Gene Summary

Gene:EPHA2; EPH receptor A2
Summary:This gene belongs to the ephrin receptor subfamily of the protein-tyrosine kinase family. EPH and EPH-related receptors have been implicated in mediating developmental events, particularly in the nervous system. Receptors in the EPH subfamily typically have a single kinase domain and an extracellular region containing a Cys-rich domain and 2 fibronectin type III repeats. The ephrin receptors are divided into 2 groups based on the similarity of their extracellular domain sequences and their affinities for binding ephrin-A and ephrin-B ligands. This gene encodes a protein that binds ephrin-A ligands. Mutations in this gene are the cause of certain genetically-related cataract disorders.[provided by RefSeq, May 2010]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:ephrin type-A receptor 2
Source:NCBIAccessed: 01 September, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 01 September 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 01 September, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: EPHA2 (cancer-related)

Yeo C, Lee HJ, Lee EO
Serum promotes vasculogenic mimicry through the EphA2/VE-cadherin/AKT pathway in PC-3 human prostate cancer cells.
Life Sci. 2019; 221:267-273 [PubMed] Related Publications
AIMS: Serum is widely used for in vitro cell culture of eukaryotic cells. Although serum is well known to affect various biological activities in cancer cells, its effect in vasculogenic mimicry (VM) is not yet fully defined. Thus, this study investigated the role of serum in VM in human prostate cancer (PCa) PC-3 cells.
MAIN METHODS: Invasion assay and 3D culture VM tube formation assay are performed. VM-related molecules are checked by western blot and reverse transcriptase-polymerase chain reaction. Nuclear twist is detected by confocal after twist-FITC/DAPI double staining.
KEY FINDINGS: Serum dramatically induced not only invasion but also VM. Serum increased the phosphorylation of erythropoietin-producing hepatocellular A2 (EphA2) without affecting EphA2 expression. Both the protein and mRNA expression levels of vascular endothelial cadherin (VE-cadherin) are up-regulated by serum. Twist expression was increased in the nucleus by serum. Serum activated AKT through phosphorylation, despite the unchanged AKT expression. Serum caused an increase in matrix metalloproteinase-2 (MMP-2) and laminin subunit 5 gamma-2 (LAMC2) protein expressions. Wortmannin, a phosphoinositide-3-kinase inhibitor, significantly decreased serum-induced invasion and VM.
SIGNIFICANCE: These results demonstrated that serum activates EphA2 and up-regulates twist/VE-cadherin, which in turn activate AKT that up-regulates MMP-2 and LAMC2, thereby inducing the invasion and VM of human PCa PC-3 cells.

Du J, He Y, Wu W, et al.
Targeting EphA2 with miR-124 mediates Erlotinib resistance in K-RAS mutated pancreatic cancer.
J Pharm Pharmacol. 2019; 71(2):196-205 [PubMed] Related Publications
OBJECTIVES: Chemotheraputic drug resistance is a critical factor associated with the poor survival in advanced/metastatic pancreatic cancer (PC) patients.
METHODS: Human pancreatic cell lines Capan-1 and BXPC-3 were cultured with different concentrations of erlotinib (0, 10, 50, and 100 μm) for 48 h. The relative cell viability and apoptosis was detected using MTT assays and flow cytometry apoptosis analysis, respectively. Transfection of pcDNA-EphA2, si-EphA2 and miR-124 mimic/inhibitor was used to modulate the intracellular level of EphA2 and miR-124. The interaction between miR-124 and the 3'UTR of EphA2 was explored using dual luciferase reporter assay.
KEY FINDINGS: Compared with BXPC-3 cells, Capan-1 cells showed resistance to differential concentration treatment of erlotinib. The expression of EphA-2 was significantly increased and the expression of miR-124 was significantly decreased in Capan-1 cells. Overexpressing EphA2 induced resistance of BXPC-3 cells to erlotinib treatment. And EphA2 was identified as a novel target gene for miR-124. MiR-124 overexpression was able to sensitize the response of Capan-1 cells to erlotinib through inhibiting EphA2. Furthermore, both miR-124 overexpression and EphA2 inhibition sensitized Capan-1 cells to erlotinib in xenograft model.
CONCLUSIONS: Our study demonstrated that EphA2 rescued by miR-124 downregulation conferred the erlotinib resistance of PC cell Capan-1 with K-RAS mutation.

Torres-Adorno AM, Vitrac H, Qi Y, et al.
Eicosapentaenoic acid in combination with EPHA2 inhibition shows efficacy in preclinical models of triple-negative breast cancer by disrupting cellular cholesterol efflux.
Oncogene. 2019; 38(12):2135-2150 [PubMed] Free Access to Full Article Related Publications
Triple-negative breast cancer (TNBC), the most aggressive breast cancer subtype, currently lacks effective targeted therapy options. Eicosapentaenoic acid (EPA), an omega-3 fatty acid and constituent of fish oil, is a common supplement with anti-inflammatory properties. Although it is not a mainstream treatment, several preclinical studies have demonstrated that EPA exerts anti-tumor activity in breast cancer. However, against solid tumors, EPA as a monotherapy is clinically ineffective; thus, we sought to develop a novel targeted drug combination to bolster its therapeutic action against TNBC. Using a high-throughput functional siRNA screen, we identified Ephrin type-A receptor 2 (EPHA2), an oncogenic cell-surface receptor tyrosine kinase, as a therapeutic target that sensitizes TNBC cells to EPA. EPHA2 expression was uniquely elevated in TNBC cell lines and patient tumors. In independent functional expression studies in TNBC models, EPHA2 gene-silencing combined with EPA significantly reduced cell growth and enhanced apoptosis compared with monotherapies, both in vitro and in vivo. EPHA2-specific inhibitors similarly enhanced the therapeutic action of EPA. Finally, we identified that therapy-mediated apoptosis was attributed to a lethal increase in cancer cell membrane polarity due to ABCA1 inhibition and subsequent dysregulation of cholesterol homeostasis. This study provides new molecular and preclinical evidence to support a clinical evaluation of EPA combined with EPHA2 inhibition in patients with TNBC.

