Breast cancer researchers at UMC Utrecht have discovered that a certain protein can predict whether a course of chemo will be effective for aggressive breast cancer. Women with breast cancer and a high level of FER protein have a greater chance of successful treatment with taxane chemotherapy. The results of this study were published in the renowned scientific journal Cell Reports.
Triple-negative breast cancer is an aggressive type of breast cancer. Women with triple-negative breast cancer often receive treatment with chemotherapy. The goal of the chemotherapy is to reduce the risk of metastasis (spread of the cancer) as far as possible, which increases the chances of survival.
The treatment with chemotherapy is not equally effective for all women. Many women also often suffer unpleasant side effects, such as fatigue, anemia, nausea, and hair loss. “It would be really helpful if we could predict whether a treatment with chemotherapy will be effective,” explains Patrick Derksen, professor of pre-clinical oncology at UMC Utrecht.
High FER protein, greater benefit of chemotherapy
His research group discovered that a certain protein could predict whether a course of chemo will be effective for triple-negative tumors. Women with breast cancer and high levels of the so-called “FER protein” will benefit more from treatment with chemotherapy.
Specifically, they will benefit from chemotherapy with taxanes, a type of medication that slows down cell division. “The FER protein basically recycles other proteins that the cancer cells need to be able to spread,” Derksen explains. “The taxanes slow down this process.”
Test that indicates whether chemotherapy will be beneficial
The researchers are now working on developing a test that demonstrates whether a triple-negative breast tumor has high or low levels of FER protein. High levels of FER equate to a greater probability of the taxane chemotherapy being effective.
Derksen: “We want to start using the test right from the moment of diagnosis, so that we can offer a more tailored treatment. The test is performed in the lab on collected tumor material. We do not need to ask the patients to do anything extra. We will conduct clinical trials on this test, to confirm our prediction and so be able to offer a more personalized and effective treatment.”
The ultimate goal of the Mechano·Control project is to be able to abrogate breast tumour progression. To do that, it is very important to apply the Mechano·Control findings at different scales, from single molecules and all the way up to the organism and patient level. For that, Thijs Koorman, a senior postdoc at the DerksenLab at the UMC Utrecht, will perform fundamental and preclinical research within in the Mechano Control project. His main goal is to translate basic findings with therapeutic potential to target invasive breast cancer. With this interview, we are going to take a step forward and get a closer look to the animal and human models, the largest scale of the Mechano·Control consortium.
Dr. Thijs Koorman runs a variety of different tasks. But first, let’s get to know a little bit more about their role in the Mechano·Control consortium. The main aim within the DerksenLab is to translate the molecular findings within the Mechano·Control project to animal and human models of invasive breast cancer. This group has a fundamental to translational focus. They provide proof of concept in preclinical models of breast cancer and test novel candidate targeted therapeutic interventions identified within Mechano·Control.
With this in mind, Thijs together with Dr. Daan Visser (technician within the Mechano Control consortium) test the therapeutic potential of the identified molecules in the consortium with the hope to obtain pre-clinical data that can be used to ultimately better treat patients suffering from invasive breast cancer.
And how is this translated into the lab?
“We culture mouse and human organotypic cancer models in both 2D and 3D. The models used represent the two types of invasive breast cancer. As such, they harbour all aspects of human invasive breast cancer, which we study using molecular biochemistry and microscopy”, explains Thijs.
In particular, Thijs studies the molecular and signalling composition of cell adhesion proteins and how disruption of this complex potentiates oncogenic signalling. For this he uses 2D and 3D organotypic tumor models and preclinical mouse models of invasive breast cancer. The group has a deep interest in how loss of mechano-transducing cell-cell and cell-matrix contacts drive to invasive breast cancers, focussing on lobular carcinoma. The groups has generated a breast cancer sample databaseof over 2000 patients and collected tumour material of over >1000 patients to test molecular markers.
Until now, Thijs and the researchers at the Derksen Lab have discovered a molecular mechanism that explains how invasive breast cancer cells may stop dividing and linger in the body for years and what triggers expansion at the metastatic site. Now, they are probing how to target these “sleeping cells” during dissemination and stop the growing cells with therapeutics.
