Noncoding RNAs in gastric cancer: Research progress and prospects

Table 1 Major classification of human genomic noncoding RNAs

RNA type	Symbol	Length (nt)	Function
Housekeeping ncRNAs
Transfer RNAs	tRNA	73-94	Connect amino acids with mRNA
Ribosomal RNAs	rRNA	121-5070	Component of ribosomes
Small nuclear RNAs	snRNA	Approximately 150	Assemble with proteins into spliceosomes to remove introns during mRNA processing
Small nucleolar RNAs	snoRNA	70-200	Guide modifications of other ncRNAs, alternative splicing; or function as miRNA
Telomerase RNAs	TERC	451	Provide template for de novo synthesis of telomeric DNA
Ribonuclease P	RPPH1	341	RNA component of ribonuclease P
Regulatory ncRNAs
Small interfering RNAs	siRNA	21-22	Silencing genes in a sequence-specific manner
MicroRNAs	miRNA	20-23	Regulating genes expression
Piwi-interacting RNA	piRNA	25-33	Silence transposons during spermatogenesis
Promoter-associated short RNAs	paRNA	< 200	Regulating gene expression by gene promoter
Long non-coding RNAs	lncRNA	> 200	Various

ncRNAs: Noncoding RNAs; piRNAs: PIWI-interacting RNAs; lncRNAs: Long ncRNAs.

Table 2 Related advances of noncoding RNAs in gastric cancer of this review

Type of ncRNAs	Expression	Putative roles	Pathway	Targets	Ref.
miRNAs
miR-29c	Downregulated	Early event in gastric carcinogenesis	Unknown	ITGB1	[18]
miR-448, miR-15a, miR-485-5p	Downregulated	Suppress proliferation, invasion or migration	Unknown		[19-21]
miR-1290, miR-543	Upregulated	Promote proliferation and metastasis	Unknown		[22,23]
miR-508-3p	Downregulated	Tumor suppressor effect	NF-κB signaling	NFKB1	[24]
miR-544a	Upregulated	Regulate EMT markers	Wnt signaling	CDH1, AXIN2	[25]
miR-375	Downregulated	Increase sensitivity to DPP treatment	Unknown	ERBB2, p-Akt	[26]
miR-143	Downregulated	Inhibit autophagy	Unknown	GABARAPL1	[27]
miR-27b	Downregulated	Inhibit HP-related proliferation	Wnt signaling	Unknown	[29]
lncRNAs
TUSC7	Downregulated	p53-dependent tumor suppressive role	Unknown	miR-23b	[43]
LSINCT5	Upregulated	Correlated with clinical parameters	Unknown	Unknown	[44]
H19	Upregulated	Biomarker, promote proliferation		miR-675	[46,49]
HOTAIR	Upregulated	Biomarker, inhibit apoptosis, promote invasion and metastasis			[59,60]
MALAT1	Upregulated	Promote migration and invasion	Unknown	EZH2	[63]
Linc00152	Upregulated	Promote cell proliferation, migration and invasion, cell cycle, and tumor growth	PI3K/Akt	EGFR	[64,65]
linc-POU3F3	Upregulated	Promote distribution of Treg cells	TGF-β	Unknown	[66]
MIR31HG	Downregulated	Inhibit proliferation	Unknown	E2F1/p21	[68]
piRNAs
piR-823	Downregulated	Tumor suppressive role			[75]
piR-651	Upregulated	Promote cell growth			[76]
circRNAs
Hsa_circ_002059	Downregulated	Biomarker			[83]
circ-Foxo3	Upregulated	Cell cycle, promote proliferation		p21/CDK2	[84]
circ-ITCH	Downregulated	miRNA sponge	Wnt/β-catenin		[85]

piRNAs: PIWI-interacting RNAs; lncRNAs: Long ncRNAs; circRNAs: Circular RNAs.