The Influence Of Grp78 On The Invasion And Metastasis Of Tongue Cancer Cells And The Related Mechanism

ObjectiveTo explore the role of Grp78 in the invasion and metastasis of human tongue cancer cells and the related molecular mechanisms.Methodspc DNA3.1(+)- Grp78 recombinant plasmid was used to transfect tongue cancer cell line Tca-8113 to establish the cells that stably expressed Grp78(78C6) and western blot method was used to detect the expression of the Grp78 and then si RNA- Grp78 and si RNA-FAK were used to transfect 78C6 in order to knockout the expression of Grp78 and FAK.Cell wound healing assay and Transwell experiment were used to analyze the ability of cell migration and cell invasion.Immunofluorescence and cell stretching experiments were used to detect cytoskeleton arrangement and cell stretch.The GST- pulldown technology was used to analyze the activity of Rac1 and Rho A.Western blot was used to detect the expression of p-FAK,FAK,Rac1 and Rho A.Results1.Overexpression of Grp78 significantly promoted invasion and metastasis of tongue cancer cells compared with the control group and these phenomena could be inhibited by si RNA- Grp78(P < 0.05).2.Overexpression of Grp78 also promoted the adhesion of tongue cancer cells compared with the control group(P < 0.05).3.Cytoskeleton staining results showed that overexpression of Grp78 caused Cytoskeleton microfilament to be mainly distributed in the edge of cell,however this effect could be suppressed by si RNA- Grp78 transfection which leaded to stress fibers appear in cortical areas.4. The activity of Rac1 was higher and Rho A was lower in Tca-8113 / Grp78 cells than the control group while after transfection of si RNA- Grp78 in Tca-8113 / Grp78 cells the activity of Rac1 was lower and Rho A was higher than the control group(P < 0.05),but the expression of Rac1 and Rho A were not be affected by Grp78(P>0.05).5. Overexpression of Grp78 promoted the expression of p-FAK,and knockdown of Grp78 decreased the expression of p-FAK(P < 0.05),but the total expression of FAK was not affected by Grp78(P < 0.05).6. Knockdown of FAK in 78C6 cells decreased the activity of Rac1 and increased the activity of Rho A(P < 0.05),but the expression of Rac1 and Rho A were not be affected by FAK(P>0.05).7. Knockdown of FAK inhibited the ability of adhesion,invasion and metastasis of tongue cancer cells,and also affected the arrangement of Cytoskeleton.Conclusions1.Grp78 is involved in the regulation of the metastasis,invasion,adhesion and arrangement of Cytoskeleton of tongue cancer cells Tca-8113.2.Grp78 promoted invasion and metastasis of tongue cancer cells by medicating the activity of Rac1 and Rho A dependent on the phosphorylation of FAK.