Downregulation of EphA1 in colorectal carcinomas correlates with invasion and metastasis

Immunohistochemical expression of ephrin receptors in neuroendocrine neoplasms: a case-series of gastroenteropancreatic neuroendocrine neoplasms and a systematic review of the literature

PURPOSE

Erythropoietin-producing hepatocellular (EPH) receptors are the largest known family of tyrosine kinases receptors (TKR) in humans, implicated in cell proliferation, adhesion, migration, tumor angiogenesis, invasion and metastasis. The aim of the present study is to assess the expression of EPHs in neuroendocrine neoplasms (NENs).

METHODS

Immunohistochemical staining of specimens of 30 patients with gastroenteropancreatic and lung NENs was performed for EPH-A1, EPH-A2, EPH-A4, EPH-A5 protein expression, in addition to ki-67 multiplication index and programmed death-ligand 1. Additionally, we performed a systematic review of the available literature in three different databases reporting on the expression of EPH in all neuroendocrine neoplasms.

RESULTS

Positive expression was seen in 16/19 (84%) specimens for EPH-A1, 15/23 (65%) for EPH-A2, 21/24 (88%) for EPH-A4, 24/26 (92%) for EPH-A5. EPH-A1 was expressed in 9/9 pancreatic, 3/4 small intestine, but not in one lung NEN, EPH-A2 in 5/10 pancreatic, 3/4 small intestine and lung, and in one of each of gastric, appendix, colorectal, and cervical NENs, respectively. EPH-A4 showed positive expression in 9/11 pancreatic, 4/4 small intestine, 3/3 lung specimens and EPH-A5 in 10/11, 4/4 and 4/4, respectively. Data retrieved from the systematic review of the literature in combination with the data from the present study are suggestive of a frequent EPH expression in pituitary, thyroid, lung and gastroenteropancreatic NENs, yet, with varying expressions of the single receptor subtypes.

CONCLUSION

EPHs may have a role in NEN tumorigenesis, prognosis as well as a role in the evolving molecular-targeted therapies.

Potential role of the Eph/ephrin system in colorectal cancer: emerging druggable molecular targets

The Eph/ephrin system regulates many developmental processes and adult tissue homeostasis. In colorectal cancer (CRC), it is involved in different processes including tumorigenesis, tumor angiogenesis, metastasis development, and cancer stem cell regeneration. However, conflicting data regarding Eph receptors in CRC, especially in its putative role as an oncogene or a suppressor gene, make the precise role of Eph-ephrin interaction confusing in CRC development. In this review, we provide an overview of the literature and highlight evidence that collaborates with these ambiguous roles of the Eph/ephrin system in CRC, as well as the molecular findings that represent promising therapeutic targets.

Expression of cancer stem cell markers CD24, EPHA1 and CD9 and their correlation with clinical outcome in epithelial ovarian tumours

BACKGROUND

There has been variability between laboratories in the identification of cancer stem cells (CSCs) markers for epithelial ovarian cancer (EOC). We have evaluated three new surface markers for EOC to identify CSCs precisely.

METHODS

Three new putative CSCs specific surface markers CD9, CD24 and EPHA1 identified by a bioinformatics approach were evaluated in normal ovary, fallopian tube and ovarian tumours.

RESULTS

The expression of CD9 alone was observed in normal ovarian surface epithelium and fallopian tube whereas CD24 and EPHA1 were not expressed (n= 5). CD24 was expressed in all tumours (N= 101) while CD9 and EPHA1 were expressed in 89 and 71 tumours, respectively. The statistical analysis showed significant correlation of the stage of the disease (p< 0.0001), type of surgery (p< 0.0001) and residual disease (p< 0.0001) with overall survival. Although expression of CD9, CD24 and EPHA1 was observed in the majority of tumours there was no significant correlation with outcome. In patients who underwent primary surgery, increased expression of CD24 significantly correlated with poor survival. The expression of CD24 was significantly reduced (p< 0.002) upon analysis of paired sections from patients prior to surgery and at interval debulking surgery (n= 16).

CONCLUSION

These findings suggest that overexpression of these new markers may be useful in identifying and targeting ovarian CSCs and CD24 may be a putative CSCs marker in ovarian cancer.

The Expression Profile and Prognostic Values of EPHA Family Members in Breast Cancer

BACKGROUND

EphAs are a class of ephrin receptors that belong to the membrane-bound receptor tyrosine kinases group. Accumulating experimental evidence has shown that the EphA family is involved in tumor progression, namely in cell proliferation, invasiveness, and metastasis. EphAs are a promising target for anticancer therapy. However, their role in breast cancer (BC) is still not well understood.

MATERIALS AND METHODS

We used a series of bioinformatic approaches to analyze the expression of the EphA family members and investigate their prognostic value in BC.

RESULTS

Lower expression levels of EphA2, EphA3, EphA4, EphA5, and EphA7 and higher expression levels of EphA10 were found in BC tissues compared to those in normal tissues. The expression levels of the EphA family genes were correlated with molecular subtyping but not with tumor stage. High expression levels of most EphAs indicated a better prognosis in BC.

