Differential expression of S6K2 dictates tissue-specific requirement for S6K1 in mediating aberrant mTORC1 signaling and tumorigenesis.

TitleDifferential expression of S6K2 dictates tissue-specific requirement for S6K1 in mediating aberrant mTORC1 signaling and tumorigenesis.
Publication TypeJournal Article
Year of Publication2011
AuthorsNardella C, Lunardi A, Fedele G, Clohessy JG, Alimonti A, Kozma SC, Thomas G, Loda M, Pandolfi PPaolo
JournalCancer Res
Volume71
Issue10
Pagination3669-75
Date Published2011 May 15
ISSN1538-7445
KeywordsAnimals, Cell Line, Tumor, Gene Deletion, Gene Expression Profiling, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Neoplastic, Heterozygote, Humans, Mechanistic Target of Rapamycin Complex 1, Mice, Mice, Transgenic, Multiprotein Complexes, Pheochromocytoma, Proteins, Ribosomal Protein S6 Kinases, 70-kDa, TOR Serine-Threonine Kinases
Abstract

The S6K1 and S6K2 kinases are considered important mTOR signaling effectors, yet their contribution to tumorigenesis remains unclear. Aberrant mTOR activation is a frequent event in cancer that commonly results from heterozygous loss of PTEN. Here, we show for the first time a differential protein expression between S6K1 and S6K2 in both mouse and human tissues. Additionally, the inactivation of S6k1 in the context of Pten heterozygosity (Pten(+/-)) suggests a differential requirement for this protein across multiple tissues. This tissue specificity appears to be governed by the relative protein expression of S6k2. Accordingly, we find that deletion of S6k1 markedly impairs Pten(+/-) mediated adrenal tumorigenesis, specifically due to low expression of S6k2. Concomitant observation of low S6K2 levels in the human adrenal gland supports the development of S6K1 inhibitors for treatment of PTEN loss-driven pheochromocytoma.

DOI10.1158/0008-5472.CAN-10-3962
Alternate JournalCancer Res
PubMed ID21444676
Grant List5U01CA141464-02 / CA / NCI NIH HHS / United States
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