Scatter factor-hepatocyte growth factor elevation in the serum of patients with prostate cancer

Expression of VEGF, EGF and HGF in early- and late-stage colorectal cancer

The heterogenous nature of colorectal cancer (CRC) highlights the need for a better understanding of the growth factors that affect tumour growth and cancer progression. The aim of the present study was to evaluate the role of epidermal growth factor (EGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) in the early (I and II) and late (III and IV) stages of CRC. The serum levels and mRNA expression (n=30) of the aforementioned growth factors were measured and immunohistochemistry (n=20) was performed in patients with CRC. Histological examination revealed comparable distribution of early-stage [I: 8 (26.7%) and II: 7 (23.3%)] and late-stage [III: 8 (26.7%) and IV: 7 (23.3%)] CRC. The mean serum concentrations of VEGF during the early (152.9±14.5 vs. 88.39±3.99 pg/ml; P=0.001) and late (182.7±25.8 vs. 88.39±3.99 pg/ml; P=0.002) stages were significantly higher compared with those in controls. Similarly, the mean serum concentrations of EGF in the early (409.4±7.96 vs. 153.7±13.8 pg/ml; P=0.05) and HGF in the late (90.4±17.4 vs. 56.9±4.97 pg/ml; P=0.05) stages were significantly higher compared with those in controls. The serum concentrations of VEGF, EGF and HGF were comparable between the early and late stages of CRC. Compared to normal tissues, the mRNA expression of both VEGF (P<0.001) and HGF (P<0.01) was upregulated in early-stage and downregulated in late-stage CRC. The expression of EGF remained significantly elevated during both the early and late stages of CRC (P<0.01). Histopathological analyses confirmed increased expression of VEGF in cancerous tissues compared with that in normal tissues. The present study emphasized the need for monitoring the serum levels and tissue expression of growth factors to fully elucidate their role in patients with CRC.

Evodiamine Mitigates Cellular Growth and Promotes Apoptosis by Targeting the c-Met Pathway in Prostate Cancer Cells

Evodiamine (EVO) is an indoloquinazoline alkaloid that exerts its various anti-oncogenic actions by blocking phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), mitogen-activated protein kinase (MAPK), c-Met, and nuclear factor kappa B (NF-κB) signaling pathways, thus leading to apoptosis of tumor cells. We investigated the ability of EVO to affect hepatocyte growth factor (HGF)-induced c-Met/Src/STAT3 activation cascades in castration-resistant prostate cancer (CRPC). First, we noted that EVO showed cytotoxicity and anti-proliferation activities in PC-3 and DU145 cells. Next, we found that EVO markedly inhibited HGF-induced c-Met/Src/STAT3 phosphorylation and impaired the nuclear translocation of STAT3 protein. Then, we noted that EVO arrested the cell cycle, caused apoptosis, and downregulated the expression of various carcinogenic markers such as B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), cyclin D1, cyclooxygenase 2 (COX-2), survivin, vascular endothelial growth factor (VEGF), and matrix metallopeptidases 9 (MMP-9). Moreover, it was observed that in cPC-3 and DU145 cells transfected with c-Met small interfering RNA (siRNA), Src/STAT3 activation was also mitigated and led to a decrease in EVO-induced apoptotic cell death. According to our results, EVO can abrogate the activation of the c-Met/Src/STAT3 signaling axis and thus plays a role as a robust suppressor of tumor cell survival, proliferation, and angiogenesis.

Phase II randomized, double-blind, placebo-controlled study of tivantinib in men with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC)

Background Tivantinib is a non-ATP competitive inhibitor of c-MET receptor tyrosine kinase that may have additional cytotoxic mechanisms including tubulin inhibition. Prostate cancer demonstrates higher c-MET expression as the disease progresses to more advanced stages and to a castration resistant state. Methods 80 patients (pts) with asymptomatic or minimally symptomatic mCRPC were assigned (2:1) to either tivantinib 360 mg PO BID or placebo (P). The primary endpoint was progression free survival (PFS). Results Of the 80 pts. enrolled, 78 (52 tivantinib, 26 P) received treatment and were evaluable. Median follow up is 8.9 months (range: 2.3 to 19.6 months). Patients treated with tivantinib had significantly better PFS vs. those treated with placebo (medians: 5.5 mo vs 3.7 mo, respectively; HR = 0.55, 95% CI: 0.33 to 0.90; p = 0.02). Grade 3 febrile neutropenia was seen in 1 patient on tivantinib while grade 3 and 4 neutropenia was recorded in 1 patient each on tivantinib and placebo. Grade 3 sinus bradycardia was recorded in two men on the tivantinib arm. Conclusions Tivantinib has mild toxicity and improved PFS in men with asymptomatic or minimally symptomatic mCRPC.

KLK14 interactions with HAI-1 and HAI-2 serine protease inhibitors: A molecular dynamics and relative free-energy calculations study

Kallikrein 14 (KLK14) is a serine protease linked to several pathologies including prostate cancer and positively correlates with Gleason score. Though KLK14 functioning in cancer is poorly understood, it has been implicated in HGF/Met signaling, given that KLK14 proteolytically inhibits HGF activator-inhibitor 1 (HAI-1), which strongly inhibits pro-HGF activators, thereby contributing to tumor progression. In this work, KLK14 binding to either hepatocyte growth factor activator inhibitor type-1 (HAI-1) or type-2 (HAI-2) was essayed using homology modeling, molecular dynamic simulations and free-energy calculations through MM/PBSA and MM/GBSA. KLK14 was successfully modeled. Calculated free energies suggested higher binding affinity for the KLK14/HAI-1 interaction than for KLK14/HAI-2. This difference in binding affinity is largely explained by the higher stability of the hydrogen-bond networks in KLK14/HAI-1 along the simulation trajectory. A key arginine residue in both HAI-1 and HAI-2 is responsible for their interaction with the S1 pocket in KLK14. Additionally, MM/GBSA free-energy decomposition postulates that KLK14 Asp174 and Trp196 are hotspots for binding HAI-1 and HAI-2.

Heteronemin Is a Novel c-Met/STAT3 Inhibitor Against Advanced Prostate Cancer Cells

BACKGROUND

Prostate cancer is one of the most prevalent cancers in men worldwide. Aberrant activation of c-Met/signal transducer and activator of transcription-3 (STAT3) signaling is involved in prostate carcinogenesis, underscoring the demand for developing c-Met/STAT3-targeting drugs. Thus, we first utilized virtual screening strategy to identify STAT3-inhibiting marine compound, heteronemin, and then validated the STAT3-inhibiting function of heteronemin in prostate cancer cells.

METHODS

Human prostate cancer LNCaP, DU145, and PC-3 cell lines were treated with heteronemin for 24 hr, then the cell viability was evaluated by MTT assay. Flow cytometry was performed to analyze the apoptosis in heteronemin-treated cells. Western blot and quantitative real-time PCR were executed to further confirm the c-Met/STAT3 signaling inhibition by heteronemin in DU145 and PC-3 cells.

RESULTS

In this study, we employed the virtual screening strategy to identify heteronemin, a spongean sesterterpene, as a potential STAT3 inhibitor from Taiwan marine drugs library. Application of heteronemin potently suppressed the viability and anchorage-independent growth of human prostate cancer cells. Besides, heteronemin induced apoptosis in prostate cancer cells by activation of both intrinsic (caspase-9) and extrinsic (caspase-8) apoptotic pathways. By luciferase assay and expression analysis, it was confirmed that heteronemin inhibited the phosphorylation of c-Met/src/STAT3 signaling axis, STAT3-driven luciferase activities and expression of STAT3-regulated genes including Bcl-xL, Bcl-2, and Cyclin D1. Finally, heteronemin effectively antagonized the hepatocyte growth factor (HGF)-stimulated c-Met/STAT3 activation as well as the proliferation and colonies formation in refractory prostate cancer cells.

CONCLUSIONS

These findings suggest that heteronemin may constitute a novel c-Met/STAT3-targeting agent for prostate cancer. Prostate 76:1469-1483, 2016. © 2016 Wiley Periodicals, Inc.

Tumor and Plasma Met Levels in Non-Metastatic Prostate Cancer

Objective

To measure Met protein content in prostate biopsies guided by fused magnetic resonance and ultrasound imaging, and to measure soluble Met (sMet) protein concentration in plasma samples from patients presenting evidence of prostate cancer.

