Doctor of Medicine, Washington University (2007)
Sézary syndrome (SS) is an aggressive cutaneous T-cell lymphoma (CTCL) of unknown etiology in which malignant cells circulate in the peripheral blood. To identify viral elements, gene fusions, and gene expression patterns associated with this lymphoma, flow cytometry was used to obtain matched pure populations of malignant Sézary cells (SCs) versus nonmalignant CD4(+) T cells from 3 patients for whole transcriptome, paired-end sequencing with an average depth of 112 million reads per sample. Pathway analysis of differentially expressed genes identified mis-regulation of PI3K/Akt, TGF?, and NF-?B pathways as well as T-cell receptor signaling. Bioinformatic analysis did not detect either nonhuman transcripts to support a viral etiology of SS or recurrently expressed gene fusions, but it did identify 21 SC-associated annotated long noncoding RNAs (lncRNAs). Transcriptome assembly by multiple algorithms identified 13 differentially expressed unannotated transcripts termed Sézary cell-associated transcripts (SeCATs) that include 12 predicted lncRNAs and a novel transcript with coding potential. High-throughput sequencing targeting the 3' end of polyadenylated transcripts in archived tumors from 24 additional patients with tumor-stage CTCL confirmed the differential expression of SC-associated lncRNAs and SeCATs in CTCL. Our findings characterize the SS transcriptome and support recent reports that implicate lncRNA dysregulation in human malignancies.
View details for DOI 10.1182/blood-2012-04-423061
View details for Web of Science ID 000311619200020
View details for PubMedID 22936659
Although complete remissions can be achieved in most patients younger than 60 years of age with untreated acute myeloid leukemia (AML), only 30-40 % of patients remain long-term survivors. Furthermore, long-term survivors represent only 10-15 % of all AML patients older than 60 years of age and <10 % of all patients with relapsed AML. The development of new treatments for AML is therefore needed. Novel therapies should target specific mechanisms and pathways implicated in the development and maintenance of AML, should strive to have better tolerability than conventional combination chemotherapy, be associated with improved quality of life and minimize utilization of health care resources. In this manuscript, we discuss the role of epigenetic regulators and immunomodulatory agents in the treatment of AML. Also, we review the data on inhibitors of protein homeostasis and its synergistic effect to DNA methyltransferase inhibitors, the potential role for inhibitors of heat shock proteins and the mitotic machinery and a novel formulation of conventional chemotherapeutic agents given at a fixed molar concentration. Finally, we briefly share our views on optimal clinical trial design and patient selection for future studies in AML.
View details for DOI 10.1007/s12185-012-1151-5
View details for Web of Science ID 000307764900006
View details for PubMedID 22907734
Rapid identification of non-human sequences (RINS) is an intersection-based pathogen detection workflow that utilizes a user-provided custom reference genome set for identification of non-human sequences in deep sequencing datasets. In <2 h, RINS correctly identified the known virus in the dataset SRR73726 and is compatible with any computer capable of running the prerequisite alignment and assembly programs. RINS accurately identifies sequencing reads from intact or mutated non-human genomes in a dataset and robustly generates contigs with these non-human sequences (Supplementary Material).RINS is available for free download at http://khavarilab.stanford.edu/resources.html.
View details for DOI 10.1093/bioinformatics/bts100
View details for Web of Science ID 000302806900022
View details for PubMedID 22377895
Numerous inositol polyphosphate 5-phosphatases catalyze the degradation of phosphatidylinositol-4,5-bisphosphate (PtdIns-4,5-P(2)) to phosphatidylinositol-4-phosphate (PtdIns-4-P). An alternative pathway to degrade PtdIns-4,5-P(2) is the hydrolysis of PtdIns-4,5-P(2) by a 4-phosphatase, leading to the production of PtdIns-5-P. Whereas the bacterial IpgD enzyme is known to catalyze this reaction, no such mammalian enzyme has been found. We have identified and characterized two previously undescribed human enzymes, PtdIns-4,5-P(2) 4-phosphatase type I and type II, which catalyze the hydrolysis of PtdIns-4,5-P(2) to phosphatidylinositol-5-phosphate (PtdIns-5-P). Both enzymes are ubiquitously expressed and localize to late endosomal/lysosomal membranes in epithelial cells. Overexpression of either enzyme in HeLa cells increases EGF-receptor degradation upon EGF stimulation.
View details for DOI 10.1073/pnas.0509740102
View details for Web of Science ID 000234350000016
View details for PubMedID 16365287
The subcellular localization of Ocrl, the inositol polyphosphate 5-phosphatase that is mutated in Lowe syndrome, was investigated by fluorescence microscopy. Ocrl was localized to endosomes and Golgi membranes along with clathrin, giantin, the mannose 6-phosphate receptor, transferrin, and the early endosomal antigen 1 endosomal marker in fixed cells. The endosomal localization of Ocrl was confirmed by live-cell time-lapse microscopy in which we monitored the dynamics of Ocrl on endosomes. GST binding assays show that Ocrl interacts with the clathrin terminal domain and the clathrin adaptor protein AP-2. Our findings suggest a role for Ocrl in endosomal receptor trafficking and sorting.
View details for DOI 10.1073/pnas.0405664101
View details for Web of Science ID 000223917900021
View details for PubMedID 15353600
Lowe syndrome is an X-linked disorder that has a complex phenotype that includes progressive renal failure and blindness. The disease is caused by mutations in an inositol polyphosphate 5-phosphatase designated OCRL. It has been shown that the OCRL protein is found on the surface of lysosomes and that a renal tubular cell line deficient in OCRL accumulated substrate phosphatidylinositol 4, 5-bisphosphate. Because this lipid is required for vesicle trafficking from lysosomes, we postulate that there is a defect in lysosomal enzyme trafficking in patients with Lowe syndrome that leads to increased extracellular lysosomal enzymes and might lead to tissue damage and contribute to the pathogenesis of the disease. We have measured seven lysosomal enzymes in the plasma of 15 patients with Lowe syndrome and 15 age-matched male controls. We find a 1.6- to 2.0-fold increase in all of the enzymes measured. When the data was analyzed by quintiles of activity for all of the enzymes, we found that 95% of values in the lowest quintile come from normal subjects whereas in the highest quintile 85% of the values are from patients with Lowe syndrome. The increased enzyme levels are not attributable to renal insufficiency because there was no difference in enzyme activity in the four patients with the highest creatinine levels compared with the six patients with the lowest creatinine values.
View details for Web of Science ID 000083649400067
View details for PubMedID 10557322