Escherichia coli MW005: lambda Red-mediated recombineering and copy-number induction of oriV-equipped constructs in a single host

<p>Abstract</p> <p>Background</p> <p><it>Escherichia coli </it>strain EL350 contains chromosomally integrated phage lambda Red recombinase genes enabling this strain to be used for modifying the sequence of resident clones <it>via </it>recombineering. BAC and fosmid clones are highly suitable for modification by recombineering but, because they are present at low (1-2) copies per cell, the DNA is difficult to isolate in high yield and purity. To overcome this limitation vectors, e.g. pCC1FOS, have been constructed that contain the additional replication origin, <it>oriV</it>, which permits copy-number to be induced transiently when propagated in a suitable host strain, e.g. EPI300, that supplies the cognate <it>trans</it>-replication protein TrfA. Previously, we used EL350 and EPI300 sequentially to recombineer <it>oriV</it>-equipped fosmid genomic clones and, subsequently, to induce copy-number of the resulting recombinant clone. To eliminate these intervening DNA isolation and transformation steps we retrofitted EL350 with a <it>P</it>_BAD-driven <it>trfA </it>gene generating strain MW005 that supports, independently, both recombineering and copy-number induction.</p> <p>Results</p> <p>The <it>P</it>_BAD-driven copy of <it>cre </it>in EL350 was replaced seamlessly with a copy of <it>trfA</it>, PCR-amplified from EPI300 chromosomal DNA, to generate MW005. This new strain has been used to both generate, via recombineering, a number of reporter gene fusions directly from pCC1FOS-based <it>Caenorhabditis elegans </it>genomic clones and to transiently induce copy-number of fosmid and BAC clones prior to DNA preparation.</p> <p>Conclusions</p> <p>By retrofitting EL350, an established 'recombineering' <it>E. coli </it>strain, with a tightly regulated copy of <it>trfA </it>we have produced a new strain, MW005, which combines recombineering capacity with the useful ability to transiently induce copy-number of <it>oriV</it>-equipped clones. By coupling these two steps in a single strain, use of MW005 will enable the more rapid recombineering-mediated production of recombinant clones in the yield and quality necessary for many downstream purposes.</p

An economic evaluation of radiotherapy for patients with symptomatic Ledderhose disease

BACKGROUND: Evidence for effectiveness of radiotherapy for Ledderhose disease was demonstrated in the LedRad-study. However, the health economic impact of Ledderhose disease is unclear. Therefore, an economic evaluation alongside the LedRad-study was planned.METHODS: The economic evaluation was performed as a cost-effectiveness and cost-utility analysis from the societal perspective. Primary outcome parameters were pain burden and Quality Adjusted Life Years (QALY), until 12 months after the end of treatment. Secondary analyses were performed with outcomes until 18 months. Incremental cost-effectiveness (ICER) and cost-utility ratios (ICUR) were calculated to express costs per unit improvement in pain burden and costs per QALY gained, for radiotherapy compared to sham-radiotherapy. Bootstrap replication was used to assess uncertainty surrounding the ratios and to construct cost-effectiveness acceptability curves for QALY gain.RESULTS: Previous analysis showed a statistically significant improvement in pain- and QoL scores in favour of radiotherapy at 12 and 18 months. At these timepoints and excluding treatment costs, cumulative total costs were considerably lower in the radiotherapy group. The ICER until 12 months after treatment was 4987 euro per unit of pain burden reduction. The ICUR was 14249 euro per QALY gained. Most of the bootstrap replications were in the upper right quadrant, indicating that health gain can be achieved at higher costs. At increasing levels of willingness to pay for a gain in QALY, the probability of cost-utility gradually increased to approximately 85%.CONCLUSIONS: In patients with symptomatic Ledderhose disease, radiotherapy, at a moderate threshold for willingness to pay, is cost-effective in terms of QoL gain.TRIAL REGISTRATION NUMBERS: NCT03507010, NL62429.042.17.</p

Radiotherapy for Ledderhose disease:Results of the LedRad-study, a prospective multicentre randomised double-blind phase 3 trial

