Oncogenic GOPC-ROS1 fusion promotes the formation of lymphatic malformations by impairing tight junction and its crizotinib resistance through repressing ferroptosis.

The complicacy of genetic abnormalities in lymphatic malformations (LMs) limits their treatment in clinical practice. In this study, we identified a complex LM with Golgi-associated PDZ and coiled-coil motif containing (GOPC)-proto-oncogene ROS 1 (ROS1) fusion that responds to crizotinib. The oncogenic roles of GOPC-ROS1 fusion in the formation of LMs remain unknown. This study showed that GOPC-ROS1 fusion promotes the proliferation, migration, and invasion of human lymphatic endothelial cells (HLECs). Moreover, fusion of GOPC and ROS1 enhances the catalytic activity of the ROS1 fragment as a receptor tyrosine kinase and alters the profiling of tyrosine phosphorylation in HLECs. Multiple novel tyrosine sites phosphorylated by GOPC-ROS1 in HLECs were validated. Impaired phosphorylation of ZO-1 protein at tyrosine 895, resulting from decreased co-location of GOPC-ROS1 and ZO-1 proteins, inhibits the tight junction of HLECs, which is important for the formation of functional lymphatic vessels. We next investigated the potential mechanisms of crizotinib resistance in GOPC-ROS1 CLM. It was found that high glycolysis and low ferroptosis levels, which are dependent on ENO1-phosY44, contribute to the crizotinib resistance of GOPC-ROS1 HLECs. Targeting ferroptosis by inhibiting System Xc- using sulfasalazine (SASP) represses the crizotinib resistance of GOPC-ROS1 HLECs. A combination of SASP and crizotinib may be a potential therapeutic strategy for various GOPC-ROS1 tumours.