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The aim of this study was to investigate the distribution, tolerance, and anticancer and antiviral activity of Zn-based physiometacomposites (PMCs). Manganese, iron, nickel and cobalt-doped ZnO, ZnS or ZnSe were synthesized. Cell uptake, distribution into 3D culture and mice, and biochemical and chemotherapeutic activity were studied by fluorescence/bioluminescence, confocal microscopy, flow cytometry, viability, antitumor and virus titer assays. Luminescence and inductively coupled plasma mass spectrometry analysis showed that nanoparticle distribution was liver >spleen >kidney >lung >brain, without tissue or blood pathology. Photophysical characterization as ex vivo tissue probes and LL37 peptide, antisense oligomer or aptamer delivery targeting RAS/Ras binding domain (RBD) was investigated. Treatment at 25 μg/ml for 48 h showed ≥98–99% cell viability, 3D organoid uptake, 3-log inhibition of β-Galactosidase and porcine reproductive respiratory virus infection. Data support the preclinical development of PMCs for imaging and delivery targeting cancer and infectious disease.

The interfacial contact between TiO2 and graphitic carbon in a hybrid composite plays a critical role in electron transfer behavior, and in turn, its photocatalytic efficiency. Herein, we report a new approach for improving the interfacial contact and delaying charge carrier recombination in the hybrid by wrapping short single-wall carbon nanotubes (SWCNTs) on TiO2 particles (100 nm) via a hydration-condensation technique. Short SWCNTs with an average length of 125 ± 90 nm were obtained from an ultrasonication-assisted cutting process of pristine SWCNTs (1–3 μm in length). In comparison to conventional TiO2–SWCNT composites synthesized from long SWCNTs (1.2 ± 0.7 μm), TiO2 wrapped with short SWCNTs showed longer lifetimes of photogenerated electrons and holes, as well as a superior photocatalytic activity in the gas-phase degradation of acetaldehyde. In addition, upon comparison with a TiO2–nanographene “quasi-core–shell” structure, TiO2-short SWCNT structures offer better electron-capturing efficiency and slightly higher photocatalytic performance, revealing the impact of the dimensions of graphitic structures on the interfacial transfer of electrons and light penetration to TiO2. The engineering of the TiO2–SWCNT structure is expected to benefit photocatalytic degradation of other volatile organic compounds, and provide alternative pathways to further improve the efficiency of other carbon-based photocatalysts.

Peptide nanosponges of low polydispersity are spontaneously formed from trigonal supramolecular building blocks in aqueous buffers, which feature cationic and/or anionic oligopeptides (n = 5–20) and a hydrophobic unit. In contrast to classical liposomes/vesicles, nanosponges feature interwoven hydrophilic and hydrophobic nanodomains and are readily taken up by mammalian cells. Perillyl alcohol is known to be a simple, but effective small molecule drug against glioma multiforme. However, its efficacy is limited by a poor bioavailability. In order to make perillyl alcohol bioavailable, two nanosponges consisting of 10 aspartates, to which perillyl alcohol is attached by means of an ester bond, and 20 lysines or arginines (type (D-POH)10K20 and (D-POH)10R20) were synthesized, purified, and characterized by dynamic light scattering (DLS) and atomic force microscopy (AFM). These nanosponges were then tested in cell cultures of murine glioma cells (GL26) and murine neural progenitor cells (NPC) because the latt...

Red blood cells (RBCs) are the natural resident of the vascular lumen, therefore delivery of any agents within the vascular lumen could benefit by unique natural transporting features of RBCs. RBCs continuously circulate for ∼100 days before being sequestered in the spleen, they only extravasate at sites of vascular hemorrhage. Taking advantages of these features, we engineered RBC as a carrier in order to design a unique delivery system capable of delivering X-ray computed tomography (CT) contrast agents, gold nanoparticles (AuNPs), thereby acting as CT-contrast agent. A strategic membrane fusion technique was used to engineer the surface of RBC with gold nanoparticles in this in vitro study without altering its shape, size, and surface properties.

