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Bacterial communities associated with marine invertebrates such as sponges and ascidians have demonstrated potential as sources of bio-medically relevant small molecules. Metagenomic analysis has shown that many of these invertebrates harbor populations of Actinobacteria, many of which are cultivable. While some populations within invertebrates are transmitted vertically, others are obtained from the environment. We hypothesized that cultivable diversity from sponges living in brackish mangrove habitats have associations with Actinobacterial populations that differ from those found in clear tropical waters. In this study, we analyzed the cultivable Actinobacterial populations from sponges found in these two distinct habitats with the aim of understanding the secondary metabolite potential. Importantly, we wanted to broadly evaluate the potential differences among these groups to guide future Actinobacterial collection strategies for the purposes of drug discovery. [ABSTRACT FROM AUTHOR]

Two merotriterpenoid hydroquinone sulfates designated adociasulfate-13 (1) and adociasulfate-14 (2) were purified from Cladocroce acu!eata (Chalinidae) along with adociasulfate-8. All three compounds were found to inhibit microtubule-stimulated ATPase activ- ity of kinesin at 15 1tM by blocking both the binding of microtubules and the processive motion of kinesin along microtubules. These findings directly show that substitution of the 5'-sulfate in 1 for a glycolic acid moiety in 2 maintains kinesin inhibition. Nomarski imaging and bead diffusion assays in the presence of adociasulfates showed no signs of either free-floating or bead-bound adociasul- fate aggregates. Single-molecule biophysical experiments also suggest that inhibition of kinesin activity does not involve adociasulfate aggregation. Furthermore, both mitotic and nonmitotic kinesins are inhibited by adociasulfates to a significantly different extent. We also report evidence that microtubule binding of nonkinesin microtubule binding domains may be affected by adociasulfates. [ABSTRACT FROM AUTHOR]

Despite advancements in therapies developed for the treatment of cancer, patient prognosis and mortality rates have improved minimally, and metastasis remains the primary cause of cancer mortality worldwide. An underlying mechanism promoting metastasis in many types of cancer is epithelial-mesenchymal transition (EMT). Here the authors report a novel 3D model of EMT and metastatic breast cancer suitable for high-throughput screening (HTS) drug discovery. The primary assay incorporates the expression of the prognostic biomarker vimentin, as a luciferase reporter of EMT, in basil-like/triple-negative MDA-MB-231 breast carcinoma spheroids. Using this model, the authors developed a number of known antitumor agents as control modulators of EMT. U0126, PKC412, PF2341066, dasatinib, and axitinib downregulated vimentin expression by 70% to 90% as compared to untreated spheroids. Counterassays were developed to measure spheroid viability and the invasive potential of MDA-MB-231 spheroids after small-molecule treatment and used to confirm hits from primary screening. Finally, the authors conducted a pilot screen to validate this model for HTS using a purified library of marine secondary metabolites. From 230 compounds screened, they obtained a Z′ score of 0.64, indicative of an excellent assay, and confirmed 4 hits, including isonaamidine B, papuamine, mycalolide E, and jaspamide. This HTS model demonstrates the potential to identify small-molecule modulators of EMT that could be used to discover novel antimetastatic agents for the treatment of cancer. [ABSTRACT FROM PUBLISHER]

Wnt proteins are secreted post-translationally modified proteins that signal locally to regulate development and proliferation. The production of bioactive Wnts requires a number of dedicated factors in the secreting cell whose coordinated functions are not fully understood. A screen for small molecules identified inhibitors of vacuolar acidification as potent inhibitors of Wnt secretion. Inhibition of the V-ATPase or disruption of vacuolar pH gradients by diverse drugs potently inhibited Wnt/β-catenin signaling both in cultured human cells and in vivo, and impaired Wnt-regulated convergent extension movements in Xenopus embryos. WNT secretion requires its binding to the carrier protein wntless (WLS); we find that WLS is ER-resident in human cells and WNT3A binding to WLS requires PORCN-dependent lipid modification of WNT3A at serine 209. Inhibition of vacuolar acidification results in accumulation of the WNT3A-WLS complex both in cells and at the plasma membrane. Modeling predictions suggest that WLS has a lipid-binding β-barrel that is similar to the lipocalin-family fold. We propose that WLS binds Wnts in part through a lipid-binding domain, and that vacuolar acidification is required to release palmitoylated WNT3A from WLS in secretory vesicles, possibly to facilitate transfer of WNT3A to a soluble carrier protein. [ABSTRACT FROM AUTHOR]

