Altered gene expression in busulfan-resistant human myeloid leukemia.

Abstract

Busulfan (Bu) resistance is a major obstacle to hematopoietic stem cell transplantation (HSCT) of patients with chronic or acute myelogenous leukemia (CML or AML). We used gene expression analysis to identify cellular factors underlying Bu resistance. Two Bu-resistant leukemia cell lines were established, characterized and analyzed for differentially expressed genes. The CML B5/Bu250(6) cells are 4.5-fold more resistant to Bu than their parental B5 cells. The AML KBM3/Bu250(6) cells are 4.0-fold more Bu-resistant than KBM3 parental cells. Both resistant sublines evade Bu-mediated G2-arrest and apoptosis with altered regulations of CHK2 and CDC2 proteins, constitutively up-regulated anti-apoptotic genes (BCL-X(L), BCL2, BCL2L10, BAG3 and IAP2/BIRC3) and down-regulated pro-apoptotic genes (BIK, BNIP3, and LTBR). Bu-induced apoptosis is partly mediated by activation of caspases; use of the inhibitor Z-VAD-FMK completely abrogated PARP1 cleavage and reduced apoptosis by approximately 50%. Furthermore, Bu resistance in these cells may be attributed in part to up-regulation of HSP90 protein and activation of STAT3. The inhibition of HSP90 with geldanamycin attenuated phosphorylated STAT3 and made B5/Bu250(6) and KBM3/Bu250(6) more Bu-sensitive. The analysis of cells derived from patients classified as either clinically resistant or sensitive to high-dose Bu-based chemotherapy indicated alterations in gene expression that were analogous to those observed in the in vitro model cell lines, confirming the potential clinical relevance of this model for Bu resistance.

• Authors: Benigno C Valdez, David Murray, Latha Ramdas, Marcos de Lima, Roy Jones, Steven Kornblau, Daniel Betancourt, Yang Li, Richard E Champlin, Borje S Andersson
• Journal: Leukemia research (Leuk Res) Vol. 32 Issue 11 Pg. 1684-97 (Nov 2008) ISSN: 0145-2126 [Print] England
• PMID: 18339423 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents, Alkylating
• Biomarkers, Tumor
• HSP90 Heat-Shock Proteins
• STAT3 Transcription Factor
• STAT3 protein, human
• PARP1 protein, human
• Poly (ADP-Ribose) Polymerase-1
• Poly(ADP-ribose) Polymerases
• Caspases
• Busulfan

Topics

• Antineoplastic Agents, Alkylating (pharmacology)
• Apoptosis (drug effects)
• Biomarkers, Tumor (genetics, metabolism)
• Busulfan (pharmacology)
• Caspases (metabolism)
• Drug Resistance, Neoplasm (genetics)
• Enzyme Activation (drug effects)
• G2 Phase (drug effects)
• Gene Expression Profiling
• Gene Expression Regulation, Leukemic (drug effects)
• HSP90 Heat-Shock Proteins (genetics, metabolism)
• Humans
• Leukemia, Myeloid (genetics, pathology)
• Poly (ADP-Ribose) Polymerase-1
• Poly(ADP-ribose) Polymerases (genetics, metabolism)
• STAT3 Transcription Factor (genetics, metabolism)
• Tumor Cells, Cultured