Nordor AV, Bellet D, Siwo GH
Cancer-malaria: hidden connections.
Open Biol. 2018; 8(10) [PubMed] Free Access to Full Article Related Publications
Cancer and malaria exemplify two maladies historically assigned to separated research spaces. Cancer, on the one hand, ranks among the top priorities in the research agenda of developed countries. Its rise is mostly explained by the ageing of these populations and linked to environment and lifestyle. Malaria, on the other hand, represents a major health burden for developing countries in the Southern Hemisphere. These two diseases also belong to separate fields of medicine: non-communicable diseases for cancer and communicable diseases for malaria.

Blumenthal MJ, Schutz C, Meintjes G, et al.
EPHA2 sequence variants are associated with susceptibility to Kaposi's sarcoma-associated herpesvirus infection and Kaposi's sarcoma prevalence in HIV-infected patients.
Cancer Epidemiol. 2018; 56:133-139 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
BACKGROUND: To determine if variations exist in the KSHV host receptor EPHA2's coding region that affect KSHV infectivity and/or KS prevalence among South African HIV-infected patients.
METHODS: A retrospective candidate gene association study was performed on 150 patients which were randomly selected from a total of 756 HIV-infected patients and grouped according to their KS status and KSHV serodiagnosis; namely group 1: KS
RESULTS: 100% (95% CI 92.9-100%) of the KS positive patients, and 31.6% (95% CI 28.3-35.1%) of the KS negative patients were found to be KSHV seropositive. Aggregate variation across the entire EPHA2 coding region identified an association with KS (OR = 6.6 (95% CI 2.8, 15.9), p = 2.2 × 10
CONCLUSIONS: Variations in the KSHV entry receptor gene EPHA2 affected susceptibility to KSHV infection and KS development in a South African HIV-infected patient cohort.

Haghiralsadat F, Amoabediny G, Naderinezhad S, et al.
Codelivery of doxorubicin and JIP1 siRNA with novel EphA2-targeted PEGylated cationic nanoliposomes to overcome osteosarcoma multidrug resistance.
Int J Nanomedicine. 2018; 13:3853-3866 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Purpose: Osteosarcoma (OS) mostly affects children and young adults, and has only a 20%-30% 5-year survival rate when metastasized. We aimed to create dual-targeted (extracellular against EphA2 and intracellular against JNK-interacting protein 1 [JIP1]), doxorubicin (DOX)-loaded liposomes to treat OS metastatic disease.
Materials and methods: Cationic liposomes contained
Results: Characteristics assessment showed that 1) size of the bilayered particles was 109 nm; 2) DOX loading efficiency was 87%; 3) siRNA could be successfully loaded at a liposome:siRNA ratio of >24:1; and 4) the zeta potential was 18.47 mV. Tumor-mimicking pH conditions exhibited 80% siRNA and 50.7% DOX sustained release from the particles. Stability studies ensured the protection of siRNA against degradation in serum. OS cell lines showed increased and more pericellular/nuclear localizations when using targeted vesicles. Nontargeted and targeted codelivery caused 70.5% and 78.6% cytotoxicity in OS cells, respectively (free DOX: 50%). Targeted codelivery resulted in 42% reduction in the siRNA target, JIP1 mRNA, and 46% decrease in JIP1 levels.
Conclusion: Our dual-targeted, DOX-loaded liposomes enhance toxicity toward OS cells and may be effective for the treatment of metastatic OS.

Jang J, Son J, Park E, et al.
Discovery of a Highly Potent and Broadly Effective Epidermal Growth Factor Receptor and HER2 Exon 20 Insertion Mutant Inhibitor.
Angew Chem Int Ed Engl. 2018; 57(36):11629-11633 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Exon 20 insertion (Ex20Ins) mutations are the third most prevalent epidermal growth factor receptor (EGFR) activating mutation and the most prevalent HER2 mutation in non-small cell lung cancer (NSCLC). Novel therapeutics for the patients with Ex20Ins mutations are urgently needed, due to their poor responses to the currently approved EGFR and HER2 inhibitors. Here we report the discovery of highly potent and broadly effective EGFR and HER2 Ex20Ins mutant inhibitors. The co-crystal structure of compound 1 b in complex with wild type EGFR clearly revealed an additional hydrophobic interaction of 4-fluorobenzene ring within a deep hydrophobic pocket, which has not been widely exploited in the development of EGFR and HER2 inhibitors. As compared with afatinib, compound 1 a exhibited superior inhibition of proliferation and signaling pathways in Ba/F3 cells harboring either EGFR or HER2 Ex20Ins mutations, and in the EGFR P772_H773insPNP patient-derived lung cancer cell line DFCI127. Our study identifies promising strategies for development of EGFR and HER2 Ex20Ins mutant inhibitors.

