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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. [ABSTRACT FROM AUTHOR]

CGA-N46 is a novel antifungal peptide derived from the N-terminus of human Chromogranin A, corresponding to the 31st to 76th amino acids. Further research on its activities and characteristics may be helpful for the application of CGA-N46 in medical or other situations. In the present study, the antifungal spectrum and physicochemical characteristics of CGA-N46 were investigated using an antifungal assay, its antiproliferative effects on cancer and normal cells were assessed using MTT assay and its combinatorial effect with other antibiotics was analyzed using checkerboard analysis. The results showed that CGA-N46 exhibited antifungal activity against the tested Candidas (C. glabrata, C. parapsilosis, C. krusei, C. tropicalis and C. albicans) at a concentration of <0.8 mM, but had no effect on the growth of filamentous fungi or other types of fungi (Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Fusarium moniliforme, Microsporum canis, Microsporum gypseum, Trichophyton rubrum and Trichophyton mentagrophytes), even at a concentration of 3.2 mM. CGA-N46 had an inhibitory effect on the proliferation of lung cancer A549 cells and a reversible effect on the growth of normal primary chicken embryo fibroblast cells, but no hemolytic activity on human erythrocytes at the minimum inhibitory concentration of CGA-N46 against yeasts. The antifungal activity of CGA-N46 was stable at a temperature <40°C or within a broad pH range (pH 5.0-7.0). Its antifungal activity was enhanced when the peptide was used in combination with fluconazole and terbinafine. The present results indicate that CGA-N46 is a safe, physicochemically stable, antifungal peptide with anticancer cell activity that exhibits an additive effect with conventional antibiotics. [ABSTRACT FROM AUTHOR]