transforming-growth-factor-alpha and Body-Weight

Adropin is a peptide hormone that has been implicated in insulin resistance and as a potential regulator of growth. The aim of this study is to determine the effect of calorie restriction on circulating levels of adropin in the MMTV-TGFα breast cancer mouse model and investigate the effects of adropin peptide on the viability of MCF-7 and MDA-231 breast cancer cells in culture. Ten-week-old mice were assigned to either ad libitum-fed (AL), chronic calorie-restricted, or intermittent calorie-restricted groups. Concentrations of serum adropin were measured using an enzyme-linked immunosorbent assay. Results showed an inverse correlation between serum adropin levels and mouse age that was attenuated by calorie restriction. In the AL group the level of adropin was significantly lower at week 50 compared to levels at week 10. However, among the calorie-restricted groups, serum levels of adropin remained high at week 50. The cell-line-specific effects were observed after treatment of cancer cell lines with a series of adropin concentrations (5, 10, 25, 50 ng/mL). Flow cytometry analysis showed that MCF-7 cells entered the early phase of apoptosis after treatment with 50 ng/mL for 24 h. Adropin may be involved in the protective effects that calorie restriction has on breast cancer risk.

Topics: Age Factors; Animals; Apoptosis; Blood Proteins; Body Weight; Breast Neoplasms; Caloric Restriction; Cell Line, Tumor; Cell Survival; Female; Humans; Intercellular Signaling Peptides and Proteins; Male; MCF-7 Cells; Mice, Inbred C57BL; Mice, Transgenic; Proteins; Transforming Growth Factor alpha

Gene expression of epidermal growth factor (EGF), transforming growth factor-α (TGF-α) and EGF receptor (EGF-R) and the localization of the corresponding proteins in the canine testis were studied. Levels of mRNA expressions were determined by semiquantitative reverse transcription polymerase chain reaction in the testes of the peripubertal (4-6 months), young adult (3-4 years), advanced adult (7-8 years) and senescent (11-16 years) groups. The EGF-R mRNA level in the testes of the peripubertal group was significantly higher than those in the other groups, whereas there was no difference in EGF and TGF-α mRNA levels among groups. Immunohistochemical stainings for EGF, TGF-α and EGF-R in the testis revealed that immunoreactivity in the seminiferous epithelium and Sertoli cell was weak and nonspecific for the stage of spermatogenesis, and distinct staining was found in Leydig cells. These results suggest that the EGF family of growth factors may be involved in testicular maturation and function in the dog.

Topics: Animals; Body Weight; Dogs; Epidermal Growth Factor; ErbB Receptors; Gene Expression Regulation; Immunohistochemistry; Leydig Cells; Male; RNA, Messenger; Seminiferous Epithelium; Sertoli Cells; Testis; Transforming Growth Factor alpha

Previously we reported that intermittent calorie restriction (ICR) provided greater prevention of mammary tumors (MTs) than chronic calorie restriction (CCR). Here the impact of increased fat intake during refeeding in an ICR protocol was evaluated. MMTV-TGF-α female mice were assigned to one of three groups: ad libitum (AL) fed (n = 45) with free access to a moderately high fat diet (22 % fat calories); ICR (n = 45) 50 % calorie restricted for 3-week intervals followed by 3 weeks of 100 % of AL intake; and CCR (n = 45) fed 75 % of AL mice, matching each 6-week cycle of ICR mice. ICR mice were further designated as ICR-Restricted or ICR-Refed for data obtained during these intervals. All mice consumed the same absolute amount of dietary fat. Mice were followed to assess MT incidence, body weight and serum IGF-1, IGFBP3, leptin and adiponectin levels until 79 (end of final 3-week restriction) or 82 (end of final 3-weeks refeeding) weeks of age. Age of MT detection was significantly extended for CCR (74 weeks) and ICR (82 weeks) mice, compared to 57.5 weeks for AL mice. MT incidence for AL, ICR and CCR mice was 66.7, 4.4, and 52.3 %, respectively. Mammary and fat pad weights were reduced significantly following 50 % calorie restriction in ICR-Restricted mice compared to AL, CCR and ICR-Refed mice. IGF-1 and leptin levels also tended to be reduced in ICR-Restricted mice over the course of the study while adiponectin was not compared to AL, CCR, and ICR-Refed mice. The adiponectin:leptin ratio was consistently higher following 50 % restriction in ICR-Restricted mice. There was no relationship of IGF-1, leptin, or adiponectin with the presence of MTs in any groups. Thus the manner in which calories are restricted impacts the protective effect of calorie restriction independently of high fat intake.

Topics: Adiponectin; Adipose Tissue; Animals; Body Weight; Caloric Restriction; Cell Transformation, Neoplastic; Diet, High-Fat; Eating; Female; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Leptin; Mammary Neoplasms, Experimental; Mice; Mice, Transgenic; Transforming Growth Factor alpha

Although mounting evidence implicates mesenchymal stem cells (MSCs) in intestinal tissue repair, uncertainty remains concerning the distribution, function, and fate of repopulating MSCs in recipient colonic tissues. Therefore, we investigated the role of transplanted MSCs in the repair phase of DSS colitis.. LacZ-labeled rat MSCs were transplanted into rats with colitis induced by 4% DSS on day 2. Regular water replaced the DSS solution on day 6. Therapeutic effect was evaluated on day 9 by clinicopathologic and growth factor/cytokine expression profiles. We analyzed the Notch signaling pathway by Western blotting and characterized immunofluorescence of lacZ-labeled MSCs with confocal laser microscopy. In vivo differentiation of MSC was confirmed by transmission electron microscopy (TEM).. Recovery of colitis was modestly but significantly promoted by MSC transplantation due to proceeding cell cycle and inhibiting apoptosis in the epithelia. Tgfa mRNA expression increased significantly, while Notch signaling was inhibited in the colonic tissues with MSC transplantation. β-Galactosidase-positive cells, which expressed α-SMA, desmin, and vimentin, were infrequently detected in the lamina propria stroma. DSS exposure in vitro proved to be the most potent inducer for α-SMA in MSCs where TEM demonstrated myogenic lineage differentiation.. We found that MSCs transplantation modestly promoted the repair of DSS colitis. The donor-derived MSCs were likely reprogrammed to differentiate to myogenic lineage cells by cues from the micro milieu. Further characterization of these cells is warranted as a basis for applying cell-based therapy for inflammatory bowel disease.

