Sylvie Guichard: CRISPR technology in a day of our lives as researchers
Ever wondered what a day in the life of a researcher in Big Pharma looks like? Especially on that’s looking to apply gene editing technology. Sylvie Guichard of AstraZeneca takes us through a day in her life…
I am on my way to work and even amongst the fumes of I-95, I can feel spring. I listen distractedly to a podcast from the BBC World Service when suddenly the word “CRISPR” permeates my brain. The BBC? CRISPR? Professor Matthew Cobb is explaining how CRISPR has revolutionised the way researchers at Manchester University tackle threatening diseases like cardiovascular disease, cystic fibrosis and cancer.
This takes me back to late 2013 when Susan Galbraith, Head of the Oncology Research and Development and Mene Pangalos, Head of the global IMED (Innovative Medicine & Early Discovery) Department at AstraZeneca agreed to support key collaborations with experts in CRISPR/Cas9. My proposal in collaboration with Professor David Sabatini, at the Whitehead Institute/MIT, was to explore the Achilles heel of some types of cancers using CRISPR/Cas9 on a genome-wide scale to identify new drug targets. My colleague, Lorenz Mayr, was similarly engaged in discussions with the Sanger Institute in the UK, UC Berkeley/UC San Francisco and LifeTechnologies/ThermoFisher.
Fast forward two years, and we are at the first Sanger InstituteAstraZeneca CRISPR conference in Cambridge over in the UK. It is buzzing! Everyone is talking about the data the could be presented for the first time, asking questions, exchanging tips and email addresses. The atmosphere is incredible. It’s like we are all part of this adventure, and learning from each other will be key to progress as fast as possible.
I have a monthly call with colleagues. We exchange the latest data our respective teams have generated and new data emerging from the collaborations. Working alongside our collaborators gives us a sense of just how fast this field of research is progressing at AstraZeneca and outside AstraZeneca (including academia and other Pharma/Biotech companies). We discuss reagents, protocols, follow ups, and new projects.
I scan the daily summary of publication searches on CRISPR/Cas9 and post a few links to our local “twitter”. I get a few replies. They usually include,“on it”, “I think some controls are missing, will catch you later to discuss”, “this looks super-cool”. In my work, I try to identify the drugs of tomorrow.
I’m trying to understand why patients treated with drug X don’t respond. What is special about the makeup of their cancer cells? What are the important functions of those cells? Can we target them to try to kill the cells?
Cancer cells may express mutant versions of a particular protein (also called oncogenes) that keeps them in an activated state beneficial to their growth and proliferation. Blocking the mutant version of the protein can be an effective way of killing tumour cells. But what if it is the loss or inactivation of a protein which help cells become cancerous? Tumour suppressor genes are inactivated or deleted in some tumours. When this happens tumour cells may come to rely on other proteins to make up for this loss. Targeting these proteins with drugs can selectively kill the tumour cells, while sparing the normal cells. But how do we find these key proteins in tumours which have a loss of tumour suppressor genes? CRISPR/Cas9 gives us the ability to delete every single gene in our genome using CRISPR/Cas9 libraries and to detect if this results in cell death specifically in tumours which have lost tumour suppressors. This could help us identify a new wave of drug targets.
Drug targets are often enzymes functioning as ‘engines’ modulating other key molecules in the cells. However, their ’engine’ is not always required. A drug modulating just the enzyme activity may not have the desired therapeutic benefit. CRISPR/Cas9 is so precise that we can ask whether it is the enzyme activity of a protein which matters or just the contacts it makes with other proteins. Understanding the drug targets where enzymatic activity is key for cancer cells can help us focus on the right targets.
One of my colleagues, and early adopter of CRISPR/Cas9, stops by my desk and gives me an update on his experiments. I want to see the data… “Team meeting, 2 pm” and he is gone. My phone rings and it is one of my colleagues in the UK. He is calling with an update on the CRISPR cell line generation for one of my projects. Making CRISPR cell lines is by no means simple, but it is becoming much simpler… or more precisely, we are asking for more and more complex gene editing and the answer is “it should be feasible”. And it is! One recent example is MTH1. Depletion of MTH1 protein using siRNA was reported to induce cell death in some cancer cell lines. Could MTH1 be a new drug target? The team generated a knockout version of MTH1 using CRISPR/Cas91. The cells were proliferating similarly with or without MTH1 which raised suspicion that the siRNA may have had off target activity. (De)validation using CRISPR/Cas9 is extremely important. It helps us focus our efforts on the best targets, the ones which may ultimately help us treat cancer patients.
Lab meeting…We have been to testing different CRISPR reagents to demonstrate their applicability to target validation which traditionally used siRNA. If we want scientists across the company to use CRISPR/Cas9, we need to make it as simple and robust as possible for them. The innovation in CRISPR/Cas9 reagents has been incredible and has given us the ability to tailor reagents to specific targets.
While some of our experiments test genes in which deletion can reduce proliferation of cancer cells, deletion of others can decrease drug sensitivity. Some of these genes were identified using cells from KO mice but the results could not be repeated using siRNA. Now CRISPR/Cas9 gives us a chance to revisit these genes in cancer cells which are more relevant to the patients we are hoping to treat. The discussions at the lab meeting are always lively, people challenge each other but ultimately we work as a team. Team meetings are one of my favorite times…
I am heading home reflecting on CRISPR and how it has permeated every aspect of drug discovery. There is still a lot to learn but we need to keep our focus on developing new therapies to help cancer patients. Working with expert scientists in CRISPR technology is a fantastic boost to our ability to achieve this goal.
Associate Director, AstraZeneca
“I am an Associate Director at AstraZeneca in the Oncology Innovative Medicine Unit in Boston. I lead a number of drug discovery projects but one aspect of my work is also to manage the portfolio of early drug targets in oncology and to identify new genetic vulnerabilities in cancer cells which could be exploited therapeutically. Genomics has been an essential tool to identify new drug targets or identify patient populations which would benefit from targeted agents. My interest in CRISPR/Cas9 started very much like many people as a tool to identify drug targets in tumours with loss-of-function mutations. However, I realised very quickly the potential of CRISPR as a therapeutic approach. Earlier in my career, I worked with antisense oligonucleotides and VDEPT. I formally trained as a pharmacist and have a PhD in molecular Pharmacology and have a keen interest in a broad range of therapeutic modalities to deliver drugs to patients.”