Valproic acid as epigenetic cancer drug: preclinical, clinical and transcriptional effects on solid tumors

Plasma miRNAs in polycystic ovary syndrome drive endometrial cancer progression: insights into molecular pathways and therapeutic targets

Polycystic ovary syndrome (PCOS) is a known risk factor for uterine endometrial cancer (UCEC), but its underlying mechanisms remain unclear. MicroRNAs (miRNAs) could provide insights into these mechanisms and reveal potential therapeutic targets. Differential miRNA expression was analyzed in plasma exosomes from 15 PCOS and 15 control samples. Survival analysis assessed the prognostic value of these miRNAs in UCEC. MiRNA-target gene interaction networks and gene co-expression analyses were used to explore molecular mechanisms. Validation was performed using experimental data from Ishikawa cells treated with six candidate drugs. Among the 15 differentially expressed miRNAs, 12 were up-regulated and 3 were down-regulated in PCOS. Twelve of these miRNAs were associated with UCEC overall survival, with miR-142, miR-424, and miR-331 acting as protective factors, while the remaining 9 miRNAs were identified as risk factors. MiRNA-target network highlighted key genes such as PHF8, LCOR, SFT2D3, E2F1, and ESR1, which were found to be prognostic for patient survival. Further gene expression and co-expression analyses based on miR-424 and miR-330 expression revealed significant alterations in gene expression and cellular processes related to UCEC. Two-sample Mendelian randomization analysis identified potential causal relationships between AURKA gene expression and PCOS or UCEC. Testosterone and estradiol might have adverse roles in UCEC, while drugs like troglitazone, valproic acid, retinoic acid, and progesterone demonstrated various effects on gene expression and cellular processes. Our findings suggest that aberrant miRNA expression, particularly miR-330 and miR-424, may play crucial roles in UCEC progression. The identified miRNAs and candidate drugs may serve as potential therapeutic targets for UCEC, but further research is required to validate and explore their clinical applications.

Cytotoxicity, genotoxicity and mutagenicity of mixed ternary mononuclear Mg complex based on valproic acid with 1,10-phenanthroline in Saccharomyces cerevisiae and V79 cells

Valproic acid (VA) is a widely used drug for the treatment of diseases affecting the central nervous system. Due to its epigenetic modulatory potential, it has been studied for possible therapeutic application in anticancer therapies. However, the VA exhibits different side effects in its application. Thus, synthetic coordination complexes with valproate can generate promising candidates for new active drugs with reduced toxicity. In this sense, we investigated the genotoxic and mutagenic potential of the sodium valproate and of the mixed ternary mononuclear Mg complex based on VA with 1,10-phenanthroline (Phen) ligand - [Mg (Valp)2Phen], in Saccharomyces cerevisiae and V79 cells. The MTT and clonal survival assays in V79 cells indicated that the Mg complex has higher cytotoxicity than sodium valproate. A similar cytotoxicity profile is observed in yeast. This fact is possibly due to the intercalation capacity of [Mg(Valp)2Phen], inducing DNA strand breaks, as observed in the comet assay and micronucleus test. In this sense, members of the NER, HR, NHEJ and TLS repair pathways are required for the repair of DNA lesions induced by [Mg(Valp)2Phen]. Interestingly, BER proteins apparently increase the cytotoxic potential of the drug. Furthermore, the [Mg(Valp)2Phen] showed higher cytotoxicity in V79 cells and yeast when compared to sodium valproate indicating applicability as a cytotoxic agent.

Recent update on anti-tumor mechanisms of valproic acid in glioblastoma multiforme

Glioblastoma multiforme (GBM) is a malignant tumor of the brain that is considered to be incurable. Currently, surgical removal of tumors, chemotherapy with temozolomide, and radiation treatment remain established options for treatment. Nevertheless, the prognosis of those with GBM continues to be poor owing to the inherent characteristics of tumor growth and spread, as well as the resistance to treatment. To effectively deal with the present circumstances, it is vital to do extensive study to understand GBM thoroughly. The following piece provides a concise overview of the most recent advancements in using valproic acid, an antiseizure medication licensed by the FDA, for treating GBM. In this review, we outline the most recent developments of valproic acid in treating GBM, as well as its fundamental mechanisms and practical consequences. Our goal is to provide a greater understanding of the clinical use of valproic acid as a potential therapeutic agent for GBM.

Randomized phase 2 study of valproic acid combined with simvastatin and gemcitabine/nab-paclitaxel-based regimens in untreated metastatic pancreatic adenocarcinoma patients: the VESPA trial study protocol

BACKGROUND

Metastatic pancreatic ductal adenocarcinoma (mPDAC) patients have very poor prognosis highlighting the urgent need of novel treatments. In this regard, repurposing non-oncology already-approved drugs might be an attractive strategy to offer more-effective treatment easily tested in clinical trials. Accumulating evidence suggests that epigenetic deregulation is a hallmark of cancer contributing to treatment resistance in several solid tumors, including PDAC. Histone deacetylase inhibitors (HDACi) are epigenetic drugs we have investigated preclinically and clinically as anticancer agents. Valproic acid (VPA) is a generic low-cost anticonvulsant and mood stabilizer with HDAC inhibitory activity, and anticancer properties also demonstrated in PDAC models. Statins use was reported to be associated with lower mortality risk in patients with pancreatic cancer and statins have been shown to have a direct antitumor effect when used alone or in combination therapy. We recently showed capability of VPA/Simvastatin (SIM) combination to potentiate the antitumor activity of gemcitabine/nab-paclitaxel in vitro and in vivo PDAC preclinical models.

METHODS/DESIGN

VESPA is a patient-centric open label randomized multicenter phase-II investigator-initiated trial, evaluating the feasibility, safety, and efficacy of VPA/SIM plus first line gemcitabine/nab-paclitaxel-based regimens (AG or PAXG) (experimental arm) versus chemotherapy alone (standard arm) in mPDAC patients. The study involves Italian and Spanish oncology centers and includes an initial 6-patients safety run-in-phase. A sample size of 240 patients (120 for each arm) was calculated under the hypothesis that the addition of VPA/SIM to gemcitabine and nab-paclitaxel-based regimens may extend progression free survival from 6 to 9 months in the experimental arm. Secondary endpoints are overall survival, response rate, disease control rate, duration of response, CA 19.9 reduction, toxicity, and quality of life. The study includes a patient engagement plan and complementary biomarkers studies on tumor and blood samples.

CONCLUSIONS

VESPA is the first trial evaluating efficacy and safety of two repurposed drugs in oncology such as VPA and SIM, in combination with standard chemotherapy, with the aim of improving mPDAC survival. The study is ongoing. Enrollment started in June 2023 and a total of 63 patients have been enrolled as of June 2024.

TRIAL REGISTRATION

EudraCT number: 2022-004154-63; ClinicalTrials.gov identifier NCT05821556, posted 2023/04/20.

Histone deacetylase inhibition mitigates fibrosis-driven disease progression in recessive dystrophic epidermolysis bullosa

BACKGROUND

Recessive dystrophic epidermolysis bullosa (RDEB) is a blistering disease caused by mutations in the gene encoding type VII collagen (C7). RDEB is associated with fibrosis, which is responsible for severe complications. The phenotypic variability observed in siblings with RDEB suggests that epigenetic modifications contribute to disease severity. Identifying epigenetic changes may help to uncover molecular mechanisms underlying RDEB pathogenesis and new therapeutic targets.

OBJECTIVES

To investigate histone acetylation in RDEB skin and to explore histone deacetylase inhibitors (HDACi) as therapeutic molecules capable of counteracting fibrosis and disease progression in RDEB mice.

METHODS

Acetylated histone levels were detected in human skin by immunofluorescence and in RDEB fibroblasts by enzyme-linked immunosorbent assay (ELISA). The effects of givinostat and valproic acid (VPA) on RDEB fibroblast fibrotic behaviour were assessed by a collagen-gel contraction assay, Western blot and immunocytofluorescence for α-smooth muscle actin, and ELISA for released transforming growth factor (TGF)-β1. RNA sequencing was performed in HDACi- and vehicle-treated RDEB fibroblasts. VPA was systemically administered to RDEB mice and effects on overt phenotype were monitored. Fibrosis was investigated in the skin using histological and immunofluorescence analyses. Eye and tongue defects were examined microscopically. Mass spectrometry proteomics was performed on skin protein extracts from VPA-treated RDEB and control mice.

RESULTS

Histone acetylation decreases in RDEB skin and primary fibroblasts. RDEB fibroblasts treated with HDACi lowered fibrotic traits, including contractility, TGF-β1 release and proliferation. VPA administration to RDEB mice mitigated severe manifestations affecting the eyes and paws. These effects were associated with fibrosis inhibition. Proteomic analysis of mouse skin revealed that VPA almost normalized protein sets involved in protein synthesis and immune response, processes linked to the increased susceptibility to cancer and bacterial infections seen in people with RDEB.

