HGF and ligation of alphavbeta5 integrin induce a novel, cancer cell-specific gene expression required for cell scattering

Advance in vasculogenic mimicry in ovarian cancer (Review)

Ovarian cancer (OC) is a common and highly prevalent malignant tumor in women, associated with a high mortality rate, easy recurrence and easy metastasis, which is predominantly at an advanced stage when detected in patients. This renders the cancer more difficult to treat, and consequently it is also associated with a low survival rate, being the malignancy with the highest mortality rate among the various gynecological tumors. As an important factor affecting the development and metastasis of OC, understanding the underlying mechanism(s) through which it is formed and developed is crucial in terms of its treatment. At present, the therapeutic methods of angiogenic mimicry for OC remain in the preliminary stages of exploration and have not been applied in actual clinical practice. In the present review, various signaling pathways and factors affecting angiogenic mimicry in OC were described, and the chemical synthetic drugs, natural compound extracts, small-molecule protein antibodies and their associated targets, and so on, that target angiogenic mimicry in the treatment of OC, were discussed. The purpose of this review was to provide new research ideas and potential theoretical support for the discovery of novel therapeutic targets for OC that may be applied in the clinic, with the aim of effectively reducing its metastasis and recurrence rates.

Integrins Within the Tumor Microenvironment: Biological Functions, Importance for Molecular Targeting, and Cancer Therapeutics Innovation

Many cellular functions important for solid tumor initiation and progression are mediated by members of the integrin family, a diverse family of cell attachment receptors. With recent studies emphasizing the role of the tumor microenvironment (TME) in tumor initiation and progression, it is not surprising that considerable attention is being paid to integrins. Several integrin antagonists are under clinical trials, with many demonstrating promising activity in patients with different cancers. A deeper knowledge of the functions of integrins within the TME is still required and might lead to better inhibitors being discovered. Integrin expression is commonly dysregulated in many tumors with integrins playing key roles in signaling as well as promotion of tumor cell invasion and migration. Integrins also play a major role in adhesion of circulating tumor cells to new sites and the resulting formation of secondary tumors. Furthermore, integrins have demonstrated the ability to promoting stem cell-like properties in tumor cells as well as drug resistance. Anti-integrin therapies rely heavily on the doses or concentrations used as these determine whether the drugs act as antagonists or as integrin agonists. This expert review offers the latest synthesis in terms of the current knowledge of integrins functions within the TME and as potential molecular targets for cancer therapeutics innovation.

A bioinformatics approach to identify novel long, non-coding RNAs in breast cancer cell lines from an existing RNA-sequencing dataset

Breast cancer research has traditionally centred on genomic alterations, hormone receptor status and changes in cancer-related proteins to provide new avenues for targeted therapies. Due to advances in next generation sequencing technologies, there has been the emergence of long, non-coding RNAs (lncRNAs) as regulators of normal cellular events, with links to various disease states, including breast cancer. Here we describe our bioinformatic analyses of a previously published RNA sequencing (RNA-seq) dataset to identify lncRNAs with altered expression levels in a subset of breast cancer cell lines. Using a previously published RNA-seq dataset of 675 cancer cell lines, a subset of 18 cell lines was selected for our analyses that included 16 breast cancer lines, one ductal carcinoma in situ line and one normal-like breast epithelial cell line. Principal component analysis demonstrated correlation with well-established categorisation methods of breast cancer (i.e. luminal A/B, HER2 enriched and basal-like A/B). Through detailed comparison of differentially expressed lncRNAs in each breast cancer sub-type with normal-like breast epithelial cells, we identified 15 lncRNAs with consistently altered expression, including three uncharacterised lncRNAs. Utilising data from The Cancer Genome Atlas (TCGA) and The Genotype Tissue Expression (GETx) project via Gene Expression Profiling Interactive Analysis (GEPIA2), we assessed clinical relevance of several identified lncRNAs with invasive breast cancer. Lastly, we determined the relative expression level of six lncRNAs across a spectrum of breast cancer cell lines to experimentally confirm the findings of our bioinformatic analyses. Overall, we show that the use of existing RNA-seq datasets, if re-analysed with modern bioinformatic tools, can provide a valuable resource to identify lncRNAs that could have important biological roles in oncogenesis and tumour progression.

