Abstract
Thirty percent of acute myeloid leukemia cases express a Core Binding Factor (CBF) oncoprotein or harbor point mutations in one or both AML1 (RUNX1) genes. Each of these alterations reduces endogenous CBF activities. CBFβ-SMMHC is expressed from the inv(16) chromosome in 8% of AML cases and inhibits endogenous CBF DNA-binding. Inhibition of CBF reduces Retinoblastoma protein phosphorylation and slows the G1 to S cell cycle transition. c-Myc, a protein which stimulates S phase entry, is over-expressed in one-third of AMLs. We have developed Ba/F3 cell lines in which zinc regulates CBFβ-SMMHC expression and 4-hydroxytamoxifen activates c-Myc-ER. In these lines, c-Myc-ER overcomes inhibition of cell cycle progression mediated by CBFβ-SMMHC. CBFβ-SMMHC does not affect endogenous c-Myc RNA levels, indicating that CBF does not regulate the c-Myc gene. Conversely, c-Myc-ER does not alter CBF DNA-binding activity. Thus, c-Myc-ER acts downstream of CBFβ-SMMHC to stimulate cell cycle progression. In a subset of CBF leukemias, elevated expression of c-Myc is expected to facilitate the proliferation of the leukemic blasts and thereby potentiate the ability of CBF oncoproteins to block differentiation.
Original language | English (US) |
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Pages (from-to) | 492-496 |
Number of pages | 5 |
Journal | Cancer Biology and Therapy |
Volume | 1 |
Issue number | 5 |
DOIs | |
State | Published - Sep 2002 |
Keywords
- AML1
- CBF
- CBFβ-SMMHC
- RUNX1
- c-Myc
ASJC Scopus subject areas
- Molecular Medicine
- Oncology
- Pharmacology
- Cancer Research