scholarly journals Repurposing cytarabine for treating primary effusion lymphoma by targeting KSHV latent and lytic replications

2018 ◽  
Author(s):  
Marion Gruffaz ◽  
Shenghua Zhou ◽  
Karthik Vasan ◽  
Teresa Rushing ◽  
Qing Liu Michael ◽  
...  
Keyword(s):  
Mouse Model ◽  
High Throughput ◽  
High Throughput Screening ◽  
Therapeutic Agent ◽  
Potent Inhibitor ◽  
Primary Effusion Lymphoma ◽  
Viral Dna ◽  
Dna And Rna ◽  
Virion Production ◽  
Novel Therapeutic

AbstractOncogenic Kaposi’s sarcoma-associated herpesvirus (KSHV) is etiologically linked to primary effusion lymphoma (PEL), an aggressive and non-treatable malignancy commonly found in AIDS patients. In this study, we performed a high throughput screening of 3,731 characterized compounds, and identified cytarabine approved by FDA for treating numerous types of cancer as a potent inhibitor of KSHV-induced PEL. We showed the high efficacy of cytarabine in the growth inhibition of various PEL cells by inducing cell cycle arrest and apoptosis. Cytarabine inhibited host DNA and RNA syntheses and therefore induced cellular cytotoxicity. Furthermore, cytarabine inhibited viral DNA and RNA syntheses and induced the the rapid degradation of KSHV major latent protein LANA, leading to the suppression of KSHV latent replication. Importantly, cytarabine effectively inhibited active KSHV replication and virion production in PEL cells. Finally, cytarabine treatments not only effectively inhibited the initiation and progression of PEL tumors, but also induced regression of grown PEL tumors in a xenograft mouse model. Together, our study has identified cytarabine as novel therapeutic agent for treating PEL as well as eliminating KSHV persistent infection.ImportancePrimary effusion lymphoma is an aggressive malignancy caused by Kaposi’s sarcoma-associated herpesvirus. The outcome of primary effusion lymphoma is dismal without specific treatment. Through a high throughput screening of characterized compounds, we identified a FDA-approved compound cytarabine as a potent inhibitor of primary effusion lymphoma. We showed that cytarabine induced regression of PEL tumors in a xenograft mouse model. Cytarabine inhibited host and viral DNA and RNA syntheses, resulting in the induction of cytotoxicity. Of interest, cytarabine induced the degradation of KSHV major latent protein LANA, hence suppressing KSHV latent replication, which is required for PEL survival. Furthermore, cytarabine inhibited KSHV lytic replication program, preventing virion production. Our findings identified cytarabine as novel therapeutic agent for treating PEL as well as for eliminating KSHV persistent infection. Since cytarabine is already approved by the FDA, it might be an ideal candidate for repurposing for PEL therapy and for further evaluation in advanced clinical trials.

scholarly journals Repurposing Cytarabine for Treating Primary Effusion Lymphoma by Targeting Kaposi’s Sarcoma-Associated Herpesvirus Latent and Lytic Replications

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Marion Gruffaz ◽  
Shenghua Zhou ◽  
Karthik Vasan ◽  
Teresa Rushing ◽  
Qing Liu Michael ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Kaposi's Sarcoma ◽  
Therapeutic Agent ◽  
Potent Inhibitor ◽  
Primary Effusion Lymphoma ◽  
Kaposi’S Sarcoma ◽  
Dna And Rna ◽  
Virion Production ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Oncogenic Kaposi’s sarcoma-associated herpesvirus (KSHV) is etiologically linked to primary effusion lymphoma (PEL), an aggressive and nontreatable malignancy commonly found in AIDS patients. In this study, we performed a high-throughput screening of 3,731 characterized compounds and identified cytarabine, approved by the FDA for treating numerous types of cancer, as a potent inhibitor of KSHV-induced PEL. We showed the high efficacy of cytarabine in the growth inhibition of various PEL cells by inducing cell cycle arrest and apoptosis. Cytarabine inhibited host DNA and RNA syntheses and therefore induced cellular cytotoxicity. Furthermore, cytarabine inhibited viral DNA and RNA syntheses and induced the rapid degradation of KSHV major latent protein LANA (latency-associated nuclear antigen), leading to the suppression of KSHV latent replication. Importantly, cytarabine effectively inhibited active KSHV replication and virion production in PEL cells. Finally, cytarabine treatments not only effectively inhibited the initiation and progression of PEL tumors but also induced regression of grown PEL tumors in a xenograft mouse model. Altogether, our study has identified cytarabine as a novel therapeutic agent for treating PEL as well as eliminating KSHV persistent infection. IMPORTANCE Primary effusion lymphoma is an aggressive malignancy caused by Kaposi’s sarcoma-associated herpesvirus. The outcome of primary effusion lymphoma is dismal without specific treatment. Through a high-throughput screening of characterized compounds, we identified an FDA-approved compound, cytarabine, as a potent inhibitor of primary effusion lymphoma. We showed that cytarabine induced regression of PEL tumors in a xenograft mouse model. Cytarabine inhibited host and viral DNA and RNA syntheses, resulting in the induction of cytotoxicity. Of interest, cytarabine induced the degradation of KSHV major latent protein LANA, hence suppressing KSHV latent replication, which is required for PEL cell survival. Furthermore, cytarabine inhibited KSHV lytic replication program, preventing virion production. Our findings identified cytarabine as a novel therapeutic agent for treating PEL as well as for eliminating KSHV persistent infection. Since cytarabine is already approved by the FDA, it might be an ideal candidate for repurposing for PEL therapy and for further evaluation in advanced clinical trials.

