Expression of HDAC1 and CBP/p300 in human colorectal carcinomas

Discovery of a Highly Potent PROTAC Degrader of p300/CBP Proteins for the Treatment of Enzalutamide-Resistant Prostate Cancer

Prostate cancer therapies against androgen receptor (AR) eventually develop lethal resistance; thus, exploring new therapeutic approaches is urgent for prostate cancer treatment. Acetyltransferase p300/CBP are key coactivators for AR-mediated transcription and represent promising therapeutic targets to inhibit AR activity in prostate cancer. We describe the design synthesis and evaluation of a new class of p300/CBP PROTAC degraders. We identified an excellent p300/CBP degrader MJP6412, which effectively induced degradation of p300/CBP proteins, downregulated AR target genes, and inhibited cell growth of human prostate cancer cell lines and enzalutamide-resistant cells with IC50 even at nanomolar concentrations. Furthermore, MJP6412 demonstrated significant inhibition of tumor growth in a VCaP xenograft model. Collectively, MJP6412 is a promising lead compound for the treatment of prostate cancer, especially enzalutamide-resistant prostate cancer.

Dysregulation of lysine acetylation in the pathogenesis of digestive tract cancers and its clinical applications

Recent advances in high-resolution mass spectrometry-based proteomics have improved our understanding of lysine acetylation in proteins, including histones and non-histone proteins. Lysine acetylation, a reversible post-translational modification, is catalyzed by lysine acetyltransferases (KATs) and lysine deacetylases (KDACs). Proteins comprising evolutionarily conserved bromodomains (BRDs) recognize these acetylated lysine residues and consequently activate transcription. Lysine acetylation regulates almost all cellular processes, including transcription, cell cycle progression, and metabolic functions. Studies have reported the aberrant expression, translocation, and mutation of genes encoding lysine acetylation regulators in various cancers, including digestive tract cancers. These dysregulated lysine acetylation regulators contribute to the pathogenesis of digestive system cancers by modulating the expression and activity of cancer-related genes or pathways. Several inhibitors targeting KATs, KDACs, and BRDs are currently in preclinical trials and have demonstrated anti-cancer effects. Digestive tract cancers, including encompass esophageal, gastric, colorectal, liver, and pancreatic cancers, represent a group of heterogeneous malignancies. However, these cancers are typically diagnosed at an advanced stage owing to the lack of early symptoms and are consequently associated with poor 5-year survival rates. Thus, there is an urgent need to identify novel biomarkers for early detection, as well as to accurately predict the clinical outcomes and identify effective therapeutic targets for these malignancies. Although the role of lysine acetylation in digestive tract cancers remains unclear, further analysis could improve our understanding of its role in the pathogenesis of digestive tract cancers. This review aims to summarize the implications and pathogenic mechanisms of lysine acetylation dysregulation in digestive tract cancers, as well as its potential clinical applications.

ctDNA responds to neoadjuvant treatment in locally advanced rectal cancer

BACKGROUND

Liquid biopsy is a minimally invasive procedure investigating tumor mutations.

METHODS

In our retrospective study, we investigated whether molecular therapy monitoring of patients receiving neoadjuvant radio(chemo)therapy on a daily routine is possible in 17 patients with locally advanced rectal cancer. Six patients received short-course radiotherapy (5 × 5 Gy) with subsequent surgery, six patients were treated according RAPIDO protocol with short-course radiotherapy followed by chemotherapy (FOLFOX4) and subsequent surgery and five patients received conventional neoadjuvant radiochemotherapy with 5-FU followed by surgery. Response was assessed by Dworak. Liquid biopsies were taken before and immediately after neoadjuvant radiotherapy to isolate and ultradeeply sequence cell free DNA with a panel of 127 genes. Somatic mutations were determined bioinformatically by comparison with normal DNA from leukocytes to distinguish them from germline variants or aging mutations.

RESULTS

In 12 patients (71%) at least one somatic mutation was detected. In 8/12 patients a decrease and in 4/12 an increase or mixed response in ctDNA was seen. Statistical correlation between ctDNA analysis and clinical response could not be seen.

CONCLUSION

ctDNA is responding to neoadjuvant therapy and liquid biopsy is easily integrated into a daily routine. As part of translational research this protocol leaves room for further investigations.

The epigenetic landscape in intestinal stem cells and its deregulation in colorectal cancer

Epigenetic mechanisms play a pivotal role in controlling gene expression and cellular plasticity in both normal physiology and pathophysiological conditions. These mechanisms are particularly important in the regulation of stem cell self-renewal and differentiation, both in embryonic development and within adult tissues. A prime example of this finely tuned epigenetic control is observed in the gastrointestinal lining, where the small intestine undergoes renewal approximately every 3-5 days. How various epigenetic mechanisms modulate chromatin functions in intestinal stem cells (ISCs) is currently an active area of research. In this review, we discuss the main epigenetic mechanisms that control ISC differentiation under normal homeostasis. Furthermore, we explore the dysregulation of these mechanisms in the context of colorectal cancer (CRC) development. By outlining the main epigenetic mechanisms contributing to CRC, we highlight the recent therapeutics development and future directions for colorectal cancer research.

Unraveling the Progression of Colon Cancer Pathogenesis Through Epigenetic Alterations and Genetic Pathways

In the modern age, colon cancer has attained a widespread status, affecting a considerable number of people. It develops due to the progressive accumulation of genetic and epigenetic alterations. While genetic mutations have been extensively studied in the context of colon cancer, emerging evidence highlights the pivotal role of epigenetic alterations in its pathogenesis. These alterations ultimately result in the transformation of normal colonic epithelium into colon adenocarcinoma. Key mechanisms of epigenetic modifications include DNA methylation, histone modification, and nucleosome positioning. Research findings have linked these modifications to the development, progression, or metastasis of tumors. Through the assessment of the colon cancer epigenome, it has been discovered that practically all colorectal cancers (CRCs) display gene methylation abnormalities and changes in miRNA expression. Advancements in this area indicate that epigenetic modifications will likely be commonly used in the near future to direct the prevention and treatment of CRC. The maintenance of genome stability is essential for preserving cellular integrity. The development of CRC is primarily influenced by the loss of genomic stability, which allows for the emergence of new mutations contributing to tumor characteristics. Although genetic mutations have been extensively researched in the realm of colon cancer, recent evidence underscores the pivotal role of epigenetic changes in its pathogenesis. The following types of genomic instability will be discussed: chromosomal instability, microsatellite instability, CpG island methylation phenotype, and aberrant DNA methylation.

Transcriptional co-activators: emerging roles in signaling pathways and potential therapeutic targets for diseases

Specific cell states in metazoans are established by the symphony of gene expression programs that necessitate intricate synergic interactions between transcription factors and the co-activators. Deregulation of these regulatory molecules is associated with cell state transitions, which in turn is accountable for diverse maladies, including developmental disorders, metabolic disorders, and most significantly, cancer. A decade back most transcription factors, the key enablers of disease development, were historically viewed as 'undruggable'; however, in the intervening years, a wealth of literature validated that they can be targeted indirectly through transcriptional co-activators, their confederates in various physiological and molecular processes. These co-activators, along with transcription factors, have the ability to initiate and modulate transcription of diverse genes necessary for normal physiological functions, whereby, deregulation of such interactions may foster tissue-specific disease phenotype. Hence, it is essential to analyze how these co-activators modulate specific multilateral processes in coordination with other factors. The proposed review attempts to elaborate an in-depth account of the transcription co-activators, their involvement in transcription regulation, and context-specific contributions to pathophysiological conditions. This review also addresses an issue that has not been dealt with in a comprehensive manner and hopes to direct attention towards future research that will encompass patient-friendly therapeutic strategies, where drugs targeting co-activators will have enhanced benefits and reduced side effects. Additional insights into currently available therapeutic interventions and the associated constraints will eventually reveal multitudes of advanced therapeutic targets aiming for disease amelioration and good patient prognosis.

