An Experimental Study About The Effect Of Hepatoma Cells' Adhesion And Contraction On Rho Proteins Expression

Rho proteins are the key factors in cell signal transduction pathway, may be involved in the regulation of normal cell proliferation, differentiation and apoptosis, and its expression may be received feedback regulation by the cytoskeleton functional status. In a variety of tumor cells, high expression of Rho proteins associated with the tumor occurrence and metastasis. As a result of tumor cells cytoskeleton deficiencies, this led to the dysfunctional cytoskeleton and high expression of Rho proteins, and whether the relevance of these exists. In this research, we studied the effects on Rho proteins expression and cell migration with the different cell adhesion form and contraction state; therefore can explore the mechanism of hepatoma cell invasion and metastasis.Object In this paper reviewed the changes of Rho proteins expression in the trend by controlling cell adhesion and contraction behaviors in hepatic cells and hepatoma cells with the different prestress state, and this effect on the cell proliferation and migration characteristics, thereby can provide certain significance on the molecular basis in hepatoma cells migration.Methods Using microscopic morphological observation and immuno- histochemistry to measure and analyze Rho proteins expression of normal hepatic cells and hepatoma cells, and hepatoma cells'motility cultured on glass or FN coated surfaces; Application the techniques of immunofluescence to explore the effects of the different adhesion form with FN coated, different contraction state with ML-7 treated and mechanical stretching on the relativity between Rho proteins expression and cytoskeleton assembly in hepatoma cells and normal hepatic cells, it can understand the impact of Rho proteins expression and distribution by cytoskeleton functional status and the relevance between these changes and migration and proliferation in hepatoma cells.Results (1)Hepatoma cells'Rho proteins expression is higher than hepatic cells; Rho proteins expression increased after coating with FN in a low concentration of 1-5μg/ml, decreased after coating FN with 10-20μg/ml;but up-regulated again with FN in a concentration of 40μg/ml;but the level of Rho proteins expression in hepatic cells decreased obviously after coating FN; (2)FN could up-regulate the adhesion rate and growth inhibition rate in hepatoma cells; (3)Upon addition of FN in a low concentration of 2μg/ml, cell motility increased obviously, but high concentration of 20μg/ml cell net displacement and migration path in 1h reduced; (4) With the addition of ML-7(6μM) which inhibit the activity of MLCK, Rho proteins expression weakened in hepatic cells, but had no obvious effect on Rho proteins expression in hepatoma cells; with the high concentration of ML-7(10μM), the cytoskeleton in hepatoma cells disassembled, this influence was not obvious in hepatic cells; cell migration rate and Rho proteins expression reduced; (5)The ratio of cell major axis and minor axis, spherical index and the orientation changed under mechanical stretching; static control group was different; after loading the level of the cytoskeleton assembly and Rho proteins expression increased in hepatoma cells.Conclusion The changes of feedback regulation to Rho proteins expression in hepatoma cells are related to the cytoskeleton structure and function; however, there is a degree of imbalance on the feedback to Rho proteins expression by the different adhesion state in hepatoma cells; Rho protein expression levels and cell motility are positively correlated.