Hepatocyte growth factor activation inhibitors - therapeutic potential in cancer

Hepatocyte growth factor (HGF) plays a plethora of roles in the progression of many invasive and metastatic cancers. The interaction between tumour cells and their surrounding stromal environment remains a crucial factor governing tumour invasion and metastasis. HGF is primarily synthesised by stromal fibroblasts as an inactive precursor known as pro-HGF. A number of proteases have demonstrated the ability to convert pro-HGF into the biologically active form of HGF, although the two main factors responsible are HGF activator (HGFA) and matriptase. The HGF activation inhibitors (HAI-1 and HAI-2) are two novel Kunitz-type serine protease inhibitors that regulate HGFA and matriptase activity to govern the influence of HGF within the body. Deregulation of HAI expression can lead to shift in the HGF activation/inhibition balance ratio in favour of enhanced HGF production. Therefore, these HGF activation inhibitors may have a direct bearing on cancer invasion and metastasis. This review examines the accumulating evidence on the emerging role and therapeutic potential of HAI-1 and HAI-2 in cancer.

The transcript expression and protein distribution pattern in human colorectal carcinoma reveal a pivotal role of COM-1/p8 as a tumour suppressor

BACKGROUND AND AIMS

COM-1(P8) is thought to play a role in the formation of metastases. This appears from current evidence to be different in various types of solid tumours. We aimed to examine the role COM-1 played in the development of colorectal cancer.

MATERIALS AND METHODS

The expression of COM-1 mRNA was examined using a quantitative polymerase chain reaction (PCR) technique together with immunohistochemistry to examine expression and distribution of the COM-1 protein in human colorectal carcinoma and matched normal colorectal mucosa.

RESULTS

COM-1 was expressed in 22.8% of normal colorectal mucosa samples and the expression in these tissues was 54.9 copies of COM-1 transcript per sample. In tumour tissues, 43.6% of samples expressed COM-1, at a level of 98.9 copies of COM-1 transcript per sample (p=0.012). Normal tissues demonstrated strong nuclear and peri-nuclear staining for COM-1 on immunohistochemistry (IHC) and in tumour tissues, the level of staining was found to be much greater, with a greater degree of cytoplasmic staining and little nuclear staining. Early-stage tumours showed a greater degree of staining on IHC compared to those at an advanced stage of disease.

CONCLUSION

COM-1, although overexpressed at the messenger level, appears to be distributed in a cytoplasmic fashion at the protein level in tumours. Tumours at advanced stage express COM-1 protein to a lesser extent than their early-stage counterparts.

Vascular endothelial growth inhibitor, expression in human prostate cancer tissue and the impact on adhesion and migration of prostate cancer cells in vitro

Vascular endothelial growth inhibitor (VEGI) has been associated with tumour-related vasculature in certain maligancies. However, its implication in prostate cancer remains unknown. We investigated the expression pattern and role of VEGI in prostate cancer and prostate cancer cells. The expression of VEGI was examined in human prostate tissue and prostate cancer cell lines. The biological impact of modifying the expression of VEGI in prostate cancer cells was evaluated using in vitro models. VEGI mRNA was expressed in a wide variety of human prostate cancer cell lines and most prostate specimens. VEGI protein was seen in normal prostate epithelium, but was decreased or absent in prostate cancer specimens, particularly in tumours with high Gleason scores. Moreover, forced-expression of VEGI led to a decrease in the motility and adhesion of prostate cancer cells in vitro. In contrast, knocking down VEGI in the cells resulted in an increase in motility and adhesion. Interestingly, both forced-expression and knocking down of VEGI had no bearing on growth and invasive capacity of prostate cells. In conclusion, the expression of VEGI is decreased in prostate cancer and is almost absent in tumours with high Gleason scores. Together with its inhibitory effect on cellular motility and adhesion, this suggests that VEGI functions as a negative regulator for aggressiveness during the development and progression of prostate cancer.

Expression of vascular endothelial growth inhibitor (VEGI) in human urothelial cancer of the bladder and its effects on the adhesion and migration of bladder cancer cells in vitro

BACKGROUND

Vascular endothelial growth inhibitor (VEGI) has been implicated in the regulation of tumour-related vasculature in certain solid tumours. However, its role in urothelial tumours is still unclear. In the present study, the role played by VEGI in urothelial tumours of the bladder was investigated.

MATERIALS AND METHODS

The expression of VEGI was examined in cancer human bladder tissues and in a serial of cell lines using immunochemical staining and RT-PCR respectively. The biological impact of modifying VEGI expression in urothelial cancer cells was evaluated using in vitro models.