scholarly journals Evaluation of a System to Screen for Stimulators of Non-Specific DNA Nicking by HIV-1 Integrase: Application to a Library of 50,000 Compounds

2011 ◽  
Vol 22 (2) ◽  
pp. 67-74 ◽  
Author(s):  
Malgorzata Sudol ◽  
Jennifer L Fritz ◽  
Melissa Tran ◽  
Gavin P Robertson ◽  
Julie B Ealy ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Solution Phase ◽  
The Novel ◽  
Endonuclease Activity ◽  
Viral Dna ◽  
Hit Rate ◽  
Dna Nicking ◽  
Hiv 1 ◽  
Stimulation Of

Background: In addition to activities needed to catalyse integration, retroviral integrases exhibit non-specific endonuclease activity that is enhanced by certain small compounds, suggesting that integrase could be stimulated to damage viral DNA before integration occurs. Methods: A non-radioactive, plate-based, solution phase, fluorescence assay was used to screen a library of 50,080 drug-like chemicals for stimulation of non-specific DNA nicking by HIV-1 integrase. Results: A semi-automated workflow was established and primary hits were readily identified from a graphic output. Overall, 0.6% of the chemicals caused a large increase in fluorescence (the primary hit rate) without also having visible colour that could have artifactually caused this result. None of the potential stimulators from this moderate-size library, however, passed a secondary test that included an inactive integrase mutant that assessed whether the increased fluorescence depended on the endonuclease activity of integrase. Conclusions: This first attempt at identifying integrase stimulator compounds establishes the necessary logistics and workflow required. The results from this study should encourage larger scale high-throughput screening to advance the novel antiviral strategy of stimulating integrase to damage retroviral DNA.

scholarly journals A high-throughput screening method for evolving a demethylase enzyme with improved and new functionalities

2020 ◽  
Author(s):  
Yuru Wang ◽  
Christopher D Katanski ◽  
Christopher Watkins ◽  
Jessica N Pan ◽  
Qing Dai ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Screening Method ◽  
Targeted Mutagenesis ◽  
Rna Repair ◽  
Dna And Rna ◽  
Modified Dna ◽  
Dna Substrates ◽  
Trna Sequencing

Abstract AlkB is a DNA/RNA repair enzyme that removes base alkylations such as N1-methyladenosine (m1A) or N3-methylcytosine (m3C) from DNA and RNA. The AlkB enzyme has been used as a critical tool to facilitate tRNA sequencing and identification of mRNA modifications. As a tool, AlkB mutants with better reactivity and new functionalities are highly desired; however, previous identification of such AlkB mutants was based on the classical approach of targeted mutagenesis. Here, we introduce a high-throughput screening method to evaluate libraries of AlkB variants for demethylation activity on RNA and DNA substrates. This method is based on a fluorogenic RNA aptamer with an internal modified RNA/DNA residue which can block reverse transcription or introduce mutations leading to loss of fluorescence inherent in the cDNA product. Demethylation by an AlkB variant eliminates the blockage or mutation thereby restores the fluorescence signals. We applied our screening method to sites D135 and R210 in the Escherichia coli AlkB protein and identified a variant with improved activity beyond a previously known hyperactive mutant toward N1-methylguanosine (m1G) in RNA. We also applied our method to O6-methylguanosine (O6mG) modified DNA substrates and identified candidate AlkB variants with demethylating activity. Our study provides a high-throughput screening method for in vitro evolution of any demethylase enzyme.

