A Short-Lived but Highly Cytotoxic Vanadium(V) Complex as a Potential Drug Lead for Brain Cancer Treatment by Intratumoral Injections

The chemistry and short lifetimes of metal-based anti-cancer drugs can be turned into an advantage for direct injections into tumors, which then allow the use of highly cytotoxic drugs. The release of their less toxic decomposition products into the blood will lead to decreased toxicity and can even have beneficial effects. We present a ternary V^V complex, 1 ([VOL¹L²], where L¹ is N-(salicylideneaminato)-N′-(2-hydroxyethyl)ethane-1,2-diamine and L² is 3,5-di-tert-butylcatechol), which enters cells intact to induce high cytotoxicity in a range of human cancer cells, including T98g (glioma multiforme), while its decomposition products in cell culture medium were ≈8-fold less toxic. 1 was 12-fold more toxic than cisplatin in T98g cells and 6-fold more toxic in T98g cells than in a non-cancer human cell line, HFF-1. Its high toxicity in T98g cells was retained in the presence of physiological concentrations of the two main metal-binding serum proteins, albumin and transferrin. These properties favor further development of 1 for brain cancer treatment by intratumoral injections.     

A Short‐Lived but Highly Cytotoxic Vanadium(V) Complex as a Potential Drug Lead for Brain Cancer Treatment by Intratumoral Injections

The chemistry and short lifetimes of metal‐based anti‐cancer drugs can be turned into an advantage for direct injections into tumors, which then allow the use of highly cytotoxic drugs. The release of their less toxic decomposition products into the blood will lead to decreased toxicity and can even have beneficial effects. We present a ternary V^V complex, 1 ([VOL¹L²], where L¹ is N‐(salicylideneaminato)‐N′‐(2‐hydroxyethyl)ethane‐1,2‐diamine and L² is 3,5‐di‐tert‐butylcatechol), which enters cells intact to induce high cytotoxicity in a range of human cancer cells, including T98g (glioma multiforme), while its decomposition products in cell culture medium were ≈8‐fold less toxic. 1 was 12‐fold more toxic than cisplatin in T98g cells and 6‐fold more toxic in T98g cells than in a non‐cancer human cell line, HFF‐1. Its high toxicity in T98g cells was retained in the presence of physiological concentrations of the two main metal‐binding serum proteins, albumin and transferrin. These properties favor further development of 1 for brain cancer treatment by intratumoral injections.     

A novel electrochemical method to detect cell surface carbohydrates and target cells

Glycosylation of cell surfaces is a critical factor in many biological processes; however, the lack of effective analytical tools for the detection of cell surface carbohydrates has been the bottleneck for probing into the processes. In this paper, a novel electrochemical method is presented for the analysis of cell surface carbohydrates, which can be also used to detect the target cells. Firstly, 5-hydroxy-3-hexanedithiol-1,4-naphthoquinone (JUG_thio), the electrochemical reporter, and anti-selectin aptamer are successively modified onto the surface of a gold electrode. Different concentrations of intestinal human colon adenocarcinoma (LS180) cells are employed as the target cells for this study. Consequently, the specific carbohydrates on the surfaces of LS180 cells and anti-selectin aptamers will compete for combination with selectin in the system. As a result, the oxidation signal of JUG_thio is changed and the detection of the cell surface carbohydrates can be achieved easily and sensitively. Furthermore, the proposed method can be used to specifically detect LS180 cells in a wide concentration range, from 10³ to 10⁷ cells/mL, with a good linear relationship and low detection limit, which might be promising for the diagnosis of cancer and some other diseases in the future.     

