Cytotoxic Cyclolignans Obtained by the Enlargement of the Cyclolignan Skeleton of Podophyllic Aldehyde, a Selective Podophyllotoxin-Derived Cyclolignan

Podophyllotoxin, a cyclolignan natural product, has been the object of extensive chemomodulation to obtain better chemotherapeutic agents. Among the obtained podophyllotoxin derivatives, podophyllic aldehyde showed very interesting potency and selectivity against several tumoral cell lines, so it became our lead compound for further modifications, as described in this work, oriented toward the enlargement of the cyclolignan skeleton. Thus, modifications performed at the aldehyde function included nucleophilic addition reactions and the incorporation of the aldehyde carbon into several five-membered rings, such as thiazolidinones and benzo-fused azoles. The synthesized derivatives were evaluated against several types of cancer cells, and although some compounds were cytotoxic at the nanomolar range, most of them were less potent and less selective than the parent compound podophyllic aldehyde, with the most potent being those having the lactone ring of podophyllotoxin. In silico ADME evaluation predicted good druggability for most of them. The results indicate that the γ-lactone ring is important for potency, while the α,β-unsaturated aldehyde is necessary to induce selectivity in these cyclolignans.

Highly functionalized β-lactams and 2-ketopiperazines as TRPM8 antagonists with antiallodynic activity

The cool sensor transient receptor potential melastatin channel 8 (TRPM8) is highly expressed in trigeminal and dorsal root ganglia, playing a key role in cold hypersensitivity associated to different peripheral neuropathies. Moreover, these channels are aberrantly expressed in different cancers, and seem to participate in tumor progression, survival and invasion. Accordingly, the search for potent and selective TRPM8 modulators attracted great interest in recent years. We describe new heterocyclic TRPM8 antagonist chemotypes derived from N-cloroalkyl phenylalaninol-Phe conjugates. The cyclization of these conjugates afforded highly substituted β-lactams and/or 2-ketopiperazine (KP) derivatives, with regioselectivity depending on the N-chloroalkyl group and the configuration. These derivatives behave as TRPM8 antagonists in the Ca2+ microfluorometry assay, and confirmed electrophysiologically for the best enantiopure β-lactams 24a and 29a (IC50, 1.4 and 0.8 µM). Two putative binding sites by the pore zone, different from those found for typical agonists and antagonists, were identified by in silico studies for both β-lactams and KPs. β-Lactams 24a and 29a display antitumor activity in different human tumor cell lines (micromolar potencies, A549, HT29, PSN1), but correlation with TRPM8 expression could not be established. Additionally, compound 24a significantly reduced cold allodynia in a mice model of oxaliplatin-induced peripheral neuropathy.

Metabolite profiling of the novel anti-cancer agent, plitidepsin, in urine and faeces in cancer patients after administration of 14C-plitidepsin

PURPOSE

Plitidepsin absorption, distribution, metabolism and excretion characteristics were investigated in a mass balance study, in which six patients received a 3-h intravenous infusion containing 7 mg ¹⁴C-plitidepsin with a maximum radioactivity of 100 µCi.

METHODS

Blood samples were drawn and excreta were collected until less than 1% of the administered radioactivity was excreted per matrix for two consecutive days. Samples were pooled within-patients and between-patients and samples were screened for metabolites. Afterwards, metabolites were identified and quantified. Analysis was done using Liquid Chromatography linked to an Ion Trap Mass Spectrometer and offline Liquid Scintillation Counting (LC-Ion Trap MS-LSC).

RESULTS

On average 4.5 and 62.4% of the administered dose was excreted via urine over the first 24 h and in faeces over 240 h, respectively. Most metabolites were found in faeces.

CONCLUSION

Plitidepsin is extensively metabolised and it undergoes dealkylation (demethylation), oxidation, carbonyl reduction, and (internal) hydrolysis. The chemical formula of several metabolites was confirmed using high resolution mass data.

