RESUMEN
The potential of erythropoietin (EPO) to reduce hypoxia-induced cell death has been investigated in 5-day-old primary cultures of rat postnatal hippocampal neurons. Application of EPO (100 pM) at the start of hypoxia resulted in a significant reduction of neuronal death (33.0 +/- 7.5% in cells incubated with EPO vs 56.75 +/- 7.3% in non-treated cells; n = 4, p < 0.021). Similiar results were obtained upon application of cycloheximide (CHX; 1 microM) simultaneously with hypoxia (34.75 +/- 5.6% vs 56.75 +/- 7.3% with and without CHX, respectively, n = 4, p < 0.035), indicating that hypoxia-induced neuronal death is an active, protein synthesis-dependent process. Both, EPO and EPO receptor (EPOR) were found to be expressed after hypoxia in hippocampal neurons in vitro and in vivo. These results demonstrate for the first time that EPO can reverse hypoxia-induced neuronal death when applied simultaneously with the hypoxic stimulus.
Asunto(s)
Hipoxia de la Célula/fisiología , Supervivencia Celular/fisiología , Eritropoyetina/farmacología , Hipocampo/citología , Neuronas/citología , Receptores de Eritropoyetina/fisiología , Animales , Animales Recién Nacidos , Hipoxia de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Cicloheximida/farmacología , Eritropoyetina/genética , Factor 2 de Crecimiento de Fibroblastos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Neuronas/efectos de los fármacos , Neuronas/fisiología , Ratas , Ratas Wistar , Receptores de Eritropoyetina/genética , Proteínas Recombinantes , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transcripción Genética/efectos de los fármacosRESUMEN
We as well as others have recently shown that Hsp90 is overexpressed in multiple myeloma (MM) and critically contributes to tumour cell survival. Pharmacologic blockade of Hsp90 has consistently been found to induce MM cell death. However, most data have been obtained with MM cell lines whereas knowledge about the molecular effects of pharmacologic Hsp90 blockade in primary tumour cells is limited. Furthermore, these investigations have so far focused on geldanamycin derivatives. We analysed the biochemical effects of a novel diarylisoxazole-based Hsp90 inhibitor (NVP-AUY922) on signalling pathways and cell death in a large set of primary MM tumour samples and in MM cell lines. Treated cells displayed the molecular signature and pharmacodynamic properties for abrogation of Hsp90 function, such as downregulation of multiple survival pathways and strong upregulation of Hsp70. NVP-AUY922 treatment efficiently induced MM cell apoptosis and revealed both sensitive and resistant subgroups. Sensitivity was not correlated with TP53 mutation or Hsp70 induction levels and stromal cells from the bone marrow microenvironment were unable to abrogate NVP-AUY922-induced apoptosis of MM cells. Thus, NVP-AUY922 may be a promising drug for treatment of MM and clinical studies are warranted.