A peptide-derived strategy for specifically targeting the mitochondria and ER of cancer cells: a new approach in fighting cancer

An effective anti-cancer therapy should exclusively target cancer cells and trigger in them a broad spectrum of cell death pathways that will prevent avoidance. Here, we present a new approach in cancer therapy that specifically targets the mitochondria and ER of cancer cells. We developed a peptide derived from the flexible and transmembrane domains of the human protein NAF-1/CISD2. This peptide (NAF-1^44-67) specifically permeates through the plasma membranes of human epithelial breast cancer cells, abolishes their mitochondria and ER, and triggers cell death with characteristics of apoptosis, ferroptosis and necroptosis. In vivo analysis revealed that the peptide significantly decreases tumor growth in mice carrying xenograft human tumors. Computational simulations of cancer vs. normal cell membranes reveal that the specificity of the peptide to cancer cells is due to its selective recognition of their membrane composition. NAF-1^44-67 represents a promising anti-cancer lead compound that acts via a unique mechanism.

An effective anti-cancer therapy should exclusively target cancer cells and trigger in them a broad spectrum of cell death pathways that will prevent avoidance.     

Coupling chemiluminescence with capillary electrophoresis to analyze single human red blood cells

In this paper, we describe a new method for determination of hemoglobin of single red blood cells by coupling chemiluminescence with capillary electrophoresis (CL-CE). The chemiluminescent detection is based on the catalytic effects of hemoglobin on the luminol-hydrogen peroxide reaction. The conditions of chemiluminescent reaction and capillary electrophoresis were investigated. Hemoglobin in human blood samples was detected with the present method, the linear range from 1.7 μg mL⁻¹ to 6.8 μg mL⁻¹ was tested, and the correlation coefficient of 0.997 and low detection limit of 0.17 μg mL⁻¹ (approximately 2.2 pg, S/N = 3) were obtained. Cell injection procedure was improved, and the method was successfully used to determine hemoglobin of single red blood cells and the statistical result of the average content of hemoglobin in 26 human red blood cells was 23.6 pg. Compared to other current methods, CE with CL system is simple, sensitive and will become an attractive alternative method for single cell analysis.     

DIRECT EXPOSURE OF MANNALIAN CELLS TO PURE EXOGENOUS SINGLET OXYGEN (ΔgO2

Mammalian cells attached to membrane filters or deposited on filters without attachment were exposed to gas-phase singlet oxygen (¹O₂) in the absence of any other reactants. Cells were exposed in a monolayer or less, in the absence of external medium, during steady-state ¹O₂ generation, ensuring that singlet oxygen impinged directly and equally on all cells simultaneously. The current methodology for cell exposure ensures that ¹O₂ is initially the only reactive species to which the cells are exposed. Results seen with this system can therefore be attributed solely and unambiguously to events initiated by ¹O₂. Further, all cells in the sample receive the same magnitude of exposure per surface area per time interval, which supports calculations of the amount of ¹O₂ required for irreversible cell damage, based on measured ¹O₂ flux and exposed cell surface area. Exposure to pure ¹O₂ irreversibly damaged a variety of cell types, including rat basophilic leukemia, human squamous carcinoma and Chinese hamster lung fibroblast cell lines, and murine primary hepatocytes. Cell survival curves following exposure to ¹O₂ followed apparent first-order kinetics. A large number of singlet oxygen collisions (? 10¹²-10¹³) were required to inactivate a cell, on average, indicating a low probability that singlet oxygen collision will reduce cell survival. Regardless of cell type or the survival endpoint measured, lethal toxicity required a fairly constant number of ¹O₂ collisions per cell. This poses a serious caveat in the assignment of causality in correlating ¹O₂-initiated cellular damage with mechanism of death, i.e. most damage observed will not be related to death. The importance of various toxic effects of ¹O₂, whether lethal or nonlethal, will depend on the magnitude of exposure and therefore on the context in which exposure occurs.     

Design and synthesis of a second-generation ligand-tethered calcium indicator for plant cell biology based on the fundamental analyses of the structure and physical property

Calcium ion (Ca²⁺) is one of the most important second messengers. However, conventional Ca²⁺ indicators cannot be applied in plant cells. In previous paper, we developed the first-generation protein-ligand tethered calcium indicator that can be applied for living plant cells.Here, we will report the development of second-generation indicator based on the detailed examination on physical properties of the first-generation to improve the drawbacks. Through the examination, we also found that cell permeability of the probe is strongly affected by their aggregation properties. Our findings will provide new strategy for the design of synthetic indicators.     

