Abstract

Lung cancer continues to be the leading cause of cancer-associated mortality worldwide, with approximately 85% of lung cancer patients diagnosed with non-small cell lung cancer (NSCLC). Despite significant advancement in diagnostic and therapeutic approaches, the 5-year overall survival rate of patients remains lows at only ~20-25%. To date lung cancer research has primarily focused on the deregulation of protein-coding genes to identify oncogenes and tumor suppressors as potential diagnostic markers and therapeutic targets underrepresenting the emerging role of long non-coding RNAs (lncRNAs). LncRNAs are longer than 200 base pairs, lack coding potential, transcribed by RNA polymerase II, spliced (like mRNAs), 5’ capped, and polyadenylated. Of the thousands of discovered lncRNAs, only a small subset has been well characterized in lung cancer, highlighting our limited understanding of how lncRNA regulatory mechanisms contribute to lung cancer biology. To address this critical knowledge gap, this dissertation seeks to advance our understanding of a lncRNA-dependent regulation of a critical transcription factor, NRF2, to confer NRF2-dependent oncogenic progression in NRF2/KEAP1 mutant NSCLC patients. In this dissertation, we focused on a lung cancer associated lncRNA, referred to as RNA Associated with MetastasiS 11 (or RAMS11) as it is broadly oncogenic across cancer types and involved in metastatic progression. To explore potential associations, we employed a pan-cancer mutational analysis to determine whether elevated RAMS11 expression is associated with mutations in commonly altered oncogenic pathways. Notably, we found that RAMS11 expression was elevated in patients harboring either NRF2 or KEAP1, with the two mutations being generally mutually exclusive (i.e., tumors carried a mutation in one gene but not both), in both LUAD and LUSC. Concurrently, we knocked down RAMS11 in cellular models of NSCLC to assess the effect on classical oncogenic phenotypes and found significant alteration in cell viability, tumorigenesis and metastasis. These data highlight the role of RAMS11 in NSCLC oncogenesis and progression. Mechanistically, persistent NRF2 (NRF2-activating and KEAP1-inactivation mutations) transcriptionally activates RAMS11, which in turn binds to NRF2 protein and GSK3B to block NRF2 degradation, forming a positive feedback loop that promotes NRF2 stability and oncogenic activity. To explore additional regulatory functions of RAMS11, we focused on its regulation of cancer-specific, clinically actionable targets. To this end, we performed integrative analysis to determine how changes in NRF2 stability impacts its genome-wide chromatin occupancy and associated transcriptional responses of downstream target genes. We uncovered NOTCH3, a known NRF2 cancer-specific, non-canonical target. Our findings mechanistically revealed RAMS11 mediates NRF2 occupancy at the NOTCH3 enhancer, where it transcriptionally regulates NOTCH3 expression, driving cell proliferation, tumor-initiating activity and chemoresistance in NSCLC cells. Given that NRF2-driven transcriptional programs and NOTCH3 signaling have both been implicated in promoting tumor survival under therapeutic stress, we next examined whether RAMS11 influences chemoresistance. We discovered that RAMS11 regulates chemotherapy resistance by modulating chemotherapy-induced cell death. In summary, we provided mechanistic insight into RAMS11-dependent NRF2 transcriptional regulation in lung cancer disease progression. Understanding how NRF2/KEAP1 mutations in NSCLC patients activate canonical and cancer-specific, non-canonical target genes represents a critical knowledge gap. In the long-term this research has the potential to translate into novel strategies for restoring normal NRF2 tumor-suppressive function to manage treatment for a large fraction of NSCLC patients.

Committee Chair

Christopher Maher

Committee Members

Brett Herzog; Jason Weber; John Edwards; Malachi Griffith

Degree

Doctor of Philosophy (PhD)

Author's Department

Biology & Biomedical Sciences (Molecular Genetics & Genomics)

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

8-7-2026

Language

English (en)

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Available for download on Sunday, August 06, 2028

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