CONCLUSIONS

This study suggested that EphA2, EphA3, EphA4, and EphA5 can act as tumor-inhibiting factors as well as biomarkers for the prognosis of BC.

Ephrin Receptors (Eph): EphA1, EphA5, and EphA7 Expression in Uveal Melanoma-Associations with Clinical Parameters and Patient Survival

Uveal melanoma is the most common primary intraocular malignancy in adults. The development of distant metastases is associated with a poor prognosis. Ephrine receptors (Eph) are the largest subpopulation of tyrosine kinase receptors. They play an important role in processes related to the formation and progression of cancer. The aim of the study was to evaluate the expression of ephrin receptors EphA1, EphA5, and EphA7 in uveal melanoma and its associations with clinicopathological parameters, overall survival, and disease-free survival. The study included 94 previously untreated patients who underwent enucleation due to uveal melanoma. High expression of EphA1 was positively correlated with a smaller tumor size, less frequent extra-scleral extension, lower mitotic activity, and more frequent vitreous hemorrhage. High expression of EphA5 was associated with less frequent chromosome 3 loss, absence of distant metastases, and more frequent vitreous hemorrhage. High expression of EphA7 was associated with a more frequent primary tumor location in the posterior pole. High EphA5 expression was associated with longer overall survival time. The above findings indicate that high expression of EphA1 and EphA5 can be considered a beneficial prognostic factor in uveal melanoma.

Automatic Detection Method for Cancer Cell Nucleus Image Based on Deep-Learning Analysis and Color Layer Signature Analysis Algorithm

Exploring strategies to treat cancer has always been an aim of medical researchers. One of the available strategies is to use targeted therapy drugs to make the chromosomes in cancer cells unstable such that cell death can be induced, and the elimination of highly proliferative cancer cells can be achieved. Studies have reported that the mitotic defects and micronuclei in cancer cells can be used as biomarkers to evaluate the instability of the chromosomes. Researchers use these two biomarkers to assess the effects of drugs on eliminating cancer cells. However, manual work is required to count the number of cells exhibiting mitotic defects and micronuclei either directly from the viewing window of a microscope or from an image, which is tedious and creates errors. Therefore, this study aims to detect cells with mitotic defects and micronuclei by applying an approach that can automatically count the targets. This approach integrates the application of a convolutional neural network for normal cell identification and the proposed color layer signature analysis (CLSA) to spot cells with mitotic defects and micronuclei. This approach provides a method for researchers to detect colon cancer cells in an accurate and time-efficient manner, thereby decreasing errors and the processing time. The following sections will illustrate the methodology and workflow design of this study, as well as explain the practicality of the experimental comparisons and the results that were used to validate the practicality of this algorithm.

Tumor angiogenesis: causes, consequences, challenges and opportunities

Tumor vascularization occurs through several distinct biological processes, which not only vary between tumor type and anatomic location, but also occur simultaneously within the same cancer tissue. These processes are orchestrated by a range of secreted factors and signaling pathways and can involve participation of non-endothelial cells, such as progenitors or cancer stem cells. Anti-angiogenic therapies using either antibodies or tyrosine kinase inhibitors have been approved to treat several types of cancer. However, the benefit of treatment has so far been modest, some patients not responding at all and others acquiring resistance. It is becoming increasingly clear that blocking tumors from accessing the circulation is not an easy task to accomplish. Tumor vessel functionality and gene expression often differ vastly when comparing different cancer subtypes, and vessel phenotype can be markedly heterogeneous within a single tumor. Here, we summarize the current understanding of cellular and molecular mechanisms involved in tumor angiogenesis and discuss challenges and opportunities associated with vascular targeting.

A Tyrosine Kinase Expression Signature Predicts the Post-Operative Clinical Outcome in Triple Negative Breast Cancers

Triple negative breast cancer (TNBC) represent 15% of breast cancers. Histoclinical features and marketed prognostic gene expression signatures (GES) failed to identify good- and poor-prognosis patients. Tyrosine kinases (TK) represent potential prognostic and/or therapeutic targets for TNBC. We sought to define a prognostic TK GES in a large series of TNBC. mRNA expression and histoclinical data of 6379 early BCs were collected from 16 datasets. We searched for a TK-based GES associated with disease-free survival (DFS) and tested its robustness in an independent validation set. A total of 1226 samples were TNBC. In the learning set of samples (N = 825), we identified a 13-TK GES associated with DFS. This GES was associated with cell proliferation and immune response. In multivariate analysis, it outperformed the previously published GESs and classical prognostic factors in the validation set (N = 401), in which the patients classified as "low-risk" had a 73% 5-year DFS versus 53% for "high-risk" patients (p = 1.85 × 10-3). The generation of 100,000 random 13-gene signatures by a resampling scheme showed the non-random nature of our classifier, which was also prognostic for overall survival in multivariate analysis. We identified a robust and non-random 13-TK GES that separated TNBC into subgroups of different prognosis. Clinical and functional validations are warranted.