CONCLUSIONS

Dysregulated histone acetylation contributes to RDEB pathogenesis by facilitating the progression of fibrosis. Repurposing of HDACi could be considered for disease-modifying treatments in RDEB.

Role of histone deacetylase inhibitors in non-neoplastic diseases

Background

Epigenetic dysregulation has been implicated in the development and progression of a variety of human diseases, but epigenetic changes are reversible, and epigenetic enzymes and regulatory proteins can be targeted using small molecules. Histone deacetylase inhibitors (HDACis), as a class of epigenetic drugs, are widely used to treat various cancers and other diseases involving abnormal gene expression.

Results

Specially, HDACis have emerged as a promising strategy to enhance the therapeutic effect of non-neoplastic conditions, including neurological disorders, cardiovascular diseases, renal diseases, autoimmune diseases, inflammatory diseases, infectious diseases and rare diseases, along with their related mechanisms. However, their clinical efficacy has been limited by drug resistance and toxicity.

Conclusions

To date, most clinical trials of HDAC inhibitors have been related to the treatment of cancer rather than the treatment of non-cancer diseases, for which experimental studies are gradually underway. Discussions regarding non-neoplastic diseases often concentrate on specific disease types. Therefore, this review highlights the development of HDACis and their potential therapeutic applications in non-neoplastic diseases, either as monotherapy or in combination with other drugs or therapies.

Effects of valproic acid on wound healing of the abdominal wall musculoaponeurotic layer: an experimental study in rats

INTRODUCTION

valproic acid (VPA), an epigenetic drug, has potential for the treatment of neoplasms. Its effects on the healing of the peritoneal-musculo-aponeurotic plane (PMA) of the abdominal wall are studied.

METHOD

sixty Wistar rats were allocated into two groups: experimental (VPA) and control (0.9% sodium chloride), treated daily, starting three days before the intervention and until euthanasia. Under anesthesia, a median laparotomy was performed and repaired with two synthetic layers. Assessments took place 3, 7 and 14 days after surgery. The integrity of the wounds, the quality of the inflammatory reaction, the intensity of the leukocyte infiltrate, collagen synthesis, the intensity of angiogenesis and the presence of myofibroblasts were studied.

RESULTS

there was dehiscence of the PMA plane in 11 of the 30 animals (p=0.001) in the experimental group. There was no difference in the quality and intensity of the inflammatory reaction. Immunohistochemistry revealed, in the experimental group, less collagen I (p3=0.003, p7=0.013 and p14=0.001) and more collagen III (p3=0.003, p7=0.013 and p14= 0.001). Collagen evaluated by Sirus Supra Red F3BA showed, in the experimental group, less collagen at all three times (p<0.001) with less collagen I and collagen III (p<0.001). A lower number of vessels was found on the 3rd day (p<0.001) and on the 7th day (p=0.001) and did not affect the number of myofibroblasts.

CONCLUSION

VPA showed dehiscence of the PMA plane, with less deposition of total collagen and collagen I, less angiogenic activity, without interfering with the number of myofibroblasts.

Effects of valproic acid on wound healing of the abdominal wall musculoaponeurotic layer: an experimental study in rats

INTRODUCTION

valproic acid (VPA), an epigenetic drug, has potential for the treatment of neoplasms. Its effects on the healing of the peritoneal-musculo-aponeurotic plane (PMA) of the abdominal wall are studied.

METHOD

sixty Wistar rats were allocated into two groups: experimental (VPA) and control (0.9% sodium chloride), treated daily, starting three days before the intervention and until euthanasia. Under anesthesia, a median laparotomy was performed and repaired with two synthetic layers. Assessments took place 3, 7 and 14 days after surgery. The integrity of the wounds, the quality of the inflammatory reaction, the intensity of the leukocyte infiltrate, collagen synthesis, the intensity of angiogenesis and the presence of myofibroblasts were studied.

RESULTS

there was dehiscence of the PMA plane in 11 of the 30 animals (p=0.001) in the experimental group. There was no difference in the quality and intensity of the inflammatory reaction. Immunohistochemistry revealed, in the experimental group, less collagen I (p3=0.003, p7=0.013 and p14=0.001) and more collagen III (p3=0.003, p7=0.013 and p14= 0.001). Collagen evaluated by Sirus Supra Red F3BA showed, in the experimental group, less collagen at all three times (p<0.001) with less collagen I and collagen III (p<0.001). A lower number of vessels was found on the 3rd day (p<0.001) and on the 7th day (p=0.001) and did not affect the number of myofibroblasts.

CONCLUSION

VPA showed dehiscence of the PMA plane, with less deposition of total collagen and collagen I, less angiogenic activity, without interfering with the number of myofibroblasts.

Transcriptomic profiling of peripheral blood cells in HPV-associated carcinoma patients receiving combined valproic acid and avelumab

Human papillomavirus (HPV)-associated cancer continues to evade the immune system by promoting a suppressive tumor microenvironment. Therefore, immunotherapy appears to be a promising approach for targeting HPV-associated tumors. We hypothesized that valproic acid (VA) as an epigenetic agent combined with avelumab may enhance the antitumor immunity in HPV-associated solid tumors. We performed bulk RNA-sequencing (RNA-Seq) on total peripheral blood mononuclear cells (PBMCs) of seven nonresponders (NRs) and four responders (Rs). A total of 39 samples (e.g., pretreatment, post-VA, postavelumab, and endpoint) were analyzed. Also, we quantified plasma analytes and performed flow cytometry. We observed a differential pattern in immune response following treatment with VA and/or avelumab in NRs vs. Rs. A significant upregulation of transcripts associated with NETosis [the formation of neutrophil extracellular traps (NETs)] and neutrophil degranulation pathways was linked to the presence of a myeloid-derived suppressor cell signature in NRs. We noted the elevation of IL-8/IL-18 cytokines and a distinct transcriptome signature at the baseline and endpoint in NRs. By using the receiver operator characteristics, we identified a cutoff value for the plasma IL-8/IL-18 to discriminate NRs from Rs. We found differential therapeutic effects for VA and avelumab in NRs vs. Rs. Thus, our results imply that measuring the plasma IL-8/IL-18 and bulk RNA-Seq of PBMCs may serve as valuable biomarkers to predict immunotherapy outcomes.

Phase 2 Study of Sorafenib, Valproic Acid, and Sildenafil in the Treatment of Recurrent High-Grade Glioma

Here we report the results of a single-center phase 2 clinical trial combining sorafenib tosylate, valproic acid, and sildenafil for the treatment of patients with recurrent high-grade glioma (NCT01817751). Clinical toxicities were grade 1 and grade 2, with one grade 3 toxicity for maculopapular rash (6.4%). For all evaluable patients, the median progression-free survival was 3.65 months and overall survival (OS) 10.0 months. There was promising evidence showing clinical activity and benefit. In the 33 evaluable patients, low protein levels of the chaperone GRP78 (HSPA5) was significantly associated with a better OS (p < 0.0026). A correlation between the expression of PDGFRα and OS approached significance (p < 0.0728). Five patients presently have a mean OS of 73.6 months and remain alive. This is the first therapeutic intervention glioblastoma trial to significantly associate GRP78 expression to OS. Our data suggest that the combination of sorafenib tosylate, valproic acid, and sildenafil requires additional clinical development in the recurrent glioma population.

Mitochondrial targets in hyperammonemia: Addressing urea cycle function to improve drug therapies

The urea cycle (UC) is a critically important metabolic process for the disposal of nitrogen (ammonia) produced by amino acids catabolism. The impairment of this liver-specific pathway induced either by primary genetic defects or by secondary causes, namely those associated with hepatic disease or drug administration, may result in serious clinical consequences. Urea cycle disorders (UCD) and certain organic acidurias are the major groups of inherited rare diseases manifested with hyperammonemia (HA) with UC dysregulation. Importantly, several commonly prescribed drugs, including antiepileptics in monotherapy or polytherapy from carbamazepine to valproic acid or specific antineoplastic agents such as asparaginase or 5-fluorouracil may be associated with HA by mechanisms not fully elucidated. HA, disclosing an imbalance between ammoniagenesis and ammonia disposal via the UC, can evolve to encephalopathy which may lead to significant morbidity and central nervous system damage. This review will focus on biochemical mechanisms related with HA emphasizing some poorly understood perspectives behind the disruption of the UC and mitochondrial energy metabolism, namely: i) changes in acetyl-CoA or NAD+ levels in subcellular compartments; ii) post-translational modifications of key UC-related enzymes, namely acetylation, potentially affecting their catalytic activity; iii) the mitochondrial sirtuins-mediated role in ureagenesis. Moreover, the main UCD associated with HA will be summarized to highlight the relevance of investigating possible genetic mutations to account for unexpected HA during certain pharmacological therapies. The ammonia-induced effects should be avoided or overcome as part of safer therapeutic strategies to protect patients under treatment with drugs that may be potentially associated with HA.

