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Flow Cytometry Powers High-Throughput Screening Advances

"We are all tasked with finding new drugs that can differentiate our companies and provide real benefit to patients," says John Joslin, research investigator at the Genomics Institute of the Novartis Research Foundation (GNF), San Diego, CA. "To do so, we need to establish biologically relevant screening assays for our high-throughput screening campaigns. However, increasing the biological relevance leads to more complex biology that requires new methodologies for lead identification and our screening systems must evolve to meet this challenge."

 

High-throughput screening (HTS) has transformed drug discovery. Since bursting on the scene in the late 1980s/early 1990s and with incredible advances in automation, miniaturization and robotics, creative scientists continue to find ways to achieve more from this research technology.

"Add stuff to stuff and see the results. Scientists have been doing that for a hundred years, but now it's not 10 experiments a week but a million," says Vic Myer, director, Developmental and Molecular Pathways at Novartis, in a recent white paper explaining the shift change that HTS brought to drug discovery.

For Joslin, it is the integration of flow cytometry into HTS efforts that has made a difference in his work.

"Flow cytometry is a very powerful tool that has been used for decades, and allows for multiparametric readouts at the single cell level within heterogeneous cell populations," Joslin states. "However, in the context of high-throughput screening, flow cytometry has traditionally been slow, low-throughput and not amenable to automation. The Novartis fully automated screening system solved that problem.

"Our team developed a fully automated flow cytometry sampling workflow that is compatible with 1536 or 384 well plates," Joslin continues. "Progressive high-content screening systems have been demonstrated to process up to 50,000 wells/day on a routine basis with screening campaigns into the millions of wells, but this has been limited to adherent cells."

Joslin describes the Novartis solution in the Sept. 23 SLAS Webinar, "Development of a Fully Automated Ultra-High Throughput Flow Cytometry Screening System to Enable Novel Drug Discovery." He discusses the automated screening system, an industry first, dedicated to processing and reading suspension cells using flow cytometry. The custom samplers are fully integrated into a GNF Systems ultra-high throughput screening system and feed three Beckman Coulter CyAn cytometers. This system can read a 384 well plate in 15 min and a 1536 well plate in less than an hour. This allows for a throughput of approximately 40,000 wells per day with less than one full time employee overseeing the system. Also presented in the SLAS Webinar is an overview of informatics tools used to process the large amount of data in real-time and in a fully automated workflow. As a result of this effort, Novartis is running high-throughput flow cytometry phenotypic screens across multiple disease areas to enable novel drug discovery.

"One of the first screens we ran on the system was focused on human hematopoietic stem cell self-renewal," Joslin explains. "The holy-grail in the field has been to identify a small molecule that could cause stem cells to expand while maintaining their pluripotency. To date, we have screened approximately 1 million compounds and have been able to identify a compound that expands primary human hematopoietic stem cells. This compound can now be used to expand the small number of stem cells from cord blood samples so that there are enough stem cells for an adult recipient. This effectively increases the number of donors and the likelihood of finding a match for adult bone marrow transplant patients. The compound is currently in clinical trials and we are very excited about the success to date for this program."

What's Next?

"Fully automated flow cytometry is still a very new concept," Joslin notes. "The flow cytometer manufacturers did not fully envision automation when they initially developed the software or hardware. There was always the expectation that the user would be standing in front of the device or would be returning soon. While there are a few companies that have enabled their devices to work in this environment, there is still room for improvement and innovation. We are working to increase access and control of the cytometer in an automated manner so that we can increase the throughput and quality control of the screens we run.

"This Novartis system is best suited to interrogate complex assays where a single readout is insufficient," Joslin continues. "As an example, our system can quantitate changes in the expression of multiple cytokines from a single well, enabling a specific response profile to be identified. However, if we are only interested in measuring changes of a single cytokine, there are other technologies that can enable this in a higher throughput manner."

Joslin is equipped well to move this technology forward. He earned his Ph.D. in cancer biology from the University of Chicago Biological Sciences Division, where he studied cancer biology and focused on therapy-related acute myeloid leukemia. Joslin then joined GNF and performed post-doctoral research focused on autoimmunity looking for novel regulators of T-helper cell regulation. He currently is a GNF research investigator leading a group of scientists in early target validation, technology development and assay miniaturization for high-throughput screening.

"As a scientist, I always enjoy asking hard questions and looking at problems from a different point of view," Joslin says. "We now have a powerful tool to do just that in a highly automated and high-throughout manner."

Learn More in the SLAS Webinar

Development of a Fully Automated Ultra-High Throughput Flow Cytometry Screening System to Enable Novel Drug Discovery
September 23, 2014
11:30 a.m. EDT
Sponsored by IntelliCyt Corporation

Registration is free for dues-paid SLAS members, both live on Sept. 23 and following at SLAS On Demand. Not yet an SLAS dues-paying member? Become one today and enjoy member benefits through end 2015.

"This webinar is for anyone who would like to learn how to use flow cytometry in a fully automated and high-throughput environment," Joslin explains. "I will give an overview of our screening system, discuss some real-life examples and discuss our view for the future for flow cytometry in HTS."

August 27, 2014