engleski

Influence of the protein p27 transduction on cell proliferation

Cell cycle is an interval between two cell divisions. Cell cycle is devided in the four phases: G1, S, and G2 I M phase. Proliferation of the cells through the cell cycle is regulated by internal and external signals which coordinate numerous events, which occur during different phases in cell cycle. There are many regulatory points that control passing through the cell cycle (G1/S transition is regulated by restriction point). Positive regulators of the cell cycle are cyclins and cyclin dependent kinases. Each phase of the cell cycle is characterized by the expression of different cyclin/cdk complex, which phosphorylate different substrates. Cip/Kip and Ink4 are negative regulators of the cell cycle. Cip/Kip proteins (p21Cip1, p27Kip1 and p57Kip2) bind cyclin/cdk complexes inhibiting their function. p27Kip1 is a tumor suppressor which inhibits G1/S transition by binding cyclin E/cdk2 complex. In this study we were investigating influence of the proteins responsible for the regulation of the cell cycle on the cell proliferation and apoptosis. For delivering of proteins to the cell we used transduction, a method which is described as a direct delivery of the proteins/peptides and their complexes from extracellular matrix into the cell. TAT-p27 wt, TAT-pt p27 i TAT-N´-p27 fusion proteins were transduced in the different cell lines in order to investigate their influence on the cell proliferation, apoptosis and expression of different proteins, which regulate the cell cycle and apoptosis. Our results have shown that influence of investigated fusion proteins on the cell cycle and apoptosis depends on the transduced protein and cell line in which the protein was transduced. In RKO cell line, TAT fusion proteins decreased expression of the cyclin D1 and E, which are involved in the regulation of cell cycle. Furthermore, TAT fusion proteins increased fragmentation of PARP and caspase-3 expression. Presence of the fragments of PARP protein (24 i 89 kDa) is considered as a proof for the apoptosis. Transduced fusion proteins (TAT-p27, TAT-pt p27 and TAT-N'-p27) don't influence on the level of intracellular p27. Using method of the protein transduction it is possible to deliver physiologically functional protein into the cell, and therefore this method could find it's application in the tumor therapy.

p27; apoptosis; cell lines; transduction

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