Anticancer agents interacting with membrane glucose transporters

The altered metabolism observed in cancer cells generally consists of increased glucose uptake and glycolytic activity. This is associated with an overexpression of glucose transporter proteins (GLUTs), which facilitate glucose uptake across the plasma membrane and play a crucial role in the survival of cancer cells. Therefore, GLUTs are considered as suitable targets for treatment of cancer. Herein we review some of the most relevant GLUT inhibitors that have been recently developed as prospective anticancer agents

Identification of LDH-A as a therapeutic target for cancer cell killing via (i) p53/NAD(H)-dependent and (ii) p53 independent pathways

Most cancer cells use aerobic glycolysis to fuel their growth. The enzyme lactate dehydrogenase-A (LDH-A) is key to cancer’s glycolytic phenotype, catalysing the regeneration of nicotinamide adenine dinucleotide (NAD þ ) from reduced nicotinamide adenine dinucleotide (NADH) necessary to sustain glycolysis. As such, LDH-A is a promising target for anticancer therapy. Here we ask if the tumour suppressor p53, a major regulator of cellular metabolism, influences the response of cancer cells to LDH-A suppression. LDH-A knockdown by RNA interference (RNAi) induced cancer cell death in p53 wild-type, mutant and p53-null human cancer cell lines, indicating that endogenous LDH-A promotes cancer cell survival irrespective of cancer cell p53 status. Unexpectedly,however,weuncoveredanovelroleforp53intheregulationofcancercellNADþ anditsreducedformNADH.Thus, LDH-A silencing by RNAi, or its inhibition using a small-molecule inhibitor, resulted in a p53-dependent increase in the cancer cell ratioofNADH:NADþ.Thiseffectwasspecificforp53þ/þ cancercellsandcorrelatedwith(i)reducedactivityofNADþ-dependent deacetylase sirtuin 1 (SIRT1) and (ii) an increase in acetylated p53, a known target of SIRT1 deacetylation activity. In addition, activation of the redox-sensitive anticancer drug EO9 was enhanced selectively in p53 þ / þ cancer cells, attributable to increased activity of NAD(P)H-dependent oxidoreductase NQO1 (NAD(P)H quinone oxidoreductase 1). Suppressing LDH-A increased EO9-inducedDNAdamageinp53þ/þ cancercells,butimportantlyhadnoadditiveeffectinnon-cancercells.Ourresultsidentifya unique strategy by which the NADH/NADþ cellular redox status can be modulated in a cancer-specific, p53-dependent manner and we show that this can impact upon the activity of important NAD(H)-dependent enzymes. To summarise, this work indicates two distinct mechanisms by which suppressing LDH-A could potentially be used to kill cancer cells selectively, (i) through induction of apoptosis, irrespective of cancer cell p53 status and (ii) as a part of a combinatorial approach with redox-sensitive anticancer drugs via a novel p53/NAD(H)-dependent mechanism

Thermal Kinetic Inductance Detectors for Millimeter-Wave Astrophysics

Thermal Kinetic Inductance Detectors (TKIDs) combine the excellent noise performance of traditional bolometers with a radio frequency (RF) multiplexing architecture that enables the large detector counts needed for the next generation of millimeter-wave instruments. Here we present dark prototype TKID pixels that demonstrate a noise equivalent power NEP = 2×10⁻¹⁷√W/Hz with a 1/f knee at 0.1 Hz, suitable for background-limited noise performance at 150 GHz from a ground-based site. We discuss the optimizations in the device design and fabrication techniques to realize optimal electrical performance and high quality factors at a bath temperature of 250 mK

