Abstract 3019: TGFβ3 is a less potent inducer of TGFβ signaling than TGFβ1 in non-small cell lung cancer cells

Transforming growth factor beta (TGFβ) is an essential cytokine for tissue homeostasis. Its signalling pathway is under intense study as it is commonly dysregulated in many cancers, including pancreatic cancer, non-small cell lung cancer, and colorectal cancer. The TGFβ signalling cascade is propagated by the binding of ligand to cell-surface serine-threonine kinase receptors, which leads to the phosphorylation of receptor regulated Smad (R-Smad) proteins. There are three main ligands capable of activating the classical TGFβ pathway: TGFβ1, TGFβ2 and TGFβ3. These ligands show distinct spatial and temporal expression patterns and have non-overlapping functions in vivo. Extensive studies have been conducted on the role of TGFβ1 in the tumour microenvironment, and the role of TGFβ3 has largely been thought to be the same as TGFβ1 though there are few studies to support this claim. Interestingly in the wound microenvironment, TGFβ1 and TGFβ3 have vastly different signalling outcomes: TGFβ1 promotes the formation of a scar while TGFβ3 induces scar-free wound resolution. The objective of the present study was to evaluate the signalling capacity of TGFβ1 and TGFβ3 in non-small cell lung cancer cells. Our studies show that TGFβ3 is less potent at initiating Smad2 phosphorylation than TGFβ1, resulting in reduced transcriptional activity, as assessed by microarray analysis. We also observed that TGFβ3 is less effective than TGFβ1 at altering cell-cell adhesions. In order to assess the differences in signalling potential, we investigated TGFβ receptor engagement at the cell surface using radiolabelled TGFβ ligands. We observed that the ratio of activated receptors in signalling complexes is altered in the presence of TGFβ3, which may lead to a decreased signalling capacity. Future studies will evaluate the capacity of TGFβ3 to induce cancer cell migration and invasion. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3019. doi:1538-7445.AM2012-3019