HDAC inhibitors in models of inflammation-related tumorigenesis

The Histone Deacetylase Family: Structural Features and Application of Combined Computational Methods

Histone deacetylases (HDACs) are crucial in gene transcription, removing acetyl groups from histones. They also influence the deacetylation of non-histone proteins, contributing to the regulation of various biological processes. Thus, HDACs play pivotal roles in various diseases, including cancer, neurodegenerative disorders, and inflammatory conditions, highlighting their potential as therapeutic targets. This paper reviews the structure and function of the four classes of human HDACs. While four HDAC inhibitors are currently available for treating hematological malignancies, numerous others are undergoing clinical trials. However, their non-selective toxicity necessitates ongoing research into safer and more efficient class-selective or isoform-selective inhibitors. Computational methods have aided the discovery of HDAC inhibitors with the desired potency and/or selectivity. These methods include ligand-based approaches, such as scaffold hopping, pharmacophore modeling, three-dimensional quantitative structure-activity relationships, and structure-based virtual screening (molecular docking). Moreover, recent developments in the field of molecular dynamics simulations, combined with Poisson-Boltzmann/molecular mechanics generalized Born surface area techniques, have improved the prediction of ligand binding affinity. In this review, we delve into the ways in which these methods have contributed to designing and identifying HDAC inhibitors.

Dysregulation of histone deacetylases in ocular diseases

Ocular diseases are a growing global concern and have a significant impact on the quality of life. Cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy are the most prevalent ocular diseases. Their prevalence and the global market size are also increasing. However, the available pharmacotherapy is currently limited. These diseases share common pathophysiological features, including neovascularization, inflammation, and/or neurodegeneration. Histone deacetylases (HDACs) are a class of enzymes that catalyze the removal of acetyl groups from lysine residues of histone and nonhistone proteins. HDACs are crucial for regulating various cellular processes, such as gene expression, protein stability, localization, and function. They have also been studied in various research fields, including cancer, inflammatory diseases, neurological disorders, and vascular diseases. Our study aimed to investigate the relationship between HDACs and ocular diseases, to identify a new strategy for pharmacotherapy. This review article explores the role of HDACs in ocular diseases, specifically focusing on diabetic retinopathy, age-related macular degeneration, and retinopathy of prematurity, as well as optic nerve disorders, such as glaucoma and optic neuropathy. Additionally, we explore the interplay between HDACs and key regulators of fibrosis and angiogenesis, such as TGF-β and VEGF, highlighting the potential of targeting HDAC as novel therapeutic strategies for ocular diseases.

The roles of HDAC with IMPDH and mTOR with JAK as future targets in the treatment of rheumatoid arthritis with combination therapy

Various studies have shown that cytokines are important regulators in rheumatoid arthritis (RA). In synovial inflammation alteration of the enzyme HDAC, IMPDH enzyme, mTOR pathway, and JAK pathway increase cytokine level. These increased cytokine levels are responsible for the inflammation in RA. Inflammation is a physiological and normal reaction of the immune system against dangerous stimuli such as injury and infection. The cytokine-based approach improves the treatment of RA. To reach this goal, various researchers and scientists are working more aggressively by using a combination approach. The present review of combination therapy provides essential evidence about the possible synergistic effect of combinatorial agents. We have focused on the effects of HDAC inhibitor with IMPDH inhibitor and mTOR inhibitor with JAK inhibitor in combination for the treatment of RA. Combining various targeted strategies can be helpful for the treatment of RA.

Lansoprazole as a potent HDAC2 inhibitor for treatment of colorectal cancer: An in-silico analysis and experimental validation

BACKGROUND

Histone deacetylase 2 (HDAC2), belonging to the class I HDAC family, holds significant therapeutic potential as a crucial target for diverse cancer types. As key players in the realm of epigenetic regulatory enzymes, histone deacetylases (HDACs) are intricately involved in the onset and progression of cancer. Consequently, pursuing isoform-specific inhibitors targeting histone deacetylases (HDACs) has garnered substantial interest in both biological and medical circles. The objective of the present investigation was to employ a drug repurposing approach to discover novel and potent HDAC2 inhibitors.

MATERIALS AND METHODS

In this study, our protocol is presented on virtual screening to identify novel potential HDAC2 inhibitors through 3D-QSAR, molecular docking, pharmacophore modeling, and molecular dynamics (MD) simulation. Afterward, In-vitro assays were employed to evaluate the cytotoxicity, apoptosis, and migration of HCT-116 cell lines under treatment of hit compound and valproic acid as a control inhibitor. The expression levels of HDAC2, TP53, BCL2, and BAX were evaluated by QRT-PCR.

RESULTS

RMSD, RMSF, H-bond, and DSSP analysis results confirmed that among bioinformatically selected compounds, lansoprazole exhibited the highest HDAC2 inhibitory potential. Experimental validation revealed that lansoprazole displayed significant antiproliferative activity. The determined IC50 value was 400 ± 2.36 μM. Furthermore, the apoptotic cells ratio concentration-dependently increased under Lansoprazole treatment. Results of the Scratch assay indicated that lansoprazole led to decreasing the migration of CRC cells. Finally, under Lansoprazole treatment the expression level of BCL2 and HDAC2 decreased and BAX and TP53 increased.

CONCLUSION

Taking together the results of the current study indicated that Lansoprazole as a novel HDAC2 inhibitor, could be used as a potential therapeutic agent for the treatment of CRC. Although, further experimental studies should be performed before using this compound in the clinic.

Deciphering the Mysterious Relationship between the Cross-Pathogenetic Mechanisms of Neurodegenerative and Oncological Diseases

The relationship between oncological pathologies and neurodegenerative disorders is extremely complex and is a topic of concern among a growing number of researchers around the world. In recent years, convincing scientific evidence has accumulated that indicates the contribution of a number of etiological factors and pathophysiological processes to the pathogenesis of these two fundamentally different diseases, thus demonstrating an intriguing relationship between oncology and neurodegeneration. In this review, we establish the general links between three intersecting aspects of oncological pathologies and neurodegenerative disorders, i.e., oxidative stress, epigenetic dysregulation, and metabolic dysfunction, examining each process in detail to establish an unusual epidemiological relationship. We also focus on reviewing the current trends in the research and the clinical application of the most promising chemical structures and therapeutic platforms that have a modulating effect on the above processes. Thus, our comprehensive analysis of the set of molecular determinants that have obvious cross-functional pathways in the pathogenesis of oncological and neurodegenerative diseases can help in the creation of advanced diagnostic tools and in the development of innovative pharmacological strategies.

