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 Kiziltepe, T. Articles by Anderson, K. C. Search for Related Content PubMed PubMed Citation Articles by Kiziltepe, T. Articles by Anderson, K. C.

Research Articles: Therapeutics, Targets, and Development

5-Azacytidine, a DNA methyltransferase inhibitor, induces ATR-mediated DNA double-strand break responses, apoptosis, and synergistic cytotoxicity with doxorubicin and bortezomib against multiple myeloma cells

Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts

Requests for reprints: Kenneth C. Anderson, Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115. E-mail: kenneth_anderson{at}dfci.harvard.edu and Tanyel Kiziltepe, Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115. Phone: 617-632-6553. E-mail: tanyel_kiziltepe{at}dfci.harvard.edu

Abstract

In this study, we investigated the cytotoxicity of 5-azacytidine, a DNA methyltransferase inhibitor, against multiple myeloma (MM) cells, and characterized DNA damage–related mechanisms of cell death. 5-Azacytidine showed significant cytotoxicity against both conventional therapy-sensitive and therapy-resistant MM cell lines, as well as multidrug-resistant patient-derived MM cells, with IC₅₀ of 0.8–3 µmol/L. Conversely, 5-azacytidine was not cytotoxic to peripheral blood mononuclear cells or patient-derived bone marrow stromal cells (BMSC) at these doses. Importantly, 5-azacytidine overcame the survival and growth advantages conferred by exogenous interleukin-6 (IL-6), insulin-like growth factor-I (IGF-I), or by adherence of MM cells to BMSCs. 5-Azacytidine treatment induced DNA double-strand break (DSB) responses, as evidenced by H2AX, Chk2, and p53 phosphorylations, and apoptosis of MM cells. 5-Azacytidine–induced apoptosis was both caspase dependent and independent, with caspase 8 and caspase 9 cleavage; Mcl-1 cleavage; Bax, Puma, and Noxa up-regulation; as well as release of AIF and EndoG from the mitochondria. Finally, we show that 5-azacytidine–induced DNA DSB responses were mediated predominantly by ATR, and that doxorubicin, as well as bortezomib, synergistically enhanced 5-azacytidine–induced MM cell death. Taken together, these data provide the preclinical rationale for the clinical evaluation of 5-azacytidine, alone and in combination with doxorubicin and bortezomib, to improve patient outcome in MM. [Mol Cancer Ther 2007;6(6):1718–27]

Grant support: Pharmion Corporation; Yearley Family Research Fellowship (T. Kiziltepe); NIH grants RO-1 A50947, PO-1 CA78373, Specialized Programs of Research Excellence P50 CA100707, a Doris Duke Distinguished Clinical Research Scientist Award (K.C. Anderson); Multiple Myeloma Research Foundation Senior Research Award (D. Chauhan); The Myeloma Research Fund (T. Kiziltepe); and The Lebow Family Fund.

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.

Note: Author's contributions: T. Kiziltepe designed, did, and analyzed research and wrote the manuscript. T. Hideshima, L. Catley, and N. Raje participated in the design and interpretation of data. H. Ikeda, Y. Okawa, H. Yasui and S. Vallet, K. Ishitsuka, N. Shiraishi, S. Pozzi, and E.M. Ocio contributed to data generation. D. Chauhan participated in the design of the study. K.C. Anderson participated in the design, coordination, and performance of the study, assisted in writing the manuscript, and funded the study.

¹ Supplementary material for this article are available at Molecular Cancer Therapeutics Online (http://mct.aacrjournals.org/).

Received 1/ 4/07; revised 4/ 4/07; accepted 4/27/07.

This article has been cited by other articles:

				T. Khong, J. Sharkey, and A. Spencer The effect of azacitidine on interleukin-6 signaling and nuclear factor-{kappa}B activation and its in vitro and in vivo activity against multiple myeloma Haematologica, June 1, 2008; 93(6): 860 - 869. [Abstract] [Full Text] [PDF]