The structure of novel binary nanosponges consisting of (cholesterol-(K/D)nDEVDGC)3-trimaleimide units possessing a trigonal maleimide linker, to which either lysine (K)20 or aspartic acid (D)20 are tethered, has been elucidated by means of TEM. A high degree of agreement between these findings and structure predictions through explicit solvent and then coarse-grained molecular dynamics (MD) simulations has been found. Based on the nanosponges' structure and dynamics, caspase-6 mediated release of the model drug 5(6)-carboxyfluorescein has been demonstrated. Furthermore, the binary (DK20) nanosponges have been found to be virtually non-toxic in cultures of neural progenitor cells. It is of a special importance for the future development of cell-based therapies that DK20 nanosponges were taken up efficiently by leucocytes (WBC) in peripheral blood within 3 h of exposure. The percentage of live cells among the WBC was not significantly decreased by the DK20 nanosponges. In contrast to stem cell or leucocyte cell cultures, which have to be matched to the patient, autologous cells are optimal for cell-mediated therapy. Therefore, the nanosponges hold great promise for effective cell-based tumor targeting.

Luminol-based bioluminescence imaging allows noninvasive tracking of oxidatively active cells such as neutrophils. Luminol is given intravenously or intraperitoneally, followed by bioluminescence imaging at 425 nm. Here we describe a method for tracking neutrophil extravasation into an inflammatory site, especially focusing on mammary carcinoma.

Numerous proteases, such as matrix metalloproteinases (MMPs), cathepsins (CTS), and urokinase plasminogen activator (UpA), are dysfunctional (that is, over- or under-expressed) in solid tumors, when compared to healthy human subjects. This offers the opportunity to detect early tumors by liquid biopsies. This approach is of particular advantage for the early detection of pancreatic cancer, which is a “silent killer”. We have developed fluorescence nanobiosensors for ultrasensitive (sub-femtomolar) arginase and protease detection, consisting of water-dispersible Fe/Fe3O4 core/shell nanoparticles and two tethered fluorescent dyes: TCPP (Tetrakis(4-carboxyphenyl)porphyrin) and cyanine 5.5. Upon posttranslational modification or enzymatic cleavage, the fluorescence of TCPP increases, which enables the detection of proteases at sub-femtomolar activities utilizing conventional plate readers. We have identified an enzymatic signature for the detection of pancreatic adenocarcinomas in serum, consisting of arginase, matrix metalloproteinase-1, -3, and - 9, cathepsin-B and -E, urokinase plasminogen activator, and neutrophil elastase, which is a potential game-changer.

We have revisited the photochromic spiro-dihydroindolizine/betaine system by comparing state-of-the-art density functional theory calculations with experimental data. Time-dependent density functional theory calculations are employed to examine the transformations occurring after photoexcitation. This study confirms that photoexcitation of the spiro-dihydroindolizine leads to the formation of the cis-betaine. However, isomerization to the trans-betaine follows through a complicated and formerly unknown potential energy landscape, which consists of a network of transition states and intermediates. The available pathways across this potential energy landscape will determine the kinetics of the forward reaction from the cis-betaine to the trans-betaine and then, even more importantly, the back-reaction. Virtually all practical applications of this optical switch rely on these reactions and, therefore, occur within this landscape. Predicting the network of transition states and intermediates for substituted spiro-dihydroindolizine/betaine systems will enable the in-silico design of optical switches with enhanced performance.

The capacity of iron oxide nanocrystals to heat tissue when subjected to an alternating magnetic field (AMF hyperthermia) is shape-selective. Although iron oxide nanostructures with numerous shapes have been synthesized to date, hexagonal Fe3O4 prisms of low toxicity remained elusive. Here, we report the use of a dual ligand system permitting feasible reaction conditions to synthesize nearly perfect hexagonal Fe3O4 nanoplatelet structures, with edge length of 45 ± 5 nm and thickness of 5 to 6 nm. Their Specific Absorption Rate (SAR) is >750 W g(Fe)−1. The Fe3O4 hexagons were coated with a dopamine-based ligand to increase dispersibility in aqueous buffers. The Fe3O4 hexagons were only minimally toxic to RAW264.7 cells, which can be utilized in cell-based cancer targeting approaches.

A novel type of supramolecular aggregate, named a “nanosponge” was synthesized through the interaction of novel supramolecular building blocks with trigonal geometry. The cholesterol-(K/D) n DEVDGC) 3 -trimaleimide unit consists of a trigonal maleimide linker to which homopeptides (either K or D) of variable lengths (n = 5, 10, 15, 20) and a consensus sequence for executioner caspases (DEVDGC) are added via Michael addition. Upon mixing in aqueous buffer cholesterol-(K) n DEVDGC) 3 -trimaleimides and a 1:1 mixture of cholesterol-(K/D) n DEVDGC) 3 -trimaleimides form stable nanosponges, whereas cholesterol-(D) n DEVDGC) 3 -trimaleimide is unable to form supramolecular aggregates with itself. The structure of the novel nanosponges was investigated through explicit solvent and then coarse-grained molecular dynamics (MD) simulations. The nanosponges are between 80 nm and several micrometers in diameters and virtually non-toxic to monocyte/macrophage-like cells.

