HGF-expressing adenovirus, E-cadherin and Desmoglein 1 were decreased in melanocytes, WM164 and WM35. MAPK inhibitor PD98059 and PI3K inhibitor wortmannin partially blocked the downregulation, suggesting that both pathways are involved in this process. c-Met was coimmunoprecipitated with E-cadherin, Desmoglein 1 and Plakoglobin, suggesting that they form a complex (es) that acts to regulate intercellular adhesion. Together, the results indicate that autocrine HGF decouples melanomas from keratinocytes by downregulating E-cadherin and Desmoglein 1, therefore frees melanoma cells from the control by keratinocytes and allows dissemination of the tumor mass.

Enhanced IkappaB kinase activity is responsible for the augmented activity of NF-kappaB in human head and neck carcinoma cells

The nuclear transcription factor kappaB (NF-kappaB) plays an important role in the development and progression of cancers. However, the mechanism by which cancer cells in the head and neck region acquire high NF-kappaB activity has not yet been clarified. In this study, we examined the NF-kappaB binding activity and the expression of the signal-transduction-related proteins of NF-kappaB in head and neck carcinoma cell lines. These cancer cells showed significantly higher NF-kappaB binding activity than normal oral epithelial and salivary gland cells. We also demonstrated the increased phosphorylation and degradation of IkappaB-alpha protein in cancer cells. Thus, enhanced NF-kappaB activity in cancer cells is attributable to the rapid phosphorylation and degradation of IkappaB-alpha protein. To further elucidate the mechanism involved in this phenomenon, we analyzed both the expression levels of upstream kinases (IkappaB kinase- (IKK-) alpha, IKK-beta, IKK-gamma, and NF-kappaB-inducing kinase (NIK)) and the IKK activity in cells. Although there was no significant difference in the expression levels of NIK, IKK-beta, or IKK-gamma in cancer cell lines compared to those in normal cells, increased expression of IKK-alpha protein was observed in cancer cells. In addition, IKK activity was significantly augmented in cancer cells as compared to normal cells. Thus, our results suggest that enhanced NF-kappaB activity in head and neck cancer cells may be due to the augmentation of IKK activity.

Independent prognostic value of serum hepatocyte growth factor in bladder cancer

PURPOSE

We retrospectively investigated whether the level of serum hepatocyte growth factor could predict the prognosis and extent of transitional-cell carcinoma of the urinary bladder.

PATIENTS AND METHODS

Serum samples were collected from 113 patients with bladder cancer and from 200 healthy controls. Of the 113 patients, 59 had superficial bladder cancer and 54 had muscle-invasive cancer. Thirteen bladder cancer tissues (eight superficial and five muscle-invasive) were also collected. The levels of hepatocyte growth factor in the serum and tissues of these individuals were measured by enzyme-linked immunoadsorbent assay using hepatocyte growth factor antibodies.

RESULTS

The levels of hepatocyte growth factor in the serum and tissues of patients with muscle-invasive cancer were significantly higher than those of patients with superficial bladder cancer (P <.0001 and P =.0054, respectively). The degree of elevation above the normal level of serum hepatocyte growth factor of the former (61.1%) was significantly higher than that of the latter (8.4%; P <.0001). The elevation was highest in patients with visceral metastasis (93.3%). Among patients with superficial bladder cancer, the overall survival rate of those with low levels of serum hepatocyte growth factor was significantly greater than that of those with high levels (P =.005). Among patients with minimally invasive bladder cancer, the disease-free and overall survival rates of those with high levels of serum hepatocyte growth factor were significantly lower than the same rates of those with low levels (P <.001 and P =.0028, respectively).

CONCLUSION

Our study suggests that the level of hepatocyte growth factor in serum could be a predictor of patient survival and extent of bladder cancer.

Mechanism of regulation of HGF/SF gene expression in fibroblasts by TGF-beta1

The effect of transforming growth factor beta 1 (TGF-beta1) on levels of hepatocyte growth factor/scatter factor (HGF/SF) gene transcripts was investigated in the human lung embryonic fibroblast cell line, MRC-5. TGF-beta1 markedly reduced the expression of the 6. 0-kb and 3.0-kb HGF/SF mRNA, which encode full-length HGF/SF, but it had little effect on the expression of the alternatively spliced 1. 5-kb mRNA, which encodes NK2, a competitive HGF/SF antagonist. Using actinomycin D to block RNA synthesis, it was observed that TGF-beta1 had little effect on the stability of the 1.5-kb NK2 mRNA but increased the rate of degradation of the 6.0- and 3.0-kb HGF/SF mRNA transcripts by a mechanism that was dependent on new protein synthesis. TGF-beta1 minimally increased rather than reduced HGF/SF promoter activity in cells transiently transfected with chloramphenicol acetyltransferase (CAT) reporter genes driven by HGF/SF gene 5'-flanking sequences. In MRC-5 cells, TGF-beta1 modulates HGF/SF gene transcripts at the posttranscriptional level in order to favour expression of the 1.5-kb mRNA that encodes the truncated protein NK2.