Levels of APE1 Repair Gene and CLEC4M in Lung Cancer Patients Receiving Cisplatin Chemotherapy.

This study aimed to detect the levels of apurinic/apyrimidinic endonuclease 1 (APE1) gene expression and C-type lectin domain family 4 member M (CLEC4M) and their association with cisplatin chemotherapy in lung cancer patients. Overall, 105 individuals who attended the Al-Amal National Hospital for Cancer Management, Baghdad, Iraq, were enrolled in the study and divided into three equal groups. The groups included the patients newly diagnosed with lung cancer, cancer patients who received cisplatin, and the healthy control group. All study groups were subjected to the sampling of the venous blood for molecular analysis by real-time polymerase chain reaction (RT-PCR) to detect the APE1 gene and enzyme-linked immunosorbent assay (ELISA) for serological testing to measure the concentration of CLEC4M protein. Significantly, the values of both cancer groups were higher than those reported in the control group. The relative index revealed a significant difference in the mean fold change level of APE1 in the newly diagnosed group (3 fold) and cisplatin therapy patients group (2 fold), compared to the control group (P=0.005). No significant differences were detected between the two cancer groups in terms of fold change mean of expression, demographic characteristics, and cancer histological type. Regarding human CLEC4M protein level, cases receiving cisplatin (139.2±25.9) and newly diagnosed patients (331.0±38.1) had a highly significant difference with the control group (100.3±47.5, P<0.001). There was no significant difference between the concentration level of CLEC4M and all parameters in demographic characteristics and cancer histological type. This was the first study to demonstrate that higher expression levels of new APE1, CLEC4M, and glutathione, especially after chemotherapy, are beneficial as diagnostic and prognostic markers for resistance to platinum chemotherapy in Iraqi lung cancer patients.

Comparison of Intra-Familial Transmission of Influenza Virus From Index Patients Treated With Baloxavir Marboxil or Oseltamivir Using an Influenza Transmission Model and a Health Insurance Claims Database.

BACKGROUND: Influenza affects approximately a billion people globally, including > 10 million Japanese individuals every year. Baloxavir marboxil (baloxavir [BXM]; a selective cap-dependent endonuclease inhibitor) is approved for influenza treatment in Japan. We compared the incidence of intra-familial transmission of influenza between BXM and oseltamivir (OTV) treatments using a simulation model. METHODS: Using the JMDC Claims Database, we identified index case (IC) as the first family member diagnosed with influenza during the 2018-19 influenza season, and classified the families into BXM or OTV group per the drug dispensed to ICs. Using a novel influenza intra-familial infection model, we simulated the duration of influenza infection in ICs based on agent-specific virus shedding periods. Intra-familial infections were defined as non-IC family members infected during the agent-specific viral shedding period in ICs. The virus incubation periods in the non-IC family members were considered to exclude secondary infections from potentially external exposure. The primary endpoint was proportion of families with intra-familial infections. For between-group comparisons, we used a multivariate logistic regression model. RESULTS: The median proportion of families with intra-familial transmission was 9.57% and 19.35% in the BXM (N = 84 672) and OTV (N = 62 004) groups, respectively. The multivariate odds ratio of 1.73 (2.5th-97.5th percentiles, 1.68-1.77) indicated a substantially higher incidence of intra-familial infections in the OTV group versus the BXM group. Subgroup analyses by ICs' age category, virus type, and month of onset revealed similar trends favoring BXM. CONCLUSIONS: BXM treatment of ICs may contribute to a greater reduction in intra-familial influenza transmission than OTV treatment.

Predictive value of KRAS mutation and excision repair cross-complementing 1 (ERCC1) protein overexpression in patients with colorectal cancer administered FOLFOX regimen.

BACKGROUND: Recent studies have reported that KRAS mutational status is correlated with ERCC1 expression level. The purpose of this study was to determine the clinical significance of the KRAS mutation and ERCC1 overexpression status as predictive factors for resistance against oxaliplatin-based treatment. METHODS: We retrospectively analyzed clinicopathologic features, KRAS mutation status, and ERCC1 overexpression status in 386 patients with colorectal cancer (CRC) who underwent curative-intent surgery. Of these patients, 84 were administered the FOLFOX regimen as a first-line or adjuvant treatment. Disease-free survival and overall survival in groups separated by KRAS and ERCC1 statuses were analyzed. RESULTS: Wild-type KRAS and ERCC1 overexpression were observed in 25.5% of all patients. Among the 84 patients who were treated with the FOLFOX regimen, 73 patients were evaluated for KRAS and ERCC1 status. There were no significant differences in disease-free survival or overall survival in groups separated by KRAS mutation and ERCC1 expression status. Subgroup analysis of patients with wild-type KRAS showed that overall survival in the ERCC1 overexpression group was lower than that of patients in the ERCC1 underexpression group (p = 0.029); however, no significant difference was found in the mutant KRAS patient group (p = 0.671). CONCLUSIONS: Our results suggest that CRC with wild-type KRAS and ERCC1 overexpression might be associated with oxaliplatin resistance. When considering oxaliplatin-based chemotherapy, the status of both KRAS mutation and ERCC1 overexpression should be evaluated.