Valproate modulates the activity of multidrug resistance efflux pumps, as a chemoresistance factor in gastric cancer cells

BACKGROUND

Drug resistance is one of the most critical problems in gastric cancer therapy. This study was performed to investigate the valproic acid effects on the proliferation of sensitive and resistant cell lines of human gastric cancer, and to explore the mechanism of the agent on multi drug resistance and apoptosis genes.

METHODS

The cytotoxicity effect of valproic acid on the EPG85.257 and EPG85.257RDB cells was assessed by the MTT assay, and the IC50 concentration was evaluated. Apoptosis, genotoxicity, and drug resistance pump activity were evaluated using comet assay, Real-time PCR, and flow cytometry, respectively. Cell proliferation was assayed using a scratch test.

RESULTS

Dose-dependent toxicity was recorded after treatment of cells with valproic acid. Valproic acid represented a significant growth inhibition on EPG85.257 cells with IC50 values of 5.84 µM and 4.78 µM after 48 h and 72 h treatment, respectively. In contrast, the drug-resistant counterpart represented 8.7 µM and 7.02 µM IC50 values after the same treatment time. Valproic acid induced PTEN, Bcl2, P53, Bax, P21, and caspase3 expression in EPG85.257 cells, whereas p21, p53, PTEN, and ABCB1 were overexpressed in EPG5.257RDB. Valproic acid hindered cell migration in both cell lines (P < 0.01). Valproate genotoxicity was significantly higher in the parent cells than in their resistant EPG85.257RDB counterparts. Valproate led to a 62% reduction in the daunorubicin efflux of the MDR1 pump activity.

CONCLUSIONS

Valproate can affect drug resistance in gastric cancer via a unique mechanism independent of MDR1 expression.

Epigenetic studies in insects and the valproic acid perspective

Abstract Valproic acid in association with sodium valproate (VPA) is an important anticonvulsant drug used for decades to treat neurological disorders. VPA also acts as an epigenetic modulator by inhibiting histone deacetylases, permitting histone acetylation, affecting the DNA and histone methylation status and gene expression, and inducing chromatin remodeling. Insects represent an important animal model for studies in several areas of science. Their high phenotypic plasticity makes them alternative models for epigenetic studies. This brief review emphasizes recent reports on insect epigenetics and the contribution of studies on the VPA action in insects, including effects on epigenetic markers, extending the pharmacological understanding of the potential of this drug, and demonstrating the usefulness of insects as an alternative animal model to drug studies.

Valproic acid radiosensitizes anaplastic thyroid cells through a decrease of the DNA damage repair capacity

BACKGROUND

Anaplastic thyroid cancer (ATC) represents a rare lethal human malignancy with poor prognosis. Multimodality treatment, including radiotherapy, is recommended to improve local control and survival. Valproic acid (VA) is a clinically available histone deacetylase inhibitor with a well-documented side effect profile. In this study, we aim to investigate the combined effect of VA with photon irradiation in vitro.

METHODS

Anaplastic thyroid cancer cells (8505c) were used to investigate the radiosensitizing effect of VA.

RESULTS

VA sensitized cells to photon irradiation. VA increased radiation-induced apoptosis and radiation-induced DNA damage measured by γH2AX foci induction. Furthermore, VA prolonged γH2AX foci disappearance over time in irradiated cells and decreased the radiation-induced levels of mRNA of key DNA damage repair proteins of the homologous recombination (HR) and the nonhomologous end joining (NHEJ) pathways.

CONCLUSIONS

VA at a clinically safe dose enhance the radiosensitivity of 8505c cells through an increase in radiation-induced apoptosis and a disruption in the molecular mechanism of HR and NHEJ DNA damage repair pathways.

Oncoviruses: How do they hijack their host and current treatment regimes

Viruses have the ability to modulate the cellular machinery of their host to ensure their survival. While humans encounter numerous viruses daily, only a select few can lead to disease progression. Some of these viruses can amplify cancer-related traits, particularly when coupled with factors like immunosuppression and co-carcinogens. The global burden of cancer development resulting from viral infections is approximately 12%, and it arises as an unfortunate consequence of persistent infections that cause chronic inflammation, genomic instability from viral genome integration, and dysregulation of tumor suppressor genes and host oncogenes involved in normal cell growth. This review provides an in-depth discussion of oncoviruses and their strategies for hijacking the host's cellular machinery to induce cancer. It delves into how viral oncogenes drive tumorigenesis by targeting key cell signaling pathways. Additionally, the review discusses current therapeutic approaches that have been approved or are undergoing clinical trials to combat malignancies induced by oncoviruses. Understanding the intricate interactions between viruses and host cells can lead to the development of more effective treatments for virus-induced cancers.

The evidence for repurposing anti-epileptic drugs to target cancer

Antiepileptic drugs are versatile drugs with the potential to be used in functional drug formulations with drug repurposing approaches. In the present review, we investigated the anticancer properties of antiepileptic drugs and interlinked cancer and epileptic pathways. Our focus was primarily on those drugs that have entered clinical trials with positive results and those that provided good results in preclinical studies. Many contributing factors make cancer therapy fail, like drug resistance, tumor heterogeneity, and cost; exploring all alternatives for efficient treatment is important. It is crucial to find new drug targets to find out new antitumor molecules from the already clinically validated and approved drugs utilizing drug repurposing methods. The advancements in genomics, proteomics, and other computational approaches speed up drug repurposing. This review summarizes the potential of antiepileptic drugs in different cancers and tumor progression in the brain. Valproic acid, oxcarbazepine, lacosamide, lamotrigine, and levetiracetam are the drugs that showed potential beneficial outcomes against different cancers. Antiepileptic drugs might be a good option for adjuvant cancer therapy, but there is a need to investigate further their efficacy in cancer therapy clinical trials.

Duality of Valproic Acid Effects on Inflammation, Oxidative Stress and Autophagy in Human Eosinophilic Cells

Eosinophils function in rapid innate immune responses and allergic reactions. Recent research has raised the possibility that the histone deacetylase inhibitor valproic acid (VPA) may be a promising therapeutic agent for treatment of allergic responses and certain cancers. However, its effects on eosinophils remain unclear. Utilizing the EoL-1 human eosinophil cell line as a model, we investigated the effects of VPA on oxidative stress- and autophagy-mediated immune responses. We found that VPA induced reactive oxidative species (ROS) generation and eosinophil activation without affecting cell viability. Moreover, VPA treatment suppressed the negative regulator of antioxidant transcription factor Nrf2, which is known to activate antioxidant defense. Interestingly, VPA was able to increase autophagic markers, as well as NLRP3 and NLRC4 mRNA activation, in Eol-1 cells in a dose-dependent manner. Collectively, our results indicate that VPA could increase the severity of allergic responses, and if so, it clearly would not be a suitable drug for the treatment of allergic reactions. However, VPA does have the potential to induce autophagy and to regulate the inflammatory responses via inflammasome-driven caspase-1 deactivation in a dose-dependent manner.

In situbiosensing technologies for an organ-on-a-chip

Thein vitrosimulation of organs resolves the accuracy, ethical, and cost challenges accompanyingin vivoexperiments. Organoids and organs-on-chips have been developed to model thein vitro, real-time biological and physiological features of organs. Numerous studies have deployed these systems to assess thein vitro, real-time responses of an organ to external stimuli. Particularly, organs-on-chips can be most efficiently employed in pharmaceutical drug development to predict the responses of organs before approving such drugs. Furthermore, multi-organ-on-a-chip systems facilitate the close representations of thein vivoenvironment. In this review, we discuss the biosensing technology that facilitates thein situ, real-time measurements of organ responses as readouts on organ-on-a-chip systems, including multi-organ models. Notably, a human-on-a-chip system integrated with automated multi-sensing will be established by further advancing the development of chips, as well as their assessment techniques.

Nuclear Morphofunctional Organization and Epigenetic Characteristics in Somatic Cells of T. infestans (Klug, 1834)

Triatoma infestans (Klug) is an insect recognized as not only an important vector of South American trypanosomiasis (Chagas disease) but also a model of specific cellular morphofunctional organization and epigenetic characteristics. The purpose of the present review is to highlight certain cellular processes that are particularly unveiled in T. infestans, such as the following: (1) somatic polyploidy involving nuclear and cell fusions that generate giant nuclei; (2) diversification of nuclear phenotypes in the Malpighian tubules during insect development; (3) heterochromatin compartmentalization into large bodies with specific spatial distribution and presumed mobility in the cell nuclei; (4) chromatin remodeling and co-occurrence of necrosis and apoptosis in the Malpighian tubules under stress conditions; (5) epigenetic markers; and (6) response of heterochromatin to valproic acid, an epidrug that inhibits histone deacetylases and induces DNA demethylation in other cell systems. These cellular processes and epigenetic characteristics emphasize the role of T. infestans as an attractive model for cellular research. A limitation of these studies is the availability of insect supply by accredited insectaries. For studies that require the injection of drugs, the operator's dexterity to perform insect manipulation is necessary, especially if young nymphs are used. For studies involving in vitro cultivation of insect organs, the culture medium should be carefully selected to avoid inconsistent results.

