Direct genome editing of patient-derived xenografts using CRISPR-Cas9 enables rapid in vivo functional genomics

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Patient-derived xenografts (PDXs) are valuable in vivo models for human cancer research.
• Current limitations include the inability to perform targeted genome editing in PDXs.
• This restricts their utility compared to cell lines or genetically engineered mouse models.

Purpose of the Study:

• To develop a method for CRISPR-Cas9 genome editing in PDXs.
• To enable targeted genetic modification of PDXs without in vitro culture.
• To enhance the utility of PDXs as genetically programmable cancer models.

Main Methods:

• Developed a tightly regulated, inducible Cas9 vector for CRISPR-Cas9 editing.
• Applied the system to PDXs, demonstrating its efficacy without requiring in vitro selection.
• Utilized targeted gene disruption and site-specific gene editing via homology-directed repair.

Main Results:

• Successfully implemented CRISPR-Cas9 editing in PDXs.
• Demonstrated the ability to analyze genetic dependencies through gene disruption.
• Showcased the analysis of acquired drug resistance mechanisms via precise gene editing.

Conclusions:

• The developed CRISPR-Cas9 platform significantly enhances the utility of PDXs.
• This system allows for genetically programmable manipulation of PDXs.
• The approach has broad applicability to other explant models in cancer research.