Cytotoxic Metabolites Research Articles

Abstract 1359: Evaluation of the therapeutic potential of AIMZ-938 as a new cytochrome p450 1A1-selective prodrug for the treatment of breast cancers

Abstract Breast cancers (BC) are the most common cancers among women in North America. Several BC show high relapse rates or chemoresistance to current chemotherapies. Hence it is essential to develop new therapies to cure BC that would otherwise be lethal due to the absence of alternative treatments. To get around this issue, we developed AIMZ-938, a phenyl 4-(2-oxo-3-alkylimidazolidin-1-yl)benzenesulfonate, member of a novel class of cytochrome P450 1A1 (CYP1A1)-dependent prodrugs releasing selective and highly cytotoxic antimitotic metabolites in BC tumors expressing CYP1A1. AIMZ-938 does not exhibit toxicity in normal cells not expressing CYP1A1, a property that protects normal tissues from chemotherapy-derived side effects. The aims of our work are to evaluate in mouse models 1) the maximal tolerated dose of AIMZ-938, 2) its half-life (t1/2) and 3) its antitumor activity in a xenograft model of BC. The maximal tolerated dose (MTD) of AIMZ-938 and its t1/2 were assessed on CD-1 female mice. The MTD of AIMZ-938 was evaluated at a concentration of 0.5 mg/mL with a sequential increase of 1/2 logarithmic value until the MTD was reached. AIMZ-938 was administered to mice as a single IV dose at the MTD concentration and t1/2 was evaluated using collected blood samples obtained through a terminal cardiac puncture at 0, 30, 60, 120, 240, 480, 960 and 1440 minutes. The AIMZ-938 concentrations were quantified by UHPLC-UV. Then, the antitumor activity of AIMZ-938 was assessed using a MCF7 xenograft CD-1 female nude mouse model. Briefly, the human breast cancer model was produced by a subcutaneous implantation of a 17 beta-estradiol pellet in each animal flank followed by the inoculation of MCF7 cells one week later in the opposite flank. When the tumors reached a volume of 50-100 mm3, AIMZ-938 was administered IV biweekly to the animals for three weeks. Paclitaxel was used as positive control and was administered weekly for three weeks while a saline solution and the vehicle were used as negative controls. The tumor growth was measured biweekly using a metric Vernier caliper and the evaluation of the side effects was conducted daily. Our results showed that AIMZ-938 is sparingly soluble in our vehicle (0.8 mg/mL) and this concentration was fixed for further administrations. Half-life of IV administered AIMZ-938 was 11.5 ± 1.1 h, strongly suggesting that this compound is suitable for further pharmacodynamic studies. Moreover, AIMZ-938 did not exhibit significant side effects in animals at its highest concentration (0.8 mg/mL) when administered IV biweekly for 3 weeks. Finally, AIMZ-938 exhibited potent antitumor activity, similar to paclitaxel, a standard first-line treatment for breast cancer. AIMZ-938 is highly potent and a promising new targeted antimitotic prodrug for the treatment of breast cancers expressing CYP1A1. Citation Format: Atziri Corin Chavez Alvarez, Chahrazed Bouzriba, Mathieu Gagné-Boulet, Sylvie Pilote, René C.-Gaudreault, Chantale Simard, Sébastien Fortin. Evaluation of the therapeutic potential of AIMZ-938 as a new cytochrome p450 1A1-selective prodrug for the treatment of breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1359.

Streptomyces griseus KJ623766: A Natural Producer of Two Anthracycline Cytotoxic Metabolites β- and γ-Rhodomycinone.

Background: This study aimed to produce, purify, structurally elucidate, and explore the biological activities of metabolites produced by Streptomyces (S.) griseus isolate KJ623766, a recovered soil bacterium previously screened in our lab that showed promising cytotoxic activities against various cancer cell lines. Methods: Production of cytotoxic metabolites from S. griseus isolate KJ623766 was carried out in a 14L laboratory fermenter under specified optimum conditions. Using a 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium-bromide assay, the cytotoxic activity of the ethyl acetate extract against Caco2 and Hela cancer cell lines was determined. Bioassay-guided fractionation of the ethyl acetate extract using different chromatographic techniques was used for cytotoxic metabolite purification. Chemical structures of the purified metabolites were identified using mass, 1D, and 2D NMR spectroscopic analysis. Results: Bioassay-guided fractionation of the ethyl acetate extract led to the purification of two cytotoxic metabolites, R1 and R2, of reproducible amounts of 5 and 1.5 mg/L, respectively. The structures of R1 and R2 metabolites were identified as β- and γ-rhodomycinone with CD50 of 6.3, 9.45, 64.8 and 9.11, 9.35, 67.3 µg/mL against Caco2, Hela and Vero cell lines, respectively. Values were comparable to those of the positive control doxorubicin. Conclusions: This is the first report about the production of β- and γ-rhodomycinone, two important scaffolds for synthesis of anticancer drugs, from S. griseus.