Laser Marking of Titanium Coating for Aerospace Applications

Abstract In the aerospace industry, in order to ensure the identification and the traceability of the products, high repeatability, non-invasive and durable marking processes are required. Laser marking is one of the most advanced marking technologies. Compared to traditional marking processes, like punches, microdot, scribing or electric discharge pencil etcher, laser marking offers several advantages, such us: non-contact working, high repeatability, high scanning speed, mark width comparable to the laser spot dimension, high flexibility and high automation of the process itself. In order to assure the mark visibility for the component lifetime, an appropriate depth of the mark is required. In this way, a stable behaviour is ensured also when the component operates in aggressive environments (i.e. in presence of oxidation, corrosion and wear phenomena). The mark depth is strongly affected by the laser source kind and by the process parameters, such us average power, pulse frequency and scanning speed. Moreover, an excessive mark penetration could cause stress concentrations and reduce the fatigue life of the component. Consequently, an appropriate selection of the process parameters is required in order to assure visibility and to avoid excessive damage. Cold Spray Deposition (CSD) is a relative new technology that allows to produce surface coatings without significant substrate temperature increasing. In aeronautics fields this technology is useful to coat materials sensible to temperature, such as solution tempered aluminum alloy, with a titanium layer. Aim of the work is to characterize the laser marking process on CSD Ti coating, in order to study the influence of the laser marking process parameters (pulse power and scanning speed), on the groove geometry of the marking. The experimental marking tests were carried out through a 30 W MOPA Q-Switched Yb:YAG fibre laser; under different process conditions. The groove geometry was measured through a HIROX HK9700 optical microscope. The results showed the effectiveness of the laser process to produce high quality marks on the titanium layer. Moreover, a correlation between the process parameters and the mark's geometry was clearly observed

Inhibition of NF-κB activation sensitizes U937 cells to 3′-azido-3′-deoxythymidine induced apoptosis

In this study, we investigated molecular mechanisms underlying low susceptibility to apoptosis induced by the nucleoside analog azidothymidine (AZT) and the role of nuclear factor-κB (NF-κB) activation in these phenomena. A preliminary screening in different cell lines indicated U937 monocytic cell line as suitable to this purpose. Treatment of U937 cells even with suprapharmacological concentrations of AZT induced only moderate levels of apoptosis. Surprisingly, SuperArray analysis showed that AZT induced the transcriptional activity of both pro- and anti-apoptotic genes. Interestingly, moreover, several genes upregulated by AZT were NF-κB related. In fact, AZT, after an initial inhibition of NF-κB activation with respect to control, induced a transient, but consistent, increase in NF-κB-binding activity. Inhibition of NF-κB activation in U937 cells, stably transfected with a dominant-negative IκBα or by pharmacological treatment, sensitized them to apoptosis induced by AZT and impaired the upregulation of anti-apoptotic genes in response to AZT treatment, with respect to control cells. These results indicate that NF-κB activation by AZT has a role in protecting target cells from apoptotic cell death, improving our understanding of the toxicology and the therapeutic usage of this drug

Inhibition of IκBα phosphorylation potentiates regulated cell death induced by azidothymidine in HTLV-1 infected cells

Adult T cell leukemia/lymphoma (ATL) can be susceptible, at least transiently, to treatments with azidothymidine (AZT) plus IFNα and/or arsenic trioxide. However, the real role of AZT in this effect is still unclear. In fact, while reverse transcriptase (RT) inhibition could explain reduction of clonal expansion and of renewal of HTLV-1 infected cells during ATL progression, this effect alone seems insufficient to justify the evident and prompt decrease of the pro-viral load in treated patients. We have previously demonstrated that AZT is endowed with an intrinsic pro-apoptotic potential towards both peripheral blood mononuclear cells from healthy donors or some tumor cell lines, but this cytotoxic potential cannot be fully achieved unless IκBα phosphorylation is inhibited. Since the constitutive activation of NF-kappa B (NF-κB) appears a common biological basis of HTLV-1-infected cells, a pharmacological inhibition of IκBα phosphorylation seems a potential strategy for treating and preventing HTLV-1 related pathologies. In this study, we have demonstrated that a combination treatment with the IκBα phosphorylation inhibitor Bay 11-7085 and AZT induced increased levels of regulated cell death (RCD) by apoptosis compared to the single treatments in HTLV-1 infected cells of different origin. Importantly, levels of RCD were considerably higher in infected cells in comparison with the uninfected ones. Inhibition of NF-κB activation following the combined treatment was confirmed by analysis of both gel-shift and functional activity of the NF-κB complex proteins, p65/p52. Moreover, a transcriptional analysis revealed that the addition of Bay 11-7085 to AZT treatment in HTLV-1-infected cells modified their transcriptional profile, by inducing the upregulation of some pro-apoptotic genes together with the downregulation of some anti-apoptotic genes. Our data suggest that addition of adequate concentrations of IκBα phosphorylation inhibitor to therapeutic regimens including AZT could be a promising strategy in ATL