Discovery of New Uracil and Thiouracil Derivatives as Potential HDAC Inhibitors

Background: Histone deacetylase inhibitors (HDACIs) are a relatively new class of potential drugs for treating cancer. Aim: Discovery of new anticancer agents targeting HDAC. Methods: New uracil and thiouracil derivatives panels were designed and synthesized as HDAC inhibitors. The synthesized compounds were tested against MCF-7, HepG2, and HCT-116. HDAC1 and HDAC4 inhibitory activities of these compounds were tested. The most active member was tested for its potential against cell cycle, apoptosis, caspase-3, and caspase-8. Docking studies were carried out against HDAC1. Results: Compounds 5a, 5b, 5f, 5i, 5k, and 5m exhibited promising cytotoxic activities. HDAC1 and HDAC4 inhibitory activities of these compounds were tested. Regarding the HDAC1 inhibitory activity, compound 5m was the most potent member (IC₅₀ = 0.05 µg/mL) compared to trichostatin A (IC₅₀ = 0.0349 µg/mL). For HDAC4, compound 5m showed superior activity (IC₅₀ = 2.83 µg/mL) than trichostatin A (IC₅₀ = 3.349 µg/mL). Compound 5m showed a high potential to arrest the HCT116 cell cycle at the G0-G1 phase. In addition, it showed an almost 17 times apoptotic effect (37.59%) compared to the control cells (2.17%). Furthermore, Compound 5m showed significant increases in the levels of caspase-3 and caspase-8. Finally, the uracil and thiouracil derivatives showed accepted binding mods against HDAC. Conclusions: Compound 5m has potential anticancer activity targeting HDAC with a significant apoptotic effect.

Protective Effect of Clostridium butyricum on Escherichia coli-Induced Endometritis in Mice via Ameliorating Endometrial Barrier and Inhibiting Inflammatory Response

Endometritis is a common reproductive disease occurs both in human and animals. Clostridium butyricum is a Gram-positive anaerobic bacterium that can ferment various carbohydrates into butyric acid. In this study, we investigated the effects of C. butyricum on Escherichia coli-induced endometritis and clarified the underlying mechanism. We first verified the protective effect of C. butyricum in vivo by establishing a mouse model of E. coli-induced endometritis. It was determined that C. butyricum pretreatment significantly reversed E. coli-induced uterine histopathological changes. Meanwhile, C. butyricum pretreatment significantly decreased the production of pro-inflammatory mediators and the levels of myeloperoxidase (MPO) and malondialdehyde (MDA). We found that C. butyricum could inhibit TLR4-mediated phosphorylation of NF-κB and the activity of histone deacetylase (HDAC). Furthermore, C. butyricum significantly increased the expression of the tight junction proteins (TJPs) ZO-1, claudin-3, and occludin. Additionally, treatment with C. butyricum culture supernatant dramatically suppressed the degree of inflammation in the uterus, and inactivated C. butyricum did not exert a protective effect. We subsequently investigated butyrate levels in both the uterus and blood and observed a marked augment in the C. butyricum treatment group. Collectively, our data suggest that C. butyricum maintains epithelial barrier function and suppresses inflammatory response during E. coli-induced endometritis and that the protective effect of C. butyricum may be related to the production of butyrate. IMPORTANCE Endometritis is a common reproductive disease both in human and animals. It impairs female fertility by disrupting endometrial function. Antibiotics are widely used to treat endometritis in clinical practice, but the misuse of antibiotics often leads to antibiotic resistance. Therefore, there is an urgent need for new therapeutic agents to treat bacterial endometritis and overcome bacterial resistance. In this study, we found that C. butyricum could protect from E. coli-induced endometritis.

Vaginal Nanoformulations for the Management of Preterm Birth

Preterm birth (PTB) is a leading cause of infant morbidity and mortality in the world. In 2020, 1 in 10 infants were born prematurely in the United States. The World Health Organization estimates that a total of 15 million infants are born prematurely every year. Current therapeutic interventions for PTB have had limited replicable success. Recent advancements in the field of nanomedicine have made it possible to utilize the vaginal administration route to effectively and locally deliver drugs to the female reproductive tract. Additionally, studies using murine models have provided important insights about the cervix as a gatekeeper for pregnancy and parturition. With these recent developments, the field of reproductive biology is on the cusp of a paradigm shift in the context of treating PTB. The present review focuses on the complexities associated with treating the condition and novel therapeutics that have produced promising results in preclinical studies.

Metformin and histone deacetylase inhibitor based anti-inflammatory nanoplatform for epithelial-mesenchymal transition suppression and metastatic tumor treatment

Epithelial-mesenchymal transition (EMT), a differentiation process with aberrant changes of tumor cells, is identified as an initial and vital procedure for metastatic processes. Inflammation is a significant inducer of EMT and provides an indispensable target for blocking EMT, however, an anti-inflammatory therapeutic with highlighted safety and efficacy is deficient. Metformin is a promising anti-inflammatory agent with low side effects, but tumor monotherapy with an anti-inflammation drug could generate therapy resistance, cell adaptation or even promote tumor development. Combination therapies with various anti-inflammatory mechanisms can be favorable options improving therapeutic effects of metformin, here we develop a tumor targeting hybrid micelle based on metformin and a histone deacetylase inhibitor propofol-docosahexaenoic acid for efficient therapeutic efficacies of anti-inflammatory drugs. Triptolide is further encapsulated in hybrid micelles for orthotopic tumor therapies. The final multifunctional nanoplatforms (HAOPTs) with hyaluronic acid (HA) modification can target tumor efficiently, inhibit tumor cell EMT processes, repress metastasis establishment and suppress metastatic tumor development in a synergistic manner. Collectively, the results afford proof of concept that the tumor targeting anti-inflammatory nanoplatform can provide a potent, safe and clinical translational approach for EMT inhibition and metastatic tumor therapy.

The function of Sphingosine-1-phosphate receptor 2 (S1PR2) in maintaining intestinal barrier and inducing ulcerative colitis

Sphingosine-1-phosphate receptor 2 (S1PR2) was highly expressed in intestinal epithelial cells (IECs) and facilitated the proliferation of IECs. However, the specific function of S1PR2 in intestinal diseases, such as ulcerative colitis (UC), remains unclear. Accordingly, the current study set out to investigate the function of S1PR2 in maintaining intestinal barrier and inducing UC. S1PR2-overexpressed and knockdown Caco-2 cells were established to explore the function of S1PR2 on the permeability of IECs barrier. The UC-like mouse model in which UC is induced by dextran sulfate sodium (DSS) was established and utilized to investigate the role for S1PR2. The results showed that S1PR2 functioned as a maintainer of IECs permeability and a pathogenic factor for UC. A series of in vitro and in vivo experiments were conducted, and it was found that S1PR2 played an important role in intestinal epithelial cell proliferation and maintenance of intestinal epithelial cell barrier, possibly by the regulation on the expression level of SphK2, HDAC1, HDAC2, and ERK1/2 signaling pathway. The expression of S1PR2 was upregulated in UC mice and the colonic pathological damage in UC mice could be alleviated by the inhibition of S1PR2. Collectively, these results suggest that S1PR2 functions as a maintainer of IECs permeability and a pathogenic factor for UC. The research suggests S1PR2 may be an effective target for developing therapeutic strategies against UC.

