Vitamin C may hold the key to improve efficacy of dendritic cell-derived anticancer cell therapies

Since the onset of anticancer cell therapies, those that use living cells to find and eliminate tumors, many types of immune cells have been used. The best-known cell therapies use lymphocytes, as in the highly successful CAR-T therapies. Recently, dendritic cells have attracted the scientists' attention thanks to its ability to uptake and present antigens (small parts of a pathogen or a cancer cell) to the T-lymphocytes and induce an antigen-specific potent immune activation. On this regard, loading dendritic cells with specific antigens to create immune memory constitute the so-called DC-vaccines.

To study dendritic cells in the lab, researchers differentiate them from monocytes (also an immune cell) using a particular set of molecular signaling. This differentiation is accomplished through a complex set of gene activation processes in the nucleus, mostly thanks to the activity of the chromatin remodeling machinery spearheaded by the TET family of demethylases, proteins that act upon the DNA epigenetic marks.

Vitamin C was known to interact with several TET proteins to enhance its activity, but the specific mechanism was still poorly understood in human cells. In a recent publication in the journal Nucleic Acids Research, a team lead by Dr. Esteban Ballestar hypothesized that treating monocytes in vitro while differentiating into dendritic cells, would help the resulting cells be more mature and active.

The results obtained by Octavio Morante-Palacios, first author of the publication, José Luis Sardina (also from the Josep Carreras Leukaemia Research Institute) and Eva Martínez-Cáceres, Head of Immunology of the Germans Trias i Pujol Research Institute, 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. Also, vitamin C increases the communication of the resulting dendritic cells with other components of the immune system and stimulates the proliferation of antigen-specific T cells.

Actually, 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, showing the superiority of DC-vaccines treated with vitamin C.

Overall, these new findings support the hypothesis that treating monocyte-derived dendritic cells with vitamin C may help generate DC-vaccines with higher performance. 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.