Inhibitory effects of Kampo medicines, Keishibukuryogan and Shakuyakukanzoto, on the substrate uptake activities of solute carrier organic anion transporters.

The aim of this study was to assess the effects of Keishibukuryogan (K-06) and Shakuyakukanzoto (TJ-68), commercial herbal medicines, on the substrate uptake activities of renal organic anion transporters. We performed transporter uptake and cell viability assays in Xenopus oocytes and HEK293 human kidney embryonic cells treated with K-06 or TJ-68. K-06 and TJ-68 markedly inhibited the substrate uptake activities of URAT1, OAT1, and OAT3, while they did not exhibit non-cytotoxic effects. Our findings demonstrated that K-06 and TJ-68 inhibited the substrate uptake activities of renal transporters, suggesting their mechanism of action as nephroprotective agents.

Decursin suppresses human androgen-independent PC3 prostate cancer cell proliferation by promoting the degradation of beta-catenin.

Alterations in the Wnt/beta-catenin pathway are associated with the development and progression of human prostate cancer. Decursin, a pyranocoumarin isolated from the Korean Angelica gigas root, inhibits the growth of androgen-independent human prostate cancer cells, but little is known about its mechanism of action. Using a cell-based screen, we found that decursin attenuates the Wnt/beta-catenin pathway. Decursin antagonized beta-catenin response transcription (CRT), which was induced with Wnt3a-conditioned medium and LiCl, by promoting the degradation of beta-catenin. Furthermore, decursin suppressed the expression of cyclin D1 and c-myc, which are downstream target genes of beta-catenin and thus inhibited the growth of PC3 prostate cancer cells. In contrast, decursinol, in which the (CH3)2-C=CH-COO- side chain of decursin is replaced with -OH, had no effect on CRT, the level of intracellular beta-catenin, or PC3 cell proliferation. Our findings suggest that decursin exerts its anticancer activity in prostate cancer cells via inhibition of the Wnt/beta-catenin pathway.