(175aw) Hydrogel Facilitated Co-Culture Tumor Microenvironment

Skin cancers account for more than 1.5 million new cases every year. Cancer growth and progression have been linked with tumor microenvironment, which necessitates a thorough understanding of interactions between the host immune system and the tumor, the function of the tumor microenvironment and tumor heterogeneity. In addition to cancer cells, immune cells including neutrophils, macrophages, and dendritic cells also form an integral part of the microenvironment. Although immunocompetent models with mouse cancer cells and immunocompromised models with human cells, including PDX models, are used, extensive use of animals, cost, and incapable of changing genetic composition.

Development of in vitro tumor models that mimic in vivo phenotype can provide insights on the biophysical and biochemical signaling aspects responsible for tumor growth, proliferation, migration, invasion, dormancy, angiogenesis, and drug delivery can facilitate fundamental advances and accelerate drug screening.

Here, we report developed a co-culture organoid system comprising of murine (B16F10 OVA) / human (NRAS mutant A375) melanoma cell lines and J774-Dual mouse macrophage reporter cell line on tissue culture plastic as well as on amikagel, a hydrogel formed by crosslinking between amikacin hydrate and polyethylene glycol diglycidyl ether. Our studies demonstrated that modulation of PEGDE content can result in higher mechanical stiffness of the gel causing lower adhesivity of the cells to the Amikagel. Moreover, we have shown that the chemo-mechanical engineering of Amikagel helps in generating a tumor suppressive microenvironment. We have seen that in presence of Amikagel, a damepned M1 environment is generated even though J774-Dual mouse macrophages are stimulated by LPS. We have demonstrated that macrophages stimulated by LPS, depicting a M1 phenotype becomes dormant when cocultured with cancer cells on tissue culture plastic (p<0.005) and on amikagel (p<0.0001), verified by reporter assay as well as cytokine release assays (TNF-α, IL-6, IL-10, IL-1β). Restimulation studies were performed with poly I:C, an APE1 inhibitor drug-E3330, hyaluronic acid derived polymers to get back the pro-inflammation response, but our studies showed no successful restimulation effects. Taken together our results demonstrate that melanoma-macrophage co-culture organoids demonstrate immune suppressive characterisitcs and that stimulation using THESE ligands can help activate macrophages to a pro-inflammatory phenotype. These platforms can be used for parallel screening of libraries for immunomodulatory activity.