The Association Between WAVE1 and -3 and the ARP2/3 Complex in PC 3 Cells

BACKGROUND

Actin polymerisation is stimulated by the actin-related protein (ARP) 2/3 complex and drives cell migration. This complex is activated by Wiskott-Aldrich syndrome protein family (WASP) verprolin homologous protein (WAVE) proteins. WAVE1 and -3 have been implicated in the aggressiveness of metastatic prostate cancer cells.

MATERIALS AND METHODS

Cell growth, motility and invasion were analyzed in WAVE1- and WAVE3-knockdown PC-3 cells along with the ARP2/3 inhibitor, CK-0944636. Confocal microscopy was adopted to examine protein co-localisation. Immunoprecipitation approaches were used to determine protein tyrosine phosphorylation.

RESULTS

Cell growth suppression was observed with WAVE3 knockdown and ARP2/3 inhibition. Reduced cell invasion effects observed with WAVE1 knockdown appeared to be rescued by ARP2/3 inhibition. WAVE1 and WAVE3 and ARP2 co-localisation was lost in PC-3 WAVE-knockdown cells, while increased ARP2 tyrosine phosphorylation was observed with WAVE3 knockdown.

CONCLUSION

These results implicate a contributory role of WAVE1 and -3 to the metastatic phenotype of PC-3 cells through their interaction with the ARP2/3 complex.

Potential roles of suppressor of cytokine signaling in wound healing

Wound healing is a dynamic process comprising three overlapping, highly orchestrated stages known as inflammation, proliferation and re-epithelialization, and tissue remodeling. This complex process is regulated by numerous cytokines, with dysregulation of cytokine-induced signaling leading to impaired wound healing. Suppressor of cytokine signaling (SOCS) proteins are a family of eight intracellular proteins which may hold the potential to maintain homeostasis during wound healing through their negative feedback inhibition of cytokine signaling. To date, the roles of SOCS proteins in inflammation, autoimmunity and cancer have been comprehensively illustrated; however, only a limited number of studies focused on their role in wound healing. This review demonstrates the possible links between SOCS proteins and wound healing, and also highlights the potential importance of this family in a variety of other aspects of regenerative medicine.

Importance of osteoprotegrin and receptor activator of nuclear factor κB in breast cancer response to hepatocyte growth factor and the bone microenvironment in vitro

Osteoprotegrin (OPG), receptor activator of nuclear factor κB (RANK) and RANK ligand (RANKL) are signal transducers which have pleiotropic actions. Each tumour necrosis factor receptor superfamily member has unique structural attributes which directly couples them to signalling pathways involved in cell proliferation, differentiation and survival. Previous studies have clinically linked OPG, RANK and RANKL to increasing tumour burden, metastatic bone involvement and estrogen status. This study aimed to establish the potential implications of targeting endogenously produced OPG and RANK in the osteotropic breast cancer cell line MDA-MB‑231 in vitro. Subsequently this study also aimed to explore the potential links between these molecules with regards to hepatocyte growth factor (HGF) signalling and extracted bone proteins (BME). OPG and RANK expression was successfully suppressed using hammerhead ribozyme technology. Subsequently effects were explored in MDA-MB‑231 cell proliferation, matrix adhesion, migration and invasion in vitro function assays. Reduced OPG expression resulted in increased breast cancer cell migration and invasion. These increases, particularly invasion, appeared to however be reduced under the influence of the exogenous stimuli (HGF and BME). In contrast, suppression of RANK in MDA-MB‑231 breast cancer cells resulted in decreased cancer cell proliferation, matrix-adhesion, motility and invasion with little cumulative effect being noted after the addition of exogenous stimuli. The complexity of the bone environment underpins the vast number of soluble factors and signalling pathways which can influence osteotropic cancer behaviour and progression. Further work into elucidating all the pathways affected could potentially lead to better identification of those patients most at risk.

Tumour endothelial marker-8 in wound healing and its impact on the proliferation and migration of keratinocytes

Chronic wound management represents a significant burden on healthcare systems and negatively impacts on the quality of patient life. New strategies to understand and identify wounds that will not heal in a normal manner are required. Tumour endothelial marker‑8 (TEM‑8) has been implicated in the wound healing and angiogenesis processes. TEM‑8 expression was examined at the transcript level in a cohort of acute (n=10) and chronic (n=14) wounds and in normal skin (n=10). Protein analysis of TEM‑8 was also undertaken for this cohort using immunohistochemistry (IHC). TEM‑8 impact on keratinocyte cell growth and migration was assessed following TEM‑8 ribozyme transgene transfection of human HaCaT keratinocytes using cell growth and electric cell‑substrate impedance sensing (ECIS)‑based assays. Expression of TEM‑8 was observed to be increased in acute wounds compared to chronic wounds and normal skin using quantitative polymerase chain reaction transcript analysis and IHC staining of wound tissues. Knockdown of TEM‑8 in HaCaT cells, using two independent ribozyme transgenes, resulted in significant decreases in cell growth as well as reductions in the rate of migration assessed using an ECIS‑based system. TEM‑8 may be differentially expressed between wound types and loss of this molecule impacts HaCaT growth and migration, potentially implicating this molecule as a factor involved in successful progression of wound healing.

Interleukin-24 (IL-24) Expression and Biological Impact on HECV Endothelial Cells

BACKGROUND

IL-24, also termed MDA-7, is a member of the IL-10 family of cytokines. IL-24 is reported to be expressed in a series of cell lines, including keratinocytes as well as breast, lung and prostate cancer cells, but was primarily found in a human melanoma cell line. IL-24 is suggested to have many biological properties displaying anti-tumour effects via induction of apoptosis, suppressing proliferation, invasion and metastasis of cancer cells. IL-24 has also been reported to inhibit the migration of cancer cells and keratinocytes, and have anti-angiogeneic properties. The biological functions of IL-24 are regulated through both autocrine and paracrine methods. However, currently there exists little knowledge regarding the effect of IL-24 on endothelial cell biology.

MATERIALS AND METHODS

The impact of rhIL-24 on human endothelial HECV cell growth, migration, trans-endothelial resistance and angiogenic potential was examined using cellular functional assays. Additionally, the relationship between IL-24 and a number of cell junction proteins were examined using immunofluorescence staining.

RESULTS

IL-24 and receptor molecules was found to be expressed in HECV endothelial cells. Treatment of this cell line with rhIL-24 was found to promote cell migration rates and suppress tubule formation.

CONCLUSION

Treatment of HECV cells with rhIL-24 can promote migration and inhibit tubule formation but does not impact cell growth or permeability at the tested concentrations. Potential links between IL-24 and AKT or PLCγ-related pathways with regard to these effects are also presented in the present study.

YangZheng XiaoJi exerts anti-tumour growth effects by antagonising the effects of HGF and its receptor, cMET, in human lung cancer cells

BACKGROUND

Hepatocyte growth factor (HGF) is a cytokine that has a profound effect on cancer cells by stimulating migration and invasion and acting as an angiogenic factor. In lung cancer, the factor also plays a pivotal role and is linked to a poor outcome in patients. In particular, HGF is known to work in combination with EGF on lung cancer cells. In the present study, we investigated the effect of a traditional Chinese medicine reported in cancer therapies, namely YangZheng XiaoJi (YZXJ) on lung cancer and on HGF mediated migration and invasion of lung cancer cells.

METHODS

Human lung cancer cells, SKMES1 and A549 were used in the study. An extract from the medicine was used. Cell migration was investigated using the EVOS and by ECIS. Cell-matrix adhesion and in vitro invasion were assessed. In vivo growth of lung cancer was tested using an in vivo xenograft tumour model and activation of the HGF receptor in lung tumours by an immunofluorescence method.

RESULTS

Both lung cancer cells increased their migration in response to HGF and responded to YZXJ by reducing their speed of migration. YZXJ markedly reduced the migration and in vitro invasiveness induced by HGF. It worked synergistically with PHA665752 and SU11274, HGF receptor inhibitors on the lung cancer cells both on HGF receptor activation and on cell functions. A combination of HGF and EGF resulted in a greater increase in cell migration, which was similarly inhibited by YZXJ, and in combination with the HGF receptor and EGF receptor inhibitors. In vivo, YZXJ reduced the rate of tumour growth and potentiated the effects of PHA665752 on tumour growth. It was further revealed that YZXJ significantly reduced the degree of phosphorylation of the HGF receptor in lung tumours.

CONCLUSION

YZXJ has a significant role in reducing the migration, invasion and in vivo tumour growth of lung cancer and acts to inhibit the migratory and invasive effects induced by HGF and indeed by HGF/EGF. This effect is likely attributed to the inhibition of the HGF receptor activation. These results indicate that YZXJ has a therapeutic role in lung cancer and that combined strategy with methods to block HGF and EGF should be considered.

