Dual inhibition of HDAC and tyrosine kinase signaling pathways with CUDC-907 attenuates TGFβ1 induced lung and tumor fibrosis

Epigenetic Regulation of Stromal and Immune Cells and Therapeutic Targets in the Tumor Microenvironment

The tumor microenvironment (TME) plays a pivotal role in neoplastic initiation and progression. Epigenetic machinery, governing the expression of core oncogenes and tumor suppressor genes in transformed cells, significantly contributes to tumor development at both primary and distant sites. Recent studies have illuminated how epigenetic mechanisms integrate external cues and downstream signals, altering the phenotype of stromal cells and immune cells. This remolds the area surrounding tumor cells, ultimately fostering an immunosuppressive microenvironment. Therefore, correcting the TME by targeting the epigenetic modifications holds substantial promise for cancer treatment. This review synthesizes recent research that elucidates the impact of specific epigenetic regulations-ranging from DNA methylation to histone modifications and chromatin remodeling-on stromal and immune cells within the TME. Notably, we highlight their functional roles in either promoting or restricting tumor progression. We also discuss the potential applications of epigenetic agents for cancer treatment, envisaging their ability to normalize the ecosystem. This review aims to assist researchers in understanding the dynamic interplay between epigenetics and the TME, paving the way for better epigenetic therapy.

Histone Deacetylase (HDAC) Inhibitors as a Novel Therapeutic Option Against Fibrotic and Inflammatory Diseases

Histone deacetylases (HDACs) are enzymes that play an essential role in the onset and progression of cancer. As a consequence, a variety of HDAC inhibitors (HDACis) have been developed as potent anticancer agents, several of which have been approved by the FDA for cancer treatment. However, recent accumulated research results have suggested that HDACs are also involved in several other pathophysiological conditions, such as fibrotic, inflammatory, neurodegenerative, and autoimmune diseases. Very recently, the HDAC inhibitor givinostat has been approved by the FDA for an indication beyond cancer: the treatment of Duchenne muscular dystrophy. In recent years, more and more HDACis have been developed as tools to understand the role that HDACs play in various disorders and as a novel therapeutic approach to fight various diseases other than cancer. In the present perspective article, we discuss the development and study of HDACis as anti-fibrotic and anti-inflammatory agents, covering the period from 2020-2024. We envision that the discovery of selective inhibitors targeting specific HDAC isozymes will allow the elucidation of the role of HDACs in various pathological processes and will lead to the development of promising treatments for such diseases.

Targeting Epigenetic Alterations Linked to Cancer-Associated Fibroblast Phenotypes in Lung Cancer

The focus in cancer research and treatment has recently shifted from being primarily tumor-centric to emphasizing the tumor microenvironment (TME) [...].

Single-cell sequencing reveals cellular heterogeneity of nucleus pulposus in intervertebral disc degeneration

The nucleus pulposus (NP) plays a vital role in intervertebral disc degeneration (IVDD). Previous studies have revealed cellular heterogeneity in NP tissue during IVDD progression. However, the cellular and molecular alterations of diverse cell clusters during IVDD remain to be fully elucidated. NP tissues were isolated from patients with different grades of IVDD undergoing discectomy, and then subjected to single-cell RNA sequencing (scRNA-seq). Cell subsets were identified based on unbiased clustering of gene expression profiles. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to determine the molecular features of diverse cell clusters. Monocle analysis was used to illustrate the differentiation trajectories of chondrocytes. Additionally, CellPhoneDB analysis revealed potential interactions between chondrocytes and other cells during IVDD. Based on the expression profiles of 47,610 individual cells, eight putative clusters including chondrocytes, endothelial cells, fibroblasts, macrophages, mural cells, osteoclasts, proliferating stromal cells and T cells were identified. The chondrocyte cluster was classified into three subsets, C1-C3, which were associated with stress-resistance, fibrosis and inflammatory responses, respectively. Pseudo-time trajectories suggested that chondrocytes gradually differentiated into fibroblasts during IVDD. Immune cells including cDC2s, macrophages and monocytes were identified. Further analysis showed that chondrocytes might communicate with immune cells via the MIF, TNFSF9, SPP1 and CCL4L2 signaling pathways. In addition, we found that invading endothelial cells might interact with chondrocytes through the COL4A1, CXCL12, VEGFA and SEMA3E signaling pathways. Our results reveal the cellular complexity and phenotypic characteristics of NP tissues at single-cell resolution, which will contribute to the in-depth investigation of preventative and regenerative strategies for IVDD.

