A new mechanism of 6-((2-(dimethylamino)ethyl)amino)-3-hydroxy-7H-indeno(2,1-c)quinolin-7-one dihydrochloride (TAS-103) action discovered by target screening with drug-immobilized affinity beads

Identification of protein biomarkers for prediction of response to platinum-based treatment regimens in patients with non-small cell lung cancer

The majority of patients with resected stage II-IIIA non-small cell lung cancer (NSCLC) are treated with platinum-based adjuvant chemotherapy (ACT) in a one-size-fits-all approach. However, a significant number of patients do not derive clinical benefit, and no predictive patient selection biomarker is currently available. Using mass spectrometry-based proteomics, we have profiled tumour resection material of 2 independent, multi-centre cohorts of in total 67 patients with NSCLC who underwent ACT. Unsupervised cluster analysis of both cohorts revealed a poor response/survival sub-cluster composed of ~ 25% of the patients, that displayed a strong epithelial-mesenchymal transition signature and stromal phenotype. Beyond this stromal sub-population, we identified and validated platinum response prediction biomarker candidates involved in pathways relevant to the mechanism of action of platinum drugs, such as DNA damage repair, as well as less anticipated processes such as those related to the regulation of actin cytoskeleton. Integration with pre-clinical proteomics data supported a role for several of these candidate proteins in platinum response prediction. Validation of one of the candidates (HMGB1) in a third independent patient cohort using immunohistochemistry highlights the potential of translating these proteomics results to clinical practice.

Design, synthesis and biological evaluation of matrine contains benzimidazole derivatives as dual TOPOI and PARP inhibitors for cancer therapy

TOPOI inhibitors have long been a focal point in the research and development of antitumor drugs. PARP-1 plays a crucial role in repairing DNA damage induced by TOPOI inhibitors. Thus, concurrent inhibition of TOPOI and PARP-1 has the potential to augment drug activity. Matrine, characterized by low toxicity and good water solubility, offers advantageous properties. In this investigation, a series of benzimidazole matrine derivatives were designed and synthesized using matrine as the lead compound with the aim of developing dual inhibitors targeting both TOPOI and PARP-1. Among these derivatives, Compound B6 exhibited potent inhibitory effects on PARP-1 and TOPOI, effectively suppressing cancer cell proliferation and migration. Mechanistic assessments revealed that B6 induced DNA damage in HGC-27 cells, leading to G0/G1 cell cycle arrest and significant apoptosis. Molecular docking experiments demonstrated that B6 can effectively enter the active pocket of target proteins, where it forms stable hydrogen bonds with amino acid residues. In vivo, experiments demonstrated that B6 exhibited antitumor activity comparable to that of the positive control drug. The tumor growth inhibition rates (TGIs) for irinotecan, B6 and matrine were 87.0%, 75.4% and 9.7%, respectively. Importantly, B6 demonstrated lower toxicity than the positive control drug. Our findings suggest that TOPOI and PARP-1 may represent potential targets for matrine and B6 emerges as a promising candidate for cancer therapy.

Noncanonical Functions and Cellular Dynamics of the Mammalian Signal Recognition Particle Components

The signal recognition particle (SRP) is a ribonucleoprotein complex fundamental for co-translational delivery of proteins to their proper membrane localization and secretory pathways. Literature of the past two decades has suggested new roles for individual SRP components, 7SL RNA and proteins SRP9, SRP14, SRP19, SRP54, SRP68 and SRP72, outside the SRP cycle. These noncanonical functions interconnect SRP with a multitude of cellular and molecular pathways, including virus-host interactions, stress response, transcriptional regulation and modulation of apoptosis in autoimmune diseases. Uncovered novel properties of the SRP components present a new perspective for the mammalian SRP as a biological modulator of multiple cellular processes. As a consequence of these findings, SRP components have been correlated with a growing list of diseases, such as cancer progression, myopathies and bone marrow genetic diseases, suggesting a potential for development of SRP-target therapies of each individual component. For the first time, here we present the current knowledge on the SRP noncanonical functions and raise the need of a deeper understanding of the molecular interactions between SRP and accessory cellular components. We examine diseases associated with SRP components and discuss the development and feasibility of therapeutics targeting individual SRP noncanonical functions.

Molecular mechanisms of thalidomide and its derivatives

Thalidomide, originally developed as a sedative drug, causes multiple defects due to severe teratogenicity, but it has been re-purposed for treating multiple myeloma, and derivatives such as lenalidomide and pomalidomide have been developed for treating blood cancers. Although the molecular mechanisms of thalidomide and its derivatives remained poorly understood until recently, we identified cereblon (CRBN), a primary direct target of thalidomide, using ferrite glycidyl methacrylate (FG) beads. CRBN is a ligand-dependent substrate receptor of the E3 ubiquitin ligase complex cullin-RING ligase 4 (CRL4^CRBN). When a ligand such as thalidomide binds to CRBN, it recognizes various 'neosubstrates' depending on the shape of the ligand. CRL4^CRBN binds many neosubstrates in the presence of various ligands. CRBN has been utilized in a novel protein knockdown technology named proteolysis targeting chimeras (PROTACs). Heterobifunctional molecules such as dBET1 are being developed to specifically degrade proteins of interest. Herein, we review recent advances in CRBN research.