Abbreviations: S1PR2, Sphingosine-1-phosphate receptor 2; UC, ulcerative colitis; IECs, intestinal epithelial cells; DSS, dextran sulfate sodium; IBD, inflammation bowel disease; CD, Crohn’s disease; S1P, sphingosin-1-phosphate; SphK, sphingosine kinase; HIECs, human IECs; siRNA, small interfering RNA; CCK-8, cell counting kit-8; TEER, transepithelial electrical resistance; TEM, transmission electron microscope; RT-PCR, real-time reverse transcriptase polymerase-chain reaction; ELISA, enzyme-linked immunosorbent assay; HE, hematoxylin and eosin.

Histone deacetylase 2 polymorphisms associated with noise-induced hearing loss in Chinese workers

Noise-induced hearing loss (NIHL) is one of these hazards which has been the second most common sensorineural hearing loss. Single-nucleotide polymorphisms (SNPs) mainly refer to the polymorphism of DNA sequence caused by the variation at the genomic nucleotide level. The influence of histone deacetylase 2 (HDAC2) variants on the risk of NIHL has not been studied. This research explored the association between HDAC2 and the development of NIHL. A total of 1146 industrial workers from one textile factory in east China were recruited to perform a case-control study. Basic clinical data such sex, age, smoking, and drinking was obtained by questionnaires; pure-toneaudiometry (PTA) tests were conducted by specialist physicians. Then, we performed genotyping of five selected SNPs (rs10499080, rs2475631, rs2499618, rs6568819, and rs3757016) in the HDAC2 gene in 600 NIHL patients and 546 controls. Finally, the main influences of the SNPs and their interactions with NIHL were assessed. Under the recessive model, there were statistically significant differences in the genotype frequencies of rs10499080 between two groups, and the results showed that individuals with rs10499080 CC+CT had a lower risk of NIHL (OR = 0.597, 95%CI = 0.357-0.998). Meanwhile, the significant difference in the genotype distributions between cases and controls was found in rs10499080 in the group with noise exposure of ≤ 16 years. But the following haplotype analysis showed that no association between all haplotypes in the HDAC2 gene and NIHL was been found. The genetic polymorphisms rs10499080 and rs6568819 within HDAC2 gene have an association with risk of NIHL. Workers exposed to noise with HDAC2 have a lower risk of NIHL.

Efficient Synthesis and Bioevaluation of Novel Dual Tubulin/Histone Deacetylase 3 Inhibitors as Potential Anticancer Agents

Novel dual HDAC3/tubulin inhibitors were designed and efficiently synthesized by combining the pharmacophores of SMART (tubulin inhibitor) and MS-275 (HDAC inhibitor), among which compound 15c was found to be the most potent and balanced HDAC3/tubulin dual inhibitor with high HDAC3 activity (IC50 = 30 nM) and selectivity (SI > 1000) as well as excellent antiproliferative potency against various cancer cell lines, including an HDAC-resistant gastric cancer cell line (YCC3/7) with IC50 values in the range of 30-144 nM. Compound 15c inhibited B16-F10 cancer cell migration and colony formation. In addition, 15c demonstrated significant in vivo antitumor efficacy in a B16-F10 melanoma tumor model with a better TGI (70.00%, 10 mg/kg) than that of the combination of MS-275 and SMART. Finally, 15c presented a safe cardiotoxicity profile and did not cause nephro-/hepatotoxicity. Collectively, this work shows that compound 15c represents a novel tubulin/HDAC3 dual-targeting agent deserving further investigation as a potential anticancer agent.

Recent developments in epigenetic cancer therapeutics: clinical advancement and emerging trends

Epigenetic drug discovery field has evidenced significant advancement in the recent times. A plethora of small molecule inhibitors have progressed to clinical stage investigations and are being explored exhaustively to ascertain conclusive benefits in diverse malignancies. Literature precedents indicates that substantial amount of efforts were directed towards the use of epigenetic tools in monotherapy as well as in combination regimens at the clinical level, however, the preclinical/preliminary explorations were inclined towards the identification of prudent approaches that can leverage the anticancer potential of small molecule epigenetic inhibitors as single agents only. This review article presents an update of FDA approved epigenetic drugs along with the epigenetic inhibitors undergoing clinical stage investigations in different cancer types. A detailed discussion of the pragmatic strategies that are expected to steer the progress of the epigenetic therapy through the implementation of emerging approaches such as PROTACS and CRISPR/Cas9 along with logical ways for scaffold fabrication to selectively approach the enzyme isoforms in pursuit of garnering amplified antitumor effects has been covered. In addition, the compilation also presents the rational strategies for the construction of multi-targeting scaffold assemblages employing previously identified pharmacophores as potential alternatives to the combination therapy.

Entinostat improves acute neurological outcomes and attenuates hematoma volume after Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) or hemorrhagic stroke is a major public health problem with no effective treatment. Given the emerging role of epigenetic mechanisms in the pathophysiology of ICH, we tested the hypothesis that a class 1 histone deacetylase inhibitor (HDACi), Entinostat, attenuates neurodegeneration and improves neurobehavioral outcomes after ICH. To address this, we employed a preclinical mouse model of ICH and Entinostat was administered intraperitoneally one-hour post induction of ICH. Entinostat treatment significantly reduced the number of degenerating neurons and TUNEL-positive cells after ICH in comparison to vehicle-treated controls. Moreover, Entinostat treatment significantly reduced hematoma volume, T2-weighted hemorrhagic lesion volume and improved acute neurological outcomes after ICH. Further, Entinostat significantly reduced the hemin-induced release of proinflammatory cytokines in vitro. Consistently, the expression of proinflammatory microglial/macrophage marker, CD16/32, was remarkably reduced in Entinostat treated group after ICH in comparison to control. Altogether, data implicates the potential of class 1 HDACi, Entinostat, in improving acute neurological function after ICH warranting further investigation.

