Potential Involvement of Calcineurin in Regulating the State of Differentiation and Apoptosis of HL-60 Cells During Methylprednisolone-Treatment.
To evaluate the role of calcineurin (protein phosphatase type 2B, PP2B) in methylprednisolone-induced differentiation and apoptosis of leukaemic cells, we have investigated the induction of apoptosis, calcineurin specific protein phosphatase activity and expression of regulatory and catalytic subunits of calcineurin and calmodulin after induction of HL-60 leukaemic cells with methylprednisolone. The cells underwent differentiation and apoptosis within 72 hours time period after methylprednisolone added to cell culture media. Before apoptosis occurred, the specific calcineurin enzyme activity revealed gradual increase during the differentiation process. However, immunoblots of catalytic and regulatory subunits of calcineurin showed no amplification in the amount of these cellular signaling mediators during methylprednisolone-induced differentiation and apoptosis but calmodulin expression gradually increased during the process. Significant increase in the specific calcineurin enzyme activity during differentiation and apoptosis might be crucial to the posttranslational modifications of calcineurin during methylprednisolone-induced differentiation.
Serdar Bedii
SB
Omay
Güray
G
Saydam
Hikmet Hakan
HH
Aydın
Nur
N
Selvi
Gülperi
G
Öktem
Ulus Ali
UA
Sanlı
Mahmut
M
Tobu
Filiz
F
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