Ribosomal protein control of hematopoietic stem cell transformation through direct, non-canonical regulation of metabolism.

We report here that expression of the ribosomal protein, RPL22, is frequently reduced in human myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML); reduced RPL22 expression is associated with worse outcomes. Mice null for Rpl22 display characteristics of an MDS-like syndrome and develop leukemia at an accelerated rate. Rpl22-deficient mice also display enhanced hematopoietic stem cell (HSC) self-renewal and obstructed differentiation potential, which arises not from reduced protein synthesis but from increased expression of the Rpl22 target, ALOX12, an upstream regulator of fatty acid oxidation (FAO). The increased FAO mediated by Rpl22-deficiency also persists in leukemia cells and promotes their survival. Altogether, these findings reveal that Rpl22 insufficiency enhances the leukemia potential of HSC via non-canonical de-repression of its target, ALOX12, which enhances FAO, a process that may serve as a therapeutic vulnerability of Rpl22 low MDS and AML leukemia cells. Highlights: RPL22 insufficiency is observed in MDS/AML and is associated with reduced survivalRpl22-deficiency produces an MDS-like syndrome and facilitates leukemogenesisRpl22-deficiency does not impair global protein synthesis by HSCRpl22 controls leukemia cell survival by non-canonical regulation of lipid oxidation eTOC: Rpl22 controls the function and transformation potential of hematopoietic stem cells through effects on ALOX12 expression, a regulator of fatty acid oxidation.

Misidentification of MLL3 and other mutations in cancer due to highly homologous genomic regions.

The MLL3 gene has been shown to be recurrently mutated in many malignancies including in families with acute myeloid leukemia. We demonstrate that many MLL3 variant calls made by exome sequencing are false positives due to misalignment to homologous regions, including a region on chr21, and can only be validated by long-range PCR. Numerous other recurrently mutated genes reported in COSMIC and TCGA databases have pseudogenes and cannot also be validated by conventional short read-based sequencing approaches. Genome-wide identification of pseudogene regions demonstrates that frequency of these homologous regions is increased with sequencing read lengths below 200 bps. To enable identification of poor quality sequencing variants in prospective studies, we generated novel genome-wide maps of regions with poor mappability that can be used in variant calling algorithms. Taken together, our findings reveal that pseudogene regions are a source of false-positive mutations in cancers.

Herpes simplex virus of the nose masquerading as invasive fungal sinusitis: A pediatric case series.

The management of invasive fungal sinusitis differs greatly from the management of herpes simplex virus (HSV) of the nose in immunocompromised patients. However, the diagnosis may be uncertain and a delay in treatment can lead to mortality. Here we describe the successful medical management of a series of immunocompromised pediatric patients with HSV lesions of the nose with the initial concern for invasive fungal sinusitis. The diagnosis of HSV herpes was supported by positive polymerase chain reaction (PCR) testing of the nasal lesion. To our knowledge, these are the first cases described in the pediatric literature, emphasizing the need to include this entity on the differential.

A case of KMT2A-SEPT9 fusion-associated acute megakaryoblastic leukemia.

Acute megakaryoblastic leukemia (AMKL) constitutes ∼5%-15% of cases of non-Down syndrome AML in children, and in the majority of cases, chimeric oncogenes resulting from recurrent gene rearrangements are identified. Based on these rearrangements, several molecular subsets have been characterized providing important prognostic information. One such subset includes a group of patients with translocations involving the KMT2A gene, which has been associated with various fusion partners in patients with AMKL. Here we report the molecular findings of a 2-yr-old girl with AMKL and t(11;17)(q23;25) found to have a KMT2A-SEPT9 fusion identified through targeted RNA sequencing. A KMT2A-SEPT9 fusion in this subset of patients has not previously been reported.

Exopolysaccharide production in Caulobacter crescentus: A resource allocation trade-off between protection and proliferation.

Complex and interacting selective pressures can produce bacterial communities with a range of phenotypes. One measure of bacterial success is the ability of cells or populations to proliferate while avoiding lytic phage infection. Resistance against bacteriophage infection can occur in the form of a metabolically expensive exopolysaccharide capsule. Here, we show that in Caulobacter crescentus, presence of an exopolysaccharide capsule provides measurable protection against infection from a lytic paracrystalline S-layer bacteriophage (CR30), but at a metabolic cost that reduces success in a phage-free environment. Carbon flux through GDP-mannose 4,6 dehydratase in different catabolic and anabolic pathways appears to mediate this trade-off. Together, our data support a model in which diversity in bacterial communities may be maintained through variable selection on phenotypes utilizing the same metabolic pathway.

High resolution integrative analysis reveals widespread genetic and epigenetic changes after chronic in-vitro acid and bile exposure in Barrett's epithelium cells.

