There is an emerging new method in cancer treatment

Following the current standard chemotherapy or antibody-based therapeutics, produced by cell culture, living cells could be the next generation of cancer medicine. The human immune system can and does efficiently fight against tumour cells with cells like T cells or natural killer (NK) cells. These cells are circulating in the bloodstream and when they are signalled to go to battle against some malignant entities, they rapidly expand in number. So, logical question: why do not use them for this purpose, deliberately? The concept of cell therapy is exactly this, immune cells are used against cancer.

But, how to win this battle? The immune system is in need of some support because the number of “anti-tumour cells” naturally available is generally not sufficient for victory. Therefore, immune cells are artificially increased in number and used as part of a hospital treatment to effectively fight against tumours. To achieve this, cells have to be isolated from the bloodstream and cultured in-vitro and then administered into the patient. In contrast to the often-applied chemotherapy, this is a safe, direct, efficient and very specific method to treat tumours.

The efficiency of the treatment strongly depends on the cytotoxic activity of the immune cells, which is their potential to kill a malignant cell. This potency is determined by the genome of the cells themselves and the handling of them in general such as the culturing medium, conditions and methods.

The task of the engineers is to understand the process of cell expansion because the cells have to grow different from their natural environment but in the amount and quality needed for the treatment. Contrary to cell culture that is used for protein production, in this case the cells themselves are the product, which means they cannot be genetically tuned or selected because the patient’s system has to accept them.

Therefore, there is an even higher demand on the culture itself. If we look back on the evolution of mAb production during the past 20 years, we can see a massive improvement in every aspect of technology including cell culture. If we take antibody titre as an example, the then normal 1 g/L is nowadays close to 10 g/L and let’s note here: the quality related aspects also improved. Immune cell expansion is a relatively novel field, which means cell expansion methods and techniques are not as widely understood as nowadays’ standard cell culture, not talking about the analytics and instrumentation. Scientists and engineers are about to immerse themselves into this field that will be followed by the vendors to supply their requests. This evolution will eventually lead to platform technologies.

In our vision, cell therapy and more precisely the part of cell expansion is facing this technological advancement

But to get there, a lot of work is needed to be done. Bioprocess engineers have to technologize cell expansion and the related fields. Although defined media are used but the usage of human serum in the culturing medium is so far inevitable to achieve the desired cytotoxicity. Furthermore, cells are extremely sensitive to culture conditions therefore their culture has to be carried out with the outmost control possible and the culturing methods have to be advanced to keep up with the demands of the therapeutic needs. In our opinion, the inefficient, hard to control static cultures need to be replaced with dynamic cultures that offer better space-time yield, more control options and they provide an environment that mimics the conditions of human blood, the natural location of these cells, closer than the flat bottom of a flask.

With this mindset, our recent review article covers the application of bioreactors for cell expansion. We compared different types of reactors and gave an overview of their advantages and disadvantages based on the reported usage in the literature. Check it out yourself and learn about the potential of bioreactors for cell therapy, of course open access.