Synthesis and Antiproliferatory Activities Evaluation of Multi-Substituted Isatin Derivatives

A series of multi-substituted isatin derivatives were synthesized using the powerful Sandmeyer reaction. The structures of these derivatives were confirmed by ¹H-NMR, ¹³C-NMR, and HR-MS. Inhibition of proliferation activities of these derivatives against human leukemia cells (K562), human hepatocellular carcinoma cells (HepG2) and human colon carcinoma cells (HT-29) were evaluated in vitro using the MTT assay. Among the series, compound 4l exhibited strong antiproliferatory activities against K562, HepG2 and HT-29 cells with IC₅₀ values of 1.75, 3.20, and 4.17 μM, respectively. The morphological, growth inhibitory and apoptosic effects of compound 4l in K562 cells, wound healing effect in HepG2 cells, and tube formating effect in matrix gel of HUVEC cells were evaluated consequently. All results indicated that compound 4l could be used as a potential antitumor agent in further investigations.     

Detection and Prevention of Ocular Phototoxicity of Ciprofloxacin and Other Fluoroquinolone Antibiotics†

Fluoroquinolone (FLQ) drugs are a potent family of antibiotics used to treat infections including ocular infections. To determine if these antibiotics may be phototoxic to the eye, we exposed human lens epithelial cells to 0.125–1 mm FLQs (ciprofloxacin [Cipro], lomefloxacin [Lome], norfloxacin [Nor] and ofloxacin [Ofl]), the precursor quinolone nalidixic acid (Nalid) and UVA radiation (2.5 J cm⁻²). Based on fluorescence confocal microscopy, FLQs are diffused throughout the cytoplasm and preferentially located in the lysosomes of lens epithelial cells. Neither FLQ exposure alone nor UVA exposure alone reduced cell viability. However, with exposure to UVA radiation the FLQs studied (Cipro, Nor, Lome and Ofl) induced a phototoxic reaction that included necrosis, apoptosis, loss of cell viability as measured by MTS, and membrane damage as determined by the lactate dehydrogenase assay. Both Nalid and all FLQs studied (Cipro, Nor, Lome and Ofl) photopolymerized the lens protein α-crystallin. Phototoxic damage to lens epithelial cells and/or α-crystallin will lead to a loss of transparency of the human lens. However, if precautions are taken to filter all UV radiation from the eye while taking these antibiotics, eye damage may be prevented.     

Synthesis of [123I] iodoantipyrine to study the high-LET characteristics of Auger electrons in mammalian cells

4-Iodoantipyrine was synthesised from phenazone, labeled with¹²³I and administered to cells in culture. 4-[¹²³I]iodoantipyrine carries the radionuclide across the cell membrane allowing one to study the biological effects of the very short ranged Auger electrons emitted by this isotope. The formulation used to prepare this compound proves to be free of reagents that may have an adverse effect on the mitotic activity of cells in culture. By observing micronuclei frequencies in human lymphocytes and CHO-K1 cells the high-LET characteristics of Auger electrons could be demonstrated. Compared to extracellular disintegrations from [¹²³I]NaI and¹²³I-human serum albumin, a substantial reduction in the variation in radiosensitivity of these cell types was noted when treated with 4-[¹²³I] iodoantipyrine.     

Harmless glucose-modified ruthenium complexes suppressing cell migration of highly invasive cancer cell lines

Glucose-substituted ruthenium complexes [(η⁶-benzyl-glucose)RuCp*]⁺Cl⁻, where Cp* = η⁵-C₅Me₅; benzyl-glucose = peracetylated benzyl β-d -glucopyranoside ( 1 ), benzyl β-d -glucopyranoside ( 2 ), have been prepared and used as efficient antimigration and anti-invasive agents against metastatic breast cancer cells (MDA-MB-231) and cisplatin-resistant ovarian cancer cells (SK-OV-3). In addition, these complexes were found to be essentially non-toxic against non-cancerous human kidney cells (HEK293).     

