Search results for "CELL DIVISION"
showing 10 items of 457 documents
Overexpression of bone morphogenetic protein-6 (BMP-6) in murine epidermis suppresses skin tumor formation by induction of apoptosis and downregulati…
2001
Bone morphogenetic protein-6 (BMP-6) is a member of the transforming growth factor-beta superfamily. In murine skin, BMP-6 is highly expressed in postmitotic keratinocytes from day 15.5 p.c. till day 6 p.p. Expression in adult skin remains at very low levels, but pathological conditions such as wounding induce the expression of BMP-6. We demonstrate that tumor promotion by TPA (12-O-tetradecanoylphorbol-13-acetate) also induces expression of BMP-6 in suprabasal keratinocytes. This induction is due to post-transcriptional regulation since the level of BMP-6 mRNA remained unchanged. We performed two-stage skin carcinogenesis experiments with transgenic mice epidermally overexpressing BMP-6. T…
Chemical skin carcinogenesis is prevented in mice by the induced expression of a TGF-β related transgene
1995
Skin papillomas and squamous cell carcinomas (SCCs) are induced in mice by tumor initiation with a carcinogen followed by tumor promotion with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). These usually arise from preneoplastic lesions characterized by epidermal proliferation and hyperplasia, dermal edema, and inflammation. To evaluate the role of polypeptide growth factors in chemically induced skin carcinogenesis, we used transgenic mice carrying the cDNA for a TGF-β related molecule, bone morphogenetic protein-4 (BMP-4), under the control of the regulatory elements of the cytokeratin IV* gene in a skin carcinogenesis protocol. Control non-transgenic littermates and BMP-4 …
Tubulin gene expression persists during all changes in microtubular arrays related to cell shaping in growing barley leaves
1998
Summary Levels of α-tubulin RNA were determined in consecutive leaf segments taken along young, growing barley leaves by Northern blotting. The leaves exhibited a developmental gradient typical of graminaceous species ranging from a meristem at the base to fully differentiated cells at the tip. The objective was to ascertain whether or not high steady-state tubulin RNA levels accompany characteristic changes in microtubular arrays known to occur during cell division and differentiation. Of particular interest was the differentiation zone comprising a succession of well defined changes in microtubular arrays that appear to be involved in the control of cell shaping. High steady-state levels …
Hypoxia and anemia: effects on tumor biology and treatment resistance
2004
In locally advanced solid tumors, oxygen (O2) delivery is frequently reduced or even abolished. This is due to abnormalities of the tumor microvasculature, adverse diffusion geometries, and tumor-associated and/or therapy-induced anemia. Up to 50-60% of locally advanced solid tumors may exhibit hypoxic and/or anoxic tissue areas that are heterogeneously distributed within the tumor mass. In approximately 30% of pretreatment patients, a decreased O2 transport capacity of the blood as a result of tumor-associated anemia can greatly contribute to the development of tumor hypoxia. While normal tissues can compensate for this O2 deficiency status by a rise in blood flow rate, locally advanced tu…
Combination of the novel farnesyltransferase inhibitor RPR130401 and the geranylgeranyltransferase-1 inhibitor GGTI-298 disrupts MAP kinase activatio…
1999
To test the Kirsten-Ras (Ki-Ras) alternative prenylation hypothesis in malignant transformation, we used a novel farnesyltransferase inhibitor competitive to farnesyl-pyrophosphate, RPR130401, and a CaaX peptidomimetic geranylgeranyltransferase-1 inhibitor GGTI-298. In Ki-Ras-overexpressing transformed adrenocortical cells, RPR130401 at 1-10 microM inhibited very efficiently the [(3)H]farnesyl but not [(3)H]geranylgeranyl transfer to Ras. However, proliferation of these cells was only slightly sensitive to RPR130401 (IC(50)=30 microM). GGTI-298 inhibited the growth of these cells with an IC(50) of 11 microM but cell lysis was observed at 15 microM. The combination of 10 microM RPR130401 and…
Lysine synthesis control in Corynebacterium glutamicum RC 115 in mixed substrate (glucose-acetate) medium.
2003
The effect of acetate as a glucose co-substrate on growth, lysine synthesis and experimental lysine yield from carbon substrates by Corynebacterium glutamicum RC 115 was investigated. It was found that low amounts of acetate, injected with a glucose-acetate pulse into the steady-state continuous culture in bioreactor, caused a slight decrease in the specific rates of glucose uptake and bacterial growth, but a significant increase in the cell specific rate of lysine synthesis and an increase in lysine yield. In contrast, acetate injected in high amounts was followed by a drastic decrease in the values of these parameters. A strong increase in experimental lysine yield under the latter condit…
Isolation and characterization of a 60-70-kD plasma membrane glycoprotein involved in the contact-dependent inhibition of growth
1990
Previous studies have shown that plasma membrane compounds are involved in the contact-dependent inhibition of growth of human diploid fibroblasts. The purification of the active plasma membrane glycoprotein is described in this report. The glycoprotein has an apparent molecular mass of 60-70 kD and, due to differential sialylation, isoelectric points between pH 5.5. and 6.2. Treatment with sialidase yielded one spot in two-dimensional gel electrophoresis with an isoelectric point of 6.3. After removal of the N-glycosidically linked oligosaccharide chains, the apparent molecular mass is reduced by approximately 22 kD. Treatment was diluted NaOH, which removes the O-glycosidically linked por…
Contact-dependent inhibition of growth of normal diploid human fibroblasts by plasma membrane glycoproteins.
1988
Homeostasis in vivo is maintained by a highly complex network of positive and negative signals. At the cellular level, this regulatory microenvironment can be divided, in a simplified fashion, into two major compartments: the humoral compartment, including compounds such as hormones, growth factors and nutrients, and the contact-environment compartment, including cell-cell and cell-matrix interactions. At least in cultures of diploid, non-transformed cells, cell-cell and cell-matrix interactions have been shown to be of major importance for the regulation of growth as well as of differentiation. Although until now the glycoprotein involved in the contact-dependent inhibition of growth has n…
GM-CSF restores innate, but not adaptive, immune responses in glucocorticoid-immunosuppressed human blood in vitro.
2003
Abstract Infection remains the major complication of immunosuppressive therapy in organ transplantation. Therefore, reconstitution of the innate immunity against infections, without activation of the adaptive immune responses, to prevent graft rejection is a clinically desirable status in transplant recipients. We found that GM-CSF restored TNF mRNA and protein expression without inducing IL-2 production and T cell proliferation in glucocorticoid-immunosuppressed blood from either healthy donors or liver transplant patients. Gene array experiments indicated that GM-CSF selectively restored a variety of dexamethasone-suppressed, LPS-inducible genes relevant for innate immunity. A possible ex…
Fanconi's anaemia cells have normal steady-state levels and repair of oxidative DNA base modifications sensitive to Fpg protein
1998
Abstract Cells from Fanconi's anaemia (FA) patients are abnormally sensitive to oxygen. However, a distinct genetic defect in either the cellular defence against reactive oxygen species (ROS) or in their metabolic generation has not been identified to date. Recently, the gene for the human 8-hydroxyguanine (8-oxoG) glycosylase, which removes this oxidative base modification from the genome, has been localized on chromosome 3p25, i.e., in the same region as the FA complementation group D (FAD) gene. We therefore studied the removal of photosensitization-induced 8-oxoG residues from the DNA of FA cells, using Fpg protein, the bacterial 8-oxoG glycosylase, to quantify the lesions by alkaline e…