Barrett's epithelium (BE) is a premalignant condition resulting from chronic gastroesophageal reflux that may progress to esophageal adenocarcinoma (EAC). Early intervention holds promise in preventing BE progression. However, identification of high-risk BE patients remains challenging due to inadequate biomarkers for early diagnosis. We investigated the effect of prolonged chronic acid and bile exposure on transcriptome, methylome, and mutatome of cells in an in-vitro BE carcinogenesis (BEC) model. Twenty weeks acid and bile exposed cells from the BEC model (BEC20w) were compared with their naïve predecessors HiSeq Illumina based RNA sequencing was performed on RNA from both the cells for gene expression and mutational analysis. HELP Tagging Assay was performed for DNA methylation analysis. Ingenuity pathway, Gene Ontology, and KEGG PATHWAY analyses were then performed on datasets. Widespread aberrant genetic and epigenetic changes were observed in the BEC20w cells. Combinatorial analyses revealed 433 from a total of 863 downregulated genes had accompanying hypermethylation of promoters. Simultaneously, 690 genes from a total of 1,492 were upregulated with accompanying promoter hypomethylation. In addition, 763 mutations were identified on 637 genes. Ingenuity pathway analysis, Gene Ontology, and KEGG PATHWAY analyses associated the genetic and epigenetic changes in BEC20w cells with cellular and biological functions. Integration of high resolution comparative analyses of naïve BAR-T and BEC20w cells revealed striking genetic and epigenetic changes induced by chronic acid and bile exposure that may disrupt normal cellular functions and promote carcinogenesis. This novel study reveals several potential targets for future biomarkers and therapeutic development.

Day One Talk: parent preferences when learning that their child has cancer.

PURPOSE: The discussion that occurs between a pediatric oncologist and a family when they first learn about their child's new diagnosis of cancer is known as the "Day One Talk." Few studies have addressed parent preferences when learning that their child has been diagnosed with cancer. The objective of this study is to assess what information parents of children with newly diagnosed cancer believe is important to learn during the Day One Talk. METHODS: In this cross-sectional study, a survey tool based on expert opinion was created to assess parents' views of components of the Day One Talk including its content, length, and setting, as well as whether the child should be present for the initial talk and which staff should be present for the talk. RESULTS: Sixty-two parents of children with newly diagnosed cancer participated. Ninety-seven percent believed that the Day One Talk is extremely important. Ninety percent believed that the word "cancer" should be used during the Day One Talk. Seventy-seven percent believed that the pediatric oncologist should provide specific numbers regarding cure rates for the patient's diagnosis. Eighty-four percent of parents do not believe that children younger than 14 should be present. CONCLUSIONS: These results suggest that parents of children with cancer have certain preferences regarding the Day One Talk. When conducting the Day One Talk, providers should elicit parent preferences regarding these issues in order to best meet families' needs.

miR-21 mediates hematopoietic suppression in MDS by activating TGF-ß signaling.

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis that leads to peripheral cytopenias. We observed that SMAD7, a negative regulator of transforming growth factor-beta (TGF-ß) receptor-I kinase, is markedly reduced in MDS and leads to ineffective hematopoiesis by overactivation of TGF-ß signaling. To determine the cause of SMAD7 reduction in MDS, we analyzed the 3'UTR of the gene and determined that it contains a highly conserved putative binding site for microRNA-21. We observed significantly elevated levels of miR-21 in MDS marrow samples when compared with age-matched controls. miR-21 was shown to directly bind to the 3'UTR of SMAD7 and reduce its expression in hematopoietic cells. Next, we tested the role of miR-21 in regulating TGF-ß signaling in a TGF-ß-overexpressing transgenic mouse model that develops progressive anemia and dysplasia and thus serves as a model of human bone marrow failure. Treatment with a chemically modified miR-21 inhibitor led to significant increases in hematocrit and led to an increase in SMAD7 expression in vivo. Inhibition of miR-21 also led to an increase in erythroid colony formation from primary MDS bone marrow progenitors, demonstrating its ability in stimulating hematopoiesis in vitro. Taken together, these studies demonstrate the role of miR-21 in regulating overactivated TGF-ß signaling in MDS.

Alterations in the ribosomal machinery in cancer and hematologic disorders.

Ribosomes are essential components of the protein translation machinery and are composed of more than 80 unique large and small ribosomal proteins. Recent studies show that in addition to their roles in protein translation, ribosomal proteins are also involved in extra-ribosomal functions of DNA repair, apoptosis and cellular homeostasis. Consequently, alterations in the synthesis or functioning of ribosomal proteins can lead to various hematologic disorders. These include congenital anemias such as Diamond Blackfan anemia and Shwachman Diamond syndrome; both of which are associated with mutations in various ribosomal genes. Acquired uniallelic deletion of RPS14 gene has also been shown to lead to the 5q syndrome, a distinct subset of MDS associated with macrocytic anemia. Recent evidence shows that specific ribosomal proteins are overexpressed in liver, colon, prostate and other tumors. Ribosomal protein overexpression can promote tumorigenesis by interactions with the p53 tumor suppressor pathway and also by direct effects on various oncogenes. These data point to a broad role of ribosome protein alterations in hematologic and oncologic diseases.

Sialoblastoma- long-term follow-up and remission for a rare salivary malignancy.

Sialoblastoma is a rare salivary neoplasm which presents either congenitally or during early infancy. It was originally considered a benign neoplasm, however a number of reported cases have documented locoregional recurrence and distant metastases. Currently, there is no consensus on the appropriate treatment for this neoplasm. We report on long term follow-up of a patient with metastatic sialoblastoma, and a brief discussion of the possible treatment modalities currently being considered.