Displaying publications 21 - 25 of 25 in total

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  1. Alhuthali HM, Bradshaw TD, Lim KH, Kam TS, Seedhouse CH
    BMC Cancer, 2020 Jul 07;20(1):629.
    PMID: 32635894 DOI: 10.1186/s12885-020-07119-2
    BACKGROUND: Acute myeloid leukemia (AML) is a heterogenous hematological malignancy with poor long-term survival. New drugs which improve the outcome of AML patients are urgently required. In this work, the activity and mechanism of action of the cytotoxic indole alkaloid Jerantinine B (JB), was examined in AML cells.

    METHODS: We used a combination of proliferation and apoptosis assays to assess the effect of JB on AML cell lines and patient samples, with BH3 profiling being performed to identify early effects of the drug (4 h). Phosphokinase arrays were adopted to identify potential driver proteins in the cellular response to JB, the results of which were confirmed and extended using western blotting and inhibitor assays and measuring levels of reactive oxygen species.

    RESULTS: AML cell growth was significantly impaired following JB exposure in a dose-dependent manner; potent colony inhibition of primary patient cells was also observed. An apoptotic mode of death was demonstrated using Annexin V and upregulation of apoptotic biomarkers (active caspase 3 and cleaved PARP). Using BH3 profiling, JB was shown to prime cells to apoptosis at an early time point (4 h) and phospho-kinase arrays demonstrated this to be associated with a strong upregulation and activation of both total and phosphorylated c-Jun (S63). The mechanism of c-Jun activation was probed and significant induction of reactive oxygen species (ROS) was demonstrated which resulted in an increase in the DNA damage response marker γH2AX. This was further verified by the loss of JB-induced C-Jun activation and maintenance of cell viability when using the ROS scavenger N-acetyl-L-cysteine (NAC).

    CONCLUSIONS: This work provides the first evidence of cytotoxicity of JB against AML cells and identifies ROS-induced c-Jun activation as the major mechanism of action.

    Matched MeSH terms: Acetylcysteine/pharmacology
  2. Dear JW, Ng ML, Bateman DN, Leroy Sivappiragasam P, Choi H, Khoo BBJ, et al.
    Clin Transl Sci, 2021 Jul;14(4):1476-1489.
    PMID: 33742775 DOI: 10.1111/cts.13009
    N-acetylcysteine (NAC) is an antidote to prevent acetaminophen (paracetamol-APAP)-induced acute liver injury (ALI). The 3-bag licensed 20.25 h standard regimen, and a 12 h modified regimen, are used to treat APAP overdose. This study evaluated the redox thiol response and APAP metabolites, in patients with a single APAP overdose treated with either the 20.25 h standard or 12 h modified regimen. We used liquid chromatography tandem mass spectrometry to quantify clinically important oxidative stress biomarkers and APAP metabolites in plasma samples from 45 patients who participated in a randomized controlled trial (SNAP trial). We investigated the time course response of plasma metabolites at predose, 12 h, and 20.25 h post-start of NAC infusion. The results showed that the 12 h modified regimen resulted in a significant elevation of plasma NAC and cysteine concentrations at 12 h post-infusion. We found no significant alteration in the metabolism of APAP, mitochondrial, amino acids, and other thiol biomarkers with the two regimens. We examined APAP and purine metabolism in overdose patients who developed ALI. We showed the major APAP-metabolites and xanthine were significantly higher in patients with ALI. These biomarkers correlated well with alanine aminotransferase activity at admission. Receiver operating characteristic analysis showed that at admission, plasma APAP-metabolites and xanthine concentrations were predictive for ALI. In conclusion, a significantly higher redox thiol response with the modified NAC regimen at 12 h postdose suggests this regimen may produce greater antioxidant efficacy. At baseline, plasma APAP and purine metabolites may be useful biomarkers for early prediction of APAP-induced ALI.
    Matched MeSH terms: Acetylcysteine/administration & dosage*
  3. Al-Obeed O, Vaali-Mohammed MA, Eldehna WM, Al-Khayal K, Mahmood A, Abdel-Aziz HA, et al.
    Onco Targets Ther, 2018;11:3313-3322.
    PMID: 29892198 DOI: 10.2147/OTT.S148108
    Introduction: Colorectal cancer (CRC) is a major worldwide health problem owing to its high prevalence and mortality rate. Developments in screening, prevention, biomarker, personalized therapies and chemotherapy have improved detection and treatment. However, despite these advances, many patients with advanced metastatic tumors still succumb to the disease. New anticancer agents are needed for treating advanced stage CRC as most of the deaths occur due to cancer metastasis. A recently developed novel sulfonamide derivative 4-((2-(4-(dimethylamino) phenyl)quinazolin-4-yl)amino)benzenesulfonamide (3D) has shown potent antitumor effect; however, the mechanism underlying the antitumor effect remains unknown.

