MicroRNA-203 promotes liver regeneration after partial hepatectomy in cirrhotic rats

Liver resection or partial hepatectomy (PH) is still the most commonly used therapeutic option for hepatocellular carcinoma (HCC) at present. However, the impaired regenerative ability induced by the accompanied liver cirrhosis is an important risk factor of posthepatectomy liver failure, and posthepatectomy liver failure is a feared complication that accounts for up to 75% of mortality after extensive liver resection. MicroRNA(miR)-203 is a tumor suppressor of HCC and may act as a positive intermediary in A20-enhanced interleukin (IL-6)/signal transducer and activator of transcription 3 (STAT3) pro-proliferative signals, which may promote liver regeneration after PH. However, its direct pro-proliferative effect on cirrhotic liver after hepatectomy is unknown.

Liver cirrhosis was induced by intraperitoneal injection of 50% CCl4-olive oil solution in adult male Wistar rat. Rats with liver cirrhosis received portal vein injection of physiological saline, miR-203 lentivirus, or control empty lentivirus, and then 70% PH was performed under ether anesthesia 7 d later. Liver samples were harvested at 0, 24, 36, and 72 h after 70% PH. Hepatic expressions of cyclin D1 and Ki67 were checked to evaluate the liver regenerative ability. Hepatic expressions of IL-6, suppressor of cytokine signaling 3 (SOCS3), and phospho-STAT3 were also tested to clarify the mechanisms of miR-203 in liver regeneration.

The regeneration of miR-203 overexpression cirrhotic liver after 70% PH was enhanced and peaked at 24 and 36 h after 70% PH. The cyclin D1-positive liver cells/high-power field (HPF) in miR-203 overexpression liver markedly increased at 24 and 36 h after 70% PH compared with 0-h samples. When comparing with the control groups, cyclin D1-positive liver cells/HPF in miR-203 overexpression liver were also significantly increased at 24 and 36 h after 70% PH. A similar result of the Ki67-positive liver cells/HPF was achieved at 36 h after 70% PH. The hepatic expression of IL-6 showed a rising tendency after 70% PH, and the levels of IL-6 are significantly higher in miR-203 overexpression livers. Hepatic expression of SOCS3 was negatively expressed with hepatic miR-203 expression level, and the reduced expression of SOCS3 facilitated the phosphorylation of STAT3.

By targeting SOCS3 and then enhancing proliferating IL-6/STAT3 signaling pathway, hepatic overexpression of miR-203 can facilitate the initiation of liver regeneration and enhance the potency of liver regeneration after 70% PH in cirrhotic rat. Together with the tumor suppressive effect on HCC, miR-203 would be an ideal candidate for promoting liver regeneration in HCC patients undergoing liver resection without the risk of tumorigenesis or cancer recurrence.