The landscape of histone modification in organ fibrosis

An increase in fibrous connective tissue and a decrease in parenchymal cells in organ tissues are the primary pathological alterations linked to organ fibrosis. If fibrosis is not treated, organ structure is destroyed, function can decline, or even fail, posing a serious risk to human life and health. Numerous organs develop fibrosis, and organ fibroproliferative illnesses account for almost 45% of patient deaths from various diseases in the industrialized world, as well as a major cause of disability and mortality in many other diseases. Recently, it has become evident that histone modification is an important way to regulate gene expression in organ fibrosis. Histone modifications alter the structure of chromatin, thereby affecting gene accessibility. Histone acetylation modifications relax chromatin, making it easier for gene transcription factors to access DNA, thereby promoting gene transcription. In addition, histone modifications recruit other proteins to interact with chromatin to form complexes that further regulate gene expression. Histone methylation modifications recruit methylation-reading proteins that recognize methylation marks and alter gene expression status. It not only affects the normal physiological function of cells, but also plays an important role in organ fibrosis. This article reviews the important role played by histone modifications in organ fibrosis and potential therapeutic approaches.

Histone deacetylases: potential therapeutic targets for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disease of unknown origin and the most common interstitial lung disease. However, therapeutic options for IPF are limited, and novel therapies are urgently needed. Histone deacetylases (HDACs) are enzymes that participate in balancing histone acetylation activity for chromatin remodeling and gene transcription regulation. Increasing evidence suggests that the HDAC family is linked to the development and progression of chronic fibrotic diseases, including IPF. This review aims to summarize available information on HDACs and related inhibitors and their potential applications in treating IPF. In the future, HDACs may serve as novel targets, which can aid in understanding the etiology of PF, and selective inhibition of single HDACs or disruption of HDAC genes may serve as a strategy for treating PF.

CUDC-907 exhibits potent antitumor effects against ovarian cancer through multiple in vivo and in vitro mechanisms

PURPOSE

CUDC-907 is a promising dual-target inhibitor of the HDAC and PI3K signaling pathways, with demonstrated therapeutic effects in a range of malignant tumors. However, its potential application in ovarian cancer (OC) has not been fully explored yet. In this study, we sought to investigate the efficacy of CUDC-907 in treating OC, both in vitro and in vivo.

METHODS

Here, we examined the correlation between PI3K or HDAC expression and the prognosis of OC patients using the GEPIA database. RNA-Seq analysis was performed on OC cells treated with CUDC-907.To assess various cellular processes, including proliferation, migration, invasion, apoptosis, and cell cycle, we performed a series of assays, including the CCK8, EDU, wound healing, cell invasion, and flow cytometry assays. Real-time quantitative PCR and western blotting were performed to measure the expressions of target genes. Additionally, we utilized the SKOV3 xenograft tumor model to investigate the inhibitory effects of CUDC-907 on tumor growth in vivo.

RESULTS

Bioinformatics analyses revealed that up-regulated HDAC and PI3K were significantly correlated with patients' poor survival in OC. In vivo and in vitro experiments have demonstrated that CUDC-907 could inhibit the proliferation of OC cells by inhibiting the PI3K and HDAC pathways to down-regulate the expression of c-Myc, and induce cell apoptosis by inhibiting the PI3K/AKT/Bcl-2 pathway, and up-regulate p21 to induce G2 /M phase arrest.

CONCLUSION

Our results showed that CUDC-907 had powerful anti-tumor effects on OC, which could provide a theoretical and experimental basis for the application of CUDC-907 in the therapy of OC.