Wu Q, Xu L, Wang C, et al.
MicroRNA-124-3p represses cell growth and cell motility by targeting EphA2 in glioma.
Biochem Biophys Res Commun. 2018; 503(4):2436-2442 [PubMed] Related Publications
MiR-124-3p and EphA2 are aberrantly expressed in glioma tissue specimens. In the present study, we firstly investigated that miR-124-3p inhibits EphA2 expression mediated by binding its 3'-UTR to regulate the progression of human glioma. The U87MG and LN229 cells were transfected with miR-124-3p mimics and/or siRNA-EphA2, and then the role of miR-124-3p and EphA2 in the colony-formation, cell-cycle, migration and invasion of glioma cells in vitro were examined. Proteins involved in the epithelial-mesenchymal transition were examined using western blot. The results showed that miR-124-3p was significantly downregulated in glioma tissues, whereas a marked upregulation of EphA2 expression was found. Colony-formation and flow cytometry assays demonstrated that EphA2 downregulation or miR-124-3p mimics caused growth and cell-cycle inhibition in glioma. Transwell migration and invasion assays demonstrated that EphA2 downregulation or miR-124-3p mimics suppressed the migration and invasion of glioma cells. EphA2 downregulation or miR-124-3p mimics reduced the level of vimentin in U87MG and LN229 cells. In conclusion, miR-124-3p was found to suppress the growth, migration and invasion of glioma cells in vitro via EphA2. Furthermore, we validated miR-124-3p enforced its biological modulation via targeting EphA2 through the rescue experiment. Conclusively, our study proclaimed that miR-124-3p can counteract the malignant phenotypes of glioma cells by the inhibitory effect of the EphA2.

Chen M, Hu C, Guo Y, et al.
Ophiopogonin B suppresses the metastasis and angiogenesis of A549 cells in vitro and in vivo by inhibiting the EphA2/Akt signaling pathway.
Oncol Rep. 2018; 40(3):1339-1347 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Lung adenocarcinoma is the most common metastatic cancer, and is associated with high patient mortality. Therefore, investigation of anti‑metastatic treatments for lung adenocarcinoma is crucial. Ophiopogonin B (OP‑B) is a bioactive component of Radix Ophiopogon Japonicus, which is often used in Chinese traditional medicine to treat pulmonary disease. Screening of transcriptome and digital gene expression (DGE) profiling data in NSCLC cell lines showed that OP‑B regulated the epithelial‑mesenchymal transition (EMT) pathway in A549 cells. Further results showed that 10 µmol/l OP‑B downregulated EphA2 expression and phosphorylation (Ser897) in A549 cells but upregulated them in NCI‑H460 cells. Meanwhile, the Ras/ERK pathway was unaffected in A549 cells and stimulated in NCI‑H460 cells. More importantly, detection of the EMT pathway showed that OP‑B treatment increased the epithelial markers ZO‑1 and E‑cadherin and decreased the expression of the mesenchymal marker N‑cadherin and the transcriptional repressors Snail, Slug and ZEB1. Furthermore, through Transwell migration and scratch wound healing assays, we found that 10 µmol/l OP‑B significantly reduced the invasion and migration of A549 cells. In vivo, we found that 75 mg/kg OP‑B inhibited A549 cell metastasis in a pulmonary metastasis nude mouse model. In addition, we also found that 10 µmol/l OP‑B significantly inhibited tube formation in EA.hy926 cells. The expression of VEGFR2 and Tie‑2, the phosphorylation of Akt (S473) and PLC (S1248), and the levels of EphA2 and phosphorylated EphA2 (S897) were all inhibited by OP‑B in this cell line. In vivo, using a Matrigel plug assay, we found that OP‑B inhibited angiogenesis and the hemoglobin content of A549 transplanted tumors. Taken together, OP‑B inhibited the metastasis and angiogenesis of A549 cells by inhibiting EphA2/Akt and the corresponding pathway. The investigation gives new recognition to the anticancer mechanism of OP‑B in NSCLC and this compound is a promising inhibitor of metastasis and angiogenesis of lung adenocarcinoma cells.

Li G, Huang M, Cai Y, et al.
miR‑141 inhibits glioma vasculogenic mimicry by controlling EphA2 expression.
Mol Med Rep. 2018; 18(2):1395-1404 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Human glioma is a pernicious tumor from the central nervous system; it has been reported that microRNAs (miRs) may have carcinogenic or tumor suppressor effects on human glioma. The aim of the present study was to assess miR‑141 expression and functional role in human primary glioma, as well as in tumor‑derived cell lines. The expression of miR‑141 in primary human glioma tissues and cell lines was assessed by employing reverse transcription‑quantitative polymerase chain reaction. Next, its role in cellular growth, migration, invasion and vasculogenic mimicry (VM) regulation was determined using various in vitro and in vivo assays, and on the identification its target gene(s) using luciferase assays. The results demonstrated that miR‑141 expression was downregulated, and Ephrin type‑A receptor 2 (EphA2) was upregulated in the primary human gliomas and human glioma‑derived cell lines tested. In addition, a negative correlation existed between miR‑141 and EphA2 expression levels in glioma grades II, III and IV. Furthermore, exogenous miR‑141 expression resulted in decreased proliferation, migration and invasion, as well as in apoptosis and cell cycle arrest in vitro. It was also revealed that exogenous miR‑141 expression resulted in in vivo inhibition of tumor growth and inhibition of the development of VM. Finally, the present study successfully confirmed that EphA2 was a direct target of miR‑141 in glioma‑derived cells using luciferase assays. Based on these results, it was concluded that miR‑141 may regulate cell proliferation, migration, invasion and VM formation by controlling EphA2 expression; also, its target EphA2 may be a novel diagnostic/prognostic biomarker and a potential anti‑VM therapeutic target.