Discovery of berberine analogs as potent and highly selective p300/CBP HAT inhibitors

The protein p300 is a positive regulator of cancer progression and is related to many human pathological conditions. To find effective p300/CBP HAT inhibitors, we screened an internal compound library and identified berberine as a lead compound. Next, we designed, synthesized, and screened a series of novel berberine analogs, and discovered that analog 5d was a potent and highly selective p300/CBP HAT inhibitor with IC50 values of 0.070 μM and 1.755 μM for p300 and CBP, respectively. Western blotting further proved that 5d specifically decreased H3K18Ac and interfere with the function of histone acetyltransferase. Although 5d had only a moderate inhibitory effect on the MDA-MB-231 cell line, 5d suppressed the growth of 4T1 tumor growth in mice with a tumor weight inhibition ratio (TWI) of 39.7%. Further, liposomes-encapsulated 5d increased its inhibition of tumor growth to 57.8 % TWI. In addition, 5d has no obvious toxicity to the main organ of mice and the pharmacokinetic study confirmed that 5d has good absorption properties in vivo.

Emerging Role of Epigenetic Modifiers in Breast Cancer Pathogenesis and Therapeutic Response

Breast cancer pathogenesis, treatment, and patient outcomes are shaped by tumor-intrinsic genomic alterations that divide breast tumors into molecular subtypes. These molecular subtypes often dictate viable therapeutic interventions and, ultimately, patient outcomes. However, heterogeneity in therapeutic response may be a result of underlying epigenetic features that may further stratify breast cancer patient outcomes. In this review, we examine non-genetic mechanisms that drive functional changes to chromatin in breast cancer to contribute to cell and tumor fitness and highlight how epigenetic activity may inform the therapeutic response. We conclude by providing perspectives on the future of therapeutic targeting of epigenetic enzymes, an approach that holds untapped potential to improve breast cancer patient outcomes.

A regulatory circuit comprising the CBP and SIRT7 regulates FAM134B-mediated ER-phagy

Macroautophagy (autophagy) utilizes a serial of receptors to specifically recognize and degrade autophagy cargoes, including damaged organelles, to maintain cellular homeostasis. Upstream signals spatiotemporally regulate the biological functions of selective autophagy receptors through protein post-translational modifications (PTM) such as phosphorylation. However, it is unclear how acetylation directly controls autophagy receptors in selective autophagy. Here, we report that an ER-phagy receptor FAM134B is acetylated by CBP acetyltransferase, eliciting intense ER-phagy. Furthermore, FAM134B acetylation promoted CAMKII-mediated phosphorylation to sustain a mode of milder ER-phagy. Conversely, SIRT7 deacetylated FAM134B to temper its activities in ER-phagy to avoid excessive ER degradation. Together, this work provides further mechanistic insights into how ER-phagy receptor perceives environmental signals for fine-tuning of ER homeostasis and demonstrates how nucleus-derived factors are programmed to control ER stress by modulating ER-phagy.

Effects of the Acetyltransferase p300 on Tumour Regulation from the Novel Perspective of Posttranslational Protein Modification

p300 acts as a transcription coactivator and an acetyltransferase that plays an important role in tumourigenesis and progression. In previous studies, it has been confirmed that p300 is an important regulator in regulating the evolution of malignant tumours and it also has extensive functions. From the perspective of non-posttranslational modification, it has been proven that p300 can participate in regulating many pathophysiological processes, such as activating oncogene transcription, promoting tumour cell growth, inducing apoptosis, regulating immune function and affecting embryo development. In recent years, p300 has been found to act as an acetyltransferase that catalyses a variety of protein modification types, such as acetylation, propanylation, butyylation, 2-hydroxyisobutyration, and lactylation. Under the catalysis of this acetyltransferase, it plays its crucial tumourigenic driving role in many malignant tumours. Therefore, the function of p300 acetyltransferase has gradually become a research hotspot. From a posttranslational modification perspective, p300 is involved in the activation of multiple transcription factors and additional processes that promote malignant biological behaviours, such as tumour cell proliferation, migration, and invasion, as well as tumour cell apoptosis, drug resistance, and metabolism. Inhibitors of p300 have been developed and are expected to become novel anticancer drugs for several malignancies. We review the characteristics of the p300 protein and its functional role in tumour from the posttranslational modification perspective, as well as the current status of p300-related inhibitor research, with a view to gaining a comprehensive understanding of p300.

The role of protein acetylation in carcinogenesis and targeted drug discovery

Protein acetylation is a reversible post-translational modification, and is involved in many biological processes in cells, such as transcriptional regulation, DNA damage repair, and energy metabolism, which is an important molecular event and is associated with a wide range of diseases such as cancers. Protein acetylation is dynamically regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs) in homeostasis. The abnormal acetylation level might lead to the occurrence and deterioration of a cancer, and is closely related to various pathophysiological characteristics of a cancer, such as malignant phenotypes, and promotes cancer cells to adapt to tumor microenvironment. Therapeutic modalities targeting protein acetylation are a potential therapeutic strategy. This article discussed the roles of protein acetylation in tumor pathology and therapeutic drugs targeting protein acetylation, which offers the contributions of protein acetylation in clarification of carcinogenesis, and discovery of therapeutic drugs for cancers, and lays the foundation for precision medicine in oncology.

Epigenetics and its therapeutic potential in colorectal cancer

It is estimated that colorectal cancer (CRC) is the leading cause of cancer-related death around the globe. 'Epigenetics' refers to changes in the chromosome rather than the DNA sequence, which may be transmitted down to daughter cells. Epigenetics is an essential part of controlling the development and variation of a single cell. ncRNAs have a role in epigenetic regulation in CRC, which will be discussed in this review in the context of DNA methylation and histone modifications. A greater survival rate for CRC patients might be achieved by addressing epigenetic mediators, as the authors show. In this review, they aim to thoroughly examine the role of epigenetics in the prognosis, diagnosis and treatment of CRC.

The role of epigenetic modifications in Colorectal Cancer Metastasis

Distant metastasis is the major contributor to the high mortality rate of colorectal cancer (CRC). To overcome the poor prognosis caused by distant metastasis, the mechanisms of CRC metastasis should be further explored. Epigenetic events are the main mediators of gene regulation and further affect tumor progression. Recent studies have found that some epigenetic enzymes are often dysregulated or mutated in multiple tumor types, which prompted us to study the roles of these enzymes in CRC metastasis. In this review, we summarized the alteration of enzymes related to various modifications, including histone modification, nonhistone modification, DNA methylation, and RNA methylation, and their epigenetic mechanisms during the progression of CRC metastasis. Existing data suggest that targeting epigenetic enzymes is a promising strategy for the treatment of CRC metastasis.