Identification of a new class of WNT1 inhibitor: Cancer cells migration, G-quadruplex stabilization and target validation

Developing the Wnt pathway inhibitors has been considered as a therapeutic approach for cancers and other Wnt-related diseases. Previously we found that the G-rich sequence of WNT1 promoter is capable of forming G-quadruplex structure and stabilizing agents for Wnt1-mediated signaling pathway. Using a established cell-based drug screen system that enabled the evaluation of WNT1 expression activity in a G-quadruplex structure dependent manner, we evaluated a series of 6-substituted 9-chloro-11H-indeno[1,2-c]quinolin-11-one derivatives that potentially inhibit the Wnt1-mediated signaling pathway. The most potent compound SJ26 showed repression of WNT1 activity in a G-quadruplex structure-dependent manner. Moreover, compound SJ26 inhibited the WNT1-mediated downstream signaling pathway and suppressed migration activity of cancer cells. Thus, we have identified a tetracyclic azafluorenone, SJ26, that is capable of binding to G-quadruplex DNA structure, repressing WNT1 expression, and inhibiting cell migration.

Plasmodium falciparum signal recognition particle components and anti-parasitic effect of ivermectin in blocking nucleo-cytoplasmic shuttling of SRP

Signal recognition particle (SRP) is a ubiquitous ribonucleoprotein complex that targets proteins to endoplasmic reticulum (ER) in eukaryotes. Here we report that Plasmodium falciparum SRP is composed of six polypeptides; SRP9, SRP14, SRP19, SRP54, SRP68 and SRP72 and a 303nt long SRP RNA. We generated four transgenic parasite lines expressing SRP-GFP chimeric proteins and co-localization studies showed the nucleo-cytoplasmic localization for these proteins. The evaluation of the effect of known SRP and nuclear import/export inhibitors on P. falciparum revealed that ivermectin, an inhibitor of importin α/β mediated nuclear import inhibited the nuclear import of PfSRP polypeptides at submicromolar concentration, thereby killing the parasites. These findings provide insights into dynamic structure of P. falciparum SRP and also raise the possibility that ivermectin could be used in combination with other antimalarial agents to control the disease.

Synthesis and antiproliferative evaluation of 9-methoxy-6-(piperazin-1-yl)-11H-indeno[1,2-c]quinoline-11-one derivatives. Part 4

A number of 6,11-disubstituted indenoquinolines were synthesized and evaluated for their antiproliferative activities and mechanism studies.

Synthesis and in vitro antiproliferative effect of novel quinoline-based potential anticancer agents

Several derivatives with a quinoline scaffold and a flexible, semi-flexible or rigid side chains at position 8 of the quinoline ring were synthesized and assessed for their in vitro activity versus the human colon cancer cell line HT29 and the human breast cancer cell line MDA-MB231. The HT29 cell line was more refractory to the cytotoxic activity of some compounds, meanwhile all the quinoline derivatives except one displayed high to moderate activity against MDA-MB231 with IC50 values ranging between 4.6 and 48.2 μM. The most active derivative in this study against both tested cell lines was the Schiff's base 4e with IC50 of 4.7 and 4.6 μM against HT29 and MDA-MB231, respectively.

Uridine 5'-diphospho-glucuronosyltransferase genetic polymorphisms and response to cancer chemotherapy

Pharmacogenetics aims to elucidate how genetic variation affects the efficacy and side effects of drugs, with the ultimate goal of personalizing medicine. Clinical studies of the genetic variation in the uridine 5'-diphosphoglucuronosyltransferase gene have demonstrated how reduced-function allele variants can predict the risk of severe toxicity and help identify cancer patients who could benefit from reduced-dose schedules or alternative chemotherapy. Candidate polymorphisms have also been identified in vitro, although the functional consequences of these variants still need to be tested in the clinical setting. Future approaches in uridine 5'-diphosphoglucuronosyltransferase pharmacogenetics include genetic testing prior to drug treatment, genotype-directed dose-escalation studies, study of genetic variation at the haplotype level and genome-wide studies.

Genomics: applications in mechanism elucidation

The inability to predict the pharmacology and toxicology of drug candidates in preclinical studies has led to the decline in the number of new drugs which make it to market and the rise in cost associated with drug development. Identifying molecular interactions associated with therapeutic and toxic drug effects early in development is a top priority. Traditional mechanism elucidation strategies are narrow, often focusing on the identification of solely the molecular target. Methods which can offer additional insight into wide-ranging molecular interactions required for drug effect and the biochemical consequences of these interactions are in demand. Genomic strategies have made impressive advances in defining a more global view of drug action and are expected to increasingly be used as a complimentary tool in drug discovery and development.

Novel acridine-based compounds that exhibit an anti-pancreatic cancer activity are catalytic inhibitors of human topoisomerase II

We have identified a small library of novel substituted 9-aminoacridine derivatives that inhibit cell proliferation of pancreatic cancer cell lines by inducing apoptosis [Goodell, J.R. et al., 2008. J. Med. Chem. 51, 179-182.]. To further investigate their antiproliferative activities, we have assessed the antiproliferative activity of these acridine-based compounds against several pancreatic cancer cell lines. All four compounds used in this study inhibited the proliferation of pancreatic cancer cell lines in vitro. In addition, we have employed a xenograft tumor model and found that these compounds also inhibit the proliferation of pancreatic cancer in vivo. In light of the potential importance of the anticancer activity of these acridine-based compounds, we have conducted a series of biochemical assays to determine the effect of these compounds on human topoisomerase II. Unlike amsacrine, these compounds do not poison topoisomerase II. Similar to amsacrine, however, these compounds intercalate into DNA in a way that they would alter the apparent topology of the DNA substrate. Thus, inhibition of the relaxation activity of topoisomerase II by these compounds has been reexamined using a DNA strand passage assay. We have found that these compounds, indeed, inhibit the catalytic activity of topoisomerase II. Thus, these novel acridine-based compounds with anti-pancreatic cancer activity are catalytic inhibitors, not poisons, of human topoisomerase II.