Macrophages take advantage of the antibacterial properties of copper ions in the killing of bacterial intruders. However, despite the importance of copper for innate immune functions, coordinated efforts to exploit copper ions for therapeutic interventions against bacterial infections are not yet in place. Here we report a novel high-throughput screening platform specifically developed for the discovery and characterization of compounds with copper-dependent antibacterial properties toward methicillin-resistant Staphylococcus aureus (MRSA). We detail how one of the identified compounds, glyoxal-bis(N4-methylthiosemicarbazone) (GTSM), exerts its potent strictly copper-dependent antibacterial properties on MRSA. Our data indicate that the activity of the GTSM-copper complex goes beyond the general antibacterial effects of accumulated copper ions and suggest that, in contrast to prevailing opinion, copper complexes can indeed exhibit species- and target-specific activities. Based on experimental evidence, we propose that copper ions impose structural changes upon binding to the otherwise inactive GTSM ligand and transfer antibacterial properties to the chelate. In turn, GTSM determines target specificity and utilizes a redox-sensitive release mechanism through which copper ions are deployed at or in close proximity to a putative target. According to our proof-of-concept screen, copper activation is not a rare event and even extends to already established drugs. Thus, copper-activated compounds could define a novel class of anti-MRSA agents that amplify copper-dependent innate immune functions of the host. To this end, we provide a blueprint for a high-throughput drug screening campaign which considers the antibacterial properties of copper ions at the host-pathogen interface.

The quest for renewable and cleaner energy sources to meet the rapid population and economic growth is more urgent than ever before. Being the most abundant carbon source in the atmosphere of Earth, CO2 can be used as an inexpensive C1 building block in the synthesis of aromatic fuels for internal combustion engines. We designed a process capable of synthesizing benzene, toluene, xylenes and mesitylene from CO2 and H2 at modest temperatures (T = 380 to 540 °C) employing Fe/Fe3O4 nanoparticles as catalyst. The synthesis of the catalyst and the mechanism of CO2-hydrogenation will be discussed, as well as further applications of Fe/Fe3O4 nanoparticles in catalysis.

A new application of two Negishi-type coupling reactions for the synthesis of coelenterazine is reported. The synthesis of coelenterazine in high purity on a gram scale will enable numerous approaches to bioluminescence imaging and possibly photodynamic therapy of deep-seated tumors. Coelenterazine is the substrate for several luciferases, among them Gaussia luciferase (gLuc). This synthesis starts with pyrazin-2-amine and uses inexpensive starting materials and catalysts.

The mycobacterial porin MspA is one of the most stable channel proteins known to date. MspA forms vesicles at low concentrations in aqueous buffers. Evidence from dynamic light scattering, transmission electron microscopy and zeta-potential measurements by electrophoretic light scattering indicate that MspA behaves like a nanoscale surfactant. The extreme thermostability of MspA allows these investigations to be carried out at temperatures as high as 343 K, at which most other proteins would quickly denature. The principles of vesicle formation of MspA as a function of temperature and the underlying thermodynamic factors are discussed here. The results obtained provide crucial evidence in support of the hypothesis that, during vesicle formation, nanoscopic surfactant molecules, such as MspA, deviate from the principles underlined in classical surface chemistry.

A nanobiosensor for arginase detection was designed and synthesized. It features a central dopamine-coated iron/iron oxide nanoparticle to which sulfonated cyanine 7.0 is tethered via a stable amide bond. Cyanine 5.5 is linked to the N-terminal of the peptide sequence GRRRRRRRG. Arginine (R) reacts to ornithine (O) in the presence of arginase. Based on calibration with commercially obtained arginase II, the limit of detection (LOD) is picomolar. It is noteworthy that the nanobiosensor for arginase detection does not show a fluorescence increase when incubated with the enzyme NO-reductase, which also uses arginase as substrate, but is indicative of an inflammatory response by the host to cancer and infections. Arginase activity was determined in a syngeneic mouse model for aggressive breast cancer (4T1 tumors in BALB/c mice). It was found that the arginase activity is systemically enhanced, but especially pronounced in the active tumor regions.