Topics: Actins; Analysis of Variance; Animals; Apoptosis; beta-Galactosidase; Body Weight; Cell Cycle; Cell Differentiation; Cell Lineage; Colitis; Colon; Cytokines; Desmin; Dextran Sulfate; Disease Models, Animal; Intestinal Mucosa; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Rats; Rats, Inbred Lew; RNA, Messenger; Signal Transduction; Transforming Growth Factor alpha; Vimentin

Chronic calorie restriction (CCR) prevents mammary tumor (MT) development in rodents. We reported that intermittent calorie restriction (ICR) provides greater protection than CCR in MMTV-TGF-α mice. The mammalian target of rapamycin (mTOR) pathway is involved in MT development. Here the impact of ICR versus CCR on proteins associated with mTOR signaling in mammary tissues and MTs from MMTV-TGF-α mice was determined. Mice were enrolled at 10 wk of age into ad libitum-fed (AL), CCR, and ICR groups and followed until 37/38 or 73/74 wk of age. Time points 37 and 73 followed 3 wk of 50% restriction for ICR mice, while 38 and 74 followed 1 wk of refeeding of ICR mice. Calorie restriction reduced serum IGF-I levels except for older CCR mice. At 37/38 wk, calorie restriction decreased mTOR, p70S6K, HIF-1, EGFR, and Erk protein activation and increased p4EBP1 and VEGF in mammary fat pads. At 73/74 wk, both modes of calorie restriction lowered IGF-I protein expression levels and Akt activation in MTs and mammary fat pads, and CCR increased mTOR, p70S6K, p4EBP1, and HIF-1 expression. ICR had inconsistent effects on these proteins in older mice. These results indicate that mTOR signaling proteins are modulated by age and type of calorie restriction.

Topics: Adipose Tissue; Analysis of Variance; Animals; Body Weight; Breast; Caloric Restriction; Cell Line, Tumor; Disease Models, Animal; Eating; Energy Intake; Female; Humans; Insulin-Like Growth Factor I; Mammals; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Inbred C57BL; Mice, Transgenic; Signal Transduction; TOR Serine-Threonine Kinases; Transforming Growth Factor alpha

The effect of chronic (CCR) and intermittent (ICR) caloric restriction on serum insulin-like growth factor (IGF)-I levels and mammary tumor (MT) development was investigated. Ten-week-old MMTV-TGF-alpha female mice were assigned to ad libitum-fed (AL; AIN-93M diet), ICR [3-week 50% caloric restriction using AIN-93M-mod diet, 2x protein, fat, vitamins, and minerals followed by 3 weeks of daily 100% AL consumption of AIN-93M ( approximately 75% of AL for each 6-week cycle)], and CCR (calorie and nutrient intake matched for each 6-week ICR cycle) groups. Half of the mice from each group were sacrificed at 79 (end of restriction) or 82 (end of refeeding) weeks of age. Serum was obtained at euthanasia and in cycles 1, 3, 5, 8, and 11. MT incidence was 71.0%, 35.4%, and 9.1% for AL, CCR, and ICR mice. ICR-Restricted mice had significantly lower terminal serum IGF-I and IGF-I/IGF binding protein-3 (IGFBP-3) ratio than CCR, ICR-Refed, and AL mice. There were no differences in terminal IGFBP-3. Final body, internal, and mammary fat pad weights correlated positively with IGF-I and negatively with IGFBP-3. Few changes were found for protein expression of IGF-IRalpha and IGFBP-3 in mammary tissue and MTs. During the study, IGF-I levels of ICR-Restricted mice were reduced, whereas refeeding allowed partial recovery. For all groups, elevated IGF-I levels preceded MT detection, although not all values were significant versus mice without MTs. However, the specific role of IGF-I in the protective effect of calorie restriction remains to be determined. These results confirm that ICR prevents MT development to a greater extent than CCR.

Topics: Adipose Tissue; Animals; Body Weight; Caloric Restriction; Carcinoma; Eating; Female; Insulin-Like Growth Factor I; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Inbred ICR; Mice, Transgenic; Periodicity; Time Factors; Transforming Growth Factor alpha; Transgenes

Chronic caloric restriction (CCR) prevents mammary tumorigenesis in rodents, but a protective effect for intermittent caloric restriction (ICR) is less well documented. We recently reported that ICR reduced mammary tumor (MT) incidence of mouse mammary tumor virus-transforming growth factor (MMTV-TGF)-alpha mice to a greater extent than did CCR. Here, we repeated this protocol and obtained serum and tissue samples. Ad libitum (AL) MMTV-TGF-alpha mice were fed AIN-93M diet. Beginning at 10 weeks of age, ICR mice received isocaloric AIN-93M-mod diet (2-fold increases in protein, fat, vitamins, and minerals) at 50% of ad libitum for 3 weeks followed by 3 weeks refeeding with AIN-93M diet. CCR mice were pair-fed AIN-93M:AIN-93M-mod (2:1) matching intakes for restriction/refeeding cycles. Mice were sacrificed for MT size, at 79 (end of 12th restriction) or at 80 (1 week after 12th refeeding) weeks of age. AL and ICR-80 mice had heavier body weights than ICR-79 and CCR mice (P < 0.0001). Cumulative food intakes of ICR and CCR mice were reduced 12% and 15% versus AL mice (P < 0.0001). However, ICR mice consumed significantly (P < 0.0001) more food than did AL mice during refeeding. MT incidence was 84%, 13%, and 27% for AL, ICR, and CCR mice, respectively. MT weight (P < 0.0011) and number (P < 0.01) were higher for AL mice compared with ICR and CCR mice. AL and ICR-80 mice had similar serum IGF-I levels, but only AL values were higher than those of ICR-79 and CCR mice (P < 0.0017). ICR mice had more MT DNA breaks compared with AL and CCR mice, suggesting enhanced apoptosis (P < 0.02). AL mice had higher mammary fat pad ObR and ObRb leptin receptor mRNA expression than did ICR and CCR mice (P < 0.001), but there was no effect on MTs. These results confirm that ICR prevents development of MTs to a greater extent than does CCR, although "overeating" during refeeding may compromise this protection.

