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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
2010-9-30
pubmed:databankReference
pubmed:abstractText
The malignant brain cancer medulloblastoma is characterized by mutations in Hedgehog (Hh) signaling pathway genes, which lead to constitutive activation of the G protein (heterotrimeric guanosine triphosphate-binding protein)-coupled receptor Smoothened (Smo). The Smo antagonist NVP-LDE225 inhibits Hh signaling and induces tumor regression in animal models of medulloblastoma. However, evidence of resistance was observed during the course of treatment. Molecular analysis of resistant tumors revealed several resistance mechanisms. We noted chromosomal amplification of Gli2, a downstream effector of Hh signaling, and, more rarely, point mutations in Smo that led to reactivated Hh signaling and restored tumor growth. Analysis of pathway gene expression signatures also, unexpectedly, identified up-regulation of phosphatidylinositol 3-kinase (PI3K) signaling in resistant tumors as another potential mechanism of resistance. Probing the relevance of increased PI3K signaling, we demonstrated that addition of the PI3K inhibitor NVP-BKM120 or the dual PI3K-mTOR (mammalian target of rapamycin) inhibitor NVP-BEZ235 to the initial treatment with the Smo antagonist markedly delayed the development of resistance. Our findings may be useful in informing treatment strategies for medulloblastoma.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1946-6242
pubmed:author
pubmed-author:AndersonDustin LDL, pubmed-author:BriggsKimberly JKJ, pubmed-author:BuonamiciSilviaS, pubmed-author:DorschMarionM, pubmed-author:FordjourPaulP, pubmed-author:García-EcheverríaCarlosC, pubmed-author:GreenJohnJ, pubmed-author:HohK WKW, pubmed-author:HsiaoKathyK, pubmed-author:KelleherJoseph FJF, pubmed-author:LengauerChristophC, pubmed-author:MairaSauveur-MichelSM, pubmed-author:MonahanJohn EJE, pubmed-author:MorrisseyMichaelM, pubmed-author:OspinaBeatrizB, pubmed-author:OstromLanceL, pubmed-author:PanShifengS, pubmed-author:PeukertStefanS, pubmed-author:SellersWilliam RWR, pubmed-author:TianGG, pubmed-author:VattayAnthonyA, pubmed-author:WangAnlaiA, pubmed-author:WarmuthMarkusM, pubmed-author:WatkinsD NeilDN, pubmed-author:WilliamsJulietJ, pubmed-author:YaoYung-maeYM, pubmed-author:YuQunyanQ, pubmed-author:YuanJingJ
pubmed:issnType
Electronic
pubmed:day
29
pubmed:volume
2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
51ra70
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Interfering with resistance to smoothened antagonists by inhibition of the PI3K pathway in medulloblastoma.
pubmed:affiliation
Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural