| |
|
|
|
|
|
|
|||
|
Blood, 23 April 2009, Vol. 113, No. 17, pp. 4052-4062. Prepublished online as a Blood First Edition Paper on January 14, 2009; DOI 10.1182/blood-2008-05-156422.
MYELOID NEOPLASIA Enhanced activation of STAT pathways and overexpression of survivin confer resistance to FLT3 inhibitors and could be therapeutic targets in AML1 Department of Medicine and 2 Oncology Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; 3 Department of Hematology-Oncology, National University Hospital, Singapore; 4 Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; 5 Institute of Biotechnology and Nanotechnology, A*STAR, Singapore; 6 Abbott Laboratories, Chicago, IL; and 7 Division of Hematology and Oncology School of Medicine, Loma Linda University, CA To further investigate potential mechanisms of resistance to FLT3 inhibitors, we developed a resistant cell line by long-term culture of MV4-11 cells with ABT-869, designated as MV4-11-R. Gene profiling reveals up-regulation of FLT3LG (FLT3 ligand) and BIRC5 (survivin), but down-regulation of SOCS1, SOCS2, and SOCS3 in MV4-11-R cells. Hypermethylation of these SOCS genes leads to their transcriptional silencing. Survivin is directly regulated by STAT3. Stimulation of the parental MV4-11 cells with FLT3 ligand increases the expression of survivin and phosphorylated protein STAT1, STAT3, STAT5. Targeting survivin by short-hairpin RNA (shRNA) in MV4-11-R cells induces apoptosis and augments ABT-869–mediated cytotoxicity. Overexpression of survivin protects MV4-11 from apoptosis. Subtoxic dose of indirubin derivative (IDR) E804 resensitizes MV4-11-R to ABT-869 treatment by inhibiting STAT signaling activity and abolishing survivin expression. Combining IDR E804 with ABT-869 shows potent in vivo efficacy in the MV4-11-R xenograft model. Taken together, these results demonstrate that enhanced activation of STAT pathways and overexpression of survivin are important mechanisms of resistance to ABT-869, suggesting that the STAT pathways and survivin could be potential targets for reducing resistance developed in patients receiving FLT3 inhibitors.
Related Article in Blood Online:
This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Copyright © 2009 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||