scholarly journals Application of Gene-Directed Enzyme Prodrug Therapy in Cancer Treatment

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Cindy Yeoh Shin Ly ◽  
Anil Philip Kunnath
Keyword(s):  
Tumor Cells ◽  
Tumor Regression ◽  
Cytosine Deaminase ◽  
Therapeutic Index ◽  
Specific Gene ◽  
Enzyme Prodrug Therapy ◽  
E Coli ◽  
Carboxypeptidase G2 ◽  
High Concentrations ◽  
Simplex Virus

Gene-directed enzyme prodrug therapy (GDEPT) is an advanced cancer therapy that has potential use against localized and metastasized cancer. This strategy aims to improve the limitations of chemotherapy and existing cancer treatments by specific gene delivery, which allows the conversion of systemically administered nontoxic prodrugs to active chemotherapeutic drugs inside the target tumor cells, thereby resulting in a significant therapeutic index by introducing high concentrations of cytotoxic compounds to the tumor cells while limiting the systemic toxicity. The main attraction of GDEPT is by expanding the toxicity to adjacent non-expressing target cancer cells through local and distal bystander effects, leading to tumor regression. This review focused on the application of the six main GDEPT systems for treating cancer, including herpes simplex virus thymidine kinase (HSV-TK) with ganciclovir (GCV), cytosine deaminase (CD) from bacteria or yeast with 5-fluorocytosine (5-FC), E. coli nitroreductase (NfsB) with 5-(aziridin-1-yl)-2,4- initrobenzamide (CB1954), hepatic cytochrome P4l50 (CYP450) with cyclophosphamide (CPA), purine nucleoside phosphorylase (PNP) from E. coli with 6-methylpurine deoxyriboside (MEP), and bacterial carboxypeptidase G2 (CPG2) with 4-[(2-chloroethyl)(2-mesloxyethyl)amino] benzoyl-L-glutamic acid (CMDA). In each system, the mechanism of action, clinical trials for the past decades, limitations, and areas that need improvement are discussed.

Microbial enzymes used in prodrug activation for cancer therapy: Insights and future perspectives

2020 ◽  
Vol 21 ◽  
Author(s):  
Rakhi Dhankhar ◽  
Anubhuti Kawatra ◽  
Aparajita Mohanty ◽  
Pooja Gulati
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Cytosine Deaminase ◽  
Therapeutic Index ◽  
Enzyme Prodrug Therapy ◽  
Prodrug Activation ◽  
Microbial Enzymes ◽  
High Productivity ◽  
Delivery Vector ◽  
Exogenous Enzymes ◽  
Activation Therapy

Abstract:: Enzyme prodrug therapy has gained momentum in the recent years due to their ability to improve therapeutic index (benefits versus toxic side-effects) and efficacy of chemotherapy in cancer treatment. Inactive prodrugs used in this system are converted into active anti-cancerous drugs by enzymes, specifically within the tumor cells. This therapy involves three components namely prodrug, enzyme and gene delivery vector. Past reports have clearly indicated that the choice of enzyme used, is the major determinant for the success of this therapy. Generally, enzymes from non-human sources are employed to avoid off-target toxicity. Exogenous enzymes also give a better control to the clinician regarding the calibration of treatment by site-specific initiation. Amongst these exo-enzymes, microbial enzymes are preferred due to their high productivity, stability and ease of manipulation. The present review focuses on the commonly used microbial enzymes particularly cytosine deaminase, nitroreductase, carboxypeptidase, purine nucleoside phosphorylase in prodrug activation therapy. Various aspects viz. source of the enzymes, types of cancer targeted, mode of action and efficacy of the enzyme/prodrug system, efficient vectors used and recent research developments of each of these enzymes are comprehensively elaborated. Further, the results of the clinical trials and various strategies to improve their clinical applicability are also discussed.

scholarly journals Prodrug suicide gene therapy for cancer targeted intracellular by mesenchymal stem cell exosomes

2018 ◽  
Author(s):  
Ursula Altanerova ◽  
Jana Jakubechova ◽  
Katarina Benejova ◽  
Petra Priscakova ◽  
Martin Pesta ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Fusion Gene ◽  
Cytosine Deaminase ◽  
Human Tumor ◽  
Suicide Gene ◽  
Tumor Cell Death ◽  
Kinase Gene ◽  
New Class ◽  
Simplex Virus

AbstractHuman tumor trophic mesenchymal stem cells (MSCs) isolated from various tissues and MSCs engineered to express the yeast cytosine deaminase::uracil phosphoribosyl transferase suicide fusion gene (yCD::UPRT‒MSCs) released exosomes in conditional medium (CM). Exosomes from all tissue specific yCD::UPRT‒MSCs contained mRNA of the suicide gene in the exosome’s cargo. When the CM was applied to tumor cells, the exosomes were internalized by recipient tumor cells and in the presence of the prodrug 5‒fluorocytosine (5‒FC) effectively triggered dose‒dependent tumor cell death by endocytosed exosomes via an intracellular conversion of the prodrug 5‒FC to 5‒fluorouracil. Exosomes were found to be responsible for the tumor inhibitory activity. MSCs transduced with the Herpes simplex virus thymidine kinase gene released exosomes causing death of tumor cells in the presence of ganciclovir. The presence of microRNAs in exosomes produced from naive MSCs and corresponding transgene transduced MSCs did not differ significantly. microRNAs from yCD::UPRT‒MSCs were not associated with therapeutic effect. MSC suicide gene exosomes represent a new class of tumor cell targeting drug acting intracellular with curative potential.

