scholarly journals Dose Optimization of Combined Linezolid and Fosfomycin against Enterococcus by Using an In Vitro Pharmacokinetic/Pharmacodynamic Model

2021 ◽  
Author(s):  
Jun Mao ◽  
Ting Li ◽  
Na Zhang ◽  
Shuaishuai Wang ◽  
Yaowen Li ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Adverse Effects ◽  
Combination Treatment ◽  
Drug Combination ◽  
Pharmacodynamic Model ◽  
Dose Optimization ◽  
Potential Mechanism

In this study, we found that linezolid combined with fosfomycin could kill Enterococcus in vitro and that the administered dose was significantly lower after the combination treatment, which could reduce adverse effects and the development of drug resistance. The potential mechanism of the two-drug combination against Enterococcus was revealed from a quantitative perspective, which is an important step toward dose optimization in simulated humans.

scholarly journals An In Vitro Coumarin-Antibiotic Combination Treatment of Pseudomonas aeruginosa Biofilms

2021 ◽  
Vol 16 (1) ◽  
pp. 1934578X2098774
Author(s):  
Jinpeng Zou ◽  
Yang Liu ◽  
Ruiwei Guo ◽  
Yu Tang ◽  
Zhengrong Shi ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Drug Resistance ◽  
Combination Treatment ◽  
Crude Extract ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Antibacterial Properties ◽  
Biofilm Growth ◽  
Antibiotic Combination

The drug resistance of Pseudomonas aeruginosa is a worldwide problem due to its great threat to human health. A crude extract of Angelica dahurica has been proved to have antibacterial properties, which suggested that it may be able to inhibit the biofilm formation of P. aeruginosa; initial exploration had shown that the crude extract could inhibit the growth of P. aeruginosa effectively. After the adaptive dose of coumarin was confirmed to be a potential treatment for the bacteria’s drug resistance, “coumarin-antibiotic combination treatments” (3 coumarins—simple coumarin, imperatorin, and isoimperatorin—combined with 2 antibiotics—ampicillin and ceftazidime) were examined to determine their capability to inhibit P. aeruginosa. The final results showed that (1) coumarin with either ampicillin or ceftazidime significantly inhibited the biofilm formation of P. aeruginosa; (2) coumarin could directly destroy mature biofilms; and (3) the combination treatment can synergistically enhance the inhibition of biofilm formation, which could significantly reduce the usage of antibiotics and bacterial resistance. To sum up, a coumarin-antibiotic combination treatment may be a potential way to inhibit the biofilm growth of P. aeruginosa and provides a reference for antibiotic resistance treatment.

A dual drug therapy for sunitinib resistant RCC: An in vitro analysis.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 340-340
Author(s):  
Jacob W. Greenberg ◽  
Hogyoung Kim ◽  
Ahmed A Moustafa ◽  
Pedro C. Barata ◽  
Asim Abdel-Mageed ◽  
...  
Keyword(s):  
Drug Resistance ◽  
T Cells ◽  
Cell Lines ◽  
Drug Combination ◽  
Kinase Inhibitors ◽  
Immunoblot Analysis ◽  
Tumor Burden ◽  
Colony Forming Units ◽  
Colony Forming Units Assay

