Notch signaling expands a pre-malignant pool of T-cell acute lymphoblastic leukemia clones without affecting leukemia-propagating cell frequency

NOTCH1 pathway activation contributes to the pathogenesis of over 60% of T-cell acute lymphoblastic leukemia (T-ALL). While Notch is thought to exert the majority of its effects through transcriptional activation of Myc, it also likely has independent roles in T-ALL malignancy. Here, we utilized a zebrafish transgenic model of T-ALL, where Notch does not induce Myc transcription, to identify a novel Notch gene expression signature that is also found in human T-ALL and is regulated independently of Myc. Cross-species microarray comparisons between zebrafish and mammalian disease identified a common T-ALL gene signature, suggesting that conserved genetic pathways underlie T-ALL development. Functionally, Notch expression induced a significant expansion of pre-leukemic clones; however, a majority of these clones were not fully transformed and could not induce leukemia when transplanted into recipient animals. Limiting-dilution cell transplantation revealed that Notch signaling does not increase the overall frequency of leukemia-propagating cells (LPCs), either alone or in collaboration with Myc. Taken together, these data indicate that a primary role of Notch signaling in T-ALL is to expand a population of pre-malignant thymocytes, of which a subset acquire the necessary mutations to become fully transformed LPCs

Deregulation of the EGFR/PI3K/PTEN/Akt/mTORC1 pathway in breast cancer: possibilities for therapeutic intervention

The EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway plays prominent roles in malignant transformation, prevention of apoptosis, drug resistance and metastasis. The expression of this pathway is frequently altered in breast cancer due to mutations at or aberrant expression of: HER2, ERalpha, BRCA1, BRCA2, EGFR1, PIK3CA, PTEN, TP53, RB as well as other oncogenes and tumor suppressor genes. In some breast cancer cases, mutations at certain components of this pathway (e.g., PIK3CA) are associated with a better prognosis than breast cancers lacking these mutations. The expression of this pathway and upstream HER2 has been associated with breast cancer initiating cells (CICs) and in some cases resistance to treatment. The anti-diabetes drug metformin can suppress the growth of breast CICs and herceptin-resistant HER2+ cells. This review will discuss the importance of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway primarily in breast cancer but will also include relevant examples from other cancer types. The targeting of this pathway will be discussed as well as clinical trials with novel small molecule inhibitors. The targeting of the hormone receptor, HER2 and EGFR1 in breast cancer will be reviewed in association with suppression of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway.USAMRMC {[}BC022276]; Intramural RECDA Award; Italian Association for Cancer Research (AIRC); MIUR-PRIN; Italian MIUR-FIRB Accordi di Programma; Italian ``Ministero dell'Istruzione, dell'Universita e della Ricerca (Ministry for Education, Universities and Research) - FIRB-MERIT {[}RBNE08YYBM]; Italian Ministry of Economy and Finance; Italian Ministry of Health, Ricerca Finalizzata Stemness; MIUR FIRB {[}RBAP11ZJFA\_001]; CRO; Italian Association for Cancer Research, (AIRC) (RM PI); Italian Association for Cancer Research, (AIRC) {[}MCO10016]; Italian Ministry of Health; Regione Friuli Venezia-Giuli

Genome-wide identification of microRNAs regulating cholesterol and triglyceride homeostasis

Genome-wide association studies (GWASs) have linked genes to various pathological traits. However, the potential contribution of regulatory noncoding RNAs, such as microRNAs (miRNAs), to a genetic predisposition to pathological conditions has remained unclear. We leveraged GWAS meta-analysis data from >188,000 individuals to identify 69 miRNAs in physical proximity to single-nucleotide polymorphisms (SNPs) associated with abnormal levels of circulating lipids. Several of these miRNAs (miR-128-1, miR-148a, miR-130b, and miR-301b) control the expression of key proteins involved in cholesterol-lipoprotein trafficking, such as the low-density lipoprotein (LDL) receptor (LDLR) and the ATP-binding cassette A1 (ABCA1) cholesterol transporter. Consistent with human liver expression data and genetic links to abnormal blood lipid levels, overexpression and antisense targeting of miR-128-1 or miR-148a in high-fat diet–fed C57BL/6J and Apoe-null mice resulted in altered hepatic expression of proteins involved in lipid trafficking and metabolism, and in modulated levels of circulating lipoprotein-cholesterol and triglycerides. Taken together, these findings support the notion that altered expression of miRNAs may contribute to abnormal blood lipid levels, predisposing individuals to human cardiometabolic disorders.Organismic and Evolutionary Biolog

4. TITLE AND SUBTITLE DNA Repair and Checkpoint Genes as NF1 Modifiers

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Ctf Meeting 2012: Translation Of The Basic Understanding Of The Biology And Genetics Of Nf1, Nf2, And Schwannomatosis Toward The Development Of Effective Therapies