Background and purpose: Radiotherapy is considered a treatment option for Ledderhose disease. However, its benefits have never been confirmed in a randomised controlled trial. Therefore, the LedRad-study was conducted. Materials and methods: The LedRad-study is a prospective multicentre randomised double-blind phase three trial. Patients were randomised to sham-radiotherapy (placebo) or radiotherapy. The primary endpoint was pain reduction at 12 months after treatment, measured with the Numeric Rating Scale (NRS). Secondary endpoints were pain reduction at 6 and 18 months after treatment, quality of life (QoL), walking abilities and toxicity.Results: A total of 84 patients were enrolled. At 12 and 18 months, patients in the radiotherapy group had a lower mean pain score compared to patients in the sham-radiotherapy group (2.5 versus 3.6 (p = 0.03) and 2.1 versus 3.4 (p = 0.008), respectively). Pain relief at 12 months was 74% in the radiotherapy group and 56% in the sham-radiotherapy group (p = 0.002). Multilevel testing for QoL scores showed higher QoL scores in the radiotherapy group compared to the sham-radiotherapy group (p &lt; 0.001). Moreover, patients in the radiotherapy group had a higher mean walking speed and step rate with barefoot speed walking (p = 0.02). Erythema, skin dryness, burning sensations and increased pain were the most frequently reported side effects. These side effects were generally graded as mild (95%) and the majority (87%) were resolved at 18 months follow-up.Conclusion: Radiotherapy for symptomatic Ledderhose disease is an effective treatment resulting in a significant pain reduction, improvement of QoL scores and bare feet walking abilities, in comparison to sham-radiotherapy.</p

International comparison of cosmetic outcomes of breast conserving surgery and radiation therapy for women with ductal carcinoma in situ of the breast

Purpose: To assess the cosmetic impact of breast conserving surgery (BCS), whole breast irradiation (WBI) fractionation and tumour bed boost (TBB) use in a phase III trial for women with ductal carcinoma in situ (DCIS) of the breast. Materials and methods: Baseline and 3-year cosmesis were assessed using the European Organization for Research and Treatment of Cancer (EORTC) Cosmetic Rating System and digital images in a randomised trial of non-low risk DCIS treated with postoperative WBI +/- TBB. Baseline cosmesis was assessed for four geographic clusters of treating centres. Cosmetic failure was a global score of fair or poor. Cosmetic deterioration was a score change from excellent or good at baseline to fair or poor at three years. Odds ratios for cosmetic deterioration by WBI dose-fractionation and TBB use were calculated for both scoring systems. Results: 1608 women were enrolled from 11 countries between 2007 and 2014. 85-90% had excellent or good baseline cosmesis independent of geography or assessment method. TBB (16 Gy in 8 fractions) was associated with a >2-fold risk of cosmetic deterioration (p

Sentinel Node Identification Rate and Nodal Involvement in the EORTC 10981-22023 AMAROS Trial

Background The randomized EORTC 10981-22023 AMAROS trial investigates whether breast cancer patients with a tumor-positive sentinel node biopsy (SNB) are best treated with an axillary lymph node dissection (ALND) or axillary radiotherapy (ART). The aim of the current substudy was to evaluate the identification rate and the nodal involvement. Methods The first 2,000 patients participating in the AMAROS trial were evaluated. Associations between the identification rate and technical, patient-, and tumor-related factors were evaluated. The outcome of the SNB procedure and potential further nodal involvement was assessed. Results In 65 patients, the sentinel node could not be identified. As a result, the sentinel node identification rate was 97% (1,888 of 1,953). Variables affecting the success rate were age, pathological tumor size, histology, year of accrual, and method of detection. The SNB results of 65% of the patients (n = 1,220) were negative and the patients underwent no further axillary treatment. The SNB results were positive in 34% of the patients (n = 647), including macrometastases (n = 409, 63%), micrometastases (n = 161, 25%), and isolated tumor cells (n = 77, 12%). Further nodal involvement in patients with macrometastases, micrometastases, and isolated tumor cells undergoing an ALND was 41, 18, and 18%, respectively. Conclusions With a 97% detection rate in this prospective international multicenter study, the SNB procedure is highly effective, especially when the combined method is used. Further nodal involvement in patients with micrometastases and isolated tumor cells in the sentinel node was similar—both were 18%

Current technological clinical practice in breast radiotherapy; results of a survey in EORTC-Radiation Oncology Group affiliated institutions