Differential Expression Patterns of Eph Receptors and Ephrin Ligands in Human Cancers

Eph receptors constitute the largest family of receptor tyrosine kinases, which are activated by ephrin ligands that either are anchored to the membrane or contain a transmembrane domain. These molecules play important roles in the development of multicellular organisms, and the physiological functions of these receptor-ligand pairs have been extensively documented in axon guidance, neuronal development, vascular patterning, and inflammation during tissue injury. The recognition that aberrant regulation and expression of these molecules lead to alterations in proliferative, migratory, and invasive potential of a variety of human cancers has made them potential targets for cancer therapeutics. We present here the involvement of Eph receptors and ephrin ligands in lung carcinoma, breast carcinoma, prostate carcinoma, colorectal carcinoma, glioblastoma, and medulloblastoma. The aberrations in their abundances are described in the context of multiple signaling pathways, and differential expression is suggested as the mechanism underlying tumorigenesis.

Decreased Eph receptor‑A1 expression is related to grade in ovarian serous carcinoma

Eph receptor‑A1 (EphA1) was the first member of the erythropoietin producing hepatocellular carcinoma (Eph) family of receptor tyrosine kinases. Although the roles of EphA1 in the tumorigenesis of various human cancers have been investigated, few studies have focused on ovarian carcinoma. The present study aimed to explore the profile of EphA1 expression in ovarian carcinomas, to analyzed the association between EphA1 expression and clinicopathologic parameters, and to investigate the roles of overexpressed EphA1 in ovarian cancer cells. EphA1 protein was detected in ovarian cancer cell lines and in a set of formalin‑fixed tissues, including normal fallopian tube, ovarian benign serous cystadenoma, borderline serous tumors and serous carcinoma. Ovarian cancer cell lines HO8910 and A2780 were transiently transfected with EphA1‑pCMV6‑GFP plasmid, and the proliferation and apoptosis of cells were measured. The association between EphA1 expression and clinicopathological parameters was statistically analyzed. EphA1 expression was negative in HO8910 and weakly positive in A2780 cells. The proliferation rate was significantly reduced in ovarian cancer cells after transfection with EphA1 plasmid compared with cells transfected with mock plasmid or untreated cells, but no obvious alteration in apoptosis was detected among these groups. EphA1 expression was positively detected in all normal fallopian tubes (10/10, 100%) and ovarian benign serous cystadenomas (12/12, 100%) as well as in some borderline serous tumors (9/15, 60%) and ovarian serous carcinomas (33/76, 43.42%). EphA1 expression was associated with grade of ovarian serous carcinomas, with loss of EphA1 more often observed in high‑grade tumors (P=0.016) and high Ki67 index tumors (P=0.007). These data suggest that EphA1 might be a useful marker for distinguishing low grade from high‑grade ovarian serous carcinoma.

A review on Eph/ephrin, angiogenesis and lymphangiogenesis in gastric, colorectal and pancreatic cancers

Erythroprotein-producing human hepatocellular carcinoma receptors (Eph receptors) compose a subfamily of transmembrane protein-tyrosine kinases receptors that takes part in numerous physiological and pathological processes. Eph family receptor-interacting proteins (Ephrins) are ligands for those receptors. Eph/ephrin system is responsible for the cytoskeleton activity, cell adhesion, intercellular connection, cellular shape as well as cell motility. It affects neuron development and functioning, bone and glucose homeostasis, immune system and correct function of enterocytes. Moreover Eph/ephrin system is one of the crucial ones in angiogenesis and lymphangiogenesis. With such a wide range of impact it is clear that disturbed function of this system leads to pathology. Eph/ephrin system is involved in carcinogenesis and cancer progression. Although the idea of participation of ephrin in carcinogenesis is obvious, the exact way remains unclear because of complex bi-directional signaling and cross-talks with other pathways. Further studies are necessary to find a new target for treatment.

Mapping hyper-susceptibility to colitis-associated colorectal cancer in FVB/NJ mice

Inbred strains of mice differ in susceptibility to colitis-associated colorectal cancer (CA-CRC). We tested 10 inbred strains of mice for their response to azoxymethane/dextran sulfate sodium-induced CA-CRC and identified a bimodal inter-strain distribution pattern when tumor multiplicity was used as a phenotypic marker of susceptibility. The FVB/NJ strain was particularly susceptible showing a higher tumor burden than any other susceptible strains (12.5-week post-treatment initiation). FVB/NJ hyper-susceptibility was detected as early as 8-week post-treatment initiation with FVB/NJ mice developing 5.5-fold more tumors than susceptible A/J or resistant B6 control mice. Linkage analysis by whole genome scan in informative (FVB/NJ×C3H/HeJ)F2 mice identified a novel susceptibility locus designated as C olon c ancer s usceptibility 6 (Ccs6) on proximal mouse chromosome 6. When gender was used as a covariate, a LOD score of 5.4 was computed with the peak marker being positioned at rs13478727, 43.8 Mbp. Mice homozygous for FVB/NJ alleles at this locus had increased tumor multiplicity compared to homozygous C3H/HeJ mice. Positional candidates in this region of chromosome 6 were analyzed with respect to a possible role in carcinogenesis and a role in inflammatory response using a new epigenetic gene scoring tool (Myeloid Inflammation Score).

