Phase II trial of domatinostat (4SC-202) in combination with avelumab in patients with previously treated advanced mismatch repair proficient oesophagogastric and colorectal adenocarcinoma: EMERGE.

BACKGROUND: Most oesophagogastric adenocarcinomas (OGAs) and colorectal cancers (CRCs) are mismatch repair proficient (MMRp), responding poorly to immune checkpoint inhibition. We evaluated the safety and efficacy of domatinostat (histone deacetylase inhibitor) plus avelumab (anti-PD-L1 antibody) in patients with previously treated inoperable, advanced/metastatic MMRp OGA and CRC. PATIENTS AND METHODS: Eligible patients were evaluated in a multicentre, open-label dose escalation/dose expansion phase II trial. In the escalation phase, patients received escalating doses of domatinostat [100 mg once daily (OD), 200 mg OD, 200 mg twice daily (BD)] orally for 14 days followed by continuous dosing plus avelumab 10 mg/kg administered intravenously 2-weekly (2qw) to determine the recommended phase II dose (RP2D). The trial expansion phase evaluated the best objective response rate (ORR) during 6 months by RECIST version 1.1 using a Simon two-stage optimal design with 2/9 and 1/10 responses required to proceed to stage 2 in the OGA and CRC cohorts, respectively. RESULTS: Patients (n = 40) were registered between February 2019 and October 2021. Patients in the dose escalation phase (n = 12) were evaluated to confirm the RP2D of domatinostat 200 mg BD plus avelumab 10 mg/kg. No dose-limiting toxicities were observed. Twenty-one patients were treated at the RP2D, 19 (9 OGA and 10 CRC) were assessable for the best ORR; 2 patients with CRC did not receive combination treatment and were not assessable for the primary endpoint analysis. Six patients were evaluated in the dose escalation and expansion phases. In the OGA cohort, the best ORR was 22.2% (95% one-sided confidence interval lower bound 4.1) and the median duration of disease control was 11.3 months (range 9.9-12.7 months). No responses were observed in the CRC cohort. No treatment-related grade 3-4 adverse events were reported at the RP2D. CONCLUSIONS: Responses in the OGA cohort met the criteria to expand to stage 2 of recruitment with an acceptable safety profile. There was insufficient signal in the CRC cohort to progress to stage 2. TRIAL REGISTRATION: NCT03812796 (registered 23rd January 2019).

Acetylation inhibition alleviates energy metabolism in muscles of minipigs varying with the type of muscle fibers.

In this study, we investigated whether preslaughter chemical-induced acetylation affected postmortem energy metabolism and pork quality. Thirty pigs were randomly assigned to control, acetyltransferase inhibitor (ATi) or deacetyltransferase inhibitor treatments. Serum, trapezius, longissimus lumborum, psoas major, semimembranosus and semitendinosus muscles were taken for analyses. The results indicated that ATi treatment significantly reduced the activities of lactate dehydrogenase and creatine kinase and heat shock protein 70 in serum (P < 0.05). ATi treatment increased ATP and glycogen content, but decreased lactic acid content in trapezius, psoas major and semitendinosus muscles (P < 0.05). A total of 13 acetylated proteins bands were identified and the deacetylation of creatine kinase may play a key role in slowing down the postmortem energy metabolism in ATi-treated group. In addition, ATi treatment reduced the rate of postmortem glycolysis in muscles with higher oxidative but lower glycolytic fibers. These findings provide a new insight into the underlying mechanism on muscle-specific postmortem changes of pork quality.

Epigenetic regulation of intestinal peptide transporter PEPT1 as a potential strategy for colorectal cancer sensitization.

