Inhibition of autophagy enhances the effects of the AKT inhibitor MK-2206 when combined with paclitaxel and carboplatin in BRAF wild-type melanoma

Vito W. Rebecca, Renato R. Massaro, Inna V. Fedorenko, Vernon K. Sondak, Alexander R.A. Anderson, Eunjung Kim, Ravi K. Amaravadi, Silvya S. Maria-Engler, Jane L. Messina, Geoffrey T. Gibney, Ragini R. Kudchadkar, Keiran S.M. Smalley

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

This study investigates the mechanism of action behind the long-term responses (12-16 months) of two BRAF WT melanoma patients to the AKT inhibitor MK-2206 in combination with paclitaxel and carboplatin. Although single agent MK-2206 inhibited phospho-AKT signaling, it did not impact in vitro melanoma growth or survival. The combination of MK-2206 with paclitaxel and carboplatin was cytotoxic in long-term colony formation and 3D spheroid assays, and induced autophagy. Autophagy was initially protective with autophagy inhibitors and deletion of ATG5 found to enhance cytotoxicity. Although prolonged autophagy induction (>6 days) led to caspase-dependent apoptosis, drug resistant clones still emerged. Autophagy inhibition enhanced the cell death response through reactive oxygen species and could be reversed by anti-oxidants. We demonstrate for the first time that AKT inhibition in combination with chemotherapy may have clinical activity in BRAF WT melanoma and show that an autophagy inhibitor may prevent resistance to these drugs.

Original languageEnglish (US)
Pages (from-to)465-478
Number of pages14
JournalPigment Cell and Melanoma Research
Volume27
Issue number3
DOIs
StatePublished - May 2014
Externally publishedYes

Keywords

  • AKT
  • Apoptosis
  • Autophagy
  • BRAF
  • Chemotherapy
  • Melanoma

ASJC Scopus subject areas

  • Oncology
  • General Biochemistry, Genetics and Molecular Biology
  • Dermatology

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