Author of

• 20182

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  P3.03 - Chemotherapy/Targeted Therapy (ID 719)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Chemotherapy/Targeted Therapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 24058

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    P3.03-013 - Identification of Proteasomal Catalytic Subunit PSMA6 as a Therapeutic Target for Lung Cancer through a Pooled shRNA Screen (ID 8867)

    09:30 - 09:30  |  Presenting Author(s): Mitsuo Sato
    • Abstract

    Background:
    Recent advances in high-throughput genetic analysis revealed that single lung cancer cells harbour a number of genetic and epigenetic changes. Nevertheless, findings from cancer epidemiology and the experimental models of the multi-step lung carcinogenic process, which were developed by our group and others, suggested that only a handful of changes are ‘drivers’ whereas others are only ‘passengers’. Thus, it is very important to identify those that truly contribute to the oncogenic properties of cancer cells by performing functional screening. To this end, we performed screening with a pooled shRNA library in search for genes that are critical for the survival and/or proliferation of lung cancer cells using a lung cancer cell line.
    
    Method:
    NCI-H460 cell line was used for semi-genome-wide dropout viability analysis using a pooled shRNA library that targeted 5,043 genes. Two Cdk4/hTERT-immortalised normal human bronchial epithelial cell lines, HBEC3 and HBEC4 were used as controls. Pathway analysis was done using NIH-DAVID. Microarray gene expression analysis was done using Illumina Human WG-6 v3.0 Expression BeadChip for 163 non-small cell lung cancer (NSCLC) cell lines and 59 normal control cell lines. DNA copy number analysis with array CGH was done for 108 NSCLC cell lines. Proteasome activity was measured using a 20S proteasome activity assay kit. 20 pairs of resected lung cancer and matched normal lung samples were used for immunohistochemistry of PSMA6. Cell growth was evaluated by WST-1 colorimetric proliferation assay. Cell cycle analysis was done using FACS for cells stained with propidium iodide.
    
    Result:
    shRNA screening targeting 5,043 genes in NCI-H460 identified 51 genes as candidates for therapeutic targets. Pathway analysis revealed that the 51 genes were enriched for the five pathways, including ribosome, proteasome, RNA polymerase, pyrimidine metabolism and spliceosome pathways. We focused on the proteasome pathway that involved six candidate genes because its activation has been demonstrated in diverse human malignancies, including lung cancer. Microarray expression and array CGH data showed that PSMA6, a proteasomal subunit of a 20S catalytic core complex, was highly expressed in lung cancer cell lines, with recurrent gene amplifications in some cases. Therefore, we further examined the roles of PSMA6 in lung cancer. Silencing of PSMA6 induced apoptosis or G2/M cell cycle arrest in cancer cell lines but not in an immortalised normal lung cell line.
    
    Conclusion:
    Our data suggested that PSMA6 serves as an attractive target with a high therapeutic index for lung cancer.