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PloS One 2018Alpha-hemoglobin stabilizing protein (AHSP) is a molecular chaperone that can reduce the damage caused by excess free α-globin to erythroid cells in patients with...
Alpha-hemoglobin stabilizing protein (AHSP) is a molecular chaperone that can reduce the damage caused by excess free α-globin to erythroid cells in patients with impaired β-globin chain synthesis. We assessed the effect of sodium phenylbutyrate and sodium valproate, two histone deacetylase inhibitors (HDIs) that are being studied for the treatment of hemoglobinopathies, on the expression of AHSP, BCL11A (all isoforms), γ-globin genes (HBG1/2), and some related transcription factors including GATA1, NFE2, EKLF, KLF4, and STAT3. For this purpose, the K562 cell line was cultured for 2, 4, and 6 days in the presence and absence of sodium phenylbutyrate and sodium valproate. Relative real-time qRT-PCR analysis of mRNA levels was performed to determine the effects of the two compounds on gene expression. Expression of all target mRNAs increased significantly (p < 0.05), except for the expression of BCL11A, which was down-regulated (p < 0.05) in the cells treated with both compounds relative to the levels measured for untreated cells. The findings indicated that sodium valproate had a more considerable effect than sodium phenylbutyrate (p < 0.0005) on BCL11A repression and the up-regulation of other studied genes. γ-Globin and AHSP gene expression continuously increased during the culture period in the treated cells, with the highest gene expression observed for 1 mM sodium valproate after 6 days. Both compounds repressed the expression of BCL11A (-XL, -L, -S) and up-regulated GATA1, NFE2, EKLF, KLF4, STAT3, AHSP, and γ-globin genes expression. Moreover, sodium valproate showed a stronger effect on repressing BCL11A and escalating the expression of other target genes. The findings of this in vitro experiment could be considered in selecting drugs for clinical use in patients with β-hemoglobinopathies.
Topics: Blood Proteins; Gene Expression Regulation; Hemoglobinopathies; Histone Deacetylase Inhibitors; Humans; K562 Cells; Kruppel-Like Factor 4; Molecular Chaperones; Phenylbutyrates; Real-Time Polymerase Chain Reaction; Valproic Acid
PubMed: 29389946
DOI: 10.1371/journal.pone.0189267 -
Molecular Cancer Mar 2008Cisplatin has been widely used to treat head and neck cancer. One of the clinical limitations with this treatment, however, is that tumors that are initially responsive...
BACKGROUND
Cisplatin has been widely used to treat head and neck cancer. One of the clinical limitations with this treatment, however, is that tumors that are initially responsive to cisplatin later acquire resistance. We have recently shown that a subset of head and neck cancer cell lines has a defective Fanconi anemia DNA damage response pathway and this defect correlates to cisplatin sensitivity. We have also shown that the histone deacetylase inhibitor phenylbutyrate sensitize human cells to cisplatin. In this study we explored whether phenylbutyrate may sensitize head and neck cancer cells by interfering with the Fanconi anemia pathway.
RESULTS
We found that the phenylbutyrate sensitizes head and neck cancer cell lines to cisplatin. This sensitization by phenylbutyrate correlated to a significant decrease in the formation of cisplatin-induced FANCD2 nuclear foci, which is a functional read out of the Fanconi anemia and BRCA (FA/BRCA) pathway. This abrogation of the FA/BRCA pathway by phenylbutyrate was not due to loss of FANCD2 monoubiquitylation but rather correlated to a phenylbutyrate-mediated reduction in the expression of the BRCA1 protein. Furthermore, we found that cancer cells defective in the FA pathway were also sensitized to cisplatin by phenylbutyrate suggesting that phenylbutyrate targets additional pathways.
CONCLUSION
The results from this study suggest that phenylbutyrate may have therapeutic utility as a cisplatin sensitizer in head and neck cancer by inhibiting the FA/BRCA pathway through the down regulation of BRCA1 as well as by an FA/BRCA-independent mechanism.
