Long-term intermittent caloric restriction remodels the gut microbiota in mice genetically prone to breast cancer.

OBJECTIVES: Gut microbiota dysbiosis is among the risk factors for breast cancer development, together with genetic background and dietary habits. However, caloric restriction has been shown to remodel the gut microbiota and slow tumor growth. Here, we investigated whether the gut microbiota mediates the preventive effects of long-term chronic or intermittent caloric restriction on breast cancer predisposition. METHODS: 10-week-old transgenic breast cancer-prone mice were randomly assigned to dietary groups (ad libitum, chronic caloric restriction, and intermittent caloric restriction groups) and fed up to week 81. Stool samples were collected at weeks 10 (baseline), 17 (young), 49 (adult), and 81 (old). 16S rRNA gene sequencing was performed to identify the gut microbiota profile of the different groups. In order to investigate the breast cancer gut microbiota profile within genetically predisposed individuals regardless of diet, mammary tumor-bearing mice and mammary tumor-free but genetically prone mice were selected from the ad libitum group (n = 6). RESULTS: Intermittent caloric restriction increased the microbial diversity of adult mice and modified age-related compositional changes. A total of 13 genera were differentially abundant over time. Pathogenic Mycoplasma was enriched in the re-feeding period of the old intermittent caloric restriction group compared with baseline. Furthermore, mammary tumor-free mice showed shared gut microbiota characteristics with mammary tumor-bearing mice, suggesting an early link between genetic predisposition, gut microbiota, and breast cancer development. CONCLUSIONS: Our study revealed the role of gut microbes in the preventive effects of caloric restriction against breast cancer development, implying the significance of diet and microbiome interplay.

From Alpha-Thalassemia Trait to NPRL3-Related Epilepsy: A Genomic Diagnostic Odyssey.

Introduction: The NPRL3 gene is a critical component of the GATOR1 complex, which negatively regulates the mTORC1 pathway, essential for neurogenesis and brain development. Located on chromosome 16p13.3, NPRL3 is situated near the α-globin gene cluster. Haploinsufficiency of NPRL3, either by deletion or a pathogenic variant, is associated with a variable phenotype of focal epilepsy, with or without malformations of cortical development, with known decreased penetrance. Case Description: This work details the diagnostic odyssey of a neurotypical 10-year-old boy who presented at age 2 with unusual nocturnal episodes and a history of microcytic anemia, as well as a review of the existing literature on NPRL3-related epilepsy, with an emphasis on individuals with deletions who also present with α-thalassemia trait. The proband's episodes were mistaken for gastroesophageal reflux disease for several years. He had molecular testing for his α-thalassemia trait and was noted to carry a deletion encompassing the regulatory region of the α-thalassemia gene cluster. Following the onset of overt focal motor seizures, genetic testing revealed a heterozygous loss of NPRL3, within a 106 kb microdeletion on chromosome 16p13.3, inherited from his mother. This deletion encompassed the entire NPRL3 gene, which overlaps the regulatory region of the α-globin gene cluster, giving him the dual diagnosis of NPRL3-related epilepsy and α-thalassemia trait. Brain imaging postprocessing showed left hippocampal sclerosis and mid-posterior para-hippocampal focal cortical dysplasia, leading to the consideration of epilepsy surgery. Conclusions: This case underscores the necessity of early and comprehensive genetic assessments in children with epilepsy accompanied by systemic features, even in the absence of a family history of epilepsy or a developmental delay. Recognizing phenotypic overlaps is crucial to avoid diagnostic delays. Our findings also highlight the impact of disruptions in regulatory regions in genetic disorders: any individual with full gene deletion of NPRL3 would have, at a minimum, α-thalassemia trait, due to the presence of the major regulatory element of α-globin genes overlapping the gene's introns.

Clinico-biological refinement of BCL11B-related disorder and identification of an episignature: A series of 20 unreported individuals.

