Inhibition of HDACs-EphA2 Signaling Axis with WW437 Demonstrates Promising Preclinical Antitumor Activity in Breast Cancer

68Ga labeled EphA2-targeted cyclic peptide: a novel positron imaging tracer for triple-negative breast cancer?

The absence of better biomarkers currently limits early diagnosis and treatment of triple-negative breast cancer (TNBC). Our previously published study reported that the cyclic-peptide SD01 exhibited specific binding to EphA2 (Ephrin type-A receptor 2) on TNBC. To develop a novel PET imaging agent, we prepared gallium-68 (68Ga) labeled-DOTA-SD01 and evaluated its specificity and effectiveness through micro PET/CT imaging in a TNBC-bearing mouse model. SD01 and a control linear peptide YSA were conjugated to DOTA and subsequently labeled with 68Ga, obtaining 68Ga-DOTA-SD01 and 68Ga-DOTA-YSA. Both showed high radiochemical purity, stability, good hydrophilicity, and high binding affinity to 4T1 cells. Micro PET/CT imaging showed high radioactivity accumulation in tumors; SUVmean (mean standardized uptake value) of tumors in the group of 68Ga-DOTA-SD01 was 3.34 ± 0.25 and 2.65 ± 0.32 in the group of 68Ga-DOTA-YSA; T/NT ratios (target to non-target, SUVmean ratios of tumor to muscle) were 3.12 ± 0.06 and 2.77 ± 0.11 at 30 min, respectively (p < 0.05). The biodistribution study showed that tumor uptake % ID per g (percentage of injected dose per gram of tissue) in the group of 68Ga-DOTA-SD01 was 2.73 ± 0.34, and 1.77 ± 0.38 in the group of 68Ga-DOTA-YSA; T/NT ratios (radioactivity of tumor to muscle) were 3.55 ± 0.12 and 3.05 ± 0.10 for both groups at 30 min, respectively (p < 0.05). All these suggest that 68Ga-DOTA-SD01 may act as a better novel PET imaging agent for EphA2 positive tumors, such as TNBC.

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.

Targeting Interleukin-13 Receptor α2 and EphA2 in Aggressive Breast Cancer Subtypes with Special References to Chimeric Antigen Receptor T-Cell Therapy

Breast cancer (BCA) remains the leading cause of cancer-related mortality among women worldwide. This review delves into the therapeutic challenges of BCA, emphasizing the roles of interleukin-13 receptor α2 (IL-13Rα2) and erythropoietin-producing hepatocellular receptor A2 (EphA2) in tumor progression and resistance. Highlighting their overexpression in BCA, particularly in aggressive subtypes, such as Her-2-enriched and triple-negative breast cancer (TNBC), we discuss the potential of these receptors as targets for chimeric antigen receptor T-cell (CAR-T) therapies. We examine the structural and functional roles of IL-13Rα2 and EphA2, their pathological significance in BCA, and the promising therapeutic avenues their targeting presents. With an in-depth analysis of current immunotherapeutic strategies, including the limitations of existing treatments and the potential of dual antigen-targeting CAR T-cell therapies, this review aims to summarize potential future novel, more effective therapeutic interventions for BCA. Through a thorough examination of preclinical and clinical studies, it underlines the urgent need for targeted therapies in combating the high mortality rates associated with Her-2-enriched and TNBC subtypes and discusses the potential role of IL-13Rα2 and EphA2 as promising candidates for the development of CAR T-cell therapies.

