miR-146a and miR-146b promote proliferation, migration and invasion of follicular thyroid carcinoma via inhibition of ST8SIA4

Mulligan

et al. 2017

Endocrine Connections

IntroductionMicroRNAs (miRNAs) are small noncoding RNA molecules that exert post-transcriptional effects on gene expression by binding with cis-regulatory regions in target messenger RNA (mRNA). Polymorphisms in genes encoding miRNAs or in miRNA–mRNA binding sites confer deleterious epigenetic effects on cancer risk. miR-146a has a role in inflammation and may have a role as a tumour suppressor. The polymorphism rs2910164 in the MIR146A gene encoding pre-miR-146a has been implicated in several inflammatory pathologies, including cancers of the breast and thyroid, although evidence for the associations has been conflicting in different populations. We aimed to further investigate the association of this variant with these two cancers in an Irish cohort.MethodsThe study group comprised patients with breast cancer (BC), patients with differentiated thyroid cancer (DTC) and unaffected controls. Germline DNA was extracted from blood or from saliva collected using the DNA Genotek Oragene 575 collection kit, using crystallisation precipitation, and genotyped using TaqMan-based PCR. Data were analysed using SPSS, v22.ResultsThe total study group included 1516 participants. This comprised 1386 Irish participants; 724 unaffected individuals (controls), 523 patients with breast cancer (BC), 136 patients with differentiated thyroid cancer (DTC) and three patients with dual primary breast and thyroid cancer. An additional cohort of 130 patients with DTC from the South of France was also genotyped for the variant. The variant was detected with a minor allele frequency (MAF) of 0.19 in controls, 0.22 in BC and 0.27 and 0.26 in DTC cases from Ireland and France, respectively. The variant was not significantly associated with BC (per allele odds ratio = 1.20 (0.98–1.46), P = 0.07), but was associated with DTC in Irish patients (per allele OR = 1.59 (1.18–2.14), P = 0.002).ConclusionThe rs2910164 variant in MIR146A is significantly associated with DTC, but is not significantly associated with BC in this cohort.

Section: Discussionmentioning

confidence: 99%

Investigating the association of rs2910164 with cancer predisposition in an Irish cohort

Mulligan

et al. 2017

Endocrine Connections

“…however, the expression of miR-146a is significantly higher in thyroid follicular carcinoma (32,33) and oral carcinoma (34), and the downregulation of miR-146a expression can inhibit the malignant biological behaviors of tumor cells. In addition, the negative feedback mechanism associated with miR-146a is not applicable to all tumor cells (35).…”

Section: Discussionmentioning

confidence: 96%

Effect and mechanism of miR‑146a on malignant biological behaviors of lung adenocarcinoma cell line

et al. 2020

The aim of the present study was to assess the expression of microRNA-146a (miR-146a) in human lung adenocarcinoma cells, its effect on cellular behaviors, and the underlying molecular mechanisms. Reverse transcription-quantitative PCR (RT-qPCR) was used to measure miR-146a expression in the human normal lung epithelial cell line, BEAS-2B, and human lung adenocarcinoma cell lines, A549, PC-9 and H1299, to determine whether miR-146a acts as an oncogene or anti-oncogene. miR-146a mimics were transfected into target cells to observe the proliferation, apoptosis, invasion and migration of human lung adenocarcinoma cells. The target genes of miR-146a were predicted using bioinformatics analysis, and binding sites were validated by dual-luciferase reporter assay. Target gene expression at the mRNA and protein levels was measured by RT-qPCR and western blot analysis, respectively. The expression levels of miR-146a in human lung adenocarcinoma cell lines were lower than its expression in BEAS-2B (P<0.01). A549 cell line is a EGFR wild-type lung adenocarcinoma cell line, which is also the most widely studied in NSCLC, and therefore this was chosen as the target cell line for further investigation. Overexpression of miR-146a in A549 cells can inhibit cell proliferation (P<0.05), promote apoptosis (P<0.05), and reduce the cells' migratory ability (P<0.01). Bioinformatics prediction indicated that interleukin-1 receptor-associated kinase 1 (IRAK1) and TNF receptor associated factor 6 (TRAF6) are the target genes of miR-146a. Dual-luciferase reporter assay showed that miR-146a could specifically bind to 3'-untranslated regions of IRAK1 and TRAF6. The protein and mRNA levels of IRAK1 and TRAF6 were significantly downregulated after miR-146a overexpression in A549 cells (P<0.01). The results of this study demonstrated that the expression of miR-146a in human lung adenocarcinoma cells was significantly lower than in normal lung epithelial cells, indicating that miR-146a acts as an anti-oncogene. miR-146a suppresses the proliferation and migration of human lung adenocarcinoma cells by downregulating the expression of IRAK1 and TRAF6.

Environmental Toxicology

“…The sialyltransferase ST8SIA4 is downregulated in invasive tumor cells and is also involved in EMT. 27,28 Therefore, we sought to determine whether ST8SIA4 is regulated by miR-146a. Bioinformatic analysis revealed a potential miR-146a binding site in the 3 0 UTR of ST8SIA4, and luciferase reporter assays confirmed that miR-146a can downregulate ST8SIA mRNA expression.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, alpha-2,8-sialyltransferase 4 (ST8SIA4) is expressed in various cancer and may be associated with OSCC, and is regulated by miR-146a. 14 In the present study, we investigated the effect of miR-146a on proliferation, invasion and EMT in OSCC cells. We also investigated the effects of miR-146a on the expression of ST8 alpha-N-acetylneuraminide Alpha-2,8-sialyltransferase 4 (ST8SIA), which is an important regulator of EMT.…”

Section: Introductionmentioning

confidence: 99%

miR‐146a promotes proliferation, invasion, and epithelial‐to‐mesenchymal transition in oral squamous carcinoma cells

Wang

et al. 2020

Epithelial‐to‐mesenchymal transition (EMT) is key to invasion and metastasis by oral squamous carcinoma (OSCC) cells. MicroRNAs (miRNAs) such as miRNA‐146a are known to be upregulated in OSCC. However, it is unclear whether they are involved in driving EMT. Here, we investigated the effect of miR‐146a overexpression on proliferation, migration, and EMT in OSCC cells. OSCC cells were transfected with a plasmid expressing miR‐146a precursor. Cell lines that stably overexpressed miRNA‐146a were assessed for proliferation, colony formation, and invasiveness in vitro. Expression of markers and regulators of EMT, cell motility, and invasion were measured by qRT‐PCR and western blot. Potential miRNA‐146a binding sites in the 3′UTR of ST8SIA4 were identified by bioinformatic analysis. To confirm that miRNA‐146a binds to and regulates ST8SIA4, we transfected OSCC cell lines with miRNA‐146a mimics and a luciferase reporter construct containing either the wild type or mutant 3′UTR of ST8SIA4. OSCC cell lines that overexpressed miR‐146a displayed higher proliferation, colony formation, invasion, and MMP‐2 activity than cells transfected with a control vector. Overexpression of miR‐146a also decreased expression of the epithelial cell marker E‐cadherin and increased expression of Twist1, a transcription factor that promotes EMT, as well as markers associated with mesenchymal cells (vimentin and N‐cadherin) and tumor invasion (p‐paxillin and p‐cortactin). Luciferase expression was lower in OSCC cells transfected with miRNA‐146a mimics or with luciferase constructs carrying the wild type, but not mutant, 3′UTR of ST8SIA4. Overexpression of miR‐146a promotes EMT phenotypes and may drive tumorigenesis and progression in OSCC, making it a useful target for future OSCC treatments.