EphA2 inhibition suppresses proliferation of small-cell lung cancer cells through inducing cell cycle arrest

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.

LncRNA LINC00466 Promotes the Progression of Breast Cancer via miR-4731-5p/EPHA2 Pathway

BACKGROUND

Breast Cancer (BC) is a female malignancy with a high mortality rate. Novel diagnostic and prognostic biomarkers are valuable for reducing BC mortality. Our study is designed to undrape the precise role of the LINC00466/miR-4731-5p/EPHA2 axis in BC.

METHODS

The Cancer Genome Atlas (TCGA) sequencing dataset was utilized to compare the levels of LINC00466. The levels of LINC00466, miR-4731-5p, and EPHA2 were tested by qRTPCR. Cell proliferation and cycle were detected by CCK-8 assay and flow cytometer. In vivo role of LINC00466 was tested by Xenograft nude models. Binding sites were predicted by TargetScan and Starbase. The binding relationship was employed by Dual-luciferase reporter gene assay and RNA pull-down assay.

RESULTS

LINC00466 was increased in human breast cancer tissues. LINC00466 was negatively associated with miR-4731-5p and positively correlated with EPHA2 in human breast cancer tissues. Down-regulation of LINC00466 suppressed the proliferation and arrested the cell cycle of breast cancer cells, and inhibited tumor growth in vivo.

CONCLUSION

LINC00466 promoted BC development via mediating the miR-4731-5p/EPHA2 axis, which has the potential value as a promising therapeutic target in BC.

Erythropoietin-induced hepatocyte receptor A2 regulates effect of pyroptosis on gastrointestinal colorectal cancer occurrence and metastasis resistance

Erythropoietin-induced hepatocyte receptor A2 (EphA2) is a receptor tyrosine kinase that plays a key role in the development and progression of a variety of tumors. This article reviews the expression of EphA2 in gastrointestinal (GI) colorectal cancer (CRC) and its regulation of pyroptosis. Pyroptosis is a form of programmed cell death that plays an important role in tumor suppression. Studies have shown that EphA2 regulates pyrodeath through various signaling pathways, affecting the occurrence, development and metastasis of GI CRC. The overexpression of EphA2 is closely related to the aggressiveness and metastasis of GI CRC, and the inhibition of EphA2 can induce pyrodeath and improve the sensitivity of cancer cells to treatment. In addition, EphA2 regulates intercellular communication and the microenvironment through interactions with other cytokines and receptors, further influencing cancer progression. The role of EphA2 in GI CRC and its underlying mechanisms provide us with new perspectives and potential therapeutic targets, which have important implications for future cancer treatment.

Targeting the EphA2 pathway: could it be the way for bone sarcomas?

Bone sarcomas are malignant tumors of mesenchymal origin. Complete surgical resection is the cornerstone of multidisciplinary treatment. However, advanced, unresectable forms remain incurable. A crucial step towards addressing this challenge involves comprehending the molecular mechanisms underpinning tumor progression and metastasis, laying the groundwork for innovative precision medicine-based interventions. We previously showed that tyrosine kinase receptor Ephrin Type-A Receptor 2 (EphA2) is overexpressed in bone sarcomas. EphA2 is a key oncofetal protein implicated in metastasis, self-renewal, and chemoresistance. Molecular, genetic, biochemical, and pharmacological approaches have been developed to target EphA2 and its signaling pathway aiming to interfere with its tumor-promoting effects or as a carrier for drug delivery. This review synthesizes the main functions of EphA2 and their relevance in bone sarcomas, providing strategies devised to leverage this receptor for diagnostic and therapeutic purposes, with a focus on its applicability in the three most common bone sarcoma histotypes: osteosarcoma, chondrosarcoma, and Ewing sarcoma.