Topics: Animals; Body Weight; Caloric Restriction; Diet; DNA Breaks; Energy Intake; Female; Gene Expression; Incidence; Insulin-Like Growth Factor I; Mammary Neoplasms, Animal; Mice; Mice, Transgenic; Receptors, Cell Surface; Receptors, Leptin; RNA, Messenger; Transforming Growth Factor alpha

Transforming growth factor-alpha (TGF-alpha) and its receptor, the epithelial growth factor receptor (EGFR), have been associated with lung remodeling in premature infants with bronchopulmonary dysplasia (BPD). The goal of this study was to target TGF-alpha overexpression to the saccular phase of lung morphogenesis and determine early alterations in gene expression. Conditional lung-specific TGF-alpha bitransgenic mice and single-transgene control mice were generated. TGF-alpha overexpression was induced by doxycycline (Dox) treatment from embryonic day 16.5 (E16.5) to E18.5. After birth, all bitransgenic pups died by postnatal day 7 (P7). Lung histology at E18.5 and P1 showed abnormal lung morphogenesis in bitransgenic mice, characterized by mesenchymal thickening, vascular remodeling, and poor apposition of capillaries to distal air spaces. Surfactant levels (saturated phosphatidylcholine) were not reduced in bitransgenic mice. Microarray analysis was performed after 1 or 2 days of Dox treatment during the saccular (E17.5, E18.5) and alveolar phases (P4, P5) to identify genes induced by EGFR signaling that were shared or unique to each phase. We found 196 genes to be altered (>1.5-fold change; P < 0.01 for at least 2 time points), with only 32% similarly altered in both saccular and alveolar phases. Western blot analysis and immunostaining showed that five genes selected from the microarrays (egr-1, SP-B, SP-D, S100A4, and pleiotrophin) were also increased at the protein level. Pathological changes in TGF-alpha-overexpressing mice bore similarities to premature infants born in the saccular phase who develop BPD, including remodeling of the distal lung septae and arteries.

Topics: Animals; Body Weight; Bronchopulmonary Dysplasia; Cell Differentiation; ErbB Receptors; Gene Expression Profiling; Gene Expression Regulation, Developmental; Humans; Infant, Newborn; Mice; Mice, Transgenic; Microscopy, Electron, Transmission; Myocardium; Oligonucleotide Array Sequence Analysis; Organ Size; Pulmonary Alveoli; Rats; Respiratory Mucosa; Transcription, Genetic; Transforming Growth Factor alpha

Obesity is a risk factor for postmenopausal breast cancer and is associated with shortened mammary tumor (MT) latency in MMTV-TGF-alpha mice with dietary-induced obesity. One link between obesity and breast cancer is the adipokine, leptin. Here, the focus is on diet-induced obesity and MT and mammary fat pad (MFP) leptin and apoptotic signaling proteins.. MMTV-TGF-alpha mice were fed low-fat or high-fat diets from 10 to 85 weeks of age. High-Fat mice were divided into Obesity-Prone and Obesity-Resistant groups based on final body weights. Mice were followed to assess MT development and obtain serum, MFP, and MT.. Incidence of palpable MTs was significantly different: Obesity-Prone > Obesity-Resistant > Low-Fat. Serum leptin was significantly higher in Obesity-Prone compared with Obesity-Resistant and Low-Fat mice. Low-Fat mice had higher MFP and MT ObRb (leptin receptor) protein and Jak2 (Janus kinase 2) protein and mRNA levels in comparison with High-Fat mice regardless of body weight. Leptin (mRNA) and pSTAT3 (phosphorylated signal transducer and activator of transcription 3) (mRNA and protein) also were higher in MTs from Low-Fat versus High-Fat mice. Expression of MT and MFP pro-apoptotic proteins was higher in Low-Fat versus High-Fat mice.. These results confirm a connection between body weight and MT development and between body weight and serum leptin levels. However, diet impacts MT and MFP leptin and apoptosis signaling proteins independently of body weight.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Blotting, Western; Body Weight; Densitometry; Dietary Fats; Female; Janus Kinase 2; Leptin; Mammary Neoplasms, Experimental; Mice; Obesity; Receptors, Leptin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Transforming Growth Factor alpha

Transforming growth factor-alpha (TGF-alpha) is abnormally expressed in autosomal recessive polycystic kidney disease (ARPKD). Tumor necrosis factor-alpha converting enzyme (TACE), a metalloproteinase, mediates TGF-alpha processing. In this study, we sought to determine whether TGF-alpha was an absolute requirement for renal cystogenesis and whether its absence would modulate disease severity or related growth factors/receptors expression. Bpk heterozygotes were bred with TGF-alpha null mice to produce cystic and noncystic offspring with or without TGF-alpha. Assessments included kidney weight (KW), body weight (BW), blood urea nitrogen (BUN), and kidney and liver immunohistology. Western analysis assessed kidney expression of amphiregulin (AR), epidermal growth factor (EGF), heparin-binding EGF (HB-EGF), and their receptors, EGFR and ErbB4. A PCR-based methodology for genotyping bpk mice was also developed. No significant differences in KW, BW, KW/BW%, or BUN were seen in cystic mice with versus without TGF-alpha. Cystic kidney disease and liver disease histology were similar. AR, EGF, HB-EGF, EGFR, and ErbB4 were abnormally expressed to an equal degree in kidneys of mice with versus without TGF-alpha. Although previous data suggest a critical role of TGF-alpha in murine PKD, these data show that TGF-alpha is not required for renal cyst formation or kidney or liver disease progression. We speculate that the therapeutic effect of WTACE2 could have been due to effects on several TACE targets, including TGF-alpha, AR, and ErbB4, as well as metalloproteinases other than TACE.

Topics: ADAM Proteins; ADAM17 Protein; Alleles; Amphiregulin; Animals; Blood Urea Nitrogen; Body Weight; Disease Progression; EGF Family of Proteins; Epidermal Growth Factor; ErbB Receptors; Genes, Recessive; Genotype; Glycoproteins; Heparin-binding EGF-like Growth Factor; Intercellular Signaling Peptides and Proteins; Kidney; Kidney Diseases, Cystic; Liver; Metalloendopeptidases; Mice; Mice, Inbred C57BL; Mutation; Organ Size; Phenotype; Polycystic Kidney Diseases; Polymerase Chain Reaction; Receptor, ErbB-4; Transforming Growth Factor alpha

