ATP Concentration Research Articles

Abstract 4820: The disassembly of amyloid-bodies

Abstract The ability of cells to adapt to a wide variety of stress conditions plays a critical role in various physiological and pathological settings, including development, cancer and neurological disorders. We recently reported the discovery of stress-induced low complexity noncoding RNA derived from stimuli-specific loci of the ribosomal intergenic spacer (rIGSRNA); an enigmatic region of the human genome historically dismissed as “junk” DNA. We showed that low complexity rIGSRNA activate a physiological amyloidogenic program that converts the nucleolus into Amyloid-bodies: a molecular prison of immobilized proteins in an amyloid-like state. This conserved post-translational regulatory pathway enables cells to rapidly and reversibly store an array of endogenous proteins in Amyloid-bodies and enter a dormant-like phenotype in response to severe environmental insults. While many membrane-less compartments have been described as liquid-like (e.g., stress granules, P-bodies, germ cell granules), our discovery of Amyloid-bodies provided evidence of an amyloidogenic process that can physiologically transition biological matter to a solid-like state. The ability of mammalian cells to efficiently dissemble Amyloid-bodies raises a fundamental question: Are mammalian cell disaggregases involved in Amyloid-body disassembly? Here, we show that Amyloid-bodies undergo a solid-to-liquid-phase transition to release sequestered proteins and restore nucleolar functions. An RNAi screened identified key Heat Shock Proteins (Hsps) that remodel Amyloid-bodies back to the liquid nucleoli on stress termination. The composition of mammalian disaggregases differs considerably from non-metazoans and those involved in disassembly of pathological amyloids in vitro. Activation of mammalian disaggregases and Amyloid-body disassembly is dependent on ATP concentration. Conceptually, this work identifies metazoan disaggregases challenging the widely accepted paradigm that the amyloid state is irreversible in mammalian cells. The data also provides alternative insights into pathogenic amyloids by examining their disassembly in cellular systems. Citation Format: Chloe Kirk, Michael Bokros, Alex Grunfeld, Stephen Lee. The disassembly of amyloid-bodies. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4820.

Abstract 397: The role of heparan sulfate in enhancing the chemotherapeutic response in triple-negative breast cancer

Abstract Among women worldwide, breast cancer has the highest incidence and is the leading cause of cancer-related death. Patients with the triple-negative breast cancer (TNBC) subtype have an inferior prognosis in comparison to other breast cancers because the current therapies do not facilitate long-lasting responses. Thus, there is a critical need for novel therapeutic strategies that induce stronger responses. In our previous research, we discovered that augmenting the concentration of extracellular ATP (eATP) greatly enhances the chemotherapeutic response of TNBC cell lines by activating purinergic receptors (P2RXs), leading to cell death through the induction of non-selective membrane permeability. However, eATP levels are limited by several classes of extracellular ATPases. One endogenous molecule of interest that can inhibit multiple classes of extracellular ATPases is heparan sulfate. Heparan sulfate itself is degraded by heparanase, an enzyme that is known to be highly expressed in various cancers, including breast cancer. Heparan sulfate has previously been shown to regulate several cancer-related processes such as fibroblast growth factor signaling, neoangiogenesis by sequestering vascular endothelial growth factors in the extracellular matrix, hedgehog signaling and cell adhesion. In this project, we identified an additional mechanism for a tumor suppressor role of heparan sulfate: inhibition of extracellular ATPases, leading to augmented levels of eATP. Several heparanase inhibitors have been previously identified, including OGT 2115, suramin, PI-88, and PG 545. We hypothesized that heparanase inhibitors would augment eATP concentrations in TNBC by increasing heparan sulfate in the tumor microenvironment, resulting in increased cell death in response to chemotherapy. We treated TNBC cell lines MDA-MB 231, Hs 578t, and MDA-MB 468 and non-tumorigenic immortal mammary epithelial MCF-10A cells with increasing concentrations of the chemotherapeutic agent paclitaxel in the presence of heparan sulfate and/or OGT 2115 with eATP content and cell viability being assessed. Moreover, to confirm that the effects of OGT 2115 are mediated through eATP, we utilized specific antagonists to the purinergic receptors P2RX4 and P2RX7. In addition, the protein expression of heparanase was compared in all the examined cell lines via Western blot analysis. We also evaluated the effects of this combination on the breast cancer-initiating cell population in the treated cells using flow cytometry and tumorsphere formation efficiency assays. These results demonstrate that inhibiting the degradation of heparan sulfate in the tumor microenvironment enhances the susceptibility of TNBC cell lines to chemotherapy by augmenting extracellular ATP concentrations. This strategy could potentially be used to induce deeper and more durable responses in triple-negative breast cancer patients. Citation Format: Jasmine M. Manouchehri, Jharna Datta, Mathew A. Cherian. The role of heparan sulfate in enhancing the chemotherapeutic response in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 397.

