Genetic inactivation or pharmacological inhibition of Pdk1 delays development and inhibits metastasis of Braf V600E::Pten -/- melanoma

M. Scortegagna, C. Ruller, Y. Feng, R. Lazova, H. Kluger, J. L. Li, S. K. De, R. Rickert, M. Pellecchia, M. Bosenberg, Z. A. Ronai

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Phosphoinositide-dependent kinase-1 (PDK1) is a serine/threonine protein kinase that phosphorylates members of the conserved AGC kinase superfamily, including AKT and protein kinase C (PKC), and is implicated in important cellular processes including survival, metabolism and tumorigenesis. In large cohorts of nevi and melanoma samples, PDK1 expression was significantly higher in primary melanoma, compared with nevi, and was further increased in metastatic melanoma. PDK1 expression suffices for its activity, owing to auto-activation, or elevated phosphorylation by phosphoinositide 3′-OH-kinase (PI3K). Selective inactivation of Pdk1 in the melanocytes of Braf V600E::Pten -/- or Braf V600E::Cdkn2a -/-::Pten -/- mice delayed the development of pigmented lesions and melanoma induced by systemic or local administration of 4-hydroxytamoxifen. Melanoma invasion and metastasis were significantly reduced or completely prevented by Pdk1 deletion. Administration of the PDK1 inhibitor GSK2334470 (PDKi) effectively delayed melanomagenesis and metastasis in Braf V600E::Pten -/- mice. Pdk1 -/- melanomas exhibit a marked decrease in the activity of AKT, P70S6K and PKC. Notably, PDKi was as effective in inhibiting AGC kinases and colony forming efficiency of melanoma with Pten wild-type (WT) genotypes. Gene expression analyses identified Pdk1-dependent changes in FOXO3a-regulated genes, and inhibition of FOXO3a restored proliferation and colony formation of Pdk1 -/- melanoma cells. Our studies provide direct genetic evidence for the importance of PDK1, in part through FOXO3a-dependent pathway, in melanoma development and progression.

Original languageEnglish
Pages (from-to)4330-4339
Number of pages10
JournalOncogene
Volume33
Issue number34
DOIs
StatePublished - 21 Aug 2014
Externally publishedYes

Keywords

  • Braf
  • FOXO3a
  • GSK2334470
  • PDK1
  • Pten
  • melanoma

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