Special Interest Group (SIG)
Screen Design and Assay Technology Special Interest Group (SIG)
Wednesday, February 7
8:00 AM - 9:15 AM
The goals of the Screen Design & Assay SIG are to: Share current best practices and experiences in the design of screens for high- and ultra high-throughput screening programs.
Provide a platform to encourage an open discussion among group members of any new screening technologies that can be beneficial to the screening community.
Encourage academic and industrial members to actively contribute to the SIG.
Identify any gaps in reagent(s) and instrumentation and/or in the screening environment, and seek to influence the appropriate supplier(s).
Evaluate new technologies and instruments on a voluntary basis and share findings at technology-based user group meetings on a more frequent basis.
The following will be presented during this session: “Lessons Learned from an HTS Campaign—Screening Strategy & Assay Development” by Ai Xi, PhD.
Lessons learned from an HTS Campaign -- screening strategy & assay development
Xi Ai, Yanqing Kan, Steven Cifelli, Richard Johnstone, Anthony Kreamer, Maria Webb, Jing Li, Mary Jo Wildey, Adam Weinglass
Screening & Compound Profiling, Merck Research Laboratories, Kenilworth, NJ 07033
High Throughput Screening (HTS) is a key driver for the identification of novel chemical matter in drug discovery. Optimizing the Screening Strategy, and individual assays in the funnel, maximizes probability of success. With respect to assays, several considerations must be taken into account including assay development, miniaturization, automation, quality control and informatics.
In the current study, a suite of assays were developed for a HTS aiming to identify suppressors of a target protein. Strategically, the goal of the primary assay was to measure suppression of the endogenously expressed target protein in physiologically relevant cells using antibodies (HTRF), with a back-up plan of using a highly related but engineered system (luciferase downstream of target protein in the same cells) as/if necessary. With this approach, the team had the flexibility to navigate timeline complexities, specifically; 1. Challenges in miniaturizing desired HTRF primary assay from 384- to 1536-well format while meeting assigned robotics schedule. Here, a strategy of performing a head-to-head 50 K diversity set screen in the two cell lines and assessing overlap builds team confidence in the engineered cell line and positions for 1536-well screening of larger compound sets using the luciferase approach (more sensitive in this case). 2. Queue ‘bumping’ issues. While miniaturization complexities pivoted team from HTRF to luciferase (1.), a higher priority project delaying our campaign provided us with the opportunity to use the time to continue optimizing primary assay miniaturization, hence moving us back to the HTRF assay.
Ultimately, primary screening was performed using a 260 K library against the successfully miniaturized HTRF in a 1536-well format. Screening proceeded using the most relevant cell type in a reasonably timely and efficient manner, but for a slight delay due to program prioritization, and by-passed the need for a “side-by-side” analysis. Flexibility & resilience within the context of assay development are valuable attributes to the screening scientist.