Patients and Methods

345 patients had plasma samples drawn prior to image-guided biopsy of the prostate. Of these, 32% had benign biopsies. Of the 236 that were positive for prostate adenocarcinoma (PCa), 132 treated by total prostatectomy had Gleason scores of 6 (17%), 7, (55%), 8 (16%), or 9–10 (12%). 23% had evidence of local invasion. Plasma samples were also obtained from 80 healthy volunteers. Tissue Met and plasma sMet were measured by two-site immunoassay; values were compared among clinically defined groups using non-parametric statistical tests to determine significant differences or correlations.

Results

PCa tumor Met correlated significantly with plasma sMet, but median values were similar among benign and malignant groups. Median plasma sMet values were also similar among those groups, although both medians were significantly above normal. Median Met content in primary PCa tumors and sMet concentrations were independent of Gleason score, final pathologic stage and age.

Conclusion

Plasma sMet is not predictive of PCa or its severity in patients with organ-confined or locally invasive disease. Quantitative analysis of Met protein content and activation state in PCa tumor biopsy samples was highly feasible and may have value in follow-up to genomic and/or transcriptomic-based screens that show evidence of oncogenically relevant MET gene features that occur at relatively low frequency in non-metastatic PCa.

Hepatocyte growth factor increases the invasive potential of PC-3 human prostate cancer cells via an ERK/MAPK and Zeb-1 signaling pathway

Hepatocyte growth factor (HGF) has been implicated in epithelial-mesenchymal transition (EMT) in numerous types of cancer. However, to the best of our knowledge, there has been no previous evidence that HGF has a role in prostate cancer. The present study aimed to investigate the effect of HGF on EMT and invasive potential, as well as the underlying molecular mechanisms, in a human prostate cancer cell line. Therefore, PC-3 cells were treated with various concentrations of HGF for varying durations. EMT-associated proteins, including E-cadherin and vimentin, were examined by western blot analysis. The effects of HGF on cell proliferation, migration, invasion and tumorigenicity were assessed using MTT, wound-healing, Transwell and soft-agar assays. Subsequently, the role of c-Met in the mediation of EMT-like changes was investigated using reverse transcription-polymerase chain reaction, western blot analysis and gene knockdown by small interfering RNA. Finally, western blot analysis was used to quantify the expression of a downstream transcription factor and extracellular signal-related kinase/mitogen activated protein kinase (ERK/MAPK) signaling pathway proteins. The results indicated that treatment with HGF induced EMT-like changes and enhanced the invasive potential of PC-3 cells. There was an increase in the expression of ERK, phosphorylated-ERK and zinc finger E-box binding homeobox-1 (Zeb-1), suggesting that EMT-like changes may be mediated through the ERK/MAPK and Zeb-1 signaling pathway. Furthermore, HGF-mediated EMT-like changes were associated with c-Met activation, and these changes were able to be blocked by c-Met knockdown. The present study demonstrated that HGF-induced EMT increased the invasive potential of PC-3 human prostate cancer cells through activating the ERK/MAPK and Zeb-1 signaling pathway.

Targeted treatments for metastatic esophageal squamous cell cancer

Squamous cell carcinoma, one of the two major sub-types of esophageal carcinomas, constitutes the great majority of tumors in the upper and middle third of the organ. Declining in incidence in western countries, it continues to be a significant public health problem in the far east. Targeted treatments are novel therapies introduced in the clinical therapeutic armamentarium of oncology in the last 10-15 years. They represent a rational way of treating various cancers based on their molecular lesions. Although no such agent has been approved so far for the treatment of esophageal squamous cell carcinomas (ESCC), several are in clinical trials and several others have displayed pre-clinical activity that would justify the efforts and risks of pursuing their clinical development in this disease. This paper discusses some of these targeted agents in more advanced development in metastatic ESCC, as well as some promising drugs with pre-clinical or initial clinical data in the disease.

Targeted MET inhibition in castration-resistant prostate cancer: a randomized phase II study and biomarker analysis with rilotumumab plus mitoxantrone and prednisone

PURPOSE

To evaluate the efficacy, safety, biomarkers, and pharmacokinetics of rilotumumab, a fully human, monoclonal antibody against hepatocyte growth factor (HGF)/scatter factor, combined with mitoxantrone and prednisone (MP) in patients with castration-resistant prostate cancer (CRPC).

EXPERIMENTAL DESIGN

This double-blinded phase II study randomized (1:1:1) patients with progressive, taxane-refractory CRPC to receive MP (12 mg/m(2) i.v. day 1, 5 mg twice a day orally days 1-21, respectively) plus 15 mg/kg rilotumumab, 7.5 mg/kg rilotumumab, or placebo (i.v. day 1) every 3 weeks. The primary endpoint was overall survival (OS).

RESULTS

One hundred and forty-four patients were randomized. Median OS was 12.2 versus 11.1 months [HR, 1.10; 80% confidence interval (CI), 0.82-1.48] in the combined rilotumumab versus control arms. Median progression-free survival was 3.0 versus 2.9 months (HR, 1.02; 80% CI, 0.79-1.31). Treatment appeared well tolerated with peripheral edema (24% vs. 8%) being more common with rilotumumab. A trend toward unfavorable OS was observed in patients with high tumor MET expression regardless of treatment. Soluble MET levels increased in all treatment arms. Total HGF levels increased in the rilotumumab arms. Rilotumumab showed linear pharmacokinetics when co-administered with MP.

CONCLUSIONS

Rilotumumab plus MP had manageable toxicities and showed no efficacy improvements in this estimation study. High tumor MET expression may identify patients with CRPC with poorer prognosis.

Validation of a multiplex immunoassay for serum angiogenic factors as biomarkers for aggressive prostate cancer

BACKGROUND

Assays used for discovery of biomarkers should be robust and high-throughput, capable of analyzing a sufficiently large number of samples over a sufficiently long period of time with good precision.

METHODS

We evaluated the analytical performance of the Bio-Plex Pro™ Human Cancer Biomarker Panel 1, a 16-plex multiplex immunoassay, in serum for composite profiling of angiogenic factors. Because prostate cancer progression and metastasis are pathological events closely linked to angiogenesis, serum angiogenic factors are ideal candidates as prognostic biomarkers.

RESULTS

Our 5-day evaluation indicated that all 16 assays in the panel had good reproducibility (total precisions over 5 independent plates in 5 days of <20%), adequate sensitivity (LOQs of majority of the assays less than 100 pg/ml), and wide dynamic ranges (linearity of majority of the assays spanning across 3 logs in concentrations).

CONCLUSIONS

Applying the panel to sera from prostate cancer patients with Gleason scores of 6, 7, 8-10, tumor stages that correlated with clinical outcome, we identified that the levels of sTIE-2, a soluble form of the transmembrane tyrosine kinase receptor for angiopoietins, were increased in patients with Gleason score of 8-10. Future studies are necessary to determine whether sTIE-2 could be used as a prognostic biomarker for identifying aggressive prostate cancer.

The PCa Tumor Microenvironment

The tumor microenvironment (TME) is a very complex niche that consists of multiple cell types, supportive matrix and soluble factors. Cells in the TME consist of both host cells that are present at tumor site at the onset of tumor growth and cells that are recruited in either response to tumor- or host-derived factors. PCa (PCa) thrives on crosstalk between tumor cells and the TME. Crosstalk results in an orchestrated evolution of both the tumor and microenvironment as the tumor progresses. The TME reacts to PCa-produced soluble factors as well as direct interaction with PCa cells. In return, the TME produces soluble factors, structural support and direct contact interactions that influence the establishment and progression of PCa. In this review, we focus on the host side of the equation to provide a foundation for understanding how different aspects of the TME contribute to PCa progression. We discuss immune effector cells, specialized niches, such as the vascular and bone marrow, and several key protein factors that mediate host effects on PCa. This discussion highlights the concept that the TME offers a potentially very fertile target for PCa therapy.