Being overweight is a risk factor for postmenopausal breast cancer and is associated with an increased incidence and shortened latency of spontaneous and chemically induced mammary tumors in rodents. However, leptin-deficient obese Lep(ob)Lep(ob) female mice have reduced incidences of spontaneous and oncogene-induced mammary tumors. Of interest, leptin enhances the proliferation of human breast cancer cell lines in which leptin receptors are expressed, which suggests that leptin signaling plays a role in tumor development. We evaluated oncogene-induced mammary tumor development in obese MMTV-TGF-alpha/Lepr(db)Lepr(db) mice that exhibit a defect in OB-Rb, which is considered to be the major signaling isoform of the leptin receptor. Lepr and MMTV-TGF-alpha mice were crossed, and the offspring were genotyped for oncogene expression and the determination of Lepr status. Lean MMTV-TGF-alpha/Lepr(+)Lepr(+) (homozygous) and MMTV-TGF-alpha/Lepr(+)Lepr(db) (heterozygous) mice and obese MMTV-TGF-alpha/Lepr(db)Lepr(db) mice were monitored until age 104 weeks. Body weights of MMTV-TGF-alpha/ Lepr(db)Lepr(db) mice were significantly heavier than those of the lean groups. No mammary tumors were detected in MMTV-TGF-alpha/Lepr(db)Lepr(db) mice, whereas the incidence of mammary tumors in MMTV-TGF-alpha/Lepr(+)Lepr(+) and MMTV-TGF-alpha/ Lepr(+)Lepr(db) mice was 69% and 82%, respectively. Examination of mammary tissue whole mounts indicated an absence of duct formation and branching for MMTV-TGF-alpha/Lepr(db)Lepr(db) mice. Both age at mammary tumor detection and tumor burden (tumors/mouse and tumor weights) were similar for the lean genotypes. Serum leptin levels of MMTV-TGF-alpha/Lepr(db)Lepr(db) mice were 12-20-fold higher than levels of lean mice. Thus, despite elevated serum leptin levels, leptin receptor-deficient MMTV-TGF-alpha/Lepr(db)Lepr(db) mice do not develop mammary tumors. This study provides additional evidence that leptin and its cognate receptor may be involved in mammary tumorigenesis.

Topics: Animals; Body Weight; Disease Models, Animal; Female; Leptin; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Obesity; Oncogenes; Receptors, Cell Surface; Receptors, Leptin; Survival Analysis; Transforming Growth Factor alpha

Elevated body weight is a risk factor for postmenopausal breast cancer and is associated with increased incidence of spontaneous and chemically induced mammary tumors (MTs) in rodents. In this study, genetically obese Lep(ob)Lep(ob) female mice that overexpress human TGF-alpha (transforming growth factor-alpha) were used to assess the role of body weight on oncogene-induced MT development in comparison to lean counterparts. MMTV (mouse mammary tumor virus)-TGF-alpha and Lep strain mice were crossed to produce TGF-alpha/Lep(+)Lep(+) (homozygous lean), TGF-alpha/Lep(+)Lep(ob) (heterozygous lean) and TGF-alpha/Lep(ob)Lep(ob) (homozygous obese) genotypes. Body weights were determined weekly and mice palpated for the presence of MTs until 104 weeks of age. Despite their significantly higher body weight, obese TGF-alpha/Lep(ob)Lep(ob) mice failed to develop MTs. MTs were detected between 48 and 104 weeks of age for 26/39 TGF-alpha/Lep(+)Lep(ob) mice and for 19/38 TGF-alpha/Lep(+)Lep(+) mice between 67 and 104 weeks of age. Although MT incidence was not statistically different between the lean groups, age of MT detection tended to be younger for TGF-alpha/Lep(+)Lep(ob) mice (p < 0.09). There were significant effects of both genotype and MTs on final body weight, that is, TGF-alpha/Lep(+)Lep(ob) mice weighed more than homozygous lean mice, and mice with MTs weighed more than those without MTs. TGF-alpha/Lep(ob)Lep(ob) mice are not a good model to evaluate the effect of body weight on MT development possibly due to leptin deficiency. However, the finding that increased body weight is associated with increased oncogene-induced MT development within the normal weight range provides experimental support for the role of body weight in breast cancer.

Topics: Animals; Body Weight; Disease Models, Animal; DNA Primers; Female; Leptin; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Polymerase Chain Reaction; Survival Analysis; Transforming Growth Factor alpha

The chemopreventive potential of an Agaricus blazei (Ab) Murrill mushroom meal was investigated in a medium-term rat liver carcinogenesis assay. Male Wistar rats initiated for hepatocarcinogenesis with diethylnitrosamine (DEN, 200 mg/kg i.p.) were fed during a 6-week period with the dry powdered mushroom strains Ab 29 or 26, each one with opened (OB) or closed basidiocarp (CB), mixed at 10% level in a basal diet. All experimental animals and controls were subjected to partial hepatectomy at week 3 and killed at week 8. Chemopreventive activity of the mushroom meal was observed for the Ab 29 (OB and CB) and Ab 26 (CB) strains in terms of the number of putative preneoplastic altered foci of hepatocytes which express either the enzyme glutathione S-transferase, placental form (GST-P+) or the transforming growth factor-alpha, and for the Ab 29 (OB) and Ab 26 (CB) strains on the size of GST-P+ foci. This was associated with inhibition of foci cell proliferation in the animals fed the Ab 29 (OB) and Ab 26 (CB) strains. The results suggest that the protective influence of the Ab meal against the DEN potential for rat liver carcinogenicity depends on both the strain and period of mushroom harvest.

Topics: Agaricus; Animals; Anticarcinogenic Agents; Body Weight; Carcinogens; Diet; Diethylnitrosamine; Eating; Glutathione Peroxidase; Immunohistochemistry; Liver; Liver Neoplasms, Experimental; Male; Organ Size; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Rats; Rats, Wistar; Transforming Growth Factor alpha; Weight Gain

TGF-alpha has recently been shown to stimulate enterocyte proliferation. In the present study we investigated the effect of TGF-alpha on enterocyte proliferation and loss via apoptosis and its effects on intestinal adaptation in a rat following massive bowel resection.. Male Sprague-Dawley rats underwent bowel transection and reanastomosis (sham group) or 75% small bowel resection and anastomosis (SBS group) and were treated with intraperitoneal TGF-alpha (75 microg/kg) from the ninth postoperative day (SBS-TGF-alpha group). Parameters of intestinal adaptation (overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth), enterocyte proliferation, and apoptosis were determined on day 15. Statistical significance was determined by ANOVA with a P < 0.05 considered significant.. SBS-TGF-alpha rats demonstrated a significant increase (vs SBS) in duodenal, jejunal, and ileal overall bowel and mucosal weights; ileal mucosal DNA and protein; and jejunal and ileal villus height. SBS-TGF-alpha rats also showed an increased cell proliferation index in jejunum (704 +/- 43 vs 499 +/- 63 BrdU-positive cells/10 crypts, P < 0.05) and ileum (715 +/- 84 vs 529 +/- 40 BrdU-positive cells/10 crypts, P < 0.05) and decreased apoptotic index in ileum (8.7 +/- 1.1 vs 21.8 +/- 3.2 apoptotic cells/1,000 villus cells, P < 0.05) compared to SBS animals.. In a rat model of SBS, TGF-alpha enhances intestinal adaptation. Possible mechanisms may include increased cell proliferation and decreased enterocyte loss via apoptosis.