Topics: Antineoplastic Combined Chemotherapy Protocols; BRCA1 Protein; Cisplatin; Fanconi Anemia Complementation Group D2 Protein; Head and Neck Neoplasms; Humans; Phenylbutyrates; Signal Transduction; Tumor Cells, Cultured
PubMed: 18325101
DOI: 10.1186/1476-4598-7-24 -
Clinical Cancer Research : An Official... Apr 2021Nicotinamide phosphoribosyltransferase (NAMPT) inhibitors (NAMPTi) are currently in development, but may be limited as single-agent therapy due to compound-specific...
PURPOSE
Nicotinamide phosphoribosyltransferase (NAMPT) inhibitors (NAMPTi) are currently in development, but may be limited as single-agent therapy due to compound-specific toxicity and cancer metabolic plasticity allowing resistance development. To potentially lower the doses of NAMPTis required for therapeutic benefit against acute myeloid leukemia (AML), we performed a genome-wide CRISPRi screen to identify rational disease-specific partners for a novel NAMPTi, KPT-9274.
EXPERIMENTAL DESIGN
Cell lines and primary cells were analyzed for cell viability, self-renewal, and responses at RNA and protein levels with loss-of-function approaches and pharmacologic treatments. efficacy of combination therapy was evaluated with a xenograft model.
RESULTS
We identified two histone deacetylases (HDAC), and , whose knockout conferred synthetic lethality with KPT-9274 in AML. Furthermore, HDAC8-specific inhibitor, PCI-34051, or clinical class I HDAC inhibitor, AR-42, in combination with KPT-9274, synergistically decreased the survival of AML cells in a dose-dependent manner. AR-42/KPT-9274 cotreatment attenuated colony-forming potentials of patient cells while sparing healthy hematopoietic cells. Importantly, combined therapy demonstrated promising efficacy compared with KPT-9274 or AR-42 monotherapy. Mechanistically, genetic inhibition of SIRT6 potentiated the effect of KPT-9274 on PARP-1 suppression by abolishing mono-ADP ribosylation. AR-42/KPT-9274 cotreatment resulted in synergistic attenuation of homologous recombination and nonhomologous end joining pathways in cell lines and leukemia-initiating cells.
CONCLUSIONS
Our findings provide evidence that HDAC8 inhibition- or shSIRT6-induced DNA repair deficiencies are potently synergistic with NAMPT targeting, with minimal toxicity toward normal cells, providing a rationale for a novel-novel combination-based treatment for AML.
Topics: Acrylamides; Aminopyridines; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Cytokines; DNA Damage; DNA End-Joining Repair; Drug Resistance, Neoplasm; Gene Knockout Techniques; Histone Deacetylases; Humans; Hydroxamic Acids; Indoles; Leukemia, Myeloid, Acute; Male; Mice; Nicotinamide Phosphoribosyltransferase; Phenylbutyrates; Recombinational DNA Repair; Repressor Proteins; Sirtuins; Xenograft Model Antitumor Assays
PubMed: 33542077
DOI: 10.1158/1078-0432.CCR-20-3724 -
Journal of Veterinary Internal Medicine May 2019Hyperammonemia can result in hepatic encephalopathy, which in severe cases eventually can lead to coma and death. In dogs, congenital portosystemic shunts (CPSS) are the...
BACKGROUND
Hyperammonemia can result in hepatic encephalopathy, which in severe cases eventually can lead to coma and death. In dogs, congenital portosystemic shunts (CPSS) are the most common cause for hyperammonemia. Conservative treatment consists of a protein modified diet, nonabsorbable disaccharides, antibiotics, or some combinations of these. Sodium benzoate (SB) and sodium phenylbutyrate (SPB) both are used in the acute and long-term treatment of humans with hyperammonemia caused by urea cycle enzyme deficiencies. Both treatments are believed to lower blood ammonia concentrations by promoting excretion of excess nitrogen via alternative pathways.
OBJECTIVES
To evaluate the efficacy and safety of PO treatment with SB and SPB on hyperammonemia and clinical signs in CPSS dogs.
METHODS
Randomized, double-blind, placebo-controlled crossover trial. Concentrations of blood ammonia and bile acids were measured in CPSS dogs before and after a 5-day treatment with SB, SPB, and placebo. A wash-out period of 3 days was used between treatments. A standard questionnaire was developed and distributed to owners to evaluate clinical signs before and after each treatment.
