Adaptative response to changes in pyruvate metabolism on the epigenetic landscapes and transcriptomics of bovine embryos

The epigenetic reprogramming that occurs during the earliest stages of embryonic development has been described as crucial for the initial events of cell specification and differentiation. Recently, the metabolic status of the embryo has gained attention as one of the main factors coordinating epigenetic events. In this work, we investigate the link between pyruvate metabolism and epigenetic regulation by culturing bovine embryos from day 5 in the presence of dichloroacetate (DCA), a pyruvate analog that increases the pyruvate to acetyl-CoA conversion, and iodoacetate (IA), which inhibits the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), leading to glycolysis inhibition. After 8 h of incubation, both DCA and IA-derived embryos presented higher mitochondrial membrane potential. Nevertheless, in both cases, lower levels of acetyl-CoA, ATP-citrate lyase and mitochondrial membrane potential were found in blastocysts, suggesting an adaptative metabolic response, especially in the DCA group. The metabolic alteration found in blastocysts led to changes in the global pattern of H3K9 and H3K27 acetylation and H3K27 trimethylation. Transcriptome analysis revealed that such alterations resulted in molecular differences mainly associated to metabolic processes, establishment of epigenetic marks, control of gene expression and cell cycle. The latter was further confirmed by the alteration of total cell number and cell differentiation in both groups when compared to the control. These results corroborate previous evidence of the relationship between the energy metabolism and the epigenetic reprogramming in preimplantation bovine embryos, reinforcing that the culture system is decisive for precise epigenetic reprogramming, with consequences for the molecular control and differentiation of cells.

Review: Embryonic stem cells as tools for in vitro gamete production in livestock

The goal of in vitro gametogenesis is to reproduce the events of sperm and oocyte development in the laboratory. Significant advances have been made in the mouse in the last decade, but evolutionary divergence from the murine developmental program has prevented the replication of these advances in large mammals. In recent years, intensive work has been done in humans, non-human primates and livestock to elucidate species-specific differences that regulate germ cell development, due to the number of potential applications. One of the most promising applications is the use of in vitro gametes to optimize the spread of elite genetics in cattle. In this context, embryonic stem cells have been posed as excellent candidates for germ cell platforms. Here, we present the most relevant advances in in vitro gametogenesis of interest to livestock science, including new types of pluripotent stem cells with potential for germline derivation, characterization of the signaling environment in the gonadal niche, and experimental systems used to reproduce different stages of germ cell development in the laboratory.

bESC from cloned embryos do not retain transcriptomic or epigenetic memory from somatic donor cells

In brief

Epigenetic reprogramming after mammalian somatic cell nuclear transfer is often incomplete, resulting in low efficiency of cloning. However, gene expression and histone modification analysis indicated high similarities in transcriptome and epigenomes of bovine embryonic stem cells from in vitro fertilized and somatic cell nuclear transfer embryos.

Abstract

Embryonic stem cells (ESC) indefinitely maintain the pluripotent state of the blastocyst epiblast. Stem cells are invaluable for studying development and lineage commitment, and in livestock, they constitute a useful tool for genomic improvement and in vitro breeding programs. Although these cells have been recently derived from bovine blastocysts, a detailed characterization of their molecular state is lacking. Here, we apply cutting-edge technologies to analyze the transcriptomic and epigenomic landscape of bovine ESC (bESC) obtained from in vitro fertilized (IVF) and somatic cell nuclear transfer (SCNT) embryos. bESC were efficiently derived from SCNT and IVF embryos and expressed pluripotency markers while retaining genome stability. Transcriptome analysis revealed that only 46 genes were differentially expressed between IVF- and SCNT-derived bESC, which did not reflect significant deviation in cellular function. Interrogating histone 3 lysine 4 trimethylation, histone 3 lysine 9 trimethylation, and histone 3 lysine 27 trimethylation with cleavage under targets and tagmentation, we found that the epigenomes of both bESC groups were virtually indistinguishable. Minor epigenetic differences were randomly distributed throughout the genome and were not associated with differentially expressed or developmentally important genes. Finally, the categorization of genomic regions according to their combined histone mark signal demonstrated that all bESC shared the same epigenomic signatures, especially at gene promoters. Overall, we conclude that bESC derived from SCNT and IVF embryos are transcriptomically and epigenetically analogous, allowing for the production of an unlimited source of pluripotent cells from high genetic merit organisms without resorting to transgene-based techniques.

Acquisition and maintenance of pluripotency are influenced by fibroblast growth factor, leukemia inhibitory factor, and 2i in bovine-induced pluripotent stem cells

Several opportunities for embryo development, stem cell maintenance, cell fate, and differentiation have emerged using induced pluripotent stem cells (iPSCs). However, the difficulty in comparing bovine iPSCs (biPSCs) with embryonic stem cells (ESCs) was a challenge for many years. Here, we reprogrammed fetal fibroblasts by transient expression of the four transcription factors (Oct4, Sox2, Klf4, and c-Myc, collectively termed “OSKM” factors) and cultured in iPSC medium, supplemented with bFGF, bFGF2i, leukemia inhibitory factor (LIF), or LIF2i, and then compared these biPSC lines with bESC to evaluate the pluripotent state. biPSC lines were generated in all experimental groups. Particularly, reprogrammed cells treated with bFGF were more efficient in promoting the acquisition of pluripotency. However, LIF2i treatment did not promote continuous self-renewal. biPSCs (line 2) labeled with GFP were injected into early embryos (day 4.5) to assess the potential to contribute to chimeric blastocysts. The biPSC lines show a pluripotency state and are differentiated into three embryonic layers. Moreover, biPSCs and bESCs labeled with GFP were able to contribute to chimeric blastocysts. Additionally, biPSCs have shown promising potential for contributing to chimeric blastocysts and for future studies.

Results of a single-arm pilot study of 32P microparticles in unresectable locally advanced pancreatic adenocarcinoma with gemcitabine/nab-paclitaxel or FOLFIRINOX chemotherapy

Background

Unresectable locally advanced pancreatic cancer (LAPC) is generally managed with chemotherapy or chemoradiotherapy, but prognosis is poor with a median survival of ∼13 months (or up to 19 months in some studies). We assessed a novel brachytherapy device, using phosphorous-32 (³²P) microparticles, combined with standard-of-care chemotherapy.

Patients and methods

In this international, multicentre, single-arm, open-label pilot study, adult patients with histologically or cytologically proven unresectable LAPC received ³²P microparticles, via endoscopic ultrasound-guided fine-needle implantation, planned for week 4 of 5-fluorouracil, leucovorin, irinotecan and oxaliplatin (FOLFIRINOX) or gemcitabine/nab-paclitaxel chemotherapy, per investigator’s choice. The primary endpoint was safety and tolerability measured using Common Terminology Criteria for Adverse Events version 4.0. The lead efficacy endpoint was local disease control rate at 16 weeks.

Results

Fifty patients were enrolled and received chemotherapy [intention-to-treat (ITT) population]. Forty-two patients received ³²P microparticle implantation [per protocol (PP) population]. A total of 1102 treatment-emergent adverse events (TEAEs) were reported in the ITT/safety population (956 PP), of which 167 (139 PP) were grade ≥3. In the PP population, 41 TEAEs in 16 (38.1%) patients were possibly or probably related to ³²P microparticles or implantation procedure, including 8 grade ≥3 in 3 (7.1%) patients, compared with 609 TEAEs in 42 (100%) patients attributed to chemotherapy, including 67 grade ≥3 in 28 patients (66.7%). The local disease control rate at 16 weeks was 82.0% (95% confidence interval: 68.6% to 90.9%) (ITT) and 90.5% (95% confidence interval: 77.4% to 97.3%) (PP). Tumour volume, carbohydrate antigen 19-9 levels, and metabolic tumour response at week 12 improved significantly. Ten patients (20.0% ITT; 23.8% PP) had surgical resection and median overall survival was 15.2 and 15.5 months for ITT and PP populations, respectively.

Conclusions

Endoscopic ultrasound-guided ³²P microparticle implantation has an acceptable safety profile. This study also suggests clinically relevant benefits of combining ³²P microparticles with standard-of-care systemic chemotherapy for patients with unresectable LAPC.

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PanCO is the first prospective study of intratumoural ³²P microparticles for locally advanced pancreatic cancer (LAPC).

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This single-arm study assessed a novel brachytherapy (³²P microparticles) combined with standard-of-care chemotherapy.

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Treatment-emergent adverse events attributable to ³²P microparticle implantation were relatively infrequent.

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Local disease control rate at 16 weeks (82%) and resection rate (20%) suggest a clinical benefit of ³²P microparticles.

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The results suggest that ³²P microparticles may address a significant unmet need in patients with unresectable LAPC.