Co-Delivery of siRNA and Docetaxel to Cancer Cells by NLC for Therapy

The present study aims to develop a delivery system that can carry small interference RNA (siRNA) with small-molecule chemotherapeutic drugs, which can be used in cancer treatment. The drug delivery system combines the advantages of a therapeutic agent with two different mechanisms to ensure that it is used efficiently for cancer therapy. In this study, a nanostructured lipid carrier system was prepared, Docetaxel was loaded to these systems, and the Eph siRNA was adsorbed to the outer surface. In addition, DOTAP was added to the lipophilic phase to load a positive charge on the lipidic structure for interaction with the cells. Moreover, characterization, cytotoxicity, and transfection procedures were performed on the whole system. This candidate system was also compared to Taxotere, which is the first approved Docetaxel-containing drug on the market. Given the results, it was determined that the particle size of NLC-DTX was 165.3 ± 3.5 nm, the ζ potential value was 38.2 ± 1.7 mV, and the PDI was 0.187 ± 0.024. Entrapment efficacy of nanoparticles was found to be 92.89 ± 0.21%. It was determined that the lipidic system prepared in vitro release analyses were able to provide sustained release and exhibit cytotoxicity, even at doses lower than the dose used for Taxotere. The formulations prepared had a higher level of effect on cells when compared with pure DTX and Taxotere, but they also exhibited time-dependent cytotoxicity. It was also observed that the use of Eph siRNA together with the chemotherapeutic agent via formulation also contributed to this cell death. The results of the present study indicate that there is a promising carrier system in order to deliver hydrophilic nucleic acids, such as siRNA, together with lipophilic drugs in cancer treatment.

Eph receptors and ephrins in cancer progression

Evidence implicating Eph receptor tyrosine kinases and their ephrin ligands (that together make up the 'Eph system') in cancer development and progression has been accumulating since the discovery of the first Eph receptor approximately 35 years ago. Advances in the past decade and a half have considerably increased the understanding of Eph receptor-ephrin signalling mechanisms in cancer and have uncovered intriguing new roles in cancer progression and drug resistance. This Review focuses mainly on these more recent developments. I provide an update on the different mechanisms of Eph receptor-ephrin-mediated cell-cell communication and cell autonomous signalling, as well as on the interplay of the Eph system with other signalling systems. I further discuss recent advances in elucidating how the Eph system controls tumour expansion, invasiveness and metastasis, supports cancer stem cells, and drives therapy resistance. In addition to functioning within cancer cells, the Eph system also mediates the reciprocal communication between cancer cells and cells of the tumour microenvironment. The involvement of the Eph system in tumour angiogenesis is well established, but recent findings also demonstrate roles in immune cells, cancer-associated fibroblasts and the extracellular matrix. Lastly, I discuss strategies under evaluation for therapeutic targeting of Eph receptors-ephrins in cancer and conclude with an outlook on promising future research directions.

Inonotsutriol E from Inonotus obliquus exhibits promising anti breast cancer activity via regulating the JAK2/STAT3 signaling pathway

The aim of the present study was to investigate the small molecule anticancer agents in the medicinal fungus Inonotus obliquus and further characterize their possible molecular mechanisms. Chemical fractionation of the ethanol extract of this fungus yielded a panel of lanostane triterpenoids (1-13) and their structures were characterized on the basis of spectroscopic methods. Subsequent preliminary biological screening on these triterpenoids revealed significant cytotoxicity against various tumor cell lines, and inonotsutriol E (ITE, 1) showed the best activity. Of note, ITE displayed stronger inhibitory effect on breast cancer (BC) than other tumor cell lines. Functional assays revealed that ITE significantly inhibited the growth and migration of BC cells and exerted promising antitumor activity in patient-derived organoids (PDO). Further mechanistic study demonstrated that the anti-BC activity of ITE was achieved via inhibiting JAK2/STAT3 signal axis. Taken together, the current work has demonstrated the therapeutic material basis of I. obliquus and provided further evidence for the traditional application of this medicinal species in cancer prevention and treatment.

Study on the Relationship Between Differentially Expressed Proteins in Breast Cancer and Lymph Node Metastasis

INTRODUCTION

Lymph node metastasis is a cause of poor prognosis in breast cancer. Mass spectrometry-based proteomics aims to map the protein landscapes of biological samples and profile tumors more comprehensively. Here, proteomics was employed to identify differentially expressed proteins (DEPs) that were associated with lymph node metastasis.

METHODS

Tandem mass tag (TMT) quantitative proteomic approaches were applied for extensive profiling of conditioned medium of MDA-MB-231 and MCF7 cell lines and serums of patients who did or did not have lymph node metastasis, and DEPs were analyzed by bioinformatics. Furthermore, potential secreted or membrane proteins MUC5AC, ITGB4, CTGF, EphA2, S100A4, PRDX2, and PRDX6 were selected for verification in 114 tissue microarray samples of breast cancer using the immunohistochemical method. The relevant data was analyzed and processed by independent sample t test, chi-square test, or Fisher's exact test using SPSS 22.0 software.