T-DM1-resistant cells gain high invasive activity via EGFR and integrin cooperated pathways

Ado-trastuzumab emtansine (Kadcyla®; T-DM1) is an antibody-drug conjugate developed to treat trastuzumab-resistant disease. Despite initial favorable outcomes, most patients eventually cease to respond due to developing acquired resistance to T-DM1. Currently, there is no targeted therapy to treat T-DM1-resistant disease. To explore novel therapeutic targets to improve therapeutic efficacy of T-DM1, we generated T-DM1-resistant cells using trastuzumab-resistant JIMT1 cells. We found that the loss of human epidermal growth factor receptor 2 confers T-DM1 resistance, which in turn activates a compensatory mechanism that increases epidermal growth factor receptor (EGFR) expression. Upregulation of EGFR increases the protein levels of α5β1 and αVβ3 integrins, resulting in enhanced motility and invasion of T-DM1-resistant cells. This study delineates previously unappreciated relationships between α5β1 and αVβ3 and suggests that specific integrins should be carefully selected as therapeutic targets to treat T-DM1-resistant disease. Specifically, silencing β1 integrin expression by siRNA in T-DM1-resistant cells destabilizes α5, but increases expression of αV, a critical integrin mediating the invasion and metastases in many different cancers. As a consequence, T-DM1-resistant cells gain metastatic potential and become more invasive. This finding is underscored by the fact that β1 integrin blockage induced by an inhibitory antibody, MAB 13, significantly increases invasion of T-DM1-resistant cells. However, the increased cell invasion induced by β1 integrin blockage can be significantly reduced by either EGFR inhibitor or specific siRNA against αV integrin. The discovery of functional cooperation between EGFR and αV integrin in regulating cell growth and invasion provides an opportunity to develop novel therapeutic strategy by dual-targeting EGFR and specific integrin to overcome T-DM1 resistance.

Migration-inducing gene-7 independently predicts poor prognosis of human osteosarcoma and is associated with vasculogenic mimicry

Vasculogenic mimicry (VM) is a special type of vascular channel formed by tumor cells without endothelial cell participation. Migration-inducing gene 7 (MIG-7) plays an important role in regulating VM. In this study, immunohistochemical staining was used to detect MIG-7 in tissue specimens from 141 primary osteosarcoma patients, and the relationship between MIG-7 and VM was examined. Survival analysis were performed to evaluate the prognoses. MIG-7 knockdown osteosarcoma cells were used for cell proliferation, apoptosis, migration, invasiveness and VM formation assays. A spontaneously metastasizing cell line-derived orthotopic xenograft mouse model was established to evaluate the effect of MIG-7 knockdown on tumorigenesis, VM formation and lung metastasis. MIG-7 expression was associated with VM formation. There were significant differences in overall and metastasis-free survival between the MIG-7-positive and MIG-7-negative groups. The MIG-7 expression was shown to be an independent indicator of both overall and metastasis-free survival. In vitro knockdown of MIG-7 dramatically reduced migration, invasion and VM formation in osteosarcoma cells without any significant effect on cell proliferation and apoptosis. MIG-7 knockdown also exhibited potent antitumor, antimetastasis and anti-VM effects in the orthotopic mouse model of 143B osteosarcoma. Therefore, MIG-7 serves as an independent unfavorable prognostic indicator in osteosarcoma patients and MIG-7 is an important mediator of osteosarcoma VM formation.

Migration-inducing gene 7 promotes tumorigenesis and angiogenesis and independently predicts poor prognosis of epithelial ovarian cancer

Epithelial ovarian carcinomas (EOC) cause more mortality than any other cancer of the female reproductive system. New therapeutic approaches to reduce EOC mortality have been largely unsuccessful due to the poor understanding of the mechanisms underlying EOC proliferation and metastasis. Progress in EOC treatment is further hampered by a lack of reliable prognostic biomarkers for early risk assessment. In this study, we identify that Migration-Inducting Gene 7 (MIG-7) is specifically induced in human EOC tissues but not normal ovaries or ovarian cyst. Ovarian MIG-7 expression strongly correlated with EOC progression. Elevated MIG-7 level at the time of primary cytoreductive surgery was a strong and independent predictor of poor survival of EOC patients. Cell and murine xenograft models showed that MIG-7 was required for EOC proliferation and invasion, and MIG-7 enhanced EOC-associated angiogenesis by promoting the expression of vascular endothelial growth factor. Inhibiting MIG-7 by RNA interference in grafted EOC cells retarded tumor growth, angiogenesis and improved host survival, and suppressing MIG-7 expression with a small molecule inhibitor D-39 identified from the medicinal plant Liriope muscari mitigated EOC growth and invasion and specifically abrogated the expression of vascular endothelial growth factor. Our data not only reveal a critical function of MIG-7 in EOC growth and metastasis and support MIG-7 as an independent prognostic biomarker for EOC, but also demonstrate that therapeutic targeting of MIG-7 is likely beneficial in the treatment of EOC.

