The long noncoding RNA AK002107 negatively modulates miR-140-5p and targets TGFBR1 to induce epithelial-mesenchymal transition in hepatocellular carcinoma.

The abnormal expression of long noncoding RNAs (lncRNAs) is associated with human carcinoma. The present study aimed to investigate the mechanisms underlying the function of lncRNA AK002107 in the progression of hepatocellular carcinoma (HCC). The differential expression of lncRNAs between HCC and paired nontumor tissues was identified using microarrays, and the correlation between the expression of lncRNA AK002107 and the clinical prognosis of HCC was analyzed. We investigated the role of lncRNA AK002107 in HCC tumor biology in vitro using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT), colony formation, and Matrigel invasion assays and in vivo by assessing the growth of xenografted HCC tumors. The potential microRNAs that interact with lncRNA AK002107 were identified using online tools and were verified using PCR and luciferase reporter assay. The levels of TGFBR1, E-cadherin, and vimentin were determined using western blot assays. We then further investigated the correlation between expression of lncRNA AK002107 with miR-140-5p and TGFBR1 expression in HCC tissues. The expression of lncRNA AK002107 is frequently upregulated in HCC samples and cell lines. Patients with HCC who have elevated lncRNA AK002107 expression exhibit poorer overall survival and disease-free survival. Silencing lncRNA AK002107 expression significantly inhibited HCC cell proliferation, colony formation, and invasion both in vitro and in vivo. Furthermore, lncRNA AK002107 directly binds to miR-140-5p and significantly inhibits miR-140-5p expression. The functions of lncRNA AK002107 in cell growth and tumor invasion are mediated via miR-140-5p. lncRNA AK002107 upregulated TGFBR1 expression and then induced epithelial-mesenchymal transition (EMT) by inhibiting miR-140-5p expression. The expression of lncRNA AK002107 inversely correlated with miR-140-5p expression and positively correlated with TGFBR1 expression in HCC tissues. In summary, lncRNA AK002107 functions as an oncogene in tumors by inhibiting miR-140-5p, targeting TGFBR1, and then inducing EMT. The lncRNA AK002107/miR-140-5p/TGFBR1/EMT regulatory network may be a valuable target for the development of novel diagnostic and treatment methods for HCC.