Activated O2(•−) and H2O2 mediated cell survival in SU11274-treated non-small-cell lung cancer A549 cells via c-Met-PI3K-Akt and c-Met-Grb2/SOS-Ras-p38 pathways.

The pharmacological activity of SU11274 is primarily due to its inhibition of hepotocyte growth factor receptor (c-Met) kinase overexpression. In this study, we demonstrated that the pathway involved in SU11274-induced autophagy was presumably through inhibition of c-Met and its down-stream pathways, including phosphatidylinositol 3-kinases – Akt (PI3K–Akt) and the growth factor receptor bound protein-2 / son of sevenless – Ras – p38 MAPK (Grb2/SOS–Ras–p38) pathway. SU11274 time-dependently induced the generation of superoxide anion (O2(•−)) and hydrogen peroxide (H2O2). There is a negative feedback loop between reactive oxygen species (ROS) induction and SU11274. Then, we investigated the role of ROS in protecting cells against SU11274-induced autophagic cell death in A549 cells. O2(•−) and H2O2 generation activated c-Met–PI3K–Akt and c-Met–Grb2/SOS–Ras–p38 signaling pathways, which were suppressed by O2(•−) scavenger superoxide dismutase (SOD) and H2O2 scavenger catalase. In conclusion, O2(•−) and H2O2 evoked cell resistance to SU11274 via activating c-Met–PI3K–Akt and c-Met–Grb2/SOS–Ras–p38 pathways in A549 cells. SU11274 also induced ROS generation in Caenorhabditis elegans.