Genome activation in equine in vitro-produced embryos

Embryonic genome activation is a critical event in embryo development, in which the transcriptional program of the embryo is initiated. The timing and regulation of this process are species-specific. In vitro embryo production is becoming an important clinical and research tool in the horse; however, very little is known about genome activation in this species. The objective of this work was to identify the timing of genome activation, and the transcriptional networks involved, in in vitro-produced horse embryos. RNA-Seq was performed on oocytes and embryos at eight stages of development (MII, zygote, 2-cell, 4-cell, 8-cell, 16-cell, morula, blastocyst; n = 6 per stage, 2 from each of 3 mares). Transcription of seven genes was initiated at the 2-cell stage. The first substantial increase in gene expression occurred at the 4-cell stage (minor activation), followed by massive gene upregulation and downregulation at the 8-cell stage (major activation). An increase in intronic nucleotides, indicative of transcription initiation, was also observed at the 4-cell stage. Co-expression network analyses identified groups of genes that appeared to be regulated by common mechanisms. Investigation of hub genes and binding motifs enriched in the promoters of co-expressed genes implicated several transcription factors. This work represents, to the best of our knowledge, the first genomic evaluation of embryonic genome activation in horse embryos.

Allele-specific expression analysis reveals conserved and unique features of preimplantation development in equine ICSI embryos

Embryonic genome activation and dosage compensation are major genetic events in early development. Combined analysis of single embryo RNA-seq data and parental genome sequencing was used to evaluate parental contributions to early development and investigate X-chromosome dynamics. In addition, we evaluated dimorphism in gene expression between male and female embryos. Evaluation of parent-specific gene expression revealed a minor increase in paternal expression at the 4-cell stage that increased at the 8-cell stage. We also detected eight genes with allelic expression bias that may have an important role in early development, notably NANOGNB. The main actor in X-chromosome inactivation, XIST, was significantly upregulated at the 8-cell, morula, and blastocyst stages in female embryos, with high expression at the latter. Sexual dimorphism in gene expression was identified at all stages, with strong representation of the X-chromosome in females from the 16-cell to the blastocyst stage. Female embryos showed biparental X-chromosome expression at all stages after the 4-cell stage, demonstrating the absence of imprinted X-inactivation at the embryo level. The analysis of gene dosage showed incomplete dosage compensation (0.5 < X:A < 1) in MII oocytes and embryos up to the 4-cell stage, an increase of the X:A ratio at the 16-cell and morula stages after genome activation, and a decrease of the X:A ratio at the blastocyst stage, which might be associated with the beginning of X-chromosome inactivation. This study represents the first critical analysis of parent- and sex-specific gene expression in early equine embryos produced in vitro.

Derivation of sheep embryonic stem cells under optimized conditions

Until recently, it has been difficult to derive and maintain stable embryonic stem cells lines from livestock species. Sheep ESCs with characteristics similar to those described for rodents and primates have not been produced. We report the derivation of sheep ESCs under a chemically defined culture system containing fibroblast growth factor 2 (FGF2) and a tankyrase/Wnt inhibitor (IWR1). We also show that several culture conditions used for stabilizing naïve and intermediate pluripotency states in humans and mice were unsuitable to maintain ovine pluripotency in vitro. Sheep ESCs display a smooth dome-shaped colony morphology, and maintain an euploid karyotype and stable expression of pluripotency markers after more than 40 passages. We further demonstrate that IWR1 and FGF2 are essential for the maintenance of an undifferentiated state in de novo derived sheep ESCs. The derivation of stable pluripotent cell lines from sheep blastocysts represents a step forward toward understanding pluripotency regulation in livestock species and developing novel biomedical and agricultural applications.

Metabolism-driven post-translational modifications of H3K9 in early bovine embryos

Metabolic and molecular profiles were reported as different for bovine embryos with distinct kinetics during the first cleavages. In this study, we used this same developmental model (fast vs slow) to determine if the relationship between metabolism and developmental kinetics affects the levels of acetylation or tri-methylation at histone H3 lysine 9 (H3K9ac and H3K9me3, respectively). Fast and slow developing embryos presented different levels of H3K9ac and H3K9me3 from the earliest stages of development (40 and 96 hpi) and up to the blastocyst stage. For H3K9me3, both groups of embryos presented a wave of demethylation and de novo methylation, although it was more pronounced in fast than slow embryos, resulting in blastocysts with higher levels of this mark. The H3K9ac reprogramming profile was distinct between kinetics groups. While slow embryos presented a wave of deacetylation, followed by an increase in this mark at the blastocyst stage, fast embryos reduced this mark throughout all the developmental stages studied. H3K9me3 differences corresponded to writer and eraser transcript levels, while H3K9ac patterns were explained by metabolism-related gene expression. To verify if metabolic differences could alter levels of H3K9ac, embryos were cultured with sodium-iodoacetate (IA) or dichloroacetate (DCA) to disrupt the glycolytic pathway or increase acetyl-CoA production, respectively. IA reduced H3K9ac while DCA increased H3K9ac in blastocysts. Concluding, H3K9me3 and H3K9ac patterns differ between embryos with different kinetics, the second one explained by metabolic pathways involved in acetyl-CoA production. So far, this is the first study demonstrating a relationship between metabolic differences and histone post-translational modifications in bovine embryos.

Effects of sodium salicylate and time postpartum on mammary tissue proliferation, gene transcript profile, and DNA methylation

Previous studies have demonstrated nonsteroidal antiinflammatory drug treatment in early lactation had a positive impact on whole-lactation milk production in older cows. The objective of this study was to evaluate proliferative, transcriptional, and epigenetic changes in the mammary gland that could explain increased production responses due to nonsteroidal antiinflammatory drug treatment. Sodium salicylate (SAL; 125 g/d) or water (CON) were administered via oral drench to multiparous Holstein cows (n = 8/treatment) once daily for 3 d beginning approximately 24 h after parturition, and mammary tissue was collected on d 1, 4, and 45 postpartum. Day 1 tissue was collected immediately preceding the initial drench, and d 4 tissue was collected 24 h following the final drench. Blood was collected twice weekly and analyzed for plasma glucose, insulin, β-hydroxybutyrate, free fatty acids, and prolactin. Cows were milked twice daily until d 7 of lactation, and thrice daily for the remainder of the study. Total RNA extracted from tissue was deep-sequenced and analyzed for differential gene expression using DESeq2. We detected no treatment effect on milk yield or plasma metabolites through 45 d of lactation; additionally, no change in mammary epithelial cell proliferation was detected when assessed by Ki67 labeling. Comparison of SAL versus CON revealed that only 16 of 18,286 genes were differentially expressed (false discovery rate <0.1) in mammary tissue collected on d 45, whereas no differentially expressed genes due to treatment were detected on d 1 or 4. Analysis of transcriptional differences over time showed downregulation of pathways related to immune cell recruitment and differentiation, and extensive overlap with pathways related to cholesterol synthesis and liver X receptor signaling. Global DNA methylation of mammary tissue was decreased for CON compared with SAL. Transcriptome analysis emphasized extensive involvement of immune-related signaling pathways in the switch from lactogenesis to galactopoiesis, and changes in methylation with SAL treatment merit future investigation into epigenetic effects on milk production.

Simplification of culture conditions and feeder-free expansion of bovine embryonic stem cells

Bovine embryonic stem cells (bESCs) extend the lifespan of the transient pluripotent bovine inner cell mass in vitro. After years of research, derivation of stable bESCs was only recently reported. Although successful, bESC culture relies on complex culture conditions that require a custom-made base medium and mouse embryonic fibroblasts (MEF) feeders, limiting the widespread use of bESCs. We report here simplified bESC culture conditions based on replacing custom base medium with a commercially available alternative and eliminating the need for MEF feeders by using a chemically-defined substrate. bESC lines were cultured and derived using a base medium consisting of N2B27 supplements and 1% BSA (NBFR-bESCs). Newly derived bESC lines were easy to establish, simple to propagate and stable after long-term culture. These cells expressed pluripotency markers and actively proliferated for more than 35 passages while maintaining normal karyotype and the ability to differentiate into derivatives of all three germ lineages in embryoid bodies and teratomas. In addition, NBFR-bESCs grew for multiple passages in a feeder-free culture system based on vitronectin and Activin A medium supplementation while maintaining pluripotency. Simplified conditions will facilitate the use of bESCs for gene editing applications and pluripotency and lineage commitment studies.

Similarities between bovine and human germline development revealed by single-cell RNA sequencing

The germ cell lineage ensures the creation of new individuals and perpetuates the genetic information across generations. Primordial germ cells are pioneers of gametes and exist transiently during development until they differentiate into oogonia in females, or spermatogonia in males. Little is known about the molecular characteristics of primordial germ cells in cattle. By performing single-cell RNA-sequencing, quantitative real-time PCR, and immunofluorescence analyses of fetal gonads between 40 and 90 days of fetal age, we evaluated the molecular signatures of bovine germ cells at the initial stages of gonadal development. Our results indicate that at 50 days of fetal age, bovine primordial germ cells were in the early stages of development, expressing genes of early primordial germ cells, including transcriptional regulators of human germline specification (e.g. SOX17, TFAP2C, and PRDM1). Bovine and human primordial germ cells also share expression of KIT, EPCAM, ITGA6, and PDPN genes coding for membrane-bound proteins, and an asynchronous pattern of differentiation. Additionally, the expression of members of Notch, Nodal/Activin, and BMP signaling cascades in the bovine fetal ovary, suggests that these pathways are involved in the interaction between germ cells and their niche. Results of this study provide insights into the mechanisms involved in the development of bovine primordial germ cells and put in evidence similarities between the bovine and human germline.

