Hepatic gene expression of NK4, an HGF-antagonist/angiogenesis inhibitor, suppresses liver metastasis and invasive growth of colon cancer in mice

Abstract

Hepatocyte growth factor (HGF) is involved in malignant behavior of cancer cells by enhancing invasion and metastasis. We earlier found that NK4, a four-kringle fragment of HGF, functions as both an HGF antagonist and an angiogenesis inhibitor. We have now carried out studies to determine if hydrodynamics-based delivery and expression of the NK4 gene would inhibit liver metastasis and invasive growth of colon carcinoma cells in mice. When the naked plasmid for NK4 was introduced into mice by hydrodynamics-based gene delivery, a high level of expression of NK4 was predominant in the liver. After intrasplenic inoculation of MC-38 murine colon carcinoma cells, the cells formed numerous metastatic nodules in the liver and showed invasive growth behavior. On the other hand, when mice were given the NK4 plasmid, hepatic gene expression of NK4 inhibited the liver metastasis and subsequent growth associated with a decrease in microvessel density. Likewise, intrahepatic invasion of cancer cells was inhibited by NK4 gene expression, and this anti-invasive effect was associated with in situ inhibition of c-Met receptor tyrosine phosphorylation. Moreover, NK4 gene expression prolonged survival of these mice. Taken together with the knowledge that the majority of deaths from colon cancer are due to liver metastasis, the potential therapeutic use of hepatic gene expression of NK4 for metastatic colon cancer treatment can be given consideration.

Hepatocyte growth factor and the Met system as a mediator of tumor–stromal interactions

“…29 Likewise, the Met receptor was in situ tyrosine-phosphorylated in invasive carcinomas in mice, whereas the inhibition of Met tyrosine phosphorylation was associated with the suppression of the invasive behavior. 30 These results indicate that the in situ activation of Met is associated with the invasive and metastatic progression of cancers.…”

Suppression of metastasis of human pancreatic cancer to the liver by transportal injection of recombinant adenoviral NK4 in nude mice

“…[28][29][30][31][32] These data indicate that NK4 is certainly effective for various types of carcinoma.…”

Inhibition of angiogenesis and HGF-cMET-elicited malignant processes in human hepatocellular carcinoma cells using adenoviral vector-mediated NK4 gene therapy

“…39 So far, NK4 gene therapy has demonstrated efficacy in tumor models in which the involvement of the HGF-cMET signaling pathway in pathogenesis has been clearly established. [8][9][10][11][12][13][14][15][16][17][18][19][20] Based on the multifunctional properties of NK4 on various growth factors, 3,4,12,40 we propose that NK4 gene therapy would have therapeutic value for a wider range of tumors than only cMET overexpressing carcinomas. However, application of NK4 gene therapy to specific tumor types such as HCC for which the effect of the HGF-cMET signaling is less explicit or may even be inhibitory on carcinogenesis [32][33][34] needed further assessment.…”

“…Potential improvements include readministration of adenoviral vectors without challenging neutralizing immunity, application of selectively replicating adenoviral vectors expressing NK4 to overcome low tumor transduction and to gain effect by high level production of NK4 plus the inherent oncolytic property of these viruses, [42][43][44][45] and other treatment strategies such as using the liver as systemic supplier of NK4. 8,17 Obviously, further development of NK4 gene therapy for HCC should also include safety evaluation in animal models of cirrhotic liver and chemical hepatocarcinogenesis representing the pathogenesis of human HCC, and examination of toxicity of NK4 on angiogenesis during normal processes like wound healing. In this regard, it is reassuring that trials with other antiangiogenic factors such as angiostatin and endostatin, have been shown to inhibit tumor angiogenesis with little or no effect on wound healing in mice.…”

“…[3][4][5][6] NK4, which consists of the N-terminal hairpin domain and the four subsequent kringle domains of HGF, competitively inhibits the multiple biological activities of HGF through binding to cMET and is suggested to have a broad antiangiogenic activity through its kringle domain structure. 3,4,7 Previous in vivo studies confirmed therapeutic efficacy of NK4 gene therapy for glioblastoma, prostate, breast, gastric, pancreatic, gall bladder and colon cancers [8][9][10][11][12][13][14][15][16][17][18][19][20] and recommended further preclinical evaluation of NK4 gene therapy as anticancer agent. However, NK4 gene therapy for treatment of HCC could be argued against because the antitumor effects of NK4 in part rely on its antagonistic activity to HGF 3 and the role of the HGF-cMET system in hepatocarcinogenesis has not been clearly established.…”