TRAIL and kinases in resistant NSCLC
TRAIL activates kinases involved in cell migration and invasion in resistant NSCLC cells
K Azijli (1), S Yuvaraaj (4), MP Peppelenbosch (3), H Dekker (1), J Joore (2), GJ Peters (1), S de Jong (3) and FAE Kruyt (4).
1Dept. Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands; 2Pepscan Systems B.V., Lelystad, The Netherlands; 3Dept. of Gastroenterology and Hepatology, Erasmus MC-University Medical Center Rotterdam; 4Dept. Medical Oncology, University Medical Center Groningen, University of Groningen, The Netherlands
Grant: Top Institute Pharma
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) belongs to the TNF gene superfamily and it mediates its apoptotic function through interaction to the death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5). 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, in addition to its apoptosis inducing potential, TRAIL is also able to activate signaling pathways that are implicated in cell survival and cell proliferation, counteracting its death-inducing effects. Thus, TRAIL-based therapies combined with inhibitors of pro-survival signals are expected to have beneficial therapeutic effects.
In this study, we set out to examine pro-survival signaling induced by recombinant TRAIL in NSCLC cells. For this we monitored the activation of a number of kinases by using PepChip kinase arrays. With these arrays 1024 peptide kinase substrate 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 15 minutes. In H460 cells, the cells died rapidly whereby the kinase profiling was difficult to monitor. In the resistant A549 cell line on the other hand, TRAIL activated the PI3K/Akt, MAPK, Rho/ROCK and the src/FAK pathways. Whereas the activation of these pathways can cause cell migration, we studied the effect of TRAIL in a wound healing assay and a Boyden Chamber assay. TRAIL was able to close the wound much more compared to the control, indicating cell migration. In the Boyden Chamber assay, the A549 cells invaded much more through the pores after TRAIL incubation. To determine which pathways are involved in this migration, specific kinase inhibitors were used to block the concerned pathways. Inhibition of src with PP2, inhibition of ERK with PD98059 and the inhibition of ROCK witch Y27632 prevented the migrating effect of TRAIL in A549 cells, suggesting that these pathways are involved in the cell migration. Our data showed that in TRAIL-resistant cells, TRAIL does not induce apoptosis, but causes cell migration. This suggests that in clinical setting metastases could occur in cancer patients who are resistant to TRAIL-induced apoptosis. This could worsen their situation. Therefore, it is very important to select patients before TRAIL-therapy for the treatment of cancer, bringing us to 'personalized medicine'.