Somatostatin Octapeptide Inhibits Cell Invasion and Metastasis in Hepatocellular Carcinoma Through PEBP1.

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) is a major threat to human health. The condition carries a high risk of death; 45% of new cases occur in China. Surgical resection is the first choice for treatment of HCC, but 30.9% of patients experience recurrence within 6 months after the operation. To improve patient survival, we must determine how to reduce the probability of recurrence and metastasis and elucidate the underlying mechanism of disease. We therefore studied the effect of somatostatin octapeptide (octreotide) on the invasion and metastasis of HCC.

METHODS: The migration and invasion cytological tests were used to detect the effect of octreotide on liver cancer cells (SK-Hep-1 and HepG2). PEBP1 RNAi was used to knockdown expression. Invasion and metastasis were measured with transwell migration and wound-healing assays. Western blotting was used to detect changes in levels of PEBP1 and invasion pathway proteins after octreotide treatment. The effect of octreotide was studied in vivo by establishing a pulmonary metastasis model using SK-Hep-1 cells in nude mice. In-vivo bioluminescence imaging and hematoxylin and eosin staining of lung tissue were used to verify the results.

RESULTS: Increasing concentrations of octreotide were progressively more effective in halting the invasion and metastasis of liver cancer cells. Octreotide may upregulate PEBP1, TIMP-2, and E-cadherin while downregulating MMP-2 and Twist to inhibit cell invasion and metastasis. And downregulation of PEBP1 would also change the expression of MMP-2, TIMP-2 and Twist. The in-vivo experiments showed no cancer cell metastasis in 4 of the 6 mice in the octreotide-treatment group, while all of the mice in the control group displayed pulmonary metastasis of human HCC cells. And the survival period of the mice in the octreotide-treatment group was significantly prolonged.

CONCLUSIONS: Octreotide may weaken invasion and metastasis through the upregulation of PEBP1. Octreotide may reduce the risk of recurrence and metastasis after surgery for liver cancer.