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Results for “Cellular differentiation”

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PubMed2001

Effects of tissue transglutaminase on retinoic acid-induced cellular differentiation and protection against apoptosis.

Retinoic acid (RA) and its various synthetic analogs affect mammalian cell growth, differentiation, and apoptosis. Whereas treatment of the human leukemia cell line HL60 with RA results in cellular differentiation, addition of the synthetic retinoid, N-(4-hydroxyphenyl) retinamide (HPR), induces HL60 cells to undergo apoptosis. Moreover, pretreatment of HL60 cells as well as other cell lines (i.e. NIH3T3 cells) with RA blocks HPR-induced cell death. In attempting to discover the underlying biochemical activities that might account for these cellular effects, we found that monodansylcadaverine (MDC), which binds to the enzyme (transamidase) active site of tissue transglutaminase (TGase), eliminated RA protection against cell death and in fact caused RA to become an apoptotic factor, suggesting that the ability of RA to protect against apoptosis is linked to the expression of active TGase. Furthermore, it was determined that expression of exogenous TGase in cells exhibited enhanced GTP binding and transamidation activities and mimicked the survival advantage imparted by RA. We tested whether the ability of this dual function enzyme to limit HPR-mediated apoptosis was a result of the ability of TGase to bind GTP and/or catalyze transamidation and found that GTP binding was sufficient for the protective effect. Moreover, excessive transamidation activity did not appear to be detrimental to cell viability. These findings, taken together with observations that the TGase is frequently up-regulated by environmental stresses, suggest that TGase may function to ensure cell survival under conditions of differentiation and cell stress.

3T3 Cells↗

PubMed1975

Cellular differentiation of rat uterine adenocarcinoma cells by progesterone in vitro.

Transplantable cloned HTP/Cl culture was a stable line derived from a rat uterine adenocarcinoma that was induced by 7,12-dimethylbenz(a)anthracene in vivo and did not display density-dependent inhibition of growth. This HTP/Cl culture easily adapted to grow in a culture medium containing progesterone, 8 mug/ml. As compared with HTP/Cl culture, HTP/Cl/P8 culture grown in the presence of progesterone was contact inhibited, and a cellular differentiation was observed in the tumor tissues that developed after inoculation of cells. These actions of progesterone on uterine adenocarcinoma cells were completely reversible on removal of the hormone in vitro. These results appeared to indicate that progesterone was involved in the regulation of both cellular proliferation and differentiation. The possible mechanisms of the regulation of rat uterine adenocarcinoma cells by progesterone are discussed in relation to cellular levels of cyclic adenosine 3':5'-monophosphate in vitro.

Adenocarcinoma↗

PubMed2005

[Regulation of p21(WAF1/CiP1) expression during cellular differentiation].

In the present study, the molecular mechanisms regulating p 21(WAF1/CiP1) expression by basic helix-loop-helix (bHLH) factors during cellular differentiation were investigated. The cyclin dependent kinase inhibitor p 21 plays crucial roles during differentiation of osteoblasts and myoblasts. In the osteoblastic cell line MG 63, expression of the p 21 gene has been shown to be upregulated by E2A factors, members of the bHLH factor family. In addition, E2A-dependent activation of p21 promoter can be inhibited by another bHLH factor, TWIST. Using reporter assays with mutant p 21 promoters, a novel element was identified in the p21 promoter, which is essential for E2A-dependent activation and TWIST-mediated inhibition. Interestingly, in the myoblastic cell line C2C12, this sequence was not involved in E2A-dependent activation of p21 expression. Gel mobility shift assays showed a specific complex of the novel p21 promoter element with nuclear factor(s) of MG 63 cells. Complex formation was inhibited by the addition of anti-TWIST antibody. In contrast no complexes could be identified with C2C12 cells. These results raise the possibility that interactions of the bHLH factors with the novel p21 promoter element are cell type specific. This suggests a novel mechanism regulating p 21 expression.

Animals↗

PubMed1984

Effects of colchicine on milk yield, composition, and cellular differentiation during caprine lactogenesis.

Intramammary colchicine infusion into goats at parturition reduced milk yield by 20% during the 30 day experimental period. During the first week of lactation, milk composition from colchicine-treated udder halves had elevated somatic cell numbers, serum albumin concentration and pH, while citrate concentration was lower in comparison to uninfused glands. Levels of lactose from both infused and uninfused udder halves were normal during the first week of lactation. No differences were observed in degree of alveolar development in tissue samples collected prior to treatment. Light and electron microscopy suggested that colchicine-treated udder halves consisted predominantly of undifferentiated mammary secretory cells, while uninfused udder halves appeared more cytologically differentiated. Results demonstrated that intramammary colchicine infusion at parturition temporarily altered milk composition and inhibited mammary cellular differentiation.