RESULTS

VEGI mRNA was expressed in a wide variety of human cell lines. VEGI expression was seen in normal urothelial and stromal cells, but was found to be reduced or absent in urothelial cancer cells. The positive staining in normal tissue (6/7) was significantly higher than that of urothelial cancer tissues (2/12), p=0.006. Moreover, overexpression of VEGI reduced the motility and adhesion of urothelial cancer cells in vitro. However, the overexpression of VEGI had no bearing on the growth and invasion of urothelial cancer cells.

CONCLUSION

VEGI has an inhibitory effect on cellular motility and adhesion in bladder cancer cells. Taken together with the expression pattern of VEGI in urothelial cancer of the bladder, it suggests that VEGI functions as a negative regulator of aggressiveness during development and progression of bladder cancer.

Vascular endothelial growth inhibitor in human cancer (Review)

Vascular endothelial growth inhibitor (VEGI), also known as tumour necrosis factor superfamily member 15 (TNFSF15) and TNF ligand related molecule 1 (TL1), is a recently identified anti-angiogenic cytokine that belongs to the TNF superfamily. Three isoforms of VEGI, VEGI 174, 192, and 251 have been documented, all sharing 151 common C-terminal amino acids but differing in their N-terminal regions. The investigations into the biological functions of VEGI have pointed to a potential cancer inhibitory role for the cytokine. The inhibitory effects of VEGI on cancer are manifested in three main areas, the direct effect on cancer cells, the anti-angiogenic effects on endothelial cells, and stimulation of maturation of dendric cells. The clinical aspect of VEGI in cancer is also being explored in recent years. The present article overviews the recent progress on this molecule and discusses the value of VEGI as a potential therapeutic target in cancer therapy.

Effect of expressional alteration of KAI1 on breast cancer cell growth, adhesion, migration and invasion

KAI1, also known as CD82, is a candidate metastasis suppressor gene and has been indicated in the disease progression of certain solid tumours, including those of breast cancer. The present study aimed to investigate the importance of KAI1 as a potential metastasis suppressor in breast cancer cells. MDA-MB-231 and MCF-7 sublines with different patterns of KAI1 expression were created by way of anti-KAI1 transgene or transfection of KAI1 expression construct. Cell adhesion was markedly increased in cancer cells showing increased expression of KAI1 (MCF-7(KAI1EXP), p=0.021 vs. control cells), while it was significantly reduced in the KAI1 knockout subline, MDA-MB-231(KAI1KO) (p=0.002 and 0.0004, respectively). Significant increase of cell migration of MCF-7(KAI1EXP) cells (p=0.024 vs. control) and restricted motility of MDA-MB-231(KAI1KO) cells (p=0.003) were observed. Furthermore, MCF-7(KAI1EXP) cells also showed reduced cell invasion (p=0.022), while MDA-MB-231(KAI1KO) cell line showed a significant increase in invasion (p=0.0063 and p=0.007, respectively). KAI1 did not affect cell growth. It is concluded therefore that KAI1 plays an important role in cell adhesion, invasion and migration of breast cancer cells, in vitro, and is a potential metastasis suppressor gene in breast cancer.

WAVE3 is associated with invasiveness in prostate cancer cells

INTRODUCTION

Wiskott-Aldrich syndrome verprolin-homologous 3 (WAVE3) belongs to Wiskott-Aldrich syndrome family proteins (WASP), which, along with other members, play a critical role in the regulation of actin polymerization and cell motility. We investigated the expression pattern and the effects of manipulating endogenous WAVE3 expression in prostate cancer cells.

MATERIALS AND METHODS

Reverse transcriptase-polymerase chain reaction (RT-PCR) of prostate cell lines and immunohistochemical staining of normal and cancer specimens for WAVE3 proteins were done. WAVE3 knockdown clones were synthesized using hammerhead ribozyme transgenes and transfected by electroporation into DU-145 and PC-3 cells. The impact of WAVE3 knockdown was studied using in vitro functional assays.

RESULTS

RT-PCR for WAVE3 showed strong expression in both PC-3 and DU-145 cell lines. Immunohistochemistry of prostate tissue specimens showed that the cytoplasm of cancer cells had stronger staining than normal epithelium. The mean [(+/-standard error of mean (SEM)] invading cell number for PC-3(DeltaW3R1) and PC-3(DeltaW3R2) was 5.06 (+/-0.42) and 6.33 (+/-0.19), respectively, compared with PC-3(WT) (12.27 +/- 0.42; P < 0.001). Similarly, the mean (+/-SEM) invading cell numbers for DU-145(DeltaW3R1) and DU-145(DeltaW3R2) were 10.80 (+/-1.33) and 10.20 (+/-0.86) compared with DU-145(WT) (14.80 +/- 0.24, P < 0.05). No significant differences were observed in the adhesiveness and proliferation between the knockdown mutants and the wild types.