Targeting EphA2: a promising strategy to overcome chemoresistance and drug resistance in cancer

Erythropoietin-producing hepatocellular A2 (EphA2) is a vital member of the Eph tyrosine kinase receptor family and has been associated with developmental processes. However, it is often overexpressed in tumors and correlates with cancer progression and worse prognosis due to the activation of its noncanonical signaling pathway. Throughout cancer treatment, the emergence of drug-resistant tumor cells is relatively common. Since the early 2000s, researchers have focused on understanding the role of EphA2 in promoting drug resistance in different types of cancer, as well as finding efficient and secure EphA2 inhibitors. In this review, the current knowledge regarding induced resistance by EphA2 in cancer treatment is summarized, and the types of cancer that lead to the most cancer-related deaths are highlighted. Some EphA2 inhibitors were also investigated. Regardless of whether the cancer treatment has reached a drug-resistance stage in EphA2-overexpressing tumors, once EphA2 is involved in cancer progression and aggressiveness, targeting EphA2 is a promising therapeutic strategy, especially in combination with other target-drugs for synergistic effect. For that reason, monoclonal antibodies against EphA2 and inhibitors of this receptor should be investigated for efficacy and drug toxicity.

Signals transduced by Eph receptors and ephrin ligands converge on MAP kinase and AKT pathways in human cancers

Eph receptors, the largest known family of receptor tyrosine kinases, and ephrin ligands have been implicated in a variety of human cancers. The novel bidirectional signaling events initiated by binding of Eph receptors to their cognate ephrin ligands modulate many cellular processes such as proliferation, metastasis, angiogenesis, invasion, and apoptosis. The relationships between the abundance of a unique subset of Eph receptors and ephrin ligands with associated cellular processes indicate a key role of these molecules in tumorigenesis. The combinatorial expression of these molecules converges on MAP kinase and/or AKT/mTOR signaling pathways. The intracellular target proteins of the initial signal may, however, vary in some cancers. Furthermore, we have also described the commonality of up- and down-regulation of individual receptors and ligands in various cancers. The current state of research in Eph receptors illustrates MAP kinase and mTOR pathways as plausible targets for therapeutic interventions in various cancers.

Ligand-independent EphA2 contributes to chemoresistance in small-cell lung cancer by enhancing PRMT1-mediated SOX2 methylation

Chemoresistance is the crux of clinical treatment failure of small-cell lung cancer (SCLC). Cancer stem cells play a critical role in therapeutic resistance of malignant tumors. Studies have shown that the role of erythropoietin-producing hepatocellular A2 (EphA2) in tumors is complex. This study aimed to test the hypothesis that ligand-independent activation of EphA2 modulates chemoresistance by enhancing stemness in SCLC. We verified that EphA2 was activated in chemoresistance sublines in a ligand-independent manner rather than a ligand-dependent manner. Ligand-independent EphA2 enhanced the expression of stemness-associated biomarkers (CD44, Myc, and SOX2), accelerated epithelial-mesenchymal transition (EMT) and reinforced self-renewal to drive the chemoresistance of SCLC, while the P817H mutant EphA2 neutralized intrinsic function. Co-immunoprecipitation (co-IP) and GST-pull down experiments were conducted to verify that EphA2 directly interacted with PRMT1. Moreover, EphA2 increased the expression and activity of PRMT1. Whereafter, PRMT1 interacted with and methylated SOX2 to induce stemness and chemoresistance in SCLC. Pharmacological inhibition of EphA2 showed a synergistic anti-tumor effect with chemotherapy in preclinical models, including patient-derived xenograft (PDX) models. These findings highlight, for the first time, that the EphA2/PRMT1/SOX2 pathway induces chemoresistance in SCLC by promoting stemness. EphA2 is a potential therapeutic target in SCLC treatment.

May EPH/Ephrin Targeting Revolutionize Lung Cancer Treatment?

Lung cancer (LC) is the leading cause of cancer death in the United States. Erythropoietin-producing hepatocellular receptors (EPHs) comprise the largest receptor tyrosine kinases (RTKs) family in mammals. EPHs along with their ligands, EPH-family receptor-interacting proteins (ephrins), have been found to be either up- or downregulated in LC cells, hence exhibiting a defining role in LC carcinogenesis and tumor progression. In their capacity as membrane-bound molecules, EPHs/ephrins may represent feasible targets in the context of precision cancer treatment. In order to investigate available therapeutics targeting the EPH/ephrin system in LC, a literature review was conducted, using the MEDLINE, LIVIVO, and Google Scholar databases. EPHA2 is the most well-studied EPH/ephrin target in LC treatment. The targeting of EPHA2, EPHA3, EPHA5, EPHA7, EPHB4, EPHB6, ephrin-A1, ephrin-A2, ephrin-B2, and ephrin-B3 in LC cells or xenograft models not only directly correlates with a profound LC suppression but also enriches the effects of well-established therapeutic regimens. However, the sole clinical trial incorporating a NSCLC patient could not describe objective anti-cancer effects after anti-EPHA2 antibody administration. Collectively, EPHs/ephrins seem to represent promising treatment targets in LC. However, large clinical trials still need to be performed, with a view to examining the effects of EPH/ephrin targeting in the clinical setting.