Efficient One-Step Knockout by Electroporation of Ribonucleoproteins Into Zona-Intact Bovine Embryos

Somatic cell nuclear transfer or cytoplasm microinjection have been used to generate genome-edited farm animals; however, these methods have several drawbacks that reduce their efficiency. This study aimed to develop electroporation conditions that allow delivery of CRISPR/Cas9 system to bovine zygotes for efficient gene knock-out. We optimized electroporation conditions to deliver Cas9:sgRNA ribonucleoproteins to bovine zygotes without compromising embryo development. Higher electroporation pulse voltage resulted in increased membrane permeability; however, voltages above 15 V/mm decreased embryo developmental potential. The zona pellucida of bovine embryos was not a barrier to efficient RNP electroporation. Using parameters optimized for maximal membrane permeability while maintaining developmental competence we achieved high rates of gene editing when targeting bovine OCT4, which resulted in absence of OCT4 protein in 100% of the evaluated embryos and the expected arrest of embryonic development at the morula stage. In conclusion, Cas9:sgRNA ribonucleoproteins can be delivered efficiently by electroporation to zona-intact bovine zygotes, resulting in efficient gene knockouts.

Systematic alteration of ATAC-seq for profiling open chromatin in cryopreserved nuclei preparations from livestock tissues

The use of Assay for Transposase-Accessible Chromatin (ATAC-seq) to profile chromatin accessibility has surged over the past years, but its applicability to tissues has been very limited. With the intent of preserving nuclear architecture during long-term storage, cryopreserved nuclei preparations from chicken lung were used to optimize ATAC-seq. Sequencing data were compared with existing DNase-seq, ChIP-seq, and RNA-seq data to evaluate library quality, ultimately resulting in a modified ATAC-seq method capable of generating high quality chromatin accessibility data from cryopreserved nuclei preparations. Using this method, nucleosome-free regions (NFR) identified in chicken lung overlapped half of DNase-I hypersensitive sites, coincided with active histone modifications, and specifically marked actively expressed genes. Notably, sequencing only the subnucleosomal fraction dramatically improved signal, while separation of subnucleosomal reads post-sequencing did not improve signal or peak calling. The broader applicability of this modified ATAC-seq technique was tested using cryopreserved nuclei preparations from pig tissues, resulting in NFR that were highly consistent among biological replicates. Furthermore, tissue-specific NFR were enriched for binding motifs of transcription factors related to tissue-specific functions, and marked genes functionally enriched for tissue-specific processes. Overall, these results provide insights into the optimization of ATAC-seq and a platform for profiling open chromatin in animal tissues.

4324Fast-field cycling magnetic resonance detection of intracellular iron in the nanomolar range - A pre-requisite for in-vivo study of inflammation

Background

Ultra-small superparamagnetic iron oxide (USPIO) nanoparticles are phagocytosed by macrophages and when subjected to magnetic resonance imaging (MRI) detect inflammation. We describe a novel MR technique where the magnetic field is rapidly cycled (Fast field-cycling MR, FFC-MR), assessing T1 dispersion over a range of low (100μT-0.2T) fields and offering superior T1-based iron quantification.

AIM

To quantify iron using the FFC-MR R1 (1/T1) dispersion profile and flow cytometry features of USPIO-laden cells, in comparison to colorimetric assays.

Methods

Murine J774 macrophage-like cells were incubated with 0–200μg/ml Fe as USPIO (ferumoxytol) for 16 hours, washed and suspended in 500μl PBS/2mM EDTA. Prussian blue staining confirmed USPIO phagocytosis. Relaxation was measured using a clinical, in-house built prototype 0.2T FFC-MR system with a custom test tube coil. R1 dispersion was derived from a saturation recovery sequence (Fig. 1A). R1 (s–1) values were calculated with a monoexponential curve fitting algorithm, R2 of fits were ≥0.999. R1 dispersion profiles were generated plotting R1 against the magnetic field (T). Quantification of side scatter (SCC) intensity and the USPIO-occupied fraction of total cell area was performed with imaging flow cytometry. A colorimetric assay provided validation of cell iron content. All data are mean±SEM, analysed with t-tests, Pearson correlation and linear regression; statistical significance set at p<0.05.

Results

Table 1 shows quantitative data derived by all 3 modalities with increasing USPIO exposure. FFC-MR detection of intracellular iron was excellent (p≤0.001 vs. control for all), with separation of average R1 dispersion profiles (Fig. 1B), strong correlation with colorimetry (r=0.993 p<0.001) and good fit on linear regression model (R2=0.9222, Fig 1C). Flow cytometry quantification of SCC was comparable (p≤0.001 for all), whereas USPIO-occupied area was only sensitive at exposures ≥10μg/ml USPIO (r=0.967 p<0.001 & r=0.983 p<0.001 vs. colorimetric respectively). FFC-MR detected iron at ≥1.12ng/μg protein.

USPIO exposure (μg/ml medium) 0 5 10 40 80 100 200 FFC-MR Mean R1 1x106 cell suspension (s–1) 0.308±0.014 0.356±0.013** 0.432±0.016** 0.706±0.021** 1.174±0.031** 1.239±0.033** 1.599±0.041** Flow cytometry USPIO area/cell area 0.034±0.001 0.036±0.001 0.037±0.001* 0.069±0.001** 0.085±0.001** 0.090±0.001** 0.097±0.001** Flow cytometry SSC intensity 26860 32815** 39573** 69285** 80967** 82693** 86373** Colorimetric assay Iron concentration 1x106 cells (ng/μg protein) 0.115±0.118 1.121±0.045** 2.074±0.084** 5.496±0.134** 8.421±0.269** 9.771±0.100** 12.398±0.233** SSC = side-scattered light; *p<0.05 vs. control; **p<0.001 vs. control.

Conclusion

Field-cycling MR is capable of highly accurate intracellular USPIO quantification, which has potential to non-invasively detect clinically relevant amounts of iron in inflammatory cardiovascular diseases.

Acknowledgement/Funding

NHS Grampian Endowment Fund

Impaired Spermatogenesis, Muscle, and Erythrocyte Function in U12 Intron Splicing-Defective Zrsr1 Mutant Mice

The U2AF35-like ZRSR1 has been implicated in the recognition of 3' splice site during spliceosome assembly, but ZRSR1 knockout mice do not show abnormal phenotypes. To analyze ZRSR1 function and its precise role in RNA splicing, we generated ZRSR1 mutant mice containing truncating mutations within its RNA-recognition motif. Homozygous mutant mice exhibited severe defects in erythrocytes, muscle stretch, and spermatogenesis, along with germ cell sloughing and apoptosis, ultimately leading to azoospermia and male sterility. Testis RNA sequencing (RNA-seq) analyses revealed increased intron retention of both U2- and U12-type introns, including U12-type intron events in genes with key functions in spermatogenesis and spermatid development. Affected U2 introns were commonly found flanking U12 introns, suggesting functional cross-talk between the two spliceosomes. The splicing and tissue defects observed in mutant mice attributed to ZRSR1 loss of function suggest a physiological role for this factor in U12 intron splicing.

Evaluation of protective and immune responses following vaccination with recombinant MIP and CPAF from Chlamydia abortus as novel vaccines for enzootic abortion of ewes

MIP and CPAF from Chlamydia have been shown to be effective in inducing immune responses important in clearing chlamydial infections. This study evaluates the protection conferred by MIP and CPAF as novel vaccines in pregnant C. abortus challenged ewes. Fifty C. abortus sero-negative sheep were randomly allocated into 5 groups of 10 according to the treatment they were to receive (1) 100 µg of MBP-MIP (2) 100 µg CPAF (3) 50 µg MBP-MIP and 50 µg CPAF (4) Tris-buffer (negative control) (5) Enzovax (positive control). Booster inoculations were administered 3 weeks after primary inoculations. Blood samples were taken pre-vaccination and weekly for 5 weeks. Five months after vaccination the ewes were mated. Pregnant ewes were then challenged on day 90 of gestation. Blood samples taken at four time-points post challenge were analysed for IFNγ levels, TNFα and IL-10 expression and anti-chlamydial antibody levels. Vaginal swabs, placental and foetal tissue and bacterial shedding were analysed using qPCR to quantify levels of C. abortus. Enzovax was 100% effective with no abortions occurring. The MIP/CPAF combined vaccine offered the greatest protection of the novel vaccines with 67% of ewes giving birth to one or more live lambs equating to a 50% vaccine efficacy rate. MIP and CPAF administered singly did not confer protection. Enzovax and MIP/CPAF vaccinated ewes had longer gestations and lambs with higher birth weights than negative control ewes. Aborting ewes shed higher numbers of C. abortus than ewes that had live lambs, all vaccinated ewes demonstrated lower levels of bacterial shedding than negative control ewes with Enzovax ewes shedding significantly fewer bacteria. Ewes that went on to abort had significantly higher levels of IFNγ and IL-10 at day 35 post challenge and significantly higher levels of anti-chlamydial antibodies at 24 h post lambing compared to ewes that had live lambs.

