Characterization of a cell line derived from rhabdoid tumor of kidney.

Rhabdoid tumor of kidney (RTK) is a rare, highly malignant childhood neoplasm of uncertain histogenesis. Several recent studies have described considerable histochemical heterogeneity among cases of RTK, with confusing combinations of epithelial, mesenchymal, myogenous, and neuroepithelial markers in some tumors. The present study characterizes the histology, ultrastructure, histochemistry, cytogenetics, and oncogene expression in a cell line derived from RTK. The surgical specimen, nude mouse xenograft, and cell cultures demonstrated characteristic intermediate filament whorls by electron microscopy and expressed vimentin (diffusely) and cytokeratin (focally, in hyaline cytoplasmic inclusions) without detectable desmin, Thy-1, or epithelial membrane antigen. S-100 protein was absent in the surgical specimen and heterotransplant, and was seen very weakly and focally in the cell cultures. Light microscopic features of cultures were unchanged by several compounds (tissue plasminogen activator, nerve growth factor, cyclic adenosine monophosphate) which induce differentiation of some other pediatric neoplasms. The growth factor requirements of RTK cultures indicate a cell with mesenchymal features. Insulin-like growth factor-2 mRNA was detected in the RTK and in three Wilms' tumors also studied. Unlike most Wilms' tumors, RTK expresses the c-myc rather than the N-myc oncogene.     

Herpes simplex virus-directed overreplication of chromosomal DNA physically linked to the simian virus 40 integration site of a transformed hamster cell line

In the simian virus 40 (SV40)-transformed hamster cell line Elona herpes simplex virus (HSV) induces amplification of SV40 DNA sequences to high-molecular-weight head-to-tail concatemers indicating an extrachromosomal rolling circle replication. In order to enable investigations concerning intrachromosomal amplification of SV40 DNA sequences and flanking cellular sequences a genomic library of Elona DNA was constructed in phage lambda. Clones harboring cellular DNA adjacent to the SV40 integration site were isolated. Plasmid subclones devoid of SV40 DNA sequences were used as hybridization probes against total DNA from HSV-infected cells. Thus the amplification of both flanking cellular sequences was demonstrated, indicating a bidirectional replication mode.     

Events preceding stable integration of SV40 genomes in a human cell line

We have examined the organization of integrated SV40 sequences in an uncloned population of a transformed human fibroblast cell line. Somatic cell hybrids between mouse B82 cells and human GM847 cells were examined for SV40 T-antigen expression and individual human chromosome presence. This analysis revealed that a functional SV40 genome is located on human chromosome 7. Restriction endonuclease digestion followed by blot hybridization of the parental human cell line revealed that it contains mutliple normal and defective SV40 copies integrated into the host genome in tandem. A similar analysis of several T-ag⁺ hybrid cell lines indicated that the integrated viral sequences in different hybrid cell lines (thus in different cells of the original population) are very closely related but not always identical. Analysis of subclones of GM847 also revealed such differences. Based upon these results, we postulate that following the initial integration event, viral as well as the flanking host DNA sequences become unstable and are subject to deletions and rearrangements. This short-lived structural instability is followed by highly stable integration of SV40 which is maintained in these cells or their hybrid derivatives for at least hundreds of cell generations.     

Characterization of functional mannose receptor in a continuous hybridoma cell line

