Isolating Prostate Cancer-Selective Naphthoquinone Derivatives from Streptomyces sp. CP59-55

By: Devin Simbol     

Department: Chemistry

Faculty Advisors: Dr. Taro Amagata, Dr. Frederick A. Valeriote, and Dr. Mark Swanson

The Amagata research group of San Francisco State University strives to identify cytotoxic secondary metabolites produced by marine-derived bacteria of class Actinomycetia that exhibit strong human solid tumor selectivity. During the testing of more than 500 strains using a cancer cell-based disk diffusion assay, Streptomyces sp. CP59-55 exhibited significant prostate cancer (LNCaP) selectivity and was selected for further study. A reversed-phase high-performance liquid chromatography (HPLC) profile of organic extract from a 1 L medium-scale culture indicated it contained more than 15 nonpolar compounds; UV spectrum analysis indicated these secondary metabolites contained naphthoquinone moiety. Reversed-phase HPLC is being used to purify these compounds prior to structural elucidation through 1H and 13C nuclear magnetic resonance (NMR) spectroscopic experiments. Napyradiomycin B4, a known cytotoxic compound, has been identified. New cytotoxic compounds with high LNCaP-selectivity are expected to be discovered as the remaining compounds in Streptomyces sp. CP59-55’s organic extract are characterized.