Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently we demonstrated in a transgenic mouse model that hepatocyte growth factor (HGF) inhibits c-myc dependent hepatocarcinogenesis. The inhibitory effects of HGF in carcinogenesis were further characterized using a series of rat liver epithelial (RLE) cell lines which were transformed in vitro with either aflatoxin or oncogenes, or spontaneously. HGF caused a cytostatic effect and enhanced cell motility in spontaneously and aflatoxin-transformed cells. In normal RLE cells HGF was slightly stimulatory and did not induce scattering. The HGF receptor was tyrosine phosphorylated in all cell lines, indicating that it is functionally active and capable of signaling events. In the aflatoxin transformed cells HGF also induced apoptosis, associated with constitutive c-myc expression and 1 Kb bax-alpha transcripts. These findings indicate that transformed RLE cell lines may provide a useful model to further examine the mechanism(s) by which HGF and its receptor modulate neoplastic development.
 ...
PMID:Growth inhibition and induction of apoptosis by HGF in transformed rat liver epithelial cells. 924 Apr 48

Two different protein tyrosine kinases were detected in the cytosolic fraction of different human tumor tissues. After partial purification, the two enzymes, which were highly active in breast tumor tissues, were characterized. One of them, soluble tyrosine kinase-1 (STK-1), represents a soluble form of the c-Src protein, which is apparently underphosphorylated on its C-terminal tyrosine residue whereas the other (STK-2) is a 48-kDa protein tyrosine kinase (PTK), which is molecularly and functionally related to the C-terminal Src kinase (Csk). These two protein tyrosine kinases clearly exhibit a different substrate specificity, and are responsible for the high tyrosine kinase activity present in the cytosolic fraction of human breast cancer. In addition, it was observed that STK-1 and STK-2 are also expressed in the breast cancer cell line, CAL-51.
Carcinogenesis 1997 Aug
PMID:Characterization of two different cytoplasmic protein tyrosine kinases from human breast cancer. 927 17

Focal adhesion kinase (FAK) is a novel non-receptor protein tyrosine kinase implicated in transducing signals from cell surface receptors. Its association with Fyn, a member of the Src family of tyrosine kinases, has been observed in cell lines. To examine in vivo the interaction between these two proteins, Fyn-deficient mice were bred with fak heterozygous mutants (Fak deficiency is embryonic lethal). A majority of animals with the double mutation (fyn-/- fak+/-) displayed a transient impairment in thymocyte development at four weeks of age. However, all of them developed skin abnormalities at the age of 8-12 months. The most prominent among abnormalities was a greatly increased number and size of sebaceous glands. Also, the epidermis was thickened and hyperkeratotic. These observations would suggest involvement of Fyn and FAK in keratinocyte differentiation.
Carcinogenesis 1997 Aug
PMID:Skin abnormality in aged fyn-/- fak+/- mice. 927 18

The effects of combined administration of a catecholamine precursor, tyrosine methyl ester (TME), and an ornithine decarboxylase (ODC) inhibitor, 1,3-diaminopropane (DAP), on the incidence of gastric cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), the norepinephrine (NE) concentration and ODC activity of the gastric wall, and the labeling index of the gastric mucosa were investigated in inbred Wistar rats. Rats received s.c. injections of TME, 512 mg/kg body weight, every other day and drinking water with or without 2.5 g/l of DAP after 25 weeks of oral administration of MNNG. At week 52, administration of TME resulted in significant increases in the incidence of gastric cancers, in the NE concentration and the ODC activity of the antral portion of the gastric wall, and in the labeling index of antral epithelial cells. Administration of both TME and DAP significantly reduced the enhancements by TME of gastric carcinogenesis, NE concentration and ODC activity of the antral wall, and the labeling index of the antral mucosa. Our results suggest that ODC inhibition lessens enhancement by TME of gastric carcinogenesis and that the enhancement by TME of gastric carcinogenesis is mediated in part by polyamine biosynthesis.
 ...
PMID:Ornithine decarboxylase inhibitor lessens the rat gastric carcinogenesis enhancement caused by tyrosine methyl ester. 933 17