PURPOSE: BCL11B-related disorder (BCL11B-RD) arises from rare genetic variants within the BCL11B gene, resulting in a distinctive clinical spectrum encompassing syndromic neurodevelopmental disorder, with or without intellectual disability, associated with facial features and impaired immune function. This study presents an in-depth clinico-biological analysis of 20 newly reported individuals with BCL11B-RD, coupled with a characterization of genome-wide DNA methylation patterns of this genetic condition. METHODS: Through an international collaboration, clinical and molecular data from 20 individuals were systematically gathered, and a comparative analysis was conducted between this series and existing literature. We further scrutinized peripheral blood DNA methylation profile of individuals with BCL11B-RD, contrasting them with healthy controls and other neurodevelopmental disorders marked by established episignature. RESULTS: Our findings unveil rarely documented clinical manifestations, notably including Rubinstein-Taybi-like facial features, craniosynostosis, and autoimmune disorders, all manifesting within the realm of BCL11B-RD. We refine the intricacies of T cell compartment alterations of BCL11B-RD, revealing decreased levels naive CD4+ T cells and recent thymic emigrants while concurrently observing an elevated proportion of effector-memory expressing CD45RA CD8+ T cells (TEMRA). Finally, a distinct DNA methylation episignature exclusive to BCL11B-RD is unveiled. CONCLUSION: This study serves to enrich our comprehension of the clinico-biological landscape of BCL11B-RD, potentially furnishing a more precise framework for diagnosis and follow-up of individuals carrying pathogenic BCL11B variant. Moreover, the identification of a unique DNA methylation episignature offers a valuable diagnosis tool for BCL11B-RD, thereby facilitating routine clinical practice by empowering physicians to reevaluate variants of uncertain significance within the BCL11B gene.

Broadening the phenotypic and molecular spectrum of FINCA syndrome: Biallelic NHLRC2 variants in 15 novel individuals.

FINCA syndrome [MIM: 618278] is an autosomal recessive multisystem disorder characterized by fibrosis, neurodegeneration and cerebral angiomatosis. To date, 13 patients from nine families with biallelic NHLRC2 variants have been published. In all of them, the recurrent missense variant p.(Asp148Tyr) was detected on at least one allele. Common manifestations included lung or muscle fibrosis, respiratory distress, developmental delay, neuromuscular symptoms and seizures often followed by early death due to rapid disease progression.Here, we present 15 individuals from 12 families with an overlapping phenotype associated with nine novel NHLRC2 variants identified by exome analysis. All patients described here presented with moderate to severe global developmental delay and variable disease progression. Seizures, truncal hypotonia and movement disorders were frequently observed. Notably, we also present the first eight cases in which the recurrent p.(Asp148Tyr) variant was not detected in either homozygous or compound heterozygous state.We cloned and expressed all novel and most previously published non-truncating variants in HEK293-cells. From the results of these functional studies, we propose a potential genotype-phenotype correlation, with a greater reduction in protein expression being associated with a more severe phenotype.Taken together, our findings broaden the known phenotypic and molecular spectrum and emphasize that NHLRC2-related disease should be considered in patients presenting with intellectual disability, movement disorders, neuroregression and epilepsy with or without pulmonary involvement.

Dual BRCA1 and BRCA2 pathogenic variants in an adolescent with syndromic intellectual disability.

Pathogenic variants in the BRCA1 and BRCA2 genes are associated with increased risk for breast and ovarian cancers. Concurrent mutations in both genes in the same individual are rare but pose specific challenges when identified, usually through multigene panel testing or infrequently from a genome-wide analysis, such as whole-exome sequencing (WES). We present a 15-year-old female patient with syndromic intellectual disability whose exome reanalysis identified secondary findings of pathogenic BRCA1 and BRCA2 variants, both inherited paternally. We discuss the significant challenges posed by this finding in genetic counseling and cancer risk management of an adolescent with nonverbal intellectual disability, as well as the impact on their family. This rare case highlights the potential increased diagnostic yield of whole exome sequencing reanalysis and the consequences of secondary medically actionable results in a pediatric patient.

Novel findings and expansion of phenotype in a mosaic RASopathy caused by somatic KRAS variants.