Differences in phenotype and gene expression of prostate stromal cells from patients of varying ages and their influence on tumour formation by prostate epithelial cells

Prostate cancer (PCa) is an age-related disease, and the stromal microenvironment plays an important role in prostatic malignant progression. However, the differences in prostate stromal cells present in young and old tissue are still obscure. We established primary cultured stromal cells from normal prostatic peripheral zone (PZ) of donors of varying ages and found that cultured stromal cells from old donors (PZ-old) were more enlarged and polygonal than those from young donors (PZ-young). Furthermore, based on immunocytochemical and ultrastructural analysis, the components of stromal cells changed from a majority of fibroblasts to a mixture of fibroblasts and myofibroblasts with increasing donor age. Using a three-dimensional in vitro culture system, we found that PZ-old stromal cells could enhance the proliferation, migration and invasion of cocultured benign BPH-1 and PC-3 cells. Using an in vivo tissue recombination system, we also found that PZ-old stromal cells are more effective than PZ-young cells in promoting tumour formation by BPH-1 cells of high passage (>100) and PC-3 cells. To probe the possible mechanism of these effects, we performed cDNA microarray analysis and profiled 509 upregulated genes and 188 downregulated genes in PZ-old cells. Among the changed genes, we found genes coding for a subset of paracrine factors that are capable of influencing adjacent epithelial cells; these include hepatocyte growth factor (HGF), fibroblast growth factor 5 (FGF5), insulin-like growth factor 2 (IGF2), insulin-like growth factor-binding protein 4 (IGFBP4), IGFBP5 and matrix metallopeptidase 1 (MMP1). Changes in the expression of these genes were further confirmed by quantitative real-time polymerase chain reaction (PCR), Western blotting and enzyme-linked immunosorbent assays. Overall, our findings indicate that stromal cells from prostate PZ of old donors are more active than similar cells from young donors in promoting the malignant process of adjacent epithelial cells. This finding hints at a new potential strategy for the prevention of PCa.

The polyphenol epigallocatechin-3-gallate affects lipid rafts to block activation of the c-Met receptor in prostate cancer cells

The HGF/c-Met pathway is an important regulator of signaling pathways responsible for invasion and metastasis of most human cancers, including prostate cancer. Exposure of DU145 prostate tumor cells to HGF stimulates the PI3-kinase and MAPK pathways, leading to increased scattering, motility, and invasion, which was prevented by the addition of EGCG. EGCG acted at the level of preventing phosphorylation of tyrosines 1234/1235 in the kinase domain of the c-Met receptor without effecting dimerization. HGF-induced changes were independent of the formation of reactive oxygen species, suggesting that EGCG functioned independent of its antioxidant ability. ECG, another tea polyphenol, was as effective as EGCG, while EGC and EC were less effective. EGCG added up to 4 h after the addition of HGF still blocked cell scattering and reduced the HGF-induced phosphorylation of c-Met, Akt, and Erk, suggesting that EGCG could act both by preventing activation of c-Met by HGF and by attenuating the activity of pathways already induced by HGF. HGF did not activate the MAPK and PI3-K pathways in cells treated with methyl-beta-cyclodextrin (mCD) to remove cholesterol. Furthermore, subcellular fractionation approaches demonstrated that only phosphorylated c-Met accumulated in Triton X-100 membrane insoluble fractions, supporting a role for lipid rafts in regulating c-Met signaling. Finally, EGCG treatment inhibited DiIC16 incorporation into membrane lipid ordered domains, and cholesterol partially inhibited the EGCG effects on signaling. Together, these results suggest that green tea polyphenols with the R1 galloyl group prevent activation of the c-Met receptor by altering the structure or function of lipid rafts.

Stromal hyaluronan interaction with epithelial CD44 variants promotes prostate cancer invasiveness by augmenting expression and function of hepatocyte growth factor and androgen receptor

The main aim of our study is to determine the significance of the stromal microenvironment in the malignant behavior of prostate cancer. The stroma-derived growth factors/cytokines and hyaluronan act in autocrine/paracrine ways with their receptors, including receptor-tyrosine kinases and CD44 variants (CD44v), to potentiate and support tumor epithelial cell survival. Overexpression of hyaluronan, CD44v9 variants, and stroma-derived growth factors/cytokines are specific features in many cancers, including prostate cancer. Androgen/androgen receptor interaction has a critical role in regulating prostate cancer growth. Our previous study showed that 1) that increased synthesis of hyaluronan in normal epithelial cells promotes expression of CD44 variants; 2) hyaluronan interaction with CD44v6-v9 promotes activation of receptor-tyrosine kinase, which stimulates phosphatidylinositol 3-kinase-induced cell survival pathways; and 3) CD44v6/short hairpin RNA reduces colon tumor growth in vivo (Misra, S., Hascall, V. C., De Giovanni, C., Markwald, R. R., and Ghatak, S. (2009) J. Biol. Chem. 284, 12432–12446). Our results now show that hepatocyte growth factor synthesized by myofibroblasts associated with prostate cancer cells induces activation of HGF-receptor/cMet and stimulates hyaluronan/CD44v9 signaling. This, in turn, stabilizes the androgen receptor functions in prostate cancer cells. The stroma-derived HGF induces a lipid raft-associated signaling complex that contains CD44v9, cMet/phosphatidylinositol 3-kinase, HSP90 and androgen receptor. CD44v9/short hairpin RNA reverses the assembly of these components in the complex and inhibits androgen receptor function. Our results provide new insight into the hyaluronan/CD44v9-regulated androgen receptor function and the consequent malignant activities in prostate cancer cells. The present study describes a physiologically relevant in vitro model for studying the molecular mechanisms by which stroma-derived HGF and hyaluronan influence androgen receptor and CD44 functions in the secretory epithelia during prostate carcinogenesis.

Serum hepatocyte growth factor as a prognostic marker for stage II or III colorectal cancer patients

We previously reported that a combination of serum hepatocyte growth factor (HGF) and carcinoembryonic antigen (CEA) was useful for selecting early-stage colorectal cancer patients with aggressive disease. The aim of the present study was to determine whether serum HGF could provide CEA-independent prognostic information on patients undergoing surgery with curative intent. Serum samples were collected from 184 patients with colorectal cancer and 30 controls. Reverse-transcription polymerase chain reaction was used to detect HGF expression in colorectal cancer cell lines. Serum and tissue levels of HGF were measured by enzyme-linked immunosorbent assay. The serum HGF levels in colorectal cancer patients were compared with those in healthy controls, and we retrospectively assessed the association between serum HGF levels and clinicopathological findings and survival. Expression of HGF was significantly higher in colorectal cancer tissues compared with non-tumor tissues. The serum HGF levels were closely correlated with the HGF levels in cancer tissue. The mean serum HGF level in patients was significantly higher than that in controls, and significantly higher in patients with large tumor, lymph-node involvement and distant metastasis. According to the receiver operating characteristic (ROC) analysis, elevated serum HGF levels can predict patients with larger tumor, lymph-node and distant metastasis. Elevated serum HGF level demonstrated a significant association with poor survival, and was only an independent risk factor for poor survival in Stage II or/and III. Elevated serum HGF level is significantly associated with colorectal cancer development, lymph or distant invasive phenotypes and survival, especially in Stage II or III patients.

Urine analysis and protein networking identify met as a marker of metastatic prostate cancer

PURPOSE

Metastatic prostate cancer is a major cause of death of men in the United States. Expression of met, a receptor tyrosine kinase, has been associated with progression of prostate cancer.

EXPERIMENTAL DESIGN

To investigate met as a biomarker of disease progression, urinary met was evaluated via ELISA in men with localized (n = 75) and metastatic (n = 81) prostate cancer. Boxplot analysis was used to compare the distribution of met values between each group. We estimated a receiver operating characteristic curve and the associated area under the curve to summarize the diagnostic accuracy of met for distinguishing between localized and metastatic disease. Protein-protein interaction networking via yeast two-hybrid technology supplemented by Ingenuity Pathway Analysis and Human Interactome was used to elucidate proteins and pathways related to met that may contribute to progression of disease.

RESULTS

Met distribution was significantly different between the metastatic group and the group with localized prostate cancer and people with no evidence of cancer (P < 0.0001). The area under the curve for localized and metastatic disease was 0.90, with a 95% confidence interval of 0.84 to 0.95. Yeast two-hybrid technology, Ingenuity Pathway Analysis, and Human Interactome identified 89 proteins that interact with met, of which 40 have previously been associated with metastatic prostate cancer.

CONCLUSION

Urinary met may provide a noninvasive biomarker indicative of metastatic prostate cancer and may be a central regulator of multiple pathways involved in prostate cancer progression.

