Combined Supplementation of Vanadium and Fish Oil Suppresses Tumor Growth, Cell Proliferation and Induces Apoptosis in DMBA-Induced Rat Mammary Carcinogenesis Sangita Manna, Subhadeep Das, Mary Chatterjee, M. Janarthan, and Malay Chatterjee * Department of Pharmaceutical Technology, Jadavpur University, P.O. Box - 17028, Kolkata - 700 032, India ABSTRACT The anti-cancer activity of vanadium and fish oil has been shown in a large number of studies. This study was undertaken to analyze the combined effect of vanadium and fish oil on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis in female Sprague– Dawley rats. The whole experiment was divided into three parts: (1) DNA strand breaks study, (2) morphological analysis, and (3) histological and immunohistochemical study. Rats were treated with DMBA (0.5 mg/0.2 ml corn oil/100 g body weight) by a tail vein injection. Rats received vanadium (w/v) as ammonium monovanadate at a concentration of 0.5 ppm (4.27 mmol/L) in the drinking water and given ad libitum and/or fish oil (0.5 ml/day/rat) by oral gavage. Histology, morphology, DNA strand breaks, cell proliferation, and apoptosis of the mammary tissue were assessed in this study. Treatment with vanadium or fish oil alone significantly reduced the DNA strand breaks, palpable mammary tumors, tumor multiplicity, and cell proliferation but the maximum protection effect was found in the group that received both vanadium and fish oil and the combination treatment offered an additive effect ( P < 0.05). Furthermore, vanadium and fish oil significantly increased the TUNEL-positive apoptotic cells ( P < 0.05) but the increase was maximal with combination treatment and had an additive effect. These results affirm the benefits of administration of vanadium and fish oil in the prevention of rat mammary carcinogenesis which was associated with reduced DNA strand breaks, palpable mammary tumors and cell proliferation and increased TUNEL-positive apoptotic cells. J. Cell. Biochem. 112: 2327–2339, 2011. ß 2011 Wiley-Liss, Inc. KEY WORDS: APOPTOSIS; CELL PROLIFERATION; DNA DAMAGE; FISH OIL; VANADIUM L ong-chain polyunsaturated fatty acids (PUFAs) constitute an essential component in human nutrition. PUFAs, particularly those found in fish oils, have been known for their beneficial biological roles in human chronic diseases, in particular, carcino- genesis. There is epidemiological, clinical and experimental evidence that dietary fish oil containing n-3 poly-unsaturated fatty acids (n-3 PUFAs) including eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) protects against the development of breast, colorectal and prostate cancer (Hardman, 2002; Dommels et al., 2003; Kobayashi et al., 2004; Hilakivi-Clarke et al., 2005; Yi et al., 2007; Seti et al., 2009). Vanadium is an important trace element for different organisms. Vanadium is present in oils, fats, fruits, vegetables, cereals, liver, fish, spinach, oysters, shellfish, black pepper, and parsley. Studies from our laboratory have established vanadium as a novel biological regulator in assessing the physiological and biochemical state of animals in a dose related manner and have been shown to inhibit growth and metastasis of breast (Ray et al., 2007), colon (Samanta et al., 2008), and liver (Chakraborty et al., 2007a) cancer cells in vitro and in vivo. 7,12-dimethylbenz(a)anthracene (DMBA) mammary carcinogenesis in rats has been widely used in various mammary cancer chemopreventive studies. This model is preferred, because experimental conditions and requirements are well established and accepted (Russo et al., 1990). All living organisms are constantly exposed to environmental stresses that cause damage. Carcinogen-induced DNA damage has been implicated one of the early steps in chemical carcinogenesis. Over time and without adequate repair, DNA damage can lead to increased cancer incidence (Halliwell, 2002). Double-strand breaks (DSBs) in cells can be produced by genotoxic agents (ionizing radiation, oxidative damage, chemical agents), often through conversion of single-strand lesions into double-strand breaks during DNA replication in growing cells (Nishino and Morikawa, 2002). Journal of Cellular Biochemistry ARTICLE Journal of Cellular Biochemistry 112:2327–2339 (2011) 2327 Grant sponsor: University Grants Commission (Govt. of India), Special Assistance Programme, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India. *Correspondence to: Malay Chatterjee, Department of Pharmaceutical Technology, Jadavpur University, P.O. Box - 17028, Kolkata - 700 032, India. E-mail: mcbiochem@yahoo.com Received 3 January 2011; Accepted 13 April 2011  DOI 10.1002/jcb.23153  ß 2011 Wiley-Liss, Inc. Published online 18 April 2011 in Wiley Online Library (wileyonlinelibrary.com).