Development of a human 3D tumor microenvironment-on-chip model for personalized drug testing on a pancreatic adenocarcinoma

Currently, pancreatic adenocarcinoma belongs to the tumor types with the lowest five-year survival rate. A key reason for the failure of new drug candidates is the lack of predictive cell and animal models in preclinical research. In addition to their 3D architecture, pancreatic tumors are also characterized by great cellular heterogeneity. The tumor microenvironment is highly fibrotic and highly inflammatory and contributes significantly to tumor progression and the development of resistance to existing therapies. The GOAL of this project was to establish a new microfluidically supported human 3D PDAC co-culture model platform with integrated blood vessel cell components in a biochip to identify new personalized therapeutic approaches. The 3D co-cultures are composed of pancreatic tumor cells and stellate cells obtained from the primary tumor.
The development of the PDAC model was carried out on a biochip with a special, integrated membrane. This membrane contains microcavities with a diameter of 800m to immobilize complex tissue models such as tumor spheroids under microfluidic culture conditions. A membrane in a biochip chamber can hold up to 25 spheroids in parallel. In addition, such a biochip chamber contains a second flat membrane above it for the establishment of blood vessel structures. Two culture chambers are provided on one biochip, allowing up to 50 PDAC spheroids to be examined in parallel.

Following the initial conceptualisation and implementation of the chip design, work began on integrating the PDAC spheroids into the new chip. During this process, the dimensions and routing of the channels, as well as the culture time window for the spheroids prior to their introduction into the biochip, were tested. A culture time of 4 days prior to transfer into the biochip proved to be ideal. In the next step, the methodology for introducing the tissue spheroids was optimised to ensure non-destructive introduction and maximum occupancy of all microcavities with spheroids. A method was ultimately developed that achieved an occupancy rate of 80–90% (Fig. 2).

In the next step, the model was tested under 72-hour perfusion. It was observed that the PDAC spheroids remained stable and viable and benefited from perfusion with cell culture medium. This time frame is generally recognised for assessing the acute cytotoxic efficacy of therapeutics. Furthermore, as part of the project, vascularisation of the new biochip-based PDAC model was successfully established. Through intensive evaluation of various culture parameters—such as pore size in the membrane, membrane coatings with connective tissue components, seeding densities of blood vessel cells, and perfusion rates during microfluidic culture—the optimal combination was successfully identified. This has thus created an excellent foundation for further investigation of the topics of immune cell perfusion and dynamic drug delivery, similar to conditions in patients. Through its project funding, the SET Foundation helped lay a successful foundation for future developments. Further research funding has already been successfully secured using the data generated.