RIT1 Drives Oncogenic Transformation and Is an Actionable Target in Lung Adenocarcinoma

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• RIT1, a RAS family GTPase, is implicated in lung cancer, leukemia, and Noonan syndrome.
• RIT1 mutations increase protein levels via impaired proteolysis, disrupting RAS/MAPK signaling.
• RIT1 acts as an oncogene, promoting lung tumorigenesis.

Purpose of the Study:

• To investigate the diversity of RIT1 mutations in human lung cancer.
• To assess the oncogenic potential of RIT1 mutations in vivo.
• To evaluate therapeutic strategies targeting RIT1 or downstream pathways.

Main Methods:

• Documented RIT1 mutation diversity in human lung cancer.
• Utilized mouse models to study RIT1 M90I-driven lung tumor development.
• Evaluated direct RIT1 inhibition and downstream RAS/MAPK pathway inhibition.
• Employed chemical biology to identify RAS tri-complex inhibitors targeting RIT1.

Main Results:

• Physiologic expression of RIT1 M90I drives autochthonous lung tumor development in vivo.
• RIT1 M90I tumors are sensitive to SHP2 inhibitors and RAS nucleotide exchange inhibitors.
• RAS tri-complex inhibitors bind GTP-bound RIT1, leading to tumor shrinkage.

Conclusions:

• RIT1 is a bona fide oncogene in lung cancer.
• Targeting RIT1 directly with RAS tri-complex inhibitors is a feasible therapeutic approach for RIT1-driven lung tumors.