340 Background: Over the last decade, medical treatment for metastatic renal cell carcinoma has made significant advances through the development of tyrosine kinase inhibitors (TKI) like sunitinib. However, of patients initiated on TKI therapy, 70% respond well while 30% are believed to be primarily resistant to treatment. Additionally, 30% of patients who initially respond to treatment gain secondary drug resistance and present with increased tumor burden. In this study, we seek to develop a combination therapy of Tipifarnib + Sunitinib to target exosome conferred drug resistance. Methods: 786-O, 786-0 Sunitinib Resistant (SR), and 293-T cells were cultured in RPMI 1640 medium supplemented with 10% fetal bovine serum, 2mM L-glutamine, and 1% penicillin/streptomycin (P/S). Exosomes were collected from conditioned media treated with Tipifarnib and isolated using differential ultracentrifugation. Exosomes were analyzed using the qNano IZON system. Colony forming units assay and Immunoblot analysis were used to further characterize or samples. Results: Exosomes collected from 786-O, 786-0 SR, and 293-T cells treated with 0.5 uM of Tipifarnib were compared using our qNANO IZON system. Exosome concentrations of all cell lines showed a decrease after Tipifarnib treatment. However, our 293-T cells showed a 16% decrease in exosome concentration while our 786-O and 786-0 SR lines displayed a 66% and 75% decrease respectively. To assess the pathway Tipifarnib used to decrease exosome concentrations, immunoblot assay was used after treating cells with 0, 0.1, 0.25, 0.5, 1 uM of tipifarnib. 293-T cells showed a dose dependent increase in ESCRT-dependent marker Alix and no change in either ESCRT-independent marker nSMase or trafficking marker Rab27a. Conversely, our 786-O and 786-0 SR cell lines showed a decrease in all 3 markers: Alix, nSMase, and Rab27a. Furthermore, a colony forming units assay was used to assess the drug combination of tipifarnib + sunitinib ability to alter cell growth. After 48hr, 293-T cell showed no decrease in colony forming units when compared to DMSO control. Our drug combination showed a synergistic ability to decrease colony forming units in the RCC 786-O cell line. 786-O SR cells were resistant to sunitinib treatment, showing comparable CFUs to DMSO control. When treated with the combination of sunitinib and tipifarnib, CTUs of 786-0 SR cells dropped significantly when compared to unaccompanied sunitinib and tipifarnib treatments. Conclusions: Tipifarnib has the ability to attenuate both the exosome ESCRT–dependent and –independent pathways. Our study also showed that when used injunction with sunitinib, tipifarnib is effective at decreasing cell proliferation. This drug combination is also pre-clinically useful in sunitinib resistance cancer cells. We believe this drug combination to be efficacious at decreasing tumor burden through blocking exosome biogenesis and secretion.

scholarly journals Potential Combination Drug Therapy to Prevent Redox Stress and Mitophagy Dysregulation in Retinal Müller Cells under High Glucose Conditions: Implications for Diabetic Retinopathy

Diseases ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 91
Author(s):  
Lalit Pukhrambam Singh ◽  
Takhellambam S. Devi
Keyword(s):  
Transcription Factor ◽  
Diabetic Retinopathy ◽  
Drug Treatment ◽  
Combination Treatment ◽  
High Glucose ◽  
Drug Combination ◽  
Redox Stress ◽  
Combination Drug ◽  
Mitochondrial Stress

Chronic hyperglycemia-induced thioredoxin-interacting protein (TXNIP) expression, associated oxidative/nitrosative stress (ROS/RNS), and mitochondrial dysfunction play critical roles in the etiology of diabetic retinopathy (DR). However, there is no effective drug treatment to prevent or slow down the progression of DR. The purpose of this study is to examine if a combination drug treatment targeting TXNIP and the mitochondria-lysosome pathway prevents high glucose-induced mitochondrial stress and mitophagic flux in retinal Müller glial cells in culture, relevant to DR. We show that diabetes induces TXNIP expression, redox stress, and Müller glia activation (gliosis) in rat retinas when compared to non-diabetic rat retinas. Furthermore, high glucose (HG, 25 mM versus low glucose, LG 5.5 mM) also induces TXNIP expression and mitochondrial stress in a rat retinal Müller cell line, rMC1, in in vitro cultures. Additionally, we develop a mitochondria-targeted mCherry and EGFP probe tagged with two tandem COX8a mitochondrial target sequences (adenovirus-CMV-2×mt8a-CG) to examine mitophagic flux in rMC1. A triple drug combination treatment was applied using TXNIP-IN1 (which inhibits TXNIP interaction with thioredoxin), Mito-Tempo (mitochondrial anti-oxidant), and ML-SA1 (lysosome targeted activator of transient calcium channel MCOLN1/TRPML1 and of transcription factor TFEB) to study the mitochondrial–lysosomal axis dysregulation. We found that HG induces TXNIP expression, redox stress, and mitophagic flux in rMC1 versus LG. Treatment with the triple drug combination prevents mitophagic flux and restores transcription factor TFEB and PGC1α nuclear localization under HG, which is critical for lysosome biosynthesis and mitogenesis, respectively. Our results demonstrate that 2×mt8a-CG is a suitable probe for monitoring mitophagic flux, both in live and fixed cells in in vitro experiments, which may also be applicable to in vivo animal studies, and that the triple drug combination treatment has the potential for preventing retinal injury and disease progression in diabetes.

