Cancer is driven by a complex network of genes and pathways. Decades of research have discovered various oncogenes and tumor suppressors that can drive cell transformation and malignancy. However, there are many genes that are essential for cancer cell survival, but are not mutated themselves. These ?non- oncogenes? can be involved in various cell-survival pathways such as the stress response, and might explain some of the heterogeneity observed among tumor cells that have the same driver mutations. How can we identify and target these genes to offer alternative routes to disarm and sensitize cancer cells to therapeutic interventions? One way to identify ?non-oncogene? pathways is to evaluate how proliferating cells adjust to variable and evolving environments. By examining heterogeneous transcriptional regulatory states of single cells in a 3D culture model of breast epithelial organization, our lab discovered an important regulatory pathway that had a common upstream regulator, NRF2. NRF2 is a known oncogene in lung cancer, but mutations in the transcription factor are uncommon in breast cancer. In this proposal, I am studying the role of the non- oncogene, NRF2, in an aggressive subtype of breast cancer, in the hopes of determining new strategies to disrupt this non-oncogene addiction. This project entails three interrelated aims: 1) to determine the functional importance of NRF2 for growth, organization, and survival of triple-negative breast cancer cells; 2) to quantify and model the broader network context of NRF2 dynamics; 3) to test the impact of NRF2 on breast tumorigenesis in vivo.
These aims are focused on the non-oncogene NRF2, which is classically known as an antioxidant transcription factor. Most cancer-related studies of NRF2 have focused on mutations in the transcription factor and the pathway associated with it. Our hypothesis is that there is another layer of NRF2- driven tumorigenesis that occurs on the single-cell level without mutation. A detailed understanding of NRF2 regulation could enable new strategies to disrupt this non-oncogene addiction and re-sensitize cancer cells to their environment and to chemotherapy.
Non-oncogene addiction may explain some of the heterogeneity observed among tumor cells that have the same driver mutations. NRF2 could enable a dynamic, stress responsive pathway that allows breast cancer cells to survive in harsh environments and withstand existing chemotherapies. A detailed understanding of NRF2 regulation could enable new strategies to disrupt this non-oncogene addiction and re-sensitize cancer cells to their environment and to chemotherapy.
