Design,synthesis, and biological evaluation of novel substituted thiourea derivatives as potential anticancer agents for NSCLC by blocking K-Ras protein-effectors interactions

Abstract

Mutation of the proto-oncogene K-Ras is one of the most common molecular mechanisms in non-small cell lung cancer. Many drugs for treating lung cancer have been developed, however, due to clinical observed K-Ras mutations, corresponding chemotherapy and targeted therapy for such mutation are not efficient enough. In this study, on the basis of the crystal structure of K-Ras, 21 analogues (TKR01–TKR21) containing urea or thiourea were rationally designed, which can effectively inhibit the lung cancer cell A549 growth. The designing of these compounds was based on the structure of K-Ras protein, and the related groups were replaced by bioisosteres to improve the affinity and selectivity. Biological testing revealed that compound TKR15 could significantly inhibit the proliferation of A549 cell with IC₅₀ of 0.21?µM. Docking analysis showed that the TKR15 can effectively bind to the hydrophobic cavity and form a hydrogen bond with the Glu37. In addition, through flow apoptosis assay and immunofluorescence staining assay, it confirmed that this compound can inhibit A549 cell proliferation with the mechanism of blocking K-Ras^G12V protein and effector proteins interactions through the apoptotic pathway. In conclusion, our studies in finding novel potent compound (TKR15) with confirmed mechanism showed great potential for further optimisation and other medicinal chemistry relevant studies.     

Proteomics and metabolomics in cancer drug development

In this review article, the main recent advancements in the field of proteomics and metabolomics and their application in cancer research are described. In the second part of the review the main metabolic alterations observed in cancer cells are thoroughly dissected, especially those involving anabolic pathways and NADPH-generating pathways, which indirectly affect anabolic reactions, other than the maintenance of the redox poise. Alterations to mitochondrial pathways and thereby deriving oncometabolites are also detailed. The third section of the review is a discussion of how and to what extent (mutations to) tumor suppressors and oncogenes end up influencing cancer cell metabolism and cell fate, either promoting survival and proliferation or autophagy and apoptosis. In the last section of the review, an overview is provided of therapeutic strategies that make use of metabolic reprogramming approaches.     

Emerging liquid chromatography–mass spectrometry technologies improving dried blood spot analysis

Dried blood spots (DBS), a micro blood sampling technique, has recently gained interest in drug discovery and development due to its inherent advantages over the conventional whole blood, plasma or serum sample collection. Since the regulatory authorities have agreed to the use of blood as an acceptable biological matrix for drug exposure measurements, its applications have been extended not only to therapeutic drug monitoring but also to toxicokinetic and pharmacokinetic studies. The pharmaceutical industry is keen to promote DBS as a prominent tool in bioanalytical applications due to the financial, ethical and organizational issues involved in clinical trials. This could be accomplished due to the latest advances in modern analytical technology, particularly liquid chromatography–mass spectrometry. The present review discusses some of the emerging liquid chromatography–mass spectrometry technologies in improving DBS analysis for its innovative applications in the development of new drugs.     

Lipophilic Prodrugs and Formulations of Conventional (Deoxy)Nucleoside and Fluoropyrimidine Analogs in Cancer

Many drugs that are currently used for the treatment of cancer have limitations, such as induction of resistance and/or poor biological half-life, which reduce their clinical efficacy. To overcome these limitations, several strategies have been explored. Chemical modification by the attachment of lipophilic moieties to (deoxy)nucleoside analogs should enhance the plasma half-life, change the biodistribution, and improve cellular uptake of the drug. Attachment of a lipophilic moiety to a phosphorylated (deoxy)nucleoside analog will improve the activity of the drugs by circumventing the rate-limiting activation step of (deoxy)nucleoside analogs. Encapsulating drugs in nanoparticles or liposomes protects the drug against enzymatic breakdown in the plasma and makes it possible to get lipophilic compounds to the tumor site. In this review, we discuss the considerable progress that has been made in increasing the efficacy of classic (deoxy)nucleoside and fluoropyrimidine compounds by chemical modifications and alternative delivery systems.     