Critical Role of histone deacetylase 3 in the regulation of kidney inflammation and fibrosis

Chronic kidney disease (CKD) is characterized by kidney inflammation and fibrosis. However, the precise mechanisms leading to kidney inflammation and fibrosis are poorly understood. Since histone deacetylase is involved in inflammation and fibrosis in other tissues, we examined the role of histone deacetylase 3 (HDAC3) in the regulation of inflammation and kidney fibrosis. HDAC3 is induced in the kidneys of animal models of CKD but mice with conditional HDAC3 deletion exhibit significantly reduced fibrosis in the kidneys compared with control mice. The expression of proinflammatory and profibrotic genes was significantly increased in the fibrotic kidneys of control mice, which was impaired in mice with HDAC3 deletion. Genetic deletion or pharmacological inhibition of HDAC3 reduced the expression of proinflammatory genes in cultured monocytes/macrophages. Mechanistically, HDAC3 deacetylates Lys122 of NF-κB p65 subunit turning on transcription. RGFP966, a selective HDAC3 inhibitor, reduced fibrosis in cells and in animal models by blocking NF-κB p65 binding to κB-containing DNA sequences. Thus, our study identified HDAC3 as a critical regulator of inflammation and fibrosis of the kidney through deacetylation of NF-κB unlocking its transcriptional activity. Hence, targeting HDAC3 could serve as a novel therapeutic strategy for CKD.

Boosting immune responses in lung tumor immune microenvironment: A comprehensive review of strategies and adjuvants

The immune system has a substantial impact on the growth and expansion of lung malignancies. Immune cells are encompassed by a stroma comprising an extracellular matrix (ECM) and different cells like stromal cells, which are known as the tumor immune microenvironment (TIME). TME is marked by the presence of immunosuppressive factors, which inhibit the function of immune cells and expand tumor growth. In recent years, numerous strategies and adjuvants have been developed to extend immune responses in the TIME, to improve the efficacy of immunotherapy. In this comprehensive review, we outline the present knowledge of immune evasion mechanisms in lung TIME, explain the biology of immune cells and diverse effectors on these components, and discuss various approaches for overcoming suppressive barriers. We highlight the potential of novel adjuvants, including toll-like receptor (TLR) agonists, cytokines, phytochemicals, nanocarriers, and oncolytic viruses, for enhancing immune responses in the TME. Ultimately, we provide a summary of ongoing clinical trials investigating these strategies and adjuvants in lung cancer patients. This review also provides a broad overview of the current state-of-the-art in boosting immune responses in the TIME and highlights the potential of these approaches for improving outcomes in lung cancer patients.

Zinc-Dependent Histone Deacetylases in Lung Endothelial Pathobiology

A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and, as such, provides a semi-selective barrier between the blood and the interstitial space. Compromise of the lung EC barrier due to inflammatory or toxic events may result in pulmonary edema, which is a cardinal feature of acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS). The EC functions are controlled, at least in part, via epigenetic mechanisms mediated by histone deacetylases (HDACs). Zinc-dependent HDACs represent the largest group of HDACs and are activated by Zn2+. Members of this HDAC group are involved in epigenetic regulation primarily by modifying the structure of chromatin upon removal of acetyl groups from histones. In addition, they can deacetylate many non-histone histone proteins, including those located in extranuclear compartments. Recently, the therapeutic potential of inhibiting zinc-dependent HDACs for EC barrier preservation has gained momentum. However, the role of specific HDAC subtypes in EC barrier regulation remains largely unknown. This review aims to provide an update on the role of zinc-dependent HDACs in endothelial dysfunction and its related diseases. We will broadly focus on biological contributions, signaling pathways and transcriptional roles of HDACs in endothelial pathobiology associated mainly with lung diseases, and we will discuss the potential of their inhibitors for lung injury prevention.

Hydroxamic acid hybrids: Histone deacetylase inhibitors with anticancer therapeutic potency

Histone deacetylases (HDACs), a class of enzymes responsible for the removal of acetyl functional groups from the lysine residues in the amino-terminal tails of core histones, play a critical role in the modulation of chromatin architecture and the regulation of gene expression. Dysregulation of HDAC expression has been closely associated with the development of various cancers. Histone deacetylase inhibitors (HDACis) could regulate diverse cellular pathways, cause cell cycle arrest, and promote programmed cell death, making them promising avenues for cancer therapy with potent efficacy and favorable toxicity profiles. Hybrid molecules incorporating two or more pharmacophores in one single molecule, have the potential to simultaneously inhibit two distinct cancer targets, potentially overcome drug resistance and minimize drug-drug interactions. Notably, hydroxamic acid hybrids, exemplified by fimepinostat and tinostamustine as potential HDACis, could exert the anticancer effects through induction of apoptosis, differentiation, and growth arrest in cancer cells, representing useful scaffolds for the discovery of novel HDACis. The purpose of this review is to summarize the current scenario of hydroxamic acid hybrids as HDACis with anticancer therapeutic potential developed since 2020 to facilitate further rational exploitation of more effective candidates.