Dexamethasone Regulates EphA5, a Potential Inhibitory Factor with Osteogenic Capability of Human Bone Marrow Stromal Cells

We previously demonstrated the importance of quality management procedures for the handling of human bone marrow stromal cells (hBMSCs) and provided evidence for the existence of osteogenic inhibitor molecules in BMSCs. One candidate inhibitor is the ephrin type-A receptor 5 (EphA5), which is expressed in hBMSCs and upregulated during long-term culture. In this study, forced expression of EphA5 diminished the expression of osteoblast phenotypic markers. Downregulation of endogenous EphA5 by dexamethasone treatment promoted osteoblast marker expression. EphA5 could be involved in the normal growth regulation of BMSCs and could be a potential marker for replicative senescence. Although Eph forward signaling stimulated by ephrin-B-Fc promoted the expression of ALP mRNA in BMSCs, exogenous addition of EphA5-Fc did not affect the ALP level. The mechanism underlying the silencing of EphA5 in early cultures remains unclear. EphA5 promoter was barely methylated in hBMSCs while histone deacetylation could partially suppress EphA5 expression in early-passage cultures. In repeatedly passaged cultures, the upregulation of EphA5 independent of methylation could competitively inhibit osteogenic signal transduction pathways such as EphB forward signaling. Elucidation of the potential inhibitory function of EphA5 in hBMSCs may provide an alternative approach for lineage differentiation in cell therapy strategies and regenerative medicine.

Mutational analysis of genes coding for cell surface proteins in colorectal cancer cell lines reveal novel altered pathways, druggable mutations and mutated epitopes for targeted therapy

We carried out a mutational analysis of 3,594 genes coding for cell surface proteins (Surfaceome) in 23 colorectal cancer cell lines, searching for new altered pathways, druggable mutations and mutated epitopes for targeted therapy in colorectal cancer. A total of 3,944 somatic non-synonymous substitutions and 595 InDels, occurring in 2,061 (57%) Surfaceome genes were catalogued. We identified 48 genes not previously described as mutated in colorectal tumors in the TCGA database, including genes that are mutated and expressed in >10% of the cell lines (SEMA4C, FGFRL1, PKD1, FAM38A, WDR81, TMEM136, SLC36A1, SLC26A6, IGFLR1). Analysis of these genes uncovered important roles for FGF and SEMA4 signaling in colorectal cancer with possible therapeutic implications. We also found that cell lines express on average 11 druggable mutations, including frequent mutations (>20%) in the receptor tyrosine kinases AXL and EPHA2, which have not been previously considered as potential targets for colorectal cancer. Finally, we identified 82 cell surface mutated epitopes, however expression of only 30% of these epitopes was detected in our cell lines. Notwithstanding, 92% of these epitopes were expressed in cell lines with the mutator phenotype, opening new venues for the use of "general" immune checkpoint drugs in this subset of patients.

EphrinB1 expression is dysregulated and promotes oncogenic signaling in medulloblastoma

Eph receptors and ephrin ligands are master regulators of oncogenic signaling required for proliferation, migration, and metastasis. Yet, Eph/ephrin expression and activity in medulloblastoma (MB), the most common malignant brain tumor of childhood, remains poorly defined. We hypothesized that Eph/ephrins are differentially expressed by sonic hedgehog (SHH) and non-SHH MB and that specific members contribute to the aggressive phenotype. Affymetrix gene expression profiling of 29 childhood MB, separated into SHH (N = 11) and non-SHH (N = 18), was performed followed by protein validation of selected Eph/ephrins in another 60 MB and two MB cell lines (DAOY, D556). Functional assays were performed using MB cells overexpressing or deleted for selected ephrins. We found EPHB4 and EFNA4 almost exclusively expressed by SHH MB, whereas EPHA2, EPHA8, EFNA1 and EFNA3 are predominantly expressed by non-SHH MB. The remaining family members, except EFNB1, are ubiquitously expressed by over 70-90 % MB, irrespective of subgroup. EFNB1 is the only member differentially expressed by 28 % of SHH and non-SHH MB. Corresponding protein expression for EphB/ephrinB1 and B2 was validated in MB. Only ephrinB2 was also detected in fetal cerebellum, indicating that EphB/ephrinB1 expression is MB-specific. EphrinB1 immunopositivity localizes to tumor cells within MB with the highest proliferative index. EphrinB1 overexpression promotes EphB activation, alters F-actin distribution and morphology, decreases adhesion, and significantly promotes proliferation. Either silencing or overexpression of ephrinB1 impairs migration. These results indicate that EphrinB1 is uniquely dysregulated in MB and promotes oncogenic responses in MB cells, implicating ephrinB1 as a potential target.

