GKB202

GKB202 is a **natural small-molecule compound** derived from the mycelium of *Antrodia cinnamomea*, a medicinal fungus. It has demonstrated **anti-cancer properties**, particularly through the cytotoxic sensitization of tumor cells when combined with 5-fluorouracil (5-FU) and by inhibiting the survival and function of **circulating tumor cells (CTCs)**. Mechanistically, GKB202 suppresses **endothelin-1 (ET-1)** production and downstream **ERK** signaling pathways in both tumor and endothelial cells and acts as an **endothelin receptor type B (ETBR) antagonist**, disrupting signaling linked to tumor metastasis and angiogenesis. Preclinical studies indicate rapid hepatic clearance and good tolerability in animals up to 20 mg/kg orally, with no significant toxicity observed. The compound is positioned as a novel candidate for anti-cancer therapy, especially in combination with established chemotherapeutic agents[1][3][5][7][8][9].