Benzylamine and Thenylamine Derived Drugs Induce Apoptosis and Reduce Proliferation, Migration and Metastasis Formation in Melanoma Cells

Melanomas are heterogeneous and aggressive tumors, and one of the worse in prognosis. Melanoma subtypes follow distinct pathways until terminal oncogenic transformation. Here, we have evaluated a series of molecules that exhibit potent cytotoxic effects over the murine and human melanoma cell lines B16F10 and MalMe-3M, respectively, both ex vivo and in animals carrying these melanoma cells. Ex vivo mechanistic studies on molecular targets involved in melanoma growth, migration and viability were evaluated in cultured cells treated with these drugs which exhibited potent proapoptotic and cytotoxic effects and reduced cell migration. These drugs altered the Wnt/β-catenin pathway, which is important for the oncogenic phenotype of melanoma cells. In in vivo experiments, male C57BL/6 or nude mice were injected with melanoma cells that rapidly expanded in these animals and, in some cases were able to form metastasis in lungs. Treatment with anti-tumor drugs derived from benzylamine and 2-thiophenemethylamine (F10503LO1 and related compounds) significantly attenuated tumor growth, impaired cell migration, and reduced the metastatic activity. Several protocols of administration were applied, all of them leading to significant reduction in the tumor size and enhanced animal survival. Tumor cells carrying a luciferase transgene allowed a time-dependent study on the progression of the tumor. Molecular analysis of the pathways modified by F10503LO1 and related compounds defined the main relevant targets for tumor regression: the activation of pro-apoptotic and anti-proliferative routes. These data might provide the proof-of-principle and rationale for its further clinical evaluation.

Bilastine: an environmental risk assessment

CONTEXT

Bilastine is a new oral selective, non-sedating histamine H1 antagonist for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. The European Medicines Agency requires an Environmental Risk Assessment (ERA) for all novel medicines for human use.

OBJECTIVE

To calculate the bilastine predicted environmental concentration in surface water (PECsw; phase I ERA), and to determine the effects of bilastine on aquatic systems (phase II [tier A]).

MATERIALS AND METHODS

Bilastine PECsw was calculated using the maximum daily dosage (20 mg), assuming that all administered bilastine was released into the aquatic environment. A persistence, bioaccumulation and toxicity assessment was conducted using the log Kow from the molecular structure. In phase II (tier A), a ready biodegradability test was performed, and bilastine's potential toxicity to various aquatic and sediment-dwelling micro-organisms was evaluated.

RESULTS

Bilastine PECSW was calculated as 0.1 μg L(-1), and the compound was not readily biodegradable. Bilastine had no significant effects on Chironomus riparius midges, or on the respiration rate of activated sludge. For green algae, the bilastine no observed effect concentration (NOEC) was 22 mg L(-1); bilastine had no effect on zebra fish development, or on the reproduction rate of daphnids.

DISCUSSION

Bilastine NOEC values against zebra fish, algae, daphnids, and aerobic organisms in activated sludge were at least 130 000-fold greater than the calculated PECSW value.

CONCLUSION

No environmental concerns exist from bilastine use in patients with allergic rhinoconjunctivitis or urticaria.

Synthesis of 1,5-diarylpyrazol-3-propanoic acids towards inhibition of cyclooxygenase-1/2 activity and 5-lipoxygenase-mediated LTB4 formation

A set of 25 derivatives of 3-[1-(6-substituted-pyridazin-3-yl)-5-(4-substituted-phenyl)-1H-pyrazol-3-yl]propanoic acids has been synthesized and evaluated for their in vitro cyclooxygenase-1/2 (COX-1/ 2) inhibitory activity using assays with purified COX-1 and COX-2 enzymes as well as for their 5-lipoxygenase (5-LO)-mediated LTB4 formation inhibitory activity using an assay with activated human polymorphonuclear leukocytes (PMNL). Among the synthesized compounds, especially 4g showed COX-1 (IC50 = 1.5 microM) and COX-2 (IC50 = 1.6 microM) inhibitory activity, whereas compounds 4 b and 4 f resulted in the inhibition of 5-LO-mediated LTB4 formation at 14 microM and 12 microM IC50 values, respectively, without any significant inhibition on COX isoforms.