Traditional Chinese medicine in the prevention and treatment of cancer and cancer metastasis

Traditional Chinese medicine (TCM) has been a major part of healthcare in China, and has extensively affected medicine and healthcare in surrounding countries over a long period of time. In the fight against cancer, certain anticancer remedies using herbs or herbal formulas derived from TCM have been developed for the management of malignancies. Furthermore, there are clinical trials registered for the use of herbal remedies in cancer management. Herbal medicine has been used as part of combined therapies to reduce the side-effects of chemotherapy, including bone marrow suppression, nausea and vomiting. Herbal remedies have also been used as chemopreventive therapies to treat precancerous conditions in order to reduce the incidence of cancer in high-risk populations. Emerging evidence has revealed that herbal remedies can regulate the proliferation, apoptosis, adhesion and migration of cancer cells. In addition to this direct effect upon cancer cells, a number of herbal remedies have been identified to suppress angiogenesis and therefore reduce tumour growth. The inhibition of tumour growth may also be due to modifications of the host immune system by the herbal treatment. However, the precise mechanisms underlying the therapeutic effects of herbal remedies remain poorly understood and are yet to be fully elucidated. The present study aims to summarize the current literature and clinical trial results of herbal remedies for cancer treatment, with a particular focus on the recent findings and development of the Yangzheng Xiaoji capsule.

Epithelial-mesenchymal Transition (EMT) Markers in Human Pituitary Adenomas Indicate a Clinical Course

BACKGROUND/AIM

Pituitary adenomas are brain tumors with invasive properties. Epithelial-mesenchymal-transition (EMT) is a cellular process linked to the transformation to an aggressive cancer phenotype. In the present study, we investigated the expression of a panel of EMT markers, namely E-cadherin, N-cadherin, SLUG, SNA1 and TWIST in a cohort of human pituitary adenomas.

MATERIALS AND METHODS

Fresh-frozen human pituitary tumors (n=95) were collected immediately after surgery for histology. Gene transcripts of the EMT markers were quantified using quantitative-polymerase chain reaction (PCR) analysis. Levels of expression were analyzed against clinical, pathological, invasion and endocrine functions.

RESULTS

Levels of E-cadherin and N-cadherin had a negative and positive correlation with the appearance of intratumoral cystic lesions of pituitary tumors. E-cadherin and TWIST were associated with tumor size and staging. There was a significant link between SLUG/TWIST and the destruction of the sella fosa bones (p<0.030). EMT markers also showed links with the endocrine functions of pituitary tumors. In pituitary tumors, SLUG and SNA1 had significant correlation with N-cadherin.

CONCLUSION

EMT markers are significant indicators of the appearance of cystic lesions, tumor progression, bone destruction and endocrine functions. These markers are valuable biomarkers in assessing the clinical course of pituitary adenomas.

Expression of metastasis-associated gene-1 is associated with bone invasion and tumor stage in human pituitary adenomas

BACKGROUND

Metastasis associated gene-1 (MTA1), was initially discovered in aggressive human cancer cell lines and has been subsequently associated with the invasiveness and metastatic potential of cancer cells.

MATERIALS AND METHODS

In the present study, we evaluated the expression levels of MTA1 in a cohort of human pituitary tumors (n=95) and examined the relationship between MTA1 expression and the pathological, clinical and aggressiveness of these tumors.

RESULTS

MTA1 was expressed at significantly higher levels in large tumors and in those with higher tumor grade. It was also observed that tumors that had invaded the suprasellar bones and tumors that destructed the sella had significantly higher levels than those without bone involvement (p<005). Although there did not appear to exist any relationship between MTA1 and cystic lesions in the tumors, endocrine-active tumors, namely those secreting prolactin, growth hormone, Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) had significantly lower MTA1 transcript levels than inactive tumors.

CONCLUSION

MTA1 is associated with the aggressive nature of pituitary tumors and may be a potential therapeutic target in this tumor type.

Effects of the knockdown of death-associated protein 3 expression on cell adhesion, growth and migration in breast cancer cells

The death-associated protein 3 (DAP3) is a highly conserved phosphoprotein involved in the regulation of autophagy. A previous clinical study by our group suggested an association between low DAP3 expression and clinicopathological parameters of human breast cancer. In the present study, we intended to determine the role of DAP3 in cancer cell behaviour in the context of human breast cancer. We developed knockdown sub-lines of MCF7 and MDA-MB-231, and performed growth, adhesion, invasion assays and electric cell-substrate impedance sensing (ECIS) studies of post-wound migration of the cells. In addition, we studied the mRNA expression of caspase 8 and 9, death ligand signal enhancer (DELE), IFN-β promoter stimulator 1 (IPS1), cyclin D1 and p21 in the control and knockdown sub-lines. The knockdown sub-lines of MCF7 and MDA-MB-231 had significantly increased adhesion and decreased growth when compared to the controls. Furthermore, invasion and migration were significantly increased in the MDA-MB-231DAP3kd cells vs. the controls. The expression of caspase 9 and IPS1, known components of the apoptosis pathway, were significantly reduced in the MCF7DAP3kd cells (p=0.05 and p=0.003, respectively). We conclude that DAP3 silencing contributes to breast carcinogenesis by increasing cell adhesion, migration and invasion. It is possible that this may be due to the activity of focal adhesion kinase further downstream of the anoikis pathway. Further research in this direction would be beneficial in increasing our understanding of the mechanisms underlying human breast cancer.

Expression of Sonic Hedgehog (SHH) in human lung cancer and the impact of YangZheng XiaoJi on SHH-mediated biological function of lung cancer cells and tumor growth

Sonic Hedgehog (SHH) is a protein that is aberrantly expressed in various human tumors. SHH and its signaling molecules have been indicated as potential therapeutic targets. In the present study, we evaluated the expression of SHH transcript in human non-small cell lung cancer (NSCLC) tissues and investigated the impact of inhibiting SHH together with a traditional Chinese medicine formula, YangZheng XiaoJi (YZXJ), on the function and growth of lung cancer cells. Human NSCLC tissues had significantly higher levels of the SHH transcript compared matched normal lung tissues (n=83). TNM2 tumors and tumors with pleural invasion had higher levels than TNM1 and non-invasive tumors. High SHH levels were associated with a shorter overall survival (OS) of the patients. A SHH inhibitor, cyclopamine, and YZXJ alone or in combination had a marked inhibitory effect on cellular invasion and cellular migration of human lung cancer cells, A549 and SKMES1. YangZheng XiaoJi and its combination with cyclopamine also significantly reduced the growth of lung tumors in vivo together with a reduction of SHH and smoothened (Smo) proteins in the lung tumors. The present study provides evidence that blocking SHH by way of small inhibitor and by YangZheng XiaoJi has a profound influence on lung cancer cells as seen by in vitro invasion and cell migration and in vivo tumor growth. Together with the aberrant expression of SHH in NSCLC tumors in the patients, it is suggested that SHH is a potential target for therapies for NSCLC.

Expression of Hepatocyte Growth Factor-Like Protein in Human Wound Tissue and Its Biological Functionality in Human Keratinocytes

human keratinocyte model, may indicate a role for HGFl in active wound healing.

Therapeutic potential of capillary morphogenesis gene 2 extracellular vWA domain in tumour‑related angiogenesis

Capillary morphogenesis gene 2 (CMG2) is a receptor of anthrax toxin and plays an important role in angiogenesis. It has been shown to be involved in the cell adhesion and motility of various cell types, including epithelia and endothelia. The present study aimed to examine the therapeutic potential of targeting CMG2 to prevent tumour‑related new vasculature. The full-length coding sequence of the human CMG2 gene and different fragments of the CMG2 vWA domain were amplified and constructed into a mammalian expression plasmid vector. The effect of CMG2 and its vWA domain on endothelial cells and angiogenesis was assessed using relevant in vitro, ex vivo and in vivo models. The overexpression of CMG2 enhanced the adhesion of endothelial cells to extracellular matrix, but was negatively associated with cell migration. Overexpression of CMG2 and the vWA domain fragments inhibited the tubule formation and migration of endothelial cells. Small peptides based on the amino acid sequence of the CMG2 vWA domain fragments potently inhibited in vitro tubule formation and ex vivo angiogenesis. One of the polypeptides, LG20, showed an inhibitory effect on in vivo tumour growth of cancer cells which were co-inoculated with the vascular endothelial cells. CMG2 is a potential target for treating tumour‑related angiogenesis. The polypeptides based on the CMG2 vWA domain can potently inhibit in vitro and ex vivo angiogenesis, which may contribute to the inhibitory effect on in vivo tumour growth. Further investigations are required to shed light on the machinery and may provide a novel therapeutic approach for inhibition of angiogenesis in cancer management.

Tumour angiogenesis and repulsive guidance molecule b: a role in HGF- and BMP-7-mediated angiogenesis

Hepatocyte growth factor (HGF) is a key growth factor linked to promoting cancer progression and angiogenesis. The present study identifies repulsive guidance molecule b (RGMb), a bone morphogenetic protein (BMP) co-receptor, as a gene whose expression is regulated by HGF and explores the potential of RGMb to contribute to the process of angiogenesis. Microarray analysis was used to identify HGF responsive genes in HECV endothelial cells, identifying RGMb. RGMb was subsequently targeted using a ribozyme transgene system and its role in angiogenesis assessed using in vitro and in vivo assays. The importance of RGMb in pro-angiogenic responses to HGF and BMP-7 was also assessed. Microarray analysis identified RGMb as a gene upregulated as a result of HGF treatment. Knockdown of RGMb, in HECV cells, had minimal effects on tubule formation, brought about a general, although non-significant increase in cell growth and enhanced cell migration. Similarly, no significant effect of RGMb knockdown was found in vivo using a co-inoculation angiogenesis model. Knockdown of RGMb was, however, found to reduce the responsiveness of HECV cells to HGF treatment and particularly to BMP-7 treatment in regard to the enhanced migratory and tubule formation brought about by these treatments in vitro. Our results indicate that RGMb expression can be influenced by HGF treatment. Whilst this molecule appears to have minimal impact on angiogenic traits individually, it demonstrates an involvement in propagating pro-angiogenic effects of HGF and particularly BMP-7 and thus, may play a role in regulating angiogenic responses to HGF and BMP-7.