Use of a high-throughput screen to identify Leptospira mutants unable to colonize the carrier host or cause disease in the acute model of infection

2013 ◽  
Vol 62 (10) ◽  
pp. 1601-1608 ◽  
Author(s):  
Renee A. Marcsisin ◽  
Thanatchaporn Bartpho ◽  
Dieter M. Bulach ◽  
Amporn Srikram ◽  
Rasana W. Sermswan ◽  
...  
Keyword(s):  
Mouse Model ◽  
Virulence Factors ◽  
High Throughput ◽  
High Throughput Screening ◽  
Acute Infection ◽  
Screening Method ◽  
Hamster Model ◽  
Genes Encoding ◽  
Transposon Mutants

The molecular basis for leptospirosis infection and colonization remains poorly understood, with no efficient methods available for screening libraries of mutants for attenuation. We analysed the attenuation of leptospiral transposon mutants in vivo using a high-throughput method by infecting animals with pooled sets of transposon mutants. A total of 95 mutants was analysed by this method in the hamster model of acute infection, and one mutant was identified as attenuated (M1233, lb058 mutant). All virulence factors identified in Leptospira to date have been characterized in the acute model of infection, neglecting the carrier host. To address this, a BALB/c mouse colonization model was established. The lb058 mutant and two mutants defective in LPS synthesis were colonization deficient in the mouse model. By applying the high-throughput screening method, a further five colonization-deficient mutants were identified for the mouse model; these included two mutants in genes encoding proteins with a predicted role in iron uptake (LB191/HbpA and LB194). Two attenuated mutants had transposon insertions in either la0589 or la2786 (encoding proteins of unknown function). The final attenuated mutant had an unexpected deletion of genes la0969–la0975 at the point of transposon insertion. This is the first description of defined, colonization-deficient mutants in a carrier host for Leptospira. These mutants were either not attenuated or only weakly attenuated in the hamster model of acute leptospirosis, thus illustrating that different factors that may be required in the carrier and acute models of leptospiral infection. High-throughput screening can reduce the number of animals used in virulence studies and increase the capacity to screen mutants for attenuation, thereby enhancing the likelihood of detecting unique virulence factors. A comparison of virulence factors required in the carrier and acute models of infection will help to unravel colonization and dissemination mechanisms of leptospirosis.

scholarly journals DDIS-28. A HIGH THROUGHPUT SCREENING PLATFORM TO IDENTIFY RADIOSENSITIZERS FOR DIPG

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi69-vi69
Author(s):  
Matt Clutter ◽  
Megan Romero ◽  
Oren Becher
Keyword(s):  
Clinical Trials ◽  
Mouse Model ◽  
High Throughput ◽  
High Throughput Screening ◽  
Animal Studies ◽  
Ex Vivo ◽  
Genetically Engineered ◽  
Clinical Activity ◽  
K27m Mutation ◽  
Genetically Engineered Mouse Model

Abstract Diffuse intrinsic pontine glioma (DIPG) is an incurable brainstem tumor and the leading cause of death in children with brain cancer. Despite numerous clinical trials, no drugs have been found to prolong survival for DIPG patients, suggesting an urgent need to test therapeutics in preclinical models more predictive of clinical activity. To address this gap, we developed a genetically engineered mouse model incorporating the Histone H3.3 K27M mutation, p53 deletion, and PDGFR-α amplification, which co-occur in up to 40% of human DIPG. Here we report the results of a drug screen to identify radiosensitizers of DIPG cells isolated from our mouse model and cultured ex vivo as neurospheres. Although previous clinical trials combining radiotherapy with radiosensitizing agents failed to benefit DIPG patients, they incorporated general radiosensitizers. We hypothesize that searching for radiosynergy using 3-dimensional neurospheres derived from genetically defined primary cell DIPG models will enhance our ability to prioritize clinically relevant radiosensitizers. To identify candidates, we developed high throughput radiation and imaging protocols to quantify the number, size, and viability of neurospheres following treatment. We screened 1,280 FDA-approved drugs and 1,600 molecules with a history of clinical use. Two mechanistic classes of compounds were identified that sensitized DIPG neurospheres to radiotherapy, both targeting epigenetic factors. An HDAC1/3 inhibitor along with several different BET bromodomain inhibitors increased cell death 2–3 fold beyond the effect of radiation with minimal activity from the compounds alone. In addition to optimizing the dosing and timing of these compounds for animal studies, we are investigating whether radiosensitization occurs in H3.3 wildtype neurospheres. In the current molecular era of cancer, genetic features like the H3.3 K27M mutation could present an opportunity to develop therapeutics that preferentially radiosensitize diseased cells relative to normal cells. Such “precision radiosensitizers” would advance radiotherapy by enhancing tumor-specific toxicity while sparing bystander cells.

