Updating ACC preclinical models: characterization of two new patient-derived cell lines

: AdrenoCortical Carcinoma (ACC) is an aggressive, rare and heterogenous malignancy, that requires diverse preclinical models. For this reason, the development of new cell lines is pivotal. Here we describe the development and characterization of two of them, SMAC-2 and SMAC-3, established from surgical specimens of ACC patients. The characterization included their mutational profiling, the evaluation of steroidogenic enzymes expression, secretory activity and the expression of steroid hormone receptors. The proliferative ability of these cells within a zebrafish embryos xenograft was also evaluated. SMAC-2 originated from a metastatic EDP-M-treated ACC in a female patient with hypercortisolism and hyperandrogenism, while SMAC-3 derived from a male patient with a mitotane-treated local recurrence, with no sign of hypercortisolism. TP53 was mutated in both lines. SMAC-2 cells were characterized by a pathogenic alteration on CTTNB1 gene and a deletion of CDKN2A gene, while SMAC-3 on MSH2 gene. Basal hormonal status analysis showed a cell model-specific fingerprint either in the hormonal secretion and gene and protein expression of steroid hormone receptors. SMAC-2 secreted high levels of cortisol. SMAC-3 secreted low basal level of cortisol. Mitotane displayed in both cell lines a low potency. Under the experimental conditions used, the xenografted area did not increase for both cell models. Experiments were carried out to study the stability of the two cell lines. SMAC-2 and SMAC-3 display unique molecular and functional features, expanding the repertoire of experimental ACC models and representing valuable tools for preclinical research alongside established cell lines.