Synthesis and Primary Activity Assay of Novel Benitrobenrazide and Benserazide Derivatives.

Schiff bases attract research interest due to their applications in chemical synthesis and medicinal chemistry. In recent years, benitrobenrazide and benserazide containing imine moiety have been synthesized and characterized as promising inhibitors of hexokinase 2 (HK2), an enzyme overexpressed in most cancer cells. Benserazide and benitrobenrazide possess a common structural fragment, a 2,3,4-trihydroxybenzaldehyde moiety connected through a hydrazone or hydrazine linker acylated on an N' nitrogen atom by serine or a 4-nitrobenzoic acid fragment. To avoid the presence of a toxicophoric nitro group in the benitrobenrazide molecule, we introduced common pharmacophores such as 4-fluorophenyl or 4-aminophenyl substituents. Modification of benserazide requires the introduction of other endogenous amino acids instead of serine. Herein, we report the synthesis of benitrobenrazide and benserazide analogues and preliminary results of inhibitory activity against HK2 evoked by these structural changes. The derivatives contain a fluorine atom or amino group instead of a nitro group in BNB and exhibit the most potent inhibitory effects against HK2 at a concentration of 1 µM, with HK2 inhibition rates of 60% and 54%, respectively.

Synthesis and in vitro cytotoxic activity of dye-linker-macrocycle conjugates with variable linker length and components.

The study investigated the structure-activity relationship of newly synthesized dye-linker-macrocycle (DLM) conjugates and the effect of each component on various biological properties, including cytotoxicity, cellular uptake, intracellular localization, interaction with DNA and photodynamic effects. The conjugates were synthesized by combining 1,8-naphthalimide and thioxanthone dyes with 1,4,7,10-tetraazacyclododecane (cyclen) and 1-aza-12-crown-4 (1A12C4) using alkyl linkers of different lengths. The results revealed significant differences in biological activity among the various series of conjugates. Particularly, 1A12C4 conjugates exhibited notably higher cytotoxicity compared to cyclen conjugates. Conjugation with 1A12C4 proved to be an effective strategy for increasing cellular uptake and cytotoxicity of small-molecule conjugates. In addition, the results highlighted the critical role of linker length in modulating the biological activity of DLM conjugates. It became clear that the choice of each component (dye, macrocycle and linker) could significantly alter the biological activity of the conjugates.

Glycoconjugates of Mucochloric Acid-Synthesis and Biological Activity.

The pharmacological effects of the presence of a sugar moiety, 1,2,3-triazole ring and silyl groups in the structure of biologically active compounds have been extensively studied in drug design and medicinal chemistry. These components can be useful tools to tailoring the bioavailability of target molecules. Herein we present the study on the impact of the sugar substituent structure and triisopropylsilyl group presence on the anticancer activity of mucochloric acid (MCA) derivatives containing the furan-2(5H)-one or 2H-pyrrol-2-one core. The obtained results clearly indicated that tested compounds caused a significant decrease in cell viability of HCT116 and MCF-7 cell lines. MCF-7 cells indicate serious resistance toward investigated compounds in comparison with HCT116 cell line, it suggests that estrogen-dependent breast cancer cells are significantly less sensitive to the tested derivatives. Depending on the structure of the sugar, the type and site of connection with the furanone or 2H-pyrrol-2-one derivative and the presence of the silyl group, the selectivity of the compound towards cancer cells can be controlled. The obtained results may have an impact on the design of new furanone-based anticancer compounds.

The relationships between selected serum adipokines and thyroid function in patients with obesity.

