Fig. 3: Identification of NRAS gene amplification by CGH and sensitivity to NRAS knockdown combined with EGFR inhibition.
From: Evolution of MET and NRAS gene amplification as acquired resistance mechanisms in EGFR mutant NSCLC
a NRAS and MET amplification identified by CGH. CUTO44 genomic DNA was analyzed by CGH using Illumina CytoSNP-850K bead array. Images show chromosomes 1 and 7, highlighting the regions containing NRAS and MET. b NRAS protein expression in EGFR mutant lung cancer cell lines. Western blot showing NRAS protein levels in EGFR mutant lung cancer cell lines. Representative images are shown. c NRAS FISH on the patient biopsy after progression on erlotinib (left) and in the CUTO44 cell line (right) with NRAS probe in green and chromosome 1 centromere probes in red. d Protein expression changes following NRAS knockdown by siRNA. CUTO44 cells were transfected with 50 nM NRAS siRNA for 48 h, then treated with the indicated drug combinations for 2 h prior to lysis for western blot analysis of protein expression. Representative images, n = 2. e Cell viability following NRAS knockdown. CUTO44 cells were transfected with NRAS siRNA for 48 h prior to being treated with the indicated concentration of drugs for 72 h and viability was measured by MTS assay. Showing the mean ± SD, n = 3 biological replicates.