Abstract 4008: TAS2940, a novel brain-penetrable pan-ERBB inhibitor, exhibits tumor regression and prolongs survival in intracranial models bearing ERBB aberrations

Abstract Background: Primary and metastatic brain tumors have significant unmet medical needs as few drugs can penetrate the blood-brain barrier (BBB). Brain metastasis is more common in non-small cell lung cancer (NSCLC) and breast cancer than in other cancers. Genetic alterations in ERBB family genes are frequently observed in those cancers, with about half of HER2/EGFR aberrations metastasizing in the brain. EGFR aberrations have been also observed in glioblastoma. Several pan-ERBB inhibitors are clinically available or under clinical development, such as afatinib, neratinib, and poziotinib. However, none are highly brain-penetrable as they are pumped out via the BBB. Here, we report TAS2940 as a novel potent pan-ERBB inhibitor that elicits brain penetrability and anti-tumor effects in brain metastasis models. Methods: The kinase selectivity of TAS2940 was evaluated in a panel of 257 kinases. Autophosphorylation of wild-type and mutant ERBB in stably expressing cell lines was evaluated using a quantitative immunofluorescence assay. The growth inhibitory effect on cell lines expressing HER2/EGFR aberrations was evaluated based on quantitation of the cellular ATP concentration. Cell lines were transplanted subcutaneously or intracranially in BALB/cAJcl-nu/nu mice. HER2 tyrosine kinase inhibitors, including TAS2940, were then orally administered once daily followed by evaluation of tumor volume and body weight. Results: TAS2940 showed potent and selective inhibition against ERBB family proteins over more than 250 kinases on enzymatic assay. TAS2940 also showed preferential cytotoxicity in cells harboring HER2/EGFR genetic alterations in vitro, while sparing cells without ERBB genetic aberrations. TAS2940 showed potent anti-proliferative activity in cells containing HER2 genetic alterations or EGFR exon 20 insertions, commonly found in NSCLC or breast cancer, as well as EGFRvIII alterations, frequently observed in glioblastoma. In vivo xenograft tumor models with various EGFR genetic alterations showed that TAS2940 exerted anti-tumor effects, such as growth retardation or regression. We further examined brain penetration by assessing the brain to blood concentration of TAS2940 in mice with intact BBBs, showing higher brain penetrability compared to other ERBB inhibitors. Evaluation of TAS2940 in intracranial brain metastasis mouse models resulted in tumor regression and prolonged survival. Conclusion: TAS2940 is a novel potent and selective pan-ERBB inhibitor with high brain penetrability in vivo. These results support the clinical development of TAS2940 in primary and metastatic brain tumors driven by ERBB genetic aberrations. Citation Format: Kei Oguchi, Hikari Araki, Shingo Tsuji, Masayuki Nakamura, Akihiro Miura, Kaoru Funabashi, Akiko Osada, Sakiho Tanaka, Takamasa Suzuki, Shinji Mizuarai. TAS2940, a novel brain-penetrable pan-ERBB inhibitor, exhibits tumor regression and prolongs survival in intracranial models bearing ERBB aberrations. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4008.