HGF/Met Signaling in Cancer Invasion: The Impact on Cytoskeleton Remodeling

The invasion of cancer cells into surrounding tissue and the vasculature is essential for tumor metastasis. Increasing evidence indicates that hepatocyte growth factor (HGF) induces cancer cell migration and invasion. A broad spectrum of mechanisms underlies cancer cell migration and invasion. Cytoskeletal reorganization is of central importance in the development of the phenotype of cancer cells with invasive behavior. Through their roles in cell mechanics, intracellular trafficking, and signaling, cytoskeleton proteins participate in all essential events leading to cell migration. HGF has been involved in cytoskeleton assembly and reorganization, and its role in regulating cytoskeleton dynamics is still expanding. This review summarizes our current understanding of the role of HGF in regulating cytoskeleton remodeling, distribution, and interactions.

Production, characterization, and in vitro effects of a novel monoclonal antibody against Mig-7

Development of new cancer therapies based on specific recognition of molecules in cancer cells is a significant challenge, as this requires identification of such molecules (molecular targets) and subsequent development of high-affinity, selective binders (targeting molecules). While several molecular targets for cancer therapies are currently under evaluation in clinical trials, greater selectivity for cancer cells over normal cells is required to enhance efficacy. Migration-inducing gene 7 (Mig-7), a membrane protein found in various types of carcinoma cells, is a cancer-specific biomarker and a promising molecular target for targeted cancer therapies. The purpose of this study was to produce and characterize a novel monoclonal antibody (mAb) raised against an N-terminal peptide of human Mig-7 (Mig-7(1-30)). The Mig-7(1-30) peptide was conjugated with a KLH carrier protein for immunization, and the mAb specific to Mig-7 (STmAb-1) was produced using hybridoma technology. Western blot analysis showed that STmAb-1 specifically reacted with a 23-kDa Mig-7 protein expressed in cancer cell lines, and, crucially, not with primary human fibroblasts. The affinity constant (Kaff) of STmAb-1, as measured by non-competitive enzyme immunoassay, was 1.31 × 10(9) M(-1), indicating high mAb affinity against Mig-7. Immunofluorescence assays demonstrated that STmAb-1 could specifically recognize Mig-7 expressed in cancer cell lines, but not in primary human fibroblasts and keratinocytes. Moreover, STmAb-1 inhibited the growth of MCF7 and HeLa cell lines in contrast to primary human fibroblasts, highlighting its potential usefulness in the development of new cancer therapeutics.

Recombinant viral capsid protein VP1 suppresses lung cancer metastasis by inhibiting COX-2/PGE2 and MIG-7

Recombinant capsid protein VP1 (rVP1) of foot-and-mouth disease virus binds to integrins to modulate Akt/GSK3-β signaling and suppress migration/invasion and metastasis of cancer cells, but the underlying molecular mechanism is unclear. Here, we showed that the rVP1-mediated inhibition of Akt/GSK3-β signaling and cell migration/invasion was accompanied by downregulation in phosphatidylinositol (3,4,5)-triphosphate (PIP3), integrin-linked kinase (ILK) and IKK/NF-κB signaling as well as suppression of COX-2/PGE2 and MIG-7. Addition of PIP3 or overexpression of ILK reversed the rVP1-induced inhibition of IKK/NF-κB signaling, COX-2 and MIG-7. The rVP1-mediated downregulation of COX-2/PGE2 and MIG-7 led to not only attenuation of epithelial-mesenchymal transition, MMP2 activity and invasion of lung cancer cells in vitro but also decreased tumor growth and metastasis of lung cancer in xenograft mice. Moreover, downregulation of COX-2/PGE2 and MIG-7 significantly prolonged the overall and disease-free survival of lung cancer-bearing mice. These results suggest that rVP1 inhibits cancer invasion/metastasis, partly if not mainly, via downregulating integrin/PI3K/Akt, ILK and IKK/NF-κB signaling to suppress expression of COX-2/PGE2 and MIG-7.