Mosaic KRAS variants and other RASopathy genes cause oculoectodermal, encephalo-cranio-cutaneous lipomatosis, and Schimmelpenning-Feuerstein-Mims syndromes, and a spectrum of vascular malformations, overgrowth and other associated anomalies, the latter of which are only recently being characterized. We describe eight individuals in total (six unreported cases and two previously reported cases) with somatic KRAS variants and variably associated features. Given the findings of somatic overgrowth (in seven individuals) and vascular or lymphatic malformations (in eight individuals), we suggest mosaic RASopathies (mosaic KRAS variants) be considered in the differential diagnosis for individuals presenting with asymmetric overgrowth and lymphatic or vascular anomalies. We expand the association with embryonal tumors, including the third report of embryonal rhabdomyosarcoma, as well as novel findings of Wilms tumor and nephroblastomatosis in two individuals. Rare or novel findings in our series include the presence of epilepsy, polycystic kidneys, and T-cell deficiency in one individual, and multifocal lytic bone lesions in two individuals. Finally, we describe the first use of targeted therapy with a MEK inhibitor for an individual with a mosaic KRAS variant. The purposes of this report are to expand the phenotypic spectrum of mosaic KRAS-related disorders, and to propose possible mechanisms of pathogenesis, and surveillance of its associated findings.

Tatton-Brown-Rahman syndrome: Six individuals with novel features.

Tatton-Brown Rahman syndrome (TBRS) is an overgrowth-intellectual disability syndrome caused by heterozygous variants in DNMT3A. Seventy-eight individuals have been reported with a consistent phenotype of somatic overgrowth, mild to moderate intellectual disability, and similar dysmorphisms. We present six individuals with TBRS, including the youngest individual thus far reported, first individual to be diagnosed with tumor testing and two individuals with variants at the Arg882 domain, bringing the total number of reported cases to 82. Patients reported herein have additional clinical features not previously reported in TBRS. One patient had congenital diaphragmatic hernia. One patient carrying the recurrent p.Arg882His DNMT3A variant, who was previously reported as having a phenotype due to a truncating variant in the CLTC gene, developed a ganglioneuroblastoma at 18 months and T-cell lymphoblastic lymphoma at 6 years of age. Four patients manifested symptoms suggestive of autonomic dysfunction, including central sleep apnea, postural orthostatic hypotension, and episodic vasomotor instability in the extremities. We discuss the molecular and clinical findings in our patients with TBRS in context of existing literature.

Broad spectrum of neuropsychiatric phenotypes associated with white matter disease in PTEN hamartoma tumor syndrome.

White matter lesions have been described in patients with PTEN hamartoma tumor syndrome (PHTS). How these lesions correlate with the neurocognitive features associated with PTEN mutations, such as autism spectrum disorder (ASD) or developmental delay, has not been well established. We report nine patients with PTEN mutations and white matter changes on brain magnetic resonance imaging (MRI), eight of whom were referred for reasons other than developmental delay or ASD. Their clinical presentations ranged from asymptomatic macrocephaly with normal development/intellect, to obsessive compulsive disorder, and debilitating neurological disease. To our knowledge, this report constitutes the first detailed description of PTEN-related white matter changes in adult patients and in children with normal development and intelligence. We present a detailed assessment of the neuropsychological phenotype of our patients and discuss the relationship between the wide array of neuropsychiatric features and observed white matter findings in the context of these individuals.

The effect of tomatine on metastasis related matrix metalloproteinase (MMP) activities in breast cancer cell model.

Breast cancer is one of the most common malignancies in women and metastasis is the cause of morbidity and mortality in patients. In the development of metastasis, the matrix metalloproteinase (MMP) family has a very important role in tumor development. MMP-2 and MMP-9 work together for extracellular matrix (ECM) cleavage to increase migration. Tomatine is a secondary metabolite that has a natural defense role against plants, fungi, viruses and bacteria that are synthesized from tomato. In addition, tomatine is also known that it breaks down the cell membrane and is a strong inhibitor in human cancer cells. In this study, it was aimed to evaluate the effect of tomatine on cytotoxicity, apoptosis and matrix metalloproteinase inhibition in MCF-7 cell lines. Human breast cancer cell line (MCF-7) was used as a cell line. In MCF-7 cells, the IC50 dose of tomatine was determined to be 7.07µM. According to the control cells, apoptosis increased 3.4 fold in 48thh. Activation of MMP-2, MMP-9 and MMP-9\NGAL has been shown to decrease significantly in cells treated with tomatine by gelatin zymography compared to the control. As a result, matrix metalloproteinase activity and cell proliferation were suppressed by tomatine and this may provide support in treatment methods.