CONCLUSIONS

This is the first report on the expression patterns and the functions of WAVE3 in prostate cancer cell lines. This study shows that WAVE3 is pivotal in controlling the invasiveness of prostate cancer cells. Further work is needed to assess WAVE3 as a potential marker for predicting tumor aggressiveness.

KAI-1/CD82, the molecule and clinical implication in cancer and cancer metastasis

CD82, also known as KAI-1, structurally belongs to tetraspanin family while categorised as metastasis suppressor gene on functional grounds. KAI1/CD82 is localized on cell membrane and form interactions with other tetraspanins, integrins and chemokines which are respectively responsible for cell migration, adhesion and signalling. In recent years apart from its significant involvement in the suppression of secondary tumours it has also been observed that KAI1/CD82 plays a vital role in virus binding and its entry inside the cell. Decreased expression of KAI1/CD82 molecule results in aggravating cancer progression. Altered expression levels of KAI1/CD82 molecule in different types of human cancer have been implicated as having prognostic value and linking to the long term survival of the patients. Increased level of KAI1/CD82 also results in the suppression of secondary tumour growth. Increased expression of this molecule results in reduced cell invasion and cell migration due to endocytosis of epidermal growth factor receptors (EGFR). Thus, KAI-1/CD82 is a pivotal molecule in the regulation of cancer cells' behaviour and has important clinical and therapeutic implications in cancer.

Transcriptional and translational modulation of KAI1 expression in ductal carcinoma of the breast and the prognostic significance

KAI1, also known as CD82, has been shown to have a potential impact on the invasiveness of cancer cells. In the present study, expression pattern of KAI1, both at transcription and translation levels and the potential clinical value of the expression were explored in a cohort of normal and ductal mammary cancer tissues (n=71). A marked reduction of KAI1 transcript was observed in invasive ductal breast tumours as compared to normal tissues. Expression of KAI1 protein was higher in normal tissues as compared to tumour samples. Though no significant difference of KAI1 expression between different grades of tumour was observed (p=0.064), significant correlation of TNM staging with KAI1 expression has been observed in invasive ductal breast cancer patients (p=0.045). Additionally, it was also observed that patients showing higher expression of KAI1 had a longer 10-year survival rate as compared to a low level or completely negative expression KAI1 (p=0.0136). KAI1 inverse correlation with tumour progression may be used as a strong prognostic marker.

WAVE1 is associated with invasiveness and growth of prostate cancer cells

PURPOSE

WAVE1 belongs to the Wiskott-Aldrich syndrome family of proteins, which have an integral part in cell motility, a crucial step in cancer metastasis. We investigated the expression pattern and the effects of manipulating endogenous WAVE1 expression in prostate cancer cells.

MATERIALS AND METHODS

WAVE1 protein expression in normal and cancer specimens, and in prostate cell lines was assessed using immunohistochemistry and reverse transcriptase-polymerase chain reaction, respectively. Hammerhead ribozyme transgenes were synthesized and cloned into the mammalian expression vector pEF6/V5-His TOPO TA, and transfected by electroporation into PC-3(DeltaW1R1/2) and DU-145(DeltaW1R1/2) cell lines. In vitro invasion, adhesion and growth assays were used to assess the impact of WAVE1 knockdown.

RESULTS

Immunohistochemistry of prostate tissue specimens showed that the cytoplasm of cancer cells had stronger staining than normal epithelium. Reverse transcriptase-polymerase chain reaction for WAVE1 showed strong expression in the PC-3 (European Collection of Cell Cultures, Salisbury, United Kingdom) and DU-145 (ATCC(R)) cell lines. WAVE1 knockdown was associated with a significant decrease in invasion but not in adhesion. The mean +/- SEM number of invading PC-3(DeltaW1R1) and PC-3(DeltaW1R2) cells was 7.27 +/- 0.38 and 6 +/- 0.29, respectively, compared to 12.27 +/- 0.42 PC-3(WT) cells (p <0.001). Similarly the mean number of invading DU-145(DeltaW1R1) and DU-145(DeltaW1R2) cells was 9.20 +/- 0.70 and 11.60 +/- 0.84 compared to 14.80 +/- 0.24 DU-145(WT) cells (p <0.001).