Comparison of the probability of four anticonvulsant mood stabilizers to facilitate polycystic ovary syndrome in women with epilepsies or bipolar disorder-A systematic review and meta-analysis

Background

Patients treated with anticonvulsant mood stabilizers have a higher incidence of polycystic ovary syndrome (PCOS). However, there is no comparison between different anticonvulsant mood stabilizers. The purpose of this study was to systematically evaluate the prevalence of PCOS in women taking anticonvulsant mood stabilizers and compare the probability of PCOS caused by different anticonvulsant mood stabilizers.

Methods

Five databases, namely PubMed, Embase, Web of Science, Cochrane Library, and Clinical Trials, were searched for literature on anticonvulsant mood stabilizers and PCOS published up to October 28, 2022. This meta-analysis was performed using Revman 5.4, Stata 14.0, and R4.1.0, and effect size pooling was performed in fixed- or random-effects models based on the results of I² and Q-test, and the surface under the cumulative ranking curve (SUCRA) was used for analysis to assess the cumulative probability of drug-induced PCOS. Publication bias was assessed by funnel plot Egger's test and meta regression.

Results

Twenty studies with a total of 1,524 patients were included in a single-arm analysis, which showed a combined effect size (95% CI) of 0.21 (0.15-0.28) for PCOS in patients taking anticonvulsant mood stabilizers. Nine controlled studies, including 500 patients taking medication and 457 healthy controls, were included in a meta-analysis, which showed OR = 3.23 and 95% CI = 2.19-4.76 for PCOS in women taking anticonvulsant mood stabilizers. Sixteen studies with a total of 1416 patients were included in a network meta-analysis involving four drugs, valproate (VPA), carbamazepine (CBZ), oxcarbazepine (OXC), and lamotrigine (LTG), and the results of the network meta-analysis showed that VPA (OR = 6.86, 95% CI = 2.92-24.07), CBZ (OR = 3.28, 95% CI = 0.99-12.64), OXC (OR = 4.30, 95% CI = 0.40-49.49), and LTG (OR = 1.99, 95% CI = 0.16-10.30), with cumulative probabilities ranked as VPA (90.1%), OXC (63.9%), CBZ (50.1%), and LTG (44.0%).

Conclusion

The incidence of PCOS was higher in female patients treated with anticonvulsant mood stabilizers than in the healthy population, with VPA having the highest likelihood of causing PCOS. The most recommended medication when considering PCOS factors is LTG.

Systematic review registration

identifier: CRD42022380927.

Manganese(ii) complexes stimulate antitumor immunity via aggravating DNA damage and activating the cGAS-STING pathway

Activating the cyclic GMP-AMP synthase-stimulator of the interferon gene (cGAS-STING) pathway is a promising immunotherapeutic strategy for cancer treatment. Manganese(ii) complexes MnPC and MnPVA (P = 1,10-phenanthroline, C = chlorine, and VA = valproic acid) were found to activate the cGAS-STING pathway. The complexes not only damaged DNA, but also inhibited histone deacetylases (HDACs) and poly adenosine diphosphate-ribose polymerase (PARP) to impede the repair of DNA damage, thereby promoting the leakage of DNA fragments into cytoplasm. The DNA fragments activated the cGAS-STING pathway, which initiated an innate immune response and a two-way communication between tumor cells and neighboring immune cells. The activated cGAS-STING further increased the production of type I interferons and secretion of pro-inflammatory cytokines (TNF-α and IL-6), boosting the tumor infiltration of dendritic cells and macrophages, as well as stimulating cytotoxic T cells to kill cancer cells in vitro and in vivo. Owing to the enhanced DNA-damaging ability, MnPC and MnPVA showed more potent immunocompetence and antitumor activity than Mn2+ ions, thus demonstrating great potential as chemoimmunotherapeutic agents for cancer treatment.

HDAC inhibitor HPTA initiates anti-tumor response by CXCL9/10-recruited CXCR3+CD4+T cells against PAHs carcinogenicity

Polycyclic aromatic hydrocarbons (PAHs) exposure in food is closely associated with the occurrence and development of breast cancer, which may attribute to altered immunotoxicity and immune regulation. Currently, cancer immunotherapy aims to promote tumor-specific T cell responses, especially CD4⁺T helper cells (Th) for anti-tumor immunity. The histone deacetylase inhibitors (HDACis) are found to exert an anti-tumor effect by reshaping the tumor immune microenvironment, but the immune regulatory mechanism of HDACis in PAHs-induced breast tumor remains elusive. Here, using established breast cancer models induced by 7,12-dimethylbenz[a]anthracene (DMBA), a potent carcinogenic agent of PAH, the novel HDACi, 2-hexyl-4-pentylene acid (HPTA) exhibited anti-tumor effect by activating T lymphocytes immune function. HPTA recruited CXCR3⁺CD4⁺T cells into chemokines CXCL9/10-enriched tumor sites, the increased secretion of CXCL9/10 was regulated by the NF-κB-mediated pathway. Furthermore, HPTA promoted Th1 differentiation and assisted cytotoxic CD8⁺T cells in the elimination of breast cancer cells. These findings support the proposition of HPTA as a potential therapeutic in the treatment of PAHs-induced carcinogenicity.

Valproate and lithium: Old drugs for new pharmacological approaches in brain tumors?

Beyond its use as an antiepileptic drug, over time valproate has been increasingly used for several other therapeutic applications. Among these, the antineoplastic effects of valproate have been assessed in several in vitro and in vivo preclinical studies, suggesting that this agent significantly inhibits cancer cell proliferation by modulating multiple signaling pathways. During the last years various clinical trials have tried to find out if valproate co-administration could enhance the antineoplastic activity of chemotherapy in glioblastoma patients and in patients suffering from brain metastases, demonstrating that the inclusion of valproate in the therapeutic schedule causes an improved median overall survival in some studies, but not in others. Thus, the effects of the use of concomitant valproate in brain cancer patients are still controversial. Similarly, lithium has been tested as an anticancer drug in several preclinical studies mainly using the unregistered formulation of lithium chloride salts. Although, there are no data showing that the anticancer effects of lithium chloride are superimposable to the registered lithium carbonate, this formulation has shown preclinical activity in glioblastoma and hepatocellular cancers. However, few but interesting clinical trials have been performed with lithium carbonate on a very small number of cancer patients. Based on published data, valproate could represent a potential complementary therapeutic approach to enhance the anticancer activity of brain cancer standard chemotherapy. Same advantageous characteristics are less convincing for lithium carbonate. Therefore, the planning of specific phase III studies is necessary to validate the repositioning of these drugs in present and future oncological research.

PAMAM-G4 protect the N-(2-hydroxyphenyl)-2-propylpentanamide (HO-AAVPA) and maintain its antiproliferative effects on MCF-7

Our work group designed and synthesized a promissory compound N-(2-hydroxyphenyl)-2-propylpentanamide (HO-AAVPA). The HO-AAVPA is a HDAC1 inhibitor and antiproliferative in cancer cell lines. However, HO-AAVPA is poor water solubility and enzymatically metabolized. In this work, the fourth-generation poly(amidoamine) dendrimer (PAMAM-G4) was used as a drug deliver carrier of HO-AAVPA. Moreover, HO-AAVPA and HO-AAVPA-PAMAM complex were submitted to forced degradation studies (heat, acid, base, oxidation and sunlight). Also, the HO-AAVPA-PAMAM-G4 complex was assayed as antiproliferative in a breast cancer cell line (MCF-7). The HO-AAVPA-PAMAM-G4 complex was obtained by docking and experimentally using three pH conditions: acid (pH = 3.0), neutral (pH = 7.0) and basic (pH = 9.0) showing that PAMAM-G4 captureand protect the HO-AAVPA from forced degradation, it is due to sunlight yielded a by-product from HO-AAVPA. In addition, the PAMAM-G4 favored the HO-AAVPA water solubility under basic and neutral pH conditions with significant difference (F_(2,18) = 259.9, p < 0.001) between the slopes of the three conditions being the basic condition which solubilizes the greatest amount of HO-AAVPA. Finally, the HO-AAVPA-PAMAM-G4 complex showed better antiproliferative effects on MCF-7 (IC₅₀ = 75.3 μM) than HO-AAVPA (IC₅₀ = 192 μM). These results evidence that PAMAM-G4 complex improve the biological effects of HO-AAVPA.

