Adenovirus-mediated NK4 gene therapy suppresses hepatocellular carcinoma.

肝细胞生长因子（HGF）作为肿瘤间质相互作用的介质参与肿瘤的恶性行为，增强侵袭和转移。NK 4是HGF的内部片段，作为血管生成抑制剂以及HGP拮抗剂起作用。本研究旨在评估NK 4基因治疗肝细胞癌（HCC）的潜力，肝细胞癌是全球最常见的恶性肿瘤之一。本研究使用人HCC细胞（Huh 7）。用重组腺病毒（Ad-NK 4）介导NK 4基因转导。为了评价NK 4作为HGF拮抗剂的功能，研究了Ad-NK 4对HCC细胞体外生物学行为的影响。将Huh 7细胞皮下注射到裸鼠中以建立皮下肿瘤。肿瘤接种后10天，连续2天将Ad-NK 4注射到肿瘤中。对照动物接受磷酸盐缓冲盐水（PBS）或Ad-LacZ。接下来，将HuH 7细胞注射到严重联合免疫缺陷（SCID）小鼠的门静脉中以建立肝肿瘤。肿瘤接种后第2天，经静脉注射Ad-NK 4或Ad-LacZ。在肿瘤接种后30天进行肝肿瘤的组织学检查。NK 4抑制HGF诱导的Huh 7细胞c-Met磷酸化，而NK 4不影响细胞生长。而NK 4则抑制HGF诱导的细胞侵袭和迁移。NK 4转染显著抑制皮下肿瘤的生长，并且在肿瘤中识别细胞凋亡。CD 31免疫组化染色结果显示，转染NK 4的肿瘤血管生成明显受到抑制。在肝肿瘤模型中，NK 4转染显著抑制了肝肿瘤的生长并提高了存活率。在转染NK 4的肝肿瘤中也观察到血管生成的抑制。NK 4基因治疗通过抑制血管生成显著抑制肿瘤生长。这种疗法似乎对HCC的治疗有很大的潜力。

Hepatocyte growth factor(HGF) is involved in malignant behavior of cancers as a mediator in tumor-stromal interaction, enhancing invasion and metastasis. NK4, is an internal fragment of HGF, acts as an angiogenesis inhibitor as well as an HGP antagonist. This study was designed to assess a potential of NK4 gene therapy for hepatocellular carcinoma(HCC) that is one of the most common malignant neoplasm worldwide. Human HCC cells(Huh7) were used for this study. NK4 gene transduction was mediated by recombinant adenovirus(Ad-NK4). To assess a function of NK4 as an HGF antagonist, the effects of Ad-NK4 on the biological behavior of HCC cells were studied in vitro. Huh7 cells were subcutaneously injected in nude mice to establish s.c.tumors. Ten days after tumor inoculation, the animals were injected Ad-NK4 into tumor 2 consecutive days. Control animals were received ph osphate-buffered saline(PBS) or Ad-LacZ. Next, HuH7 cells were injected into the portal vein in severe combined immunodeficiency(SCID) mice to establish a hepatic tumor. Two days after tumor inoculation, Ad-NK4 or Ad-LacZ was injected intraveneouly. Histological examination of liver tumor was performed at 30 days after tumor inoculation. NK4 inhibited HGF-induced phosphorylation of c-Met in Huh7 cells whereas NK4 did not affect on cell growth. On the contrary, invasion and migration induced by HGF were inhibited by NK4. NK4 transfection markedly suppressed growth of s.c.tumors, and apoptosis was recognized in the tumor. As the result of immunohistochemical staining of CD31, angiogenesis was obviously inhibited in the tumor that was transfected NK4. In liver tumor model, NK4 transfection significantly inhibited the growth of tumors in the liver and improved survival. Inhibition of angiogenesis was also seen in the liver tumor that was transfected NK4. NK4 gene therapy markedly suppressed tumor growth by inhibiting angiogenesis. This therapy seems to have great potential for the treatment of HCC.