A study on the antigenicity of a human cell line propagated in a heterologous medium

Résumé Des cellules HeLa cultivées dans un milieu qui contient du sérum de cheval, ont été transférées dans un milieu contenant du sérum humain. On a essayé, à différents moments, de détecter la présence de protéines de cheval dans les cellules transférées. Seules les cellules, qui ont été retirées du milieu hétérologue avant 48 h, donnent des réactions sérologiques positives.     

The human leukemia cell line, THP-1: a multifacetted model for the study of monocyte-macrophage differentiation

THP-1 is a human monocytic leukemia cell line. After treatment with phorbol esters, THP-1 cells differentiate into macrophage-like cells which mimic native monocyte-derived macrophages in several respects. Compared to other human myeloid cell lines, such as HL-60, U937, KG-1, or HEL cell lines, differentiated THP-1 cells behave more like native monocyte-derived macrophages. Because of these characteristics, the THP-1 cell line provides a valuable model for studying the mechanisms involved in macrophage differentiation, and for exploring the regulation of macrophage-specific genes as they relate to physiological functions displayed by these cells.     

Transplantable line of amelanotic hamster melanoma resulting from abrupt depigmentation

Zusammenfassung Im Anschluss an die plötzliche Depigmentation eines stark pigmentierten Transplantationsmelanoms des Goldhamsters wurde ein neuer pigmentloser Tumorzellstamm erhalten. Er befindet sich in seiner 39. Transplantationsgeneration. Der Tumor dieses Stammes läuft bei allen Tieren nach einer Latenzperiode von 4–5 Tagen an und führt auf Ende des ersten Monats zum Exitus. Die mikroskopische Struktur ist durch alveoläre und diffuse Anordnung von ovalen und runden, pigmentlosen Zellen und viele Mitosen charakterisiert. Zytochemisch zeigen die Tumorzellen negative DOPA-Oxydase und Tyrosinase-Reaktionen.     

Induction, by 5-bromo-2'-deoxyuridine, of a "foamy" virus previously undetected in hamster cells transformed by SV40]

TSV5 clone 2 cells in normal conditions of culture contain only an expressed RNA virus (R-type virus). However, exposure of the cells to 5-bromo-2'-deoxyuridine with dexamethasone, induced synthesis of a syncitium-forming ("Foamy") virus. In other hamster cell lines, the same treatment fails to induce a "foamy" virus. The origin of this "foamy" virus is discussed.     

Tyrosine hydroxylase activity in a transplantable islet cell tumour of golden hamster

Zusammenfassung In einem transplantierbaren Insel-zelltumor des Goldhamsters ist eine Tyrosinhydroxylase-Aktivität gefunden. Die hohe Aktivität der Enzyme zusammen mit einer starken Konzentration von Tyrosin deutet auf eine schnelle Synthese von Dopa in den Tumorzellen. Die Anwesenheit der Dopametaboliten DOPAC und HVA im Tumor wurde gezeigt.

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This work was supported by grants from the Swedish Cancer Society (No. 67-111) and was carried out within a research organization sponsored by the Swedish Medical Research Council (Projects No. B70-14X-712-05 and No. B70-14X-56-06).     

The human leukemia cell line,THP-1: A multifacetted model for the study of monocyte-macrophage differentiation

Summary THP-1 is a human monocytic leukemia cell line. After treatment with phorbol esters, THP-1 cells differentiate into macrophage-like cells which mimic native monocyte-derived macrophages in several respects. Compared to other human myeloid cell lines, such as HL-60, U937, KG-1, or HEL cell lines, differentiated THP-1 cells behave more like native monocyte-derived macrophages. Because of these characteristics, the THP-1 cell line provides a valuable model for studying the mechanisms involved in macrophage differentiation, and for exploring the regulation of macrophage-specific genes as they relate to physiological functions displayed by these cells.     

