Signal Transducer and Activator of Transcription-3 Induces MicroRNA-155 Expression in Chronic Lymphocytic Leukemia

Ping Li, Srdana Grgurevic, Zhiming Liu, David Harris, Uri Rozovski, George A. Calin, Michael J. Keating, Zeev Estrov

Research output: Contribution to journalArticlepeer-review

Abstract

MicroRNA (miR) abnormalities play a key role in the pathogenesis of chronic lymphocytic leukemia (CLL). High levels of miR-155 have been detected in human neoplasms, and overexpression of miR-155 has been found to induce lymphoma in mice. High levels of miR-155 were detected in CLL cells and STAT3, which is known to induce miR-21 and miR-181b-1 expression, is constitutively activated in CLL. Given these findings, we hypothesized that STAT3 induces miR-155. Sequence analysis revealed that the miR-155 promoter harbors two putative STAT3 binding sites. Therefore, truncated miR-155 promoter constructs and STAT3 small interfering RNA (siRNA) were co-transfected into MM1 cells. Of the two putative binding sites, STAT3-siRNA reduced the luciferase activity of the construct containing the 700-709 bp STAT3 binding site, suggesting that this site is involved in STAT3-induced transcription. Electrophoretic mobility shift assay confirmed that STAT3 bound to the miR-155 promoter in CLL cells, and chromatin immunoprecipitation and luciferase assay confirmed that STAT3 bound to the 700-709 bp but not the 615-624 bp putative STAT3 binding site in CLL cells. Finally, STAT3-small hairpin RNA downregulated miR-155 gene expression, suggesting that constitutively activated STAT3 binds to the miR-155 gene promoter. Together, these results suggest that STAT3 activates miR-155 in CLL cells.

Original languageEnglish
Article numbere64678
JournalPLoS ONE
Volume8
Issue number6
DOIs
StatePublished - 4 Jun 2013
Externally publishedYes

Fingerprint

Dive into the research topics of 'Signal Transducer and Activator of Transcription-3 Induces MicroRNA-155 Expression in Chronic Lymphocytic Leukemia'. Together they form a unique fingerprint.

Cite this