Mosaicism diminishes the value of pre-implantation embryo biopsies for detecting CRISPR/Cas9 induced mutations in sheep

The production of knock-out (KO) livestock models is both expensive and time consuming due to their long gestational interval and low number of offspring. One alternative to increase efficiency is performing a genetic screening to select pre-implantation embryos that have incorporated the desired mutation. Here we report the use of sheep embryo biopsies for detecting CRISPR/Cas9-induced mutations targeting the gene PDX1 prior to embryo transfer. PDX1 is a critical gene for pancreas development and the target gene required for the creation of pancreatogenesis-disabled sheep. We evaluated the viability of biopsied embryos in vitro and in vivo, and we determined the mutation efficiency using PCR combined with gel electrophoresis and digital droplet PCR (ddPCR). Next, we determined the presence of mosaicism in ~ 50% of the recovered fetuses employing a clonal sequencing methodology. While the use of biopsies did not compromise embryo viability, the presence of mosaicism diminished the diagnostic value of the technique. If mosaicism could be overcome, pre-implantation embryo biopsies for mutation screening represents a powerful approach that will streamline the creation of KO animals.

Differing molecular response of young and advanced maternal age human oocytes to IVM

STUDY QUESTION

What effect does maternal age have on the human oocyte's molecular response to in vitro oocyte maturation?

SUMMARY ANSWER

Although polyadenylated transcript abundance is similar between young and advanced maternal age (AMA) germinal vesicle (GV) oocytes, metaphase II (MII) oocytes exhibit a divergent transcriptome resulting from a differential response to in vitro oocyte maturation.

WHAT IS KNOWN ALREADY

Microarray studies considering maternal age or maturation stage have shown that either of these factors will affect oocyte polyadenylated transcript abundance in human oocytes. However, studies considering both human oocyte age and multiple stages simultaneously are limited to a single study that examined transcript levels for two genes by qPCR. Thus, polyadenylated RNA sequencing (RNA-Seq) could provide novel insight into age-associated aberrations in gene expression in GV and MII oocytes.

STUDY DESIGN, SIZE, DURATION

The effect of maternal age (longitudinal analysis) on polyadenylated transcript abundance at different stages was analyzed by examining single GV and single in vitro matured MII oocytes derived from five young (YNG; < 30 years; average age 26.8; range 20-29) and five advanced maternal age (AMA; ≥40 years; average age 41.6 years; range 40-43 years) patients. Thus, a total of 10 YNG (5 GV and 5 MII) and 10 AMA (5 GV and 5 MII) oocytes were individually processed for RNA-Seq analysis.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Patients undergoing infertility treatment at the Colorado Center for Reproductive Medicine (Lone Tree, CO, USA) underwent ovarian stimulation with FSH and received hCG for final follicular maturation prior to ultrasound guided oocyte retrieval. Unused GV oocytes obtained at retrieval were donated for transcriptome analysis. Single oocytes were stored (at -80°C in PicoPure RNA Extraction Buffer; Thermo Fisher Scientific, USA) immediately upon verification of immaturity or after undergoing in vitro oocyte maturation (24 h incubation), representing GV and MII samples, respectively. After isolating RNA and generating single oocyte RNA-Seq libraries (SMARTer Ultra Low Input RNA HV kit; Clontech, USA), Illumina sequencing (100 bp paired-end reads on HiSeq 2500) and bioinformatics analysis (CLC Genomics Workbench, DESeq2, weighted gene correlation network analysis (WGCNA), Ingenuity Pathway Analysis) were performed.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 12 770 genes were determined to be expressed in human oocytes (reads per kilobase per million mapped reads (RPKM) > 0.4 in at least three of five replicates for a minimum of one sample type). Differential gene expression analysis between YNG and AMA oocytes (within stage) identified 1 and 255 genes that significantly differed (adjusted P < 0.1 and log2 fold change >1) in polyadenylated transcript abundance for GV and MII oocytes, respectively. These genes included CDK1, NLRP5 and PRDX1, which have been reported to affect oocyte developmental potential. Despite the similarity in transcript abundance between GV oocytes irrespective of age, divergent expression patterns emerged during oocyte maturation. These age-specific differentially expressed genes were enriched (FDR < 0.05) for functions and pathways associated with mitochondria, cell cycle and cytoskeleton. Gene modules generated by WGCNA (based on gene expression) and patient traits related to oocyte quality (e.g. age and blastocyst development) were correlated (P < 0.05) and enriched (FDR < 0.05) for functions and pathways associated with oocyte maturation.

LARGE SCALE DATA

Raw data from this study can be accessed through GSE95477.

LIMITATIONS, REASONS FOR CAUTION

The human oocytes used in the current study were obtained from patients with varying causes of infertility (e.g. decreased oocyte quality and oocyte quality-independent factors), possibly affecting oocyte gene expression. Oocytes in this study were retrieved at the GV stage following hCG administration and the MII oocytes were derived by IVM of patient oocytes. Although the approach has the benefit of identifying intrinsic differences between samples, it may not be completely representative of in vivo matured oocytes.

WIDER IMPLICATIONS OF THE FINDINGS

Transcriptome profiles of YNG and AMA oocytes, particularly at the MII stage, suggest that aberrant transcript abundance may contribute to the age-associated decline in fertility.

STUDY FUNDING/COMPETING INTEREST(S)

J.M.R. was supported by an Austin Eugene Lyons Fellowship awarded by the University of California, Davis. The Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (awarded to P.J.R.; R01HD070044) and the Fertility Laboratories of Colorado partly supported the research presented in this manuscript.

Effect of different mini-volume colloid centrifugation configurations on flow cytometrically sorted sperm recovery efficiency and quality using a computer-assisted semen analyzer

Straws of sex-sorted sperm are usually packaged at a low concentration (e.g., ~2.1 × 10⁶  sperm/ml) and cost significantly more than unsorted conventional semen from the same sire. In order to maximize the efficiency of using sex-sorted sperm under in vitro fertilization conditions, the selection of an appropriate sperm separation technique is essential. In this study, the effect of using different silane-coated silica colloid dilutions and layering configurations during centrifugation of sex-sorted sperm was examined over an extended period of incubation time. Sperm recovery and viability after centrifugation using the colloid separation technique were measured along with several sperm motility parameters using CASA. For this purpose, frozen and thawed sex-sorted sperm samples were centrifuged using mini-volume single-layer (40%, 60% and 80%) and mini-volume two-layer (45%/90%, 40%/80% and 30%/60%) separation configurations using PureSperm^® . A single layer of 40% PureSperm^® recovered significantly more sex-sorted sperm (78.07% ± 2.28%) followed by a single layer of 80% PureSperm^® (68.43% ± 2.33%). The lowest sperm recovery was obtained using a two-layer PureSperm^® dilution of 45%/90% (47.57% ± 2.33%). Single-layer centrifugation recovered more sorted sperm (68.67% ± 1.74%) than two layer (53.74% ± 1.74%) (p < .0001). A single layer of 80% PureSperm^® exhibited the highest sorted sperm viability (72.01% ± 2.90%) after centrifugation (p < .05). The mini-volume single layer of 80% PureSperm^® was determined to be an effective alternative to a two-layer centrifugation configuration for sex-sorted sperm selection. In addition, single-layer colloid dilution of 80% performed either as well as or significantly outperformed the other treatments, as well as the control, with regard to motility (MOT) for all time periods of analysis.

CRISPR-Cas9 mediated one-step disabling of pancreatogenesis in pigs

Genome editing using programmable nucleases has revolutionized biomedical research. CRISPR-Cas9 mediated zygote genome editing enables high efficient production of knockout animals suitable for studying development and relevant human diseases. Here we report efficient disabling pancreatogenesis in pig embryos via zygotic co-delivery of Cas9 mRNA and dual sgRNAs targeting the PDX1 gene, which when combined with chimeric-competent human pluriopotent stem cells may serve as a suitable platform for the xeno-generation of human tissues and organs in pigs.

Interspecies Chimerism with Mammalian Pluripotent Stem Cells

Interspecies blastocyst complementation enables organ-specific enrichment of xenogenic pluripotent stem cell (PSC) derivatives. Here, we establish a versatile blastocyst complementation platform based on CRISPR-Cas9-mediated zygote genome editing and show enrichment of rat PSC-derivatives in several tissues of gene-edited organogenesis-disabled mice. Besides gaining insights into species evolution, embryogenesis, and human disease, interspecies blastocyst complementation might allow human organ generation in animals whose organ size, anatomy, and physiology are closer to humans. To date, however, whether human PSCs (hPSCs) can contribute to chimera formation in non-rodent species remains unknown. We systematically evaluate the chimeric competency of several types of hPSCs using a more diversified clade of mammals, the ungulates. We find that naïve hPSCs robustly engraft in both pig and cattle pre-implantation blastocysts but show limited contribution to post-implantation pig embryos. Instead, an intermediate hPSC type exhibits higher degree of chimerism and is able to generate differentiated progenies in post-implantation pig embryos.

