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Feasible and efficient tissue culture plays an important role in plant genetic engineering. Wheat (Triticum aestivum L.) immature embryos (IMEs) are preferred for tissue culture to mature embryos (MEs) because IMEs easily generate embryogenic callus, producing large number of plants. The molecular mechanisms of regulation and the biological pathways involved in embryogenic callus formation in wheat remain unclear.Here, microRNAs (miRNAs) potentially involved in embryogenic callus formation and somatic embryogenesis were identified through deep sequencing of small RNAs (sRNAs) and analyzed with bioinformatics tools. Six sRNA libraries derived from calli of IMEs and MEs after 3 d, 6 d, or 15 d of culture (DC) were constructed and sequenced. A total of 85 known miRNAs were identified, of which 30, 33, and 18 were differentially expressed (P< 0.05) between the IME and ME libraries at 3 DC, 6 DC, and 15 DC, respectively. Additionally, 171 novel and 41 candidate miRNAs were also identified, of the novel miRNA, 69, 67, and 37 were differentially expressed (P< 0.05) between the two types of libraries at 3 DC, 6 DC, and 15 DC, respectively. The expression patterns of eight known and eight novel miRNAs were validated using quantitative real-time polymerase chain reaction. Gene ontology annotation of differentially expressed miRNA targets provided information regarding the underlying molecular functions, biological processes, and cellular components involved in embryogenic callus development. Functional miRNAs, such as miR156, miR164, miR1432, miR398, and miR397, differentially expressed in IMEs and MEs might be related to embryogenic callus formation and somatic embryogenesis. This study suggests that miRNA plays an important role in embryogenic callus formation and somatic embryogenesis in wheat, and our data provide a useful resource for further research.

Cervical cancer pathogenesis is regulated by numerous factors, including microRNAs. MicroRNA 1246 (miR-1246) has been shown to serve a role in cervical cancer tumorigenesis. However, the mechanisms through which miR-1246 exerts its oncogenic effects are largely unknown. The aim of the current study was to evaluate the effects of lentivirus-mediated miR-1246 knockdown on the biological characteristics and behavior of cervical cancer cells, and to identify the downstream signaling pathways affected by miR-1246 knockdown. Short hairpins inhibiting miR-1246 were synthesized and cloned into a recombinant lentiviral vector (LV-miR-1246-Inh), which was then used to infect SiHa cervical cancer cells. The effects of LV-miR-1246-Inh infection on cell invasion, proliferation and apoptosis were evaluated by Transwell assay, Cell Counting Kit-8 assay and flow cytometry, respectively. Thrombospondin-2 (THBS2), matrix metalloproteinase 2 (MMP2), MMP9 and extracellular matrix (ECM) component expression levels were evaluated, and the growth of xenograft tumors formed following injection of SiHa cells with knockdown of miR-1246 was assessed. miR-1246 downregulation in SiHa cells decreased proliferation, induced apoptosis and upregulated THBS2 expression. Furthermore, MMP2 and MMP9 levels were downregulated, whereas components of the ECM were upregulated subsequent to miR-1246 knockdown, indicating that this miRNA regulates cervical cancer cell pathogenesis via the THBS2/MMP/ECM pathway. Notably, SiHa cells with miR-1246 downregulation had a markedly decreased ability to form tumors in vivo. These results suggest that miR-1246 functions during cervical cancer pathogenesis and tumor formation via the THBS2/MMP/ECM signaling pathway. These findings support the future use of miR-1246 suppression in the treatment of cervical cancer. [ABSTRACT FROM AUTHOR]