CONCLUSIONS

To our knowledge this is the first report of the expression pattern of WAVE1 in prostate cancer cell lines and tissues, and the functional impact of WAVE1 knockdown. Further investigations to assess WAVE1 as a potential target for anti-metastasis therapy must be explored.

Suppression of hepatocyte growth factor activator inhibitor-1 leads to a more aggressive phenotype of prostate cancer cells in vitro

The hepatocyte growth factor (HGF) pathway has been well documented as playing a vital role in the progression and development of many different types of human cancers; as such this pathway is usually tightly regulated. In cancer cells, the regulation of this pathway has been shown to be disrupted, allowing an increase in activation of pro-HGF to active HGF. There are a number of molecules capable of activating pro-HGF, such as matriptase-1, a type II transmembrane serine protease, or hepatocyte growth factor activator, and in turn, these are also subject to regulation. In the current study we examined the importance of hepatocyte growth factor activator inhibitor-1 (HAI-1) which is known to inhibit a number of HGF-activating molecules. We reduced the expression of this molecule in both PC-3 and DU-145 cell lines using hammerhead ribozyme technology, and we examined various important characteristics associated with cancer progression and development in vitro. Prostate cancer cells, after loss of HAI-1, had a significantly increased in vitro invasiveness together with an increase in cellular motility. Notably, loss of HAI-1 resulted in a slower rate of cell growth over a prolonged period (5 days). This in vitro evidence collectively suggests that the suppression of HAI-1 expression gives rise to a more aggressive cancer cell phenotype. This implies that therapies inducing the overexpression of HAI-1 or delivering an exogenous source of HAI-1 protein may hold potential as a treatment to slow the progression of prostate cancer.

Matriptase-2 Inhibits Breast Tumor Growth and Invasion and Correlates with Favorable Prognosis for Breast Cancer Patients

PURPOSE

The type II transmembrane serine proteases are cell surface proteolytic enzymes that mediate a diverse range of cellular functions, including tumor invasion and metastasis. Matriptase (matriptase-1) and matriptase-2 belong to the type II transmembrane serine protease family. Matriptase-1 is known to play a role in breast cancer progression, and elevated levels of matriptase-1 correlate with poor patient outcome. The role of matriptase-2 and its cellular function in cancer is unknown. This study aimed to provide new insights into the significance of matriptase-2 in cancer.

EXPERIMENTAL DESIGN

Matriptase-2 expression levels were assessed in a cohort of human breast cancer specimens (normal, n = 34; cancer, n = 95), in association with patient clinical variables, using both quantitative and qualitative analysis of the matriptase-2 transcript along with immunohistochemical techniques. Matriptase-2 was also experimentally overexpressed in the MDA-MB-231 human breast cancer cell line. The effects of matriptase-2 overexpression were examined through a series of in vitro and in vivo studies.

RESULTS

Here, we show that reduced matriptase-2 levels in breast cancer tissues correlate with an overall poor prognosis for the breast cancer patient. This study also reveals that matriptase-2 overexpression in breast cancer cells significantly suppressed tumorigenesis in CD1 athymic mice (P = 0.000003). Furthermore, we report that matriptase-2 overexpression dramatically reduced the invasive (P = 0.0001) and migratory properties (P = 0.01) of the breast cancer cells.

CONCLUSIONS

Matriptase-2 suppresses breast tumor development in vivo, displays prognostic value for breast cancer patients, inhibits both breast cancer cell invasion and motility in vitro, and may play a contrasting role to matriptase-1 in breast cancer.

Hepatocyte growth factor up-regulates the expression of the bone morphogenetic protein (BMP) receptors, BMPR-IB and BMPR-II, in human prostate cancer cells

Hepatocyte growth factor (HGF) plays multiple roles in cancer, by acting as a motility, invasion and angiogenesis stimulating factor, which promotes metastasis and tumour growth. Bone morphogenetic proteins (BMPs) are members of the TGF-beta superfamily. The effects of BMPs are mediated by two subgroups of receptors, type I and type II. Recent studies have shown that some BMPs, via their signaling pathways, affect the growth of prostate cancer cells. BMPR-IB and BMPR-II have been reported to be expressed at low levels in prostate cancer. However, little is known about the crosstalk between HGF and BMP pathways. In this study, prostate cancer cells (PC-3 and DU-145) were exposed to HGF at different concentrations (1-75 ng/ml) for 18 h, or were treated with HGF at 40 ng/ml over various time periods (up to 24 h). The effect of HGF on BMP receptor expression was further investigated in a nude mouse PC-3 xenograft model. Mice were treated with either HGF, the HGF antagonist NK4, or a combination of both. The expression of BMPR-IB and BMPR-II mRNA was up-regulated by HGF, as shown by both conventional PCR and quantitative PCR. An elevation of BMPR-IB and BMPR-II at the protein level was confirmed by both Western blot analysis and immunocytochemical staining. In a murine prostate tumour model, infusion of recombinant HGF resulted in an increase in the levels of both BMPR-IB and BMPR-II transcript in prostate tumours. Concomitant delivery of NK4, an HGF antagonist, prevented this effect. In conclusion, HGF up-regulates the expression of the bone morphogenetic protein receptors, BMPR-IB and BMPR-II, in prostate cancer cells, both in vitro and in vivo. This may have important implications in the development of bone metastasis in prostate cancer.