Animals↗

PubMed1989

Inhibition of simian virus 40 T-antigen expression by cellular differentiation.

Murine 3T3T stem cells transfected with pSV3neo DNA were employed to study the effects of somatic cell differentiation on simian virus 40 (SV40) T-antigen expression. This experimental approach was used because the 3T3T cell line is a well-characterized in vitro adipocyte differentiation system and the pSV3neo plasmid contains the early region of the SV40 genome and a selective marker, G418 resistance. Cell clones containing stably integrated pSV3neo which expressed T antigen were isolated in G418-containing medium. Most of these cell clones differentiated poorly. However, several clones retained the ability to efficiently differentiate into adipocytes, and with these cell clones, it was established that adipocyte differentiation markedly repressed T-antigen expression. The differentiation-specific repression of T-antigen expression did not result from a loss of proliferative potential associated with terminal differentiation, because it was observed in adipocytes that could be restimulated to proliferate. In such cells, restimulation of cell growth induced reactivation of T-antigen expression. Repression of T-antigen expression was also demonstrated during differentiation of SV40 T-antigen-immortalized human keratinocytes. These results establish that the process of cellular differentiation can repress T-antigen expression in at least two distinct biological systems.

Adipose Tissue↗

PubMed1996

Cellular differentiation and development of pyloric mucosal metaplasia in the human gall-bladder.

The development of pyloric mucosal metaplasia (PMM) with regard to cellular differentiation in the human gallbladder was studied by mucin staining (paradoxical concanavalin A (Con A), galactose oxidase-Schiff (GOS) and alcian blue (pH 2.5) PAS (AB-PAS) and immunohistochemistry (pepsinogen II (PgII) and SH-9, and proliferating cell nuclear antigen (PCNA). PMM was divided into three stages of development by three-dimensional (3D) computer graphic reconstruction analysis. In the early stage, a transitional zone of PCNA positive cells was observed between areas of SH-9 and/or GOS reactive cells and class III and/or Pg II positive cells in flat monolayered epithelium. In the middle stage, shallow pits became apparent as areas enlarged, with these becoming deeper in the advanced stage, whereby SH-9 and/or GOS reactive cells and class III and/or Pg II positive cells were observed at the upper and lower portion of the pits, respectively, with PCNA-positive cells forming a narrow zone between the two cell populations. Consequently, the structure of PMM gradually resembles that of the normal gastric pyloric mucosa.

Cell Differentiation↗

PubMed1994

Correlation of cellular differentiation in human colorectal carcinoma and adenoma cell lines with metabolite profiles determined by 1H magnetic resonance spectroscopy.

The aim was to determine whether proton magnetic resonance spectroscopy (MRS) could grade human colorectal cells of differing malignant potential. A cell model of tumour development and progression comprising 2 non-tumorigenic adenoma lines and 4 carcinoma lines of increasing tumorigenicity was chosen. A gradual reduction in cellular differentiation and an accumulation of genetic alterations from adenoma to carcinoma characterized the selected cell lines. One-dimensional and 2-dimensional MRS showed that reduced differentiation in the cell model correlated with an increase in the levels of lipid, metabolites, the glycosylation intermediate uridine diphospho-N-acetylglucosamine and cell-surface fucosylation. Mutations involving the K-ras, APC and DCC genes are present both in adenoma- and in carcinoma-derived lines in this model, but the first evidence of an abnormality in the p53 gene was concomitant with the cells' ability to grow as a tumour in athymic nude mice. This genetic change coincided with the detection, by MRS, of UDP-hexose (ribose moiety, 2D MRS cross peak between H2 at 4.38 ppm and HI at 5.99 ppm) and the appearance of an additional fucosyl resonance (cross peak between-CH3 at 1.41 and H5 at 4.30 ppm) in the least tumorigenic of the carcinoma cell lines. An increase in complexity of the fucosylation spectral pattern was observed with further cellular de-differentiation and increased tumorigenicity. Collectively these data support the existence of an adenoma-carcinoma sequence.

Adenoma↗

PubMed1975

Adenylate and guanylate cyclase activities and cellular differentiation in rat small intestine.

