scholarly journals Genome-wide analysis of experimentally evolved Candida auris reveals multiple novel mechanisms of multidrug-resistance

2020 ◽  
Author(s):  
Hans Carolus ◽  
Siebe Pierson ◽  
José F. Muñoz ◽  
Ana Subotić ◽  
Rita B. Cruz ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Molecular Mechanisms ◽  
Chromosome 1 ◽  
Cross Resistance ◽  
Novel Mutations ◽  
Candida Auris ◽  
Genome Wide ◽  
High Concern

AbstractCandida auris is globally recognized as an opportunistic fungal pathogen of high concern, due to its extensive multidrug-resistance (MDR). Still, molecular mechanisms of MDR are largely unexplored. This is the first account of genome wide evolution of MDR in C. auris obtained through serial in vitro exposure to azoles, polyenes and echinocandins. We show the stepwise accumulation of multiple novel mutations in genes known and unknown in antifungal drug resistance, albeit almost all new for C. auris. Echinocandin resistance evolved through a codon deletion in FKS1 accompanied by a substitution in FKS1 hot spot 3. Mutations in ERG3 and CIS2 further increased the echinocandin MIC. Decreased azole susceptibility was acquired through a gain of function mutation in transcription factor TAC1b yielding overexpression of the drug efflux pump Cdr1; a segmental duplication of chromosome 1 containing ERG11; and a whole chromosome 5 duplication, which contains TAC1b. The latter was associated with increased expression of ERG11, TAC1b and CDR2, but not CDR1. The simultaneous emergence of nonsense mutations in ERG3 and ERG11, presumably leading to the abrogation of ergosterol synthesis, was shown to decrease amphotericin B susceptibility, accompanied with fluconazole cross resistance. A mutation in MEC3, a gene mainly known for its role in DNA damage homeostasis, further increased the polyene MIC. Overall, this study shows the alarming potential and diversity for MDR development in C. auris, even in a clade until now not associated with MDR (clade II), hereby stressing its clinical importance and the urge for future research.ImportanceC. auris is a recently discovered human fungal pathogens and has shown an alarming potential for multi- and pan-resistance towards all classes of antifungals most commonly used in the clinic. Currently, C. auris has been globally recognized as a nosocomial pathogen of high concern due to this evolutionary potential. So far, this is the first study in which the stepwise progression of MDR in C. auris is monitored in vitro. Multiple novel mutations in known ‘resistance genes’ and genes previously not or vaguely associated with drug resistance reveal rapid MDR evolution in a C. auris clade II isolate. Additionally, this study shows that in vitro experimental evolution can be a powerful tool to discover new drug resistance mechanisms, although it has its limitations.

scholarly journals Genome-wide analysis of experimentally evolved Candida auris reveals multiple novel mechanisms of multidrug-resistance

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Hans Carolus ◽  
Siebe Pierson ◽  
José F. Mun?oz ◽  
Ana Subotić ◽  
Rita B. Cruz ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Hot Spot ◽  
Chromosome 1 ◽  
Cross Resistance ◽  
Future Research ◽  
Candida Auris ◽  
Genome Wide

Candida auris is globally recognized as an opportunistic fungal pathogen of high concern, due to its extensive multidrug-resistance (MDR). Still, molecular mechanisms of MDR are largely unexplored. This is the first account of genome wide evolution of MDR in C. auris obtained through serial in vitro exposure to azoles, polyenes and echinocandins. We show the stepwise accumulation of multiple novel mutations in genes known and unknown in antifungal drug resistance, albeit almost all new for C. auris. Echinocandin resistance was accompanied by a codon deletion in FKS1hot spot 1 and a substitution in FKS1 ‘novel’ hot spot 3. Mutations in ERG3 and CIS2 further increased the echinocandin MIC. Decreased azole susceptibility was linked to a mutation in transcription factor TAC1b and overexpression of the drug efflux pump Cdr1; a segmental duplication of chromosome 1 containing ERG11; and a whole chromosome 5 duplication, which contains TAC1b. The latter was associated with increased expression of ERG11, TAC1band CDR2, but not CDR1. The simultaneous emergence of nonsense mutations in ERG3 and ERG11 was shown to decrease amphotericin B susceptibility, accompanied with fluconazole cross resistance. A mutation in MEC3, a gene mainly known for its role in DNA damage homeostasis, further increased the polyene MIC. Overall, this study shows the alarming potential and diversity for MDR development in C. auris, even in a clade until now not associated with MDR (clade II),hereby stressing its clinical importance and the urge for future research.