Expression profiling of RE1-silencing transcription factor (REST), REST corepressor 1 (RCOR1), and Synapsin 1 (SYN1) genes in human gliomas.

PURPOSE: The repressor element 1 (RE-1) silencing transcription factor (REST) is a transcription factor which represses the expression of neuronal differentiation-related genes including SYN1 gene. CoREST, encoded by RCOR1 gene, binds to the REST protein for remodeling of chromatin structure. Although there is a relation among REST, RCOR1, and SYN1 genes, the role of these genes in glioma tumors is still unclear. In this study, expressions of REST, RCOR1, and SYN1 genes were detected in primary cultures derived from tumor samples of diffuse astrocytoma (DA), anaplastic oligodendroglioma (AO), and glioblastoma multiforme (GBM) cases. METHODS: Expression profiles were analysed by RT-qPCR and the copy number variations were examined with qPCR in primary cultures. ChIP assay was performed to show binding characteristics of REST and CoREST proteins on promoter region of SYN1 gene. RESULTS: Means of relative expression for REST were as follows: 0.7898, 0.7606, and 0.7318 in DA, AO, and GBM groups, respectively. For RCOR1, expression means in DA, AO, and GBM groups were 0.7203, 0.7334, and 0.7230, respectively. SYN1 expression means were as follows: 0.3936, 0.3192, and 0.3197 in DA, AO, and GBM groups, respectively. Neither gain nor loss of copy numbers were detected for REST and RCOR1 genes in all groups. Copy loss for SYN1 was detected in primary culture of a DA case. REST and CoREST presented positive precipitation pattern on promoter region of SYN1 gene. CONCLUSIONS: Expressions of REST and RCOR1 genes may downregulate SYN1 expression in gliomas. Low expression pattern of SYN1 may maintain cancer stem-like phenotype which contributes to development of gliomas.

Analysis of dysregulated long non-coding RNA expressions in glioblastoma cells.

Long non coding RNAs (lncRNAs) are associated with various biological roles such as embryogenesis, stem cell biology, cellular development and present specific tissue expression profiles. Aberrant expression of lncRNAs are thought to play a critical role in the progression and development of various cancer types, including gliomas. Glioblastomas (GBM) are common and malignant primary brain tumours. Brain cancer stem cells (BCSC) are isolated from both low and high-grade tumours in adults and children, by cell fraction which express neuronal stem cell surface marker CD133. The purpose of this study was to investigate the expression profiles of lncRNAs in brain tumour cells and determine its potential biological function. For this purpose, U118MG-U87MG; GBM stem cell series were used. Human parental brain cancer cells were included as the control group; the expressions of disease related human lncRNA profiles were studied by LightCycler 480 real-time PCR. Expression profiles of 83 lncRNA genes were analyzed for a significant dysregulation, compared to the control cells. Among lncRNAs, 51 lncRNA genes down-regulated, while 8 lncRNA genes were up-regulated. PCAT-1 (-2.36), MEG3 (-5.34), HOTAIR (-2.48) lncRNAs showed low expression in glioblastoma compared to the human (parental) brain cancer stem cells, indicating their role as tumour suppressor genes on gliomas. As a result, significant changes for anti-cancer gene expressions were detected with disease-related human lncRNA array plates. Identification of novel target genes may lead to promising developments in human brain cancer treatment.

Effect of Hereditary Hemochromatosis Gene H63D and C282Y Mutations on Iron Overload in Sickle Cell Disease Patients.