Engineering the Direct Repeat Sequence of crRNA for Optimization of FnCpf1-Mediated Genome Editing in Human Cells.

FnCpf1-mediated genome-editing technologies have enabled a broad range of research and medical applications. Recently, we reported that FnCpf1 possesses activity in human cells and recognizes a more compatible PAM (protospacer adjacent motif, 5'-KYTV-3'), compared with the other two commonly used Cpf1 enzymes (AsCpf1 and LbCpf1), which requires a 5'-TTTN-3' PAM. However, due to the efficiency and fidelity, FnCpf1-based clinical and basic applications remain a challenge. The direct repeat (DR) sequence is one of the key elements for FnCpf1-mediated genome editing. In principle, its engineering should influence the corresponding genome-editing activity and fidelity. Here we showed that the DR mutants [G(-9)A and U(-7)A] could modulate FnCpf1 performance in human cells, enabling enhancement of both genome-editing efficiency and fidelity. These newly identified features will facilitate the design and optimization of CRISPR-Cpf1-based genome-editing strategies.

Lymphopoiesis in transgenic mice over-expressing Artemis.

Artemis is a factor of the non-homologous end joining pathway involved in DNA double-strand break repair that has a critical role in V(D)J recombination. Mutations in DCLRE1C/ARTEMIS gene result in radiosensitive severe combined immunodeficiency in humans owing to a lack of mature T and B cells. Given the known drawbacks of allogeneic hematopoietic stem cell transplantation (HSCT), gene therapy appears as a promising alternative for these patients. However, the safety of an unregulated expression of Artemis has to be established. We developed a transgenic mouse model expressing human Artemis under the control of the strong CMV early enhancer/chicken beta actin promoter through knock-in at the ROSA26 locus to analyze this issue. Transgenic mice present a normal development, maturation and function of T and B cells with no signs of lymphopoietic malignancies for up to 15 months. These results suggest that the over-expression of Artemis in mice (up to 40 times) has no deleterious effects in early and mature lymphoid cells and support the safety of gene therapy as a possible curative treatment for Artemis-deficient patients.

Comparative Effects of Sunscreens Alone vs Sunscreens Plus DNA Repair Enzymes in Patients With Actinic Keratosis: Clinical and Molecular Findings from a 6-Month, Randomized, Clinical Study.

Recent experimental irradiation studies have shown that the addition of DNA repair enzymes (photolyase and endonuclease) to traditional sunscreens may reduce ultraviolet radiation (UVR)-induced molecular damage to the skin to a greater extent than sunscreens alone. In this 6-month, randomized, clinical study, we sought to compare the clinical and molecular effects of sunscreens plus DNA repair enzymes vs. those of traditional sunscreens alone in patients with actinic keratosis (AK). A total of 28 AK patients were randomized to topically apply sunscreens plus DNA repair enzymes (enzyme group; n = 14) or sunscreens alone (sunscreen group; n = 14) for 6 months. The main outcome measures included 1) hyperkeratosis, 2) field cancerization (as measured by fluorescence diagnostics using methylaminolaevulinate), and 3) levels of cyclobutane pyrimidine dimers (CPDs) in skin biopsies. Both regimens produced a significant reduction of hyperkeratosis at 6 months, with no difference between the two groups. Field cancerization was significantly reduced by both regimens, but the decrease observed in the enzyme group was significantly more pronounced than in the sunscreen group (P < 0.001). At 6 months, CPDs decreased by 61% in the enzyme group and by 35% in the sunscreen group compared with baseline values (P < 0.001). These findings indicate that, despite a similar effect on hyperkeratosis, the addition of DNA repair enzymes to sunscreens was more effective in reducing field cancerization and CPDs than sunscreens alone. Taken together, our findings indicate that sunscreens plus DNA repair enzymes may be superior to traditional sunscreens alone in reducing field cancerization and UVR-associated molecular signatures (CPDs) in AK patients, potentially preventing malignant transformation into invasive squamous cell carcinoma in a more efficient manner.

Shortening trinucleotide repeats using highly specific endonucleases: a possible approach to gene therapy?

