Study of adeno-associated virus carrying the HGFK1 gene(AAV-HGFK1) in treating rat hepatocellular carcinoma / 中国癌症杂志

ABSTRACT

Background and purpose: Hepatocellular carcinoma (HCC) is a hypervascular tumor associated with a poor prognosis and lack of effective treatments. Consequently, identifying novel therapeutic strategies are urgently needed. We have previously shown that the kringle 1 domain of human hepatocyte growth factor (HGFK1) is a more effective anti-angiogenesis molecule than angiostatin. In this study, we observed the effects and mechanisms of HGFK1 gene on the HCC. Methods: A recombinant adeno-associated vires carrying the HGFK1 gene (rAAV-HGFK1) was constructed.HCC of rat was induced by McA-RH7777. rAAV-HGFK1 was used to treat the rat, median survival time and metastasis rate were observed. Results: Ten days after tumor cell inoculation, surgery were performed to confirm the tumor formation, PBS, rAAV-EGFP or rAAV-HGFK1 was injected directly into the tumor nodule followed by portal vein injection. Results from our study demonstrated that rAAV-HGFK1 treatment significantly prolonged the median survival time of the HCC bearing rats from 30 days (PBS and rAAV-EGFP groups) to 49 days (rAAV-HGFK1 group). More importantly rAAV-HGFK1 inhibited tumor growth and completely prevented liver, lung and peritoneal metastasis. In the controlled PBS and AAV-EGFP group, liver and peritoneal metastasis rate were both 100%, and lung metastasis rate was 100% and 83%, respectively. While there was no metastasis found in treatment group, with only 33% of ascites happened. This was most possibly due to the primary tumor in liver but not due to the metastasis. Moreover, at a higher magnification (1000×), it was clear that the HGFK1 protein was expressed mainly in the cytoplasma of liver cells. In parallel, IHC staining of CD31 also demonstrated a significantly lower level of microvessel density (MVD) (6.21±1.6) in the liver tumor of the AAV-HGFK1 treatment group, as compared to the two control PBS and AAV-EGFP groups (25.1±2.1 and 26.8±2.5, respectively, P<0.01). HE staining showed that AAV-HGFK1 treatment induced large areas of necrosis in the tumor tissues, while minimal areas of necrosis were observed in the tumor tissue in the control groups. In addition, no toxicity appeared when high dosage (4.8× 1012 vg/rat) of rAAV-HGFK1 was administered in rats. Conclusion: Results from this study demonstrated that HGFK1 inhibited the growth and metastasis of HCC and prolonged the survival time of animals with HCC through anti-angiogenesis effects. No obvious toxicity was observed. It might be the novel promising treatment for HCC and other cancers.