UC Santa Cruz

U2AF1S34F, a somatic splicing factor mutation, is frequently recurrent in human neoplasias such as lung adenocarcinoma (ADC). Although U2AF1S34F has been shown to occur early in tumor lineages, the mutation, alone, is insufficient for producing tumors. However, lung ADC patients with U2AF1S34F frequently have co-occurring KRAS mutations and smoking histories. We hypothesized that U2AF1S34F interacts with oncogenic KRAS and environmental stress to promote tumor-forming potential. To elucidate interaction of U2AF1S34F with a co-occurring mutation, we generated human bronchial epithelial cells (HBEC3kts) with U2AF1S34F or with co-occurring U2AF1S34F and KRASG12V. From analyzing short-read transcriptome sequences, we found synergistic effects of co-occurring mutations on gene expression in cell cycle and inflammatory pathways associated with increased tumors in mouse xenografts, anchorage-independent growth, proliferation, and altered cytokine production.nterestingly, HBEC3kts harboring only U2AF1S34F display increased splicing in stress granule protein genesand increased viability in cigarette smoke concentrate. Our results suggest that U2AF1S34F may prime cells for transformation by allowing precancerous cells to survive longer when environmental stress is present, permitting U2AF1S34F cells to accumulate transforming mutations, such as KRASG12V.

Next, I sought to further investigate the impact of U2AF1S34F and environmental stress response by profiling the mRNA modification landscape of U2AF1S34F and U2AF1WT HBEC3kts exposed to cigarette smoke concentrate (CSC) using Nanopore direct RNA sequencing (dRNA-seq). Preliminary results show that RNA modificatios in autophagy gene VAMP8 were associated with altered protein expression levels. We also show that CSC and the presence of U2AF1S34F both increase the number of RNA modifications in the transcriptome, with the highest number of modifications occurring in CSC treated U2AF1S34F HBEC3kts. We hypothesize that U2AF1S34F and CSC modify the RNA modification landscape in a synergistic way to increase oncogenic potential.