Tissue resolved, gene structure refined equine transcriptome

BACKGROUND

Transcriptome interpretation relies on a good-quality reference transcriptome for accurate quantification of gene expression as well as functional analysis of genetic variants. The current annotation of the horse genome lacks the specificity and sensitivity necessary to assess gene expression especially at the isoform level, and suffers from insufficient annotation of untranslated regions (UTR) usage. We built an annotation pipeline for horse and used it to integrate 1.9 billion reads from multiple RNA-seq data sets into a new refined transcriptome.

RESULTS

This equine transcriptome integrates eight different tissues from 59 individuals and improves gene structure and isoform resolution, while providing considerable tissue-specific information. We utilized four levels of transcript filtration in our pipeline, aimed at producing several transcriptome versions that are suitable for different downstream analyses. Our most refined transcriptome includes 36,876 genes and 76,125 isoforms, with 6474 candidate transcriptional loci novel to the equine transcriptome.

CONCLUSIONS

We have employed a variety of descriptive statistics and figures that demonstrate the quality and content of the transcriptome. The equine transcriptomes that are provided by this pipeline show the best tissue-specific resolution of any equine transcriptome to date and are flexible for several downstream analyses. We encourage the integration of further equine transcriptomes with our annotation pipeline to continue and improve the equine transcriptome.

Mechanisms of epigenetic remodelling during preimplantation development

Epigenetics involves mechanisms independent of modifications in the DNA sequence that result in changes in gene expression and are maintained through cell divisions. Because all cells in the organism contain the same genetic blueprint, epigenetics allows for cells to assume different phenotypes and maintain them upon cell replication. As such, during the life cycle, there are moments in which the epigenetic information needs to be reset for the initiation of a new organism. In mammals, the resetting of epigenetic marks occurs at two different moments, which both happen to be during gestation, and include primordial germ cells (PGCs) and early preimplantation embryos. Because epigenetic information is reversible and sensitive to environmental changes, it is probably no coincidence that both these extensive periods of epigenetic remodelling happen in the female reproductive tract, under a finely controlled maternal environment. It is becoming evident that perturbations during the extensive epigenetic remodelling in PGCs and embryos can lead to permanent and inheritable changes to the epigenome that can result in long-term changes to the offspring derived from them, as indicated by the Developmental Origins of Health and Disease (DOHaD) hypothesis and recent demonstration of inter- and trans-generational epigenetic alterations. In this context, an understanding of the mechanisms of epigenetic remodelling during early embryo development is important to assess the potential for gametic epigenetic mutations to contribute to the offspring and for new epimutations to be established during embryo manipulations that could affect a large number of cells in the offspring. It is of particular interest to understand whether and how epigenetic information can be passed on from the gametes to the embryo or offspring, and whether abnormalities in this process could lead to transgenerationally inheritable phenotypes. The aim of this review is to highlight recent progress made in understanding the nature and mechanisms of epigenetic remodelling that ensue after fertilisation.

A comprehensive geriatric assessment screening questionnaire (CGA-GOLD) for older people undergoing treatment for cancer

Oncology services do not routinely assess broader needs of older people with cancer. This study evaluates a comprehensive geriatric assessment and comorbidity screening questionnaire (CGA-GOLD) covering evidence-based domains and quality of life (EORTC-QLQ-C30). Patients aged 65+ attending oncology services were recruited into (1) Observational cohort (completed CGA-GOLD, received standard oncology care), (2) Intervention cohort (responses categorised 'low-risk', 'high-risk', 'possible need' by geriatricians). N = 417 observational patients (1002 invited by post, 418 consented, age 73.9 ± 5.4) completed CGA-GOLD in 11.7 ± 7.9 min, 86.3% required no assistance, 3.1% overall missing responses. Multiple problems reported: hypertension (18.1%), diabetes (16.9%), dyspnoea on flat surfaces (27.6%), polypharmacy (46%), difficulty walking (14.9%), fatigue (40.5%), living alone (30.9%), social isolation (11.2%), recent functional dependence (27.8%), urinary incontinence (21.4%), falls (13.3%). 237/239 intervention patients completed CGA-GOLD and consecutive subsets examined. The doctor and nurse specialist independently identified same need level in 87.3% (high inter-rater reliability kappa = 0.80), taking 1-2 min per questionnaire. Need level remained unchanged following hospital notes review against responses in 90% (75/83). 'Possible need' patients were telephoned with change in 29% (16/55) to low-risk and none to high-risk, confirming high need was not being missed. CGA-GOLD screening questionnaire was acceptable to older patients, feasibly administered in NHS cancer services, described comorbidities, CGA and QOL needs, and reliably identified higher risk patients requiring further input for optimal cancer treatment.

Epigenetics in preimplantation mammalian development

Fertilization is a very dynamic period of comprehensive chromatin remodeling, from which two specialized cells result in a totipotent zygote. The formation of a totipotent cell requires extensive epigenetic remodeling that, although independent of modifications in the DNA sequence, still entails a profound cell-fate change, supported by transcriptional profile modifications. As a result of finely tuned interactions between numerous mechanisms, the goal of fertilization is to form a full healthy new individual. To avoid the persistence of alterations in epigenetic marks, the epigenetic information contained in each gamete is reset during early embryogenesis. Covalent modification of DNA by methylation, as well as posttranslational modifications of histone proteins and noncoding RNAs, appears to be the main epigenetic mechanisms that control gene expression. These allow different cells in an organism to express different transcription profiles, despite each cell containing the same DNA sequence. In the context of replacement of spermatic protamine with histones from the oocyte, active cell division, and specification of different lineages, active and passive mechanisms of epigenetic remodeling have been revealed as critical for editing the epigenetic profile of the early embryo. Importantly, redundant factors and mechanisms are likely in place, and only a few have been reported as critical for fertilization or embryo survival by the use of knockout models. The aim of this review is to highlight the main mechanisms of epigenetic remodeling that ensue after fertilization in mammals.

Sorafenib for advanced hepatocellular carcinoma (HCC): impact of rationing in the United Kingdom

BACKGROUND

The prognosis for hepatocellular carcinoma (HCC) is dependent upon tumour stage, performance status (PS), severity of underlying liver disease, and the availability of appropriate therapies. The unavailability of sorafenib may have a significantly adverse effect on the prognosis of UK patients with advanced HCC. During the study period, access to sorafenib was at the discretion of local health funding bodies, a process that may delay or deny access to the drug and that remains in place for Wales, Scotland, and Northern Ireland. Here, we attempt to address the impact of this system on patients with advanced HCC in the United Kingdom.

METHODS

This is a retrospective study performed in the two largest specialist hepatobiliary oncology units in the United Kingdom. Funding applications were made to local funding bodies for patients with advanced HCC for whom sorafenib was considered appropriate (advanced HCC not suitable for loco-regional therapies, compensated chronic liver disease, PS 0-2).

RESULTS

A total of 133 applications were made, of which 57 (43%) were approved and 76 (57%) declined. Demographics and prognostic factors were balanced between the two groups. This cohort had a number of adverse prognostic features: patients were predominantly PS 1-2; the majority had multifocal disease with the largest lesion being >5 cm; and macroscopic vascular invasion, metastases, and AFP >,000 ng ml(-1), were each present in one-third of cases. The median time from application to funding decision was 17 days (range 3-260 days). For the primary 'intention-to-treat' analysis, median overall survival was 4.1 months when funding was declined, and 9.5 months when funding was approved (hazard ratio (HR) 0.48; 95% CI 0.3186-0.7267; P=0.0005).

CONCLUSION

These data support the use of sorafenib for patients with advanced HCC as an effective intervention. In the United Kingdom, this applies to a relatively small group of patients, estimated to total ∼800 per year who, unfortunately, do not survive long enough to themselves lobby for the availability of this drug. These data provide a comparison of sorafenib with supportive care and demonstrate the potential detrimental impact on patient outcomes of rationing health-care resources on the basis of cost.

Immunity to the respiratory pathogen Bordetella pertussis

Bordetella pertussis causes whooping cough, a severe respiratory tract infection in infants and children, and also infects adults. Studies in murine models have shown that innate immune mechanisms involving dendritic cells, macrophages, neutrophils, natural killer cells, and antimicrobial peptides help to control the infection, while complete bacterial clearance requires cellular immunity mediated by T-helper type 1 (Th1) and Th17 cells. Whole cell pertussis vaccines (wP) are effective, but reactogenic, and have been replaced in most developed countries by acellular pertussis vaccines (aP). However, the incidence of pertussis is still high in many vaccinated populations; this may reflect sub-optimal, waning, or escape from immunity induced by current aP. Protective immunity generated by wP appears to be mediated largely by Th1 cells, whereas less efficacious alum-adjuvanted aP induce strong antibody Th2 and Th17 responses. New generation aP that induce Th1 rather than Th2 responses are required to improve vaccine efficacy and prevent further spread of B. pertussis.

