1st Revision: Isobel Lester
Short Explainer Video
The fight against cancer feels everlasting. Although cancer is not as fatal as it once was, it is still a major cause of death worldwide. Current cancer treatments, namely chemotherapy and radiotherapy, are effective at killing cancer cells, but due to the similarity between cancerous cells and regular cells, treatments cannot differentiate between the two, leading to the death of healthy cells.
This results in its own set of respective problems for the individual. There also remains the issue of long dosing regimes and an inability to use these treatments at early stages of the disease. So, what promising alternatives exist?
What is the ‘Sugar Bomb’?
Scientists at the University of Edinburgh have been exploring the use of a ‘light activated drug’ that can kill cancerous cells without harming regular body cells. This drug, currently in its preliminary stages, has been colloquially coined the ‘sugar bomb’ due to the combination of the light-activated molecule with a chemical food compound (known as a metabolite) that the cancer cells need to function. Essentially, cancer cells are tricked into thinking this fatal drug is food due to the ‘sugar’ attached to the ‘bomb’, and once the 'sugar bomb' is inside the cancerous cell, it can be activated by light.
The drug then begins to ‘bomb’ the cancer cell by causing a series of chemical reaction that stop them from functioning. It is not hard to see why researchers are referring to this treatment as the ‘trojan horse’. It is important to note that the sugar bomb technique has been explored as a drug delivery system over a period of years with the components being trialed and refined to suit the target cells and avoid side effects caused by the death of human cells.
The light activated molecule is known as a photosensitizer - a group of molecules that are activated by specific wavelengths of light and use the energy absorbed to produce reactive oxygen species (ROS) that break down cell structures, causing cell death. Researchers at the University of Edinburgh are using a molecule known as SeNBD (a benzo selenadiazole sensitiser), which is reported to be the smallest photosensitizer to date (useful for crossing the cell’s natural defences). The SeNBD ‘scaffold’ can then be attached to a metabolite that the cancer cell needs to survive. A major advantage to this treatment is that different metabolites can be attached depending on what the cancer is partial to, such as protein, sugar, or fat.
How does it work?
It is helpful to look at cancer cells as greedy, sugar-crazed children trick-or-treating on Halloween night; these cells take up metabolites much faster than human cells. When the sugar bomb treatment is given to the patient these cancer cells snatch them up, refusing to share with the healthy cells. Once the treatment has been taken up by the cell, it lies there, waiting to be activated. Scientists are then able to shine a light to activate the drug to elicit the above-mentioned cell disruption mechanism to kill only the target cells.
Is this ready to be a widely used treatment?
These ‘metabolic warheads’ show incredible promise and have currently been trialled in zebrafish and human cells outside the body and on micro-tumours within the body - all with positive results. Further testing is needed to determine the safety and efficacy of the treatment for humans, as well as how this treatment can be implemented in clinical practice.
