Reconstruction of cytoskeleton filament actin of human mature dendritic cells by transforming growth factor-β1 in a concentration-dependent manner

Abstract:

Objective：To explore the effects of transforming growth factor-β1（TGF-β1） on the cytoskeleton filament actin（F-actin） and expression of some binding proteins in mature dendritic cells（mDCs） in order to further understand the biological behaviors and find the clue of improving the clinical efficiency of DCs-based therapy against cancer. Methods：mDCs were treated with different concentrations of TGF-β1 and the organization of cytoskeleton F-actin and expression of some cytoskeleton-binding proteins were respectively observed and measured by laser confocal microscopy and Western blot. Results：（1）F-actin organization was reconstructed in mDCs treated with various concentrations of TGF-β1 compared with that in control group. F-actin expression quantity in 3 ng/ml group was significantly down-regulated（P=0.000） and expres－sion quantity of F-actin in 5 ng/ml group was significantly up-regulated（P=0.000）. （2）Length of cell membrane protrusions in 3 ng/ml and 5 ng/ml group was thinner and shorter than that in control group（P=0.001，0.000）. Number of cell membrane pro－trusions in 1，3，5 ng/ml groups was sparser than that in control group（P=0.000）. Non-liner correlation between expression of F-actin and characteristics of cell membrane protrusion（length and number） was observed（R2=0.828，0.746 respectively，P=0.000）. （3）Expression of cytoskeleton-binding proteins and expression quantity of F-actin in all groups was significantly down-regulated（P=0.001，0.000）. Phosphorylation of cofilin1 in 1 ng/ml and 3 ng/ml group was significantly down-regulated（P=0.000，0.000）. Expression quantity of profilin in 1，3，5 ng/ml group was significantly up-regulated（P=0.001，0.001，0.013）. Conclusions：Organization of cytoskeleton F-actin and some of its binding proteins in mDCs are affected by TGF-β1 in a concentration-dependent manner，indicating that the signal pathway of TGF-β1 should be blocked in appropriate way before performing DCs-based im－munotherapy against cancer. It’s of great significance to understand the biological behaviors and immune escape mechanism of tumor.