丹参酮ⅡA对小鼠肠癌皮下移植瘤血管新生的抑制作用

Tanshinones: sources, pharmacokinetics and anti-cancer activities

Tanshinones are a class of abietane diterpene compound isolated from Salvia miltiorrhiza (Danshen or Tanshen in Chinese), a well-known herb in Traditional Chinese Medicine (TCM). Since they were first identified in the 1930s, more than 40 lipophilic tanshinones and structurally related compounds have been isolated from Danshen. In recent decades, numerous studies have been conducted to investigate the isolation, identification, synthesis and pharmacology of tanshinones. In addition to the well-studied cardiovascular activities, tanshinones have been investigated more recently for their anti-cancer activities in vitro and in vivo. In this review, we update the herbal and alternative sources of tanshinones, and the pharmacokinetics of selected tanshinones. We discuss anti-cancer properties and identify critical issues for future research. Whereas previous studies have suggested anti-cancer potential of tanshinones affecting multiple cellular processes and molecular targets in cell culture models, data from in vivo potency assessment experiments in preclinical models vary greatly due to lack of uniformity of solvent vehicles and routes of administration. Chemical modifications and novel formulations had been made to address the poor oral bioavailability of tanshinones. So far, human clinical trials have been far from ideal in their design and execution for the purpose of supporting an anti-cancer indication of tanshinones.

Tan IIA inhibits COX-2-regulated VEGF expression in human colon cancer HCT-116 cells

AIM: To investigate the effect of tanshinone IIA (Tan IIA), an active component of salvia miltiorrhiza, on cell proliferation and cyclooxygenase-2 (COX-2)-regulated vascular endothelial growth factor (VEGF) expression in human colon cancer HCT-116 cells.

METHODS: MTT assay was used to evaluate the effect of Tan IIA on the proliferation of HCT-116 cells. HCT-116 cells were co-transfected transiently with the recombinant plasmid pGL3-Basic-COX-2-promoter and control vector pRL-TK and randomly divided into blank group, control group, and Tan IIA group. Dual luciferase reporter assay was used to observe the activity of COX-2 promoter 48 h after treatment with Tan IIA. HCT-116 cells were transfected with the pIRESI-COX-2 plasmid and divided into three groups as above. The expression of COX-2 mRNA in transfected cells was detected by real-time PCR, and the level of VEGF in culture medium was assayed by ELISA.

RESULTS: Tan IIA had obvious inhibition on the proliferation of HCT-116 cells. The half maximal inhibitory concentrations (IC₅₀) at 24, 48, and 72 h were 40.3 μmol/L ± 5.22 μmol/L, 12.9 μmol/L ± 3.24 μmol/L, and 8.5 μmol/L ± 1.47 μmol/L, respectively, and the maximal no-effect dose at 24 h was 10 μmol/L. At 48 h after transfection with plasmids carrying the COX-2-promoter and COX-2 cDNA, the activity of COX-2 promoter and expression of COX-2 mRNA were obviously up-regulated (both P < 0.01), and the concentration of VEGF was three times higher than that in control cells (P < 0.05). Treatment with 10 μmol/L Tan IIA significantly down-regulated the expression of COX-2 and VEGF in transfected cells (P < 0.05).

CONCLUSION: Tan IIA down-regulates VEGF expression and inhibits cell proliferation possibly by regulating COX-2 promoter activity and mRNA expression in HCT-116 cells.