Dr. Karla Williams on Analyzing Extracellular Vesicles Using the CytoFLEX

Dr. Karla Williams, Asst. Professor
University of British Columbia Vancouver

So one of the big focuses of the lab is using extracellular vesicles as a detection platform so we're looking at these small particles that are released by most cells and we're looking at
different biomarker composition on these particles to say whether or not they reflect whether or not the tissue they came from was healthy or diseased. So we're interested in using extracellular
vesicles as a diagnostic and prognostic platform in various different types of cancers such as breast and prostate and we're hoping that learning more about these structures and about the biomarker composition of them is going to allow us to implement some new different types of screening tests and new different types of prognostic tests into the clinic. We definitely want to do the standard
validation methods that the community likes to see in terms of doing the electron microscopy so you can visualize how these structures look and the western blots to say "they have these
markers that we would expect to have on them" but one of the powerful things that the flow gives us is that we can look at a combination of markers on a single vesicle and that's really neat to be able to do because we can say where that vesicle came from with a tissue specific marker and then we can look at other proteins or carbohydrates on those vesicles that actually tell us something about an individual's health status. You can't really do that with any other technique to say this vesicle has this combination of markers.

It becomes a really powerful tool to give you a lot of information about an extracellular vesicle, from its origin to the different changes that have happened to that to that cell during a healthy or disease state. Using different markers on these extracellular vesicles we can determine whether or not someone has an aggressive form of cancer.

What it really comes down to is having a detection platform where you can look at this in a rapid way. So you want to be able to analyze a plasma sample and you want to be able to analyze the biomarkers on the extracellular vesicles without a lot of time-consuming techniques. And so we do a lot of flow cytometry on this, or nanoscale flow cytometry, which allows us to use antibodies against their antigens of interest and say are they present on these extracellular vesicles and then we do validation with some more standard methods to show you know these are truly EVs that we're looking at, that they contain our biomarkers of interest.

But we have this high-throughput platform where we can just run plasma with our antibodies of interest and we can see these populations and we see that these populations change depending on whether or not an individual is healthy or whether or not they have a disease state. So this is a really powerful platform and we've been finding that using the Cytoflex is really enabling us to advance our work on extracellular vesicles by allowing us to look at multiple markers on these vesicles and give us more information about the tissue that it came from, and we think that it's going to have huge applicability when we try to move this into a clinical setting.