Electrophysiological evidence of heterogeneity in visual statistical learning in young children with ASD

Statistical learning is characterized by detection of regularities in one's environment without an awareness or intention to learn, and it may play a critical role in language and social behavior. Accordingly, in this study we investigated the electrophysiological correlates of visual statistical learning in young children with autism spectrum disorder (ASD) using an event-related potential shape learning paradigm, and we examined the relation between visual statistical learning and cognitive function. Compared to typically developing (TD) controls, the ASD group as a whole showed reduced evidence of learning as defined by N1 (early visual discrimination) and P300 (attention to novelty) components. Upon further analysis, in the ASD group there was a positive correlation between N1 amplitude difference and non-verbal IQ, and a positive correlation between P300 amplitude difference and adaptive social function. Children with ASD and a high non-verbal IQ and high adaptive social function demonstrated a distinctive pattern of learning. This is the first study to identify electrophysiological markers of visual statistical learning in children with ASD. Through this work we have demonstrated heterogeneity in statistical learning in ASD that maps onto non-verbal cognition and adaptive social function.

Capillary morphogenesis gene 2 regulates adhesion and invasiveness of prostate cancer cells

Capillary morphogenesis gene 2 (CMG2), also known as anthrax toxin receptor 2, has been indicated in the formation of new vasculature and in the internalisation of the anthrax toxin. Anti-angiogenesis therapy that targets this molecule has been investigated. However, our recent studies of this molecule have indicated that this gene may also play certain roles in cancer cells. The present study aimed to examine the expression of CMG2 in prostate cancer tissues and cell lines, and also its impact on cellular functions. The expression of CMG2 was detectable in normal and prostate cancer tissues. The prostate cancer cell lines appeared to have relatively high expression compared with the prostatic epithelial cells. Knockdown of CMG2 impaired the adherence of the prostate cancer cells. CMG2 overexpression resulted in decreasing invasiveness, while the knockdown of CMG2 contrastingly enhanced this ability. The altered expression of CMG2 in the prostate cancer cells did not affect the in vitro or in vivo growth of the cells. Taken together, these results show that CMG2 is expressed in prostatic epithelia and cancer cells. In addition to its role in the angiogenesis and the internalisation of anthrax toxin, CMG2 also plays an important role in regulating the adhesion and invasion of prostate cancer cells.

Abstract P6-02-02: mRNA expression of death associated protein 3 (DAP3) and human breast cancer: Clinical correlations and in vitro evidence

BACKGROUND: To our knowledge, this study is the first to focus on the potential role for death-associated protein 3 (DAP3) in human breast cancer.

MATERIAL AND METHODS: mRNA expression of DAP3 in breast cancer tissues (n = 127) and normal background tissues (n = 33) were determined using quantitative polymerase chain reaction (qPCR) and were correlated with clinico-pathological data accumulated over a 10-year follow-up period.

Furthermore the effects of DAP3 knock down in breast cancer cell lines (MCF-7 and MDA-MB-231) were investigated. The cells were subjected to conventional growth, adhesion and invasion assays.

In addition to the above, electric cell-substrate impedance sensing (ECIS) assay and annexin V/propidium iodide binding apoptosis assay were performed. For the apoptosis assay, the cells were subjected to 48 to 72 hours of serum hunger (depending on cell line) before being analyzed using a flow cytometer.

RESULTS: The expression of DAP3 mRNA was demonstrated to decrease with increasing Nottingham Prognostic Index (NPI2 vs. NPI3, p = 0.036), TNM stage (TNM1 vs. 3, p = 0.07), and tumour grade (grade 1 vs. 3, p = 0.08). Lower DAP3 expression levels were significantly associated with local recurrence (p = 0.013), distant metastasis (p = 0.0057) and mortality (p = 0.019).

Kaplan-Meier plot analysis suggests that patient with higher levels of DAP3 expression had better overall survival compared to patients with lower levels of DAP3 expression (p = 0.075).

DAP3 knock down strains in both cell lines demonstrated increased growth and migration compared to controls during ECIS.

In addition, DAP3 knock down strains of MCF-7 appeared more resistant to serum hunger when compared to controls during the apoptosis assay.

CONCLUSIONS: This study demonstrates an inverse association between DAP3 mRNA levels and tumour stage and clinical stage in breast cancer. This is in keeping with the role of DAP3 as a pro-apoptotic protein. The in vitro evidence lends further credence to this hypothesis. The role of DAP3 may require further investigation to better understand the role of apoptosis in breast carcinogenesis, and may potentially serve as a prognostic marker for human breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-02-02.

Prostate transglutaminase (TGase-4, TGaseP) enhances the adhesion of prostate cancer cells to extracellular matrix, the potential role of TGase-core domain

Background

Transglutaminase-4 (TGase-4), also known as the Prostate Transglutaminase, is an enzyme found to be expressed predominately in the prostate gland. The protein has been recently reported to influence the migration and invasiveness of prostate cancer cells. The present study aimed to investigate the influence of TGase-4 on cell-matrix adhesion and search for the candidate active domain[s] within the protein.

Methods

Human prostate cancer cell lines and prostate tissues were used. Plasmids that encoded different domains and full length of TGase-4 were constructed and used to generate sublines that expressed different domains. The impact of TGase-4 on in vitro cell-matrix adhesion, cell migration, growth and in vivo growth were investigated. Interactions between TGase-4 and focal adhesion complex proteins were investigated using immunoprecipitation, immunofluorescence and phosphospecific antibodies.

Results

TGase-4 markedly increased cell-matrix adhesion and cellular migration, and resulted in a rapid growth of prostate tumours in vivo. This effect resided in the Core-domain of the TGase-4 protein. TGase-4 was found to co-precipitate and co-localise with focal adhesion kinase (FAK) and paxillin, in cells, human prostate tissues and tumour xenografts. FAK small inhibitor was able to block the action mediated by TGase-4 and TGase-4 core domain.

Conclusion

TGase-4 is an important regulator of cell-matrix adhesion of prostate cancer cells. This effect is predominately mediated by its core domain and requires the participation of focal adhesion complex proteins.

Expression of the mTOR pathway regulators in human pituitary adenomas indicates the clinical course

Pituitary ademonas are benign tumours with different biological behaviour, especially with regard to tumour size, invasion, endocrine function, intratumour cystic lesion and apoplexy. There is little understanding of the growth and the control of progression of pituitary tumours. In the present study, we investigated the expression of mammalian target of rapamycin (mTOR) pathway regulators, in clinical pituitary adenomas. Pituitary adenomas from 95 patients were included in the study. Fresh pituitary tumours were obtained immediately after surgery and processed for histological, immunohistological and molecular based analyses. Histolopathological and clinical information including tumour stage, invasion characteristic and endocrine status were analysed against the gene transcript expression of mTOR, RAPTOR and RICTOR. There was a stepwise and significantly increased relation-ship between RICTOR expression and tumour size, namely p=0.0012 and p=0.0055 for tumours 1-2 cm and tumours >3 cm compared with tumours <1 cm respectively. Significantly higher levels of mTOR were seen in tumours with cystic lesions (p=0.044). There was no significant correlation between mTOR, RAPTOR and RICTOR and tumour apoplexy, nor a correlation between mTOR, RAPTOR and RICTOR with suprasephanous spread and sella floor destruction. However, pituitary tumours with cavernous sinus invasion, namely Knosp stage 3-4 had significantly lower levels of RAPTOR than those of Knosp stage 1-2 (p=0.01). A similar but statistically insignificant trend was seen with RICTOR. Using modified Hardy's staging, it was found that there was a significant correlation between tumour stage and RAPTOR and RICTOR expression. mTOR and RAPTOR levels differed in tumours with different endocrine functions, although no statistical difference was observed. However, Growth Hormone (GH) -, Follicle-Stimulating Hormone (FSH)-, Thyroid Stimulating Hormone (TSH)-secreting tumours had significantly lower levels of RICTOR compared with nonfunctional tumours. Finally, levels of mTOR were found to be significantly correlated with levels of both RAPTOR and RICTOR. It is noteworthy that RAPTOR and RICTOR levels were also significantly correlated. In conclusion, mTOR pathway regulators, mTOR, RAPTOR and RICTOR are significantly correlated with the invasion, staging, and tumour growth of pituitary adenomas and thus have an important predictive and prognostic value in patients with pituitary adenoma.

A role for WISP2 in colorectal cancer cell invasion and motility

BACKGROUND

WNT inducible secreted protein 2 (WISP2) has been linked with a variety of human cancer types and may contribute to cancer metastasis. The current study investigated the importance of WISP2 in colorectal cancer cells, examining the impact of targeting WISP2 on Caco-2 cell invasion and motility together with potential mechanisms of action.

MATERIALS AND METHODS

WISP2 expression was targeted in Caco-2 cells using a ribozyme transgene system and successful knockdown was verified using reverse transcription-polymerase chain reaction (RT-PCR). The impact of WISP2 knockout (Caco-2(WISP2 KO)) on cell growth, adhesion, motility and invasion was examined using a number of in vitro functional assays. In vitro invasion assays were repeated in the presence of wingless-type MMTV integration site family (WNT) inhibitors (FH535 and IWP-2) to investigate the role of the WNT-signalling pathway in the regulation of cell invasion by WISP2. Quantitative-PCR was conducted to measure matrix metalloproteinase (MMP) expression in control [wild-type (Caco-2(WT)) and cells containing the empty pEF6 plasmid (Caco-2(pEF6))] and Caco-2(WISP2 KO) cells.

