Chemical Proteomics and Phenotypic Profiling Identifies the Aryl Hydrocarbon Receptor as a Molecular Target of the Utrophin Modulator Ezutromid

Duchenne muscular dystrophy (DMD) is a fatal muscle-wasting disease arising from mutations in the dystrophin gene. Upregulation of utrophin to compensate for the missing dystrophin offers a potential therapy independent of patient genotype. The first-in-class utrophin modulator ezutromid/SMT C1100 was developed from a phenotypic screen through to a Phase 2 clinical trial. Promising efficacy and evidence of target engagement was observed in DMD patients after 24 weeks of treatment, however trial endpoints were not met after 48 weeks. The objective of this study was to understand the mechanism of action of ezutromid which could explain the lack of sustained efficacy and help development of new generations of utrophin modulators. Using chemical proteomics and phenotypic profiling we show that the aryl hydrocarbon receptor (AhR) is a target of ezutromid. Several lines of evidence demonstrate that ezutromid binds AhR with an apparent KD of 50 nm and behaves as an AhR antagonist. Furthermore, other reported AhR antagonists also upregulate utrophin, showing that this pathway, which is currently being explored in other clinical applications including oncology and rheumatoid arthritis, could also be exploited in future DMD therapies.

Exogenous IGF-1 improves cognitive function in rats with high-fat diet consumption

Insulin-like growth factor-1 (IGF-1) improves cognitive function, but its mechanism has not been elucidated. The aim of the study was to explore whether IGF-1 exerted its protective effect on cognitive function and anxiety behavior through the activation of PI3K/Akt/CREB pathway in high-fat diet rats. Neuronal cells HT22 were treated with nothing, IGF-1, IGF-1 + LY294002 or IGF-1 + 666-15. Expressions of p-PI3K, p-Akt and p-CREB were measured using Western blot analysis. Thirty C57BL/6J rats were used. After feeding with high-fat diet, normal saline, PEG-IGF-1, PEG-IGF-1 + LY294002 or PEG-IGF-1 + 666-15 was treated. Cognitive function and anxiety behavior were assessed by Morris water maze and open field test. Several inflammation and oxidative stress biomarkers were measured using recognized methods. Expressions of p-PI3K and p-CREB were also measured using Western blot analysis. After IGF-1 treatment in cells, expressions of p-PI3K, p-Akt and p-CREB were increased. Furthermore, LY294002 downregulated the expressions of these three proteins, but 666-15 only inhibited the expression of CREB in the cells. Compared with the control rats, we found abnormalities of cognitive function and anxiety behavior, inhibition of PI3K/Akt/CREB pathway and increase of oxidative stress and inflammation in high-fat diet rats. After PEG-IGF-1 treatment, the changes in high-fat diet rats were reversed. Then, we blocked the pathway and found that these blockers attenuated the protective effects of PEG-IGF-1. In conclusion, IGF-1 improved cognitive function and anxiety behavior in high-fat diet rats and inhibited inflammation and oxidative stress in hippocampus tissue through the activation of PI3K/Akt/CREB pathway.

Treatment with Cannabinoids as a Promising Approach for Impairing Fibroblast Activation and Prostate Cancer Progression

Endo-, phyto- and synthetic cannabinoids have been proposed as promising anti-cancer agents able to impair cancer cells’ behavior without affecting their non-transformed counterparts. However, cancer outcome depends not only on cancer cells’ activity, but also on the stromal cells, which coevolve with cancer cells to sustain tumor progression. Here, we show for the first time that cannabinoid treatment impairs the activation and the reactivity of cancer-associated fibroblasts (CAFs), the most represented stromal component of prostate tumor microenvironment. Using prostate cancer-derived CAFs, we demonstrated that WIN 55-212.2 mesylate, a synthetic full agonist of cannabinoid receptors (CBs) 1 and 2, downregulates α-smooth muscle actin and matrix metalloprotease-2 expression, and it inhibits CAF migration, essential features to ensure the activated and reactive CAF phenotype. Furthermore, by impairing stromal reactivity, WIN 55-212.2 mesylate also negatively affects CAF-mediated cancer cells’ invasiveness. Using selective antagonists of CBs, we proved that CAFs response to WIN 55-212.2 mesylate is mainly mediated by CB₂. Finally, we suggest that endocannabinoids self-sustain both prostate tumor cells migration and CAFs phenotype by an autocrine loop. Overall, our data strongly support the use of cannabinoids as anti-tumor agents in prostate cancer, since they are able to simultaneously strike both cancer and stromal cells.