Bioorganic Chemistry of Hypothiocyanite

Abstract

Hypothiocyanite (OSCN^?) plays an important role in the human host defense system as a nonimmunological antimicrobial agent. Although many conjugate reactions of proteins have been attributed to OSCN^?, there is little precedence for such reactions in small-molecule chemistry. We will discuss the derivative species that are in equilibrium with OSCN^?, including hypothiocyanous acid (HOSCN), thiocyanogen [(SCN) ₂ ], and trithiocyanate [(SCN) ₃ ^?], the first organic derivatives of this mixture to be fully characterized, and we will describe a new method of synthesizing hypothiocyanite.     

A miniature cytometry platform for capture and characterization of T-lymphocytes from human blood

Given the clinical and diagnostic importance of blood analysis, there is considerable interest in developing novel miniature devices for rapid characterization of blood constituents. The present paper describes development of a miniature cytometry platform aimed at analysis of T-lymphocytes from peripheral human blood. Microarrays of T-cell-specific antibodies (Abs), including anti-CD3, -CD4, -CD8 and mouse IgG (negative control) were robotically printed onto glass slides coated with a non-fouling poly(ethylene glycol) (PEG) hydrogel. The glass substrates containing Ab arrays were incubated with 100 μL of red blood cell (RBC)-depleted whole human blood for 15 min and then exposed to a controlled shear of ∼2 dyn cm⁻² for additional 10 min. This process led to the removal of non-specific leukocytes and “development” of patterns of T-cells captured on the Ab spots. The immunofluorescent staining of the surface-bound cells revealed the presence of purified CD4⁺ and CD8⁺ T-cells (purity >94%) on their respective Ab spots. Importantly, the proportions of CD4⁺ and CD8⁺ T-cells captured on the Ab spots correlated closely (R² − 0.9) with flow cytometry analysis of T-cell subsets in blood. Overall, this cytometry platform allowed to rapidly (under 30 min) capture pure T-cell subsets from minimally processed human blood. Significantly, our device provided quantitative information about subset abundance solely based on the location of cells within the microarray. This cytometry platform is envisioned as a miniature immunology tool for determination of T-cell phenotype and will have immediate applications in HIV diagnostics and research.     

Evaluation of the 99mtechnetium labelling effect on Pseudomonas aeruginosa surface properties

Gamma emitter isotopes present some advantages over beta emitters as radioisotopic microbial labels. The labelling of bacteria with ^99mtechnetium (^99mTc) has recently been described. However, it was not ascertained weether the labelling process modifies microbial physicochemical surface properties important in the interaction between bacteria and eukaryotic cells. In the present study, we evaluated the effect of the labelling process on Pseudomonas aeruginosa surface charge, hydrophobicity, adherence to human buccal epithelial cells and phagocytosis by human leukocytes. No significant differences in electrophoretic mobility or cationized ferritin distribution was observed on the cell surface of labelled and unlabelled bacteria. ^99mTc labelling did not modify the hydrophobicity adhesiveness or phagocytosis of P. aeruginosa. It is concluded that bacterial labelling with ^99mTc may be a useful method for the numeration of bacteria and the analysis of their functional properties.     

Introduction of Adonis aestivalis as a new source of effective cytotoxic cardiac glycoside

Cardiac glycosides are used for treatment of irregular heartbeats, cardiac arrhythmia and congestive heart failures. In this research, digitoxin as a cardiac glycoside was identified and isolated for the first time in the world from Adonis aestivalis and investigated for its cytotoxic activity against cervical cancer cell (HeLa) lines and human lymphocytes by MTT test. Digitoxin extracted from the aerial parts of the plant collected from west of Iran and purified by column and thin layer chromatographic techniques. The structure of isolated cardiac glycoside was identified by IR, ¹H NMR and ¹³C NMR methods and so the presence of digitoxin was established. The half maximal inhibitory concentration values for cervical cancer and lymphocyte cells were obtained to be 5.62 and 412.94 μg/mL. The results of this study introduced the new resource of digitoxin which has considerable cytotoxic effects against HeLa cancer cells but did not damage normal human lymphocyte cells.     