RESULTS

WISP2 knockout resulted in a significant increase in Caco-2 cell invasion and motility (p<0.05 in comparison to wild-type and plasmid control Caco-2 cells). WISP2 knockout had no significant effect on Caco-2 cell growth rate in 3- and 5-day incubation and no significant impact on Caco-2 cell-matrix adhesion rates (p>0.05). Expression analysis of a number of MMPs indicated an insignificant up-regulation of MMP2, MMP9 (p>0.05) but significant up-regulation of MMP7 (p=0.025) in Caco-2(WISP2 KO) cells compared to controls. Inhibition of WNT signalling using FH535 and IWP-2 brought about a significant or borderline significant decrease in Caco-2(WISP2 KO) cell invasion (FH535 p=0.065) and (IWP-2 p=0.002) and negated the pro-invasive effect of targeting WISP2 in Caco-2 cells.

CONCLUSION

WISP2 knockout significantly increased Caco-2 cell invasion and motility. Up-regulation of MMP2, -7 and -9 may indicate that WISP2 regulates invasion and motility through MMPs. Regulation of invasion by WISP2 may involve the WNT signalling pathway.

The impact of angio-associated migratory cell protein (AAMP) on breast cancer cells in vitro and its clinical significance

BACKGROUND/AIM

Angio-associated migratory cell protein (AAMP), which belongs to the immunoglobulin superfamily, was found to be expressed in different human cell lines and exhibited a predominant cytosolic localization in epithelial cells. Previous studies show that the specific gene product is functional in cell migration and angiogenesis and can also be used as a marker of poor prognosis in invasive gastrointestinal stromal tumours and ductal carcinoma in situ (DCIS) of the breast. However, the cellular role of AAMP in breast cancer is still unclear. The aim of the current study was to provide new insights into the implication of AAMP in breast cancer.

MATERIALS AND METHODS

We knocked-down the expression of AAMP through transfection of MCF-7 and MDA-MB-231 breast cancer cells with a hammerhead ribozyme transgene (MCF-7(AAMPrib) and MDA-MB-231(AAMPrib)) and examined the impact on cell function using in vitro assays. Additionally, AAMP expression was examined in a cohort of breast specimens (normal, n=28; cancer, n=102) using quantitative-real-time polymerase chain reaction (Q-PCR) and immunohistochemical methods.

RESULTS

AAMP knock-down dramatically reduced cell adhesion and cell growth of MCF-7 cells (p<0.05), and suppressed cell invasion of MDA-MB-231 cells (p<0.05). Increased expression of AAMP in breast cancer was observed compared with that in normal tissues (p<0.05). High levels of AAMP transcripts were associated with disease progression, metastasis, and poor prognosis of the patients. Disease-free and overall survival time of patients with lower levels of AAMP were significantly longer compared to those of patients with high levels (p<0.05).

CONCLUSION

AAMP has a significant influence on the biological functions of breast cancer cells and its high expression correlates with poor prognosis and metastasis.

Expression of death receptor-3 in human breast cancer and its functional effects on breast cancer cells in vitro

Death receptor-3 (DR3) plays controversial roles in cancer. Currently, DR3 is known to be a functional receptor of vascular endothelial growth inhibitor (VEGI). The role of DR3 in breast cancer remains unclear. The present study investigated DR3 expression in a clinical cohort of breast cancer patients and its role in breast cancer cells in vitro. The expression of DR3 was examined in a breast cancer cohort using quantitative PCR (Q-PCR) and immunohistochemistry (IHC) in comparison to the patients' data. In vitro function of DR3 was examined through the targeting of this molecule in MCF7 and MDA-MB-231 breast cancer cells using ribozyme transgene technology. Decreased DR3 expression was noted in breast cancer tissues compared to normal tissues and decreased expression of DR3 was generally associated with a poorer prognosis as well as a significantly shorter long-term survival (p=0.038). Targeting of DR3 in vitro in breast cancer cell lines resulted in impaired migratory rates compared to respective control cells. Collectively, these data suggest a complex role for DR3 in breast cancer development and progression.

Expression profile of receptor activator of nuclear-κB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) in breast cancer

BACKGROUND

Breast cancer, the most common cancer affecting women in the USA and UK, is known to have a high frequency of osteolytic bone metastasis. Receptor activator of nuclear-κB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) are a group of important regulators for osteoclast differentiation and activation. These molecules have been implicated in bone metastasis. Since the discovery of the triad of RANK, RANKL and OPG in healthy bone turnover, a better understanding of these factors in bone metastasis has been sought.

MATERIALS AND METHODS

Using our clinical breast cancer cohort, the transcript levels of RANK, RANKL and OPG were examined using real-time quantitative-polymerase chain reaction (qPCR). Expression of these molecules in the immortalised breast cancer cell lines MCF-7 and MDA-MB-231 was also analyzed using qPCR following treatment with β-oestradiol in a concentration-dependent manner.

RESULTS

RANK, RANKL and OPG were all shown to be expressed in the breast cancer cell lines examined. Transcript levels were shown to be reduced in tumour samples when compared with normal tissue. Reduced RANK expression was associated with a worse clinical outcome and levels were significantly reduced in patients with general metastasis, bone metastasis and those who had died of the disease. Patients with reduced RANKL expression were more likely to develop local recurrence, bone metastasis or die from the disease. Using Kaplan-Meier survival analysis, lower expression levels of OPG were found to be associated with significantly better overall patient survival in our cohort.

CONCLUSION

The corresponding prognostic and therapeutic potential is yet to be further investigated. Our data suggest that RANK, RANKL and OPG may potentially be used as novel prognostic markers for bone metastasis and provide new therapeutic targets in the treatment of breast cancer.

Matriptase-2 inhibits HECV motility and tubule formation in vitro and tumour angiogenesis in vivo

The type II transmembrane serine proteases (TTSP) are cell surface proteolytic enzymes that mediate a diverse range of cellular functions, including tumour invasion and metastasis. Matriptase-2 is a member of the TTSP family and has been shown to have a key role in cancer progression. The role of matriptase-2 in angiogenesis and angiogenesis-related cancer progression is currently poorly understood. This study aims to elucidate the role of matriptase-2 in tumour angiogenesis. Matriptase-2 was over-expressed in human vascular endothelial cells, HECV, using a mammalian expression plasmid. The altered cells were used in a number of in vitro and in vivo assays designed to investigate the involvement of matriptase-2 in angiogenesis. Over-expression had no significant effect on the growth and adhesion of HECV cells. However, there was a significant reduction in the motility of the cells and their ability to form tubules in an artificial basement membrane (p < 0.01 for both). HECV(mat2 exp) cells inoculated into CD-1 athymic mice along with either PC-3 prostate cancer cells or MDA-MB-231 breast cancer cells showed a dramatic decrease in tumour development and growth in the prostate tumours (p < 0.01) and a lesser, non-significant, decrease in the breast tumours (p = 0.08). Over-expression of matriptase-2 also decreased urokinase type plasminogen activator total protein levels in HECV and prostate cells. The study concludes that matriptase-2 has the ability to suppress the angiogenic nature of HECV cells in vitro and in vivo. It also suggests that matriptase-2 could have a potential role in prostate and breast tumour suppression through its anti-angiogenic properties.

Expression of IL-24 and IL-24 receptors in human wound tissues and the biological implications of IL-24 on keratinocytes

Interleukin (IL)-24, also known as melanoma differentiation-associated gene-7, is a cytokine initially identified from cancerous cells and expressed in a range of cell types. It is a regulator of cell differentiation, growth, and apoptosis, and a promising anticancer agent. IL-24 acts via its heterodimic receptors: the IL-20R1 and IL-20R2 complex and the IL-22R1 and IL-20R2 complex. There is limited information on the effect of IL-24 in wound healing. Human acute and chronic wound tissues were used to analyze the transcript levels and histological staining of IL-24 and the IL-24 receptors. The biological response of human keratinocytes to recombinant human IL-24 was evaluated using electric cell-substrate impedance sensing-based methods in conjunction with inhibitors to candidate signaling pathways. IL-24 significantly slowed the migration of keratinocytes (p = 0.01), with only a marginal effect on cellular adhesion. The inhibitory effect of IL-24 on migration was completed reversed following addition of an AKT inhibitor (p = 0.004) but not an SMAD3 pathway inhibitor. Human chronic wound tissues showed raised levels of both IL-24 (p = 0.003) and its receptor (p = 0.0305) compared with acute wound tissues. We conclude that IL-24 appears to promote wound chronicity via its inhibitory effect on the migratory behavior of human keratinocytes, mediated through an AKT-dependent pathway.