Lack of ephrin receptor A1 is a favorable independent prognostic factor in clear cell renal cell carcinoma

The EPH receptor tyrosine kinases and their cell-bound ligands, the ephrins, have been shown to be associated with cancer development and progression. In this study, mRNA and protein expression of the receptors EPHA1 and EPHA2 as well as of their ligand EFNA1 and their prognostic relevance in clear cell renal cell carcinoma was evaluated. Gene expression was measured in 75 cryo-preserved primary tumors and matched non-malignant renal specimens by quantitative PCR. Protein expression was analyzed by immunohistochemistry on tissue microarrays comprising non-malignant, primary tumors and metastatic renal tissues of 241 patients. Gene and protein expression of all three factors was altered in tumor specimens with EPHA1 and EPHA2 being generally diminished in tumors compared to normal renal tissue, whereas EFNA1 was commonly elevated. A positive EPHA1 and EPHA2 protein staining as well as a low EFNA1 protein level were significantly linked to more aggressive tumor features, but only a positive EPHA1 immunoreactivity was significantly associated with poor survival. In subgroup analyses, EPHA1 and EPHA2 protein levels were significantly higher in metastatic than in primary lesions. Patients with EPHA1/EPHA2-positive tumors or with tumors with positive EPHA1 and low EFNA1 immunoreactivity had the shortest survival rates compared to the respective other combinations. In a multivariate model, EPHA1 was an independent prognostic marker for different survival endpoints. In conclusion, an impaired EPH-ephrin signaling could contribute to the pathogenesis and progression of clear cell renal cell carcinoma.

Sinomenine decreases MyD88 expression and improves inflammation-induced joint damage progression and symptoms in rat adjuvant-induced arthritis

Sinomenine (SIN) is the active principle of the Chinese medical plant Sinomenium acutum which is widely used for the treatment of rheumatoid arthritis (RA) in China. Recently, several groups indicated that myeloid differentiation primary response protein 88 (MyD88) might be associated with disease progression of RA. Here, we observed the effect of SIN on MyD88 expression and showed its therapeutic role in RA. First, immunohistochemical staining in clinical specimens showed that MyD88 was mainly located in characteristic pathological structures of RA synovial tissues. Second, we found that MyD88 was overexpressed in the synovial tissues of the rats with adjuvant-induced arthritis (AIA). Treatment with SIN markedly decreased the expression of MyD88 in AIA rats. Finally, we provided evidences that SIN suppressed inflammation response and inflammation-induced joint destructive progression and arthritis symptoms in AIA rats. Therefore, SIN is an effective therapeutic agent for RA. Targeting MyD88 signaling may provide new methods for the treatment of RA.

Ephrin (Eph) receptor A1, A4, A5 and A7 expression in human non-small cell lung carcinoma: associations with clinicopathological parameters, tumor proliferative capacity and patients' survival

Background

Ephrin (Eph) receptors are frequently overexpressed in a wide variety of human malignant tumors, being associated with tumor growth, invasion, metastasis and angiogenesis. The present study aimed to evaluate the clinical significance of EphA1, A4, A5 and A7 protein expression in non-small cell lung carcinoma (NSCLC).

Methods

EphA1, A4, A5 and A7 protein expression was assessed immunohistochemically in tissue microarrays of 88 surgically resected NSCLC and was analyzed in relation with clinicopathological characteristics and patients’ survival.

Results

Elevated EphA4 expression was significantly associated with low histopathological stage and presence of inflammation (p = 0.047 and p = 0.026, respectively). Elevated EphA7 expression was significantly associated with older patients’ age, presence of fibrosis and smaller tumor size (p = 0.036, p = 0.029 and p = 0.018, respectively). EphA1, A5 and A7 expression were positively associated with tumor proliferative capacity (p = 0.047, p = 0.002 and p = 0.046, respectively). Elevated EphA4, A5 and A7 expression were identified as predictors of favourable patients’ survival at both univariate (Log-rank test, 0 = 0.019, p = 0.006 and p = 0.012, respectively) and multivariate levels (Cox-regression analysis, p = 0.029, p = 0.068 and p = 0.044, respectively).

Conclusions

The present study supported evidence that Ephs may be involved in lung cancer progression, reinforcing their utility as clinical biomarkers for patients’ management and prognosis, as also as potential targets for future therapeutic interventions.

After repeated division, bone marrow stromal cells express inhibitory factors with osteogenic capabilities, and EphA5 is a primary candidate

The differentiation capability of human bone marrow stromal cells (hBMSCs) is thought to deteriorate over multiple doubling processes. To clarify the deterioration mechanisms, the multilineage differentiation capabilities of short- and long-term passaged BMSCs were compared. Predictably, long-term passaged BMSCs showed reduced differentiation capacities compared to short-term passaged cells. Furthermore, a non-human primate heterotopic bone formation model demonstrated that long-term passaged BMSCs have bone formation capabilities but also exert inhibitory effects on bone formation. This finding indicated that long-term passaged BMSCs express higher levels of inhibitory factors than short-term passaged BMSCs do. Co-culture assays of short- and long-term passaged BMSCs suggested that the inhibitory signals required cell-cell contact and would therefore be expressed on the cell membrane. A microarray analysis of BMSCs identified ephrin type-A receptor 5 (EphA5) as an inhibitory factor candidate. Quantitative PCR revealed that among all members of the ephrin and Eph receptor families, only the expression of EphA5 was increased by BMSC proliferation. A gene knockdown analysis using siRNAs demonstrated that knockdown of EphA5 gene expression in long-term passaged BMSCs led to an increase in ALP mRNA expression. These results indicate that EphA5 may be a negative regulator of bone formation. A better understanding of the roles of the ephrin and Eph receptor families in hBMSCs may lead to alternative approaches for manipulating hBMSC fate. In addition, this avenue of discovery may provide new therapeutic targets and quality-control markers of the osteogenic differentiation capabilities of hBMSCs.

