Dysregulation of cellular energy metabolism is closely linked to cancer development and progression. Calorie or glucose restriction (CR or GR) inhibits energy-dependent pathways, including IGF-1/PI3K/Akt/mTOR, in cancer cells. However, alterations in proton dynamics and reversal of the pH gradient across the cell membrane, which results in intracellular alkalinization and extracellular acidification in cancer tissues, have emerged as important etiopathogenic factors. We measured glucose, lactate, and ATP production after GR, plant-derived CR-mimetic curcumin treatment, and curcumin plus GR in human hepatoma cells. Intracellular pH regulatory effects, in particular, protein–protein interactions within mTOR complex-1 and its structural change, were investigated. Curcumin treatment or GR mildly inhibited Na+/H+ exchanger-1 (NHE1). vATPase, monocarboxylate transporter (MCT)-1, and MCT4 level. Combination treatment with curcumin and GR further enhanced the inhibitory effects on these transporters and proton-extruding enzymes, with intracellular pH reduction. ATP and lactate production decreased according to pH change. Modeling of mTOR protein revealed structural changes upon treatments, and curcumin plus GR decreased binding of Raptor and GβL to mTOR, as well as of Rag A and Rag B to Raptor. Consequently, 4EBP1 phosphorylation was decreased and cell migration and proliferation were inhibited in a pH-dependent manner. Autophagy was increased by curcumin plus GR. In conclusion, curcumin treatment combined with GR may be a useful supportive approach for preventing intracellular alkalinization and cancer progression.
22 June 2019 in Journal of Clinical Pharmacy and Therapeutics
Background: The increasing prevalence of antimicrobial resistance, together with the lack of novel treatment options, negatively affects successful eradication of Helicobacter pylori. The aim of this study was to investigate genetic mutations in the 23S rRNA genes, which is associated with clarithromycin resistance, and to determine the clinical impact of genotype on phenotypic antimicrobial resistance. Methods: A total of 46 H. pylori strains were obtained from 13 patients, before and after unsuccessful eradication with clarithromycin-based triple therapy. The phenotypic resistance of each H. pylori strain was determined by minimum inhibitory concentration against clarithromycin using the serial two-fold agar dilution method. The genomic sequences of 23S rRNA genes were identified through next-generation sequencing, and nucleotide variants were determined based on comparison with genome sequences of the reference strain H. pylori 26695. Results: Clarithromycin resistance was found in 9 of 13 subjects before treatment and all subjects after unsuccessful eradication. Whole-genome sequencing of the 23S rRNA genes detected 42 mutations on 40 nonidentical loci, including 2147A>G (formerly 2143A>G) and 2146A>G (formerly 2142A>G). All strains with clarithromycin-resistant phenotype had either 2147A>G or 2146A>G mutation. When comparing genotype and phenotype for clarithromycin resistance, there was a significant association between 2147A>G mutation and clarithromycin-resistant phenotype. Conclusions: All clarithromycin-resistant strains had either 2146A>G or 2147A>G mutation, suggesting that tests targeting these two mutations may be enough for the prediction of clarithromycin resistance in this population.
Background: Cell lines are often used to assess the resistance of anticancer drugs when in vivo analysis is not possible. However, the process for establishing anti-cancer drug resistance in cell cultures in vitro and the subsequent method of then evaluating resistance are not clearly established. Traditionally, the IC50 is the most commonly used indicator of resistance evaluation but it cannot represent the effectiveness of anti-cancer drugs in a clinical setting and lacks reliability because it is heavily affected by the cell doubling time. Hence, new indicators that can evaluate anti-cancer drug resistance are needed. Methods: A novel resistance evaluation methodology was validated in this present study by establishing sunitinib resistance in renal cell carcinoma cells and assessing the cross-resistance of five different anti-cancer drugs. Results: It was confirmed in this present study that the IC50 does not reflect the cell proliferation rates in a way that represents anti-cancer drug resistance. An alternative indicator that can also be clinically meaningful when using in vitro cell line systems is GI100. Additionally, the GR100 allows different cell populations to be calibrated on the same basis when multiple experimental results are compared. Conclusion: Since the GR100 has properties that indicate the efficiency of anti-cancer drugs, both the efficacy and GR100 of a particular anti-cancer drug can be used to effectively assess the resistance.
1 May 2023 in Translational Vision Science & Technology
Purpose: Although a comprehensive knowledge of antibiotic/corticosteroid combinations is essential for the appropriate treatment of eye infections, the impact of their co-administration has not been well studied to date. A systematic pharmacodynamic/pharmacokinetic study to determine the effects of cotreatment with various antibiotics and corticosteroids was conducted. Methods: Four bacterial strains, seven antibiotics, and four corticosteroids were used in the analyses. Drug interactions were evaluated by considering antibacterial effects with a checkerboard assay and intracellular concentrations in human corneal epithelial cells. Results: The drug combinations that showed the most stable effects against Pseudomonas aeruginosa was levofloxacin-prednisolone. Stable combinations against the three types of Gram-positive bacteria were neomycin-prednisolone, ofloxacin-dexamethasone, ofloxacin-prednisolone, and polymyxin-dexamethasone. The cellular concentrations were changed for the gatifloxacin-fluorometholone, moxifloxacin-fluorometholone, tobramycin-dexamethasone, and tobramycin-prednisolone combinations. Conclusions: Loteprednol and fluorometholone reduced the antibacterial effects of all of the tested antibiotics in this study. Dexamethasone and prednisolone showed various effects in this regard, depending on the co-administered antibiotic. Prior knowledge of specific antibiotic/corticosteroid interactions provides valuable information to clinical practitioners by combining data on the antibacterial and intracellular uptake effects of their co-administration. Translational Relevance: When using antibiotics and corticosteroids, drug combinations can be selected by referring to the results of this study.
Aims: Several studies have reported that critically ill patients who require amikacin for the treatment of severe infection require therapeutic drug monitoring (TDM) to prevent acute kidney injury. Moreover, studies so far have mainly focused on patients with critical illnesses; therefore, the probability of occurrence of nephrotoxicity in noncritically ill patients is less known and tends to be overestimated. Recently, with the emergence of multidrug resistant bacteria, the need for aminoglycosides has resurfaced. Therefore, the aim of this study was to investigate the nephrotoxicity and tolerability of amikacin in noncritically ill patients. Materials and methods: This was a retrospective study that included 224 patients who were administered amikacin. Relevant data on patients' clinical course of disease, comorbidities, and clinical laboratory measurements were statistically analyzed. Nephrotoxicity was defined as a serum creatinine level increase by >= 0.3 mg/dL or >= 50% after therapy initiation. Results: The mean (SD) daily amikacin dose was 13.04 (4.21) mg/kg. The mean (SD) duration of treatment was 12.09 (12.89) days. The incidence rate (95% CI) of amikacin-induced nephrotoxicity was 1.076/person-year (0.46 - 2.12) for the total person-time (3.44 years). In the risk analysis, no risk factor associated with nephrotoxicity could be found. However, an increasing trend of AKI risk was observed in patients with low baseline estimated glomerular filtration rate. Conclusion: In noncritically ill patients, the incidence of amikacin-induced nephrotoxicity was lower than that reported in previous studies. The initial monitoring for kidney function in clinical laboratories may be useful, and therapeutic drug monitoring (TDM) may not be necessary in patients with normal kidney function.