Three new minor components, the pyridoacridine alkaloids 1-hydroxy-deoxyamphimedine (1), 3-hydroxy-deoxyamphimedine (2), debromopetrosamine (3), and three known compounds, amphimedine (4), neoamphimedine (5) and deoxyamphimedine (6), have been isolated from the sponge Xestospongia cf. carbonaria, collected in Palau. Structures were assigned on the basis of extensive 1D and 2D NMR studies as well as analysis by HRESIMS. Compounds 1-6 were evaluated in a zebrafish phenotype-based assay. Amphimedine (4) was the only compound that caused a phenotype in zebrafish embryos at 30 μM. No phenotype other than death was observed for compounds 1-3, 5, 6. [ABSTRACT FROM AUTHOR]

Bioassay-guided fractionation of two Philippine sponges of the genus Petrosia has resulted in the isolation of the novel natural product cribrostatin 7 ( 1 ) and the known compounds renierone ( 2 ) and O -demethylrenierone ( 3 ). The structures of these isoquinoline quinones were determined by interpretation of spectroscopic data. Compounds 1 , 2 and 3 were cytotoxic against the HCT 116 human colon carcinoma cell line with IC 50 values of 45, 24 and 34 µg/mL, respectively. [ABSTRACT FROM AUTHOR]

The National Cooperative Natural Products Drug Discovery Group (NCNPDDG) "Anticancer Agents from Unique Natural Products Sources, CA 67786" was first awarded in September 1995. The goal of the project is to discover and develop novel anticancer agents from a variety of natural products sources. The key accomplishments of this NCDDG which will be highlighted in this manuscript include: Development of tools to probe fungi for the production of novel natural products by DNA-based probes. Discovery that the majority of these fungi can produce natural products via nonribosomal peptide synthetases, polyketide synthases, or both - a much larger percentage than current culturing techniques reveal. Identification of the MDR-selective cytotoxic agent austocystin D, and use of a novel yeast deletion strain approach to help identify its molecular target(s). Identification of hemiasterlin and other naturally occurring analogs as potent antimitotic agents with excellent in vivo activity against human solid tumors in mouse models. Development of a total synthesis of hemiasterlin. The utilization of this methodology to provide the first SAR for the hemiasterlin family of antimitotic agents and to identify the synthetic analog HTI-286, which is being examined in clinical trials as an anticancer agent. To provided technology transfer, educational opportunities and compensation to countries of origin for collection and study of their natural product resources. This NCNPDDG program has provided funding to research programs at the University of the Philippines, The University of the South Pacific in the Fiji Islands, Colombo University in Sri Lanka, the Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Brazil, and the University of Papua New Guinea. [ABSTRACT FROM AUTHOR]

Deals with a study which screened marine invertebrate extracts in a set of isogenic colorectal cancer cells as part of a search for biologically active natural products from marine organisms. Experimental details; Results and discussion; Conclusion.