Insights into the Cultured Bacterial Fraction of Corals.

ABSTRACTBacteria associated with coral hosts are diverse and abundant, with recent studies suggesting involvement of these symbionts in host resilience to anthropogenic stress. Despite their putative importance, the work dedicated to culturing coral-associated bacteria has received little attention. Combining published and unpublished data, here we report a comprehensive overview of the diversity and function of culturable bacteria isolated from corals originating from tropical, temperate, and cold-water habitats. A total of 3,055 isolates from 52 studies were considered by our metasurvey. Of these, 1,045 had full-length 16S rRNA gene sequences, spanning 138 formally described and 12 putatively novel bacterial genera across the Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria phyla. We performed comparative genomic analysis using the available genomes of 74 strains and identified potential signatures of beneficial bacterium-coral symbioses among the strains. Our analysis revealed >400 biosynthetic gene clusters that underlie the biosynthesis of antioxidant, antimicrobial, cytotoxic, and other secondary metabolites. Moreover, we uncovered genomic features—not previously described for coral-bacterium symbioses—potentially involved in host colonization and host-symbiont recognition, antiviral defense mechanisms, and/or integrated metabolic interactions, which we suggest as novel targets for the screening of coral probiotics. Our results highlight the importance of bacterial cultures to elucidate coral holobiont functioning and guide the selection of probiotic candidates to promote coral resilience and improve holistic and customized reef restoration and rehabilitation efforts.IMPORTANCE Our paper is the first study to synthesize currently available but decentralized data of cultured microbes associated with corals. We were able to collate 3,055 isolates across a number of published studies and unpublished collections from various laboratories and researchers around the world. This equated to 1,045 individual isolates which had full-length 16S rRNA gene sequences, after filtering of the original 3,055. We also explored which of these had genomes available. Originally, only 36 were available, and as part of this study, we added a further 38—equating to 74 in total. From this, we investigated potential genetic signatures that may facilitate a host-associated lifestyle. Further, such a resource is an important step in the selection of probiotic candidates, which are being investigated for promoting coral resilience and potentially applied as a novel strategy in reef restoration and rehabilitation efforts. In the spirit of open access, we have ensured this collection is available to the wider research community through the web site http://isolates.reefgenomics.org/ with the hope many scientists across the globe will ask for access to these cultures for future studies.

Variants in the ethylmalonyl-CoA decarboxylase (ECHDC1) gene: a novel player in ethylmalonic aciduria?

Ethylmalonic acid (EMA) is a major and potentially cytotoxic metabolite associated with short‐chain acyl‐CoA dehydrogenase (SCAD) deficiency, a condition whose status as a disease is uncertain. Unexplained high EMA is observed in some individuals with complex neurological symptoms, who carry the SCAD gene (ACADS) variants, c.625G>A and c.511C>T. The variants have a high allele frequency in the general population, but are significantly overrepresented in individuals with elevated EMA. This has led to the idea that these variants need to be associated with variants in other genes to cause hyperexcretion of ethylmalonic acid and possibly a diseased state. Ethylmalonyl‐CoA decarboxylase (ECHDC1) has been described and characterized as an EMA metabolite repair enzyme, however, its clinical relevance has never been investigated. In this study, we sequenced the ECHDC1 gene (ECHDC1) in 82 individuals, who were reported with unexplained high EMA levels due to the presence of the common ACADS variants only. Three individuals with ACADS c.625G>A variants were found to be heterozygous for ECHDC1 loss‐of‐function variants. Knockdown experiments of ECHDC1, in healthy human cells with different ACADS c.625G>A genotypes, showed that ECHDC1 haploinsufficiency and homozygosity for the ACADS c.625G>A variant had a synergistic effect on cellular EMA excretion. This study reports the first cases of ECHDC1 gene defects in humans and suggests that ECHDC1 may be involved in elevated EMA excretion in only a small group of individuals with the common ACADS variants. However, a direct link between ECHDC1/ACADS deficiency, EMA and disease could not be proven.

