SNP rs12982687 affects binding capacity of lncRNA UCA1 with miR-873-5p: involvement in smoking-triggered colorectal cancer progression

Abstract

Background: This investigation was arranged to elucidate whether single nucleotide polymorphisms (SNPs) of lncRNA UCA1 was implicated in elevating colorectal cancer (CRC) risk by interacting with environmental exposures.

Methods: LncRNASNP database was firstly adopted to predict SNPs that possibly affected binding of UCA1 with miRNAs and then the interactive effect of SNPs and environmental exposure on CRC risk was evaluated by recurring to type 2 gene-environment interactions (GEI) model. Besides, MTT assay, colony formation assay, transwell assay and wound healing assay were performed to assess the activity of CRC cell lines which carried distinct genotypes of specific SNPs. The impact of nicotine on activity of CRC cells was also appraised.

Results: SNP rs12982687 of UCA1 intervened in the binding capacity of UCA1 with several miRNAs, especially miR-873-5p. MiRNAs regulated by UCA1, as predicted by mirPath software, shared genes that were enriched in HIF1 signaling pathway. Moreover, homozygote TT of rs12982687 reduced CRC risk among smokers, and CRC cells that carried rs12982687 (CC) displayed strong migration and invasion. By contrast, miR-873-5p mimic, which reduced UCA1 expression, delayed metastasis of CRC cells (all P < 0.05). Additionally, nicotine not merely elevated UCA1 and HIF-1α expressions in CRC cells, but also facilitated proliferation and metastasis of CRC cells (P < 0.05).

Conclusions: SNP rs12982687 was involved in smoking-triggered CRC progression, given its influence on UCA1's binding with miR-873-5p and HIF-1 signaling.

Keywords: CRC; Cell migration; Cell proliferation; Gene-environment interaction; Nicotine; Single nucleotide polymorphism; lncRNA UCA1; miR-873-5p.

Fig. 1

Association of single nucleotide polymorphisms (SNPs) in lncRNA UCA1 with survival of colorectal cancer (CRC) patients. a The secondary structure of UCA1 varied between allele C (left) and allele T (right) of rs12982687. The red block was indicative of changes in the secondary structure of UCA1. b The secondary structure of UCA1 differed between allele A (left) and allele G (right) of rs11085996. The red block was indicative of changes in the secondary structure of UCA1. c Four-year survival was compared among CRC patients who carried distinct genotypes of rs11085996 (up) and rs12982687 (down). d MiRNAs that possibly bound to UCA1 were quantified within CRC tissues and adjacent non-tumor tissues. The miRNAs were deemed as down-regulated when their -log10 (false discovery rate) was > 1.2 and log2 (fold change) was <− 0.5. e Correlations of UCA1 expression with miRNA levels were displayed by establishing correlation matrix. f Survival curves were depicted to assess the association of UCA1, miR-873-5p, miR-1207-5p and miR-584 expressions with CRC prognosis

Fig. 2

Single nucleotide polymorphism (SNP) rs12982687 (C > T) affected binding of UCA1 with miRNAs in colorectal cancer (CRC) cells. a The luciferase activity of CRC cells was compared between allele T + miR-873-5p/miR-1207-5p/miR-584 mimic group and allele C + miR-873-5p/miR-1207-5p/miR-584 mimic group. *: P < 0.05 when compared with allele T + miR-873-5p/miR-1207-5p/miR-584 mimic group. b UCA1 expression was determined when miR-873-5p mimic, miR-873-5p inhibitor or miR-NC was transfected into CRC cells, and miR-873-5p expression was measured among CRC cells of pcDNA3.1, pcDNA3.1-UCA1, si-UCA1 and NC groups. *: P < 0.05 when compared with NC group. c The genotype of rs12982687 (C > T) was determined within SW620 cell line and within SW480 cell line. d Expressional change of HIF-1α in SW620 and SW480 cell lines was determined in case of altered expression of UCA1 and miR-873-5p, and expressions of UCA1 and miR-873-5p were monitored when HIF-1α level was intentionally changed in CRC cells *: P < 0.05 when compared with NC group

Fig. 3

Single nucleotide polymorphism (SNP) rs12982687 (C > T) affected invasion, migration and epithelial-mesenchymal transition (EMT) of colorectal cancer (CRC) cells. a Invasive capability of SW620 and SW480 cell lines was assessed when miR-873-5p expression was up-regulated and down-regulated. *: P < 0.05 when compared with miR-NC group. b The migratory potency of SW620 and SW480 cell lines was compared among miR-NC, miR-873-5p mimic and miR-873-5p inhibitor groups. *: P < 0.05 when compared with miR-NC group. c Expressions of EMT-related proteins were detected within SW620 and SW480 cell lines of miR-NC, miR-873-5p mimic and miR-873-5p inhibitor groups. *: P < 0.05 when compared with miR-NC group

Fig. 4

Single nucleotide polymorphism rs12982687 (C > T) affected viability, proliferation and apoptosis of colorectal cancer (CRC) cells. a Viability of SW620 and SW480 cell lines was measured among miR-NC, miR-873-5p mimic and miR-873-5p inhibitor groups. *: P < 0.05 when compared with miR-NC group. b Multiplication of SW620 and SW480 cell lines was contrasted among miR-NC, miR-873-5p mimic and miR-873-5p inhibitor groups. *: P < 0.05 when compared with miR-NC group. c The apoptotic rates of SW620 and SW480 cell lines were appraised among miR-NC, miR-873-5p mimic and miR-873-5p inhibitor groups. *: P < 0.05 when compared with miR-NC group

Fig. 5

Nicotine regulated viability, proliferation, migration and invasion of colorectal cancer (CRC) cells. a Viability of SW620 and SW480 cell lines was assessed under treatments of 0, 5, 10 and 50 μmol/L nicotine. *: P < 0.05 when compared with treatment of 0 μmol/L nicotine. b Proliferation of SW620 and SW480 cell lines was measured under treatments of 0, 5, 10 and 50 μmol/L nicotine. *: P < 0.05 when compared with treatment of 0 μmol/L nicotine. c Invasive ability of SW620 and SW480 cell lines was evaluated under treatments of 0, 5, 10 and 50 μmol/L nicotine. *: P < 0.05 when compared with treatment of 0 μmol/L nicotine. d Nicotine at different concentrations (i.e. 0, 5, 10 and 50 μmol/L) facilitated migratory potential of SW620 and SW480 cell lines. *: P < 0.05 when compared with treatment of 0 μmol/L nicotine

Fig. 6

Nicotine affected epithelial-mesenchymal transition (EMT) and apoptosis of colorectal cancer (CRC) cells. a Expressions of EMT-specific proteins were determined under treatments of 0, 5, 10 and 50 μmol/L nicotine. *: P < 0.05 when compared with treatment of 0 μmol/L nicotine. b Nicotine at different concentrations (i.e. 0, 5, 10 and 50 μmol/L) prohibited apoptosis of SW620 and SW480 cell lines. *: P < 0.05 when compared with treatment of 0 μmol/L nicotine. c UCA1 and miR-873-5p expressions were determined under the treatment of 10 μmol/L nicotine. *: P < 0.05 when compared with NC group