Abstract 3391: Dual inhibition of RAS and the IGF2/IGF1R pathways: a potential targeting strategy for RAS-mutated embryonal rhabdomyosarcoma

Abstract Background: Mutations in RAS is reported in embryonal rhabdomyosarcoma (ERMS). Upregulation of IGF2/IGF1R axis and IGF2 overexpression is a common finding. Targeting RAS downstream is associated with high toxicity. Combination therapies targeting parallel pathways is necessary to overcome treatment resistance. Dual inhibition of RAS downstream and IGF2/IGF1R axis can be a potential mechanism of targeted treatment. The efficacy of this mechanism was studied using a microcancer 3D exvivo tumor cell viability assay in a KRAS mutant ERMS. Design: Tumor was collected for a high-risk pediatric ERMS patient. Comprehensive genomic analysis, for identification of targetable genomic alterations, was performed by integrating WES, MPseq and RNAseq. Tumor spheroids grown in 3D environment were tested against multiple single drugs and combinations. The tumor viability was assed employing the Cell Titer Glow Luminescent Cell Viability Assay. Results were expressed as nMATP and were shown as drug-response curve exhibiting the ATP concentration changes at Cmax. Results: Genomic findings included an oncogenic KRAS (G12D) mutation. BAY-293 has a partial cell killing response as a single agent. Given to the presence of IGF2 over-expression, IGF2/IGF1R pathway was targeted by linsitinib. Addition of BAY-293 to linsitinib led to enhanced effectiveness of this agent (Table 1). Conclusion: Combination of comprehensive genomic profiling and a laboratory-based 3D micro-cancer model using the patient’s own tumor is an effective way to determine drug efficacy. Targeting RAS pathway by single agents, increases the possibility of resistance. Dual targeting of downstream pathways by MEK and PI3K pathway inhibition is highly toxic, and the clinical usage of this combination is limited. Our results have indicated inhibition of IGF-1R/IGF2 axis in combination with other agents targeting RAS pathway, can be a potential method to address these limitations. ABEL 1. Summary of molecular alterations and targeting methods Molecular alteration Drug Target Kill% at Cmax KRAS (G12D) Mutation BAY-293 RAS-SOS1 interaction 55.3 Trametinib MEK1/2 88.3 Selumetinib MEK1/2 76 Paxalisib PI3K/mTOR 89.7 Samotolisib PI3K/mTOR 92.9 Copanlisib PI3K 95.2 Perifosine AKT 89.2 IGF2 Over-expression Linsitinib IGF-1R/InsR 84.1 BMS-754807 IGF-1R/InsR 67.4 NTRK2 mutation Larotrectinib NTRK 41.9 KMT2D mutation Panobinostat HDAC 85.3 Combinations Kill% at Cmax BAY-293+Selumetinib 100 BAY-293+Samotolisib 100 BAY-293+Paxalisib 99.7 BAY-293+Linsitinib 97.5 Selumetinib+Samotolisib 93.1 Citation Format: Dorsay Sadeghian, Wan-Hsin Lin, James Smadbeck, Alan Panheiter, Michael Barrett, Alexa F. Mccune, Giannoula Karagouga, Sarah Johnson, Ryan W. Feathers, Faye R. Harris, Lindsey Kinsella, Taylor Berry, John Cheville, Panos Anastasiadis, Candace Granberg, Patricio Gargollo, Vasmatzis George. Dual inhibition of RAS and the IGF2/IGF1R pathways: a potential targeting strategy for RAS-mutated embryonal rhabdomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3391.

The relationship between microbial community vitality and ATP bioburden in bottom waters under fuel microcosms.

Adenylate energy charge (AEC) - computed from the ATP, ADP and AMP concentrations in a specimen - reflect the net physiological state of the microbial population in that specimen. Previous research has demonstrated that healthy microbial populations maintain AEC≥0.8. As populations are subjected to stresses, or - in closed systems - deplete the available nutrients, respond to the accumulation of toxic metabolites, or both, AEC decreases (often to <0.5). Aqueous-phase samples from a set of fuel-water microcosms were tested for cellular ATP (cATP) and AEC. This paper reports on the precision of the AEC test method and the relationship between cellular AEC and cATP bioburdens in the aqueous phase of fuel over aqueous-phase microcosms.