Topics: Adaptation, Physiological; Animals; Apoptosis; Body Weight; Cell Division; DNA; Intestinal Mucosa; Intestine, Small; Male; Organ Size; Proteins; Rats; Rats, Sprague-Dawley; Short Bowel Syndrome; Transforming Growth Factor alpha

Transgenic mice that overexpress transforming growth factor (TGF)-alpha develop liver tumors between 12 and 15 months of age. Tumor development is preceded by an overall increase in the rates of hepatocyte proliferation and cell death. To examine the role of apoptosis in the development of TGF-alpha-induced liver tumors, we generated TGF-alpha/Bcl-2 double transgenic mice by crossing TGF-alpha transgenic mice with Bcl-2 transgenic mice expressing a zinc-inducible Bcl-2 transgene. Overexpression of the Bcl-2 transgene protected hepatocytes from Fas-mediated apoptosis. We anticipated that hepatocytes in TGF-alpha/Bcl-2 double transgenic mice would be stimulated to proliferate but would fail to undergo apoptosis, leading to increased liver weights and accelerated tumorigenesis. At 4 weeks of age, both TGF-alpha single transgenic and TGF-alpha/Bcl-2 double transgenic mice had elevated hepatocyte proliferation and increased liver:body weight ratios. However, by 8 months, the liver:body weight ratios had normalized in both TGF-alpha single transgenic and TGF-alpha/Bcl-2 double transgenic mice. Furthermore, Bcl-2 functioned as a tumor suppressor, significantly decreasing the frequency and delaying the development of TGF-alpha-induced liver tumors, despite having comparable levels of TGF-alpha transgene expression in both single and double transgenic mice. Between 11 and 12 months of age, >80% of the TGF-alpha single transgenic mice had developed tumors, whereas only 54% of the double transgenic mice had developed tumors after 13 months of age. The tumors that eventually developed in the TGF-alpha/Bcl-2 double transgenic mice were histologically distinct and smaller in size and had lower hepatocyte mitotic activity than tumors from TGF-alpha single transgenic mice. Furthermore, delaying Bcl-2 expression until 8.5 months of age was sufficient to inhibit TGF-alpha-induced tumorigenesis. These results indicate that Bcl-2 inhibits tumor progression in the liver, possibly by interfering with hepatocyte proliferation.

Topics: Animals; Apoptosis; Blotting, Northern; Blotting, Western; Body Weight; Cell Division; fas Receptor; Female; Gene Expression Regulation; Gene Expression Regulation, Neoplastic; Genotype; Hepatocytes; Humans; Liver; Liver Neoplasms; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Organ Size; Proto-Oncogene Proteins c-bcl-2; Time Factors; Transforming Growth Factor alpha; Transgenes

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure produces hydronephrosis and cleft palate in mice. These responses are correlated with disruption of expression of epidermal growth factor (EGF) receptor ligands, primarily EGF and transforming growth factor-alpha (TGF-alpha), and altered epithelial cell proliferation and differentiation. This research examined the role of these growth factors in TCDD-induced teratogenicity by using wild type (WT) and knockout (-/-) mice that do not express EGF, TGF-alpha, or both EGF and TGF-alpha. Pregnant females were weighed on GD 12 and dosed by gavage with either corn oil or TCDD at 24 microg/kg, 5 ml/kg. On GD 17.5, the maternal parameters evaluated included body weight, body weight gain, liver weight (absolute and adjusted for body weight). The number of implantations, live and dead fetuses, early or late resorptions, the proportion of males, fetal body weight, fetal absolute and relative liver weight, placenta weight, incidence of cleft palate, and the severity and incidence of hydronephrosis were recorded. TCDD did not affect maternal weight gain, fetal weight, or survival, but maternal and fetal liver weights and liver-to-body weight ratios were increased in all genotypes. The WT and TGF-alpha (-/-), but not the EGF (-/-) and EGF + TGF-alpha (-/-) fetuses, developed cleft palate after exposure to 24 microg TCDD/kg. Hydronephrosis was induced by TCDD in all genotypes, with the incidence in EGF + TGF-alpha (-/-) fetuses comparable to that of the WT. The incidence and severity of this defect was substantially increased in EGF (-/-) and TGF-alpha (-/-). In conclusion, this study demonstrated that expression of EGF influences the induction of cleft palate by TCDD. Also, EGF and TGF-alpha are not required for the induction of hydronephrosis, but when either is absent the response of the fetal urinary tract to TCDD is enhanced.

Topics: Abnormalities, Drug-Induced; Administration, Oral; Animals; Body Weight; Cleft Palate; Environmental Pollutants; Epidermal Growth Factor; Female; Hydronephrosis; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Organ Size; Polychlorinated Dibenzodioxins; Pregnancy; Reproduction; Teratogens; Toxicity Tests; Transforming Growth Factor alpha

Epidermal growth factor (EGF) is present in milk from various mammalian species, but its physiologic function in neonatal development remains unclear. Transforming growth factor-alpha (TGF-alpha) is a peptide structurally related to EGF, and its presence is detected in the developing small intestine of rats. The purpose of the present study was to examine the effect of milk-borne EGF on endogenous production of EGF and TGF-alpha in the small intestine of suckling rats. Neonatal rats were fed via gastrostomy either growth factor-free rat milk substitute (RMS) or RMS supplemented with EGF (100 ng/mL of RMS) from 8 to 12 d of age. Artificially reared rats were then compared with their dam-fed littermates. Animals fed the EGF-deficient diet RMS had markedly increased EGF and TGF-alpha mRNA levels in duodenum and ileum compared with dam-fed controls and significantly elevated total intestinal content of TGF-alpha peptide. Intestinal EGF content and EGF serum levels were significantly decreased in the RMS group compared with controls. The addition of EGF to the RMS diet normalized TGF-alpha mRNA levels in the duodenum and ileum, EGF mRNA levels in the ileum, and total intestinal TGF-alpha content and EGF serum levels to the levels measured in dam-fed littermates. Motility studies showed that enteral administration of EGF did not affect stomach emptying and intestinal transit. These studies indicate that exogenous milk-borne EGF modulates endogenous production of TGF-alpha in developing small intestine. It is likely that neither TGF-alpha nor EGF are solely responsible for small intestinal overgrowth of artificially reared neonatal rats.