Hygienic risk assessment by monitoring pathogens in municipal sewage

2002 ◽  
Vol 2 (3) ◽  
pp. 23-28 ◽  
Author(s):  
C.-H. von Bonsdorff ◽  
L. Maunula ◽  
R.M. Niemi ◽  
R. Rimhanen-Finne ◽  
M.-L. Hänninen ◽  
...  
Keyword(s):  
Enteric Viruses ◽  
Detection Methods ◽  
Municipal Sewage ◽  
Small Community ◽  
E Coli ◽  
Cryptosporidium Oocysts ◽  
High Concentrations ◽  
One Year ◽  
Enteric Protozoa ◽  
Day Care Centre

The purpose of this study was to monitor the levels of human enteric viruses and enteric protozoa and to relate their presence to the microbes used as hygienic quality indicators in domestic sewage from a small community in Finland during a period of one year. Genome-based sensitive detection methods for the pathogens selected (astro- and Norwalk-like viruses, Giardia and Cryptosporidium) have become available only recently and thus no earlier data was available. The effluent sewage is delivered into a river that serves as raw water for a larger town and the pathogens therefore constitute a health risk. The results showed that all the monitored pathogens could be detected, and that enteric viruses were present at considerable concentrations in sewage. High concentrations of astrovirus in raw sewage were observed during a diarrhea epidemic in the local day-care centre. The presence of viruses did not correlate with the monitored bacterial indicators of faecal contamination (coliforms, E. coli and enterococci) or with bacteriophages (somatic coliphages, F-specific RNA phages and B. fragilis phages). Giardia cysts and Cryptosporidium oocysts were detected from one sample (1/10) each.

Use of gene probes for the detection of quiescent enteric bacteria in marine and fresh waters

1995 ◽  
Vol 31 (5-6) ◽  
pp. 291-298
Author(s):  
Sally A. Anderson ◽  
Gillian D. Lewis ◽  
Michael N. Pearson
Keyword(s):  
Membrane Filtration ◽  
Enteric Bacteria ◽  
Probe Method ◽  
Detection Methods ◽  
23S Rrna ◽  
Specific Gene ◽  
Gene Probe ◽  
Selective Media ◽  
Selective Enrichment ◽  
E Coli

Specific gene probe detection methods that utilise a non-selective culturing step were tested for the ability to recognise the presence of quiescent enteric bacteria (Escherichia coli and Enterococcus faecalis ) within illuminated freshwater and seawater microcosms. An E. coli specific uidA gene probe and a 23S rRNA oligonucleotide probe for Enterococci were compared with recoveries using membrane filtration and incubation on selective media (mTEC and mE respectively). From these microcosm experiments a greater initial detection (from 4 hours to 1 day) of E. coli and Ent. faecalis using gene probe methods was observed. Additionally, a comparison of E. coli direct viable counts (DVC) in sunlight exposed microcosms with recoveries by selective media and gene probe methods revealed a large number of viable non-culturable cells. This suggests that enumeration of E. coli by a gene probe method is limited by the replication of the bacteria during the initial non-selective enrichment step. The detection of stressed Ent. faecalis by the oligonucleotide gene probe method was significantly greater than recovery on selective mE agar, indicating an Enterococci non-growth phase.

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

2019 ◽  
Vol 22 (5) ◽  
pp. 346-354
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
Reporter System ◽  
E Coli ◽  
Starting Point ◽  
High Concentrations ◽  
Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

scholarly journals Bi-Functional Radiotheranostics of 188Re-Liposome-Fcy-hEGF for Radio- and Chemo-Therapy of EGFR-Overexpressing Cancer Cells

2021 ◽  
Vol 22 (4) ◽  
pp. 1902 ◽  
Author(s):  
Yi-Shu Huang ◽  
Wei-Chuan Hsu ◽  
Chien-Hong Lin ◽  
Sheng-Nan Lo ◽  
Chu-Nian Cheng ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Cytotoxic Effect ◽  
Cytosine Deaminase ◽  
Growth Factor Receptor ◽  
Size Exclusion ◽  
Specific Therapy ◽  
Egfr Expression ◽  
Epidermal Growth