Update on the pathobiology of neuropathic pain

Nerve injury or dysfunction in the peripheral and central nervous systems are the leading causes for the development of neuropathies, which are frequently associated with allodynia and hyperalgesia. Treatment of these disorders is often unsatisfactory due to side effects or insufficient analgesia of the currently available drugs. Therefore, elucidating the molecular mechanisms of neuropathic pain is an important prerequisite for the rational development of novel analgesic drugs for the therapy of neuropathic pain. Several proteomic approaches have been performed to explore protein modifications in the nervous system associated with neuropathies in different animal models, which might contribute to the detection of new drug targets. Furthermore, there are proteomic studies investigating human cerebrospinal fluid from patients suffering from neuropathies. The results of these studies and the potential clinical value of the proteomic data are summarized and discussed in this review.     

Why minimal is not optimal: Driving the mammalian cell cycle—and drug discovery—with a physiologic CDK control network

Progression through the eukaryotic cell division cycle is governed by the activity of cyclin-dependent kinases (CDKs). For a CDK to become active it must (1) bind a positive regulatory subunit (cyclin) and (2) be phosphorylated on its activation (T) loop. In metazoans, multiple CDK catalytic subunits, each with a distinct set of preferred cyclin partners, regulate the cell cycle, but it has been difficult to assign functions to individual CDKs in vivo. Biochemical analyses and experiments with dominant-negative alleles suggested that specific CDK/cyclin complexes regulate different events, but genetic loss of interphase CDKs (Cdk2, -4 and -6), alone or in combination, did not block proliferation of cells in culture. These knockout and knockdown studies suggested redundancy or plasticity built into the CDK network but did not address whether there was true redundancy in normal cells with a full complement of CDKs. Here, we discuss recent work that took a chemical-genetic approach to reveal that the activity of a genetically non-essential CDK, Cdk2, is required for cell proliferation when normal cyclin pairing is maintained. These results have implications for the systems-level organization of the cell cycle, for regulation of the restriction point and G?/S transition and for efforts to target Cdk2 therapeutically in human cancers.     

Translation of proteomic biomarkers into FDA approved cancer diagnostics: issues and challenges

Tremendous efforts have been made over the past few decades to discover novel cancer biomarkers for use in clinical practice. However, a striking discrepancy exists between the effort directed toward biomarker discovery and the number of markers that make it into clinical practice. One of the confounding issues in translating a novel discovery into clinical practice is that quite often the scientists working on biomarker discovery have limited knowledge of the analytical, diagnostic, and regulatory requirements for a clinical assay. This review provides an introduction to such considerations with the aim of generating more extensive discussion for study design, assay performance, and regulatory approval in the process of translating new proteomic biomarkers from discovery into cancer diagnostics. We first describe the analytical requirements for a robust clinical biomarker assay, including concepts of precision, trueness, specificity and analytical interference, and carryover. We next introduce the clinical considerations of diagnostic accuracy, receiver operating characteristic analysis, positive and negative predictive values, and clinical utility. We finish the review by describing components of the FDA approval process for protein-based biomarkers, including classification of biomarker assays as medical devices, analytical and clinical performance requirements, and the approval process workflow. While we recognize that the road from biomarker discovery, validation, and regulatory approval to the translation into the clinical setting could be long and difficult, the reward for patients, clinicians and scientists could be rather significant.     

Inhibition of PrPSc formation in scrapie infected N2a cells by 5,7,8-trimethyl-3,4-dihydro-2H-1,4-benzoxazine derivatives

Prion diseases are fatal, neurodegenerative diseases characterized by the structural conversion of the normal, cellular prion protein, PrP^C into an abnormally structured, aggregated and partially protease-resistant isoform, termed PrP^Sc. Although substantial research has been directed toward development of therapeutics targeting prions, there is still no curative treatment for the disease. Benzoxazines are bicyclic heterocyclic compounds possessing several pharmaceutically important properties, including neuroprotection and reactive oxygen species scavenging. In an effort to identify novel inhibitors of prion formation, several 5,7,8-trimethyl-1,4-benzoxazine derivatives were evaluated in vitro for their effectiveness on the expression levels of normal PrP^C and its conversion to the abnormal isoforms of PrP^Sc in a scrapie-infected cell culture model. The most potent compound was 2-(4-methoxyphenyl)-5,7,8-trimethyl-3,4-dihydro-2H-1,4-benzoxazine, with a diminishing effect on the formation of PrP^Sc, thus establishing a class of compounds with a promising therapeutic use against prion diseases.