Histone deacetylases as targets in autoimmune and autoinflammatory diseases

Reversible lysine acetylation of histones is a key epigenetic regulatory process controlling gene expression. Reversible histone acetylation is mediated by two opposing enzyme families: histone acetyltransferases (HATs) and histone deacetylases (HDACs). Moreover, many non-histone targets of HATs and HDACs are known, suggesting a crucial role for lysine acetylation as a posttranslational modification on the cellular proteome and protein function far beyond chromatin-mediated gene regulation. The HDAC family consists of 18 members and pan-HDAC inhibitors (HDACi) are clinically used for the treatment of certain types of cancer. HDACi or individual HDAC member-deficient (cell lineage-specific) mice have also been tested in a large number of preclinical mouse models for several autoimmune and autoinflammatory diseases and in most cases HDACi treatment results in an attenuation of clinical disease severity. A reduction of disease severity has also been observed in mice lacking certain HDAC members. This indicates a high therapeutic potential of isoform-selective HDACi for immune-mediated diseases. Isoform-selective HDACi and thus targeted inactivation of HDAC isoforms might also overcome the adverse effects of current clinically approved pan-HDACi. This review provides a brief overview about the fundamental function of HDACs as epigenetic regulators, highlights the roles of HDACs beyond chromatin-mediated control of gene expression and summarizes the studies showing the impact of HDAC inhibitors and genetic deficiencies of HDAC members for the outcome of autoimmune and autoinflammatory diseases with a focus on rheumatoid arthritis, inflammatory bowel disease and experimental autoimmune encephalomyelitis (EAE) as an animal model of multiple sclerosis.

Purine/purine isoster based scaffolds as new derivatives of benzamide class of HDAC inhibitors

This study reports the design, synthesis and evaluation of a series of histone deacetylase (HDAC) inhibitors containing purine/purine isoster as a capping group and an N-(2-aminophenyl)-benzamide unit. In vitro cytotoxicity studies reveal that benzamide 14 suppressed the growth of triple-negative breast cancer cells MDA-MB-231 (IC₅₀ = 1.48 μM), MDA-MB-468 (IC₅₀ = 0.65 μM), and liver cancer cells HepG2 (IC₅₀ = 2.44 μM), better than MS-275 (5) and Chidamide (6). Compared to the well-known HDAC inhibitor SAHA, 14 showed a higher toxicity (IC₅₀ = 0.33 μM) in three leukemic cell lines, K-562, KG-1 and THP-1. Moreover, 14 was found to be equally virulent in the HDAC-sensitive and -resistant gastric cell lines, YCC11 and YCC3/7, respectively, indicating the potential of 14 to overcome HDACi resistance. Furthermore, substantial inhibitory effects more pronounced than MS-275 (5) and Chidamide (6) were displayed by 14 towards HDAC1, 2 and 3 isoforms with IC₅₀ values of 0.108, 0.585 and 0.563 μM respectively. Compound 14 also exhibited a potent antitumor efficacy in human MDA-MB-231 breast cancer xenograft mouse model, providing a potential lead for the development of anticancer agents.

Inhibitory selectivity among class I HDACs has a major impact on inflammatory gene expression in macrophages

Histone deacetylases (HDACs) play an important role in cancer, degenerative diseases and inflammation. The currently applied HDAC inhibitors in the clinic lack selectivity among HDAC isoforms, which limits their application for novel indications such as inflammatory diseases. Recent, literature indicates that HDAC 3 plays an important role among class I HDACs in gene expression in inflammation. In this perspective, the development and understanding of inhibitory selectivity among HDACs 1, 2 and 3 and their respective influence on gene expression need to be characterized to facilitate drug discovery. Towards this aim, we synthesized nine structural analogues of the class I HDAC inhibitor Entinostat and investigated their selectivity profile among HDACs 1, 2 and 3. We found that we can explain the observed structure activity relationships by small structural and conformational differences between HDAC 1 and HDAC 3 in the 'lid' interacting region. Cell-based studies indicated, however, that application of inhibitors with improved HDAC 3 selectivity did not provide an anti-inflammatory response in contrast to expectations from biochemical evidence in literature. Altogether, in this study, we identified structure activity relationships among class I HDACs and we connected isoform selectivity among class I HDACs with pro- and anti-inflammatory gene transcription in macrophages.

Inhibition of Histone Deacetylases Attenuates Morphine Tolerance and Restores MOR Expression in the DRG of BCP Rats

The easily developed morphine tolerance in bone cancer pain (BCP) significantly hindered its clinical use. Increasing evidence suggests that histone deacetylases (HDACs) regulate analgesic tolerance subsequent to continuous opioid exposure. However, whether HDACs contribute to morphine tolerance in the pathogenesis of BCP is still unknown. In the current study, we explored the possible engagement of HDACs in morphine tolerance during the pathogenesis of BCP. After intra-tibia tumor cell inoculation (TCI), we found that the increased expression of HDACs was negatively correlated with the decreased expression of MOR in the DRG following TCI. The paw withdrawal threshold (PWT) and percentage maximum possible effects (MPEs) decreased rapidly in TCI rats when morphine was used alone. In contrast, the concomitant use of SAHA and morphine significantly elevated the PWT and MPEs of TCI rats compared to morphine alone. Additionally, we found that SAHA administration significantly elevated MOR expression in the DRG of TCI rats with or without morphine treatment. Moreover, the TCI-induced increase in the co-expression of MOR and HDAC1 in neurons was significantly decreased after SAHA administration. These results suggest that HDACs are correlated with the downregulation of MOR in the DRG during the pathogenesis of BCP. Inhibition of HDACs using SAHA can be used to attenuate morphine tolerance in BCP.

The SphKs/S1P/S1PR1 axis in immunity and cancer: more ore to be mined

Over the past two decades, huge amounts of research were launched to understand the functions of sphingosine. Many pathways were uncovered that convey the relative functions of biomacromolecules. In this review, we discuss the recent advances of the role of the SphKs/S1P/S1PR1 axis in immunity and cancer. Finally, we investigate the therapeutic potential of new drugs that target S1P signaling in cancer therapy.

Mechanistic roles of epithelial and immune cell signaling during the development of colitis-associated cancer

To date, substantial evidence has shown a significant association between inflammatory bowel diseases (IBD) and development of colitis-associated cancer (CAC). The incidence/prevalence of IBD is higher in western countries including the US, Australia, and the UK. Although CAC development is generally characterized by stepwise accumulation of genetic as well as epigenetic changes, precise mechanisms of how chronic inflammation leads to the development of CAC are largely unknown. Preceding intestinal inflammation is one of the major influential factors for CAC tumorigenesis. Mucosal immune responses including activation of aberrant signaling pathways both in innate and adaptive immune cells play a pivotal role in CAC. Tumor progression and metastasis are shaped by a tightly controlled tumor microenvironment which is orchestrated by several immune cells and stromal cells including macrophages, neutrophils, dendritic cells, myeloid derived suppressor cells, T cells, and myofibroblasts. In this article, we will discuss the contributing factors of epithelial as well as immune cell signaling in initiation of CAC tumorigenesis and mucosal immune regulatory factors in the colonic tumor microenvironment. In depth understanding of these factors is necessary to develop novel anti-inflammatory and anti-cancer therapies for CAC in the near future.

