Effects of CDK4 antisense RNA on Human breast cancer cell proliferation and expression of cyclinD1, cyclinE and CDK2

The role of CDK4 in human breast cancer cell proliferation and expression of cyclinD1, cyclinE and CDK2 has been investigated using inhibition of CDK4 expression by antisense RNA. When CDK4 expression was inhibited, the rate of cell proliferation and tumorigenecity decreased apparently. This indicates that CDK4 plays an important role in formation and development of breast tumor. The results of Northern blot analysis showed that the levels of cyclinDl and CDK2 mRNAs changed slightly whereas the level of cyclinE mRNA decreased obviously. It is suggested that the expression of CDK4 is necessary for imction of cyclinE expression. Thus, inhibition of CDK4 expression affects not only the role of CDK4 itself but also the role of other genes.