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R. Yamashita

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    P1.02 - Poster Session 1 - Novel Cancer Genes and Pathways (ID 144)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P1.02-010 - Evaluation of the oncogenic ability of EML4-ALK to transform human bronchial epithelial cells (HBECs) (ID 1503)

      09:30 - 16:30  |  Author(s): R. Yamashita

      • Abstract

      Lung cancer is a highly lethal disease, and is believed to develop through a multistep carcinogenic process, which involves numerous genetic and epigenetic alterations. Among these alterations, mutations in “driver genes” such as KRAS and EGFR are found in non-small cell lung cancer (NSCLC) and they are demonstrated to contribute to a phenomenon, oncogene addiction. Recently, the EML4-ALK (echinoderm microtubule-associated protein–like 4 anaplastic lymphoma kinase) fusion gene has been discovered as a novel driver gene in a subset of NSCLC. We evaluated the oncogenic transformation ability of EML4-ALK by using an hTERT/CDK4-immortalized normal human bronchial epithelial cell (HBEC) model.

      We used two HBEC lines, HBEC3 and HBEC4. Mutant KRAS[V12]-expressing HBEC was used as a positive control for oncogenic transformation. A lentiviral vector system was used to generate HBECs stably expressing EML4-ALK. EML4-ALK protein expression was confirmed by westernblotting, and downstream pathways were analyzed by westernblotting with phospho-specific antibodies. Malignant phenotypes of EML4-ALK-expressing HBECs were examined by WST-1 proliferation assay and liquid and soft agar colony formation assays.

      Westernblotting analysis showed that EML4-ALK was expressed in HBECs. Analysis of downstream pathways did not show significant differences between EML4-ALK-expressing and control HBECs. Introduction of EML4-ALK in HBECs increased the number of soft agar colonies but its effect was not as strong as KRAS[V12].Figure 1 A. Soft agar colony formation assay showing that EML4-ALK increased the number of colonies compared to control cells to a lesser extent than did KRAS[V12]. B. Cell proliferation assay (MTS-1) showing no significant difference between EML4-ALK-expressing and control HBECs.

      EML4-ALK alone did not induce dramatic oncogenic changes in HBECs. To acquire more malignant phenotype, additional genomic alterations may be required and this is now under investigation.