A Pan-RAS Inhibitor with a Unique Mechanism of Action Blocks Tumor Growth and Induces Antitumor Immunity in Gastrointestinal Cancer.

RAS is a common driver of cancer that was considered undruggable for decades. Recent advances have enabled the development of RAS inhibitors, but the efficacy of these inhibitors remains limited by resistance. Here, we developed a pan-RAS inhibitor, ADT-007, that binds nucleotide-free RAS to block GTP activation of effector interactions and MAPK/AKT signaling, resulting in mitotic arrest and apoptosis.

A Novel Pan-RAS Inhibitor with a Unique Mechanism of Action Blocks Tumor Growth in Mouse Models of GI Cancer.

Unlabelled: Here, we describe a novel pan-RAS inhibitor, ADT-007, that potently inhibited the growth of RAS mutant cancer cells irrespective of the RAS mutation or isozyme. RAS cancer cells with GTP-activated RAS from upstream mutations were equally sensitive. Conversely, RAS cancer cells harboring downstream BRAF mutations and normal cells were essentially insensitive to ADT-007.

PDE5 and PDE10 inhibition activates cGMP/PKG signaling to block Wnt/β-catenin transcription, cancer cell growth, and tumor immunity.

Although numerous reports conclude that nonsteroidal anti-inflammatory drugs (NSAIDs) have anticancer activity, this common drug class is not recommended for long-term use because of potentially fatal toxicities from cyclooxygenase (COX) inhibition. Studies suggest the mechanism responsible for the anticancer activity of the NSAID sulindac is unrelated to COX inhibition but instead involves an off-target, phosphodiesterase (PDE). Thus, it might be feasible develop safer and more efficacious drugs for cancer indications by targeting PDE5 and PDE10, which are overexpressed in various tumors and essential for cancer cell growth.

Influenza A (H1N1) virus resistance to cyanovirin-N arises naturally during adaptation to mice and by passage in cell culture in the presence of the inhibitor.

Influenza A/New Caledonia/20/99 (H1N1) virus was studied for development of resistance to cyanovirin-N (CVN). CVN neutralizes virus infectivity by binding to specific high-mannose oligosaccharides on the viral haemagglutinin 1 (HA1) subunit. During virus adaptation to mice in the absence of CVN treatment the virus became resistant to CVN (CVN-MR virus), as did virus passaged in cell culture in the presence of CVN (CVN-R virus).

Candidaspongiolides, distinctive analogues of tedanolide from sponges of the genus Candidaspongia.

Fractionation of cytotoxic extracts of specimens of a newly described sponge genus, Candidaspongia, has yielded the candidaspongiolides (3), a complex mixture of acyl esters of a macrolide related to tedanolide. The general structure of the candidaspongiolides was determined by analyses of various 2D NMR and MS data sets. The acyl ester components were identified by GC-MS analysis of the derived fatty acid methyl esters.

Bioengineering lactic acid bacteria to secrete the HIV-1 virucide cyanovirin.

An urgent need exists to prevent the sexual transmission of HIV-1. With prevalence rates exceeding 35% in parts of sub-Saharan Africa, increasing attention has been placed on developing and testing microbicidal agents capable of preventing virus transmission at mucosal sites. HIV-1 microbicides must meet several requirements before their widespread use.

Antitumor activity and distribution of pyrroloiminoquinones in the sponge genus Zyzzya.

A detailed analysis of four different collections of the sponge genus Zyzzya yielded nine pyrroloiminoquinones of the makaluvamine, batzelline, and isobatzelline/damirone classes. Dereplication analyses of additional Zyzzya extracts did not disclose more potent or additional new compounds. Comparative testing of these compounds in the National Cancer Institute's 60 cell line human tumor screen revealed varying levels of potency and differential cytotoxicity, apparently related to the unsaturation levels in and substitution patterns on the core ring system.

Isolation and characterization of griffithsin, a novel HIV-inactivating protein, from the red alga Griffithsia sp.

Griffithsin (GRFT), a novel anti-HIV protein, was isolated from an aqueous extract of the red alga Griffithsia sp. The 121-amino acid sequence of GRFT has been determined, and biologically active GRFT was subsequently produced by expression of a corresponding DNA sequence in Escherichia coli. Both native and recombinant GRFT displayed potent antiviral activity against laboratory strains and primary isolates of T- and M- tropic HIV-1 with EC50 values ranging from 0.

Development of a fluorescent microplate assay for determining cyanovirin-N levels in plasma.

