Mono- and di-acylated imidazolidine-2-thione derivatives: synthesis, cytotoxicity evaluation and computational studies

Imidazolidine-2-thione substructure represents a pharmaceutically attractive scaffold, being included in different antimicro- bial, anticancer and pesticide agents. To further evaluate the pharmaceutical potential of this chemical moiety, imidazolidine- 2-thione was reacted with atypical Vilsmeier adducts, obtained by the condensation between dimethylacetamide and various acyl chlorides endowed with different electronic and steric properties. The formation of mono-acylated or di-acylated thio- urea derivatives emerged to be affected by the nature of the considered acyl chloride reagent. Computational semi-empirical simulations were carried out to rationalize the relevant factor influencing the outcome of the reaction. As acylthioureas are pharmacologically relevant compounds, the chemical versatility of mono-acylated derivatives were evaluated by reacting benzoyl imidazolidin-2-thione with acyl chlorides. A small library of asymmetric di-acylthioureas was prepared and the obtained derivatives did not show any cytotoxicity on SKOV-3 and MCF-7 cancer cell lines. Additionally, in silico studies predicted good pharmacokinetics properties and promising drug-like characteristics for mono- and di-acylated thioureas. These considerations further support the value of the prepared compounds as interesting non-cytotoxic chemical scaffold useful in the medicinal chemistry field

Regioselective Synthesis, Structural Characterization, and Antiproliferative Activity of Novel Tetra-Substituted Phenylaminopyrazole Derivatives

A small library of highly functionalized phenylaminopyrazoles, bearing different substituents at position 1, 3 and 4 of the pyrazole ring, was prepared by the one pot condensation of active methylene reagents, phenylisothiocyanate and substituted hydrazine (namely, methyl- and benzyl-hydrazine). The identified reaction conditions proved to be versatile and efficient. Fur-thermore, the evaluation of alternative stepwise protocols affected the chemo- and re-gio-selectivity outcome of the one-pot procedure. The chemical identity of two N-methyl pyrazole isomers, selected as prototypes of the whole series, was unambiguously identified by means of NMR and mass spectrometry studies. Additionally, semiempirical calculations provided a structural rationale for the different chromatographic behaviour of the two isomers. The prepared tetra-substituted phenylaminopyrazoles were tested in cell-based assays on a panel of cancer and normal cell lines. The tested compounds did not show any cytotoxic effect on the selected cell lines, thus supporting their pharmaceutical potentials

Identification of a set of KSRP target transcripts upregulated by PI3K-AKT signaling

BACKGROUND: KSRP is a AU-rich element (ARE) binding protein that causes decay of select sets of transcripts in different cell types. We have recently described that phosphatidylinositol 3-kinase/AKT (PI3K-AKT) activation induces stabilization and accumulation of the labile β-catenin mRNA through an impairment of KSRP function. RESULTS: Aim of this study was to identify additional KSRP targets whose stability and steady-state levels are enhanced by PI3K-AKT activation. First, through microarray analyses of the AU-rich transcriptome in pituitary αT3-1 cells, we identified 34 ARE-containing transcripts upregulated in cells expressing a constitutively active form of AKT1. In parallel, by an affinity chromatography-based technique followed by microarray analyses, 12 mRNAs target of KSRP, additional to β-catenin, were identified. Among them, seven mRNAs were upregulated in cells expressing activated AKT1. Both steady-state levels and stability of these new KSRP targets were consistently increased by either KSRP knock-down or PI3K-AKT activation. CONCLUSION: Our study identified a set of transcripts that are targets of KSRP and whose expression is increased by PI3K-AKT activation. These mRNAs encode RNA binding proteins, signaling molecules and a replication-independent histone. The increased expression of these gene products upon PI3K-AKT activation could play a role in the cellular events initiated by this signaling pathway

A novel calix[4]pyrrole derivative as a potential anticancer agent that forms genotoxic adducts with DNA

meso-(p-acetamidophenyl)-calix[4]pyrrole 3 was found to exhibit remarkable cytotoxicity towards A549 cancer cells. A comparative study including the isomer of 3meso-(m-acetamidophenyl)-calix[4]pyrrole 5, as well as molecules containing \u2018fragments\u2019 of these structures, demonstrated that both the calix[4]pyrrole and the acetamidophenyl units are essential for high cytotoxicity. Although calix[4]pyrroles and other anion-complexing ionophores have recently been reported to induce apoptosis by perturbing cellular chloride concentrations, in our study an alternative mechanism has emerged, as proven by the isolation of covalent DNA adducts revealed by the32P postlabelling technique. Preliminary pharmacokinetic studies indicate that 3 is able to cross the Blood-Brain-Barrier, therefore being a potential drug that could kill primary and brain metastatic cancer cells simultaneously

Two calix[4]pyrroles as potential therapeutics for castration-resistant prostate cancer

Macrocyclic compounds meso-(p-acetamidophenyl)-calix[4]pyrrole and meso-(m-acetamidophenyl)-calix[4]pyrrole have previously been reported to exhibit cytotoxic properties towards lung cancer cells. Here, we report pre-clinical in vitro and in vivo studies showing that these calixpyrrole derivatives can inhibit cell growth in both PC3 and DU145 prostatic cancer cell lines. We explored the impact of these compounds on programmed cell death, as well as their ability to inhibit cellular invasion. In this study we have demonstrated the safety of these macrocyclic compounds by cytotoxicity tests on ex-vivo human peripheral blood mononuclear cells (PBMCs), and by in vivo subcutaneous administration. Preliminary in vivo tests demonstrated no hepato-, no nephro- and no genotoxicity in Balb/c mice compared to controls treated with cisplatin. These findings suggest these calixpyrroles might be novel therapeutic tools for the treatment of prostate cancer and of particular interest for the treatment of androgen-independent castration-resistant prostate cancer

