RESUMEN
Naphthalimmide (NI) and 1,4,5,8-naphthalentetracarboxylic diimide (NDI) derivatives were synthesized and evaluated for their antiproliferative activity. NDI derivatives 1-9 were more cytotoxic than the corresponding NI derivatives 10-18. The molecular mechanisms of 1 and 2 were investigated in comparison to mitonafide. They interacted with DNA, were not topoisomerase IIalpha poisons, triggered caspase activation, caused p53 protein accumulation, and down-regulated AKT survival. Furthermore, 1 and 2 caused a decrease of ERK1/2 and, unlike mitonafide, inhibited ERKs phosphorylation.
Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Imidas/química , Imidas/farmacología , Naftalenos/química , Antineoplásicos/metabolismo , Antineoplásicos/toxicidad , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , ADN/metabolismo , Diseño de Fármacos , Humanos , Imidas/metabolismo , Imidas/toxicidad , Inhibidores de TopoisomerasaRESUMEN
Extracellular signal-regulated kinase (ERK) controls fundamental cellular functions, including cell fate decisions. In PC12, cells shifting ERK activation from transient to sustained induces neuronal differentiation. As ERK associates with both regulators and effectors, we hypothesized that the mechanisms underlying the switch could be revealed by assessing the dynamic changes in ERK-interacting proteins that specifically occur under differentiation conditions. Using quantitative proteomics, we identified 284 ERK-interacting proteins. Upon induction of differentiation, 60 proteins changed their binding to ERK, including many proteins that were not known to participate in differentiation. We functionally characterized a subset, showing that they regulate the pathway at several levels and by different mechanisms, including signal duration, ERK localization, feedback, crosstalk with the Akt pathway and differential interaction and phosphorylation of transcription factors. Integrating these data with a mathematical model confirmed that ERK dynamics and differentiation are regulated by distributed control mechanisms rather than by a single master switch.
Asunto(s)
Linaje de la Célula , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Sistema de Señalización de MAP Quinasas , Animales , Modelos Biológicos , Células PC12 , Unión Proteica , Proteómica , RatasRESUMEN
Vinorelbine (VNR) is a semi-synthetic vinca alkaloid known to exert its antitumour activity by interfering with the polymerisation of tubulin. It has shown a broad spectrum of activity in some advanced carcinomas of lung, breast and ovary. This report demonstrates for the first time the antiproliferative effect of VNR and its molecular mechanism in human osteosarcoma in vitro. TP53 wild-type HOS cells and TP53 mutated MG-63 cells were chosen for this study. In each cell line, VNR caused a significant dose- and time-dependent growth inhibition and induced apoptotic death independent of TP53 status. Phosphorylation and/or alteration of Bcl-2 were not induced by VNR, thereby indicating a new pathway utilised by the drug to induce apoptosis in this tumour in vitro. VNR produced a down-regulation of cyclin D1 and an up-regulation of p53 expression in TP53 wild-type HOS cells, whereas no alteration in cyclin D1 expression was evident in the TP53 negative MG-63 cells. These data suggest a new potential use for Vinorelbine as a therapeutic agent against human osteosarcoma.
Asunto(s)
Antineoplásicos Fitogénicos/uso terapéutico , Neoplasias Óseas/tratamiento farmacológico , Osteosarcoma/tratamiento farmacológico , Vinblastina/análogos & derivados , Antineoplásicos Fitogénicos/farmacología , Apoptosis , Neoplasias Óseas/genética , Neoplasias Óseas/metabolismo , Proliferación Celular/efectos de los fármacos , Ciclina D1/metabolismo , Regulación hacia Abajo , Humanos , Osteosarcoma/genética , Osteosarcoma/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Vinblastina/farmacología , Vinblastina/uso terapéutico , Vinorelbina , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Genetic alterations on chromosome 17p are frequent in a variety of human malignancies such as sporadic breast carcinomas. The clinico-pathological significance of it remains to be elucidated. The purpose of this study was to explore whether the allelic loss (LOH) in 17p13.3, which is suggested by the presence of tumour suppressor genes, independent of TP53, are related to current clinico-pathological criteria for characterising breast cancer. A group of sporadic breast carcinomas, with no alteration in TP53 locus, were analysed for the presence of LOH in D17S34 and D17S30/5 loci, mapped to the 17p13.3 region, distinct from and telomeric to TP53. LOH by at least one marker was observed in 13 of 47 informative cases (27.6%). Clinicopathological parameters such as age, menopausal status, histological type, tumour size, nodal status, grading, ploidy, labelling index, S-phase fraction and hormonal phenotype, were evaluated. LOH at distal 17p13.3 significantly correlated with the absence of oestrogen receptors (ER) (P=0.018), progesterone receptors (PgR) (P=0.009) and concordant absence of either ER or PgR (P=0.006). This may provide a basis for speculation as to the function of the putative tumour suppressor genes in 17p13-ter in sporadic breast cancer.
