Investigation of the effects and mechanisms in exogenous Rac1 gene expression on HT1080fibrosarcoma cell invasion across collagen barrier / 肿瘤研究与临床

ABSTRACT

Objective To investigate the effects and relevant mechanisms of exogenous Rac1 gene expression on HT1080 fibrosarcoma cell invasion across collagen barrier. Methods HT1080 fibrosarcoma cell lines that stably expressed transfected dominant negative [Rac1V12N17(HN)], constitutively active Rac1 [Rac1V12(HV)] and vector(HW) respectively were used. Structure of actin cytoskeleton was stained with Texas Red-conjugated phalloidin to show the morphological characters of the cells cultured in 3D medium containing collagen protein. Assay of cell invasion across collagen barrier was performed on a thin layer of collagen gel covered the membrane of transwell chamber, and two kinds of protease inhibitor were used to observe their effects on above-mentioned invasive assay. Gelatin substrate zymography were used to detect secreted MMP activity in the medium of cells cultured in 3D matrix. Results HT1080 cells stably expressing Racl mutant exhibited distinct morphological and invasive properties, and the increased invasive ability could be eradicated after using MMP inhibitor. Exogenous Rac1 gene expression on HT1080 fibrosarcoma cell could facilitate the activation of MMP-2 secreted in the medium of either collagen or fibrin 3D cell culture system.Conclusion The stable expression of exogenous Rac1 gene in HT1080 fibrosarcoma cells could induce aggregation of actin fiber and promote invasivc property. The enhancement of MMP-2 activation by exogenous Rac1 gene expression may be one of the relevant mechanisms.