Tea polyphenols decrease serum levels of prostate-specific antigen, hepatocyte growth factor, and vascular endothelial growth factor in prostate cancer patients and inhibit production of hepatocyte growth factor and vascular endothelial growth factor in vitro

The purpose of this study was to determine the effects of short-term supplementation with the active compounds in green tea on serum biomarkers in patients with prostate cancer. Twenty-six men with positive prostate biopsies and scheduled for radical prostatectomy were given daily doses of Polyphenon E, which contained 800 mg of (-)-epigallocatechin-3-gallate (EGCG) and lesser amounts of (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin-3-gallate (a total of 1.3 g of tea polyphenols), until time of radical prostatectomy. Serum was collected before initiation of the drug study and on the day of prostatectomy. Serum biomarkers hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF)-I, IGF binding protein-3 (IGFBP-3), and prostate-specific antigen (PSA) were analyzed by ELISA. Toxicity was monitored primarily through liver function enzymes. Changes in serum components were analyzed statistically using the Wilcoxon signed rank test. Cancer-associated fibroblasts were treated with EGCG, and HGF and VEGF protein and mRNA levels were measured. HGF, VEGF, PSA, IGF-I, IGFBP-3, and the IGF-I/IGFBP-3 ratio decreased significantly during the study. All of the liver function tests also decreased, five of them significantly: total protein, albumin, aspartate aminotransferase, alkaline phosphatase, and amylase. The decrease in HGF and VEGF was confirmed in prostate cancer-associated fibroblasts in vitro. Our results show a significant reduction in serum levels of PSA, HGF, and VEGF in men with prostate cancer after brief treatment with EGCG (Polyphenon E), with no elevation of liver enzymes. These findings support a potential role for Polyphenon E in the treatment or prevention of prostate cancer.

Serum active hepatocyte growth factor (AHGF) in benign prostatic disease and prostate cancer

BACKGROUND

Hepatocyte growth factor (HGF) is secreted as an inactive single-chain precursor called pro-HGF. Pro-HGF is converted to an active two-chain form by HGF activator and matriptase. We attempted to clarify whether serum levels of active HGF (AHGF) could be used as a marker of prostate cancer.

METHODS

Serum levels of AHGF and total HGF (THGF; pro-HGF + AHGF) were measured by enzyme-linked immunosorbent assay in 38 patients with benign prostatic disease and 160 patients with prostate cancer.

RESULTS

Serum levels of AHGF in patients with untreated prostate cancer (0.37 +/- 0.12 ng/ml) were significantly higher than those in patients with benign prostatic disease (0.28 +/- 0.08 ng/ml) (P = 0.0001). Serum AHGF levels were increased in patients with stage D or D3 compared with stage B. In addition, there were significant differences in serum AHGF levels between patients with well-differentiated and poorly differentiated adenocarcinoma. Furthermore, the mean serum AHGF/THGF ratio in patients with stage D3 prostate cancer was significantly higher than that in patients with stage B.

CONCLUSIONS

AHGF may be a potential tumor marker for prostate cancer. Further studies in large groups of patients are needed to define the clinical value of AHGF.

Predictive value of plasma hepatocyte growth factor/scatter factor levels in patients with clinically localized prostate cancer

PURPOSE

Hepatocyte growth factor/scatter factor (HGF/SF) is a multifunctional cytokine that is involved in cancer growth, motility, invasion, and angiogenesis. We assessed whether preoperative plasma levels of HGF can enhance the accuracy of standard models for predicting pathologic features and clinical outcomes.

EXPERIMENTAL DESIGN

The study comprised 421 consecutive patients treated with radical prostatectomy and bilateral lymphadenectomy for clinically localized prostatic adenocarcinoma. HGF/SF was measured using a commercially available immunoassay. Multivariate logistic regression was used to assess the relationship between plasma HGF/SF and pathologic features. Multivariate Cox regression was used to predict disease recurrence. One thousand bootstrap replicates were created for internal validation and predictive accuracies were estimated for each model.

RESULTS

Plasma HGF/SF levels were significantly elevated in patients with lymph node and/or seminal vesicle invasion (P < 0.0001 and P = 0.007, respectively). Preoperative plasma HGF/SF level was an independent predictor of lymph node invasion [odds ratio (OR) for every 100 pg/mL increase in HGF/SF, 1.82; 95% confidence interval (95% CI), 1.33-2.49] and seminal vesicle invasion (OR, 1.18; 95% CI, 1.06-1.3). Addition of HGF/SF increased the accuracy of a base model that included standard preoperative variables for prediction of lymph node invasion by 6.7% (predictive accuracy, 98.4%). HGF/SF also independently predicted disease recurrence after surgery (hazard ratio, 1.07; 95% CI, 1.0-1.15).

CONCLUSIONS

Preoperative plasma level of HGF/SF is an independent predictor of prostate cancer metastasis to lymph nodes and disease recurrence after surgery. Use of HGF may help in therapeutic decision-making and enrollment into clinical trials.

The Tumor Microenvironment: Key to Early Detection

The tumor microenvironment plays an important role equal to the tumor cell population in the progression of cancer. Consisting of stromal fibroblasts, inflammatory cells, components of the vasculature, normal epithelia, and extracellular matrix, the surrounding environment interacts or "cross-talks" with tumor cells through the release of growth factors, cytokines, proteases, and other bioactive molecules. Tumor growth, formation of new vascular networks, evasion of the host immune system, and invasion and metastasis are processes that co-evolve and become finely optimized and regulated within the tumor microenvironment. However, relatively recent reports on three areas of study have come together to add new levels of complexity to the tumor microenvironment. These include ectodomain shedding of proteins, shedding of membrane-derived vesicles, and novel roles for phospholipids. These dynamic changes that take place in the tumor microenvironment provide new avenues for study and for the early detection of cancer, whereas proteomic technologies provide the means to detect these unique proteins and lipids. Here we review the evolving concepts of the tumor microenvironment that, together with advances in proteomic technologies, hold the promise to facilitate the detection of early-stage cancer.

Cytokine profiling of prostatic fluid from cancerous prostate glands identifies cytokines associated with extent of tumor and inflammation

BACKGROUND

Cytokines are key mediators of inflammation that may relate to prostate cancer initiation and progression, and that may be useful markers of prostatic neoplasia and related inflammation. In order to better understand the relationship between cytokines and prostate cancer, we profiled cytokines in prostatic fluids obtained from cancerous prostate glands and correlated them to both cancer status and inflammatory grade.

METHODS

Prostatic fluid was collected from fresh radical prostatectomy specimens and analyzed by cytokine antibody microarray. For comparison, cases were selected from patients with either minimal or extensive cancer volume on final pathology. Among the cytokines with the greatest difference between the tumor volume groups, eight had their levels quantitated by ELISA. In addition, the grade of prostatic inflammation by neutrophils, macrophages and lymphocytes was scored for each case and examined for correlations with cytokine levels.

RESULTS

Among 174 cytokines analyzed, HGF was the most increased (6.57-fold), and along with IL18Bpa was significantly elevated in patients with extensive disease compared to those with minimal disease. IL17, GITR, and ICAM-1 were elevated in specimens with significant neutrophilic inflammation into gland lumina, and IL18Bpa, IL17, GITR, and ICAM-1 were elevated in specimens with significant lymphocytic inflammation in prostatic stroma.

CONCLUSIONS

Prostatic fluid cytokines were identified that may be useful for early cancer detection and prognostication efforts and for assessment of prostatic inflammation, particularly if they can be found not only in prostatic fluids obtained ex vivo, but in expressed prostatic secretions or urine samples from men with prostates still in situ.

Serum hepatocyte growth factor as a marker of tumor activity in head and neck squamous cell carcinoma

Hepatocyte growth factor (HGF) has previously been reported to be elevated in the serum of patients with malignancy, including breast, colorectal and gastric cancers. Here, we evaluated the correlation between serum HGF and the progression of head and neck squamous cell carcinoma (HNSCC). The mean serum HGF levels in 71 healthy control subjects, 78 patients with primary HNSCC, and eight patients with recurrent HNSCC were 0.538+/-0.163, 0.701+/-0.252, and 0.925+/-0.349ng/ml, respectively. The increase in the HGF level was significantly correlated with tumor stage progression. The HGF level had decreased to normal at 1 month after curative resection of the tumors. During follow-up for several months, the HGF level significantly increased in recurrent HNSCC patients, whereas there was no increase in nonrecurrent patients. Our data suggest that serum HGF is significantly corrected with tumor progression and may be a strong predictor of recurrence in HNSCC.