Repulsive guidance molecule B (RGMB) plays negative roles in breast cancer by coordinating BMP signaling

Repulsive guidance molecules (RGMs) coordinate axon formation and iron homestasis. These molecules are also known as co-receptors of bone morphogenetic proteins (BMPs). However, the role played by RGMs in breast cancer remains unclear. The present study investigated the impact of RGMB on functions of breast cancer cells and corresponding mechanisms. RGMB was knocked down in breast cancer cells by way of an anti-RGMB ribozyme transgene. Knockdown of RGMB resulted in enhanced capacities of proliferation, adhesion, and migration in breast cancer cells. Further investigations demonstrated RGMB knockdown resulted in a reduced expression and activity of Caspase-3, accompanied with better survival in RGMB knockdown cells under serum starvation, which might be induced by its repression on MAPK JNK pathway. Up-regulations of Snai1, Twist, FAK, and Paxillin via enhanced Smad dependent sigaling led to increased capacities of adhesion and migration. Our current data firstly revealed that RGMB may act as a negative regulator in breast cancer through BMP signaling.

CFTR suppresses tumor progression through miR-193b targeting urokinase plasminogen activator (uPA) in prostate cancer

Cystic fibrosis (CF) transmembrane conductance regulator (CFTR) is expressed in the epithelial cells of a wide range of organs/tissues from which most cancers are derived. Although accumulating reports have indicated the association of cancer incidence with genetic variations in CFTR gene, the exact role of CFTR in cancer development and the possible underlying mechanism have not been elucidated. Here, we report that CFTR expression is significantly decreased in both prostate cancer cell lines and human prostate cancer tissue samples. Overexpression of CFTR in prostate cancer cell lines suppresses tumor progression (cell growth, adhesion and migration), whereas knockdown of CFTR leads to enhanced malignancies both in vitro and in vivo. In addition, we demonstrate that CFTR knockdown-enhanced cell proliferation, cell invasion and migration are significantly reversed by antibodies against either urokinase plasminogen activator (uPA) or uPA receptor (uPAR), which are known to be involved in various malignant traits of cancer development. More interestingly, overexpression of CFTR suppresses uPA by upregulating the recently described tumor suppressor microRNA-193b (miR-193b), and overexpression of pre-miR-193b significantly reverses CFTR knockdown-enhanced malignant phenotype and abrogates elevated uPA activity in prostate cancer cell line. Finally, we show that CFTR gene transfer results in significant tumor repression in prostate cancer xenografts in vivo. Taken together, the present study has demonstrated a previously undefined tumor-suppressing role of CFTR and its involvement in regulation of miR-193b in prostate cancer development.

Psoriasin (S100A7) is a positive regulator of survival and invasion of prostate cancer cells

OBJECTIVES

Psoriasin, also known as S100A7 and first identified as a protein highly expressed in psoriatic lesions, is a calcium binding protein that has been indicated in various malignancies. The current study aimed to examine the implication of psoriasin in prostate cancer (CaP), particularly its impact on functions of CaP cells.

MATERIALS AND METHODS

Expression of psoriasin was examined in a variety of prostatic cell lines and human CaP tissues using reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. Knockdown and overexpression of psoriasin in CaP cells was performed using specifically constructed plasmids, which either had an anti-psoriasin ribozyme transgene or the full-length human S100A7 coding sequence. The effects of manipulating psoriasin expression on cellular functions of CaP cells were assessed using in vitro assays.

RESULTS

Psoriasin was expressed in prostate epithelia and cancer cells. Elevated expression of psoriasin was evident in CaP from its IHC staining in CaP frozen specimens. Psoriasin promoted cell survival under serum starvation. Its expression was inversely correlated with cell-matrix adhesion. Psoriasin increased invasiveness of PC-3 cells via a regulation of matrix metalproteinases (MMPs).

CONCLUSIONS

Aberrant expression of psoriasin is implicated in CaP. Its expression in CaP cells is associated with cell survival, adhesion, and in vitro invasion, which is via the regulation of MMPs.

EPLIN-α expression in human oesophageal cancer and its impact on cellular aggressiveness and clinical outcome

BACKGROUND

Epithelial protein lost in neoplasm-α (EPLIN-α) is a cytoskeletal protein whose expression is often lost or is aberrant in cancerous cells and tissues and whose loss is believed to be involved in aggressive phenotype. Our current study examined this molecule in human oesophageal tissues and investigated the cellular impact of EPLIN-α on oesophageal cancer cells.

MATERIALS AND METHODS

Expression of the EPLIN-α transcript in human oesophageal tissues (tumour, paratumour and normal) was determined using the Quantitative Polymerase Chain Reaction (Q-PCR) method. In vitro models, including invasion, cellular migration (Electrical Cell substrate Impedance Sensing based method), cell growth and matrix adhesion assays were employed in order to assess the biological influence of EPLIN-α expression on KYSE150 oesophageal cancer cells.

RESULTS

EPLIN-α expression was lower in tumour tissues compared to normal tissue. Grade 3-5 tumours had slightly lower levels of EPLIN-α compared with those of grade 2. Patients who died of oesophageal cancer had significantly lower levels of EPLIN-α compared to those who remained disease-free (p=0.022). Lower levels of EPLIN-α transcript were seen in advanced oesophageal cancer, including TNM stages 2 to 4. Reduced EPLIN-α expression was associated with lymphatic metastasis and local advanced T-stage cancer, including T2-T4. Forced expression of EPLIN-α in oesophageal cancer cells rendered cells less invasive and reduced their cell growth rate in vitro.

CONCLUSION

Our study suggests that EPLIN-α is expressed at lower levels in oesophageal cancer tissues. This down-regulation has a prognostic value. Together with the findings that EPLIN-α inhibits cellular growth and invasion, we conclude that EPLIN-α is a tumour suppressor of oesophageal cancer.

P4-09-20: Expression Profile of Interleukin 17B and the Receptor IL-17BR in Clinical Breast Cancer

Introduction:

Interleukin 17B (IL-17B) is a member of the interleukin 17 cytokine family. Members of this family have been implicated in conditions such as autoimmune diseases and the inflammatory response. A number of studies have examined the role of IL17A in cancer progression and angiogenesis and shown a variety of functions, both pro- and anti- tumorigenic. Currently there is little data on IL-17B and the receptor IL-17BR and their involvement in cancer progression. The current study looks at the expression profile of IL-17B and IL-17BR in a clinical breast cancer cohort.

Methods:

The expression profile of IL-17B and IL-17BR was examined in a cohort of human normal breast and breast cancer specimens (normal, n = 34; tumour, n = 109). IL-17B and IL-17BR transcript expression in the samples was analysed using Q-PCR and compared to clinical and pathological data.

Results:

Both IL-17B and IL-17BR expression seemed to correlate with NPI staging. IL-17B levels were low in patients with NPI-1 or -2 cancers (median values 3.1 and 1.1 respectively), with highest levels of IL-17B being observed in the poorer prognosis NPI-3 group (median value 206.9; p = 0.07 NPI-1 vs NPI-3 and p = 0.01 NPI-3 vs NPI-2). Similar to this IL17B levels in TNM stage 1 cancers were significantly lower than those in higher TNM stages (TNM1 median value = 0.3 vs grouped TNM234 median value 10.3, p = 0.03). IL-17BR expression also tended to increase with NPI staging (IL-17BR median expression, NPI-1 = 0.0, NPI-2 = 0.04 and NPI-3 = 1.59; NPI-1 vs NPI-3 p = 0.07). Additionally, levels of IL-17BR were found to be significantly lower in background tissue compared to cancer tissue (median values 0.00 vs 0.01 respectively, p = 0.014).

Conclusion:

IL-17BR expression seems to be higher in tumour tissue compared to normal background tissue. Additionally, expression of IL-17B and IL-17BR both appear to be associated with higher NPI stage, particularly in the poor prognostic NPI-3 group. Expression of IL-17B seems to be elevated collectively in TNM stage 2, 3 and 4 compared to the better prognostic TNM1 stage. Together the data suggests that IL-17B and IL-17BR expression may be useful molecules to identify poorer prognostic breast cancers in patients.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-09-20.

P4-09-24: Correlation of Aurora Family Member Expression with Clinical Breast Cancer Prognosis

Introduction:

Aurora-A, Aurora-B and Aurora-C are a family of protein kinases which have been identified as key regulators of the mitotic cell division process. Members of this group have been linked with pro-tumorigenic effects and have been reported as being up-regulated in certain cancers. Our current study examines the expression profile of the Aurora-A, Aurora-B and Aurora-C members in a breast cancer cohort in relation to a number of predictive factors.

Materials and Methods:

The expression of Aurora-A, Aurora-B and Aurora-C was examined in a breast cancer cohort using quantitative real time PCR (normal samples n = 34, tumour samples n = 109) and immunhistochemistry (IHC). Expression of the aurora members was related to clinical parameters such as staging and Nottingham prognostic index (NPI).

Results:

Examination of Aurora-A levels in the breast cancer cohort revealed an association of Aurora-A expression with NPI grouping. High levels of Aurora-A levels were seen in NPI-1 and NPI-2 stages (NPI-1 median = 66.0, NPI-2 median = 64.3), with expression reducing significantly at the higher NPI-3 group (NPI-3 median = 20.3; p = 0.029 vs NPI-2 and p = 0.009 vs NPI-1 respectively). Additionally, Aurora-A levels were found to be significantly lower in grade 3 cancers compared to grade 1 (median grade 1 = 86.5 vs median grade 3 levels = 52.6, p = 0.04). In contrast to this, examination of Aurora-C levels in the cohort identified a relatively low level of Aurora-C in NPI-1 and NPI-2 group (median values NPI-1 = 88, NPI-2 = 34.4) compared to a substantial increase in Aurora-C expression in NPI-3 (median value = 1602, p = 0.05 vs NPI-1 and p = 0.06 vs NPI-2). Aurora-B expression levels did not exhibit any significant differences within the breast cancer cohort.