Antitumor Potential of Antiepileptic Drugs in Human Glioblastoma: Pharmacological Targets and Clinical Benefits

Glioblastoma (GBM) is characterized by fast-growing cells, genetic and phenotypic heterogeneity, and radio-chemo-therapy resistance, contributing to its dismal prognosis. Various medical comorbidities are associated with the natural history of GBM. The most disabling and greatly affecting patients' quality of life are neurodegeneration, cognitive impairment, and GBM-related epilepsy (GRE). Hallmarks of GBM include molecular intrinsic mediators and pathways, but emerging evidence supports the key role of non-malignant cells within the tumor microenvironment in GBM aggressive behavior. In this context, hyper-excitability of neurons, mediated by glutamatergic and GABAergic imbalance, contributing to GBM growth strengthens the cancer-nervous system crosstalk. Pathogenic mechanisms, clinical features, and pharmacological management of GRE with antiepileptic drugs (AEDs) and their interactions are poorly explored, yet it is a potentially promising field of research in cancer neuroscience. The present review summarizes emerging cooperative mechanisms in oncogenesis and epileptogenesis, focusing on the neuron-to-glioma interface. The main effects and efficacy of selected AEDs used in the management of GRE are discussed in this paper, as well as their potential beneficial activity as antitumor treatment. Overall, although still many unclear processes overlapping in GBM growth and seizure onset need to be elucidated, this review focuses on the intriguing targeting of GBM-neuron mutual interactions to improve the outcome of the so challenging to treat GBM.

Therapeutic and Toxic Effects of Valproic Acid Metabolites

Valproic acid (VPA) and its salts are psychotropic drugs that are widely used in neurological diseases (epilepsy, neuropathic pain, migraine, etc.) and psychiatric disorders (schizophrenia, bipolar affective disorder, addiction diseases, etc.). In addition, the indications for the appointment of valproate have been expanding in recent years in connection with the study of new mechanisms of action of therapeutic and toxic metabolites of VPA in the human body. Thus, VPA is considered a component of disease-modifying therapy for multiple tumors, neurodegenerative diseases (Huntington's disease, Parkinson's disease, Duchenne progressive dystrophy, etc.), and human immunodeficiency syndrome. The metabolism of VPA is complex and continues to be studied. Known pathways of VPA metabolism include: β-oxidation in the tricarboxylic acid cycle (acetylation); oxidation with the participation of cytochrome P-450 isoenzymes (P-oxidation); and glucuronidation. The complex metabolism of VPA explains the diversity of its active and inactive metabolites, which have therapeutic, neutral, or toxic effects. It is known that some active metabolites of VPA may have a stronger clinical effect than VPA itself. These reasons explain the relevance of this narrative review, which summarizes the results of studies of blood (serum, plasma) and urinary metabolites of VPA from the standpoint of the pharmacogenomics and pharmacometabolomics. In addition, a new personalized approach to assessing the cumulative risk of developing VPA-induced adverse reactions is presented and ways for their correction are proposed depending on the patient's pharmacogenetic profile and the level of therapeutic and toxic VPA metabolites in the human body fluids (blood, urine).

Targeting epigenetic regulation for cancer therapy using small molecule inhibitors

Cancer cells display pervasive changes in DNA methylation, disrupted patterns of histone posttranslational modification, chromatin composition or organization and regulatory element activities that alter normal programs of gene expression. It is becoming increasingly clear that disturbances in the epigenome are hallmarks of cancer, which are targetable and represent attractive starting points for drug creation. Remarkable progress has been made in the past decades in discovering and developing epigenetic-based small molecule inhibitors. Recently, epigenetic-targeted agents in hematologic malignancies and solid tumors have been identified and these agents are either in current clinical trials or approved for treatment. However, epigenetic drug applications face many challenges, including low selectivity, poor bioavailability, instability and acquired drug resistance. New multidisciplinary approaches are being designed to overcome these limitations, e.g., applications of machine learning, drug repurposing, high throughput virtual screening technologies, to identify selective compounds with improved stability and better bioavailability. We provide an overview of the key proteins that mediate epigenetic regulation that encompass histone and DNA modifications and discuss effector proteins that affect the organization of chromatin structure and function as well as presently available inhibitors as potential drugs. Current anticancer small-molecule inhibitors targeting epigenetic modified enzymes that have been approved by therapeutic regulatory authorities across the world are highlighted. Many of these are in different stages of clinical evaluation. We also assess emerging strategies for combinatorial approaches of epigenetic drugs with immunotherapy, standard chemotherapy or other classes of agents and advances in the design of novel epigenetic therapies.

Sodium Valproate Modulates the Methylation Status of Lysine Residues 4, 9 and 27 in Histone H3 of HeLa Cells

BACKGROUND

Valproic acid/sodium valproate (VPA), a well-known anti-epileptic agent, inhibits histone deacetylases, induces histone hyperacetylation, promotes DNA demethylation, and affects the histone methylation status in some cell models. Histone methylation profiles have been described as potential markers for cervical cancer prognosis. However, histone methylation markers that can be studied in a cervical cancer cell line, like HeLa cells, have not been investigated following treatment with VPA.

METHODS

In this study, the effect of 0.5 mM and 2.0 mM VPA for 24 h on H3K4me2/me3, H3K9me/me2 and H3K27me/me3 signals as well as on KMT2D, EZH2, and KDM3A gene expression was investigated using confocal microscopy, Western blotting, and RT-PCR. Histone methylation changes were also investigated by Fourier-transform infrared spectroscopy (FTIR).

RESULTS

We found that VPA induces increased levels of H3K4me2/me3 and H3K9me, which are indicative of chromatin activation. Particularly, H3K4me2 markers appeared intensified close to the nuclear periphery, which may suggest their implication in increased transcriptional memory. The abundance of H3K4me2/me3 in the presence of VPA was associated with increased methyltransferase KMT2D gene expression. VPA induced hypomethylation of H3K9me2, which is associated with gene silencing, and concomitant with the demethylase KDM3A, it increased gene expression. Although VPA induces increased H3K27me/me3 levels, it is suggested that the role of the methyltransferase EZH2 in this context could be affected by interactions with this drug.

CONCLUSION

Histone FTIR spectra were not affected by VPA under present experimental conditions. Whether our epigenetic results are consistent with VPA affecting the aggressive tumorous state of HeLa cells, further investigation is required.

Valproic acid attenuates cellular senescence in diabetic kidney disease through the inhibition of complement C5a receptors

Despite increasing knowledge about the factors involved in the progression of diabetic complications, diabetic kidney disease (DKD) continues to be a major health burden. Current therapies only slow but do not prevent the progression of DKD. Thus, there is an urgent need to develop novel therapy to halt the progression of DKD and improve disease prognosis. In our preclinical study where we administered a histone deacetylase (HDAC) inhibitor, valproic acid, to streptozotocin-induced diabetic mice, albuminuria and glomerulosclerosis were attenuated. Furthermore, we discovered that valproic acid attenuated diabetes-induced upregulation of complement C5a receptors, with a concomitant reduction in markers of cellular senescence and senescence-associated secretory phenotype. Interestingly, further examination of mice lacking the C5a receptor 1 (C5aR1) gene revealed that cellular senescence was attenuated in diabetes. Similar results were observed in diabetic mice treated with a C5aR1 inhibitor, PMX53. RNA-sequencing analyses showed that PMX53 significantly regulated genes associated with cell cycle pathways leading to cellular senescence. Collectively, these results for the first time demonstrated that complement C5a mediates cellular senescence in diabetic kidney disease. Cellular senescence has been implicated in the pathogenesis of diabetic kidney disease, thus therapies to inhibit cellular senescence such as complement inhibitors present as a novel therapeutic option to treat diabetic kidney disease.

Cross-reactivity between histone demethylase inhibitor valproic acid and DNA methylation in glioblastoma cell lines

Currently, valproic acid (VPA) is known as an inhibitor of histone deacetylase (epigenetic drug) and is used for the clinical treatment of epileptic events in the course of glioblastoma multiforme (GBM). Which improves the clinical outcome of those patients. We analyzed the level of 5-methylcytosine, a DNA epigenetic modulator, and 8-oxodeoxyguanosine, an cellular oxidative damage marker, affected with VPA administration, alone and in combination with temozolomide (TMZ), of glioma (T98G, U118, U138), other cancer (HeLa), and normal (HaCaT) cell lines. We observed the VPA dose-dependent changes in the total DNA methylation in neoplastic cell lines and the lack of such an effect in a normal cell line. VPA at high concentrations (250-500 μM) induced hypermethylation of DNA in a short time frame. However, the exposition of GBM cells to the combination of VPA and TMZ resulted in DNA hypomethylation. At the same time, we observed an increase of genomic 8-oxo-dG, which as a hydroxyl radical reaction product with guanosine residue in DNA suggests a red-ox imbalance in the cancer cells and radical damage of DNA. Our data show that VPA as an HDAC inhibitor does not induce changes only in histone acetylation, but also changes in the state of DNA modification. It shows cross-reactivity between chromatin remodeling due to histone acetylation and DNA methylation. Finally, total DNA cytosine methylation and guanosine oxidation changes in glioma cell lines under VPA treatment suggest a new epigenetic mechanism of that drug action.