Discovery-based fundamental science is essential to establish the building blocks of therapeutic interventions. “We aim to bridge both aspects, understanding the molecular signalling and discovering or identifying the means to target them. Most importantly, we have the tools to test such in our clinical mouse models and all subtypes of invasive breast cancer. Being able to make these translational steps fast and efficient is a unique aspect of our work” says Thijs.
Thijs also supports the day-to-day supervision of bachelor, master and the Ph.D. students. He also teaches a variety of undergraduate classes at Utrecht University. Thijs also manages the clinical outsourcing and dissemination, including patient advocate involvement. Thijs also holds a leadership position within the COST Action Lobsterpot (CA19138), an initiative of the European Lobular Breast Cancer Consortium (www.elbcc.org).
According to Thijs, being a part of the Mechano·Control consortium is a thrill and a great opportunity to work with colleagues all over the world that work at very different scales. “A single email, text or conversation is sufficient to spark new ideas or endeavours. Combining all of our skills and thinking outside the box is exciting. Not only for your own development, but also to obtain new views on scientific problems. We have a collaborative spirit and were able to test a lot of hypotheses which otherwise would not have been tested.”
In biomedical research, it is important to mimic the conditions that are found in our body. Traditionally, scientists have used 2D in vitro models where they grew cells on flat surfaces. However, as it can obviously be observed, the cells in our body are in three-dimension. So, wouldn’t it be amazing to create 3D models to study diseases, such as breast cancer?
Antoine Khalil is a senior Post-Doc at the UMC Utrecht in the Netherlands, in Johan de Rooij’s group. Their first and very important role at the Mechano·Control consortium was to establish the 3D in vitro models that recapitulate the characteristics of breast cancer in patients. They have used pieces of tumors (organoids) and grew them in 3D extracellular matrix (ECM). The ECM is a complex network of proteins that surround the cells in our body and provide important signals that control cell behavior. Antoine and his colleagues have characterized these cancer organoids and are trying to understand the nature of the extracellular matrix (ECM) that leads to cancer invasion and metastasis.
Working with organoids and 3D ECM makes in vitro studies more reliable, because they retain several aspects of tumor characteristics, and because most of the invasion that takes place in cancer patients, occurs in a 3D environment. The researchers can manipulate these organoids with the aim to stop the ability of cancer cells to become invasive and therefore, this will provide therapeutic opportunities to target the spread of the tumor cells throughout the body.
“We use a new type of model system for our research that is called organoid culture. Organoids are made from biopsy materials that are isolated from breast tumors in human patients or mouse models. In this way, we can grow a piece of tumor in a controlled environment and study the effects of specific ECM conditions on the induction of tumor cell invasion”, explains Antoine.
Invasion and spread of breast cancer into the surrounding breast tissue often happen in groups of cells (collective invasion). The invasion of the cancer cell groups is driven and guided by few specialized cancer cells called the leader cells. Antoine and his colleagues have identified and fluorescently-tagged molecules that are exclusively expressed in those leader cells. They also found that several of these molecules are activated by changes in the ECM stiffness and tension. Thanks to that, several of these models and markers are being used by the other members and institutions of the Mechano·Control project.
Antoine and his colleagues aim to unravel the molecules that are most important in the transition to an invasive leader cell state and suggest methods to interfere with this process to prevent breast cancer invasion and metastasis.
The “life-time” of a tumor goes through different stages: In the first stage, the tumor grows in an uncontrolled fashion. In this stage the tumor is still confined and the cancer cells remain at their site of origin. At a later stage, some cancer cells within the tumor undergo a transformation that makes them motile and invasive. When this happens, tumor cells can spread to different regions in the body (including lungs, liver and brain) to form secondary tumors (metastases). That is why understanding how invasion is regulated will allow blocking it and this is very important to prevent and reduce metastasis.
It is now very well known that stiffer extracellular matrices surrounding breast tumors strongly associates with breast cancer invasion. “Our major task in the Mechano·control project is to unravel the molecular machinery in breast cancer cells that is essential for ECM sensing and the acquisition of invasive behavior”.
Until now, their data has established that only a pre-defined subset of breast tumor cells (the basal cells) (Figure 1, yellow) can become the leaders of invasion (Figure 1, white arrowheads). These leader cells drive the movement of groups of cancer cells. Antoine’s work shows that becoming a leader cell is triggered by changes in biochemical and mechanical properties of the ECM.