RESULTS

In the conditioned medium of MDA-MB-231 cell lines, 154 proteins were upregulated, while 136 were downregulated compared to those of MCF7. In the serum of patients with breast cancer and lymph node metastasis, 17 proteins were upregulated, and 5 proteins were downregulated compared to those without lymph node metastasis. Furthermore, according to tissue verification, CTGF, EphA2, S100A4, and PRDX2 were associated with breast cancer lymph node metastasis.

CONCLUSION

Our study provides a new perspective for the understanding of the role of DEPs (especially CTGF, EphA2, S100A4, and PRDX2) in the development and metastasis of breast cancer. They could become potential diagnostic and prognostic biomarkers and therapeutic targets.

Lipofectamine 2000™ at transfection dose promotes EphA2 transcription in an HDAC4-dependent manner to reduce its cytotoxicity

The cationic liposome is well-known as an efficient nucleic acid delivery tool; however, the stress responses induced by liposome per se have been rarely revealed. In this study, we found that Lipofectamine™ 2000 (lipo2000), a commonly used commercial cationic liposome transfection, could upregulate EphA2 mRNA expression in multiple cells at transfection dose. Furthermore, lipo2000 treatment could increase the level of EphA2 hnRNA (heterogeneous nuclear RNA). Lipo2000-induced EphA2 upregulation could be depleted upon global transcription inhibition, proving that lipo2000 upregulates EphA2 expression via activating its transcription. Moreover, HDAC4 depletion, a known EphA2 trans-acting regulatory factor, could eliminate the lipo2000-induced EphA2 upregulation, demonstrating that lipo2000 promotes EphA2 transcription in an HDAC4 dependent manner. Functionally, EphA2 knockdown did not affect GFP expression level and the interfering efficacy of siGAPDH, suggesting that EphA2 is unrelated to the nucleic acid delivery capacity of lipo2000. Nevertheless, EphA2 depletion significantly activated autophagy and apoptosis, increasing the cytotoxic effects of lipo2000, which could be rescued by EphA2 restoration, indicating that EphA2 is essential to overcome liposome-related cytotoxicity. Finally, we found that lipo2000 could activate EphA2 transcription in an HDAC4-dependent manner. EphA2 is not associated with the transfection efficiency of lipo2000, but it is vital to reduce lipo2000 cytotoxicity, suggesting that when conducting liposome-mediated gene function studies, especially for EphA2, the stress response of liposomes should be considered to obtain objective results.

An Activity-Based Photosensitizer to Reverse Hypoxia and Oxidative Resistance for Tumor Photodynamic Eradication

Photodynamic therapy (PDT) has been a well-accepted clinical treatment for malignant tumors owing to its noninvasiveness and high spatiotemporal selectivity. However, the treatment outcome of current PDT applications is hindered by hypoxia and intracellular oxidative resistance of solid tumors. Recent studies have shown that inhibiting histone deacetylases (HDACs) can induce cell ferroptosis, reverse hypoxia, and elevate oxidative status. Theoretically, the design and synthesis of activity-based photosensitizers that target HDACs can address the bottlenecks of PDT. Herein, the concept of an activity-based photosensitizer is presented for targeting HDACs, which is designed based on a quinoxalinone scaffold through a pharmacophore migration strategy. The developed activity-based photosensitizer can inhibit HDACs, and overcome hypoxia and intracellular oxidative resistance, realizing the full potential of photosensitizers for malignant tumor treatment. The molecular design strategy proposed in this project should provide theoretical guidance for the development of ideal photosensitizers for practical applications.

