DDX6 post-transcriptionally down-regulates miR-143/145 expression through host gene NCR143/145 in cancer cells.
In various human malignancies, widespread dysregulation of microRNA (miRNA) expression is reported to occur and affects various cell growth programs. Recent studies suggest that the expression levels of miRNAs that act as tumor suppressors are frequently reduced in cancers because of chromosome deletions, epigenetical changes, aberrant transcription, and disturbances in miRNA processing. MiR-143 and -145 are well-recognized miRNAs that are highly expressed in several tissues, but down-regulated in most types of cancers. However, the mechanism of this down-regulation has not been investigated in detail. Here, we show that DEAD-box RNA helicase 6, DDX6 (p54/RCK), post-transcriptionally down-regulated miR-143/145 expression by prompting the degradation of its host gene product, NCR143/145 RNA. In human gastric cancer cell line MKN45, DDX6 protein was abundantly expressed and accumulated in processing bodies (P-bodies). DDX6 preferentially increased the instability of non-coding RNA, NCR143/145, which encompasses the miR-143/145 cluster, and down-regulated the expression of mature miR-143/145. In human monocytic cell line THP-1, lipopolysaccharide treatment promoted the assembly of P-bodies and down-regulated the expression of NCR143/145 and its miR-143/145 rapidly. In these cells, cycloheximide treatment led to a loss of P-bodies and to an increase in NCR143/145 RNA stability, thus resulting in up-regulation of miR-143/145 expression. These data demonstrate that DDX6 contributed to the control of NCR143/145 RNA stability in P-bodies and post-transcriptionally regulated miR-143/145 expression in cancer cells.
United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido, Gifu, Gifu 501-1193, Japan; Department of Embryology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya-cho, Kasugai, Aichi 480-0392, Japan. Electronic address: aiio@inst-hsc.jp.
Akio
A
Iio
Takeshi
T
Takagi
Kohei
K
Miki
Tomoki
T
Naoe
Atsuo
A
Nakayama
Yukihiro
Y
Akao
D015153:Blotting, Western; D002478:Cells, Cultured; D053487:DEAD-box RNA Helicases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000235:genetics; D009000:Monocytes / Q000166:cytology / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D062085:RNA, Long Noncoding / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism
C542359:MIRN143 microRNA, human; C541010:MIRN145 microRNA, human; D035683:MicroRNAs; D011518:Proto-Oncogene Proteins; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D008156:Luciferases; C094683:DDX6 protein, human; D053487:DEAD-box RNA Helicases
5′-3′ exoribonuclease 1; 7-methylguanosine; 7mG; ACTB; AGO1; AGO2; ARE; AU-rich elements; ActD; Argonaute 1; Argonaute 2; CHX; CRM1; DAPI; DCP1 decapping enzyme homolog A; DCP1A; DDX17; DDX5; DDX6; DEAD-box RNA helicase 17; DEAD-box RNA helicase 5; DEAD-box RNA helicase 6; EDC3; GAPDH; HIF1A; IFN-β; IPZ; IgG; LMB; LPS; Lipopolysaccharide; NC; NCR143/145; NMD; P-bodies; PVDF; RACE; RIPA; RISC; RN7SL1; RNA 7SL cytoplasmic 1; RNA-induced silencing complexes; RNU6B; TNF-α; U22 snoRNA host gene; U6 small nuclear B RNA; UHG; XRN1; actinomycin D; beta-actin; cycloheximide; diamidino-2-phenylindole; enhancer of mRNA decapping 3 homolog; glyceraldehyde-3-phosphate dehydrogenase; heterogeneous nuclear ribonucleoproteins; hnRNPs; hypoxia inducible factor 1 alpha subunit; immunoglobulin G; importazole; importin family nuclear export receptor; interferon-beta; leptomycin B; miR-143; miR-145; miRNA; microRNA; microRNA precursors; microRNA-143; microRNA-143/145 host non-coding RNA gene; microRNA-145; negative control; non-spliced NCR143/145; nonsense-mediated mRNA decay; nsNCR143/145; polyvinylidene fluoride; pre-miRNAs; pri-miRNAs; primary microRNA transcripts; processing bodies; r15-LOX; radioimmunoprecipitation assay; rapid amplification of cDNA ends; reticulocyte 15-lipoxigenase; tumor necrosis factor-alpha