Studies On Synthesis And Anti-angiogenesis Activity Of Tanshinone â…¡A Derivatives And Biotinylated Fumagillin

Tumor growth, invasion and metastasis are strongly dependent on tumor angiogenesis, this point of view was first put forward in 1971 by Folkman. Previous results from basic research and clinical study have confirmed that over-activated tumor angiogenesis plays a key role in many solid tumor growth and metastasis through supplying the tumor tissues with oxygen and nutrition. Therefore, blockade of tumor angiogenesis has emerged as an effective way and novel therapies to suppress tumor growth and metastasis.TanshinoneⅡA is one of the main anti-tumor compounds isolated from Salvia miltiorrhiza, a traditional Chinese medicine. Previous research indicated that TanshinoneⅡA exhibited its anti-cancer activity by several different pathways, including inhibiting the proliferation of cancer cell, increasing apoptosis, inhibiting the growth of cancer cell and also decreasing the oxidative damage that may cause the indirect anti-tumor effect. In my study, a total of 51 derivatives divided into 4 series were designed and synthesized to explore the angiogenic activity of TanshinoneⅡA.13 objective compounds of the first series were obtained by proceeding reduction-oxidation reaction on site 4 and site 5 of TanshinoneⅡA. An important intermediate compound (compound 2-1) was synthesized by formylation reaction which induced an aldehyde group onto the site 2 of TanshinoneⅡA. Then,25 objective compounds of the second series were obtained by a series of reaction based on the intermediate compound 2-1.7 derivatives of the third series were synthesized by bromine substitute reaction followed by alcoholysis and hydrolysis on the site 6 of compound 2-8 and compound 2-9.6 compounds of the forth series were synthesized from an intermediate compound 4-1 which was synthesized by oxidizing with selenium dioxide.40 out of 51 novel derivatives proceeded in vitro activity test, the result indicated that five of them exhibited more remarkable cell selectivity and more excellent inhibition activity against the proliferation of HUVEC (Human umbilical vein endothelial cell) compared with their mother compound TanshinoneⅡA (IC50 to HUVEC is 1.35μM), especially compound 2-9 (IC50 to HUVEC is 55 nM).Fumagillin, a natural product of fungal origin, was discovered as a potent inhibitor to restrain endothelial cell proliferation in vitro and block tumor angiogenesis in vivo. In order to further understand the biological mechanisms of fumagillin and its derivatives, a biotinylated fumagillin derivative of compound 6 was synthesized, which was linked by urethane bonds and amide bonds between fumagillol (2) and D-biotin. The structures of target and intermediate compounds were confirmed by MS,'H-NMR and 13C-NMR. The objective compound (6) showed excellent cell selectivity and inhibition activity (IC50 to HUVEC is 1.12 nM) against the proliferation of HUVEC. In vitro receptor-binding assay confirmed that the biotinylated derivative (compound 6) has a high binding affinity with Methionine aminopeptidase 2 (MetAP2) which was the main target of fumagillin as reported.