Background: Embryonic signaling pathways that play an important role during embryo development, later on support the maintenance of adult stem cells and are also found activated in various cancers. The activated embryonic signaling, mainly Hedgehog (HH), WNT and NOTCH, have been shown to be activated in a number of cancers and demonstrated to promote growth, provide survival advantage and resistance to various drugs. The role of these embryonic signaling pathways in the development of lung cancer is not well defined. Identification of particular pathways active in cancer and elucidation of their mechanism of action in cancer development could provide a basis of devising a successful therapeutic intervention.
Objective: Define the role of embryonic signaling pathways in cancer cells.
Methodology: The presence and functional interaction of various embryonic signaling pathways in lung cancer was evaluated using human non-small cell lung carcinoma cell lines (e.g. HOP62, A549, H23, H522) as model system. The signaling pathways were inhibited using specific small molecule inhibitors and shRNAs mediated knockdown of the pathway components. The lentiviruses expressing shRNA were made and used to deliver the shRNA in NSCLC cells. The effect on the target gene expression (quantitative real time RT-PCR and western blotting), cell proliferation (ATP quantitation), cell migration (scratch/wound assay) and anchorage independent growth (soft agar assay), was evaluated. Currently, the activation of pathways in cancer cells of primary lung cancer samples is being evaluated by immunohistochemistry (IHC) and RNA in situ hybridization (ISH).
Preliminary Results and Conclusions: Attenuation of individual embryonic signaling pathways using specific small molecule inhibitors and shRNAs, indicated crosstalk and hierarchy of these pathways in controlling various processes in tested cancer cells. Our results suggest the predominance of HH signaling in non-small cell lung carcinoma. We are in the process of expanding our observation to more cell lines and human cancer samples. Our work will establish the role of embryonic signaling pathways in lung cancer and would further help in establishing a framework for future therapeutic intervention.
Citation Format: Samer Singh, Dao M. Nguyen, Anthony J. Capobianco, David J. Robbins. Role of embryonic signaling pathways in lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1951. doi:10.1158/1538-7445.AM2014-1951