Emerging strategies in the treatment of advanced hepatocellular carcinoma: the role of targeted therapies

Hepatocellular cancer (HCC) is the fifth most common cause of cancer worldwide and its incidence is increasing as a result of the dissemination of hepatitis B and C virus infection. Surgical resection and liver transplantation are considered the only cures for HCC, but benefit approximately 10-15% of patients. In addition, radiofrequency ablation may is potentially curative for patients' with small HCC. Some patients with unresectable disease confined to the liver may benefit from embolisation or chemoembolisation. In the presence of disease not amenable to loco-regional therapy, median survival is only a few months. Current systemic therapy with cytotoxic chemotherapy induces relatively few responses and has no clear survival benefit. Current interest is focussed on the potential role of targeted therapies based on the key aspects of molecular pathogenesis of HCC, most notably sorafenib, an oral multikinase inhibitor. Recent developments discussed in this article demonstrate the potential benefits of this drug which seems destined to become first-line therapy for advanced HCC.

Human-induced pluripotent stem cells produced under xeno-free conditions

Induced pluripotent stem cells (iPSCs) have radically advanced the field of regenerative medicine by making possible the production of patient-specific pluripotent stem cells from adult individuals. While cell differentiation protocols have been successfully developed, and animal models of human disease have proved that these cells have the potential to treat human diseases and conditions produced as a consequence of aging, degeneration, injury, and birth defects, logistical issues still remain unsolved and hamper the possibility of testing these cells in human clinical trials. Among them is the widely spread use of animal products for the generation and culture of iPSCs. We report here a xeno-free iPSC generation system that addresses all the steps of iPSCs production including the isolation and culture of adult skin fibroblasts, and iPSCs generation, expansion, and maintenance. iPSCs generated with a polycistronic lentiviral vector under xeno-free conditions displayed markers of pluripotency and gave rise to embryoid bodies (EBs) displaying indicators of the 3 primary germ layers. Xeno-free iPSCs injected into nude mice produced classic teratomas, and teratoma explants cultured under conditions favoring fibroblastic cells gave rise to cells morphologically indistinguishable from input cells. Protocols here described will facilitate the implementation of new cellular therapies for preclinical and clinical studies, potentially reducing the regulatory burden without compromising the differentiation potential of the cells.

Epirubicin, cisplatin and protracted venous infusion 5-Fluorouracil chemotherapy for advanced salivary adenoid cystic carcinoma

AIMS

Adenoid cystic carcinoma (ACC) is a rare tumour that usually arises in the salivary glands. Initial management is surgery often combined with adjuvant radiotherapy. Chemotherapy is reserved for treatment of symptomatic recurrence. We evaluated the combination of epirubicin, cisplatin and protracted venous infusion 5-fluorouracil (ECF) in the management of ACC.

MATERIALS AND METHODS

Patients referred for treatment of advanced, symptomatic ACC were considered. The drugs given were epirubicin 50 mg/m(2) 3-weekly, cisplatin 60 mg/m(2) 3-weekly and protracted venous infusion 5-fluorouracil 200 mg/m(2)/day.

RESULTS

Eight patients (median age 46 years) received a median of five cycles of chemotherapy. All patients had had previous surgery, seven had had previous radiotherapy and one had had previous chemotherapy. One patient showed a partial response (duration 34 months) and five showed stable disease (median duration 13.6 months [6.8-15.9+ months]). Median survival was 27 months (3.5-62.3 months).

CONCLUSIONS

The activity of ECF in ACC of the head and neck seems to be similar to the combination of cisplatin and 5-fluorouracil and single-agent epirubicin.

Targeted therapy in colorectal carcinoma: more than a theory

OBJECTIVE

The aim of this review was to examine clinical trial data reporting the use of targeted therapies in colorectal cancer.

METHOD

Candidate trials were identified by a comprehensive literature search.

RESULTS

The data on the use of targeted therapies; usually combined with chemotherapy in the treatment of colorectal cancer is accumulating rapidly. These new agents will increasingly become incorporated into standard treatment schedules.

CONCLUSION

Targeted therapy has moved rapidly from the laboratory to the clinic and is opening up potentially new and exciting areas for the development of the systemic treatment of colorectal cancer.

Oocyte spontaneous activation in different rat strains

Oocyte spontaneous activation (OSA) has been reported to occur during in vitro culture of ovulated rat oocytes. The objective of this study was to compare the rate of oocyte spontaneous activation and the level of maturation promoting factor (MPF) activity in oocytes from different strains. Twelve strains were selected from two commercial sources. Females were superovulated and oocytes collected 17 h after hCG injection. Denuded oocytes were cultured in M16 medium under oil at 37 degrees C and 5% CO(2) in air. The proportion of activated oocytes was determined after 6 h of in vitro culture. Data were compared by analysis of variance (ANOVA), considering each animal as an experimental unit. MPF activity was determined in oocytes from the different strains at 0, 1.5, and 3 h after oocyte collection. The log ratio of the MPF activity at 1.5 and 3 h relative to 0 hours for each animal was analyzed by ANOVA. While significant (p < 0.01) differences were observed between strains in the rate of OSA, there were no differences between strains in the level of MPF during the time points measured (p > 0.3).

Full developmental potential of mammalian preimplantation embryos is maintained after imaging using a spinning-disk confocal microscope

Fluorescent live imaging of cells and embryos at subcellular resolution poses significant challenges for biologists due to morbidity and mortality ensuing from phototoxicity. Here we report the use of a spinning-disk confocal microscope to image mouse and bovine preimplantation embryos without impairing their developmental potential. We also present data indicating that this imaging technique does not affect the functionality of subcellular components as assessed by reactive oxygen species (ROS) production, caspase activity, and DNA integrity. Spinning-disk confocal microscopy was also useful in determining cell number and allocation in transgenic bovine blastocysts. We conclude that this imaging method is suitable for monitoring preimplantation embryos.

Gastrazole (JB95008), a novel CCK2/gastrin receptor antagonist, in the treatment of advanced pancreatic cancer: results from two randomised controlled trials

Gastrin has been shown to be a growth stimulant in pancreatic cancer cells. Gastrazole is a potent and selective gastrin receptor antagonist. Two randomised blinded trials were conducted to assess the effect of gastrazole in advanced pancreatic cancer. Patients with biopsy-proven, inoperable pancreatic carcinoma were recruited. Trial A compared protracted venous infusion (PVI) gastrazole with PVI placebo, whereas trial B compared PVI gastrazole with PVI fluorouracil (5-FU). Eighteen patients were randomised in trial A. Gastrazole produced significantly better survival compared to placebo (median 7.9 months vs 4.5 months; 1-year survival: 33 vs 11%, respectively; log rank P=0.02). No difference in toxicity was seen between gastrazole and placebo, except central venous catheter and pump complications. Ninety-eight patients were randomised in trial B. No significant survival difference was detected between gastrazole and 5-FU (median: 3.6 vs 4.2 months; 1-year survival: 13.2 vs 26.2%, respectively; log rank P=0.42). Toxicity of gastrazole was mild with significantly less diarrhoea (P=0.03), stomatitis (P<0.001) and hand– foot syndrome (P<0.001) compared to 5-FU. Quality of life (QoL) assessment showed similar QoL between gastrazole and 5-FU at baseline and no significant differences occurred with treatment either between arms or within arms. Compared to placebo, patients with advanced pancreatic cancer treated with gastrazole appeared to live longer, albeit in a very small trial and will require confirmation with large-scale randomised data. However, it did not produce survival advantage over PVI 5-FU. Lack of toxicity for gastrazole may allow its combination with cytotoxic drugs.

Efficacy and tolerability of chemotherapy in elderly patients with advanced oesophago-gastric cancer: A pooled analysis of three clinical trials

The aim of this study was to determine the benefits of chemotherapy for oesophago-gastric cancer (OGC) in patients 70 years and above (> or =70) in comparison to younger patients. 1080 patients were enrolled into three randomised controlled trials assessing fluorouracil-based combination chemotherapy. Patients received either a platinum-containing regimen (ECF, MCF), PVI 5-FU (protracted venous infusion of 5-fluorouracil)+/-mitomycin C (MMC), or FAMTX. Of the 1080 patients randomised, 257 (23.8%) were aged > or =70 years. There were no significant differences in the incidence of grades 3/4 toxicity between the two cohorts. Objective and symptomatic response rates, failure-free and overall survival were not significantly different. In a multivariate analysis, independent prognostic factors for survival were performance status and locally advanced disease, not age. Patients > or =70 years with OGC obtained similar benefits from palliative chemotherapy with respect to symptomatic response, tumour regression and survival, without increased toxicities.

