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. 2014 Apr 30;9(4):e95884. doi: 10.1371/journal.pone.0095884

Figure 4. Metformin inhibits IL-6 promotion of lung carcinoma cell invasion and EMT in vitro.

Figure 4

(A) Invasion of IL-6 treated lung cancer cells in the presence of various concentrations of metformin. The selective STAT3 inhibitor cucurbitacin Q (Cuc, 2 µmol/L) served as a positive control for inhibition of lung cancer cell invasion. (B) Protein expression levels of E-cadherin, vimentin and snail in cells treated with IL-6 alone or in combination with metformin were analyzed by western blotting. β-actin was used as a loading control. (C) mRNA expression levels of E-cadherin, vimentin and snail in cells treated with IL-6 alone or in combination with metformin were examined by real time PCR and normalized by GAPDH. (D) The expression of E-cadherin and vimentin was detected by immunofluorescence in A549 and HCC827 cells treated with IL-6 alone or in combination with metformin (800×). Error bars represent the standard deviation (*, p<0.05; **, p<0.005).