Napabucasin (Synonyms: BBI 608)

Target: Signal transducer and activator of transcription 3 (Stat3)

IC50: 0.395 μM (Bulk cells), 0.142 μM (Cancer stem cells)

Napabucasin, also named (BBI608), is an orally available small molecule by the ability to inhibit gene transcription of STAT3 and cancer stemness properties and suppresses spherogenesis or kills stemnesshigh cancer cells isolated from several kinds of cancer types [1]. Stat3 is critically important for maintaining cancer stemness.

In vitro: Napabucasin (1 μmol/L) not only decreased cell viability, migration, colony formation, and survival with cell cycle arrest, and increased cell apoptosis and sensitivity to docetaxel, but also obviously blocked PrCSCs sphere formation and killed them in vitro [1]. Napabucasin (1, and 2 μmol/L) decreased the expressions of stemness markers such as Nanog, Klf4, survivin, C-myc, and β-catenin [1].

In vivo: Napabucasin (40 mg/kg, i.p. injection) inhibited tumor growth on prostate cancer (PCa) mouse xenograft models, the PC-3 cells or 22RV1 cells were inoculated into nude mice. In addition, Napabucasin suppressed the self-renewal of stemness-high prostate cancer (PCa) cells in vivo [1]. Moreover, Napabucasin (20 mg/kg, i.p. injection) effectively blocked cancer relapse and metastasis in xenografted human cancers including PaCa-2 human pancreatic cancer and HT29 human colon cancer [2].

References:
1.  Zhang Y, Jin Z, Zhou H, Ou X, Xu Y, Li H, et al. Suppression of prostate cancer progression by cancer cell stemness inhibitor napabucasin. Cancer Med. 2016;5(6):1251-8.
2.  Li Y, Rogoff HA, Keates S, Gao Y, Murikipudi S, Mikule K, et al. Suppression of cancer relapse and metastasis by inhibiting cancer stemness. Proc Natl Acad Sci U S A. 2015;112(6):1839-44.