ABSTRACT: BACKGROUND: The mannose receptor is the best described member of the type I transmembrane C-type lectins; however much remains unanswered about the biology of the receptor. One difficulty has been the inability to consistently express high levels of a functional full length mannose receptor cDNA in mammalian cells. Another difficulty has been the lack of a human macrophage cell line expressing a fully functional receptor. Commonly used human macrophage cell lines such as U937, THP-1, Mono-Mac and HL60 do not express the mannose receptor. We have developed a macrophage hybridoma cell line (43MR cells) created by fusion of U937 cells with primary human monocyte-derived macrophages, resulting in a non-adherent cell line expressing several properties of primary macrophages. The purpose of this study was to identify and select mannose receptor-expressing cells using fluorescence-activated cell sorting and to characterize the expression and function of the receptor. RESULTS: In the current study we show that the mannose receptor found on this novel cell has endocytic characteristics consistent with and similar to the mannose receptor found on the surface of monocyte-derived human macrophages and rat bone marrow-derived macrophages. In addition, we demonstrate that these cells engage and internalize pathogen particles such as S. aureus and C. albicans. We further establish the transfectability of these cells via the introduction of a plasmid expressing influenza A hemagglutinin. CONCLUSIONS: The 43MR cell line represents the first naturally expressed MR-positive cell line derived from a human macrophage background. This cell line provides an important cell model for other researchers for the study of human MR biology and host-pathogen interactions.     

Characterization of functional mannose receptor in a continuous hybridoma cell line

Background

The pathophysiological significance of variable region glycosylation of autoantibodies is still unclear. In the current study, the influence of the variable region N-linked oligosaccharides on the reactivity of three autoantibody specificities was investigated with Sambucus nigra agglutinin (SNA), which mainly binds to oligosaccharides with terminal ??2, 6-linked sialic acid on the variable region of IgG.

Methods

Twenty-seven patients with serum positive anti-neutrophil cytoplasmic autoantibodies (ANCA) against myeploperoxidase (MPO) or proteinase 3 (PR3), or autoantibodies against glomerular basement membrane (GBM) were included. Total IgG was isolated and separated into non-SNA-binding and SNA-binding fractions with SNA affinity chromatography. Antigen-specific IgG was purified by immunoaffinity chromatography.

Results

At the same concentration of IgG, the antigen binding level of non-SNA-binding IgG was significantly lower than that of SNA-binding IgG for MPO-ANCA (absorbance value at 405 nm, 0.572 ± 0.590 vs. 0.962 ± 0.670, P < 0.001) and for PR3-ANCA (0.362 ± 0.530 vs. 0.560 ± 0.531, P = 0.003). The antigen binding level of non-SNA-binding IgG was significantly higher than that of SNA-binding IgG for anti-GBM antibodies (1.301 ± 0.594 vs. 1.172 ± 0.583, P = 0.044). The level of variable region glycosylation of total IgG was significantly lower than that of affinity-purified MPO-ANCA (1.021 ± 0.201 vs. 1.434 ± 0.134, P = 0.004). The level of variable region glycosylation of total IgG was significantly higher than that of affinity-purified anti-GBM antibodies (1.034 ± 0.340 vs. 0.734 ± 0.333, P = 0.007). The SNA-binding fraction of MPO-ANCA-containing IgG and PR3-ANCA-containing IgG induced higher levels of neutrophil oxygen radical production than the corresponding non-SNA-binding fractions (P < 0.001 and P = 0.043, respectively). The level of variable region glycosylation of affinity-purified MPO-ANCA was higher in active AAV than the same patients in remission (P = 0.001).

Conclusion

Characteristics of variable region glycosylation of ANCA and anti-GBM antibodies were different from that of total IgG, which might influence the antigen-binding ability of these antibodies. Variable region glycosylation of ANCA might influence the effect of ANCA-induced neutrophils respiratory burst.     

High rate of multilocus deletion in a human tumor cell line

The nature of recessive mutations at the autosomal locus encodingthe purine salvage enzyme adenine phosphoribosyl transferase(APRT) was analyzed in a highly malignant human tumor cell line(the colorectal carcinoma line SW620). Mutant strains resistantto the purine analog 8-azaadenine were obtained in two steps.The first step selection for partial drug resistance producedstrains hemizygous for APRT as a result of high frequency lossof one allele. In the second step selection, low frequency basesubstitutions, small deletions, or insertions produced completeazaadenine resistance. Luria-Delbruck fluctuation analysis ofeach step of this process indicated that the rate of mutationresulting from allele loss was over 100-fold greater than therate of mutation resulting from base substitution. There wasno reproducible difference in the rate of loss of either ofthe two APRT alleles even though one maps to a rearranged chromosome.Similarly base substitution rates for the two alleles were notsignificantly different. Polymorphic loci surrounding APRT onchromosome 16 band q24 were lost together with the selectedgene in all isolates while polymorphic loci on the short armof the chromosome were retained. Thus the high frequency lossof APRT in SW620 appears to be the result of multilocus deletions.SW620 derivatives behaving as heterozygotes were also obtainedin the first step selections, but these constituted only 5%of isolates.     

