Combination therapy is rarely used to counter the evolution of resistance in bacterial infections. Expansion of the use of combination therapy requires knowledge of how drugs interact at inhibitory ...concentrations. More than 50 years ago, it was noted that, if bactericidal drugs are most potent with actively dividing cells, then the inhibition of growth induced by a bacteriostatic drug should result in an overall reduction of efficacy when the drug is used in combination with a bactericidal drug. Our goal here was to investigate this hypothesis systematically. We first constructed time-kill curves using five different antibiotics at clinically relevant concentrations, and we observed antagonism between bactericidal and bacteriostatic drugs. We extended our investigation by performing a screen of pairwise combinations of 21 different antibiotics at subinhibitory concentrations, and we found that strong antagonistic interactions were enriched significantly among combinations of bacteriostatic and bactericidal drugs. Finally, since our hypothesis relies on phenotypic effects produced by different drug classes, we recreated these experiments in a microfluidic device and performed time-lapse microscopy to directly observe and quantify the growth and division of individual cells with controlled antibiotic concentrations. While our single-cell observations supported the antagonism between bacteriostatic and bactericidal drugs, they revealed an unexpected variety of cellular responses to antagonistic drug combinations, suggesting that multiple mechanisms underlie the interactions.
Hyaluronan, a linear glycosaminoglycan comprising D-N-acetylglucosamine and D-glucuronic acid, is the main component of the extracellular matrix. Its influence on cell proliferation, migration, ...inflammation, signalling, and other functions, depends heavily on its molecular weight and chemical modification. Unsaturated HA oligosaccharides are available in defined length and purity. Their potential therapeutic utility can be further improved by chemical modification, e. g., reduction. No synthesis of such modified oligosaccharides, either stepwise or by hyaluronan cleavage, has been reported yet.
Here we show a three-step synthesis (esterification, depolymerization and reduction) of unsaturated even numbered hyaluronan oligosaccharides with carboxylates and the reducing terminus reduced to an alcohol. Particular oligosaccharides were synthesised. The modified oligosaccharides are not cleaved by mammalian or bacterial hyaluronidase and do not affect the growth of mouse and human fibroblasts. Further, MTT and NRU viability tests showed that they inhibit the growth of human colon carcinoma cells HT-29 by 20–50 % in concentrations 500–1000 μg/mL. Interestingly, this effect takes place regardless of CD44 receptor expression and was not observed with unmodified HA oligosaccharides.
These compounds could serve as enzymatically stable building blocks for biologically active substances.
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•Novel water-soluble chitosan-isoniazid conjugates were prepared and characterized.•Conjugates exhibit high mycobacterial activity against Mycobacterium tuberculosis.•Toxicity tests revealed a lower ...toxicity for the conjugates compared with isoniazid.
Novel water-soluble chitosan-isoniazid conjugates were synthesized by two methods: (1) the carbodiimide method using isoniazid (INH) and N-(2-carboxyethyl)chitosan (CEC), and (2) the reaction between INH and N-(3-chloro-2-hydroxypropyl)chitosan (CHPC). The solubility of the conjugates under physiological conditions was enhanced by phosphorylation. Method (1) is preferable in terms of obtaining conjugates with a high content of active substance; depending on reaction conditions, the degree of substitution in the INH-CEC conjugates varies from 0.08 tо 0.39. Ultrasound treatment increased the reaction rate by a factor of 1.3–1.5, but caused partial degradation of the polymer. Consecutive modification led to a considerable decrease in polymer biodegradability in the following order: chitosan>CEC or CHPC>conjugate. In vitro screening of the antimicrobial activity against Mycobacterium tuberculosis H37Rv demonstrated a comparable or slightly higher minimum inhibitory concentration for conjugates than for INH itself (0.20, 0.25, and 1.05μg INH/mL for INH, CEC-INH, and CHPC-INH, respectively). A slug mucosal irritation test employing Limax flavus revealed a lower toxicity for the conjugates than for INH by a factor of 3–4; the most noticeable toxicity decrease was observed for the conjugates obtained by method (1). Studies of acute toxicity in mice revealed a 3–4-fold increase in median lethal dose for the conjugates compared with INH (LD50 210, 850, and 650mg INH/kg for INH, CEC-INH, and CHPC-INH, respectively).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Molecularly targeted therapies aim to obstruct cell autonomous programs required for tumor growth. We show that mitogen-activated protein kinase (MAPK) and cyclin-dependent kinase 4/6 inhibitors act ...in combination to suppress the proliferation of KRAS-mutant lung cancer cells while simultaneously provoking a natural killer (NK) cell surveillance program leading to tumor cell death. The drug combination, but neither agent alone, promotes retinoblastoma (RB) protein-mediated cellular senescence and activation of the immunomodulatory senescence-associated secretory phenotype (SASP). SASP components tumor necrosis factor-α and intercellular adhesion molecule-1 are required for NK cell surveillance of drug-treated tumor cells, which contributes to tumor regressions and prolonged survival in a KRAS-mutant lung cancer mouse model. Therefore, molecularly targeted agents capable of inducing senescence can produce tumor control through non-cell autonomous mechanisms involving NK cell surveillance.
Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g., tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries, and ...grapes) and in plants or botanical products commonly used in traditional medicine (e.g., Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Its anti-oxidant/anti-inflammatory effects have been demonstrated in various disease models, including those for encephalomyelitis, diabetes, asthma, and carcinogenesis. Moreover, kaempferol act as a scavenger of free radicals and superoxide radicals as well as preserve the activity of various anti-oxidant enzymes such as catalase, glutathione peroxidase, and glutathione-S-transferase. The anticancer effect of this flavonoid is mediated through different modes of action, including anti-proliferation, apoptosis induction, cell-cycle arrest, generation of reactive oxygen species (ROS), and anti-metastasis/anti-angiogenesis activities. In addition, kaempferol was found to exhibit its anticancer activity through the modulation of multiple molecular targets including p53 and STAT3, through the activation of caspases, and through the generation of ROS. The anti-tumor effects of kaempferol have also been investigated in tumor-bearing mice. The combination of kaempferol and conventional chemotherapeutic drugs produces a greater therapeutic effect than the latter, as well as reduces the toxicity of the latter. In this review, we summarize the anti-oxidant/anti-inflammatory and anticancer effects of kaempferol with a focus on its molecular targets and the possible use of this flavonoid for the treatment of inflammatory diseases and cancer.
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•Kaempferol acts as both a chemopreventive and chemotherapeutic.•It acts to ameliorate various disorders, importantly including cancer.•Kaempferol targets various key players involved in cancer development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In the presented study, electrochemical oxidation of five anticancer drugs (5-fluorouracil (5-FU), ifosfamide (IF), cyclophosphamide (CF), methotrexate (MTX), imatinib (IMB)) using boron doped ...diamond (BDD) electrode was investigated. In the first step the operating parameters of electrolysis were optimized. Studies have demonstrated a significant influence of applying current density, temperature, pH of solution and initial concentration of 5-FU on the process efficiency. A comparison of the decomposition rate of all the tested drugs showed a decrease in the pseudo-first order rate constants in the following order: k(IMB) > k(MTX) > k(CF) ≈ k(IF) > k(5-FU). Mineralization current efficiency (MCE) was determined for all the drugs based on the removal amount of total organic carbon (TOC) and their values decreased in the same order as values of drug degradation rate k. Based on the identified degradation products, electrochemical oxidation pathways of the decomposed drugs were proposed. In the case of CF, IF and 5-FU the degradation process occurred mainly through ketonization, hydroxylation and dehalogenation, while MTX and IMB were decomposed by attack of hydroxyl radicals on benzyl position in parent compounds. An important part of the research was the evaluation of eco-toxicity of electrochemically treated drug solutions against Lemna minor. Toxicity of initial 5-FU and MTX solutions towards L. minor were observed but after electrochemical treatment its toxicity decreased. The opposite trend was observed for CF and IF. In this case no significant toxicity was observed for the initial solutions of these drugs, while after electrochemical treatment an increase in growth inhibition of L. minor was found.
