scholarly journals Antibiotic collateral sensitivity is contingent on the repeatability of evolution

2017 ◽  
Author(s):  
Daniel Nichol ◽  
Joseph Rutter ◽  
Christopher Bryant ◽  
Andrea M Hujer ◽  
Sai Lek ◽  
...  
Keyword(s):  
Experimental Evolution ◽  
Treatment Strategies ◽  
Therapeutic Benefit ◽  
Cross Resistance ◽  
Health Crisis ◽  
Collateral Sensitivity ◽  
Drug Regimens ◽  
Novel Treatment Strategies ◽  
Increased Susceptibility

AbstractAntibiotic resistance represents a growing health crisis that necessitates the immediate discovery of novel treatment strategies. One such strategy is the identification of collateral sensitivities, wherein evolution under a first drug induces susceptibility to a second. Here, we report that sequential drug regimens derived from in vitro evolution experiments may have overstated therapeutic benefit, predicting a collaterally sensitive response where cross resistance ultimately occurs. We quantify the likelihood of this phenomenon by use of a mathematical model parametrised with combinatorially complete fitness landscapes for Escherichia coli. Through experimental evolution we then verify that a second drug can indeed stochastically exhibit either increased susceptibility or increased resistance when following a first. Genetic divergence is confirmed as the driver of this differential response through targeted and whole genome sequencing. Taken together, these results highlight that the success of evolutionarily-informed therapies is predicated on a rigorous probabilistic understanding of the contingencies that arise during the evolution of drug resistance.

scholarly journals Molecular mechanisms underpinning sarcomas and implications for current and future therapy

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Victoria Damerell ◽  
Michael S. Pepper ◽  
Sharon Prince
Keyword(s):  
Molecular Mechanisms ◽  
Epithelial To Mesenchymal Transition ◽  
Treatment Strategies ◽  
Mesenchymal Transition ◽  
Mesenchymal To Epithelial Transition ◽  
Cells Of Origin ◽  
Novel Treatment Strategies ◽  
Future Therapy

AbstractSarcomas are complex mesenchymal neoplasms with a poor prognosis. Their clinical management is highly challenging due to their heterogeneity and insensitivity to current treatments. Although there have been advances in understanding specific genomic alterations and genetic mutations driving sarcomagenesis, the underlying molecular mechanisms, which are likely to be unique for each sarcoma subtype, are not fully understood. This is in part due to a lack of consensus on the cells of origin, but there is now mounting evidence that they originate from mesenchymal stromal/stem cells (MSCs). To identify novel treatment strategies for sarcomas, research in recent years has adopted a mechanism-based search for molecular markers for targeted therapy which has included recapitulating sarcomagenesis using in vitro and in vivo MSC models. This review provides a comprehensive up to date overview of the molecular mechanisms that underpin sarcomagenesis, the contribution of MSCs to modelling sarcomagenesis in vivo, as well as novel topics such as the role of epithelial-to-mesenchymal-transition (EMT)/mesenchymal-to-epithelial-transition (MET) plasticity, exosomes, and microRNAs in sarcomagenesis. It also reviews current therapeutic options including ongoing pre-clinical and clinical studies for targeted sarcoma therapy and discusses new therapeutic avenues such as targeting recently identified molecular pathways and key transcription factors.

scholarly journals Antimicrobial activity of a novel bioengineered honey against non-typeable Haemophilus influenzae biofilms: an in vitro study

2018 ◽  
Vol 71 (6) ◽  
pp. 554-558 ◽  
Author(s):  
Rachel S Newby ◽  
Matthew Dryden ◽  
Raymond N Allan ◽  
Rami J Salib
Keyword(s):  
Haemophilus Influenzae ◽  
Treatment Strategies ◽  
In Vitro Study ◽  
Opportunistic Pathogen ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Chronic Respiratory Diseases ◽  
Novel Treatment ◽  
Novel Treatment Strategies

The opportunistic pathogen non-typeable Haemophilus influenzae (NTHi) plays an important role in many chronic respiratory diseases including otitis media, chronic rhinosinusitis, cystic fibrosis and chronic obstructive pulmonary disease. Biofilm formation has been implicated in NTHi colonisation, persistence of infection and recalcitrance towards antimicrobials. There is therefore a pressing need for the development of novel treatment strategies that are effective against NTHi biofilm-associated diseases. SurgihoneyRO is a honey-based product that has been bioengineered to enable the slow release of H2O2, a reactive oxygen species to which H. influenzae is susceptible. Treatment of established NTHi biofilms with SurgihoneyRO significantly reduced biofilm viability through enhanced H2O2 production and was shown to be more effective than the conventional antibiotic co-amoxiclav.

