title: The reverse effect of X-ray irradiation on acquired gefitinib resistance in non-small cell lung cancer cell line NCI-H1975 in vitro.
abstract: The clinical efficacy of gefitinib in the treatment of non-small cell lung cancer (NSCLC) with mutations in exon 18, 19 or 21 of epidermal growth factor receptor (EGFR) is limited by the acquired resistance to the drug. To explore whether X-ray irradiation could reverse the acquired gefitinib resistance in NSCLC cell in vitro. We chose a human NSCLC cell line NCI-H1975 to establish acquired gefitinib-resistant cell line named as NCI-H1975/GR. NCI-H1975/GR was irradiated with X-ray and then named as NCI-H1975/GR/XR. In the three cell lines, subsequently cell growth curves and cell population doubling time were calculated by cell proliferation assay, the changes of cell viability were evaluated by trypan blue dye exclusion method and MTT assay, the cell cycle distribution and apoptosis were investigated by flow cytometry, the expressions of E-cadherin and vimentin used to indicate epithelial-mesenchymal transition (EMT) were determined by western blot analysis, the protein expressions in EGFR/KRAS/BRAF transduction pathway were detected by immunocytochemistry, and the mutations of EGFR, KRAS and BRAF were detected by high resolution melting analysis and direct sequencing. We found that the X-ray irradiation enhanced the growth inhibitory effects of gefitinib on the acquired gefitinib-resistant cell line. Of NCI-H1975/GR/XR following gefitinib treatment, the IC50 decreased significantly, the cell proportion of phase G0/G1 was slightly higher, and the apoptosis cell proportion was significantly higher than those of NCI-H1975/GR. In addition, the reversal of EMT being present in NCI-H1975/GR cells was likely appearing in NCI-H1975/GR/XR cells. These results indicated that the acquired gefitinib resistance could be reversed by X-ray irradiation in NSCLC cell line NCI-H1975 harboring both the L858R and T790M mutation in vitro.
authors.affiliation: Dalian Medical University, Dalian, 116044, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Wei
authors.forename: Baoxia
authors.initials: B
authors.lastname: Zhao
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.forename: Weipeng
authors.initials: W
authors.lastname: Lv
authors.forename: Ling
authors.initials: L
authors.lastname: Lv
authors.forename: Bo
authors.initials: B
authors.lastname: Song
authors.forename: Shen
authors.initials: S
authors.lastname: Lv
mesh_terms: D015703:Antigens, CD; D000970:Antineoplastic Agents; D017209:Apoptosis / Q000187:drug effects; D015820:Cadherins / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004252:DNA Mutational Analysis; D019008:Drug Resistance, Neoplasm / Q000528:radiation effects*; D004354:Drug Screening Assays, Antitumor; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D066246:ErbB Receptors / Q000235:genetics; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy; D011518:Proto-Oncogene Proteins / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D011799:Quinazolines / Q000494:pharmacology*; D014746:Vimentin / Q000378:metabolism; D014965:X-Rays; D018631:ras Proteins / Q000235:genetics
chemical_list: D015703:Antigens, CD; D000970:Antineoplastic Agents; C513384:CDH1 protein, human; D015820:Cadherins; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D011799:Quinazolines; D014746:Vimentin; C512478:EGFR protein, human; D066246:ErbB Receptors; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D000077156:Gefitinib