A novel copper complex induces ROS generation in doxorubicin resistant Ehrlich ascitis carcinoma cells and increases activity of antioxidant enzymes in vital organs in vivo
1 Department of Environmental Carcinogenesis and Toxicology, Chittaranjan National Cancer Institute (CNCI), 37 S. P. Mukherjee Road, Calcutta-700026, India
2 Department of Immunology, Indian Institute of Chemical Biology, Calcutta– 700 032, India
3 Department of Clinical Biochemistry, Hospital Unit, CNCI, 37 S. P. Mukherjee Road, Calcutta-700026, India
4 Department of In-vitro Carcinogenesis and Cellular Chemotherapy, CNCI, 37 S. P. Mukherjee Road, Calcutta-700026, India
5 German Cancer Research Center, Heidelberg, Germany
BMC Cancer 2006, 6:267 doi:10.1186/1471-2407-6-267Published: 15 November 2006
In search of a suitable GSH-depleting agent, a novel copper complex viz., copper N-(2-hydroxyacetophenone) glycinate (CuNG) has been synthesized, which was initially found to be a potential resistance modifying agent and later found to be an immunomodulator in mice model in different doses. The objective of the present work was to decipher the effect of CuNG on reactive oxygen species (ROS) generation and antioxidant enzymes in normal and doxorubicin-resistant Ehrlich ascites carcinoma (EAC/Dox)-bearing Swiss albino mice.
The effect of CuNG has been studied on ROS generation, multidrug resistance-associated protein1 (MRP1) expression and on activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx).
CuNG increased ROS generation and reduced MRP1 expression in EAC/Dox cells while only temporarily depleted glutathione (GSH) within 2 h in heart, kidney, liver and lung of EAC/Dox bearing mice, which were restored within 24 h. The level of liver Cu was observed to be inversely proportional to the level of GSH. Moreover, CuNG modulated SOD, CAT and GPx in different organs and thereby reduced oxidative stress. Thus nontoxic dose of CuNG may be utilized to reduce MRP1 expression and thus sensitize EAC/Dox cells to standard chemotherapy. Moreover, CuNG modulated SOD, CAT and and GPx activities to reduce oxidative stress in some vital organs of EAC/Dox bearing mice. CuNG treatment also helped to recover liver and renal function in EAC/Dox bearing mice.
Based on our studies, we conclude that CuNG may be a promising candidate to sensitize drug resistant cancers in the clinic.