Human intestinal peptide transporter PEPT1 is commonly repressed in human colorectal cancer (CRC), yet its relationship with sensitivity to the common CRC treatment ubenimex has not previously been elucidated. In this study, we confirmed PEPT1 suppression in CRC using real-time quantitative polymerase chain reaction and western blotting and then investigated the underlying epigenetic pathways involved using bisulfite sequencing, chromatin immunoprecipitation, siRNA knockdown, and reporter gene assays. We found that PEPT1 transcriptional repression was due to both DNMT1-mediated DNA methylation of the proximal promoter region and HDAC1-mediated histone deacetylation, which blocked P300-mediated H3K18/27Ac at the PEPT1 distal promoter. Finally, the effects of the epigenetic activation of PEPT1 on the CRC response to ubenimex were evaluated using sequential combination therapy of decitabine and ubenimex both in vitro and in xenografts. In conclusion, epigenetic silencing of PEPT1 due to increased DNMT1 and HDAC1 expression plays a vital role in the poor response of CRC to ubenimex.

A randomised evaluation of low-dose cytosine arabinoside (ara-C) plus tosedostat versus low-dose ara-C in older patients with acute myeloid leukaemia: results of the LI-1 trial.

Older patients with acute myeloid leukaemia (AML) account for nearly half of those with the disease. Because they are perceived to be unfit for, unwilling to receive, or unlikely to benefit from conventional chemotherapy they represent an important unmet need. Tosedostat is a selective oral aminopeptidase inhibitor, which in phase I/II trials showed acceptable toxicity and encouraging efficacy. We report the only randomised study of low-dose cytosine arabinoside (LDAC) combined with tosedostat (LDAC-T) versus LDAC in untreated older patients not suitable for intensive treatment. A total of 243 patients were randomised 1:1 as part of the 'Pick-a-Winner' LI-1 trial. There was a statistically non-significant increase in the complete remission (CR) rate with the addition of tosedostat, LDAC-T 19% versus LDAC 12% [odds ratio (OR) 0·61, 95% confidence interval (CI) 0·30-1·23; P = 0·17]. For overall response (CR+CR with incomplete recovery of counts), there was little evidence of a benefit to the addition of tosedostat (25% vs. 18%; OR 0·68, 95% CI 0·37-1·27; P = 0·22). However, overall survival (OS) showed no difference (2-year OS 16% vs. 12%, hazard ratio 0·97, 95% CI 0·73-1·28; P = 0·8). Exploratory analyses failed to identify any subgroup benefitting from tosedostat. Despite promising pre-clinical, early non-randomised clinical data with acceptable toxicity and an improvement in response, we did not find evidence that the addition of tosedostat to LDAC produced a survival benefit in this group of patients with AML. International Standard Randomised Controlled Trial Number: ISRCTN40571019.

Inhibition of human UDP-glucuronosyltransferase enzyme by belinostat: Implications for drug-drug interactions.

Belinostat is a pan-histone deacetylase (HDAC) inhibitor which recently approved for the treatment of relapsed/refractory Peripheral T-cell lymphomas (PTCL). To assess drug-drug interactions (DDIs) potential of belinostat via inhibition of UDP-glucuronosyltransferases (UGTs), the effects of belinostat on UGTs activities were investigated using the non-selective probe substrate 4-methylumbelliferone (4-MU) and trifluoperazine (TFP) by UPLC-MS/MS. Belinostat exhibited a wide range of inhibition against UGTs activities, particularly a potent non-competitive inhibition against UGT1A3, and weak inhibition against UGT1A1, 1A7, 1A8, 2B4 and 2B7. Further, in vitro-in vivo extrapolation (IVIVE) approaches were used to predict the risk of DDI arising from inhibition of UGTs. Our data indicate that the intravenous infusion of belinostat at clinical available dose can contribute a significant increase to the AUC of co-administrated drugs primarily cleared by UGT1A3 or UGT1A1, which will result in potential DDIs. In contrast, oral administrated belinostat is unlikely to cause significant DDIs through inhibition of glucuronidation.

Intravitreal Injection of Liposomes Loaded with a Histone Deacetylase Inhibitor Promotes Retinal Ganglion Cell Survival in a Mouse Model of Optic Nerve Crush.

