Rapid Identification of Chemoresistance Mechanisms Using Yeast DNA Repair Mutants

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Rapid Identification of Chemoresistance Mechanisms Using Yeast DNA Repair Mutants

Princeton Docket # 15-3160


Researchers in the Department of Molecular Biology at Princeton University have identified drug resistance mutations in key pathways in chemoresistance using the mutator phenotype of mismatch repair defective Saccharomyces cerevisiae cells and whole genome sequencing.  The utility of this approach was demonstrated via the identification of the known CAN1 andTOP1 drug resistance targets for two compounds, canavanine and camptothecin, respectively.  The sequencing of mitoxantrone-resistant strains identified mutations within IPT1, a gene encoding inositol-phosphotransferase, an enzyme involved in sphingolipid biosynthesis. Importantly, having identified the primary drug resistance target, the researchers showed that it is possible to exploit that vulnerability to prevent chemoresistance from forming.  For example, they were able to prove that co-treating cells with low levels of rapamycin, an mTOR inhibitor, prevents the formation of mitoxantrone resistance.


The developed cell-based DNA repair mutant assay can be used to identify drug resistance mechanisms for existing and novel drugs. Furthermore, identifying the drug resistance target will facilitate the discovery and development of effective drug combination therapeutic regimes that will prevent chemoresistance from forming.



·       Identify cause and mechanism of drug resistance for existing and novel compounds in development

·       Rationally develop combination therapies to prevent chemoresistance

·       Cell-based DNA repair mutant assays as anticancer and drug resistance discovery platform


·       Rapid, robust, and systematic approach with whole genome sequencing

·       Facile process to identify and validate drug resistance mechanisms

·       Yeast as model organism amenable to genetic manipulation

·       Improvement to chemical mutagenesis and high throughput screening of yeast deletion collection of mutants

Key Words


Chemoresistance, drug discovery, drug development, drug resistance mechanism, whole genome sequencing, DNA mismatch repair, combination therapy, yeast




Alison Gammie, Ph.D. and Irene Ojini


Faculty Inventor


Alison Gammie, Senior Lecturer in Molecular Biology and Associate Clinical Member, Cancer Institute of New Jersey, Genome Instability and Tumor Progression

Research in the Gammie lab focuses on DNA mismatch repair, including the regulation of DNA mismatch repair proteins and the mechanism of DNA mismatch repair recognition during replication.  Mismatch repair includes identification of a mismatch in the DNA helix, followed by cleavage and excision of the error-containing strand.  After the error is removed, a new DNA strand with correct base pairing is synthesized.  Because many cancers, particularly those of the colon, are caused by defects in DNA mismatch repair, the Gammie lab seeks to understand oncogenesis in both hereditary and sporadic tumors.  Yeast is an optimal experimental organism for studying eukaryotic mismatch repair, as it is amenable to genetic manipulation and has strong homology to the human mismatch repair system.  Chromatin immunoprecipitation, tiling microarrays, and high throughput sequencing are other biochemical and molecular tools employed to address questions in DNA mismatch repair.


Dr. Gammie has been a Senior Lecturer at Princeton University since 1998 and was previously a postdoctoral research associate within the Department of Molecular Biology.  She is currently the Director of the Program for Diversity and Graduate Recruitment in Molecular and Quantitative Biology, the Director of the Summer Undergraduate Research Program in Molecular and Quantitative Biology, and the NIH Diversity Action Plan Coordinator for the Lewis-Sigler Institute for Integrative Genomics.  Additionally, she is the instructor for an inquiry-based laboratory course for graduate students.  Dr. Gammie has been recognized for her excellence in mentoring and teaching.  In 2013, she was awarded the Princeton University Graduate Mentoring Award and the American Society for Microbiology William A. Hinton Research Training Award.  She received her Ph.D. in Molecular Biology from Oregon Health Sciences University and her B.A. in Biology from Reed College.


Intellectual Property Status


Patent applications are pending.  Princeton is seeking industrial collaborators for further development and commercialization of this technology.




Laurie Tzodikov
Princeton University Office of Technology Licensing • (609) 258-7256•


Sarah Johnson

Princeton University Office of Technology Licensing • sajohnso@princeton.edu



Patent Information:
For Information, Contact:
Laurie Tzodikov
Licensing Associates
Princeton University
Alison Gammie
Irene Ojini
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