Mechanism And Effects Of Human Ribonuclease Inhibitor On Insulin-liked Growth Factor-Ⅱ In Cancer Cell

Ribonuclease inhibitor (RI) is an acidic cytoplasmic protein with a 50 kDa estimated molecular weight. RI can inhibit the activity of ribonuclease A (RNase A) by tight combination with it (Ki=4.0×10-14M), and RI can also inhibit Angiogenin (Ang) effectively. Angiogenin has a robust capacity to induce blood vessel formation in vivo and in vitro, growth of tumor correlated with new vessels, so it in favour of the existence of Ang. RI suppress the growth of tumor cells by inhibiting the activity of Ang. RI is constructed almost entirely of leucine-rich repeats. Such repeats have been identified in more than 100 proteins that exhibit a wide range functions, including cell-cycle regulation, DNA repair, extracellular matrix interaction, and enzyme inhibition. RI located on the chromosome 11p15.5. Insulin-like growth factor -2 (IGF-2), on the same position, is mitogen. Not only IFG-2 can regulate cell growth, differentiation, apoptosis, and transform by paracrine and autocrine, but it is an important stimulating factor in signal conduction pathway. Unbalance of any process of above makes cell proliferation out of control, therefore, induces canceration. There are evidences that IGF-2 increases cell proliferation, inhibits apoptosis and raises local infiltration and transfer in many tumor cells. RI spare the nearby same position of human chromosome with IGF-2 , however, they have contradistinctive contribution. For above all, we presume that they may have some unknown interaction. We expect to further study the important role of RI in signal conduction pathway, and then provide important theory for RI's contribution of anti-tumor and anti-vascularization.The purpose of this study is to discuss the effect to IGF-2 by over-expressed RI in eukaryotic cell line, and to find out the relationship between RI and IGF-2, so as to illustrate the mechanism of anti-tumor and anti-oxidation of RI. This experiment established a infection of eukaryotic cell line: Human breast carcinoma cell line MCF-7, by retrovirus carrying...