Cytogenetic analysis of a cell line established from a Krukenberg tumor

Cytogenetic analysis was performed on a cell line, designated KS1, derived from a Krukenberg tumor. A modal chromosome number of 60-65 chromosomes was present, as were several clonal chromosome rearrangements involving, among others, chromosomes 2, 3, 6, 9, 11, 12, and 22. Ten to 30 double minutes were present in most cells.     

兔VX2肿瘤细胞系的建立及其生物学特性的观察

目的建立兔VX2肿瘤细胞系,观察其生物学特性。方法采用小块法对兔VX2肿瘤进行原代培养,体外传代观察,传代40次以上对培养细胞进行形态学观察、组织化学染色、细胞周期检查、核型分析、兔及裸鼠移植。结果新建立的兔VX2肿瘤细胞,呈多角形、短梭形,电镜下细胞内可见张力纤维、细胞间可见桥粒,细胞角蛋白阳性,体外连续培养10个月,传代70次以上,细胞倍增时间为34．5h,细胞周期测定G,期为69．3％,G：期为5．6％,S期为25．1％。染色体为亚三倍体核型,众数为58～62条。同种移植成瘤率100％,裸鼠移植成瘤率100％,无支原体污染。结论兔VX2肿瘤细胞系来源于兔鳞状细胞癌,可用于兔（较大动物）的肿瘤实验研究。     

阻断VEGFR-3表达对肿瘤细胞诱导的淋巴管内皮细胞增殖的影响

目的观察阻断VEGFR-3(F lt 4)表达对肿瘤细胞(前列腺癌细胞株PC3)诱导的淋巴管内皮细胞增殖的影响。方法实验分4组,第1组为对照组。每组有6孔,每孔具有相同细胞数2×105/m l,实验组每孔各加入试剂100 m l/L。第1组(对照组)加入淋巴管内皮细胞完全条件培养液(LEC)1 m l,第2组加入LEC 1 m l+兔血清100μl,第3组加入LEC 1 m l+PC3细胞上清100μl。第4组加入LEC+抗F lt 4抗体100μl。并于24、48、72、96 h观察各组淋巴管内皮细胞生长情况。各时间段计数第1~3组细胞数,第4组于72 h计数后,去除抗体,重新加入LEC+PC3细胞上清继续培养至120 h;除96 h外,其余各时间段均计数细胞数。比较各组细胞增殖情况。结果第1、2组淋巴管内皮细胞在加试剂后各时间段两组细胞数及形态无明显差别,第3组加入PC3细胞上清后,细胞数明显多于第1、2组。第4组加试剂后24、48、72 h细胞计数均少于前24 h。清除抗体后加入PC3细胞上清48 h计数细胞,细胞数仅略见增加。结论VEGF-C高表达的PC3细胞上清能显著刺激淋巴管内皮细胞增殖,阻断F lt4表达,可在一定程度上阻断PC3细胞上清促淋巴管内皮细胞增殖作用。     

Characterization of hormone-stimulated Na+ transport in a high-resistance clone of the MDCK cell line