Various neuroprotective agents have been studied for the treatment of retinal ganglion cell (RGC) diseases, but issues concerning the side effects of systemically administered drugs and the short retention time of intravitreally injected drugs limit their clinical applications. The current study aimed to evaluate the neuroprotective effects of intravitreally injected trichostatin A (TSA)-loaded liposomes in a mouse model of optic nerve crush (ONC) and determine whether TSA-loaded liposomes have therapeutic potential in RGC diseases. The histone deacetylase inhibitor, TSA, was incorporated into polyethylene glycolylated liposomes. C57BL/6J mice were treated with an intravitreal injection of TSA-loaded liposomes and liposomes loaded with a lipophilic fluorescent dye for tracking, immediately after ONC injury. The expression of macroglial and microglial cell markers (glial fibrillary acidic protein and ionized calcium binding adaptor molecule-1), RGC survival, and apoptosis were assessed. We found that the liposomes reached the inner retina. Their fluorescence was detected for up to 10 days after the intravitreal injection, with peak intensity at 3 days postinjection. Intravitreally administered TSA-loaded liposomes significantly decreased reactive gliosis and RGC apoptosis and increased RGC survival in a mouse model of ONC. Our results suggest that TSA-loaded liposomes may help in the treatment of various RGC diseases.

Investigation of molecular mechanisms of experimental compounds in murine models of chronic allergic airways disease using synchrotron Fourier-transform infrared microspectroscopy.

The ovalbumin-induced (OVA) chronic allergic airways murine model is a well-established model for investigating pre-clinical therapies for chronic allergic airways diseases, such as asthma. Here, we examined the effects of several experimental compounds with potential anti-asthmatic effects including resveratrol (RV), relaxin (RLN), L-sulforaphane (LSF), valproic acid (VPA), and trichostatin A (TSA) using both a prevention and reversal model of chronic allergic airways disease. We undertook a novel analytical approach using focal plane array (FPA) and synchrotron Fourier-transform infrared (S-FTIR) microspectroscopic techniques to provide new insights into the mechanisms of action of these experimental compounds. Apart from the typical biological effects, S-FTIR microspectroscopy was able to detect changes in nucleic acids and protein acetylation. Further, we validated the reduction in collagen deposition induced by each experimental compound evaluated. Although this has previously been observed with conventional histological methods, the S-FTIR technique has the advantage of allowing identification of the type of collagen present. More generally, our findings highlight the potential utility of S-FTIR and FPA-FTIR imaging techniques in enabling a better mechanistic understanding of novel asthma therapeutics.

CMH-Small Molecule Docks into SIRT1, Elicits Human IPF-Lung Fibroblast Cell Death, Inhibits Ku70-deacetylation, FLIP and Experimental Pulmonary Fibrosis.

Regenerative capacity in vital organs is limited by fibrosis propensity. Idiopathic pulmonary fibrosis (IPF), a progressive lung disease linked with aging, is a classic example. In this study, we show that in flow cytometry, immunoblots (IB) and in lung sections, FLIP levels can be regulated, in vivo and in vitro, through SIRT1 activity inhibition by CMH (4-(4-Chloro-2-methylphenoxy)-N-hydroxybutanamide), a small molecule that, as we determined here by structural biology calculations, docked into its nonhistone substrate Ku70-binding site. Ku70 immunoprecipitations and immunoblots confirmed our theory that Ku70-deacetylation, Ku70/FLIP complex, myofibroblast resistance to apoptosis, cell survival, and lung fibrosis in bleomycin-treated mice, are reduced and regulated by CMH. Thus, small molecules associated with SIRT1-mediated regulation of Ku70 deacetylation, affecting FLIP stabilization in fibrotic-lung myofibroblasts, may be a useful strategy, enabling tissue regeneration.

Hyaluronidase Coated Molecular Envelope Technology Nanoparticles Enhance Drug Absorption via the Subcutaneous Route.