Identification of cancer stem cell-like cells from human epithelial ovarian carcinoma cell line

Cancer stem cells (CSCs) play an important role in the development, invasion, and drug resistance of carcinoma, but the exact phenotype and characteristics of ovarian CSCs are still disputable. In this study, we identified cancer stem cell-like cells (CSC-LCs) and investigated their characteristics from the ovarian adenocarcinoma cell line 3AO. Our results showed that CSC-LCs were enriched in sphere-forming test and highly expressed CD44⁺CD24⁻. The spheres and CD24⁻ cells possessed strong tumorigenic ability by transplantation into nonobese diabetic/severe combined immunodeficient mice. CD44⁺CD24⁻ cells expressed stem cell markers and differentiated to CD44⁺CD24⁺ cells by immunofluorescence assay and fluorescence-activated cell-sorting analysis. In vitro experiments verified that CD44⁺CD24⁻ cells were markedly resistant to carboplatin and paclitaxol. In conclusion, our study identifies the CD44⁺CD24⁻ phenotype, self-renewal, high tumorigenicity, differentiation potential, and drug resistance of ovarian CSC-LCs. Our findings may provide the evidence needed to explore a new strategy in the treatment of ovarian cancer.     

K252a: A new blocker of the cell-cycle at G1 phase in a human hepatoma cell line

The administration of 200 nM K252a to HuH7 suppressed the proliferation of the cells almost completely. The uptake of [³H]thymidine was inhibited, and flow cytometry revealed only one peak at 2C on day 3 after treatment with 100 nM K252a. The expression of proto-oncogene c-myc was not reduced. Despite the blockage at G1, both the size of the cells and the amount of cell protein had increased by 4 times by day 3 after treatment with K252a, while the cells secreted albumin and -fetoprotein into the medium as usual. These results show that K252a can increase the cell size of HuH7 without losing its function by blocking the cell cycle at G1 phase.     

Enhanced expression of Epstein-Barr virus early antigens by antitubulin agents in a latently infected human lymphoblastoid cell line

28 anticancer agents have been surveyed for Epstein-Barr virus (EBV) activating potency. Two vinca alkaloids with antitubulin activity, vinblastine (VLB) and vincristine (VCR), enhanced the expression of EBV early antigens (EA) in a latently infected human lymphoblastoid cell line (Raji), when used in combination with n-butyrate. Other antitubulin agents, colchicine, colcemid, and podophyllotoxin, had the same effect, although their effects were less than that of the potent tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA).     

Effect of human interferon on viral production in a cell line chronically infected by a type D retrovirus (Mason-Pfizer virus)]

Human interferon specifically inhibits the viral multiplication in a human cell line infected by a type D retrovirus, the Mason-Pfizer virus (MPV). This inhibition is less important than for type C viruses.     

Characterization of a thermosensitive protein from human milk whey

Summary A human milk whey protein, which aggregates at room temperature and resolubilizes when cooled, was purified by chromatography on hydroxyapatite. The present study demonstrated that the thermosensitive protein is a nonphosphorylated form of -casein.We thank Dr J.J. Pahud for preparation of anti Na-caseinate antiserum and Miss D. Fumeaux for technical assistance.     

Dopa-decarboxylase and monoamine oxidase activities in a transplantable islet cell tumour of the golden hamster

Zusammenfassung In einem transplantierbaren Inselzelltumor des Goldhamsters, der neben 5-Hydroxytryptamin, Dopa und Dopamin eine bisher unidentifizierte, vermutlich monoaminähnliche Substanz enthält, wurde eine hohe Dopadecarboxylase- und Monoaminooxydaseaktivität gefunden. Nach Dopa-decarboxylasehemmung wurde eine starke Anhäufung von Dopa im Tumorgewebe beobachtet; dieser Befund weist auf eine schnelle Monoaminsynthese und einen schnellen Monoaminumsatz im Tumorgewebe hin.

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This work was supported by grants from the Swedish Cancer Society (67–111) and was carried out within a research organization sponsored by the Swedish Medical Research Council (Projects No. B69-14X-56-05C and B69-14X-712-04C).