5 research outputs found

    Additional file 3: of EIF2A-dependent translational arrest protects leukemia cells from the energetic stress induced by NAMPT inhibition

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    Effects of CHS-828 and chemotherapeutics on protein translation. A) Jurkat cells were treated for 48 h with or without (Mock) the indicated concentration of CHS-828. Caspase 3/7 activity was quantified (using 5 μM of Camptothecin for 4 h as a positive control of apoptosis) and relative ATP levels were determined and then normalized to the number of viable cells. The levels of total AMPK, p-AMPK, total EIF2A and p-EIF2A, total 4EBP1, p-4EBP1 were evaluated by WB. Histogram shows the densitometric analysis of p-AMPK and p-EIF2A (* indicates p-value <0.05). Mean and SD of a biological triplicate. B) Jurkat cells were treated with the indicated concentration of drugs for 48 h and cell viability was measured by Cell Titer Glo. Data are represented as mean and SD of three independent experiments. C) Click-it chemistry based on the incorporation of an aminoacid analog (AHA) was used to monitor protein synthesis. Jurkat cells were treated for 48 h with or without (Mock) the indicated concentration of FK866, Rapamycin (RAPA), Doxorubicin (DOXO), Cisplatin (CIS) and Dexamethasone (DEXA). The histogram quantifies the % of AHA positive cells (active protein-synthesizing cells) in the viable cell population. Flow-cytometry experiments were carried out on two biological replicates and statistics were based on acquisition of 20000 events/sample. D) Jurkat cells were treated as in C and the level of p-EIF2A and p-4EBP1 was evaluated. Histogram shows the densitometric analysis of p-EIF2A (* indicates p-value <0.05). Mean and SD of a biological triplicate. E) Primary B-CLL cells were treated for 48 h with or without 30 nM FK866 in the presence or absence of 1 mM NA. Histogram shows the densitometric analysis of p-AMPK/AMPK. (PDF 691 kb

    Interfering with HuR–RNA Interaction: Design, Synthesis and Biological Characterization of Tanshinone Mimics as Novel, Effective HuR Inhibitors

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    The human antigen R (HuR) is an RNA-binding protein known to modulate the expression of target mRNA coding for proteins involved in inflammation, tumorigenesis, and stress responses and is a valuable drug target. We previously found that dihydrotanshinone-I (DHTS, <b>1</b>) prevents the association of HuR with its RNA substrate, thus imparing its function. Herein, inspired by DHTS structure, we designed and synthesized an array of ortho-quinones (tanshinone mimics) using a function-oriented synthetic approach. Among others, compound <b>6a</b> and <b>6n</b> turned out to be more effective than <b>1</b>, showing a nanomolar <i>K</i><sub>i</sub> and disrupting HuR binding to RNA in cells. A combined approach of NMR titration and molecular dynamics (MD) simulations suggests that <b>6a</b> stabilizes HuR in a peculiar closed conformation, which is incompatible with RNA binding. Alpha screen and RNA-electrophoretic mobility shift assays (REMSA) data on newly synthesized compounds allowed, for the first time, the generation of structure activity relationships (SARs), thus providing a solid background for the generation of highly effective HuR disruptors

    Interfering with HuR–RNA Interaction: Design, Synthesis and Biological Characterization of Tanshinone Mimics as Novel, Effective HuR Inhibitors

    Get PDF
    The human antigen R (HuR) is an RNA-binding protein known to modulate the expression of target mRNA coding for proteins involved in inflammation, tumorigenesis, and stress responses and is a valuable drug target. We previously found that dihydrotanshinone-I (DHTS, <b>1</b>) prevents the association of HuR with its RNA substrate, thus imparing its function. Herein, inspired by DHTS structure, we designed and synthesized an array of ortho-quinones (tanshinone mimics) using a function-oriented synthetic approach. Among others, compound <b>6a</b> and <b>6n</b> turned out to be more effective than <b>1</b>, showing a nanomolar <i>K</i><sub>i</sub> and disrupting HuR binding to RNA in cells. A combined approach of NMR titration and molecular dynamics (MD) simulations suggests that <b>6a</b> stabilizes HuR in a peculiar closed conformation, which is incompatible with RNA binding. Alpha screen and RNA-electrophoretic mobility shift assays (REMSA) data on newly synthesized compounds allowed, for the first time, the generation of structure activity relationships (SARs), thus providing a solid background for the generation of highly effective HuR disruptors
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