INTRODUCTION: The study was designed to evaluate the effect of thyroid function on serum levels of different adipokines in obesity. We investigated relationships between the thyroid axis and serum levels of leptin, adiponectin, and chemerin, and we assessed the influence of autoimmune thyroiditis (AIT) on those relations. MATERIAL AND METHODS: The participants of this study included 181 euthyroid patients (147 women and 34 men) with obesity [body mass index (BMI) 30-39.9 kg/m²] and severe (morbid) obesity (BMI ≥ 40 kg/m²), aged 18 to 65 years. We divided all obese patients by thyrotropic hormone (TSH) tertiles, and we compared all participants according to BMI. Patients were further divided into the following subgroups: with chronic autoimmune thyroiditis and without autoimmune thyroiditis. RESULTS: Comparison of obese patients according to TSH tertile showed significantly higher serum concentrations of leptin, chemerin, and thyroid antibodies and an increased leptin/adiponectin ratio in the group with high normal TSH. We observed statistically significant correlations between serum TSH and BMI, leptin, chemerin, thyroid peroxidase antibodies, and the leptin/adiponectin ratio. In patients diagnosed with autoimmune thyroiditis, higher levels of antibodies and TSH were found, but there were no differences in homeostatic model assessment index (HOMA-I), the leptin/adiponectin ratio, and adipokine levels. In obese patients the relationships between serum leptin, chemerin, the leptin/adiponectin ratio, and BMI were dependent on each other. CONCLUSION: Serum leptin, chemerin, the leptin/adiponectin ratio, and BMI are significantly higher in patients with high normal TSH; however, selected adipokines are not related to the presence of autoimmune thyroiditis. There are interplays between TSH, adipokines, and obesity, but how these relationships are related remains unknown.

Hexokinase 2 Inhibition and Biological Effects of BNBZ and Its Derivatives: The Influence of the Number and Arrangement of Hydroxyl Groups.

Hexokinase 2 (HK2), an enzyme of the sugar kinase family, plays a dual role in glucose metabolism and mediating cancer cell apoptosis, making it an attractive target for cancer therapy. While positive HK2 expression usually promotes cancer cells survival, silencing or inhibiting this enzyme has been found to improve the effectiveness of anti-cancer drugs and even result in cancer cell death. Previously, benitrobenrazide (BNBZ) was characterized as a potent HK2 inhibitor with good anti-cancer activity in mice, but the effect of its trihydroxy moiety (pyrogallol-like) on inhibitory activity and some cellular functions has not been fully understood. Therefore, the main goal of this study was to obtain the parent BNBZ (2a) and its three dihydroxy derivatives 2b-2d and to conduct additional physicochemical and biological investigations. The research hypothesis assumed that the HK2 inhibitory activity of the tested compounds depends on the number and location of hydroxyl groups in their chemical structure. Among many studies, the binding affinity to HK2 was determined and two human liver cancer cell lines, HepG2 and HUH7, were used and exposed to chemicals at various times: 24 h, 48 h and 72 h. The study showed that the modifications to the structures of the new BNBZ derivatives led to significant changes in their activities. It was also found that these compounds tend to aggregate and exhibit toxic effects. They were found to contribute to: (a) DNA damage, (b) increased ROS production, and (c) disruption of cell cycle progression. It was observed that, HepG2, occurred much more sensitive to the tested chemicals than the HUH7 cells; However, regardless of the used cell line it seems that the increase in the expression of HK2 in cancer cells compared to normal cells which have HK2 at a very low level, is a serious obstacle in anti-cancer therapy and efforts to find the effective inhibitors of this enzyme should be intensified.

Synthesis and Preliminary Anticancer Activity Assessment of N-Glycosides of 2-Amino-1,3,4-thiadiazoles.

The addition of 2-amino-1,3,4-thiadiazole derivatives with parallel iodination of differently protected glycals has been achieved using a double molar excess of molecular iodine under mild conditions. The corresponding thiadiazole derivatives of N-glycosides were obtained in good yields and anomeric selectivity. The usage of iodine as a catalyst makes this method easy, inexpensive, and successfully useable in reactions with sugars. Thiadiazole derivatives were tested in a panel of three tumor cell lines, MCF-7, HCT116, and HeLa. These compounds initiated biological response in investigated tumor models in a different rate. The MCF-7 is resistant to the tested compounds, and the cytometry assay indicated low increase in cell numbers in the sub- G1 phase. The most sensitive are HCT-116 and HeLa cells. The thiadiazole derivatives have a pro-apoptotic effect on HCT-116 cells. In the case of the HeLa cells, an increase in the number of cells in the sub-G1- phase and the induction of apoptosis was observed.