RESULTS
Blood ammonia concentrations were not influenced by any of the treatments and were comparable to those observed during placebo treatment. In addition, SB and SPB treatment did not result in improvement of clinical signs. Adverse effects during treatment included anorexia, vomiting, and lethargy.
CONCLUSIONS AND CLINICAL IMPORTANCE
Based on our results, we conclude that SB or SPB are not useful in the conservative treatment of hyperammonemia in dogs with CPSS.
Topics: Ammonia; Animals; Bile Acids and Salts; Cross-Over Studies; Dogs; Double-Blind Method; Female; Hyperammonemia; Male; Phenylbutyrates; Portal Vein; Random Allocation; Sodium Benzoate; Vascular Malformations
PubMed: 30916412
DOI: 10.1111/jvim.15477 -
Life Science Alliance Apr 2022The human Sec61 complex is a widely distributed and abundant molecular machine. It resides in the membrane of the endoplasmic reticulum to channel two types of cargo:...
The human Sec61 complex is a widely distributed and abundant molecular machine. It resides in the membrane of the endoplasmic reticulum to channel two types of cargo: protein substrates and calcium ions. The gene encodes for the pore-forming Sec61α subunit of the Sec61 complex. Despite their ubiquitous expression, the idiopathic missense mutations p.V67G and p.T185A trigger a localized disease pattern diagnosed as autosomal dominant tubulointerstitial kidney disease (ADTKD-). Using cellular disease models for ADTKD-, we identified an impaired protein transport of the renal secretory protein renin and a reduced abundance of regulatory calcium transporters, including SERCA2. Treatment with the molecular chaperone phenylbutyrate reversed the defective protein transport of renin and the imbalanced calcium homeostasis. Signal peptide substitution experiments pointed at targeting sequences as the cause for the substrate-specific impairment of protein transport in the presence of the V67G or T185A mutations. Similarly, dominant mutations in the signal peptide of renin also cause ADTKD and point to impaired transport of this renal hormone as important pathogenic feature for ADTKD- patients as well.
Topics: Calcium; Endoplasmic Reticulum; HEK293 Cells; Humans; Kidney Diseases; Molecular Chaperones; Mutation, Missense; Phenylbutyrates; Polycystic Kidney Diseases; Protein Transport; Renin; SEC Translocation Channels; Sarcoplasmic Reticulum Calcium-Transporting ATPases
PubMed: 35064074
DOI: 10.26508/lsa.202101150 -
Annals of Hepatology 2014A limited number of medications are typically considered for the management of hepatic encephalopathy occurring as a complication of transjugular intrahepatic... (Review)
Review
A limited number of medications are typically considered for the management of hepatic encephalopathy occurring as a complication of transjugular intrahepatic portosystemic shunt (TIPS) placement. Multiple alternative compounds aimed at disrupting ammoniagenesis are or will soon be available, though their use tends to be limited by a lack of large data sets and of clinical awareness. In this review, we provide a targeted overview of the mechanisms and availability of five anti-ammoniagenic compounds (sodium phenylbutyrate, glycerol phenylbutyrate, sodium benzoate, L-ornithine L-aspartate, and ornithine phenylacetate) identified as possibly useful alternative therapeutic agents for cirrhotic encephalopathy. Three of these medications have been FDA approved for use in congenital urea cycle disorders only, while two are under active investigation for use in cirrhotic patients. In spite of limitations posed by cost and comorbidities, familiarity with these options may prove beneficial in cases refractory to conventional management.