Hunting for Novel Routes in Anticancer Drug Discovery: Peptides against Sam-Sam Interactions

Among the diverse protein binding modules, Sam (Sterile alpha motif) domains attract attention due to their versatility. They are present in different organisms and play many functions in physiological and pathological processes by binding multiple partners. The EphA2 receptor contains a Sam domain at the C-terminus (EphA2-Sam) that is able to engage protein regulators of receptor stability (including the lipid phosphatase Ship2 and the adaptor Odin). Ship2 and Odin are recruited by EphA2-Sam through heterotypic Sam-Sam interactions. Ship2 decreases EphA2 endocytosis and consequent degradation, producing chiefly pro-oncogenic outcomes in a cellular milieu. Odin, through its Sam domains, contributes to receptor stability by possibly interfering with ubiquitination. As EphA2 is upregulated in many types of tumors, peptide inhibitors of Sam-Sam interactions by hindering receptor stability could function as anticancer therapeutics. This review describes EphA2-Sam and its interactome from a structural and functional perspective. The diverse design strategies that have thus far been employed to obtain peptides targeting EphA2-mediated Sam-Sam interactions are summarized as well. The generated peptides represent good initial lead compounds, but surely many efforts need to be devoted in the close future to improve interaction affinities towards Sam domains and consequently validate their anticancer properties.

Targeting key proteins involved in transcriptional regulation for cancer therapy: Current strategies and future prospective

The key proteins involved in transcriptional regulation play convergent roles in cellular homeostasis, and their dysfunction mediates aberrant gene expressions that underline the hallmarks of tumorigenesis. As tumor progression is dependent on such abnormal regulation of transcription, it is important to discover novel chemical entities as antitumor drugs that target key tumor-associated proteins involved in transcriptional regulation. Despite most key proteins (especially transcription factors) involved in transcriptional regulation are historically recognized as undruggable targets, multiple targeting approaches at diverse levels of transcriptional regulation, such as epigenetic intervention, inhibition of DNA-binding of transcriptional factors, and inhibition of the protein-protein interactions (PPIs), have been established in preclinically or clinically studies. In addition, several new approaches have recently been described, such as targeting proteasomal degradation and eliciting synthetic lethality. This review will emphasize on accentuating these developing therapeutic approaches and provide a thorough conspectus of the drug development to target key proteins involved in transcriptional regulation and their impact on future oncotherapy.

The expression and diagnostic value of serum levels of EphA2 and VEGF-A in patients with colorectal cancer

BACKGROUND

Several molecules are highly expressed in the serum of cancer patients, and can be used as serological markers. This approach has become one of the important auxiliary diagnostic methods for cancer.

AIM

To investigate the correlation between the serum levels of EphA2 and VEGF-A and the pathogenesis of colorectal cancer (CRC) as well as the potential value of these molecules in the diagnosis of CRC.

METHODS

ELISA was used to detect the levels of EphA2 and VEGF-A in the peripheral venous serum of 106 newly diagnosed patients with CRC and 69 normal controls. The relationship between the serum EphA2 and VEGF-A levels and the clinicopathological characteristics of CRC patients was analyzed. ROC analysis was used to investigate the diagnostic value of the serum EphA2 and VEGF-A levels in CRC, and the optimal cutoff value was calculated.

RESULTS

The serum levels of EphA2 and VEGF-A in the CRC group were higher than those in the control as well as CEA, the serum level of EphA2 was positively correlated with the VEGF-A levels, but neither was significantly associated with the clinicopathological parameters of CRC. The ROC curve showed that the single index AUC was < 0.7 except for VEGF-A, and the accuracy of the combined diagnosis was higher than that of any other single index. The diagnosis scheme involving all three markers was the best (the sensitivity was 60.40%, the specificity was 92.8%, and the accuracy was 53.1%). The best critical values calculated were EphA2 > 297.92 ng/ml, EphA2 > 183.92 pg/ml and CEA > 5.19 ng/ml.

CONCLUSION

The serum levels of EphA2 and VEGF-A are high in CRC patients, and the combine detection of CEA, EphA2 and VEGF-A can significantly improve the diagnostic accuracy of CRC.

