TY - JOUR
T1 - Oncogenic tyrosine kinase NPM-ALK induces expression of the growth-promoting receptor ICOS
AU - Zhang, Qian
AU - Wang, Hong Yi
AU - Kantekure, Kanchan
AU - Paterson, Jennifer C.
AU - Liu, Xiaobin
AU - Schaffer, Andras
AU - Paulos, Chrystal
AU - Milone, Michael C.
AU - Odum, Niels
AU - Turner, Suzanne
AU - Marafioti, Teresa
AU - Wasik, Mariusz A.
PY - 2011/9/15
Y1 - 2011/9/15
N2 - Here we report that T-cell lymphoma cells carrying the NPM-ALK fusion protein (ALK+ TCL) frequently express the cell-stimulatory receptor ICOS. ICOS expression in ALK+ TCL is moderate and strictly dependent on the expression and enzymatic activity of NPM-ALK. NPM-ALK induces ICOS expression via STAT3, which triggers the transcriptional activity of the ICOS gene promoter. In addition, STAT3 suppresses the expression of miR-219 that, in turn, selectively inhibits ICOS expression. ALK+ TCL cell lines display extensive DNA methylation of the CpG island located within intron 1, the putative enhancer region, of the ICOS gene, whereas cutaneous T-cell lymphoma cell lines, which strongly express ICOS, show no methylation of the island. Treatment of the ALK+ TCL cell lines with DNA methyltransferase inhibitor reversed the CpG island methylation and augmented the expression of ICOS mRNA and protein. Stimulation of the ICOS receptor with anti-ICOS antibody or ICOS ligand-expressing B cells markedly enhanced proliferation of the ALK+ TCL cells. These results demonstrate that NPM-ALK, acting through STAT3 as the gene transcriptional activator, induces the expression of ICOS, a cell growth promoting receptor. These data also show that the DNA methylation status of the intronic CpG island affects transcriptional activity of the ICOS gene and, consequently, modulates the concentration of the expressed ICOS protein.
AB - Here we report that T-cell lymphoma cells carrying the NPM-ALK fusion protein (ALK+ TCL) frequently express the cell-stimulatory receptor ICOS. ICOS expression in ALK+ TCL is moderate and strictly dependent on the expression and enzymatic activity of NPM-ALK. NPM-ALK induces ICOS expression via STAT3, which triggers the transcriptional activity of the ICOS gene promoter. In addition, STAT3 suppresses the expression of miR-219 that, in turn, selectively inhibits ICOS expression. ALK+ TCL cell lines display extensive DNA methylation of the CpG island located within intron 1, the putative enhancer region, of the ICOS gene, whereas cutaneous T-cell lymphoma cell lines, which strongly express ICOS, show no methylation of the island. Treatment of the ALK+ TCL cell lines with DNA methyltransferase inhibitor reversed the CpG island methylation and augmented the expression of ICOS mRNA and protein. Stimulation of the ICOS receptor with anti-ICOS antibody or ICOS ligand-expressing B cells markedly enhanced proliferation of the ALK+ TCL cells. These results demonstrate that NPM-ALK, acting through STAT3 as the gene transcriptional activator, induces the expression of ICOS, a cell growth promoting receptor. These data also show that the DNA methylation status of the intronic CpG island affects transcriptional activity of the ICOS gene and, consequently, modulates the concentration of the expressed ICOS protein.
UR - http://www.scopus.com/inward/record.url?scp=80052945186&partnerID=8YFLogxK
U2 - 10.1182/blood-2011-01-332916
DO - 10.1182/blood-2011-01-332916
M3 - Article
C2 - 21765024
AN - SCOPUS:80052945186
SN - 0006-4971
VL - 118
SP - 3062
EP - 3071
JO - Blood
JF - Blood
IS - 11
ER -