Adenylate and guanylate cyclase activities were measured in rat small intestinal villus and crypt cells to determine possible correlations with cellular differentiation. Isolated intestinal cells were prepared by a method which effectively separates differentiated villus cells from undifferentiated crypt cells (J Biol Chem 248:2542, 1973). Crypt cells were found to have a significantly lower guanylate cyclase activity than villus cells. Adenylate cyclase activity was higher in crypt cells than villus cells, although the difference was less striking than the reverse gradient observed for guanylate cyclase. There was no gradient of activity for cyclic guanosine 3':5'-monophosphate phosphodiesterase. However, cyclic adenosine 3':5'-monophosphate phosphodiesterase activity was lower in villus cells. No villus to crypt gradient of cyclic adenosine 3':5'-monophosphate concentration was detected in mucosa frozen rapidly in liquid nitrogen. The properties and subcellular localization of the cyclases were also evaluated, and of particular interest was the localization of guanylate cyclase to the microvillus membrane and the confirmation of adenylate cyclase activity in the lateral-basal membrane. The villus to crypt gradient of guanylate cyclase suggests that this enzyme has a specialized role in the differentiated villus cell. The contrasting subcellular localization of the cyclases suggests that the cyclases may be interrelated, possibly reflecting the epithelial cell polarity for absorption and secretion.

Adenylyl Cyclases↗

PubMed2001

Differential cellular immunolocalization of renal tumour necrosis factor-alpha production during ischaemia versus endotoxaemia.

Both renal ischaemia and endotoxaemia provoke renal dysfunction and cellular injury. Although the clinical manifestation of each insult is similar (global renal dysfunction), ischaemia and endotoxaemia induce different patterns of cellular injury. Tumour necrosis factor-alpha (TNF-alpha) has been implicated in both types of renal injury; however, it remains unknown whether differential cellular TNF-alpha expression accounts for these changes. We hypothesized that renal glomerular cells and tubular cells differentially express TNF-alpha in response to ischaemia compared with endotoxaemia. To investigate this hypothesis, male Sprague-Dawley rats were anaesthetized and exposed to various time-periods of renal ischaemia, with or without reperfusion (sham operation=negative control), or lipopolysaccharide (LPS) 0.5 mg/kg intraperitoneally (i.p.). The kidneys were harvested following renal injury, and rat TNF-alpha protein expression was determined (by enzyme-linked immunosorbent assay), as were TNF-alpha bioactivity (by WEHI-164 cell clone cytotoxicity assay) and TNF-alpha cellular localization (by immunohistochemistry). TNF-alpha protein expression and TNF-alpha bioactivity peaked following 1 hr of ischaemia and 2 hr of reperfusion (48 +/- 11 pg/mg of protein, P < 0.05, and 12 +/- 0.5 x 10-3 units/mg of protein, P < 0.05, respectively). The concentration of TNF-alpha increased to a similar extent following exposure to LPS; however, while TNF-alpha production following ischaemia-reperfusion injury localized predominantly to renal tubular epithelial cells, animals exposed to LPS demonstrated a primarily glomerular distribution of TNF-alpha production. Hence, the cellular localization of renal TNF-alpha production appears to be injury specific, i.e. renal tubular cells are the primary source of TNF-alpha following an ischaemic insult, whereas LPS induces glomerular TNF-alpha production. The cellular source of TNF-alpha following different insults may have therapeutic implications for targeted inhibition of TNF-alpha production.

Animals↗

PubMed1998

Cellular differentiation in the maize leaf is disrupted by bundle sheath defective mutations.

The mature maize leaf is characterised by a series of parallel veins that are surrounded by concentric rings of bundle sheath (BS) and mesophyll (M) cells. To identify genes that control cellular differentiation patterns in the leaf, we have isolated a group of mutations that specifically disrupt the differentiation of a single cell type. In maize bundle sheath defective (bsd) mutants, C4 photosynthetic development is perturbed in BS cells while M cells appear to develop normally. Two mutants, bsd1 and bsd2, have been characterised in detail. Analysis of these mutants, and the corresponding Bsd1 and Bsd2 genes is providing an insight into cellular processes regulating photosynthetic cell type differentiation in maize.

Cell Differentiation↗

PubMed1989

Morphological change and cellular differentiation induced by cisplatin in human neuroblastoma cell lines.

