title: Apoptosis induced by paclitaxel via Bcl-2, Bax and caspases 3 and 9 activation in NB4 human leukaemia cells is not modulated by ERK inhibition.
abstract: We have studied the role of pivotal bio-molecules involved in signalling of cytotoxic effects induced by paclitaxel (Ptx) on acute promyelocytic human leukaemia NB4 cells. A time-dependent increase in cell death and DNA cleavage was observed after 30μM Ptx treatment. Cell death induction by Ptx proceeds mainly as programmed cell death as shown by annexin V-FITC, reaching up to 30% of apoptotic cells after 24h. Significant reductions of p53, changes in Bax and Bcl-2 and activation of caspases 3 and 9 were observed as the treatment was applied for long times. Ptx treatments produced NFkB depletion with expression levels abolished at 19h what could be involved in reduction of survival signals. Phosphorylation of intracellular kinases showed that pERK1/2 decreased significantly at 19h of Ptx treatment. When these cells were preincubated for 90min with 20μM PD98059, 2'-amino-3'-methoxyflavone, an inhibitor of ERK phosphorylation, a slight reduction of cell viability was observed in comparison to that produced by Ptx alone. Pretreatment with PD98059 neither activated caspases nor significantly increased the apoptotic effect of Ptx. Taken together, our data reveal that the inhibition of ERK phosphorylation does not seem to be an essential pathway for bursting an increased induction of apoptosis by Ptx. Decrease of p53 and Bcl-2, fragmentation of DNA, increase of Bax and, finally, activation of caspases 3 and 9 in NB4 leukaemia cells make the apoptotic process induced by Ptx irreversible. Application of Ptx in leukaemia cells shows therefore a promising potential with particular effects on different leukaemia cell types.
authors.affiliation: Bioquímica y Biología Molecular, Facultad de Medicina, Campus Universitario, Universidad de Alcalá, 28871 Alcalá de Henares (Madrid), Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Morales-Cano
authors.forename: Eva
authors.initials: E
authors.lastname: Calviño
authors.forename: Virginia
authors.initials: V
authors.lastname: Rubio
authors.forename: Angel
authors.initials: A
authors.lastname: Herráez
authors.forename: Pilar
authors.initials: P
authors.lastname: Sancho
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Tejedor
authors.forename: José C
authors.initials: JC
authors.lastname: Diez
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007938:Leukemia / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D048049:Extracellular Signal-Regulated MAP Kinases; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D017239:Paclitaxel
keywords: Apoptosis; Bax; Bcl-2; Caspases; Kinases; Leukaemia; p53