Establishment of a patient-derived adrenocortical carcinoma 3D tumor construct platform for evaluation of therapeutic strategies

Abstract

Adrenocortical carcinoma (ACC) is an under-studied, aggressive cancer of the adrenal glands where surgical resection is currently the only effective curative option. However, after surgery the majority of patients experience tumor progression. The median overall survival of 12 months has not improved since approval of mitotane in 1970. The lack of effective therapies in ACC is partially due to the lack of preclinical models that accurately represent human ACC. Most attempts to generate ACC cell lines or animal models have been unsuccessful. The few existing models do not adequately reflect the oncogenic signaling pathways or intratumoral heterogeneity of human ACC. These limited model systems have hindered identification of drivers of tumor progression and immune escape mechanisms, thereby limiting development and testing of novel therapeutic approaches such as targeted therapies or immunotherapies. We developed human ACC patient-derived tumor constructs (PTCs) encapsulated in synthetic extracellular matrix. Our ACC PTCs exhibit hallmarks of ACC: proliferation, expression of key ACC biomarkers, such as SF1, and production of cortisol. We provide characterization in the form of immunofluorescence staining for ACC biomarkers, and confirmation of PTC proliferation and cortisol production - a hallmark of ACC. We then demonstrate the utility of ACC PTCs for evaluation of chemotherapies currently used clinically (mitotane) with and without experimental cocktails of etoposide, doxorubicin, and cisplatin, experimental targeted therapies, and cellular immunotherapies, primarily in the form of natural killer (NK) cell therapy. In particular, the latter - cellular immunotherapies - are cutting edge studies demonstrating potential to evaluate immunotherapies in ACC clinical scenarios. Together these data provide evidence that patient-derived ACC models can serve as an important tool for identification of future points of intervention and testing of novel therapeutic strategies to improve ACC clinical care.