Selenium-Based Novel Epigenetic Regulators Offer Effective Chemotherapeutic Alternative with Wider Safety Margins in Experimental Colorectal Cancer

Colorectal cancer (CRC) is a major cause of morbidity and mortality worldwide. Despite the critical involvement of epigenetic modifications in CRC, the studies on the chemotherapeutic efficacy of various epigenetic regulators remain limited. Considering the key roles of histone deacetylases (HDACs) in the regulation of diverse cellular processes, several HDAC inhibitors are implied as effective therapeutic strategies. In this context, suberoylanilide hydroxamic acid (SAHA), a 2^nd-generation HDAC inhibitor, showed limited efficacy in solid tumors. Also, side effects associated with SAHA limit its clinical application. Based on the redox-modulatory and HDAC inhbitiory activities of essential trace element selenium (Se), the anti-carcinogenic potential of Se substituted SAHA, namely, SelSA-1 (25 mg kg^-1), was screened for it enhanced anti-tumorigenic role and wider safety profiles in DMH-induced CRC in Balb/c mice. A multipronged approach such as in silico, biochemical, and pharmacokinetics (PK) has been used to screen, characterize, and evaluate these novel compounds in comparison to existing HDAC inhibitor SAHA. This is the first in vivo study indicating the chemotherapeutic potential of Se-based novel epigenetic regulators such as SelSA-1 in any in vivo experimental model of carcinogenesis. Pharmcological and toxicity data indicated better safety margins, bioavailability, tolerance, and elimination rate of SelSA-1 compared to classical HDAC inhibitor SAHA. Further, histological and morphological evidence demonstrated enhanced chemotherapeutic potential of SelSA-1 even at lower pharmacological doses than SAHA. This is the first in vivo study suggesting Se-based novel epigenetic regulators as potential chemotherapeutic alternatives with wider safety margins and enhanced anticancer activities.

Lysine Acetylation, Cancer Hallmarks and Emerging Onco-Therapeutic Opportunities

Simple Summary

Several histone deacetylase inhibitors have been approved by FDA for cancer treatment. Intensive efforts have been devoted to enhancing its anti-cancer efficacy by combining it with various other agents. Yet, no guideline is available to assist in the choice of candidate drugs for combination towards optimal solutions for different clinical problems. Thus, it is imperative to characterize the primary cancer hallmarks that lysine acetylation is associated with and gain knowledge on the key cancer features that each combinatorial onco-therapeutic modality targets to aid in the combinatorial onco-therapeutic design. Cold atmospheric plasma represents an emerging anti-cancer modality via manipulating cellular redox level and has been demonstrated to selectively target several cancer hallmarks. This review aims to delineate the intrinsic connections between lysine acetylation and cancer properties, and forecast opportunities histone deacetylase inhibitors may have when combined with cold atmospheric plasma as novel precision onco-therapies.

Abstract

Acetylation, a reversible epigenetic process, is implicated in many critical cellular regulatory systems including transcriptional regulation, protein structure, activity, stability, and localization. Lysine acetylation is the most prevalent and intensively investigated among the diverse acetylation forms. Owing to the intrinsic connections of acetylation with cell metabolism, acetylation has been associated with metabolic disorders including cancers. Yet, relatively little has been reported on the features of acetylation against the cancer hallmarks, even though this knowledge may help identify appropriate therapeutic strategies or combinatorial modalities for the effective treatment and resolution of malignancies. By examining the available data related to the efficacy of lysine acetylation against tumor cells and elaborating the primary cancer hallmarks and the associated mechanisms to target the specific hallmarks, this review identifies the intrinsic connections between lysine acetylation and cancer hallmarks and proposes novel modalities that can be combined with HDAC inhibitors for cancer treatment with higher efficacy and minimum adverse effects.

Epigenetic Modulators as Treatment Alternative to Diverse Types of Cancer

DNA is packaged in rolls in an octamer of histones forming a complex of DNA and proteins called chromatin. Chromatin as a structural matrix of a chromosome and its modifications are nowadays considered relevant aspects for regulating gene expression, which has become of high interest in understanding genetic mechanisms regulating various diseases, including cancer. In various types of cancer, the main modifications are found to be DNA methylation in the CpG dinucleotide as a silencing mechanism in transcription, post-translational histone modifications such as acetylation, methylation and others that affect the chromatin structure, the ATP-dependent chromatin remodeling and miRNA-mediated gene silencing. In this review we analyze the main alterations in gene expression, the epigenetic modification patterns that cancer cells present, as well as the main modulators and inhibitors of each epigenetic mechanism and the molecular evolution of the most representative inhibitors, which have opened a promising future in the study of HAT, HDAC, non-glycoside DNMT inhibitors and domain inhibitors.

Autophagy Upregulates miR-449a Expression to Suppress Progression of Colorectal Cancer

Many studies reported that microRNAs (miRNAs) target autophagy-related genes to affect carcinogenesis, however, autophagy-deficiency-related miRNA dysfunction in cancer development remains poorly explored. During autophagic progression, we identified miR-449a as the most up-regulated miRNA. MiR-449a expression was low in the tumor parts of CRC patient specimens and inversely correlated with tumor stage and metastasis with the AUC (area under the curve) of 0.899 and 0.736 as well as poor overall survival rate, indicating that miR-449a has the potential to be a prognostic biomarker. In the same group of CRC specimens, low autophagic activity (low Beclin 1 expression and high p62 accumulation) was detected, which was significantly associated with miR-449a expression. Mechanistic studies disclosed that autophagy upregulates miR-449a expression through degradation of the coactivator p300 protein which acetylates the transcription factor Forkhead Box O1 (FoxO1). Unacetylated FoxO1 translocated to the nucleus and bound to the miR-449a promoter to drive gene expression. Either activation of autophagy by the inducer or overexpression of exogenous miR-449a decreases the expression of target gene LEF-1 and cyclin D1, which lead to decreased proliferation, colony formation, migration, and invasion of CRC cells. Autophagy-miR-449a-tartet genes mediated suppression of tumor formation was further confirmed in the xenograft mouse model. In conclusion, this study reveals a novel mechanism wherein autophagy utilizes miR-449a-LEF1-cyclin D1 axis to suppress CRC tumorigenesis. Our findings open a new avenue toward prognosis and treatment of CRC patients by manipulating autophagy-miR-449a axis.

Carnosol Is a Novel Inhibitor of p300 Acetyltransferase in Breast Cancer

Carnosol, a natural polyphenol abundant in edible plants such as sage, rosemary, and oregano, has shown promising anticancer activity against various types of cancers. Nonetheless, very little is known about its molecular mechanism of action or its downstream target(s). We have previously shown that carnosol inhibits cellular proliferation, migration, invasion, and metastasis as well as triggers autophagy and apoptosis in the highly invasive MDA-MB-231 breast cancer cells. Here, we report that carnosol induces histone hypoacetylation in MDA-MB-231 and Hs578T breast cancer cells. We show that, while carnosol does not affect HDACs, it promotes a ROS-dependent proteasome degradation of p300 and PCAF histone acetyl transferases (HATs) without affecting other HATs such as GCN5 and hMOF. Carnosol-induced histone hypoacetylation remains persistent even when p300 and PCAF protein levels were rescued from degradation by (i) the inhibition of the proteasome activity by the proteasome inhibitors MG-132 and bortezomib, and (ii) the inhibition of ROS accumulation by the ROS scavenger, N-acetylcysteine. In addition, we report that, in a cell-free system, carnosol efficiently inhibits histone acetyltransferase activity of recombinant p300 but not that of PCAF or GCN5. Molecular docking studies reveal that carnosol inhibits p300 HAT activity by blocking the entry of the acetyl-CoA binding pocket of the catalytic domain. The superimposition of the docked conformation of the p300 HAT domain in complex with carnosol shows a similar orientation as the p300 structure with acetyl-CoA. Carnosol occupies the region where the pantetheine arm of the acetyl-CoA is bound. This study further confirms carnosol as a promising anti-breast cancer therapeutic compound and identifies it as a novel natural p300 inhibitor that could be added to the existing panel of inhibitors.