P38 MAPK and glucocorticoid receptor crosstalk in bronchial epithelial cells

Abstract

p38 MAPK inhibition may have additive and synergistic anti-inflammatory effects when used with corticosteroids. We investigated crosstalk between p38 MAPK inhibitors and corticosteroids in bronchial epithelial cells to investigate synergistic effects on cytokine production and the molecular mechanisms involved. Effects of the p38 MAPK inhibitor BIRB-796 and dexamethasone alone and in combination on LPS, polyI:C or TNFα -induced IL-6, CXCL8 and RANTES were assessed in 16HBEs (human epithelial cell line) and on TNFα-induced IL-6 and CXCL8 in primary human epithelial cells from asthma patients and healthy controls. 16HBEs were used to assess effects of BIRB-796 alone and in combination with dexamethasone on glucocorticoid receptor (GR) activity by reporter gene assay, expression of GR target genes and nuclear localisation using Western blot. The effects of BIRB-796 on TNFα stimulated phosphorylation of p38 MAPK and GR at serine (S) 226 by Western blot. Epithelial levels of phosphorylated p38 MAPK and GR S226 were determined by immunohistochemistry in bronchial biopsies from asthma patients and healthy controls. BIRB-796 in combination with dexamethasone increased inhibition of cytokine production in a synergistic manner. Combination treatment significantly increased GR nuclear localisation compared to dexamethasone alone. BIRB-796 inhibited TNFα-induced p38 MAPK and GR S226 phosphorylation. Phosphorylated GR S226 and p38 MAPK levels were increased in bronchial epithelium of more severe asthma patients. Molecular crosstalk exists between p38 MAPK activation and GR function in human bronchial epithelial cells, which alters GR activity. Combining a p38 MAPK inhibitor and a corticosteroid may demonstrate therapeutic potential in severe asthma.

Key messages

• Combination of corticosteroid and p38 inhibitor in human bronchial epithelial cells

• Combination increased cytokine inhibition synergistically and nuclear GR

• p38 MAPK inhibition reduced TNFα-induced phosphorylation of GR at S226 but not S211

• Phosphorylated GRS226 and p38 is increased in bronchial epithelium in severe asthma

• Combining a p38 inhibitor and a corticosteroid may be effective in asthma treatment

Electronic supplementary material

The online version of this article (10.1007/s00109-020-01873-3) contains supplementary material, which is available to authorized users.

Altertoxins with Quorum Sensing Inhibitory Activities from The Marine-Derived Fungus Cladosporium sp. KFD33

Five new perylenequinone derivatives, altertoxins VIII–XII (1–5), as well as one known compound cladosporol I (6), were isolated from the fermentation broth of the marine-derived fungus Cladosporium sp. KFD33 from a blood cockle from Haikou Bay, China. Their structures were determined based on spectroscopic methods and ECD spectra analysis along with quantum ECD calculations. Compounds 1–6 exhibited quorum sensing inhibitory activities against Chromobacterium violaceum CV026 with MIC values of 30, 30, 20, 30, 20 and 30 μg/well, respectively.

Calcium-sensing receptor promotes tumor proliferation and migration in human intrahepatic cholangiocarcinoma by targeting ERK signaling pathway

The Calcium-sensing receptor (CaSR) is functionally expressed in the biliary epithelial cells and it has been verified to possess various regulatory functions in several different forms of human cancers. But its pathological role in human intrahepatic cholangiocarcinoma (ICC) development remains obscure. Here, we confirmed that CaSR expression was up-regulated in ICC tumor specimens and cell lines, which was positively correlated with number of tumors, lymph node metastasis and poor prognosis of ICC patients. CaSR activation induced by CaCl₂ or Calindol (a selective CaSR agonist) markedly facilitated cell proliferation and migration in ICC cells, while knockdown of CaSR or NPS2143 treatment (a CaSR antagonist) dramatically suppressed the above effects. We also demonstrated that alteration of CaSR activity mediated tumorigenesis and growth of ICC in vivo. Mechanistically, CaSR activation could promote cell cycle progression and induce an upregulation of MMP-2 and MMP-9 expression partly via the simulation of ERK1/2 signaling pathway. And further inhibition of ERK pathway significantly suppressed ICC cell viability and migration capacity. Together, our findings shed novel light on the role of CaSR as an oncogene in ICC progression and indicated that modulation of CaSR might serve as a preventive or therapeutic strategy for ICC.

Antistress and antidepressant properties of dapoxetine and vortioxetine

The studies aimed to determine the antidepressant efficacy of single and chronic administration of dapoxetine alone and vortioxetine alone, as well as in the combination of these drugs. An additional objective of the study was to measure the effect of the active substances on the corticosterone level in chronically stressed animals. The study was conducted on male Wistar rats using non‑stressed and stressed groups (chronic restraint stress). The experiment comprised both forced swimming test (immobility time test) and corticosterone level measurement using Corticosterone ELISA Kit. The obtained results confirm the antidepressant efficacy of used drugs upon both single and chronic administration and potential efficacy of these drugs administered in combination with stressed rats. Corticosterone level analysis, meanwhile, showed stress relieving properties of the study drugs, which reduced the animal stress hormone level, whether administered separately or in combination. Dapoxetine and vortioxetine have an antidepressant and stress relieving effect on rats subject to chronic stress both in monotherapy and in combined therapy. Because both study drugs are new additions on the market, further research is necessary to prevent interactions related, for instance, with uncontrolled use of two drugs with similar mechanisms of action but prescribed in different indications (dapoxetine is commonly used to treat premature ejaculation).

