Hindawi Publishing Corporation BioMed Research International Volume 2013, Article ID 791406, 11 pages http://dx.doi.org/10.1155/2013/791406 Research Article Synergistic Effect between Cisplatin and Sunitinib Malate on Human Urinary Bladder-Cancer Cell Lines Regina Arantes-Rodrigues, 1 Rosário Pinto-Leite, 2 Lio Fidalgo-Gonçalves, 3 Carlos Palmeira, 4,5 Lúcio Santos, 4,5 Aura Colaço, 6 and Paula Oliveira 1 1 Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr´ as-os-Montes and Alto Douro, Vila Real, 5001-801 Vila Real, Portugal 2 Genetic Service, Cytogenetic Laboratory, Hospital Center of Tr´ as-os-Montes and Alto Douro, 5000-508 Vila Real, Portugal 3 Department of Engineering, CMUTAD, University of Tr´ as-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal 4 Experimental Pathology and herapeutics Group, Portuguese Institute of Oncology, 4200-072 Porto, Portugal 5 Health School, University Fernando Pessoa, 4249-004 Porto, Portugal 6 Department of Veterinary Sciences, CECAV, University of Tr´ as-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal Correspondence should be addressed to Paula Oliveira; pamooliveira28@gmail.com Received 13 May 2013; Accepted 31 October 2013 Academic Editor: Joohun Ha Copyright © 2013 Regina Arantes-Rodrigues et al. his 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. he aim of this paper is to analyse sunitinib malate in vitro ability to enhance cisplatin cytotoxicity in T24, 5637, and HT1376 human urinary bladder-cancer cell lines. Cells were treated with cisplatin (3, 6, 13, and 18 M) and sunitinib malate (1, 2, 4, 6, and 20 M), either in isolation or combined, over the course of 72 hours. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, acridine orange, and monodansylcadaverine staining and low cytometry were performed. he combination index (CI) was calculated based on the Chou and Talalay method. In isolation, cisplatin and sunitinib malate statistically ( < 0.05) decrease cell viability in all cell lines in a dose-dependent manner, with the presence of autophagic vacuoles. A cell cycle arrest in early S-phase and in G 0 /G 1 -phase was also found ater exposure to cisplatin and sunitinib malate, in isolation, respectively. Treatment of urinary bladder-cancer cells with a combination of cisplatin and sunitinib malate showed a synergistic efect (CI <1). Autophagy and apoptosis studies showed a greater incidence when the combined treatment was put into use. his hints at the possibility of a new combined therapeutic approach. If conirmed in vivo, this conjugation may provide a means of new perspectives in muscle-invasive urinary bladder cancer treatment. 1. Introduction Urinary bladder cancer is a common malignancy of the urinary tract, being four times higher in men than in women [1]. Remarkable diferences can be found in its inci- dence worldwide, while being predominately higher in devel- oped countries such as North America and Western and Southern Europe [2]. At diagnosis, approximately 70% are nonmuscle invasive tumors [3], while the remaining 30% are muscle invasive and of these tumors about 10% of cases has a tendency to metastasize, with a poor prognosis [4]. he standard approach for muscle-invasive urinary bladder cancer treatment is based on a radical cystectomy with bilateral pelvic lymph node dissection. However, this treat- ment only ofers 5-year survival in about 68% of patients [5]. Cisplatin-based chemotherapy is widely used. Gemcitabine plus cisplatin exert comparable activity and a lower toxicity proile when compared to the methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) regimen [6]. However, chemotherapy courses continue to produce unsatisfactory rates of recurrence and death. hus, the simultaneously application of cisplatin with other anticancer drugs that target new signalling pathways has been investigated [7]. Sunitinib malate is an orally bioavailable molecule with the ability to block the intracellular tyrosine kinase domain of tyrosine kinase receptors. It is also responsible for inhibition