Taniguchi H, Baba Y, Sagiya Y, et al.
Biologic Response of Colorectal Cancer Xenograft Tumors to Sequential Treatment with Panitumumab and Bevacizumab.
Neoplasia. 2018; 20(7):668-677 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Recent studies in RAS wild-type (WT) metastatic colorectal cancer (mCRC) suggest that the survival benefits of therapy using anti-epidermal growth factor receptor (anti-EGFR) and anti-vascular endothelial growth factor (anti-VEGF) antibodies combined with chemotherapy are maximized when the anti-EGFR antibody is given as first-line, followed by subsequent anti-VEGF antibody therapy. We report reverse-translational research using LIM1215 xenografts of RAS WT mCRC to elucidate the biologic mechanisms underlying this clinical observation. Sequential administration of panitumumab then bevacizumab (PB) demonstrated a stronger tendency to inhibit tumor growth than bevacizumab then panitumumab (BP). Cell proliferation was reduced significantly with PB (P < .01) but not with BP based on Ki-67 index. Phosphoproteomic analysis demonstrated reduced phosphorylation of EGFR and EPHA2 with PB and BP compared with control. Western blotting showed reduced EPHA2 expression and S897-phosphorylation with PB; RSK phosphorylation was largely unaffected by PB but increased significantly with BP. In quantitative real-time PCR analyses, PB significantly reduced the expression of both lipogenic (FASN, MVD) and hypoxia-related (CA9, TGFBI) genes versus control. These results suggest that numerous mechanisms at the levels of gene expression, protein expression, and protein phosphorylation may explain the improved clinical activity of PB over BP in patients with RAS WT mCRC.

Zhang T, Li J, Ma X, et al.
Inhibition of HDACs-EphA2 Signaling Axis with WW437 Demonstrates Promising Preclinical Antitumor Activity in Breast Cancer.
EBioMedicine. 2018; 31:276-286 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Histone deacetylase inhibitors (HDACi) are small molecules targeting epigenetic enzymes approved for hematologic neoplasms, which have also demonstrated clinical activities in solid tumors. In our present study, we screened our internal compound library and discovered a novel HDACi, WW437, with potent anti-breast cancer ability in vitro and in vivo. WW437 significantly inhibited phosphorylated EphA2 and EphA2 expression. Further study demonstrated WW437 blocked HDACs-EphA2 signaling axis in breast cancer. In parallel, we found that EphA2 expression positively correlates with breast cancer progression; and combined use of WW437 and an EphA2 inhibitor (ALW-II-41-27) exerted more remarkable effect on breast cancer growth than either drug alone. Our findings suggested inhibition of HDACs-EphA2 signaling axis with WW437 alone or in combination with other agents may be a promising therapeutic strategy for advanced breast cancer.

Garcia-Monclús S, López-Alemany R, Almacellas-Rabaiget O, et al.
EphA2 receptor is a key player in the metastatic onset of Ewing sarcoma.
Int J Cancer. 2018; 143(5):1188-1201 [PubMed] Free Access to Full Article Related Publications
Ewing sarcoma (ES) is the second most common bone malignancy affecting children and young adults with poor prognosis due to high metastasis incidence. Our group previously described that EphA2, a tyrosine kinase receptor, promotes angiogenesis in Ewing sarcoma (ES) cells via ligand-dependent signaling. Now we wanted to explore EphA2 ligand-independent activity, controlled upon phosphorylation at S897 (p-EphA2

Inokuchi M, Nakagawa M, Baogok N, et al.
Prognostic Significance of High EphA1-4 Expression Levels in Locally Advanced Gastric Cancer.
Anticancer Res. 2018; 38(3):1685-1693 [PubMed] Related Publications
BACKGROUND/AIM: Erythropoietin-producing hepatocellular carcinoma receptor A (EphA) is associated with angiogenesis and invasive tumor progression. In this study, we evaluated the EphA1-4 expression levels in advanced gastric cancer.
PATIENTS AND METHODS: Tumor tissues obtained from 114 patients with advanced gastric adenocarcinoma who underwent gastrectomy were analyzed. In addition, the impact of EPHA 1-4 mRNA expression on survival was analyzed using the Kaplan-Meier plotter database on the website.
RESULTS: High EphA 1, 2, and 4 expression levels were significantly related to recurrence (p<0.01, p=0.04, and p<0.01). Both high EphA 1 and 4 expression levels were independent predictors of relapse-free interval (hazard ratio [HR]=2.0, p=0.03; HR=2.4, p=0.03) and disease-specific survival (HR=2.0, 95% p=0.03; HR=2.5, p=0.02) on multivariate analysis. In the Kaplan-Meier plotter database, high EPHA2 mRNA expression was significantly associated with poor survival in patients with gastric cancer (p=0.0098), and high expression levels of EPHA1 and 4 tended to be associated with poor survival (p=0.050, p=0.052).
CONCLUSION: EphA 1, 2, and 4 may play key roles in recurrence and survival in patients with advanced gastric cancer.

Huang J, He Y, Mcleod HL, et al.
miR-302b inhibits tumorigenesis by targeting EphA2 via Wnt/ β-catenin/EMT signaling cascade in gastric cancer.
BMC Cancer. 2017; 17(1):886 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: EphA2 is a crucial oncogene in gastric cancer (GC) development and metastasis, this study aims to identify microRNAs that target it and serve as key regulators of gastric carcinogenesis.
METHODS: We identified several potential microRNAs targeting EphA2 by bioinformatics websites and then analyzed the role of miR-302b in modulating EphA2 in vitro and in vivo of GC, and it's mechanism.
RESULTS: Our analysis identified miR-302b, a novel regulator of EphA2, as one of the most significantly downregulated microRNA (miRNA) in GC tissues. Overexpression of miR-302b impaired GC cell migratory and invasive properties robustly and suppressed cell proliferation by arresting cells at G0-G1 phase in vitro. miR-302b exhibited anti-tumor activity by reversing EphA2 regulation, which relayed a signaling transduction cascade that attenuated the functions of N-cadherin, β-catenin, and Snail (markers of Wnt/β-catenin and epithelial-mesenchymal transition, EMT). This modulation of EphA2 also had distinct effects on cell proliferation and migration in GC in vivo.
CONCLUSIONS: miR-302b serves as a critical suppressor of GC cell tumorigenesis and metastasis by targeting the EphA2/Wnt/β-catenin/EMT pathway.