Synthesis, anticancer and antioxidant properties of new indole and pyranoindole derivatives

The indole scaffold has been recognized, over the years, as a model for the synthesis of compounds with anticancer activity by dint of its substantiated ability to act via multiple mechanisms, which also involves the inhibition of enzymes engaged in DNA replication. In this regard, a new series of indole and pyranoindole derivatives have been prepared, some of which showed good antitumor activity and proved their inhibitory effects on the tubulin target. The anticancer activity of the newly synthesized compounds has been evaluated on breast cancer cell lines, as MCF-7 and MDA-MB231, cervical cancer cells line HeLa and Ishikawa endometrial cancer cell line. Among the compounds under study, 7 exhibited a good antitumor activity on HeLa cell line (IC50 = 3.6 ± 0.5), leading to cell death by apoptosis due to the inhibition of tubulin polymerization, which demonstrated that the compound can explicate its function in a similar way to Vinblastine, a well-known inhibitor of tubulin polymerization. The data were also confirmed by in silico assays. No cytotoxicity against normal cells has been detected. Furthermore, in order to investigate the antioxidant properties, DPPH and ABTS tests were performed, together with fluorescence assays on 3T3-L1 cells. All our findings taken together led us to consider compound 7 a favourable candidate for the battle against cancer

Anticancer effects of the Novel Pyrazolyl-Urea GeGe-3

In a screen of over 200 novel pyrazole compounds, ethyl 1-(2-hydroxypentyl)-5-(3-(3-(trifluoromethyl) phenyl)ureido)-1H-pyrazole-4-carboxylate (named GeGe-3) has emerged as a potential anticancer compound. GeGe-3 displays potent anti-angiogenic properties through the presumptive targeting of the protein kinase DMPK1 and the Ca2+-binding protein calreticulin. We furtherexplored the anticancer potential of GeGe-3 on a range of established cancer cell lines, including PC3(prostate adenocarcinoma), SKMEL-28 (cutaneous melanoma), SKOV-3 (ovarian adenocarcinoma),Hep-G2 (hepatocellular carcinoma), MDA-MB231, SKBR3, MCF7 (breast adenocarcinoma), A549(lung carcinoma), and HeLa (cervix epithelioid carcinoma). At concentrations in the range of 10 µM,GeGe-3 significantly restricted cell proliferation and metabolism. GeGe-3 also reduced PC3 cellmigration in a standard wound closure and trans-well assay. Together, these results confirm theanticancer potential of GeGe-3 and underline the need for more detailed pre-clinical investigationsinto its molecular targets and mechanisms of action

The RNA-Binding Protein KSRP Promotes Decay of β-Catenin mRNA and Is Inactivated by PI3K-AKT Signaling

β-catenin plays an essential role in several biological events including cell fate determination, cell proliferation, and transformation. Here we report that β-catenin is encoded by a labile transcript whose half-life is prolonged by Wnt and phosphatidylinositol 3-kinase–AKT signaling. AKT phosphorylates the mRNA decay-promoting factor KSRP at a unique serine residue, induces its association with the multifunctional protein 14-3-3, and prevents KSRP interaction with the exoribonucleolytic complex exosome. This impairs KSRP's ability to promote rapid mRNA decay. Our results uncover an unanticipated level of control of β-catenin expression pointing to KSRP as a required factor to ensure rapid degradation of β-catenin in unstimulated cells. We propose KSRP phosphorylation as a link between phosphatidylinositol 3-kinase–AKT signaling and β-catenin accumulation

Fraisinib: a calixpyrrole derivative reducing A549 cell-derived NSCLC tumor in vivo acts as a ligand of the glycine-tRNA synthase, a new molecular target in oncology

Background and purpose: Lung cancer is the leading cause of death in both men and women, constituting a major public health problem worldwide. Non-small-cell lung cancer accounts for 85%–90% of all lung cancers. We propose a compound that successfully fights tumor growth in vivo by targeting the enzyme GARS1.Experimental approach: We present an in-depth investigation of the mechanism through which Fraisinib [meso-(p-acetamidophenyl)-calix(4)pyrrole] affects the human lung adenocarcinoma A549 cell line. In a xenografted model of non-small-cell lung cancer, Fraisinib was found to reduce tumor mass volume without affecting the vital parameters or body weight of mice. Through a computational approach, we uncovered that glycyl-tRNA synthetase is its molecular target. Differential proteomics analysis further confirmed that pathways regulated by Fraisinib are consistent with glycyl-tRNA synthetase inhibition.Key results: Fraisinib displays a strong anti-tumoral potential coupled with limited toxicity in mice. Glycyl-tRNA synthetase has been identified and validated as a protein target of this compound. By inhibiting GARS1, Fraisinib modulates different key biological processes involved in tumoral growth, aggressiveness, and invasiveness.Conclusion and implications: The overall results indicate that Fraisinib is a powerful inhibitor of non-small-cell lung cancer growth by exerting its action on the enzyme GARS1 while displaying marginal toxicity in animal models. Together with the proven ability of this compound to cross the blood–brain barrier, we can assess that Fraisinib can kill two birds with one stone: targeting the primary tumor and its metastases “in one shot.” Taken together, we suggest that inhibiting GARS1 expression and/or GARS1 enzymatic activity may be innovative molecular targets for cancer treatment