Topics: Animals; Animals, Newborn; Body Weight; Epidermal Growth Factor; Female; Gastrointestinal Motility; Intestine, Small; Male; Milk; Rats; Rats, Sprague-Dawley; Transforming Growth Factor alpha

Sex difference has been shown to play a major role in susceptibility to the development of hepatocellular carcinoma in humans and rodents. In order to clarify the necessity of androgens in hepatic tumorigenesis in transgenic mice overexpressing transforming growth factor (TGF) alpha (MT42), androgen supplement after castration and the LH-RH analogue, leuprolerin acetate, were tested in an experimental model in MT42.. Male MT42 mice were castrated and supplemented with dihydrotestosterone (DHT) every three months up to 15 months and hepatic tumorigenesis was observed. Leuprolerin acetate was administered to both male and female MT42 mice once a month from 2 months after birth to 15 months to observe the effect on hepatic tumorigenesis. Northern hybridization was performed to detect messenger RNA (mRNA) of TGFalpha expression and the rate of proliferative cell nuclear antigen (PCNA) staining compared with the castrated and non-treated mice.. Castration tended to decrease both body and liver weight in MT42 mice which was then restored by DHT. Untreated MT42 males developed 11 liver tumors in 6 mice. Hormonal treatment including castration and DHT supplementation did not change the expression of TGFalpha-mRNA. Castrated transgenic mice developed 2 liver tumors in 2 out of 6 mice and DHT supplementation after castration restored the number of liver tumors to 9 in 5 of 6 mice. PCNA labelling indexes of liver tumors and adjacent non-tumorous-liver were 7.1% (p<0.05): 0.6% in untreated MT42, 3.2%: 0.2% in castrated MT42 and 10.1% (p<0.05): 0.5% in MT42 with castration and DHT supplementation (significant difference compared with castrated mice). Leuprolerin acetate-treated MT42 males developed one liver tumor in 6 mice compared to MT42 administered with saline as a vehicle control in which group 7 liver tumors in 6 male MT42 were observed. Tumors in castrated-MT42 and leuprolerin treated-MT42 were smaller than those in control MT42 mice.. TGFalpha related hepatocarcinogenesis and hepatocyte proliferation are increased by androgenic stimulation. Suppression of androgens may be useful for the treatment of TGFalpha related liver tumors.

Topics: Animals; Blotting, Northern; Body Weight; Carcinoma, Hepatocellular; Cell Division; Dihydrotestosterone; Disease Models, Animal; Female; Gene Expression; Hormone Replacement Therapy; Leuprolide; Liver; Liver Neoplasms; Male; Mice; Mice, Transgenic; Orchiectomy; Organ Size; Proliferating Cell Nuclear Antigen; RNA, Messenger; Sex Characteristics; Testosterone; Transforming Growth Factor alpha

Transforming growth factor alpha (TGF-alpha) knockout mice have increased susceptibility to dextran sodium sulphate (DSS) induced colitis.. To substantiate the findings that TGF-alpha is a key mediator of colonic mucosal protection and/or repair mechanisms by evaluating the susceptibility of mice overexpressing TGF-alpha to DSS induced colitis.. TGF-alpha overexpression was induced in transgenic mice by ZnSO4 administration in drinking water (TG+). Three groups were used as controls: one transgenic group without ZnSO4 administration (TG-), and two non-transgenic littermate groups receiving ZnSO4 (Non-TG+) or only water (Non-TG-). Acute colitis was induced in all groups by administration of DSS (5%, w/v) in drinking water for six days and libitum.. About 35-39% of the entire colonic mucosa was destroyed in Non-TG-, Non-TG+, and TG- animals compared with 9% in TG+ mice. the crypt damage score was 18.7 (0.9), 18.2 (1.0), 18.9 (0.8), and 6.8 (1.5) (means (SEM)) in Non-TG-, Non-TG+, TG-, and TG+ mice respectively. Mucin and bromodeoxyuridine staining were markedly enhanced in colons of TG+ mice compared with controls, indicating increased mucosal protection and regeneration.. The significantly reduced susceptibility of mice overexpressing TGF-alpha to DSS further substantiates that endogenous TGF-alpha is a pivotal mediator of protection and/or healing mechanisms in the colon.

Topics: Acute Disease; Animals; Body Weight; Cell Division; Colitis; Colon; Dextran Sulfate; Disease Susceptibility; Intestinal Mucosa; Male; Mice; Mice, Transgenic; Radioimmunoassay; Statistics, Nonparametric; Transforming Growth Factor alpha; Zinc

We have previously demonstrated in short-term experiments that altered hepatocytes in liver acini draining the blood from intraportally transplanted pancreatic islets in streptozotocin-induced diabetic rats with mild persisting diabetes resemble those in preneoplastic foci of altered hepatocytes. We now present the results of long-term studies (up to 22 months) in this animal model. Glycogen-storing foci (which were the first parenchymal alteration observed some days after transplantation) persisted at least for 6 months, when the first mixed-cell foci and the first hepatocellular adenoma emerged. After 15 to 22 months, 86% of the animals exhibited at least one hepatocellular adenoma and four animals (19%) showed a hepatocellular carcinoma. The transplants were found in a close spatial relationship with the preneoplastic foci and the hepatocellular neoplasms. The mitotic indices, the 5-bromo-2'-desoxyuridine labeling indices and the apoptotic indices showed significant differences between the unaltered liver parenchyma, different types of preneoplastic foci, and hepatocellular neoplasms. The immunohistochemical expression of transforming growth factor-alpha increased during the stepwise development from glycogen-storing liver acini to hepatocellular carcinomas. Hepatocarcinogenesis in this new animal model is probably due to the hormonal and growth-stimulating effects of insulin secreted by the intraportally transplanted islets of Langerhans in diabetic rats.

Topics: Adenoma; Animals; Blood Glucose; Body Weight; Carcinoma, Hepatocellular; Case-Control Studies; Cause of Death; Cytoplasm; Diabetes Mellitus, Type 2; Endoplasmic Reticulum; Immunohistochemistry; Islets of Langerhans Transplantation; Liver Neoplasms, Experimental; Male; Microscopy, Electron; Neoplasm Staging; Precancerous Conditions; Rats; Rats, Inbred Lew; Streptozocin; Transforming Growth Factor alpha

