Pentamethinium Salts Nanocomposite for Electrochemical Detection of Heparin.

This study presents a simple route to heparin detection and develops a voltammetric approach using supramolecular principles and nanomaterials. Nanocomposites, including gold nanoparticles (AuNPs) and γ-substituted pentamethinium salts (PMS) deposited on a glass carbon (GC) electrode surface (GC/AuNPs/PMS) and covered by a plasticized poly(vinyl chloride) (PVC) membrane, are proposed for heparin detection. The conductivity of the nonconducting PVC-plasticized membrane is guaranteed by AuNPs, and the selectivity is provided by the interaction between γ-substituted PMS and anionic analytes. In order to extend the linear range, it is necessary to apply a solvent compatible with PVC-plasticized membrane, namely tetrahydrofuran. The proposed voltammetric sensor showed a concentration dependence from 1.72 up to 45.02 IU mL-1 heparin and was used for heparin detection in saline and biological samples with recovery of 95.1-100.9%.

Anticancer pentamethinium salt is a potent photosensitizer inducing mitochondrial disintegration and apoptosis upon red light illumination.

Despite progress in the development and application of novel therapeutic agents, cancer remains a major cause of death worldwide. Therefore, there is a need for new approaches to increase therapeutic options and efficiency. The metabolism of cancer cells differs from that of non-malignant cells and their mitochondria show altered activities that can be utilized as a target for drug development. Salt 1 is a low-molecular weight heterocyclic compound of the polymethine class that accumulates in the mitochondria of cancer cells and selectively disrupts their metabolism. Salt 1 leads to a non-apoptotic form of cell death in vitro that is associated with an autophagic cellular response and eventual metabolic collapse, and inhibits human tumor xenograft growth in vivo without apparent toxicity for normal cells. As a pentamethinium compound, salt 1 exhibits intrinsic fluorescence and is a candidate for photosensitization after excitation by appropriate wavelengths of light. Herein, we report that salt 1 is a potent photosensitizer, which generates a photodynamic effect and provides enhanced cytotoxicity compared to salt 1 without light exposure. Importantly, photosensitization is optimally induced by red light, which is used clinically for photosensitization and penetrates further into tissues than lower wavelengths. Cancer cells treated with non-cytotoxic doses of salt 1 and subsequently exposed to 630 nm light show severely damaged mitochondria, manifested by reduced mitochondrial membrane potential and disintegration of the mitochondrial tubular network. As a consequence, cancer cells lose their proliferative potential and die via apoptosis in the presence of light. These findings indicate that salt 1 is a promising photosensitizer with potential to be combined with 630 nm light to strengthen its efficacy in cancer therapy.

Coumarin Tröger's base derivatives with cyanine substitution as selective and sensitive fluorescent lysosomal probes.

The fluorescent probes based on Tröger's base motive with both coumarin and cyanine substitution 11-13 have been synthesized by multi-step synthesis in high overall yields. Intracellular localization of prepared probes have been tested using four different cell lines (HF-P4, BLM, U-2 OS and A-2058). Prepared probes have intensive green and red fluorescence. Co-localization with commercial lysosome specific marker LysoTracker Blue DND 22 has been confirmed that all prepared fluorescent probes labeled lysosomal compartment with high selectivity and probes show excellent brightness at low concentration.

A Cyclic Pentamethinium Salt Induces Cancer Cell Cytotoxicity through Mitochondrial Disintegration and Metabolic Collapse.

Cancer cells preferentially utilize glycolysis for ATP production even in aerobic conditions (the Warburg effect) and adapt mitochondrial processes to their specific needs. Recent studies indicate that altered mitochondrial activities in cancer represent an actionable target for therapy. We previously showed that salt 1-3C, a quinoxaline unit (with cytotoxic activity) incorporated into a meso-substituted pentamethinium salt (with mitochondrial selectivity and fluorescence properties), displayed potent cytotoxic effects in vitro and in vivo, without significant toxic effects to normal tissues. Here, we investigated the cytotoxic mechanism of salt 1-3C compared to its analogue, salt 1-8C, with an extended side carbon chain. Live cell imaging demonstrated that salt 1-3C, but not 1-8C, is rapidly incorporated into mitochondria, correlating with increased cytotoxicity of salt 1-3C. The accumulation in mitochondria led to their fragmentation and loss of function, accompanied by increased autophagy/mitophagy. Salt 1-3C preferentially activated AMP-activated kinase and inhibited mammalian target of rapamycin (mTOR) signaling pathways, sensors of cellular metabolism, but did not induce apoptosis. These data indicate that salt 1-3C cytotoxicity involves mitochondrial perturbation and disintegration, and such compounds are promising candidates for targeting mitochondria as a weak spot of cancer.

Versatile fluorophores for bioimaging applications: π-expanded naphthalimide derivatives with skeletal and appendage diversity.