The impact of CBP expression in estrogen receptor-positive breast cancer

Background

The development of new biomarkers with diagnostic, prognostic and therapeutic prominence will greatly enhance the management of breast cancer (BC). Several reports suggest the involvement of the histone acetyltransferases CREB-binding protein (CBP) and general control non-depressible 5 (GCN5) in tumor formation; however, their clinical significance in BC remains poorly understood. This study aims to investigate the value of CBP and GCN5 as markers and/or targets for BC prognosis and therapy. Expression of CBP, GCN5, estrogen receptor α (ERα), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) in BC was analyzed in cell lines by western blot and in patients’ tissues by immunohistochemistry. The gene amplification data were also analyzed for CBP and GCN5 using the publicly available data from BC patients.

Results

Elevated expression of CBP and GCN5 was detected in BC tissues from patients and cell lines more than normal ones. In particular, CBP was more expressed in luminal A and B subtypes. Using chemical and biological inhibitors for CBP, ERα and HER2 showed a strong association between CBP and the expression of ERα and HER2. Moreover, analysis of the CREBBP (for CBP) and KAT2A (for GCN5) genes in a larger number of patients in publicly available databases showed amplification of both genes in BC patients. Amplification of CREBBP gene was observed in luminal A, luminal B and triple-negative but not in HER2 overexpressing subtypes. Furthermore, patients with high CREBBP or KAT2A gene expression had better 5-year disease-free survival than the low gene expression group (p = 0.0018 and p < 0.00001, respectively).

Conclusions

We conclude that the persistent amplification and overexpression of CBP in ERα- and PR-positive BC highlights the significance of CBP as a new diagnostic marker and therapeutic target in hormone-positive BC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01060-2.

Critical regulatory levels in tumor differentiation: Signaling pathways, epigenetics and non-coding transcripts

Approaches to induce tumor differentiation often result in manageable and therapy-naïve cellular states in cancer cells. This transformation is achieved by activating pathways that drive tumor cells away from plasticity, a state that commonly correlates with enhanced aggression, metastasis and resistance to therapy. Here, we discuss signaling pathways, epigenetics and non-coding RNAs as three main regulatory levels with the potential to drive tumor differentiation and hence as potential targets in differentiation therapy approaches. The success of an effective therapeutic regimen in one cancer, however, does not necessarily sustain across cancer types; a phenomenon largely resulting from heterogeneity in the genetic and physiological landscapes of tumor types necessitating an approach designed for each cancer's unique genetic and phenotypic build-up.

New Insights into Mechanisms of Endocrine-Disrupting Chemicals in Thyroid Diseases: The Epigenetic Way

In recent years, the presence in the environment of chemical compounds with thyroid-disrupting effects is progressively increased. This phenomenon has risen concern for human health as the preservation of thyroid system homeostasis is essential for fetal development and for maintaining psychological and physiological wellbeing. An increasing number of studies explored the role of different classes of toxicants in the occurrence and severity of thyroid diseases, but large epidemiological studies are limited and only a few animal or in vitro studies have attempted to identify the mechanisms of chemical action. Recently, epigenetic changes such as alteration of methylation status or modification of non-coding RNAs have been suggested as correlated to possible deleterious effects leading to different thyroid disorders in susceptible individuals. This review aims to analyze the epigenetic alterations putatively induced by chemical exposures and involved in the onset of frequent thyroid diseases such as thyroid cancer, autoimmune thyroiditis and disruption of fetal thyroid homeostasis.

Stress granules in colorectal cancer: Current knowledge and potential therapeutic applications

Stress granules (SGs) represent important non-membrane cytoplasmic compartments, involved in cellular adaptation to various stressful conditions (e.g., hypoxia, nutrient deprivation, oxidative stress). These granules contain several scaffold proteins and RNA-binding proteins, which bind to mRNAs and keep them translationally silent while protecting them from harmful conditions. Although the role of SGs in cancer development is still poorly known and vary between cancer types, increasing evidence indicate that the expression and/or the activity of several key SGs components are deregulated in colorectal tumors but also in pre-neoplastic conditions (e.g., inflammatory bowel disease), thus suggesting a potential role in the onset of colorectal cancer (CRC). It is therefore believed that SGs formation importantly contributes to various steps of colorectal tumorigenesis but also in chemoresistance. As CRC is the third most frequent cancer and one of the leading causes of cancer mortality worldwide, development of new therapeutic targets is needed to offset the development of chemoresistance and formation of metastasis. Abolishing SGs assembly may therefore represent an appealing therapeutic strategy to re-sensitize colon cancer cells to anti-cancer chemotherapies. In this review, we summarize the current knowledge on SGs in colorectal cancer and the potential therapeutic strategies that could be employed to target them.

Identification of novel biomarkers and small-molecule compounds for nasopharyngeal carcinoma with metastasis

The purpose of this study was to investigate novel biomarkers and potential mechanisms in nasopharyngeal carcinoma (NPC) patients with metastasis.Two microarray datasets (GSE103611 and GSE36682) were obtained from GEO database, differentially expressed genes (DEGs) and differentially expressed miRNA (DEMs) were identified, Gene ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted with DEGs and DEMs targeted genes. Protein-protein interactions (PPI) network of the DEGs and DEMs targeted genes were constructed, furthermore, Connectivity Map (CMap) database was applied to select the potential drugs with therapeutic effects.Overall, we identified 396 upregulated and 19 downregulated DEGs. Additionally, we identified 1 upregulated DEM, miR-135b, and a downregulated DEM, miR-574-5p. Functional enrichment analysis indicated that both DEGs and DEMs targeted genes participated in biological process (BP) of regulation of transcription from RNA polymerase II promoter, DNA-templated positive regulation of transcription, and Epstein-Barr virus infection signaling pathway. Besides, upregulated EP300 gene was a hub node both in DEGs and DEMs target genes. CMap database analysis indicated that sanguinarine, verteporfin, and chrysin are potential drugs for prevention and treatment of NPC metastasis.In summary, the common hub gene, biological process and pathway identified in the study provided a novel insight into the potential mechanism of NPC metastasis. Furthermore, we identified several possible small molecule compounds for treatment of NPC metastasis.

HISTome2: a database of histone proteins, modifiers for multiple organisms and epidrugs

BACKGROUND

Epigenetics research is progressing in basic, pre-clinical and clinical studies using various model systems. Hence, updating the knowledge and integration of biological data emerging from in silico, in vitro and in vivo studies for different epigenetic factors is essential. Moreover, new drugs are being discovered which target various epigenetic proteins, tested in pre-clinical studies, clinical trials and approved by the FDA. It brings distinct challenges as well as opportunities to update the existing HIstome database for implementing and applying enormous data for biomedical research.

RESULTS

HISTome2 focuses on the sub-classification of histone proteins as variants and isoforms, post-translational modifications (PTMs) and modifying enzymes for humans (Homo sapiens), rat (Rattus norvegicus) and mouse (Mus musculus) on one interface for integrative analysis. It contains 232, 267 and 350 entries for histone proteins (non-canonical/variants and canonical/isoforms), PTMs and modifying enzymes respectively for human, rat, and mouse. Around 200 EpiDrugs for various classes of epigenetic modifiers, their clinical trial status, and pharmacological relevance have been provided in HISTome2. The additional features like 'Clustal omega' for multiple sequence alignment, link to 'FireBrowse' to visualize TCGA expression data and 'TargetScanHuman' for miRNA targets have been included in the database.

CONCLUSION

The information for multiple organisms and EpiDrugs on a common platform will accelerate the understanding and future development of drugs. Overall, HISTome2 has significantly increased the extent and diversity of its content which will serve as a 'knowledge Infobase' for biologists, pharmacologists, and clinicians. HISTome2: The HISTone Infobase is freely available on http://www.actrec.gov.in/histome2/ .