Normal dog gallbladder epithelial cells in long-term culture were used as a model to study the morphologic, genetic, and secretory processes associated with the progression to cancer formation. Dog gallbladder epithelial cells cultured on collagen-coated plates grew into polarized monolayers, could be passaged repeatedly, and showed the typical morphological profile of well-differentiated columnar epithelial cells. After cells were exposed to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) at 10(-5) mol/L for 48 hours, the treated cells grew on plastic and could be cloned. Flow cytometry revealed emergence of an aneuploid cell subpopulation. In organotypic culture, treated cells showed a pseudostratified appearance, with cellular and nuclear pleomorphism. Large and hyperchromatic nuclei were present as well as increased mitotic rate. The proteins of MNNG-treated dog gallbladder epithelial cells showed increased phosphorylation of tyrosine residues. Treated cells showed a decrease in mucin secretion in response to prostaglandin E2, manifesting an altered pattern of mucin secretion. Transforming growth factor-beta failed to inhibit cell proliferation in the MNNG-treated cells compared with the prominent inhibition in normal cells. Together, the data reflected changes representing preliminary steps on the pathway to develop cancer cells. Our results indicate that carcinogenic chemicals can cause measurable chromosomal and cellular modifications to normal biliary epithelial cells in vitro. This model may be useful in understanding the sequential steps in carcinogenesis and affords an opportunity to study chromosomal damage, cytokinetics, changes in molecular genetic markers, and expression, as well as cell biological function during cellular transformation.
 ...
PMID:The effect of N-methyl-N'-nitro-N-nitrosoguanidine on cultured dog gallbladder epithelial cells. 936 75

We reported recently that weight cycling significantly increased the incidence of mammary cancer in virgin female rats that were pretreated with N-methyl-N-nitrosourea. The present study investigated the effect of weight cycling on mammary epithelial cell proliferation and its relationship to changes in plasma insulin, estrogen, progesterone and urinary corticosterone in 30 female virgin Sprague-Dawley rats. Animals were fed a modified AIN-76A diet containing 24.6% corn oil by weight. Weight-cycled (WC) rats were food restricted daily by either 33% or 50% of non-restricted controls for 1 week followed by 3 weeks compensatory refeeding and weight recovery over 18 weeks or 4.5 weight cycles. WC rats consumed 6-10% less food than controls (P = 0.01) but showed a 71-89% greater efficiency of food utilization for growth (P < 0.0001) than controls. There were no differences in total weight gain during treatment. Mammary lobuloalveolar and ductal cell proliferation of WC rats, measured by 5-bromo-2'deoxyuridine labelling, increased in a dose-response fashion, P = 0.03, P = 0.06 respectively in comparison to controls. Energy and substrate utilization measured by indirect calorimetry indicated WC animals expended less energy (P = 0.005) and utilized less glucose (P = 0.0001) and protein (P = 0.006) during restriction, and less lipid during recovery (P = 0.05) than controls. There were no significant differences in hormone levels between groups. Multiple regression analysis with plasma insulin, estrogen, progesterone and urinary corticosterone as independent variables (r = 0.947, r2 = 0.897, P = 0.003) showed that plasma insulin was the only significant predictor (P < 0.01) of mammary cell proliferation. In accord with this observation, tyrosine-phosphorylated activation of insulin receptor substrate-1, detected by immunoprecipitation and Western immunoblot analysis in mammary tumors of WC rats from our previous study, was 3-5 times greater than in non-restricted controls (P < 0.01). Present findings suggest that weight cycling in rats increases risk of breast cancer development via insulin stimulated mammary cell proliferation.
Carcinogenesis 1997 Nov
PMID:Cyclic food restriction, insulin and mammary cell proliferation in the rat. 939 31

Phosphoinositide-specific phospholipase Cgamma (PLCgamma) is a key regulatory enzyme that binds to the phosphoryl-tyrosine residues in the cytoplasmic domain of certain activated receptors and catalyses the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] forming IP3 and diacylglycerol (DAG) in response to several mitogenic factors. Previously, we determined that microinjected PLCgamma induces DNA synthesis in G0-arrested NIH 3T3 cells, suggesting the possibility that PLCgamma may have an oncogenic potential. In this report, we demonstrate that overexpression of PLCgamma in NIH 3T3 cells results in altered growth properties and cellular transformation. The PLCgamma/3T3 transfectants do not require serum growth factors to proliferate, display anchorage-independent growth in soft agar and induce tumors when transplanted into nude mice. These findings suggest that overexpression of PLCgamma facilitates the transformation of NIH 3T3 cells. Furthermore, PLCgamma expression and activity have been shown to be elevated in many human tumors. Thus, PLCgamma signaling may contribute to the promotion and/or progression of human cancers.
Carcinogenesis 1998 Jan
PMID:Overexpression of phosphoinositide-specific phospholipase Cgamma in NIH 3T3 cells promotes transformation and tumorigenicity. 947 10

