Long non-coding RNA (
lncRNA) ADAM
metallopeptidase with
thrombospondin type 1 motif 9
antisense RNA 2 (ADAMTS9-AS2) is involved in various types of
cancer, such as
ovarian cancer,
lung cancer and
clear cell renal cell carcinoma. However, the roles of ADAMTS9-AS2 in
liver cancer are not completely understood. The present study aimed to determine the functional role of ADAMTS9-AS2 in human
liver cancer and investigate the potential underlying molecular mechanisms. The expression levels of ADAMTS9-AS2 and ADAMTS9 were determined following ADAMTS9-AS2 overexpression and knockdown. The results indicated that ADAMTS9-AS2 overexpression and knockdown increased and decreased ADAMTS9
mRNA and
protein expression levels, respectively, indicating that alterations in ADAMTS9 expression corresponded with ADAMTS9-AS2 expression. Subsequently, the effects of ADAMTS9-AS2 on
liver cancer cell proliferation, migration and invasion were analyzed by performing Cell Counting Kit-8, wound healing and Transwell assays, respectively. The results demonstrated that ADAMTS9-AS2 inhibited
liver cancer cell proliferation, migration and invasion. Finally, the effect of ADAMTS9 on PI3K/AKT/mTOR signaling pathway-associated
proteins [AKT, phosphorylated-AKT, phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit β (PIK3CB), mTOR and phosphorylated-mTOR], several key
autophagy-related proteins [light chain 3-I/II (LC3-I/II),
beclin 1 (BECN1) and sequestosome 1 (SQSTM1)] and apoptosis-related
proteins (Bax and Bcl-2) was detected via western blotting. The results suggested that ADAMTS9-AS2 downregulated the phosphorylation of AKT and mTOR, the
protein expression level of PIK3CB, as well as the expression levels of autophagy
protein SQSTM1 and antiapoptotic
protein Bcl-2. By contrast, ADAMTS9-AS2 upregulated the expression levels of autophagy
proteins LC3-II and BECN1, and the proapoptotic
protein Bax. Collectively, ADAMTS9-AS2 inhibited
liver cancer cell proliferation, migration and invasion via inhibiting the PI3K/AKT/mTOR signaling pathway. The present study provided a novel insight into the role of ADAMTS9-AS2 in
liver cancer.