Valproic acid restricts mast cell activation by Listeria monocytogenes

Mast cells (MC) play a central role in the early containment of bacterial infections, such as that caused by Listeria monocytogenes (L.m). The mechanisms of MC activation induced by L.m infection are well known, so it is possible to evaluate whether they are susceptible to targeting and modulation by different drugs. Recent evidence indicates that valproic acid (VPA) inhibits the immune response which favors L.m pathogenesis in vivo. Herein, we examined the immunomodulatory effect of VPA on L.m-mediated MC activation. To this end, bone marrow-derived mast cells (BMMC) were pre-incubated with VPA and then stimulated with L.m. We found that VPA reduced MC degranulation and cytokine release induced by L.m. MC activation during L.m infection relies on Toll-Like Receptor 2 (TLR2) engagement, however VPA treatment did not affect MC TLR2 cell surface expression. Moreover, VPA was able to decrease MC activation by the classic TLR2 ligands, peptidoglycan and lipopeptide Pam3CSK4. VPA also reduced cytokine production in response to Listeriolysin O (LLO), which activates MC by a TLR2-independent mechanism. In addition, VPA decreased the activation of critical events on MC signaling cascades, such as the increase on intracellular Ca²⁺ and phosphorylation of p38, ERK1/2 and -p65 subunit of NF-κB. Altogether, our data demonstrate that VPA affects key cell signaling events that regulate MC activation following L.m infection. These results indicate that VPA can modulate the functional activity of different immune cells that participate in the control of L.m infection.

Changes in uridine 5'-diphospho-glucuronosyltransferase 1A6 expression by histone deacetylase inhibitor valproic acid

Valproic acid (VPA) is well-known as a histone deacetylase (HDAC) inhibitor. It has been reported that HDAC inhibitors enhance basal and aryl hydrocarbon receptor (AhR) ligand-induced aryl hydrocarbon receptor-responsive gene expression. Other studies suggested that HDAC inhibition might significantly activate the NF-E2-related factor-2 (Nrf2). Moreover, VPA activates mitogen-activated protein kinases (MAPKs). MAPK pathways regulate Nrf2 transactivation domain activity. Uridine 5'-diphospho-glucuronosyltransferase (UGT) 1A6 is one of the important isoforms to affect drug pharmacokinetics. UGT1A6 gene is regulated transcriptionally by AhR and Nrf2. The present study aimed to investigate whether UGT1A6 expression was changed by VPA and to elucidate the mechanism of the alteration. Following VPA treatment for 72 h in Caco-2 cells, UGT1A6 mRNA was increased by 7.9-fold. Moreover, UGT1A6 mRNA was increased by other HDAC inhibitors, suggesting that HDAC inhibition caused the UGT1A6 mRNA induction. AhR and Nrf2 proteins in the nucleus of Caco-2 cells were increased by 1.5- and 1.7-fold, respectively, following the VPA treatment. However, VPA treatment did not activate the extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) pathways in Caco-2 cells. In conclusion, we observed that VPA induced UGT1A6 mRNA expression via AhR and Nrf2 pathways, but not via the ERK or JNK pathways.

The effects of valproic acid on skin healing: experimental study in rats

Purpose:

To recognize the effects of valproic acid (VPA), an epigenetic drug, on the skin healing process.

Methods:

Sixty male Wistar rats were divided into two groups: the experiment treated with VPA (100 mg/kg/day); and the control, with 0.9% sodium chloride by gavage. Skin healing was studied in three moments (the third, the seventh, and the 14th day), evaluating the parameters: inflammatory reaction and its intensity (anti-LCA), angiogenesis (anti-CD34), collagen I and III (anti-collagen I, anti-collagen III and Picrosirius-red F3BA) and myofibroblasts (anti-alpha-AMS).

Results:

The inflammatory reaction was acute or sub-acute in both groups on the third day. On the seventh and the 14th day, chronic predominated in the control (p=0.006), and sub-acute in the experiment (p=0.020). There was a greater number of leukocytes in the group treated only on the third day (p=0.036). The number of vessels was lower in the treated group at the three times (p3=0.002, p7<0.001, and p14=0.027). Myofibroblasts were rare in the third day and moderate quantity in the remaining periods. Collagen I density was higher in the control at the three times (p<0.001) and collagen III in the treated group (p<0.001).

Conclusions:

VPA led to a more intense inflammatory reaction, decreased angiogenesis and collagen deposition, especially type I collagen.

Transcriptome meta-analysis of valproic acid exposure in human embryonic stem cells

Valproic acid (VPA) is a widely used antiepileptic drug not recommended in pregnancy because it is teratogenic. Many assays have assessed the impact of the VPA exposure on the transcriptome of human embryonic stem-cells (hESC), but the molecular perturbations that VPA exerts in neurodevelopment are not completely understood. This study aimed to perform a transcriptome meta-analysis of VPA-exposed hESC to elucidate the main biological mechanisms altered by VPA effects on the gene expression. Publicly available microarray and RNA-seq transcriptomes were selected in the Gene Expression Omnibus (GEO) repository. Samples were processed according to the standard pipelines for each technology in the Galaxy server and R. Meta-analysis was performed using the Fisher-P method. Overrepresented genes were obtained by evaluating ontologies, pathways, and phenotypes' databases. The meta-analysis performed in seven datasets resulted in 61 perturbed genes, 54 upregulated. Ontology and pathway enrichments suggested neurodevelopment and neuroinflammatory effects; phenotype overrepresentation included epilepsy-related genes, such as SCN1A and GABRB2. The NDNF gene upregulation was also identified; this gene is involved in neuron migration and survival during development. Sub-network analysis proposed TGFβ and BMP pathways activation. These results suggest VPA exerts effects in epilepsy-related genes even in embryonic cells. Neurodevelopmental genes, such as NDNF were upregulated and VPA might also disturb several development pathways. These mechanisms might help to explain the spectrum of VPA-induced congenital anomalies and the molecular effects on neurodevelopment.

The PRC2 molecule EED is a target of epigenetic therapy for neuroblastoma

Epigenetic modifications by polycomb repressive complex (PRC) molecules appear to play a role in the tumorigenesis and aggressiveness of neuroblastoma (NB). Embryonic ectoderm development (EED) is a member of the PRC2 complex that binds to the H3K27me3 mark deposited by EZH2 via propagation on adjacent nucleosomes. We herein investigated the molecular roles of EED in MYCN-amplified NB cells using EED-knockdown (KD) shRNAs, EED-knockout sgRNAs, and the EED small molecule inhibitor EED226. The suppression of EED markedly inhibited NB cell proliferation and flat and soft agar colony formation. A transcriptome analysis using microarrays of EED-KD NB cells indicated the de-repression of cell cycle-regulated and differentiation-related genes. The results of a GSEA analysis suggested that inhibitory cell cycle-regulated gene sets were markedly up-regulated. Furthermore, an epigenetic treatment with the EED inhibitor EED226 and the HDAC inhibitors valproic acid/SAHA effectively suppressed NB cell proliferation and colony formation. This combined epigenetic treatment up-regulated cell cycle-regulated and differentiation-related genes. The ChIP sequencing analysis of histone codes and PRC molecules suggested an epigenetic background for the de-repression of down-regulated genes in MYCN-amplified/PRC2 up-regulated NB.

Orthotopic Transplantation of Human Paediatric High-Grade Glioma in Zebrafish Larvae

Brain tumours are the most common cause of death among children with solid tumours, and high-grade gliomas (HGG) are among the most devastating forms with very poor outcomes. In the search for more effective treatments for paediatric HGG, there is a need for better experimental models. To date, there are no xenograft zebrafish models developed for human paediatric HGG; existing models rely on adult cells. The use of paediatric models is of great importance since it is well known that the genetic and epigenetic mechanisms behind adult and paediatric disease differ greatly. In this study, we present a clinically relevant in vivo model based on paediatric primary glioma stem cell (GSC) cultures, which after orthotopic injection into the zebrafish larvae, can be monitored using confocal imaging over time. We show that cells invade the brain tissue and can be followed up to 8 days post-injection while they establish in the fore/mid brain. This model offers an in vivo system where tumour invasion can be monitored and drug treatments quickly be evaluated. The possibility to monitor patient-specific cells has the potential to contribute to a better understanding of cellular behaviour and personalised treatments in the future.