The Madin-Darby canine kidney (MDCK) cell line forms an epithelial monolayer which expresses many of the morphological and functional properties of the renal collecting duct. The C7 subclone of the parent line forms an epithelium which expresses many of the characteristics of principal cells. The MDCK-C7 subclone forms a high-resistance epithelium that is capable of vectorial ion transport. We have found that this epithelium responds to aldosterone, antidiuretic hormone (ADH) and insulin like growth factor 1 (IGF1) with increases in amiloride-sensitive Na⁺ transport. The responses to aldosterone and ADH follow time-courses that are consistent with the action of these hormones in vivo. This is the first demonstration of IGF1-induced Na⁺ reabsorption in a mammalian model system. Interestingly, a maximal response to any one of these natriferic factors does not inhibit a subsequent response to another hormone. These studies indicate that the C7 subclone retains many of the natriferic responses of the native principal cells and is an ideal model for studying hormonal modulation of Na⁺ transport. Received: 12 January 1996/Accepted: 19 March 1996     

Characterization of the in vitro interaction between thymocytes and a medullary thymic epithelial cell line

T-cell differentiation is known to be mediated by lympho-stromal interactions. However, the precise role of cellular complexes formed during this process is far from clear. We have previously established a thymic medullary epithelial cell-line, E-5, and have shown the adherence of thymocytes by a receptor-mediated-mechanism. We report here that the thymocytes able of complex-formation with E-5 cells appear at day 16 of gestation. Moreover, while the proportion of such thymocytes is constant throughout post-natal life, their absolute number decreases with thymic involution. We have also investigated the influence of the genetic background of thymocytes on adherence and found that polymorphic regions of H-2 genes were not involved in contact recognition. Therefore, this type of lympho-stromal interactions is unlikely to participate in the education to self MHC-restriction. However, thymocytes from B6/lpr mice, which spontaneously develop systemic lupus erythematosus (SLE) and have impaired T-cell differentiation, were shown incapable of adhering to E-5 cells. These results are interpreted as showing that interaction between thymocytes and medullary epithelial cells reflect a discrete stage of T-cell differentiation.     

Analysis of dihydrofolate reductase gene amplification in a methotrexate-resistant human tumor cell line

Detailed cytogenetic and molecular biologic studies have been performed on the human KB tumor cell line and four methotrexate-resistant subclones. Results are presented, demonstrating that the gene encoding the target enzyme dihydrofolate reductase is increasingly amplified in progressively methotrexate-resistant subclones, and that dihydrofolate reductase sequences are localized to a homogeneously staining region on chromosome 10q.     

Characterization of the continuous green monkey spleen cell line 455

A continuous line of adult green monkey spleen cells has been established and designated 455 (according to the number of animal). Cell suspension for primary explantation has been prepared by perfusion and disaggregation of the organ. The obtained culture, which consisted of fibroblast-like cells with chromosome modal number 60, underwent 25 passages followed by ageing and death (line 455 D). At passage level 13 in 2 culture flasks with 455 D cells, islets of polygonal cells had developed within 35 days; they gave rise to a continuous cell line with chromosome modal number 110 (designated line 455). Line 455 has a high proliferative activity but low demands on the composition of culture media and it can be easily passaged with the bovine serum at concentration of 1-5%. It is highly sensitive to a number of viruses. It is not contaminated with bacteria, fungi, mycoplasmas or viruses, it does not have a tumourigenic activity. Hence, it is a promising cellular model for virological studies, in particular, for preparation of inactivated vaccines along with Vero and 4647 cells. The line 455 can be used for investigation of the problems of haemopoiesis and immunogenesis.     

Characterization of the complete RhPV 1 genomic sequence and an integration locus from a metastatic tumor.

The complete nucleotide sequence of the rhesus papillomavirus type 1 (RhPV 1) genome was determined. The genome is 8026 nucleotides in length and has a genomic organization similar to that of other characterized papillomaviruses. Sequence comparison of RhPV 1 to other papillomaviruses found similarities closest to HPV 16, a sexually transmitted human virus with a high oncogenic potential. Slight differences in the glucocorticoid responsive elements may explain disparate reliance upon added dexamethasone for transformation in vitro of these two papillomaviruses. In addition, a previously described DNA clone consisting of contiguous RhPV 1 and cellular sequences was partially sequenced. The disruption of the RhPV 1 genome due to integration occurred within the L1 open reading frame of RhPV 1, and no significant similarities were observed between the adjacent cellular sequences and information in various data banks.