MI130004, a Novel Antibody-Drug Conjugate Combining Trastuzumab with a Molecule of Marine Origin, Shows Outstanding In Vivo Activity against HER2-Expressing Tumors

In the search for novel payloads to design new antibody-drug conjugates (ADC), marine compounds represent an interesting opportunity given their unique chemical features. PM050489 is a marine compound that binds β-tubulin at a new site and disrupts the microtubule network, hence leading to mitotic aberrations and cell death. PM050489 has been conjugated to trastuzumab via Cys residues through a noncleavable linker, and the resulting ADC, named MI130004, has been studied. Analysis of MI130004 delivered data consistent with the presence of two molecules of PM050489 per antibody molecule, likely bound to both sides of the intermolecular disulfide bond connecting the antibody light and heavy chains. The antitumor activity of MI130004 was analyzed in vitro and in vivo in different cell lines of diverse tumor origin (breast, ovary, and gastric cancer) expressing different levels of HER2. MI130004 showed very high in vitro potency and good selectivity for tumor cells that overexpressed HER2. At the cellular level, MI130004 impaired tubulin polymerization, causing disorganization and disintegration of the microtubule network, which ultimately led to mitotic failure, mirroring the effect of its payload. Treatment with MI130004 in mice carrying histologically diverse tumors expressing HER2 induced a long-lasting antitumor effect with statistically significant inhibition of tumor growth coupled with increases in median survival time compared with vehicle or trastuzumab. These results strongly suggest that MI130004 is endowed with remarkable anticancer activity and confirm the extraordinary potential of marine compounds for the design of new ADCs. Mol Cancer Ther; 17(4); 786-94. ©2018 AACR.

The effects of grape seed in the diet of the Penedes chicken, on growth and on the chemical composition and sensory profile of meat

1. Effect of a diet with 5% grape seed inclusion, substituting for maize compared to a standard diet, was studied in the Penedes chicken. 2. A total of 128 chickens were used, half from each sex. Individual weights and feed intake were controlled weekly from the first d to 5th week and fortnightly until the 15th week. On the 16th week, chemical analyses of meat from 16 thighs from each diet and sex were carried out, as well as a sensory analysis of meat from 24 thighs. Differences between diet and sex were analysed using live body weight, feed intake, feed conversion rate (FCR), chemical composition and sensory attributes of the meat. 3. At the end of the experiment, no significant differences were observed on live body weight, feed intake and FCR due to diet. 4. Meat showed no differences due to diet in the percentages of protein, lipid and ash. 5. Meat from the grape seed diet showed a higher percentage of unsaturated fatty acids due to linoleic acid. It also showed a more nutty smell, a more metallic flavour and more stringiness. There was, also, less of a pork crackling odour and flavour, a less sweet flavour and less of a broiler meat flavour.

The Aplidin analogs PM01215 and PM02781 inhibit angiogenesis in vitro and in vivo

BACKGROUND

Novel synthesized analogs of Aplidin, PM01215 and PM02781, were tested for antiangiogenic effects on primary human endothelial cells in vitro and for inhibition of angiogenesis and tumor growth in vivo.

METHODS

Antiangiogenic activity of both derivatives was evaluated by real-time cell proliferation, capillary tube formation and vascular endothelial growth factor (VEGF)-induced spheroid sprouting assays. Distribution of endothelial cells in the different phases of the cell cycle was analyzed by flow cytometry. Aplidin analogs were tested in vivo in chicken chorioallantoic membrane (CAM) assays.

RESULTS

Both derivatives inhibited angiogenic capacities of human endothelial cells (HUVECs) in vitro at low nanomolar concentrations. Antiangiogenic effects of both analogs were observed in the CAM. In addition, growth of human multiple myeloma xenografts in vivo in CAM was significantly reduced after application of both analogs. On the molecular level, both derivatives induced cell cycle arrest in G1 phase. This growth arrest of endothelial cells correlated with induction of the cell cycle inhibitor p16(INK4A) and increased senescence-associated beta galactosidase activity. In addition, Aplidin analogs induced oxidative stress and decreased production of the vascular maturation factors Vasohibin-1 and Dickkopf-3.

CONCLUSIONS

From these findings we conclude that both analogs are promising agents for the development of antiangiogenic drugs acting independent on classical inhibition of VEGF signaling.

Caracterización productiva de la gallina de Sobrarbe

Se aborda la caracterización productiva comparativa de las variedades negra y trigueña de la gallina de Sobrarbe, en lo referente a crecimiento (ganancia de peso, índices de conversión y rendimientos de canal), y puesta (número y calidad de los huevos). Los pollos machos alcanzaron los 2,1 kg de peso a las 19 semanas, con un índice de conversión de 4,5 y rendimiento de canal eviscerada cercano al 83 %. La puesta comenzo a las 20 semanas, con un resultado anual de 170 huevos. Solo se observaron diferencias significativas entre variedades, en las Unidades Haugh.