Genetic reduction of matriptase-1 expression is associated with a reduction in the aggressive phenotype of prostate cancer cells in vitro and in vivo

PURPOSE

Matriptase-1 has been implicated as playing an important role in various types of cancer progression through many different cancer related pathways. In the current study we assessed the efficacy of targeting matriptase-1 using ribozyme technology in vitro and in vivo.

EXPERIMENTAL DESIGN

Matriptase-1 expression was reduced in the PC-3 and DU-145 cell line using hammerhead ribozyme transgenes. In vitro assays were set up to assess changes in growth, invasion, adhesion and migration in these cells. In vivo tumour development model was also used to examine the efficacy of targeting matriptase-1 in a living environment.

RESULTS

The in vitro results suggest an overall reduction in the aggressive nature of the two cell lines (PC-3 and DU-145) when matriptase-1 levels are reduced, with properties such as growth, invasiveness and migration all being reduced (in most cases a greater than 50% reduction in migration and invasion compared to the control was observed), though strangely an increase in adhesion is seen in the PC-3 knockout. The in vitro data is strongly backed up by the results of the in vivo work which demonstrates matriptase-1 deficient cells have a substantially reduced ability to grow and develop in vivo compared to control cells when explanted into nude mice, with significant differences in growth and development (P < or = 0.05) being seen after 7 days, and highly significant differences (p < or = 0.001) after 15 days.

CONCLUSIONS

Together this data strongly implicates matriptase-1 as playing a vital role in the aggressive nature and progression of prostate cancer.

Applicability of an image analysis system in alveolar bone loss measurement

Clinical and epidemiological studies in the field of periodontics and endodontics often utilize radiographs to monitor or measure the changes in bone structure and density. Periodontal bone loss or gain can be quantified on a radiograph by measurement of the distance between the bottom of the bony pocket and the apical contour of the involved tooth. The objective of this investigation was to study the accuracy of an image analysis system (IAS) to measure changes in height of the interproximal crest on radiographs. Artificial bone lesions were introduced in a dissectioned part of a human mandible. The distances between crest and apices were measured with a micrometer (MM). Radiographs were produced with horizontal and vertical deviations of 10 degrees. The radiographs were digitized and processed by computer. The landmarks in the digital image were enhanced mathematically and by histogram-based thresholding. The depth of the introduced defect was increased 6 times, followed by the measurement procedure. The IAS produced measurements of crown-apex distances with an accuracy of 0.066 to 0.358 mm. Repeated crest height measurements were recorded with an accuracy of 0.112 to 0.184 mm. Both the histogram-based binarization and the ellipse-fitting type of contour detection could be applied precisely. Misangulation errors during radiographic exposure of 10 horizontal or vertical did not statistically significant influence the IAS-measurements. The IAS can be applied in clinical trials and follow-up studies.

A computer-aided image analysis system for area measurement of tooth root surfaces

The characteristics of a computer-aided Image Analysis System (IAS) to conduct linear and area measurements on tooth root surfaces were investigated. The borders of the features to be measured were extracted from a digitized video image by histogram-based thresholding and binarization. The lengths and square areas were expressed in the number of pixels. The reference-length and area of one pixel were obtained through measurement of the diameter of a metal ball of known diameter in the same digital image. The validity of the IAS was tested using radiographs of teeth containing round metal restorations of known diameter and area. The accuracy of the length measurements ranged from -2.0 to 2.1%, whereas the accuracy of area measurement was between -5.3 and 0.8%. The precision of the IAS to identify the borders of a tooth root surface and to reproducibly calculate its area, expressed in a coefficient of variation, ranges from 0.49 to 4.11%. The results indicate that imaging techniques can be applied to obtain very accurate measurements of tooth root surfaces.