Epidermal growth factor receptor (EGFR) specific therapeutics is of great importance in cancer treatment. Fcy-hEGF fusion protein, composed of yeast cytosine deaminase (Fcy) and human EGF (hEGF), is capable of binding to EGFR and enzymatically convert 5-fluorocytosine (5-FC) to 1000-fold toxic 5-fluorocuracil (5-FU), thereby inhibiting the growth of EGFR-expressing tumor cells. To develop EGFR-specific therapy, 188Re-liposome-Fcy-hEGF was constructed by insertion of Fcy-hEGF fusion protein onto the surface of liposomes encapsulating of 188Re. Western blotting, MALDI-TOF, column size exclusion and flow cytometry were used to confirm the conjugation and bio-activity of 188Re-liposome-Fcy-hEGF. Cell lines with EGFR expression were subjected to treat with 188Re-liposome-Fcy-hEGF/5-FC in the presence of 5-FC. The 188Re-liposome-Fcy-hEGF/5-FC revealed a better cytotoxic effect for cancer cells than the treatment of liposome-Fcy-hEGF/5-FC or 188Re-liposome-Fcy-hEGF alone. The therapeutics has radio- and chemo-toxicity simultaneously and specifically target to EGFR-expression tumor cells, thereby achieving synergistic anticancer activity.

scholarly journals Gene-Directed Enzyme Prodrug Therapy by Dendrimer-Like Mesoporous Silica Nanoparticles against Tumor Cells

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1298
Author(s):  
Vicente Candela-Noguera ◽  
Gema Vivo-Llorca ◽  
Borja Díaz de Greñu ◽  
María Alfonso ◽  
Elena Aznar ◽  
...  
Keyword(s):  
Cell Death ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Tumor Cells ◽  
Mesoporous Silica Nanoparticles ◽  
Combined Treatment ◽  
Bond Rupture ◽  
Enzyme Prodrug Therapy ◽  
Bacterial Gene ◽  
Reducing Environment

We report herein a gene-directed enzyme prodrug therapy (GDEPT) system using gated mesoporous silica nanoparticles (MSNs) in an attempt to combine the reduction of side effects characteristic of GDEPT with improved pharmacokinetics promoted by gated MSNs. The system consists of the transfection of cancer cells with a plasmid controlled by the cytomegalovirus promoter, which promotes β-galactosidase (β-gal) expression from the bacterial gene lacZ (CMV-lacZ). Moreover, dendrimer-like mesoporous silica nanoparticles (DMSNs) are loaded with the prodrug doxorubicin modified with a galactose unit through a self-immolative group (DOXO-Gal) and modified with a disulfide-containing polyethyleneglycol gatekeeper. Once in tumor cells, the reducing environment induces disulfide bond rupture in the gatekeeper with the subsequent DOXO-Gal delivery, which is enzymatically converted by β-gal into the cytotoxic doxorubicin drug, causing cell death. The combined treatment of the pair enzyme/DMSNs-prodrug are more effective in killing cells than the free prodrug DOXO-Gal alone in cells transfected with β-gal.

scholarly journals Anthracycline-induced cytotoxicity in the GL261 glioma model system

2021 ◽  
Author(s):  
Amber M. Tavener ◽  
Megan C. Phelps ◽  
Richard L. Daniels
Keyword(s):  
Cell Viability ◽  
Tumor Cells ◽  
Flow Cytometric Analysis ◽  
Annexin V ◽  
Chemotherapeutic Agents ◽  
Cytotoxic Effects ◽  
High Concentrations ◽  
Induced Apoptosis ◽  
Dose Dependent ◽  
Gl261 Glioma

AbstractGlioblastoma (GBM) is a lethal astrocyte-derived tumor that is currently treated with a multi-modal approach of surgical resection, radiotherapy, and temozolomide-based chemotherapy. Alternatives to current therapies are urgently needed as its prognosis remains poor. Anthracyclines are a class of compounds that show great potential as GBM chemotherapeutic agents and are widely used to treat solid tumors outside the central nervous system. Here we investigate the cytotoxic effects of doxorubicin and other anthracyclines on GL261 glioma tumor cells in anticipation of novel anthracycline-based CNS therapies. Three methods were used to quantify dose-dependent effects of anthracyclines on adherent GL261 tumor cells, a murine cell-based model of GBM. MTT assays quantified anthracycline effects on cell viability, comet assays examined doxorubicin genotoxicity, and flow cytometry with Annexin V/PI staining characterized doxorubicin-induced apoptosis and necrosis. Dose-dependent reductions in GL261 cell viability were found in cells treated with doxorubicin (EC50 = 4.9 μM), epirubicin (EC50 = 5.9 μM), and idarubicin (EC50 = 4.4 μM). Comet assays showed DNA damage following doxorubicin treatments, peaking at concentrations of 1.0 μM and declining after 25 μM. Lastly, flow cytometric analysis of doxorubicin-treated cells showed dose-dependent induction of apoptosis (EC50 = 5.2 μM). Together, these results characterized the cytotoxic effects of anthracyclines on GL261 glioma cells. We found dose-dependent apoptotic induction; however at high concentrations we find that cell death is likely necrotic. Our results support the continued exploration of anthracyclines as compounds with significant potential for improved GBM treatments.

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