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Introduction: Melanoma is a deadly malignancy and the poor prognosis of patients with advanced disease is relatively poor. Recent studies indicate that long non-coding RNAs are involved in the pathogenesis of malignant melanoma. This study aims to investigate the role of the long non-coding RNA H19 in melanoma and to explore the underlying molecular mechanisms. Materials and methods: The expression levels of H19 in clinical samples and melanoma cells were determined by quantitative real-time PCR. The cell growth and cell metastasis were assessed by Cell Counting Kit 8, cell invasion and wound healing assays. Cell apoptosis and cell cycle were determined by flow cytometry. Protein levels were determined by Western blotting assay. Results: H19 was highly expressed in melanoma tissues compared to normal adjacent skin tissues, and the tissue expression level of H19 from melanoma patients with metastasis was significantly higher than that from patients without distant metastasis. In addition, the high expression of H19 in melanoma tissues was associated with advanced tumor invasion and TNM stage, distal metastasis, lymph node metastasis and shorter overall survival in patients with melanoma. The in vitro functional assays showed that knockdown of H19 inhibited cell growth, invasion and migration and also induced cell apoptosis as well as G0/G1 arrest in melanoma cells. Further quantitative real-time PCR and Western blot experiments showed that knockdown of H19 differentially regulated the epithelial–mesenchymal transition (EMT)-related gene expressions and reversed EMT in melanoma cell lines. Knockdown of H19 suppressed in vivo tumor growth and modulated the expressions of EMT-related genes in nude mice. Conclusion: The results from this study suggest that upregulation of H19 contributes to melanoma development and progression. [ABSTRACT FROM AUTHOR]

Objective: In order to study the structure and function of beta2 microglobulin (beta2 m)., Methods: We sub-cloned the mature peptide of beta2 m into the p2X plasmid and transformed them to Escherichia coli TB1. The recombinant bacterium was induced to be expressed and the expressed fusion protein was detected by SDS-PAGE and western blot. After purifying and cleaving with Factor Xa, we separated the monomer protein beta2 m from MBP. Finally, we determined the secondary structure of the beta2 m protein by circular dichroism (CD) spectrum., Results: MBP-beta2 m was 52.1 kDa, and the monomer protein beta2 m was 10.6 kDa. The alpha-helix, beta-sheet, turn, and random coil of the fusion protein showed 0, 45, 8 and 45 amino acids, respectively, detected by CD estimation., Conclusion: The beta2 m protein had correct secondary structure and could be used for further research of peptide binding in vitro.