LncRNA FOXD3-AS1 Mediates AKT Pathway to Promote Growth and Invasion in Hepatocellular Carcinoma Through Regulating RICTOR.

Hepatocellular carcinoma (HCC) has high morbidity and mortality, but current therapeutic methods cannot effectively improve patient's prognosis. FOXD3-AS1, a new identified long noncoding RNA, is dysregulated in several cancers and functions as a carcinogenic or tumor-suppressor factor. However, the function of FOXD3-AS1 in HCC has not been reported. Quantitative real time-polymerase chain reaction was applied to evaluate the expression of FOXD3-AS1 in HCC tissues and cell lines. miRDB and TargetScan websites were utilized to predict the interaction network of FOXD3-AS1 as a competing endogenous RNA. The interaction was confirmed by luciferase reporter assay and RNA binding protein immunoprecipitation (RIP) assay. The effect of FOXD3-AS1 on HCC cells (Huh6) were measured by cell counting kit (CCK)-8, BrdU cell proliferation assay, Transwell invasion assay, and wound healing assay. FOXD3-AS1 was overexpressed in HCC, and HCC patients with the high level of FOXD3-AS1 had a poor prognosis. In addition, FOXD3-AS1 knockdown considerably inhibited the proliferation, migration, and invasion of Huh6 cells. Besides, FOXD3-AS1 functioned as a sponge of miR-335, and was a direct target gene of miR-335. Furthermore, FOXD3-AS1 could enhance the level of RICTOR through sponging miR-335. Moreover, the knockdown of FOXD3-AS1 could competitively bind with miR-335 to suppress RICTOR expression, thereby inhibiting the growth of Huh6 cells through the deactivation of AKT signaling pathway. FOXD3-AS1 is crucial for the tumorigenesis and progression of HCC. The interaction among FOXD3-AS1, miR-335, and RICTOR provides a novel insight for understanding the molecular mechanism of HCC, and FOXD3-AS1, miR-335, and RICTOR can be regarded as the potential targets for HCC treatment.