Dissipation and energy propagation across scales in an active cytoskeletal material

Living systems are intrinsically nonequilibrium: They use metabolically derived chemical energy to power their emergent dynamics and self-organization. A crucial driver of these dynamics is the cellular cytoskeleton, a defining example of an active material where the energy injected by molecular motors cascades across length scales, allowing the material to break the constraints of thermodynamic equilibrium and display emergent nonequilibrium dynamics only possible due to the constant influx of energy. Notwithstanding recent experimental advances in the use of local probes to quantify entropy production and the breaking of detailed balance, little is known about the energetics of active materials or how energy propagates from the molecular to emergent length scales. Here, we use a recently developed picowatt calorimeter to experimentally measure the energetics of an active microtubule gel that displays emergent large-scale flows. We find that only approximately one-billionth of the system's total energy consumption contributes to these emergent flows. We develop a chemical kinetics model that quantitatively captures how the system's total thermal dissipation varies with ATP and microtubule concentrations but that breaks down at high motor concentration, signaling an interference between motors. Finally, we estimate how energy losses accumulate across scales. Taken together, these results highlight energetic efficiency as a key consideration for the engineering of active materials and are a powerful step toward developing a nonequilibrium thermodynamics of living systems.

2‐Phenylquinazolin‐4(3H)‐one scaffold as newly designed, synthesized VEGFR‐2 allosteric inhibitors with potent cytotoxicity through apoptosis

New derivatives of 2-phenylquinazolin-4(3H)-one were designed, synthesized, and biologically evaluated as potent allosteric kinase inhibitors with in situ cytotoxicity against MCF-7 and HepG2 cells. Compounds 15 and 18 among the proposed compounds showed promising antiproliferative activity against MCF-7 (IC50 = 1.35 µM) and HepG2 cells (IC50 = 3.24 µM), comparable to sorafenib, with IC50 values of 3.04, 2.93 µM, respectively, according to in situ cytotoxicity testing. Comparing compounds 15 and 18 to sorafenib, the in vitro VEGFR-2 inhibitory activity displayed encouraging selective efficacy with IC50 values of 13, 67, and 30 nM, respectively. Results of VEGFR-2 inhibition at various ATP concentrations proved that there was no statistically significant difference between the IC50 values, which improved the non-ATP competitive binding. Compound 15 caused apoptotic breast cancer cell death with 55.11-fold cell-cycle arrest at the S-phase, where it affected the apoptosis-mediated genes through upregulating P53, Bax, caspases 3, 8, and 9 and downregulating the antiapoptotic gene Bcl-2. A molecular docking study was conducted to confirm the binding of the designed compounds to the allosteric site of VEGFR-2 in DFG-out mode, leaving the ATP-binding pocket unoccupied when superimposed to the pose of sorafenib. The designed molecules showed resealable binding affinity toward the DFG loop and the allosteric site. Hence, the 2-phenylquinazolin-4(3H)-one derivative constitutes intriguing starting points for designing apoptotic-inducing drugs.

ATP modulates self-perpetuating conformational conversion generating structurally distinct yeast prion amyloids that limit autocatalytic amplification

Prion-like self-perpetuating conformational conversion of proteins into amyloid aggregates is associated with both transmissible neurodegenerative diseases and non-Mendelian inheritance. The cellular energy currency ATP is known to indirectly regulate the formation, dissolution, or transmission of amyloid-like aggregates by providing energy to the molecular chaperones that maintain protein homeostasis. In this work, we demonstrate that ATP molecules, independent of any chaperones, modulate the formation and dissolution of amyloids from a yeast prion domain (NM domain of Saccharomyces cerevisiae Sup35) and restricts autocatalytic amplification by controlling the amount of fragmentable and seeding-competent aggregates. ATP, at (high) physiological concentrations in the presence of Mg2+, kinetically accelerates NM aggregation. Interestingly, ATP also promotes phase-separation-mediated aggregation of a human protein harboring a yeast prion-like domain. We also show that ATP disaggregates preformed NM fibrils in a dose-independent manner. Our results indicate that ATP-mediated disaggregation, unlike the disaggregation by the disaggregase Hsp104, yields no oligomers that are considered one of the critical species for amyloid transmission. Furthermore, high concentrations of ATP delimited the number of seeds by giving rise to compact, ATP-bound NM fibrils that exhibited nominal fragmentation by either free ATP or Hsp104 disaggregase to generate lower molecular weight amyloids. Additionally, (low) pathologically relevant ATP concentrations restricted autocatalytic amplification by forming structurally distinct amyloids which are found seeding-inefficient due to their reduced β-content. Our results provide key mechanistic underpinnings of concentration-dependent chemical chaperoning by ATP against prion-like transmissions of amyloids.

