Pharmacokinetic evaluation of the anticancer prodrug simmitecan in different experimental animals

Ursolic acid molecules dock MAPK1 to modulate gut microbiota diversity to reduce neuropathic pain

To investigate the efficacy of Ursolic acid in alleviating neuropathic pain in rats with spinal nerve ligation (SNL), the SNL rat model was surgically induced. Different concentrations of Ursolic acid and manipulated target mitogen-activated protein kinase 1 (MAPK1) were administered to the SNL rats. Fecal samples were collected from each group of rats for 16S rDNA analysis to examine the impact of gut microbiota. Molecular docking experiments were conducted to assess the binding energy between Ursolic acid and MAPK1. In vivo studies were carried out to evaluate the expression of inflammatory factors and signaling pathways in spinal cord and colon tissues. Ursolic acid was found to have a beneficial effect on pain reduction in rats by increasing plantar withdrawal latency (PWL) and paw withdrawal threshold (PWT). Comparing the Ursolic acid group with the control group revealed notable differences in the distribution of Staphylococcus, Allobaculum, Clostridium, Blautia, Bifidobacterium, and Prevotella species. Network pharmacology analysis identified MAPK1 and intercellular adhesion molecule-1 (ICAM1) as common targets for Ursolic acid, SNL, and neuropathic pain. Binding sites between Ursolic acid and these targets were identified. Additionally, immunofluorescent staining showed a decrease in GFAP and IBA1 intensity in the spinal cord along with an increase in NeuN following Ursolic acid treatment. Overexpression of MAPK1 in SNL rats led to an increase in inflammatory factors and a decrease in PWL and PWT. Furthermore, MAPK1 counteracted the pain-relieving effects of Ursolic acid in SNL rats. Ursolic acid was found to alleviate neuropathic pain in SNL rats by targeting MAPK1 and influencing gut microbiota homeostasis.

A validated HPLC-MS/MS method for determination of simmitecan and its metabolite chimmitecan in human plasma and its application to a pharmacokinetic study in Chinese patients with advanced solid tumor

Simmitecan is a new ester anticancer prodrug which can exert the antiproliferation activity through its active metabolite, chimmitecan. In the current study, a simple and reliable liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous determination of simmitecan and chimmitecan in human plasma. Both irinotecan and 7-ethyl-10-hydroxycamptothecin were used as the internal standards. Plasma samples were protein precipitated by acetonitrile (0.2% formic acid, v/v) and processed samples were chromatographed on a Hypersil GOLD^TM C₁₈ column (100 × 4.6 mm, i.d. 3.0 μm) with acetonitrile and 10 mM ammonium acetate (0.1% formic acid, v/v) as the mobile phase. The calibration curves showed good linearity (R ≥ 0.99) over the concentration range of 1-500 ng/mL and 0.25-125 ng/mL for simmitecan and chimmitecan, respectively. Intra- and inter-run precisions (CV%) were ≤10.2% for simmitecan and ≤12.1% for chimmitecan. The accuracies were 99.4-103.5% for simmitecan and 95.4-103.5% for chimmitecan. This method was further successfully applied to a pharmacokinetic study of simmitecan in Chinese advanced solid cancer patients after administration of simmitecan hydrochloride injection.

Investigation on the metabolic characteristics of isobavachin in Psoralea corylifolia L. (Bu-gu-zhi) and its potential inhibition against human cytochrome P450s and UDP-glucuronosyltransferases

OBJECTIVES

Isobavachin is a phenolic with anti-osteoporosis activity. This study aimed to explore its metabolic fates in vivo and in vitro, and to investigate the potential drug-drug interactions involving CYPs and UGTs.

METHODS

Metabolites of isobavachin in mice were first identified and characterized. Oxidation and glucuronidation study were performed using liver and intestine microsomes. Reaction phenotyping, activity correlation analysis and relative activity factor approaches were employed to identify the main CYPs and UGTs involved in isobavachin metabolism. Through kinetic modelling, inhibition mechanisms towards CYPs and UGTs were also explored.

