Research Article A Carotenoid Extract from a Southern Italian Cultivar of Pumpkin Triggers Nonprotective Autophagy in Malignant Cells Maria Russo, 1 Stefania Moccia, 1 Stefania Bilotto, 1 Carmela Spagnuolo, 1 Miriana Durante, 2 Marcello Salvatore Lenucci, 3 Giovanni Mita, 2 Maria Grazia Volpe, 1 Rita Patrizia Aquino, 4 and Gian Luigi Russo 1 1 Istituto di Scienze dell’Alimentazione, Consiglio Nazionale delle Ricerche, 83100 Avellino, Italy 2 Istituto di Scienze delle Produzioni Alimentari, Consiglio Nazionale delle Ricerche, 73100 Lecce, Italy 3 Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, 73100 Lecce, Italy 4 Dipartimento di Farmacia, Università di Salerno, Fisciano, Italy Correspondence should be addressed to Gian Luigi Russo; glrusso@isa.cnr.it Maria Russo, Stefania Moccia, and Stefania Bilotto equally contributed to the data presented. Received 11 June 2017; Revised 10 October 2017; Accepted 24 October 2017; Published 21 December 2017 Academic Editor: Kota V. Ramana Copyright © 2017 Maria Russo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Carotenoids, including β-carotene, lycopene, and derivatives, such as retinoic acid, have been studied for their significant antiproliferative and differentiating activity on cancer cells in experimental models and in clinics. We are presenting here data on the mechanism of action of a carotenoid-enriched extract obtained from the pumpkin Cucurbita moschata, variety “long of Naples,” on two malignant human cell lines, Caco-2 and SAOs, derived from a colon adenocarcinoma and an osteosarcoma, respectively. The carotenoid extract has been obtained from pumpkin pulp and seeds by supercritical CO 2 extraction and employed to prepare oil-in-water nanoemulsions. The nanoemulsions, applied at a final carotenoid concentration of 200–400 μg/ml, were not cytotoxic, but induced a delay in cell growth of about 40% in both SAOs and Caco-2 cell lines. This effect was associated with the activation of a “nonprotective” form of autophagy and, in SAOs cells, to the induction of cell differentiation via a mechanism that involved AMPK activation. Our data suggest the presence of a pool of bioactive compounds in the carotenoid-enriched extract, acting additively, or synergistically, to delay cell growth in cancer cells. 1. Introduction In the last two decades, the anticancer properties of phyto- chemicals raised the interest of many scientists, although pre- clinical and clinical studies often generated contradictory results. Excellent reviews have been published on this topic [1–4]. Among these, a recent meta-analysis of prospective studies suggested a positive correlation between dietary intake of phytochemicals (800–600 mg/die) and reduced risk of can- cer, cardiovascular diseases, and all causes of mortality [2]. Carotenoids represent one of the most largely studied class of phytochemicals, since their biological activities have been asso- ciated with positive outcomes in terms of human health [5]. Carotenoids are yellow-orange pigments widespread in nature, responsible for the coloration of different plant organs (e.g., roots, fruits, and flowers), but they are also abundantly present in marine invertebrates and microorganisms [6]. Carotenoids include about 600 isoprenoid compounds con- taining up to 15 conjugated double bonds divided into the two major groups of carotenes and xanthophylls; the former are pure hydrocarbons such as β-carotene, while the latter include their oxygenated derivatives, such as zeaxanthin. About 50 carotenoids are present in the human diet, but only 20 have been identified in the human plasma, among these, the most represented are β-carotene and α-carotene, lyco- pene, and cryptoxanthin [7, 8]. In human tissues, carotenoids Hindawi Oxidative Medicine and Cellular Longevity Volume 2017, Article ID 7468538, 15 pages https://doi.org/10.1155/2017/7468538