About the tumor-dendritic cell reprogramming
At present, the vast majority of anti-cancer therapies are being tested using mouse models, the translational potential of which is quite limited at times due to inter-species differences. Additionally, despite the profound successes of cancer immunotherapies, many solid tumors are resistant to the current therapeutic strategies.
Recent studies have reported that overexpression of the transcription factors PU.1, IRF8, and BATF3 (PIB-vaccine, in short) in cancer cells induces their reprogramming into functional antigen-presenting type 1 conventional dendritic cells (cDC1s). This approach enhances the presentation of neoantigens by the reprogramed tumor-DC1s and promotes personalized anti-cancer immunity. Here, we have developed an innovative immunocompetent 3D tumor microtissue (TMT) model to evaluate the anti-tumoral potential of reprogramming tumors into cDC1s using PIB-vaccine as a novel therapeutic strategy.
Our TMT model mimics tumor microenvironment by co-aggregating tumor cells (T98G or A375 cell lines expressing GFP) with cancer-associated fibroblasts, which are subsequently co-cultured with healthy HLA-matched PBMCs in proprietary AKURAâ„¢ 384 well plates. To assess the ability of PIB-vaccine to reprogram tumor cells into cDC1s, TMTs were transduced with PIB-mCherry-encoding lentiviral particles at different multiplicities of infection (MOIs) and the expression of dendritic cell markers CD45 and HLA-DR were investigated by high-content confocal imaging.
We subsequently evaluated T cell activation, cytokine production, and tumor growth. Notably, we observed reduced growth of reprogrammed 3D TMTs compared to non-reprogrammed microtissues. Furthermore, pro-inflammatory mediators IFNγ, TNFα, and Granzyme B were significantly increased in the supernatants of reprogrammed 3D TMTs compared to non-reprogrammed conditions. Additionally, both results seemed to correlate with the percentage of reprogrammed tumor-cDC1s within the 3D TMT in an MOI-dependent manner, suggesting that in situ cDC1 reprogramming promotes T cell-mediated anti-tumor immunity.
In summary, using 3D co-cultures of human tumor, stromal, and immune cells in automation-compatible AKURAâ„¢ 384 well plates allowed us to demonstrate that PIB-vaccine induces the development of cDC1, promoting anti-tumor immunity. Our findings provide proof-of-principle for a novel cancer immunotherapy based on PIB-reprogramming and demonstrate the versatility of the AKURAâ„¢ platform to evaluate the efficacy of novel anti-cancer therapies.
Download our poster about the tumor-dendritic cell reprogramming