MIG-7 and phosphorylated prohibitin coordinately regulate lung cancer invasion/metastasis

Growth factors and COX-2/PGE2 enhance lung cancer invasion/metastasis via PI3K/Akt and RAS/Raf. Here, we explored their mechanism of action further. We found first that higher levels of migration inducting gene-7 protein (MIG-7) and PHB phosphorylated at threonine 258 (phospho-PHBT258) are positively correlated with advanced stages of human lung cancer in tissue microarray. PGE2 or growth factors such as EGF, HGF and IGF-1 increased complex formation of phospho-PHBT258 with Ras, phospho-AktS473, phospho-Raf-1S338, MEKK1 and IKKα/βS176/180 in the raft domain transiently within 1 hour and MIG-7 in the cytosol 12-24 hours later. Association of phospho-PHBT258 with MEKK1 but not MEKK3 activates IKK/IκB/NF-κB and MEK/ERK to increase cellular COX-2/PGE2 and an E-cadherin suppressor Snail leading to enhancement of epithelial-mesenchymal transition (EMT) and lung cancer migration/invasion. MIG-7, on the other hand, was induced by growth factors and PGE2 via Akt/GSK-3β in a phospho-PHBT258 independent manner. MIG-7 increased two E-cadherin suppressors ZEB-1 and Twist to enhance EMT and cancer migration/invasion. Downregulating phospho-PHBT258 and MIG-7 had an additive effect on attenuating lung cancer invasion/metastasis and prolonging the survival of xenograft mice. Phospho-PHBT258 and MIG-7 may thus play complementary roles in the initiation and sustainment of the effects of growth factors and COX-2/PGE2 on cancer invasion/metastasis.

MIG-7 controls COX-2/PGE2-mediated lung cancer metastasis

More effective treatments for metastatic lung cancer remain a pressing clinical need. In this study, we identified migration inducting gene-7 (MIG-7) protein as critical for COX-2/prostaglandin E2 (PGE2)- and Akt/GSK-3β-dependent tumor invasion/metastasis. COX-2/PGE2 activated EP4 to enhance Akt and GSK-3β phosphorylation and β-catenin/T-cell factor/lymphoid enhancer factor signaling leading to MIG-7 upregulation. RNAi-mediated attenuation of MIG-7 blocked COX-2/PGE2- and Akt/GSK-3β-mediated migration/invasion effects. Furthermore, MIG-7 protein inhibited protein phosphatase 2A to sustain Akt/GSK-3β phosphorylation and cancer-cell migration/invasion. Cancer cells overexpressing MIG-7 exhibited increased expression of ZEB-1 and Twist in parallel with epithelial-mesenchymal transition, metastasis and cancer lethality. MIG-7 protein level positively correlated with advanced stages of human lung cancers. MIG-7 thus offers a theranostic target for cancer metastases arising from aberrant activation of the cellular COX-2/PGE2 and Akt/GSK-3β signaling pathways.

Loss of function of e-cadherin in embryonic stem cells and the relevance to models of tumorigenesis

E-cadherin is the primary cell adhesion molecule within the epithelium, and loss of this protein is associated with a more aggressive tumour phenotype and poorer patient prognosis in many cancers. Loss of E-cadherin is a defining characteristic of epithelial-mesenchymal transition (EMT), a process associated with tumour cell metastasis. We have previously demonstrated an EMT event during embryonic stem (ES) cell differentiation, and that loss of E-cadherin in these cells results in altered growth factor response and changes in cell surface localisation of promigratory molecules. We discuss the implication of loss of E-cadherin in ES cells within the context of cancer stem cells and current models of tumorigenesis. We propose that aberrant E-cadherin expression is a critical contributing factor to neoplasia and the early stages of tumorigenesis in the absence of EMT by altering growth factor response of the cells, resulting in increased proliferation, decreased apoptosis, and acquisition of a stem cell-like phenotype.

Molecular regulation of vasculogenic mimicry in tumors and potential tumor-target therapy

“Vasculogenic mimicry (VM)”, is a term that describes the unique ability of highly aggressive tumor cells to express a multipotent, stem cell-like phenotype, and form a pattern of vasculogenic-like networks in three-dimensional culture. As an angiogenesis-independent pathway, VM and/or periodic acid-schiff-positive patterns are associated with poor prognosis in tumor patients. Moreover, VM is resistant to angiogenesis inhibitors. Here, we will review the advances in research on biochemical and molecular signaling pathways of VM in tumors and on potential anti-VM therapy strategy.