EphA2 Is a Clinically Relevant Target for Breast Cancer Bone Metastatic Disease

EphA2 receptor tyrosine kinase (RTK) is highly expressed in breast tumor cells across multiple molecular subtypes and correlates with poor patient prognosis. In this study, the potential role of EphA2 in this clinically relevant phenomenon is investigated as metastasis of breast cancer to bone is a major cause of morbidity and mortality in patients. It was found that the EphA2 function in breast cancer cells promotes osteoclast activation and the development of osteolytic bone disease. Blocking EphA2 function molecularly and pharmacologically in breast tumors reduced the number and size of bone lesions and the degree of osteolytic disease in intratibial and intracardiac mouse models, which correlated with a significant decrease in the number of osteoclasts at the tumor-bone interface. EphA2 loss of function in tumor cells impaired osteoclast progenitor differentiation in coculture, which is mediated, at least in part, by reduced expression of IL-6. EPHA2 transcript levels are enriched in human breast cancer bone metastatic lesions relative to visceral metastatic sites; EphA2 protein expression was detected in breast tumor cells in bone metastases in patient samples, supporting the clinical relevance of the study's findings. These data provide a strong rationale for the development and application of molecularly targeted therapies against EphA2 for the treatment of breast cancer bone metastatic disease. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

EphA2: A promising therapeutic target in breast cancer

Ephrin type-A receptor 2 (EphA2), a receptor tyrosine kinase, is overexpressed in human breast cancers often linked to poor patient prognosis. Accumulating evidence demonstrates that EphA2 plays important roles in several critical processes associated with malignant breast progression, such as proliferation, survival, migration, invasion, drug resistance, metastasis, and angiogenesis. As its inhibition through multiple approaches can inhibit the growth of breast cancer and restore drug sensitivity, EphA2 has become a promising therapeutic target for breast cancer treatment. Here, we summarize the expression, functions, mechanisms of action, and regulation of EphA2 in breast cancer. We also list the potential therapeutic strategies targeting EphA2. Furthermore, we discuss the future directions of studying EphA2 in breast cancer.

The Expression of the Cancer-Associated lncRNA Snhg15 Is Modulated by EphrinA5-Induced Signaling

The Eph receptor tyrosine kinases and their respective ephrin-ligands are an important family of membrane receptors, being involved in developmental processes such as proliferation, migration, and in the formation of brain cancer such as glioma. Intracellular signaling pathways, which are activated by Eph receptor signaling, are well characterized. In contrast, it is unknown so far whether ephrins modulate the expression of lncRNAs, which would enable the transduction of environmental stimuli into our genome through a great gene regulatory spectrum. Applying a combination of functional in vitro assays, RNA sequencing, and qPCR analysis, we found that the proliferation and migration promoting stimulation of mouse cerebellar granule cells (CB) with ephrinA5 diminishes the expression of the cancer-related lncRNA Snhg15. In a human medulloblastoma cell line (DAOY) ephrinA5 stimulation similarly reduced SNHG15 expression. Computational analysis identified triple-helix-mediated DNA-binding sites of Snhg15 in promoters of genes found up-regulated upon ephrinA5 stimulation and known to be involved in tumorigenic processes. Our findings propose a crucial role of Snhg15 downstream of ephrinA5-induced signaling in regulating gene transcription in the nucleus. These findings could be potentially relevant for the regulation of tumorigenic processes in the context of glioma.

Targeting EphA2 in cancer

Eph receptors and the corresponding Eph receptor-interacting (ephrin) ligands jointly constitute a critical cell signaling network that has multiple functions. The tyrosine kinase EphA2, which belongs to the family of Eph receptors, is highly produced in tumor tissues, while found at relatively low levels in most normal adult tissues, indicating its potential application in cancer treatment. After 30 years of investigation, a large amount of data regarding EphA2 functions have been compiled. Meanwhile, several compounds targeting EphA2 have been evaluated and tested in clinical studies, albeit with limited clinical success. The present review briefly describes the contribution of EphA2-ephrin A1 signaling axis to carcinogenesis. In addition, the roles of EphA2 in resistance to molecular-targeted agents were examined. In particular, we focused on EphA2's potential as a target for cancer treatment to provide insights into the application of EphA2 targeting in anticancer strategies. Overall, EphA2 represents a potential target for treating malignant tumors.