Trinucleotide repeat expansions are involved in more than two dozen neurological and developmental disorders. Conventional therapeutic approaches aimed at regulating the expression level of affected genes, which rely on drugs, oligonucleotides, and/or transgenes, have met with only limited success so far. An alternative approach is to shorten repeats to non-pathological lengths using highly specific nucleases. Here, I review early experiments using meganucleases, zinc-finger nucleases (ZFN), and transcription-activator like effector nucleases (TALENs) to contract trinucleotide repeats, and discuss the possibility of using CRISPR-Cas nucleases to the same end. Although this is a nascent field, I explore the possibility of designing nucleases and effectively delivering them in the context of gene therapy.

RNA-guided endonuclease provides a therapeutic strategy to cure latent herpesviridae infection.

Latent viral infection is a persistent cause of human disease. Although standard antiviral therapies can suppress active viral replication, no existing treatment can effectively eradicate latent infection and therefore a cure is lacking for many prevalent viral diseases. The prokaryotic immune system clustered regularly interspaced short palindromic repeat (CRISPR)/Cas evolved as a natural response to phage infections, and we demonstrate here that the CRISPR/Cas9 system can be adapted for antiviral treatment in human cells by specifically targeting the genomes of latent viral infections. Patient-derived cells from a Burkitt's lymphoma with latent Epstein-Barr virus infection showed dramatic proliferation arrest and a concomitant decrease in viral load after exposure to a CRISPR/Cas9 vector targeted to the viral genome.

Biological and biomedical applications of engineered nucleases.

The development of engineered nucleases is the fruit of a new technological approach developed in the last two decades which has led to significant benefits on genome engineering, particularly on gene therapy. These applications enable efficient and specific genetic modifications via the induction of a double-strand break (DSB) in a specific genomic target sequence, followed by the homology-directed repair (HDR) or non-homologous end joining (NHEJ) pathways. In addition to the application on gene modification in cells and intact organisms, a number of recent papers have reported that this gene editing technology can be applied effectively to human diseases. With the promising data obtained using engineered endonucleases in gene therapy, it appears reasonable to expect that more diseases could be treated and even be cured in this new era of individualized medicine. This paper first brief introduces the development of engineered nucleases with a special emphasis on zinc-finger nucleases (ZFNs) and transcription activator-like effector (TALE) nucleases (TALENs), and then takes CCR5-based gene therapy as an example to discuss the therapeutic applications of engineered nucleases.

Targeted gene therapies: tools, applications, optimization.

Many devastating human diseases are caused by mutations in a single gene that prevent a somatic cell from carrying out its essential functions, or by genetic changes acquired as a result of infectious disease or in the course of cell transformation. Targeted gene therapies have emerged as potential strategies for treatment of such diseases. These therapies depend upon rare-cutting endonucleases to cleave at specific sites in or near disease genes. Targeted gene correction provides a template for homology-directed repair, enabling the cell's own repair pathways to erase the mutation and replace it with the correct sequence. Targeted gene disruption ablates the disease gene, disabling its function. Gene targeting can also promote other kinds of genome engineering, including mutation, insertion, or gene deletion. Targeted gene therapies present significant advantages compared to approaches to gene therapy that depend upon delivery of stably expressing transgenes. Recent progress has been fueled by advances in nuclease discovery and design, and by new strategies that maximize efficiency of targeting and minimize off-target damage. Future progress will build on deeper mechanistic understanding of critical factors and pathways.

Optimized TAL effector nucleases (TALENs) for use in treatment of sickle cell disease.

TAL effector nucleases (TALENs) represent a new class of artificial nucleases capable of cleaving long, specific target DNA sequences in vivo and are powerful tools for genome editing with potential therapeutic applications. Here we report a pair of custom-designed TALENs for targeted genetic correction of the sickle cell disease mutation in human cells, which represents an example of engineered TALENs capable of recognizing and cleaving a human disease-associated gene. By using a yeast reporter system, a systematic study was carried out to optimize TALEN architecture for maximal in vivo cleavage efficiency. In contrast to the previous reports, the engineered TALENs were capable of recognizing and cleaving target binding sites preceded by A, C or G. More importantly, the optimized TALENs efficiently cleaved a target sequence within the human ß-globin (HBB) gene associated with sickle cell disease and increased the efficiency of targeted gene repair by >1000-fold in human cells. In addition, these TALENs showed no detectable cytotoxicity. These results demonstrate the potential of optimized TALENs as a powerful genome editing tool for therapeutic applications.

Molecular scissors for in situ cellular repair.

