By: Chiara Facciotto, Mila Hyytinen & Tiia Pelkonen

As the number of cancer therapies available on the market keeps increasing, finding ways to identify which drugs would be most beneficial for a specific patient is becoming fundamental. This is the promise of personalized medicine.

We discussed the topic with Daria Bulanova, a postdoctoral researcher, who has been working on testing drugs on cancer cells in the HERCULES project.

What is personalized medicine and how is your work related to it?

I think that a functional personalized medicine approach is about the ability to predict the response of a patient to certain drugs using functional testing. Functional precision medicine aims to find the most effective drugs for the individual patient.

As part of the research that we conduct at Krister Wennerberg’s research group (link to website), we are testing drugs on cancer cells directly isolated from patients. In some cases, we are even able to take sequential samples from the same person, so we can study the tumor at different stages of the disease progression. This allows us to identify drugs that a specific tumor is sensitive to.

How can you test the effect that multiple drugs would have on the same tumor?

First, I need to get the cells to grow outside the human body. Once they can be seeded to a multiwell plate, I can treat them with a collection of cancer drugs with different anti-cancer mode of action. We usually test about 600 cancer drugs or compounds that are candidates for or already in clinical trials. 

After a few days, I can test the effect that different drugs have, to identify which ones can kill cancer cells from this specific patient.

A multiwell plate
A multiwell plate used in drug screening (by Shinryuu from Wikimedia Commons)

The promise of personalized medicine is very alluring, but what are its current limitations?

In our work, one of the limitations of the current method is that it doesn’t allow to account for all the heterogeneity in tumors. For example, different sub-populations of cells with different mutations within the tumor have different responses to certain drugs. Also the location of different types of cells in relation to each other have an effect on tumor progression and sensitivity to drugs. (For more on tumor heterogeneity, see our previous post here.)

There is also a need to improve cell culture techniques to make drug testing more reliable, to make sure the cells do not change too much because of the culturing. Many things can happen between the operating room and research laboratory that can affect the results. So the best approach would be to obtain a sample which grows fast enough as a cell or organoid culture to be screened as soon as possible after sampling and which can also be somehow banked in a way that preserves the original characteristics of the sample.

Also, even drugs which have been approved for clinical use, but not for the disease or disease stage in question, still have to go through a clinical trial before they can be approved for a new use. This naturally takes time and investment. In the case of novel drug compounds, which have not been approved for any clinical use yet, the process is even longer. (See more about clinical trials in our previous post here.)

Future promise

At the moment, personalized medicine is still mainly limited to research settings, but technology is constantly progressing and will hopefully allow us to solve the current issues and scale up the solutions so that they can be made available for patient care in general.

Photo of Daria Bulanova
Daria Bulanova, postdoctoral researcher, previously at University of Helsinki, Finland, currently at University of Copenhagen, Denmark.