Regulation of Foxp3 expression by TLR4 in Lewis lung cancer cells

Objective:To investigate whether the expression of Foxp3 in Lewis lung cancer(LLC)cells could be regulated by TLR4 activation.Methods:Lipopolysaccharide(LPS) was employed as exogenous ligands to activate TLR4.The mRNA level of Foxp3 was detected by RT-PCR at different time points(12,24,36,48 h)upon LPS stimulation(0,1,10 μg/ml).The protein level of Foxp3 and TLR4 was detected by FCM at 24 h time point upon 10 μg/ml LPS stimulation.Foxp3 mRNA and protein were detected by RT-PCR and FCM respectively after LPS activation following blockade of TLR4 by anti-TLR4/MD2 antibody.Results:The mRNA level of Foxp3 was significantly increased by 10 μg/ml LPS stimulation at 24 hours(P 0.05).The protein level of Foxp3 and TLR4 were significantly up-regulated at 24 h time point upon 10 μg/ml LPS stimulation(P 0.05).The expression of Foxp3 protein was significantly decreased in LLC cells with TLR4 blockade followed by LPS stimulation than that of without TLR4 blocking ones(P 0.05).Conclusion:These results indicate that TLR4 could be involved in the regulation of Foxp3 expression in LLC cells and TLR4 might be the upstream signaling molecules of Foxp3.