scholarly journals Genome-Wide Analysis of Experimentally Evolved Candida auris Reveals Multiple Novel Mechanisms of Multidrug Resistance

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Hans Carolus ◽  
Siebe Pierson ◽  
José F. Muñoz ◽  
Ana Subotić ◽  
Rita B. Cruz ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Fungal Pathogen ◽  
Hot Spot ◽  
Novel Mutations ◽  
Candida Auris ◽  
Content Type ◽  
Genome Wide ◽  
High Concern

ABSTRACT Candida auris is globally recognized as an opportunistic fungal pathogen of high concern, due to its extensive multidrug resistance (MDR). Still, molecular mechanisms of MDR are largely unexplored. This is the first account of genome-wide evolution of MDR in C. auris obtained through serial in vitro exposure to azoles, polyenes, and echinocandins. We show the stepwise accumulation of copy number variations and novel mutations in genes both known and unknown in antifungal drug resistance. Echinocandin resistance was accompanied by a codon deletion in FKS1 hot spot 1 and a substitution in FKS1 “novel” hot spot 3. Mutations in ERG3 and CIS2 further increased the echinocandin MIC. Decreased azole susceptibility was linked to a mutation in transcription factor TAC1b and overexpression of the drug efflux pump Cdr1, a segmental duplication of chromosome 1 containing ERG11, and a whole chromosome 5 duplication, which contains TAC1b. The latter was associated with increased expression of ERG11, TAC1b, and CDR2 but not CDR1. The simultaneous emergence of nonsense mutations in ERG3 and ERG11 was shown to decrease amphotericin B susceptibility, accompanied with fluconazole cross-resistance. A mutation in MEC3, a gene mainly known for its role in DNA damage homeostasis, further increased the polyene MIC. Overall, this study shows the alarming potential for and diversity of MDR development in C. auris, even in a clade until now not associated with MDR (clade II), stressing its clinical importance and the urge for future research. IMPORTANCE Candida auris is a recently discovered human fungal pathogen and has shown an alarming potential for developing multi- and pan-resistance toward all classes of antifungals most commonly used in the clinic. Currently, C. auris has been globally recognized as a nosocomial pathogen of high concern due to this evolutionary potential. So far, this is the first study in which the stepwise progression of multidrug resistance (MDR) in C. auris is monitored in vitro. Multiple novel mutations in known resistance genes and genes previously not or vaguely associated with drug resistance reveal rapid MDR evolution in a C. auris clade II isolate. Additionally, this study shows that in vitro experimental evolution can be a powerful tool to discover new drug resistance mechanisms, although it has its limitations.

scholarly journals Gene transfer of multidrug resistance into a factor-dependent human hematopoietic progenitor cell line: in vivo model for genetically transferred chemoprotection

Blood ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 2723-2731 ◽  
Author(s):  
P Schwarzenberger ◽  
S Spence ◽  
N Lohrey ◽  
T Kmiecik ◽  
DL Longo ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Gene Transfer ◽  
Hematopoietic Progenitor Cells ◽  
Mdr1 Gene ◽  
In Vivo Model ◽  
Hematopoietic Progenitor ◽  
Human Dna

To develop a rapid preclinical in vivo model to study gene transfer into human hematopoietic progenitor cells, MO-7e cells (CD-34+, c-kit+) were infected with multidrug resistance (MDR1)-containing retroviruses and then transplanted into nonobese diabetic severe combined immunodeficient mice (NOD SCID). MO-7e cells infected with a retrovirus encoding the human MDR1 cDNA showed integration, transcription, and expression of the transfered MDR1 gene. This resulted in a 20-fold increase in the resistance of MO-7e cells to paclitaxel in vitro. The expression of the MDR1 gene product was stable over a 6-month period in vitro without selection in colchicine. MO-7e and MDR1-infected MO-7e cells were transplanted into NOD SCID mice to determine whether MDR1 could confer drug resistance in vivo. A sensitive polymerase chain reaction method specific for human sequences was developed to quantitate the level of human cell engraftment in NOD SCID bone marrow (BM) cells. The percentage of human DNA in BM cells from MO-7e- transplanted mice was 10.9% and decreased to 0.7% in mice treated with paclitaxel. The percentage of human DNA in infected-MO-7e transplanted mice was 7.6% and that level was unchanged in mice treated with paclitaxel. These results show that expression of the MDR1 gene in human hematopoietic progenitor cells can confer functional drug resistance in an in vivo model.