Genome-wide expression profiling reveals transcriptomic variation and perturbed gene networks in androgen-dependent and androgen-independent prostate cancer cells

Previously, we have developed a unique in vitro LNCaP cell model, which includes androgen-dependent (LNCaP-C33), androgen-independent (LNCaP-C81) and an intermediate phenotype (LNCaP-C51) cell lines resembling the stages of prostate cancer progression to hormone independence. This model is advantageous in overcoming the heterogeneity associated with the prostate cancer up to a certain extent. We characterized and compared the gene expression profiles in LNCaP-C33 (androgen-dependent) and LNCaP-C81 (androgen-independent) cells using Affymetrix GeneChip array analyses. Multiple genes were identified exhibiting differential expression during androgen-independent progression. Among the important genes upregulated in androgen-independent cells were PCDH7, TPTE, TSPY, EPHA3, HGF, MET, EGF, TEM8, etc., whereas many candidate tumor suppressor genes (HTATIP2, CDKN2A, CDKN2B, CDKN1C, TP53, TP73, ICAM1, SOCS1/2, SPRY2, PPP2CA, PPP3CA, etc.) were decreased. Pathway prediction analysis identified important gene networks associated with growth-promoting and apoptotic signaling that were perturbed during androgen-independent progression. Further investigation of one of the genes, PPP2CA, which encodes the catalytic subunit of a serine phosphatase PP2A, a potent tumor suppressor, revealed that its expression was decreased in prostate cancer compared to adjacent normal/benign tissue. Furthermore, the downregulated expression of PPP2CA was significantly correlated with tumor stage and Gleason grade. Future studies on the identified differentially expressed genes and signaling pathways may be helpful in understanding the biology of prostate cancer progression and prove useful in developing novel prognostic biomarkers and therapy for androgen-refractory prostate cancer.

Hepatocyte growth factor and interleukin-6 in combination with prostate volume are possible prostate cancer tumor markers in patients with gray-zone PSA levels

The aim was to assess whether hepatocyte growth factor (HGF) and interleukin (IL)-6 in combination with prostate volume are able to accurately detect prostate cancer in patients with gray-zone prostate-specific antigen (PSA) levels. A total of 159 patients with PSA levels of <10 ng ml(-1) were enrolled. Forty-two (35.3%) were diagnosed with prostate cancer, whereas 117 (64.7%) had no cancer and were used as benign group. HGF and IL-6 density (HGFD and IL-6D, respectively) values were calculated by dividing serum HGF and IL-6 levels with prostate volume. Median IL-6 (2.3 pg ml(-1)) levels for the prostate cancer group were significantly higher than those for the benign group before adjustment for age (1.7 pg ml(-1)) (P=0.0098). After age adjustments, median IL-6 (2.17 pg ml(-1)), HGFD (0.00972 ng ml(-1) cm(-3)), and IL-6D (0.0848 pg ml(-1) cm(-3)) values for the prostate cancer group were significantly higher than those for the benign group (IL-6, 1.78 pg ml(-1); HGFD, 0.00732 ng/ml/cc; and IL-6D, 0.049 pg/ml/cc; P=0.0416, 0.007 and 0.0005, respectively). In receiver operating characteristic analyses, the areas under the curves for HGFD (0.64) and IL-6D (0.68) were significantly greater than those for HGF (0.52) and IL-6 (0.61) (P=0.0006 and 0.019, respectively). With an HGFD cutoff value of 0.00392 ng ml(-1) cm(-3) (sensitivity=100%, specificity=11%), 11.1% of the benign group were able to avoid unnecessary biopsies without missing prostate cancer. HGF and IL-6 levels in combination with prostate volume were shown to be useful parameters for prostate cancer screening in patients with gray-zone PSA levels.

Novel xenograft model expressing human hepatocyte growth factor shows ligand-dependent growth of c-Met-expressing tumors

c-Met, a receptor tyrosine kinase responsible for cellular migration, invasion, and proliferation, is overexpressed in human cancers. Although ligand-independent c-Met activation has been described, the majority of tumors are ligand dependent and rely on binding of hepatocyte growth factor (HGF) for receptor activation. Both receptor and ligand are attractive therapeutic targets; however, preclinical models are limited because murine HGF does not activate human c-Met. The goal of this study was to develop a xenograft model in which human HGF (hHGF) is produced in a controllable fashion in the mouse. Severe combined immunodeficient mice were treated with adenovirus encoding the hHGF transgene (Ad-hHGF) via tail vein injection, and transgene expression was determined by the presence of hHGF mRNA in mouse tissue and hHGF in serum. Ad-hHGF administration to severe combined immunodeficient mice resulted in hHGF production that was (a) dependent on quantity of virus delivered; (b) biologically active, resulting in liver hypertrophy; and (c) sustainable over 40 days. In this model, the ligand-dependent human tumor cell line SW1417 showed enhanced tumor growth, whereas the ligand-independent cell lines SW480 and GTL-16 showed no augmented tumor growth. This novel xenograft model is ideal for investigating c-Met/HGF-dependent human tumor progression and for evaluating c-Met targeted therapy.

Serum levels of hepatocyte growth factor/scatter factor in patients with liver metastases from breast cancer

OBJECTIVE

Recent studies have shown that the pleiotropic cytokine hepatocyte growth factor/scatter factor (HGF/SF) and its receptor c-Met play major roles in the malignant progression of numerous tumors. For patients with breast cancer liver metastases, increased serum levels of HGF/SF have been reported. We studied the relationship between the clinical course of the disease and the serum levels of HGF/SF in such patients.

METHODS

We examined 51 patients treated for breast cancer liver metastases. Serum concentrations of HGF/SF were measured before each therapy cycle and compared to the corresponding tumor marker levels.

RESULTS

Mean serum levels of HGF/SF in patients with liver metastases were increased above the reported reference levels of primary breast cancer patients. Serum levels of HGF/SF were correlated with tumor marker levels in a logarithmic relation (r = 0.47, p < 0.001). In some cases serum concentrations of HGF/SF changed similarly to the course of the corresponding tumor markers.

CONCLUSIONS

Serum levels of HGF/SF are associated with the clinical course of metastatic breast cancer patients with liver metastases. Further studies are required to clarify the potential value of the HGF/SF serum concentration as a tumor marker. HGF/SF and its receptor c-Met should be further evaluated as therapeutic targets.

Combined measurement of hepatocyte growth factor and carcinoembryonic antigen as a prognostic marker for patients with dukes a and B colorectal cancer: results of a five-year study

PURPOSE

There is no marker capable of differentiating patients with Dukes A and B colorectal cancer with aggressive diseases from those with indolent diseases. We evaluated the results of five years of actuarial survival data to determine whether serial monitoring of serum hepatocyte growth factor could provide prognostic information on these patients.

METHODS

Blood samples of 147 colorectal cancer patients were obtained and the serum concentration of hepatocyte growth factor was measured.

RESULTS

Elevated serum hepatocyte growth factor levels were associated with stage progression. Although the overall positive rate of hepatocyte growth factor in the patients was the same as that of the carcinoembryonic antigen, the positive rate of hepatocyte growth factor in the Dukes A patients was two times higher than that of the carcinoembryonic antigen, and nearly 40 percent of the carcinoembryonic antigen-negative patients had a positive serum hepatocyte growth factor in the Dukes A and B classification. In this subgroup, patients with positive serum hepatocyte growth factor or carcinoembryonic antigen levels had a poorer prognosis, whereas positive serum hepatocyte growth factor level after surgery could predict disease recurrence.

CONCLUSIONS

A combination of serum hepatocyte growth factor and carcinoembryonic antigen tests might be useful for selecting patients with aggressive diseases in Dukes A and B classification.

Prognostic significance of plasma scatter factor/hepatocyte growth factor levels in patients with metastatic hormone- refractory prostate cancer: results from cancer and leukemia group B 150005/9480

BACKGROUND

Scatter factor, also known as hepatocyte growth factor (SF/HGF), is a polypeptide growth factor thought to be important in the growth and spread of prostatic carcinoma.

PATIENTS AND METHODS

Scatter factor/HGF levels in pretreatment plasma samples from 171 men with metastatic hormone-refractory prostate cancer enrolled in CALGB 9480 were quantified by solid-phase, enzyme-linked immunosorbent assay.

