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  P3.01 - Poster Session 3 - Cancer Biology (ID 147)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Biology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

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    P3.01-006 - Discovery of new membrane-associated proteins preferentially expressed in small-cell lung cancer (ID 2306)

    09:30 - 09:30  |  Author(s): B. Detry
    • Abstract

    Background
    Small-cell lung cancer (SCLC) is the most aggressive subtype of lung cancers, with no early detection strategy or targeted therapy currently available. We hypothesized that difference gel electrophoresis (DIGE) may allow the identification of membrane-associated proteins specific to SCLC, the advancement of our understanding of SCLC biology, and the discovery of new candidate diagnostic or therapeutic biomarkers.

    Methods
    Membrane-associated protein lysates were prepared in quadruplicate from three SCLC, three non-small-cell lung cancer (NSCLC), and three immortalized normal bronchial epithelial cell lines. The 36 samples were co-analyzed by DIGE and subsequent protein identification was performed by mass spectrometry (MS). Identified proteins were submitted to Ingenuity pathway analysis (IPA). Candidate biomarkers were validated by Western blotting (WB) and immunohistochemistry (IHC), and tested against clinical outcomes.

    Results
    Principle component analysis on the global DIGE dataset demonstrated that the four replicates derived from each of the nine cell lines clustered very closely from one another, as did samples within the same histological group. A total of 135 distinct protein features were differentially expressed in SCLC as compared with NSCLC and bronchial airway epithelial cell lines (P<0.001). Those included 137 different proteins identified by tandem MS. IPA revealed that these proteins were overrepresented in the cellular assembly, organization, morphology, and tissue morphology networks. DPYL2, GNAQ, RSSA, RUVB1, and STMN1 were found to be the most discriminatory candidate biomarkers among the membrane-associated proteins overexpressed in SCLC as compared with NSCLC and normal bronchial airway cell lines. Overexpression of DPYL2, GNAQ, and STMN1 was verified in SCLC cell lines by WB. Intense protein expression of DPYL2, GNAQ, RUVB1, and STMN1 was also confirmed in SCLC by IHC on tissue microarrays (TMA). These proteins’ expression levels measured by IHC were significantly associated with the SCLC subtype and survival in a univariable analysis but could not be verified as independent in a multivariable analysis.

    Conclusion
    Proteomic analysis of membrane-associated proteins in lung cancer and bronchial airway epithelial cell lines revealed 137 proteins differentially expressed in SCLC. These proteins were enriched for cellular assembly, organization, morphology, and tissue morphology networks. Of the five proteins selected for clinical validation, DPYL2, GNAQ, RUVB1, and STMN1 overexpression in SCLC was verified by WB and IHC, suggesting that these results need to be tested for functional implication in SCLC progression. The association with survival requires further validation in a larger clinical dataset. Funding This work was supported by a VA Merit review award 1I01CX000242 to PPM. SO was supported by a Télévie Grant, a Fondation Mont-Godinne Grant and a Clinician-Researcher Mandate from Secteurs des Sciences de la Santé, Université Catholique de Louvain (UCL), Belgium.