Integrated molecular modeling and dynamics approaches revealed the mechanism of selective inhibition of HDAC6/8

The high structural homology of histone deacetylases 6 and 8 (HDAC6/8) poses a challenge in achieving isoform selectivity and has resulted in adverse side effects due to pan-inhibition in clinical applications. Additionally, the rational design of dual-target inhibitors, centered on HDAC6/8, demands a profound understanding of their selectivity mechanisms. Addressing the urgent need for enhanced specificity in the development of inhibitors targeting specific isoforms, we elucidate the mechanism underpinning the selective inhibition of HDAC6/8 inhibitors through in-silico strategies. The hydrogen bonding interaction with Asp101 and Tyr306 is a key factor that enables compound 12b to selectively inhibit HDAC8. Its favorable spatial orientation places the Cap group of 12b between Tyr306 and Tyr100, resulting in an overall L-shaped conformation. These two factors significantly contribute to the selective inhibitory activity of 12b against HDAC8. The zinc binding group (ZBG) of compound NN-390 forms a hydrogen bond with His610, a key residue of HDAC6, facilitating stable chelation with zinc ions. In addition, the Cap group of NN-390 interacts with Phe620 and Phe680 via van der Waals forces, leading to an overall Y-shaped conformation. The aforementioned factors are the main reasons for the selective inhibition of HDAC6 by NN-390. Furthermore, whether the Cap group is in the para or meta-position will influence the selective inhibition of either HDAC6 or HDAC8. We believe these clues can offer valuable insights for the rational design of selective inhibitors targeting HDAC6/8 and pave the way for rational design of dual-target HDAC6/8-based inhibitors.Communicated by Ramaswamy H. Sarma.

New aspects of the epigenetic regulation of EMT related to pulmonary fibrosis

Pulmonary fibrosis is a chronic and progressive fibrotic disease that results in impaired gas exchange, ventilation, and eventual death. The pro-fibrotic environment is instigated by various factors, leading to the transformation of epithelial cells into myofibroblasts and/or fibroblasts that trigger fibrosis. Epithelial mesenchymal transition (EMT) is a biological process that plays a critical role in the pathogenesis of pulmonary fibrosis. Epigenetic regulation of tissue-stromal crosstalk involving DNA methylation, histone modifications, non-coding RNA, and chromatin remodeling plays a key role in the control of EMT. The review investigates the epigenetic regulation of EMT and its significance in pulmonary fibrosis.

Synergistic Power of Piceatannol and/or Vitamin D in Bleomycin-Induced Pulmonary Fibrosis In Vivo: A Preliminary Study

Oxidative stress and epigenetic alterations, including the overexpression of all class I and II histone deacetylases (HDACs), particularly HDAC2 and HDAC4, have been identified as key molecular mechanisms driving pulmonary fibrosis. Treatment with piceatannol (PIC) or vitamin D (Vit D) has previously exhibited mitigating impacts in pulmonary fibrosis models. The present study investigated the effects of PIC, Vit D, or a combination (PIC-Vit D) on the expression of HDAC2, HDAC4, and transforming growth factor-beta (TGF-β) in the lungs; the phosphatidylinositide-3-kinase (PI3K)/AKT signaling pathway; and the antioxidant status of the lungs. The objective was to determine if the treatments had protective mechanisms against pulmonary fibrosis caused by bleomycin (BLM) in rats. Adult male albino rats were given a single intratracheal dosage of BLM (10 mg/kg) to induce pulmonary fibrosis. PIC (15 mg/kg/day, oral (p.o.)), Vit D (0.5 μg/kg/day, intraperitoneal (i.p.)), or PIC-Vit D (15 mg/kg/day, p.o. plus 0.5 μg/kg/day, i.p.) were given the day following BLM instillation and maintained for 14 days. The results showed that PIC, Vit D, and PIC-Vit D significantly improved the histopathological sections; downregulated the expression of HDAC2, HDAC4, and TGF-β in the lungs; inhibited the PI3K/AKT signaling pathway; decreased extracellular matrix (ECM) deposition including collagen type I and alpha smooth muscle actin (α-SMA); and increased the antioxidant capacity of the lungs by increasing the levels of glutathione (GSH) that had been reduced and decreasing the levels of malondialdehyde (MDA) compared with the BLM group at a p-value less than 0.05. The concomitant administration of PIC and Vit D had a synergistic impact that was greater than the impact of monotherapy with either PIC or Vit D. PIC, Vit D, and PIC-Vit D exhibited a notable protective effect through their antioxidant effects, modulation of the expression of HDAC2, HDAC4, and TGF-β in the lungs, and suppression of the PI3K/AKT signaling pathway.