Calcium-sensing receptor regulates intestinal dipeptide absorption via Ca2+ signaling and IKCa activation

Although absorption of di- and tripeptides into intestinal epithelial cells occurs via the peptide transporter 1 (PEPT1, also called solute carrier family 15 member 1 (SLC15A1)), the detailed regulatory mechanisms are not fully understood. We examined: (a) whether dipeptide absorption in villous enterocytes is associated with a rise in cytosolic Ca2+ ([Ca2+ ]cyt ), (b) whether the calcium sensing receptor (CaSR) is involved in dipeptide-elicited [Ca2+ ]cyt signaling, and (c) what potential consequences of [Ca2+ ]cyt signaling may enhance enterocyte dipeptide absorption. Dipeptide Gly-Sar and CaSR agonist spermine markedly raised [Ca2+ ]cyt in villous enterocytes, which was abolished by NPS-2143, a selective CaSR antagonist and U73122, an phospholipase C (PLC) inhibitor. Apical application of Gly-Sar induced a jejunal short-circuit current (Isc), which was reduced by NPS-2143. CaSR expression was identified in the lamina propria and on the basal enterocyte membrane of mouse jejunal mucosa in both WT and Slc15a1-/- animals, but Gly-Sar-induced [Ca2+ ]cyt signaling was significantly decreased in Slc15a1-/- villi. Clotrimazole and TRM-34, two selective blockers of the intermediate conductance Ca2+ -activated K+ channel (IKCa ), but not iberiotoxin, a selective blocker of the large-conductance K+ channel (BKCa ) and apamin, a selective blocker of the small-conductance K+ channel (SKCa ), significantly inhibited Gly-Sar-induced Isc in native tissues. We reveal a novel CaSR-PLC-Ca2+ -IKCa pathway in the regulation of small intestinal dipeptide absorption, which may be exploited as a target for future drug development in human nutritional disorders.

Seviteronel, a Novel CYP17 Lyase Inhibitor and Androgen Receptor Antagonist, Radiosensitizes AR-Positive Triple Negative Breast Cancer Cells

Increased rates of locoregional recurrence (LR) have been observed in triple negative breast cancer (TNBC) despite multimodality therapy, including radiation (RT). Recent data suggest inhibiting the androgen receptor (AR) may be an effective radiosensitizing strategy, and AR is expressed in 15-35% of TNBC tumors. The aim of this study was to determine whether seviteronel (INO-464), a novel CYP17 lyase inhibitor and AR antagonist, is able to radiosensitize AR-positive (AR+) TNBC models. In cell viability assays, seviteronel and enzalutamide exhibited limited effect as a single agent (IC50 > 10 μM). Using clonogenic survival assays, however, AR knockdown and AR inhibition with seviteronel were effective at radiosensitizing cells with radiation enhancement ratios of 1.20-1.89 in models of TNBC with high AR expression. AR-negative (AR-) models, regardless of their estrogen receptor expression, were not radiosensitized with seviteronel treatment at concentrations up to 5 μM. Radiosensitization of AR+ TNBC models was at least partially dependent on impaired dsDNA break repair with significant delays in repair at 6, 16, and 24 h as measured by immunofluorescent staining of γH2AX foci. Similar effects were observed in an in vivo AR+ TNBC xenograft model where there was a significant reduction in tumor volume and a delay to tumor doubling and tripling times in mice treated with seviteronel and radiation. Following combination treatment with seviteronel and radiation, increased binding of AR occurred at DNA damage response genes, including genes involved both in homologous recombination and non-homologous end joining. This trend was not observed with combination treatment of enzalutamide and RT, suggesting that seviteronel may have a different mechanism of radiosensitization compared to other AR inhibitors. Enzalutamide and seviteronel treatment also had different effects on AR and AR target genes as measured by immunoblot and qPCR. These results implicate AR as a mediator of radioresistance in AR+ TNBC models and support the use of seviteronel as a radiosensitizing agent in AR+ TNBC.

Naphtho-Gamma-Pyrones Produced by Aspergillus tubingensis G131: New Source of Natural Nontoxic Antioxidants

Seven naphtho-gamma-pyrones (NγPs), including asperpyrone E, aurasperone A, dianhydroaurasperone C, fonsecin, fonsecinone A, fonsecin B, and ustilaginoidin A, were isolated from Aspergillus tubingensis G131, a non-toxigenic strain. The radical scavenging activity of these NγPs was evaluated using ABTS assay. The Trolox equivalent antioxidant capacity on the seven isolated NγPs ranged from 2.4 to 14.6 μmol L^-1. The toxicity and ability of the NγPs to prevent H₂O₂-mediated cell death were evaluated using normal/not cancerous cells (CHO cells). This cell-based assay showed that NγPs: (1) Are not toxic or weakly toxic towards cells and (2) are able to protect cells from oxidant injuries with an IC₅₀ on H₂O₂-mediated cell death ranging from 2.25 to 1800 μmol mL^-1. Our data show that A. tubingensis G131 strain is able to produce various NγPs possessing strong antioxidant activities and low toxicities, making this strain a good candidate for antioxidant applications in food and cosmetic industries.