In 1986 we reported on the capacity of cis-diaminedichloroplatinum(II) (cisplatin, CDDP) to induce erythroid cellular differentiation in the K562 cell. To continue our study of the differentiating activity of cisplatin, we treated two human neuroblastoma cell lines with different doses of the drug in vitro. Both cell lines showed changes in morphology; however, only one achieved a fully differentiated neuronal phenotype (cisplatin concentration 1 micrograms/ml). The differentiated neuroblastoma cells exhibited extensive neurite outgrowth that reached maximal elongation after 5 days of culture, forming several interconnections. Cisplatin could induce neuronal differentiation, as did retinoic acid, a neuroblastoma-differentiating agent. The results show that cisplatin should be a candidate for further in vitro and in vivo studies of induced differentiation.

Antigens, Neoplasm↗

PubMedDate not supplied

In vitro cytotoxicity and differential cellular sensitivity of derivatives of diamino acids. I. N1-methyl, N1-allyl, N1-(2-chloroethyl) and N1-propargyl ureas.

The in vitro cytotoxicity and differential cellular sensitivity of a series of new N1-methyl, N1-allyl, N1-2-chloroethyl and N1-propargyl urea derivatives of diamino acids were determined in the National Cancer Institute's primary antitumor drug screen. The compounds tested showed an in vitro anticancer activity similar to commercialized nitrosoureas such as CCNU, BCNU, MeCCNU, chlorozotocin, streptozotocin and PCNU. The alkylating moiety of the ureas seems to play a role in the general selectivity of our compounds. The N1-methyl and N1-2-chloroethyl urea derivatives are more selective for central nervous system cell lines and the N1-allyl urea derivatives are more selective for lung cancer cell lines. The N1-propargyl ureas did not show any particular selectivity in the 60 human cell lines tested.

Amino Acids, Diamino↗

PubMedDate not supplied

In vitro cytotoxicity and differential cellular sensitivity of derivatives of diamino acids. II. N1-methyl, N1-allyl, N1-(2-chloroethyl) and N1-propargyl nitrosoureas.

The in vitro cytotoxicity and differential cellular sensitivity of a series of new N1-methyl, N1-allyl, N1-2-chloroethyl and N1-propargyl nitrosourea derivatives of diamino acids were determined in the National Cancer Institute's primary antitumor drug screen. The compounds tested showed an in vitro anticancer activity similar to commercialized nitrosoureas such as CCNU, BCNU, MeCCNU, chlorozotocin, streptozotocin and PCNU. The alkylating moiety of the nitrosoureas seems to play a role in the general selectivity of our compounds. The N1-methyl and N1-2-chloroethyl nitrosourea derivatives are more selective for central nervous system cell lines, the N1-allyl nitrosourea derivatives are more selective for lung cancer cell lines and the N1-propargyl nitrosoureas are more selective for leukemia cell lines.

Amino Acids, Diamino↗

PubMed2003

Quantification of expression levels of cellular differentiation markers does not support a general shift in the cellular phenotype of osteoarthritic chondrocytes.

Many studies have shown increased anabolic activity in osteoarthritic cartilage and have suggested changes in the cellular phenotypes of articular chondrocytes. Most of these studies relied on non-quantitative technologies, which did not allow the estimation of the relative importance of the different differentiation phenomena. In the present study, we developed and used quantitative PCR assays for collagen types I, II(total), IIA, III, and X as marker genes indicating cellular synthetic activity (collagen type II) as well as differentiation pattern of chondrocytes (collagen types I, IIA, III, and X) and quantified these genes in normal, early degenerative, and late stage osteoarthritic cartilage in parallel. At first sight, our results confirmed previously published data showing hardly any expression of collagen genes in normal and significantly enhanced expression in osteoarthritic cartilage. This included collagen types II, III, and IIA, but also collagen types I(alpha1) and X. However, if one considers the ratios of the various markers of chondrocytic differentiation in comparison to collagen type II, the main synthetic product of differentiated chondrocytes, no shift in the cellular phenotype was detectable. In fact, expression ratios remained constant or were even decreased in osteoarthritic cartilage. Our results confirm that normal adult human articular chondrocytes display hardly any expression activity of the collagen types investigated, whereas osteoarthritic chondrocytes show very increased synthetic activity. The largely unchanged ratios of collagen subtypes investigated indicate that no general shift in the cellular phenotype does occur in osteoarthritic cartilage as suggested by previous investigations.

Adult↗

PubMed1994

A-factor as a microbial hormone that controls cellular differentiation and secondary metabolism in Streptomyces griseus.