A novel histone acetyltransferase inhibitor A485 improves sensitivity of non-small-cell lung carcinoma cells to TRAIL

Transcriptional coactivators p300 and CBP catalyze the acetylation of lysine residues in histone proteins. Upregulation of p300 and CBP has been associated with lung, colorectal and hepatocellular cancer, indicating an important role of p300 and CBP in tumorigenesis. Recently, the novel p300 and CBP-selective inhibitor A485 became available, which was shown to inhibit proliferation of 124 different cancer cell lines. Here, we found that downregulation of EP300 or CREBBP enhances apoptosis upon TRAIL stimulation in non-small-cell lung cancer (NSCLC) cells. A485 upregulates pro- and anti-apoptotic genes at the mRNA level, implying an apoptosis-modulating effect in NSCLC cells. However, A485 alone does not induce apoptosis. Interestingly, we observed that the number of apoptotic cells increases upon combined treatment with A485 and TRAIL. Therefore, A485, as a TRAIL-sensitizer, was used in combination with TRAIL in wild type of NSCLC cell lines (HCC827 and H1650) and cells with acquired erlotinib resistance (HCC827-ER and H1650-ER). Our results show that the combination of A485 and TRAIL synergistically increases cell death and inhibits long-term cell proliferation. Furthermore, this combination inhibits the growth of 3D spheroids of EGFR-TKI-resistant cells. Taken together, we demonstrate a successful combination of A485 and TRAIL in EGFR-TKI-sensitive and resistant NSCLC cells.

EGFR-vIII downregulated H2AZK4/7AC though the PI3K/AKT-HDAC2 axis to regulate cell cycle progression

BACKGROUND

The EGFR-vIII mutation is the most common malignant event in GBM. Epigenetic reprogramming in EGFR-activated GBM has recently been suggested to downregulate the expression of tumour suppressor genes. Histone acetylation is important for chromatin structure and function. However, the role and biological function of H2AZK4/7AC in tumours have not yet been clarified.

RESULTS

In our study, we found that EGFR-vIII negatively regulated H2AZK4/7AC expression though the PI3K/AKT-HDAC2 axis. Because HDAC1 and HDAC2 are highly homologous enzymes that usually form multi-protein complexes for transcriptional regulation and epigenetic landscaping, we simultaneously knocked out HDAC1 and HDAC2 and found that H2AZK4/7AC and H3K27AC were upregulated, which partially released EGFR-vIII-mediated inhibition of USP11, negative regulator of cell cycle. In addition, we demonstrated in vitro and in vivo that FK228 induced G1/S transition arrest in GBM with EGFR-vIII mutation. FK228 could enhance anti-tumour activity by upregulating expression of the tumour suppressor USP11 in GBM cells.

CONCLUSIONS

EGFR-vIII mutation downregulates H2AZK4/7AC and H3K27AC, inhibiting USP11 expression though the PI3K/AKT-HDAC1/2 axis. FK228 is an effective and promising treatment for GBM with EGFR-vIII mutation.

The prognostic capacities of CBP and p300 in locally advanced rectal cancer

Background

CREB-binding protein (CBP) and p300 represent histone acetyltransferases (HATs) and transcriptional coactivators that play essential roles in tumour initiation and progression. Both proteins are generally thought to function as tumour suppressors, although their distinct roles in colorectal cancer (CRC) remain inconsistent and ambiguous.

Thus, we analysed the expression of these two HATs in human tissue samples from patients with locally advanced rectal cancer via immunohistochemistry and evaluated their potential impacts on future CRC diagnosis and treatment.

Methods

In our analysis, we included ninety-three (n = 93) patients diagnosed with adenocarcinoma in the upper third of the rectum. None of the patients received preoperative chemoradiotherapy, but the patients did undergo primary resection of the tumour within the phase II GAST-05 trial. By using H-scores, the expression of both proteins was visualised via immunohistochemistry in resected specimens from the patients. CBP and p300 expression were correlated with clinical and follow-up data.

Results

Our analysis showed that high expression of CBP was significantly associated with prolonged cancer-specific survival (CSS; p = 0.002). In univariate analysis, CBP was an independent prognostic parameter for CSS (p = 0.042). High nuclear CBP expression was observed in two-thirds of patients. In contrast, we could not find any significant correlation between the expression of p300 and cancer-specific survival in this cohort of patients (p = 0.09). We did not observe any cooperation between CBP and p300 in our analysis.

Conclusions

High expression of CBP was significantly associated with improved oncological outcomes. This finding could help to stratify patients in the future for CRC treatment. Histone deacetylase (HDAC) inhibitors are increasingly playing a role in oncological treatment and could additionally become therapeutic options in CRC. Our findings need to be further evaluated and verified in future clinical analyses.

A Comparative Study of Target Engagement Assays for HDAC1 Inhibitor Profiling

Histone deacetylases (HDACs) are epigenetic modulators linked to diseases including cancer and neurodegeneration. Given their therapeutic potential, highly sensitive biochemical and cell-based profiling technologies have been developed to discover small-molecule HDAC inhibitors. Ultimately, the therapeutic action of these inhibitors is dependent on a physical engagement with their intended targets in cellular and tissue environments. Confirming target engagement in the cellular environment is particularly relevant for HDACs since they function as part of cell type-specific multiprotein complexes. Here we implemented two recently developed high-throughput target engagement technologies, NanoBRET and SplitLuc CETSA, to profile 349 compounds in the Epigenetic-Focused collection for HDAC1 binding. We found that the two HDAC1 target engagement assays correlated well with each other and with orthogonal activity-based assays, in particular those carried out in cellular environments rather than with isolated HDAC proteins. The assays detected a majority of the previously described HDAC1 inhibitors in the collection and, importantly, triaged HDAC inhibitors known to target other HDACs.

Synergistic Effect of Epigenetic Inhibitors Decitabine and Suberoylanilide Hydroxamic Acid on Colorectal Cancer In vitro

Background:

Colorectal Cancer (CRC) is a common cause of oncological deaths worldwide. Alterations of the epigenetic landscape constitute a well-documented hallmark of CRC phenotype. The accumulation of aberrant DNA methylation and histone acetylation plays a major role in altering gene activity and driving tumor onset, progression and metastasis.

Objective:

In this study, we evaluated the effect of Suberoylanilide Hydroxamic Acid (SAHA), a panhistone deacetylase inhibitor, and Decitabine (DAC), a DNA methyltransferase inhibitor, either alone or in combination, on Caco-2 human colon cancer cell line in vitro.

Results:

Our results showed that SAHA and DAC, separately, significantly decreased cell proliferation, induced apoptosis and cell cycle arrest of Caco-2 cell line. On the other hand, the sequential treatment of Caco-2 cells, first with DAC and then with SAHA, induced a synergistic anti-tumor effect with a significant enhancement of growth inhibition and apoptosis induction in Caco-2 cell line as compared to cells treated with either drug alone. Furthermore, the combination therapy upregulates protein expression levels of pro-apoptotic proteins Bax, p53 and cytochrome c, downregulates the expression of antiapoptotic Bcl-2 protein and increases the cleavage of procaspases 8 and 9; this suggests that the combination activates apoptosis via both the intrinsic and extrinsic pathways. Mechanistically, we demonstrated that the synergistic anti-neoplastic activity of combined SAHA and DAC involves an effect on PI3K/AKT and Wnt/β-catenin signaling.

Conclusion:

In conclusion, our results provide evidence for the profound anti-tumorigenic effect of sequentially combined SAHA and DAC in the CRC cell line and offer new insights into the corresponding underlined molecular mechanism.

EP300 as an oncogene correlates with poor prognosis in esophageal squamous carcinoma

E1A Binding Protein P300 (EP300) is one of the mutations of genes involved in histone modifications in esophageal squamous cell carcinoma (ESCC). However, its clinical relevance, potential function and mechanisms have remained elusive.