Pushing Adenosine and ATP SELEX for DNA Aptamers with Nanomolar Affinity.

The classical DNA aptamer for adenosine and ATP has been the most used small molecule binding aptamer for biosensing, imaging, and DNA nanotechnology. This sequence has recurred multiple times in previous aptamer selections, and all previous selections used a high concentration of ATP as the target. Herein, two separate selections were performed using adenosine and ATP as targets. By pushing the target concentrations down to the low micromolar range, two new aptamers with Kd as low as 230 nM were obtained, showing around 30-fold higher affinity compared to the classical aptamer. The classical aptamer sequence still dominated the library in the early rounds of the selections, but it was suppressed in the later rounds. The new aptamers bind to one target molecule instead of two. Mutation studies confirmed their secondary structures and specific binding. Using the deep sequencing data from the selections, long-standing questions such as the existence of one-site aptamers and mutation distribution in the classical aptamer were addressed. Comparisons were made with previously reported DNA aptamers for ATP. Finally, a strand-displacement biosensor was tested showing selectivity for adenosine and its nucleotides.

Ratiometric fluorescence biosensing of silver NanoCluster Beacons for ATP detection based on ligation- triggered rolling cycle amplification

NanoCluster Beacon (NCB) provided a label-free ratiometric fluorescence method with obvious dual-color signal output. In this work, a novel method was developed for ATP detection by coupling NCB and rolling cycle amplification (RCA). NCB was composed of the silver clusters (P2-AgNCs) and the converter (P3), and the linker sequence (P1) kept them in close proximity by Watson-Crick base pairing. The fluorescence performance of NCB was correlated with the status of the AgNCs. Controllable color switching from green to red was thus achieved. ATP served as cofactor of T4 DNA ligase to catalyze the ligation reaction, then the subsequent RCA reaction produced a long-stranded linear DNA with a lot of P1 sequences that assembled with NCBs. So that the green fluorescence of AgNCs (λem = 542 nm) was transformed to bright red fluorescence (λem = 630 nm), lighting up the ratiometric fluorescence of NCBs. Under the optimized conditions, the value of F630 nm/F542 nm (F630/542) was linearly correlated with the logarithmic ATP concentration with a detection limit of 122 pM. Furthermore, the proposed method showed good performance in human serums, indicating its potential to be applied in clinical diagnosis.

Recombinant Analogs of Sea Anemone Kunitz-Type Peptides Influence P2X7 Receptor Activity in Neuro-2a Cells

Purinergic P2X7 receptors (P2X7) have now been proven to play an important role and represent an important therapeutic target in many pathological conditions including neurodegeneration. Here, we investigated the impact of peptides on purinergic signaling in Neuro-2a cells through the P2X7 subtype in in vitro models. We have found that a number of recombinant peptides, analogs of sea anemone Kunitz-type peptides, are able to influence the action of high concentrations of ATP and thereby reduce the toxic effects of ATP. The influx of calcium, as well as the fluorescent dye YO-PRO-1, was significantly suppressed by the studied peptides. Immunofluorescence experiments confirmed that the peptides reduce the P2X7 expression level in neuronal Neuro-2a cells. Two selected active peptides, HCRG1 and HCGS1.10, were found to specifically interact with the extracellular domain of P2X7 and formed stable complexes with the receptor in surface plasmon resonance experiments. The molecular docking approach allowed us to establish the putative binding sites of the most active HCRG1 peptide on the extracellular domain of the P2X7 homotrimer and propose a mechanism for regulating its function. Thus, our work demonstrates the ability of the Kunitz-type peptides to prevent neuronal death by affecting signaling through the P2X7 receptor.