scholarly journals The molecular mechanisms of multidrug resistance of human glioblastomas

2021 ◽  
Vol 67 (1) ◽  
pp. 20-28
Author(s):  
Alexandr Chernov ◽  
Irina Baldueva ◽  
Tatyana Nekhaeva ◽  
Elvira Galimova ◽  
Diana Alaverdian ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Drug Resistance ◽  
Transcription Factors ◽  
Growth Factors ◽  
Multidrug Resistance ◽  
Tumor Suppressor Genes ◽  
Molecular Mechanisms ◽  
Molecular Targets ◽  
Polymorphic Variants ◽  
Signal Transduction Proteins

In review discusses the phenomenon of drug resistance of GB in the context of the expression of ABC family transporter proteins and the processes of proliferation, angiogenesis, recurrence and death. The emphasis is on the identifying for molecular targets among growth factors, receptors, signal transduction proteins, microRNAs, transcription factors, proto-oncogenes, tumor suppressor genes and their polymorphic variants (SNPs) for the development and creation of targeted anticancer drugs.

scholarly journals Plasmid-Mediated Resistance to Thrombin-Induced Platelet Microbicidal Protein in Staphylococci: Role of theqacA Locus

1999 ◽  
Vol 43 (10) ◽  
pp. 2395-2399 ◽  
Author(s):  
Leon Iri Kupferwasser ◽  
Ronald A. Skurray ◽  
Melissa H. Brown ◽  
Neville Firth ◽  
Michael R. Yeaman ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Efflux Pump ◽  
Endothelial Damage ◽  
Cross Resistance ◽  
Cationic Peptide ◽  
Multidrug Resistance Gene ◽  
Phenotypic Resistance ◽  
Platelet Microbicidal Protein

ABSTRACT Thrombin-induced platelet microbicidal protein 1 (tPMP-1) is a small, cationic peptide released from rabbit platelets following thrombin stimulation. In vitro resistance to this peptide among strains of Staphylococcus aureus correlates with the survival advantage of such strains at sites of endothelial damage in humans as well as in experimental endovascular infections. The mechanisms involved in the phenotypic resistance of S. aureus to tPMP-1 are not fully delineated. The plasmid-encoded staphylococcal gene qacA mediates multidrug resistance to multiple organic cations via a proton motive force-dependent efflux pump. We studied whether the qacA gene might also confer resistance to cationic tPMP-1. Staphylococcal plasmids encoding qacA were found to confer resistance to tPMP-1 in an otherwise susceptible parental strain. Deletions which removed the region containing theqacA gene in the S. aureus multiresistance plasmid pSK1 abolished tPMP-1 resistance. Resistance to tPMP-1 in theqacA-bearing strains was inoculum independent but peptide concentration dependent, with the level of resistance decreasing at higher peptide concentrations for a given inoculum. There was no apparent cross-resistance in qacA-bearing strains to other endogenous cationic antimicrobial peptides which are structurally distinct from tPMP-1, including human neutrophil defensin 1, protamine, or the staphylococcal lantibiotics pep5 and nisin. These data demonstrate that the staphylococcal multidrug resistance geneqacA also mediates in vitro resistance to cationic tPMP-1.

Bioactive Compounds from Seaweed with Anti-Leukemic Activity: A Mini-Review on Carotenoids and Phlorotannins

2020 ◽  
Vol 20 (1) ◽  
pp. 39-53 ◽  
Author(s):  
Tânia P. Almeida ◽  
Alice A. Ramos ◽  
Joana Ferreira ◽  
Amaya Azqueta ◽  
Eduardo Rocha
Keyword(s):  
Drug Resistance ◽  
Bioactive Compounds ◽  
Myeloid Leukemia ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
First Line ◽  
In Vivo Models ◽  
Few Data

