Target concentration achievement for efficacy and safety of patients with osteosarcoma treated with high-dose methotrexate based on individual pharmacokinetics: A retrospective study

Methotrexate-induced disruption of the serum-glucocorticoid inducible protein kinase 3 signaling pathway and its effects on brain development

Methotrexate (MTX) is a widely used chemotherapeutic and immunosuppressive agent. It is frequently detected in the environment due to its low biodegradability and toxic properties, which may pose risk to humans via contaminated drinking water. MTX impacts brain development; however, the underlying mechanisms remain poorly understood. In this study, we aimed to investigate the potential of brain cortical organoids (COs) to exhibit developmental neurotoxicity upon exposure to MTX and elucidated the underlying mechanisms. We showed that MTX affected brain development by increasing reactive oxygen species production, endoplasmic reticulum stress, and apoptosis in COs, affecting immature neurons, gamma-aminobutyric acid (GABA)ergic neurons, and astrocytes. Treatment with folic acid ameliorated the MTX-induced cellular damage. Furthermore, RNA-seq analysis revealed the significant downregulation of serum/glucocorticoid-regulated kinase family member 3 (SGK3) by MTX treatment. Further investigation using RNA interference with an siRNA targeting SGK3 confirmed that the SGK3 signaling pathway plays an essential role in regulating brain development. Finally, we demonstrated calcium homeostasis disruption in MTX-treated COs (MTX-COs). Our findings suggest that MTX affects cortical development in the brain by increasing intracellular ROS and ER stress, ultimately inducing apoptosis through the inhibition of the SGK3 signaling pathway in MTX-COs. Furthermore, abnormal brain development can be caused by an imbalance in intracellular calcium homeostasis and alterations in the neuronal cell expression in MTX-COs. These results indicate that MTX causes developmental neurotoxicity and underscore the importance of informed decision making regarding the clinical use of MTX, particularly during pregnancy.

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) methods for the therapeutic drug monitoring of cytotoxic anticancer drugs: An update

In the era of precision medicine, there is increasing evidence that conventional cytotoxic agents may be suitable candidates for therapeutic drug monitoring (TDM)- guided drug dosage adjustments and patient's tailored personalization of non-selective chemotherapies. To that end, many liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays have been developed for the quantification of conventional cytotoxic anticancer chemotherapies, that have been comprehensively and critically reviewed. The use of stable isotopically labelled internal standards (IS) of cytotoxic drugs was strikingly uncommon, accounting for only 48 % of the methods found, although their use could possible to suitably circumvent patients' samples matrix effects variability. Furthermore, this approach would increase the reliability of cytotoxic drug quantification in highly multi-mediated cancer patients with complex fluctuating pathophysiological and clinical conditions. LC-MS/MS assays can accommodate multiplexed analyses of cytotoxic drugs with optimal selectivity and specificity as well as short analytical times and, when using stable-isotopically labelled IS for quantification, provide concentrations measurements with a high degree of certainty. However, there are still organisational, pharmacological, and medical constraints to tackle before TDM of cytotoxic drugs can be more largely adopted in the clinics for contributing to our ever-lasting quest to improve cancer treatment outcomes.