The α7 nicotinic acetylcholine receptor positive allosteric modulator prevents lipopolysaccharide-induced allodynia, hyperalgesia and TNF-α in the hippocampus in mice

BACKGROUND

Previous studies have shown that α7 nicotinic acetylcholine receptor (nAChR) has a critical role in the regulation of pain sensitivity and neuroinflammation. However, pharmacological effects of α7 nAChR activation in the hippocampus on neuroinflammatory mechanisms associated with allodynia and hyperalgesia remain unknown. We have determined the effects of 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide (TQS), an α7 nAChR positive allosteric modulator, on lipopolysaccharide (LPS)-induced allodynia and hyperalgesia in mice. We also evaluated the effects of TQS on immunoreactivity of microglial marker ionized-calcium binding adaptor molecule 1 (Iba-1), phospho-nuclear factor-κB (p-NF-κB p65), tumor necrosis factor-alpha (TNF-α), and norepinephrine (NE) level.

METHODS

Mice were treated with (0.25, 1 or 4 mg/kg, ip) followed by LPS (1 mg/kg, ip) administration. Allodynia and hyperalgesia were determined using von Frey filaments and hot plate respectively. Immunoreactivity of Iba-1, p-NF-κB p65, and TNF-α, were measured in the hippocampus using immunofluorescence assay. Hippocampal NE level was evaluated using high performance liquid chromatography.

RESULTS

LPS administration resulted in allodynia and hyperalgesia in mice after six h. Systemic administration of TQS prevented LPS-induced allodynia and hyperalgesia. TQS pretreatment significantly decreased the immunoreactivity of Iba-1, p-NF-κB, and TNF-α in CA1 and DG regions of the hippocampus. In addition, TQS reversed LPS-induced NE reduction in the hippocampus.

CONCLUSIONS

Taken together, our results suggest that TQS prevented LPS-induced allodynia and hyperalgesia, upregulation of TNF-α expression and NE level reduction involving microglial α7 nAChR in part in the hippocampus. Therefore, these findings highlight the important effects of α7 nAChR allosteric modulator against symptoms of inflammatory pain.

A Near-Complete Series of Four Atropisomeric Jozimine A2-Type Naphthylisoquinoline Dimers with Antiplasmodial and Cytotoxic Activities and Related Alkaloids from Ancistrocladus abbreviatus

Three new naphthylisoquinoline dimers, jozibrevines A-C (1a-c), were isolated from the West African shrub Ancistrocladus abbreviatus, along with the known dimer jozimine A₂ (1d). The two molecular moieties of 1a-d are coupled via the sterically constrained 3',3″-positions of their two naphthalene units, so that the central biaryl linkage is rotationally hindered. With the two outer axes also being chiral, 1a-d possess three consecutive stereogenic axes. The four isolated dimers all have the same constitutions and identical absolute configurations at the four stereogenic centers, but differ by their axial chirality. They belong to the extremely small class of Dioncophyllaceae-type naphthylisoquinoline dimers, i.e., being devoid of oxygen functions at C-6 and bearing the R-configuration at C-3 in their isoquinoline portions. Besides these dimers, the plant produces predominantly typical Ancistrocladaceae-type monomeric compounds, i.e., with the S-configuration at C-3 and an oxygen function at C-6, such as the new ancistrobrevines K (5) and L (6). Furthermore, a new hybrid-type (i.e., mixed Ancistrocladaceae/Dioncophyllaceae-type) alkaloid was identified, named ancistrobrevine M (7), which is 3R-configured and 6-oxygenated. Remarkable was the discovery of its "inverse hybrid-type" counterpart, dioncoline A (8). It is the as yet only known 3S-configured naphthylisoquinoline lacking an O-functionality at C-6. The new jozibrevines A-C (1a-c) exhibited pronounced antiplasmodial activities in the submicromolar range, with 1a being the most potent compound (IC₅₀, 0.012 μM). Furthermore, jozimine A₂ (1d) showed cytotoxicity against human colon carcinoma (HT-29), fibrosarcoma (HT1080), and multiple myeloma (MM.1S) cancer cells, displaying IC₅₀ values of 12.0, 9.0, and 5.0 μM, respectively, whereas jozibrevines A (1a) and B (1b) were nontoxic in this concentration range.