KEY FINDINGS

Two glucuronides (G1 - G2) and three oxidated metabolites (M1 - M3) were identified in mice. Additionally, isobavachin underwent efficient oxidation and glucuronidation by human liver microsomes and HIM with CLint values from 5.53 to 148.79 μl/min per mg. CYP1A2, 2C19 contributed 11.3% and 17.1% to hepatic metabolism of isobavachin, respectively, with CLint values from 8.75 to 77.33 μl/min per mg. UGT1As displayed CLint values from 10.73 to 202.62 μl/min per mg for glucuronidation. Besides, significant correlation analysis also proved that CYP1A2, 2C19 and UGT1A1, 1A9 were main contributors for the metabolism of isobavachin. Furthermore, mice may be the appropriate animal model for predicting its metabolism in human. Moreover, isobavachin exhibited broad inhibition against CYP2B6, 2C9, 2C19, UGT1A1, 1A9, 2B7 with Ki values from 0.05 to 3.05 μm.

CONCLUSIONS

CYP1A2, 2C19 and UGT1As play an important role in isobavachin metabolism. Isobavachin demonstrated broad-spectrum inhibition of CYPs and UGTs.

An Overview of Privileged Scaffold: Quinolines and Isoquinolines in Medicinal Chemistry as Anticancer Agents

Cancer is one of the most difficult diseases and causes of death for many decades. Many pieces of research are continuously going on to get a solution for cancer. Quinoline and isoquinoline derivatives have shown their possibilities to work as an antitumor agent in anticancer treatment. The members of this privileged scaffold quinoline and isoquinoline have shown their controlling impacts on cancer treatment through various modes. In particular, this review suggests the current scenario of quinoline and isoquinoline derivatives as antitumor agents and refine the path of these derivatives to find and develop new drugs against an evil known as cancer.

Camptothecin (CPT) and its derivatives are known to target topoisomerase I (Top1) as their mechanism of action: did we miss something in CPT analogue molecular targets for treating human disease such as cancer?

Camptothecin (CPT) was discovered from plant extracts more than 60 years ago. Since then, only two CPT analogues (irinotecan and topotecan) have been approved for cancer treatment, although several thousand CPT derivatives have been synthesized and many of them were actively studied in our research community over the past 6+ decades. In this review article, we briefly summarize: (1) the discovery and early development of CPTs, (2) the recognized CPT mechanism of action (MOA), (3) the synthesis of CPT and CPT analogues, and (4) the structure-activity relationship (SAR) of CPT and its analogues. Next, we provide evidence that certain CPT analogues can exert improved efficacy with low toxicity independently of topoisomerase I (Top1) inhibition; instead, these CPT analogues use novel MOAs by targeting important cancer survival-associated oncogenic proteins and/or by bypassing various treatment-resistant mechanisms. We then present a comprehensive review of the most advanced CPT analogues in clinical development, with the goal of resolving why no new CPTs have been FDA approved for cancer treatment, beyond irinotecan and topotecan. We argue that new CPT Top1 inhibitor drugs are unlikely being found to be significantly better than irinotecan and/or topotecan in terms of the overall antitumor activity and toxicity. The significance of CPT analogues that possess novel MOAs has not been sufficiently recognized so far. In our opinion, this is a research area with great potential to make a breakthrough for development of the next generation of CPT analogues that possess high efficacy (due to novel targets) and low toxicity (due to low inhibition of Top1 activity/function) for effective treatment of human disease, including cancer.

Emergence of Chinese drug discovery research: impact of hit and lead identification

The identification of hits and the generation of viable leads is an early and yet crucial step in drug discovery. In the West, the main players of drug discovery are pharmaceutical and biotechnology companies, while in China, academic institutions remain central in the field of drug discovery. There has been a tremendous amount of investment from the public as well as private sectors to support infrastructure buildup and expertise consolidation relative to drug discovery and development in the past two decades. A large-scale compound library has been established in China, and a series of high-impact discoveries of lead compounds have been made by integrating information obtained from different technology-based strategies. Natural products are a major source in China's drug discovery efforts. Knowledge has been enhanced via disruptive breakthroughs such as the discovery of Boc5 as a nonpeptidic agonist of glucagon-like peptide 1 receptor (GLP-1R), one of the class B G protein-coupled receptors (GPCRs). Most of the original hit identification and lead generation were carried out by academic institutions, including universities and specialized research institutes. The Chinese pharmaceutical industry is gradually transforming itself from manufacturing low-end generics and active pharmaceutical ingredients to inventing new drugs.