| Angiogenesis was an important pathological process in a number of conditions,especially in the malignant diseases. A typical growth of new capillary had been found to be out of control and persistent in the tumors. In the solid malignant tissue, the neovascularization was constantly induced by the angiogenic factors from the normal host cells and tumor cells itself. Tumor cell received nutrients and remove wastes via newly formed capillaries. Therefore, angiogenesis is essential for the development and translocation of tumor cells. Some in vivo studies had indicated that several inhibitors specific to the different angiogenic factors could inhibit the tumor growth and metastasis. Today, the development of inhibitors of angiogenesis has been an attractive new therapeutic approach to the anticancer treatment.Now several angiogenic proteins such as basic fibroblast growth factor, vascular endothelial growth factor and angiogenin(ANG) had been found to be involved in tumor angiogenesis. Among them, ANG, a heparin-binding protein being 35% homologous in amino acid sequence to pancreatic RNase, which was first isolated from culture medium of tumor cells, had been identified as a potent inducer of neovascularization. It played a critical role in the processes of angiogenesis, including supporting endothelial, stimulating the second messenger, inducing cell invasion and activating cell-associated proteases, etc.. Different tumor tissues and cell lines could express ANG mRNA to stimulate forming of new vessels during the course of tumor development. The blood level of ANG in tumor sufferers was almost sonsistent with the malignant degree. Thus ANG could be as a good target for developingthe angiogenesis antagonists. If tumor angiogenesis were inhibited, the development of tumor even killing tumor cells could be achieved.In the last years, ANG antagonists, including monoclone antibody(mAb) 26-2F, peptide antagonists of ANG ANI-E and soluble binding-protein-actin had showed the inhibit effects on the human tumors growth in SCID mice and could reduce or eleminate neovascular formation in tumor tissue. Since most of these antagonists designed to aim at different points of angiogenesis course and acted on the ANG protein, they sometimes were inefficient due to they were easy to be interfered by condition factors, furthermore, they could often bring some nonspecific effects.Recently, antisense oligonucleotide technology was introduced into the antiangiogenesis study. As a new strategy it offers a useful tool and showed a bright future in the study. This technology was based on the base match principal that antisense oligonucleotide could especially designed to prevent gene replication or translation by combining specifically with target DNA or RNA. Because the act site was on the upriver in the synthesization of ANG protein, antisense oligonucleotide could effectually and specifically block out expression of target gene. We adopted antisense technology to investigate the antiangiogenesis and antitumor effects of ANG antisense oligonucleotide in this study. Through the in vitro and in vivo study, we discussed the possibility that whether the ANG antisense oligonucleotide synthesized by us could be as a new antitumor drug.Methods:1. Transfection of human ANG antisense oligonucleotide into human lung cancer cell Hne-A549, and its' effects on the cancer cells.Human lung cancer cell line A549 was cultured and used in this study. The antisense oligonucleotide aimed to the start sequence of ANG mRNA wastransfected to A549 cells by cationic liposome. To improve the transfecting efficiency, the transfection time and the dosage of cationic liposome were determined by morphological observation of tumor cell and Dot-ELISA. The expression of ANG protein in A549 cells was detected by immunohisto-chemistry and the ANG protein in culture medium was analyzed by ELIS A. 2. The anticancer effects of human ANG antisense oligonucleotide on the tumor growth in SCID mice.On the base of results obtained from the in vitro st... |
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