Topics: Ammonia; Benzoates; Comorbidity; Health Care Costs; Hepatic Encephalopathy; Humans; Hypertension, Portal; Phenylacetates; Phenylbutyrates; Portasystemic Shunt, Transjugular Intrahepatic; Treatment Outcome
PubMed: 24552859
DOI: No ID Found -
Hepatology (Baltimore, Md.) Jun 2010Phenylbutyric acid (PBA), which is approved for treatment of urea cycle disorders (UCDs) as sodium phenylbutyrate (NaPBA), mediates waste nitrogen excretion via... (Randomized Controlled Trial)
Randomized Controlled Trial
UNLABELLED
Phenylbutyric acid (PBA), which is approved for treatment of urea cycle disorders (UCDs) as sodium phenylbutyrate (NaPBA), mediates waste nitrogen excretion via combination of PBA-derived phenylacetic acid with glutamine to form phenylactylglutamine (PAGN) that is excreted in urine. Glycerol phenylbutyrate (GPB), a liquid triglyceride pro-drug of PBA, containing no sodium and having favorable palatability, is being studied for treatment of hepatic encephalopathy (HE). In vitro and clinical studies have been performed to assess GPB digestion, safety, and pharmacology in healthy adults and individuals with cirrhosis. GPB hydrolysis was measured in vitro by way of pH titration. Twenty-four healthy adults underwent single-dose administration of GPB and NaPBA and eight healthy adults and 24 cirrhotic subjects underwent single-day and multiple-day dosing of GPB, with metabolites measured in blood and urine. Simulations were performed to assess GPB dosing at higher levels. GPB was hydrolyzed by human pancreatic triglyceride lipase, pancreatic lipase-related protein 2, and carboxyl-ester lipase. Clinical safety was satisfactory. Compared with NaPBA, peak metabolite blood levels with GPB occurred later and were lower; urinary PAGN excretion was similar but took longer. Steady state was achieved within 4 days for both NaPBA and GPB; intact GPB was not detected in blood or urine. Cirrhotic subjects converted GPB to PAGN similarly to healthy adults. Simulations suggest that GPB can be administered safely to cirrhotic subjects at levels equivalent to the highest approved NaPBA dose for UCDs.
CONCLUSION
GPB exhibits delayed release characteristics, presumably reflecting gradual PBA release by pancreatic lipases, and is well tolerated in adults with cirrhosis, suggesting that further clinical testing for HE is warranted.
Topics: Adult; Cross-Over Studies; Female; Glutamine; Humans; Hydrolysis; Lipase; Liver Cirrhosis; Male; Monte Carlo Method; Phenylbutyrates; Urea Cycle Disorders, Inborn
PubMed: 20512995
DOI: 10.1002/hep.23589 -
Nutrients Jul 2019Dysbiosis and a dysregulated gut immune barrier function contributes to chronic immune activation in HIV-1 infection. We investigated if nutritional supplementation with... (Randomized Controlled Trial)
Randomized Controlled Trial
Dysbiosis and a dysregulated gut immune barrier function contributes to chronic immune activation in HIV-1 infection. We investigated if nutritional supplementation with vitamin D and phenylbutyrate could improve gut-derived inflammation, selected microbial metabolites, and composition of the gut microbiota. Treatment-naïve HIV-1-infected individuals ( = 167) were included from a double-blind, randomized, and placebo-controlled trial of daily 5000 IU vitamin D and 500 mg phenylbutyrate for 16 weeks (Clinicaltrials.gov NCT01702974). Baseline and per-protocol plasma samples at week 16 were analysed for soluble CD14, the antimicrobial peptide LL-37, kynurenine/tryptophan-ratio, TMAO, choline, and betaine. Assessment of the gut microbiota involved 16S rRNA gene sequencing of colonic biopsies. Vitamin D + phenylbutyrate treatment significantly increased 25-hydroxyvitamin D levels ( < 0.001) but had no effects on sCD14, the kynurenine/tryptophan-ratio, TMAO, or choline levels. Subgroup-analyses of vitamin D insufficient subjects demonstrated a significant increase of LL-37 in the treatment group ( = 0.02), whereas treatment failed to significantly impact LL-37-levels in multiple regression analysis. Further, no effects on the microbiota was found in number of operational taxonomic units ( = 0.71), Shannon microbial diversity index ( = 0.82), or in principal component analyses ( = 0.83). Nutritional supplementation with vitamin D + phenylbutyrate did not modulate gut-derived inflammatory markers or microbial composition in treatment-naïve HIV-1 individuals with active viral replication.