Effect of preliminary stresses on the induction of viable but non-culturable Escherichia coli O157:H7 NCTC 12900 and Staphylococcus aureus ATCC 6538

As a novel non-thermal pasteurization technology, high pressure carbon dioxide (HPCD) has been used in food processing. However, it could induce microorganisms into a viable but nonculturable (VBNC) state, posing a potential risk to food safety and public health. In this study, we attempted to investigate the effect of various preliminary stresses including cold, heat, osmosis, acidity and oxidation on HPCD-induced VBNC formation. The results indicated that there was no effect of preliminary stresses on VBNC Staphylococcus aureus induction. However, heat, acidity and long-term (24 h) cultivation preadaptation could significantly increase the VBNC E. coli production induced by HPCD. Transcriptome analysis revealed that genes involved in ATP production were significantly decreased in these three stress-treated cells, and further ATP levels determination revealed that the ATP levels of the cell were significantly decreased after heat, acidity and long-term cultivation preadaptation, implying the decrease of ATP level caused by these stresses might be the reason for increasing VBNC production. To further study the relationship between ATP level and VBNC cell ratios after preadaptation. We artificially decreased the ATP levels, and detect their VBNC ratios after HPCD treatment. We found that with the ATP concentration decreasing after exposure to carbonyl cyanide m-chlorophenyl hydrazine (CCCP), the VBNC ratios were increased after HPCD treatment, indicating that the ATP contents were highly negatively correlated with VBNC ratios. This study proved that the preadaptation of heat, acidity and long-term cultivation could promote VBNC induction by decreasing the intracellular ATP level. In general, the obtained result gave the instruction about the storage environment for food materials, helped to further develop and optimize the HPCD processing to prevent VBNC formation and accelerate the development of HPCD technology in food industry.

Prognostic factors in the treatment of androgenetic alopecia with minoxidil

Introduction. Androgenetic alopecia (AGA) is the most common type of alopecia, characterized by diffuse progressive thinning of the hair in the fronto-parietal area in patients with a genetic predisposition. Topical minoxidil remains the primary pharmacological treatment for AGA both in men and women. The efficacy in hair regrowth is reported to be between 40 and 50%.Aim. To evaluate prognostic factors of minoxidil response in AGA patients.Matherials and methods. The prospective open study was carried out. Thirty participants with AGA were enrolled and completed the study (twenty one women I–II Ludwig stage and nine men I–III Hamilton – Norwood stage). Primary outcomes consisted of measuring of hair density, telogen hair rate, the percentage of vellus hairs and hair diameter at baseline and repeated at 4 months. The SULT1A1 enzyme activity and the concentration of ATP in plucked hairs were measured at baseline. Patients were treated with 5% topical minoxidil applying daily for 4 months. In order to investigate prognostic factors in groups of responders and non-responders to minoxidil treatment these measured morphometric and biochemical characteristics were assessed.Results. After 4 months of treatment 77% of patients demonstrated hair regrowth and improvement of hair density, hair diameter and decrease of vellus hairs level. The SULT1A1 enzyme activity (p = 0.0008), the concentration of ATP (p = 0.004) in plucked hairs and baseline total hair density (p = 0.01) was significantly lower in group of non-responders compared to group of responders. The study demonstrated strong positive correlation between SULT1A1 enzyme activity and increase of total hair density (r = 0.7, р = 0.00002); moderate positive correlation was founded between concentration of ATP and increase of total hair density (r = 0.6, р = 0.0004).Conclusion. The negative prognostic factors for minoxidil treatment of AGA include SULT1A1 enzyme activity, concentration of ATP in plucked hairs and low total hair density at baseline.

Antifungal evaluation of quinoline-chalcone derivatives combined with FLC against drug-resistant Candida albicans

With the widespread clinical use of FLC, the FLC-resistant C. albicans greatly increases the difficulty of treatment, and drug combination becomes an important method to treat C. albicans infection. In this work, we have prepared a series of quinoline-chalcone derivatives in good yields, and in vitro antifungal activity against C. albicans were evaluated. The results indicated that most title compounds combined with FLC showed good antifungal activity against drug-resistant C. albicans. Further mechanism researches demonstrated that 6a and 6c combined with FLC could significantly inhibited growth and biofilm formation of C. albicans, induce ROS accumulation, impair the mitochondrial membrane, and decrease intracellular ATP concentrations.

MFN2 deficiency affects calcium homeostasis in lung adenocarcinoma cells via downregulation of UCP4.