Four novel fluorescent cores bearing a transformable functional group based on a π-expanded naphthalimide including a fused pyranone or furan ring have been prepared. Fluorescent probes LysoSers 13-16 for lysosomal targeting have been tested. Co-localization with a commercial lysosome specific marker confirmed that the LysoSers labeled the lysosomal compartment with high selectivity. The LysoSers show excellent brightness and low toxicity.

Pentamethinium salts as ligands for cancer: Sulfated polysaccharide co-receptors as possible therapeutic target.

A series of pentamethinium salts with benzothiazolium and indolium side units comprising one or two positive charges were designed and synthesized to determine the relationships among the molecular structure, charge density, affinity to sulfated polysaccharides, and biological activity. Firstly, it was found that the affinity of the pentamethinium salts to sulfated polysaccharides correlated with their biological activity. Secondly, the side heteroaromates displayed a strong effect on the cytotoxicity and selectivity towards cancer cells. Finally, doubly charged pentamethinium salts possessing benzothiazolium side units exhibited remarkably high efficacy against a taxol-resistant cancer cell line.

Metallomics for Alzheimer's disease treatment: Use of new generation of chelators combining metal-cation binding and transport properties.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder affecting tens of million people. Currently marketed drugs have limited therapeutic efficacy and only slowing down the neurodegenerative process. Interestingly, it has been suggested that biometal cations in the amyloid beta (Aß) aggregate deposits contribute to neurotoxicity and degenerative changes in AD. Thus, chelation therapy could represent novel mode of therapeutic intervention. Here we describe the features of chelators with therapeutically relevant mechanism of action. We have found that the tested compounds effectively reduce the toxicity of exogenous Aß and suppress its endogenous production as well as decrease oxidative stress. Cholyl hydrazones were found to be the most active compounds. In summary, our data show that cation complexation, together with improving transport efficacy may represent basis for eventual treatment strategy in AD.

Optical probes and sensors as perspective tools in epigenetics.

Modifications of DNA cytosine bases and histone posttranslational modifications play key roles in the control of gene expression and specification of cell states. Such modifications affect many important biological processes and changes to these important regulation mechanisms can initiate or significantly contribute to the development of many serious pathological states. Therefore, recognition and determination of chromatin modifications is an important goal in basic and clinical research. Two of the most promising tools for this purpose are optical probes and sensors, especially colourimetric and fluorescence devices. The use of optical probes and sensors is simple, without highly expensive instrumentation, and with excellent sensitivity and specificity for target structural motifs. Accordingly, the application of various probes and sensors in the recognition and determination of cytosine modifications and structure of histones and histone posttranslational modifications, are discussed in detail in this review.

New method for recognition of sterol signalling molecules: methinium salts as receptors for sulphated steroids.

In this work, we studied indolium and benzothiazolium pentamethine salts 1-3 as novel type of receptors for the recognition of sulphated signalling molecules (sulphated steroids: oestrone, pregnenolone and cholesterol sulphate). A recognition study was performed in an aqueous medium (1mM phosphate buffer (H2O:MeOH; 99:1 (v/v))) at pH 7.34. The tested salts displayed a high affinity for these sulphated analytes, mainly for cholesterol sulphate. However, no interaction between the salts and control, non-sulphated sterol analytes (cholesterol and bile acid) was observed. The highest affinity for the sulphated steroids was observed for benzothiazole salt 1. This salt also displayed different spectral behaviour from that observed for carbocyanine salts 2 and 3. In this presence of cholesterol sulphate, benzothiazole salt 1 displayed significant spectral changes depending on the medium used: a blue shift in the aqueous medium and a red shift in the methanolic one (H2O:MeOH; 2:1 (v/v)). Subsequently preliminary in vivo study showed that, salt 1 significantly inhibits a growth of breast carcinoma on Nu/nu mice model.

Rational design of chemical ligands for selective mitochondrial targeting.

The rational design of molecules with selective intracellular targeting is a great challenge for contemporary chemistry and life sciences. Here, we demonstrate a rational approach to development of compartment-specific fluorescent dyes from the γ-aryl substituted pentamethine family. These novel dyes exhibit an extraordinary affinity and selectivity for cardiolipin in inner mitochondrial membrane and possess excellent photostability, fluorescent properties, and low phototoxicity. Selective imaging of live and fixed mitochondria was achieved in various cell lines using nanomolar concentrations of these dyes. Their high localization specificity and low toxicity enables study of morphological changes, structural complexity, and dynamics of mitochondria playing a pivotal role in many pathological diseases. These far-red emitting dyes could also serve in a variety of biomedical applications.

Combination of two chromophores: synthesis and PDT application of porphyrin-pentamethinium conjugate.

A general method for the synthesis of a novel porphyrin with pentamethine periphery substitution is described. The combination of two chromophoric systems, a porphyrin macrocycle and a polymethine moiety was achieved by transformation of tetrapyridyl porphyrin. The synthetic strategy included conversion of the tetrapyridyl porphyrin to its corresponding 2,4-dinitrophenylpyridinuim salt, which was subsequently converted to tetrakis(meso-pentamethinium salt) on the porphyrin core. This novel porphyrin exhibited PDT properties as manifested by the induction of apoptosis in the myeloid cell line HL-60 and the effective reduction of amelanotic melanoma in nude mice.