Integrins in cancer: biological implications and therapeutic opportunities

The integrin family of cell adhesion receptors regulates a diverse array of cellular functions crucial to the initiation, progression and metastasis of solid tumours. The importance of integrins in several cell types that affect tumour progression has made them an appealing target for cancer therapy. Integrin antagonists, including the alphavbeta3 and alphavbeta5 inhibitor cilengitide, have shown encouraging activity in Phase II clinical trials and cilengitide is currently being tested in a Phase III trial in patients with glioblastoma. These exciting clinical developments emphasize the need to identify how integrin antagonists influence the tumour and its microenvironment.

Targeting migration inducting gene-7 inhibits carcinoma cell invasion, early primary tumor growth, and stimulates monocyte oncolytic activity

Expression of Migration inducting gene-7 (Mig-7) is limited to tumor cells and to date not found in normal tissues. Multiple tumor microenvironment factors, such as epidermal and hepatocyte growth factors, in concert with alphavbeta5 integrin ligation, induce Mig-7 mRNA expression. Gain or loss of Mig-7 protein studies shows that Mig-7 promotes invasion of colon and endometrial carcinoma cells. These data led us to hypothesize that targeting Mig-7 through various methods could decrease invasion, enhance monocyte cell killing of tumor cells, and inhibit disease progression. To begin testing this hypothesis, an in vitro chemoinvasion assay of endometrial carcinoma cells treated with Mig-7-specific or control antibodies was used. Mig-7 antibody significantly reduced invasion by >60% compared with controls. In another approach to test this hypothesis, an in vitro analysis of peptide-stimulated human peripheral blood monocyte cells and their killing of MCF-7 breast carcinoma cells was used. Mig-7 peptide treatment increased monocyte cell tumor necrosis factor expression and killing of MCF-7 cells 30-fold over no peptide stimulation and 3-fold over MUC-1 or control peptide treatments. Furthermore, stably expressing Mig-7-specific short hairpin RNA resulted in significantly reduced Mig-7 protein levels and early primary tumor growth in a xenograft nude mouse model. Reduced phosphorylation of ERK1/2, Akt, and S6 kinase as well as decreased membrane-type 1 matrix metalloproteinase activity were mechanisms through which Mig-7 protein caused these effects. Based on these collective data, Mig-7 expression could be a potential candidate for future targeted cancer therapies.

Translation of an atypical human cDNA requires fidelity of apurine-pyrimidine repeat region and recoding

Gain or loss of Migration inducting gene-7 (Mig-7) protein expression functional studies suggest it causes aggressive tumor cell invasion and tumor cell vessel-like structure formation. In addition, Mig-7 expression is apparently carcinoma and trophoblast cell-specific. Mig-7 is an example of an atypical gene that is unique in its induction, translation and apparent carcinoma-specific expression. However, studies of this predominantly integral membrane protein are hampered because of the cloning and expression techniques required for detection of Mig-7 protein. Because the encoding region possesses stop codons, repeat sequences and secondary structure, we hypothesized that genetically engineered E. coli are required to maintain the number of purine-pyrimidine repeats and reading frame when producing expression plasmids containing the Mig-7 sequence. Cloning Mig-7 sequence using E. coli genetically engineered to lack recombination and rearrangement capabilities prevented extension of the repeat region. Because of multiple stop codons in the sequence, three different constructs starting from three different reading frame ATG sites were tested for protein production in a human carcinoma cell line. Mig-7 protein of ~23 kD is produced from Mig-7 cDNA that contains multiple stop codons downstream from the ATG in a Kozak consensus sequence. In silico analyses imply that multiple Mig-7 mRNA secondary structures may cause frameshifting, read-through, and/or recoding of the multiple stop codons. Experimental results support that one or more of these translational events take place. In this report, we detail requirements for cloning and expression of this novel, atypical, human gene. These techniques can be used to express this unique protein for further studies.