scholarly journals CDK5/CAMK2-DRP1-AMPK-Mediated Mitochondrial Fission is Required for Imatinib Resistance of CML Cells

2020 ◽  
Author(s):  
Ziyuan Lu ◽  
Jiaming Tang ◽  
Yuling Li ◽  
Guohua Liang ◽  
Xiaoyun Chen ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Combination Treatment ◽  
Mitochondrial Respiration ◽  
Kinase Inhibitors ◽  
Mitochondrial Fission ◽  
Detection Methods ◽  
Drug Resistant ◽  
Imatinib Resistance

Abstract Background: In chronic myeloid leukemia (CML), resistance to tyrosine kinase inhibitors (TKIs) is still a serious clinical challenge, especially in the context of multi-resistance BCR-ABL mutations, such as T315I. Increasing evidence has demonstrated that mitochondrial fission plays an important role in cancer stem cell maintenance and drug resistance. Therefore, as a vital fission-related protein, DRP1 serves as a novel target for cancer treatment. However, whether DRP1 inhibition could overcome imatinib resistance in CML remains unknown.Methods: We used bioinformatic analysis and a confocal microscopy experimental approach to investigate whether mitochondrial fission could be involved in drug resistance in CML. Next, we applied biological and metabolic detection methods to reveal the roles of DPR1 in autophagy, apoptosis, and mitochondrial respiration in CML cells and determine whether coupling imatinib with DRP1 inhibition has a synergetic anti-leukemic effect on both drug-sensitive and drug-resistant CML cells. Results: Resistant CML cells displayed fragmented mitochondria and were accompanied by overexpression of active DRP1 compared with their sensitive counterparts. Furthermore, blocking DRP1 decreased mitochondrial respiration via the CDK5/CAMK2-DRP1-AMPK signaling pathway. Additionally, DRP1 inhibition perturbed the balance between mitochondrial-dependent apoptosis and autophagy, which led to cell death. Finally, combination treatment with imatinib and DRP1 inhibition exhibited a synergetic anti-leukemic effect on both drug-sensitive and drug-resistant CML cells (including CML cells carrying T315I mutation) in in vitro or in vivo experiments.Conclusions: Combination treatment with imatinib and DRP1 inhibition may represent a promising strategy to overcome CML drug resistance.

scholarly journals IL-4 Mediated Upregulation of AMPK/SIRT1/PGC-1α Signalling Pathway Is Bypassed By Mitochondrial Complex I Downregulation By NAMPT Inhibition in Venetoclax and Ibrutinib Treated CLL Cells

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2616-2616
Author(s):  
Subir Roy Chowdhury ◽  
Cheryl Peltier ◽  
Eileen M. McMillan-Ward ◽  
Ryan Saleh ◽  
Tricia Choquette ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cell Viability ◽  
B Cell ◽  
Combination Treatment ◽  
Mitochondrial Respiration ◽  
Drug Combination ◽  
Complex I ◽  
Single Agent ◽  
Respiration Rates

