Long-Chain Non-Coding RNAs Metastasis-Associated Lung Adenocarcinoma Transcript-1 Is Involved in Growth of Nasopharyngeal Carcinoma Cells by Targeting miR-205-5p

The incidence of nasopharyngeal carcinoma (NC) has been rising. The prognosis of NC remains unsatisfactory; therefore, it is necessary to find new ways to improve it. LncRNA MALAT1 (MALAT1) is a well-studied gene, but its status in NC remains unclear. More experimental analyses are needed to uncover the role of MALAT1 in NC for a reliable and accurate theoretical basis for NC’s diagnosis and treatment. First, NC patients admitted to our hospital from February 2018 to March 2020 and healthy controls who underwent physical examinations during the same period were enrolled in this study. MALAT1 and miR-205-5p in the patients’ peripheral blood and tissues were detected. The expression of MALAT1 was high, and the expression of miR-205-5p was low in the NC patients. Both genes were effective in predicting the occurrence of NC, and their expression was negatively correlated. According to in vitro experiments, inhibiting MALAT1 and increasing miR-205-5p could reduce CNE-2Z cells’ proliferation and increase their apoptotic rate. However, increasing MALAT1 and inhibiting miR-205-5p had opposite effects. Through the online website ENCORI, complementary sites were found in MALAT1 and miR-205-5p. According to dual-luciferase reporter gene assay, MALAT1-WT’s luciferase activity was inhibited by the co-transfection of miR-205-5p-min, while MALAT1-MUT’s luciferase activity was enhanced by the co-transfection of miR-205-5p-inh. Lastly, through rescue experiments, we found no difference in the biological behavior between the cells in the MALAT1 si-RNA+miR-205-5p-inh group and the MALAT1+NC-RNA group. Therefore, MALAT1 promotes NC cell proliferation, inhibits apoptosis, and participates in NC’s development via specifically regulating miR-205-5p.