: Chronic Myeloid Leukemia (CML) represents 15-20% of all new cases of leukemia and is characterized by an uncontrolled proliferation of abnormal myeloid cells. Currently, the first-line of treatment involves Tyrosine Kinase Inhibitors (TKIs), which specifically inhibits the activity of the fusion protein BCR-ABL. However, resistance, mainly due to mutations, can occur. In the attempt to find more effective and less toxic therapies, several approaches are taken into consideration such as research of new anti-leukemic drugs and “combination chemotherapy” where different drugs that act by different mechanisms are used. Here, we reviewed the molecular mechanisms of CML, the main mechanisms of drug resistance and current strategies to enhance the therapeutic effect of TKIs in CML. Despite major advances in CML treatment, new, more potent anticancer drugs and with fewer side effects are needed. Marine organisms, and particularly seaweed, have a high diversity of bioactive compounds with some of them having anticancer activity in several in vitro and in vivo models. The state-of-art suggests that their use during cancer treatment may improve the outcome. We reviewed here the yet few data supporting anti-leukemic activity of some carotenoids and phlorotannins in some leukemia models. Also, strategies to overcome drug resistance are discussed, particularly the combination of conventional drugs with natural compounds.

scholarly journals Novel Regulatory Mechanisms of Pathogenicity and Virulence to Combat MDR inCandida albicans

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Saif Hameed ◽  
Zeeshan Fatima
Keyword(s):  
Drug Resistance ◽  
Molecular Mechanisms ◽  
Opportunistic Pathogen ◽  
Antifungal Drugs ◽  
Regulatory Mechanisms ◽  
Cross Resistance ◽  
Signaling Networks ◽  
Antifungal Drug Resistance ◽  
Human Fungal Pathogen ◽  
Major Factors

Continuous deployment of antifungals in treating infections caused by dimorphic opportunistic pathogenCandida albicanshas led to the emergence of drug resistance resulting in cross-resistance to many unrelated drugs, a phenomenon termed multidrug resistance (MDR). Despite the current understanding of major factors which contribute to MDR mechanisms, there are many lines of evidence suggesting that it is a complex interplay of multiple factors which may be contributed by still unknown mechanisms. Coincidentally with the increased usage of antifungal drugs, the number of reports for antifungal drug resistance has also increased which further highlights the need for understanding novel molecular mechanisms which can be explored to combat MDR, namely, ROS, iron, hypoxia, lipids, morphogenesis, and transcriptional and signaling networks. Considering the worrying evolution of MDR and significance ofC. albicansbeing the most prevalent human fungal pathogen, this review summarizes these new regulatory mechanisms which could be exploited to prevent MDR development inC. albicansas established from recent studies.

scholarly journals Mathematical modeling quantifies ERK-activity in response to inhibition of the BRAFV600E-MEK-ERK cascade

2021 ◽  
Author(s):  
Sara Hamis ◽  
Yury Kapelyukh ◽  
Aileen McLaren ◽  
Colin J. Henderson ◽  
C. Roland Wolf ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Drug Resistance ◽  
Chemical Reactions ◽  
Molecular Mechanisms ◽  
Braf Inhibitor ◽  
Mass Action ◽  
Model Parameters ◽  
Mass Action Kinetics ◽  
Erk Activity

AbstractSimultaneous inhibition of multiple components of the BRAF-MEK-ERK cascade (vertical inhibition) has become a standard of care for treating BRAF-mutant melanoma. However, the molecular mechanisms of how vertical inhibition synergistically suppress intracellular ERK activity, and as a consequence cell proliferation, are yet to be fully elucidated.In this study, we develop a mechanistic mathematical model that describes how the mutant BRAF-inhibitor, dabrafenib, and the MEK-inhibitor, trametinib, affect signaling through the BRAFV600E-MEK-ERK cascade. We formulate a system of chemical reactions that describes cascade signaling dynamics and, using mass action kinetics, the chemical reactions are re-expressed as ordinary differential equations. Using model parameters obtained from in vitro data available in the literature, these equations are solved numerically to obtain the temporal evolution of the concentrations of the components in the signaling cascade.Our mathematical model provides a quantitative method to compute how dabrafenib and trametinib can be used in combination to synergistically inhibit ERK activity in BRAFV600E mutant melanoma cells. This work elucidates molecular mechanisms of vertical inhibition of the BRAFV600E-MEK-ERK cascade and delineates how elevated cellular BRAF concentrations generate drug resistance to dabrafenib and trametinib. In addition, the computational simulations suggest that elevated ATP levels could be a factor in drug resistance to dabrafenib. The mathematical model that is developed in this study will have generic application in the improved design of anticancer combination therapies that target BRAF-MEK-ERK pathways.

