microRNA-99b acts as a tumor suppressor in non-small cell lung cancer by directly targeting fibroblast growth factor receptor 3.
ABSTRACT microRNAs (miRNAs) play a significant role in cancer development and progression by regulating the expression of proto-oncogenes or tumor suppressor genes. Our previous study using microarrays demonstrated that miR-99b was downregulated in patients with lung cancer. To assess whether or not miR-99b has a functional role in lung cancer, we determined the expression of miR-99b and fibroblast growth factor receptor 3 (FGFR3), which is a predicted target of miR-99b in public algorithms in human lung cancer tissues. miR-99b was downregulated and FGFR3 was upregulated in lung cancer patients. We demonstrated that the overexpression of miR-99b induced a reduction in FGFR3 expression and confirmed the target specificity between miR-99b and the FGFR3 3'-untranslated region by luciferase reporter assay. In addition, the growth rate in miR-99b precursor-treated cells was lower compared to the negative controls. Taken together, these results suggest that miR-99b may be a tumor suppressor through the downregulation of FGFR3. miR-99b may be a potent tumor suppressor and may be a potential therapeutic tool for patients with lung cancer.
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ABSTRACT: This study examined binding sites of 2,578 miRNAs in the mRNAs of 12,175 human genes using the MirTarget program. It found that the miRNAs of miR-1273 family have between 33 and 1,074 mRNA target genes, with a free hybridization energy of 90% or more of its maximum value. The miR-1273 family consists of miR-1273a, miR-1273c, miR-1273d, miR-1273e, miR-1273f, miR-1273g-3p, miR-1273g-5p, miR-1273h-3p, and miR-1273h-5p. Unique miRNAs (miR-1273e, miR-1273f, and miR-1273g-3p) have more than 400 target genes. We established 99 mRNA nucleotide sequences that contain arranged binding sites for the miR-1273 family. High conservation of each miRNA binding site in the mRNA of the target genes was found. The arranged binding sites of the miR-1273 family are located in the 5'UTR, CDS, or 3'UTR of many mRNAs. Five repeating sites containing some of the miR-1273 family's binding sites were found in the 3'UTR of several target genes. The oligonucleotide sequences of miR-1273 binding sites located in CDSs code for homologous amino acid sequences in the proteins of target genes. The biological role of unique miRNAs was also discussed.BioMed Research International 08/2014; 2014:620530. DOI:10.1155/2014/620530 · 2.71 Impact Factor
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ABSTRACT: Non-small lung cell carcinoma (NSCLC) is a leading lethal disease and a global health burden. The function of the Sex determining region Y (SRY)-related high mobility group box (SOX) family gene in cancer has attracted the attention of more and more scientists recently, yet there are few reports regarding the role of SOX in NSCLC. Our study aimed to investigate the expression of SOX8, a protein belonging to the E group of the SOX family, as well as SOX9, in non-small cell lung cancer (NSCLC) and the relationship of gene expression to clinicopathological factors and prognosis in patients. Immunohistochemical analysis was used to measure the expression of SOX8 in 80 NSCLC and 7 adjacent normal tissues. SOX8 expression was detected as elevated in tumor samples and correlated to tumor size (P < 0.001), lymph node metastasis (P = 0.001), differentiation classification (P = 0.015), and clinical stage (P = 0.013) significantly. Moreover, Kaplan-Meier survival analysis demonstrated that shorter survival time for patients who had higher SOX8 expression (P < 0.001). In addition, our experiments indicate that miRNA-124 functions as a tumor suppressor in NSCLC. We also demonstrate miRNA-124 directly targeted and decreased SOX8 in NSCLC cell lines, suggesting smiRNA-124 may regulate NSCLC cell proliferation via decreasing SOX8 (oncogenicity of biomarker in NSCLC).
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ABSTRACT: The insulin-like growth factor 1 (IGF-1) signaling pathway regulates critical biological processes including development, homeostasis, and aging. Dysregulation of this pathway has been implicated in a myriad of diseases such as cancers, neurodegenerative diseases, and metabolic disorders, making the IGF-1 signaling pathway a prime target to develop therapeutic and intervention strategies. Recently, small non-coding RNA molecules in ∼22 nucleotide length, microRNAs (miRNAs), have emerged as a new regulator of biological processes in virtually all organ systems and increasing studies are linking altered miRNA function to disease mechanisms. A miRNA binds to 3'UTRs of multiple target genes and coordinately downregulates their expression, thereby exerting a profound influence on gene regulatory networks. Here we review the components of the IGF-1 signaling pathway that are known targets of miRNA regulation, and highlight recent studies that suggest therapeutic potential of these miRNAs against various diseases.Frontiers in Genetics 01/2014; 5:472. DOI:10.3389/fgene.2014.00472