396 research outputs found

    Phase 1 trial of rituximab, lenalidomide, and ibrutinib in previously untreated follicular lymphoma: Alliance A051103

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    Chemoimmunotherapy in follicular lymphoma is associated with significant toxicity. Targeted therapies are being investigated as potentially more efficacious and tolerable alternatives for this multiply-relapsing disease. Based on promising activity with rituximab and lenalidomide in previously untreated follicular lymphoma (overall response rate [ORR] 90%-96%) and ibrutinib in relapsed disease (ORR 30%-55%), the Alliance for Clinical Trials in Oncology conducted a phase 1 trial of rituximab, lenalidomide, and ibrutinib. Previously untreated patients with follicular lymphoma received rituximab 375 mg/m 2 on days 1, 8, 15, and 22 of cycle 1 and day 1 of cycles 4, 6, 8, and 10; lenalidomide as per cohort dose on days 1 to 21 of 28 for 18 cycles; and ibrutinib as per cohort dose daily until progression. Dose escalation used a 3+3 design from a starting dose level (DL) of lenalidomide 15 mg and ibrutinib 420 mg (DL0) to DL2 (lenalidomide 20 mg, ibrutinib 560 mg). Twenty-two patients were enrolled; DL2 was determined to be the recommended phase II dose. Although no protocol-defined dose-limiting toxicities were reported, a high incidence of rash was observed (all grades 82%, grade 3 36%). Eleven patients (50%) required dose reduction, 7 because of rash. The ORR for the entire cohort was 95%, and the 12-month progression-free survival was 80% (95% confidence interval, 57%-92%). Five patients developed new malignancies; 3 had known risk factors before enrollment. Given the increased toxicity and required dose modifications, as well as the apparent lack of additional clinical benefit to the rituximab-lenalidomide doublet, further investigation of the regimen in this setting seems unwarranted. The study was registered with www.ClinicalTrials.gov as #NCT01829568

    Activation of PyMT in β Cells Induces Irreversible Hyperplasia, but Oncogene-Dependent Acinar Cell Carcinomas When Activated in Pancreatic Progenitors

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    It is unclear whether the cellular origin of various forms of pancreatic cancer involves transformation or transdifferentiation of different target cells or whether tumors arise from common precursors, with tumor types determined by the specific genetic alterations. Previous studies suggested that pancreatic ductal carcinomas might be induced by polyoma middle T antigen (PyMT) expressed in non-ductal cells. To ask whether PyMT transforms and transdifferentiates endocrine cells toward exocrine tumor phenotypes, we generated transgenic mice that carry tetracycline-inducible PyMT and a linked luciferase reporter. Induction of PyMT in β cells causes β-cell hyperplastic lesions that do not progress to malignant neoplasms. When PyMT is de-induced, β cell proliferation and growth cease; however, regression does not occur, suggesting that continued production of PyMT is not required to maintain the viable expanded β cell population. In contrast, induction of PyMT in early pancreatic progenitor cells under the control of Pdx1 produces acinar cell carcinomas and β-cell hyperplasia. The survival of acinar tumor cells is dependent on continued expression of PyMT. Our findings indicate that PyMT can induce exocrine tumors from pancreatic progenitor cells, but cells in the β cell lineage are not transdifferentiated toward exocrine cell types by PyMT; instead, they undergo oncogene-dependent hyperplastic growth, but do not require PyMT for survival

    ExprTarget: An Integrative Approach to Predicting Human MicroRNA Targets

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    Variation in gene expression has been observed in natural populations and associated with complex traits or phenotypes such as disease susceptibility and drug response. Gene expression itself is controlled by various genetic and non-genetic factors. The binding of a class of small RNA molecules, microRNAs (miRNAs), to mRNA transcript targets has recently been demonstrated to be an important mechanism of gene regulation. Because individual miRNAs may regulate the expression of multiple gene targets, a comprehensive and reliable catalogue of miRNA-regulated targets is critical to understanding gene regulatory networks. Though experimental approaches have been used to identify many miRNA targets, due to cost and efficiency, current miRNA target identification still relies largely on computational algorithms that aim to take advantage of different biochemical/thermodynamic properties of the sequences of miRNAs and their gene targets. A novel approach, ExprTarget, therefore, is proposed here to integrate some of the most frequently invoked methods (miRanda, PicTar, TargetScan) as well as the genome-wide HapMap miRNA and mRNA expression datasets generated in our laboratory. To our knowledge, this dataset constitutes the first miRNA expression profiling in the HapMap lymphoblastoid cell lines. We conducted diagnostic tests of the existing computational solutions using the experimentally supported targets in TarBase as gold standard. To gain insight into the biases that arise from such an analysis, we investigated the effect of the choice of gold standard on the evaluation of the various computational tools. We analyzed the performance of ExprTarget using both ROC curve analysis and cross-validation. We show that ExprTarget greatly improves miRNA target prediction relative to the individual prediction algorithms in terms of sensitivity and specificity. We also developed an online database, ExprTargetDB, of human miRNA targets predicted by our approach that integrates gene expression profiling into a broader framework involving important features of miRNA target site predictions

    Mosaic Chromosomal alterations in Blood across ancestries Using Whole-Genome Sequencing

