Figure 1

HMGA1 overexpression is related to resistance to Cetuximab and 5-Fluorouracil in GEO colon carcinoma cells. (A) Western blot analysis of protein extracts from GEO and GEO CR (Cetuximab Resistant) cells, using HMGA1 and β-actin antibodies. β-Actin was used as loading control (Left Panel). qRT-PCR analysis of HMGA1 mRNA in GEO and GEO CR cells. Relative expression values indicate the relative change in HMGA1 mRNA expression levels between GEO and GEO CR, normalized with β-actin. The error bars represent the mean ± S.D. of three independent experiments performed in triplicate (Right Panel). (B) Dose response curve for GEO and GEO CR cells treated with cetuximab (Left Panel) or 5-fluorouracil (Right Panel). Cells were exposed to the indicated doses of drugs and, after 72 h, absorbance at 490 nm was measured using a microplate reader to evaluate cell viability. The results are expressed as percent relative to the control. Values are the mean ± S.D. of three experiments performed in triplicate. Dose response curves were obtained by non-linear curve fitting using GraphPad Prism 5.0. program. Note that the concentration is shown as logarithmic function. *p < 0.05 significance level compared with GEO cells. (C) IC50, inhibitory concentration that kills 50% of cell population and Resistance index calculated as IC50 GEO CR/IC50 GEO cell line.