A targeted genetic modifier screen in Drosophila uncovers vulnerabilities in a genetically complex model of colon
Ishwaree Datta1, Tajah Vassel1, Benjamin Linkous1
1Department of Biological Science, Florida State University, Tallahassee, FL 32304, USA.
Abstract:
Received on 16 January 2023; accepted on 21 February 2023Kinases are key regulators of cellular signal transduction pathways. Many diseases, including cancer, are associated with global alterations in protein phosphorylation networks. As a result, kinases are frequent targets of drug discovery efforts. However, target identification and assessment, a critical step in targeted drug discovery that involves identifying essential genetic mediators of disease phenotypes, can be challenging in complex, heterogeneous diseases like cancer, where multiple concurrent genomic alterations are common. Drosophila is a particularly useful genetic model system to identify novel regulators of biological processes through unbiased genetic screens. Here, we report 2 classic genetic modifier screens focusing on the Drosophila kinome to identify kinase regulators in 2 different backgrounds: KRAS TP53 PTEN APC, a multigenic cancer model that targets 4 genes recurrently mutated in human colon tumors and KRAS alone, a simpler model that targets one of the most frequently altered pathways in cancer. These screens identified hits unique to each model and one shared by both, emphasizing the importance of capturing the genetic complexity of human tumor genome landscapes in experimental models. Our follow-up analysis of 2 hits from the KRAS-only screen suggests that classical genetic modifier screens in heterozygous mutant backgrounds that result in a modest, nonlethal reduction in candidate gene activity in the context of a whole animal-a key goal of systemic drug treatment-may be a particularly useful approach to identify the most rate-limiting genetic vulnerabilities in disease models as ideal candidate drug targets.
Insights
Genetic screens in Drosophila identified kinase regulators for cancer drug discovery. Modest gene activity reduction in models revealed key genetic vulnerabilities, aiding target identification for complex diseases.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- Kinases regulate cellular signaling and are crucial in diseases like cancer.
- Identifying drug targets in complex cancers with multiple genetic alterations is challenging.
- Drosophila melanogaster serves as a powerful genetic model for unbiased screens.
Purpose of the Study:
- To identify novel kinase regulators using Drosophila genetic screens.
- To compare kinase targets in a complex multigenic cancer model versus a simpler KRAS-driven model.
- To evaluate the utility of genetic modifier screens for identifying cancer drug targets.
Main Methods:
- Conducted two classic genetic modifier screens targeting the Drosophila kinome.
- Utilized two distinct cancer models: a multigenic (KRAS TP53 PTEN APC) and a single-gene (KRAS) background.
- Performed follow-up analysis on identified kinase hits from the KRAS-only screen.
Main Results:
- Identified unique and shared kinase regulators across both cancer models.
- Highlighted the importance of modeling human tumor genetic complexity in experimental systems.
- Follow-up analysis suggested heterozygous mutant screens reveal rate-limiting genetic vulnerabilities.
Conclusions:
- Genetic modifier screens in Drosophila are effective for identifying kinase regulators in cancer.
- Modeling genetic complexity is crucial for discovering relevant drug targets.
- This approach can identify optimal candidate drug targets by revealing rate-limiting genetic vulnerabilities.