Conclusions:

Differential expression of Aurora-A, Aurora-B and Aurora-C were observed within the breast cancer cohort. Higher Aurora-A expression was associated with low NPI groups and grades and potentially with better patient prognosis whereas lower levels were seen in the poorer prognostic NPI-3 group and higher grades. An opposite trend was seen in Aurora-C where lower levels were associated with the NPI-1 and NPI-2 groups and significantly higher levels were seen in the NPI-3 group. Aurora-B levels appeared to have no predictive function. This data suggests that together Aurora-A and Aurora-C levels, within a patient may be useful for predicting patient outcome.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-09-24.

P4-09-14: Differential Expression of the Akt1 Isoform in Mammary Ductal Carcinoma

Introduction:

AKT1 is an oncogenic protein and controls numerous cellular processes in both normal and cancerous cells. There are three isoforms, Akt1 (PKBα), Akt2 (PKBβ) and Akt3 (PKBγ). Frequently, regulation of the Akt pathway is disrupted in cancerous cells and interest within the scientific community has focused on the use of this pathway in treating cancer. However, recent studies have also implicated that Akt1 may act to limit invasive migration of breast cancer cells suggesting the potential of this isoform to have both pro- and anti- tumorigenic roles. In the current study we examined the expression profile of Akt1 in a cohort of ducal carcinoma of the breast. Methods:

Quantitative transcript analysis was used to assess the expression levels of Akt1 in a range of ductal carcinoma of the breast (n=85) and normal samples. Expression levels were used in conjunction with clinical and pathological data, as well as the clinical outcomes of the patients (median follow-up 120 months).

Results:

Expression of Akt1 levels in the mammary ductal carcinoma cohort demonstrated a lower level of transcript expression in the lower grade and stage cancers. Levels of Akt1 were found to be significantly lower in grade 1 ductal breast carcinomas compared to the combined higher grade 1 and 2 carcinomas (ductal carcinoma grade 1 median = 3.7 vs ductal carcinoma grade 2,3 median = 33.6, p = 0.01). In addition to this, median transcript levels of Akt1 were found to increase with increasing TNM stage of the ductal carcinoma (Median values of Akt1 in ductal carcinoma TNM 1 = 5.9, TNM 2 = 63.6, TNM 3 = 533 and TNM 4 = 13680). This enhanced expression of Akt1 in higher TNM stages, compared to TNM stage 1, was found to be significant in most cases (TNM1 vs TNM2, p = 0.03; TNM1 vs TNM3, p = 0.15; TNM1 vs TNM4, p = 0.03).

Conclusion:

Variable expression of Akt1 was seen throughout the mammary ductal carcinoma cohort and correlated with a number of prognostic factors. Akt1 transcript levels were found to be significantly reduced in the low grade 1 and TNM1 stages when compared to the higher grades and TNM stages. Our current data suggests that low levels of Akt1 may be associated with better clinical patient prognosis in mammary ductal carcinoma.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-09-14.

P1-01-08: Expression of Interleukin-15 (IL-15) and the IL-15 Receptor in Human Breast Cancer

Introduction: Interleukin-15 (IL15) is a cytokine that influences activation and proliferation of T-lymphocytes. IL-15 is produced in the body leukocytes such as phagocytes and in many ways has similar immunoregulatory functions to IL-2 including stimulation of NK cells and CD8(+) T cells. It has been suggested that IL-15 may increase the immunity to cancer cells and cancer cell's response to therapeutic agents. IL-15 has also been shown to be able to inhibit tumour growth in vivo. However, the expression profile of IL-15 and IL-15 receptor (IL-15) in solid tumours including human breast cancer is not clear. The present study investigated the expression profile of both IL-15 and IL-15R in human breast cancer and deduced a clinical and pathological relevance with breast cancer.

Methods: Immunohistochemical methods were used to detect IL-15 and IL-15RA in mammary tissues. IL-15 and IL-15RA transcripts were analysed using real-time quantitative PCR method. Levels of IL-15 and IL-15RA were compared in normal and tumour tissues as well as against tumour staging, nodal status, disease progression and clinical outcome after a 10-year followup.

Results: Both IL-15 and IL-15RA were detectable in mammary tissues and were seen in both epithelial cells and infiltrating cells. Node positive tumours had low levels of IL-15 compared with node negative tumours (21.7±10 vs 103±46, respectively). Late stage tumour also had lower levels of IL-15 (95±43, 31±15, 3.7±2 and 1.3±1.15 for stage I, II, III and IV tumours respectively. p=0.036 and p=0.032, stage-II and Stage-III vs stage-I). Patients with metastatic disease (10.3±3) and patients died of breast cancer related conditions (8.5±6) had markedly low levels of IL-15 when compared with those who were disease free (54.7±25). The disease free survival time for patients with low levels IL-15 was 126 (114-138, 95%CI) months, compared with 139 (131-148) months for those with high levels of IL-15. Despite the reduced expression of IL-15 in aggressive tumours, expression of IL-15 receptor, IL-15RA, did not display a significant change and failed to showed a link with nodal status, tumour staging and clinical outcome.

Conclusions: Interleukin-15, an immuoregulatory cytokine, has an aberrant expression in human breast cancer. Low levels of IL-15, but not IL-15 receptor, is associated with the aggressiveness and disease progression of breast cancer. Together with reported effect of IL-15 on NK cells and other anti-tumour lymphocytes, IL-15 appears to be a useful therapeutic option.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-01-08.

P2-05-06: Role of Repulsive Guidance Molecule b (RGMb) in HGF Mediated Angiogenesis

Introduction: Hepatocyte Growth Factor (HGF) has been widely documented as playing a key role in enhancing the aggressive nature of cancer through its ability to promote cellular processes such as migration, invasion and angiogenesis. Development of a blood supply is vital to advanced tumour growth and increased metastatic potential. In the current study we identified RGMb (DRAGON), a member of the Repulsive Guidance Molecule family, as being upregulated by HGF and assessed its potential to contribute to HGF mediated proangiogenic traits.

Methods: Expression of RGMb was identified as being upregulated in human endothelial HECV cells following 4 hour treatment with HGF (40ng/ml) using micro array analysis and Q-PCR. Subsequently, the expression of RGMb was targeted through the transfection of HECV cells with a plasmid containing a ribozyme transgene specifically targeted to RGMb. The role of RGMb in HGF mediated cellular migration and tubule formation in vitro was examined.

Results: Significant increases in RGMb expression in HECV cells were observed on the mirco-array following 4 hour treatment with HGF (P = 0.004) and this trend was also identified using Q-PCR. Transfection with the ribozyme transgene brought about substantial reductions in RGMb expression at both transcript and protein levels as assessed using RT-PCR, QPCR and Western blot analysis. Knockout of RGMb brought about a significant increase in migration rates, compared to HECV cells transfected with a closed pEF6 plasmid only (HECVpEF6), following a 90minute period (p = 0.034 at 90 minute time point vs pEF6 control). Treatment of HGF enhanced migration rates of HECV control cells with significant differences between untreated and HGF treated pEF6 cells obvious following 60 minutes (p &lt; 0.05 at 60 and 75 minutes, p = 0.002 at 90 minutes). In contrast to this, HECV cells transfected with the RGMb ribozyme transgene (HECVRGMbKO) were unaffected by HGF treatment, with no significant differences observed between treated or untreated HECVRGMbKO cells at any time points. A similar trend was observed in the angiogenic tubule formation assay, where treatment of HECVpEF6 cells with HGF could significantly enhance the levels of tubules formed (mean tubule perimeter, untreated 8087+/− 632 vs HGF treated 13131+/− 988, p = 0.001). Treatment of HECVRGMbKO cells with HGF did not significantly enhance levels of tubule formation (mean tubule perimeter, untreated 7523+/−2458 vs HGF treated 11050+/−1512, p = 0.21).

Conclusions: Targeting of RGMb in endothelial cells appears to reduce their sensitivity to the promotional effect of HGF on cell migration and tubule formation, important traits in the angiogenic cascade. Our data suggests that RGMb may be one molecule involved in the process through which HGF enhances angiogenic potential and targeting this molecule may be a useful strategy in a number of cancer types to interfere with HGF promoted angiogenesis.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-05-06.

Influence of interleukin-8 (IL-8) and IL-8 receptors on the migration of human keratinocytes, the role of PLC-γ and potential clinical implications

Interleukin (IL)-8 is a pro-inflammatory cytokine that has a direct effect on immune cells, including polymorphonuclear cells. Keratinocytes are a rich source of IL-8. However, there is little knowledge on the role of IL-8 in clinical wound healing and the direct biological effect of IL-8 on keratinocytes. In this study, the effect of recombinant human IL-8 (rhIL-8) on migration and adhesion was tested using HaCaT keratinocytes as a cell model. The cell functions were evaluated using impedance cell sensing. The expression of IL-8 receptor (IL-8R) transcripts in human skin and wounds (acute and chronic) was assessed using real-time transcript analysis. rhIL-8 significantly increased the migration of keratinocytes (3.5±0.3 for cells treated with IL-8 vs. 2.7±0.6 for controls; p=0.029). It is interesting to note that treatment of keratinocytes with IL-8 resulted in a marked shift in the responsive frequencies. IL-8 only resulted in a marginal increase in cell adhesion, which was particularly noticeable at high frequencies. The PLC-γ inhibitor completely eradicated the action of IL-8 on the migration of HaCaT cells. Using real time PCR, it was found that chronic wounds had significantly lower levels of the B form of the IL-8R (IL-8RB) (p=0.045) and marginally lower levels of the A form, IL-8RA, in comparison with acute wounds. Therefore, IL-8 has a direct and profound stimulatory effect on the migration of human keratinocytes, which is likely to occur via the PLC-γ pathway. Together with a reduced level of IL-8Rs in difficult-healing wounds, IL-8 has a clear prognostic and therapeutic value in wound healing.