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•New data of electrochemical oxidation of five anticancer drugs were obtained.•CF, IF and 5-FU were more resistant to electrochemical oxidation than MTX and IMB.•Effect of current density, temperature, pH, concentration of drug were determined.•The degradation pathways for five anticancer drugs were proposed.•Toxicity of 5-FU and MTX towards L. minor decreased with degradation process.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Cytostatic drugs have been widely used for chemotherapy for decades. However, many of them have been categorized as carcinogenic, mutagenic and teratogenic compounds, triggering widespread concerns ...about their occupational exposure and ecotoxicological risks to the environment. This review focuses on trace presence, fate and ecotoxicity of various cytostatic compounds in the environment, with an emphasis on the major sources contributing to their environmental concentrations. Past records have documented findings mainly on hospital effluents though little effort has been directed to household discharges. There is also a lack in physico-chemical data for forecasting the chemodynamics of cytostatics in natural waters along with its human metabolites and environmental transformation products. In this light, obtaining comprehensive ecotoxicity data is becoming pressingly crucial to determine their actual impacts on the ecosystem. Literature review also reveals urinary excretion as a major contributor to various cytostatic residues appeared in the water cycle. As such, engaging urine source-separation as a part of control strategy holds a rosy prospect of addressing the “emerging” contamination issue. State-of-the-art treatment technologies should be incorporated to further remove cytostatic residues from the source-separating urine stream. The benefits, limitations and trends of development in this domain are covered for membrane bio-reactor, reverse/forward osmosis and advanced oxidation processes. Despite the respective seeming advantages of source separation and treatment technology, a combined strategy may cost-effectively prevent the cytostatic residues from seeping into the environment. However, the combination calls for further evaluation on the associated technological, social-economic and administrative issues at hand.
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► We review the environmental occurrence, fate and ecotoxicity of cytostatic drugs. ► Four major sources contributing to the environmental cytostatics are analyzed. ► Urine source separation promises to mitigate cytostatic contamination. ► We discuss the pros and cons and research gaps of various treatment technologies. ► Combining source separation strategy with end-of-pipe technology may serve better.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Cytostatic agents that interfere with specific cellular components to prevent cancer cell growth offer an attractive alternative, or complement, to traditional cytotoxic chemotherapy. Here, we ...describe the synthesis and characterization of a new binuclear Ru(II) -Pt(II) complex Ru(tpy)(tpypma)Pt(Cl)(DMSO)(3+) (tpy=2,2':6',2''-terpyridine and tpypma=4-(2,2':6',2''-terpyridine-4'-yl)-N-(pyridin-2-ylmethyl)aniline), VR54, which employs the extended terpyridine tpypma ligand to link the two metal centres. In cell-free conditions, VR54 binds DNA by non-intercalative reversible mechanisms (Kb =1.3×10(5) M(-1) ) and does not irreversibly bind guanosine. Cellular studies reveal that VR54 suppresses proliferation of A2780 ovarian cancer cells with no cross-resistance in the A2780CIS cisplatin-resistant cell line. Through the preparation of mononuclear Ru(II) and Pt(II) structural derivatives it was determined that both metal centres are required for this anti-proliferative activity. In stark contrast to cisplatin, VR54 neither activates the DNA-damage response network nor induces significant levels of cell death. Instead, VR54 is cytostatic and inhibits cell proliferation by up-regulating the cyclin-dependent kinase inhibitor p27(KIP1) and inhibiting retinoblastoma protein phosphorylation, which blocks entry into S phase and results in G1 cell cycle arrest. Thus, VR54 inhibits cancer cell growth by a gain of function at the G1 restriction point. This is the first metal-coordination compound to demonstrate such activity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Summary Background In head-to-head comparisons of coronary drug-eluting