Pearls for the diagnosis and possible pathophysiological mechanisms of valproic acid-induced lupus erythematosus: A literature review

Background: Drug-induced lupus erythematosus (DILE) accounts for 10-15% of systemic lupus erythematosus (SLE) cases, with more than 100 pharmaceutical agents implicated in its development. Depending on the offending drug, clinical and serological manifestations present great variability and, thus, DILE may be overlooked in clinical practice. Valproic acid (VPA) - induced lupus erythematosus has not been analytically reported in the literature, rendering the recognition of such cases even more difficult.Objective: The aim of this study was to analyze VPA - induced lupus features and to discuss possible pathophysiological mechanisms.Materials and Methods: This literature review was conducted in PubMed and Embase databases in June 2021, in search of DILE cases induced by VPA. We found 164 manuscripts, out of which 140 articles regarding other adverse effects or drugs were discarded. Finally, 15 cases fulfilled the eligibility criteria to be included in this review.Results: Although SLE is more common in females, VPA-induced lupus presented a male predilection. Patients developed DILE within the first three months of treatment with VPA at a percentage of 50%, whereas four patients from one to five years after VPA initiation. DILE frequently presented with mild symptoms. In most patients, serositis manifested with polyarthritis, pleural effusion or pericarditis. Notably, one patient presented with Rowell's syndrome, a rare subtype of lupus erythematosus with erythema multiforme and speckled pattern of antinuclear antibodies (ANAs). Central nervous system, renal and skin involvement was scarcely observed. Cytopenia was noted in 7 patients. Immunological findings included positive ANAs in the vast majority of the patients (86.7%), positive anti-histone antibodies in five, positive anti-dsDNA antibodies in three and hypocomplementemia in two patients. Despite the prompt resolution of clinical symptoms after VPA discontinuation, serological abnormalities persisted up to 18 months. Apart from the discontinuation of VPA administration for the resolution of DILE, treatment included corticosteroids in 8 cases.Conclusion: Valproic acid has been implicated in several cases of DILE. Clinicians should be aware of this entity and recognize it promptly to ensure a favorable outcome. Possible pathophysiologic associations may be extrapolated, but a clearer understanding of this syndrome is to be gained by further studies.

Valproic acid decreases vascular smooth muscle cell proliferation via protein phosphatase 2A-mediated p70 S6 kinase inhibition

Valproic acid (VPA) has been used to treat epilepsy and bipolar disorder. Although the abnormal proliferation of vascular smooth muscle cells (VSMCs) is a well-established contributor to the development of various vascular diseases including atherosclerosis, the effect of VPA on VSMC proliferation and its mechanism of action have not been fully revealed. Herein, we investigated the molecular mechanism by which VPA inhibits rat VSMC proliferation. VPA dose-dependently decreased VSMC proliferation, which was accompanied by the dose-dependent decrease in phosphorylation of p70 S6 kinase (p70S6K) at Thr389 (p-p70S6K-Thr³⁸⁹), and overexpression of the p70S6K-T389E mutant gene significantly reversed VPA-inhibited VSMC proliferation. Co-treatment with okadaic acid, a specific protein phosphatase 2A (PP2A) inhibitor, significantly restored p-p70S6K-Thr³⁸⁹. Furthermore, knockdown of PP2Ac gene expression by siRNA significantly reversed VPA-inhibited p-p70S6K-Thr³⁸⁹ and VSMC proliferation. Confocal microscopic analyses and co-immunoprecipitation results clearly showed that the physical binding of p70S6K and PP2Ac was promoted by VPA. Valpromide, a VPA's structural derivative with no histone deacetylase (HDAC) inhibition activity, as well as VPA and sodium butyrate, an HDAC inhibitor similar to VPA, decreased VSMC proliferation and p-p70S6K-Thr³⁸⁹, indicating that HDAC is not involved in VPA-inhibited VSMC proliferation. Finally, the inhibitory effects of VPA on p-p70S6K-Thr³⁸⁹ and VSMC proliferation were reiterated in a platelet-derived growth factor (PDGF)-induced in vitro atherosclerosis model. In conclusion, our results demonstrate that VPA decreased cell proliferation via PP2A-mediated inhibition of p-p70S6K-Thr³⁸⁹ in basal and PDGF-stimulated VSMCs. The results suggest that VPA could be used in the treatment and prevention of atherosclerosis and in-stent restenosis.

The Class I HDAC Inhibitor Valproic Acid Strongly Potentiates Gemcitabine Efficacy in Pancreatic Cancer by Immune System Activation

Background: Gemcitabine efficacy in pancreatic cancer is often impaired due to limited intracellular uptake and metabolic activation. Epi-drugs target gene expression patterns and represent a promising approach to reverse chemoresistance. In this study, we investigate the chemosensitizing effect of different epi-drugs when combined with gemcitabine in pancreatic cancer. Methods: Mouse KPC3 cells were used for all experiments. Five different epi-drugs were selected for combination therapy: 5-aza-2′-deoxycytidine, hydralazine, mocetinostat, panobinostat, and valproic acid (VPA). Treatment effects were determined by cell proliferation and colony forming assays. Expression of genes were assessed by real-time quantitative PCR. The most promising epi-drug for combination therapy was studied in immune competent mice. Intratumor changes were defined using NanoString PanCancer panel IO360. Results: All epi-drugs, except hydralazine, potentiated the gemcitabine response in KPC3 cells (range decrease IC50 value 1.7−2-fold; p < 0.001). On colony formation, the cytotoxic effect of 0.5 ng/mL gemcitabine was 1.4 to 6.3 times stronger (p < 0.01). Two out of three drug-transporter genes were strongly upregulated following epi-drug treatment (a range fold increase of 17−124 and 9−60 for Slc28a1 and Slc28a3, respectively; all p < 0.001). VPA combined with gemcitabine significantly reduced tumor size with 74% compared to vehicle-treated mice and upregulated expression of immune-related pathways (range pathway score 0.86−1.3). Conclusions: These results provide a strong rationale for combining gemcitabine with VPA treatment. For the first time, we present intratumor changes and show activation of the immune system. Clinical trials are warranted to assess efficacy and safety of this novel combination in pancreatic cancer patients.

A New Prospect for the Treatment of Nephrotic Syndrome Based on Network Pharmacology Analysis

Network pharmacology is an emerging field which is currently capturing interest in drug discovery and development. Chronic kidney conditions have become a threat globally due to its associated lifelong therapies. Nephrotic syndrome (NS) is a common glomerular disease that is seen in paediatric and adult population with characteristic manifestation of proteinuria, oedema, hypoalbuminemia, and hyperlipidemia. It involves podocyte damage with tubulointerstitial fibrosis and glomerulosclerosis. Till date there has been no specific treatment available for this condition that provides complete remission. Repurposing of drugs can thus be a potential strategy for the treatment of NS. Recently, epigenetic mechanisms were identified that promote progression of many renal diseases. Therefore, in the present study, we investigated two epigenetic drugs valproic acid (VPA) and all-trans retinoic acid (ATRA). Epigenetic drugs act by binging about changes in gene expression without altering the DNA sequence. The changes include DNA methylation or histone modifications. The targets for the two drugs ATRA and VPA were collated from ChEMBL and Binding DB. All the genes associated with NS were collected from DisGeNET and KEGG database. Interacting proteins for the target genes were acquired from STRING database. The genes were then subjected to gene ontology and pathway enrichment analysis using a functional enrichment software tool. A drug-target and drug-potential target-protein interaction network was constructed using the Cytoscape software. Our results revealed that the two drugs VPA and ATRA had 65 common targets that contributed to kidney diseases. Out of which, 25 targets were specifically NS associated. Further, our work exhibited that ATRA and VPA were synergistically involved in pathways of inflammation, renal fibrosis, glomerulosclerosis and possibly mitochondrial biogenesis and endoplasmic reticulum stress. We thus propose a synergistic potential of the two drugs for treating chronic kidney diseases, specifically NS. The outcomes will undoubtedly invigorate further preclinical and clinical explorative studies. We identify network pharmacology as an initial inherent approach in identifying drug candidates for repurposing and synergism.

From natural products to HDAC inhibitors: An overview of drug discovery and design strategy

Histone deacetylases (HDACs) play a key role in the homeostasis of protein acetylation in histones and have recently emerged as a therapeutic target for numerous diseases. The inhibition of HDACs may block angiogenesis, arrest cell growth, and lead to differentiation and apoptosis in tumour cells. Thus, HDAC inhibitors (HDACi) have received increasing attention and many of which are developed from natural sources. In the past few decades, naturally occurring HDACi have been identified to have potent anticancer activities, some of which have demonstrated promising therapeutic effects on haematological malignancies. In this review, we summarized the discovery and modification of HDAC inhibitors from natural sources, novel drug design that uses natural products as parent nuclei, and dual target design strategies that combine HDAC with non-HDAC targets.