Synthesis, biological evaluation, and docking studies of novel heterocyclic diaryl compounds as selective COX-2 inhibitors

Three novel series of diaryl heterocyclic derivatives bearing the 2-oxo-5H-furan, 2-oxo-3H-1,3-oxazole, and 1H-pyrazole moieties as the central heterocyclic ring were synthesized and their in vitro inhibitory activities on COX-1 and COX-2 isoforms were evaluated using a purified enzyme assay. The 2-oxo-5H-furan derivative 6b was identified as potent COX inhibitor with selectivity toward COX-1 (COX-1 IC(50)=0.061 microM and COX-2 IC(50)=0.325 microM; selectivity index (SI)=0.19). Among the 1H-pyrazole derivatives, 11b was found to be a potent COX-2 inhibitor, about 38 times more potent than Rofecoxib (COX-2 IC(50)=0.011 microM and 0.398 microM, respectively), but showed no selectivity for COX-2 isoform. Compound 11c demonstrated strong and selective COX-2 inhibitory activity (COX-1 IC(50)=1 microM, COX-2 IC(50)=0.011 microM; SI= approximately 92). Molecular docking studies of compounds 6b and 11b-d into the binding sites of COX-1 and COX-2 allowed to shed light on the binding mode of these novel COX inhibitors.

The DREAM-DRE interaction: key nucleotides and dominant negative mutants

Transcriptional repressor DREAM, an EF-hand containing calcium-binding protein, blocks basal expression of target genes through specific interaction with DRE sites in the DNA. The sequence GTCA forms the central core of the DRE site, whereas flanking nucleotides contribute notably to the affinity for DREAM. Release of binding of DREAM from the DRE results in derepression, a process that is regulated by Ca(2+). Change of two amino acids within an EF-hand in DREAM blocks Ca(2+)-induced derepression and results in potent dominant negative mutants of endogenous DREAM.

DREAM-alphaCREM interaction via leucine-charged domains derepresses downstream regulatory element-dependent transcription

Protein kinase A-dependent derepression of the human prodynorphin gene is regulated by the differential occupancy of the Dyn downstream regulatory element (DRE) site. Here, we show that a direct protein-protein interaction between DREAM and the CREM repressor isoform, alphaCREM, prevents binding of DREAM to the DRE and suggests a mechanism for cyclic AMP-dependent derepression of the prodynorphin gene in human neuroblastoma cells. Phosphorylation in the kinase-inducible domain of alphaCREM is not required for the interaction, but phospho-alphaCREM shows higher affinity for DREAM. The interaction with alphaCREM is independent of the Ca(2+)-binding properties of DREAM and is governed by leucine-charged residue-rich domains located in both alphaCREM and DREAM. Thus, our results propose a new mechanism for DREAM-mediated derepression that can operate independently of changes in nuclear Ca(2+).

DREAM is a Ca2+-regulated transcriptional repressor

Fluxes in amounts of intracellular calcium ions are important determinants of gene expression. So far, Ca2+-regulated kinases and phosphatases have been implicated in changing the phosphorylation status of key transcription factors and thereby modulating their function. In addition, direct effectors of Ca2+-induced gene expression have been suggested to exist in the nucleus, although no such effectors have been identified yet. Expression of the human prodynorphin gene, which is involved in memory acquisition and pain, is regulated through its downstream regulatory element (DRE) sequence, which acts as a location-dependent gene silencer. Here we isolate a new transcriptional repressor, DRE-antagonist modulator (DREAM), which specifically binds to the DRE. DREAM contains four Ca2+-binding domains of the EF-hand type. Upon stimulation by Ca2+, DREAM's ability to bind to the DRE and its repressor function are prevented. Mutation of the EF-hands abolishes the response of DREAM to Ca2+. In addition to the prodynorphin promoter, DREAM represses transcription from the early response gene c-fos. Thus, DREAM represents the first known Ca2+-binding protein to function as a DNA-binding transcriptional regulator.

Heart fatty acid unsaturation and lipid peroxidation, and aging rate, are lower in the canary and the parakeet than in the mouse

Despite their high metabolic rates, birds have a much higher maximum longevity (MLSP) than mammals of similar body size, and thus represent ideal models for identifying longevity characteristics not linked to low metabolic rates. This study shows that the fatty acid double bond content of both canary (MLSP = 24 years) and parakeet (MLSP = 21 years) hearts is intrinsically lower than in mouse (MLSP = 3.5 years) heart. This is caused by a redistribution between types of unsaturated fatty acids, mainly due to a lower content of the most highly unsaturated docosahexaenoic acid (22:6n-3) in the two birds in relation to the mammal. The lower double bond content leads to a lower sensitivity to lipid peroxidation, and to a lower level of in vivo lipid peroxidation in the heart of parakeets and canaries than in that of mice. Similar results have been previously found comparing liver mitochondria of rats and pigeons and tissues of different mammalian species. All these results taken together suggest that a low degree of fatty acid unsaturation is a general characteristic of longevous homeothermic vertebrate animals, both when they have low metabolic rates (mammals of large body size) or high metabolic rates (the studied birds); this constitutive trait protects their tissues and organelles against free radical mediated lipid peroxidation, and can contribute to their slow aging rate.