Synthesis, biological characterization and molecular modeling insights of spirochromanes as potent HDAC inhibitors

In the last decades, inhibitors of histone deacetylases (HDAC) have become an important class of anti-cancer agents. In a previous study we described the synthesis of spiro[chromane-2,4'-piperidine]hydroxamic acid derivatives able to inhibit histone deacetylase enzymes. Herein, we present our exploration for new derivatives by replacing the piperidine moiety with various cycloamines. The goal was to obtain highly potent compounds with a good in vitro ADME profile. In addition, molecular modeling studies unravelled the binding mode of these inhibitors.

Never in mitosis gene A-related kinase 6 and aurora kinase A: New gene biomarkers in the conversion from ulcerative colitis to colorectal cancer

Ulcerative colitis (UC) is an important risk factor for colorectal cancer (CRC). Histone modifications are one of the epigenetic mechanisms that may have key roles in the carcinogenesis of CRC. At present, there are no studies comparing histone modification patterns of UC and CRC in the literature. Therefore the aim of the present study was to investigate whether genes, particularly those involved in histone modification, have value in patient monitoring with regards to CRC development in UC. Key gene expressions of the histone modification enzyme were assessed and compared in CRC, UC and control groups using the RT-PCR array technique. Patients were divided into subgroups based on the extent and duration of the disease and inflammatory burden, which are considered risk factors for CRC development in UC patients. In UC and CRC groups, a significantly higher overexpression of the NEK6 and AURKA genes compared to the control group was identified. In addition, there was a significantly higher overexpression of HDAC1 and PAK1 genes in the UC group, and of HDAC1, HDAC7, PAK1 and AURKB genes in the CRC group. NEK6, AURKA, HDAC1 and PAK1 were significantly overexpressed in patients with a longer UC duration. Overexpression of AURKA and NEK6 genes was significantly more pronounced in UC patients with more extensive colon involvement. HDAC1, HDAC7, PAK1, NEK6, AURKA and AURKB are important diagnostic and prognostic markers involved in the carcinogenesis of CRC. HDAC1, PAK1, NEK6 and AURKA may be considered as diagnostic markers to be used in CRC screening for UC patients.

Selective, potent blockade of the IRE1 and ATF6 pathways by 4-phenylbutyric acid analogues

BACKGROUND AND PURPOSE

4-Phenylbutyric acid (4-PBA) is a chemical chaperone that eliminates the accumulation of unfolded proteins in the endoplasmic reticulum (ER). However, its chaperoning ability is often weak and unable to attenuate the unfolded protein response (UPR) in vitro or in vivo. To develop more potent chemical chaperones, we synthesized six analogues of 4-PBA and evaluated their pharmacological actions on the UPR.

EXPERIMENTAL APPROACH

NRK-52E cells were treated with ER stress inducers (tunicamycin or thapsigargin) in the presence of each of the 4-PBA analogues; the suppressive effects of these analogues on the UPR were assessed using selective indicators for individual UPR pathways.

KEY RESULTS

2-POAA-OMe, 2-POAA-NO2 and 2-NOAA, but not others, suppressed the induction of ER stress markers GRP78 and CHOP. This suppressive effect was more potent than that of 4-PBA. Of the three major UPR branches, the IRE1 and ATF6 pathways were markedly blocked by these compounds, as indicated by suppression of XBP1 splicing, inhibition of UPRE and ERSE activation, and inhibition of JNK phosphorylation. Unexpectedly, however, these agents did not inhibit phosphorylation of PERK and eIF2α triggered by ER stress. These compounds dose-dependently inhibited the early activation of NF-κB in ER stress-exposed cells. 2-POAA-OMe and 2-POAA-NO2 also inhibited ER stress-induced phosphorylation of Akt.

CONCLUSION AND IMPLICATIONS

The 4-PBA analogues 2-POAA-OMe, 2-POAA-NO2 and 2-NOAA strongly inhibited activation of the IRE1 and ATF6 pathways and downstream pathogenic targets, including NF-κB and Akt, in ER stress-exposed cells. These compounds may be useful for therapeutic intervention in ER stress-related pathological conditions.

Vorinostat, a HDAC inhibitor, showed anti-osteoarthritic activities through inhibition of iNOS and MMP expression, p38 and ERK phosphorylation and blocking NF-κB nuclear translocation

Overproduction of nitric oxide (NO) and matrix metalloproteinases (MMPs) plays an important role in the pathogenesis of osteoarthritis (OA). In present study, we investigated whether vorinostat can inhibit the catabolic effects of IL-1β in vitro, especially the inhibition of MMPs and inducible nitric oxide synthase (iNOS) through the attenuation of nuclear factor kappa-B (NF-κB) and mitogen activated protein kinase (MAPK) pathways in human chondrocytes. Human OA chondrocytes were either left untreated or treated with various concentrations of vorinostat followed by incubation with IL-1β (5ng/mL). Effects of vorinostat on IL-1β-induced gene and protein expression of iNOS, MMP-1, MMP-13 and tissue inhibitors of metalloproteinase-1 (TIMP-1) were verified by quantitative real time-PCR and Western blot analysis. Production of NO, MMP-1, MMP-13 and TIMP-1 released in culture supernatant was estimated using commercially available kits. The roles of NF-κB and MAPK pathways in the regulation of targeted genes and the mechanism involved in vorinostat mediated modulation of these genes were determined by Western blot using specific antibodies. We found that vorinostat down-regulated iNOS, MMP-1 and MMP-13 expression and up-regulated TIMP-1 expression in human OA chondrocytes. In addition, the release of NO, MMP-1 and MMP-13 secreted from IL-1β stimulated chondrocytes was also suppressed by vorinostat. Interestingly, vorinostat selectively inhibited IL-1β-induced p38 and ERK1/2 activation without affecting JNK activation. Furthermore, we observed that vorinostat inhibited NF-κB pathway by suppressing the degradation of I-κBα and attenuating NF-κB p65 translocation to the nucleus. These results suggest that vorinostat may be a promising therapeutic agent for the prevention and treatment of OA.

Determination and stress studies on YK-1101, a potential histone deacetylase, by HPLC–UV and HPLC–TOF/MS methods

YK-1101, with its structure as S-((E)-4-((7S,10S,Z)-4-ethylidene-7-isopropyl-2,5,8,12-tetraoxo -9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl) ethanethioate, is synthesized as a potential histone deacetylase inhibitor. Its quality and stability under various stress conditions are not fully understood. In this study, a high performance liquid chromatographic (HPLC) method was established and validated for the analysis of YK-1101 bulk drug samples. The chromatographic separation was performed on a C₁₈ column with acetonitrile and water as mobile phase in a gradient elution. Based on the established method, the stability studies of YK-1101 under various stress conditions were carried out. YK-1101 was shown to undergo degradation under basic and acidic stress conditions, while it was stable under oxidative, photolytic and thermal conditions. In addition, a time of flight mass spectrometer (TOF/MS) was coupled to HPLC for the characterization of major degradation products produced under basic and acidic stress conditions. Their degradation pathways were also discussed.