Discovery of HDAC6, HDAC8, and 6/8 Inhibitors and Development of Cell-Based Drug Screening Models for the Treatment of TGF-β-Induced Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is incurable, and its progression is difficult to control and thus can lead to pulmonary deterioration. Pan-histone deacetylase inhibitors such as SAHA have shown potential for modulating pulmonary fibrosis yet with off-target effects. Therefore, selective HDAC inhibitors would be beneficial for reducing side effects. Toward this goal, we designed and synthesized 24 novel HDAC6, HDAC8, or dual HDAC6/8 inhibitors and established a two-stage screening platform to rapidly screen for HDAC inhibitors that effectively mitigate TGF-β-induced pulmonary fibrosis. The first stage consisted of a mouse NIH-3T3 fibroblast prescreen and yielded five hits. In the second stage, human pulmonary fibroblasts (HPFs) were used, and four out of the five hits were tested for caco-2 permeability and liver microsome stability to give two potential leads: J27644 (15) and 20. This novel two-stage screen platform will accelerate the discovery and reduce the cost of developing HDAC inhibitors to mitigate TGF-β-induced pulmonary fibrosis.

Epigenetic regulation and therapeutic targets in the tumor microenvironment

The tumor microenvironment (TME) is crucial to neoplastic processes, fostering proliferation, angiogenesis and metastasis. Epigenetic regulations, primarily including DNA and RNA methylation, histone modification and non-coding RNA, have been generally recognized as an essential feature of tumor malignancy, exceedingly contributing to the dysregulation of the core gene expression in neoplastic cells, bringing about the evasion of immunosurveillance by influencing the immune cells in TME. Recently, compelling evidence have highlighted that clinical therapeutic approaches based on epigenetic machinery modulate carcinogenesis through targeting TME components, including normalizing cells' phenotype, suppressing cells' neovascularization and repressing the immunosuppressive components in TME. Therefore, TME components have been nominated as a promising target for epigenetic drugs in clinical cancer management. This review focuses on the mechanisms of epigenetic modifications occurring to the pivotal TME components including the stroma, immune and myeloid cells in various tumors reported in the last five years, concludes the tight correlation between TME reprogramming and tumor progression and immunosuppression, summarizes the current advances in cancer clinical treatments and potential therapeutic targets with reference to epigenetic drugs. Finally, we summarize some of the restrictions in the field of cancer research at the moment, further discuss several interesting epigenetic gene targets with potential strategies to boost antitumor immunity.

Chidamide, a novel histone deacetylase inhibitor, inhibits laryngeal cancer progression in vitro and in vivo

Although surgery is an important treatment for laryngeal cancer, surgery has a significant negative impact on the quality of life of patients, and many patients have poor tolerance to surgery. Therefore, alternative chemotherapeutic drugs are an important research hotspot. Chidamide is a histone deacetylase inhibitor that selectively inhibits the expression of type I and IIb histone deacetylases (1, 2, 3 and 10). It has a significant anticancer effect on a variety of solid tumours. This study verified the inhibitory effect of chidamide on laryngeal carcinoma. We conducted a variety of cellular and animal experiments to explore how chidamide inhibits the development of laryngeal cancer. The results showed that chidamide had significant antitumour activity against laryngeal carcinoma cells and xenografts and could induce cell apoptosis, ferroptosis and pyroptosis. This study provides a potential option for the treatment of laryngeal cancer.