Ealamines A-H, a Series of Naphthylisoquinolines with the Rare 7,8'-Coupling Site, from the Congolese Liana Ancistrocladus ealaensis, Targeting Pancreatic Cancer Cells

From the twigs and leaves of the Central African liana Ancistrocladus ealaensis (Ancistrocladaceae), a series of ten 7,8'-coupled naphthylisoquinoline alkaloids were isolated, comprising eight new compounds, named ealamines A-H (4a, 4b, 5-10), and two known ones, 6-O-demethylancistrobrevine A (11) and yaoundamine A (12), which had previously been found in related African Ancistrocladus species. Only one of the new compounds within this series, ealamine H (10), is a typical Ancistrocladaceae-type alkaloid, with 3S-configuration at C-3 and an oxygen function at C-6, whereas seven of the new alkaloids are the first 7,8'-linked "hybrid-type" naphthylisoquinoline alkaloids, i.e., 3R-configured and 6-oxygenated in the tetrahydroisoquinoline part. The discovery of such a broad series of 7,8'-coupled naphthyltetrahydroisoquinolines is unprecedented, because representatives of this subclass of alkaloids are normally found in Nature quite rarely. The stereostructures of the new ealamines were assigned by HRESIMS, 1D and 2D NMR, oxidative degradation, and experimental and quantum-chemical ECD investigations, and-in the case of ealamine A (4a)-also confirmed by X-ray diffraction analysis. Ealamines A-D exhibited distinct-and specific-antiplasmodial activities, and they displayed pronounced preferential cytotoxic effects toward PANC-1 human pancreatic cancer cells in nutrient-deprived medium, without causing toxicity under normal, nutrient-rich conditions, with ealamine C (5) as the most potent agent.

BIBR1532, a Selective Telomerase Inhibitor, Enhances Radiosensitivity of Non-Small Cell Lung Cancer Through Increasing Telomere Dysfunction and ATM/CHK1 Inhibition

PURPOSE

Telomerase is reactivated in non-small cell lung cancer (NSCLC), and it increases cell resistance to irradiation through protecting damaged telomeres and enhancing DNA damage repair. We investigated the radiosensitizing effect of BIBR1532, a highly selective telomerase inhibitor, and its corresponding mechanism in NSCLC.

METHODS AND MATERIALS

Cell proliferation, telomerase activity, and telomere dysfunction-induced foci were measured with CCK-8 assay, real-time fluorescent quantitative polymerase chain reaction, and immunofluorescence. The effect of BIBR1532 on the response of NSCLC cells to radiation was analyzed using clonogenic survival and xenograft tumor assays. Cell death and cell senescence induced by BIBR1532 or ionizing radiation (IR), or both, were detected with western blotting, flow cytometry, and senescence-association β-galactosidase staining assay.

RESULTS

We observed dose-dependent direct cytotoxicity of BIBR1532 at relatively high concentrations in NSCLC cells. Low concentrations of BIBR1532 did not appear toxic to NSCLC cells; however, they substantially increased the therapeutic efficacy of IR in vitro by enhancing IR-induced apoptosis, senescence, and mitotic catastrophe. Moreover, in a mouse xenograft model, BIBR1532 treatment synergized with IR at nontoxic dose levels promoted the antitumor efficacy of IR without toxicity to hematologic and internal organs. Mechanistically, lower concentrations of BIBR1532 effectively inhibited telomerase activity and increased IR-induced telomere dysfunction, resulting in disruption of chromosomal stability and inhibition of the ATM/CHK1 (ataxia-telangiectasia-mutated/Checkpoint kinase 1) pathway, which impaired DNA damage repair.

CONCLUSIONS

Our findings demonstrate that disturbances in telomerase function by nontoxic dose levels of BIBR1532 effectively enhance the radiosensitivity of NSCLC cells. This finding provides a rationale for the clinical assessment of BIBR1532 as a radiosensitizer.

Histone deacetylase inhibitor CG200745 ameliorates high-fat diet-induced hypertension via inhibition of angiotensin II production

Obesity is growing rapidly worldwide due to consumption of westernized diet and lack of exercise. Obesity is one of the major risk factors of hypertension. The novel histone deacetylase (HDAC) inhibitor CG200745 was originally developed to treat various cancers. Previous studies showed that CG200745 attenuated hypertension through inhibition of cardiac hypertrophy and fibrosis in deoxycorticosterone acetate-induced hypertensive rat. The purpose of this study is to investigate the role and underlying mechanism of CG200745 in high-fat diet (HFD)-induced hypertension. Nine-week old C57BL/6 mice were fed a normal diet (ND) or HFD for 17 weeks. Each group of mice was treated with vehicle or CG200745 by intraperitoneal injection for 9 days. HFD group showed higher body weight, blood pressure (BP), HDAC activities, angiotensinogen and renin expressions in kidney, angiotensin-converting enzyme (ACE) expression in the lung, serum angiotensin II (Ang II) concentration, and myosin light chain₂₀ (MLC₂₀) phosphorylation in mesenteric artery compared with ND group. CG200745 lowered BP, HDAC activity, renin and angiotensinogen in the kidney, ACE in the lung, serum Ang II level, and phosphorylation of MLC₂₀ in HFD group. In conclusion, CG200745 ameliorated HFD-induced hypertension through inhibition of HDAC/Ang II/vascular contraction axis. Our results offer CG200745 as a novel therapeutic option for HFD-induced hypertension.

