Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thirty epithelial cell strains were isolated from human carcinomas and normal epithelial tissues by collagenase digestion and selective removal of fibroblasts with trypsin-Versene. Most strains were obtained from metastatic carcinomas or epithelia of the urinary and intestinal tracts. The success rate for growth of both neoplastic and normal tissues (excluding skin) was 38%. Six of these strains showed gross morphologic and chromosome changes typical of malignant cells. Nine resembled normal epithelium. The other 15 exhibited some degree of morphologic change from normal.
 ...
PMID:Epithelial cell cultures from normal and cancerous human tissues. 17 12

Two sublines of a breast epithelial cell culture, MCF-10, derived from human fibrocystic mammary tissue exhibit immortality after extended cultivation in low calcium concentrations (0.03-0.06 mM) and floating transfers in low calcium (MCF-10F), or by trypsin-Versene passages in the customary (normal) calcium levels, 1.05 mM (MCF-10A). Both sublines have been maintained as separate entities after 2.3 years (849 days) in vitro and at present have been in culture for longer than 4 years. MCF-10 has the characteristics of normal breast epithelium by the following criteria: (a) lack of tumorigenicity in nude mice; (b) three-dimensional growth in collagen; (c) growth in culture that is controlled by hormones and growth factors; (d) lack of anchorage-independent growth; and (e) dome formation in confluent cultures. Cytogenetic analysis prior to immortalization showed normal diploid cells; although later passages showed minimal rearrangement and near-diploidy, the immortal cells were not karyotypically normal. The emergence of an immortal culture in normal calcium media was not an inherent characteristic of the original tissue from which MCF-10 was derived since reactivated cryo-preserved cells from cultures grown for 0.3 and 1.2 years in low calcium were incapable of sustained growth in normal calcium.
 ...
PMID:Isolation and characterization of a spontaneously immortalized human breast epithelial cell line, MCF-10. 197 13

The syncytial trophoblast of the human placenta forms by the fusion of mononuclear cytotrophoblast cells. Cytotrophoblast cells only fuse with other trophoblastic cells, indicating a specificity to this interaction. To explore the cellular aggregation which precedes fusion, we examined the association of cytotrophoblast cells isolated from term placentae and JEG-3 choriocarcinoma cells, a cytotrophoblast-like cell line, in suspension culture. Cytotrophoblast cells were isolated by dispersion of chorionic villi in trypsin-DNase in Ca2+/Mg2(+)-free medium. JEG-3 cells were released from culture flasks by trypsinization in Versene-EDTA buffer. In suspension culture, each cell type aggregated forming tissue-like masses over a 24-hr period. Transmission electron microscope analysis demonstrated the formation of numerous desmosomes between the aggregated cells. In outgrowth culture, the aggregates created in suspension were maintained as microvilli-covered multicellular structures with hollow cores. The extent of aggregation was dependent upon the concentration of cells in the incubations with greater aggregation occurring with higher cell densities. Aggregation of both cytotrophoblast cells and JEG-3 cells progressed rapidly during the initial 10 hr of incubation and then continued at a slower rate. Aggregation took place in serum-containing and serum-free medium, but was impeded in Ca2+/Mg2(+)-free medium. Incubation of JEG-3 and cytotrophoblast cells in the presence of the protein synthesis inhibitor, cycloheximide, prevented aggregation, whereas the inhibitor of N-linked glycosylation, tunicamycin, did not. The inhibitor of RNA synthesis, actinomycin D, had no effect on the aggregation of the cells during the initial 6 hr of aggregation. These findings suggest that trypsin treatment in Ca2+/Mg2(+)-poor medium removed a protein(s) from the trophoblast cell surface which must be resynthesized for cell-cell association to take place.
 ...
PMID:Aggregation of dispersed human cytotrophoblastic cells: lessons relevant to the morphogenesis of the placenta. 229 58

Methods are described to study cell surface and cytoplasmic antigens of cultured human glioma, fetal brain cells and fibroblasts using flow cytometry. This required harvesting the cultured cells with Versene or mild trypsin treatment and fixation in 4% paraformaldehyde prior to staining for glial fibrillary acidic protein (GFAP) and fibronectin using indirect immunofluorescence. At passage 10, 38% of fetal brain cells [CHII] were GFAP-positive but at passage 14 only 3.5% expressed GFAP. Two glioblastomas and an anaplastic astrocytoma had 38.8%, 6.7% and 81.3% GFAP-positive cells, respectively. Of the 10(4) cells studied, 91.6%, 79.1% and 40.8% were fibronectin-positive for glioblastoma multiforme [12-18], oligodendroglioma [12-10] and fetal brain [CHII] cells, respectively. Two fibroblast lines had 33.5% and 43.1% of the cells expressing fibronectin. The validity of these results was confirmed by staining for GFAP and fibronectin using peroxidase-antiperoxidase and immunofluorescence microscopy. Using low angle forward light scatter to estimate cell size and gating techniques it was found that GFAP-positive CHII and anaplastic astrocytoma cells were generally larger than GFAP-negative cells of the same type. No correlation between cell size and fibronectin expression was found for glioblastoma [12-18] cells. These results demonstrate the validity of the described methods and illustrate some specific applications and the potential value of flow cytometry to neurooncology.
 ...
PMID:Application of flow cytometry to analyses of cultured human glioma and fetal brain cells. 388 48

Many human tumours are hyperdiploid, particularly in advanced stages of growth. The purpose of the present work was to investigate whether exposure to hypoxia followed by reoxygenation might induce hyperploidisation of diploid human tumour cells in vitro. The investigation was performed by using the diploid melanoma cell line BEX-c (median chromosome number, 46; DNA index, 1.10 +/- 0.04) as test line and the hyperdiploid melanoma cell line SAX-c (median chromosome number, 61; DNA index, 1.42 +/- 0.03) as control line. Cell cultures kept in glass dishes in air-tight steel chambers were exposed to hypoxia (O2 concentrations < 10 p.p.m. or < 100 p.p.m.) at 37 degrees C for 24 h. DNA content was measured by flow cytometry. Metaphase spreads banded with trypsin-Versene-Giemsa were examined to determine the number of chromosomes per cell. An electronic particle counter was used to measure cell volume. The expression of p53 and pRb was studied by Western blot analysis. Transient exposure to hypoxia was found to induce a doubling of the number of chromosomes in BEX-c but not in SAX-c. The fraction of the BEX-c metaphase spreads with 92 chromosomes was approximately 10% at 18 h after reoxygenation, decreased to approximately 2% at 7 days after reoxygenation and then increased gradually with time. The whole cell population became tetraploid within 25 weeks. BEX-c and SAX-c behaved differently during the 24 h hypoxia exposure. Cell volume and fraction of cells in G2 + M increased with time in BEX-c but remained essentially unchanged in SAX-c. On the other hand, the expression of p53 and pRb was similar for the two lines; hypoxia induced increased expression of p53 and hypophosphorylation of pRb.
 ...
PMID:Hypoxia-induced tetraploidisation of a diploid human melanoma cell line in vitro. 876 66