Therapeutic Targeting of Cancer-Associated Fibroblasts in the Non-Small Cell Lung Cancer Tumor Microenvironment

Lung cancer is the most frequently diagnosed cancer and the leading cause of cancer death worldwide. The most common lung cancer is non-small cell lung cancer (NSCLC), with an overall 5-year survival rate of around 20% because NSCLC is a metastatic disease. A better understanding of the mechanism underlying lung cancer metastasis is therefore urgently needed. The tumor microenvironment involves different types of stromal cells and functions as key components in the progression of NSCLC. Through epithelial-mesenchymal transition (EMT), in which epithelial cells lose their polarity and acquire mesenchymal potential, cancer cells acquire metastatic abilities, as well as cancer stem-cell-like potential. We previously reported that cancer-associated fibroblasts (CAFs) interact with lung cancer cells to allow for the acquisition of malignancy and treatment resistance by paracrine loops via EMT signals in the tumor microenvironment. Furthermore, CAFs regulate the cytotoxic activity of immune cells via various cytokines and chemokines, creating a microenvironment of immune tolerance. Regulation of CAFs can therefore affect immune responses. Recent research has shown several roles of CAFs in NSCLC tumorigenesis, owing to their heterogeneity, so molecular markers of CAFs should be elucidated to better classify tumor-promoting subtypes and facilitate the establishment of CAF-specific targeted therapies. CAF-targeted cancer treatments may suppress EMT and regulate the niche of cancer stem cells and the immunosuppressive network and thus may prove useful for NSCLC treatment through multiple mechanisms.

Signaling pathways in cancer-associated fibroblasts: recent advances and future perspectives

As a critical component of the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) play important roles in cancer initiation and progression. Well-known signaling pathways, including the transforming growth factor-β (TGF-β), Hedgehog (Hh), Notch, Wnt, Hippo, nuclear factor kappa-B (NF-κB), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), mitogen-activated protein kinase (MAPK), and phosphoinositide 3-kinase (PI3K)/AKT pathways, as well as transcription factors, including hypoxia-inducible factor (HIF), heat shock transcription factor 1 (HSF1), P53, Snail, and Twist, constitute complex regulatory networks in the TME to modulate the formation, activation, heterogeneity, metabolic characteristics and malignant phenotype of CAFs. Activated CAFs remodel the TME and influence the malignant biological processes of cancer cells by altering the transcriptional and secretory characteristics, and this modulation partially depends on the regulation of signaling cascades. The results of preclinical and clinical trials indicated that therapies targeting signaling pathways in CAFs demonstrated promising efficacy but were also accompanied by some failures (e.g., NCT01130142 and NCT01064622). Hence, a comprehensive understanding of the signaling cascades in CAFs might help us better understand the roles of CAFs and the TME in cancer progression and may facilitate the development of more efficient and safer stroma-targeted cancer therapies. Here, we review recent advances in studies of signaling pathways in CAFs and briefly discuss some future perspectives on CAF research.

Microbiome dysbiosis and epigenetic modulations in lung cancer: From pathogenesis to therapy

The lung microbiome plays an essential role in maintaining healthy lung function, including host immune homeostasis. Lung microbial dysbiosis or disruption of the gut-lung axis can contribute to lung carcinogenesis by causing DNA damage, inducing genomic instability, or altering the host's susceptibility to carcinogenic insults. Thus far, most studies have reported the association of microbial composition in lung cancer. Mechanistic studies describing host-microbe interactions in promoting lung carcinogenesis are limited. Considering cancer as a multifaceted disease where epigenetic dysregulation plays a critical role, epigenetic modifying potentials of microbial metabolites and toxins and their roles in lung tumorigenesis are not well studied. The current review explains microbial dysbiosis and epigenetic aberrations in lung cancer and potential therapeutic opportunities.

Anti-tumor effects of dual PI3K-HDAC inhibitor CUDC-907 on activation of ROS-IRE1α-JNK-mediated cytotoxic autophagy in esophageal cancer

Background

PI3K-Akt pathway activation and the expression of histone deacetylases (HDACs) are highly increased in esophageal cancer, suggesting that inhibition of such targets may be a viable therapeutic strategy. Herein, we aimed to evaluate the anti-tumor effect of CUDC-907, a dual PI3K-HDAC inhibitor, in esophageal squamous cell carcinoma (ESCC).

Methods

The anti-tumor effects of CUDC-907 in ESCC were evaluated using cell counting kit-8, flow cytometry, and western blot. mRNA-sequencing was used to explore the mechanism underlying CUDC-907 anti-tumor effects. The relations of reactive oxygen species (ROS), lipocalin 2 (LCN2), and CUDC-907 were determined by flow cytometry, rescue experiments, and western blot. The activation of the IRE1α-JNK-CHOP signal cascade was confirmed by western blot. The in vivo inhibitory effects of CUDC-907 were examined by a subcutaneous xenograft model in nude mice.