Edwards DN, Ngwa VM, Wang S, et al.
The receptor tyrosine kinase EphA2 promotes glutamine metabolism in tumors by activating the transcriptional coactivators YAP and TAZ.
Sci Signal. 2017; 10(508) [PubMed] Free Access to Full Article Related Publications
Malignant tumors reprogram cellular metabolism to support cancer cell proliferation and survival. Although most cancers depend on a high rate of aerobic glycolysis, many cancer cells also display addiction to glutamine. Glutamine transporters and glutaminase activity are critical for glutamine metabolism in tumor cells. We found that the receptor tyrosine kinase EphA2 activated the TEAD family transcriptional coactivators YAP and TAZ (YAP/TAZ), likely in a ligand-independent manner, to promote glutamine metabolism in cells and mouse models of HER2-positive breast cancer. Overexpression of EphA2 induced the nuclear accumulation of YAP and TAZ and increased the expression of YAP/TAZ target genes. Inhibition of the GTPase Rho or the kinase ROCK abolished EphA2-dependent YAP/TAZ nuclear localization. Silencing

Azimi A, Tuominen R, Costa Svedman F, et al.
Silencing FLI or targeting CD13/ANPEP lead to dephosphorylation of EPHA2, a mediator of BRAF inhibitor resistance, and induce growth arrest or apoptosis in melanoma cells.
Cell Death Dis. 2017; 8(8):e3029 [PubMed] Free Access to Full Article Related Publications
A majority of patients with BRAF-mutated metastatic melanoma respond to therapy with BRAF inhibitors (BRAFi), but relapses are common owing to acquired resistance. To unravel BRAFi resistance mechanisms we have performed gene expression and mass spectrometry based proteome profiling of the sensitive parental A375 BRAF V600E-mutated human melanoma cell line and of daughter cell lines with induced BRAFi resistance. Increased expression of two novel resistance candidates, aminopeptidase-N (CD13/ANPEP) and ETS transcription factor FLI1 was observed in the BRAFi-resistant daughter cell lines. In addition, increased levels of the previously reported resistance mediators, receptor tyrosine kinase ephrine receptor A2 (EPHA2) and the hepatocyte growth factor receptor MET were also identified. The expression of these proteins was assessed in matched tumor samples from melanoma patients obtained before BRAFi and after disease progression. MET was overexpressed in all progression samples while the expression of the other candidates varied between the individual patients. Targeting CD13/ANPEP by a blocking antibody induced apoptosis in both parental A375- and BRAFi-resistant daughter cells as well as in melanoma cells with intrinsic BRAFi resistance and led to dephosphorylation of EPHA2 on S897, previously demonstrated to cause inhibition of the migratory capacity. AKT and RSK, both reported to induce EPHA2 S897 phosphorylation, were also dephosphorylated after inhibition of CD13/ANPEP. FLI1 silencing also caused decreases in EPHA2 S897 phosphorylation and in total MET protein expression. In addition, silencing of FLI1 sensitized the resistant cells to BRAFi. Furthermore, we show that BRAFi in combination with the multi kinase inhibitor dasatinib can abrogate BRAFi resistance and decrease both EPHA2 S897 phosphorylation and total FLI1 protein expression. This is the first report presenting CD13/ANPEP and FLI1 as important mediators of resistance to BRAF inhibition with potential as drug targets in BRAFi refractory melanoma.

Bissanum R, Lirdprapamongkol K, Svasti J, et al.
The role of WT1 isoforms in vasculogenic mimicry and metastatic potential of human triple negative breast cancer cells.
Biochem Biophys Res Commun. 2017; 494(1-2):256-262 [PubMed] Related Publications
Triple negative breast cancer (TNBC) is highly aggressive and has a few therapeutic treatments, so new targeted therapy and biomarkers are required to provide alternative choices for treating TNBC patients. Recent studies showed that vasculogenic mimicry (VM), the formation of blood channels by aggressive cancer cells that mimic endothelial cells, is a factor contributing to poor prognosis in TNBC. Wilms' tumor 1 (WT1) gene has been found to be highly expressed in TNBC, and has 4 major distinct isoforms; isoform A (-17AA/-KTS; -/-), isoform B (+17AA/-KTS; +/-), isoform C (-17AA/+KTS; -/+) and isoform D (+17AA/+KTS; +/+). The involvement of each WT1 isoform in TNBC progression remains largely unclear. In this study, WT1 isoform-overexpressing cell sublines were established from a TNBC cell line, MDA-MB-231, by stable transfection, and the aggressive behavior of the cell sublines were evaluated. Only the WT1 isoform B- and isoform C-overexpressing cell sublines showed the significant increase in VM forming capability compared to the parental cell line and other isoform cell sublines. qRT-PCR was used to explore the change in expression level of two VM-related genes, EphA2 and VE-cadherin. All WT1 isoform cell sublines showed up-regulation of EphA2 but the levels detected in the isoform B- and isoform C-cell sublines were higher than those observed in other cell sublines. In contrast, significant up-regulation of VE-cadherin was found only in isoform A- and isoform D-cell sublines. Isoform B- and isoform C-cell sublines showed higher rates of cell migration compared to those of other cell sublines, as determined by both wound healing and Transwell assays. Gelatin zymography revealed increased MMP-9 enzyme production in isoform D-cell subline compared to the parental cell line, but this change was not observed in other cell sublines. Western blot analysis showed significantly increased expression of β-catenin in isoform B- and isoform C-cell sublines, compared to parental cell line and other isoform cell sublines. In conclusion, our findings demonstrate that WT1 isoforms play different roles in modulating the VM-forming capacity and metastatic potential of TNBC cells.

