Author of

• 13580

  +

  P1.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 233)

  • Event: WCLC 2015
  • Type: Poster
  • Track: Biology, Pathology, and Molecular Testing
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)

  • 13582

    +

    P1.04-002 - Protein Signaling Analysis of KRAS Mutant Lung Adenocarcionomas Reveals Variable MAPK and mTOR Pathway Activation (ID 2280)

    09:30 - 17:00  |  Author(s): F.R. Tofanetti
    • Abstract

    Background:
    Despite the numerous efforts made to target KRAS directly, this protein is still undruggable. A number of therapeutics that target linked KRAS pathway members have been tested, but their efficacy in KRAS mutant lung adenocarcinoma is still controversial. Understanding the biochemically linked protein signaling network associated with a KRAS mutation may lead to the identification of therapeutic targets to identify patients that may benefit from a therapeutic agent targeting KRAS downstream substrates.
    
    Methods:
    Thirty-four archived samples from surgically-treated KRAS mutant adenocarcinomas were included in this study. Samples were collected at the H.Lee Moffitt Cancer Center & Research Institute (Tampa, FL) and at the Santa Maria della Misericordia Hospital (Perugia, Italy). Pure cancer epithelial cell subpopulations were isolated using Laser Capture Microdissection. The expression/activation level of 155 proteins was then measured by Reverse Phase Protein Microarray, a high-throughput semi-quantitative platform.
    
    Results:
    The protein activation level of ERK (as measured by phosphorylation of T202/Y204), a direct downstream substrate of KRAS activity, was highly variable across KRAS mutant samples. While a subgroup of patients showed, as expected, high activation of ERK, approximately 2/3 of the patients had a comparable ERK activation level to the wild-type counterpart previously analyzed. The activation level of the remaining protein signaling analytes was then compared between samples with high and low ERK activation. Tumors with high levels of ERK activation showed a significant increase in the signaling network of: 1) the MAPK proliferative pathway including Ras-GRF1 S916, Mek 1/2 S217/221, MSK1 S360, p38MAPKinase T180/Y182 (p=0.03, p<0.01, p=0.04, p<0.01 respectively), 2) the AKT-mTOR pathway including Akt S473, AMPKα1 S485, ATP Citrate Lyase S454, LKB1 S428, mTOR S2448, p70S6K T389, p70S6K T412, 4E-BP1 S65 (p<0.01, p<0.01, p<0.01, p<0.01, p<0.01, p<0.01, p=0.02, p=0.03 respectively).
    
    Conclusion:
    This analysis suggests that the signaling network of KRAS mutant lung adenocarcinomas, while manifesting expected ERK activation as a group, is highly variable. In fact a majority of KRAS mutant tumors had the same range of MEK-ERK activation as KRAS WT tumors. Analysis of high and low ERK activation in the KRAS mutant tumors revealed druggable protein signaling activation of a number of important targets. If validated in a larger study set, these data may have important clinical implication for the allocation of patients toward more effective and specific targeted treatments.