Engineering the Escherichia coli Nitroreductase NfsA to Create a Flexible Enzyme-Prodrug Activation System.

Bacterial nitroreductase enzymes that can efficiently convert nitroaromatic prodrugs to a cytotoxic form have numerous applications in targeted cellular ablation. For example, the generation of cytotoxic metabolites that have low bystander potential (i.e., are largely confined to the activating cell) has been exploited for precise ablation of specific cell types in animal and cell-culture models; while enzyme-prodrug combinations that generate high levels of bystander cell killing are useful for anti-cancer strategies such as gene-directed enzyme-prodrug therapy (GDEPT). Despite receiving substantial attention for such applications, the canonical nitroreductase NfsB from Escherichia coli has flaws that limit its utility, in particular a low efficiency of conversion of most prodrugs. Here, we sought to engineer a superior broad-range nitroreductase, E. coli NfsA, for improved activity with three therapeutically-relevant prodrugs: the duocarmycin analogue nitro-CBI-DEI, the dinitrobenzamide aziridine CB1954 and the 5-nitroimidazole metronidazole. The former two prodrugs have applications in GDEPT, while the latter has been employed for targeted ablation experiments and as a precise ‘off-switch’ in GDEPT models to eliminate nitroreductase-expressing cells. Our lead engineered NfsA (variant 11_78, with the residue substitutions S41Y, L103M, K222E and R225A) generated reduced metabolites of CB1954 and nitro-CBI-DEI that exhibited high bystander efficiencies in both bacterial and 2D HEK-293 cell culture models, while no cell-to-cell transfer was evident for the reduced metronidazole metabolite. We showed that the high bystander efficiency for CB1954 could be attributed to near-exclusive generation of the 2-hydroxylamine reduction product, which has been shown in 3D cell culture to cause significantly greater bystander killing than the 4-hydroxylamine species that is also produced by NfsB. We similarly observed a high bystander effect for nitro-CBI-DEI in HCT-116 tumor spheroids in which only a small proportion of cells were expressing variant 11_78. Collectively, our data identify variant 11_78 as a broadly improved prodrug-activating nitroreductase that offers advantages for both targeted cellular ablation and suicide gene therapy applications.

Exposure to the Methylselenol Precursor Dimethyldiselenide Induces a Reductive Endoplasmic Reticulum Stress in Saccharomyces cerevisiae.

Methylselenol (MeSeH) is a major cytotoxic metabolite of selenium, causing apoptosis in cancer cells through mechanisms that remain to be fully established. Previously, we demonstrated that, in Saccharomyces cerevisiae, MeSeH toxicity was mediated by its metabolization into selenomethionine by O-acetylhomoserine (OAH)-sulfhydrylase, an enzyme that is absent in higher eukaryotes. In this report, we used a mutant met17 yeast strain, devoid of OAH- sulfhydrylase activity, to identify alternative targets of MeSeH. Exposure to dimethyldiselenide (DMDSe), a direct precursor of MeSeH, caused an endoplasmic reticulum (ER) stress, as evidenced by increased expression of the ER chaperone Kar2p. Mutant strains (∆ire1 and ∆hac1) unable to activate the unfolded protein response were hypersensitive to MeSeH precursors but not to selenomethionine. In contrast, deletion of YAP1 or SKN7, required to activate the oxidative stress response, did not affect cell growth in the presence of DMDSe. ER maturation of newly synthesized carboxypeptidase Y was impaired, indicating that MeSeH/DMDSe caused protein misfolding in the ER. Exposure to DMDSe resulted in induction of the expression of the ER oxidoreductase Ero1p with concomitant reduction of its regulatory disulfide bonds. These results suggest that MeSeH disturbs protein folding in the ER by generating a reductive stress in this compartment.

Combination of Mesenchymal Stem Cell-Delivered Oncolytic Virus with Prodrug Activation Increases Efficacy and Safety of Colorectal Cancer Therapy.

