Oncogenic RIT1 mutations in lung adenocarcinoma

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Lung adenocarcinoma (LUAD) has known driver mutations in RTK/RAS pathway genes (KRAS, EGFR, BRAF, ERBB2) and fusions (ALK, RET, ROS1).
• Targeted therapies based on these mutations have improved LUAD treatment outcomes in stratified patient groups.
• Approximately 45% of LUAD cases lack these common driver mutations, indicating other oncogenic pathways are involved.

Purpose of the Study:

• To identify novel driver oncogenes in lung adenocarcinoma.
• To investigate the role of the RIT1 gene in LUAD pathogenesis.
• To explore potential therapeutic strategies for LUAD driven by RIT1 mutations.

Main Methods:

• Somatic mutation analysis of lung adenocarcinoma patient samples.
• Functional studies involving ectopic expression of mutated RIT1 in vitro and in vivo.
• Assessment of cellular transformation and drug sensitivity.

Main Results:

• Somatic mutations in the RIT1 gene were identified in approximately 2% of lung adenocarcinoma cases.
• These RIT1 mutations occurred in a hotspot near the switch II domain and were mutually exclusive with known LUAD driver mutations.
• Ectopic expression of mutated RIT1 induced cellular transformation, which was reversed by combined PI3K and MEK inhibition.

Conclusions:

• RIT1 acts as a driver oncogene in a subset of lung adenocarcinomas.
• RIT1 mutations represent a distinct molecular subtype of LUAD.
• Combined PI3K and MEK inhibition is a potential therapeutic approach for RIT1-mutated lung adenocarcinomas.