A sensitive immunosorbent competition assay was developed for quantitation of the anti-HIV protein cyanovirin-N (CV-N) in plasma using a 96-well plate format and a fluorescent endpoint. The assay is based on the binding of CV-N in plasma to plate-bound anti-CV-N antibodies, followed by removal of the plasma and addition of europium-labeled CV-N (Eu3+ -CV-N) to compete for the remaining antibody sites. Detection by addition of a dissociative fluorescence enhancement solution and time-resolved fluorescence measurements allowed correlation to the concentration of the native CV-N in plasma.

Neamphamide A, a new HIV-inhibitory depsipeptide from the Papua New Guinea marine sponge Neamphius huxleyi.

A new HIV-inhibitory cyclic depsipeptide, neamphamide A (2), was isolated from a Papua New Guinea collection of the marine sponge Neamphius huxleyi. Its structure was established through interpretation of spectroscopic data and by acid hydrolysis, derivatization of the free amino acids, and LC-MS analysis of the derivatives. Neamphamide A (2) contains 11 amino acid residues and an amide-linked 3-hydroxy-2,4,6-trimethylheptanoic acid moiety.

Cytotoxic alkaloids from the marine sponge Thorectandra sp.

Three beta-carboline alkaloids, Compound 1, 1-deoxysecofascaplysin A (2), and fascaplysin (3), were isolated from the aqueous and organic extracts of the marine sponge Thorectandra sp. The structures of 1 and 2 were determined on the basis of spectral data. Compound 1 inhibited the growth of MCF-7 (breast) with an IC50 of 5.

Gymnangiamide, a cytotoxic pentapeptide from the marine hydroid Gymnangium regae.

A cytotoxic aqueous extract from the marine hydroid Gymnangium regae provided a novel linear pentapeptide, designated gymnangiamide (1). The planar structure of 1 was elucidated by interpretation of spectral data as well as chemical degradation and derivatization studies. In addition to the amino acids isoleucine and phenylserine, this peptide contained N-desmethyldolaisoleuine, O-desmethyldolaproine, and alpha-guanidino serine, three residues that have not previously been reported in a natural product.

A frameshift mutation and alternate splicing in human brain generate a functional form of the pseudogene cytochrome P4502D7 that demethylates codeine to morphine.

A frameshift mutation 138delT generates an open reading frame in the pseudogene, cytochrome P4502D7 (CYP2D7), and an alternate spliced functional transcript of CYP2D7 containing partial inclusion of intron 6 was identified in human brain but not in liver or kidney from the same individual. mRNA and protein of the brain variant CYP2D7 were detected in 6 of 12 human autopsy brains. Genotyping revealed the presence of the frameshift mutation 138delT only in those human subjects who expressed the brain variant CYP2D7.

Cyclonellin, a new cyclic octapeptide from the marine sponge Axinella carteri.

Cyclonellin (1), a new cyclic octapeptide, was isolated from an aqueous extract of the marine sponge Axinella carteri. Its structure was elucidated by interpretation of NMR spectral data of the intact compound and N-terminal Edman sequencing of linear peptide fragments obtained by partial hydrolysis of 1. The absolute configurations of the constituent amino acids were determined by acid hydrolysis, derivitization with FDAA, and LC-MS analyses.

Cyanovirin-N inhibits AIDS virus infections in vaginal transmission models.

The cyanobacterial protein cyanovirin-N (CV-N) potently inactivates diverse strains of HIV-1 and other lentiviruses due to irreversible binding of CV-N to the viral envelope glycoprotein gp120. In this study, we show that recombinant CV-N effectively blocks HIV-1(Ba-L) infection of human ectocervical explants. Furthermore, we demonstrate the in vivo efficacy of CV-N gel in a vaginal challenge model by exposing CV-N-treated female macaques (Macaca fascicularis) to a pathogenic chimeric SIV/HIV-1 virus, SHIV89.

Identification of a new chondropsin class of antitumor compound that selectively inhibits V-ATPases.

We identify a new naturally occurring class of inhibitor of vacuolar H+-ATPases (V-ATPases) isolated from vacuolar membranes of Neurospora crassa and from chromaffin granule membranes of Bos taurus. To date, the new class includes six chondropsins and poecillastrin A, large polyketide-derived macrolide lactams with 33-37 membered rings. In the National Cancer Institute's 60-cell screen the chondropsin class showed a tumor cell growth inhibitory fingerprint essentially indistinguishable from that of the bafilomycin/concanamycin and the salicylihalamide/lobatamide classes of well-established V-ATPase inhibitors.

Cyanovirin-N gel as a topical microbicide prevents rectal transmission of SHIV89.6P in macaques.