Oral administration of histone deacetylase inhibitor MS-275 ameliorates neuroinflammation and cerebral amyloidosis and improves behavior in a mouse model

Alzheimer disease is the most common neurodegenerative disease and the major cause of dementia. In addition to β-amyloid aggregation and hyperphosphorylated tau, neuroinflammation also plays important roles in the pathophysiology of this multifactorial disorder. Histone deacetylase catalyzes deacetylation of histones and has important roles in the regulation of gene expression. Histone deacetylase inhibitors have been reported to exhibit neuroprotective and anti-neuroinflammatory activities and have therapeutic effects in several animal models of neurodegenerative diseases. Here, an efficient benzamide histone deacetylase inhibitor, MS-275, was orally administered by gavage to transgenic APP/PS1 mice, an animal model of cerebral amyloidosis for Alzheimer disease. After 10 days of treatment, MS-275 significantly ameliorated microglial activation and β-amyloid deposition in cerebral cortex and/or hippocampus. This was associated with improved nesting behavior, an important affiliative/social behavior. MS-275 also attenuated inflammatory activation of a mouse macrophage cell line in vitro. These results suggest that MS-275 may be a therapeutic option for Alzheimer disease and other neuroinflammatory diseases.

Identification of novel compounds that enhance colon cancer cell sensitivity to inflammatory apoptotic ligands

Immune and inflammatory death ligands expressed within neoplastic tissue could potentially target apoptosis to transformed cells. To develop approaches that accentuate the anti-cancer potential of the inflammatory response, the Chembridge DIVERSet (TM) library was screened for compounds that accentuated apoptosis in a strictly TNF-dependent manner. We identified a number of novel compounds with this activity, the most active of these, AK3 and AK10, sensitized colon cancer cells to TNF at 0.5 μM and 2 μM, respectively, without inducing apoptosis on their own. The activity of these compounds was structure-dependent and general, as they accentuated cell death by TNF or Fas ligation in multiple colon cancer cell lines. Both AK3 and AK10 arrested cells in mitosis, with live cell imaging indicating that mitotically arrested cells were the source of apoptotic bodies. AK3 accentuated caspase-8 and caspase-9 activation with little effect on NFκB target gene activation. Enhanced caspase activation corresponded to an increased expression of TNFR1 on the cell surface. To determine the general interplay between mitotic arrest and TNF sensitivity, Aurora kinase (MLN8054 and MLN8237) and PLK1 (BI2536) inhibitors were tested for their ability to sensitize cells to TNF. PLK1 inhibition was particularly effective and influenced TNFR1 surface presentation and caspase cleavage like AK3, even though it arrested mitosis at an earlier stage. We propose that AK3 and AK10 represent a new class of mitotic inhibitor and that selected mitotic inhibitors may be useful for treating colon cancers or earlier lesions that have a high level of inflammatory cell infiltrate.

Low concentration of S100A8/9 promotes angiogenesis-related activity of vascular endothelial cells: bridges among inflammation, angiogenesis, and tumorigenesis?

Previous studies showed that several members of the S100A family are involved in neovascularization and tumor development. This study checked whether low concentrations of S100A8 or S100A9 has any effect on the behaviour of vascular endothelial cells. A human umbilical vascular endothelial cell (HUVEC) line was used to measure vascular endothelial cell bioactivity related to angiogenesis, such as cell proliferation, migration, and vessel formation. In the low concentration range up to 10 μg/mL, either each alone or in combination, S100A8 and S100A9 proteins promoted proliferation of HUVEC cells in a dose-dependent manner. The presence of both proteins in culture showed additive effects over each single protein. Both proteins enhanced HUVEC cells to migrate across the transwell membrane and to form tube-like structures on the Matrigel surface. When mixed in Matrigel and injected subcutaneously in Balb/c mice, both proteins increased vessel development in the gel plugs. Microarray assay of HUVEC cells treated with 10 μg/mL S100A8 revealed that ribosome pathway, pathogenic Escherichia coli infection pathway, apoptosis, and stress response genes were modulated by S100A8 treatment. We propose that S100A8 and S100A9 proteins from either infiltrating inflammatory cells or tumor cells play an important role in the interplay among inflammation, angiogenesis, and tumorigenesis.

Regulation of immune responses by histone deacetylase inhibitors

Both genetic and epigenetic factors are important regulators of the immune system. There is an increasing body of evidence attesting to epigenetic modifications that influence the development of distinct innate and adaptive immune response cells. Chromatin remodelling via acetylation, methylation, phosphorylation, and ubiquitination of histone proteins as well as DNA, methylation is epigenetic mechanisms by which immune gene expression can be controlled. In this paper, we will discuss the role of epigenetics in the regulation of host immunity, with particular emphasis on histone deacetylase inhibitors. In particular, the role of HDAC inhibitors as a new class of immunomodulatory therapeutics will also be reviewed.

HDAC inhibitor MS-275 attenuates the inflammatory reaction in rat experimental autoimmune prostatitis

BACKGROUND

Experimental autoimmune prostatitis (EAP) is an autoimmune inflammatory disease of male sex accessory glands and is characterized by a cellular and humoral prostate-specific autoimmune response. EAP shares important clinical and immunological features with human chronic prostatitis and chronic pelvic pain syndrome. MS-275, a potent histone deacetylase inhibitor, has promising anti-inflammatory activities and might be a new agent in the therapy of prostate inflammation.

METHODS

EAP rats were treated with MS-275 (5 mg/kg, i.p.) once daily. Using immunohistochemistry and PCR assay, we determined immune cellular responses and infiltration into the prostate glands, and changes of mRNA levels of representative inflammatory molecules in prostate tissue. Changes in Foxp3(+) CD4(+) cell populations of lymph nodes and peripheral blood were analyzed by flow cytometry. Additionally, direct anti-inflammatory effects of MS-275 were investigated in vitro with a macrophage cell line.

RESULTS

MS-275 treatment significantly reduced the local accumulation of immune cells and mRNA levels of representative pro-inflammatory molecules in prostate tissue. Furthermore, MS-275 treatment increased percentage of Foxp3(+) CD4(+) Treg cells in lymph nodes and their proportion to CD4(+) cells in peripheral blood, and induced a relative increase of ED2(+) macrophage numbers in EAP prostate. Additional in vitro study showed that MS-275 induced a switch of macrophages from classic M1 to anti-inflammatory M2 phenotype.

CONCLUSIONS

In summary, our data demonstrated that MS-275 could effectively suppress inflammatory reaction in EAP, through suppressing immune cells and pro-inflammatory molecules, and inducing anti-inflammatory immune cells and molecules, which may suggest MS-275 as a potential candidate for treatment of inflammatory prostatitis.

