Abstract 1941: TRAIL-induced kinase activation in Non small cell lung cancer cells

Abstract

Abstract Non-small cell lung cancer (NSCLC) is a disease with poor prognosis and novel therapeutic approaches are greatly needed. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is an interesting agent that is able to trigger apoptosis through interactions with TRAIL receptors. An important feature of TRAIL is its ability to induce apoptosis in a wide variety of tumors without harming normal cells, making it an attractive anti-cancer therapeutic compared to conventional anti-cancer agents. However, TRAIL is also able to activate signaling pathways that are involved in survival, proliferation and migration of tumor cells. Thus, TRAIL-based therapies combined with inhibitors of such pathways are expected to enhance therapeutic benefit. In this study, we aimed to identify and characterize kinases that are activated by recombinant TRAIL in NSCLC cells. We monitored the activation of a number of kinases known to be involved in TRAIL signaling by Western blotting, including p38 MAPK, JNK, ERK and Akt. In addition we employed PepChip kinase arrays. With these arrays 1024 peptide kinase substrates can be screened in one experiment, whereby a comparison of kinase patterns between untreated and treated cells can be obtained. NSCLC, H460 and A549 cell lines, which are sensitive and resistant for TRAIL, respectively, were exposed to 50 ng/ml TRAIL for different periods of time (5 to 240 minutes) to evaluate the kinetics of kinase activation. In H460 cells, TRAIL induced the phosphorylation of p38 MAPK after 2 hours and JNK1/2 after 3 hours. As the activation of these kinases can be both anti- and pro-apoptotic, kinase inhibitors were used to explore this further. In H460 cells the activation of JNK, ERK and Akt had anti-apoptotic activity. Inhibition of these kinases with SP600125, PD098059, and LY294002, respectively, showed a 2-fold increase in apoptosis when combined with TRAIL. The activation of MAPK p38 on the other hand was pro-apoptotic, since its inhibition with SB203580 resulted in a reduction of TRAIL-induced apoptosis in H460 cells. In resistant A549 cells, however, Akt, ERK, p38 MAPK, and JNK1/2 activation appeared to have anti-apoptotic activity. Furthermore, in these cells an increase in IκBα phosphorylation was observed that was not seen in H460 cells, where levels of phosphorylated IκBα decreased after 1 hour that correlated with cleavage of RIP. Thus suppression of NFκB activation could be associated with TRAIL sensitivity. PepChip kinase arrays, revealed the activation of kinases that are involved in cell migration, such as Rho/Rock in A549 cells, and further investigations are ongoing. In conclusion, we observed differential TRAIL-dependent activation of p38 MAPK, JNK1/2, ERK, Akt and IκBα in sensitive and resistant NSCLC cells as well as in pathways that regulate migration. The relationship with TRAIL antitumor activity is currently further explored. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1941. doi:10.1158/1538-7445.AM2011-1941