Two photochromic spirodihydroindolizine/betaine systems for tethering to peptides and proteins via a maleimide function have been prepared. The absorption spectra of the betaines are in the red region of the visible spectrum and in the near-IR spectral domain, which are suitable energies of light for future in vivo applications. The half-times of cyclization have been determined for both DHI/betaine systems. The findings are consistent with a thermal barrier of varying size between the transoid and cisoid conformers of the betaines.

We have transfected murine neural stem cells (NSCs) and rat umbilical cord matrix-derived stem cells (RUCMSCs) with a plasmid expressing gaussia luciferase (gLuc). These cells are engineered to secrete the luciferase. We have used gLuc containing supernatant from culturing the NSCs to perform in vitro photodynamic therapy of murine melanoma cells (B16F10), and RUCMSCs to perform in vivo PDT of lung melanomas in C57BL/6 mice. The treatment system was comprised of aminolevulic acid as a prodrug for the synthesis of the photosensitizer protoporphyrin IX, gaussia luciferase, and its' substrate coelenterazine. A significant reduction of the number of live melanoma cells in vitro and a borderline significant retardation of tumour growth in vivo was observed after coelenterazine-mediated PDT.

The targeted delivery of therapeutics to the tumor site is highly desirable in cancer treatment, because it is capable of minimizing collateral damage. Herein, we report the synthesis of a nanoplatform, which is composed of a 15 ± 1 nm diameter core/shell Fe/Fe3O4 magnetic nanoparticles (MNPs) and the topoisomerase I blocker SN38 bound to the surface of the MNPs via a carboxylesterase cleavable linker. This nanoplatform demonstrated high heating ability (SAR = 522 ± 40 W/g) in an AC-magnetic field. For the purpose of targeted delivery, this nanoplatform was loaded into tumor-homing double-stable RAW264.7 cells (mouse monocyte/macrophage-like cells (Mo/Ma)), which have been engineered to express intracellular carboxylesterase (InCE) upon addition of doxycycline by a Tet-On Advanced system. The nanoplatform was taken up efficiently by these tumor-homing cells. They showed low toxicity even at high nanoplatform concentration. SN38 was released successfully by switching on the Tet-On Advanced system. We have demonstrated that this nanoplatform can be potentially used for thermochemotherapy. We will be able to achieve the following goals: (1) Specifically deliver the SN38 prodrug and magnetic nanoparticles to the cancer site as the payload of tumor-homing double-stable RAW264.7 cells; (2) Release of chemotherapeutic SN38 at the cancer site by means of the self-containing Tet-On Advanced system; (3) Provide localized magnetic hyperthermia to enhance the cancer treatment, both by killing cancer cells through magnetic heating and by activating the immune system.

Matthew T Basel1, Sivasai Balivada1, Hongwang Wang2, Tej B Shrestha1, Gwi Moon Seo1, Marla Pyle1, Gayani Abayaweera2, Raj Dani2, Olga B Koper2, Masaaki Tamura1, Viktor Chikan2, Stefan H Bossmann2, Deryl L Troyer11Department of Anatomy and Physiology, College of Veterinary Medicine, 2Department of Chemistry, Kansas State University, Manhattan, KS, USAAbstract: Using magnetic nanoparticles to absorb alternating magnetic field energy as a method of generating localized hyperthermia has been shown to be a potential cancer treatment. This report demonstrates a system that uses tumor homing cells to actively carry iron/iron oxide nanoparticles into tumor tissue for alternating magnetic field treatment. Paramagnetic iron/iron oxide nanoparticles were synthesized and loaded into RAW264.7 cells (mouse monocyte/macrophage-like cells), which have been shown to be tumor homing cells. A murine model of disseminated peritoneal pancreatic cancer was then generated by intraperitoneal injection of Pan02 cells. After tumor development, monocyte/macrophage-like cells loaded with iron/iron oxide nanoparticles were injected intraperitoneally and allowed to migrate into the tumor. Three days after injection, mice were exposed to an alternating magnetic field for 20 minutes to cause the cell-delivered nanoparticles to generate heat. This treatment regimen was repeated three times. A survival study demonstrated that this system can significantly increase survival in a murine pancreatic cancer model, with an average post-tumor insertion life expectancy increase of 31%. This system has the potential to become a useful method for specifically and actively delivering nanoparticles for local hyperthermia treatment of cancer.Keywords: cytotherapy, pancreatic cancer, disseminated peritoneal carcinomatosis, targeted magnetic hyperthermia, nanoparticles

