TY - JOUR
T1 - Sphingosine analogue drug FTY720 targets I2PP2A/SET and mediates lung tumour suppression via activation of PP2A-RIPK1-dependent necroptosis
AU - Saddoughi, Sahar A.
AU - Gencer, Salih
AU - Peterson, Yuri K.
AU - Ward, Katherine E.
AU - Mukhopadhyay, Archana
AU - Oaks, Joshua
AU - Bielawski, Jacek
AU - Szulc, Zdzislaw M.
AU - Thomas, Raquela J.
AU - Selvam, Shanmugam P.
AU - Senkal, Can E.
AU - Garrett-Mayer, Elizabeth
AU - De Palma, Ryan M.
AU - Fedarovich, Dzmitry
AU - Liu, Angen
AU - Habib, Amyn A.
AU - Stahelin, Robert V.
AU - Perrotti, Danilo
AU - Ogretmen, Besim
PY - 2013/1
Y1 - 2013/1
N2 - Mechanisms that alter protein phosphatase 2A (PP2A)-dependent lung tumour suppression via the I2PP2A/SET oncoprotein are unknown. We show here that the tumour suppressor ceramide binds I2PP2A/SET selectively in the nucleus and including its K209 and Y122 residues as determined by molecular modelling/simulations and site-directed mutagenesis. Because I2PP2A/SET was found overexpressed, whereas ceramide was downregulated in lung tumours, a sphingolipid analogue drug, FTY720, was identified to mimick ceramide for binding and targeting I2PP2A/SET, leading to PP2A reactivation, lung cancer cell death, and tumour suppression in vivo. Accordingly, while molecular targeting of I2PP2A/SET by stable knockdown prevented further tumour suppression by FTY720, reconstitution of WT-I2PP2A/SET expression restored this process. Mechanistically, targeting I2PP2A/SET by FTY720 mediated PP2A/RIPK1-dependent programmed necrosis (necroptosis), but not by apoptosis. The RIPK1 inhibitor necrostatin and knockdown or genetic loss of RIPK1 prevented growth inhibition by FTY720. Expression of WT- or death-domain-deleted (DDD)-RIPK1, but not the kinase-domain-deleted (KDD)-RIPK1, restored FTY720-mediated necroptosis in RIPK1-/- MEFs. Thus, these data suggest that targeting I2PP2A/SET by FTY720 suppresses lung tumour growth, at least in part, via PP2A activation and necroptosis mediated by the kinase domain of RIPK1.
AB - Mechanisms that alter protein phosphatase 2A (PP2A)-dependent lung tumour suppression via the I2PP2A/SET oncoprotein are unknown. We show here that the tumour suppressor ceramide binds I2PP2A/SET selectively in the nucleus and including its K209 and Y122 residues as determined by molecular modelling/simulations and site-directed mutagenesis. Because I2PP2A/SET was found overexpressed, whereas ceramide was downregulated in lung tumours, a sphingolipid analogue drug, FTY720, was identified to mimick ceramide for binding and targeting I2PP2A/SET, leading to PP2A reactivation, lung cancer cell death, and tumour suppression in vivo. Accordingly, while molecular targeting of I2PP2A/SET by stable knockdown prevented further tumour suppression by FTY720, reconstitution of WT-I2PP2A/SET expression restored this process. Mechanistically, targeting I2PP2A/SET by FTY720 mediated PP2A/RIPK1-dependent programmed necrosis (necroptosis), but not by apoptosis. The RIPK1 inhibitor necrostatin and knockdown or genetic loss of RIPK1 prevented growth inhibition by FTY720. Expression of WT- or death-domain-deleted (DDD)-RIPK1, but not the kinase-domain-deleted (KDD)-RIPK1, restored FTY720-mediated necroptosis in RIPK1-/- MEFs. Thus, these data suggest that targeting I2PP2A/SET by FTY720 suppresses lung tumour growth, at least in part, via PP2A activation and necroptosis mediated by the kinase domain of RIPK1.
KW - Ceramide
KW - FTY720
KW - Sphingolipids
KW - Sphingosine
KW - Sphingosine kinase 2
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UR - http://www.scopus.com/inward/citedby.url?scp=84871968824&partnerID=8YFLogxK
U2 - 10.1002/emmm.201201283
DO - 10.1002/emmm.201201283
M3 - Article
C2 - 23180565
AN - SCOPUS:84871968824
SN - 1757-4676
VL - 5
SP - 105
EP - 121
JO - EMBO Molecular Medicine
JF - EMBO Molecular Medicine
IS - 1
ER -