Frequent epigenetic inactivation of the SLIT2 gene in chronic and acute lymphocytic leukemia.
Recently a mouse model of T/natural killer acute lymphoblastic leukemia was used to assess global promoter methylation across the mouse genome using the restriction landmark genomic scanning technique. One of the methylated mouse genes identified in this way was Slit2. There are three mammalian SLIT genes (SLIT1, SLIT2, SLIT3), that belong to a highly conserved family of axon guidance molecules. We have previously demonstrated that SLIT2 is frequently inactivated in lung, breast, colorectal and glioma tumors by hypermethylation of a CpG island in its promoter region, whilst inactivating somatic mutations are rare. Furthermore, we demonstrated that SLIT2 acts as a tumor suppressor gene in breast and colorectal cancer cells. In this report we determined the methylation status of the SLIT2 gene in leukemias (CLL and ALL). SLIT2 was methylated in all ten leukemia cell lines analyzed (eight completely and two partially methylated). SLIT2 expression was restored after treating ALL lines with 5-aza-2dC. In primary ALL and CLL samples, SLIT2 was also frequently methylated, 58% (30/52) B-ALL; 83% (10/12) T-ALL and in 80% (24/30) CLL. Whilst DNA from peripheral blood and bone marrow from healthy control samples showed no SLIT2 methylation. Methylation results in leukemia cell lines and ALL and CLL primary samples were confirmed by direct sequencing of bisulfite modified DNA. Our results demonstrate that methylation of the SLIT2 5' CpG island is conserved between mice and humans, and therefore is likely to be of functional importance.
Dunwell
Thomas L
TL
Section of Medical and Molecular Genetics, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
Dickinson
Rachel E
RE
Stankovic
Tatjana
T
Dallol
Ashraf
A
Weston
Victoria
V
Austen
Belinda
B
Catchpoole
Daniel
D
Maher
Eamonn R
ER
Latif
Farida
F
D001853:Bone Marrow / Q000378:metabolism; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000378:metabolism; D000098552:Slit Homolog 2 Protein
D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D000098552:Slit Homolog 2 Protein