PURPOSE: To evaluate the current technological clinical practice of radiation therapy of the breast in institutions participating in the EORTC-Radiation Oncology Group (EORTC-ROG). MATERIALS AND METHODS: A survey was conducted between August 2008 and January 2009 on behalf of the Breast Working Party within the EORTC-ROG. The questionnaire comprised 32 questions on 4 main topics: fractionation schedules, treatment planning methods, volume definitions and position verification procedures. RESULTS: Sixty-eight institutions out of 16 countries responded (a response rate of 47%). The standard fraction dose was generally 2Gy for both breast and boost treatment, although a 2.67 Gy boost fraction dose is routinely given in British institutions. The main boost modality was electrons in 55%, photons in 47% and brachytherapy in 3% of the institutions (equal use of photon and electron irradiation in 5% of the institutions). All institutions used CT-based treatment planning. Wide variations are seen in the definition of the breast and boost target volumes, with margins around the resection cavity, ranging from 0 to 30 mm. Inverse planned IMRT is available in 27% and breath-hold techniques in 19% of the institutions. The number of patients treated with IMRT and breath-hold varied per institution. Electronic portal imaging for patient set-up is used by 92% of the institutions. CONCLUSIONS: This survey provides insight in the current practice of radiation technology used in the treatment of breast cancer among institutions participating in EORTC-ROG clinical trials

Counter-selection recombineering of the baculovirus genome: a strategy for seamless modification of repeat-containing BACs

Recombineering is employed to modify large DNA clones such as fosmids, BACs and PACs. Subtle and seamless modifications can be achieved using counter-selection strategies in which a donor cassette carrying both positive and negative markers inserted in the target clone is replaced by the desired sequence change. We are applying counter-selection recombineering to modify bacmid bMON14272, a recombinant baculoviral genome, as we wish to engineer the virus into a therapeutically useful gene delivery vector with cell targeting characteristics. Initial attempts to replace gp64 with Fusion (F) genes from other baculoviruses resulted in many rearranged clones in which the counter-selection cassette had been deleted. Bacmid bMON14272 contains nine highly homologous regions (hrs) and deletions were mapped to recombination between hr pairs. Recombineering modifications were attempted to decrease intramolecular recombination and/or increase recombineering efficiency. Of these only the use of longer homology arms on the donor molecule proved effective permitting seamless modification. bMON14272, because of the presence of the hr sequences, can be considered equivalent to a highly repetitive BAC and, as such, the optimized method detailed here should prove useful to others applying counter-selection recombineering to modify BACs or PACs containing similar regions of significant repeating homologies

Seamless replacement of Autographa californica multiple nucleopolyhedrovirus gp64 with each of five novel type II alphabaculovirus fusion sequences generates pseudotyped virus that fails to transduce mammalian cells

Autographa californica multiple nucleopolyhedrovirus (AcMNPV), a member of the type I alphabaculoviruses, is able to transduce and deliver a functional gene to a range of non-host cells, including many mammalian lines and primary cells, a property mediated by the envelope fusion protein GP64. AcMNPV is non-cytopathic and inherently replication deficient in non-host cells. As such, AcMNPV represents a possible new class of gene therapy vector with potential future clinical utility. Whilst not a problem for in vitro gene delivery, the broad tropism displayed for non-host cells is less desirable in a gene therapy vector. The fusion protein F of type II alphabaculoviruses can substitute functionally for GP64, and such pseudotyped viruses display a severely impaired capacity for non-host-cell transduction. Thus, surface decoration of such an F-pseudotyped AcMNPV with cell-binding ligands may restore transduction competence and generate vectors with desirable cell-targeting characteristics. By seamlessly swapping the native gp64 coding sequence with each of five sequences encoding different F proteins, a set of F-pseudotyped AcMNPV was generated. This report details their relative abilities both to functionally replace GP64 in viral growth and to transduce human Saos-2 and HeLa cells. All five supported viable infections in insect cell cultures and one, the Mamestra configurata NPV (MacoNPV) F pseudotype, could be amplified to titres close to those of native AcMNPV. In contrast, none was able to transduce the Saos-2 and HeLa cell lines. The robust support provided by MacoNPV F in virus production makes the corresponding pseudotype a viable scaffold to display surface ligands to direct selective mammalian cell targeting