stents, the primary endpoint is traditionally assessed after 9–12 months. However, the optimum timepoint for this assessment ...remains unclear. In this study, we assessed clinical outcomes at up to 5 years' follow-up in patients who received two different types of drug-eluting stents. Methods We undertook this multicentre, open-label, randomised superiority trial at five percutaneous coronary intervention centres in Denmark. We randomly allocated 2332 eligible adult patients (≥18 years of age) with an indication for drug-eluting stent implantation to the zotarolimus-eluting Endeavor Sprint stent (Medtronic, Santa Rosa, CA, USA) or the sirolimus-eluting Cypher Select Plus stent (Cordis, Johnson & Johnson, Warren, NJ, USA). Randomisation of participants was achieved by computer-generated block randomisation and a telephone allocation service. The primary endpoint of the SORT OUT III study was a composite of major adverse cardiac events—cardiac death, myocardial infarction, and target vessel revascularisation—at 9 months' follow-up. In this study, endpoints included the occurrence of major adverse cardiac events and definite stent thrombosis at follow-up times of up to 5 years. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov , number NCT00660478. Findings We randomly allocated 1162 patients to receive the zotarolimus-eluting stent and 1170 to the sirolimus-eluting stent. At 5-year follow-up, rates of major adverse cardiac events were similar in patients treated with both types of stents (zotarolimus-eluting stents 197/1162 17·0% vs sirolimus-eluting stents 182/1170 15·6%; odds ratio OR 1·10, 95% CI 0·88–1·37; p=0·40). This finding was indicative of the directly contrasting results for rates of major adverse cardiac events at 1-year follow up (zotarolimus 93/1162 8·0% vs sirolimus 46/1170 3·9%; OR 2·13, 95% CI 1·48–3·07; p<0·0001) compared with those at follow-up between 1 and 5 years (104 9·0% vs 136 11·6%; OR 0·78, 95% CI 0·59–1·02; p=0·071). At 1-year follow-up, definite stent thrombosis was more frequent after implantation of the zotarolimus-eluting stent (13/1162 1·1%) than the sirolimus-eluting stent (4/1170 0·3%; OR 3·34, 95% CI 1·08–10·3; p=0·036), whereas the opposite finding was recorded for between 1 and 5 years' follow-up (zotarolimus-eluting stent 1/1162 0·1% vs sirolimus-eluting stent 21/1170 1·8%, OR 0·05, 95% CI 0·01–0·36; p=0·003). 26 of 88 (30%) target lesion revascularisations in the zotarolimus-eluting stent group occurred between 1 and 5 years' follow-up, whereas 54 of 70 (77%) of those in the sirolimus-eluting stent group occurred during this follow-up period. Interpretation The superiority of sirolimus-eluting stents compared with zotarolimus-eluting stents at 1-year follow-up was lost after 5 years. The traditional 1-year primary endpoint assessment therefore might be insufficient to predict 5-year clinical outcomes in patients treated with coronary drug-eluting stent implantation. Funding Cordis and Medtronic.
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Azidation (TMSN
3, SnCl
4) of a 9:1 mixture of
trans- and
cis-5-acetoxy-2-methylisoxazolidin-3-yl-3-phosphonates at the anomeric carbon atom led to the formation of the equimolar mixture of
cis- and
...trans-5-azido-2-methylisoxazolidin-3-yl-3-phosphonates, which were efficiently separated. The 1,3-dipolar cycloaddition of pure
trans- and
cis-5-azidoisoxazolidin-3-yl-3-phosphonates with selected alkynes gave the respective nucleoside mimetics containing a 1,2,3-triazole linker. The (1,2,3-triazolyl)isoxazolidine phosphonates obtained herein were evaluated in vitro for activity against a variety of DNA and RNA viruses. None of the compounds were endowed with antiviral activity at subtoxic concentrations. Compounds
15f–
j and
16f–
j were cytostatic in the higher micromolar range.
Inhibitory activity of cell proliferation for HEL cells as well as L1210, CEM and HeLa cells of several (1,2,3-triazolyl)isoxazolidine phosphonates was evaluated. The unsubstituted and fluoro-substituted phenyl derivatives appeared cytostatic (CC
50 40–250
μM).
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► An isoxazolidine-3-yl-3-phosphonate skeleton and nucleobases linked by 1,2,3-triazole. ► Efficient azidation of 5-acetoxy-2-methylisoxazolidin-3-yl-3-phosphonates. ► Nucleoside mimetics from 5-azido-2-methylisoxazolidin-3-yl-3-phosphonates. ► Cytostatic substituted (1,2,3-triazolyl)isoxazolidine phosphonates.
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