The application of histone deacetylases inhibitors in glioblastoma

The epigenetic abnormality is generally accepted as the key to cancer initiation. Epigenetics that ensure the somatic inheritance of differentiated state is defined as a crucial factor influencing malignant phenotype without altering genotype. Histone modification is one such alteration playing an essential role in tumor formation, progression, and resistance to treatment. Notably, changes in histone acetylation have been strongly linked to gene expression, cell cycle, and carcinogenesis. The balance of two types of enzyme, histone acetyltransferases (HATs) and histone deacetylases (HDACs), determines the stage of histone acetylation and then the architecture of chromatin. Changes in chromatin structure result in transcriptional dysregulation of genes that are involved in cell-cycle progression, differentiation, apoptosis, and so on. Recently, HDAC inhibitors (HDACis) are identified as novel agents to keep this balance, leading to numerous researches on it for more effective strategies against cancers, including glioblastoma (GBM). This review elaborated influences on gene expression and tumorigenesis by acetylation and the antitumor mechanism of HDACis. Besdes, we outlined the preclinical and clinical advancement of HDACis in GBM as monotherapies and combination therapies.

HDAC7 promotes the oncogenicity of nasopharyngeal carcinoma cells by miR-4465-EphA2 signaling axis

HDAC7 plays a crucial role in cancers, and is the main drug target of several HDAC inhibitors. However, the role and mechanism of HDAC7 in nasopharyngeal carcinoma (NPC) are still unclear. In this study, we observed that HDAC7 was significantly upregulated in the NPC tissues relative to normal nasopharyngeal mucosa (NNM) tissues, HDAC7 expression levels were positively correlated with NPC progression and negatively correlated with patient prognosis, and HDAC7 knockdown dramatically inhibited the in vitro proliferation, migration, and invasion of NPC cells, and the growth of NPC xenografts in mice, indicating the HDAC7 promotes the oncogenicity of NPC. Mechanistically, HDAC7 promoted the in vitro proliferation, migration, and invasion of NPC cells by upregulating EphA2, in which miR-4465 mediated HDAC7-regulating EphA2, a direct target gene of miR-4465. We further showed that miR-4465 was significantly downregulated in the NPC tissues relative to NNM tissues, and inhibited the in vitro proliferation, migration, and invasion of NPC cells by targeting EphA2 expression. Moreover, we observed that the expressions of HDAC7, miR-4465, and EphA2 in NPC tissues were correlated. The results suggest that HDAC7 promotes the oncogenicity of NPC by downregulating miR-4465 and subsequently upregulating EphA2, highlighting HDAC7 as a potential therapeutic target for NPC.

Pracinostat (SB939), a histone deacetylase inhibitor, suppresses breast cancer metastasis and growth by inactivating the IL-6/STAT3 signalling pathways

AIMS

Histone deacetylases inhibitors have shown favorable antitumor activity in clinical investigations. In the present study, we assessed the effects of a novel hydroxamic acid-based HDAC inhibitor, SB939, on breast cancer metastasis and tumor growth and characterized the underlying molecular mechanisms.

MAIN METHODS

MTS, Wound-healing, and Transwell chamber invasion assays were used to detect the inhibition effects of SB939 on proliferation, migration, and invasion of breast cancer cells. Western blot, cellular immunofluorescence, and EMSA were used to explore the molecular mechanism of SB939 in suppressing breast cancer metastasis. MDA-MB-231 subcutaneous tumor-bearing model of nude mice and the spontaneous metastasis model of breast cancer were both applied to verify in vivo anti-tumor growth and anti-metastatic effects.

KEY FINDINGS

Our results demonstrated that SB939 at 0.5-1 μmol/L markedly impaired the chemotactic motility of breast cancer cells. SB939 reversed epithelial-mesenchymal transition (EMT) process, as evidenced by upregulation E-cadherin expression and downregulation expressions of N-cadherin and vimentin through increasing the levels of ac-histone H3 and H4 and drecreasing the expressiongs of HDAC 5 and 4. This cascade inhibition mediated by SB939 was well interpreted by inactivating phosphorylation of STAT3, blocking its DNA-binding activity, and decreasing the expressions of STAT3-dependent target genes, including MMP2 and MMP9. Furhtermore, we found that SB939 significantly inhibited breast cancer metastasis and tumor growth in vivo and showed superior anti-tumor properties compared with SAHA in two breast cancer animal models.