Bielamowicz K, Fousek K, Byrd TT, et al.
Trivalent CAR T cells overcome interpatient antigenic variability in glioblastoma.
Neuro Oncol. 2018; 20(4):506-518 [PubMed] Free Access to Full Article Related Publications
Background: Glioblastoma (GBM) is the most common primary malignant brain cancer, and is currently incurable. Chimeric antigen receptor (CAR) T cells have shown promise in GBM treatment. While we have shown that combinatorial targeting of 2 glioma antigens offsets antigen escape and enhances T-cell effector functions, the interpatient variability in surface antigen expression between patients hinders the clinical impact of targeting 2 antigen pairs. This study addresses targeting 3 antigens using a single CAR T-cell product for broader application.
Methods: We analyzed the surface expression of 3 targetable glioma antigens (human epidermal growth factor receptor 2 [HER2], interleukin-13 receptor subunit alpha-2 [IL13Rα2], and ephrin-A2 [EphA2]) in 15 primary GBM samples. Accordingly, we created a trivalent T-cell product armed with 3 CAR molecules specific for these validated targets encoded by a single universal (U) tricistronic transgene (UCAR T cells).
Results: Our data showed that co-targeting HER2, IL13Rα2, and EphA2 could overcome interpatient variability by a tendency to capture nearly 100% of tumor cells in most tumors tested in this cohort. UCAR T cells made from GBM patients' blood uniformly expressed all 3 CAR molecules with distinct antigen specificity. UCAR T cells mediated robust immune synapses with tumor targets forming more polarized microtubule organizing centers and exhibited improved cytotoxicity and cytokine release over best monospecific and bispecific CAR T cells per patient tumor profile. Lastly, low doses of UCAR T cells controlled established autologous GBM patient derived xenografts (PDXs) and improved survival of treated animals.
Conclusion: UCAR T cells can overcome antigenic heterogeneity in GBM and lead to improved treatment outcomes.

Huang HT, Seo HS, Zhang T, et al.
MELK is not necessary for the proliferation of basal-like breast cancer cells.
Elife. 2017; 6 [PubMed] Free Access to Full Article Related Publications
Thorough preclinical target validation is essential for the success of drug discovery efforts. In this study, we combined chemical and genetic perturbants, including the development of a novel selective maternal embryonic leucine zipper kinase (MELK) inhibitor HTH-01-091, CRISPR/Cas9-mediated MELK knockout, a novel chemical-induced protein degradation strategy, RNA interference and CRISPR interference to validate MELK as a therapeutic target in basal-like breast cancers (BBC). In common culture conditions, we found that small molecule inhibition, genetic deletion, or acute depletion of MELK did not significantly affect cellular growth. This discrepancy to previous findings illuminated selectivity issues of the widely used MELK inhibitor OTSSP167, and potential off-target effects of MELK-targeting short hairpins. The different genetic and chemical tools developed here allow for the identification and validation of any causal roles MELK may play in cancer biology, which will be required to guide future MELK drug discovery efforts. Furthermore, our study provides a general framework for preclinical target validation.

Tan YC, Mirzapoiazova T, Won BM, et al.
Differential responsiveness of MET inhibition in non-small-cell lung cancer with altered CBL.
Sci Rep. 2017; 7(1):9192 [PubMed] Free Access to Full Article Related Publications
Casitas B-lineage lymphoma (CBL) is an E3 ubiquitin ligase and a molecule of adaptor that we have shown is important for non-small-cell lung cancer (NSCLC). We investigated if MET is a target of CBL and if enhanced in CBL-altered NSCLC. We showed that CBL wildtype cells have lower MET expression than CBL mutant cells. Ubiquitination of MET was also decreased in CBL mutant cells compared to wildtype cells. Mutant cells were also more sensitive to MET inhibitor SU11274 than wild-type cells. sh-RNA-mediated knockdown of CBL enhanced cell motility and colony formation in NSCLC cells, and these activities were inhibited by SU11274. Assessment of the phospho-kinome showed decreased phosphorylation of pathways involving MET, paxillin, EPHA2, and VEGFR. When CBL was knocked down in the mutant cell line H1975 (erlotinib-resistant), it became sensitive to MET inhibition. Our findings suggest that CBL status is a potential positive indicator for MET-targeted therapeutics in NSCLC.

Zanini E, Louis LS, Antony J, et al.
The Tumor-Suppressor Protein OPCML Potentiates Anti-EGFR- and Anti-HER2-Targeted Therapy in HER2-Positive Ovarian and Breast Cancer.
Mol Cancer Ther. 2017; 16(10):2246-2256 [PubMed] Related Publications
Opioid-binding protein/cell adhesion molecule-like (OPCML) is a tumor-suppressor gene that is frequently inactivated in ovarian cancer and many other cancers by somatic methylation. We have previously shown that OPCML exerts its suppressor function by negatively regulating a spectrum of receptor tyrosine kinases (RTK), such as ErbB2/HER2, FGFR1, and EphA2, thus attenuating their related downstream signaling. The physical interaction of OPCML with this defined group of RTKs is a prerequisite for their downregulation. Overexpression/gene amplification of EGFR and HER2 is a frequent event in multiple cancers, including ovarian and breast cancers. Molecular therapeutics against EGFR/HER2 or EGFR only, such as lapatinib and erlotinib, respectively, were developed to target these receptors, but resistance often occurs in relapsing cancers. Here we show that, though OPCML interacts only with HER2 and not with EGFR, the interaction of OPCML with HER2 disrupts the formation of the HER2-EGFR heterodimer, and this translates into a better response to both lapatinib and erlotinib in HER2-expressing ovarian and breast cancer cell lines. Also, we show that high OPCML expression is associated with better response to lapatinib therapy in breast cancer patients and better survival in HER2-overexpressing ovarian cancer patients, suggesting that OPCML co-therapy could be a valuable sensitizing approach to RTK inhibitors.