Sparticolins A-G, Biologically Active Oxidized Spirodioxynaphthalene Derivatives from the Ascomycete Sparticola junci

To explore the chemical diversity of metabolites from new species of Dothideomycetes, the ex-type strain of Sparticola junci was investigated. Seven highly oxygenated and functionalized spirodioxynaphthalene natural products incorporating carboxyalkylidene-cyclopentanoid (1-4), carboxyl-functionalized oxabicyclo[3.3.0]octane (5-6), and annelated 2-cyclopentenone/δ-lactone (7) units, sparticolins A-G, were isolated from submerged cultures of the fungus. Their chemical structures including their relative (and absolute) configurations were established through spectroscopic and X-ray crystallographic analyses. Sparticolin B (2) exhibited inhibitory activity against the Gram-positive bacteria Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus, while sparticolin G (7) showed antifungal activities against Schizosaccharomyces pombe and Mucor hiemalis. All other sparticolins were only weakly active against S. aureus and also showed weak activities against the nematode Caenorhabditis elegans. Compounds 2 and 7 also showed moderate cytotoxic activities against seven mammalian cell lines.

Calcium-sensing receptor bridges calcium and telomerase reverse transcriptase in gastric cancers via Akt

PURPOSE

Human telomerase reverse transcriptase (hTERT) and calcium-sensing receptor (CaSR) act as an oncogene in gastric cancers, however, their relationship in the progression of gastric cancers is yet to be elucidated. Herein, we aimed to access the potential interaction between hTERT and CaSR in the development of gastric cancers.

METHODS

The clinical data of 41 patients with gastric cancers were analyzed regarding the expressions of hTERT and CaSR by immunohistochemistry. Among them, five patients' specimens were also analyzed by Western blotting. The regulation of calcium on the expression level of hTERT and the possible underlying mechanism via CaSR were explored in gastric cancer cell lines MKN45 and SGC-7901.

RESULTS

Both hTERT and CaSR were increased and positively correlated in human gastric cancers, which also occurs in gastric cancer cells MKN45 and SGC-7901. Calcium induced hTERT expression at the transcriptional level in a CaSR-dependent manner followed by an increase in telomerase activity, as either a CaSR shRNA or the CaSR antagonist NPS2143 abolished the calcium-mediated regulation of hTERT and telomerase activity. Further studies showed that CaSR-mediated cytosolic calcium rise followed by Akt activation was involved in the regulation of hTERT by extracellular calcium. Finally, neither CaSR overexpression nor shRNA-mediated CaSR downregulation had an effect on the expression level of hTERT.

CONCLUSIONS

Our findings established a functional linkage between CaSR and hTERT in the development of gastric cancers and CaSR-hTERT coupling might serve as a novel target for therapeutic strategy against human gastric cancers.

Antiproliferative activity of (R)-4'-methylklavuzon on hepatocellular carcinoma cells and EpCAM+/CD133+ cancer stem cells via SIRT1 and Exportin-1 (CRM1) inhibition

Cytotoxic effects of (R)-4'-methylklavuzon were investigated on hepatocellular carcinoma cells (HuH-7 and HepG2) and HuH-7 EpCAM+/CD133+ cancer stem cells. IC50 of (R)-4'-methylklavuzon was found as 1.25 μM for HuH-7 parental cells while it was found as 2.50 μM for HuH-7 EpCAM+/CD133+ cancer stem cells. (R)-4'-methylklavuzon tended to show more efficient in vitro cytotoxicity with its lower IC50 values on hepatocellular carcinoma cell lines compared to its lead molecule, goniothalamin and FDA-approved drugs, sorafenib and regorafenib. Cell-based Sirtuin/HDAC enzyme activity measurements revealed that endogenous Sirtuin/HDAC enzymes were reduced by 40% compared to control. SIRT1 protein levels were upregulated indicating triggered DNA repair mechanism. p53 was overexpressed in HepG2 cells. (R)-4'-methylklavuzon inhibited CRM1 protein providing increased retention of p53 and RIOK2 protein in the nucleus. HuH-7 parental and EpCAM+/CD133+ cancer stem cell spheroids lost intact morphology. 3D HepG2 spheroid viabilities were decreased in a correlation with upregulation in p53 protein levels.

High-affinity sigma-1 (σ1) receptor ligands based on the σ1 antagonist PB212

Aim: The σ1 receptor is a druggable target involved in many physiological processes and diseases. To clarify its physiology and derive therapeutic benefit, nine analogs based on the σ1 antagonist PB212 were synthesized replacing the 4-methylpiperidine with basic moieties of varying size and degree of conformational freedom. Results & methodology: 3-Phenylpyrrolidine, 4-phenylpiperidine or granatane derivatives displayed the highest affinity (Ki.#x00A0;= 0.12, 0.31 or 1.03 nM). Calcium flux assays in MCF7σ1 cells indicated that the highest σ1 receptor affinity are σ1 antagonists. Molecular models provided a structural basis for understanding the σ1 affinity and functional activity of the analogs and incorporated Glennon's σ1 pharmacophore model. Conclusion: Herein, we identify new compounds exploitable as therapeutic drug leads or as tools to study σ1 receptor physiology.