Relevant pharmacological interactions between alkylating agents and antiepileptic drugs: Preclinical and clinical data

Seizures are relatively common in cancer patients, and co-administration of chemotherapeutic and antiepileptic drugs (AEDs) is highly probable and necessary in many cases. Nonetheless, clinically relevant interactions between chemotherapeutic drugs and AEDs are rarely summarized and pharmacologically described. These interactions can cause insufficient tumor and seizure control or lead to unforeseen toxicity. This review focused on pharmacokinetic and pharmacodynamic interactions between alkylating agents and AEDs, helping readers to make a rational choice of treatment optimization, and thus improving patients' quality of life. As an example, phenobarbital, phenytoin, and carbamazepine, by increasing the hepatic metabolism of cyclophosphamide, ifosfamide and busulfan, yield smaller peak concentrations and a reduced area under the plasma concentration-time curve (AUC) of the prodrugs; alongside, the maximum concentration and AUC of their active products were increased with the possible onset of severe adverse drug reactions. On the other side, valproic acid, acting as histone deacetylase inhibitor, showed synergistic effects with temozolomide when tested in glioblastoma. The present review is aimed at providing evidence that may offer useful suggestions for rational pharmacological strategies in patients with seizures symptoms undertaking alkylating agents. Firstly, clinicians should avoid the use of enzyme-inducing AEDs in combination with alkylating agents and prefer the use of AEDs, such as levetiracetam, that have a low or no impact on hepatic metabolism. Secondly, a careful therapeutic drug monitoring of both alkylating agents and AEDs (and their active metabolites) is necessary to maintain therapeutic ranges and to avoid serious adverse reactions.

NRF2 activation inhibits valproic acid-induced neural tube defects in mice

Valproic acid (VPA) is a widely prescribed medication that has traditionally been used to treat epilepsy, yet embryonic exposure to VPA increases the risk of the fetus developing neural tube defects (NTDs). While the mechanism by which VPA causes NTDs is unknown, we hypothesize that VPA causes dysmorphogenesis through the disruption of redox-sensitive signaling pathways that are critical for proper embryonic development, and that protection from the redox disruption may decrease the prevalence of NTDs. Time-bred CD-1 mice were treated with 3H-1,2-dithiole-3-thione (D3T), an inducer of nuclear factor erythroid 2-related factor 2 (NRF2)-a transcription factor that activates the intracellular antioxidant response to prevent redox disruptions. Embryos were then collected for whole embryo culture and subsequently treated with VPA in vitro. The glutathione (GSH)/glutathione disulfide (GSSG) redox potential (E_h), a measure of the intracellular redox environment, was measured in the developing mouse embryos. Embryos treated with VPA exhibited a transiently oxidizing GSH/GSSG E_h, while those that received D3T pretreatment prior to VPA exposure showed no differences compared to controls. Moving to an in utero mouse model, time-bred C57BL/6 J dams were pretreated with or without D3T and then exposed to VPA, after which all embryos were collected for morphological analyses. The prevalence of open neural tubes in embryos treated with VPA significantly decreased with D3T pretreatment, as did the severity of the observed defects evaluated by a morphological assessment. These data show that NRF2 induction via D3T pretreatment protects against VPA-induced redox dysregulation and decreases the prevalence of NTDs in developing mouse embryos.

Acute Valproate Exposure Induces Mitochondrial Biogenesis and Autophagy with FOXO3a Modulation in SH-SY5Y Cells

Valproic acid (VPA) is an antiepileptic drug found to induce mitochondrial dysfunction and autophagy in cancer cell lines. We treated the SH-SY5Y cell line with various concentrations of VPA (1, 5, and 10 mM). The treatment decreased cell viability, ATP production, and mitochondrial membrane potential and increased reactive oxygen species production. In addition, the mitochondrial DNA copy number increased after VPA treatment in a dose-dependent manner. Western blotting showed that the levels of mitochondrial biogenesis-related proteins (PGC-1α, TFAM, and COX4) increased, though estrogen-related receptor expression decreased after VPA treatment. Further, VPA treatment increased the total and acetylated FOXO3a protein levels. Although SIRT1 expression was decreased, SIRT3 expression was increased, which regulated FOXO3 acetylation in the mitochondria. Furthermore, VPA treatment induced autophagy via increased LC3-II levels and decreased p62 expression and mTOR phosphorylation. We suggest that VPA treatment induces mitochondrial biogenesis and autophagy via changes in FOXO3a expression and posttranslational modification in the SH-SY5Y cell line.

Combined evaluation of proliferation and apoptosis to calculate IC50 of VPA-induced PANC-1 cells and assessing its effect on the Wnt signaling pathway

Pancreatic ductal adenocarcinoma (PDAC) is among the most deadly cancers. Since most patients develop resistance to conventional treatments, new approaches are in urgency. Valproic acid (VPA) was shown to induce apoptosis and reduce proliferation in PANC-1 cells. Wnt signaling pathway is known to be involved in apoptosis and PDAC onset. However, VPA-induced apoptosis and its impact on Wnt signaling in PDACs are not linked, yet. We aimed to calculate IC₅₀ of VPA-induced PANC-1 cells by combined analyses of proliferation and apoptosis, while assessing its effect on Wnt signaling pathway. PANC-1 was induced with increased VPA doses and time points. Three independent proliferation and apoptosis assays were performed utilizing carboxyfluorescein succinimidyl ester and Annexin V/PI staining, respectively. Flow cytometry measurements were analyzed by CellQuest and NovoExpress. Taqman hydrolysis probes and SYBR Green PCR Mastermix were assessed in expression analyses of Wnt components utilizing 2^-ΔΔCt method. Cell proliferation was inhibited by 50% at 2.5 mM VPA that evoked a significant apoptotic response. Among the screened Wnt components and target genes, only LEF1 exhibited significant four-fold upregulation at this concentration. In conclusion, cancer studies mostly utilize MTT or BrdU assays in estimating cell proliferation and calculating IC₅₀ of drugs, which provided conflicting VPA dosages utilizing PANC-1 cells. Our novel combined approach enabled specific, accurate and reproducible IC₅₀ calculation at single cell basis with no apparent effect on Wnt signaling components. Future studies are needed to clarify the role of LEF1 in this model.

Valproic acid upregulates the expression of the p75NTR/sortilin receptor complex to induce neuronal apoptosis

The antiepileptic and mood stabilizer agent valproic acid (VPA) has been shown to exert anti-tumour effects and to cause neuronal damage in the developing brain through mechanisms not completely understood. In the present study we show that prolonged exposure of SH-SY5Y and LAN-1 human neuroblastoma cells to clinically relevant concentrations of VPA caused a marked induction of the protein and transcript levels of the common neurotrophin receptor p75NTR and its co-receptor sortilin, two promoters of apoptotic cell death in response to proneurotrophins. VPA induction of p75NTR and sortilin was associated with an increase in plasma membrane expression of the receptor proteins and was mimicked by cell treatment with several histone deacetylase (HDAC) inhibitors. VPA and HDAC1 knockdown decreased the level of EZH2, a core component of the polycomb repressive complex 2, and upregulated the transcription factor CASZ1, a positive regulator of p75NTR. CASZ1 knockdown attenuated VPA-induced p75NTR overexpression. Cell treatment with VPA favoured proNGF-induced p75NTR/sortilin interaction and the exposure to proNGF enhanced JNK activation and apoptotic cell death elicited by VPA. Depletion of p75NTR or addition of the sortilin agonist neurotensin to block proNGF/sortilin interaction reduced the apoptotic response to VPA and proNGF. Exposure of mouse cerebellar granule cells to VPA upregulated p75NTR and sortilin and induced apoptosis which was enhanced by proNGF. These results indicate that VPA upregulates p75NTR apoptotic cell signalling through an epigenetic mechanism involving HDAC inhibition and suggest that this effect may contribute to the anti-neuroblastoma and neurotoxic effects of VPA.

Valproic Acid and Breast Cancer: State of the Art in 2021

Valproic acid (2-propylpentanoic acid, VPA) is a short-chain fatty acid, a member of the group of histone deacetylase inhibitors (HDIs). VPA has been successfully used in the treatment of epilepsy, bipolar disorders, and schizophrenia for over 50 years. Numerous in vitro and in vivo pre-clinical studies suggest that this well-known anticonvulsant drug significantly inhibits cancer cell proliferation by modulating multiple signaling pathways. Breast cancer (BC) is the most common malignancy affecting women worldwide. Despite significant progress in the treatment of BC, serious adverse effects, high toxicity to normal cells, and the occurrence of multi-drug resistance (MDR) still limit the effective therapy of BC patients. Thus, new agents which improve the effectiveness of currently used methods, decrease the emergence of MDR, and increase disease-free survival are highly needed. This review focuses on in vitro and in vivo experimental data on VPA, applied individually or in combination with other anti-cancer agents, in the treatment of different histological subtypes of BC.