Background: The hepatocellular carcinoma up-regulated EZH2-associated long non-coding RNA (HEIH) has been identified to act as an oncogene to promote cell tumorigenesis in hepatocellular carcinoma (HCC); however, the roles of HEIH in sorafenib resistance in HCC cells remain elusive.
Materials and Methods: The expression of HEIH and microRNA (miR)-98-5p was detected using quantitative real-time polymerase chain reaction. Cell viability, apoptosis, migration and invasion were analyzed using cell counting kit-8 assay, flow cytometry and transwell assay. Western blot was used to measure the levels of apoptosis-related protein and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway-related protein. The interaction between HEIH and miR-98-5p was confirmed by dual-luciferase reporter and RNA immunoprecipitation assay. In vivo experiments were performed using murine xenograft models.
Results: HEIH was up-regulated in sorafenib-resistant HCC tissues and cell lines, and HEIH silence weakened sorafenib resistance by suppressing cell viability, invasion and migration, decreasing the IC₅₀ values to sorafenib, and increasing apoptosis in sorafenib-resistant HCC cells in vitro and reinforced the anti-tumor effects of sorafenib in vivo. HEIH was a sponge of miR-98-5p, and miR-98-5p inhibition reversed the sorafenib sensitivity induced by HEIH deletion in sorafenib-resistant HCC cells. MiR-98-5p inhibition could activate PI3K/AKT pathway, and enhanced sorafenib resistance by regulating the activation of PI3K/AKT pathway in sorafenib-resistant HCC cells. Besides, HEIH also activated PI3K/AKT pathway through regulating miR-98-5p in sorafenib-resistant HCC cells.
Conclusion: HEIH conferred an advantage to sorafenib resistance in HCC by the activation of PI3K/AKT pathway through miR-98-5p, indicating a potential therapeutic strategy for HCC chemotherapy.
Keywords: HEIH, miR-98-5p, PI3K/AKT, HCC, chemoresistance