Fig. 1

A The effect of erlotinib at gradient concentrations on CAL-27 and CAL-27ER cells. The viability of CAL-27ER cells was higher at the same concentration, and there was a significant difference between 0.1 μM and 2.5 μM. B The effect of gradient concentrations of erlotinib on HN-6 and HN-6ER cells. The cell viability of HN-6ER cells at the same concentration was higher, and there was a significant difference between 0.1 μM and 2.5 μM. C CAL-27 and HN-6 EGFR-resistant strains showed no significant change in p-EGFR expression under the EGFR inhibitor (erlotinib) at a concentration of 0.5 μM, while that of the wild-type strain significantly decreased. D The migration and invasion abilities of the CAL-27 ER cell line were stronger than those of the wild type, and the number of cells passing through the Transwell chamber at the same time was greater than that of the wild type. (Scale bar: 100 μm). E The migration and invasion abilities of the HN-6 ER cell line were stronger than those of the wild type, and the number of cells passing through the Transwell chamber at the same time was greater than that of the wild type. (Scale bar: 100 μm). F OSCC patients with or without cervical lymph node metastasis and OSCC cell line sequencing and heatmap analysis. G Volcano plot of OSCC patient specimen sequencing data. LCN2 was identified among the highly expressed genes in the metastatic group. H Volcano plot of data from CAL-27 cells and their ER cells. LCN2 was identified among the highly expressed genes in ER cells. I Volcano plot of data from HN-6 and its ER cells. LCN2 was identified among the highly expressed genes in ER cells. J Venn diagram of genes that were upregulated before and after transfer obtained by sequencing OSCC patients and OSCC cell lines; a total of 3 genes were upregulated. K Western blotting of the sequencing results confirmed that LCN2 expression was significantly increased in highly metastatic OSCC cells