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    Megabase-scale mosaic chromosomal alterations (mCAs) in blood are prognostic markers for a host of human diseases. Here, to gain a better understanding of mCA rates in genetically diverse populations, we analyzed whole-genome sequencing data from 67,390 individuals from the National Heart, Lung, and Blood Institute Trans-Omics for Precision Medicine program. We observed higher sensitivity with whole-genome sequencing data, compared with array-based data, in uncovering mCAs at low mutant cell fractions and found that individuals of European ancestry have the highest rates of autosomal mCAs and the lowest rates of chromosome X mCAs, compared with individuals of African or Hispanic ancestry. Although further studies in diverse populations will be needed to replicate our findings, we report three loci associated with loss of chromosome X, associations between autosomal mCAs and rare variants in DCPS, ADM17, PPP1R16B and TET2 and ancestry-specific variants in ATM and MPL with mCAs in cis

    Determinants of Mosaic Chromosomal alteration Fitness

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    Clonal hematopoiesis (CH) is characterized by the acquisition of a somatic mutation in a hematopoietic stem cell that results in a clonal expansion. These driver mutations can be single nucleotide variants in cancer driver genes or larger structural rearrangements called mosaic chromosomal alterations (mCAs). The factors that influence the variations in mCA fitness and ultimately result in different clonal expansion rates are not well understood. We used the Passenger-Approximated Clonal Expansion Rate (PACER) method to estimate clonal expansion rate as PACER scores for 6,381 individuals in the NHLBI toPMed cohort with gain, loss, and copy-neutral loss of heterozygosity mCAs. Our mCA fitness estimates, derived by aggregating per-individual PACER scores, were correlated (

    A shared MHC supertype motif emerges by convergent evolution in macaques and mice, but is totally absent in human MHC molecules

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    The SIV-infected rhesus macaque (Macaca mulatta) is the most established model of AIDS disease systems, providing insight into pathogenesis and a model system for testing novel vaccines. The understanding of cellular immune responses based on the identification and study of Major Histocompatibility Complex (MHC) molecules, including their MHC:peptide-binding motif, provides valuable information to decipher outcomes of infection and vaccine efficacy. Detailed characterization of Mamu-B*039:01, a common allele expressed in Chinese rhesus macaques, revealed a unique MHC:peptide-binding preference consisting of glycine at the second position. Peptides containing a glycine at the second position were shown to be antigenic from animals positive for Mamu-B*039:01. A similar motif was previously described for the Dd mouse MHC allele, but for none of the human HLA molecules for which a motif is known. Further investigation showed that one additional macaque allele, present in Indian rhesus macaques, Mamu-B*052:01, shares this same motif. These “G2” alleles were associated with the presence of specific residues in their B pocket. This pocket structure was found in 6% of macaque sequences but none of 950 human HLA class I alleles. Evolutionary studies using the “G2” alleles points to common ancestry for the macaque sequences, while convergent evolution is suggested when murine and macaque sequences are considered. This is the first detailed characterization of the pocket residues yielding this specific motif in nonhuman primates and mice, revealing a new supertype motif not present in humans

    Type 2 Diabetes Modifies the association of Cad Genomic Risk Variants With Subclinical atherosclerosis

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    BACKGROUND: Individuals with type 2 diabetes (T2D) have an increased risk of coronary artery disease (CAD), but questions remain about the underlying pathology. Identifying which CAD loci are modified by T2D in the development of subclinical atherosclerosis (coronary artery calcification [CAC], carotid intima-media thickness, or carotid plaque) may improve our understanding of the mechanisms leading to the increased CAD in T2D. METHODS: We compared the common and rare variant associations of known CAD loci from the literature on CAC, carotid intima-media thickness, and carotid plaque in up to 29 670 participants, including up to 24 157 normoglycemic controls and 5513 T2D cases leveraging whole-genome sequencing data from the Trans-Omics for Precision Medicine program. We included first-order T2D interaction terms in each model to determine whether CAD loci were modified by T2D. The genetic main and interaction effects were assessed using a joint test to determine whether a CAD variant, or gene-based rare variant set, was associated with the respective subclinical atherosclerosis measures and then further determined whether these loci had a significant interaction test. RESULTS: Using a Bonferroni-corrected significance threshold of CONCLUSIONS: These results highlight T2D as an important modifier of rare variant associations in CAD loci with CAC

    A novel member of the let-7 microRNA family is associated with developmental transitions in filarial nematode parasites

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    Background: Filarial nematodes are important pathogens in the tropics transmitted to humans via the bite of blood sucking arthropod vectors. The molecular mechanisms underpinning survival and differentiation of these parasites following transmission are poorly understood. microRNAs are small non-coding RNA molecules that regulate target mRNAs and we set out to investigate whether they play a role in the infection event. Results: microRNAs differentially expressed during the early post-infective stages of Brugia pahangi L3 were identified by microarray analysis. One of these, bpa-miR-5364, was selected for further study as it is upregulated ~12-fold at 24 hours post-infection, is specific to clade III nematodes, and is a novel member of the let-7 family, which are known to have key developmental functions in the free-living nematode Caenorhabditis elegans. Predicted mRNA targets of bpa-miR-5364 were identified using bioinformatics and comparative genomics approaches that relied on the conservation of miR-5364 binding sites in the orthologous mRNAs of other filarial nematodes. Finally, we confirmed the interaction between bpa-miR-5364 and three of its predicted targets using a dual luciferase assay. Conclusions: These data provide new insight into the molecular mechanisms underpinning the transmission of third stage larvae of filarial nematodes from vector to mammal. This study is the first to identify parasitic nematode mRNAs that are verified targets of specific microRNAs and demonstrates that post-transcriptional control of gene expression via stage-specific expression of microRNAs may be important in the success of filarial infection
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