Abstract Introduction: Chronic lymphocytic leukemia (CLL) is one of the most common types of leukemia in adults. Despite significant improvement in the treatment of CLL, drug resistance is emerging when using the single agents ibrutinib or venetoclax. To achieve greater depth of response, combination treatments are being used to eradicate disease. Altered mitochondrial metabolism is a key factor in CLL survival. In order to gain insights into the underlying biology of a promising drug combination treatment, we investigated the combination of venetoclax and ibrutinib on mitochondrial function as well as the B-cell receptor (BCR), apoptotic and adenosine monophosphate activated protein kinase /silent information regulator 1 / peroxisome proliferator-activated receptor-coactivator-1α (AMPK/SIRT1/PGC-1α) signaling pathways in CLL cells. We also evaluated a proposed mechanism of resistance using interleukin-4 (IL-4) to demonstrate the role of a nicotinamide phosphoribosyltransferase (NAMPT) specific inhibitor, FK866, in order to overcome resistance in vitro. Methods: Freshly isolated primary B-cells from CLL patients were treated with venetoclax, ibrutinib or their combination in a dose- and -time responsive fashion. CLL cells were also treated with IL-4 and FK866 in the presence or the absence of the combination treatment. Flow cytometry (Novocyte) was used to assess cell viability, mitochondrial membrane potential (MMP) and reactive oxygen species (ROS). Mitochondrial respiration rates and specific substrate-dependent respiration of individual complexes of the respiratory chain were measured by respirometry (Orobooros O2k oxygraph) and ATP levels by luminometry (Lmax Luminometer, Molecular Devices). Cellular, mitochondrial, and lysosomal morphology was evaluated by Philips CM10 electron microscope and Olympus BX51 fluorescent microscope. Changes in protein levels of signaling pathways were detected by immunoblotting. Results: Each single agent venetoclax or ibrutinib reduced mitochondrial respiration profiles in CLL cells in vitro. The combined effect of these drugs on the respiration profiles, ATP, MMP, ROS and cell viability was more profound than with each agent alone. Proteins involved in 1. BCR [Bruton's tyrosine kinase (BTK); serine/threonine-specific protein kinase (AKT); phospholipase Cɣ2 (PLCɣ2) and extracellular signal-regulated kinase (ERK)], 2. Apoptotic B-cell lymphoma 2 (BCL-2); myeloid cell leukemia-1 (MCL-1) and 3. AMPK/SIRT1/PGC-1α signaling in the venetoclax and ibrutinib combination treated samples were significantly reduced when compared to DMSO and each single agent. AMPK/SIRT1/PGC-1α regulated transcription factors responsible for mitochondrial biogenesis [nuclear respiratory factor (NRF1 and NRF2)] and mitochondrial dynamics related proteins [mitofusin 2 (MFN2) and dynamin-related protein 1 (DRP1)] were preferentially downregulated by the combination treatment. These effects are seen in the morphological changes, as visualized by transmission electron microscopy demonstrating swelling of mitochondria (venetoclax) and vacuole formation (ibrutinib) in addition to the formation of multi-vesicular bodies in the combination. We also validated the impact of the mitochondria and lysosomes using immunofluorescence. In the presence of IL-4 (a secreted cytokine used to activate the BCR), the effects of the combination were negated by the addition of the NAMPT inhibitor, FK866. FK866 also preferentially decreased mitochondrial respiration rates in the presence of Complex I specific substrates and sustained this inhibition in all FK866 containing conditions regardless of IL-4. Conclusions: The combined effect of venetoclax and ibrutinib to target mitochondrial metabolism via the AMPK/SIRT1/PGC-1α signaling pathway provides a rationale for this drug combination treatment. The use of IL-4 identifies a potential path of resistance that can be overcome by NAMPT inhibition by directly targeting Complex I of the electron transport chain of the mitochondria. Disclosures No relevant conflicts of interest to declare.

Are Carbonic Anhydrases Suitable Targets to Fight Protozoan Parasitic Diseases?

2019 ◽  
Vol 25 (39) ◽  
pp. 5266-5278 ◽  
Author(s):  
Katia D'Ambrosio ◽  
Claudiu T. Supuran ◽  
Giuseppina De Simone
Keyword(s):  
Drug Resistance ◽  
Animal Models ◽  
Carbonic Anhydrase ◽  
Drug Target ◽  
Treatment Options ◽  
Parasitic Diseases ◽  
Carbonic Anhydrases ◽  
Extensive Drug Resistance ◽  
Protozoan Infections

Protozoans belonging to Plasmodium, Leishmania and Trypanosoma genera provoke widespread parasitic diseases with few treatment options and many of the clinically used drugs experiencing an extensive drug resistance phenomenon. In the last several years, the metalloenzyme Carbonic Anhydrase (CA, EC 4.2.1.1) was cloned and characterized in the genome of these protozoa, with the aim to search for a new drug target for fighting malaria, leishmaniasis and Chagas disease. P. falciparum encodes for a CA (PfCA) belonging to a novel genetic family, the η-CA class, L. donovani chagasi for a β-CA (LdcCA), whereas T. cruzi genome contains an α-CA (TcCA). These three enzymes were characterized in detail and a number of in vitro potent and selective inhibitors belonging to the sulfonamide, thiol, dithiocarbamate and hydroxamate classes were discovered. Some of these inhibitors were also effective in cell cultures and animal models of protozoan infections, making them of considerable interest for the development of new antiprotozoan drugs with a novel mechanism of action.

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