Cryptotanshinone (Tanshinone C)

2 years -80 in solvent

Orally

KATO III, DU145, PC3, LNCaP, MDA-MB-231, MDA-MB-468, MDA-MB-453, MCF-7, MCF-10A, HeLa and HCT-116

Dissolved in DMSO, final concentrations ca.50 uM

Dissolved in 0.1% solution of sodium lauryl sulfate

Cryptotanshinone, a natural compound isolated from the roots of Salvia miltiorrhiza Bunge (Danshen), significantly inhibits STAT3-dependent luciferase activity, the STAT3 Tyr705 phosphorylation and the dimerization of STAT3, compared to tanshinone IIA which exhibits no activity. Cryptotanshinone (7 uM) dramatically blocks STAT3 Tyr705 phosphorylation but not STAT3 Ser727 phosphorylation in DU145 cells, and significantly inhibits JAK2 phosphorylation with IC50 of ca.5 uM without affecting the phosphorylation of upstream kinases c-Src and EGFR, suggesting the inhibition of STAT3 Tyr705 phosphorylation might due to a direct mechanism probably by binding to the SH2 domain of STAT3. Cryptotanshinone significantly inhibits the proliferation of DU145 prostate cancer cells harboring constitutively active STAT3 with GI50 of 7 uM by blocking STAT3 activity, which leads to the down-regulation of cyclin D1, Bcl-xL, and survivin, subsequently the accumulation in the G0-G1 phase. Cryptotanshinone exhibits less growth inhibitory effect on PC3, LNCaP and MDA-MB-468 cells. [1]

24 or 48 hours

Cells are exposed to Cryptotanshinone for 24 or 48 hours. For the determination of cell proliferation, the cell proliferation reagent WST-1 is added and WST-1 formazan is quantitatively measured at 450 nm using an ELISA reader.

Cryptotanshinone (Tanshinone C) is a STAT3 inhibitor with IC50 of 4.6 μM in a cell-free assay, strongly inhibits phosphorylation of STAT3 Tyr705, with a small effect on STAT3 Ser727, but none against STAT1 nor STAT5. Cryptotanshinone induces ROS-dependent autophagy and mitochondria-mediated apoptosis.