Methods: Genomic sequencing datas from 325 esophageal squamous cell carcinoma (ESCC) cases were integrated and screened a series of frequently mutated histone modifier genes. EP300 was selected to further analyze its clinical significance, function and RNA-sequencing was performed to explore its potential mechanism.

Results: Of 35 histone modifier genes, EP300 was not only a significantly mutated gene but also a frequently mutated gene with a mutation frequency of more than 10% in ESCC. EP300 mutation was associated with tumor grade, pathological T stage and lymph node metastasis, predicting a shorter cumulative survival status. Immunohistochemical analysis showed that EP300 expression was significantly higher in ESCC tumor tissues, and the expression levels were associated with poor survival of ESCC patients. Moreover, we found that EP300 knockdown led to inhibition of cell proliferation, colony formation, migration and invasion. RNA-sequencing showed EP300 knockdown led to a significant change of genes expression associated with angiogenesis, hypoxia and epithelial-to-mesenchymal transition (EMT).

Conclusions: Taken together, our study identified a novel role and mechanism of EP300 in ESCC and provided epigenetic therapeutic strategies for the treatment of ESCC.

Prognostic role of upregulated P300 expression in human cancers: A clinical study of synovial sarcoma and a meta-analysis

E1A binding protein p300 (P300) is a member of the histone acetyltransferase family of transcriptional co-activators, which are associated with various types of cancer. Numerous studies have evaluated the diagnostic value of P300, but their results are not consistent. Therefore, a clinical study and a meta-analysis were performed in the present study to investigate the prognostic value of P300 expression in human malignant neoplasms. Immunohistochemical (IHC) analysis was used to assess P300 expression in 43 paraffin-embedded primary synovial sarcoma (SS) samples. For the meta-analysis, eligible studies published until January 21, 2018 were identified by searching the PubMed, EMBASE and Web of Science databases. The IHC analysis indicated a high P300 expression rate in 33.3% (10/30) of biphasic SS (BSSs) and in 60% (6/10) of monophasic fibrous SS tissues. In BSS, the expression rate was significantly higher in the epithelial component (80.0%, 24/30) than that in the spindle-cell component (30.0%, 9/30; P<0.05). The meta-analysis indicated that high expression of P300 was associated with poor overall survival (OS) in digestive system malignant neoplasms (HR=1.54, 95% CI: 1.20-2.23), as well as with poor progression-free survival, recurrence-free survival and disease-free survival combined (HR=1.84, 95% CI: 1.36-2.47). Analysis of subgroups by ethnicity demonstrated that high expression of P300 was associated with poor OS in Asians (HR=1.72, 95% CI: 1.20-2.47) but favourable OS in Caucasians (HR=0.59, 95% CI: 0.47-0.73). Furthermore, high expression of P300 was associated with clinical stage [Relative Risk (RR)=1.30, 95% CI: 1.07-1.58], lymph node metastasis (RR=1.30, 95% CI: 1.03-1.64) and depth of invasion (RR=1.31, 95% CI: 1.07-1.60). P300 expression may therefore be a useful biomarker for predicting patient prognosis in various types of human cancer.

MYC competes with MiT/TFE in regulating lysosomal biogenesis and autophagy through an epigenetic rheostat

Coordinated regulation of the lysosomal and autophagic systems ensures basal catabolism and normal cell physiology, and failure of either system causes disease. Here we describe an epigenetic rheostat orchestrated by c-MYC and histone deacetylases that inhibits lysosomal and autophagic biogenesis by concomitantly repressing the expression of the transcription factors MiT/TFE and FOXH1, and that of lysosomal and autophagy genes. Inhibition of histone deacetylases abates c-MYC binding to the promoters of lysosomal and autophagy genes, granting promoter occupancy to the MiT/TFE members, TFEB and TFE3, and/or the autophagy regulator FOXH1. In pluripotent stem cells and cancer, suppression of lysosomal and autophagic function is directly downstream of c-MYC overexpression and may represent a hallmark of malignant transformation. We propose that, by determining the fate of these catabolic systems, this hierarchical switch regulates the adaptive response of cells to pathological and physiological cues that could be exploited therapeutically.

Genes related to lysosomal and autophagic systems are transcriptionally regulated by the Mit/TFE family of transcription factors. Here the authors show that MYC, in association with HDACs, suppresses the expression of lysosomal and autophagy genes by competing with the Mit/TFE transcription factors for occupancy of their target gene promoters.

p53 at the Crossroads between Different Types of HDAC Inhibitor-Mediated Cancer Cell Death

Cancer is a complex genetic and epigenetic-based disease that has developed an armada of mechanisms to escape cell death. The deregulation of apoptosis and autophagy, which are basic processes essential for normal cellular activity, are commonly encountered during the development of human tumors. In order to assist the cancer cell in defeating the imbalance between cell growth and cell death, histone deacetylase inhibitors (HDACi) have been employed to reverse epigenetically deregulated gene expression caused by aberrant post-translational protein modifications. These interfere with histone acetyltransferase- and deacetylase-mediated acetylation of both histone and non-histone proteins, and thereby exert a wide array of HDACi-stimulated cytotoxic effects. Key determinants of HDACi lethality that interfere with cellular growth in a multitude of tumor cells are apoptosis and autophagy, which are either mutually exclusive or activated in combination. Here, we compile known molecular signals and pathways involved in the HDACi-triggered induction of apoptosis and autophagy. Currently, the factors that determine the mode of HDACi-elicited cell death are mostly unclear. Correspondingly, we also summarized as yet established intertwined mechanisms, in particular with respect to the oncogenic tumor suppressor protein p53, that drive the interplay between apoptosis and autophagy in response to HDACi. In this context, we also note the significance to determine the presence of functional p53 protein levels in the cancer cell. The confirmation of the context-dependent function of autophagy will pave the way to improve the benefit from HDACi-mediated cancer treatment.

DNA methylation and chromatin modifiers in colorectal cancer

Colorectal carcinogenesis is a multistep process involving the accumulation of genetic alterations over time that ultimately leads to disease progression and metastasis. Binding of transcription factors to gene promoter regions alone cannot explain the complex regulation pattern of gene expression during this process. It is the chromatin structure that allows for a high grade of regulatory flexibility for gene expression. Posttranslational modifications on histone proteins such as acetylation, methylation, or phosphorylation determine the accessibility of transcription factors to DNA. DNA methylation, a chemical modification of DNA that modulates chromatin structure and gene transcription acts in concert with these chromatin conformation alterations. Another epigenetic mechanism regulating gene expression is represented by small non-coding RNAs. Only very recently epigenetic alterations have been included in molecular subtype classification of colorectal cancer (CRC). In this chapter, we will provide examples of the different epigenetic players, focus on their role for epithelial-mesenchymal transition and metastatic processes and discuss their prognostic value in CRC.

Histone deacetylase-mediated regulation of the antimicrobial peptide hBD2 differs in intestinal cell lines and cultured tissue

Histone deacetylase inhibition (HDACi) has been suggested as a promising approach to bolster TLR-mediated induction of antimicrobial peptides such as human β-defensin 2 (hBD2). In inflammatory bowel disease (IBD), Crohn’s disease (CD) patients display an attenuated expression of hBD2 as compared to ulcerative colitis (UC). Here, we aimed to study if combining HDACi with the therapeutic E. coli Nissle 1917 (EcN), a strong hBD2 inducer, might be a feasible strategy to further modify protective immune responses. Monolayer epithelial cell lines versus cultured human biopsies from healthy controls and CD and UC patients showed diverse effects. In mono-cell systems, we observed a strong NF-kB-dependent enhancement of TLR- but also IL1β-mediated hBD2 induction after HDACi. In contrast, multicellular colonic biopsy culture showed the opposite result and HDACi was associated with an abolished TLR-mediated hBD2 induction in all tested patient groups. Of note, CD patients showed an attenuated induction of hBD2 by E. coli Nissle as compared to UC. We conclude that the role of HDACs in hBD2 regulation is context-dependent and likely modified by different cell types. Differential induction in different IBD entities suggests different clinical response patterns based on still unknown hBD2-associated mechanisms.