Hydroxyl soybean oils, also called soy polyols, are biobased chemicals designed to replace petroleum-based polyols mainly for polyurethane (PU) applications. Soy polyols are obtained by acid-catalyzed ring opening of expoxidized soybean oils or other epoxidized plant oils by nucleophilic SN2 attack of methanol. Recyclable heterogeneous catalysts are preferred for the ring-opening reactions over non-recyclable homogeneous catalysts because they minimize environmental impact. The drawbacks of current solid catalysts such as SAC 13 and Amberlite 15 are low production yield and high energy consumption. Here, we demonstrate a greener synthetic pathway of soy polyols with low energy consumption and excellent atom economy and environment (E) factor by using novel sulfamic acid-functionalized iron (iron/iron oxide core shell) nanoparticles (NPs) as a heterogeneous catalyst. The excellent selectivity of the reaction with the recyclable NPs was confirmed by 1H NMR, 1H-1H COSY NMR, and ESI-MS comparable to non-recyclable H2SO4. The synthetic route with the NPs resulted in higher product yield (almost 100%) as H2SO4 at room temperature for 30 min over the SAC 13 (83% yield at 60 °C for 60 min) and Amberlite 15 (87% yield at 60 °C for 100 min). Life cycle assessment (LCA) revealed that the NP synthetic technology for soy polyol production is superior or equal to the competing routes (H2SO4, SAC 13, and Amberlite 15 methods) with respect to 9 environmental impacts (acidification potential, ozone depletion potential, smog formation potential, global warming potential, human toxicity by ingestion, human toxicity by inhalation, persistence, bioaccumulation, and abiotic resource depletion potential).

Gene-directed enzyme prodrug therapy (GDEPT) has been investigated as a means of cancer treatment without affecting normal tissues. This system is based on the delivery of a suicide gene, a gene encoding an enzyme which is able to convert its substrate from non-toxic prodrug to cytotoxin. In this experiment, we have developed a targeted suicide gene therapeutic system that is completely contained within tumor-tropic cells and have tested this system for melanoma therapy in a preclinical model. First, we established double stable RAW264.7 monocyte/macrophage-like cells (Mo/Ma) containing a Tet-On® Advanced system for intracellular carboxylesterase (InCE) expression. Second, we loaded a prodrug into the delivery cells, double stable Mo/Ma. Third, we activated the enzyme system to convert the prodrug, irinotecan, to the cytotoxin, SN-38. Our double stable Mo/Ma homed to the lung melanomas after 1 day and successfully delivered the prodrug-activating enzyme/prodrug package to the tumors. We observed that our system significantly reduced tumor weights and numbers as targeted tumor therapy after activation of the InCE. Therefore, we propose that this system may be a useful targeted melanoma therapy system for pulmonary metastatic tumors with minimal side effects, particularly if it is combined with other treatments.

There is a significantly increased interest in using antimicrobial peptides for anticancer therapy. D-K6L9, LKLLKKLLKKLLKLL is an antimicrobial peptide that has been explored. It kills cancer cells by depolarizing their cell membranes, thus inducing apoptosis. Further modification of the peptide for increased toxicity and safe packaging into a delivery vehicle for targeted delivery is highly desired for the in vivo applications. Here, the peptide was modified with two extra amino acids (serine and alanine) at both C and N terminals, resulting in SA-LKLLKKLLKKLLKLL-AS. The sequence and structure of the modified peptide were determined by means of 2D 1H-1H -COSY, NOESY, and TOCSY-NMR spectroscopy. The 3D structure of the peptide in the solution phase was generated by CNS software using a distance constraint generated by NOE spectroscopy. The 3-D structure of SA-D-K6L9-AS is maintained, as well as the amphiphilicity required for insertion into cell membranes. This peptide was tested on the following mouse cancer cell lines: GL 26 (glioma), B16-F10 (melanoma lung metastases) and 4T1 (metastasizing breast cancer). The LC50 values of the modified peptide were found to be 0.707 µM for B16-F10, 6.237 µM for 4T1 and 1.707 µM for GL 26, which is 5- 10 fold more active than the original D-K6L9. To explore the findings using the modified peptide, SA-D-K6L9-AS tagged with a rhodamine dye was incubated with GL 26 cancer cells. Sequential confocal imaging (every 30 seconds) revealed that the peptide gets internalized into the cytoplasm in less than 5 min and then localizes in the mitochondria. This peptide is found to be toxic to neuronal stem cells and monocytes as well. To avoid the non-specific toxicity of the peptide for in vivo applications, highly mesoporous silica nanoparticles (MSN) were synthesized. The peptide was loaded into the MSN. MSN were further coated with a polysilazane as a “gift wrap” after loading the peptide. This gift wrap can hold the contents inside the MSN, showing no toxicity at 24 hours and subsequent slow release of the peptide payload into the cytoplasm within 72 hours. This gift wrapping of the highly toxic peptide into the MSN could be very useful for in vivo cancer therapy by means of targeted delivery to the cancer site with appropriate surface modification of MSN. Citation Format: Tej B. Shrestha, Jing Yu, Stefan Bossmann, Deryl Troyer. Structure determination, mode of action and safe delivery of an improved K6L9-type peptide [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3730.