Ephrin receptor (Eph) -A1, -A2, -A4 and -A7 expression in mobile tongue squamous cell carcinoma: associations with clinicopathological parameters and patients survival

Ephrin receptors (Ephs) are frequently overexpressed in a wide variety of human malignant tumors, being associated with tumor growth, invasion, metastasis and angiogenesis. The present study aimed to evaluate the clinical significance of Eph-A1, -A2, -A4 and -A7 protein expression in mobile tongue squamous cell carcinoma (SCC). Eph-A1, -A2, -A4 and -A7 protein expression was assessed immunohistochemically on 37 mobile tongue SCC tissue samples and was analyzed in relation with clinicopathological characteristics, overall and disease-free patients' survival. All the examined mobile tongue SCC cases were found positive for Eph-A1, -A2, -A4 and -A7. Significant associations were noted between high Eph-A1, -A4 and -A7 expression and absence of lymph node metastases (p = 0.0263, p = 0.0461 and p = 0.0461, respectively). High Eph-A1, -A2 and -A7 expression was significantly more frequently observed in patients presenting absence of vascular invasion (p = 0.0444), dense stromal inflammatory reaction (p = 0.0063) and female gender (p = 0.0327), respectively. Mobile tongue SCC patients with high Eph-A7 expression presented longer overall and disease-free survival compared to those with low Eph-A7 expression (log-rank test, p = 0.0093 and p = 0.0164, respectively). In multivariate analysis, Eph-A7 expression was identified as independent prognostic factor of overall survival (Cox-regression analysis, p = 0.0426). The present study supported evidence that Ephs may participate in the malignant transformation of mobile tongue SCC, reinforcing their utility as clinical markers for patients' management and prognosis, as also as targets for potential therapeutic intervention in tongue chemoprevention.

[Eph family receptors as therapeutic targets]

Anti-angiogenic therapy is currently a commonly accepted and rapidly developing approach in oncology and other pathologies linked to aberrant neovascularization. Discovery and validation of additional molecular targets in angiogenesis is needed due to the limitations of the existing clinical therapeutics inhibiting activity of vascular endothelial growth factor (VEGF) and its receptors. A brief review of normal and pathological biological functions of the Eph family of receptor tyrosine kinases and their ephrin ligands is presented, and the approaches to developing therapeutics with anti- and pro-angiogenic and anti-tumor activity based on selective molecular modulation of Eph-ephrin signaling pairs are discussed. Functional roles of Eph-kinases and ephrins in such mechanisms of cancerogenesis as cell proliferation and invasion are also addressed.

High expression of EphA1 in esophageal squamous cell carcinoma is associated with lymph node metastasis and advanced disease

Eph receptors play important roles in the development of cancer. The present study aimed to investigate the expression of EphA1 and its clinicopathologic significance in esophageal squamous cell carcinoma (ESCC). The expression levels of the EphA1 transcript and protein were compared between ESCC and matched normal mucosa in the same patient. High expression levels of the EphA1 transcript and protein were detected in 25.6% (21/82) and 23.2% (19/82) of tumors compared with matched normal mucosa. The up-regulation of EphA1 transcript in tumors was positively associated with differentiation (p = 0.002), disease stage (p = 0.034), and lymph node metastasis (p = 0.042). Increased expression of EphA1 protein in tumors was more often observed in patients with well-differentiated tumors (p = 0.004), lymph node metastasis (p = 0.028), and advanced tumor stage (p = 0.008). EphA1 protein expression was detected in intraepithelial neoplasias as well. Decreased expression of EphA1 protein was detected in 65.2% (15/23) of samples with low-grade neoplasia and in 85.3% (8/15) of samples with high-grade intraepithelial neoplasia. Increased staining of EphA1 protein was not detected in low-grade intraepithelial neoplasia samples, but was detected in 21.3% (2/15) of high-grade intraepithelial neoplasia samples. Taken together, our results show that EphA1 appears to be a differentiation marker for esophageal squamous cells, and its increased expression is positively associated with lymph node metastasis and advanced disease stage.