Effect of Selected Silyl Groups on the Anticancer Activity of 3,4-Dibromo-5-Hydroxy-Furan-2(5H)-One Derivatives.

The pharmacological effects of carbon to silicon bioisosteric replacements have been widely explored in drug design and medicinal chemistry. Here, we present a systematic investigation of the impact of different silyl groups on the anticancer activity of mucobromic acid (MBA) bearing furan-2(5H)-one core. We describe a comprehensive characterization of obtained compounds with respect to their anticancer potency and selectivity towards cancer cells. All four novel compounds exert stronger antiproliferative activity than MBA. Moreover, 3b induce apoptosis in colon cancer cell lines. A detailed investigation of the mechanism of action revealed that 3b activity stems from the down-regulation of survivin and the activation of caspase-3. Furthermore, compound 3b attenuates the clonogenic potential of HCT-116 cells. Interestingly, we also found that depending on the type of the silyl group, compound selectivity towards cancer cells could be precisely controlled. Collectively, we demonstrated the utility of silyl groups for adjusting both the potency and selectivity of silicon-containing compounds. These data reveal a link between the types of silyl group and compound potency, which could have bearings for the design of novel silicon-based anticancer drugs.

Obesity and Thyroid Axis.

Development of obesity is primarily the result of imbalance between energy intake and energy expenditure. Thyroid hormones influence energy expenditure by regulating cellular respiration and thermogenesis and by determining resting metabolic rate. Triiodothyronine influences lipid turnover in adipocytes and impacts appetite regulation through the central nervous system, mainly the hypothalamus. Thyroid-stimulating hormone may also influence thermogenesis, suppress appetite and regulate lipid storage through lipolysis and lipogenesis control. Subclinical hypothyroidism may induce changes in basal metabolic rate with subsequent increase in BMI, but obesity can also affect thyroid function via several mechanisms such as lipotoxicity and changes in adipokines and inflammatory cytokine secretion. The present study investigated the complex and mutual relationships between the thyroid axis and adiposity.

Polyamine-Oligonucleotide Conjugates: 2'-OMe-Triazole-Linked 1,4,7,10-Tetraazacyclododecane and Intercalating Dyes and Their Effect on the Thermal Stability of DNA Duplexes.

Oligonucleotides with the sequences 5'-GTG AUPA TGC, 5'-GCA TAUP CAC and 5'-GUPG ATA UPGC, where UP is 2'-O-propargyl uridine, were subjected to post-synthetic Cu(I)-catalyzed azide-alkyne cycloaddition to attach 1,4,7,10-tetraazacyclododecane (cyclen) and two well-known DNA intercalating dyes: thioxanthone and 1,8-naphthalimide. We propose a convenient cyclen protection-deprotection strategy that allows efficient separation of the resulting polyamine-oligonucleotide conjugates from the starting materials by RP-HPLC to obtain high-purity products. In this paper, we present hitherto unknown macrocyclic polyamine-oligonucleotide conjugates and their hybridization properties reflected in the thermal stability of thirty-two DNA duplexes containing combinations of labeled strands, their unmodified complementary strands, and strands with single base pair mismatches. Circular dichroism measurements showed that the B-conformation is retained for all dsDNAs consisting of unmodified and modified oligonucleotides. An additive and destabilizing effect of cyclen moieties attached to dsDNAs was observed. Tm measurements indicate that placing the hydrophobic dye opposite to the cyclen moiety can reduce its destabilizing effect and increase the thermal stability of the duplex. Interestingly, the cyclen-modified U showed significant selectivity for TT mismatch, which resulted in stabilization of the duplex. We conclude the paper with a brief review and discussion in which we compare our results with several examples of oligonucleotides labeled with polyamines at internal strand positions known in the literature.