The engineering of protein-DNA interactions in different protein scaffolds may provide "toolkits" to modify the genome. Homing endonucleases are powerful tools for genome manipulation through homologous recombination, as these enzymes possess a very low frequency of DNA cleavage in eukaryotic genomes due to their high specificity. Therefore, the combination of a precise "cutter" with the presence of a natural or modified homologous DNA donor provides a potentially useful means to modify the genome. However, the basis of protein-DNA recognition must be understood to generate tailored enzymes that target the DNA at sites of interest. The engineering of homing endonucleases and alternative scaffolds, such as zinc fingers or transcription activator-like effector domains, has demonstrated the potential of these approaches to create new specific instruments to target genes for inactivation or repair. Customized homing endonucleases targeting selected human genes can excise or correct regions of genes implicated in monogenic diseases, thereby representing important tools for intervention in eukaryotic genomes.

New approaches in HIV eradication research.

PURPOSE OF REVIEW: Despite the proven efficacy of highly active antiretroviral therapy in reducing mortality and morbidity of HIV infection, longer-term strategies are less well defined and there is renewed interest in HIV eradication. This review will describe the major obstacles that need to be overcome and the key new advances and strategies designed to achieve an HIV cure. RECENT FINDINGS: Characterization of the HIV viral reservoir over the past few years has led to a better understanding of which approaches might successfully lead to eradication. A number of approaches such as histone modification, immunotoxins, gene therapy and gene knockout strategies have resulted and have been explored initially in vitro. There has been progression from both laboratory and animal model studies, and clinical trials are now underway using new approaches such as histone deacetylase inhibitors and zinc finger nucleases. SUMMARY: Although there is currently no cure for HIV infection, there has been a resurgence of interest in the field with the development of a number of potential new approaches, some of which have entered clinical trials.

Plant ribonucleases and nucleases as antiproliferative agens targeting human tumors growing in mice.

The antiproliferative and antitumor effect of leaf ribonuclease was tested in vitro on the human ML-2 tumor cell line and in vivo on athymic nude mice bearing human melanoma tumors. The antiproliferative activity of this plant ribonuclease in vitro studies was negligible. In the experiments in vivo a significant decrease of the tumor size, however was observed. From nucleases the mung bean nuclease (PhA) was studied first from nucleases. The antitumor effect of this enzyme on ML2 human tumor cell line was almost non-effective. However, significant antitumor activity was detected on human melanoma tumors in vivo. The antitumor effect of black pine pollen nuclease (PN) tested in vitro was also negligible. On the other side, in the experiments in vivo a significant decrease of the human melanoma tumor size was observed too. Recombinant plant nucleases of tomato (TBN1) and hop (HBN1) (submitted to patenting under no. PV 2008-384;Z7585) were isolated to homogeneity and examined for their antitumor effects and cytotoxicity. Although antiproliferative effects of both recombinant nucleases were not significant on the ML-2 cell culture in vitro, the nucleases were strongly cytostatic in vivo after their administration intravenously as stabilized conjugates with polyethylene glycol (PEG). Recombinant both nucleases were as effective against human melanoma tumors as previously studied pine pollen (PN) and mung bean nucleases and their effects were reached at about ten times lower concentrations compared to the use of bovine seminal RNase (BS-RNase).

[Antitumor action of RNAses modified by covalent binding with dextran m-aminobenzylhydroxymethyl ether]. / Protivoopukholevoe deistvie RNK-az, modifitsirovannykh kovalentnym sviazyvaniem s m-aminobenziloksimetilovym éfirom dekstrana.

Antitumor effect of pancreatic RNase and RNase from Actinomyces rimosus, as well as of their derivatives modified by dextran m-aminobenzylhydroxymethyl ether under different conditions was studied and compared. It was found that the efficacy of actinomycetous enzyme and its modified derivatives was superior to that of the analogous preparations of pancreatic RNase. Antitumor effect of the modified enzymes was higher than that of the native ones and depended on the modification conditions. It is concluded that biological efficacy of the RNases is determined by their origin and physico-chemical properties.

[Antitumor action of Ser. marcescens nuclease covalently bound to soluble dextrans]. / Protivoopukholevoe deistvie nukleazy Ser. marcescens, kovalentno sviazannoi s rastvorimymi dekstranami.

The antitumor effect of Ser. marcescens nuclease, modified by covalent binding using the method of diazocoupling with m-aminobenzyloxymethyl dextran of molecular weight 20 000, 40 000, 60 000, exceeds 3--4 times the antitumor effect of the native enzyme in relation to Ehrlich ascites carcinoma in contact tumor cells exposure. In intramuscular injection of the enzyme the nuclease preparation modified by dextran of molecular weight 40 000 showed the greatest antitumor activity against Ehrlich carcinoma and sarcoma 37.