scholarly journals Resistance-Guided Treatment of Gonorrhea: A Prospective Clinical Study

2020 ◽  
Author(s):  
Jeffrey D Klausner ◽  
Claire C Bristow ◽  
Olusegun O Soge ◽  
Akbar Shahkolahi ◽  
Toni Waymer ◽  
...  
Keyword(s):  
Single Dose ◽  
Clinical Study ◽  
Scale Up ◽  
Treatment Strategies ◽  
Prospective Clinical Study ◽  
Dose Oral ◽  
Novel Treatment Strategies ◽  
Oral Ciprofloxacin ◽  
Culture Positive

Abstract Background Novel treatment strategies to slow the continued emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae are urgently needed. A molecular assay that predicts in vitro ciprofloxacin susceptibility is now available but has not been systematically studied in human infections. Methods Using a genotypic polymerase chain reaction assay to determine the status of the N. gonorrhoeae gyrase subunit A serine 91 codon, we conducted a multisite prospective clinical study of the efficacy of a single oral dose of ciprofloxacin 500 mg in patients with culture-positive gonorrhea. Follow-up specimens for culture were collected to determine microbiological cure 5–10 days post-treatment. Results Of the 106 subjects possessing culture-positive infections with wild-type gyrA serine N. gonorrhoeae genotype, the efficacy of single-dose oral ciprofloxacin treatment in the per-protocol population was 100% (95% 1-sided confidence interval, 97.5–100%). Conclusions Resistance-guided treatment of N. gonorrhoeae infections with single-dose oral ciprofloxacin was highly efficacious. The widespread introduction and scale-up of gyrA serine 91 genotyping in N. gonorrhoeae infections could have substantial medical and public health benefits in settings where the majority of gonococcal infections are ciprofloxacin susceptible. Clinical Trials Registration NCT02961751.

scholarly journals Therapeutic Effects of Curcumin—From Traditional Past to Present and Future Clinical Applications

2019 ◽  
Vol 20 (15) ◽  
pp. 3757 ◽  
Author(s):  
Beatrice Bachmeier ◽  
Dieter Melchart
Keyword(s):  
Molecular Mechanisms ◽  
Malignant Tumors ◽  
Scientific Evidence ◽  
Treatment Strategies ◽  
Therapeutic Effects ◽  
Microbial Infection ◽  
Therapeutic Benefits ◽  
Novel Treatment Strategies

The efficacy of the plant-derived polyphenol curcumin, in various aspects of health and wellbeing, is matter of public interest. An internet search of the term “Curcumin” displays about 12 million hits. Among the multitudinous information presented on partly doubtful websites, there are reports attracting the reader with promises ranging from eternal youth to cures for incurable diseases. Unfortunately, many of these reports are not based on scientific evidence, but they feed the desideratum of the reader for a “miracle cure”. This circumstance makes it very difficult for researchers, who work in a scientifically sound and evidence-based manner on the therapeutic benefits (or side effects) of curcumin, to demarcate their results from sensational reports that circulate in the web and in other media. This is only one of many obstacles making it difficult to pave curcumin’s way into clinical application; others are its nonpatentability and low economic usability. A further impediment comes from scientists who never worked with curcumin or any other natural plant-derived compound in their own labs. They have never tested these compounds in any scientific assay, neither in vitro nor in vivo; however, they claim, in a sometimes polemic manner, that everything that has so far been published on curcumin’s molecular effects is based on artefacts. The here presented Special Issue comprises a collection of five scientifically sound articles and nine reviews reporting on the therapeutic benefits and the molecular mechanisms of curcumin or of chemically modified curcumin in various diseases ranging from malignant tumors to chronic diseases, microbial infection, and even neurodegenerative diseases. The excellent results of the scientific projects that underlie the five original papers give reason to hope that curcumin will be part of novel treatment strategies in the near future—either as monotherapy or in combination with other drugs or therapeutic applications.

scholarly journals Synergic Interaction between Permethrin and Bt toxins discovered using RNA-seq

2019 ◽  
Author(s):  
Takuma Sakamoto ◽  
Toshinori Kozaki ◽  
Norichika Ogata
Keyword(s):  
Differentially Expressed Gene ◽  
Model Organisms ◽  
Cross Resistance ◽  
Agricultural Pests ◽  
Bt Toxin ◽  
Development Of Resistance ◽  
Bt Toxins ◽  
Increased Susceptibility