Epithelial-mesenchymal transition events during human embryonic stem cell differentiation

Epithelial-mesenchymal transition (EMT) occurs during embryonic development and may also be associated with the metastatic spread of epithelial tumors. During EMT, E-cadherin is down-regulated and this correlates with increased motility and invasion of cells. We show that differentiation of human embryonic stem (ES) cells in monolayer culture is associated with an E- to N-cadherin switch, increased vimentin expression, up-regulation of E-cadherin repressor molecules (Snail and Slug proteins), and increased gelatinase (matrix metalloproteinases; MMP-2 and MMP-9) activity and cellular motility, all characteristic EMT events. The 5T4 oncofetal antigen, previously shown to be associated with early human ES cell differentiation, is also part of this process. Abrogation of E-cadherin-mediated cell-cell contact in undifferentiated ES cells using neutralizing antibody (nAb) SHE78.7 resulted in increased cellular motility, altered actin cytoskeleton arrangement and a mesenchymal phenotype together with presentation of the 5T4 antigen at the cell surface. nAb-treated ES cells remained in an undifferentiated state, as assessed by OCT-4 protein expression, and did not express EMT-associated transcripts. Removal of nAb from ES cells resulted in the restoration of cell-cell contact, absence of cell surface 5T4, decreased mesenchymal cellular morphology and motility, and enabled the differentiation of the cells to the three germ layers upon their removal from the fibroblast feeder layer. We conclude that E-cadherin functions in human ES cells to stabilize the cortical actin cyoskeletal arrangement and this prevents cell surface localization of the 5T4 antigen. Furthermore, human ES cells represent a useful model system with which to study EMT events relevant to embryonic development and tumor cell metastasis.

Overexpression of carcinoma and embryonic cytotrophoblast cell-specific Mig-7 induces invasion and vessel-like structure formation

Molecular requirements for carcinoma cell interactions with the microenvironment are critical for disease progression but are poorly understood. Integrin alpha v beta 5, which senses the extracellular matrix, is important for carcinoma cell dissemination in vivo. alpha v beta 5 signaling induces Mig-7, a novel human gene product that is apparently carcinoma-specific. We hypothesized that Mig-7 expression facilitates tumor cell dissemination by increasing invasion and vasculogenic mimicry. Results show that embryonic cytotrophoblasts up-regulated Mig-7 expression before they acquired an invasive phenotype capable of pseudovasculogenesis. Mig-7 protein primarily co-localized with vasculogenic mimicry markers factor VIII-associated antigen, vascular endothelial-cadherin, and laminin 5 gamma 2 chain domain III fragment in lymph node metastases. Overexpression of Mig-7 increased gamma 2 chain domain III fragments known to contain epidermal growth factor (EGF)-like repeats that can activate EGF receptor. Interestingly, EGF also induced Mig-7 expression. Carcinoma cell adhesion to laminins was significantly reduced by Mig-7 expression. Remarkably, in two-dimensional and three-dimensional Matrigel cultures, Mig-7 expression caused invasion and vessel-like structures. Melanoma cells, which were previously characterized to invade aggressively and to undergo vasculogenic mimicry, expressed Mig-7. Taken together, these data suggest that Mig-7 expression allows cells to sense their environment, to invade, and to form vessel-like structures through a novel relationship with laminin 5 gamma 2 chain domain III fragments.

Hepatocyte growth factor-regulated genes in differentiated RAW 264.7 osteoclast and undifferentiated cells

Hepatocyte Growth Factor (HGF) and its protooncogene receptor c-Met regulate osteoclast function by activating pp60(c-Src) kinase and alpha(v)beta3 integrin. HGF causes transcription yet in osteoclast cells, this gene regulation is currently unknown. To begin characterization of HGF-regulated gene expression in osteoclast cells, we used a well characterized model of osteoclast cells. Using microarray, relative RT-PCR, and Western blot analyses, we have identified and confirmed differentially expressed genes in RAW 264.7 osteoclast cells in response to HGF. HGF regulation of transcription of these genes was concordant with microarray results. We report that HGF downregulates transcription factors, Distal-less 5 (Dlx-5), Distal-less 6 (Dlx-6) and Aristaless 4 (Alx-4), in RAW 264.7 osteoclast cells but has an inverse effect in undifferentiated RAW 264.7 cells.

Hepatocyte growth factor, its receptor, and their potential value in cancer therapies

Hepatocyte growth factor plays multiple roles in cancer, by acting as a motility and invasion stimulating factor, promoting metastasis and tumour growth. Furthermore, it acts as a powerful angiogenic factor. The pivotal role of this factor in cancer has indicated HGF as being a potential target in cancer therapies. The past few years have seen rapid progress in developing tools in targeting HGF, in the context of cancer therapies, including development of antagonists, small compounds, antibodies and genetic approaches. The current article discusses the potential value of HGF and its receptor as targets in cancer therapies, the current development in anti-HGF research, and the clinical value of HGF in prognosis and treatment.