Abstract
Survivin is a novel member of the inhibitor of apoptosis protein (IAP) family. Here we report that the chemotherapeutic drug doxorubicin, a DNA-damaging agent, activates a p53-survivin signaling pathway inducing cell cycle arrest and apoptosis in childhood acute lymphoblastic leukemia (ALL). Treatment of wild-type (wt) p53 ALL cells (EU-3 cell line) with doxorubicin caused accumulation of p53, resulting in dramatic down-regulation of survivin, depletion of cells in G2/M, and apoptosis (increased sub-G1compartment). In contrast, doxorubicin treatment of mutant (mut) p53 cells (EU-6/ALL line) up-regulated survivin and induced G2/M arrest without inducing apoptosis. However, treating EU-6 with anti-survivin antisense resensitized these cells to doxorubicin, resulting in apoptosis. With a p53-null cell line (EU-4), although doxorubicin treatment arrested cells in G2/M, survivin expression was unchanged, and cells underwent only limited apoptosis. However, re-expression of wt-p53 in EU-4 cells could restore the doxorubicin-p53-survivin pathway, resulting in significantly decreased survivin expression and increased apoptosis in these cells after doxorubicin treatment. Following cotransfection of p53-null EU-4 cells with survivin promoter-luciferase constructs and either wt-p53 or different mut-p53 expression vectors, wt-p53 inhibited survivin promoter activity; p53-mediated inhibition could be abrogated by overexpression of murine double minute2 (MDM2) protein. Together, these studies define a novel p53-survivin signaling pathway activated by DNA damage that results in down-regulation of survivin, cell cycle arrest, and apoptosis. Furthermore, our data indicate that loss of wt-p53 function in tumor cells may contribute to up-regulation of survivin and resistance to DNA-damaging agents.
Footnotes
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Supported by grants from the National Cancer Institute-National Institutes of Health (R01 CA82323), CURE Childhood Cancer, Inc., Children's Healthcare of Atlanta, and a National Cancer Institute Cancer Center Support Grant (CA 16056).
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DOI: 10.1124/jpet.102.037192
- Abbreviations:
- MDM2
- murine double minute2
- IAP
- inhibitor of apoptosis protein
- CDE
- cell cycle-dependent element
- CHR
- cell cycle genes homology region
- ALL
- acute lymphoblastic leukemia
- wt
- wild type
- mut
- mutant
- FBS
- fetal bovine serum
- SSC
- standard saline citrate
- PARP
- poly(ADP-ribose) polymerase
- BrdUrd
- bromodeoxyuridine
- PBS
- phosphate-buffered saline
- PI
- propidium iodide
- G418
- geneticin
- bp
- base pair
- GM-CSF
- granulocyte-macrophage colony-stimulating factor
- Received April 8, 2002.
- Accepted June 3, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
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