During brain metastasis, tumor cells interact with the surrounding stroma, including neurons and astrocytes, to create a tumor-promoting microenvironment. However, the molecular and cellular factors driving tumor-neural stroma interactions remain unclear. Here, we developed a co-culture model of metastatic melanoma by combining metastatic melanoma cells with dissociated human iPSC-derived cerebral organoids, consisting of neurons and astrocytes, in a microfluidic device. We cultured these astrocytes and neurons in a 3D hydrogel that contained a domain with metastatic melanoma cells. This approach generated a spatially organized co-culture system with no physical boundary between the tumor and stromal compartments. Then, we leveraged several imaging modalities to study tumor-stroma interactions and changes in the microenvironment. Using non-destructive, luminescence-based methods, we spatially resolved changes in cell viability, metabolite concentration, and other biochemical parameters. We also used luminescence to analyze the effect of radionuclides on tumor cell viability and used PET imaging to monitor their diffusion across the system.

Background: Adoptive cell therapies are emerging as a promising therapeutic option against hematological and solid malignancies. Memory-like natural killer (mlNK) cells are a specific subtype of NK cells generated after cytokine preactivation that have shown enhanced in vivo persistence after infusion into patients, an issue that has hindered traditional NK cell immunotherapy. However, the quality and variability of mlNK cell products remains poorly defined. Methods: In this study, we evaluated heterogeneity across critical functional and molecular aspects of mlNK cells generated from independent donors, including mlNK cytotoxicity, cluster formation, motility, mitochondria morphology, and gene expression. Results: We observed a correlation between changes in gene expression associated with glycolysis and key NK cell functions such as cytotoxicity and motility. For further characterization, we blocked glycolysis and oxidative phosphorylation (OXPHOS) and observed an impaired mlNK functional response, suggesting the importance of metabolism. Conclusions: Our findings provide insights into discriminating between mlNK cell products and how the predictive markers can identify optimal mlNK cell products for adoptive cell therapy of cancer.