Carbazole modified oligonucleotides: synthesis, hybridization studies and fluorescence properties.

Synthesis of the novel thiophenyl carbazole phosphoramidite DNA building block 5 was accomplished in four steps using a Suzuki-Miyaura cross-coupling reaction from the core carbazole and it was seamlessly accommodated into a 9-mer DNA-based oligonucleotide by incorporation at the flanking 5'-end in combination with a central insertion of an LNA-T nucleotide. The carbazole-containing oligonucleotide was combined in different duplex hybrids, which were characterized by thermal denaturation, circular dichroism and fluorescence studies. The carbazole monomer modulates the duplex stability in various ways. Thus, monomer Z increased the thermal stability of the 9-mer towards the complementary 9-mer/15-mer DNA duplex by 4.2 °C. Furthermore, indications of its intercalation into the duplex were obtained by modeling studies and robust decreases in fluorescence emission intensities upon duplex formation. In contrast, no clear intercalating tendency was corroborated for monomer Z within the DNA/RNA hybrid duplex as indicated by moderate quenching of the fluorescence and similar duplex thermal stabilities relative to the corresponding control duplex. The recognition efficiencies of the carbazole modified oligonucleotide toward single nucleotide mismatches were studied with two 15-mer model targets (DNA and RNA). For both systems, mismatches positioned at the juxtaposition of the carbazole monomer showed pronounced deceases in thermal denaturation temperature. Steady-state fluorescence emission studies of all mismatched duplexes with incorporation of Z monomer typically displayed efficient fluorescence quenching.

The Synthesis of α-Aminophosphonates via Enantioselective Organocatalytic Reaction of 1-(N-Acylamino)alkylphosphonium Salts with Dimethyl Phosphite.

α-Aminophosphonic acids are phosphorus analogues of α-amino acids. Compounds of this type find numerous applications in medicine and crop protection due to their unique biological activities. A crucial factor in these activities is the configuration of the stereoisomers. Only a few methods of stereoselective transformation of α-amino acids into their phosphorus analogues are known so far and all of them are based on asymmetric induction, thus involving the use of a chiral substrate. In contrast, we have focused our efforts on the development of an effective method for this type of transformation using a racemic mixture of starting N-protected α-amino acids and a chiral catalyst. Herein, a simple and efficient stereoselective organocatalytic α-amidoalkylation of dimethyl phosphite by 1-(N-acylamino)alkyltriphenylphosphonium salts to enantiomerically enriched α-aminophosphonates is reported. Using 5 mol% of chiral quinine- or hydroquinine-derived quaternary ammonium salts provides final products in very good yields up to 98% and with up to 92% ee. The starting phosphonium salts were easily obtained from α-amino acid derivatives by decarboxylative methoxylation and subsequent substitution with triphenylphosphonium tetrafluoroborate. The appropriate self-disproportionation of enantiomers (SDE) test for selected α-aminophosphonate derivatives via achiral flash chromatography was performed to confirm the reliability of the enantioselectivity results that were obtained.

Selected nucleos(t)ide-based prescribed drugs and their multi-target activity.

Nucleos(t)ide analogues play pivotal roles as antiviral, cytotoxic or immunosuppressive agents. Here, we review recent reports of nucleoside analogues that exhibit broad-spectrum activity towards multiple life-threatening RNA and DNA viruses. We also present a discussion about nucleoside antimetabolites-approved antineoplastic agents-that have recently been shown to have antiviral and/or antibacterial activity. The approved drugs and drug combinations, as well as recently identified candidates for investigation and/or experimentation, are discussed. Several examples of repurposed drugs that have already been approved for use are presented. This strategy can be crucial for the first-line treatment of acute infections or coinfections and for the management of drug-resistant strains.

Michaelis-Arbuzov-Type Reaction of 1-Imidoalkyltriarylphosphonium Salts with Selected Phosphorus Nucleophiles.