Although oncolytic viruses are currently being evaluated for cancer treatment in clinical trials, systemic administration is hindered by many factors that prevent them from reaching the tumor cells. When administered systemically, mesenchymal stem cells (MSCs) target tumors, and therefore constitute good cell carriers for oncolytic viruses. MSCs were primed with trichostatin A under hypoxia, which upregulated the expression of CXCR4, a chemokine receptor involved in tumor tropism, and coxsackievirus and adenovirus receptor that plays an important role in adenoviral infection. After priming, MSCs were loaded with conditionally replicative adenovirus that exhibits limited proliferation in cells with a functional p53 pathway and encodes Escherichia coli nitroreductase (NTR) enzymes (CRAdNTR) for targeting tumor cells. Primed MSCs increased tumor tropism and susceptibility to adenoviral infection, and successfully protected CRAdNTR from neutralization by anti-adenovirus antibodies both in vitro and in vivo, and specifically targeted p53-deficient colorectal tumors when infused intravenously. Analyses of deproteinized tissues by UPLC-MS/QTOF revealed that these MSCs converted the co-administered prodrug CB1954 into cytotoxic metabolites, such as 4-hydroxylamine and 2-amine, inducing oncolysis and tumor growth inhibition without being toxic for the host vital organs. This study shows that the combination of oncolytic viruses delivered by MSCs with the activation of prodrugs is a new cancer treatment strategy that provides a new approach for the development of oncolytic viral therapy for various cancers.

Metabolomic fingerprinting of Brazilian marine sponges: a case study of Plakinidae species from Fernando de Noronha Archipelago.

Marine sponges from the Plakinidae family are well known for hosting cytotoxic secondary metabolites and the Brazilian Atlantic coast and its oceanic islands have been considered as a hotspot for the discovery of new Plakinidae species. Herein, we report the chemical profile among cytotoxic extracts obtained from four species of Plakinidae, collected in Fernando de Noronha Archipelago (PE, Northeastern Brazil). Crude organic extracts of Plakinastrella microspiculifera, Plakortis angulospiculatus, Plakortis insularis, and Plakortis petrupaulensis showed strong antiproliferative effects against two different cancer cell lines (HCT-116: 86.7-100%; MCF-7: 74.9-89.5%) at 50μg/mL, by the MTT assay. However, at a lower concentration (5μg/mL), high variability in inhibition of cell growth was observed (HCT-116: 17.3-68.7%; MCF-7: 0.00-55.5%), even within two samples of Plakortis insularis which were collected in the west and east sides of the Archipelago. To discriminate the chemical profile, the samples were investigated by UHPLC-HRMS under positive ionization mode. The produced data was uploaded to the Global Natural Products Social Molecular Networking and organized based on spectral similarities for purposes of comparison and annotation. Compounds such as dipeptides, nucleosides and derivatives, polyketides, and thiazine alkaloids were annotated and metabolomic differences were perceived among the species.To the best of our knowledge, this is the first assessment for cytotoxic activity and chemical profiling for Plakinastrella microspiculifera, Plakortis insularisand Plakortis petrupaulensis, revealing other biotechnologically relevant members of the Plakinidae family.

MetMax Human Hepatocyte/HEK Cytotoxic Reactive Metabolite Assay as a Potential In Vitro Experimental System for the Identification of DILI Drugs