Parenteral chemotherapy is usually administered intravenously, although patient preference and health economics suggest the subcutaneous (sc) route could be an attractive alternative. However, due to the low aqueous solubility of hydrophobic drugs and injection volume limitations, the total amount of drug that can be administered in a single sc injection is frequently insufficient. We have developed hyaluronidase coated nanoparticles (NPs) that efficiently encapsulate such drugs, thus addressing both issues and allowing sufficient amounts of hydrophobic drug to be administered and absorbed effectively. CUDC-101, a poorly water-soluble multitargeted anticancer drug that simultaneously inhibits the receptor tyrosine kinases (RTKs) EGFR and HER2, as well as histone deacetylase (HDAC), was encapsulated in polymeric Molecular Envelope Technology (MET) NPs. The role of polymer chemistry, formulation parameters, and coating with hyaluronidase (HYD) on MET-CUDC-101 NP formulations was examined and optimized to yield high drug loading and colloidal stability, and, after freeze-drying, stable storage at room temperature for up to 90 days. The pharmacokinetic studies in healthy rats showed that plasma AUC0-24h after sc administration correlates tightly with formulation physical chemistry, specifically in vitro colloidal stability. Compared to uncoated NPs, the HYD-coating doubled the drug plasma exposure. In a murine A431 xenograft model, the coated HYD-MET-CUDC-101 NPs at a dose equivalent to 90 mg kg-1 CUDC-101 increased the survival time from 15 days (control animals treated with hyaluronidase alone) to 43 days. Polymer MET nanoparticles coated with hyaluronidase enabled the subcutaneous delivery of a hydrophobic drug with favorable therapeutic outcomes.

Functional Inhibition of Host Histone Deacetylases (HDACs) Enhances in vitro and in vivo Anti-mycobacterial Activity in Human Macrophages and in Zebrafish.

The rapid and persistent increase of drug-resistant Mycobacterium tuberculosis (Mtb) infections poses increasing global problems in combatting tuberculosis (TB), prompting for the development of alternative strategies including host-directed therapy (HDT). Since Mtb is an intracellular pathogen with a remarkable ability to manipulate host intracellular signaling pathways to escape from host defense, pharmacological reprogramming of the immune system represents a novel, potentially powerful therapeutic strategy that should be effective also against drug-resistant Mtb. Here, we found that host-pathogen interactions in Mtb-infected primary human macrophages affected host epigenetic features by modifying histone deacetylase (HDAC) transcriptomic levels. In addition, broad spectrum inhibition of HDACs enhanced the antimicrobial response of both pro-inflammatory macrophages (Mϕ1) and anti-inflammatory macrophages (Mϕ2), while selective inhibition of class IIa HDACs mainly decreased bacterial outgrowth in Mϕ2. Moreover, chemical inhibition of HDAC activity during differentiation polarized macrophages into a more bactericidal phenotype with a concomitant decrease in the secretion levels of inflammatory cytokines. Importantly, in vivo chemical inhibition of HDAC activity in Mycobacterium marinum-infected zebrafish embryos, a well-characterized animal model for tuberculosis, significantly reduced mycobacterial burden, validating our in vitro findings in primary human macrophages. Collectively, these data identify HDACs as druggable host targets for HDT against intracellular Mtb.

Clonocoprogens A, B and C, new antimalarial coprogens from the Okinawan fungus Clonostachys compactiuscula FKR-0021.

Three new antimalarial compounds, clonocoprogens A, B, and C, were isolated from the static culture of an Okinawan fungus, Clonostachys compactiuscula FKR-0021. These compounds were new analogs of N14-palmitoylcoprogen, reported as a siderophore. They showed moderate antimalarial activity against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains, with IC50 values ranging from 1.7 to 9.9 µM.

Differential effects of HDAC inhibitors on PPN oscillatory activity in vivo.

