Fig. 4

A After LCN2 was downregulated in OSCC ER cells, the expression levels of p-EGFR, p-MEK, and p-ERK were also significantly downregulated. In contrast, when LCN2 was upregulated in OSCC cells, the expression levels of p-EGFR, p-MEK, and p-ERK were upregulated. B LCN2 downregulation had no significant effect on EGFR mRNA expression. C LCN2 upregulation had no significant effect on EGFR mRNA expression. D The mRNA expression of EGFR was successfully downregulated by siEGFR in OSCC cell lines. E Inhibition of EGFR expression had no significant effect on LCN2 mRNA expression. F Western blot detection confirmed that EGFR was successfully inhibited but had no significant effect on LCN2 protein expression. G Construction of stably transfected CAL-27 cells labeling LCN2 with the SFB tag and verification by immunoblotting. H Protein silver staining results after co-IP. EGFR is indicated in the red frame. I Mutual co-IP and immunoblotting detection confirmed the interaction between EGFR and LCN2