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Modulators of Wnt signaling have therapeutic potential in a number of human diseases. A fractionated library from marine invertebrates was screened in a luciferase assay designed to identify modulators of Wnt signaling. A fraction from a Carteriospongia sp. sponge activated Wnt signaling and was subsequently shown to inhibit GSK-3beta, which inhibits Wnt signaling through phosphorylation of beta-catenin. Three novel natural products, carteriosulfonic acids A (1), B (2), and C (3), were identified as active constituents. The carteriosulfonic acids contain unprecedented 4,6,7,9-tetrahydroxylated decanoic acid subunits. Their structures were elucidated through analysis of NMR data and a detailed analysis of pseudo MS(3) spectra.

Three new sulfated sterol dimers, fibrosterol sulfates A-C (1-3), have been isolated from the sponge Lissodendoryx (Acanthodoryx) fibrosa, collected in the Philippines. The structures were assigned on the basis of extensive 1D and 2D NMR studies as well as analysis by HRESIMS. Compounds 1 and 2 inhibited PKCzeta with IC(50) values of 16.4 and 5.6 microM, respectively.

Three new sterol sulfates, spheciosterol sulfates A-C (1-3), and the known sterol sulfate topsentiasterol sulfate E (4) have been isolated from the sponge Spheciospongia sp., collected in the Philippines. Structures were assigned on the basis of extensive 1D and 2D NMR studies as well as analysis by HRESIMS. Compounds 1-4 inhibited PKCzeta with IC50 values of 1.59, 0.53, 0.11, and 1.21 microM, respectively. In a cell-based assay, 1-4 also inhibited NF-kappaB activation with EC50 values of 12-64 microM.

Microcionamides A (1) and B (2) have been isolated from the Philippine marine sponge Clathria (Thalysias) abietina. These new linear peptides are cyclized via a cystine moiety and have their C-terminus blocked by a 2-phenylethylenamine group. Their total structures, including absolute stereochemistry, were determined by a combination of spectral and chemical methods. Compound 1 was shown to slowly isomerize about the C-36/C-37 double bond when stored in DMSO. Microcionamides A (1) and B (2) exhibited significant cytotoxicity against the human breast tumor cells lines MCF-7 and SKBR-3 and displayed inhibitory activity against Mycobacterium tuberculosis H(37)Ra.

A detailed chemical analysis of a Philippine marine sponge Smenospongia sp. has been performed. This study yielded four new metabolites, 5-bromo-L-tryptophan (1), 5-bromoabrine (2), 5,6-dibromoabrine (3) and 5-bromoindole-3-acetic acid (4). The pyrroloiminoquinone alkaloid, makaluvamine O (5) as well as 5,6-dibromotryptamine (6), aureol (7) and furospinulosin 1 (8) were also isolated. Although 1 and 4 have been synthesized previously, this is the first report on the isolation of these compounds from a natural source. The furanosesterterpene furospinulosin 1 (8) was obtained for the first time from the genus Smenospongia. The structures of all compounds were established by spectroscopic methods (UV, IR, 1D and 2D NMR, MS, [alpha]D). The cytotoxic potential of 1-8 was evaluated in a panel of isogenic HCT-116 human colon tumor cell lines.

Investigation of a Philippine specimen of the red alga Ceratodictyon spongiosum and its sponge symbiont Haliclona cymaeformis led to the isolation of p-sulfooxyphenylpyruvic acid, whose structure was elucidated using spectroscopic methods, with the Z-enol geometry determined through analysis of (3)J(C,H) coupling constants. The metabolite was tested for tyrosine kinase inhibition using a (3)H-thymidine incorporation assay, but was found inactive.

Two new isomalabaricane triterpenes, stellettin H (1) and stellettin I (2), have been isolated from the marine sponge Rhabdastrella globostellata, collected from the Philippines. Stellettins A-D (3-6), (-)-stellettin E (7), and rhabdastrellic acid-A (8) were also isolated and characterized. Stellettin B (4) and (-)-stellettin E (7) showed selective cytotoxicity toward p21(WAF1/Cip1)-deficient human colon tumor (HCT-116) cells with IC(50) values of 0.043 and 0.039 microM, respectively.

Raf/MEK-1/MAPK cascade inhibitor activity-directed fractionation of the sponge Stylissa massa afforded eight known alkaloids: aldisine (1), 2-bromoaldisine (2), 10Z-debromohymenialdisine (3), 10E-hymenialdisine (4), 10Z-hymenialdisine (5), hymenin (6), oroidin (7), and 4,5-dibromopyrrole-2-carbonamide (8). Both 4 and 5 showed significant enzyme inhibitory activity (IC(50) 3 and 6 nM, respectively). Secondary assays identified these compounds as potent MEK-1 inhibitors. Compounds 4 and 5 also inhibited the growth of human tumor LoVo cells.