Kazusamycin B

Kazusamycin B is a bacterial metabolite originally isolated from Streptomyces.¹ It has antifungal activity against S. pombe and R. javanicus (MICs = 0.05 and 2.13 µg/ml, respectively) but is inactive against Gram-positive and Gram-negative bacteria (MICs = >100 µg/ml). Kazusamycin B (5 ng/ml) halts the cell cycle at the G₁ phase and induces nuclear condensation in L1210 cells, as well as inhibits nuclear-to-cytosolic transport of the HIV-1 regulatory protein Rev in HeLa cells expressing Rev (IC₅₀ = 6.3 nM).^2,3 It is cytotoxic to L1210 and HCT-8 cells with IC₅₀ values of 1.8 and 1.6 ng/ml, respectively, and reduces tumor growth in a variety of murine tumor and mouse xenograft models.⁴

WARNING This product is not for human or veterinary use.

1. Funaishi, K., Kawamura, K., Sugiura, Y., et al. Kazusamycin B, a novel antitumor antibiotic. J. Antibiot. (Tokyo) 40(6), 778-785 (1987).

2. Takamiya, K., Yoshida, E., Takahashi, T., et al. The effect of kazusamycin B on the cell cycle and morphology of cultured L1210 cells. J. Antibiot. (Tokyo) 41(12), 1854-1861 (1988).

3. Wolff, B., Sanglier, J.-J., and Wang, Y. Leptomycin B is an inhibitor of nuclear export: inhibition of nucleo-cytoplasmic translocation of the human immunodeficiency virus type 1 (HIV-1) Rev protein and Rev-dependent mRNA. Chem. Biol. 4(2), 139-147 (1997).

4. Yoshida, E., Komiyama, K., Naito, K., et al. Antitumor effect of kazusamycin B on experimental tumors. J. Antibiot. (Tokyo) 40(11), 1596-1604 (1987).