Figure 1.

NGAL is increased in erlotinib-resistant cell lines. A: LCN2 gene expression analysis by microarray in H441 cells: P-parental cells, E-cells with acquired erlotinib resistance. B: NGAL protein levels are elevated in H358 and H441 cells with acquired resistance to erlotinib (E) compared to the respective parental cells (P) by Western blot. C: The same cells were cultured for 48 hours and secreted NGAL protein levels were assessed by ELISA. NGAL protein levels were significantly higher in erlotinib-resistant cells than in the parental cells (*p = 0.03, **p = 0.02). Error bars indicate standard deviation (SD). NGAL concentration was normalized by total protein concentration.