[Expression and activation of MAPK pathway signaling molecules in human breast cancer cell lines].

Aim: To detect the expression and status of extracellular regulatory kinase 1 and 2 (ERK1/2) and its upstream kinase MEK1/2 proteins in four breast cancer cell lines MCF-7, Bcap-37, SK-BR-3 and T47D and study the effects of cyclophosphamide and epirubicin on the growth of the cell lines and on the expression and status of the signaling molecules.

Methods: Western blot was used to examine the expression and status of MEK1/2 and ERK1/2 proteins in these cells and the effects of these two drugs on them. The effects of the two drugs on the proliferation of these breast cancer cell lines were detected by MTT colorimetry.

Results: The levels of expression and phosphorylation of MEK1/2 and ERK1/2 proteins in four breast cancer cell lines increased notably as compared with those in MCF-10 cells. Both drugs could inhibit the proliferation of breast cancer cells. And the levels of expression and phosphorylation of MEK1/2 and ERK1/2 proteins in breast cancer cell lines treated with the drugs were markedly lower than those in untreated breast cancer cells.

Conclusion: Overexpression and phosphorylation of MEK and ERK may play an important role in the generation and development of human breast cancer. The inhibitory effect of cyclophosphamide and epirubicin on proliferation of the breast cancer cells may be by means of inhibiting expression and phosphorylation of MEK and ERK.