A-factor, containing a gamma-butyrolactone in its structure, is an autoregulatory factor or a 'microbial hormone' controlling secondary metabolism and cellular differentiation in Streptomyces griseus. A-factor exerts its regulatory role by binding to a specific receptor protein which, in the absence of A-factor, acts as a repressor-type regulator for morphological and physiological differentiation. In the signal relay leading to streptomycin production in S. griseus, the A-factor signal is transferred from the A-factor receptor to the upstream activation sequence of a regulatory gene, strR, in the streptomycin biosynthetic gene cluster via an A-factor-dependent protein that serves as a transcription factor for strR. The StrR protein thus induced appears to activate the transcription of other streptomycin-production genes. The presence of A-factor homologues in a wide variety of Streptomyces species and distantly related bacteria implies the generality of gamma-butyrolactones as chemical cellular signalling molecules in microorganisms.

4-Butyrolactone↗

PubMed1986

Cellular differentiation and prognosis in embryonal rhabdomyosarcoma. A report from the Cooperative Soft Tissue Sarcoma Study 1981 (CWS 81).

Sixty-four cases of embryonal rhabdomyosarcoma (eRMS) were investigated for cellular differentiation by light microscopy. Of these 64 cases 20 were studied by means of immunohistochemistry. Histologically, three subgroups could be distinguished: primitive (less than 10% rhabdomyoblasts), intermediate (10-50% rhabdomyoblasts) and well differentiated (greater than 50% rhabdomyoblasts) eRMS. Vimentin-positive cells predominated in the primitive eRMS. Intermediate eRMS showed large proportions of desmin-positive cells but vimentin containing cells were also numerous. Myoglobin could only be demonstrated in well differentiated eRMS. Primitive and well differentiated eRMS mainly occurred in the head and neck area, whereas intermediate eRMS were predominantly located in the abdomen. Stage III and IV tumours predominated in cases of primitive eRMS, whereas lower stages were noted in cases of intermediate and well differentiated eRMS. Response to chemotherapy, evaluated after seven weeks of treatment, was achieved in 10/15 (66%) cases of primitive, in 16/19 (84%) cases of intermediate and 5/5 cases of well differentiated eRMS. It is concluded from the current study that the three subgroups of eRMS differ not only by cytological differentiation but also by site of predilection, stage at time of diagnosis and response to chemotherapy.

Abdominal Neoplasms↗

PubMed1994

Expression of manganese superoxide dismutase promotes cellular differentiation.

Manganese superoxide dismutase (MnSOD) is a nuclear encoded mitochondrial matrix enzyme that scavenges toxic superoxide radicals. It has been shown that increased generation of reactive oxygen species is associated with the differentiation of microorganisms. To test the hypothesis that the ability of mitochondrial superoxide dismutase to neutralize a cellular hyperoxidant state is important for differentiation of mammalian cells, we examined the effect of transfection of MnSOD into mouse embryo fibroblasts on cellular differentiation. C3H10T1/2 cells served as a model for differentiation because these cells can be triggered to differentiate into myoblasts, adipocytes, and chondrocytes by treatment with 5-azacytidine. In this report, myoblast differentiation was defined by the presence of multinucleated cells, appearance of Z-bands, and expression of actin and desmin in the differentiated cells. Transfection of MnSOD gene was found to greatly enhance differentiation of C3H10T1/2 cells into myoblasts by 5-azacytidine. This result identifies MnSOD as an important factor for cell differentiation and supports a role for reactive oxygen species in the process of cellular differentiation.

Animals↗

PubMed1988

Expression of the CD 15 antigen is a marker of cellular differentiation in cervical intra-epithelial neoplasia (CIN).

The CD 15 antigen (3-fucosyl N-acetyllactosamine), present on the outer cell membrane of cervical squamous epithelial cells, is recognized by the monoclonal antibody MC2, which is similar to several commercially available antibodies. Staining sections of cervical biopsies with MC2 clearly demonstrates the zone of supra-basal differentiated cells in the normal squamous epithelium. Staining with MC2 also demonstrates the diminished proportion of this zone occurring with grades of CIN, reflecting progressive de-differentiation of the epithelium. In immature squamous metaplastic epithelium, absence of cytoplasmic differentiation is reflected by lack of staining. As expression of the CD 15 antigen by cervical squamous cells mirrors cytoplasmic maturity and is a marker of cellular differentiation, staining colposcopic biopsies with MC2 may aid the routine histopathological grading of CIN. A comparison is made between the staining pattern observed using MC2 with that of two commercially available antibodies (Leu M1 and Dako M1), and a possible role for the CD 15 antigen in cellular adhesion in squamous mucosae is discussed.

Antibodies, Monoclonal↗