Enantioselectivity and allelopathy both have effects on the inhibition of napropamide on Echinochloa crus-galli

Napropamide is a chiral acetamide herbicide commonly applied to control Echinochloa crus-galli in maize. The inhibition effect may be enantioselective for Echinochloa crus-galli and maize. It may also be affected by the potential allelopathy at field condition. To investigate this, we have examined the inhibition effect of napropamide on Echinochloa crus-galli mono-cultured or co-cultured with maize at field conditions. Our results on morphology, physiology, chlorophyll content and chlorophyll fluorescence suggest that R-napropamide has stronger inhibitory effect than Rac-napropamide and S-napropamide on Echinochloa crus-galli, while none of them affects maize. We found that both glutathione-S-transferase (GST) genes and oxidative enzymes (superoxide dismutase, malondialdehyde) played roles in the inhibition. Accumulations of napropamide in Echinochloa crus-galli were more prominent in roots than in shoots, and no enantioselectivity was found in medium dissipation. We have observed relative allelopathy when applying napropamide to Echinochloa crus-galli co-cultured with maize. The results warrant further field studies on the enantioselectivity and allelopathy of herbicides.

A 3-(4-nitronaphthen-1-yl) amino-benzoate analog as a bifunctional AKR1C3 inhibitor and AR antagonist: Head to head comparison with other advanced AKR1C3 targeted therapeutics

Drugs used for the treatment of castration resistant prostate cancer (CRPC) include Abiraterone acetate (Zytiga®) and Enzalutamide (XTANDI®). However, these drugs provide clinical benefit in metastatic disease for only a brief period before drug resistance emerges. One mechanism of drug resistance involves the overexpression of type 5 17-β-hydroxysteroid dehydrogenase (aldo-keto reductase 1C3 or AKR1C3), a major enzyme responsible for the formation of intratumoral androgens that activate the androgen receptor (AR). 3-((4-Nitronaphthalen-1-yl)amino)benzoic acid 1 is a "first-in-class" AKR1C3 competitive inhibitor and AR antagonist. Compound 1 was compared in a battery of in vitro studies with structurally related N-naphthyl-aminobenzoates, and AKR1C3 targeted therapeutics e.g. GTx-560 and ASP9521, as well as with R-bicalutamide, enzalutamide and abiraterone acetate. Compound 1 was the only naphthyl derivative that was a selective AKR1C3 inhibitor and AR antagonist in direct competitive binding assays and in AR driven reporter gene assays. GTx-560 displayed weak activity as a direct AR antagonist but had high potency in the AR reporter gene assay consistent with its ability to inhibit the co-activator function of AKR1C3. By contrast ASP9521 did not act as either an AR antagonist or block AR reporter gene activity. Compound 1 was the only compound that showed comparable potency to inhibit AKR1C3 and act as a direct AR antagonist. Compound 1 blocked the formation of testosterone in LNCaP-AKR1C3 cells, and the expression of PSA driven by the AKR1C3 substrate (4-androstene-3,17-dione) and by an AR agonist, 5α-dihydrotestosterone consistent with its bifunctional role. Compound 1 blocked the nuclear translocation of the AR at similar concentrations to enzalutamide and caused disappearance of the AR from cell lysates. R-biaclutamide and enzalutamide inhibited AKR1C3 at concentrations 200x greater than compound 1, suggesting that its bifunctionality can be explained by a shared pharmacophore that can be optimized.

Induction of ferroptosis by singlet oxygen generated from naphthalene endoperoxide

Singlet oxygen causes a cytotoxic process in tumor cells in photodynamic therapy (PDT) and skin photoaging. The mechanism responsible for this cytotoxicity is, however, not fully understood. 1-Methylnaphthalene-4-propionate endoperoxide (MNPE) is a cell-permeable endoperoxide that generates pure singlet oxygen. We previously reported that cell death induced by MNPE did not show the typical profile of apoptosis, and the cause of this cell death remains elusive. We report herein on an investigation of the mechanism for MNPE-induced cell death from the view point of ferroptosis. The findings indicate that the MNPE treatment decreased the viabilities of mouse hepatoma Hepa 1-6 cells in vitro, and that this decrease was accompanied by increases in the concentrations of both intracellular ferrous iron and the level of lipid peroxidation, but that the caspase-mediated apoptotic pathway was not activated. The intracellular levels of cysteine and glutathione were not affected by the MNPE treatment. Importantly, an assay of lactate dehydrogenase activity revealed that the cell death caused by MNPE was suppressed by ferrostatin-1, a ferroptosis-specific inhibitor. Collectively, these results strongly indicate that ferroptosis is the main cell death pathway induced by singlet oxygen.

