Nowadays diagnosis is largely enabled by the identification of molecular markers associated with the onset of a pathological state. Nevertheless, many diseases escape this paradigm, as the biochemical fingerprint of the aberrant cells do not differ significantly from healthy ones, hindering early diagnosis and reducing the impact of treatments. One prototypical example is Leukaemia, a type of cancer that kills more than 300,000 people in the world every year. The evolution of the disease happens as we get older, but there is now evidence that cells in our body progress towards a malignant phenotype many years before they can be identified with current diagnostic techniques. This proposal will exploit mechanobiology, a field of research that has progressed in the last 10 years, as a novel method to interrogate very early changes in cellular state, bringing it closer to medical use by combining advanced biomaterials, novel microscopy techniques and robotics. Mechanobiology has taught us that cells can feel and react to their mechanical environment. For example, cancer cells are softer than normal cells. However, reorganisation of their niche causes increased tissue stiffness. Here, we will use mechanical stimulation to interrogate cells potential to become cancer cells. Cell response to these external mechanical stimuli will reveal their potential to evolve from health to disease. We will focus on leukaemia, a cancer that originates in the bone marrow, as normal haematopoietic stem cells, which play the essential role to make our blood, start a malignant transformation giving rise to leukaemic stem cells. When this happens, we propose MSCs proliferate and produce new extracellular matrix, leading to a stiffer environment. It is believed that these changes in the environment trigger further expansion of leukaemic cells and vice versa. This project will develop an in vitro model of the bone marrow using soft hydrogels with defined mechanical and biochemical properties that host mesenchymal stem cells and hematopoietic (or leukaemic) stem cells. We will investigate how external mechanical stimulation of the model using nanoscale vibration of controlled frequency and amplitude can stimulate both cell populations to identify and maximise changes triggered by the presence of leukaemic cells. To monitor these mechanical changes in the bone marrow model we will develop Brillouin microscopy for use in a biological context. This technique is based on the propagation of acoustic waves in the system to characterise mechanical properties and will allow detailed mapping of stiffness of the bone marrow model as a function of time - importantly in a non-invasive way. Moreover, the level of mechanical stimulation will be dependent on the readout provided by Brillouin microscopy that will feed into a control system to alter the level of the mechanical vibrational stimulation imposed on the bone marrow model. We will first investigate the sensitivity of our technology to detect the presence of a single leukaemic cell in our bone marrow model and then, we will establish a proof of concept experiment with patient cells, through our clinical collaborators, that either have early signs of potential leukemic transformation or remain healthy as they age.

Nowadays diagnosis is largely enabled by the identification of molecular markers associated with the onset of a pathological state. Nevertheless, many diseases escape this paradigm, as the biochemical fingerprint of the aberrant cells do not differ significantly from healthy ones, hindering early diagnosis and reducing the impact of treatments. One prototypical example is Leukaemia, a type of cancer that kills more than 300,000 people in the world every year. The evolution of the disease happens as we get older, but there is now evidence that cells in our body progress towards a malignant phenotype many years before they can be identified with current diagnostic techniques. This proposal will exploit mechanobiology, a field of research that has progressed in the last 10 years, as a novel method to interrogate very early changes in cellular state, bringing it closer to medical use by combining advanced biomaterials, novel microscopy techniques and robotics. Mechanobiology has taught us that cells can feel and react to their mechanical environment. For example, cancer cells are softer than normal cells. However, reorganisation of their niche causes increased tissue stiffness. Here, we will use mechanical stimulation to interrogate cells potential to become cancer cells. Cell response to these external mechanical stimuli will reveal their potential to evolve from health to disease. We will focus on leukaemia, a cancer that originates in the bone marrow, as normal haematopoietic stem cells, which play the essential role of making our blood, start a malignant transformation giving rise to leukemic stem cells. We have demonstrated that healthy cells and pre-malignant/malignant cells respond differently to mechanical stimulation. This project will develop an in vitro model of the bone marrow using soft hydrogels with defined mechanical and biochemical properties that host mesenchymal stem cells and hematopoietic (or leukemic) stem cells, as are found together in the marrow. We will investigate how external mechanical stimulation of the model using nanoscale vibration of controlled frequency and amplitude discriminate between healthy vs diseased systems. To monitor these mechanical changes in the in vitro model we will use Brillouin microscopy in a biological context. This technique is based on the propagation of acoustic waves in the system to characterise mechanical properties and will allow detailed mapping of stiffness of the bone marrow model as a function of time - importantly in a non-invasive way. Moreover, the level of mechanical stimulation will be dependent on the readout provided by Brillouin microscopy that will feed into a control system to alter the level of the mechanical vibrational stimulation imposed on the bone marrow model. We will develop the technology to have a robust on-chip system that includes the bone marrow model and integrates mechanical stimulation. We will use the technology in two clinical applications: (1) to assess whether the technology can predict leukaemia which can be induced as an off-target effect of the treatment (chemotherapy/radiotherapy) of solid tumours and (2) to assess whether the technology can predict malignant transformations in heaematopoeitic stem cells that happes with age, eventally leading to leukaemia.

