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PKC and Raf‐1 inhibition‐related apoptotic signalling in N2a cells
Author(s) -
Bronisz Agnieszka,
Gajkowska Barbara,
Doma Krystyna,
SkaJanik ń
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2002.00896.x
Subject(s) - staurosporine , protein kinase b , wortmannin , apoptosis , protein kinase c , phosphorylation , microbiology and biotechnology , biology , pi3k/akt/mtor pathway , programmed cell death , cytosol , signal transduction , cell culture , cancer research , biochemistry , enzyme , genetics
In this study, a neuroblastoma N2a cell line was applied to investigate mechanisms of apoptosis induced either by selective inhibition of protein kinase C (PKC) by low amounts of staurosporine (STS 10 ) or by inhibition PI3‐K after wortmannin (WM) treatment. We present evidence that, in the absence of serum in the medium, decreased phosphorylation of Raf‐1 and BAD 112 , as well as Akt and BAD 136 , proteins and their translocation to mitochondria coincided with STS 10 ‐ or WM‐induced apoptosis, respectively. Concomitantly, release of cytochrome c into the cytosol indicated a BCL‐2‐dependent mode of cell death after both treatments. Furthermore, in typical ‘gain of function’ experiments, cells with overexpression of permanently active Raf‐1 or Akt transgenes displayed a significantly higher and independent resistance to either STS 10 or WM. Thus, our results indicate that PKC/Raf‐1/BAD 112 , as well as PI3‐K/Akt/BAD 136 signalling pathways, are both necessary for N2a cell survival and thus are unable to functionally substitute for each other as long as the cells do not receive additional signal(s) derived from serum. However, in the presence of serum, undefined trophic signal(s) can stimulate cross‐talk between these two pathways at a level upstream from Raf‐1 and Akt phosphorylation. In this case, only simultaneous inhibition of PKC and PI3‐K is able to induce apoptosis.