Enhanced cohesion promotes chromosome stability and limits acquired drug resistance in non small cell lung cancer

Chromosome instability, or CIN, defined as a high frequency of whole chromosome gains and losses, is prevalent in many solid tumors. CIN has been shown to promote intra-tumor heterogeneity and correspond with tumor aggressiveness, drug resistance and tumor relapse. However, whether CIN promotes the acquisition of genomic changes responsible for drug resistance remain unclear. Here we assess the role of CIN in the acquisition of drug resistance in non small cell lung cancer. We show that impairment of centromeric cohesion underlies the generation of whole chromosome segregation errors and CIN in non small cell lung cancer cells. Further, we demonstrate that centromere-specific enhancement of chromosome cohesion strongly suppresses CIN and reduces intra-tumor heterogeneity. We demonstrate that suppression of CIN has no impact on NSCLC cell proliferation in vitro nor in tumor initiation in mouse xenograft models. However, suppression of CIN alters the timing and molecular mechanism that drive acquired drug resistance. These findings suggest mechanisms to suppress CIN may serve as effective co-therapies to limit tumor evolution and sustain drug response.