Binding of Chromium(III) to Transferrin Could Be Involved in Detoxification of Dietary Chromium(III) Rather than Transport of an Essential Trace Element

Cr^III binding to transferrin (Tf; the main Fe^III transport protein) has been postulated to mediate cellular uptake of Cr^III to facilitate a purported essential role for this element. Experiments using HepG2 (human hepatoma) cells, which were chosen because of high levels of the transferrin receptor, showed that Cr^III binding to vacant Fe^III‐binding sites of human Tf effectively blocks cellular Cr^III uptake. Through bio‐layer interferometry studies of the Tf cycle, it was found that both exclusion and efflux of Cr₂^IIITf from cells was caused by 1) relatively low Cr₂Tf affinity to cell‐surface Tf receptors compared to Fe₂Tf, and 2) disruption of metal release under endosomal conditions and post‐endosomal Tf dissociation from the receptor. These data support mounting evidence that Cr^III is not essential and that Tf binding is likely to be a natural protective mechanism against the toxicity and potential genotoxicity of dietary Cr through blocking Cr^III cellular accumulation.     

Sensitive detection of human breast cancer cells based on aptamer–cell–aptamer sandwich architecture

Breast cancer is one of the most critical threats to the health of women, and the development of new methods for early diagnosis is urgently required, so this paper reports a method to detect Michigan cancer foundation-7 (MCF-7) human breast cancer cells with considerable sensitivity and selectivity by using electrochemical technique. In this method, a mucin 1 (MUC1)-binding aptamer is adopted to recognize MCF-7 human breast cancer cells, while enzyme labeling is employed to produce amplified catalytic signals. The molecular recognition and the signal amplification are elaborately integrated by fabricating an aptamer–cell–aptamer sandwich architecture on an electrode surface, thus a biosensor for the detection of MCF-7 is fabricated based on the architecture. The detection range can be from 100 to 1 × 10⁷ cells, and the detection limit can be as low as 100 cells. The method is also cost-effective and conveniently operated, implying potential help for the development of early diagnosis of breast cancer.     

Fluorescent taxoids

Background: Taxol^* is a natural product produced by the Pacific Yew, Taxus brevifolia, that has emerged as a prominent chemotherapeutic agent for the treatment of solid tumors. Taxol's biochemical mode of action has been well studied: it binds to microtubules, stabilizing them and preventing their depolymerization to tubulin subunits. At lower dosage levels, taxol also interferes with the normal dynamics of the tubulin—microtubule equilibrium. This biochemical effect causes taxol's ultimate physiological effect, cell cycle arrest; taxol is thought to block anaphase A of mitosis. Taxol also causes a number of intriguing secondary effects on interphase cells that are poorly understood. We believed that a bio-active fluorescent taxol derivative could be a useful tool in the study of these cellular mechanisms, especially in interphase cells.Results: We have synthesized and characterized a series of stable, fluorescently labeled derivatives of taxol that bind to microtubules and have cytotoxicities similar to that of taxol. Fluorescence microscopy experiments in interphase human foreskin fibroblast (HFF) cells indicate that one of these, a sulforhodamine taxoid, is particularly well suited for optical microscopy. The use of this taxoid in HFF cells revealed a previously undetected localization of taxoids to the nucleolus during interphase.Conclusion: The production of a new fluorescent derivative of taxol provides a useful tool, enabling cellular biologists to study taxol's mechanism of action. It is hoped that this material will prove particularly useful for the study of taxol's effects upon interphase cells.