Asunto(s)
Neoplasias de la Mama/patología , Cromosomas Humanos Par 17/genética , Pérdida de Heterocigocidad , Proteína p53 Supresora de Tumor/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , ADN de Neoplasias/análisis , ADN de Neoplasias/genética , Femenino , Humanos , Repeticiones de Microsatélite , Persona de Mediana Edad , Fenotipo , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Polimorfismo Conformacional Retorcido-Simple , Receptores de Estrógenos/análisis , Receptores de Progesterona/análisis , Telómero/genéticaRESUMEN
The single-chain ribosome-inactivating proteins (RIPs) from plant origin, including Saporin 6 from the seeds of Saponaria officinalis, are ribotoxins known to act as N-glycosidases which depurinate the conserved alpha sarcin loop of large rRNAs. As a consequence, the eukaryotic ribosomes become inactivated, thereby arresting the protein synthesis at the elongation step. RIPs are currently under study as antiviral and antiproliferative agents. Additional in vitro activities of RIPs against either RNA or DNA have been recently described. A specific nuclease activity on plasmidic DNA was demonstrated by either purified or bacterial-recombinant molecules. We report here that human mitochondrial DNA (mtDNA) is a new specific target of Saporin 6 nuclease activity. A unique site of cleavage has been identified and mapped within the most variable part of the D-loop region of the covalently closed circular mtDNA molecule.
Asunto(s)
ADN Mitocondrial/efectos de los fármacos , Inmunotoxinas/toxicidad , N-Glicosil Hidrolasas/toxicidad , Proteínas de Plantas/toxicidad , Southern Blotting , Enzimas de Restricción del ADN/metabolismo , ADN Mitocondrial/metabolismo , Humanos , Mapeo Restrictivo , Proteínas Inactivadoras de Ribosomas Tipo 1 , SaporinasRESUMEN
Cholesterol esterification by acyl-CoA:cholesterol acyltransferase (ACAT) and proliferation of vascular smooth muscle cells (VSMC) are key events in vascular proliferative diseases. Here we performed experiments to ascertain the role of cholesterol ester pathway in the control of human aortic VSMC cycle progression. Results showed that serum-induced VSMC proliferation was preceded by an increased ability of the cells to esterify cholesterol as well as by an increased expression of ACAT and multidrug resistance (MDR1) mRNAs and extracellular related kinases 1/2 (ERK1/2), whereas caveolin-1 levels were markedly decreased. Cell cycle analyses performed in the presence of two inhibitors of cholesterol esterification, directly inhibiting ACAT (Sandoz 58-035) or the transport of cholesterol substrate from plasma membrane to endoplasmic reticulum (progesterone), indicate that each inhibitor suppressed the serum-induced DNA synthesis by accumulation of VSMCs in the G1 phase. The effect was associated with a rapid inhibition of ERK1/2 mitogenic signaling pathway; a down-regulation of cyclin D1, ACAT, and MDR1 mRNA; and an up-regulation of caveolin-1. These data provide a plausible link between cholesterol esterification and control of cell cycle G1/S transition, supporting the hypothesis that cholesterol esterification may accelerate the progression of human vascular proliferative diseases by modulating the rate of the VSMC proliferation.