RESULTS

The Cox proportional hazards model was used to assess the prognostic importance of SF/HGF with adjustment for established prognostic factors. Median SF/HGF was 991 pg/mL (range, 212-2733 pg/mL). In a univariate analysis, although plasma SF/HGF levels above versus below the median value did not reach statistical significance (P = 0.0862), the cutoff point of > 935 pg/mL was associated with a significant reduction in overall survival (P = 0.0334). Patients with SF/HGF levels > 935 pg/mL experienced a median survival of 15 months compared with 19 months for men with SF/HGF levels < or = 935 pg/mL. In a multivariate analysis, adjusting for SF/HGF, prostate-specific antigen, lactate dehydrogenase, and performance status, only plasma alkaline phosphatase was significantly associated with overall survival (hazard ratio, 1.7; 95% confidence interval, 1.2-2.5; P = 0.0017).

CONCLUSION

Higher plasma levels of SF/HGF in men with hormone-refractory prostate cancer are associated with a decreased patient survival. Currently, SF/HGF levels do not appear to be of value as a contributor to multivariate models for prediction of outcome, but the association with decreased survival suggests that SF/HGF might be a potential target for therapy.

Molecular co-expression of the c-Met oncogene and hepatocyte growth factor in primary colon cancer predicts tumor stage and clinical outcome

INTRODUCTION/HYPOTHESIS

Over-expression of the c-Met receptor tyrosine kinase has been described in a variety of cancers and implicated in tumor progression. Unlike some solid tumors, current evidence indicates that c-Met activation in colon cancer is unrelated to gene mutation, is ligand dependent, and occurs via a paracrine fashion. We hypothesize that over-expression of the c-Met receptor and its ligand, hepatocyte growth factor (HGF) in the tumor microenvironment is associated with tumor progression and metastases.

METHODS

Primary tumor c-Met and HGF mRNA expression was analyzed in 60 colon adenocarcinomas. Receptor and ligand expression was analyzed for correlation and association with clinicopathologic features and outcome.

RESULTS

Compared to adjacent normal mucosa, 69% and 48% of tumors showed a greater than 2- and greater than 10-fold elevation in c-Met mRNA, respectively. Elevated HGF mRNA was noted in 47% of tumors with 19% having a greater than 10-fold increase. Tumor c-Met expression was correlated with HGF expression, and a cohort of 33 patients could be defined with both low c-Met and HGF expression. Compared with the 27 tumors with either high c-Met or HGF, the cohort with low c-Met and HGF expression had fewer nodal and distant metastases as well as improved overall survival (HR=2.3, p<0.05).

CONCLUSION

Evaluation of the c-Met receptor in context of ligand, HGF, allows identification of a metastatic phenotype that correlates with advanced stage and poor survival. c-Met and HGF co-expression in the tumor microenvironment could be useful in the molecular staging of colon cancer and viable therapeutic targets.

Molecular markers in the diagnosis of prostate cancer

The genetic alterations leading to prostate cancer are gradually being discovered. A wide variety of genes have been associated with prostate cancer development as well as tumor progression. Knowledge of gene polymorphisms associated with disease aid in the understanding of important pathways involved in this process and may result in the near future in clinical applications. Urinary molecular markers will soon be available to aid in the decision of repeat prostate biopsies. Recent findings suggest the importance of androgen signaling in disease development and progression. The further understanding of interaction of inflammation, diet, and genetic predisposition will improve risk stratification in the near future.

Inactivation of AR activates HGF/c-Met system in human prostatic carcinoma cells

Clinical studies with prostate cancer tissue indicate that alterations in androgen receptor (AR) or c-Met overexpression are associated with androgen-independent progression. We investigated the interaction between AR and c-Met signaling in human prostate cancer cells. Androgen withdrawal or AR-specific small interfering RNA significantly reduced the growth rate while each maneuver induced the expression of c-Met. Knockdown of both AR and c-Met expression markedly inhibited the cell growth. Furthermore, microarray analysis indicated that the activation of c-Met down-regulated the expression of DNA repair-related genes including 8-oxoguanine DNA glycosylase. Exogenous hepatocyte growth factor also induced the production of intracellular reactive oxygen species and resulted in the accumulation of DNA damages. These results suggested that the activation of c-Met signaling may lead to induction of spontaneous mutations or genomic instability, which may lead to the progression of androgen-independent state. Thus, c-Met signaling is utilized for survival and growth under the androgen-depleted condition.

Serum hepatocyte growth factor activator (HGFA) in benign prostatic hyperplasia and prostate cancer

OBJECTIVES

Hepatocyte growth factor activator (HGFA) is responsible for proteolytic activation of the precursor form of hepatocyte growth factor (HGF). We attempted to clarify whether serum levels of HGFA could be used as a marker for prostate cancer.

MATERIAL AND METHODS

Serum levels of total HGF and HGFA were measured by enzyme-linked immunosorbent assay in 99 healthy controls, 27 patients with benign prostatic hyperplasia (BPH) and 119 patients with prostate cancer.

RESULTS

: The mean+/-S.D. serum levels of HGFA in untreated prostate cancer and BPH cases were 0.42+/-0.24 and 0.50+/-0.26 ng/ml, respectively (no significant difference). Serum HGFA was significantly elevated in hormone-refractory prostate cancer (stage D3) compared to other stages, while HGF did not significantly differ with regard to clinical stage.

CONCLUSIONS

Serum HGFA tends was elevated in patients with advanced stage prostate cancer. Further studies in large groups of patients are needed to clarify the clinical value of HGFA.

Serum hepatocyte growth factor activator inhibitor type I (HAI-I) and type 2 (HAI-2) in prostate cancer

BACKGROUND

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) and type 2 (HAI-2) are Kunitz-type serine protease inhibitors for hepatocyte growth factor activator (HGFA). We attempted to clarify whether serum levels of HAI-1 and HAI-2 could be a useful marker in patients with prostate cancer.

METHODS

Serum levels of HAI-1 and HAI-2 were measured by enzyme-linked immunosorbent assay in 27 patients with benign prostatic hyperplasia (BPH) and 118 patients with prostate cancer.

RESULTS

The mean serum levels of HAI-1 in patients with prostate cancer were significantly higher than those in patients with BPH. Furthermore, the serum HAI-1 levels in patients with distant metastasis and hormone resistant prostate cancer were significantly elevated compared with those in patients with organ-confined diseases. There were no significant differences in serum HAI-2 levels among prostate cancer subgroups according to clinical stage. Significantly elevated levels of HAI-1 were detected in 38 patients with prostate cancer before any treatment.

CONCLUSIONS

HAI-1 may be a potential tumor marker for prostate cancer. Further studies in large groups of patients are needed to define the clinical value of HAI-1.

Hepatocyte growth factor promotes cancer cell migration and angiogenic factors expression: a prognostic marker of human esophageal squamous cell carcinomas

PURPOSE

Hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, c-Met, play important roles in tumor development and progression. In this study, we measured the serum HGF levels in patients with esophageal squamous cell carcinoma (ESCC) to evaluate its relationships with clinicopathologic features and the role of HGF in ESCC.

EXPERIMENTAL DESIGN

One hundred and forty-nine patients with ESCC were studied. Pretherapy serum was collected and ELISA was used to detect the concentrations of HGF, vascular endothelial growth factor (VEGF), and interleukin 8 (IL-8). The function of HGF was shown by invasion chamber assay.

RESULTS

Pretherapy serum HGF was found to be significantly higher in patients with ESCC than in control subjects. The levels of HGF correlated significantly with advanced tumor metastasis stage and survival. Multivariate analyses showed that serum HGF level in cell migration was an independent prognostic factor. Increased HGF serum levels correlated positively with serum levels of VEGF and IL-8. Our results also showed that HGF was overexpressed in ESCC tissues and cell lines. In vitro study showed that HGF could stimulate ESCC cell to express VEGF and IL-8 and markedly enhance invasion and migration of ESCC cells. Furthermore, HGF-induced IL-8 and VEGF expression was dependent on extracellular signal-regulated kinase signaling pathways. The inhibition of extracellular signal-regulated kinase activation reduced HGF-mediated IL-8 and VEGF expression.

CONCLUSIONS

Our results suggest that serum HGF may be a useful biomarker of tumor progression and a valuable independent prognostic factor in patients with ESCC. HGF may be involved in the progression of ESCC as an autocrine/paracrine factor via enhancing angiogenesis and tumor cell invasion and migration.

