Investigating the role of NRAS mutations and the implications of co-occurring mutations in acute myeloid leukaemia

Abstract

NRAS mutations occur in 15 % of AML patients and can significantly impact disease progression, particularly when co-occurring with other driver mutations. This thesis investigated the clinical and transcriptional differences associated with NRAS mutations using three publicly available patient datasets: UKNCRI (n = 2113), AML SG (n = 1540), Beat AML (n = 647).

Across cohorts, NRAS wild type patients were significantly older than NRAS mutant patients in the AML SG (p = 0.0020) and Beat AML (p = 0.0376) datasets. No significant differences in overall survival (OS) were observed between NRAS mutant and wild type patients across all three cohorts. Transcriptomic analysis revealed gene dysregulation in NRAS mutant patients, with upregulation of PLDB1, MSLN, QPCT and downregulation of multiple HOXA genes. This suggests a divergent transcriptional landscape despite limited clinical differences.

Further in silico analysis identified prevalent co-occurring mutations in NRAS mutant patients including, NPM1, FLT3 and epigenetic regulators DNMT3A, TET2, ASXL1. There were significant differences in OS between co-mutant subgroups and NRAS mutant patients. Notably, NRAS + ASXL1 co-mutant patients showed significantly reduced OS compared to NRAS mutant patients in both UKNCRI (p = 0.0007) and AML SG (p <0.0001) cohorts. This subgroup also had distinct clinical differences (age, sex, blasts percentage) and a unique transcriptional profile. There were 72 differentially expressed genes including upregulated LIN7A, AKT3 and downregulated GGT5, TRIM71. Subsequent pathway analysis identified 93 enriched pathways further supporting the altered landscape in NRAS + ASXL1 mutant patients.

In vitro validation was performed using CRISPR-Cas9 engineered NRASG12D and NRAS wild type THP-1 cell lines. Significant differences within the cell cycle phases were observed. Moreover, NRASG12D mutant cells were resistant to venetoclax (IC50 >1000 nM) compared to NRAS wild type cells (IC50 88.6 nM) indicating therapeutic resistance for NRAS mutant patients.

These findings highlight the importance of NRAS mutations and their co-mutations, particularly with ASXL1 in shaping disease outcomes in AML. Integrating these molecular profiles could enhance risk stratification systems and guide more effective treatment strategies. The dysregulated genes identified may act as potential biomarkers for disease monitoring or as novel therapeutic targets, offering a foundation for developing stratified treatment approaches for high-risk subgroups.

Date of Award	Jun 2025
Original language	English
Sponsors	Department for the Economy
Supervisor	Rachelle Irwin (Supervisor), Kyle Matchett (Supervisor) & Colum Walsh (Supervisor)