Three-Dimensional-Printed In Vitro Model of Colorectal Cancer with Immune Microenvironment and Reprogramming Capabilities

The tumor microenvironment (TME) plays a crucial role in determining tumor progression and influencing clinical therapy. The immunological microenvironment (IMM) is critical, as it directly influences tumor growth, metastasis, and response to treatment. The ability to simulate the interactions between tumor cells and immune cells in the TME in vitro can help investigate cancer growth and assess the effectiveness of therapies. In this study, in vitro 3D models of tumor tissues mimicking in vivo cell physiology were developed using tumor cells and macrophages. Colorectal cancer cells and macrophages were cocultured on 3D-printed Polycaprolactone (PCL) scaffolds to create an immune microenvironment that promoted cell adhesion, proliferation, and modulated polarization of macrophages. Immunofluorescence analysis revealed a 3.6-fold upregulation in the expression of CD68 and a 2.7-fold upregulation in the M2 macrophage marker CD163 in the 3D environment compared to the 2D culture. In regard to drug resistance tests, fewer dead cells were observed in the 3D printed model compared to the 2D environment. This 3D tumor immune tissue model exhibited excellent drug resistance and stable tumorigenic capacity in this study. In addition, the in vitro 3D tumor tissue model showed potential to simulate the tumorigenesis and development of tumors in vivo, where the tissue structure and malignant transformation of the tumor formed in this model showed similarity to tumor tissues obtained from patients. Taken together, these results indicate that this model can simulate the development of tumors, which offers a potential strategy for personalized cancer therapy and tumor immunity research.