The dose-effect relationships were analysed for several noncarcinogenic endpoints, such as immunological and biochemical responses at subchronic, low dose exposure of female C57BL/6 mice to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The animals were treated i.p. with TCDD according to the initial- and maintenance-dose principal for a period of 135 days. The initial doses were 1, 10 and 100 ng TCDD/kg, the weekly maintenance doses were 0.2, 2 and 20 ng TCDD/kg, respectively. At days 23, 79 and 135 of TCDD/kg, treatment 10 animals of each dose group were killed. As immunological parameters the number of thymocytes and the pattern of thymocyte subpopulations were determined. In liver, lung and thymus, mRNA expression of TGF-alpha, TGF-beta(1), TGF-beta(2), TGF-beta(3), TNF-alpha, IL-1 beta and different CYP1 isoforms (CYP1A1, CYP1A2, CYP1B1) was analysed. In the livers, activities of 7-ethoxyresorufin-O-deethylase (EROD) and 7-methoxyresorufin-O-demethylase (MROD) were measured. TCDD content in the liver was determined. The main results are summarized as follows: (1) The TCDD doses were not sufficient to elicit dose-dependent changes of pattern of thymocyte subpopulation. (2) TCDD failed to change the mRNA expression of TGF-alpha, TGF-beta and TNF-alpha, but led to an increase of IL-1 beta mRNA expression in liver, lung and thymus. The results show that the TCDD induced IL-1 beta mRNA increase is at least as sensitive a marker as the induction of CYP1A isoforms. (3) The expression of CYP1B1 mRNA remained unchanged at the doses tested, while CYP1A1 and CYP1A2 mRNA expression was dose-dependently enhanced. EROD and MROD activities in the liver paralleled the increases of CYP1A1 and CYP1A2 mRNA expression. (4) Regression analysis of the data showed that most of the parameters tested fit a linear model. (5) From the data, a benchmark dose for EROD/MROD activities in the livers of female C57BL/6 mice of about 0.03 ng TCDD/kg per day was calculated.

Topics: Animals; Aryl Hydrocarbon Hydroxylases; Body Weight; Cell Count; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1A2; Cytochrome P-450 CYP1B1; Cytochrome P-450 Enzyme System; Dose-Response Relationship, Drug; Female; Gene Expression Regulation, Enzymologic; Injections, Intraperitoneal; Interleukin-1; Liver; Lung; Mice; Mice, Inbred C57BL; Organ Size; Polychlorinated Dibenzodioxins; Polymerase Chain Reaction; Regression Analysis; RNA, Messenger; Thymus Gland; Transforming Growth Factor alpha; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Using immunohistochemistry, Northern blotting and a semi-quantitative PCR technique, epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha) and epidermal growth factor receptor (EGFR) expression were studied in the pancreas of N-nitrosobis(2-oxopropyl)-amine (BOP)-treated hamsters. After initiation pancreatic carcinogenesis was modulated by a high fat diet or by injections with the cholecystokinin analogue caerulein. Autopsies were performed 6 and 12 months after the last injection with BOP. Immunohistochemistry revealed a weak expression of TGF-alpha in nomal acinar cells and a stronger expression in ductular and centro-acinar cells. Over-expression of TGF-alpha was observed in advanced putative preneoplastic lesions (classified as borderline lesions) and in ductular adenocarcinomas. EGFR immunoreactivity was present only in ductular adenocarcinomas. EGF peptide expression was observed both in acinar and ductular normal and tumorous cells and the level of expression did not change significantly during carcinogenesis. Moreover, the post-initiation treatments did not cause differences in EGF, TGF-alpha or EGFR peptide or mRNA levels, except for a significantly lower expression of TGF-alpha mRNA in hamsters fed a high fat diet when compared with those fed a low fat diet. TGF-alpha mRNA levels increased, whereas EGF mRNA levels decreased significantly in total pancreatic homogenates of BOP-treated hamsters in comparison with untreated controls. Also, in ductular adenocarcinomas TGF-alpha and EGFR (but not EGF) mRNA levels were significantly higher than in normal pancreatic homogenates. In pancreatic homogenates obtained 6 months after the last BOP injection, these differences were less pronounced in comparison with those obtained after 12 months. The present results indicate that TGF-alpha (but not EGF) might act in a paracrine or autocrine manner in pancreatic tumours in BOP-treated hamsters via simultaneously expressed EGFR. However, TGF-alpha, EGF and EGFR do not seem to be involved in the modulating effects of a high fat diet or caerulein treatment on pancreatic carcinogenesis in BOP-treated hamsters.

Topics: Adenocarcinoma; Animals; Blotting, Northern; Body Weight; Carcinogens; Cricetinae; Epidermal Growth Factor; ErbB Receptors; Immunohistochemistry; Mesocricetus; Nitrosamines; Organ Size; Pancreas; Pancreatic Neoplasms; Polymerase Chain Reaction; Transforming Growth Factor alpha

As a possible step in examining the difference between pathological models and most popular and 'normal' models, the mammary gland and some parameters were compared in SHN mice, a high mammary tumor strain, and ICR mice. SHN was lower than ICR in almost all urinary component levels as indicators of general metabolic activity in both the female and the male, and glucose tolerance in the female. Body weight and several organ weights including liver and kidneys were lower in SHN than in ICR. Normal and preneoplastic mammary gland growth and TGF alpha mRNA expression in the glands of the female were much higher in SHN than in ICR. These findings stress the importance of having a right knowledge of the parameters of 'normal' animals, especially for researchers using pathological models.

Topics: Animals; Blood Glucose; Body Weight; Female; Glucose Tolerance Test; Kidney; Liver; Magnetic Resonance Spectroscopy; Male; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mice; Mice, Inbred ICR; Mice, Mutant Strains; Organ Size; Prolactin; RNA, Messenger; Transforming Growth Factor alpha

Five phenolic compounds, namely caffeic acid, sesamol, hydroquinone, catechol, and 4-methoxyphenol, were fed to groups of 30 male F344 rats at dietary levels of 2, 2, 0.3, 0.8, and 2%, respectively, for 2 years. Retardation of body weight and elevated relative liver weights were noted for all groups. Formalin-fixed and paraffin-embedded liver tissues from rats killed terminally were cut and stained for glutathione S-transferase placental form (GST-P) and tumor growth factor alpha (TGF alpha) immunohistochemically. Numbers and areas of GST-P-positive (GST-P+) foci per unit area of liver section were measured, and the respective treated/control proportional values were calculated to be 58 and 57% for caffeic acid. 58 and 54% for sesamol, 71 and 71% for hydroquinone. 58 and 133% for catechol, and 49 and 39% for 4-methoxyphenol. These data were comparable with results obtained with medium-term liver bioassays (Ito test). However, no intergroup differences were detected with regard to quantitative findings for TGF alpha foci, which were relatively rare. Long-term inhibitory effects of phenolic compounds on liver carcinogenesis, predicted from the Ito test, were thus confirmed in the present feeding studies using quantitative analysis of immunohistochemically demonstrable GST-P+ foci as end point marker lesions.

