Impact of valproic acid on busulfan pharmacokinetics: In vitro assessment of potential drug-drug interaction.

Busulfan (Bu) is an alkylating agent commonly used at high doses in the preparative regimens of hematopoietic stem cell transplantation (HSCT). It has been shown that such high doses of Bu are associated with generalized seizures which are usually managed by prophylactic antiepileptic drugs (AEDs) such as valproic acid (VPA). Being a strong enzyme inhibitor, VPA may inhibit Bu metabolism and thus increase its potential toxicity. Despite its clinical relevance, the potential interaction between Bu and VPA has not yet been evaluated. The aim of the present study was to assess and evaluate the potential drug-drug interaction (DDI) between Bu and VPA. This study was carried out by incubating Bu in laboratory-prepared rat liver-subcellular fractions including S9, microsomes, and cytosol, alone or in combination with VPA. The liver fractions were prepared by differential centrifugation of the liver homogenate. Analysis of Bu was employed using a fully validated LC-MS/MS method. The validation parameters were within the proposed limits of the international standards guidelines. Bu metabolic stability was assessed by incubating Bu at a concentration of 8 µg/ml in liver fractions at 37°C. There were significant reductions in Bu levels in S9 and cytosolic fractions, whereas these levels were not significantly (P ˃ 0.05) changed in microsomes. However, in presence of VPA, Bu levels in S9 fraction remained unchanged. These results indicated, for the first time, the potential metabolic interaction of Bu and VPA being in S9 only. This could be explained by inhibiting Bu cytosolic metabolism by the interaction with VPA either by sharing the same metabolic enzyme or the required co-factor. In conclusion, the present findings suggest, for the first time, a potential DDI between Bu and VPA in vitro using rat liver fractions. Further investigations are warranted in human-derived liver fractions to confirm such an interaction.

Anti-progressive Effects of a Series of Glycinyl and Alaninyl Triazolyl-oxazolidinones on Kelly Neuroblastoma Cell Line.

BACKGROUND/AIM: Neuroblastoma (NB), the most common extracranial malignant childhood tumor accounts for about 15% of cancer-related deaths in children. Despite the intensive treatment of patients with high-risk scarification of NB, clinical outcomes indicate tumor recurrence greater than 50% and late severe adverse effects. Oxazolidinones are 5-membered heterocyclic compounds with antibacterial activity against resistant bacterial strains. Structural modifications around the oxazolidinone moiety have resulted in derivatives with anti-cancer properties against proliferation, motility, and invasion of breast cancer cells. This study aimed to examine the anti-cancer potential of novel oxazolidinones against a model of a neuroblastoma cell line. MATERIALS AND METHODS: Newly synthesized and characterized triazolyl-oxazolidinone derivatives were incubated with neuroblastoma Kelly cells. The anti-proliferation and anti-progression effects of the compounds were evaluated by MTT, and adhesion with migration assays. RESULTS: The 5-nitrofuroyl glycinyl-oxazolidinone containing 4-methyltriazolyl group demonstrated the most potent activity with an IC50=6.52 µM. Furthermore, the D-isomer of 5-nitrothiophenecarbonyl alaninyl containing derivative reduced the adhesion to fibronectin by 56.34%, while the D-isomer of 5-nitrofuroyl alaninyl derivative reduced the migration of Kelly cells by 29.14%. CONCLUSION: The presence of the 4-methyltriazolyl moiety seems to enhance the anti-proliferative property of triazolyl-oxazolidinone derivatives, as demonstrated by PH-145. There is little or no effect of the stereochemistry of the alanine side-chain on the antiproliferative effect, as demonstrated by the 5-nitrofuroyl D- and L-alaninyl containing derivatives with similar IC50 values. The observed differences in the inhibition of adhesion and migration by the oxazolidinones on Kelly cells provide a new therapeutic approach that needs further investigation.

The In Vitro Anti-Proliferative Interaction of Flavonoid Quercetin and Toxic Metal Cadmium in the 1321N1 Human Astrocytoma Cell Line.

Cadmium (Cd) is a toxic heavy metal occurring in the environment as an industrial pollutant. The systematic accumulation of Cd in the human body may lead to major health problems. Quercetin (QE) is a natural flavonoid widely distributed in plants and is a part of human diet. Many studies have demonstrated the multiple benefits of QE to humans in protecting cells of our bodies. The aim of this study was to investigate the effect of QE and Cd on the proliferation of astrocytoma 1321N1 cells. Results indicated that the simultaneous exposure of the cells to 200 µM QE and 16 µM Cd significantly reduced cell viability to 6.9 ± 1.6% with respect to vehicle-treated cells. Other experiments of QE pre-treatment followed by the exposure to Cd alone or with QE indicated significant but decreased ability of QE or Cd to reduce proliferation of the cells compared to their co-incubation. Our study suggested a synergetic anti-proliferative interaction of Cd and QE in malignantly transformed cells. This adds new information regarding the biological effects of QE.

The zebrafish model of tuberculosis - no lungs needed.

Tuberculosis is still a global health burden. It is caused by Mycobacterium tuberculosis which afflicts around one third of the world's population and costs around 1.3 million people their lives every year. Bacillus Calmette-Guerin vaccine is inefficient to prevent overt infection. Additionally, the lengthy inconvenient course of treatment, along with the raising issue of antimicrobial resistance, result in incomplete eradication of this infectious disease. The lack of proper animal models that replicate the latent and active courses of human tuberculosis infection remains one of the main reasons behind the poor advancement in tuberculosis research. Danio rerio, commonly known as zebrafish, is catching more attention as an animal model in tuberculosis research field. This shift is based on the histological and pathological similarities between Mycobacterium marinum infection in zebrafish and Mycobacterium tuberculosis infection in humans. Being small, cheap, transparent, and easy to handle have added further advantages to the use of zebrafish model. Besides better understanding of the pathogenesis of tuberculosis, Mycobacterium marinum infected zebrafish model is useful for evaluating novel vaccines against human tuberculosis, high throughput small molecule screening, repurposing established drugs with possible antitubercular activity, and assessing novel antituberculars for hepatotoxicity.

Phosphofructokinase: a mediator of glycolytic flux in cancer progression.

In view of the current limitations of cancer chemotherapy, there has been resurgent interest in re-visiting glycolysis to determine whether tumors could be killed by energy deprivation rather than solely by strategies to inhibit proliferation. Cancer cells exhibit a uniquely high rate of glucose utilization, converting it into lactate whose export subsequently creates an acidic extracellular environment that is thought to promote invasion and metastasis, in preference to its complete oxidation even in the presence of adequate oxygen supply. Reductive analysis of each step of glycolysis shows that, of the three rate limiting enzymes of the pathway, isoforms of phosphofructokinase may afford the greatest opportunity as targets to deprive cancer cells from essential energy and substrates for macromolecular synthesis for proliferation while allowing normal cells to survive. Strategies discussed include restricting the substrate for this enzyme. While prospects for monotherapy with glycolytic inhibitors are poor, combination therapy may be productive.