Well Populations and Flow – the Future?

Author: Christopher Black, Ph.D.; Published: Nov 19, 2010; Category: Flow Cytometry; Tags: Apoptosis, Cellular Pathways, Flow Cytometry; No Comments

Flow cytometry has long been used as a powerful cell analysis tool to examine complex populations such as immune cell distributions in the blood stream. With the ability to perform screens using flow cytometry, another interesting possibility exists in the application of this technique for drug screening. Specifically, given a single well in a multi-well plate, we can probe what the cell population distribution is in that well based on the responses of those cells.

Consider the treatment of a single cell line, such as Jurkat cells, with a chemical substance known to be toxic. Even at no concentrations of the chemical there will be cells that are in their death spirals among many healthy and viable cells. In other words, no cell population is completely homogenous. Increasing the incubation time as well as dose will cause more of these cells to enter these death spirals.

However, in every case where some cells exist, there are subpopulations of cells that are completely viable and intact. Any quadrant analysis will easily highlight this distribution. In fact, in this toxicity example, these cells may not have any upregulated stress pathways.

What then is it about these cells that allow them to be non-responders?  Measurements on standard plate readers do not allow for such a detailed understanding of cell population –in short, plate readers provide a total overall or summed response of a population.

Since each cell within a population may respond slightly differently to its environment, an understanding of these differences is crucial to building a new molecular approach. A technique like flow cytometry, with single cell resolution, can provide a better mechanistic understanding of how a compound or chemical affects individual cells.

For too long the industry has focused on isolated biochemical endpoints, ignoring the fact that a so-called cell line is not homogeneous and contains information that may be pertinent to the development of more effective, and safer, drugs.

Let’s take advantage of the fact that we can use whole cell models and powerful techniques like flow cytometry to probe these questions. The promise of analyzing interconnected pathways may be right around the corner.