The pedunculopontine nucleus (PPN) has long been known to be part of the reticular activating system (RAS) in charge of arousal and REM sleep. We previously showed that in vitro exposure to a HDAC Class I and II mixed inhibitor (TSA), or a specific HDAC class IIa inhibitor (MC 1568), decreased PPN gamma oscillations. Given the lack of information on systemic in vivo treatments on neuronal synaptic properties, the present study was designed to investigate the systemic effect of HDAC inhibitors (HDACi) on PPN rhythmicity. Rat pups were injected (acute, single dose) with TSA (4 or 20 mg/kg), MC1568 (4 or 20 mg/kg), or MS275 (20 or 100 mg/kg). Our results show that MC1568 (20 mg/kg) reduced mean frequency of PPN oscillations at gamma band, while increasing mean input resistance (Rm) of PPN neurons. For TSA (4 and 20 mg/kg), we observed reduced mean frequency of oscillations at gamma band and increased mean Rm of PPN neurons. Systemic administration of 20 mg/kg MC1568 and TSA effects on Rm were washed out after 60 min of in vitro incubation of PPN slices, suggesting an underlying functional recovery of PPN calcium-mediated gamma band oscillations over time. In addition, at a lower dose, 4 mg/kg, MC1568 and TSA induced higher mean amplitude gamma oscillations. Blocking HDAC class I might not have deleterious effects on gamma activity, but, more importantly, the inhibition of HDAC class I (at 100 mg/kg) increased gamma band oscillations. In conclusion, the present results in vivo validate our previous findings in vitro and further expand information on the effects of HDAC inhibition on PPN rhythmicity. PPN neurons require normal activity of HDAC class IIa in order to oscillate at gamma band.

Preferential sensitivity to HDAC inhibitors in tumors with CREBBP mutation.

Mutations in the gene encoding for the histone acetyltransferase (HAT) CREBBP are common driver events in multiple types of human cancer, such as small cell lung cancer (SCLC) or Sonic Hedgehog medulloblastoma (SHH MB). Therefore, therapeutic options targeting such alterations are highly desired. We used human cell lines from SCLC as well as primary mouse tumor cells and genetically engineered mouse models for SHH MB to test treatment options with histone deacetylase inhibitors (HDACi) in CREBBP wild-type and mutated tumors. In contrast to CREBBP wild-type SCLC cells, CREBBP-mutated SCLC cells showed significantly lower IC50 values after treatment with HDACi. In addition, both in vitro and in vivo, HDACi had significant effects on cell proliferation of SHH-driven tumor MB cells harboring a CREBBP-mutation as compared to CREBBP wild-type controls. These data suggest that HDACi may serve as an additional therapeutic option for patients suffering from tumors driven by CREBBP mutations.

Combinatorial ixazomib and belinostat therapy induces NFE2L2-dependent apoptosis in Hodgkin and T-cell lymphoma.

Ixazomib activity and transcriptomic analyses previously established in T cell (TCL) and Hodgkin (HL) lymphoma models predicted synergistic activity for histone deacetylase (HDAC) inhibitory combination. In this present study, we determined the mechanistic basis for ixazomib combination with the HDAC inhibitor, belinostat, in HL and TCL cells lines (ixazomib-sensitive/resistant clones) and primary tumour cells. In ixazomib-treated TCL and HL cells, transient inhibition followed by full recovery of proteasomal activity observed was accompanied by induction of proteasomal gene expression with NFE2L2 (also termed NRF2) as a prominent upstream regulator. Downregulation of both NFE2L2 and proteasomal gene expression (validated by quantitative real time polymerase chain reaction) occurred with belinostat treatment in Jurkat and L428 cells. In addition, CRISPR/Cas9 mediated knockdown of NFE2L2 in Jurkat cells resulted in a significant decrease in cell viability with ixazomib compared with untreated control cells. Using transcriptomic and proteasomal activity evaluation of ixazomib, belinostat, or ixazomib + belinostat treated cells, we observed that NFE2L2, proteasome gene expression and functional recovery were abrogated by ixazomib + belinostat combination, resulting in synergistic drug activity in ixazomib-sensitive and -resistant cell lines and primary cells. Altogether, these results suggest that the synergistic activity of ixazomib + belinostat is mediated via inhibition NFE2L2-dependent proteasomal recovery and extended proteasomal inhibition culminating in increased cell death.

Optimization of LpxC Inhibitor Lead Compounds Focusing on Efficacy and Formulation for High Dose Intravenous Administration.