In drug development, it is important to identify drug candidates where drug metabolism plays key roles in their toxicity. Major reasons for the identification of drug candidates with metabolism-dependent toxicity are as follows: 1. Safety profiles determined in preclinical animal species may not accurately predict human effects due to species difference in drug metabolism; and 2. idiosyncratic drug toxicity may occur in individuals due to enhanced metabolic activation or compromised detoxification. We recently developed a novel in vitro hepatocyte system, the MetMax Human Hepatocyte (MMHH) system with permeabilized human hepatocytes supplemented with metabolic cofactors, for the evaluation of drug metabolism. The permeabilization treatment removes the plasma membrane as a barrier for drug diffusion into the hepatocytes, and the diffusion of the metabolites of the hepatocytes. A further advantage of MMHH is that cytotoxicity of the intended substrate would not affect drug metabolism, a challenge often encountered in the evaluation of metabolism of toxic drugs in intact hepatocytes. We report here the development of the MMHH/HEK assay for the evaluation of metabolic activation and detoxification of toxic drugs. In this assay, drug toxicity is quantified in a drug metabolism incompetent target cell line (HEK293) in the presence of absence of MMHH as an exogenous metabolic activating system, and in the presence of selective cofactors for the evaluation of key metabolic activation and detoxification pathways. As a proof-of-concept study, the MMHH/HEK assay was applied in the the evaluation of the model metabolically-activated drugs that are known to be associated with severe drug induced liver injuries (DILI) - acetaminophen, cyclophosphamide, and troglitazone. Our results showed that the cytotoxicity of these model DILI drugs was enhanced in the presence of MMHH supplemented with NADPH, thereby confirming the role of oxidative metabolism in metabolic activation. Furthermore, supplementation of NADPH with reduced glutathione (GSH), a physiologically relevant detoxifying conjugating cofactor for reactive metabolites, led to significant attenuation of cytotoxicity, demonstrating that these model drugs were metabolized by hepatocytes to to reactive, cytotoxic metabolites. Supplementation with UDPGA and PAPS also attenuated the in vitro cytotoxicity of these model drugs in the MMHH/HEK assay, demonstrating the involvement of glucuronidation and sulfation conjugating pathways in toxification. Troglitazone cytotoxicity in the MMHH/HEK assay was found to be higher than that observed for the known less hepatotoxic analogs, rosiglitazone and pioglitazone. Our results suggest that MMHH/HEK assay can be applied towards the evaluation of metabolic activation and detoxification and the identification of drugs with idiosyncratic DILI potential.

Optimization of PhysicoChemical Parameters for Production of Cytotoxic Secondary Metabolites and Apoptosis Induction Activities in the Culture Extract of a Marine Algal-Derived Endophytic Fungus Aspergillus sp.

The endophytic fungal community in the marine ecosystem has been demonstrated to be relevant source of novel and pharmacologically active secondary metabolites. The current study focused on the evaluation of cytotoxic and apoptosis induction potential in the culture extracts of endophytic fungi associated with Sargassum muticum, a marine brown alga. The cytotoxicity of the four marine endophytes, Aspergillus sp., Nigrospora sphaerica, Talaromyces purpureogenus, and Talaromyces stipitatus, was evaluated by the MTT assay on HeLa cells. Further, several physicochemical parameters, including growth curve, culture media, and organic solvents, were optimized for enhanced cytotoxic activity of the selected extract. The Aspergillus sp. ethyl acetate extract (ASE) showed maximum cytotoxicity on multiple cancer cell lines. Chemical investigation of the metabolites by gas chromatography–mass spectroscopy (GC-MS) showed the presence of several compounds, including quinoline, indole, 2,4-bis(1,1-dimethylethyl) phenol, and hexadecenoic acid, known to be cytotoxic in ASE. The ASE was then tested for cytotoxicity in vitro on a panel of six human cancer cell lines, namely, HeLa (cervical adenocarcinoma), MCF-7 (breast adenocarcinoma), Hep G2 (hepatocellular carcinoma), A-549 (lung carcinoma), A-431 (skin/epidermis carcinoma), and LN-229 (glioblastoma). HeLa cells were most vulnerable to ASE treatment with an IC50 value of 24 ± 2 μg/ml. The mechanism of cytotoxicity exhibited by the ASE was further investigated on Hela cells. The results showed that the ASE was capable of inducing apoptosis in HeLa cells through production of reactive oxygen species, depolarization of mitochondrial membrane, and activation of the caspase-3 pathway, which shows a possible activation of the intrinsic apoptosis pathway. It also arrested the HeLa cells at the G2/M phase of the cell cycle, eventually leading to apoptosis. Through this study, we add to the knowledge about the marine algae associated with fungal endophytes and report its potential for purifying specific compounds responsible for cytotoxicity.

Targeting the metabolic vulnerability of acute myeloid leukemia blasts with a combination of venetoclax and 8-chloro-adenosine