Patients diagnosed with basal-like breast cancer suffer from poor prognosis and limited treatment options. There is an urgent need to identify new targets that can benefit patients with basal-like and claudin-low (BL-CL) breast cancers. We screened fractions from our Marine Invertebrate Compound Library (MICL) to identify compounds that specifically target BL-CL breast cancers. We identified a previously unreported trisulfated sterol, i.e., topsentinol L trisulfate (TLT), which exhibited increased efficacy against BL-CL breast cancers relative to luminal/HER2+ breast cancer. Biochemical investigation of the effects of TLT on BL-CL cell lines revealed its ability to inhibit activation of AMP-activated protein kinase (AMPK) and checkpoint kinase 1 (CHK1) and to promote activation of p38. The importance of targeting AMPK and CHK1 in BL-CL cell lines was validated by treating a panel of breast cancer cell lines with known small molecule inhibitors of AMPK (dorsomorphin) and CHK1 (Ly2603618) and recording the increased effectiveness against BL-CL breast cancers as compared with luminal/HER2+ breast cancer. Finally, we generated a drug response gene-expression signature and projected it against a human tumor panel of 12 different cancer types to identify other cancer types sensitive to the compound. The TLT sensitivity gene-expression signature identified breast and bladder cancer as the most sensitive to TLT, while glioblastoma multiforme was the least sensitive. [ABSTRACT FROM AUTHOR]

Background: Rice (Oryza sativa) is one of the most important model crops in plant research. Despite its considerable advantages, (phenotypic) bioassays for rice are not as well developed as for Arabidopsis thaliana. Here, we present a phenotype-based screening method to study shoot-related parameters of rice seedlings via an automated computer analysis. Results: The phenotype-based screening method was validated by testing several compounds in pharmacological experiments that interfered with hormone homeostasis, confirming that the assay was consistent with regard to the anticipated plant growth regulation and revealing the robustness of the set-up in terms of reproducibility. Moreover, abiotic stress tests using NaCl and DCMU, an electron transport blocker during the light dependent reactions of photosynthesis, confirmed the validity of the new method for a wide range of applications. Next, this method was used to screen the impact of semi-purified fractions of marine invertebrates on the initial stages of rice seedling growth. Certain fractions clearly stimulated growth, whereas others inhibited it, especially in the root, illustrating the possible applications of this novel, robust, and fast phenotype-based screening method for rice. Conclusions: The validated phenotype-based and cost-efficient screening method allows a quick and proper analysis of shoot growth and requires only small volumes of compounds and media. As a result, this method could potentially be used for a whole range of applications, ranging from discovery of novel biostimulants, plant growth regulators, and plant growth-promoting bacteria to analysis of CRISPR knockouts, molecular plant breeding, genome-wide association, and phytotoxicity studies. The assay system described here can contribute to a better understanding of plant development in general. [ABSTRACT FROM AUTHOR]

Several known sesquiterpenoid quinones and quinols (1–9), and kauamide (10), a new polyketide-peptide containing an 11-membered heterocycle, were isolated from the extracts of the Hawaiian marine sponge Dactylospongiaelegans. The planar structure of 10 was determined from spectroscopic analyses, and its relative and absolute configurations were established from density functional theory (DFT) calculations of the GIAO NMR shielding tensors, and advanced Marfey's analysis of the N-MeLeu residue, respectively. Compounds 1 and 3 showed moderate inhibition of β-secretase 1 (BACE1), whereas 1–9 exhibited moderate to potent inhibition of growth of human glioma (U251) cells. Compounds 1–2 and 4–7 were also active against human pancreatic carcinoma (Panc-1) cells. [ABSTRACT FROM AUTHOR]

Several known sesquiterpenoid quinones and quinols (1–9), and kauamide (10), a new polyketide-peptide containing an 11-membered heterocycle, were isolated from the extracts of the Hawaiian marine sponge Dactylospongiaelegans. The planar structure of 10 was determined from spectroscopic analyses, and its relative and absolute configurations were established from density functional theory (DFT) calculations of the GIAO NMR shielding tensors, and advanced Marfey's analysis of the N-MeLeu residue, respectively. Compounds 1 and 3 showed moderate inhibition of β-secretase 1 (BACE1), whereas 1–9 exhibited moderate to potent inhibition of growth of human glioma (U251) cells. Compounds 1–2 and 4–7 were also active against human pancreatic carcinoma (Panc-1) cells. [ABSTRACT FROM AUTHOR]