Phase III study of 5FU, etoposide and leucovorin (FELV) compared to epirubicin, cisplatin and 5FU (ECF) in previously untreated patients with advanced biliary cancer

The purpose of this study was to determine whether epirubicin, cisplatin and infused 5FU (ECF) improves overall survival (OS) compared to 5FU, etoposide and leucovorin (FELV) in patients with previously untreated advanced biliary cancer in a prospective randomised study. Patients were randomly assigned to receive epirubicin, cisplatin and infused 5FU ECF or bolus 5FU etoposide and leucovorin (FELV). The primary end point was OS with secondary end points of objective response rate (ORR), failure-free survival (FFS), quality of life (QOL) and toxicity. In all, 54 patients were recruited with 27 randomly assigned to each arm. The median OS for ECF was 9.02 months (95% confidence interval (CI): 6.46–11.51) and FELV 12.03 months (95% CI: 9.3–14.7), P=0.2059. Objective response rates were similar for both arms: ECF 19.2% (95% CI: 6.55–39.3); FELV 15% (95% CI: 3.2–37.9), P=0.72. There was significantly increased grade 3/4 neutropenia with FELV vs ECF (53.8 vs 29.5%, respectively, P=0.020). Symptom resolution was impressive for both regimens. This is the largest reported randomised study to date in this setting. ECF did not improve OS compared to FELV, but was associated with less acute toxicity. These data suggest that chemotherapy can prolong OS and achieve good symptomatic relief in advanced biliary cancer.

Mucinous histology predicts for reduced fluorouracil responsiveness and survival in advanced colorectal cancer

BACKGROUND

Mucinous carcinoma of the colon and rectum (mucinous CRC) is a histological subtype of colorectal adenocarcinoma for which there is little data on chemotherapy responsiveness. The purpose of this study was to investigate specifically the efficacy of fluorouracil-based first-line chemotherapy in patients with advanced mucinous CRC.

PATIENTS AND METHODS

All patients with advanced mucinous CRC enrolled in three prospective randomized trials evaluating infused 5-fluorouracil as first-line treatment were compared with patients with non-mucinous subtypes enrolled in the same trials in a case-control study. Prognostic factors associated with overall response rate (ORR), progression-free survival (PFS) and overall survival (OS) were identified using univariate and multivariate logistic and/or Cox proportional hazards analyses.

RESULTS

The study included 135 patients (45 cases and 90 controls). The response rates for cases and controls were 22% [95% confidence interval (CI), 11% to 38%] and 47% (95% CI, 36.1% to 58.2%), respectively (P=0.0058). Median OS for the mucinous CRC patients was 11.8 months (95% CI, 8.87-14.8) compared with 17.9 months (95% CI, 13.38-22.39) in the control group (univariate analysis, P=0.056); after correcting for significant prognostic factors by multivariate Cox regression analysis, P=0.0372 and hazard ratio (HR)=1.497 (1.02-2.19).

CONCLUSION

Patients with advanced mucinous CRC have a poorer response to fluorouracil-based first-line chemotherapy and reduced survival compared with patients with non-mucinous CRC.

The palliative benefits of MVP (mitomycin C, vinblastine and cisplatin) chemotherapy in patients with malignant mesothelioma

BACKGROUND

With the rising incidence of malignant mesothelioma (MM), it is important to optimise treatment to control symptoms, maintain quality of life and, if possible, prolong life. We have analysed prospectively collected data to evaluate a frequently used palliative chemotherapy regimen.

PATIENTS AND METHODS

Between October 1986 and May 2002 all patients with inoperable pleural mesothelioma were considered for treatment with MVP (mitomycin C 8 mg/m2 every 6 weeks, vinblastine 6 mg/m2 every 3 weeks and cisplatin 50 mg/m2 every 3 weeks) chemotherapy. Symptoms were assessed by physician assessment at baseline and after each cycle of chemotherapy.

RESULTS

One hundred and fifty patients were treated with MVP for mesothelioma. Forty-three per cent had a performance status (PS) 2 or worse. The response rate was 15.3%, with 68.6% having stable disease. Sixty-nine per cent reported an improvement in symptoms; in particular there were good responses for pain (71%), cough (62%) and dyspnoea (50%). The most common grade 3/4 toxicity was neutropenia (22%). Median overall survival was 7 months, with 1-year survival 31% and 2-year survival 11%. Median survival for patients with PS 0/1 was 10 months, and was 6 months for patients with PS 2/3. Poor prognostic factors in univariate analysis included poor PS, weight loss, mixed or sarcomatoid histology, low haemoglobin and high white blood cell count. Excluding pathological subtype, the prognostic significance of poor PS and weight loss were retained in multivariate analysis.

CONCLUSIONS

Palliation of symptoms in MM is achievable with current cisplatin-based treatments.

A randomised comparison between 6 months of bolus fluorouracil/leucovorin and 12 weeks of protracted venous infusion fluorouracil as adjuvant treatment in colorectal cancer

BACKGROUND

We performed a multicentre randomised trial to compare the efficacy and toxicity of 12 weeks of protracted venous infusion (PVI) 5-fluorouracil (5-FU) against the standard bolus monthly regimen of 5-FU/leucovorin (LV) given for 6 months as adjuvant treatment in colorectal cancer (CRC).

PATIENTS AND METHODS

Patients with curatively resected stage II and III CRC were randomly assigned to 5-FU/LV [5-FU 425 mg/m(2) intravenously (i.v.) and LV 20 mg/m(2) i.v. bolus days 1-5 every 28 days for 6 months] or to PVI 5-FU (300 mg/m(2)/day for 12 weeks).

RESULTS

Between 1993 and 2003, 801 eligible patients were randomised to 5-FU/LV (n=404) or PVI 5-FU (n=397). With a median follow-up of 5.3 years, 231 relapses and 220 deaths have been observed. Five-year relapse-free survival (RFS) was 66.7% [95% confidence interval (CI) 61.6% to 71.3%] and 73.3% (95% CI 68.4% to 77.6%) with bolus 5-FU/LV and PVI 5-FU, respectively [hazard ratio (HR) 0.8; 95% CI 0.62-1.04; P=0.10]. Five-year overall survival (OS) was 71.5% (95% CI 66.4% to 75.9%) and 75.7% (95% CI 70.8% to 79.9%) with bolus 5-FU/LV and PVI 5-FU, respectively (HR 0.79; 95% CI 0.61-1.03; P=0.083). There was a significant survival advantage for patients starting adjuvant chemotherapy within 8 weeks (P=0.044). Significantly less diarrhoea, stomatitis, nausea and vomiting, alopecia, lethargy, and neutropenia (all with P <0.0001) were seen with PVI 5-FU.

CONCLUSIONS

There was no OS difference between the two arms, although PVI 5-FU was associated with a trend towards better RFS and OS compared with bolus 5-FU/LV, as well as significantly less toxicity. Based on our results, the probability of 12 weeks of PVI 5-FU being inferior to 6 months of bolus 5-FU/LV is extremely low (P <0.005), and therefore shorter duration of adjuvant treatment should be explored further.

Elderly patients with fluoropyrimidine and thymidylate synthase inhibitor-resistant advanced colorectal cancer derive similar benefit without excessive toxicity when treated with irinotecan monotherapy

Elderly patients are recommended to have a reduced starting dose (300 mg m⁻² once every 3 weeks) of irinotecan monotherapy. The aims of this analysis are to compare toxicity and survival according to age, performance status (PS), gender and prior radical pelvic radiotherapy (RT). The primary end points were overall survival and an irinotecan-specific toxicity composite end point (TCE) defined as the occurrence of grade 3 or 4 diarrhoea, neutropenia, febrile neutropenia, fever, infection or nausea and vomiting. Between 1997 and 2003, 339 eligible patients with advanced colorectal cancer (CRC) progressing on or within 24 weeks of completing fluoropyrimidine-based chemotherapy were prospectively registered in a multicentre randomised trial. All patients commenced irinotecan at 350 mg m⁻² once every 3 weeks. There were no differences in proportions of patients developing TCE by age (<70 vs ⩾70 : 37.8 vs 45.8%; P=0.218), PS (0–1 vs 2 : 39.3 vs 41.5%; P=0.793) or prior RT (RT vs no RT : 45.1 vs 38.5%; P=0.377). Males experienced more toxicity than females (44.3 vs 32.6%; P=0.031), but this was not significant after controlling for other co-variates (P=0.06). Patients aged ⩾70 had similar objective responses (11.1 vs 9%; P=0.585) and survival (median 9.4 vs 9 months; log rank P=0.74) compared to younger patients. Elderly patients derive the same benefit without experiencing more toxicity with second-line irinotecan treatment for advanced CRC. Our data do not support the recommendation to reduce the starting dose for the elderly patients.

Phase II study of capecitabine and mitomycin C as first-line treatment in patients with advanced colorectal cancer

This study was designed to assess the safety and efficacy of capecitabine and mitomycin C (MMC) in previously untreated patients with advanced colorectal cancer (CRC). Patients received capecitabine 2500 mg m² day 1, orally divided in two doses of 1250 mg m⁻² in the morning and evening for 14 days every 21 days and MMC 7 mg m⁻² (maximum total dose 14 mg) as an intravenous bolus every 6 weeks for a total of four courses. The median age was 70 years (range 24–85) and the majority of patients (86.9%) were of performance status 1/2. The most common metastatic site was liver. In all, 84 patients were assessable for response. The overall response rate was 38% (95% CI: 27.7–49.3) and a further 33.3% of patients achieved stable disease over 12 weeks. There was good symptom resolution ranging from 64 to 86%. Grade 3/4 toxicity was as follows: hand–foot syndrome 19.7%; diarrhoea 10%; neutropenia 2.4%; infection 2.3%. Capecitabine and MMC have shown encouraging activity with a favourable toxicity profile, a convenient administration schedule, and could be considered for patients deemed unsuitable for oxaliplatin and irinotecan combinations.