The expression of histone deacetylase HDAC1 correlates with the progression and prognosis of gastrointestinal malignancy

Gastrointestinal malignancy is a severe public health threat worldwide, and survival for most types of gastrointestinal cancer is very poor. Therefore, finding better cancer biomarkers to diagnose gastrointestinal malignancy and predict patient survival is essential. HDAC1 has been reported to be closely associated with several types of cancer, but the precise role of HDAC1 in gastrointestinal cancer is not clear. Recently, quite a few studies have investigated the correlation between HDAC1 expression and clinical features or prognosis in multiple types of gastrointestinal malignancies, but the results were inconsistent. In this study, we systematically reviewed the association between HDAC1 and gastrointestinal malignancy using meta-analysis methods, and 28 eligible studies were analyzed. We found that the expression level of HDAC1 in gastrointestinal malignancies, especially in colorectal cancer (OR = 10.84, 95% CI = 5.33-22.07, P< 0.00001), was higher than that in noncancerous tissue, and HDAC1 expression was closely associated with some clinical features of gastrointestinal cancer patients, such as tumor stage (OR = 1.62, 95% CI = 1.28-2.05, P < 0.0001) and tumor grade (OR = 1.75, 95% CI = 1.03-2.95, P = 0.04). In addition, we also found that patients with low HDAC1 expression showed better overall survival than those with high HDAC1 expression in gastrointestinal malignancy, especially in gastric cancer (HR = 1.88, 95% CI = 1.14-3.12, P = 0.01). Our results strongly suggest that HDAC1 may serve as a good diagnostic and prognostic marker for gastrointestinal malignancy.

P300 inhibition enhances gemcitabine-induced apoptosis of pancreatic cancer

The transcriptional cofactor p300 has histone acetyltransferase activity (HAT) and has been reported to participate in chromatin remodeling and DNA repair. We hypothesized that targeting p300 can enhance the cytotoxicity of gemcitabine, which induces pancreatic cancer cell apoptosis by damaging DNA. Expression of p300 was confirmed in pancreatic cancer cell lines and human pancreatic adenocarcinoma tissues by western blotting and immunohistochemistry. When pancreatic cancer cells were treated with gemcitabine, p300 was recruited to chromatin within 24 hours, indicating the role in response to DNA damage. When p300 was gene-silenced with siRNA, histone acetylation was substantially reduced and pancreatic cancer cells were sensitized to gemcitabine. The selective p300 HAT inhibitor C646 similarly decreased histone acetylation, increased gemcitabine-induced apoptosis and thus enhanced the cytotoxicity of gemcitabine on pancreatic cancer cells. These findings indicate that p300 contributes to chemo-resistance of pancreatic cancer against gemcitabine and suggest that p300 and its HAT activity may be a potential therapeutic target to improve outcomes in patients with pancreatic cancer.

Investigation of the changes in the expression levels of MOZ gene in colorectal cancer tissues

Background

MOZ is one of the most important histone acetyltransferases (HATs) that has an effective role in gene expression. It is an important partner in chromosomal rearrangement that usually occurs in hematological malignancies such as leukemia. Besides these malignancies, its role in solid tumors has been reported. In the present study, we aimed to quantify of MOZ messenger RNA (mRNA) expression in colorectal cancer (CRC) tissues from a northwest population of Iran and consequently to assess the effect of MOZ in CRC.

Methods

Tumorous and adjacent non-tumorous tissues recruited from 26 patients with CRC. mRNA extraction and complementary DNA (cDNA) synthesis were performed from these tissues, at the next step quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) was carried out. Finally, expression levels were statistically analyzed using IBM SPSS Statistics 24.0 software and independent t-test. Statistical significance was considered as P≤0.05.

Results

The results showed significantly higher expression of MOZ in the majority of CRC tissues compared to normal colorectal tissues (P=0.048). There were no significant correlations between expression levels of MOZ and clinical parameters of patients (P>0.05).

Conclusions

Our data showed that dysregulation of MOZ is potentially involved in the pathogenesis of CRC and we could suggest that there is a straight relationship between tumor formation and MOZ expression. These results showed possible role of MOZ as a prognostic factor in the said population.

Pediatric Anaplastic Embryonal Rhabdomyosarcoma: Targeted Therapy Guided by Genetic Analysis and a Patient-Derived Xenograft Study

Therapy for rhabdomyosarcoma (RMS) has generally been limited to combinations of conventional cytotoxic agents similar to regimens originally developed in the late 1960s. Recently, identification of molecular alterations through next-generation sequencing of individual tumor specimens has facilitated the use of more targeted therapeutic approaches for various malignancies. Such targeted therapies have revolutionized treatment for some cancer types. However, malignancies common in children, thus far, have been less amenable to such targeted therapies. This report describes the clinical course of an 8-year-old female with embryonal RMS having anaplastic features. This patient experienced multiple relapses after receiving various established and experimental therapies. Genomic testing of this RMS subtype revealed mutations in BCOR, ARID1A, and SETD2 genes, each of which contributes to epigenetic regulation and interacts with or modifies the activity of histone deacetylases (HDAC). Based on these findings, the patient was treated with the HDAC inhibitor vorinostat as a single agent. The tumor responded transiently followed by subsequent disease progression. We also examined the efficacy of vorinostat in a patient-derived xenograft (PDX) model developed using tumor tissue obtained from the patient’s most recent tumor resection. The antitumor activity of vorinostat observed with the PDX model reflected clinical observations in that obvious areas of tumor necrosis were evident following exposure to vorinostat. Histologic sections of tumors harvested from PDX tumor-bearing mice treated with vorinostat demonstrated induction of necrosis by this agent. We propose that the evaluation of clinical efficacy in this type of preclinical model merits further evaluation to determine if PDX models predict tumor sensitivity to specific agents and/or combination therapies.

Induction of colon and cervical cancer cell death by cinnamic acid derivatives is mediated through the inhibition of Histone Deacetylases (HDAC)

Recent studies from our group and many others have shown the ability of histone deacetylase (HDAC) inhibitors for retarding the growth of carcinomas of cervix, colon and rectum in vitro. A search for naturally occurring HDAC inhibitors continues due to the adverse effects associated with known HDAC inhibitors like SAHA and TSA. Therefore in the current study, naturally occurring cinnamic acids derivatives were screened for HDAC inhibitory effect using in silico docking method which identified cinnamic acids as potential candidates. Cinnamic acids (CA) are naturally occurring phenolic compounds known to exhibit anticancer properties. However, it is not clearly known whether the anticancer properties of CA derivatives are due to the inhibition of oncogenic HDACs, if so how the efficacy varies among various CA derivatives. Hence, the HDAC inhibitory potential of CA derivatives containing increasing number of hydroxylic groups or methoxy moieties was determined using Discovery Studio software and the most potent CA derivatives tested ex vivo (biochemical assay) as well as in vitro (using cell based assay). Among CA derivatives tested, dihydroxy cinnamic acid (DHCA, commonly known as caffeic acid) exhibited better interactions with HDAC2 (compared to other isoforms) in silico and inhibited its activity ex vivo as well as in vitro. Targeted reduction of HDAC activity using DHCA induced death of cancer cells by (a) generating reactive oxygen species, (b) arresting cells in S and G2/M phases; and (c) induction of caspase-3 mediated apoptosis. In conclusion, we demonstrated that DHCA inhibited cancer cell growth by binding to HDAC followed by the induction of apoptosis.