We elucidated the photochromic spiro-4a,5-dihydropyrrolo[1,2-b]pyridazine/betaine (DPP/betaine) system by comparing state-of-the-art density functional theory calculations with nanosecond/millisecond UV-vis absorption spectroscopy, as well as steady-state absorption and cyclization kinetics. Time-dependent density functional theory calculations are employed to examine the transformations occurring after photoexcitation. This study shows that the photochromic spiro-4a,5-dihydropyrrolo[1,2-b]pyridazine and spiro-1,8a-dihydroindolizine (DHI) systems react according to similar pathways. However, notable differences exist. Although photoexcitation of the spiro-DPP system also leads to cis-betaines, which then isomerize to trans-betaines, we found two distinct classes of cis isomers (cis-betaine rotamer-1 and cis-betaine rotamer-2), which do not exist in spiro-1,8a-dihydroindolizine. Similar to our previous study on the spiro-DHI/betaine system, a complicated potential-energy landscape between cis and trans isomers exists in the spiro-DPP system, consisting of a network of transition states and intermediates. Because the spiro-DPP/betaine is even more complicated than the spiro-DHI/betaine system, (substituted) photochromic systems featuring a 4a,5-dihydropyrrolo[1,2-b]pyridazine functional unit will require thorough in silico design to function properly as logical gates or in devices for information storage.

Here, we report the synthesis, characterization, and efficacy study of Fe/Fe3O4-nanoparticles that were co-labeled with a tumor-homing and membrane-disrupting oligopeptide and the iron-chelator Dp44mT, which belongs to the group of the thiosemicarbazones. Dp44mT and the peptide sequence PLFAERL(D[KLAKLAKKLAKLAK])CGKRK were tethered to the surface of Fe/Fe3O4 core/shell nanoparticles by utilizing dopamine-anchors. The 26-mer contains two important sequences, which are the tumor targeting peptide CGKRK, and D[KLAKLAK]2, known to disrupt the mitochondrial cell walls and to initiate programmed cell death (apoptosis). It is noteworthy that Fe/Fe3O4 nanoparticles can also be used for MRI imaging purposes in live mammals. In a first step of this endeavor, the efficacy of this nanoplatform has been tested on the highly metastatic 4T1 breast cancer cell line. At the optimal ratio of PLFAERD[KLAKLAK]2CGKRK to Dp44mT of 1 to 3.2 at the surface of the dopamine-coated Fe/Fe3O4-nanocarrier, the IC50 value after 24 h of incubation was found to be 2.2 times lower for murine breast cancer cells (4T1) than for a murine fibroblast cell line used as control. Based on these encouraging results, the reported approach has the potential of leading to a new generation of nanoplatforms for cancer treatment with considerably enhanced selectivity towards tumor cells.

A new application of two Negishi-type coupling reactions for the synthesis of coelenterazine is reported. The synthesis of coelenterazine in high purity on a gram scale will enable numerous approaches to bioluminescence imaging and possibly photodynamic therapy of deep-seated tumors. Coelenterazine is the substrate for several luciferases, among them Gaussia luciferase (gLuc). This synthesis starts with pyrazin-2-amine and uses inexpensive starting materials and catalysts.

Polymorphonuclear neutrophils (PMNs) are the most abundant circulating blood leukocytes. They are part of the innate immune system and provide a first line of defense by migrating toward areas of inflammation in response to chemical signals released from the site. Some solid tumors, such as breast cancer, also cause recruitment and activation of PMNs and release of myeloperoxidase. In this study, we demonstrate that administration of luminol to mice that have been transplanted with 4T1 mammary tumor cells permits the detection of myeloperoxidase activity, and consequently, the location of the tumor. Luminol allowed detection of activated PMNs only two days after cancer cell transplantation, even though tumors were not yet palpable. In conclusion, luminol-bioluminescence imaging (BLI) can provide a pathway towards detection of solid tumors at an early stage in preclinical tumor models.