OBJECTIVE: Hemochromatosis is an autosomal recessive disease that is one of the most important reasons for iron overload. Sickle cell disease is a hemoglobinopathy that occurs as a result of a homozygous mutation in the hemoglobin gene. Erythrocyte transfusion is frequently used in the treatment of this disease. Iron overload as a result of transfusion is important in the mortality and morbidity of sickle cell anemia patients as well as in other hemoglobinopathies. In this study, the effect of hemochromatosis gene (HFE) p.H63D and p.C282Y mutations on transfusion-related cardiac and liver iron overload in sickle cell disease patients who carry homozygous hemoglobin S mutation has been investigated. MATERIALS AND METHODS: This is a prospective single-center cross-sectional study in patients with homozygous hemoglobin S mutation between the years 2008 and 2013. The patients were divided into two groups. The first group (group A, n=31) was receiving chelation therapy and the second group (group B, n=13) was not. Direct and indirect iron loads were analyzed by magnetic resonance imaging and biochemically, respectively. HFE gene mutations were analyzed by polymerase chain reaction-restriction fragment length polymorphism method. Statistical analyses were performed by independent samples t-test. RESULTS: p.H63D mutation was detected in 10 (32.3%) patients in group A and in only 1 patient (7.7%) in group B. When the 2 groups were compared for iron overload, iron deposition in the liver was significantly higher in group B (p=0.046). In addition, in group A, iron deposition was significantly higher in HFE mutation carriers compared to patients without the mutation (p=0.05). CONCLUSION: Results of this study showed that HFE gene mutations are important in iron deposition in the liver in patients with sickle cell disease.

Genistein-induced mir-23b expression inhibits the growth of breast cancer cells.

AIM OF THE STUDY: Genistein, an isoflavonoid, plays roles in the inhibition of protein tyrosine kinase phosphorylation, induction of apoptosis, and cell differentiation in breast cancer. This study aims to induce cellular stress by exposing genistein to determine alterations of miRNA expression profiles in MCF-7 cells. MATERIAL AND METHODS: XTT assay and trypan blue dye exclusion assays were performed to examine the cytotoxic effects of genistein treatment. Expressions of miRNAs were quantified using Real-Time Online RT-PCR. RESULTS: The IC50 dose of genistein was 175 µM in MCF-7 cell, line and the cytotoxic effect of genistein was detected after 48 hours. miR-23b was found to be up-regulated 56.69 fold following the treatment of genistein. It was found that miR-23b was upregulated for MCF-7 breast cancer cells after genistein treatment. CONCLUSIONS: Up-regulated ex-expression of miR-23b might be a putative biomarker for use in the therapy of breast cancer patients. miR-23b up-regulation might be important in terms of response to genistein.

Brain malformations in a patient with deletion 2p16.1: A refinement of the phenotype to BCL11A.

Microdeletions of 2p15-16.1 have been reported in 15 patients with a recognizable syndrome of dysmorphic features, intellectual disability and microcephaly. Facial features include telecanthus, short palpebral fissures, epicanthal folds, a broad nasal root, smooth and long philtrum and large ears. Brain malformations can be observed in this syndrome and include hypoplasia of the corpus callosum and a simplified cortical gyral pattern. Case reports have narrowed the critical region of the neurodevelopmental phenotype to a region that spans the B-cell CLL/lymphoma 11A (BCL11A) gene. Here we present a 3-year-old normocephalic girl with moderate development delay and dysmorphic features including a prominent forehead, telecanthus, depressed nasal bridge, thin upper vermilion and a small chin. Magnetic resonance imaging shows enlargement of the lateral, third and fourth ventricles and hypoplastic corpus callosum, cerebellar vermis and pons. Array CGH revealed a 0.875 Mb de novo deletion at 2p16.1 that includes only BCL11A. The moderate delays, hypoplastic and dysmorphic corpus callosum and hippocampi and the facial features are in keeping with the previously described 2p15-16.1 microdeletion syndrome. However, hypoplasia of the pons and cerebellum are not commonly recognized features and are reminiscent of the brain malformations observed in individuals with a mutation in CASK. CASK is known to interact with BCL11A in the normal growth of axons. This case report highlights the role of BCL11A in 2p15-16.1 microdeletion syndrome and the unique phenotype suggests a common pathway for BCL11A and other genes in neurodevelopment.