BackgroundBCL‐2 inhibition through venetoclax (VEN) targets acute myeloid leukemia (AML) blast cells and leukemic stem cells (LSCs). Although VEN-containing regimens yield 60–70% clinical response rates, the vast majority of patients inevitably suffer disease relapse, likely because of the persistence of drug-resistant LSCs. We previously reported preclinical activity of the ribonucleoside analog 8-chloro-adenosine (8-Cl-Ado) against AML blast cells and LSCs. Moreover, our ongoing phase I clinical trial of 8-Cl-Ado in patients with refractory/relapsed AML demonstrates encouraging clinical benefit. Of note, LSCs uniquely depend on amino acid-driven and/or fatty acid oxidation (FAO)-driven oxidative phosphorylation (OXPHOS) for survival. VEN inhibits OXPHOS in LSCs, which eventually may escape the antileukemic activity of this drug. FAO is activated in LSCs isolated from patients with relapsed AML.MethodsUsing AML cell lines and LSC-enriched blast cells from pre-treatment AML patients, we evaluated the effects of 8-Cl-Ado, VEN and the 8-Cl-Ado/VEN combination on fatty acid metabolism, glycolysis and OXPHOS using liquid scintillation counting, a Seahorse XF Analyzer and gene set enrichment analysis (GSEA). Western blotting was used to validate results from GSEA. HPLC was used to measure intracellular accumulation of 8-Cl-ATP, the cytotoxic metabolite of 8-Cl-Ado. To quantify drug synergy, we created combination index plots using CompuSyn software. The log-rank Kaplan–Meier survival test was used to compare the survival distributions of the different treatment groups in a xenograft mouse model of AML.ResultsWe here report that VEN and 8-Cl-Ado synergistically inhibited in vitro growth of AML cells. Furthermore, immunodeficient mice engrafted with MV4-11-Luc AML cells and treated with the combination of VEN plus 8-Cl-Ado had a significantly longer survival than mice treated with either drugs alone (p ≤ 0.006). We show here that 8-Cl-Ado in the LSC-enriched population suppressed FAO by downregulating gene expression of proteins involved in this pathway and significantly inhibited the oxygen consumption rate (OCR), an indicator of OXPHOS. By combining 8-Cl-Ado with VEN, we observed complete inhibition of OCR, suggesting this drug combination cooperates in targeting OXPHOS and the metabolic homeostasis of AML cells.ConclusionTaken together, the results suggest that 8-Cl-Ado enhances the antileukemic activity of VEN and that this combination represents a promising therapeutic regimen for treatment of AML.

NIR-II Absorbing Semiconducting Polymer-Triggered Gene-Directed Enzyme Prodrug Therapy for Cancer Treatment.

Exploration of facile strategies for precise regulation of target gene expression remains highly challenging in the development of gene therapies. Especially, a stimuli-responsive nanocarrier integrated with ability of noninvasive remote control for treating wide types of cancers is rarely developed. Herein, a NIR-II absorbing semiconducting polymer (PBDTQ) is employed to remotely activate the heat-inducible heat-shock protein 70 (HSP70) promoter under laser irradiation, further realizing regulation of gene-directed enzyme prodrug therapy (GDEPT) for cancer treatment in mild hyperthermia. In this multifunctional nanocomposite, the PBDTQ and double suicide gene plasmid (pSG) based on HSP70 promoter are incorporated into a lipid complex. Upon NIR-II laser excitation, the mild photothermal effect (≈43 °C) generated from PBDTQ can cause the release of pSG and activation of HSP70 promoter, and then upregulate suicide gene expression triggered by the HSP70 promoter which can further convert the nontoxic prodrug into its cytotoxic metabolites. Therefore, this work demonstrates a universal NIR-II laser-triggered GDEPT using semiconducting polymers as the photothermal generator for cancer treatment with minimized collateral damage and nontargeted side effects.

Discovery of cytotoxic natural products from Red Sea sponges: Structure and synthesis.

Marine ecosystem continues to produce a great wealth of molecules endowed with cytotoxic activity towards a large panel of tumor cells. Marine sponges, apparently defenseless organisms are endowed through evolution with a range of cytotoxic metabolites for self protection against predators and space competition. Interestingly, high biodiversity of sponges with Demospongiae and Calcarea species that have yielded numerous bioactive compounds have been accorded in different regions of the Red Sea. This review for the first time provides a comprehensive overview of 123 cytotoxic agents derived from Red Sea sponges with diverse chemical structures covered till mid 2020 showing activities ranging from mildly active to very active against different panels of cancer cell lines. It has been divided according to the different classes of compounds including alkaloids, terpenoids (sesquiterpenes, diterpenes, triterpenes, sesterterpenes, norsesterterpenes), peptides and macrolides, lipids (steroids, fatty acids/amides and glycerides) etc. The enhancement in the cytotoxicity with respect to the molecular structure changes have been described in detail. We have also accounted for the total synthesis of cytotoxic molecules, subereamolline A, aerothionin, asmarine B, norrsolide and latrunculin B showing interesting activity against different cancer cell lines.

