The curry spice curcumin selectively inhibits cancer cells growth in vitro and in preclinical model of glioblastoma☆ Alfeu Zanotto-Filho a, ⁎, Elizandra Braganhol b , Maria Isabel Edelweiss c , Guilherme A.Behr a , Rafael Zanin b , Rafael Schröder a , André Simões-Pires a , Ana Maria Oliveira Battastini b , José Cláudio Fonseca Moreira a a Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brasil b Laboratório de Enzimologia, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brasil c Laboratório de Patologia, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brasil Received 14 December 2010; received in revised form 30 January 2011; accepted 24 February 2011 Abstract Previous studies suggested that curcumin is a potential agent against glioblastomas (GBMs). However, the in vivo efficacy of curcumin in gliomas rem established. In this work, we examined the mechanisms underlying apoptosis, selectivity, efficacy and safety of curcumin from in vitro (U138MG, U87, U C6 cell lines) and in vivo (C6 implants) models of GBM. In vitro,curcumin markedly inhibited proliferation and migration and induced cell death in liquid and soft agar models of GBM growth. Curcumin effects occurred irrespective of the p53 and PTEN mutational status of the cells. Interestingly, curcumin did n viability of primary astrocytes, suggesting that curcumin selectivity targeted transformed cells. In U138MG and C6 cells, curcumin decreased the constitutive activation ofPI3K/Akt and NFkappaB survivalpathways,down-regulated the antiapoptotic NFkappaB-regulated protein bcl-xl and induced mitochondrial dysfunction as a prelude to apoptosis. Cells developed an early G2/M cell cycle arrest followed by sub-G1 apoptosis and apoptotic bodies formation. Caspase-3 activation occurred in the p53-normal cell type C6, but not in the p53-mutant U138MG. Besides its apoptotic effect, curcumin also synergized with the chemotherapeutics cisplatin and doxorubicin to enhance GBM cells death. In C6-implanted rats, intraperitoneal curcumin (50 mg kg −1 d −1 ) decreased brain tumors in 9/11 (81.8%) animals against 0/11 (0%) in the vehicle-treated group. Importantly,no evidence oftissue (transaminases, creatinine and alkaline phosphatase), metabolic (cholesterol and glucose), oxidative or hematological toxicity was observed. In summary,data presented here suggest curcumin as a potential agent for therapy of GBMs. © 2012 Elsevier Inc. All rights reserved. Keywords: Curcumin; Glioblastoma; Apoptosis; In vitro; Preclinical 1. Introduction Glioblastoma (GBM) is an aggressive, invasive and difficult to treat primary brain tumor.Standard therapy includes surgical resection, external beam radiation and chemotherapy, with no known curative therapy [1,2]. A number of deregulated signaling cascades have been described in GBMs, including the nuclear factor kappa-B (NFkappaB), the phosphoinositide-3-kinase (PI3K/Akt) pathway and the Ras/MEK/ ERK mitogen-activated protein kinase pathway. Deregulation of these pathways is driven by mutation, amplification or overexpression of multiple genes such as PTEN, EGFr,PDGFR-a,p53 and mTOR [3–5]. Understanding these deregulated pathways has provided the basis for designing molecular targeted therapies as well as new combination therapies and drug delivery systems [6–8]. Despite the aforemen- tioned findings, median survival in GBM has remained approximately 1 year for decades [1,2]. Therefore, validation of new antiglioma drug may offer new therapeutic opportunities to patients. Curcumin (diferuloylmethane), a naturally occurring polyphenol derived from the root of the rhizome Curcuma longa, possesses anti- inflammatory,antioxidant and anticancer properties by inhibition of signaling pathways such as NFkappaB, PI3K/Akt and activator protein-1 (AP-1) [9]. Recently, curcumin entered into phase I clinical trials for the treatment of some high-risk cancers [10]. In GBMs, an emerging in-vitro-based literature [11–16] suggests that curcumin exerts antiglioma effects through enhancement of TRAIL-induced apoptosis [11],inhibition of metalloproteinase-9 expression [12,14] and induction of apoptosis in T98G and U87MG cell lines [13,15,16]. However,the apoptotic mechanisms, selectivity to transformed cells and principally the in vivo efficacy of curcumin in GBMs remain to be better studied. In this work, we examined the mechanisms underlying curcumin anti-GBM effects based on in vitro (C6, U138MG,U87 and U373 cell lines) and in vivo (C6 implants in rat brain) models of the disease.In vitro, we evaluated curcumin effects on proliferation, apoptosis and migration as well as antagonism with classical GBM survival pathways (PI3K/Akt and NFkappaB),selectivity to cancer Available online at www.sciencedirect.com Journal of Nutritional Biochemistry 23 (2012) 591 – 601 ☆ Conflict of interest statement: The authors report that there are no conflicts of interest. ⁎ Corresponding author. Depto.Bioquímica (ICBS-UFRGS), Rua Ramiro Barcelos, 2600/Anexo, CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil. Tel.: +55 51 3308 5578; fax: +55 51 3308 5535. E-mail address: alfeuzanotto@hotmail.com (A. Zanotto-Filho). 0955-2863/$ - see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.jnutbio.2011.02.015