EphA2 Promotes the Development of Cervical Cancer through the CXCL11/PD-L1 Pathway

Erythropoietin-producing hepatoma receptor A2 (EphA2), receptor tyrosine kinase, the most widespread member of the largest receptor tyrosine kinase family, plays a critical role in physiological and pathological conditions. In recent years, the role of EphA2 in the occurrence and development of cancer has become a research hotspot and is considered a promising potential target. Our previous studies have shown that EphA2 has an indisputable cancer-promoting role in cervical cancer, but its related mechanism requires further research. In this study, high-throughput sequencing was performed on EphA2 knockdown cervical cancer cells and the control group. An analysis of differentially expressed genes revealed that EphA2 may exert its cancer-promoting effect through C-X-C motif chemokine ligand 11 (CXCL11). In addition, we found that EphA2 could further regulate programmed cell death ligand 1 (PD-L1) through CXCL11. This has also been further demonstrated in in vivo experiments. Our study demonstrated that EphA2 plays a tumor-promoting role in cervical carcinoma through the CXCL11/PD-L1 pathway, providing new guidance for the targeted therapy and combination therapy of cervical carcinoma.

Anlotinib Inhibits Tumor Angiogenesis and Promotes the Anticancer Effect of Radiotherapy on Esophageal Cancer through Inhibiting EphA2

Background

Anlotinib is a novel multitarget tyrosine kinase inhibitor for tumor angiogenesis and has antitumor activity in a variety of solid tumors. Given that, our study was designed to unearth the mechanism of anlotinib in radioresistant esophageal cancer (EC) cells.

Methods

Radioresistant EC cell lines TE-1R and KYSE-150R were established by multiple fractionated irradiation. Detection of cell proliferation was governed by the MTT assay, angiogenesis by the tube formation assay, and cell migration and invasion by the transwell assay. Lastly, RT-qPCR Western blotting was employed to detect the expression of related genes. Cancerous cells showing tumor growth were then detected by tumor xenografts in mice.

Results

Radioresistant EC cell lines TE-1R and KYSE-150R were successfully established. Anlotinib downregulated EphA2 inhibited proliferation, angiogenesis, migration, and invasion of radioresistant EC cells in vitro. The up-regulated expression of EphA2 in both EC cell lines and radioresistant EC cells, along with anlotinib, in turn, inhibited the expression of EphA2 in radioresistant EC cells. Inhibiting EphA2 also enhanced anlotinib-mediated effects on radioresistant EC cells, so as to restrain cell proliferation, angiogenesis, migration, and invasion. Correspondingly, overexpression of EphA2 is capable of reversing the therapeutic effect of anlotinib on radioresistant EC cells. Also, anlotinib enhances the inhibitory effect of irradiation on mice.

Conclusion

It is concluded that anlotinib inhibits EphA2 expression, thereby suppressing angiogenesis and resensitizing EC cells to radiotherapy, providing another perspective to overcome radioresistance in EC.

miR-10b-5p Suppresses the Proliferation and Invasion of Primary Hepatic Carcinoma Cells by Downregulating EphA2

Objective

To analyze the function of miR-10b-5p in suppressing the invasion and proliferation of primary hepatic carcinoma cells by downregulating erythropoietin-producing hepatocellular receptor A2 (EphA2). Material and Methods. Eighty-six hepatic carcinoma (HCC) tissue specimens and 86 corresponding adjacent tissue specimens were collected, and the mRNA expression of miR-10b-5p and Ephrin type-A receptor 2 (EphA2) in the specimens was determined using a reverse transcription-polymerase chain reaction (RT-PCR) assay. Western blot was employed to quantify EphA2, B-cell chronic lymphocytic leukemia/lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and Caspase-3 in the cells, and CCK8, Transwell assay, and flow cytometry were applied to evaluate the proliferation, invasion, and apoptosis of cells, respectively. Moreover, the dual luciferase reporter assay was utilized for correlation analysis between miR-10b-5p and EphA2.