Integrated analytical workflow for chromatographic profiling and metabolite annotation of a cytotoxic Phorbas amaranthus extract

Phorbas is a widely studied genus of marine sponge and produce structurally rich cytotoxic metabolites. Still, only few studies have assessed metabolites present in Brazilian species. To circumvent redundancy, in this work, we applied and herein report the use of a scouting liquid chromatographic system associate to the design of experiment produced by the DryLab® software to obtain a fast and efficient chromatographic separation of the active hexane fraction, further enabling untargeted high-resolution mass spectrometry (HRMS) data. To this end, a crude hydroalcoholic extract of the sponge Phorbas amaranthus collected in Brazilian coast was prepared and partitioned. The cytotoxicity of the crude extract and the fractions was evaluated using tumor cell culture models. Fragmentation pathways assembled from HRMS data allowed the annotation of 18 known Phorbas metabolites, while 17 metabolites were inferred based on Global Natural Product Social Molecular Networking (GNPS), matching with a further 29 metabolites annotated through molecular subnetwork. The workflow employed demonstrates that chromatographic method development can be accelerated by the use of automated scouting systems and DryLab®, which is useful for profiling natural product libraries, as well as data curation by molecular clusters and should be incorporated to the tools of natural product chemists.

The Hypoxia-Activated Prodrug TH-302: Exploiting Hypoxia in Cancer Therapy.

Hypoxia is an important feature of most solid tumors, conferring resistance to radiation and many forms of chemotherapy. However, it is possible to exploit the presence of tumor hypoxia with hypoxia-activated prodrugs (HAPs), agents that in low oxygen conditions undergo bioreduction to yield cytotoxic metabolites. Although many such agents have been developed, we will focus here on TH-302. TH-302 has been extensively studied, and we discuss its mechanism of action, as well as its efficacy in preclinical and clinical studies, with the aim of identifying future research directions.

Metabolic profiling of cytotoxic metabolites from five Tabebuia species supported by molecular correlation analysis

Tabebuia is the largest genus among the family Bignoniaceae. Tabebuia species are known for their high ornamental and curative value. Here, the cytotoxic potential of extracts from the leaves and stems of five Tabebuia species was analyzed. The highest activity was observed for T. rosea (Bertol.) DC. stem extract against HepG2 cell line (IC50 4.7 µg/mL), T. pallida L. stem extract against MCF-7 cell line (IC50 6.3 µg/mL), and T. pulcherrima stem extract against CACO2 cell line (IC50 2.6 µg/mL). Metabolic profiling of the ten extracts using liquid chromatography–high-resolution mass spectrometry for dereplication purposes led to annotation of forty compounds belonging to different chemical classes. Among the annotated compounds, irridoids represent the major class. Principle component analysis (PCA) was applied to test the similarity and variability among the tested species and the score plot showed similar chemical profiling between the leaves and stems of both T. pulcherrima and T. pallida L. and unique chemical profiling among T. rosea (Bertol.) DC., T. argentea Britton, and T. guayacan (Seem.) Hemsl. leaf extracts and the stem extract of T. rosea (Bertol.) DC. Additionally, a molecular correlation analysis was used to annotate the bioactive cytotoxic metabolites in the extracts and correlate between their chemical and biological profiles.

Pt(IV) Prodrugs with NSAIDs as Axial Ligands

A chemo-anti-inflammatory strategy is of interest for the treatment of aggressive cancers. The platinum (IV) prodrug with non-steroidal anti-inflammatory drugs (NSAIDs) as axial ligands is designed to efficiently enter tumor cells due to high lipophilicity and release the cytotoxic metabolite and NSAID intracellularly, thereby reducing side effects and increasing the therapeutic efficacy of platinum chemotherapy. Over the last 7 years, a number of publications have been devoted to the design of such Pt(IV) prodrugs in combination with anti-inflammatory chemotherapy, with high therapeutic efficacy in vitro and In vivo. In this review, we summarize the studies devoted to the development of Pt(IV) prodrugs with NSAIDs as axial ligands, the study of the mechanism of their cytotoxic action and anti-inflammatory activity, the structure–activity ratio, and therapeutic efficacy.

