CITCO, an imidazothiazole derivative, is a selective Constitutive androstane receptor (CAR) agonist. CITCO inhibits growth and expansion of brain tumour stem cells (BTSCs) and has an EC50 of 49 nM over pregnane X receptor (PXR), and no activity on other nuclear receptors[1].
CITCO (1-50 μM; 48 hours) results in a dose-dependent inhibition of viable cell count and proliferation in both T98G and U87MG glioma and BTSCs[1]. CITCO (2.5, 5 μM; 48 hours) induces cell cycle arrest differentially in different BTSCs in culture, but not in normal astrocytes[1]. CITCO (2.5-10 μM; 48 hours) induces apoptosis in BTSCs in culture in dose dependently, but not in normal astrocytes[1]. CITCO (0-25 μM; 48 hours) causes the T98G and U87MG glioma and BTSCs expressing very low levels of CAR protein that increased significantly[1].
CITCO (intraperitoneal; on days 22, 24, 26, 30 and 36) with 25 μg results a significant decrease in tumour growth, which further decreases to an undetectable level after treatment with 100 μg CITCO [1].
References:
[1]. Chakraborty S, et al. Constitutive androstane receptor agonist CITCO inhibits growth and expansion of brain tumour stem cells. Br J Cancer. 2011 Feb 1;104(3):448-59.