Effects of MPP+ on the molecular pathways involved in cell cycle control in B65 neuroblastoma cells.
The toxicity caused by cell exposure to 1-methyl-4-phenylpyridinium ion (MPP(+)) is a useful model in the study of Parkinson's disease (PD). However, the exact molecular mechanisms triggered by MPP(+) in cell death are currently unclear. In the present research, we show that exposure to MPP(+) induce the cell death of neuroblastoma-derived dopaminergic B65 cells, which is not reversed by the widely known caspase inhibitor Z-VAD fmk or by calpain inhibition. Likewise, when B65 cells were treated with MPP(+), the DNA damage pathway that involves p53 was activated, and cells were arrested in the G(2)/M phase of the cell cycle. Interestingly, MPP(+) has two effects on the expression of cell cycle-related proteins. It increases the content of cyclins A, E, cdk2 and the phosphorylated form of pRb (serine 780). However, MPP(+) 5mM decreased the expression of cyclin D1, B1 and cdk4. The decrease in the expression of cyclin B1 may be related to the arrest of cells observed in the G(2)/M phase of cell cycle. The increase in S phase cell cycle proteins and retinoblastoma protein phosphorylation was an unexpected result. As the antioxidant trolox attenuated the process of cell loss and changes in the cell cycle, as measured by flow cytometry, we concluded that oxidative stress was involved in the effects of MPP(+) in this cell line. In summary, the present work characterizes the molecular changes involved in damage caused by MPP(+) in B65 cells, and highlights the effects of MPP(+) on molecules involved in the control of cell cycle progression.
Pizarro
Javier G
JG
Unitat de Farmacologia i Farmacognòsia, Institut de Biomedicina (IBUB), Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Universitat de Barcelona, Nucli Universitari de Pedralbes, 08028 Barcelona, Spain.
Junyent
Felix
F
Verdaguer
Ester
E
Jordan
Joaquin
J
Beas-Zarate
Carlos
C
Pallàs
Mercè
M
Camins
Antoni
A
Folch
Jaume
J
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004249:DNA Damage; D053938:DNA Fragmentation / Q000187:drug effects; D015259:Dopamine Agents / Q000633:toxicity*; D005434:Flow Cytometry; D006657:Histones / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D009447:Neuroblastoma / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
D018797:Cell Cycle Proteins; D015853:Cysteine Proteinase Inhibitors; D015259:Dopamine Agents; C468783:H2AX protein, human; D006657:Histones; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D053148:Caspase 3; D015655:1-Methyl-4-phenylpyridinium