Ivey JW, Latouche EL, Richards ML, et al.
Enhancing Irreversible Electroporation by Manipulating Cellular Biophysics with a Molecular Adjuvant.
Biophys J. 2017; 113(2):472-480 [PubMed] Free Access to Full Article Related Publications
Pulsed electric fields applied to cells have been used as an invaluable research tool to enhance delivery of genes or other intracellular cargo, as well as for tumor treatment via electrochemotherapy or tissue ablation. These processes involve the buildup of charge across the cell membrane, with subsequent alteration of transmembrane potential that is a function of cell biophysics and geometry. For traditional electroporation parameters, larger cells experience a greater degree of membrane potential alteration. However, we have recently demonstrated that the nuclear/cytoplasm ratio (NCR), rather than cell size, is a key predictor of response for cells treated with high-frequency irreversible electroporation (IRE). In this study, we leverage a targeted molecular therapy, ephrinA1, known to markedly collapse the cytoplasm of cells expressing the EphA2 receptor, to investigate how biophysical cellular changes resulting from NCR manipulation affect the response to IRE at varying frequencies. We present evidence that the increase in the NCR mitigates the cell death response to conventional electroporation pulsed-electric fields (∼100 μs), consistent with the previously noted size dependence. However, this same molecular treatment enhanced the cell death response to high-frequency electric fields (∼1 μs). This finding demonstrates the importance of considering cellular biophysics and frequency-dependent effects in developing electroporation protocols, and our approach provides, to our knowledge, a novel and direct experimental methodology to quantify the relationship between cell morphology, pulse frequency, and electroporation response. Finally, this novel, to our knowledge, combinatorial approach may provide a paradigm to enhance in vivo tumor ablation through a molecular manipulation of cellular morphology before IRE application.

Wen Q, Chen Z, Chen Z, et al.
EphA2 affects the sensitivity of oxaliplatin by inducing EMT in oxaliplatin-resistant gastric cancer cells.
Oncotarget. 2017; 8(29):47998-48011 [PubMed] Free Access to Full Article Related Publications
Erythropoietin-producing hepatocellular receptor A2 (EphA2) is upregulated in gastric cancer tissues and cells, which is accompanied by epithelial-mesenchymal transition (EMT). The current study was designed to establish the oxaliplatin-resistant human gastric cancer cell line SGC-7901/L-OHP, to determine if EMT in these cells could be reversed, and to determine if the susceptibility of these cells to oxaliplatin was affected by silencing EphA2 expression. We found that EphA2 expression levels were upregulated in gastric cancer and associated with chemotherapy sensitivity. EphA2 and the EMT molecular markers N-cadherin and Snail were upregulated in SGC-7901/L-OHP cells, while silencing of EphA2 using small interfering RNA had the opposite effect. Moreover, silencing of EphA2 inhibited cell migration and invasion, and significantly enhanced the sensitivity of oxaliplatin-resistant gastric cancer cells to oxaliplatin. These observations demonstrate that EphA2 affects the sensitivity to oxaliplatin by inducing EMT in oxaliplatin-resistant gastric cancer cells.

Takasugi M, Okada R, Takahashi A, et al.
Small extracellular vesicles secreted from senescent cells promote cancer cell proliferation through EphA2.
Nat Commun. 2017; 8:15729 [PubMed] Free Access to Full Article Related Publications
Cellular senescence prevents the proliferation of cells at risk for neoplastic transformation. However, the altered secretome of senescent cells can promote the growth of the surrounding cancer cells. Although extracellular vesicles (EVs) have emerged as new players in intercellular communication, their role in the function of senescent cell secretome has been largely unexplored. Here, we show that exosome-like small EVs (sEVs) are important mediators of the pro-tumorigenic function of senescent cells. sEV-associated EphA2 secreted from senescent cells binds to ephrin-A1, that is, highly expressed in several types of cancer cells and promotes cell proliferation through EphA2/ephrin-A1 reverse signalling. sEV sorting of EphA2 is increased in senescent cells because of its enhanced phosphorylation resulting from oxidative inactivation of PTP1B phosphatase. Our results demonstrate a novel mechanism of reactive oxygen species (ROS)-regulated cargo sorting into sEVs, which is critical for the potentially deleterious growth-promoting effect of the senescent cell secretome.

Song W, Hwang Y, Youngblood VM, et al.
Targeting EphA2 impairs cell cycle progression and growth of basal-like/triple-negative breast cancers.
Oncogene. 2017; 36(40):5620-5630 [PubMed] Free Access to Full Article Related Publications
Basal-like/triple-negative breast cancers (TNBCs) are among the most aggressive forms of breast cancer, and disproportionally affects young premenopausal women and women of African descent. Patients with TNBC suffer a poor prognosis due in part to a lack of molecularly targeted therapies, which represents a critical barrier for effective treatment. Here, we identify EphA2 receptor tyrosine kinase as a clinically relevant target for TNBC. EphA2 expression is enriched in the basal-like molecular subtype in human breast cancers. Loss of EphA2 function in both human and genetically engineered mouse models of TNBC reduced tumor growth in culture and in vivo. Mechanistically, targeting EphA2 impaired cell cycle progression through S-phase via downregulation of c-Myc and stabilization of the cyclin-dependent kinase inhibitor p27/KIP1. A small molecule kinase inhibitor of EphA2 effectively suppressed tumor cell growth in vivo, including TNBC patient-derived xenografts. Thus, our data identify EphA2 as a novel molecular target for TNBC.

