Roles of p15Ink4b and p16Ink4a in myeloid differentiation and RUNX1-ETO-associated acute myeloid leukemia.
Inactivation of p15(Ink4b) expression by promoter hypermethylation occurs in up to 80% of acute myeloid leukemia (AML) cases and is particularly common in the FAB-M2 subtype of AML, which is characterized by the presence of the RUNX1-ETO translocation in 40% of cases. To establish whether the loss of p15(Ink4b) contributes to AML progression in association with RUNX1-ETO, we have expressed the RUNX1-ETO fusion protein from a retroviral vector in hematopoietic progenitor cells isolated from wild-type, p15(Ink4b) or p16(Ink4a) knockout bone marrow. Analysis of lethally irradiated recipient mice reconstituted with RUNX1-ETO-expressing cells showed that neither p15(Ink4b) or p16(Ink4a) loss significantly accelerated disease progression over the time period of one year post-transplantation. Loss of p15(Ink4b) alone resulted in increased myeloid progenitor cell frequencies in bone marrow by 10-month post-transplant and a 19-fold increase in the frequency of Lin(-)c-Kit(+)Sca-1(+) (LKS) cells that was not associated with expansion of long-term reconstituting HSC. These results strongly suggest that p15(Ink4b) loss must be accompanied by additional oncogenic changes for RUNX1-ETO-associated AML to develop.
Ko
Rose M
RM
Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294, United States.
Kim
Hyung-Gyoon
HG
Wolff
Linda
L
Klug
Christopher A
CA
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology*; D050676:Core Binding Factor Alpha 2 Subunit / Q000502:physiology*; D050762:Cyclin-Dependent Kinase Inhibitor p15 / Q000235:genetics / Q000502:physiology*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000502:physiology*; D017931:DNA Primers; D015470:Leukemia, Myeloid, Acute / Q000473:pathology / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL
D050676:Core Binding Factor Alpha 2 Subunit; D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16; D017931:DNA Primers; C493726:Runx1 protein, mouse