Biochem/physiol Actions

Ridaifen-B (RID-B) is a novel tamoxifen (TAM) analog that significantly augments apoptosis-inducing effect of TAM in estrogen receptor (ER)-negatives cells. Ridaifen-B induces mitochondria-involved apoptosis in Jurkat cells, as evidenced by chromatin-condensed cells as well as downstream activation of caspases (caspase-3, -8 and -9) in a dose- and time-dependent manner. At 4 hours of incubation, IC50 for RID-B is 4 muM (30 muM for TAM). And at prolonged treatment of 48 hours, IC50 for RID-B is 0.1 muM. In a related report on the global anti-tumor activity, RID-B strongly inhibits 39 human cancer cells (JFCR 39), both ER-+ or ER-- at concentrations of equal or less than 1muM (e.g., at 0.38muM for SF-539 [central nervous system], at 0.58muM for HT-29 [colon], at 0.20muM for DMS114 [lung], at 0.21muM for LOX-IMVI [melanoma], and at 0.23muM for MKN74 [stomach]. The binding protein of RID-B that exerts the apoptosis events is currently under investigation.

Features and Benefits

This compound is featured on the Nuclear Receptors (Steroids) page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.