Resumé
Methods: We have used siRNA optimized for inhibition of p53, PPP1R13L, BAX and GADD45 alpha expression and investigated the role of those gene products for PPP1R13L expression and induction in a variety of mouse and human cells with different p53 status. In addition we have applied Western Blot, Q-PCR and proteasome inhibition analysis to further ascertain the link between PPP1R13L induction and p53 status.
Results: We show that the pattern and extent of the PPP1R13L expression depend on the presence of active p53. Downregulation of p53 target genes BAX and/or GADD45 alpha led to decreased in PPP1R13L activation after adriamycin and/or etoposide treatments. Treatment of the cells with the proteasome inhibitor MG-132 resulted in the accumulation of both p53 and PPP1R13L proteins.
Conclusions: We have provided evidence that endogenous PPP1R13L acts as a negative regulator of p53 function, presumably by direct binding. p53 accumulation and activity after DNA damage is compromised by PPP1R13L expression. We suggest that PPP1R13L and p53 form a negative feedback loop which regulates their amount and activity.
General significance: The profound modulatory effect of the PPP1R13L protein on the ability of p53 to cause
cellular apoptosis has important implications in cancer and presents new therapeutic possibilities.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Biochimica et Biophysica Acta - General Subjects |
| Vol/bind | 1800 |
| Udgave nummer | 12 |
| Sider (fra-til) | 1231-1240 |
| ISSN | 0304-4165 |
| DOI | |
| Status | Udgivet - 2010 |
Citer dette
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p53 and PPP1R13L (alias iASPP or RAI) form a feedback loop to regulate genotoxic stress responses. / Laske, Magdalena J.; Vogel, Ulla; Jensen, Uffe B.; Nexø, Bjørn A.
I: Biochimica et Biophysica Acta - General Subjects, Bind 1800, Nr. 12, 2010, s. 1231-1240.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
TY - JOUR
T1 - p53 and PPP1R13L (alias iASPP or RAI) form a feedback loop to regulate genotoxic stress responses
AU - Laske, Magdalena J.
AU - Vogel, Ulla
AU - Jensen, Uffe B.
AU - Nexø, Bjørn A.
PY - 2010
Y1 - 2010
N2 - Background: PPP1R13L gene has been found to be over-expressed in variety of cancers and its expression in p53 wild-type background is sufficient to promote tumor growth in vivo. However, in the non-transformed cells it acts as a tumor suppressor which suggests that the role of PPP1R13L is multifaceted. Methods: We have used siRNA optimized for inhibition of p53, PPP1R13L, BAX and GADD45 alpha expression and investigated the role of those gene products for PPP1R13L expression and induction in a variety of mouse and human cells with different p53 status. In addition we have applied Western Blot, Q-PCR and proteasome inhibition analysis to further ascertain the link between PPP1R13L induction and p53 status. Results: We show that the pattern and extent of the PPP1R13L expression depend on the presence of active p53. Downregulation of p53 target genes BAX and/or GADD45 alpha led to decreased in PPP1R13L activation after adriamycin and/or etoposide treatments. Treatment of the cells with the proteasome inhibitor MG-132 resulted in the accumulation of both p53 and PPP1R13L proteins. Conclusions: We have provided evidence that endogenous PPP1R13L acts as a negative regulator of p53 function, presumably by direct binding. p53 accumulation and activity after DNA damage is compromised by PPP1R13L expression. We suggest that PPP1R13L and p53 form a negative feedback loop which regulates their amount and activity. General significance: The profound modulatory effect of the PPP1R13L protein on the ability of p53 to cause cellular apoptosis has important implications in cancer and presents new therapeutic possibilities.
AB - Background: PPP1R13L gene has been found to be over-expressed in variety of cancers and its expression in p53 wild-type background is sufficient to promote tumor growth in vivo. However, in the non-transformed cells it acts as a tumor suppressor which suggests that the role of PPP1R13L is multifaceted. Methods: We have used siRNA optimized for inhibition of p53, PPP1R13L, BAX and GADD45 alpha expression and investigated the role of those gene products for PPP1R13L expression and induction in a variety of mouse and human cells with different p53 status. In addition we have applied Western Blot, Q-PCR and proteasome inhibition analysis to further ascertain the link between PPP1R13L induction and p53 status. Results: We show that the pattern and extent of the PPP1R13L expression depend on the presence of active p53. Downregulation of p53 target genes BAX and/or GADD45 alpha led to decreased in PPP1R13L activation after adriamycin and/or etoposide treatments. Treatment of the cells with the proteasome inhibitor MG-132 resulted in the accumulation of both p53 and PPP1R13L proteins. Conclusions: We have provided evidence that endogenous PPP1R13L acts as a negative regulator of p53 function, presumably by direct binding. p53 accumulation and activity after DNA damage is compromised by PPP1R13L expression. We suggest that PPP1R13L and p53 form a negative feedback loop which regulates their amount and activity. General significance: The profound modulatory effect of the PPP1R13L protein on the ability of p53 to cause cellular apoptosis has important implications in cancer and presents new therapeutic possibilities.
KW - DNA damage
KW - p53 tumor suppressor
KW - PPP1R13L
KW - Apoptosis
KW - Proteasome inhibitor
U2 - 10.1016/j.bbagen.2010.09.002
DO - 10.1016/j.bbagen.2010.09.002
M3 - Journal article
VL - 1800
SP - 1231
EP - 1240
JO - B B A - General Subjects
JF - B B A - General Subjects
SN - 0304-4165
IS - 12
ER -