    Materials and methods: 3D-mediated inhibition on cell viability was evaluated by MTT and real-time cell proliferation was measured by xCelligence RTDP instrument. Western blotting was used to measure pro-apoptotic, anti-apoptotic proteins and JAK2-STAT3 phosphorylation. Flow cytometry was used to measure ROS production and apoptosis.

    Results: Our study revealed that 3D treatment significantly reduced the viability of human CRC cells HT-29 and SW620. Furthermore, 3D treatment induced the generation of reactive oxygen species (ROS) in human CRC cells. Confirming our observation, N-acetylcysteine significantly inhibited apoptosis. This is further evidenced by the induction of p53 and Bax; release of cytochrome c; activation of caspase-9, caspase-7 and caspase-3; and cleavage of PARP in 3D-treated cells. This compound was found to have a significant effect on the inhibition of antiapoptotic proteins Bcl2 and BclxL. The results further demonstrate that 3D inhibits JAK2-STAT3 pathway by decreasing the constitutive and IL-6-induced phosphorylation of STAT3. 3D also decreases STAT3 target genes such as cyclin D1 and survivin. Furthermore, a combination study of 3D with doxorubicin (Dox) also showed more potent effects than single treatment of Dox in the inhibition of cell viability.

    Conclusion: Taken together, these findings indicate that 3D induces ROS-mediated apoptosis and inhibits JAK2-STAT3 signaling in CRC.

    Matched MeSH terms: Acetylcysteine
  4. Chan WY, Hickey EE, Page SW, Trott DJ, Hill PB
    J Vet Pharmacol Ther, 2019 Nov;42(6):682-692.
    PMID: 31503362 DOI: 10.1111/jvp.12811
    Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N-acetylcysteine (NAC), Tris-EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm ) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000-10,000 µg/ml and from 20,000-80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris-EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16-fold and eightfold higher than the MIC/MBC of NAC and Tris-EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris-EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm-associated OE in dogs.
    Matched MeSH terms: Acetylcysteine
  5. Garcia S, Bhatt DL, Gallagher M, Jneid H, Kaufman J, Palevsky PM, et al.
    JACC Cardiovasc Interv, 2018 11 26;11(22):2254-2261.
    PMID: 30466822 DOI: 10.1016/j.jcin.2018.07.044
    OBJECTIVES: The aim of this study was to compare intravenous (IV) sodium bicarbonate with IV sodium chloride and oral acetylcysteine with placebo for the prevention of contrast-associated acute kidney injury (CAAKI) and intermediate-term adverse outcomes.

    BACKGROUND: Data are conflicting on the optimal strategy to reduce CAAKI and related complications after percutaneous coronary intervention (PCI).

    METHODS: The PRESERVE (Prevention of Serious Adverse Events Following Angiography) trial used a 2 × 2 factorial design to randomize 5,177 patients with stage III or IV chronic kidney disease undergoing angiography to IV 1.26% sodium bicarbonate or IV 0.9% sodium chloride and 5 days of oral acetylcysteine or placebo. A subgroup analysis was conducted of the efficacy of these interventions in patients who underwent PCI during the study angiographic examination. The primary endpoint was a composite of death, need for dialysis, or persistent kidney impairment at 90 days; CAAKI was a secondary endpoint.

    RESULTS: A total of 1,161 PRESERVE patients (mean age 69 ± 8 years) underwent PCI. The median estimated glomerular filtration rate was 50.7 ml/min/1.73 m2 (interquartile range: 41.7 to 60.1 ml/min/1.73 m2), and 952 patients (82%) had diabetes mellitus. The primary endpoint occurred in 15 of 568 patients (2.6%) in the IV sodium bicarbonate group and 24 of 593 patients (4.0%) in the IV sodium chloride group (odds ratio: 0.64; 95% confidence interval: 0.33 to 1.24; p for interaction = 0.41) and in 23 of 598 patients (3.8%) in the acetylcysteine group and 16 of 563 patients (2.8%) in the placebo group (odds ratio: 1.37; 95% confidence interval: 0.71 to 2.62; p for interaction = 0.29). There were no significant between-group differences in the rates of CAAKI.

    CONCLUSIONS: Among patients with CKD undergoing PCI, there was no benefit of IV sodium bicarbonate over IV sodium chloride or of acetylcysteine over placebo for the prevention of CAAKI or intermediate-term adverse outcomes.

    Matched MeSH terms: Acetylcysteine/administration & dosage*; Acetylcysteine/adverse effects
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