Results

miR-10b-5p was lowly expressed in HCC, while EphA2 was highly expressed. Cell experiments revealed that miR-10b-5p overexpression or EphA2 knockdown could reduce cell proliferation, accelerate apoptosis, strongly upregulate Bax and Caspase-3, and downregulate Bcl-2. In contrast, miR-10b-5p knockdown or EphA2 overexpression gave rise to reverse biological phenotypes. Furthermore, dual luciferase reporter assay verified that miR-10b-5p was a target of EphA2, and the rescue experiment implied that transfection of pCMV-EphA2 or Si-EphA2 could reverse EphA2 expression and cell biological functions caused by miR-10b-5p overexpression or knockdown.

Conclusions

miR-10b-5p reduced HCC cell proliferation but accelerate apoptosis by regulating EphA2, suggesting it has the potential to be a clinical target for HCC.

Antitumor activity of the third generation EphA2 CAR-T cells against glioblastoma is associated with interferon gamma induced PD-L1

Glioblastoma (GBM) is the most common and aggressive brain malignancy in adults and is currently incurable with conventional therapies. The use of chimeric antigen receptor (CAR) modified T cells has been successful in clinical treatment of blood cancers, except solid tumors such as GBM. This study generated two third-generation CARs targeting different epitopes of ephrin type-A receptor 2 (EphA2) and examined their anti-GBM efficacy in vitro and in tumor-bearing mice. We observed that these two types of T cells expressing CAR (CAR-T) targeting EphA2 could be activated and expanded by EphA2 positive tumor cells in vitro. The survival of tumor-bearing mice after EphA2 CAR-T cell treatment was significantly improved. T cells transduced with one of the two EphA2 CARs exhibited better anti-tumor activity, which is related to the upregulation of CXCR-1/2 and appropriate interferon-γ (IFN-γ) production. CAR-T cells expressed excessively high level of IFN-γ exhibited poor anti-tumor activity resulting from inducing the upregulation of PD-L1 in GBM cells. The combination of CAR-T cells with poor anti-tumor activity and PD1 blockade improved the efficacy in tumor-bearing mice. In conclusion, both types of EphA2 CAR-T cells eliminated 20%-50% of GBM in xenograft mouse models. The appropriate combination of IFN-γ and CXCR-1/2 levels is a key factor for evaluating the antitumor efficiency of CAR-T cells.

A Putative Single-Photon Emission CT Imaging Tracer for Erythropoietin-Producing Hepatocellular A2 Receptor

Erythropoietin-producing hepatocellular (Eph) receptors are receptor tyrosine kinases involved in cell-cell contact. The EphA2 receptor is associated with cancer proliferation and migration. Therefore, EphA2 receptor imaging has the potential for cancer diagnosis. Here, we synthesized N-(5-((4-((4-ethylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)carbamoyl)-2-methylphenyl)-5-[¹²³I]iodonicotinamide ([¹²³I]ETB) and evaluated it as an imaging tracer for single-photon emission computed tomography (SPECT) imaging of the EphA2 receptor. [¹²³I]ETB was designed on the basis of ALW-II-41-27, an inhibitor of EphA2 receptor kinase. Nonradioactive ETB was also synthesized and has been shown to efficiently inhibit EphA2 receptor kinase activity in vitro (IC₅₀: ETB, 90.2 ± 18.9 nM). A cell-binding assay demonstrated that [¹²⁵I]ETB binds specifically to the EphA2 receptor. The ex vivo biodistribution study of [¹²⁵I]ETB in U87MG tumor-bearing mice also revealed tumor uptake (2.2% ID/g at 240 min). In addition, [¹²³I]ETB uptake in tumors was visualized via SPECT/CT imaging. On the basis of the above, [¹²³I]ETB can be considered a potential SPECT imaging tracer for the EphA2 receptor.

