Bevin Page Engelward
Faculty at the Massachusetts Institute of Technology
Title: Novel Cytotoxicity and Broad-Spectrum Genotoxicity Platforms
Biography
Biography: Bevin Page Engelward
Abstract
Toxicity and Genotoxicity testing are fundamental to drug safety and drug development. Here, we leverage cell microarray technology to create a robust and highly sensitive cytotoxicity platform and a broad-spectrum genotoxicity platform.
• Quantification of cell viability is one of the most fundamental and broadly used endpoints in the life sciences. The gold standard is the colony forming assay. While the assay has an impressive dynamic range (over several orders of magnitude), it is relatively low-throughput (10-21 days), laborious and requires large dishes/high volumes of media, thus requiring large amounts of test compounds.
• Microtiter cytotoxicity assay have thus been developed, including the XTT and the CellTiter-Glo assays. The XTT assay suffers from low sensitivity, and the CellTiter-Glo assay is subject to artifacts due to its indirect measure of cell viability.
• To overcome these limitations, we developed the MicroColonyChip (uCC) assay, which directly measures the ability of cells to divide (like the gold-standard colony forming assay), but with the scale and speed of microtiter assays. Microcolonies grow in a microarray and toxicity is derived using a novel metric, namely the change in the distribution of microcolony sizes. The result is an exquisitely sensitive assay that is robust to artifacts.
• For genotoxicity testing, the comet assay is a commonly used approach. We recently developed a higher throughput version of the comet assay that exploits a cell microarray. The “CometChip” is more than 1000X faster, far more sensitive and includes automated data analysis. Further, we broadened the spectrum of detectable lesions to include bulky lesions, a class of DNA damaging agents that has the potential to cause cancer.
Accurate cytotoxicity and genotoxicity testing hold a central role in drug development. Having reliable and sensitive assays enables identification of untoward deleterious effects of drug candidates, providing immense savings by narrowing the candidate pool. Further, cytotoxicity and genotoxicity assays are also pivotal for development of novel DNA damaging chemotherapeutics, the mainstay of cancer treatment today.