Activated leukocyte cell adhesion molecule impacts on clinical wound healing and inhibits HaCaT migration

Activated leukocyte cell adhesion molecule (ALCAM) is a glycoprotein of the immunoglobulin superfamily that has been implicated in the processes of cell adhesion and migration. The current study examines the importance of ALCAM in regulating HaCaT cell growth and migration and its potential to impact on wound healing. ALCAM levels were examined in a range of clinical wound and normal skin samples using Q-PCR and immunohistochemistry. ALCAM expression was targeted in HaCaT keratinocyte cells using a hammerhead ribozyme transgene system. Subsequently, the impact of ALCAM suppression on HaCaT migration and growth was assessed. ALCAM protein was detected mainly in keratinocytes. ALCAM transcript levels were found to be significantly higher in the non-healed chronic wound samples compared with healed samples (P = 0·026). In addition, targeting of ALCAM in HaCaT cells brought about a substantial increase in cellular migration and growth compared with HaCaT control cells.Our results suggest that ALCAM plays an important role in the migration of HaCaT keratinocyte cells. The data also suggests that higher levels of ALCAM may impair healing in chronic wounds. The impact of ALCAM in wound healing may thus be somewhat due to its impact on cell migration and growth.

Knockdown of human antigen R reduces the growth and invasion of breast cancer cells in vitro and affects expression of cyclin D1 and MMP-9

HuR, a ubiquitously expressed member of the Hu family, selectively binds and stabilizes ARE-containing mRNAs encoding proto-oncogenes, cell cycle regulators, cytokines and growth factors. The role of HuR and its cellular function in breast cancer remains unclear. This study aimed to provide new insights into the implication of HuR in breast cancer. We show that MCF7 and MDA-MB-231 breast cancer cells stably transfected with a hammerhead ribozyme transgene specifically targeted to HuR (MCF7HuRKO and MDA-MB-231HuRKO) have reduced HuR expression both at mRNA and protein levels. This study reveals that HuR knockdown dramatically reduced cell growth in MCF7 cells (P<0.001) and invasive properties in MDA-MB-231 cells (P<0.001). Furthermore, we report that the decreased cell growth rate in MCF7 cells is seen together with a reduction in cyclin D1 transcript and protein levels and that the change in invasiveness in MDA-MB-231 cells seems to be linked with decreased MMP-9 levels. Our study shows that targeting HuR can influence breast cancer cell growth and invasion and suggests a role for HuR in vitro in enhancing breast cancer cell growth and invasion. These changes may be facilitated through changes in the levels of cyclin D1 and MMP-9.

Aberrant expression and function of death receptor-3 and death decoy receptor-3 in human cancer

Death receptor-3 (DR3) and death decoy receptor-3 (DcR3) are both members of the tumour necrosis factor receptor (TNFR) superfamily. The TNFR superfamily contains eight death domain-containing receptors, including TNFR1 (also called DR1), Fas (also called DR2), DR3, DR4, DR5, DR6, NGFR and EDAR. Upon the binding of these receptors with their corresponding ligands, the death domain recruits various proteins that mediate both the death and proliferation of cells. Receptor function is negatively regulated by decoy receptors (DcR1, DcR2, DcR3 and OPG). DR3/DcR3 are a pair of positive and negative players with which vascular endothelial growth inhibitor (VEGI) interacts. VEGI has been suggested to be a potential tumour suppressor. The inhibitory effects of VEGI on cancer are manifested in three main areas: a direct effect on cancer cells, an anti-angiogenic effect on endothelial cells, and the stimulation of dendritic cell maturation. A recent study indicated that DR3 may be a new receptor for E-selectin, which has been reported to be associated with cancer metastasis. DcR3 is a soluble receptor, highly expressed in various tumours, which lacks an apparent transmembrane segment, prevents cytokine response through ligand binding and neutralization, and is an inhibitor of apoptosis. DcR3 serves as a decoy receptor for FasL, LIGHT and VEGI. The cytokine LIGHT activates various anti-tumour functions and is expected to be a promising candidate for cancer therapy. Certain tumours may escape FasL-dependent immune-cytotoxic attack by expressing DcR3, which blocks FasL function. DR3/DcR3 play profound roles in regulating cell death and proliferation in cancer. The present review briefly discusses DR3/DcR3 and attempts to elucidate the role of these negative and positive players in cancer.

Type II transmembrane serine protease (TTSP) deregulation in cancer

The Type II transmembrane serine proteases (TTSP) are a relatively newly identified family of proteolytic enzymes that have become the subject of intense scrutiny in the field of cancer research. Advances in genome screening technology have enabled the identification of putative members and the further characterization of existing members. The TTSPs are involved in a diverse range of physiological functions and new roles continue to be discovered. A large majority of these proteases appear to play crucial roles in the development of disease, especially cancer development and progression. This review presents the current knowledge of the biological role of those TTSPs that have been identified in the development and progression of human cancers.

Expression of death decoy receptor-3 (DcR3) in human breast cancer and its functional effects on breast cancer cells in vitro

BACKGROUND

Death Decoy Receptor-3 (DcR3), otherwise known as tumour necrosis factor receptor superfamily member 6b, is suggested to be involved in the progression and immune evasion of malignant tumours. Its ligands include FASL and LIGHT (Tumour necrosis factor ligand superfamily member 14). DcR3 has been found to be amplified in certain solid tumours. However, its role in breast tumours remains unclear. In the present study, we examined the role played by DcR3 in MCF7 and MDA-MB-231 cell lines.

MATERIALS AND METHODS

The expression of DcR3 was examined in MCF7 and MDA-MB-231 cell lines using immunocytochemical staining and RT-PCR. Anti-DcR3 hammerhead ribozyme transgenes were constructed and transfected into cells to create DcR3 knock-down cell sublines. The biological impact of modifying DcR3 expression in breast cancer cells was evaluated using a variety of in vitro assays, including growth, adhesion, migration and invasion models.

RESULTS

MCF7 and MDA-MB-231 cells, usually expressing DcR3, were transfected with the anti-DcR3 ribozyme transgene. Stable transfectants containing the DcR3 ribozyme transgene (MCF7DcR3KO, MDA-MB-231DcR3KO) displayed a reduction of DcR3 expression at mRNA and protein levels. DcR3 knockdown in MCF7 cells was found to significantly reduce invasive capacity compared to pEF6 control cell lines (30.78 +/- 6.40 vs.151.67 +/- 17.67 P < 0.001). The rate of migration in MCF7DcR3KO was significantly lower than MCF7pEF6 (P < 0.001). In contrast, no such significant differences was seen between MDA-MB-231DcR3KO and MDA-MB-231pEF6.

CONCLUSION

Suppressing DcR3 expression was found to have an inhibitory effect on cellular invasion and migration in MCF7 breast cancer cells. This suggests that the invasion and migration capacity of this breast cancer cell line may, at least partly, depend on DcR3. DcR3 may be regarded as a negative regulator for aggressiveness during the development and progression of certain types of breast cancer.

Prognostic value of the human antigen R (HuR) in human breast cancer: high level predicts a favourable prognosis

BACKGROUND

The role of human antigen R (HuR) and its prognostic value in breast cancer is currently only partially understood. This study aimed to determine the levels of expression of HuR in breast cancer and assess its prognostic value.

MATERIALS AND METHODS

HuR expression levels were assessed in a cohort of human breast cancer specimens and cell lines using both quantitative and qualitative analysis along with immunohistochemical techniques and the results were compared to the patient details.

RESULTS

Immunohistochemical staining revealed a weak HuR staining pattern in breast tumour sections compared to the intense epithelial staining of the normal breast tissues. The levels of HuR transcripts were lower in the more advanced TNM4 and TNM3, poor outcome NPI-2 (Nottingham Prognostic Index) and NPI-3 and node-positive tumours compared with the early stage TNM2 and TNM1, NPI-1, and node-negative tumours, although these values did not reach statistical significance. The patients with metastasis, those who died of breast cancer and those with bone metastasis had significantly decreased levels of HuR transcripts, (p=0.031, p=0.018 or p=0.038 respectively) compared to the disease-free patients. The patients with poor prognosis, including those with metastasis and those who died of breast cancer, had a significantly lower level of HuR transcripts compared to the disease-free patients (p=0.021). High levels of HuR correlated with longer overall survival, although the values did not reach statistical significance (p=0.06).

CONCLUSION

While no significant association of the levels of HuR expression with pathological status of breast cancer is reported, HuR may represent a prognostic factor in human breast cancer, as patients expressing high levels of HuR have a favourable prognosis, and the prognostic role of HuR for breast cancer metastasis, particularly bone metastasis is supported.