Mast cell development and function in the zebrafish.

The many advantages of the zebrafish model provide a unique opportunity to integrate the tools of developmental embryology, transgenesis, and functional assays to elucidate the molecular pathways underlying hematopoiesis and for modeling human blood diseases. These methodologies have recently been applied to the zebrafish mast cell lineage and have resulted in a better understanding of vertebrate mast cell biology. By employing whole-mount in situ hybridization alone and in combination with co-localization approaches, fluorescence-activated cell sorting (FACS), and morpholino gene knockdown studies, new insights into early mast cell transcriptional regulation and ontogeny have been exposed in vivo. Transgenic strategies have permitted the modeling of human mast cell diseases, like systemic mastocytosis in zebrafish, which can subsequently be exploited for high-throughput chemical screens to identify potential therapies in these conditions. Mast cell functional assays have been adapted to zebrafish providing the opportunity to utilize this model for interrogating the cellular players in innate and adaptive immunity and as a live animal readout for drug responses in allergic and inflammatory reactions. These techniques are detailed in the following chapter.

Synergistic effect of ponatinib and epigallocatechin-3-gallate induces apoptosis in chronic myeloid leukemia cells through altering expressions of cell cycle regulatory genes.

PURPOSE: Ponatinib (P) has been used for the treatment of chronic myeloid leukemia (CML) and it is known that inhibition of BCR-ABL fusion protein by ponatinib induces apoptosis of CML cells. Epigallocatechin-3-gallate (EGCG), which is a polyphenol in green tea, induces apoptosis in different types of cancer cells. The purpose of this study was to determine the cytotoxic and apoptotic effects of ponatinib and EGCG combination in K562 CML cell line. This study also aimed to detect alterations of the expression levels of cell cycle-regulation related genes after ponatinib and EGCG combination in K562 CML cell line. METHODS: The cytotoxic effects of the compounds on K562 cells were determined in a time-and dose-dependent manner by using WST-1 analysis. The combination index (CI) isobologram was used to analyze the data. Apoptotic effects of P-EGCG were defined by flow cytometry and gene expressions were detected by RT-qPCR. RESULTS: IC50values of ponatinib and EGCG were 87.13 nM and 50µM, respectively. CI value of the P-EGCG was 0.658 and the combination showed synergistic effect (ED90 value: 28.39 nM ponatinib, 117.12 µg/ml EGCG). Ponatinib, EGCG and P-EGCG induced apoptosis compared to control cells. CyclinD1 and CDC25A were downregulated by P-EGCG by 2.49 and 2.63-fold, respectively. TGF-ß2 was upregulated by 4.57-fold. CONCLUSION: EGCG possesses cytotoxic and apoptotic properties and may cooperate with the growth inhibiting activity of ponatinib synergistically against CML cells. P-EGCG mediated apoptosis might be associated with upregulation of TGF-ß2 gene and downregulation of cyclinD1 and CDC25A genes.

A transgenic zebrafish model expressing KIT-D816V recapitulates features of aggressive systemic mastocytosis.

Systemic mastocytosis (SM) is a rare myeloproliferative disease without curative therapy. Despite clinical variability, the majority of patients harbour a KIT-D816V mutation, but efforts to inhibit mutant KIT with tyrosine kinase inhibitors have been unsatisfactory, indicating a need for new preclinical approaches to identify alternative targets and novel therapies in this disease. Murine models to date have been limited and do not fully recapitulate the most aggressive forms of SM. We describe the generation of a transgenic zebrafish model expressing the human KIT-D816V mutation. Adult fish demonstrate a myeloproliferative disease phenotype, including features of aggressive SM in haematopoeitic tissues and high expression levels of endopeptidases, consistent with SM patients. Transgenic embryos demonstrate a cell-cycle phenotype with corresponding expression changes in genes associated with DNA maintenance and repair, such as reduced dnmt1. In addition, epcam was consistently downregulated in both transgenic adults and embryos. Decreased embryonic epcam expression was associated with reduced neuromast numbers, providing a robust in vivo phenotypic readout for chemical screening in KIT-D816V-induced disease. This study represents the first zebrafish model of a mast cell disease with an aggressive adult phenotype and embryonic markers that could be exploited to screen for novel agents in SM.

