Gunasekera, Sarath P., Imperial, Lorelie, Garst, Christiana, Ratnayake, Ranjala, Dang, Long H., Paul, Valerie J., and Luesch, Hendrik. 2016. "Caldoramide, a Modified Pentapeptide from the Marine Cyanobacterium Caldora penicillata." Journal of natural products 79 (7):1867-1871. https://doi.org/10.1021/acs.jnatprod.6b00203
The isolation, structure determination, and biological activities of a new linear pentapeptide, caldoramide (5), from the marine cyanobacterium Caldora penicillata from Florida are described. Caldoramide (5) has structural similarities to belamide A (4), dolastatin 10 (1), and dolastatin 15 (2). We profiled caldoramide against parental HCT116 colorectal cancer cells and isogenic cells lacking oncogenic KRAS or hypoxia-inducible factors 1? (HIF-1?) and 2? (HIF-2?). Caldoramide (5) showed differential cytotoxicity for cells containing both oncogenic KRAS and HIF over the corresponding knockout cells. LCMS dereplication indicated the presence of caldoramide (5) in a subset of C. penicillata samples.