Microarray analysis of prostate cancer progression to reduced androgen dependence: studies in unique models contrasts early and late molecular events

Three unique variants of the CWR22 human prostate cancer xenograft model (CWR22LD1, LD2, and LD3) with a decrease in dependence on androgens were selected under noncastrate conditions, i.e., by outgrowth after transplantation into male NCR (AT) nu mice without testosterone supplementation. These variants were unable to grow in castrated male mice. For comparison, a second set of variants with even less dependence on androgens (castrate-resistant) were derived following outgrowth from CWR22 (CWR22Rv1 and RC) or CWRLD1 (CWR22RS) after transplantion in castrated male mice. The androgen receptor (AR) gene in the CWR22LD variants was transcriptionally active and was neither mutated nor significantly overexpressed compared to CWR22. Oligonucleotide microarray analysis showed distinctly different profiles of dysregulated gene expression among the CWR22LD variants. Groups of only 26-41 genes were dysregulated greater than threefold with a different proportion of up versus downregulated genes in each variant. Only one of the castrate-resistant variants (CWR22Rv1) had a highly overexpressed AR gene but AR in this variant and the two other castrate-resistant variants, CWR22 RS and RC, was not mutated beyond that seen in CWR22. In contrast to the CWR22LD variants, a total of 342, 295, and 222 genes were dysregulated at least threefold in CWR22Rv1, CWR22RS, and CWR22RC, respectively, differing as well in the proportion of up versus downregulated genes. Many of the genes dysregulated in CWR22LD1, LD2, and LD3 were further dysregulated in CWR22Rv1, RC, or RS. The most downregulated gene was microseminoprotein beta (MSPB). Along with cyclin D1, the most upregulated gene by an order of magnitude compared to other upregulated genes was hepatocyte growth factor (HGF) (scatter factor). These results suggest that the onset in the loss of androgen dependence in CWR22 proceeds through multiple pathways and does not require any direct change in the status of AR. However, upregulation of other survival pathways like that involving HGF in these studies could co-activate AR signaling. The endogenous overexpression of genes regulating sterol biosynthesis also observed in castrate-resistant CWR22 variants delineated a clinically relevant, compensatory mechanism for overcoming androgen deprivation reaffirming a central role for AR signaling in this process.

Inhibition by evodiamine of hepatocyte growth factor-induced invasion and migration of tumor cells

Tumor cell motility plays a crucial role in the establishment of tumor metastasis and is affected by a variety of host-derived factors during the event. Hepatocyte growth factor (HGF) is one of these factors and stimulates tumor cell migration remarkably. We previously reported that evodiamine has a marked inhibitory activity on tumor cell invasion and migration in vitro. In this study, the effects of evodiamine on HGF-induced invasion and migration of tumor cell lines, colon 26-L5 carcinoma, B16-F10 melanoma and Lewis lung carcinoma (LLC) were examined. HGF promoted invasive activity of tumor cell lines with maximal induction of 1.8 times at 30 ng/ml for colon 26-L5 and LLC cells, and 2.0 times at 10 ng/ml for B16-F10 cells. Evodiamine inhibited the HGF-stimulated tumor cell invasion and migration in a concentration-dependent manner, and achieved complete suppression at 30 microM in all of the cell lines tested. When tumor cells were seeded on fibronectin-coated plates with evodiamine, their spreading on the plate was obviously inhibited, while their adhesiveness to fibronectin was unaffected. Evodiamine showed a marginal effect on tumor cell growth in a 24-h incubation, although it exhibited a marked inhibition in an over 48-h incubation. These results suggest that evodiamine suppressed HGF-stimulated invasion and migration of tumor cells partly through inhibition of cell spreading.

Targeting the HGF/SF receptor c-met using a hammerhead ribozyme transgene reduces in vitro invasion and migration in prostate cancer cells

BACKGROUND

Hepatocyte growth factor scatter factor (HGF/SF) elicits a number of biological activities including invasion and migration through activation of its tyrosine kinase receptor c-Met. Over expression of c-Met has been implicated in prostate cancer development and progression. This study examined the effect of a ribozyme transgene, designed to inhibit human c-Met expression, and its impact on in vitro invasion and migration in prostate cancer.

METHODS

A transgene (Met 560) consisting of U1 snRNA, hammerhead ribozyme, and antisense was cloned into a modified pZeoU1-EcoSpe vector and transfected into DU-145 cells. The effect of HGF/SF was tested on prostate cancer cells whose expression of c-Met had been blocked by way of a ribozyme transgene.

RESULTS

Met 560 stable transfectants (DU-145(+/+)) manifested a complete loss of c-Met expression at mRNA and protein levels. In contrast, control plasmid (DU-145(+/-)) and wild-type DU-145 cells (DU-145(-/-)) had similar levels of c-Met expression. HGF/SF significantly increased the in vitro invasiveness (mean 47.71 +/- SE 7.75; P < 0.01 vs. control 24.14 +/- 1.34), and migration (mean 48.44 +/- SE 3.51; P < 0.01 vs. control 22.95 +/- 1.47) of DU-145(-/-) cells, respectively. Similarly, HGF/SF also increased the invasion (62.33 +/- 6.34; P < 0.001 vs. control 24.5 +/- 2.35) and migration (46.14 +/- 2.26; P < 0.01 vs. control 21.82 +/- 1.62) of DU-145(+/-) cells. In contrast, DU-145(+/+) cells had lost its response to HGF/SF induced invasion (22.33 +/- 2.08; P > 0.05 vs. control 23.5 +/- 2.11) and migration (24.12 +/- 0.86; P > 0.05 vs. control 23.27 +/- 0.81).

CONCLUSIONS

Targeting the HGF/SF receptor by way of a hammerhead ribozyme encoding antisense to c-Met, is an effective method to reduce the invasive or migration potential in prostate cancer, and may have important therapeutic implications.

Metastatic squamous cell carcinoma cells that overexpress c-Met exhibit enhanced angiogenesis factor expression, scattering and metastasis in response to hepatocyte growth factor

We previously performed gene expression profiling in a multistep squamous cell carcinoma (SCC) progression model, and identified growth-regulated oncogene-1 (Gro-1/KC) as a factor that contributes to enhanced angiogenesis, tumorigenesis and metastasis. In the present study, we explored molecular pathways coactivated with Gro-1/KC, and identified a transcript that encodes c-Met, the receptor for hepatocyte growth factor/scatter factor (HGF). Northern, Western blot, and immunohistochemical analyses confirm that expression of c-Met mRNA and protein is increased with SCC progression. In vitro, HGF preferentially promoted scattering in the metastatic LY-1 and LY-2 lines, and enhanced angiogenesis factors Gro-1/KC and vascular endothelial growth factor (VEGF) production by all tumor cell lines. In vivo, tumor growth and lung metastasis were promoted by transfection and overexpression of HGF cDNA in metastatic LY-1 cells. Our data indicate that metastatic SCC cells that overexpress c-Met exhibit angiogenesis factor expression and enhanced scattering in response to HGF in vitro, and tumorigenesis and metastasis in response to HGF in the tumor microenvironment in vivo.

Phenotypic switch from paracrine to autocrine role of hepatocyte growth factor in an androgen-independent human prostatic carcinoma cell line, CWR22R

Support mechanisms involved in growth of androgen-independent prostate cancer are primarily unknown. Hepatocyte growth factor (HGF)/Met has been suggested to be one of them based primarily on immunohistochemical studies. We conducted a series of experiments to assess the role of the HGF/Met system in an androgen-dependent human prostate carcinoma, CWR22 and its androgen-independent derivative, CWR22R. We found that action of HGF changed from paracrine to autocrine in progression to androgen-independent state. CWR22 tumors did not express HGF but expressed Met, whereas prostate stromal cells expressed HGF at a high level. Growth of CWR22 was stimulated either by addition of HGF to the culture or by the presence of prostate stromal cells. On the other hand, CWR22R cells expressed both HGF and Met. Knockdown of Met expression by RNA interference method suppressed the growth of CWR22R cells. Our data suggest that HGF is intimately involved in growth of human prostate cancer and that progression from the androgen-dependent to the androgen-independent state is associated with an adaptive switch in support mechanism from paracrine to autocrine. Our data offer one mechanism to account for androgen-independent human cancer growth.

