MicroRNAs, stem cells and cancer stem cells

Table 1 miRNA mediated regulation in the maintenance and function of stem cells

miRNA	Functions in stem cells	Mechanism(s)	Ref.
Pluripotent miRNAs
miR-290 cluster, miR-370, miR-302	Promotes self-renewal	Regulate embryonic stem cell cycle	[32]
miR-141, miR-200, miR-429	Maintenance of self-renewal in the absence of leukemia inhibitory factor	Regulated by cMyc proteins	[66]
miR-9	Proliferation and promote NSC migration	Target Stmn1, which increases microtubule instability	[67]
	Neurite outgrowth	Inhibit Cdc42 expression and altering the localization of Rac1
miR-184	NSC proliferation	Represses the expression of Numb-like 1	[68]
miR-137	Promotes NSC proliferation but inhibits neuronal maturation, dendritic morphogenesis, and spine development	Target Mind bomb 1, an ubiquitin ligase	[69]
Pro-differentiation miRNAs
miR-134, miR-145, miR-296, miR-470	Initiate differentiation	Suppress pluripotent markers including Nanog, Oct4, Sox, Klf4	[33]
Let-7	Stabilize differentiation	Target transcripts that are regulated by the pluripotency transcription factors Oct4, Sox2, Nanog and Tcf3	[34]
		Promote somatic cell cycle by targeting both directly and indirectly the multiple activators of the G1-S transition including cdc25a, cdk6, cyclinD1 and cyclinD2	[35-37]
miR-124	NSC differentiation	Suppress Sox9 expression in adult NSCs and exhibit mutual inhibition mechanism of Ephrin-B1	[70]

Let-7: Lethal-7; NSC: Neuronal stem cell; Sox: Sex-determining region Y-box containing gene.