Towards the development of in vivo -mimicking tumor model for extensive study of tumorigenesis and establishment of personalized therapy, patient-derived primary tumor cells were employed in this work for three-dimensional (3D) bioprinting. Intrahepatic cholangiocarcinoma cells isolated from patient were bioprinted using a composite hydrogel system of gelatin-alginate-Matrigel ^TM into pre-designed grid architecture. ICC cells were observed to process a colony forming ability with high survival rate and active proliferation. Expression levels of tumor markers, cancer stem cell markers, matrix metalloproteinase protein, index of tumor fibrosis, index of liver function, and epithelial-mesenchymal transition regulatory proteins confirmed the development of the invasive and metastatic phenotype of the intrahepatic cholangiocarcinoma cells in the 3D printed tumor microenvironment. Similar results were obtained in anti-cancer drug resistance of the intrahepatic cholangiocarcinoma cells in the 3D bioprinted construct that demonstrated stem-like properties, which suggested the promising potential of current 3D printed tumor model in the development of personalized therapy, especially for discovery of more conducive targeted drugs.

Studying biological characteristics of tumors and evaluating the treatment effects require appropriate in vitro tumor models. However, the occurrence, progression, and migration of tumors involve spatiotemporal changes, cell–microenvironment and cell–cell interactions, and signal transmission in cells, which makes the construction of in vitro tumor models extremely challenging. In the past few years, advances in biomaterials and tissue engineering methods, especially development of the bioprinting technology, have paved the way for innovative platform technologies for in vitro cancer research. Bioprinting can accurately control the distribution of cells, active molecules, and biomaterials. Furthermore, this technology recapitulates the key characteristics of the tumor microenvironment and constructs in vitro tumor models with bionic structures and physiological systems. These models can be used as robust platforms to study tumor initiation, interaction with the microenvironment, angiogenesis, motility and invasion, as well as intra- and extravasation. Bioprinted tumor models can also be used for high-throughput drug screening and validation and provide the possibility for personalized cancer treatment research. This review describes the basic characteristics of the tumor and its microenvironment and focuses on the importance and relevance of bioprinting technology in the construction of tumor models. Research progress in the bioprinting of monocellular, multicellular, and personalized tumor models is discussed, and comprehensive application of bioprinting in preclinical drug screening and innovative therapy is reviewed. Finally, we offer our perspective on the shortcomings of the existing models and explore new technologies to outline the direction of future development and application prospects of next-generation tumor models.

An advanced in vitro cervical tumor model was established by 3D printing to study the epithelial-to-mesenchymal transition (EMT), which is a very important stage of dissemination of carcinoma leading to metastatic tumors. A HeLa/hydrogel grid construct composed of gelatin, alginate, Matrigel and HeLa cells was fabricated by forced extrusion in a layer-by-layer fashion. HeLa cells rapidly proliferated, formed spheroids and presented tumorigenic characteristic in the 3D-printed structure. With the supplement of TGF- β , aggregated HeLa cells started to disintegrate, and some of them changed into fibroblast-like spindle morphology, which indicated that EMT was induced. The down-regulation of epithelial marker E-cadherin, and up-regulation of mesenchymal markers such as snail, vimentin and N-cadherin were all observed in the 3D-printed model, and performed differently in 3D and 2D models. The TGF- β induced EMT was inhibited by the treatment of disulfiram and EMT pathway inhibitor C19 in a dose dependent manner, showing great potential for future studies of a therapeutic program towards cervical tumor metastasis.

Constructing in vitro drug models with a higher degree of bionics is considered to be an important approach to improve the effectiveness of existing drug screening models. 3D printing, co-culture and microfluidics are important methods that commonly used. This study combined the advantages of the three methods. A 3D co-culture microfluidic model with controllable hepatoma cluster size was constructed, and applied to pharmacodynamic tests of a new anti-CD147 monoclonal antibody, Metuzumab. In the phase of cell preparation, hepatoma cells in the new model were found to proliferate faster than common in vitro 3D models fabricated by cell printing only. The hepatoma cells were also found less affected by the increase of drug dosage in migration performance, proliferation performance and protein expression level in the new model compared with 2D models. These results are in line with those obtained from animal experiments and clinical trials of similar anti-CD147 antibody drugs. In view of the special mechanism of antibody drugs, a modified model was built by adding peripheral blood mononuclear cells into the new model as effector cells, porting traditional antibody-dependent cell-mediated cytotoxicity (ADCC) test to a co-culture 3D microfluidic microenvironment. The results showed that ADCC exhibited higher effectiveness in the microfluidic model than in 3D printing models under the same dose of drug treatment. The new model was proved constructive and it provided a valuable reference for complex in vitro hepatoma model studies and antibody drug screening researches.