We and others recently identified copper resistance as important for virulence of Mycobacterium tuberculosis . Here, we introduce a high-throughput screening assay for agents that induce a copper hypersensitivity phenotype in M. tuberculosis and demonstrate that such copper-boosting compounds are effective against replicating and nonreplicating M. tuberculosis strains.

Enzyme-activated prodrugs have been investigated and sought after as highly specific, low-side-effect treatments, especially for cancer therapy. Unfortunately, excellent targets for enzyme-activated therapy are rare. Here a system based on cell delivery that can carry both a prodrug and an activating enzyme to the cancer site is demonstrated. Raw264.7 cells (mouse monocyte/macrophage-like cells, Mo/Ma) are engineered to express intracellular rabbit carboxylesterase (InCE), which is a potent activator of the prodrug irinotecan to SN38. InCE expression is regulated by the TetOn® system, which silences the gene unless a tetracycline, such as doxycycline, is present. Concurrently, an irinotecan-like prodrug, which is conjugated to dextran and can be loaded into the cytoplasm of Mo/Ma, is synthesized. To test the system, a murine pancreatic cancer model is generated by intraperitoneal (i.p.) injection of Pan02 cells. Engineered Mo/Ma are loaded with the prodrug and are injected i.p. Two days later, doxycycline was given i.p. to activate InCE, which activated the prodrug. A survival study demonstrates that this system significantly increased survival in a murine pancreatic cancer model. Thus, for the first time, a prodrug/activating enzyme system, which is self-contained within tumor-homing cells and can prolong the life of i.p. pancreatic tumor bearing mice, is demonstrated.

Our knowledge about the metabolism of alkylcyclobutanones (2-ACBs) is limited, and the lack of literature on the metabolism of 2-ACBs causes consumers to doubt the safety of irradiated foods. The objectives of this study were to evaluate the metabolism of 2-dodecylcyclobutanone (2-DCB) and identify any possible metabolite. The 2-DCB was mixed with rat S9 (postmitochondrial supernatant fraction) and beta-nicotinamide adenine dinucleotide phosphate (NADPH) in phosphate buffer (pH 7.4) and incubated for 2 h at 37 degrees C. Then, the incubation mixture was mixed with sodium sulfate and extracted with n-hexane by using a Soxhlet apparatus. The hexane extract was concentrated under nitrogen and injected into the gas chromatography-mass spectrometry (GC-MS) machine running in selective ion monitoring mode (SIM) to measure 2-DCB concentration. The hexane extract from the in vitro and in vivo studies was also derivatized with a silylation reagent and injected into a GC-MS running in full scan mode. The average percentage of 2-DCB recovered from the test incubations was 23%, compared with 50% from the controls. The GC-MS chromatograms of the derivatized samples showed a unique peak in the in vitro test incubations and in the hexane extract of the rat feces that were given 2-DCB. This peak was later identified as 2-doecylcyclobutanol.

We have revisited the photochromic spiro-dihydroindolizine/betaine (DHI/B) system applying state-of-the-art density functional theory (DFT) calculations in combination with stationary and time-resolved absorption measurements. DHI/B-systems are becoming increasingly important as potential molecular machines, molecular switches, and photoswitchable electron-acceptors. The knowledge of the exact mechanisms of ring opening and closure, as well as of the geometries of DHI and betaine can provide critical information that will enable the design of better molecular machines and optical switches. The first surprising result concerns the electronic structure of the betaines, which is quite different than commonly assumed. The photochemical ring opening of DHI's to betaines is a conrotatory 1,5 electrocyclic reaction, whereas the thermal ring-closing occurs in the disrotatory mode. According to our results, the electrocyclic back reaction of the betaines to the DHI is NOT rate determining, as previously thought, but instead the kinetics are dictated by the cis-trans-isomerization of the betaine.

