Hsa_circ_0088036 promotes tumorigenesis and chemotherapy resistance in hepatocellular carcinoma via the miR-140-3p/KIF2A axis.

Background: Hepatocellular carcinoma (HCC) is a cancer with high morbidity and mortality. There are limited treatment options, particularly for chemotherapy-resistant HCC patients. Circular RNA hsa_circ_0088036 was associated with the development of bladder cancer and non-small cell lung cancer. However, whether it might be a potential therapeutic target for HCC remains elusive.

Methods: Hsa_circ_0088036 expression was detected in HCC tumor tissues and cell lines using real-time PCR. The influences of hsa_circ_0088036 on proliferation and invasion as well as chemotherapy sensitivity in HCC cells were investigated by gain- and loss-of-function analyses. Associations among hsa_circ_0088036, miR-140-3p, and KIF2A were validated by real-time PCR, miRNA pull-down assay, dual-luciferase reporter assay, and western blot. Furthermore, a rescue experiment using KIF2A overexpression was performed to evaluate the regulatory mechanism of hsa_circ_0088036 in HCC cells. Additionally, the effect and mechanism of hsa_circ_0088036 were confirmed in a xenograft mouse model.

Results: Hsa_circ_0088036 was highly expressed in HCC tissues and cells, with even higher expression in oxaliplatin-resistant cells. This expression was positively correlated with tumor size and TNM stage of the patients. Overexpression of hsa_circ_0088036 promoted the proliferation and invasion of HCC cells, while silencing mediated the opposite effects. Meanwhile, knockdown of hsa_circ_0088036 enhanced chemotherapy sensitivity, including oxaliplatin, doxorubicin, and sorafenib, in HCC cells. Furthermore, hsa_circ_0088036 silencing inhibited tumor growth and increased oxaliplatin sensitivity in vivo. Mechanically, hsa_circ_0088036 functioned via the miR-140-3p/KIF2A axis with the activation of PI3K/Akt and Notch signaling pathways.

Conclusions: Hsa_circ_0088036 promoted HCC tumorigenesis and chemotherapy resistance by activating the PI3K/Akt and Notch pathways through regulating miR-140-3p/KIF2A signaling. Thus, hsa_circ_0088036 may be a potential therapeutic target in chemotherapy-resistant HCC.