In this study, Michaelis-Arbuzov-type reaction of 1-imidoalkyltriarylphosphonium salts with phosphites, phosphonites, and phosphinites was used in the synthesis of a wide range of phosphorus analogs of α-amino acids such as 1-imidoalkylphosphonates, 1-imidoalkylphosphinates, and 1-imidoalkylphosphine oxides. Large differences were observed in the reactivity of substrates depending on their structure, especially on the type of phosphonium moiety and N-protecting group. The conditions under which the expected products can be obtained in good to excellent yields have been developed. Mechanistic aspects of the transformation have been provided.

Copper(II)-Catalyzed Iodinations of Carbazoles: Access to Functionalized Carbazoles.

A copper-catalyzed iodination of carbazoles has been developed. Barluenga's reagent IPy2BF4 is used to generate a soft electrophilic halonium species for the iodination of the carbazoles. This report represents the first concept of copper-catalyst-promoted electrophilic halogenation of carbazoles. We demonstrated numerous applications of this methodology synthesizing diverse carbazole derivatives, i.e., both electron-rich and electron-deficient systems.

Anticancer Activity and Topoisomerase II Inhibition of Naphthalimides with ω-Hydroxylalkylamine Side-Chains of Different Lengths.

BACKGROUND: The substituted 1,8-Naphthalimides (1H-benzo[de]isoquinoline-1,3(2H)- diones) are known as DNA intercalators stabilizing DNA-Topoisomerase II complexes. This interaction disrupts the cleavage-relegation equilibrium of Topo II, resulting in formation of broken strands of DNA. OBJECTIVE: To investigate the influence of type of substituents and substitution positions in 1,8- naphthalimde skeleton on the inhibition of Topoisomerase II activity. METHODS: The starting 1,8-naphthalimide were prepared from acenaphthene by introduction of appropriate substituents followed by condensation with ω-hydroxylakylamines of different chain length. The substituents were introduced to 1,8-naphthalimide molecule by nucleophilic substitution of leaving groups like nitro or bromo present in 4 or 4,5- positions using the ω- hydroxylalkylamines. The bioactivity of obtained compounds was examined in model cell lines. RESULTS: Antiproliferative activity of selected compounds against HCT 116 human colon cancer cells, human non-small cell lung cells A549 and non-tumorigenic BEAS-2B human bronchial epithelium cells was examined. Several of investigated compounds exhibit a significant activity (IC50 µM to 7 µM) against model cancer cell lines. It was demonstrated that upon treatment with concentration of 200 µM, all derivatives display Topo II inhibitory activity, which may be compared with activity of Amonafide. CONCLUSION: The replacement of the nitro groups in the chromophore slightly reduces its anticancer activities, whereas the presence of both nitro group and ω-hydroxylalkylamine chain resulted in seriously increased anticancer activity. Obtained compounds showed Topo II inhibitory activity, moreover, influence of the substitution pattern on the ability to inhibit Topo II activity and cancer cells proliferation was observed.

l,8-Naphthalimide based DNA intercalators and anticancer agents. A systematic review from 2007 to 2017.

In this review, we describe a detailed investigation about the structural variations and relative activity of 1,8-naphthalimide based intercalators and anticancer agents. The 1,8-naphthalimides binds to the DNA via intercalation, and exert their antitumor activities through Topoisomerase I/II inhibition, photoinduced DNA damage or related mechanism. Here, our discussion focused on works published over the last ten years (2007-2017) related to therapeutic applications, in the order of cancer treatment followed by other properties of 1,8-naphthalimides. In preparing for this review, we considered that several seminal reviews have appeared over the last fifteen years and focused on closely related subjects, however, none of them is exhaustive.

1-(N-Acylamino)alkyltriarylphosphonium Salts with Weakened Cα-P⁺ Bond Strength-Synthetic Applications.

