New research published in Nucleic Acids Research has shown that vitamin C improves the immunogenic properties of dendritic cells, activating genes involved in the immune response. This discovery could help the development of potent new dendritic cell-based immunotherapies.
Since the onset of anticancer cell therapies, many types of immune cells have been used. The best-known of these cell therapies use lymphocytes, as in the highly successful CAR-T therapies. Recently, researchers have to turned to dendritic cells, known as the ‘master regulators of the immune system‘, for their ability to uptake and present antigens to the T-lymphocytes and induce an antigen-specific potent immune activation. This approach entails loading dendritic cells with specific antigens to create immune memory to make dendritic cell (DC)-vaccines.
To study dendritic cells in the lab, researchers differentiate them from monocytes using a particular set of molecular signalling. This differentiation is accomplished through a complex set of gene activation processes in the nucleus, mostly thanks to the activity of the chromatin remodelling machinery spearheaded by the TET family of demethylases, proteins that act upon the DNA epigenetic marks.
Vitamin C was already known to interact with several TET proteins to enhance its activity, but the specific mechanism was still poorly understood in human cells. In this study, a team lead by Dr Esteban Ballestar hypothesised that treating monocytes in vitro while differentiating into dendritic cells, would help the resulting cells be more mature and active.
The results obtained show that vitamin C treatment triggers an extensive demethylation at NF- kB/p65 binding sites compared with non-treated cells, promoting the activity of genes involved in antigen presentation and immune response activation. Vitamin C was also found to increase the communication of the resulting dendritic cells with other components of the immune system and stimulates the proliferation of antigen-specific T cells.
The researchers proved that vitamin C-stimulated dendritic cells loaded with antigens specific for the SARS-CoV-2 virus were able to activate T cells in vitro more efficiently than non-treated cells.
Overall, these new findings support the hypothesis that treating monocyte-derived dendritic cells with vitamin C may help generate more effective DC-vaccines. After consolidating these results in preclinical models and, hopefully, in clinical trials, a new generation of cell therapies based on dendritic cells may be used in the clinic to fight cancer more efficiently.