Results

CUDC-907 displayed effective inhibition in the proliferation, migration, and invasion of ESCC cells. Through an mRNA-sequencing and functional enrichment analysis, autophagy was found to be associated with cancer cells death. CUDC-907 not only inhibited the PI3K-Akt-mTOR pathways to result in autophagy, but also induced ROS accumulation to activate IRE1α-JNK-CHOP-mediated cytotoxic autophagy by downregulating LCN2 expression. Consistently, the in vivo anti-tumor effects of CUDC-907 accompanied by the downregulated expression of p-mTOR and LCN2 and upregulated expression of p-IRE1α and LC3B-II were evaluated in a xenograft mouse model.

Conclusion

Our findings suggested the clinical development and administration of CUDC-907 might act as a novel treatment strategy for ESCC. A more in-depth understanding of the anti-tumor effect of CUDC-907 in ESCC will benefit the clinically targeted treatment of ESCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00855-x.

Specific epigenetic regulators serve as potential therapeutic targets in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF), a disorder observed mostly in older human beings, is characterised by chronic and progressive lung scarring leading to an irreversible decline in lung function. This health condition has a dismal prognosis and the currently available drugs only delay but fail to reverse the progression of lung damage. Consequently, it becomes imperative to discover improved therapeutic compounds and their cellular targets to cure IPF. In this regard, a number of recent studies have targeted the epigenetic regulation by histone deacetylases (HDACs) to develop and categorise antifibrotic drugs for lungs. Therefore, this review focuses on how aberrant expression or activity of Classes I, II and III HDACs alter TGF-β signalling to promote events such as epithelial-mesenchymal transition, differentiation of activated fibroblasts into myofibroblasts, and excess deposition of the extracellular matrix to propel lung fibrosis. Further, this study describes how certain chemical compounds or dietary changes modulate dysregulated HDACs to attenuate five faulty TGF-β-dependent profibrotic processes, both in animal models and cell lines replicating IPF, thereby identifying promising means to treat this lung disorder.

Dual Targeting of PI3K and HDAC by CUDC-907 Inhibits Pediatric Neuroblastoma Growth

Simple Summary

High-risk neuroblastoma (NB) is an aggressive cancer of very young children and accounts for almost 15% of all pediatric cancer deaths. Current therapies include high-dose chemotherapy and radiation, which have long-term toxic side effects. Despite these intensive therapies, the overall 5-year survival rate of NB is less than 50%. Therefore, developing novel therapeutic approaches targeting the molecular mechanisms that drive NB progression is very important. In the present study, we repurpose CUDC-907, a dual inhibitor of PI3K and histone deacetylases. These regulators are known to regulate MYCN expression, a key prognostic marker of NB. CUDC-907 potently inhibits NB growth and 3D spheroid tumor growth by inhibiting PI3K, HDAC, and MYCN. Overall, our pre-clinical data demonstrate that repurposing CUDC-907 as a single drug is a novel and effective therapeutic approach for NB.

Abstract

The dysregulation of PI3K, HDACs, and MYCN are well known for promoting multiple cancer types, including neuroblastoma (NB). Targeting the upstream regulators of MYCN, including HDACs and PI3K, was shown to suppress cancer growth. In the present study, we analyze different NB patient datasets to reveal that high PI3K and HDAC expression is correlated with overall poor NB patient survival. High PI3K level is also found to be associated with high MYCN level and NB stage progression. We repurpose a dual inhibitor CUDC-907 as a single agent to directly target both PI3K and HDAC in NB. We use in vitro methodologies to determine the efficacy and selectivity of CUDC-907 using six NB and three control fibroblast cell lines. Our results show that CUDC-907 significantly inhibits NB proliferation and colony growth, induces apoptosis, blocks cell cycle progression, inhibits MYCN, and enhances H3K9Ac levels by inhibiting the PI3K/AKT signaling pathway and HDAC function. Furthermore, CUDC-907 significantly inhibits NB tumor growth in a 3D spheroid tumor model that recapitulates the in vivo tumor growth. Overall, our findings highlight that the dual inhibition of PI3K and HDAC by CUDC-907 is an effective therapeutic strategy for NB and other MYC-dependent cancers.

