MicroRNA-21 suppresses PTEN and hSulf-1 expression and promotes hepatocellular carcinoma progression through AKT/ERK pathways

• miR-21 suppresses the expression of hSulf-1 and PTEN in HCC cells.
• Suppression of hSulf-1 or PTEN by miR-21 can activate AKT/ERK1/2 signaling.
• Activation of AKT/ERK1/2 pathways induces EMT in HCC cells.
• miR-21 functions to promote cancer cell proliferation and movement.

MicroRNAs (miRNAs) have been believed to associate with malignant progression including cancer cell proliferation, apoptosis, differentiation, angiogenesis, invasion and metastasis. However, the functions of miRNAs are intricate, one miRNA can directly or indirectly target multiple genes and function as oncogene or tumor suppressor gene. In this study, we found that miR-21 inhibits PTEN and human sulfatase-1 (hSulf-1) expression in hepatocellular carcinoma (HCC) cells. The hSulf-1 is a heparin-degrading endosulfatase, which can inhibit the heparin binding growth factor-mediated signaling transduction into cells. Therefore, miR-21-mediated suppression of both hSulf-1 and PTEN led to activation of AKT/ERK pathways and epithelial–mesenchymal transition (EMT) in HCC cells, and finally enhance the activity of HCC cell proliferation and movement and promote HCC xenograft tumor growth in mouse models. These findings may provide candidate targets for prevention and treatment of HCC.