The success of checkpoint inhibitors in improving cancer patient survival has demonstrated the therapeutic potential of immunotherapies. This advancement has reshaped oncology treatment and driven interest in harnessing immune modulation for a wider range of diseases. However, developing drugs that modulate immune activity presents unique challenges. A major limitation in preclinical research is the inefficiency of testing human-specific immune targets in animal models, which often fail to translate to clinical outcomes. Additionally, conventional in vitro systems lack immune reactivity due to their static and monocellular nature, limiting their predictive value. Advanced in vitro models can bridge this gap by offering increasingly relevant human physiology for testing drug efficacy and safety, along with absorption, distribution, metabolism, and excretion (ADME). In particular, immune-competent spheroids, organoids, and organs-on-a-chip (OoC) have emerged as promising tools. Although still in their infancy, these microphysiological systems (MPSs) have demonstrated the feasibility of replicating immune responses ex vivo, providing a new avenue for studying immune-targeting drugs with higher translational potential. In this review, we explore recent advances in immune-competent organoid and OoC models, highlighting their capabilities and limitations. We provide a perspective on their applications for cancer drug testing, discussing how these systems could refine preclinical immuno-oncology research and accelerate the development of next-generation immunotherapies.

Microphysiological systems (MPS) have enabled the introduction of more complex and relevant physiological elements into in vitro models, recreating intricate morphological features in three-dimensional environments with dynamic interactions lacking in conventional models. We implemented a renal cell carcinoma (RCC) co-culture model to recreate the cross-talk between healthy and malignant renal tissue. This model is based on the referenced multi-organ platform and consists of co-culturing a reconstructed renal proximal tubule with RCC spheroids. Custom-designed 3D-printed chambers were used to culture human renal epithelial proximal tubule cells (RPTEC) and facilitate their self-assembly into a renal tubule contained in a collagen type I matrix. Caki-1 RCC cells were embedded in an agar collagen matrix, subsequently forming cancer spheroids. Both collagen and agar/collagen gels were optimized to maintain their integrity during cyclic perfusion and withstand shear stress during a minimum culture period of 7 days. The gels also enable adequate nutrient supply and cell secretions. Moreover, the agar/collagen gels limit the overproliferation of RCC cells, ensuring relatively homogeneous spheroid size. The MPS chip microfluidic circuits comprise two independent culture chambers with the size of a standard 96-microplate well. The renal tubule and RCC gels populate separate chambers and share the same culture media, which is recirculated approximately twice per minute. Under these conditions, we observed upregulation of immune factor expression and secretion in the renal tubules (interleukin-8 and tumor necrosis factor-alpha). The renal tubules also shift their metabolic activity towards glycolysis under the influence of RCC. This novel approach demonstrates that a co-culture-based MPS can amplify the complexity of RCC in vitro and be employed to study the impact of cancer on non-tumor cells.