Y772 phosphorylation of EphA2 is responsible for EphA2-dependent NPC nasopharyngeal carcinoma growth by Shp2/Erk-1/2 signaling pathway

EphA2 is an important oncogenic protein and emerging drug target, but the oncogenic role and mechanism of ligand-independent phosphorylation of EphA2 at tyrosine 772 (pY772-EphA2) is unclear. In this study, we established nasopharyngeal carcinoma (NPC) cell lines with stable expression of exogenous EphA2 and EphA2-Y772A (phosphorylation inactivation) using endogenous EphA2-knockdown cells, and observed that pY772A EphA2 was responsible for EphA2-promoting NPC cell proliferation and anchorage-independent and in vivo growth in mice. Mechanistically, EphA2-Y772A mediated EphA2-activating Shp2/Erk-1/2 signaling pathway in the NPC cells, and Gab1 (Grb2-associated binder 1) and Grb2 (growth factor receptor-bound protein 2) were involved in pY772-EphA2 activating this signaling pathway. Our results further showed that Shp2/Erk-1/2 signaling mediated pY772-EphA2-promoting NPC cell proliferation and anchorage-independent growth. Moreover, we observed that EphA2 tyrosine kinase inhibitor ALW-II-41-27 inhibited pY772-EphA2 and EphA2-Y772A decreased the inhibitory effect of ALW-II-41-27 on NPC cell proliferation. Collectively, our results demonstrate that pY772-EphA2 is responsible for EphA2-dependent NPC cell growth in vitro and in vivo by activating Shp2/Erk-1/2 signaling pathway, and is a pharmacologic target of ALW-II-41-27, suggesting that pY772-EphA2 can serve as a therapeutic target in NPC and perhaps in other cancers.

The miR-1224-5p/TNS4/EGFR axis inhibits tumour progression in oesophageal squamous cell carcinoma

Oesophageal squamous cell carcinoma (ESCC) is a common and aggressive malignancy. Although many molecular alterations have been observed in ESCC, the mechanisms underlying the development and progression of this disease remain unclear. In the present study, miR-1224-5p was identified to be downregulated in ESCC tissues compared to normal tissues, and its low expression was correlated with shorter survival time in patients. In vitro experiments showed that miR-1224-5p inhibited the proliferation, colony formation, migration and invasion of ESCC cells. Mechanistic investigation revealed that miR-1224-5p directly targeted TNS4 and inhibited its expression, which led to the inactivation of EGFR-EFNA1/EPHA2-VEGFA (vascular endothelial growth factor A) signalling. Experiments in vivo confirmed the suppressive effect of miR-1224-5p on oesophageal cancer cells. By immunohistochemistry analysis of ESCC specimens, we found that TNS4 expression was positively correlated with that of VEGFA, and was significantly associated with lymph node metastasis and shorter survival time in patients. Together, our data suggest that miR-1224-5p downregulation is a frequent alteration in ESCC that promotes cell proliferation, migration, invasion and tumour growth by activating the EGFR-EFNA1/EPHA2-VEGFA signalling pathway via inhibition of TNS4 expression. Decreased miR-1224-5p and elevated TNS4 are unfavourable prognostic factors for ESCC patients.

Metabolic Reprogramming in Metastatic Melanoma with Acquired Resistance to Targeted Therapies: Integrative Metabolomic and Proteomic Analysis

Treatments of metastatic melanoma underwent an impressive development over the past few years, with the emergence of small molecule inhibitors targeting mutated proteins, such as BRAF, NRAS, or cKIT. However, since a significant proportion of patients acquire resistance to these therapies, new strategies are currently being considered to overcome this issue. For this purpose, melanoma cell lines with mutant BRAF, NRAS, or cKIT and with acquired resistances to BRAF, MEK, or cKIT inhibitors, respectively, were investigated using both ¹H-NMR-based metabonomic and protein microarrays. The ¹H-NMR profiles highlighted a similar go and return pattern in the metabolism of the BRAF, NRAS, and cKIT mutated cell lines. Indeed, melanoma cells exposed to mutation-specific inhibitors underwent metabolic disruptions following acute exposure but partially recovered their basal metabolism in long-term exposure, most likely acquiring resistance skills. The protein microarrays inquired about the potential cellular mechanisms used by the resistant cells to escape drug treatment, by showing decreased levels of proteins linked to the drug efficacy, especially in the downstream part of the MAPK signaling pathway. Integrating metabonomic and proteomic findings revealed some metabolic pathways (i.e., glutaminolysis, choline metabolism, glutathione production, glycolysis, oxidative phosphorylation) and key proteins (i.e., EPHA2, DUSP4, and HIF-1A) as potential targets to discard drug resistance.