Coordination conjugates of therapeutic proteins with drug carriers: a new approach for versatile advanced drug delivery.

We present here a general system for the coordination attachment of therapeutic proteins to a drug delivery system and its application in combined therapy. Proof of concept is demonstrated by the synthesis and testing of the targeted drug delivery system for cytostatics, which is based on a combination of the drug carrier Zn-porphyrin-cyclodextrin conjugates and their supramolecular coordination complexes with immunoglobulins. This system can be as readily used for a variety of therapeutic and targeting proteins including PAs, MAs, lectins, and HSA. Moreover, it allows combined photodynamic therapy, cell targeted chemotherapy and immunotherapy. When tested in a mouse model with human C32 carcinoma, the therapeutic superiority of the coordination assembly nanosystem was shown in comparison with the efficacy of building blocks used for the construction of the system.

Selective recognition of a saccharide-type tumor marker with natural and synthetic ligands: a new trend in cancer diagnosis.

It is well known that saccharides and their glycoconjugates can have an important influence on various serious pathologic stages such as cancer. They can regulate tumor proliferation, invasion, hematogenous metastasis, and angiogenesis. These facts clearly show the importance of cancer saccharide recognition. In medicine, sensor analysis is one of the best methods for recognition and determination of biologically important analytes. The development and study of sensors for saccharide tumor markers can open a new way for their detection. Therefore, this review is focused on recognition of saccharide-based cancer markers by natural or synthetic selective ligands working as bio- and chemosensors. The design and application of these ligands for cancer diagnosis is a useful direction of research. Moreover, it also opens the possibility of using these agents for the targeted drug transport required for advanced anticancer therapy.

Porphyrin-cyclodextrin conjugates as a nanosystem for versatile drug delivery and multimodal cancer therapy.

The porphyrin-cyclodextrin conjugates were prepared and tested for selective and effective multifunctional drug delivery and therapy. The porphyrin receptor system combines efficient binding of the selected drug to the cyclodextrin cavity and photosensitizing properties of the porphyrin moiety with high accumulation of the whole complex in cancer tissue. The combined effect of chemotherapy and photodynamic therapy is demonstrated by in vitro and in vivo studies.

Glycol porphyrin derivatives as potent photodynamic inducers of apoptosis in tumor cells.

The design and synthesis of glycol-functionalized porphyrins that contain one to four low molecular weight glycol chains that are linked via ether bonds to the meta-phenyl positions of meso-tetraphenylporphyrin and the comparison of fluorinated and nonfluorinated para derivatives are reported. The cellular uptake and photodynamic activity significantly depend on terminal groups of the glycol substituent. Hydroxy glycol porphyrins, in contrast with methoxy glycol porphyrins, show efficient intracellular transport and a high induction of apoptosis in tumor cell lines in vitro . Furthermore, the ethylene glycol chain at the meta position exhibits a superior efficacy that leads to the permanent ablation of human breast carcinoma (MDA-MB-231) in nude mice. In addition, fluorination enhanced the photosensitizing potential of para-phenyl derivatives. The analysis of the cell-death mechanism revealed that glycol-functionalized porphyrins represent novel nonmitochondrially localized photosensitizers that have a profound ability to induce apoptosis in tumor cells that act upstream of caspase activation. The strong interaction with a tumor marker (sialic acid) indicates the preferential association of these compounds with tumor cells.

Optical sensing of sulfate by polymethinium salt receptors: colorimetric sensor for heparin.

Polymethinium salts based on substituted malondialdehyde have been prepared; the salt with PEG substitution showed high selectivity for sulfate anions and heparin in aqueous medium at physiological condition; intracellular imaging of heparin-rich subcellular compartments was achieved with our polymethinium novel receptor for cancer cell lines.

1H,13C, 19F NMR, and ESI mass spectral characterization of two geminal difluorosteroids.

Two geminal difluorosteroids, 3,3-difluoro-5beta-cholan-24-oic acid (1) and 3,3-difluoro-5alpha-androstan-17-one (2), have been prepared from corresponding ketosteroids with diethylaminosulphurtrifluoride (DAST) treatment in moderate yields. The structures of 1 and 2 have been characterized by (1)H, (13)C, (19)F NMR, and ESI mass spectral techniques.

Chromophoric binaphthyl derivatives.

A short synthetic route is outlined, starting from bromo-BN derivatives, via halogen lithium exchange, subsequent Michael reaction with dimethylaminoacrolein, hydrolysis to the corresponding aldehyde, and final condensation with a benzothiazolium unit to produce a BN-pentamethinium system, which absorbs in the visible range around 450 nm. Enantiopure ligands show a decent Cotton effect in the CD spectrum. Preliminary data show potential of these compounds in the area of supramolecular chemistry (enantioselective recognition) and also for medicinal application (induction of apoptosis). [reaction: see text]