Synthesis, cytotoxicity and antiplasmodial activity of novel ent-kaurane derivatives

This paper reports on the syntheses and spectrometric characterisation of eleven novel ent-kaurane diterpenoids, including a complete set of (1)H, (13)C NMR and crystallographic data for two novel ent-kaurane diepoxides. Moreover, the antineoplastic cytotoxicity for kaurenoic acid and the majority of ent-kaurane derivatives were assessed in vitro against a panel of fourteen cancer cell lines, of which allylic alcohols were shown to be the most active compounds. The good in vitro antimalarial activity and the higher selectivity index values observed for some ent-kaurane epoxides against the chloroquine-resistant W2 clone of Plasmodium falciparum indicate that this class of natural products may provide new hits for the development of antimalarial drugs.

Stolonoxides E and F, cytotoxic metabolites from the marine ascidian Stolonica socialis

Two new members of the stolonoxide family, stolonoxides E (1) and F (2), were isolated from samples of the marine ascidian Stolonica socialis collected in Cádiz (Spain). Their structures were determined by a combination of techniques, including (+)-HRESIMS, 1D and 2D NMR spectroscopy, and comparison with published data for the structurally related stolonoxides A-D (3-6). Both compounds displayed cytotoxicity against a panel of three human tumor cell lines.

Cytotoxic staurosporines from the marine ascidian Cystodytes solitus

Two new indolocarbazole alkaloids, 7-oxo-3,8,9-trihydroxystaurosporine (1) and 7-oxo-8,9-dihydroxy-4'-N-demethylstaurosporine (2), were isolated from samples of the marine ascidian Cystodytes solitus. Their structures were determined by a combination of spectroscopic techniques, including (+)-HRMALDITOFMS and 1D and 2D NMR spectroscopy, and comparison with published data for related structures. Both compounds displayed strong cytotoxicity against three human tumor cell lines.

Double dearomatization of bis(diphenylphosphinamides) through anionic cyclization. A facile route of accessing multifunctional systems with antitumor properties

The sequential one-pot double dearomatization of bis(N-benzyl-P,P-diphenylphosphinamides) via anionic cyclization is described for the first time. Protonation and alkylation of the dearomatized dianions provide bis(tetrahydro-2,1-benzazaphospholes) in good yield and with very high regio- and stereocontrol. Acid-catalyzed methanolysis of the bisheterocycles affords bis(methyl gamma-aminophosphinates) stereospecifically. The doubly phosphorylated systems proved to be active against a series of cancer cell lines.

Smallest peptoids with antiproliferative activity on human neoplastic cells

Libraries of new, small peptoid monomers and dipeptoids were synthesized and assayed for antiproliferative activity against representative human neoplastic cell lines. The C-terminal N-alkyl amide peptoids are cytotoxic and are the smallest peptoids reported to have such activity. These compounds were conveniently synthesized on a BAL resin. Owing to their structure, the peptoids did not suffer from DKP formation, a problematic side reaction typically observed in peptide and peptoid synthesis.

Synthesis and Structure−Activity Relationship Study of Potent Cytotoxic Analogues of the Marine Alkaloid Lamellarin D

The marine alkaloid, Lamellarin D (Lam-D), has shown potent cytotoxicity in numerous cancer cell lines and was recently identified as a potent topoisomerase I inhibitor. A library of open lactone analogues of Lam-D was prepared from a methyl 5,6-dihydropyrrolo[2,1-a]isoquinoline-3-carboxylate scaffold (1) by introducing various aryl groups through sequential and regioselective bromination, followed by Pd(0)-catalyzed Suzuki cross-coupling chemistry. The compounds were obtained in a 24-44% overall yield, and tested in a panel of three human tumor cell lines, MDA-MB-231 (breast), A-549 (lung), and HT-29 (colon), to evaluate their cytotoxic potential. From these data, the SAR study concluded that more than 75% of the open-chain Lam-D analogues tested showed cytotoxicity in a low micromolar GI50 range.