The Cross-Talk between Epigenetic Gene Regulation and Signaling Pathways Regulates Cancer Pathogenesis

Cancer begins due to uncontrolled cell division. Cancer cells are insensitive to the signals that control normal cell proliferation. This uncontrolled cell division is due to the accumulation of abnormalities in different factors associated with the cell division, including different cyclins, cell cycle checkpoint inhibitors, and cellular signaling. Cellular signaling pathways are aberrantly activated in cancer mainly due to epigenetic regulation and post-translational regulation. In this chapter, the role of epigenetic regulation in aberrant activation of PI3K/AKT, Ras, Wnt, Hedgehog, Notch, JAK/STAT, and mTOR signaling pathways in cancer progression is discussed. The role of epigenetic regulators in controlling the upstream regulatory proteins and downstream effector proteins responsible for abnormal cellular signaling-mediated cancer progression is covered in this chapter. Similarly, the role of signaling pathways in controlling epigenetic gene regulation-mediated cancer progression is also discussed. We have tried to ascertain the current status of potential epigenetic drugs targeting several epigenetic regulators to prevent different cancers.

Histone deacetylases: A novel class of therapeutic targets for pancreatic cancer

Pancreatic cancer is the seventh leading cause of cancer death worldwide, with a low 5-year survival rate. Novel agents are urgently necessary to treat the main pathological type, known as pancreatic ductal carcinoma (PDAC). The dysregulation of histone deacetylases (HDACs) has been identified in association with PDAC, which can be more easily targeted by small molecular inhibitors than gene mutations and may represent a therapeutic breakthrough for PDAC. However, the contributions of HDACs to PDAC remain controversial, and pharmacokinetic challenges have limited the application of HDAC inhibitors (HDACis) in PDAC. This review summarizes the mechanisms associated with success and failure of HDACis in PDAC and discusses the recent progress made in HDACi development and application, such as combination therapies designed to enhance efficacy. More precise strategies involving HDACis might eventually improve the outcomes of PDAC treatment.

Therapeutic and diagnostic targeting of fibrosis in metabolic, proliferative and viral disorders

Fibrosis is a common denominator in many pathologies and crucially affects disease progression, drug delivery efficiency and therapy outcome. We here summarize therapeutic and diagnostic strategies for fibrosis targeting in atherosclerosis and cardiac disease, cancer, diabetes, liver diseases and viral infections. We address various anti-fibrotic targets, ranging from cells and genes to metabolites and proteins, primarily focusing on fibrosis-promoting features that are conserved among the different diseases. We discuss how anti-fibrotic therapies have progressed over the years, and how nanomedicine formulations can potentiate anti-fibrotic treatment efficacy. From a diagnostic point of view, we discuss how medical imaging can be employed to facilitate the diagnosis, staging and treatment monitoring of fibrotic disorders. Altogether, this comprehensive overview serves as a basis for developing individualized and improved treatment strategies for patients suffering from fibrosis-associated pathologies.

Fibrosis: Sirtuins at the checkpoints of myofibroblast differentiation and profibrotic activity

Fibrotic diseases are still a serious concern for public health, due to their high prevalence, complex etiology and lack of successful treatments. Fibrosis consists of excessive accumulation of extracellular matrix components. As a result, the structure and function of tissues are impaired, thus potentially leading to organ failure and death in several chronic diseases. Myofibroblasts represent the principal cellular mediators of fibrosis, due to their extracellular matrix producing activity, and originate from different types of precursor cells, such as mesenchymal cells, epithelial cells and fibroblasts. Profibrotic activation of myofibroblasts can be triggered by a variety of mechanisms, including the transforming growth factor-β signalling pathway, which is a major factor driving fibrosis. Interestingly, preclinical and clinical studies showed that fibrotic degeneration can stop and even reverse by using specific antifibrotic treatments. Increasing scientific evidence is being accumulated about the role of sirtuins in modulating the molecular pathways responsible for the onset and development of fibrotic diseases. Sirtuins are NAD⁺ -dependent protein deacetylases that play a crucial role in several molecular pathways within the cells, many of which at the crossroad between health and disease. In this context, we will report the current knowledge supporting the role of sirtuins in the balance between healthy and diseased myofibroblast activity. In particular, we will address the signalling pathways and the molecular targets that trigger the differentiation and profibrotic activation of myofibroblasts and can be modulated by sirtuins.