GLUT1 and LOX inhibitors as perspective anticancer agents tackling glucose avidity and ECM remodeling in tumors

Introduction Most cancers have large hypoxic regions, which display an increase of the glycolytic metabolism leading to the production of lactate, providing cancer cells with adequate amounts of energy and anabolites. To this end, tumor cells generally overexpress glucose transporters (GLUTs), in particular GLUT1, which results in an increased uptake of glucose to support their less efficient energy production (Warburg effect). Therefore, therapeutic interventions aimed at reducing cancer glycolysis may be implemented by several strategies, including the development of inhibitors of glucose transporters. Furthermore, extracellular matrix (ECM) remodeling is one of the key processes preluding metastatic invasion, and it is promoted by several effectors, such as lysyl oxidase (LOX), an enzyme commonly involved in extracellular matrix maturation. LOX is up-regulated by HIF-1 and plays a critical role in the development of metastasis. Therefore, LOX inhibitors may represent an additional and innovative strategy for the treatment and the prevention of metastatic cancer. Methods We have developed various classes of compounds that are able to interfere with GLUTs (Granchi et al. 2015, Tuccinardi et al. 2013) and LOX (Granchi et al. 2009) by molecular design and chemical synthesis. Their effect on cell proliferation, apoptosis, migration and other key determinants of activity were evaluated by sulforhodamine-B and luciferase assays, FACS, wound-healing assay, and Quantitative PCR. The studies were performed in seven PDAC cells, including five primary-cell-cultures and 3D co-cultures with human stellate cells, in normoxic and hypoxic conditions. Results The IC50s of the tested compounds ranged from 13.9 to 32.0 μM after 72-hour exposure. Notably, these compounds were still active in 3D co-cultures of these tumor cells with pancreatic stellate cells, which showed increased resistance to gemcitabine and are more representative of the dense stromal compartment with core hypoxic areas of this tumor type, as detected by immunohistochemical stainings. Remarkably, one compound (PGL-14) showed a synergistic interaction with gemcitabine, increasing apoptosis induction and accumulation of ROS. Furthermore, the combination of these drugs reduced cell migration and enhanced in vitro sensitivity to anoikis, suggesting the ability of these compounds to inhibit metastasis. Discussion GLUT1 inhibitors were more active in hypoxia, but still active also in normoxia. Conversely, we did not detect cytotoxic effects using the LOX-inhibitors in normoxia (at concentration until 50 μM) since they were designed as bioreductively activated prodrugs, which are therefore activated only under hypoxic conditions. However, at O2 tension of 1%, IC50s were below 10 μM. As reported previously, LOX inhibition was associated with reduction of the mRNA levels of fibronectin, suggesting that it might also have impact on the interaction of tumor cells with the stroma that are mediated by integrins and fibronectin, regulating tissue stiffness (Coppola et al. 2017). Conclusion Interventions aimed at blocking the glycolytic activity or the extracellular matrix remodeling of tumors by means of newly designed molecules proved to exert a synergistic effect with clinically approved drugs, such as gemcitabine. These results seem to support the strategy of the simultaneous GLUT/LOX-inhibition in order to further sensitize hypoxic cancer portions to chemotherapy. Bibliography C. Granchi, et al. ChemMedChem 2009, 4, 1590-1594. C. Granchi, et al. ChemMedChem 2015, 10, 1892-1900. T. Tuccinardi, et al. Bioorg. Med. Chem. Lett. 2013, 23, 6923-6927. Coppola S, et al. Drug Resist Updat. 2017, 31, 43-51