TERT inhibition leads to reduction of IL-6 expression induced by palmitic acid and interferes with the protective effects of tibolone in an astrocytic cell model

Although it has been shown that telomerase has neuroprotective effects, mainly as a result of its non-canonical functions in neuronal cells, its role with respect to glial cells remains unknown. There is growing evidence indicating that telomerase plays an important role with respect to inflammation, especially in the regulation of pro-inflammatory cytokine gene expression. The present study aimed to evaluate the role of telomerase in an astrocyte cell model treated with palmitic acid (PA) and tibolone. Cell death, reactive oxygen species production and interleukin-6 expression were evaluated under telomerase inhibition with the BIBR1532 compound in T98G cells treated with tibolone and PA, using fluorometry, flow cytometry, enzyme-linked immunosorbent assays and the quantitative polymerase chain reaction. The results obtained showed that telomerase protein was increased by PA after 36 hours, alone or in combination with tibolone, and that its activity was affected by PA. Telomerase inhibition reduced interleukin-6 expression and it interfered with the protective effects of tibolone on cell death. Moreover, tibolone increased Tyr707 phosphorylation in PA-treated cells. In the present study, we provide novel findings about the regulation of telomerase by PA and tibolone. Telomerase was involved in inflammation by PA and in protective effects of tibolone. Therefore, we conclude that telomerase could play a dual role in these cells.

Characterisation of the Ral GTPase inhibitor RBC8 in human and mouse platelets

The Ral GTPases, RalA and RalB, have been implicated in numerous cellular processes, but are most widely known for having regulatory roles in exocytosis. Recently, we demonstrated that deletion of both Ral genes in a platelet-specific mouse gene knockout caused a substantial defect in surface exposure of P-selectin, with only a relatively weak defect in platelet dense granule secretion that did not alter platelet functional responses such as aggregation or thrombus formation. We sought to investigate the function of Rals in human platelets using the recently described Ral inhibitor, RBC8. Initial studies in human platelets confirmed that RBC8 could effectively inhibit Ral GTPase activation, with an IC50 of 2.2 μM and 2.3 μM for RalA and RalB, respectively. Functional studies using RBC8 revealed significant, dose-dependent inhibition of platelet aggregation, secretion (α- and dense granule), integrin activation and thrombus formation, while α-granule release of platelet factor 4, Ca2+ signalling or phosphatidylserine exposure were unaltered. Subsequent studies in RalAB-null mouse platelets pretreated with RBC8 showed dose-dependent decreases in integrin activation and dense granule secretion, with significant inhibition of platelet aggregation and P-selectin exposure at 10 μM RBC8. This study strongly suggests therefore that although RBC8 is useful as a Ral inhibitor in platelets, it is likely also to have off-target effects in the same concentration range as for Ral inhibition. So, whilst clearly useful as a Ral inhibitor, interpretation of data needs to take this into account when assessing roles for Rals using RBC8.

Comprehensive chemical profiling of monascus-fermented rice product and screening of lipid-lowering compounds other than monacolins

ETHNOPHARMACOLOGICAL RELEVANCE

Monascus-fermented rice product (MFRP) has been regarded as a dietary supplement and traditional medicine with circulation-promoting effects in China and other countries for centuries.

AIM OF THE STUDY

This study was carried out to profile the chemical components in MFRP, and provide available information for elucidating the potential lipid-lowering compounds other than monacolins.

MATERIALS AND METHODS

High-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF MS) and gas chromatography coupled with mass spectrometry (GC-MS) methods were applied to comprehensive analysis of chemical components in MFRP. Potential small molecules were identified by comparing with reference standards, or tentatively characterized by comparing their retention time and high-resolution mass spectral data with previous literature. The lipid-lowering properties of ten major non-monacolin compounds were evaluated in cholesterol-fed zebrafish larvae. And one with optimum lipid-lowering activity was subsequently evaluated in high fat diet-fed C57BL/6 J mice, with the dyslipidemia and ectopic lipid deposition being investigated.

RESULTS

A total of 99 compounds were characterized in MFRP, including 38 monacolins, 5 decalins, 6 isoflavones, 13 pigments, 8 azaphilonoids, 11 amino acids, 4 nucleosides, 9 lipid acids, 4 phytosterols and glycerol. The preliminary screening showed that ergosterol remarkably reduced cholesterol levels in zebrafish larvae. Moreover, ergosterol delayed body weight gain and decreased circulating total cholesterol, triglyceride, low density lipoprotein cholesterol levels in high fat diet-fed mice. Ectopic lipid accumulation was also ameliorated in the liver and heart of obese mice.

CONCLUSION

Global analysis of chemical components and screening of lipid-lowering non-monacolin compounds in MFRP have improved our understanding of its therapeutic material basis.