Synthesis and cytotoxic evaluation of new derivatives of the marine alkaloid variolin B

The marine alkaloid variolin B 2 and eight synthetic derivatives with different substituents at positions C-5 and C-7 have been tested in a panel of sixteen human tumor cell lines to evaluate their cytotoxic potential.

Halogenated helianane derivatives from the sponge Spirastrella hartmani

Two new halogenated derivatives (1 and 2) of helianane (3) were isolated from the 2-propanol extract of the sponge Spirastrella hartmani. The structures of the new derivatives were determined on the basis of detailed spectroscopic analysis, including (+)-HREIMS and 1D and 2D NMR. Compound 1 showed in vitro cytotoxicity against the human tumor cell lines A549, HT29, and MDA-MB-231.

Topoisomerase I-mediated DNA cleavage as a guide to the development of antitumor agents derived from the marine alkaloid lamellarin D: triester derivatives incorporating amino acid residues

The marine alkaloid lamellarin D (LAM-D) has been recently characterized as a potent poison of human topoisomerase I endowed with remarkable cytotoxic activities against tumor cells. We report here the first structure-activity relationship study in the LAM-D series. Two groups of triester compounds incorporating various substituents on the three phenolic OH at positions 8, 14 and 20 of 6H-[1]benzopyrano[4',3':4,5]pyrrolo[2,1-a]isoquinolin-6-one pentacyclic planar chromophore typical of the parent alkaloid were tested as topoisomerase I inhibitors. The non-amino compounds in group A showed no activity against topoisomerase I and were essentially non cytotoxic. In sharp contrast, compounds in group B incorporating amino acid residues strongly promoted DNA cleavage by human topoisomerase I. LAM-D derivatives tri-substituted with leucine, valine, proline, phenylalanine or alanine residues, or a related amino side chain, stabilize topoisomerase I-DNA complexes. The DNA cleavage sites detected at T downward arrow G or C downward arrow G dinucleotides with these molecules were identical to that of LAM-D but slightly different from those seen with camptothecin which stimulates topoisomerase I-mediated cleavage at T downward arrow G only. In the DNA relaxation and cleavage assays, the corresponding Boc-protected compounds and the analogues of the non-planar LAM-501 derivative lacking the 5-6 double bond in the quinoline B-ring showed no effect on topoisomerase I and were considerably less cytotoxic than the corresponding cationic compounds in the LAM-D series. The presence of positive charges on the molecules enhances DNA interaction but melting temperature studies indicate that DNA binding is not correlated with topoisomerase I inhibition or cytotoxicity. Cell growth inhibition by the 41 lamellarin derivatives was evaluated with a panel of tumor cells lines. With prostate (DU-145 and LN-CaP), ovarian (IGROV and IGROV-ET resistant to ecteinascidin-743) and colon (LoVo and LoVo-Dox cells resistant to doxorubicin) cancer cells (but not with HT29 colon carcinoma cells), the most cytotoxic compounds correspond to the most potent topoisomerase I poisons. The observed correlation between cytotoxicity and topoisomerase I inhibition strongly suggests that topoisomerase I-mediated DNA cleavage assays can be used as a guide to the development of superior analogues in this series. LAM-D is the lead compound of a new promising family of antitumor agents targeting topoisomerase I and the amino acid derivatives appear to be excellent candidates for a preclinical development.

Identification of three single nucleotide polymorphisms in the chicken insulin-like growth factor 1 and 2 genes and their associations with growth and feeding traits

The chicken insulin-like growth factor (IGF)1 and IGF2 genes have been partially sequenced in six individuals of each of two chicken strains of the Black Penedesenca breed (PN and MN). These two strains are genetically diverse for growth traits. Sequence alignment revealed the existence of three single nucleotide polymorphisms (SNP) (IGF1-SNP1, IGF2-SNP2, and IGF2-SNP3). These three SNP and a fourth IGF1 polymorphism (IGF1-SNP4) were typed in 60 individuals from each strain by using PCR-RFLP or primer extension analysis. No significant associations among these four SNP, growth traits, and plasma IGF1 concentration were identified. In contrast, suggestive associations (P < or = 0.05) were found between IGF1-SNP1 and average daily gain at 107 d and feed efficiency at 44, 73, and 107 d. However, these associations were not simultaneously found in both strains suggesting that they might have been produced by linkage disequilibrium with another mutation located in the IGF1 locus or another linked gene. Since the PN and MN strains differ very markedly on their feed intake, the chicken leptin gene was included in the sequence analysis. Unfortunately, attempts to amplify several regions of this gene were unsuccessful. Even when primers complementary to highly conserved regions were used, the PCR consistently failed. Other authors have reported similar problems when trying to amplify avian leptin sequences.

