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MicroRNAs (miRNAs) are known to play a regulatory role in various cancers including laryngocarcinoma. MiR‐29a‐3p is a potential tumor‐suppressive miRNA, but its function in laryngocarcinoma is unknown. The purpose of this study was to investigate the roles of miR‐29a‐3p in laryngocarcinoma. Prominin1 (PROM1) was predicted as a target gene of miR‐29a‐3p and this was verified using a luciferase reporter assay. Transfection of miR‐29a‐3p into two laryngocarcinoma cell lines indicated that miR‐29a‐3p could decrease cell proliferation and enhance the chemotherapy response by targeting PROM1. PROM1 expression was up‐regulated in the laryngocarcinoma cells when miR‐29a‐3p was down‐regulated. We found miR‐29a‐3p expression levels were lower in laryngocarcinoma tissues than in control tissues. We also found that miR‐29a‐3p expression was negatively correlated with PROM1 expression in laryngocarcinoma tissues. The study demonstrates that miR‐29a‐3p suppresses cell proliferation in laryngocarcinoma by targeting PROM1.

Laryngeal squamous cell carcinoma (LSCC) is a highly aggressive malignant cancer and accounts for 1% to 2% of all malignancies diagnosed worldwide. Runt-related transcription factor 3 (RUNX3), an important tumor suppressor, is known to related to lymph node metastasis and the development of LSCC. However, the biological roles and potential mechanisms RUNX3 expression was not well understood. In this study, we reported that the RUNX3 was significantly downregulated and highly methylated in LSCC compared with their matched normal. The enforced expression of RUNX3 inhibited LSCC cell migration, invasion, and proliferation, whereas the inhibition of RUNX3 did the opposite. We identified that RUNX3 was regulated by miR-148a-3p and found that the expression level of miR-148-3p was significantly decreased and positively related with the expression of RUNX3 in LSCC. We also identified that DNA methyltransferase enzyme DNA (cytosine-5-)-methyltransferase 1 (DNMT1) was targeted by miR-148a-3p in LSCC. The knockdown of DNMT1 promoted the expression of RUNX3 and inhibited migration, invasion, and proliferation in LSCC cells. In summary, our study demonstrated that miR-148a-3p may regulate RUNX3 expression through the modulation of DNMT1-dependent DNA methylation in LSCC, providing a novel target and a potential therapeutic pathway against LSCC. LSCC is a highly aggressive malignant cancer and accounts for 1% to 2% of all malignancies diagnosed worldwide. In this study, we reported that RUNX3, an important tumor suppressor, was significantly downregulated and highly methylated in LSCC compared with their matched normal. The overexpression of RUNX3 inhibited LSCC cell migration, invasion, and proliferation, whereas the inhibition of RUNX3 did the opposite. Moreover, RUNX3 was regulated by miR-148a-3p, which targeted DNA methyltransferase enzyme DNMT1 in LSCC cells. Therefore, miR-148a-3p may regulate RUNX3 expression through the modulation of DNMT1-dependent DNA methylation in LSCC, providing a novel target and a potential therapeutic pathway against LSCC.

Many studies have investigated the association between CYP1A1 rs1048943 and rs4646903 polymorphisms and laryngeal cancer risk, but their results have been inconsistent. The PubMed and CNKI were searched for case–control studies published up to 01 July 2015. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. In this meta‐analysis, we assessed 10 published studies involving comprising 748 laryngeal cancer cases and 1558 controls of the association between CYP1A1 rs1048943 and rs4646903 polymorphisms and laryngeal cancer risk. For CYP1A1 rs1048943 of the homozygote G/G and G allele carriers (A/G + G/G) versus A/A, the pooled ORs were 1.77 (95% CI = 1.28–2.81, P = 0.007 for heterogeneity) and 1.86 (95% CI = 1.45–2.40, P = 0.000 for heterogeneity). For CYP1A1 rs4646903 of the homozygote G/G and G allele carriers (A/G + G/G) versus A/A, the pooled ORs were 1.53 (95% CI = 1.31–2.21, P = 0.012 for heterogeneity) and 1.33(95% CI = 1.04–1.71, P = 0.029 for heterogeneity). In the stratified analysis by ethnicity, the significantly risks were found among Asians for both the G allele carriers and homozygote G/G. However, no significant associations were found in Caucasian population all genetic models. These results from the meta‐analysis suggest that CYP1A1 rs1048943 and rs4646903 polymorphisms contribute to risk of laryngeal cancer among Asian populations.

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