The neurofibromatoses (NF) are autosomal dominant genetic disorders that encompass the rare diseases NF1, NF2, and schwannomatosis. The NFs affect more people worldwide than Duchenne muscular dystrophy and Huntington\u27s disease combined. NF1 and NF2 are caused by mutations of known tumor suppressor genes (NF1 and NF2, respectively). For schwannomatosis, although mutations in SMARCB1 were identified in a subpopulation of schwannomatosis patients, additional causative gene mutations are still to be discovered. Individuals with NF1 may demonstrate manifestations in multiple organ systems, including tumors of the nervous system, learning disabilities, and physical disfigurement. NF2 ultimately can cause deafness, cranial nerve deficits, and additional severe morbidities caused by tumors of the nervous system. Unmanageable pain is a key finding in patients with schwannomatosis. Although today there is no marketed treatment for NF-related tumors, a significant number of clinical trials have become available. In addition, significant preclinical efforts have led to a more rational selection of potential drug candidates for NF trials. An important element in fueling this progress is the sharing of knowledge. For over 20 years the Children\u27s Tumor Foundation has convened an annual NF Conference, bringing together NF professionals to share novel findings, ideas, and build collaborations. The 2012 NF Conference held in New Orleans hosted over 350 NF researchers and clinicians. This article provides a synthesis of the highlights presented at the conference and as such, is a state-of-the-field for NF research in 2012. © 2014 Wiley Periodicals, Inc

DNA Sequences in the Promoter Region of the NF1 Gene Are Highly Conserved between Human and Mouse

The gene for type 1 neurofibromatosis (NF1) is most highly expressed in brain and spinal cord, although low levels of mRNA can be found in nearly all tissues. As a first step in investigating the regulation of NF1 gene expression, we have cloned and sequenced the promoter regions of the human and mouse NF1 genes and mapped the transcriptional start sites in both species. We report here that the 5' ends of the human and murine NF1 genes are highly conserved. While no discernable TATA or CCAAT box sequences are seen, transcription initiates at identical sites in both species, 484 nucleotides upstream of the ATG initiation codon in the human gene. The human and mouse NF1 genes share particularly high sequence homology (95%) between nucleotides -33 and +261 and contain several perfectly conserved transcription factor binding site motifs, including a cAMP response element, several AP2 consensus binding sites, and a serum response element. The high conservation of these sequences indicates that they are likely to be significant in the regulation of NF1 gene expression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31556/1/0000482.pd

MdMyb93 is a regulator of suberin deposition in russeted apple fruit skins.

A comparison of the transcriptomes of russeted vs nonrusseted apple skins previously highlighted a tight relationship between a gene encoding an MYB-type transcription factor, MdMYB93, and some key suberin biosynthetic genes. The present work assesses the role of this transcription factor in the suberization process. A phylogenetic analysis of MdMYB93 and Arabidopsis thaliana MYBs was performed and the function of MdMYB93 was further investigated using Agrobacterium-mediated transient overexpression in Nicotiana benthamiana leaves. An RNA-Seq analysis was performed to highlight the MdMYB93-regulated genes. Ultraperformance liquid chromatography-triple time-of-flight (UPLC-TripleTOF) and GC-MS were used to investigate alterations in phenylpropanoid, soluble-free lipid and lipid polyester contents. A massive accumulation of suberin and its biosynthetic precursors in MdMYB93 agroinfiltrated leaves was accompanied by a remobilization of phenylpropanoids and an increased amount of lignin precursors. Gene expression profiling displayed a concomitant alteration of lipid and phenylpropanoid metabolism, cell wall development, and extracellular transport, with a large number of induced transcripts predicted to be involved in suberin deposition. The present work supports a major role of MdMYB93 in the regulation of suberin deposition in russeted apple skins, from the synthesis of monomeric precursors, their transport, polymerization, and final deposition as suberin in primary cell wall

Dissecting hematopoietic and renal cell heterogeneity in adult zebrafish at single-cell resolution using RNA sequencing

Recent advances in single-cell, transcriptomic profiling have provided unprecedented access to investigate cell heterogeneity during tissue and organ development. In this study, we used massively parallel, single-cell RNA sequencing to define cell heterogeneity within the zebrafish kidney marrow, constructing a comprehensive molecular atlas of definitive hematopoiesis and functionally distinct renal cells found in adult zebrafish. Because our method analyzed blood and kidney cells in an unbiased manner, our approach was useful in characterizing immune-cell deficiencies within DNA–protein kinase catalytic subunit (prkdc), interleukin-2 receptor γ a (il2rga), and double-homozygous–mutant fish, identifying blood cell losses in T, B, and natural killer cells within specific genetic mutants. Our analysis also uncovered novel cell types, including two classes of natural killer immune cells, classically defined and erythroid-primed hematopoietic stem and progenitor cells, mucin-secreting kidney cells, and kidney stem/progenitor cells. In total, our work provides the first, comprehensive, single-cell, transcriptomic analysis of kidney and marrow cells in the adult zebrafish