Design of polyethylene glycol-polyethylenimine nanocomplexes as non-viral carriers: mir-150 delivery to chronic myeloid leukemia cells.

MicroRNAs (miRNAs) are acknowledged as indispensable regulators relevant in many biological processes, and they have been pioneered as therapeutic targets for curing disease. miRNAs are single-stranded, small (19-22 nt) regulatory non-coding RNAs whose deregulation of expression triggers human cancers, including leukemias, mainly through dysregulation of expression of leukemia genes. miRNAs can function as tumour suppressors (suppressing malignant potential) or oncogenes (activating malignant potential) like actors of complex diseases. To address the issue of overcoming instability and low transfection efficiency in vitro, the polyethylene glycol-polyethyleneimine (PEG-PEI) nanoparticle was used as non-viral vector carrier for miR-150 transfection, which is downregulated in chronic myeloid leukemia. PEG-PEI [PEG(550)3 -g-PEI(1800) ]/miRNA nanocomplexes were synthesised and characterised by particle size distribution (PSD), polydispersity index (PDI) and zeta potential, surface charge, their cytotoxicity, and transfection efficiency. Interaction with human leukemia cells (K-562 and KU812) and control cells NCI-BL2347 with them has been investigated. The transfection efficiency of PEG-PEI/miRNA at N/P 26 rose 6.7-fold above the control by qRT-PCR. The size of homogenous nanocomplexes (PBI < 0.5) was 160.8 ± 11 nm. The data indicate that PEG-PEI may be an encouraging non-viral carrier for altering miRNA expression in the treatment of chronic myeloid leukemia, with many advantages such as relatively high miRNA transfection efficiency and low cytotoxicity.

Zebrafish xenografts as a tool for in vivo studies on human cancer.

The zebrafish has become a powerful vertebrate model for genetic studies of embryonic development and organogenesis and increasingly for studies in cancer biology. Zebrafish facilitate the performance of reverse and forward genetic approaches, including mutagenesis and small molecule screens. Moreover, several studies report the feasibility of xenotransplanting human cells into zebrafish embryos and adult fish. This model provides a unique opportunity to monitor tumor-induced angiogenesis, invasiveness, and response to a range of treatments in vivo and in real time. Despite the high conservation of gene function between fish and humans, concern remains that potential differences in zebrafish tissue niches and/or missing microenvironmental cues could limit the relevance and translational utility of data obtained from zebrafish human cancer cell xenograft models. Here, we summarize current data on xenotransplantation of human cells into zebrafish, highlighting the advantages and limitations of this model in comparison to classical murine models of xenotransplantation.

The zebrafish reveals dependence of the mast cell lineage on Notch signaling in vivo.

We used the opportunities afforded by the zebrafish to determine upstream pathways regulating mast cell development in vivo and identify their cellular origin. Colocalization studies demonstrated zebrafish notch receptor expression in cells expressing carboxypeptidase A5 (cpa5), a zebrafish mast cell-specific marker. Inhibition of the Notch pathway resulted in decreased cpa5 expression in mindbomb mutants and wild-type embryos treated with the γ-secretase inhibitor, Compound E. A series of morpholino knockdown studies specifically identified notch1b and gata2 as the critical factors regulating mast cell fate. Moreover, hsp70::GAL4;UAS::nicd1a transgenic embryos overexpressing an activated form of notch1, nicd1a, displayed increased cpa5, gata2, and pu.1 expression. This increase in cpa5 expression could be reversed and reduced below baseline levels in a dose-dependent manner using Compound E. Finally, evidence that cpa5 expression colocalizes with lmo2 in the absence of hematopoietic stem cells revealed that definitive mast cells initially delineate from erythromyeloid progenitors. These studies identify a master role for Notch signaling in vertebrate mast cell development and establish developmental origins of this lineage. Moreover, these findings postulate targeting the Notch pathway as a therapeutic strategy in mast cell diseases.