Mitofusin-2 (MFN2) is a transmembrane GTPase that regulates mitochondrial fusion and thereby modulates mitochondrial function. However, the role of MFN2 in lung adenocarcinoma remains controversial. Here, we investigated the effect of MFN2 regulation on mitochondria in lung adenocarcinoma. We found that MFN2 deficiency resulted in decreased UCP4 expression and mitochondrial dysfunction in A549 and H1975 cells. UCP4 overexpression restored ATP and intracellular calcium concentration, but not mtDNA copy number, mitochondrial membrane potential or reactive oxygen species level. Furthermore, mass spectrometry analysis identified 460 overlapping proteins after independent overexpression of MFN2 and UCP4; these proteins were significantly enriched in the cytoskeleton, energy production, and calponin homology (CH) domains. Moreover, the calcium signaling pathway was confirmed to be enriched in KEGG pathway analysis. We also found by protein-protein interaction network analysis that PINK1 may be a key regulator of MFN2- and UCP4-mediated calcium homeostasis. Furthermore, PINK1 increased MFN2/UCP4-mediated intracellular Ca2+ concentration in A549 and H1975 cells. Finally, we demonstrated that low expression levels of MFN2 and UCP4 in lung adenocarcinoma are associated with poor clinical prognosis. In conclusion, our data suggest not only a potential role of MFN2 and UCP4 in co-regulating calcium homeostasis in lung adenocarcinoma but also their potential use as therapeutic targets in lung cancer.

Synthesis and structure–activity relationships of ticlopidine derivatives and analogs as inhibitors of ectonucleotidase CD39

Ticlopidine is an antithrombotic prodrug of the thienotetrahydropyridine family. For platelet inhibition it has to undergo oxidative ring-opening by cytochrome P450 enzymes. The resulting thiol reacts with a cysteine residue of the purinergic P2Y12 receptor on thrombocytes resulting in covalent receptor blockade. Ticlopidine in its intact, not-metabolized form was previously shown to inhibit ecto-nucleoside triphosphate diphosphohydrolase-1 (NTPDase1, also known as cluster of differentiation (CD) 39). CD39 catalyzes the extracellular hydrolysis of ATP via ADP to AMP, which is further hydrolyzed by ecto-5′-nucleotidase (CD73) to adenosine. CD39 inhibition has been proposed as a novel strategy to increase the extracellular concentration of antiproliferative ATP, while decreasing immunosuppressive and cancer-promoting adenosine levels. In the present study, we performed an extensive structure–activity relationship (SAR) analysis of ticlopidine derivatives and analogs as CD39 inhibitors followed by an in-depth characterization of selected compounds. Altogether 74 compounds were synthesized, 41 of which are new, not previously described in literature. Benzotetrahydropyridines, in which the metabolically labile thiophene is replaced by a benzene ring, were discovered as a new class of allosteric CD39 inhibitors.

Survival of Escherichia coli after high-antibiotic stress is dependent on both the pregrown physiological state and incubation conditions.

The survival of bacterial cells exposed to antibiotics depends on the mode of action, the antibiotics concentration, and the duration of treatment. However, it also depends on the physiological state of the cells and the environmental conditions. In addition, bacterial cultures contain sub-populations that can survive high antibiotic concentrations, so-called persisters. Research on persisters is challenging due to multiple mechanisms for their formation and low fractions, down to and below one millionth of the total cell population. Here, we present an improved version of the persister assay used to enumerate the amount of persisters in a cell population. The persister assay with high antibiotic stress exposure was performed at both growth supporting and non-supporting conditions. Escherichia coli cells were pregrown to various growth stages in shake flasks and bench-top bioreactors. In addition, the physiological state of E. coli before antibiotic treatment was determined by quantitative mass spectrometry-based metabolite profiling. Survival of E. coli strongly depended on whether the persister assay medium supported growth or not. The results were also highly dependent on the type of antibiotic and pregrown physiological state of the cells. Therefore, applying the same conditions is critical for consistent and comparable results. No direct connection was observed between antibiotic efficacy to the metabolic state. This also includes the energetic state (i.e., the intracellular concentration of ATP and the adenylate energy charge), which has earlier been hypothesized to be decisive for persister formation. The study provides guides and suggestions for the design of future experimentation in the research fields of persisters and antibiotic tolerance.

A rapid method for measuring ATP + ADP + AMP in marine sediment.

