Project description:The discovery of oncogene addiction in cancer has led to the development of over a dozen FDA-approved biomarker-driven therapies in lung adenocarcinoma, but many rare driver mutations remain untargeted. Somatic mutations of the “Ras-like in all tissues” (RIT1) gene are non-canonical driver events in lung cancer, occurring in ~2% of lung adenocarcinomas in a mutually exclusive fashion with KRAS and EGFR mutations. Patients with RIT1-mutant lung cancer lack targeted therapy treatment options, and a lack of pre-clinical models has hindered the development of therapeutic strategies for RIT1-mutant lung cancer. Here we report a new mouse model with inducible regulation of the cancer-associated RIT1M90I variant. We show that autochthonous expression of RIT1M90I in the lung weakly promotes cancer alone or in combination with loss of the p53 tumor suppressor. However, potent synergy between RIT1M90I and inactivation of Nf2 and p53 drives an aggressive lung cancer with 100% penetrance and short latency. We show this oncogenic cooperation is driven by synergistic activation of cJUN, a component of the AP-1 complex. Therapeutic inhibition of MEK and YAP/TEAD suppressed RIT1M90I-driven lung cancer in vitro and in vivo. These data identify YAP/TEAD as an important mediator of RIT1’s oncogenic potential and nominate TEAD as an important drug target in RIT1-mutant lung cancer.
Project description:The discovery of oncogene addiction in cancer has led to the development of over a dozen FDA-approved biomarker-driven therapies in lung adenocarcinoma, but many rare driver mutations remain untargeted. Somatic mutations of the “Ras-like in all tissues” (RIT1) gene are non-canonical driver events in lung cancer, occurring in ~2% of lung adenocarcinomas in a mutually exclusive fashion with KRAS and EGFR mutations. Patients with RIT1-mutant lung cancer lack targeted therapy treatment options, and a lack of pre-clinical models has hindered the development of therapeutic strategies for RIT1-mutant lung cancer. Here we report a new mouse model with inducible regulation of the cancer-associated RIT1M90I variant. We show that autochthonous expression of RIT1M90I in the lung weakly promotes cancer alone or in combination with loss of the p53 tumor suppressor. However, potent synergy between RIT1M90I and inactivation of Nf2 and p53 drives an aggressive lung cancer with 100% penetrance and short latency. We show this oncogenic cooperation is driven by synergistic activation of cJUN, a component of the AP-1 complex. Therapeutic inhibition of MEK and YAP/TEAD suppressed RIT1M90I-driven lung cancer in vitro and in vivo. These data identify YAP/TEAD as an important mediator of RIT1’s oncogenic potential and nominate TEAD as an important drug target in RIT1-mutant lung cancer.
Project description:RIT1 is a small GTPase of the RAS family and RIT1 mutations have been identified in lung cancer, leukemias, and the developmental disorder Noonan syndrome. Mutations in RIT1 lead to increased levels of this oncoprotein due to impaired proteolysis, resulting in dysregulation of RAS/MAPK and other pathways. Here we document the diversity of RIT1 mutations in human lung cancer and show that physiologic expression of RIT1 M90I is sufficient to drive autochthonous lung tumor development in vivo in mouse models. Due to the current lack of targeted therapies for this oncoprotein, we undertake different and complementary methods to either inhibit RIT1 directly or the downstream RAS/MAPK pathway. Through a proof-of-concept chemical biology approach, we discover that RAS tri-complex inhibitors bind directly to GTP-bound RIT1 and lead to tumor shrinkage. These molecules provide a feasible therapeutic approach for RIT1-driven lung tumors.
Project description:RIT1 is a small GTPase of the RAS family and RIT1 mutations have been identified in lung cancer, leukemias, and the developmental disorder Noonan syndrome. Mutations in RIT1 lead to increased levels of this oncoprotein due to impaired proteolysis, resulting in dysregulation of RAS/MAPK and other pathways. Here we document the diversity of RIT1 mutations in human lung cancer and show that physiologic expression of RIT1 M90I is sufficient to drive autochthonous lung tumor development in vivo in mouse models. Due to the current lack of targeted therapies for this oncoprotein, we undertake different and complementary methods to either inhibit RIT1 directly or the downstream RAS/MAPK pathway. Through a proof-of-concept chemical biology approach, we discover that RAS tri-complex inhibitors bind directly to GTP-bound RIT1 and lead to tumor shrinkage. These molecules provide a feasible therapeutic approach for RIT1-driven lung tumors.
Project description:Human RIT1 was tagged with HA tag + N or C terminal ubiquitin (HA-Ubiqutin-RIT1 and HA-RIT1-Ubiqutin) and compared with empty vector (EV) or S35N/M90I RIT1 mutant (HA-RIT1 S35N/M90I). The constructs were expressed in human 293T cells and affinity purified using HA beads. RIT1 interacting proteins were compared by quantifying MS1 extracted chromatograms of peptides identified in conventional target-decoy database search.
Project description:This SuperSeries is composed of the following subset Series: GSE32727: EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors [human] GSE32904: EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors [mouse] Refer to individual Series
Project description:To investigate the impact of mutant RIT1 expression in cardiac cells, we isolated neonatal cardiomyocytes from mice harbouring an engineered Rit1 locus with Cre recombinase-inducible expression of the pathogenic variant Rit1M90I. Upon isolation, cardiomyocytes were treated with adenoviruses encoding for Cre recombinase to induce expression of the Rit1M90I variant.