Eph-dependent cell-cell adhesion and segregation in development and cancer

Numerous studies attest to essential roles for Eph receptors and their ephrin ligands in controlling cell positioning and tissue patterning during normal and oncogenic development. These studies suggest multiple, sometimes contradictory, functions of Eph-ephrin signalling, which under different conditions can promote either spreading and cell-cell adhesion or cytoskeletal collapse, cell rounding, de-adhesion and cell-cell segregation. A principle determinant of the balance between these two opposing responses is the degree of receptor/ligand clustering and activation. This equilibrium is likely altered in cancers and modulated by somatic mutations of key Eph family members that have emerged as candidate cancer markers in recent profiling studies. In addition, cross-talk amongst Ephs and with other signalling pathways significantly modulates cell-cell adhesion, both between and within Eph- and ephrin-expressing cell populations. This review summarises our current understanding of how Eph receptors control cell adhesion and morphology, and presents examples demonstrating the importance of these events in normal development and cancer.

Effects of macrophage metalloelastase on the basic fibroblast growth factor expression and tumor angiogenesis in murine colon cancer

BACKGROUND AND AIM

Previous studies have shown that overexpression of macrophage metalloelastase (MME) suppresses tumor growth in mice. The purpose of this study was to investigate the effects of MME on basic fibroblast growth factor (bFGF) expression and tumor angiogenesis in murine colon cancer.

METHODS

Murine CT-26 colon cancer cells stably transfected with MME were inoculated subcutaneously. Reverse-transcriptase polymerase chain reaction (RT-PCR), immunoblotting, and immunohistochemistry were used to explore the bFGF mRNA and protein expression. Immunohistochemical staining of CD34 was used to measure the microvessel density (MVD).

RESULTS

bFGF mRNA levels in tumor tissues of CT-26-EGFP and nontransfected cells were respectively 2.7-fold (0.56 ± 0.063 vs. 0.21 ± 0.042) and 2.5-fold (0.53 ± 0.066 vs. 0.21 ± 0.042) higher than that in tumors of CT-26-EGFP-MME cells (p < 0.01). bFGF protein levels exhibited a similar trend. Tumors of CT-26-EGFP-MME cells demonstrated a lower microvessel density (9.35 ± 2.79) than control tumors of CT-26-EGFP cells (22.85 ± 3.80) and nontransfected cells (23.45 ± 4.49) (p < 0.001).

CONCLUSIONS

We found that expression of MME inversely correlates with the expression of bFGF and tumor angiogenesis in a model of murine colon cancer. These data indicate that manipulation of MME expression could be a novel modality approach to colon cancer therapy.

Clinical relevance of Ephs and ephrins in cancer: lessons from breast, colorectal, and lung cancer profiling

Pre-clinical studies provide compelling evidence that members of the Eph family of receptor tyrosine kinases and their ephrin ligands promote tumor growth, invasion and metastasis, and neovascularization. Tumor suppressive roles have also been reported for the receptors, and ligand-dependent versus ligand-independent signaling has emerged as one key mechanism underlying tumor suppressive function as opposed to oncogenic effects. Determining how these observations relate to clinical outcome is a crucial step for translating the biological and mechanistic data into new molecularly targeted therapies. Expression profiling in human patient samples bridges this gap and provides valuable clinical relevance to laboratory observations. In addition to analyses performed using privately assembled patient tumor samples, publically available microarray datasets and tissue microarrays linked to clinical data have emerged as tractable tools for addressing the clinical relevance of specific molecules and families of related molecules. This review summarizes the clinical relevance of specific Eph and ephrin molecules in human breast, colorectal, and lung cancers.

De novo expression of EphA2 in osteosarcoma modulates activation of the mitogenic signalling pathway

AIMS

In osteosarcoma patients the development of metastases, often to the lungs, is the most frequent cause of death. The aim of this study was to elucidate the molecular mechanisms governing osteosarcoma development and dissemination and, thereby, to identify possible novel drug targets for improved treatment.

METHODS AND RESULTS

Osteosarcoma samples were characterized using genome-wide microarrays: increased expression of the EphA2 receptor and its ligand EFNA1 was detected. In addition, increased expression of EFNB1, EFNB3 and EphA3 was suggested. Immunohistochemistry revealed an absence of EphA2 in normal bone, and de novo expression in osteosarcomas. EFNA1 was expressed in normal bone, but was significantly elevated in tumours. Further in vitro investigations on the functional role of EphA2 and EFNA1 showed that EFNA1 ligand binding induced increased tyrosine phosphorylation, receptor degradation and downstream mitogen-activated protein kinase (MAPK) activation. Interference with the MAPK pathway unravelled a potential autoregulatory loop governing mainly EFNA1 expression via the same pathway.

CONCLUSION

Upregulation and de novo expression of ephrins in osteosarcomas are involved in oncogenic signalling and thus might stimulate osteosarcoma metastasis.

EPH-EPHRIN in human gastrointestinal cancers

Ever since its discovery two decades ago, the erythropoietin-producing hepatoma (EPH)-EPHRIN system has been shown to play multifaceted roles in human gastroenterological cancer as well as neurodevelopment. Over-expression, amplification and point mutations have been found in many human cancers and many investigators have shown correlations between these up-regulations and tumor angiogenesis. Thus, the genes in this family are considered to be potential targets of cancer therapy. On the other hand, the down-regulation of some members as a result of epigenetic changes has also been reported in some cancers. Furthermore, the correlation between altered expressions and clinical prognosis seems to be inconclusive. A huge amount of protein-protein interaction studies on the EPH-EPHRIN system have provided a basic scheme for signal transductions, especially bi-directional signaling involving EPH-ERPHRIN molecules at the cell membrane. This information also provides a manipulative strategy for harnessing the actions of these molecules. In this review, we summarize the known alterations of EPH-EPHRIN genes in human tumors of the esophagus, stomach, colorectum, liver and pancreas and present the perspective that the EPH-EPHRIN system could be a potential target of cancer therapy.