AbstractActing against the development of resistance to antibiotics and insecticides, involving negatively correlated cross-resistance (NCR) is an alternative to use- and-discard approach. It is termed NCR that toxic chemicals interact with each other and resistance of target organisms to one chemical is sometimes associated with increased susceptibility to a second chemical when; an allele confers resistance to one toxic chemical and hyper-susceptibility to another, NCR occurs. However, only 11 toxin pairs have been revealed to cause NCR in insects. Finding novel NCRs is needed for integrated pest management. We analyzed permethrin, an insecticide, induced transcriptomes of cultured fat bodies of the silkworm Bombyx mori, a lepidopteran model insect. Differentially expressed gene analyses suggested Bacillus thuringiensis (Bt) toxin was an NCR toxin of permethrin. NCR to permethrin and Bt toxins in Thysanoplusia intermixta, the agricultural pest moth, was examined; the children of permethrin survivor T. intermixta had increased susceptibility to Bt toxin. A novel NCR toxin pair, permethrin and Bt toxin, was discovered. The screening and developmental method for negatively correlated cross-resistance toxins established in this study was effective, in vitro screening using model organisms and in vivo verification using agricultural pests.

A Comparison of the Lethal and Kinetic Effects of Doxorubicin and 4′-EPI-Doxorubicin in Vitro

1982 ◽  
Vol 68 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Bridget T. Hill ◽  
Richard D.H. Whelan
Keyword(s):  
Cell Lines ◽  
Cross Resistance ◽  
Drug Resistant ◽  
Human Cell Lines ◽  
Lethal Effects ◽  
Collateral Sensitivity ◽  
L5178y Cell ◽  
Kinetic Effects ◽  
Resistant Cells

« In vitro » lethal and kinetic effects of 4′-epi-doxorubicin (EPI-DXR) have been established and compared with those of doxorubicin (14-hydroxy-daunorubicin, adriamycin, NSC-123127, DXR). Both drugs show comparable cytotoxicity against a range of murine and human cell lines. Cytotoxicity increases exponentially with drug concentration and with duration of exposure. EPI-DXR like DXR exerts maximal lethal effects during the late S and G2 phases of the cycle in synchronised N1L8 Syrian hamster cells. Flow microfluorimetric data and measurements of mitotic indices provide evidence of population arrest in G2 with both drugs. Responses of various drug-resistant L5178Y cell lines were similar for DXR and EPI-DXR: (i) DXR-resistant cells exhibit complete cross-resistance to EPI-DXR, (ii) vincristine-resistant cells are cross-resistant to DXR and EPI-DXR, and (iii) methotrexate-resistant and 5-fluorouracil-resistant cells show collateral sensitivity to both drugs. These studies emphasise the similarities of DXR and EPI-DXR.

scholarly journals Activity of Aztreonam in Combination with Avibactam, Clavulanate, Relebactam, and Vaborbactam against Multidrug-Resistant Stenotrophomonas maltophilia

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
M. Biagi ◽  
D. Lamm ◽  
K. Meyer ◽  
A. Vialichka ◽  
M. Jurkovic ◽  
...  
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Treatment Strategies ◽  
Multidrug Resistant ◽  
Content Type ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Novel Treatment Strategies

ABSTRACT The intrinsic L1 metallo- and L2 serine-β-lactamases in Stenotrophomonas maltophilia make it naturally multidrug resistant and difficult to treat. There is a need to identify novel treatment strategies for this pathogen, especially against isolates resistant to first-line agents. Aztreonam in combination with avibactam has demonstrated potential, although data on other aztreonam–β-lactamase inhibitor (BLI) combinations are lacking. Additionally, molecular mechanisms for reduced susceptibility to these combinations have not been explored. The objectives of this study were to evaluate and compare the in vitro activities and to understand the mechanisms of resistance to aztreonam in combination with avibactam, clavulanate, relebactam, and vaborbactam against S. maltophilia. A panel of 47 clinical S. maltophilia strains nonsusceptible to levofloxacin and/or trimethoprim-sulfamethoxazole were tested against each aztreonam-BLI combination via broth microdilution, and 6 isolates were then evaluated in time-kill analyses. Three isolates with various aztreonam-BLI MICs were subjected to whole-genome sequencing and quantitative reverse transcriptase PCR. Avibactam restored aztreonam susceptibility in 98% of aztreonam-resistant isolates, compared to 61, 71, and 15% with clavulanate, relebactam, and vaborbactam, respectively. The addition of avibactam to aztreonam resulted in a ≥2-log10-CFU/ml decrease at 24 h versus aztreonam alone against 5/6 isolates compared to 1/6 with clavulanate, 4/6 with relebactam, and 2/6 with vaborbactam. Molecular analyses revealed that decreased susceptibility to aztreonam-avibactam was associated with increased expression of genes encoding L1 and L2, as well as the efflux pump (smeABC). Aztreonam-avibactam is the most promising BLI-combination against multidrug-resistant S. maltophilia. Decreased susceptibility may be due to the combination of overexpressed β-lactamases and efflux pumps. Further studies evaluating this combination against S. maltophilia are warranted.

