Your cells die every day. Don’t worry, your body is protecting itself. In a process known as apoptosis or programmed cell death, cells that are no longer needed commit suicide. Some cells are only required for a short time, they may be infected by a virus or develop harmful cancerous mutations. Cell death is also an essential part of development from an embryo. For example, mouse paws begin as spade-like structures and only form the individual digits as the cells in between die. During apoptosis the cells fragment into smaller apoptotic bodies, and their cell surface is flipped open to display lipid molecules called phosphatidylserines, which act as an ‘eat me’ signal to recruit cells called macrophages to engulf them, before their contents spill out and damage the surrounding tissue. This is a process known as efferocytosis.
However cell death is not always so orderly. Some cells suffer premature death known as necrosis, where they burst open for various reasons such as infection, physical trauma or extreme temperatures. As the cell’s contents are released into the open, an inflammatory response is triggered. Studies are ongoing to establish the many mechanisms by which this process occurs. For example, it is known that proteins on the surface of immune cells, called pattern recognition receptors or PRRs, detect the material released by dying cells, and trigger the expression of genes leading to the release of inflammatory substances. When an infection occurs, the immune response is usually short-lived as it rapidly kills the infection. However, when cell necrosis and subsequent inflammation occurs over a longer period, the substances released by macrophages – that have migrated in to engulf the dying cells – can damage the surrounding tissue, resulting in a build-up of dead cells.
For the last 10 years I have been a clinical scientist in genetics working across various London NHS Trusts. Whilst I loved diagnostics, last year I left my job to complete my PhD. I worked in a part of life sciences called cytogenetics. This meant when a patient was diagnosed with blood cancer, I would analyse their chromosomes – the structures into which DNA is organised – from their blood or bone marrow to look for specific abnormalities. For some patients, this can lead to a definitive diagnosis. For others a refined prognosis, and in some, it’s simply a way of monitoring how well the patient’s leukaemia is responding to their treatment.
Blood cancer can be very straightforward to diagnose and it was perfectly possible to provide genetic confirmation of a blood cancer diagnosis in a matter of hours. For example, in patients with chronic myeloid leukaemia (CML), I would find a particular abnormality called a Philadelphia translocation between chromosomes 9 and 22. Finding this translocation means a patient will benefit from a targeted therapy – called a tyrosine kinase inhibitor (TKI) – which reverses the effect of the translocation with relatively few side effects. TKIs are a tablet taken once or twice a day at home. Compared to chemotherapy, TKIs have revolutionised the treatment and outcomes of CML, which has been life-changing for CML patients. It was always satisfying to call the referring clinician and let them know their patient had a Philadelphia translocation because I knew that would set the wheels in motion for a TKI to be prescribed. Ultimately I knew I had made a difference to a patient on those days. (more…)
In this post, four Imperial researchers write about the different ways in which Leuka has supported their work at the College.
Leuka is a charity that supports life-saving research into the causes and treatment of leukaemia and other blood cancers. Funding from dedicated charities such as Leuka provides an important source of support which enables high-quality research programmes here at Imperial to develop and progress. (more…)