This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Edwards, A. Articles by Haura, E. B. Search for Related Content PubMed PubMed Citation Articles by Edwards, A. Articles by Haura, E. B.

Research Articles: Therapeutics, Targets, and Development

Effect of the histone deacetylase inhibitor LBH589 against epidermal growth factor receptor–dependent human lung cancer cells

¹ Thoracic Oncology and Experimental Therapeutics Programs, H. Lee Moffitt Cancer Center and Research Institute; ² Department of Interdisciplinary Oncology, University of South Florida College of Medicine, Tampa, Florida; ³ Novartis Pharmaceutical, Inc., Cambridge, Massachusetts; and ⁴ Medical College of Georgia Cancer Center, Augusta, Georgia

Requests for reprints: Eric B. Haura, Thoracic Oncology and Experimental Therapeutics Programs, H. Lee Moffitt Cancer Center and Research Institute, MRC3 East, Room 3056, 12902 Magnolia Drive, Tampa, FL 33612-9497. Phone: 813-903-6826; Fax: 813-903-6817. E-mail: eric.haura{at}moffitt.org

Abstract

Activating mutations in the epidermal growth factor receptor (EGFR) selectively activate signal transducers and activators of transcription (STAT) and Akt survival signaling pathways important in lung cancer cell growth and survival. Many kinases, such as EGFR, rely on heat shock protein 90 (Hsp90) chaperone function for conformational maturation and proper function. Histone deacetylase inhibitors (HDACi) have been suggested to regulate signaling protein interactions via modulation of protein chaperone function through Hsp90. For these reasons, we evaluated the effect of a HDACi in lung cancer cells with defined EGFR status. Cell lines with defined EGFR status and sensitivity to EGFR tyrosine kinase inhibitors were exposed to the HDACi LBH589, and the effects on cell survival, proliferation, and downstream signaling were evaluated. LBH589 resulted in increased acetylation of Hsp90 and reduced association of Hsp90 with EGFR, Akt, and STAT3. LBH589 selectively depleted proteins important in signaling cascades in cell lines harboring EGFR kinase mutations, such as EGFR, STAT3, and Akt, and these cells underwent apoptosis following exposure to LBH589. In addition, we found depletion of STAT3-dependent survival proteins, including Bcl-xL, Mcl-1, and Bcl-2. Conversely, LBH589 had little effect on apoptosis in cells not dependent on EGFR for survival, no changes were identified in the expression of EGFR or other survival proteins, and the predominant effect was cell cycle arrest rather than apoptosis. A 10-fold increase in LBH589 was necessary to observe durable depletion of EGFR and Akt in cells not harboring EGFR mutation. Treatment of cells with erlotinib and LBH589 resulted in synergistic effects on lung cancer cells dependent on EGFR for growth and/or survival. Based on these results, LBH589 can acetylate Hsp90, deplete EGFR and other key survival signaling proteins, and trigger apoptosis only in lung cancer cells harboring EGFR mutations. Therefore, EGFR mutation status may be predictive of outcome with LBH589 and possibly other HDACi. [Mol Cancer Ther 2007;6(9):2515–24]

Grant support: Joan's Legacy (E.B. Haura); H. Lee Moffitt Cancer Center and Research Institute; and Molecular Imaging Core, Molecular Biology and Sequencing Core, and the Flow Cytometry Core at the H. Lee Moffitt Cancer Center and Research Institute.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Received 12/ 7/06; revised 5/17/07; accepted 7/ 5/07.

This article has been cited by other articles:

				P. A. Bunn Jr., E. B. Haura, and J. V. Heymach Emerging Therapies for Non-small Cell Lung Cancer ASCO Educational Book, January 1, 2008; 2008(1): e5 - e14. [Abstract] [Full Text] [PDF]