LpxC inhibitors were optimized starting from lead compounds with limited efficacy and solubility and with the goal to provide new options for the treatment of serious infections caused by Gram-negative pathogens in hospital settings. To enable the development of an aqueous formulation for intravenous administration of the drug at high dose, improvements in both solubility and antibacterial activity in vivo were prioritized early on. This lead optimization program resulted in the discovery of compounds such as 13 and 30, which exhibited high solubility and potent efficacy against Gram-negative pathogens in animal infection models.

[Iron deficiency syndromes and their correction with nutritional support in elderly patients with colo-rectal cancer.]

51 patients with operated colorectal cancer T1N0M0, T3N1M0 and T4N0M1 at the age of 67±2,3 years receiving adjuvant chemotherapy and nutritional support (NS) were examined. Nutritional status was assessed using alimentazione-volume diagnosis to the points on L.N.Kostyuchenko, nutritional risk - with NRI, body composition - with bioimpedance method, the iron metabolism - with basic markers (serum ferritin, transferrin saturation with iron, erythrocyte indices: erythrocyte saturation of iron, the average concentration of hemoglobin in the erythrocyte, mean corpuscular volume, hemoglobin, etc.), traditional settings, the staging of tumors - according to TNM. Iron deficiency before the development of anemia can be corrected with NS. Upon the occurrence of anemia requires additional pharmacological treatment iron supplementation, preferable with iron III hydroxide olygoisomaltazat 1000 + NS) for the prevention of toxic-metabolic complications.

Phase I trial of belinostat in combination with 13-cis-retinoic acid in advanced solid tumor malignancies: a California Cancer Consortium NCI/CTEP sponsored trial.

PURPOSE: The reported maximum tolerated dose (MTD) of single-agent belinostat is 1000 mg/m2 given days 1-5, every 21 days. Pre-clinical evidence suggests histone deacetylase inhibitors enhance retinoic acid signaling in a variety of solid tumors. We conducted a phase I study of belinostat combined with 50-100 mg/m2/day 13-cis-retinoic acid (13-cRA) in patients with advanced solid tumors. METHODS: Belinostat was administered days 1-5 and 13-cRA days 1-14, every 21 days. Dose-limiting toxicity (DLT) was defined as cycle 1 hematologic toxicity grade ≥ 3 not resolving to grade ≤ 1 within 1 week or non-hematologic toxicity grade ≥ 3 (except controlled nausea and vomiting and transient liver function abnormalities) attributable to belinostat. RESULTS: Among 51 patients, two DLTs were observed: grade 3 hypersensitivity with dizziness and hypoxia at 1700 mg/m2/day belinostat with 100 mg/m2/day 13-cRA, and grade 3 allergic reaction at 2000 mg/m2/day belinostat with 100 mg/m2/day 13-cRA. The MTD was not reached. Pharmacokinetics of belinostat may be non-linear at high doses. Ten patients had stable disease, including one with neuroendocrine pancreatic cancer for 56 cycles, one with breast cancer for 12 cycles, and one with lung cancer for 8 cycles. Partial responses included a patient with keratinizing squamous cell carcinoma of the tonsils, and a patient with lung cancer. CONCLUSIONS: The combination of belinostat 2000 mg/m2 days 1-5 and 13-cRA 100 mg/m2 days 1-14, every 21 days, was well-tolerated and an MTD was not reached despite doubling the established single-agent MTD of belinostat.

A phase I pharmacokinetic study of belinostat in patients with advanced cancers and varying degrees of liver dysfunction.