Estradiol benzoate given 0 or 24h after the end of a progestagen treatment in postpartum suckled beef cows

The objective of Experiment 1 was to compare the effects of estradiol benzoate (EB) given 0 or 24h after the end of a progestagen treatment on ovulation and CL formation in anestrous cows. Twenty cows were treated with an intravaginal sponge containing 250 mg of medroxiprogesterone acetate (MPA). At sponge insertion, each cow received 3 mg EB and 10 mg MPA im. At device removal, cows received 0.7 mg EB either at that time (EB0) or 24h later (EB24). Ultrasound examinations and blood sampling to determine plasma progesterone concentrations were performed to detect ovulation and CL formation. Ovulation occurred in 77.8 and 81.8% cows in the EB0 and EB24 groups, respectively. Diameter of the ovulatory follicle (EB0 = 10.9 +/- 0.5mm; EB24 = 12.1 +/- 0.8 mm; P = 0.26) and the interval from sponge removal to ovulation (median = 3 days; P = 0.64) did not differ between treatments. Among the cows that ovulated (n = 16), short-lived CL were present in 2/7 and 2/9 cows in the EB0 and EB24 groups, respectively. Plasma progesterone concentrations and CL area did not differ between treatments (P > 0.05). In Experiment 2, cows were treated with the same protocol as in Experiment 1, but at sponge withdrawal all cows received 250 microg cloprostenol and timed artificial insemination (TAI) was performed 48 h after sponge removal. In Replicate 1 (n = 204 multiparous cows), pregnancy rates were 45.0 and 47.5% for EB0 and EB24, respectively (P > 0.05). In Replicate 2 (n = 69 primiparous cows) pregnancy rate did not differ between EB0 and EB24 (51.4% versus 52.9%). In conclusion, EB given 0 or 24h after the end of a progestagen treatment had the same effect on ovulation rate, time to ovulation, diameter of the ovulatory follicle, incidence of short-lived CL, luteal tissue area, and plasma progesterone concentrations of normal lifespan CL, and pregnancy rate after TAI in suckled beef cows.

Do patients with weight loss have a worse outcome when undergoing chemotherapy for lung cancers?

To examine whether weight loss at presentation influences outcome in patients who received chemotherapy for lung cancer or mesothelioma. Multivariate analysis of prospectively collected data 1994–2001. Data were available for age, gender, performance status, histology, stage, response, toxicity, progression-free and overall survival. The outcomes of patients with or without weight loss treated with chemotherapy for small cell lung cancer (SCLC; n=290), stages III and IV non-small-cell lung cancer (NSCLC; n=418), or mesothelioma (n=72) were compared. Weight loss was reported by 59, 58 and 76% of patients with SCLC, NSCLC and mesothelioma, respectively. Patients with weight loss and NSCLC (P=0.003) or mesothelioma (P=0.05) more frequently failed to complete at least three cycles of chemotherapy. Anaemia as a toxicity occurred significantly more frequently in NSCLC patients with weight loss (P=0.0003). The incidence of other toxicities was not significantly affected by weight loss. NSCLC patients with weight loss had fewer symptomatic responses (P=0.001). Mesothelioma patients with weight loss had fewer symptomatic (P=0.03) and objective responses (P=0.05). Weight loss was an independent predictor of shorter overall survival for patients with SCLC (P=0.003, relative risk (RR)=1.5), NSCLC (P=0.009, RR=1.33) and mesothelioma (P=0.03, RR=1.92) and an independent predictor of progression-free survival in patients with SCLC (P=0.01, RR=1.43). In conclusion, weight loss as a symptom of lung cancer predicts for toxicity from treatment and shorter survival.

Twelve weeks of protracted venous infusion of fluorouracil (5-FU) is as effective as 6 months of bolus 5-FU and folinic acid as adjuvant treatment in colorectal cancer

We performed a multicentre randomised trial to compare the efficacy and toxicity of 12 weeks of 5-fluorouracil (5-FU) delivered by protracted intravenous infusion (PVI 5-FU) against the standard bolus regimen of 5-FU and folinic acid (5-FU/FA) given for 6 months as adjuvant treatment in colorectal cancer. A total of 716 patients with curatively resected Dukes' B or C colorectal cancer were randomised to 5-FU/FA (5-FU 425 mg m(-2) i.v. and FA 20 mg m(-2) i.v. bolus days 1-5 every 28 days for 6 months) or to PVI 5-FU alone (300 mg m(-2) day for 12 weeks). With a median follow-up of 19.8 months, 133 relapses and 77 deaths have been observed. Overall survival did not differ significantly (log rank P=0.764) between patients receiving 5-FU/FA and PVI 5-FU (3-year survival 83.2 vs 87.9%, respectively). Patients in the 5-FU/FA group had significantly worse relapse-free survival (RFS, log rank P=0.023) compared to those receiving PVI 5-FU (3-year RFS, 68.6 vs 80%, respectively). Grades 3-4 neutropenia, diarrhoea, stomatitis and severe alopecia were significantly less (P<0.0001) and global quality of life scores significantly better (P&<0.001) for patients in the PVI 5-FU treatment arm. In conclusion, infused 5-FU given over 12 weeks resulted in similar survival to bolus 5-FU and FA over a 6 month period, but with significantly less toxicity.

Inhibition of Kirsten-ras expression in human colorectal cancer using rationally selected Kirsten-ras antisense oligonucleotides

Kirsten-ras is frequently mutated in colorectal cancers and may be an important therapeutic target, particularly because we have previously shown that acquisition of a mutation is associated with a poorer outcome. Understanding the role of Kirsten-ras and the consequences of inhibiting its activity or expression will contribute to our comprehension of colorectal cancer biology and may help to rationalize the choice of molecular targets suitable for therapeutic manipulation. Therefore we undertook a simple screen, incubating a library of oligonucleotides with Kirsten-ras mRNA and RNase H to identify an antisense oligonucleotide that effectively inhibited Kirsten-ras expression. We show for the first time in a human colon cancer cell line that inhibition of Kirsten-ras expression inhibits constitutive phosphorylation of Erk1/2, but not c-Akt, suggesting that in these cells constitutive phosphorylation of Erk 1/2 is dependent upon Kirsten-ras. Successful inhibition of Kirsten-ras had little effect on cell number or cell death and there was no evidence for accumulation of cells in any particular phase of the cell cycle. Kirsten-ras inhibition significantly reduced secretion of VEGF-A165 into the culture medium. Gene expression profiling by microarray detected altered expression of a number of genes. Of particular interest for future studies was the altered expression of genes encoding products involved in protein trafficking and the potential effects of these changes on cell adhesion. Our results suggest that, at least in this model, Kirsten-ras may contribute to malignancy predominantly through effects on angiogenesis, invasion, and metastasis, and that therapies directed at Kirsten-ras, including antisense approaches, may have particular utility through these mechanisms.

Results and implications of the Royal Marsden and other tamoxifen chemoprevention trials

A pilot chemoprevention study from the Royal Marsden Hospital in the United Kingdom demonstrated that tamoxifen could be administered safely to healthy women. This led to the establishment of multicenter trials, including the National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 and Italian National Cancer Institute trials. An interim analysis of the Royal Marsden Hospital trial did not detect a preventive effect. The Italian trial concurred with the Royal Marsden Hospital trial. In contrast, the larger NSABP study detected a 49% reduction in the incidence of breast cancer with tamoxifen chemoprevention. Possible reasons for the different results are examined and the implications for tamoxifen chemoprevention are discussed.

Antisense treatment directed against mutated Ki-ras in human colorectal adenocarcinoma

BACKGROUND

Kirsten ras (Ki-ras) mutations are common in gastrointestinal cancer and one codon 12 mutation, glycine to valine, is particularly aggressive in colorectal cancer.

AIMS

To investigate if this valine point mutation could be targeted with antisense oligonucleotides and to determine the efficacy of any antisense/mRNA interaction.

METHODS

Twenty nine antisense oligonucleotides were screened against target and control Ki-ras RNA in a cell free system and against target and control cell lines in culture.

RESULTS

The activity and specificity of the oligonucleotides varied. Results for the individual oligonucleotides were consistent in a cell free model and in cell culture using two different uptake promoters. Only one oligonucleotide was specific in its cleavage of target Ki-ras mRNA in the cell free system and appeared specific in cell culture, although changes in Ki-ras mRNA and protein expression following a single treatment could not be detected. Experiments in the cell free system showed that the point mutation is relatively inaccessible to oligonucleotides. Other sites on the Ki-ras RNA molecule, away from the point mutation, can be targeted more effectively.

CONCLUSIONS

Successful targeting of the clinically relevant Ki-ras point mutation with antisense oligonucleotides is difficult because of RNA structure at the mutated site and is inefficient compared with other sites on the Ki-ras mRNA.