CD74-ROS1 G2032R mutation transcriptionally up-regulates Twist1 in non-small cell lung cancer cells leading to increased migration, invasion, and resistance to crizotinib.

The c-ros oncogene 1 (ROS1) is a receptor tyrosine kinase, which has been identified as an oncogene driver of non-small-cell lung cancer (NSCLC). Although crizotinib has a prominent effect on ROS1, resistance is inevitable. Development of the acquired ROS1 G2032R mutation has been reported as a resistant mechanism to ROS1 inhibitors in ROS1-rearranged (ROS1+) NSCLC patients. To explore the mechanism of drug resistance, we constructed the crizotinib resistance cell line, A549-CD74-ROS1 G2032R mutation cells, by the methods of fusion polymerase chain reaction (PCR), plasmid construction and cell transfection in vitro. The results showed that the expression of CD74-ROS1 or CD74-ROS1 G2032R mutation in A549 cells induced epithelial-mesenchymal transition (EMT), dramatically enhanced the ability of invasion and migration, and increased expression of matrix metalloproteinase (MMP)-9 and Twist1 transcription factor. Moreover, we found that inhibition of Twist1 could reverse EMT induced by CD74-ROS1 G2032R mutation. Combination of Twist1 siRNA and crizotinib significantly reduced cell vitality, inhibited cell invasion and migration, and promoted apoptosis in A549-CD74-ROS1 G2032R mutation cells. Taken together, these results suggested that CD74-ROS1 G2032R mutation mediated EMT phenotype by increasing the expression of Twist1, resulting in drug resistance. Combination of Twist1 silence and ROS1 inhibitor may provide a potent strategy to treat the ROS1+ NSCLC patients with crizotinib resistance.