背景与目的:肝细胞痛是一种有高度新生血管的肝脏恶性肿瘤,进展期肝细胞癌的预后很差,目前缺乏有效的治疗.近来有报道肝细胞生长因子的Kringle 1结构域(HGFK1)基因具有很强的抑制新生血管的作用.本研究探讨肝细胞生长因子Kringle 1结构域(HGFK1)基因对原发性肝细胞癌的治疗作用及其机制.方法:构建携带有HGFK1基因的腺相关病毒载体(rAAV-HGFK1),建立大鼠原发性肝细胞癌模型,以rAAV-HGFK1进行治疗,继而观察大鼠原发性肝癌模型的生存时间、肿瘤生长情况、肿瘤内血管密度以及转移情况.结果:在大鼠肝脏内注射6×105个大鼠肝细胞癌细胞株McA-RH7777后,第10天全部成瘤.通过向瘤内和门静脉内注射rAAV-HGFK1导入HGFK1基因可以明显延长荷肝细胞癌大鼠的生存时间,对照组生存时间为30 d,而治疗组的生存时间为49 d.在对照的PBS注射组和AAV-EGFP注射组,肝脏和腹腔内转移的发生率都是100%;而肺转移的发生率则分别为100%和83%.而治疗组都没有转移,且腹水的发生率才只有33%.组织学证实AAV-HGFK1对肿瘤的作用则具体表现为肿瘤生长的受到抑制、肿瘤内血管密度的减少、以及发生肝内、肺、腹膜等转移机率的下降.HGFK1表现出了明显的抗血管生成及抑制肿瘤细胞生长作用.在大鼠体内的毒性实验未发现明显毒性.结论:HGFK1能通过抗血管生成作用达到抑制肝细胞癌原发灶及转移灶的效果,显著延长荷瘤大鼠的生存时间,没有发现明显的毒性,为临床抗肿瘤治疗提供了一个潜在的新靶点.%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.
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