Design, synthesis and antitumor evaluation of novel thalidomide dithiocarbamate and dithioate analogs against Ehrlich ascites carcinoma-induced solid tumor in Swiss albino mice

A series of 16 novel thalidomide sulfur analogs containing one and two sulfur atoms 2 and 4-18, respectively, were designed and synthesized. These compounds were screened for in vitro antitumor activity against Ehrlich ascites carcinoma (EAC) cell line and exhibited potent cytotoxic activity. On the bases of the obtained results for in vitro cytotoxic activity, thalidomide sulfur analogs containing two sulfur atoms 8, 9, 13 and 14 were selected and tested in vivo against EAC-induced solid tumor in female mice compared to thalidomide 1 as well as its analog 2 and exhibited a highly significant reduction in tumor volume (TV). Results illustrated the antioxidative activity of these compounds as the level of hepatic lipid peroxidation decreased and levels of antioxidant enzymes like superoxide dismutase (SOD) and catalase were elevated. The histopathological investigations revealed that thalidomide sulfur analogs 2, 8, 9, 13 and 14 have antimitotic, apoptotic and necrotic activities against solid tumor. These compounds lead to increase of Fas-L expression. The immunohistochemical studies showed a decrease in Ki67 and vascular endothelial growth factor (VEGF) staining in tumor cells from treated-animals when compared with non-treated groups, which suggests an inhibition of tumor proliferation rate and angiogenic process associated with tumor growth. Compounds 9 and 13 were the most potent compounds in tumor necrosis without liver necrosis. At the same time, treatment with compound 9 resulted in liver degeneration.