“We found that dynamic bidirectional interactions take place between the leader cells and the ECM. Changes in ECM biomechanics induce protrusive behavior in cancer cells, which causes further changes in the ECM that becomes permissive for directional cancer cell movement. We have identified a set of genes whose expression is activated in response to increase in ECM stiffness; many of those genes regulate ECM remodeling and cellular invasive behavior.”
Antoine Khalil, UMCU
This work and much more is what Antoine and his colleagues in de Rooij’s team have achieved within the Mechano·Control project, and we know that there is more exciting and promising research to come until the project ends. For Antoine being a part of the Mechano·Control community was a great opportunity for his work because this project brings together various research fields at very different scales, “Throughout our meetings, conferences and communications we have established strong connections with the partners and learned so much from experts in the cell-ECM interaction field, at the computational, nanoscale and molecular and cellular levels” tells Antoine.
Samuel Pearson moved from Australia to Germany, where he works with research groups all over Europe with one common goal: to understand the factors influencing cancer progression. Samuel, Head of Applications in the “Dynamic Biomaterials” division of the Leibniz Institute for New Materials (INM), led by Prof. Aranzazu del Campo, is one of the Mechano·Control members. His work is focused on upscaling the production of polymer materials for 3D cell culture and bringing them towards commercialisation. Let’s take a closer look into his role within the consortium.
To understand how diseases like breast cancer develop, the response of breast cancer cells to different factors need to be studied one by one in isolation in 3D cultures. Samuel Pearson and his team produce synthetic hydrogels for 3D cell encapsulation with the possibility to adjust different parameters. These hydrogels mimic the properties of the natural breast cancer tissue in normal and disease conditions.
A particular interest of his group is the upscaling of the hydrogel precursors using affordable precursors and the design of stable, easy-to-handle compositions. This is the first step in technology transfer from the Mechano·Control project. With Mechano·Control partners, these materials are further developed into predictive breast cancer models.
Another crucial milestone for Samuel and his team is the processability of the hydrogels, which is related to the rate at which they are formed, i.e. the speed of the crosslinking reaction  during which cells are retained in a 3D matrix. The group has developed a patented crosslinking approach  based on thiol-methyl sulfone reactions which offer very convenient timescales for uniform encapsulation of cells. “In the future, we want to optimize our 3D cell encapsulation systems for automated high throughput methods that will enhance reproducibility and expand the applicability of our platform” explains Samuel. “The figure below shows how basal and luminal cells in breast cancer organoids organise in response to different adhesive ligands in the surrounding polymer network, which relies on consistent network properties” adds Samuel.
The materials developed by Samuel and his team play a crucial role in the Mechano·Control consortium. The high level of control and uniformity of the synthetic hydrogels allows to reduce the experimental variability in the biological studies, and this will help to uncover the individual factors that influence cancer progression. Moreover, this technology will not only be of great use for the consortium, but it also offers broad scientific and commercial potential for other 3D tissue culture models.
“We are optimising polymer structure and crosslinking chemistry to make hydrogels with very reliable properties. The focus right now is upscaling to allow high throughput studies and moving towards commercialisation”
The Mechano·Control project brings together an interdisciplinary research community with the aim to understand and control how cells transmit and detect mechanical forces, from molecules to organs, and all the way up to the organism level. This requires developing and integrating disparate technologies, and each research group involved in the project is an expert in a very specific field and scale: “Each group has its own deep expertise, but because we are working towards a common goal everyone is really motivated to understand the contributions from the other partners, which deepens everyone’s knowledge and experience.”
 A crosslink is a bond that links one polymer chain to another, forming a network. Hydrogels are crosslinked networks of hydrophilic polymers that are swollen with water and widely used for 3D cell culture. The crosslink density is a key parameter that determines the mechanical properties of the hydrogel, which can in turn influence the behaviour of encapsulated cells. In the research described above, covalent crosslinks are formed using a patented thiol-methyl sulfone crosslinking reaction.
 del Campo, A.; Farrukh, A.; Paez, J. I. Novel Hydrogels. WO2021001203A1, 2021, Priority DE102019117997A 2019-07-03, Filed 2020-06-23, Published 2021-01-07.