Topics: Adult; Anti-HIV Agents; Dietary Supplements; Double-Blind Method; Female; Gastrointestinal Microbiome; HIV Infections; HIV-1; Humans; Immunity, Innate; Male; Middle Aged; Phenylbutyrates; Vitamin D; Young Adult
PubMed: 31330899
DOI: 10.3390/nu11071675 -
Journal of Clinical Pharmacology Jul 2013Sodium phenylbutyrate and glycerol phenylbutyrate mediate waste nitrogen excretion in the form of urinary phenylacetylglutamine (PAGN) in patients with urea cycle...
Population pharmacokinetic modeling and dosing simulations of nitrogen-scavenging compounds: disposition of glycerol phenylbutyrate and sodium phenylbutyrate in adult and pediatric patients with urea cycle disorders.
Sodium phenylbutyrate and glycerol phenylbutyrate mediate waste nitrogen excretion in the form of urinary phenylacetylglutamine (PAGN) in patients with urea cycle disorders (UCDs); rare genetic disorders characterized by impaired urea synthesis and hyperammonemia. Sodium phenylbutyrate is approved for UCD treatment; the development of glycerol phenylbutyrate afforded the opportunity to characterize the pharmacokinetics (PK) of both compounds. A population PK model was developed using data from four Phase II/III trials that collectively enrolled patients ages 2 months to 72 years. Dose simulations were performed with particular attention to phenylacetic acid (PAA), which has been associated with adverse events in non-UCD populations. The final model described metabolite levels in plasma and urine for both drugs and was characterized by (a) partial presystemic metabolism of phenylbutyric acid (PBA) to PAA and/or PAGN, (b) slower PBA absorption and greater presystemic conversion with glycerol phenylbutyrate, (c) similar systemic disposition with saturable conversion of PAA to PAGN for both drugs, and (d) body surface area (BSA) as a significant covariate accounting for age-related PK differences. Dose simulations demonstrated similar PAA exposure following mole-equivalent PBA dosing of both drugs and greater PAA exposure in younger patients based on BSA.
Topics: Adult; Child; Child, Preschool; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Computer Simulation; Female; Glutamine; Glycerol; Humans; Male; Models, Biological; Nitrogen; Phenylbutyrates; Randomized Controlled Trials as Topic; Rare Diseases; Urea Cycle Disorders, Inborn
PubMed: 23775211
DOI: 10.1002/jcph.92 -
Scientific Reports Jun 2021Amyloid deposits in pancreatic islets, mainly formed by human islet amyloid polypeptide (hIAPP) aggregation, have been associated with loss of β-cell mass and function,...
Amyloid deposits in pancreatic islets, mainly formed by human islet amyloid polypeptide (hIAPP) aggregation, have been associated with loss of β-cell mass and function, and are a pathological hallmark of type 2 diabetes (T2D). Treatment with chaperones has been associated with a decrease in endoplasmic reticulum stress leading to improved glucose metabolism. The aim of this work was to investigate whether the chemical chaperone 4-phenylbutyrate (PBA) prevents glucose metabolism abnormalities and amyloid deposition in obese agouti viable yellow (A) mice that overexpress hIAPP in β cells (A hIAPP mice), which exhibit overt diabetes. Oral PBA treatment started at 8 weeks of age, when A hIAPP mice already presented fasting hyperglycemia, glucose intolerance, and impaired insulin secretion. PBA treatment strongly reduced the severe hyperglycemia observed in obese A hIAPP mice in fasting and fed conditions throughout the study. This effect was paralleled by a decrease in hyperinsulinemia. Importantly, PBA treatment reduced the prevalence and the severity of islet amyloid deposition in A hIAPP mice. Collectively, these results show that PBA treatment elicits a marked reduction of hyperglycemia and reduces amyloid deposits in obese and diabetic mice, highlighting the potential of chaperones for T2D treatment.
Topics: Amyloid; Animals; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Female; Glucose Intolerance; Glucose Tolerance Test; Homeostasis; Hyperglycemia; Insulin Secretion; Insulin-Secreting Cells; Islet Amyloid Polypeptide; Islets of Langerhans; Male; Mice; Mice, Transgenic; Obesity; Phenylbutyrates
PubMed: 34088954
DOI: 10.1038/s41598-021-91311-2