In vitro activity: Cytosporone B (Csn-B), an octaketide, is a naturally occurring agonist for the nuclear orphan receptor Nur77. Nuclear orphan receptor Nur77 has important roles in many biological processes. Csn-B binds specifically to the ligand-binding domain of Nur77 with high affinity (IC50=0.278 nM) and stimulates Nur77-dependent transactivational activity towards target genes including Nr4a1 (Nur77) itself, which contains multiple consensus response elements allowing positive autoregulation in a Csn-B-dependent manner. Csn-B also elevates blood glucose levels in fasting C57 mice, an effect that is accompanied by induction of multiple genes involved in gluconeogenesis.

Kinase Assay: Cytosporone B (Csn-B), an octaketide, is a naturally occurring agonist for the nuclear orphan receptor Nur77. Nuclear orphan receptor Nur77 has important roles in many biological processes. Csn-B binds specifically to the ligand-binding domain of Nur77 with high affinity (IC50=0.278 nM) and stimulates Nur77-dependent transactivational activity towards target genes including Nr4a1 (Nur77) itself, which contains multiple consensus response elements allowing positive autoregulation in a Csn-B-dependent manner.

Cell Assay: Human gastric cancer BGC-823 cells and human colon cancer SW620 cells are treated with cytosporone B for 72 h at 0-15 μg/mL. Cell viability is measured using the MTT assay