Cuyàs E, Queralt B, Martin-Castillo B, et al.
EphA2 receptor activation with ephrin-A1 ligand restores cetuximab efficacy in NRAS-mutant colorectal cancer cells.
Oncol Rep. 2017; 38(1):263-270 [PubMed] Related Publications
Patients with wild-type KRAS metastatic colorectal cancer (mCRC) that harbors NRAS activating mutations do not benefit from anti-EGFR therapies. Very little is known about oncogenic NRAS signaling driving mCRC unresponsiveness to the EGFR-directed antibody cetuximab. Using a system of paired NRAS-mutant and wild-type isogenic mCRC cell lines to explore signaling pathways engaged by the common oncogenic NRAS Q61K variant upon challenge with cetuximab, we uncovered an unexpected mechanism of resistance to cetuximab involving dysregulation of the ephrin-A1/EphA2 signaling axis. Parental NRAS+/+ cells, but not NRASQ61K/+ cells, activated the ephrin receptor ephA1 in response to cetuximab treatment. Moreover, whereas cetuximab treatment significantly downregulated EPHA2 gene expression in NRAS+/+ cells, EPHA2 expression in NRASQ61K/+ cells was refractory to cetuximab. Remarkably, pharmacologically mimicked ephrin-A1 engagement to ephA2 converted NRAS-mutant into RAS wild-type mCRC cells in terms of cetuximab efficacy. Accordingly, activation of the ephA2 receptor by bioactive recombinant human ephrin-A1/Fc-fusion protein suppressed the cetuximab-unresponsive hyperactivation of MAPK and AKT and fully restored cetuximab activity in NRAS-mutant colorectal cells. Collectively, these findings reveal that the clinical benefit of cetuximab in mCRC might necessarily involve the suppression of the ligandless oncogenic signaling of the ephA2 receptor. Hence, ligand-dependent tumor suppressor signaling using therapeutic ephA2 agonists might offer new therapeutic opportunities to clinically widen the use of cetuximab in NRAS-mutated and/or ephA2-dependent mCRC tumors.

Su SC, Lin CW, Liu YF, et al.
Exome Sequencing of Oral Squamous Cell Carcinoma Reveals Molecular Subgroups and Novel Therapeutic Opportunities.
Theranostics. 2017; 7(5):1088-1099 [PubMed] Free Access to Full Article Related Publications
Oral squamous cell carcinoma (OSCC), an epithelial malignancy affecting a variety of subsites in the oral cavity, is prevalent in Asia. The survival rate of OSCC patients has not improved over the past decades due to its heterogeneous etiology, genetic aberrations, and treatment outcomes. Improvement in therapeutic strategies and tailored treatment options is an unmet need. To unveil the mutational spectrum, whole-exome sequencing of 120 OSCC from male individuals in Taiwan was conducted. Analyzing the contributions of the five mutational signatures extracted from the dataset of somatic variations identified four groups of tumors that were significantly associated with demographic and clinical features. In addition, known (

Kosaka T, Tanizaki J, Paranal RM, et al.
Response Heterogeneity of EGFR and HER2 Exon 20 Insertions to Covalent EGFR and HER2 Inhibitors.
Cancer Res. 2017; 77(10):2712-2721 [PubMed] Free Access to Full Article Related Publications
Insertion mutations in EGFR and HER2 both occur at analogous positions in exon 20. Non-small cell lung cancer (NSCLC) patients with tumors harboring these mutations seldom achieve clinical responses to dacomitinib and afatinib, two covalent quinazoline-based inhibitors of EGFR or HER2, respectively. In this study, we investigated the effects of specific EGFR and HER2 exon 20 insertion mutations from NSCLC patients that had clinically achieved a partial response after dacomitinib treatment. We identified Gly770 as a common feature among the drug-sensitive mutations. Structural modeling suggested that this mutation may facilitate inhibitor binding to EGFR. Introduction of Gly770 into two dacomitinib-resistant EGFR exon 20 insertion mutants restored sensitivity to dacomitinib. Based on these findings, we used afatinib to treat an NSCLC patient whose tumor harbored the HER2 V777_G778insGSP mutation and achieved a durable partial response. We further identified secondary mutations in EGFR (T790M or C797S) and HER2 (C805S) that mediated acquired drug resistance in drug-sensitive EGFR or HER2 exon 20 insertion models. Overall, our findings identified a subset of EGFR and HER2 exon 20 insertion mutations that are sensitive to existing covalent quinazoline-based EGFR/HER2 inhibitors, with implications for current clinical treatment and next-generation small-molecule inhibitors.

Gundry C, Marco S, Rainero E, et al.
Phosphorylation of Rab-coupling protein by LMTK3 controls Rab14-dependent EphA2 trafficking to promote cell:cell repulsion.
Nat Commun. 2017; 8:14646 [PubMed] Free Access to Full Article Related Publications
The Rab GTPase effector, Rab-coupling protein (RCP) is known to promote invasive behaviour in vitro by controlling integrin and receptor tyrosine kinase (RTK) trafficking, but how RCP influences metastasis in vivo is unclear. Here we identify an RTK of the Eph family, EphA2, to be a cargo of an RCP-regulated endocytic pathway which controls cell:cell repulsion and metastasis in vivo. Phosphorylation of RCP at Ser

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