Neurobiology of Schizophrenia (to the Construction of Clinical and Biological Model)

The objective: of the study was to present the main provisions of a new clinical and biological model of schizophrenia, which establishes links between disorders in the field of biological processes and the formation of positive and negative in the general psychopathological space of schizophrenia on the basis of the analysis of long-term results of clinical and biological research of the Mental Health Research Centre.Material and method: by keywords “schizophrenia”, “biological hypotheses of schizophrenia”, “neuroinflammation”, “neurodegeneration”; “positive disorders”, “negative disorders”, “neuroimmune relationships”, “catabolismof tryptophan”, “activation of microglia”, publications from PubMed/MEDLINE databases, RSCI and other sources were analyzedover the past 10 years in comparison with the results of clinical and biological studies of schizophrenia at the Mental Health Science Center.Results: comparison and analysis of current biological hypotheses of schizophrenia indicates that immunological studies are the most promising for solving the problem of establishing links between disorders of neurobiological processes and psychopathological specificities of schizophrenia. Within the framework of the new clinical and biological model, a key role is assigned to the process of neuroinflammation, which determines the pathogenesis of both negative and positive disorders by various, albeit interrelated, molecular mechanisms. One of these mechanisms, associated with the development of reversible positive symptom complexes, is based on an imbalance in the neurotransmitter systems, which is formed as a result of the effect of proinflammatory cytokines on tryptophan catabolism. Another mechanism that determines the development of negative symptom complexes is associated with the influence of cytotoxic metabolites on the processes of neurodegeneration. Conclusion: a new clinical and biological model of schizophrenia establishes a paradigm of the relationship between disorders in the sphere of biological processes determined by neuroinflammation/inflammation and the formation of the main procedural dimensions — positive and negative disorders in the general psychopathological space of schizophrenia. This model makes it possible to clarify some general provisions related to the pharmacotherapy of schizophrenia and the relief of negative disorders, and also serves as the basis for the development of new approaches to early diagnosis, clinical and social prognosis.

Biodiversity, Bioactivity, and Metabolites of High Desert Derived Oregonian Soil Bacteria.

From arid, high desert soil samples collected near Bend, Oregon, 19 unique bacteria were isolated. Each strain was identified by 16S rRNA gene sequencing, and their organic extracts were tested for antibacterial and antiproliferative activities. Noteworthy, six extracts (30 %) exhibited strong inhibition resulting in less than 50 % cell proliferation in more than one cancer cell model, tested at 10 μg/mL. Principal component analysis (PCA) of LC/MS data revealed drastic differences in the metabolic profiles found in the organic extracts of these soil bacteria. In total, fourteen potent antibacterial and/or cytotoxic metabolites were isolated via bioactivity-guided fractionation, including two new natural products: a pyrazinone containing tetrapeptide and 7-methoxy-2,3-dimethyl-4H-chromen-4-one, as well as twelve known compounds: furanonaphthoquinone I, bafilomycin C1 and D, FD-594, oligomycin A, chloramphenicol, MY12-62A, rac-sclerone, isosclerone, tunicamycin VII, tunicamycin VIII, and (6S,16S)-anthrabenzoxocinone 1.264-C.

CMPK1 Regulated by miR-130b Attenuates Response to 5-FU Treatment in Gastric Cancer.

Gastric cancer (GC) remains a major world-wide challenge, especially in Asian countries. Chemotherapy with 5-fluorouracil (5-FU) and cisplatin is used as the first-line treatment and development of chemoresistance is a major cause of progression. UMP/CMP kinase is responsible for the phosphorylation of the ribonucleotide metabolite 5-fluoro-5′-monophosphate (FUMP) in 5-FU metabolic process, and recognized as a key step in the conversion of 5-FU to cytotoxic metabolites. Our bioinformatics analysis and molecular experiments demonstrated that high expression of CMPK1 was associated with prolonged survival and response to 5-FU treatment in GC samples. Further analysis demonstrated that miR-130b as a key epigenetic regulator of CMPK1, and miR-130b-mediated attenuation of CMPK1 resulted in resistance of gastric cancer cells to DNA damage and cell death after treatment with 5-FU. Rescue experiments with augmented CMPK1 expression abolished the effect of miR-130b demonstrating the key function of this miRNA in this pathway. Thus, this newly identified miR-130b-CMPK1 axis suggests a potentially new chemotherapeutic strategy for improved response to 5-FU therapy.