AIMS: The histone deacetylase inhibitor belinostat has activity in various cancers. Because belinostat is metabolized by the liver, reduced hepatic clearance could lead to excessive drug accumulation and increased toxicity. Safety data in patients with liver dysfunction are needed for this drug to reach its full potential in the clinic. METHODS: We performed a phase 1 trial to determine the safety, maximum tolerated dose (MTD) and pharmacokinetics of belinostat in patients with advanced cancer and varying degrees of liver dysfunction. RESULTS: Seventy-two patients were enrolled and divided into cohorts based on liver function. In patients with mild dysfunction, the MTD was the same as the recommended phase 2 dose (1000 mg/m2 /day). Belinostat was well tolerated in patients with moderate and severe liver dysfunction, although the trial was closed before the MTD in these cohorts could be determined. The mean clearance of belinostat was 661 mL/min/m2 in patients with normal liver function, compared to 542, 505 and 444 mL/min/m2 in patients with mild, moderate and severe hepatic dysfunction. Although this trial was not designed to assess clinical activity, of the 47 patients evaluable for response, 13 patients (28%) experienced stable disease. CONCLUSION: While a statistically significant difference in clearance indicates increased belinostat exposure with worsening liver function, no relationship was observed between belinostat exposure and toxicity. An assessment of belinostat metabolites revealed significant differences in metabolic pathway capability in patients with differing levels of liver dysfunction. Further studies are needed to establish formal dosing guidelines in this patient population.

Therapeutic strategies to induce ERα in luminal breast cancer to enhance tamoxifen efficacy.

Breast cancer is the most prevalent malignancy and second leading cause of death in women worldwide, with hormone receptor-positive luminal breast cancers being the most widespread subtype. While these tumors are generally amenable to endocrine therapy, cellular heterogeneity and acquired ability of tumor cells to undergo cell state switching makes these populations difficult to be fully targeted and eradicated through conventional methods. We have leveraged a quality-by-design (QbD) approach that integrates biological responses with predictive mathematical modeling to identify key combinations of commercially available drugs to induce estrogen receptor expression for therapeutic targeting. This technology utilizes a high level of automation through a custom-built platform to reduce bias as well as design-of-experiments methodology to minimize the experimental iterations required. Utilizing this approach, we identified a combination of clinical compounds, each at concentrations well below their efficacious dose, able to induce the expression of estrogen receptor alpha (ESR1) in hormone-positive breast cancer cells. Induction of ESR1 in luminal cells leads to chemosensitization. These findings provide proof of concept for the utility of the QbD strategy and identify a unique drug cocktail able to sensitize breast cancer cells to tamoxifen.

Developmental neurotoxicity in the context of multiple sevoflurane exposures: Potential role of histone deacetylase 6.

Animal studies have demonstrated that multiple exposures to sevoflurane during the postnatal period lead to impaired synaptogenesis and cognitive deficits in adulthood. However, the underlying mechanisms remain unclear. Histone deacetylase 6 (HDAC6), a unique isoform of class II histone deacetylases (HDACs), mediates diverse cellular processes such as cell survival, inflammation, intracellular trafficking and protein degradation. Varieties of literature suggest the importance of HDAC6 in memory formation and abnormal neurodegenerative diseases. The aim of this study was to investigate potential roles of HDAC6 in sevoflurane-induced developmental neurotoxicity. Postnatal day 7 (P7) rat pups were randomly assigned to control group and sevoflurane group (n = 6 for each group). They were exposed to 60% oxygen and 40% nitrogen with or without 3% sevoflurane for 2 h daily for three consecutive days (P7, P8 and P9). Immediately after the last exposure, both hippocampi were harvested for detection of HDAC6 expression and activity. Next, P7 rat pups were divided into control group, sevoflurane group, sevoflurane + Tubastatin A, and Tubastatin A groups (n = 6 for each group in molecular experiments; n = 16 for each group in behavioral testing). A dose of 25 mg/kg body weight of Tubastatin A (a selective HDAC6 inhibitor) were administrated intraperitoneally 30 min prior to each sevoflurane exposure. After treatments, expression levels of synaptophysin and postsynaptic density 95 protein (PSD95) were quantified using Western blot, and synaptic ultrastructure was evaluated by transmission electron microscopy. Additional pups were raised until P49 to measure cognitive performance using the Morris water maze test. Our results demonstrated that multiple sevoflurane exposures enhanced HDAC6 expression and activity in hippocampi of the developing brain. Tubastatin A ameliorated sevoflurane-induced decreases in synaptophysin and PSD95 expression during development, as well as synaptic ultrastructural damage and cognitive deficits in adulthood. In conclusion, HDAC6 is involved in the developmental neurotoxicity caused by multiple sevoflurane exposures and its inhibition may prevent related damage.