scholarly journals A High-Throughput Screening Approach to Identify Therapeutics for the Treatment of Diamond-Blackfan Anaemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3859-3859
Author(s):  
Lorena Nunez Villacis ◽  
Sheren J Al-Obaidi ◽  
Piyush Madhamshettiwar ◽  
Nadine Hein ◽  
Jun Chen ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mouse Model ◽  
High Throughput ◽  
High Throughput Screening ◽  
P53 Protein ◽  
Bone Marrow Failure ◽  
Cell Number ◽  
Screening Approach ◽  
Erythroid Precursors ◽  
Diamond Blackfan Anaemia

Abstract Diamond-Blackfan Anaemia (DBA) is a rare blood cell aplasia that presents clinically at approximately 2-3 months of age and its main characteristic is reduced erythroid precursors in the bone marrow, i.e. anemia. Mutations in different ribosomal protein (RP) genes have been associated with DBA, with mutations in RPS19 accounting for 20-25% of all cases. It has been proposed that RPS19 deficiency causes perturbations in ribosome biogenesis, thus activation of the p53-dependent Nucleolar Surveillance Pathway (NSP). In this context free RPs (predominantly L5 and L11) in a complex with 5S rRNA sequester the E3 ubiquitin ligase murine double minute 2 (MDM2), leading to the accumulation of p53 and subsequent activation of its transcriptional targets mediating cell cycle arrest or apoptosis. In DBA, one of the molecular mechanisms impairing the proliferation and thus reducing the number of erythroid progenitors that can progress to mature red blood cells is an elevation of p53 protein mediating activation of the NSP. In order to identify potential therapeutics that could be repurposed to prevent the activation of NSP in DBA patients, we have screened compound libraries of clinically approved therapeutics to identify pathways implicated in the p53-dependent NSP due to RPS19 deficiency. We quantitated both cell number and the level of p53 expression, identifying compounds that can result in low and high expression of p53, the latter for potential use in cancer therapy. Using an RPS19 depleted A549 cell line as a model system, the screen successfully identified different therapeutic groups. In the DBA context, we were most interested in the compounds that reduced p53 and had no negative effect on cell number. A selection of 22 molecules were re-evaluated in vitro, again using RPS19 depleted A549 cells, through the quantification of p53 protein expression and densitometry analysis. From this, 10candidates were evaluated ex vivofor their effects on proliferation using bone marrow obtained from an inducible Rps19 knockdown (DBA) mouse model. While we are currently testing a number of compounds in vivo using the Rps19 DBA mouse model (as described), one of the compounds tested thus far has demonstrated a partial rescue of the cKit+ population, no changes in erythroid precursors but interestingly a reversal of the defect in the Granulocyte-Monocyte Progenitor (GMP) population. Impairment in lineage progression in the GMP compartment has also been reported to present in bone marrow failure Shwachman-Diamond Syndrome. We are currently evaluating the mechanism by which this drug is rescuing the c-Kit+ and GMP populations in these mice. In summary, our high-throughput screening approach and follow up studies have identified a suite of novel therapies that may be beneficial for repurposing for the treatment of bone marrow failure by increasing hematopoietic progenitor cells. We plan to evaluate this, and potentially other therapies, in a clinical trial with DBA patients. Disclosures Flygare: LU Holding: Patents & Royalties: Patent.

scholarly journals Identification of phosphorylase kinase as a novel therapeutic target through high-throughput screening for anti-angiogenesis compounds in zebrafish

Oncogene ◽  
2011 ◽  
Vol 31 (39) ◽  
pp. 4333-4342 ◽  
Author(s):  
S Camus ◽  
C Quevedo ◽  
S Menéndez ◽  
I Paramonov ◽  
P F W Stouten ◽  
...  
Keyword(s):  
High Throughput ◽  
Therapeutic Target ◽  
High Throughput Screening ◽  
Phosphorylase Kinase ◽  
Novel Therapeutic
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