RESUMEN
We identified mutations in the IL7Ra gene or in genes encoding the downstream signaling molecules JAK1, JAK3, STAT5B, N-RAS, K-RAS, NF1, AKT and PTEN in 49% of patients with pediatric T-cell acute lymphoblastic leukemia (T-ALL). Strikingly, these mutations (except RAS/NF1) were mutually exclusive, suggesting that they each cause the aberrant activation of a common downstream target. Expressing these mutant signaling molecules-but not their wild-type counterparts-rendered Ba/F3 cells independent of IL3 by activating the RAS-MEK-ERK and PI3K-AKT pathways. Interestingly, cells expressing either IL7Ra or JAK mutants are sensitive to JAK inhibitors, but respond less robustly to inhibitors of the downstream RAS-MEK-ERK and PI3K-AKT-mTOR pathways, indicating that inhibiting only one downstream pathway is not sufficient. Here, we show that inhibiting both the MEK and PI3K-AKT pathways synergistically prevents the proliferation of BaF3 cells expressing mutant IL7Ra, JAK and RAS. Furthermore, combined inhibition of MEK and PI3K/AKT was cytotoxic to samples obtained from 6 out of 11 primary T-ALL patients, including 1 patient who had no mutations in the IL7R signaling pathway. Taken together, these results suggest that the potent cytotoxic effects of inhibiting both MEK and PI3K/AKT should be investigated further as a therapeutic option using leukemia xenograft models.
Asunto(s)
Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Inhibidores de las Quinasa Fosfoinosítidos-3 , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Receptores de Interleucina-7/metabolismo , Transducción de Señal/efectos de los fármacos , Animales , Proliferación Celular/efectos de los fármacos , Humanos , Ratones , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patología , Inhibidores de Proteínas Quinasas/farmacología , Receptores de Interleucina-7/antagonistas & inhibidores , Transfección , Células Tumorales CultivadasRESUMEN
BACKGROUND: Triple-negative breast cancers (TNBC) are considered the most aggressive type of breast cancer, for which no targeted therapy exists at the moment. These tumors are characterized by having a high degree of chromosome instability and often overexpress the spindle assembly checkpoint kinase TTK. To explore the potential of TTK inhibition as a targeted therapy in TNBC, we developed a highly potent and selective small molecule inhibitor of TTK, NTRC 0066-0. RESULTS AND CONCLUSIONS: The compound is characterized by long residence time on the target and inhibits the proliferation of a wide variety of human cancer cell lines with potency in the same range as marketed cytotoxic agents. In cell lines and in mice, NTRC 0066-0 inhibits the phosphorylation of a TTK substrate and induces chromosome missegregation. NTRC 0066-0 inhibits tumor growth in MDA-MB-231 xenografts as a single agent after oral application. To address the effect of the inhibitor in breast cancer, we used a well-defined mouse model that spontaneously develops breast tumors that share key morphologic and molecular features with human TNBC. Our studies show that combination of NTRC 0066-0 with a therapeutic dose of docetaxel resulted in doubling of mouse survival and extended tumor remission, without toxicity. Furthermore, we observed that treatment efficacy is only achieved upon co-administration of the two compounds, which suggests a synergistic in vivo effect. Therefore, we propose TTK inhibition as a novel therapeutic target for neoadjuvant therapy in TNBC.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Proteínas de Ciclo Celular/antagonistas & inhibidores , Proliferación Celular/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Taxoides/farmacología , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Animales , Modelos Animales de Enfermedad , Docetaxel , Quimioterapia Combinada , Femenino , Citometría de Flujo , Células HeLa , Humanos , Técnicas para Inmunoenzimas , Ratones , Estructura Molecular , Tasa de Supervivencia , Neoplasias de la Mama Triple Negativas/mortalidad , Neoplasias de la Mama Triple Negativas/patología , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
[reaction--see text] Ionic liquid 1-butyl-3-methylimidazoliumhexafluorophosphate ([bmim]PF(6)) is described as an effective medium for ring-closing metathesis (RCM) using Grubbs catalysts. When [bmim]PF(6) was used as solvent, the RCM showed high conversions and a broad substrate tolerance. [bmim]PF(6) and the ruthenium catalyst were recycled after extraction of the product in the organic phase for at least three cycles.
RESUMEN
The synthesis of three heparin analogues (i.e. compounds VI-VIII) having perphosphorylated thrombin binding domains (TBDs) is reported. These compounds were tested in vitro for their antithrombin III (ATIII)-mediated anti-Xa and antithrombin activities. Conjugates VI and VIII show a remarkable increase in antithrombin activity compared to the structurally related conjugates with persulfated TBDs (i.e. compounds IV and V), whereas compound VII displays a diminished activity.
Asunto(s)
Antitrombinas/síntesis química , Heparina/análogos & derivados , Trombina/metabolismo , Antitrombinas/química , Antitrombinas/metabolismo , Sitios de Unión , Conformación de Carbohidratos , Secuencia de Carbohidratos , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Datos de Secuencia Molecular , FosforilaciónRESUMEN
The synthesis of a novel antithrombotic consisting of a heparin pentasaccharide conjugated to the active site inhibitor N-(2-naphtalenesulfonyl)-glycyl-(D)-4-aminophenyl-alanyl-piperidin e (NAPAP) (i.e. compound I) is reported. This conjugate shows a unique pharmacological profile both in vitro and in vivo having direct anti-thrombin and ATIII-mediated anti-Xa activity. Furthermore, conjugate I has a prolonged in vivo half-life compared to NAPAP (1.5 h vs 9 min.).