In this report, I describe a method for rapid measurement of total adenylate (ATP + ADP + AMP) in marine sediment samples for estimating microbial biomass. A simple 'boil and dilute' method is described here, whereby adding boiled MilliQ water to sediments increases the detection limit for ATP + ADP + AMP up to 100-fold. The lowered detection limit of this method enabled the detection ATP + ADP + AMP in relatively low-biomass sub-seafloor sediment cores with 104 16S rRNA gene copies per gram. Concentrations of ATP + ADP + AMP correlated with 16S rRNA gene concentrations from bacteria and archaea across six different sites that range in water depth from 1 to 6000 m indicating that the ATP + ADP + AMP method can be used as an additional biomass proxy. In deep sea microbial communities, the ratio of ATP + ADP + AMP concentrations to 16S rRNA genes >1m below seafloor was significantly lower compared to communities in the upper 30 cm of sediment, which may be due to reduced cell sizes and or lower ATP + ADP + AMP concentrations per cell in the deep sea sub-seafloor biosphere. The boil and dilute method for ATP + ADP + AMP is demonstrated here to have a detection limit sufficient for measuring low biomass communities from deep sea sub-seafloor cores. The method can be applied to frozen samples, enabling measurements of ATP + ADP + AMP from frozen sediment cores stored in core repositories from past and future international drilling campaigns.

Assessing the Benefits and Costs of the Hydrogen Cyanide Antiherbivore Defense in Trifolium repens.

Understanding the evolution of plant defenses against herbivores requires identifying the benefits and costs of defense. Here, we tested the hypothesis that the benefits and costs of hydrogen cyanide (HCN) defense against herbivory on white clover (Trifolium repens) are temperature dependent. We first tested how temperature affected HCN production in vitro, and then examined how temperature influenced the efficacy of HCN defense of T. repens against a generalist slug (Deroceras reticulatum) herbivore using no-choice and choice feeding trial assays. To understand how temperature affected the costs of defense, plants were exposed to freezing, and HCN production, photosynthetic activity, and ATP concentration were quantified. HCN production increased linearly from 5 °C to 50 °C, and cyanogenic plants experienced reduced herbivory compared to acyanogenic plants only at warmer temperatures when fed upon by young slugs. Freezing temperatures induced cyanogenesis in T. repens and decreased chlorophyll fluorescence. Cyanogenic plants experienced lower ATP levels than acyanogenic plants due to freezing. Our study provides evidence that the benefits of HCN defense against herbivores are temperature dependent, and freezing may inhibit ATP production in cyanogenic plants, but the physiological performance of all plants recovered quickly following short-term freezing. These results contribute to understanding how varying environments alter the benefits and costs of defense in a model system for the study of plant chemical defenses against herbivores.

ATP and its metabolite adenosine cooperatively upregulate the antigen-presenting molecules on dendritic cells leading to IFN-γ production by T cells

Dendritic cells (DCs) present foreign antigens to T cells via the major histocompatibility complex (MHC), thereby inducing acquired immune responses. ATP accumulates at sites of inflammation or in tumor tissues, which triggers local inflammatory responses. However, it remains to be clarified how ATP modulates the functions of DCs. In this study, we investigated the effects of extracellular ATP on mouse bone marrow-derived dendritic cells (BMDCs) as well as the potential for subsequent T cell activation. We found that high concentrations of ATP (1mM) upregulated the cell surface expression levels of MHC-I, MHC-II, and co-stimulatory molecules CD80 and CD86 but not those of co-inhibitory molecules PD-L1 and PD-L2 in BMDCs. Increased surface expression of MHC-I, MHC-II, CD80, and CD86 was inhibited by a pan-P2 receptor antagonist. In addition, the upregulation of MHC-I and MHC-II expression was inhibited by an adenosine P1 receptor antagonist and by inhibitors of CD39 and CD73, which metabolize ATP to adenosine. These results suggest that adenosine is required for the ATP-induced upregulation of MHC-I and MHC-II. In the mixed leukocyte reaction assay, ATP-stimulated BMDCs activated CD4 and CD8T cells and induced interferon-γ (IFN-γ) production by these T cells. Collectively, these results suggest that high concentrations of extracellular ATP upregulate the expression of antigen-presenting and co-stimulatory molecules but not that of co-inhibitory molecules in BMDCs. Cooperative stimulation of ATP and its metabolite adenosine was required for the upregulation of MHC-I and MHC-II. These ATP-stimulated BMDCs induced the activation of IFN-γ-producing T cells upon antigen presentation.