scholarly journals LncRNA FEZF1-AS1 Promotes Multi-Drug Resistance of Gastric Cancer Cells via Upregulating ATG5

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhifu Gui ◽  
Zhenguo Zhao ◽  
Qi Sun ◽  
Guoyi Shao ◽  
Jianming Huang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Drug Resistance ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Underlying Mechanism ◽  
Multi Drug Resistance ◽  
Gastric Cancer Cells ◽  
Poor Overall Survival

Long non-coding RNAs (lncRNAs) play important roles in human cancers including gastric cancer (GC). Dysregulation of lncRNAs is involved in a variety of pathological activities associated with gastric cancer progression and chemo-resistance. However, the role and molecular mechanisms of FEZF1-AS1 in chemoresistance of GC remain unknown. In this study, we aimed to determine the role of FEZF1-AS1 in chemoresistance of GC. The level of FEZF1-AS1 in GC tissues and GC cell lines was assessed by qRT-PCR. Our results showed that the expression of FEZF1-AS1 was higher in gastric cancer tissues than in adjacent normal tissues. Multivariate analysis identified that high level of FEZF1-AS1 is an independent predictor for poor overall survival. Increased FEZF1-AS1 expression promoted gastric cancer cell proliferation in vitro. Additionally, FEZF1-AS1 was upregulated in chemo-resistant GC tissues. The regulatory effect of FEZF1-AS1 on multi-drug resistance (MDR) in GC cells and the underlying mechanism was investigated. It was found that increased FEZF1-AS1 expression promoted chemo-resistance of GC cells. Molecular interactions were determined by RNA immunoprecipitation (RIP) and the results showed that FEZF1-AS1 regulated chemo-resistance of GC cells through modulating autophagy by directly targeting ATG5. The proliferation and autophagy of GC cells promoted by overexpression of LncFEZF1-AS1 was suppressed when ATG5 was knocked down. Moreover, knockdown of FEZF1-AS1 inhibited tumor growth and increased 5-FU sensitivity in GC cells in vivo. Taken together, this study revealed that the FEZF1-AS1/ATG5 axis regulates MDR of GC cells via modulating autophagy.

scholarly journals Quantifying ERK activity in response to inhibition of the BRAFV600E-MEK-ERK cascade using mathematical modelling

2021 ◽  
Author(s):  
Sara J. Hamis ◽  
Yury Kapelyukh ◽  
Aileen McLaren ◽  
Colin J. Henderson ◽  
C. Roland Wolf ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Chemical Reactions ◽  
Molecular Mechanisms ◽  
Braf Inhibitor ◽  
Standard Of Care ◽  
Mek Inhibitor ◽  
Mass Action ◽  
Mass Action Kinetics ◽  
Erk Activity

Abstract Background Simultaneous inhibition of multiple components of the BRAF-MEK-ERK cascade (vertical inhibition) has become a standard of care for treating BRAF-mutant melanoma. However, the molecular mechanism of how vertical inhibition synergistically suppresses intracellular ERK activity, and consequently cell proliferation, are yet to be fully elucidated. Methods We develop a mechanistic mathematical model that describes how the mutant BRAF inhibitor, dabrafenib, and the MEK inhibitor, trametinib, affect BRAFV600E-MEK-ERK signalling. The model is based on a system of chemical reactions that describes cascade signalling dynamics. Using mass action kinetics, the chemical reactions are re-expressed as ordinary differential equations that are parameterised by in vitro data and solved numerically to obtain the temporal evolution of cascade component concentrations. Results The model provides a quantitative method to compute how dabrafenib and trametinib can be used in combination to synergistically inhibit ERK activity in BRAFV600E-mutant melanoma cells. The model elucidates molecular mechanisms of vertical inhibition of the BRAFV600E-MEK-ERK cascade and delineates how elevated BRAF concentrations generate drug resistance to dabrafenib and trametinib. The computational simulations further suggest that elevated ATP levels could be a factor in drug resistance to dabrafenib. Conclusions The model can be used to systematically motivate which dabrafenib–trametinib dose combinations, for treating BRAFV600E-mutated melanoma, warrant experimental investigation.

Sign in / Sign up

Export Citation Format

Share Document