Liposomal polychemotherapy improves adrenocortical carcinoma treatment in a preclinical rodent model

Abstract

Owing to high relapse rates and early metastatic spread, prognosis in adrenocortical carcinoma (ACC) patients remains poor, highlighting the importance of developing new treatment alternatives for them. Recently, polychemotherapy regimens including etoposide, doxorubicin, and cisplatin together with mitotane (EDP-M) have been defined as the standard treatment for late-stage disease patients. Nevertheless, the administration of conventional cytostatic drugs is associated with severe and dose-limiting side effects. In an attempt to optimize existing clinical treatment regimens, in this study, we investigated the therapeutic efficacy of EDP-M in comparison with that of a paclitaxel-modified scheme (paclitaxel, doxorubicin, cisplatin plus mitotane (PDP-M)) in preclinical in vitro and in vivo models. In addition, based on an extraordinary uptake phenomenon of liposomes in ACC cells, we further evaluated liposomal variants of these protocols (etoposide, liposomal doxorubicin, liposomal cisplatin plus mitotane (LEDP-M) and nab-paclitaxel, liposomal doxorubicin, liposomal cisplatin plus mitotane (LPDP-M)). In vitro, PDP-M was more potent in the induction of apoptosis and inhibition of cell viability as well as cell proliferation than EDP-M. Following the administration of a single therapeutic cycle, we further demonstrated that LEDP-M and LPDP-M exerted significant antitumoral effects in vivo, which were not as evident upon EDP-M and PDP-M treatments. These results were confirmed in a long-term experiment, in which the highest and sustained antitumoral effects were observed for LEDP-M. In summary, liposomal cytostatic substances could represent a promising option that deserves testing in appropriate clinical protocols for the treatment of ACC patients.