Characterization of chromosomal instability in murine colitis-associated colorectal cancer

Background

Patients suffering from ulcerative colitis (UC) bear an increased risk for colorectal cancer. Due to the sparsity of colitis-associated cancer (CAC) and the long duration between UC initiation and overt carcinoma, elucidating mechanisms of inflammation-associated carcinogenesis in the gut is particularly challenging. Adequate murine models are thus highly desirable. For human CACs a high frequency of chromosomal instability (CIN) reflected by aneuploidy could be shown, exceeding that of sporadic carcinomas. The aim of this study was to analyze mouse models of CAC with regard to CIN. Additionally, protein expression of p53, beta-catenin and Ki67 was measured to further characterize murine tumor development in comparison to UC-associated carcinogenesis in men.

Methods

The AOM/DSS model (n = 23) and IL-10^−/− mice (n = 8) were applied to monitor malignancy development via endoscopy and to analyze premalignant and malignant stages of CACs. CIN was assessed using DNA-image cytometry. Protein expression of p53, beta-catenin and Ki67 was evaluated by immunohistochemistry. The degree of inflammation was analyzed by histology and paralleled to local interferon-γ release.

Results

CIN was detected in 81.25% of all murine CACs induced by AOM/DSS, while all carcinomas that arose in IL-10^−/− mice were chromosomally stable. Beta-catenin expression was strongly membranous in IL-10^−/− mice, while 87.50% of AOM/DSS-induced tumors showed cytoplasmatic and/or nuclear translocation of beta-catenin. p53 expression was high in both models and Ki67 staining revealed higher proliferation of IL-10^−/−-induced CACs.

Conclusions

AOM/DSS-colitis, but not IL-10^−/− mice, could provide a powerful murine model to mechanistically investigate CIN in colitis-associated carcinogenesis.

The outs and the ins of sphingosine-1-phosphate in immunity

The potent lipid mediator sphingosine-1-phosphate (S1P) is produced inside cells by two closely related kinases, sphingosine kinase 1 (SPHK1) and SPHK2, and has emerged as a crucial regulator of immunity. Many of the actions of S1P in innate and adaptive immunity are mediated by its binding to five G protein-coupled receptors, designated S1PR1-5, but recent findings have also identified important roles for S1P as a second messenger during inflammation. In this Review, we discuss recent advances in our understanding of the roles of S1P receptors and describe the newly identified intracellular targets of S1P that are crucial for immune responses. Finally, we discuss the therapeutic potential of new drugs that target S1P signalling and functions.

Proteostasis: a new therapeutic paradigm for pulmonary disease

Among lung pathologies, α1AT, chronic obstructive pulmonary disease (COPD), emphysema, and asthma are diseases triggered by local environmental stress in the airway that we refer to herein collectively as airway stress diseases (ASDs). A deficiency of α-1-antitrypsin (α1AT) is an inherited genetic disorder that is a consequence of the misfolding of α1AT during protein synthesis in liver hepatocytes, reducing secretion to the plasma and delivery to the lung. Deficiency of α1AT in the lung triggers a similar pathological phenotype to other ASDs. Moreover, the loss of α1AT in the lung is a well-known environmental risk factor for COPD/emphysema. To date there are no effective therapeutic approaches to address ASDs, which reflects a general lack of understanding of their cellular basis. Herein, we propose that ASDs are disorders of proteostasis. That is, they are initiated and propagated by a common theme-a challenge to protein folding capacity maintained by the proteostasis network (PN) (see Balch et al., Science 2008;319:916-919). The PN is a network of chaperones and degradative components that generates and manages protein folding pathways responsible for normal human physiology. In ASD, we suggest that the PN system fails to respond to the increased burden of unfolded proteins due to genetic and environmental stresses, thus triggering pulmonary pathophysiology. We introduce the enabling concept of proteostasis regulators (PRs), small molecules that regulate signaling pathways that control the composition and activity of PN components, as a new and general approach for therapeutic management of ASDs.

Rationale for HDAC inhibitor therapy in autoimmunity and transplantation

While there are currently more than 70 ongoing clinical trials of inhibitors of so-called classical HDACs (HDACi) as anticancer therapies, given their potency as antiproliferative and angiostatic agents, HDACi also have considerable therapeutic potential as anti-inflammatory and immunosuppressive drugs. The utility of HDACi as anti-inflammatory agents is dependent upon their proving safe and effective in experimental models. Current pan-HDACi compounds are not well suited to this role, given the broad distribution of target HDACs and their complex and multifaceted mechanisms of action. In contrast, the development of isoform-selective HDACi may provide important new tools for therapy in autoimmunity and transplantation. This chapter discusses which HDACs are worthwhile targets in inflammation and progress toward their therapeutic inhibition, including the use of HDAC subclass and isoform-selective HDACi to promote the functions of Foxp3+ T regulatory cells.

Cell type-specific regulation of IL-10 expression in inflammation and disease

IL-10 plays an essential part in controlling inflammation and instructing adaptive immune responses. Consequently, dysregulation of IL-10 is linked with susceptibility to numerous infectious and autoimmune diseases in mouse models and in humans. It has become increasingly clear that appropriate temporal/spatial expression of IL-10 may be the key to how IL-10 contributes to the delicate balance between inflammation and immunoregulation. The mechanisms that govern the cell type- and receptor-specific induction of IL-10, however, remain unclear. This is due largely to the wide distribution of cellular sources that express IL-10 under diverse stimulation conditions and in a variety of tissue compartments. Further complicating the issue is the fact that human IL-10 expression patterns appear to be under genetic influence resulting in differential expression and disease susceptibility. In this review, we discuss the cellular sources of IL-10, their link to disease phenotypes and the molecular mechanisms implicated in IL-10 regulation.

Inhibition of class II histone deacetylases in the spinal cord attenuates inflammatory hyperalgesia

Background

Several classes of histone deacetylases (HDACs) are expressed in the spinal cord that is a critical structure of the nociceptive pathway. HDAC-regulated histone acetylation is an important component of chromatin remodeling leading to epigenetic regulation of gene transcription. To understand the role of histone acetylation in epigenetic regulation of pathological pain, we have studied the impact of different classes of HDACs in the spinal cord on inflammatory hyperalgesia induced by complete Freund's adjuvant (CFA).

Results

We intrathecally applied inhibitors specific to different classes of HDACs and evaluated their impact on inflammatory hyperalgesia. Pre-injected inhibitors targeting class I as well as II (SAHA, TSA, LAQ824) or IIa (VPA, 4-PB) HDACs significantly delayed the thermal hyperalgesia induced by unilateral CFA injection in the hindpaw. Existing hyperalgesia induced by CFA was also attenuated by the HDAC inhibitors (HDACIs). In contrast, these inhibitors did not interfere with the thermal response either in naïve animals, or on the contralateral side of inflamed animals. Interestingly, MS-275 that specifically inhibits class I HDACs failed to alter the hyperalgesia although it increased histone 3 acetylation in the spinal cord as SAHA did. Using immunoblot analysis, we further found that the levels of class IIa HDAC members (HDAC4, 5, 7, 9) in the spinal dorsal horn were upregulated following CFA injection while those of class I HDAC members (HDAC1, 2, 3) remained stable or were slightly reduced.

