One of the key mechanisms that cancer cells use to avoid being detected by the patient’s immune system is to build a micro-environment that inhibits immune system activity. Specifically, the cancer cells stimulate specific immune cells to directly stop their attack on the cancer cells. Thus, in a very large proportion of cancer patients, these immunosuppressant cells have eliminated the immune system’s ability to recognise and activate an immunological attack on cancer cells.
A research team from DTU Health Tech led by Professor Thomas L. Andresen has recently published research findings that appear to help solve this problem. For many years, researchers have worked on designing systems for optimized drug delivery systems. And these advanced systems have gradually been optimized to such an extent that they can target cancer cells with great accuracy as well as target immune cells with specific functions, both in cancer and inflammatory diseases.
In the latest issue of Science Advances, the research team presents a so-called liposome-based drug delivery system for chemo-immunotherapy. Liposomes are a kind of nano-carrier that contain concentrated drugs and are able to bring this drug effectively to the target.
The liposome system is able to ‘jump’ from the bloodstream into cancerous tumours. This increases the drug concentration in the cancerous tumour more than 100 times compared to standard treatment in the evaluated cancer models. This may sound impressive in itself, but the most important characteristic of the liposome design is a unique ability to release the active drug after arrival in the cancerous tumour.
In cancerous tumours, specific enzymes lead to a splitting of surface components on the liposomes, so they now transfer their cytotoxic drug to the cancer cells and the immunosuppressant cells, which are then combated effectively. Together, these effects restart the immune system and allow it to initiate a coordinated cancer-specific attack.
“Our research indicates that well-designed liposome systems for chemo-immunotherapy may be a potent supplement to clinical immunotherapy in the future,” says Thomas L. Andresen.
The effect of this technology and its synergetic effect with immunotherapy has been validated in the study across a number of experimental cancer models. A very important observation is that technology causes a sharp increase in the level of the immune effector cells, which can fight cancer cells very specifically. This is particularly interesting as a high prevalence of these cells increases the chance of responding to clinically approved immunotherapy.
Although immunotherapy is still in embryo, impressive effects have been observed in some patients. However, the full curative effect is still seen in very few. But the newly developed liposome system specifically increases the level of these important cells and therefore has the potential to improve the effectiveness of clinical immunotherapy.
The study thus raises hope that new drug delivery systems could lead to more cancer patients being cured with immunotherapy.