The bone marrow is a site of health and disease. In health, it produces all of the blood cells that we rely on to carry oxygen and protect us from infection. However, the stem cells that produce the blood and that reside in the marrow, the haematopoietic stem cells (HSCs), age and can tip over into disease states, such as developing leukaemia. Factors such as smoking and treatment of cancers elsewhere in the body (toxic effects of chemotherapy/radiotherapy) can accelerate ageing, and therefore, drive the transition to disease. Further, it forms a home to other cancer cells, that leave their original tumour and move, or metastasise, to the bone marrow. Once in the marrow, they can become dormant, hiding from chemotherapies and activating sometime later to form devastating bone cancers. The cues that wake cancer cells from dormancy are largely unknown. If models of the bone marrow that contain human cells and that can mimic key facets of the niche in the lab, such as blood regeneration, cancer evolution and dormancy, can be developed it would be a big help in the search for better cancer therapies. We are developing the materials and technologies required to meet this challenge. In this programme of research, we will tackle three biomedical challenges: 1) HSC regeneration. Bone marrow transplantation (more correctly HSC transplantation) is a one-donor, one-recipient therapy that can be curative for blood diseases such as leukaemia. It is limited as HSCs cannot be looked after well out of the body. Approaches to properly look after these precious cells in the lab could allow this key therapy to become a one-donor, multiple recipient treatment. Further, the ability to look after the cells in the lab would open up the potential for genetically modifying the cells to allow us to cure the cells and put them back into the patient, losing the need for patient immunosuppression. 2) Cancer evolution. As we get older, our cells collect mutations in their DNA and these mutations can be drivers of cancer. Lifestyle choices such as smoking, and side effects of treatments of other diseases can also add mutations to the cells. As blood cancers develop, the bone marrow changes its architecture to protect these diseased HSCs. Our 3D environments will allow us to better understand this marrow remodelling process and how drugs can target cancers in this more protective environment. The models will also allow us to study the potential toxicity of gene-edited HSCs to make sure they don't produce unwanted side effects or are not cancerous in themselves. 3) Dormancy. What triggers dormancy and activation from dormancy are poorly understood. By placing our 3D environments in a miniaturised format where we can connect other models that include infection and immune response, we can start to understand the factors involved in the activation of cancer cells from dormancy. Our vision is driven by materials and engineering, as the bone marrow niche is rich in structural and signalling biological materials (proteins). Therefore, we will establish three engineering challenges: (1) Cells can be controlled by the stiffness and viscous nature of materials (viscoelasticity). We will therefore develop synthetic-biological hybrid materials that can be manufactured to have reproducible physical properties and that have biological functionality. (2) We will develop these materials to interact with growth factors and bioactive metabolites, both of which are powerful controllers of cell behaviours. These materials will be used to assemble the HSC microenvironments in lab-on-chip (miniaturised) format to allow high-content drug and toxicity screening. (3) We will develop real-time systems to detect changes in cell behaviour, such as the transition from health to cancer using Raman and Brillouin microscopies. The use of animals in research provides poor predictivity. We will offer better than animal model alternatives.