31 research outputs found
Benzylserine inhibits breast cancer cell growth by disrupting intracellular amino acid homeostasis and triggering amino acid response pathways
No full textAbstract Background Cancer cells require increased levels of nutrients such as amino acids to sustain their rapid growth. In particular, leucine and glutamine have been shown to be important for growth and proliferation of some breast cancers, and therefore targeting the primary cell-surface transporters that mediate their uptake, L-type amino acid transporter 1 (LAT1) and alanine, serine, cysteine-preferring transporter 2 (ASCT2), is a potential therapeutic strategy. Methods The ASCT2 inhibitor, benzylserine (BenSer), is also able to block LAT1 activity, thus inhibiting both leucine and glutamine uptake. We therefore aimed to investigate the effects of BenSer in breast cancer cell lines to determine whether combined LAT1 and ASCT2 inhibition could inhibit cell growth and proliferation. Results BenSer treatment significantly inhibited both leucine and glutamine uptake in MCF-7, HCC1806 and MDA-MB-231 breast cancer cells, causing decreased cell viability and cell cycle progression. These effects were not primarily leucine-mediated, as BenSer was more cytostatic than the LAT family inhibitor, BCH. Oocyte uptake assays with ectopically expressed amino acid transporters identified four additional targets of BenSer, and gas chromatography-mass spectrometry (GCMS) analysis of intracellular amino acid concentrations revealed that this BenSer-mediated inhibition of amino acid uptake was sufficient to disrupt multiple pathways of amino acid metabolism, causing reduced lactate production and activation of an amino acid response (AAR) through activating transcription factor 4 (ATF4). Conclusions Together these data showed that BenSer blockade inhibited breast cancer cell growth and viability through disruption of intracellular amino acid homeostasis and inhibition of downstream metabolic and growth pathways
Neuartige Vanadium(IV)-phosphate für die Partialoxidation von kurzkettigen Kohlenwasserstoffen – Synthesen, Kristallstrukturen, Redox-Verhalten und katalytische Eigenschaften
No full textIn der vorliegenden Arbeit werden die Synthesen und Strukturen neuer, gemischter Übergangsmetall-vanadium(IV)-oxidphosphate beschrieben. Die erhaltenen Verbindungen sind katalytisch aktive Materialien für die Partialoxidation von Kohlenwasserstoffen. Die neuen Verbindungen, konnten durch Festkörperreaktion sowie durch thermischen Abbau geeigneter Vorläuferverbindungen erhalten werden. Das Tempern nahe am Schmelzpunkt von Gemengen aus Metall(III)- sowie Metall(II)-oxiden zusammen mit (VO)2P2O7 lieferte brauchbare Kristalle welche für eine Einkristallstrukturbestimmung herangezogen wurden. Es konnte die Kristallstruktur von V4O3(PO4)3 aus Einkristalluntersuchungen aufgeklärt werden (F2dd, Z = 24, a = 7,2596(8) Å, b = 21,786(2) Å, c = 38,904(4) Å, R(F) = 0,044, R(F2) = 0,066). Die partielle Substitution von Vanadium in MV3O3(PO4)3 durch Übergangsmetalle M (M = Cr, Fe, Ti) ist möglich. Die Struktur von CrV3O3(PO4)3 (F2dd, a = 7,246(1) Å, b = 21,740(3) Å, c = 38,785(6) Å) ist isotyp zu jener der reinen Vanadiumverbindung. Der Einbau von Eisen(III) führt zu der bisher nur als mikrokristallines Pulver erhältlichen Verbindung FeV3O3(PO4)3 die ein ähnliches Röntgenpulverbeugungsbild aufweist wie V4O3(PO4)3. Dieser Befund gibt einen weiteren Hinweis auf die kristallchemisch sehr interessante Variabilität der Lipscombit/Lazulit-Struktur. Als Produkte der Reaktion von Vanadyldiphosphat (VO)2P2O7 mit Metall(II)-oxiden (M = Co, Ni, Cu) sind die Verbindungen α-CoV2O2(PO4)2 (P21/c, a = 6,310(1) Å, b = 7,275(1) Å, c = 7,441(2) Å, β = 90,39(2)°), β-NiV2O2(PO4)2 (P21/n, a = 7,4013 Å, b = 7,2595 Å, c = 7,4230 Å, β = 121,6°) und CuV2O2(PO4)2 (Pbca, a = 7,352(1) Å, b = 12,652(1) Å, c = 14,504(2) Å) als Einkristalle gezüchtet worden. Die Cobalt- und Nickelverbindung existieren jeweils in zwei Modifikationen (α, β). Die Modifikationen β-CoV2O2(PO4)2 (isotyp zu NiTi2O2(PO4)2), Lipscombit/Lazulit Familie, P21/c, a = 7,268(1) Å, b = 7,2749(6) Å, c = 7,455(1) Å, β = 120,17(1)°) und α-NiV2O2(PO4)2 (isotyp zu α-CoV2O2(PO4)2, P21/c, a = 6,2988(9) Å, b = 7,231(1) Å, c = 7,429(1) Å, β = 90,38(1)°) wurden nur als Pulver erhalten. Eine reversible Umwandlung zwischen α «β wurde nicht beobachtet. Bei Versuchen zur Darstellung gemischter Vanadium(IV)-oxidphosphate wurde die neue Verbindung Fe2(VO)(PO4)(P2O7) (P21/m, Z = 2, a = 8,810(5) Å, b = 5,179(3) Å, c = 10,418(6) Å, β = 112,69(4)) erhalten. Die Einkristallstrukturanalyse zeigt, dass es sich um eine Verbindung mit Strukturfragmenten aus dem Lipscombit/Lazulit-Strukturtyp handelt. Katalytische Messungen an den neuen Verbindungen für die selektive Oxidation von n-Butan zu Maleinsäureanhydrid, wurden im Rahmen einer Hochschul-Industrie-Kooperation, von der BASF AG durchgeführt. Die Auswertung der Tests zeigt, dass die neu erhaltenen Verbindungen V4O3(PO4)3, CrV3O3(PO4)3, FeV3O3(PO4)3, CoV2O2(PO4)2, NiV2O2(PO4)2 und CuV2O2(PO4)2 alle katalytisch aktiv sind. Eine vergleichbare Ausbeute und Selektivität an MSA wie die des Standardkatalysators (VO)2P2O7 wird jedoch nicht erreicht. Die neu erhaltenen Verbindungen sind Produkte aus Vanadyldiphosphat mit Oxiden von Metallen welche als Promotoren Verwendung finden. Die neu erhaltenen Oxidphosphate sind mögliche Katalysatoren für die Partialoxidation von Kohlenwasserstoffen. Die Kenntnis ihrer Existenz stellt auch einen Beitrag zur Klärung der komplizierten Phasenverhältnisse von promoviertem Vanadyldiphosphat-katalysator dar
Additional file 2: of Benzylserine inhibits breast cancer cell growth by disrupting intracellular amino acid homeostasis and triggering amino acid response pathways
No full textFigure S1. Combined LAT1 and ASCT2 inhibition does not recapitulate the effects of BenSer. Relative cell viability measured by MTT assay in MCF-7 (A) and HCC1806 (B) cells cultured for 3 days in the presence or absence of 10 mM BCH and 1 mM GPNA. Data represent mean ± SEM of at least three independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; 2-way ANOVA. Figure S2. Expression of putative BenSer targets in breast cancer cell lines and patient samples. A, gene expression (mRNA log2 values) of LAT common heavy chain (SLC3A2) and LAT transporters (LAT3/SLC43A1, LAT4/SLC43A2), was analysed in all breast cancer cell lines (n = 55) included in The Cancer Cell Line Encyclopedia (TCCLE). Grouped data are plotted as box-and-whisker plots (max to min), with log2 mRNA expression in MCF-7 (red), HCC1806 (blue) and MDA-MB-231 (MDA-231) cells overlaid as individual data points. B, mRNA expression (log2 values) of SLC3A2 (B), SLC43A1 (C) and SLC43A2 (D), in the METABRIC dataset (n = 2509). Data were grouped into the “PAM50 + Claudin-low” subtypes based on clinical attribute data retrieved from www.cbioportal.org / and are plotted as box-and-whisker plots (Tukey). Figure S3. Intracellular levels of amino acids that are not affected by BenSer treatment. Intracellular levels of glutamate (A), lysine (B), arginine (C), and tryptophan (D) measured in MCF-7, HCC1806 and MDA-MB-231 (MDA231) cells after 14 h incubation in the presence or absence of 10 mM BenSer. Data are normalised to cellular protein content and expressed as a fold-change compared to Control. Data represent mean ± SEM of two independent experiments performed in triplicate. For (D), p-value shown was calculated with unpaired student’s t-test. Figure S4. BCH treatment reduces OCR. Oxygen consumption rate (OCR; A-F) and extracellular acidification rate (ECAR; G-L) in MCF-7, HCC1806 and MDA-MB-231 cells treated in the presence or absence of 10 mM BCH were assessed using a Seahorse Mito Stress Test. Data represent mean ± SEM of 3–4 independent experiments performed in triplicate. Average basal OCR and ECAR measurements were then plotted against each other for each treatment condition (M-O). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; unpaired student’s t-test. (PDF 2866 kb
Targeting glutamine transport to suppress melanoma cell growth
No full textAmino acids, especially leucine and glutamine, are important for tumor cell growth, survival and metabolism. A range of different transporters deliver each specific amino acid into cells, some of which are increased in cancer. These amino acids consequently activate the mTORC1 pathway and drive cell cycle progression. The leucine transporter LAT1/4F2hc heterodimer assembles as part of a large complex with the glutamine transporter ASCT2 to transport amino acids. In this study, we show that the expression of LAT1 and ASCT2 is significantly increased in human melanoma samples and is present in both BRAF (C8161 and WM852) and BRAF mutant (1205Lu and 451Lu) melanoma cell lines. While inhibition of LAT1 by BCH did not suppress melanoma cell growth, the ASCT2 inhibitor BenSer significantly reduced both leucine and glutamine transport in melanoma cells, leading to inhibition of mTORC1 signaling. Cell proliferation and cell cycle progression were significantly reduced in the presence of BenSer in melanoma cells in 2D and 3D cell culture. This included reduced expression of the cell cycle regulators CDK1 and UBE2C. The importance of ASCT2 expression in melanoma was confirmed by shRNA knockdown, which inhibited glutamine uptake, mTORC1 signaling and cell proliferation. Taken together, our study demonstrates that ASCT2-mediated glutamine transport is a potential therapeutic target for both BRAF and BRAF melanoma. What's new? The kinase mTORC1 can prevent cancer cells from undergoing apoptosis. Amino acids, especially leucine and glutamine, activate the mTORC1 signaling pathway. In this study, the authors found that expression of the amino acid transporters LAT1 and ASCT2 is significantly increased in melanoma cells. When they added benzyl serine (BenSer) or short hairpin RNAs to block ASCT2 in these cells, glutamine and leucine transport was decreased. This, in turn, inhibited mTORC1 signaling and cell-cycle progression. Thus, the LAT1/ASCT2 complex may be a valuable therapeutic target for melanoma
Performance of a highly loaded two stage axial-flow fan
No full textA two-stage axial-flow fan with a tip speed of 1450 ft/sec (442 m/sec) and an overall pressure ratio of 2.8 was designed, built, and tested. At design speed and pressure ratio, the measured flow matched the design value of 184.2 lbm/sec (83.55kg/sec). The adiabatic efficiency at the design operating point was 85.7 percent. The stall margin at design speed was 10 percent. A first-bending-mode flutter of the second-stage rotor blades was encountered near stall at speeds between 77 and 93 percent of design, and also at high pressure ratios at speeds above 105 percent of design. A 5 deg closed reset of the first-stage stator eliminated second-stage flutter for all but a narrow speed range near 90 percent of design
Photointerpreter Evaluation Of Hyperstereographic Forward Looking Infrared (Flir) Sensor Imagery
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MENTAL FUNCTION AND GROWTH IN CHILDREN WITH EARLY (E) VS. LATE (L) ONSET END-STAGE LIVER DISEASE (ESLD)
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