title: Functional analysis of microRNAs in human hepatocellular cancer stem cells.
abstract: MicroRNAs are endogenous small non-coding RNAs that regulate gene expression and cancer development. A rare population of hepatocellular cancer stem cells (HSCs) holds the extensive proliferative and self-renewal potential necessary to form a liver tumour. We postulated that specific transcriptional factors might regulate the expression of microRNAs and subsequently modulate the expression of gene products involved in phenotypic characteristics of HSCs. We evaluated the expression of microRNA in human HSCs by microarray profiling, and defined the target genes and functional effects of two groups of microRNA regulated by IL-6 and transcriptional factor Twist. A subset of highly chemoresistant and invasive HSCs was screened with aberrant expressions of cytokine IL-6 and Twist. We demonstrated that conserved let-7 and miR-181 family members were up-regulated in HSCs by global microarray-based microRNA profiling followed by validation with real-time polymerase chain reaction. Importantly, inhibition of let-7 increases the chemosensitivity of HSCs to sorafenib and doxorubicin whereas silencing of miR-181 led to a reduction in HSCs motility and invasion. Knocking down IL-6 and Twist in HSCs significantly reduced let-7 and miR-181 expression and subsequently inhibited chemoresistance and cell invasion. We showed that let-7 directly targets SOCS-1 and caspase-3, whereas miR-181 directly targets RASSF1A, TIMP3 as well as nemo-like kinase (NLK). In conclusion, alterations of IL-6- and Twist-regulated microRNA expression in HSCs play a part in tumour spreading and responsiveness to chemotherapy. Our results define a novel regulatory mechanism of let-7/miR-181s suggesting that let-7 and miR-181 may be molecular targets for eradication of hepatocellular malignancies.
authors.affiliation: Department of Medicine and Scott & White Digestive Disease Research Center, Texas A&M Health Science Center College of Medicine and Scott & White Hospital, Temple, TX 76504, USA.
authors.forename: Fanyin
authors.initials: F
authors.lastname: Meng
authors.forename: Shannon S
authors.initials: SS
authors.lastname: Glaser
authors.forename: Heather
authors.initials: H
authors.lastname: Francis
authors.forename: Sharon
authors.initials: S
authors.lastname: DeMorrow
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Han
authors.forename: Jenna D
authors.initials: JD
authors.lastname: Passarini
authors.forename: Allison
authors.initials: A
authors.lastname: Stokes
authors.forename: John P
authors.initials: JP
authors.lastname: Cleary
authors.forename: Xiuping
authors.initials: X
authors.lastname: Liu
authors.forename: Julie
authors.initials: J
authors.lastname: Venter
authors.forename: Preetham
authors.initials: P
authors.lastname: Kumar
authors.forename: Sally
authors.initials: S
authors.lastname: Priester
authors.forename: Levi
authors.initials: L
authors.lastname: Hubble
authors.forename: Dustin
authors.initials: D
authors.lastname: Staloch
authors.forename: Jay
authors.initials: J
authors.lastname: Sharma
authors.forename: Chang-Gong
authors.initials: CG
authors.lastname: Liu
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Alpini
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001557:Benzenesulfonates / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016000:Cluster Analysis; D019008:Drug Resistance, Neoplasm; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D016513:Mice, SCID; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D009536:Niacinamide / Q000031:analogs & derivatives; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010671:Phenylurea Compounds; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000502:physiology; D011725:Pyridines / Q000494:pharmacology; D000077157:Sorafenib; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D035683:MicroRNAs; D009687:Nuclear Proteins; D010671:Phenylurea Compounds; D011725:Pyridines; C103173:TWIST1 protein, human; D051879:Twist-Related Protein 1; D009536:Niacinamide; D000077157:Sorafenib