Enhanced invasion of hormone refractory prostate cancer cells through hepatocyte growth factor (HGF) induction of urokinase-type plasminogen activator (u-PA)

BACKGROUND

Increased expression of the hepatocyte growth factor (HGF) receptor (MET) is associated with high-grade prostatic adenocarcinoma and metastasis. However, the mechanism through which MET signaling contributes to prostate cancer (CaP) metastasis remains unclear.

METHODS

Human PC-3 CaP cells and in vivo selected, isogeneic variant cells of increasing metastatic potential (PC-3M, PC-3M-Pro4, and PC-3M-LN4) were used to investigate the effect of HGF on CaP cell growth, protease production, and invasion. Cell-free urokinase-type plasminogen activator (u-PA) expression and function following HGF treatment were analyzed by Western blot, ELISA, and casein/plasminogen zymography. In vitro invasion stimulated by HGF was measured using Matrigel-coated invasion chambers.

RESULTS

Both mRNA and functional protein for MET were detected in each of the CaP cell lines. HGF treatment (0-40 ng/ml) weakly increase proliferation, however, HGF induced soluble u-PA protein and activity 3-fold in the metastatic variant cells. HGF significantly stimulated the invasion of highly metastatic PC-3M-LN4 cells through Matrigel and treatment with specific urokinase receptor inhibitors diminished the HGF-stimulated invasion in a dose-dependent manner.

CONCLUSIONS

These results demonstrate the biological significance of u-PA up-regulation in response to HGF in highly metastatic hormone refractory CaP cells.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

The HGF/SF antagonist NK4 reverses fibroblast- and HGF-induced prostate tumor growth and angiogenesis in vivo

Our study examined the in vitro and in vivo responses of a newly discovered HGF/SF antagonist, NK4, on HGF/SF-promoted growth of human prostate cancer cells (PC-3). Nude mice were s.c. injected with either PC-3- and/or HGF/SF-producing fibroblasts (MRC5), and tumor size was measured over a 4-week period. rh-HGF/SF and/or NK4 were introduced by osmotic minipumps. An in vitro study found that NK4 significantly suppressed HGF/SF-induced invasion (HGF/SF; p < 0.01 vs. HGF/SF+NK4) and migration (HGF/SF; p < 0.05 vs. HGF/SF+NK4). Similarly, NK4 also suppressed the invasion (MRC5; p < 0.01 vs. MRC5+NK4) and migration (MRC5; p < 0.05 vs. MRC5+NK4) induced by MRC5 cells. NK4 also suppressed HGF/SF- and MRC5-induced tyrosine phosphorylation of the HGF/SF receptor Met as assessed by immunoprecipitation. Using a nude mouse model, prostate tumor volume (mm(3)) was significantly increased in both HGF/SF- (HGF/SF; p < 0.05 vs. control) and MRC5- (MRC5; p < 0.01 vs. control) treated groups compared to the control. In contrast, NK4 alone significantly reduced the growth of prostate tumors (NK4; p < 0.01 vs. control). In addition, NK4 also suppressed both HGF/SF- (HGF/SF; p < 0.01 vs. HGF/SF+NK4) and MRC5- (MRC5; p < 0.05 vs. MRC5+NK4) induced tumor growth in vivo by significantly reducing (p < 0.05) the degree of tumor angiogenesis using a recently discovered family of tumor endothelial markers (TEMs) by Q-RT-PCR analysis. In conclusion, NK4 suppresses both HGF/SF- and MRC5-induced invasion/migration of PC-3 cells in vitro. Furthermore, the HGF/SF antagonist NK4 significantly reduces prostate tumor growth in vivo by inhibiting the degree of tumor angiogenesis as determined by TEM-1 and TEM-8. Finally, our study provides evidence of the therapeutic potential of NK4 in prostate cancer development by antagonising HGF/SF-mediated events.

Identification of novel cellular targets in biliary tract cancers using global gene expression technology

Biliary tract carcinoma carries a poor prognosis, and difficulties with clinical management in patients with advanced disease are often due to frequent late-stage diagnosis, lack of serum markers, and limited information regarding biliary tumor pathogenesis. RNA-based global analyses of gene expression have led to the identification of a large number of up-regulated genes in several cancer types. We have used the recently developed Affymetrix U133A gene expression microarrays containing nearly 22,000 unique transcripts to obtain global gene expression profiles from normal biliary epithelial scrapings (n = 5), surgically resected biliary carcinomas (n = 11), and biliary cancer cell lines (n = 9). Microarray hybridization data were normalized using dCHIP (http://www.dCHIP.org) to identify differentially up-regulated genes in primary biliary cancers and biliary cancer cell lines and their expression profiles was compared to that of normal epithelial scrapings using the dCHIP software as well as Significance Analysis of Microarrays or SAM (http://www-stat.stanford.edu/ approximately tibs/SAM/). Comparison of the dCHIP and SAM datasets revealed an overlapping list of 282 genes expressed at greater than threefold levels in the cancers compared to normal epithelium (t-test P <0.1 in dCHIP, and median false discovery rate <10 in SAM). Several pathways integral to tumorigenesis were up-regulated in the biliary cancers, including proliferation and cell cycle antigens (eg, cyclins D2 and E2, cdc2/p34, and geminin), transcription factors (eg, homeobox B7 and islet-1), growth factors and growth factor receptors (eg, hepatocyte growth factor, amphiregulin, and insulin-like growth factor 1 receptor), and enzymes modulating sensitivity to chemotherapeutic agents (eg, cystathionine beta synthase, dCMP deaminase, and CTP synthase). In addition, we identified several "pathway" genes that are rapidly emerging as novel therapeutic targets in cancer (eg, cytosolic phospholipase A2, an upstream target of the cyclooxygenase pathway, and ribosomal protein S6 kinase and eukaryotic translation initiation factor 4E, two important downstream mediators of the mitogenic Akt/mTOR signaling pathway). Overexpression of selected up-regulated genes was confirmed in tissue microarrays of biliary cancers by immunohistochemical analysis (n = 4) or in situ hybridization (n = 1), and in biliary cancer cell lines by reverse transcriptase PCR (n = 2). The majority of genes identified in the present study has not been previously reported in biliary cancers, and represent novel potential screening and therapeutic targets of this cancer type.

High serum hepatocyte growth factor level in patients with non-Hodgkin's lymphoma

Higher pretreatment serum hepatocyte growth factor (HGF) levels were observed in patients with multiple myeloma and Hodgkin's disease, but not in those with non-Hodgkin's lymphoma (NHL). We examined patients' serum levels at diagnosis using enzyme-linked immunosorbent assay and histological expression of HGF in pathological specimens of lymphoma, in relation to clinical features. The subjects were 77 NHL patients and 40 healthy controls. The serum levels of HGF in NHL patients at diagnosis were significantly higher than those in healthy controls (median 1019 vs. 689 pg/mL, P < 0.001). At diagnosis, patients with more than two sites of extranodal involvement (P = 0.001), higher scores of international prognostic index (P = 0.015), and advanced Ann Arbor stage (P = 0.023) had a higher level of serum HGF. Although the association of pretreatment serum HGF level and survival was not significant, a correlation of serial change of serum HGF levels with treatment response was found in limited cases. Furthermore, HGF expression of lymphoma tissues was shown in 18 of 24 (75%) different NHL subtypes, including most of the diffuse large B cell lymphoma (12 of 15, 80%). In conclusion, our study showed higher pretreatment serum HGF levels in NHL patients, which was related to clinical features; and the serial change of HGF seemed to parallel the treatment response. The pathogenic role of HGF in NHL patients was further highlighted by a modest expression of HGF in most of the diffuse large B cell lymphoma.

Hepatocyte growth factor: from diagnosis to clinical applications

Hepatocyte growth factor (HGF), initially identified and molecularly cloned as a potent mitogen of primary cultured hepatocytes, has multiple activities in a variety of tissues during the course of development and also in various disease states. HGF plays key roles in the attenuation of disease progression as an intrinsic repair factor. It is also evident that HGF levels are regulated under different conditions, for example, during the course of pregnancy, aging, and disease. This review focuses on the levels of HGF in normal and pathophysiological situations and examines the relationships between HGF levels and disease, disease stage, and disease prognosis. The clinical potential of HGF as a treatment for subjects with various diseases is also given attention.