lncRNA MANCR Inhibits NK Cell Killing Effect on Lung Adenocarcinoma by Targeting miRNA-30d-5p

Background. NK cells are imperative in spontaneous antitumor response of various cancers. Currently, lncRNAs are considered important modulators of the tumor microenvironment. This study investigated the molecular mechanism by which mitotically associated long noncoding RNA (MANCR) controls killing effect of NK cells on lung adenocarcinoma (LUAD) in the tumor microenvironment. Methods. The interplay between MANCR and miRNA-30d-5p was analyzed by bioinformatics. Expression of MANCR mRNA and miRNA-30d-5p was examined using qRT-PCR. Dual-luciferase reporter and RIP assays were utilized to verify the targeted relationship between MANCR and miRNA-30d-5p. To investigate regulation of MANCR/miRNA-30d-5p axis in NK cell killing effect on LUAD cells, western blot tested the protein level of perforin and granzyme B. ELISA determined the level of IFN-γ. CytoTox 96 Non-Radioactive Cytotoxicity Assay kit was applied for cytotoxicity detection of NK cells. Perforin and granzyme B fluorescence intensity was measured via immunofluorescence, and cell apoptosis levels were also revealed via flow cytometry. Results. MANCR was found to be upregulated, while miRNA-30d-5p expression was downregulated in LUAD tissues. Overexpression of MANCR in LUAD cells significantly reduced NK cell IFN-γ secretion, expression of granzyme B and perforin, and NK cell killing effect. In addition, MANCR could target and downregulate miRNA-30d-5p expression, and miRNA-30d-5p overexpression reversed the inhibition of NK cell killing effect caused by MANCR overexpression. Conclusion. MANCR inhibited the killing effect of NK cells on LUAD via targeting and downregulating miRNA-30d-5p and provided new ideas for antitumor therapy based on tumor microenvironment.