An advanced non-animal model for cultivation and pharmacological perturbation of human tumor tissue
Question: Tumors in patients are appropriately described as pathological organs. In their in vivo environment these tumor organs are entangled in a complex interplay of the genotypically and phenotypically heterogeneous tumor cells and healthy host cell. This tumor milieu plays a key role in tumor development, progression and response to therapy. To preserve the complex in vivo tumor environment in a preclinical model we developed a device to culture slices of tumor in a perfusion air culture (PAC) system. We analyzed PAC cultivation and pharmacological perturbation of tumor tissue slices from patients. Methods: To facilitate continuous supply with nutrients, oxygen and drugs, we developed a perfusion air culture (PAC) system to culture tumor slices. The precision-cut tumor slices (250 mm to 300 mm thickness) are kept in-between two organotypic supports and fixed in a special chamber. The chamber is settled vertically inside of an air-permeable tube and connected with a syringe pump via a silicon tube allowing continuous perfusion of medium and drugs. Regular culture conditions are achieved by placing the PAC system in a standard CO2-incubator. In vivo therapy is simulated by adding of Cisplatin to the supplied culture medium. To investigate the drug effects common biomarkers (Ki67, gH2AX, HIF1a, GMNN, cleaved caspase-3) were analyzed in IHC staining. Results: Primary tumor tissue from high grade serous ovarian carcinoma was cut in 280 mm slices and cultured in the PAC system. Using de-cellularised porcine intestine as organotypic supports in the PAC system, we can culture the primary ovarian tumor tissue slices more than 7 days with good morphology. For pharmacological perturbation experiments culture medium was supplemented with 13 mM Cisplatin and constantly delivered to slices for 72 h, mimicking the in vivo situation in patients. Biomarkers showed the expected response to Cisplatin. Interestingly, tumor cells derived from slices can be further cultured as tumoroids in Matrigel, passaged and cryopreserved. Conclusion: The PAC system facilitates the cultivation and pharmacological perturbation of tumor tissue slices in the context of the complex tumor microenvironment. Due to the flexibility and adjustability of all culture conditions (e.g. oxygen, scaffolds, flow rate and drug supply) the PAC system closely resembles the in vivo situation and is suitable for individual testing of drug efficacy.