PubMed · 7877512
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A Schwartz, E Fernández-Repollet. 1994. Standardization for flow cytometry.. https://doi.org/10.1016/s0091-679x(08)61098-5
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In glioblastoma (GBM), the most frequent and lethal brain tumor, therapies suppressing recurrently altered signaling pathways failed to extend survival. However, in patient subsets, specific genetic lesions can confer sensitivity to targeted agents. By exploiting an integrated model based on patient-derived stem-like cells, faithfully recapitulating the original GBMs in vitro and in vivo, here, we identify a human GBM subset (∼9% of all GBMs) characterized by ERBB3 overexpression and nuclear accumulation. ERBB3 overexpression is driven by inheritable promoter methylation or post-transcriptional silencing of the oncosuppressor miR-205 and sustains the malignant phenotype. Overexpressed ERBB3 behaves as a specific signaling platform for fibroblast growth factor receptor (FGFR), driving PI3K/AKT/mTOR pathway hyperactivation, and overall metabolic upregulation. As a result, ERBB3 inhibition by specific antibodies is lethal for GBM stem-like cells and xenotransplants. These findings highlight a subset of patients eligible for ERBB3-targeted therapy.
A 58-year-old man experienced episodes of fever, vomiting, and diarrhea over a 2-year period. The laboratory evaluation during these attacks consistently disclosed thrombocytopenia, leukopenia, and elevated liver enzymes. A liver biopsy performed at one of these attacks showed a typical picture of granulomatous hepatitis. In retrospect, all episodes seemed to be associated with the ingestion of quinine. Indeed, such a correlation was established by a challenge with quinine. By using flow cytometry, quinine-dependent IgG antibodies to platelets were detected in the patient serum. By a two-color flow cytometric assay, the patient serum was also found to hold quinine-dependent antibodies specific for neutrophils, T lymphocytes, and B lymphocytes. Moreover, serum absorbed with neutrophils in the presence of quinine continued to react with platelets, T lymphocytes, and B lymphocytes; serum that was absorbed with mononuclear cells continued to react with neutrophils and platelets. These experiments indicated that the antigen targets were different on platelets, neutrophils, and lymphocytes. Further, the patient serum in the presence of quinine immunoprecipitated surface-labeled platelet proteins with electrophoretic mobilities closely resembling those of glycoprotein (GP) Ib/IX and GPIIb/IIIa. By a modified monoclonal antibody-specific immobilization of platelet antigens assay, the patient serum in the presence of quinine reacted with platelet GPIb/IX and GPIIb/IIIa. Also, the patient serum in the presence of quinine immunoprecipitated an uncharacterized 15-kD double-band from surface-labeled granulocyte proteins. We conclude that our patient's thrombocytopenia, neutropenia, and lymphocytopenia were caused by quinine-dependent antibodies and that these antibodies recognized cell lineage-specific epitopes.
A single base change in the helicase superfamily 1 domain of the yeast Saccharomyces cerevisiae SEN1 gene results in a heat-sensitive mutation that alters the cellular abundance of many RNA species. We compared the relative amounts of RNAs between cells that are wild-type and mutant after temperature-shift. In the mutant several RNAs were found to either decrease or increase in abundance. The affected RNAs include tRNAs, rRNAs and small nuclear and nucleolar RNAs. Many of the affected RNAs have been positively identified and include end-matured precursor tRNAs and the small nuclear and nucleolar RNAs U5 and snR40 and snR45. Several small nucleolar RNAs co-immunoprecipitate with Sen1 but differentially associate with the wild-type and mutant protein. Its inactivation also impairs precursor rRNA maturation, resulting in increased accumulation of 35S and 6S precursor rRNAs and reduced levels of 20S, 23S and 27S rRNA processing intermediates. Thus, Sen1 is required for the biosynthesis of various functionally distinct classes of nuclear RNAs. We propose that Sen1 is an RNA helicase acting on a wide range of RNA classes. Its effects on the targeted RNAs in turn enable ribonuclease activity.