Exposure to ultraviolet radiation of solar light is responsible for inflammation, premature skin aging and is the main cause of human skin carcinogenesis. While the noxious consequences of U.V. exposure are known, the molecular events triggered by this radiation are poorly understood. We observed that U.V.-A and U.V.-B irradiation of human keratinocytes induces the activation of tyrosine kinase pathways leading to the tyrosine phosphorylation of several cellular proteins. We also observed a stimulation of the Stress Activated Protein kinases (SAPKs), p38 and JNK, and an activation of the transcription factors AP-1 in response to U.V.-A and U.V.-B radiation. Furthermore, we clearly demonstrated that physiological U.V. doses are able to activate the Extracellular signal-Regulated Kinases, ERK1 and ERK2, which could explain the activation of the Ternary Complex Factor. Thus, in human keratinocytes, solar U.V. light activates multiple signalling pathways that could be involved in skin inflammation following U.V.-induced skin injury or in U.V.-induced skin carcinogenesis.
 ...
PMID:Solar ultraviolet light activates extracellular signal-regulated kinases and the ternary complex factor in human normal keratinocytes. 948 12

We examined 13 human gastric carcinoma cell lines for the expression of both c-kit and stem cell factor (SCF). Expression of mRNAs was detected by both Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR), and expression of translated proteins was detected by western blotting. Using RT-PCR we confirmed the expression of c-kit in five (ECC12, TMK1, MKN7, GCIY, and HGC27) cell lines. Northern blot analysis showed coexpression of both c-kit and SCF in ECC12 and expression of SCF in five other (MKN74, MKN1 OKAJIMA, KATOIII, and TMK1) cell lines. SCF stimulated both tyrosine phosphorylation of c-kit and growth of ECC12, whereas it did not stimulate those of GCIY. The sizes of c-kit transcript and protein in GCIY were slightly smaller than those of the reported ones, suggesting the presence of a biologically inactive truncated form of c-kit in GCIY. The present study suggests that c-kit/SCF system might play an important role in the carcinogenesis and tumor growth of ECC12 and that the truncated form of c-kit in GCIY might not be associated with malignant transformation.
 ...
PMID:Expression of protooncogene c-kit and its ligand stem cell factor (SCF) in gastric carcinoma cell lines. 950 39

This study was designed to test the chemopreventive potential of perillyl alcohol, an inhibitor of farnesyltransferase, in a mouse lung tumor bioassay. Perillyl alcohol is a naturally occurring monoterpene found in lavender, cherries, and mint. We have shown previously that the majority of lung tumors in this bioassay have an activating mutation in the K-ras gene, which occurs early in the development of mouse lung carcinogenesis. The Ras protein undergoes a series of post-translational modifications, the first of which is farnesylation at the cysteine of the C-terminal CAAX motif. These modifications lead to the anchoring of Ras p21 to the plasma membrane in its biologically active state. Activated Ras p21 couples growth regulatory signals from receptor tyrosine kinases to cytoplasmic second messengers. In a preliminary study, we determined the maximum tolerated dose of perillyl alcohol to be 75 mg/kg body weight. For the bioassay, 5-week-old male (C3H/HeJ X A/J) F1 hybrid mice were randomized into trial groups, and treated with perillyl alcohol three times per week i.p., starting 1 week prior to initiation with the carcinogen NNK, and continuing for 22 weeks after initiation. Our results show a 22% reduction in tumor incidence, and a 58% reduction in tumor multiplicity. Our study demonstrates that perillyl alcohol is an effective chemopreventive compound in the mouse lung tumor bioassay.
 ...
PMID:Chemopreventive effect of perillyl alcohol on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induced tumorigenesis in (C3H/HeJ X A/J)F1 mouse lung. 959 Nov 89


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>