Frequent epigenetic inactivation of deleted in lung and esophageal cancer 1 gene by promoter methylation in non-small-cell lung cancer

BACKGROUND

Deleted in lung and esophageal cancer 1 (DLEC1) gene was a new candidate tumor suppressor gene. We determined the expression level and methylation status of DLEC1 in non-small-cell lung cancer (NSCLC), and the DLEC1 methylation in plasma DNA as a biomarker for NSCLC was further evaluated.

PATIENTS AND METHODS

The study population enrolled 78 paired NSCLC specimens and adjacent normal tissues and 25 benign pulmonary lesions. Meanwhile, corresponding plasma samples were collected. Methylation-specific polymerase chain reaction (PCR) was used to detect the DLEC1 methylation status. DLEC1 gene expression was determined by reverse transcriptase PCR and immunohistochemistry.

RESULTS

Hypermethylation of DLEC1 was found in 41% (32/78) of NSCLC tissues, which was significantly higher than that of adjacent normal tissues (3.8%; 3/78) and benign lesions (0/25; P < .001). Also, DLEC1 methylation was closely correlated with loss of expression, and treatment with 5-aza-2'-deoxycytidine induced DLEC1 restoration in A549 and SPC-A1 cell lines. Furthermore, DLEC1 hypermethylation was associated with advanced stage (P = .011) and lymph node metastasis (P = .019). Methylated DLEC1 was detected in 35.9% (28/78) of plasma samples from NSCLC patients and only 2% (1/50) in cancer-free controls, and the concordance of DLEC1 methylation status in plasmas and corresponding tumor tissues was good.

CONCLUSION

DLEC1 is silenced by promoter methylation in NSCLC specimens and is widely expressed in adjacent normal tissues and benign control samples. The high detection rate of methylated DLEC1 in plasma DNA further indicates its potential diagnostic and prognosis values in NSCLC.

Eph receptors and ephrin ligands: important players in angiogenesis and tumor angiogenesis

Eph receptors and their ephrin ligands were identified in the late 1980's. Subsequently, they were linked to different physiological and pathophysiological processes like embryonic development, angiogenesis, and tumorigenesis. In this regard, recent work focused on the distribution and effects of Eph receptors and ephrins on tumor cells and tumor microenvironment. The purpose of this review is to outline the role of these molecules in physiological angiogenesis and pathophysiological tumor angiogenesis. Furthermore, novel therapeutical approaches are discussed as Eph receptors and ephrins represent attractive targets for antiangiogenic therapy.

SIRT1 histone deacetylase expression is associated with microsatellite instability and CpG island methylator phenotype in colorectal cancer

The class III histone deacetylase SIRT1 (sir2) is important in epigenetic gene silencing. Inhibition of SIRT1 reactivates silenced genes, suggesting a possible therapeutic approach of targeted reversal of aberrantly silenced genes. In addition, SIRT1 may be involved in the well-known link between obesity, cellular energy balance and cancer. However, a comprehensive study of SIRT1 using human cancer tissue with clinical outcome data is currently lacking, and its prognostic significance is uncertain. Using the database of 485 colorectal cancers in two independent prospective cohort studies, we detected SIRT1 overexpression in 180 (37%) tumors by immunohistochemistry. We examined its relationship to the CpG island methylator phenotype (CIMP), related molecular events, clinical features including body mass index, and patient survival. We quantified DNA methylation in eight CIMP-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1) and eight other CpG islands (CHFR, HIC1, IGFBP3, MGMT, MINT1, MINT31, p14, and WRN) by MethyLight. SIRT1 overexpression was associated with CIMP-high (> or =6 of 8 methylated CIMP-specific promoters, P=0.002) and microsatellite instability (MSI)-high phenotype (P<0.0001). In both univariate and multivariate analyses, SIRT1 overexpression was significantly associated with the CIMP-high MSI-high phenotype (multivariate odds ratio, 3.20; 95% confidence interval, 1.35-7.59; P=0.008). In addition, mucinous component (P=0.01), high tumor grade (P=0.02), and fatty acid synthase overexpression (P=0.04) were significantly associated with SIRT positivity in multivariate analysis. SIRT1 was not significantly related with age, sex, tumor location, stage, signet ring cells, cyclooxygenase-2 (COX-2), LINE-1 hypomethylation, KRAS, BRAF, BMI, PIK3CA, HDAC, p53, beta-catenin, COX-2, or patient prognosis. In conclusion, SIRT1 expression is associated with CIMP-high MSI-high colon cancer, suggesting involvement of SIRT1 in gene silencing in this unique tumor subtype.