Conclusions

Our data suggest that activity of class II HDACs in the spinal cord is critical to the induction and maintenance of inflammatory hyperalgesia induced by CFA, while activity of class I HDACs may be unnecessary. Comparison of the effects of HDACIs specific to class II and IIa as well as the expression pattern of different HDACs in the spinal cord in response to CFA suggests that the members of class IIa HDACs may be potential targets for attenuating persistent inflammatory pain.

Suppression of neurotensin receptor type 1 expression and function by histone deacetylase inhibitors in human colorectal cancers

Neurotensin, a gut peptide, stimulates the growth of colorectal cancers that possess the high-affinity neurotensin receptor (NTR1). Sodium butyrate (NaBT) is a potent histone deacetylase inhibitor (HDACi) that induces growth arrest, differentiation, and apoptosis of colorectal cancers. Previously, we had shown that NaBT increases nuclear GSK-3beta expression and kinase activity; GSK-3beta functions as a negative regulator of extracellular signal-regulated kinase (ERK) signaling. The purpose of our current study was to determine: (a) whether HDACi alters NTR1 expression and function, and (b) the role of GSK-3beta/ERK in NTR1 regulation. Human colorectal cancers with NTR1 were treated with various HDACi, and NTR1 expression and function were assessed. Treatment with HDACi dramatically decreased endogenous NTR1 mRNA, protein, and promoter activity. Overexpression of GSK-3beta decreased NTR1 promoter activity (> 30%); inhibition of GSK-3beta increased NTR1 expression in colorectal cancer cells, indicating that GSK-3beta is a negative regulator of ERK and NTR1. Consistent with our previous findings, HDACi significantly decreased phosphorylated ERK while increasing GSK-3beta. Selective MAP/ERK kinase/ERK inhibitors suppressed NTR1 mRNA expression in a time- and dose-dependent fashion, and reduced NTR1 promoter activity by approximately 70%. Finally, pretreatment with NaBT prevented neurotensin-mediated cyclooxygenase-2 and c-myc expression and attenuated neurotensin-induced interleukin-8 expression. HDACi suppresses endogenous NTR1 expression and function in colorectal cancer cell lines; this effect is mediated, at least in part, through the GSK-3beta/ERK pathway. The downregulation of NTR1 in colorectal cancers may represent an important mechanism for the anticancer effects of HDACi.

Novel application of proton pump inhibitor for the prevention of colitis-induced colorectal carcinogenesis beyond acid suppression

Colitis-associated cancers arise in the setting of chronic inflammation wherein an "inflammation-dysplasia-carcinoma" sequence prevails. Based on our previous findings in which the proton pump inhibitor could impose significant levels of anti-inflammatory, antiangiogenic, and selective apoptosis induction beyond gastric acid suppression, we investigated whether omeprazole could prevent the development of colitis-associated cancer in a mouse model induced by repeated bouts of colitis. Omeprazole, 10 mg/kg, was given i.p. all through the experimental periods for colitis-associated carcinogenesis. Molecular changes regarding inflammation and carcinogenesis were compared between control groups and colitis-associated cancer groups treated with omeprazole in addition to chemopreventive outcome. Nine of 12 (75.0%) mice in the control group developed multiple colorectal tumors, whereas tumors were noted in only 3 of 12 (25.0%) mice treated with daily injections of omeprazole. The cancer-preventive results of omeprazole treatment was based on significant decreases in the levels of nitric oxide, thiobarbituric acid-reactive substance, and interleukin-6 accompanied with attenuated expressions of tumor necrosis factor-alpha, inducible nitric oxide synthase, and cyclooxygenase-2. The expressions of matrix metalloproteinase (MMP)-9, MMP-11, and MT1-MMMP were significantly decreased in mice treated with omeprazole in accordance with significant decreases in the number of beta-catenin-accumulated crypts. A significant induction of apoptosis was observed in tumor tissue treated with omeprazole. Omeprazole could block the trophic effect of gastrin in colon epithelial cells. The significant anti-inflammatory, antioxidative, and antimutagenic activities of omeprazole played a cancer-preventive role against colitis-induced carcinogenesis, and our novel in vivo evidence is suggestive of chemopreventive action independent of gastric acid suppression.

Deacetylase inhibitors - focus on non-histone targets and effects

Inhibitors of protein deacetylases have recently been established as a novel therapeutic principle for several human diseases, including cancer. The original notion of the mechanism of action of these compounds focused on the epigenetic control of transcriptional processes, especially of tumor suppressor genes, by interfering with the acetylation status of nuclear histone proteins, hence the name histone deacetylase inhibitors was coined. Yet, this view could not explain the high specificity for tumor cells and recent evidence now suggests that non-histone proteins represent major targets for protein deacetylase inhibitors and that the post-translational modification of the acetylome is involved in various cellular processes of differentiation, survival and cell death induction.

MS-275, an histone deacetylase inhibitor, reduces the inflammatory reaction in rat experimental autoimmune neuritis

Experimental autoimmune neuritis (EAN) is a T cell-mediated autoimmune inflammatory demyelinating disease of the peripheral nervous system and serves as the animal model of human inflammatory demyelinating polyradiculoneuropathies. MS-275, a potent histone deacetylase inhibitor currently undergoing clinical investigations for various malignancies, has been reported to demonstrate promising anti-inflammatory activities. In our present study, MS-275 administration (3.5 mg/kg i.p.) to EAN rats once daily from the appearance of first neurological signs greatly reduced the severity and duration of EAN and attenuated local accumulation of macrophages, T cells and B cells, and demyelination of sciatic nerves. Further, significant reduction of mRNA levels of pro-inflammatory interleukin-1beta, interferon-gamma, interleukine-17, inducible nitric oxide synthase and matrix metalloproteinase-9 was observed in sciatic nerves of MS-275 treated EAN rats. In lymph nodes, MS-275 depressed pro-inflammatory cytokines as well, but increased expression of anti-inflammatory cytokine interleukine-10 and of foxhead box protein3 (Foxp3), a unique transcription factor of regulatory T cells. In addition, MS-275 treatment increased proportion of infiltrated Foxp3(+) cells and anti-inflammatory M2 macrophages in sciatic nerves of EAN rats. In summary, our data demonstrated that MS-275 could effectively suppress inflammation in EAN, through suppressing inflammatory T cells, macrophages and cytokines, and inducing anti-inflammatory immune cells and molecules, suggesting MS-275 as a potent candidate for treatment of autoimmune neuropathies.