SIGNIFICANCE

Our findings indicate that SB939 may be an effective therapeutic option for treating advanced breast cancer.

Histone Deacetylases and their Inhibitors in Cancer Epigenetics

Histone deacetylases (HDAC) and histone deacetylase inhibitors (HDACi) have greatly impacted the war on cancer. Their role in epigenetics has significantly altered the development of anticancer drugs used to treat the most rare, persistent forms of cancer. During transcription, HDAC and HDACi are used to regulate the genetic mutations found in cancerous cells by removing and/or preventing the removal of the acetyl group on specific histones. This activity determines the relaxed or condensed conformation of the nucleosome, changing the accessibility zones for transcription factors. These modifications lead to other biological processes for the cell, including cell cycle progression, proliferation, and differentiation. Each HDAC and HDACi class or group has a distinctive mechanism of action that can be utilized to halt the progression of cancerous cell growth. While the use of HDAC- and HDACi-derived compounds are relatively new in treatment of cancers, they have a proven efficacy when the appropriately utilized. This following manuscript highlights the mechanisms of action utilized by HDAC and HDACi in various cancer, their role in epigenetics, current drug manufacturers, and the impact predicative modeling systems have on cancer therapeutic drug discovery.

Epigenetic regulation of IncRNA KCNKI5-ASI in gastric cancer

Background

Long noncoding RNAs (lncRNAs) play an important role in gastric cancer. In this study, we aimed to uncover the epigenetic regulatory mechanism of lncRNA KCNK15-AS1 in gastric cancer progression.

Patients and methods

Forty patients were included in the study. The expression of KCNK15-AS1 was detected by real-time PCR (RT-PCR), the promoter of KCNK15-AS1 was detected by methylation-specific PCR, and the luciferase assay was performed to detect the relationship between KCNK15-AS1 and miR-21. The relationship of the proteins was explored by an RNA pull-down assay and RNA immunoprecipitation. Chromatin immunoprecipitation was performed to detect the relationship between the promoter and the protein.

Results

The expression of KCNK15-AS1 was lower in the tumor tissue compared to the normal tissue. KCNK15-AS1 interacted with miR-21. Both the overexpression of KCNK15-AS1 and the knockdown of the expression of miR-21 inhibited proliferation and promoted apoptosis and decreased the level of MMP-9, bcl-2, and MMP-2 but increased the level of Bax. In addition, the methylation of KCNK15-AS1 was detected in the tumor tissue but was not detected in the normal tissue. Treatment with 5-azacytidine and chidamide decreased the level of DNMT1 and HDAC1 and increased the level of KCNK15-AS1. The RNA pull-down and RNA immunoprecipitation results showed that KCNK15-AS1 interacted with DNMT1 and HDAC1. The ChIP-seq result showed that the promoter of MAPK interacted with DNMT1, and the promoter of AKT and STAT5 interacted with HDAC1.

Conclusion

In this study, we identified two regulatory axes, namely KCNK15-AS1-DNMT1-MAPK and KCNK15-AS1-HDAC1-AKT, which were associated with gastric cancer progression. Chidamide and 5-azacytidine might provide new modes for treating gastric cancer.

Viewing the Eph receptors with a focus on breast cancer heterogeneity

Aberrant expression of different family members of the Eph/ephrin system, which comprises the Eph receptors (Ephs) and their ligands (ephrins), has been implicated in various malignancies including breast cancer. The latter presents as a heterogeneous disease with diverse molecular, morphologic and clinical behavior signatures. This review reflects the existing Eph/ephrin literature while focusing on breast cancer heterogeneity. Hormone positive, HER2 positive and triple negative breast cancer (TNBC) cell lines, xenografts/mutant animal models and patient samples are examined separately as, in humans, they represent entities with differences in prognosis and treatment. EphA2, EphB4 and EphB6 are the members most extensively studied in breast cancer. Existing research points to the potential use of various Eph/ephrin members as biomarkers for assessing prognosis and selecting the most suitable therapeutic strategies in variable clinical scenarios, also for overcoming drug resistance, in the era of breast cancer heterogeneity.