title: Co‑inhibition of miRNA‑21 and miRNA‑221 induces apoptosis by enhancing the p53‑mediated expression of pro‑apoptotic miRNAs in laryngeal squamous cell carcinoma.
abstract: Dysregulation of a numerous microRNAs (miRNAs) has been implicated in laryngeal squamous cell carcinoma (LSCC). Among those miRNAs, miR‑21 and miR‑221 are co‑overexpressed and commonly target the phosphatase and tensin homolog protein (PTEN) that is located in the PTEN‑Akt signaling pathway. The present study investigated whether co‑inhibition of miR‑21 and miR‑221 induced synergistic apoptosis of human LSCC cells. Methyl thiazolyl tetrazolium (MTT) and terminal deoxynucleotidyl‑transferase‑mediated deoxynucleotide triphosphate nick end labeling (TUNEL) assays were used to observe the potential effect of miR‑21 and miR‑221 on cell viability and apoptosis in cells co‑transfected with anti‑miRNA oligonucleotide (AMO)‑21 and AMO‑221. The protein expression levels of PTEN, Akt and p53 were determined by western blotting. The cellular abundance of 6 pro‑apoptotic miRNAs transcribed by p53 mediation, consisting of miR‑15a, miR‑16‑1, miR‑26a, miR‑34a, miR‑143 and miR‑203, was measured with using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). MTT results indicate that in vitro co‑transfection of AMO‑21 and AMO‑221 leads to a decline in cell viability, compared with the transfection of AMO alone. This result was verified by the detection of apoptosis using TUNEL assays. Co‑transfection of AMO‑21 and AMO‑221 resulted in a marked reduction in Akt phosphorylation and enhanced expression of PTEN and p53 were observed; consequently, leading to an amplification of the transcription of 6 pro‑apoptotic miRNAs. The present findings confirmed that co‑inhibition of miR‑21 and miR‑221 synergistically triggers cell apoptosis in vitro. The altered PTEN‑Akt signaling and p53‑mediated amplification of the transcription of pro‑apoptotic miRNAs may be involved in the observed synergistic effect. The present study provides novel insights into the mechanism underlying apoptosis‑associated miRNA‑miRNA mutual regulation in LSCC.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Kan
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Jianguang
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Minghua
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Qiuying
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Linli
authors.initials: L
authors.lastname: Tian
mesh_terms: D017209:Apoptosis; D002294:Carcinoma, Squamous Cell; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D006801:Humans; D007822:Laryngeal Neoplasms; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D035683:MicroRNAs; D051059:PTEN Phosphohydrolase; D051057:Proto-Oncogene Proteins c-akt; D012334:RNA, Neoplasm; D016159:Tumor Suppressor Protein p53; C524940:MIRN21 microRNA, human; C525709:MIR221, human; C495901:TP53 protein, human; C494929:PTEN protein, human