Synthesis of ecteinascidin ET-743 and phthalascidin Pt-650 from cyanosafracin B

An efficient new process is described for the synthesis of ecteinascidin ET-743 (1) and phthalascidin (2), starting from readily available cyanosafracin B (3).

Genetic parameters for egg number, egg weight, and eggshell color in three Catalan poultry breeds

Heritabilities for egg number, egg weight, and eggshell color (percentage light absorbance) at 39 wk of age, and the genetic correlations between them were estimated by restricted maximum likelihood in three Catalan poultry breeds: Penedesenca Negra (PN), Prat Lleonada (PL), and Empordanesa Roja (ER). Additive genetic differences between these breeds were also estimated. Data were from the IRTA Poultry Genetic Conservation Program and consisted of records from 1,309 PN, 1,466 PL, and 1,440 ER hens, which were obtained from 80 contemporary batches per breed hatched between 1987 and 1992. Estimates of heritability for egg number, egg weight, and eggshell color were, 0.20, 0.59, and 0.49 for PN, 0.31, 0.48, and 0.53 for PL; and 0.33, 0.50, and 0.27 for ER. Estimated genetic correlations between egg number and egg weight, egg number and shell color, and egg weight and shell color were, for PN, -0.22, -0.03, and 0.00; for PL, -0.21, -0.06, and 0.09; and -0.19, -0.29, and 0.30 for ER. Heritability for eggshell color and genetic correlation between eggshell color and other traits showed a different genetic pattern in ER breed. Significant additive genetic differences (P < 0.05) were found between ER and PN base populations for egg number (3.89), egg weight (0.91), and eggshell color (-3.50); and between ER and PL for egg number (6.69) and eggshell color (35.39). The PN and PL breeds differed significantly (P < 0.05) for eggshell color (38.22), which was darker in PN. These results could be taken as the expected genetic differences for these breeds.

Synthesis of Retinals Fluorinated at Odd-Numbered Side-Chain Positions and of the Corresponding Fluorobacteriorhodopsins

Conventional Horner-Wadsworth-Emmons and Wittig condensations were used to fluorinate the odd-numbered positions of the retinal side chain past C(7). The stereochemically labile cis-fluororetinals were easily converted into the most stable trans-fluororetinals, which were incubated with bacterio-opsin. Contrary to expectations, the fluorinated retinals provided artificial pigments with near normal absorption properties, showing that any electrostatic interactions between the fluorine atoms and protein groups were insufficient to prevent normal binding. The new artificial pigments had smaller opsin shifts than did native bacteriorhodopsin, which is interpreted as due either to greater electrostatic interaction between the protonated imine and its counterion, or to local interactions between the fluorine substituents and nearby polar protein groups.

Fourier transform infrared spectroscopy indicates a major conformational rearrangement in the activation of rhodopsin

The study of the structural differences between rhodopsin and its active form (metarhodopsin II) has been carried out by means of deconvolution analysis of infrared spectra. Deconvolution techniques allow the direct identification of the spectral changes that have occurred, which results in a significantly different view of the conformational changes occurring after activation of the receptor as compared with previous difference spectroscopy analysis. Thus, a number of changes in the bands assigned to solvent-exposed domains of the receptor are detected, indicating significant decreases in extended (beta) sequences and in reverse turns, and increases in irregular/aperiodic sequences and in helices with a non-alpha geometry, whereas there is no decrease in alpha-helices. In addition to secondary structure conversions, qualitative alterations within a given secondary structure type are detected. These are seen to occur in both reverse turns and helices. The nature of this spectral change is of great importance, since a clear alteration in the helices bundle core is detected. All these changes indicate that the rhodopsin --> metarhodopsin II transition involves not a minor but a major conformational rearrangement, reconciling the infrared data with the energetics of the activation process.