Abstract P1-02-05: EPLIN? Can Negatively Impact on Angiogenesis and Is Associated with ERK Signalling

Background: EPLIN (epithelial protein lost in neoplasm) is a cytoskeletal associated protein involved in regulating actin dynamics and cell motility. EPLIN expression is frequently lost in cells as they progress to a cancer state and this loss may account for enhanced cancer cell motility. EPLIN has also been shown to be lost in clinical breast cancer, which is associated with patients clinical outcome. Recently, EPLIN has been linked to ERK signalling. This study examined the potential of EPLIN to influence the angiogenesis process and its links to ERK in endothelial cells Methods: Over-expression of EPLIN α was achieved through transfection of the vascular endothelial cell, HECV, with a mammalian expression construct containing the full coding sequence of EPLINα. Enhanced levels of EPLINα were verified through RT-PCR, Q-PCR and Western blot analysis before assessing the angiogenic potential of control and transfected cells using angiogenesis and cell migration models. Treatment of transfected and control cells with ERK inhibitor was used to assess the potential interaction between EPLINα and ERK in endothelial cells. Results: Substantial enhancement in EPLINα expression was seen in transfected cells compared to control cells at both transcript and protein level. Over-expression of EPLINα in HECV endothelial cells resulted in a reduced capacity, compared to control, of these cells to form tubule like structures in an in vitro angiogenesis tubule formation assay (6566 +/− 856µm tubule perimeter of control cells vs 2881 +/− 546µm EPLINα overexpressing HECV cells, p = 0.007). This was seen together with a reduced cell migration following overexpression of EPLINα in the cells. Treatment of control cells with ERK inhibitor significantly reduced tubule formation (3537 +/− 277µm tubule perimeter of ERK inhibitor treated control cells vs 6566 +/− 856µm total perimeter of untreated control cells, p = 0.01), however treatment of HECV cells transfected with EPLINα expression construct caused tubule formation levels to return to control levels (6566 +/− 856µm tubule perimeter of untreated control cells vs 5326 +/− 784µm tubule perimeter of ERK inhibitor treated EPLINα overexpressing HECV cells, p = 0.317).

Discussion: EPLINα can negatively influence tubule formation in vitro and thus may impact on the angiogenesis process. Furthermore, its impact on tubule formation appears to be linked to ERK signalling. Together, this study suggests a role for EPLINα in angiogenesis, which may be linked with ERK signalling.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-02-05.

Abstract P5-05-11: The Cellular Impact of HuR (Human (Hu) Antigen R) in Breast Cancer Cells on the Growth and Invasion In Vitro and the Expression of Cyclin D1 and MMP-9

Introduction: HuR, a ubiquitously expressed member of the Hu family, selectively binds and stabilizes ARE-containing mRNAs encoding proto-oncogenes, cell cycle regulators, cytokines and growth factors. The role of HuR and its cellular function in breast cancer remains unclear. In the present study, we aimed to provide new insights into the molecular and cellular implication of HuR in breast cancer.

Materials and methods. We first constructed a set of anti-HuR ribozyme transgenes that targeted human HuR. Breast cancer cells were transfected with the transgene, in order to establish new sublines with HuR expression knocked down. Cell growth and invasiveness were investigated using in vitro cell models. The expression of cyclin-D1 and MMP2 were determined using immunocytochemistry, Western blotting and polymerase chain reaction.

Results: Here, we show that MCF7 and MDA-MB-231 cells breast cancer cells stability transfected with a hammerhead ribozyme transgene specifically targeted to HuR (MCF7HuRKO and MDA-MB-231HuRKO) have a reduction in HuR expression both at mRNA and protein levels. Using these new sublines of breast cancer cells, the in vitro growth was evaluated. We showed that that HuR knockdown dramatically reduced cell growth in MCF7 cells (P &lt; 0.001) and to a lesser degree reduced that in MDA MB 231 cells. We further demonstrated that reduction of HuR in MDA MB 231 cells (MDA-MB-231HuRKO) resulted in a significant reduction of the in vitro invasiveness in MDA-MB-231 cells (P &lt; 0.001), although the same failed to occur to MCF-7 cells. Furthermore, we found that the decreased cell growth rate in MCF7 cells following HuR knockdown was seen together with a reduction in cyclin D1 transcript and protein levels. It was also interest to observe that the change in invasiveness in MDA-MB-231 cells after HuR knockdown was accompanied by a decrease in MMP-9 levels.

Conclusion: Our study shows that targeting HuR can influences breast cancer cell growth and invasion and suggests a role for HuR in vitro in enhancing breast cancer cell growth and invasion. These changes may be facilitated through changes in the level of cyclin D1 and MMP-9.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-05-11.

Abstract P1-02-04: The Influence of Matriptase-2 on Angiogenesis and Tumour Growth In Vivo

Background: Metastasis is a key part of cancer progression and angiogenesis plays a large role in the ability of cancer cells to spread around the body and in the progressive growth of the primary tumour. Matriptase-2 is a cell surface serine protease believed to have implications in cancer metastasis. The current study aims to assess the importance of matriptase-2 in angiogenesis and tumour growth, using in vitro and in vivo models. Methods: Matriptase-2 was over-expressed in the HECV endothelial cell line, previously displaying minimal matriptase-2 expression, through the transfection of a mammalian expression construct containing the full coding sequence for matriptase-2. Following verification of forced expression, the cellular effects of matriptase-2 were examined using a number of in vitro cell models. The effect of matriptase-2 over-expression was also examined in in vivo mouse models by co-delivery of endothelial cells and tumour cells.

Results: Matriptase-2 significantly reduced the motility (46.47±16.18 vs 10.93±2.80 p=&lt;0.01) of the HECV cells and their ability to form tubule structures (23841.60±744.75 vs 9817.80±933.85 p=0.01) in an in vitro angiogenesis Matrigel tubule formation model. Matriptase-2 was found to have no significant effect on the growth (691.52±100.17 vs 763.50±91.43 p=0.110) and cell-matrix adhesion of the HECV cells (64.20±8.70 vs 57.42±4.50 p=0.530). However, the in vivo studies showed a reduction in tumour growth and development following co-injection of cancer cells with endothelial cells over-expressing matriptase-2 compared to co-injection with control endothelial cells. The sizes of tumours in two tumour models were: 70.99±19.52mm3 for tumour cells with control endothelial cells vs 0.17±0.10 mm3 for tumours with Matriptase-2 over-expression endothelial cells, p=&lt;0.01; and 80.41±18.31 mm3 vs 43.12±20.33 mm3 p=0.08, in the other tumour model.

Conclusion: Matriptase-2 appears to negatively influence angiogenesis through its inhibitory effect on endothelial cell motility and tubule formation. This is corroborated by the reduction of tumour growth, in vivo. Together this data suggests that matriptase-2 has an important role in the control of angiogenesis and tumour development.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-02-04.

HuR, a key post-transcriptional regulator, and its implication in progression of breast cancer

HuR, an ubiquitously expressed member of the Hu family, selectively binds and stabilizes ARE-containing mRNAs encoding proto-oncogenes, cell cycle regulators, cytokines and growth factors. The mechanism of HuR stabilization on target mRNAs is believed to be mediated through competition with destabilizing ARE-BPs. HuR is mainly localized within the cell nucleus and the nucleo-cytoplasmic shuttling of HuR is generally assumed as the initial and critical step of its stabilizing effects. A number of signaling pathways are believed to be involved in HuR shuttling. Due to the pivotal role played by HuR in stabilizing the mRNA of key factors or cytokines involved in carcinogenesis and subsequent progression, its implication and therapeutic potential in cancer have been investigated intensively since its discovery in 1996. This review discusses the role of HuR in the stabilization of key mRNAs and it's the nucleo-cytoplasmic shuttling. The review also covers the current knowledge of HuR's role in carcinogenesis, particularly its involvement in breast cancer, and the feasibility of using HuR as a therapeutic target for the treatment of breast cancer.

The impact of EPLINα (Epithelial protein lost in neoplasm) on endothelial cells, angiogenesis and tumorigenesis

BACKGROUND

EPLIN (epithelial protein lost in neoplasm) is a cytoskeletal associated protein involved in the regulation of actin dynamics and subsequently in cell motility. EPLIN expression is frequently reduced in a variety of cancer cells and tissues and this loss may account for increased invasive traits in cancer cells. The current study aimed to assess the role of EPLIN in endothelial cells and the angiogenic process.

METHODS

EPLINα expression was enhanced in HECV endothelial cells through transfection with a pEF6 expression plasmid containing the full coding sequence of EPLINα. The impact of EPLINα on HECV cells was then assessed using a range of in vitro and in vivo models.

RESULTS

transfection and over-expression of HECV cells with EPLINα expression plasmid resulted in a significant reduction in cell-matrix adhesion (P = 0.003), the rate of migration (P = 0.009) and tubule formation (P = 0.007) and also enhanced paxillin staining compared to transfection controls. Additionally, MDA-MB-231 breast cancer cells co-injected with HECV(EPLIN exp) cells developed at a slower rate than those co-injected with HECV(pEF6) cells (day 26, P = 0.05; day 33, P = 0.065, overall deviation over time P < 0.001). Treatment of HECV(EPLIN exp) cells with ERK inhibitor could rescue HECV cells from the inhibitory effect of EPLINα over-expression on tubule formation, returning these cells to control levels.

CONCLUSIONS

EPLINα over-expression can regulate HECV cell motility, matrix adhesion and tubule formation in vitro and slow in vivo tumour formation, suggesting an anti-angiogenic role for EPLINα. Extracellular signal-regulated kinase (ERK) also appears to be linked to the ability of EPLINα to inhibit tubule formation in vitro.