Photodynamic therapy (PDT) is a cancer treatment that uses a photosensitizer and a specific wavelength of light. When tumor cells which have absorbed photosensitizer are exposed to the correct wavelength of light, reactive oxygen species are generated, resulting in tumor cell death. Poor tissue penetration of light is a major limitation in PDT, restricting its use to treatment of localized tumors. Light generation at the tumor area might increase the effectiveness of PDT and can expand its use for metastatic tumors. Infiltration of tumor-activated polymorphonuclear neutrophils (PMNs) produces luminescence in the presence of luminol; this bioluminescence has been used for tumor detection in pre-clinical trials. Based on this rationale, we hypothesized that luminol-based bioluminescence can cause targeted PDT in breast adenocarcinoma tumors in the presence of the photosensitizer 5-aminolevulinic acid (ALA). To test this hypothesis, BALB/c mice were transplanted with 4T1 mammary adenocarcinoma cells to establish a breast adenocarcinoma model. After tumor formation, ALA and luminol were administered to mice through intraperitoneal and intravenous routes, respectively. This treatment regimen was repeated six times and ALA alone/luminol alone/saline treated tumor-bearing mice were used as controls. Relative differences in the increase of tumor volume and final tumor weights were analyzed to test the treatment hypothesis. Analysis of the data showed that treatment with a combination of luminol and ALA as well as treatment with luminol alone results in breast adenocarcinoma tumor growth attenuation. This study gives evidence for the antitumor activity of luminol on breast adenocarcinoma, possibly through PDT. Citation Format: Hamad S. Alshetaiwi, Tej B. Shrestha, Sivasai Balivada, Matthew T. Basel, Marla Pyle, Hongwang Wang, Stefan H. Bossmann, Deryl L. Troyer. Luminol-based in situ photodynamic therapy for breast adenocarcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4920. doi:10.1158/1538-7445.AM2014-4920

Enzyme activated prodrugs have been investigated and sought after as highly-specific, low side effect treatments, especially for cancer therapy. We synthesized an SN38-dextran prodrug and utilized it in a cell delivery system that can carry both the prodrug and an activating enzyme to the cancer site. For delivery of our prodrug, we engineered Raw264.7 cells (mouse monocyte/macrophage like cells, Mo/Ma) to express intracellular rabbit carboxylesterase (InCE), which cleaves the prodrug to activate SN38. InCE expression was regulated by the TetOn® system, which silences the gene unless a tetracycline, such as doxycycline is present. To test the system, a murine pancreatic cancer model was generated by intraperitoneal (i.p.) injection of Pan02 cells. Engineered Mo/Ma cells were loaded with the SN38-dextran prodrug and were injected i.p. into the mice. Two days following injection, doxycycline was given i.p. to activate the InCE, which in turn activates the prodrug into active SN38. A survival study demonstrated that this system significantly increased survival in a murine pancreatic cancer model, with an average post-diagnosis life expectancy increase of 20%. Thus, for the first time, a prodrug/activating enzyme system self-contained within tumor-homing cells has been demonstrated that can significantly prolong the life of i.p. pancreatic tumor bearing mice. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-199. doi:10.1158/1538-7445.AM2011-LB-199

Hyperthermia has been a method for cancer treatment for several decades now because cancer cells are slightly more susceptible to hyperthermia than healthy cells. Unfortunately, whole body hyperthermia has prohibitive side effects limiting its use or usefulness. Local hyperthermia, directed only to tumor tissue, could alleviate this problem and prove to be a potent cancer treatment. One method of generating local hyperthermia is to deliver magnetic nanoparticles to the tumor site and then generate heat using an alternating magnetic field (AMF). Here we demonstrate a system that uses tumor homing cells to actively carry iron/iron oxide nanoparticles into tumor tissue for AMF treatment. Paramagnetic iron/iron oxide nanoparticles were synthesized that absorb and convert AMF energy into heat very efficiently. These nanoparticles were loaded into Raw264.7 cells (mouse monocyte/macrophage like cells, Mo/Ma), that we have previously shown to be tumor homing cells. Test showed that the nanoparticles loaded at high concentration in the cells with very low toxicity. To test the system, a murine pancreatic cancer model was generated by injection of Pan02 cells i.p. After tumor development, Mo/Ma loaded with iron/iron oxide nanoparticles were injected i.p. and allowed to crawl into the tumor. Three days after injection, mice were exposed to an alternative magnetic field for twenty minutes to cause the cell-delivered nanoparticles to generate heat. This treatment regimen was repeated three times. A survival study demonstrated that this system can significantly increase survival in a murine pancreatic cancer model, with an average post-diagnosis life expectancy increase of 33%. Thus, for the first time, a cell-delivered nanoparticle system for generating localized hyperthermia has been demonstrated that can significantly prolong the life of i.p. pancreatic tumor bearing mice. This system has the potential to become a useful method for specifically and actively delivering nanoparticles for local hyperthermia treatment of cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-205. doi:10.1158/1538-7445.AM2011-LB-205

A new taxane derivative, 2-deacetoxytaxinine B (1), has been isolated from Taxus wallichiana, along with β-sitosterol, sciadopitysin, and methyl β-orcinolcarboxylate.