The α-amidoalkylating properties of 1-(N-acylamino)alkyltriarylphosphonium salts with weakened Cα-P⁺ bond strength are discussed and examined. It is demonstrated that such type of phosphonium salts reacts smoothly with a diverse array of carbon- and heteroatom-based nucleophiles, including 1-morpholinocyclohexene, 1,3-dicarbonyl compounds, benzotriazole sodium salt, p-toluenesulfinate sodium salt, benzylamine, triarylphosphines, and other P-nucleophiles. Reactions are conducted at room temperature, in a short time (5⁻15 min) and mostly without catalysts. Simple work-up procedures result in good or very good yields of products. The structures of known compounds were established by spectroscopic methods and all new compounds have been fully characterized using ¹H-, 13C-, 31P-NMR, IR spectroscopy, and high-resolution mass spectrometry. Mechanistic aspects of described transformations are also performed and discussed. It was demonstrated that unique properties make 1-(N-acylamino)alkyl-triarylphosphonium salts with weakened Cα-P⁺ bond strength interesting building blocks with great potential, especially in α-amidoalkylation reactions.

Simple 2(5H)-furanone derivatives with selective cytotoxicity towards non-small cell lung cancer cell line A549 - Synthesis, structure-activity relationship and biological evaluation.

A series of 5-alkoxy derivatives of 3,4-dichloro-5-hydroxyfuran-2-(5H)-one (mucochloric acid, MCA) were obtained and subsequently subjected to modification in the C-4 position of 2(5H)-furanone ring. The cytotoxicity of newly synthesized compounds was evaluated in MTT assay against non-small cell lung cancer (A549) and healthy lung epithelial cell line (BEAS-2B). The derivatives containing a branched alkoxy substituent in the C-5 position demonstrated the highest anticancer properties, whereas modification of compounds in the C-4 position of 2(5H)-furanone ring only slightly improve their antiproliferative properties. Compounds 12 and 15 exhibited the best selectivity towards A549 cells and were also evaluated in a panel of cancer cell lines of different origin. Further investigation revealed that treatment of A549 cell line with compounds 12 and 15 led to G2 phase cell cycle arrest and induction of caspase-independent cell death. Moreover, compound 12 was found to act synergistically with erlotinib.

The Effect of Aromatic Diimide Side Groups on the π-Conjugated Polymer Properties.

The presented study describes the method for the synthesis and characterization of a new class of conjugated copolymers containing a perylenediimide (PDI) and naphthalene diimide (NDI) side groups. The main conjugated backbone is a donor-acceptor polymer poly[3,6-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] containing thiophene and carbazole as donor units and benzothiadiazole as an acceptor unit. The presented compounds were synthesized in a multistep synthesis. The polymerization was carried out by Suzuki or Stille coupling reaction. Redox properties of the studied polymers were tested in different conditions. Electrochemical investigation revealed independent reduction of the main polymer chain and diimide side groups. UV-Vis spectroscopy revealed the overlap of two absorption spectra. The difference between the electron affinity of the polymer main chain and that of the diimides estimated electrochemically is approximately 0.3 eV.

Evaluation of biological properties of 3,3',4,4'-benzophenonetetracarboxylic dianhydride derivatives and their ability to inhibit hexokinase activity.

This investigation has explored the properties of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BDTA) derivatives with regard to their being prospective inhibitors of hexokinase II (HKII). A pluripotent embryonic carcinoma cell line P19 (ECC), was used as the biological target for newly generated potential inhibitors of HKII. The results obtained from Virtual High-Throughput Screening (VHTS), molecular modeling and biological activity studies showed BDTA to be a promising leading structure with a good binding score and simplest functionalization. The inhibitory effect was measured after 72h incubation. Of selected BDTA derivatives, the most active was compound 3b, containing 3-hydroxyphenyl moiety in the para position, being able at 100µM to decrease the mass of differentiated P19dCs cells by 30%, changing both the mitochondrial transmembrane potential and reactive oxygen species level. Under these conditions, only compound 3b had the ability to decrease hexokinase activity in a dose-dependent manner.