Antitumor alkylating agents: in vitro cross-resistance and collateral sensitivity studies

1993 ◽  
Vol 33 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Emil Frei ◽  
Sylvia A. Holden ◽  
Rene Gonin ◽  
David J. Waxman ◽  
Beverly A. Teicher
Keyword(s):  
Alkylating Agents ◽  
Cross Resistance ◽  
Collateral Sensitivity ◽  
Sensitivity Studies ◽  
Antitumor Alkylating Agents

scholarly journals Pathogenesis of Keratinocyte Carcinomas and the Therapeutic Potential of Medicinal Plants and Phytochemicals

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1979
Author(s):  
Andrea Jess Josiah ◽  
Danielle Twilley ◽  
Sreejarani Kesavan Pillai ◽  
Suprakas Sinha Ray ◽  
Namrita Lall
Keyword(s):  
Cell Carcinoma ◽  
Therapeutic Potential ◽  
Treatment Strategies ◽  
In Vivo Studies ◽  
Contributing Factors ◽  
Alternative Approach ◽  
Transdermal Drug Delivery Systems ◽  
Novel Treatment Strategies

Keratinocyte carcinoma (KC) is a form of skin cancer that develops in keratinocytes, which are the predominant cells present in the epidermis layer of the skin. Keratinocyte carcinoma comprises two sub-types, namely basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). This review provides a holistic literature assessment of the origin, diagnosis methods, contributing factors, and current topical treatments of KC. Additionally, it explores the increase in KC cases that occurred globally over the past ten years. One of the principal concepts highlighted in this article is the adverse effects linked to conventional treatment methods of KC and how novel treatment strategies that combine phytochemistry and transdermal drug delivery systems offer an alternative approach for treatment. However, more in vitro and in vivo studies are required to fully assess the efficacy, mechanism of action, and safety profile of these phytochemical based transdermal chemotherapeutics.

scholarly journals Directed evolution predicts cytochrome b G37V target site modification as probable adaptive mechanism towards the QiI fungicide fenpicoxamid in Zymoseptoria tritici

2021 ◽  
Author(s):  
Guillaume Fouché ◽  
Thomas Michel ◽  
Anaïs Lalève ◽  
Nick X Wang ◽  
David H Young ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Cytochrome B ◽  
Experimental Evolution ◽  
Pathogenic Fungus ◽  
Resistance Mechanism ◽  
Cross Resistance ◽  
List Type ◽  
Adaptive Traits ◽  
Zymoseptoria Tritici

ABSTRACTAcquired resistance is a threat for antifungal efficacy in medicine and agriculture. The diversity of possible resistance mechanisms, as well as the highly adaptive traits of pathogens make it difficult to predict evolutionary outcomes of treatments. We used directed evolution as an approach to assess the risk of resistance to the new fungicide fenpicoxamid in the wheat pathogenic fungus Zymoseptoria tritici. Fenpicoxamid inhibits complexIII of the respiratory chain at the ubiquinone reduction site (Qi site) of the mitochondrially encoded cytochrome b, a different site than the widely-used strobilurins which the respiratory complex by binding to the ubiquinol oxidation site (Qo site). We identified the G37V change, within the cytochrome b Qi site, as the most likely resistance mechanism to be selected in Z. tritici. This change triggered high fenpicoxamid resistance and halved the enzymatic activity of cytochrome b, despite no significant penalty for in vitro growth. In addition, we identified a negative cross-resistance between isolates harboring G37V or G143A, a Qo site change previously selected by strobilurins. Moreover, double mutants were less resistant to both QiIs and QoIs compared to single mutants. This work is a proof of concept that experimental evolution can be used to predict adaptation to fungicides, and provides new perspectives for the management of QiIs.Originality-Significance StatementThe highly adaptive traits of pathogens render evolutionary outcomes of antifungal treatments difficult to predict.We used directed evolution to assess the risk of resistance to the new fungicide fenpicoxamid in the wheat pathogenic fungus Zymoseptoria tritici.We identified a target modification as the most likely resistance mechanism to be selected.This change triggered high fenpicoxamid resistance and halved the activity of the target enzyme despite no significant penalty for in vitro growth.This work supports the use of experimental evolution as a method to predict adaptation to fungicides and provides important information for the management of QiIs.

Sign in / Sign up

Export Citation Format

Share Document