Cyanovirin-N (CV-N), an 11-kDa cyanobacterial protein, potently inactivates diverse strains of HIV-1, HIV-2, and simian immunodeficiency virus (SIV) and also prevents virus-to-cell fusion, virus entry, and infection of cells in vitro. These properties make CV-N an attractive candidate for use as a topical microbicide to prevent the sexual transmission of HIV. We evaluated the efficacy of gel-formulated, recombinant CV-N gel asa topical microbicide in male macaques (Macaca fascicularis) that were rectally challenged with a chimeric SIV/HIV-1 virus known as SHIV89.

Potent anti-influenza activity of cyanovirin-N and interactions with viral hemagglutinin.

The novel antiviral protein cyanovirin-N (CV-N) was initially discovered based on its potent activity against the human immunodeficiency virus (HIV). Subsequent studies identified the HIV envelope glycoproteins gp120 and gp41 as molecular targets of CV-N. More recently, mechanistic studies have shown that certain high-mannose oligosaccharides (oligomannose-8 and oligomannose-9) found on the HIV envelope glycoproteins comprise the specific sites to which CV-N binds.

Cyanovirin-N binds to the viral surface glycoprotein, GP1,2 and inhibits infectivity of Ebola virus.

Ebola virus (Ebo) causes severe hemorrhagic fever and high mortality in humans. There are currently no effective therapies. Here, we have explored potential anti-Ebo activity of the human immunodeficiency virus (HIV)-inactivating protein cyanovirin-N (CV-N).

A potent novel anti-HIV protein from the cultured cyanobacterium Scytonema varium.

A new anti-HIV protein, scytovirin, was isolated from aqueous extracts of the cultured cyanobacterium Scytonema varium. The protein displayed potent anticytopathic activity against laboratory strains and primary isolates of HIV-1 with EC50 values ranging from 0.3 to 22 nM.

Multisite and multivalent binding between cyanovirin-N and branched oligomannosides: calorimetric and NMR characterization.

Binding of the protein cyanovirin-N to oligomannose-8 and oligomannose-9 of gp120 is crucially involved in its potent virucidal activity against the human immunodeficiency virus (HIV). The interaction between cyanovirin-N and these oligosaccharides has not been thoroughly characterized due to aggregation of the oligosaccharide-protein complexes. Here, cyanovirin-N's interaction with a nonamannoside, a structural analog of oligomannose-9, has been studied by nuclear magnetic resonance and isothermal titration calorimetry.

Functional homologs of cyanovirin-N amenable to mass production in prokaryotic and eukaryotic hosts.

Cyanovirin-N (CV-N) is under development as a topical (vaginal or rectal) microbicide to prevent sexual transmission of human immunodeficiency virus (HIV), and an economically feasible means for very large-scale production of the protein is an urgent priority. We observed that N-glycosylation of CV-N in yeast eliminated the anti-HIV activity, and that dimeric forms and aggregates of CV-N occurred under certain conditions, potentially complicating the efficient, large-scale manufacture of pure monomeric CV-N. We therefore expressed and tested CV-N homologs in which the glycosylation-susceptible Asn residue at position 30 was replaced with Ala, Gln, or Val, and/or the Pro at position 51 was replaced by Gly to eliminate potential conformational heterogeneity.

Thioltransferase (glutaredoxin) mediates recovery of motor neurons from excitotoxic mitochondrial injury.

Mitochondrial dysfunction involving electron transport components is implicated in the pathogenesis of several neurodegenerative disorders and is a critical event in excitotoxicity. Excitatory amino acid L-beta-N-oxalylamino-L-alanine (L-BOAA), causes progressive corticospinal neurodegeneration in humans. In mice, L-BOAA triggers glutathione loss and protein thiol oxidation that disrupts mitochondrial complex I selectively in motor cortex and lumbosacral cord, the regions affected in humans.

New dimeric macrolide glycosides from the marine sponge Myriastra clavosa.

Clavosolides A-D (1-4), dimeric macrolides incorporating cyclopropyl, tetrahydropyranyl, and glycosidic ring systems, were isolated from the cytotoxic extract of a Philippines collection of the marine sponge Myriastra clavosa. The structures of the clavosolides, which occurred as only trace metabolites, were elucidated through extensive NMR spectroscopic analyses. Clavosolides A (1) and B (2) were recently reported metabolites from M.

Isolation and structure of pedilstatin from a republic of maldives Pedilanthus sp.

A new cancer cell growth inhibitor designated pedilstatin (1) was isolated from a Republic of Maldives Pedilanthus sp. The structure was determined to be 13-O-acetyl-12-O-[2'Z,4'E-octadienoyl]-4alpha-deoxyphorbol on the basis of high-resolution mass spectral and 2D NMR assignments. Pedilstatin was found to significantly inhibit growth of the P388 lymphocytic leukemia cell line with an ED(50) of 0.