Novel histone deacetylase inhibitor N25 exerts anti-tumor effects and induces autophagy in human glioma cells by inhibiting HDAC3

N25, a novel histone deacetylase inhibitor, was created through structural modification of suberoylanilide hydroxamic acid. To evaluate the anti-tumor activity of N25 and clarify its molecular mechanism of inducing autophagy in glioma cells, we investigated its in vitro anti-proliferative effect and in vivo anticancer effect. Moreover, we detected whether N25 induces autophagy in glioma cells by transmission electron microscope and analyzed the protein expression level of HDAC3, Tip60, LC3 in glioma samples by western blot. We additionally analyzed the protein expression level of HDAC3, Tip60, ULK1 (Atg1), and Beclin-1 (Atg6) after treatment with N25 in glioma cells. Our results showed that the anti-tumor activity of N25 in glioma cells is slightly stronger than SAHA both in vitro and in vivo. We found that N25 induced autophagy, and HDAC3 was significantly elevated and Tip60 and LC3 significantly decreased in glioma samples compared with normal brain tissues. Nevertheless, N25 inhibited HDAC3 and up-regulated the protein expression of Tip60, ULK1 (Atg1), and Beclin-1 (Atg6) after treatment of glioma cells with N25. In conclusion, these data suggest that N25 has striking anti-tumor activity in part due to inhibition of HDAC3. Additionally, N25 may induce autophagy through inhibiting HDAC3.

Expression and role of nuclear receptor coregulators in colorectal cancer

Colorectal cancer (CRC) is one of the most common human cancers and the cause of about 700000 deaths per year worldwide. Deregulation of the WNT/β-catenin pathway is a key event in CRC initiation. This pathway interacts with other nuclear signaling pathways, including members of the nuclear receptor superfamily and their transcription coregulators. In this review, we provide an overview of the literature dealing with the main coactivators (NCoA-1 to 3, NCoA-6, PGC1-α, p300, CREBBP and MED1) and corepressors (N-CoR1 and 2, NRIP1 and MTA1) of nuclear receptors and summarize their links with the WNT/β-catenin signaling cascade, their expression in CRC and their role in intestinal physiopathology.

Expression of the EP300, TP53 and BAX genes in colorectal cancer: Correlations with clinicopathological parameters and survival

E1A binding protein P300 (EP300), tumor protein P53 (TP53) and BCL2 associated X, apoptosis regulator (BAX) genes encode proteins which cooperate to regulate important cellular processes. The present study aimed to determine the expression levels of EP300, TP53 and BAX in colorectal cancer (CRC) and to investigate their prognostic value and association with the progression of CRC. Tumor and matched unchanged colorectal tissues were collected from 121 CRC patients. Quantitative polymerase chain reaction and immunohistochemistry were used to assess the mRNA and protein levels of the studied genes. Altered expression of the studied genes in CRC tissues was observed at both the mRNA and protein levels. The depth of invasion was associated with TP53 mRNA levels and was correlated negatively with BAX mRNA expression. Moreover, a relationship between tumor location and BAX mRNA content was noted. BAX immunoreactivity was correlated positively with the intensity of p300 immunostaining and was associated with lymph node involvement and tumor-node-metastasis (TNM) disease stage. Univariate regression analysis revealed that overexpression of p53 and BAX in CRC tissues was associated with poor patient outcome. In conclusion, dysregulation of the expression of the studied genes was found to contribute to CRC pathogenesis. The association between p300 and BAX levels suggests the existence of an interdependent regulatory mechanism of their expression. Moreover, BAX expression may be regulated alternatively, in a p53-independent manner, since the lack of correlations between expression of these factors was observed.

5-Fluorouracil targets histone acetyltransferases p300/CBP in the treatment of colorectal cancer

Although 5-fluorouracil (5-FU) is known to interfere with the synthesis of ribonucleic acid and deoxyribonucleic acid, the mechanism underlying its therapeutic efficacy in colorectal cancer (CRC) has not been fully elucidated. We aimed to investigate the influence of 5-FU on histone acetylation, a well-established anti-cancer target, to reveal novel pharmacological effects of 5-FU and their significance for CRC therapy. Results demonstrated that 5-FU induces global histone de-acetylation in multiple CRC cell lines. We identified that 5-FU reduces the binding ability of histone acetyltransferases p300 and CBP to chromatin, and induces their degradation through lysosome. Further work revealed that the degradation of p300/CBP induced by 5-FU was dependent on chaperone-mediated autophagy, mediated by heat-shock cognate protein 70 kDa (hsc70) and lysosomal-associated membrane protein 2A (LAMP2A). Moreover, the degradation of p300/CBP is relevant to cellular resistance to 5-FU, since blocking the degradation enhances 5-FU's cytotoxicity in CRC cells. From clinical data, we demonstrated that low expression of p300/CBP in CRC tissue was closely associated with poor clinical response to 5-FU based-chemotherapy, based on the analysis of 262 colorectal samples from the patients receiving 5-FU treatment: compared to cases with high expression of p300/CBP, those with low expression had lower long-term disease-free survival rate and increased early-progression. These results elucidate a novel pharmacological effect of 5-FU involving global histone de-acetylation by promoting the degradation of p300/CBP, and highlights p300 and CBP as promising predictors of chemo-sensitivity to 5-FU treatment.

Modulating the wnt signaling pathway with small molecules

Wnt signaling is a critical component during embryonic development and also plays an important role in regulating adult tissue homeostasis. Abnormal activation of Wnt signaling has been implicated in many cancers, while reduced activity of Wnt signaling leads to poor wound healing and structural formations. Thus, extensive efforts have been focused on developing small molecules that have potential to either inhibit or activate the pathway, hoping these molecules can offer leads for novel approaches in treating different human diseases. Many small-molecule inhibitors specifically target various elements, such as Frizzled, Disheveled, Porcupine, or Tankyrase, within the Wnt signaling pathways. These small molecules not only have the potential to be further developed as therapeutic reagents, but they may also be used as chemical probes to dissect the underlying mechanism of the Wnt signaling pathways. Therefore, their respective mechanisms and effective dosages are highly pertinent. Aiming to provide an overview of those molecules in a concise, easy-to-use manner, we summarize and organize the current research on them so that it may be helpful for utilization in different studies.

P300 promotes migration, invasion and epithelial-mesenchymal transition in a nasopharyngeal carcinoma cell line

A previous study demonstrated that p300 is overexpressed in nasopharyngeal carcinoma (NPC), and that its expression is an independent prognostic factor. The aim of the present study is to investigate the role of p300 in human NPC development. A small hairpin (sh) RNA lentiviral expression vector targeting the p300 gene was constructed to suppress the expression of p300 in NPC cells. Knockdown of p300 was verified by reverse transcription-quantitative polymerase chain reaction and western blotting. Wound-healing, invasion, immunofluorescence and immunoprecipitation assays were performed to assess the influence of p300 on nasopharyngeal tumorigenesis and metastasis in vitro. The expression of p300 was upregulated in NPC cell lines. After knockdown of p300, the migration and invasion ability of shp300 cells were significantly inhibited (P<0.05). Furthermore, the depletion of p300 expression in NPC cell lines resulted in the upregulation of epithelial phenotype marker E-cadherin and α-catenin, and downregulation of mesenchymal phenotype markers N-cadherin and vimentin. p300 promotes epithelial-mesenchymal transition (EMT) through the acetylation of Smad2 and Smad3 in the tumor growth factor-β signaling pathway. In conclusion, p300 may be involved in the invasion and metastasis of NPC through the induction of EMT.