latrunculin-a and Neoplasms

Currently, cancer and its progression to metastasis result in a large number of deaths. The lack of new drugs, appropriate clinical trials for metastasis preventive drugs and incomplete understanding of the molecular machinery are the major obstacles in metastasis prevention and treatment. On the other hand, thiosemicarbazones and their bioisosteres, thiazole and thiazolidinone are recurring in a wide range of biologically active compounds that reach different targets within tumor context and represent a promising start point to access potential candidates in metastatic cancer. Therefore, the search for new lead compounds showing highest anticancer potency and less adverse effects is the major challenger in drug discovery. The search was based from 1994 to 2018, focusing on thiosemicarbazone, thiazole and thiazolidinone cores that allowed us to discuss how the three multi-target motifs have been used for the target-based design and development of anticancer agents. In the lasts years, thiosemicarbazone, thiazole, and thiazolidinone cores are recurrent in many approaches for cancer therapy. In our search, it was verified that due to its biodiversity and versatility the anticancer potential of such structures has been assigned to distinct mechanisms reinforcing the value of these cores in the anticancer drug development. The present article aims point out the current application of thiosemicarbazone, thiazole and thiazolidinone cores in the design of anticancer agents within tumor progression, acting via varied targets such as cathepsins, NDRG1 gene and kinases, showing in vitro tests, in vivo tests and clinical trials. In our search it was possible to verify that thiazole is the most studied and the most important of the three structures. Therefore, we hope to provide new insights and valuable inspiration in the research of new drugs and development and contribute to the management of cancer.

Topics: Animals; Antineoplastic Agents; Cell Cycle Proteins; Disease Progression; Drug Delivery Systems; Drug Discovery; Humans; Intracellular Signaling Peptides and Proteins; Neoplasms; Thiazoles; Thiazolidines; Thiosemicarbazones

Human antigen R (HuR) is a RNA-binding protein, which binds to the AU-rich element (ARE) in the 3'-untranslated region (3'-UTR) of certain mRNA and is involved in the export and stabilization of ARE-mRNA. HuR constitutively relocates to the cytoplasm in many cancer cells, however the mechanism of intracellular HuR trafficking is poorly understood. To address this question, we examined the functional role of the cytoskeleton in HuR relocalization. We tested the effect of actin depolymerizing macrolide latrunculin A or myosin II ATPase activity inhibitor blebbistatin for HuR relocalization induced by the vasoactive hormone Angiotensin II in cancer and control normal cells. Western blot and confocal imaging data revealed that both inhibitors attenuated the cytoplasmic HuR in normal cells but no such alteration was observed in cancer cells. Concomitant with changes in intracellular HuR localization, both inhibitors markedly decreased the accumulation and half-lives of HuR target ARE-mRNAs in normal cells, whereas no change was observed in cancer cells. Furthermore, co-immunoprecipitation experiments with HuR proteins revealed clear physical interaction with ß-actin only in normal cells. The current study is the first to verify that cancer cells can implicate a microfilament independent HuR transport. We hypothesized that when cytoskeleton structure is impaired, cancer cells can acquire an alternative HuR trafficking strategy.

Topics: 3' Untranslated Regions; Actins; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cytoplasm; Cytoskeleton; ELAV-Like Protein 1; HeLa Cells; Hep G2 Cells; Heterocyclic Compounds, 4 or More Rings; Humans; Myosins; Neoplasms; Protein Binding; Protein Transport; RNA Stability; RNA, Messenger; Thiazolidines

Nanoparticle (NPs) delivery systems in vivo promises to overcome many obstacles associated with the administration of drugs, vaccines, plasmid DNA and RNA materials, making the study of their cellular uptake a central issue in nanomedicine. The uptake of NPs may be influenced by the cell culture stage and the NPs physical-chemical properties. So far, controversial data on NPs uptake have been derived owing to the heterogeneity of NPs and the general use of immortalized cancer cell lines that often behave differently from each other and from primary mammalian cell cultures. Main aims of the present study were to investigate the uptake, endocytosis pathways, intracellular fate and release of well standardized model particles, i.e. fluorescent 44 nm polystyrene NPs (PS-NPs), on two primary mammalian cell cultures, i.e. bovine oviductal epithelial cells (BOEC) and human colon fibroblasts (HCF) by confocal microscopy and spectrofluorimetric analysis. Different drugs and conditions that inhibit specific internalization routes were used to understand the mechanisms that mediate PS-NP uptake. Our data showed that PS-NPs are rapidly internalized by both cell types 1) with similar saturation kinetics; 2) through ATP-independent processes, and 3) quickly released in the culture medium. Our results suggest that PS-NPs are able to rapidly cross the cell membrane through passive translocation during both uptake and release, and emphasize the need to carefully design NPs for drug delivery, to ensure their selective uptake and to optimize their retainment in the targeted cells.

Topics: Amiloride; Animals; Biological Transport; Bridged Bicyclo Compounds, Heterocyclic; Cattle; Caveolin 1; Cell Membrane; Cells, Cultured; Colon; Drug Delivery Systems; Endocytosis; Epithelial Cells; Female; Fibroblasts; Humans; Hydrazones; Microscopy, Confocal; Nanoparticles; Neoplasms; Oviducts; Particle Size; Polystyrenes; Primary Cell Culture; Spectrometry, Fluorescence; Sucrose; Thiazolidines

Macromolecular complexes exhibit reduced diffusion in biological membranes; however, the physiological consequences of this characteristic of plasma membrane domain organization remain elusive. We report that competition between the galectin lattice and oligomerized caveolin-1 microdomains for epidermal growth factor (EGF) receptor (EGFR) recruitment regulates EGFR signaling in tumor cells. In mammary tumor cells deficient for Golgi beta1,6N-acetylglucosaminyltransferase V (Mgat5), a reduction in EGFR binding to the galectin lattice allows an increased association with stable caveolin-1 cell surface microdomains that suppresses EGFR signaling. Depletion of caveolin-1 enhances EGFR diffusion, responsiveness to EGF, and relieves Mgat5 deficiency-imposed restrictions on tumor cell growth. In Mgat5(+/+) tumor cells, EGFR association with the galectin lattice reduces first-order EGFR diffusion rates and promotes receptor interaction with the actin cytoskeleton. Importantly, EGFR association with the lattice opposes sequestration by caveolin-1, overriding its negative regulation of EGFR diffusion and signaling. Therefore, caveolin-1 is a conditional tumor suppressor whose loss is advantageous when beta1,6GlcNAc-branched N-glycans are below a threshold for optimal galectin lattice formation.

Topics: Actins; Animals; Bridged Bicyclo Compounds, Heterocyclic; Caveolin 1; Cell Membrane; Cytoskeleton; Diffusion; Embryonic Stem Cells; Enzyme Activation; Epidermal Growth Factor; ErbB Receptors; Fluorescence Recovery After Photobleaching; Galectins; Mice; Models, Biological; Neoplasms; Nerve Tissue Proteins; Phosphorylation; Protein Structure, Tertiary; Protein Transport; Recombinant Fusion Proteins; Signal Transduction; Thiazolidines