BackgroundEsophageal squamous cell carcinoma (ESCC) is the major histological type of esophageal cancer in developing countries. The prognosis and survival rate of ESCC are very poor. Recently, microRNAs (miRNAs) have emerged as important regulators of cancer cell biological processes. To better understanding the molecular mechanisms by which they regulate the behavior of cancer cells is needed.MethodsThe expression of miR-208 was examined in ESCC cell lines and tumor tissues by real-time PCR. Proliferation capability of ESCC cells upon regulation of miR-208 expression was detected by MTT assay, colony formation assay, anchorage-independent growth ability assay and flow cytometry analysis. The target of miR-208 was determined by western blotting analysis, luciferase reporter assay and real-time PCR.ResultsmiR-208 was upregulated in ESCC cell lines and tissues. Overexpression of miR-208 in ESCC cells increased cell proliferation, tumorigenicity and cell cycle progression, whereas inhibition of miR-208 reduced cells proliferation, tumorigenicity and cell cycle progression. Additionally, SOX6 was identified as a direct target of miR-208. Ectopic expression of miR-208 led to downregulation of SOX6 protein, which resulted in the downregulation of p21, upregulation of cyclin D1 and phosphorylation of Rb.ConclusionsThese results suggest that miR-208 represents a potential onco-miR and participates in ESCC carcinogenesis by suppressing SOX6 expression.

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Maintaining a balance between convergence and diversity of the population in the objective space has been widely recognized as the main challenge when solving problems with two or more conflicting objectives.

The challenge of solving dynamic multi-objective optimization problems is to effectively and efficiently trace the varying Pareto optimal front and/or Pareto optimal set. To this end, this paper proposes a multi-direction search strategy, aimed at finding the dynamic Pareto optimal front and/or Pareto optimal set as quickly and accurately as possible before the next environmental change occurs.