Topics: Animals; Anticarcinogenic Agents; Body Weight; Drug Administration Schedule; Glutathione Transferase; Immunohistochemistry; Liver; Liver Neoplasms, Experimental; Male; Organ Size; Phenols; Precancerous Conditions; Rats; Rats, Inbred F344; Transforming Growth Factor alpha

Expression of transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) was studied in normal pancreatic tissue and in (pre)neoplastic pancreatic lesions of azaserine-treated rats. They were given either a low fat, high fiber (low caloric) diet, to inhibit carcinogenesis, or a low fat diet combined with injections of the cholecystokinin analog caerulein to enhance carcinogenesis. The control groups, maintained on a low fat diet, were injected with azaserine or were not treated at all. Autopsy was performed at 6 and 15 months after the last azaserine injection. After both 6 and 15 months immunohistochemistry revealed a weak expression of EGF and TGF-alpha peptides in the acinar cells, and a stronger expression in the ductular and centroacinar cells. TGF-alpha peptide expression was reduced in both putative preneoplastic and neoplastic acinar cell lesions, but no differences in EGF peptide expression were observed between the various stages of exocrine pancreatic carcinogenesis. After 16 months an increase in TGF-alpha mRNA due to treatment with azaserine was detected by semi-quantitative PCR in total pancreatic homogenates, whereas EGF mRNA expression had decreased. TGF-alpha mRNA levels in macroscopically isolated tumors were significantly lower, but EGF mRNA levels were significantly higher, than in total pancreatic homogenates from azaserine-treated rats. Furthermore, EGF and TGF-alpha mRNA levels in isolated tumors did not differ significantly from mRNA levels in non-carcinogen-treated rats. Neither with immunohistochemistry nor with PCR were differences in EGF or TGF-alpha expression observed due to either inhibition or stimulation of carcinogenesis. It is concluded that putative preneoplastic acinar cell lesions induced in rat pancreas by azaserine may develop into acinar adenocarcinomas independently of TGF-alpha and EGF. The results suggest involvement of these growth factors at the early stage of the carcinogenic process, during the initiation of normal acinar cells into putative preneoplastic cells. However, modulation of azaserine-induced pancreatic carcinogenesis by cholecystokinin or a low fat, high fiber (caloric restricted) diet appeared not to be regulated by EGF or TGF-alpha.

Topics: Animals; Azaserine; Base Sequence; Body Weight; Carcinogens; Ceruletide; Cocarcinogenesis; Diet, Fat-Restricted; Dietary Fiber; Drug Synergism; Energy Intake; Epidermal Growth Factor; Immunohistochemistry; Male; Molecular Sequence Data; Organ Size; Pancreas; Pancreatic Neoplasms; Polymerase Chain Reaction; Rats; Rats, Wistar; RNA, Messenger; Transforming Growth Factor alpha

Hepatocyte growth factor (HGF) and transforming growth factor alpha (TGF alpha) are potent mitogens for mature hepatocytes in primary culture (Nakamura, et al. 1984, Mead et al., 1989). However, these cytokines have completely different effects on tumor cell growth (Jhappan et al., 1990, Shiota et al, 1992). To clarify dual effects of these cytokines in liver, we developed double transgenic mice of HGF and TGF alpha using albumin promoter-HGF cDNA transgenic mice (AlbHGF) and metallothionein promoter-TGF alpha transgenic mice (MthTGF alpha). Double transgenic mice were examined on DNA synthesis, c-myc mRNA and occurrence of hepatocelular carcinoma (HCC). Higher labeling indices using BrDU were observed, in sequence, in AlbHGF mice, AlbHGF/MthTGF alpha, MthTGF alpha and wild type mice. Hepatic expression of c-myc mRNA in AlbHGF mice was elevated, compared to that in AlbHGF/MthTGF alpha or MthTGF alpha mice. After long-term observation, MthTGF alpha mice developed HCC in 6/10 (60%), whereas AlbHGF/MthTGF alpha mice developed HCC in 3/9 (33%). These data suggest that HGF is the potent mitogen, stimulating DNA synthesis and up-regulating c-myc mRNA. In addition, HGF may excert some inhibitory effect on occurrence of HCC by TGF alpha.

Topics: Animals; Body Weight; Bromodeoxyuridine; Carcinoma, Hepatocellular; DNA; Hepatocyte Growth Factor; Mice; Mice, Transgenic; Organ Size; Proto-Oncogene Proteins c-myc; RNA, Messenger; Transforming Growth Factor alpha

In this study we tested the effects of repeated administrations of Epidermal Growth Factor (EGF) and Transforming Growth Factor-alpha (TGF-alpha) on mouse pups' neurobehavioral development. Each subject was injected subcutaneously with either EGF or TGF-alpha on postnatal days 2, 4, 6, 8, and 10. Pups treated with these two peptides showed accelerated eyelid opening and eruption of the lower incisors when compared to Cytochrome c-injected control littermates. EGF, but not TGF-alpha, resulted in a slight body growth retardation. When scored for a number of neurobehavioral parameters, EGF pups showed a delayed appearance of the righting reflex. Also, EGF-treated pups exhibited greater ultrasonic vocalization calling rates than controls when tested on postnatal day 7. Overall, TGF-alpha administration resulted in minor effects, when compared with EGF treatment, probably as a result of the lower dose administered (EGF: 3.5 mg/kg vs TGF-alpha: 1 mg/kg). TGF-alpha affected pups' eyelid opening and incisor eruption, similarly to EGF, but seemed to exert an opposite effect on some neurobehavioral scores, in line with what was already reported for Nerve Growth Factor (NGF) (Calamandrei and Alleva, 1989). These results confirm the role played by polypeptide growth factors on mammalian physical and neurobehavioral development and suggest that TGF-alpha might affect mouse brain development in a similar fashion as NGF.

Topics: Animals; Behavior, Animal; Body Weight; Cytochrome c Group; Developmental Biology; Epidermal Growth Factor; Mice; Neurons; Transforming Growth Factor alpha

The purpose of the present study was to evaluate the therapeutic efficacy of low-dose interleukin-2 (IL-2) alone or together with antibody against transforming growth factor-beta (TGF-beta) in a Herpes simplex virus Type 2-transformed (H238) fibrosarcoma model. BALB/c mice were inoculated subcutaneously (s.c.) with 5 x 10(5) H238 tumor cells in one or both hind thighs and treated with IL-2, anti-TGF-beta, or a combination of both agents. Nontreated tumor-bearing and normal animals served as controls. In the appropriate treatment groups, each mouse was given a total of 10(5) international units (i.u.) of IL-2 s.c. at one tumor implantation site and/or 1 microgram of anti-TGF-beta intraperitoneally (i.p.) over a period of 5 days beginning on the day of tumor cell implantation. No toxicity was noted during treatment. The slowest tumor growth was observed in mice with single tumors when treated with IL-2 or anti-TGF-beta alone, whereas combination treatment resulted in growth similar to that of untreated controls. However, in animals with two tumors, the tumor injected with IL-2 grew more rapidly than the untreated one. Spleen cell responsiveness to mitogenic stimulation was generally depressed in tumor-bearing mice compared to normal controls, but some differences were noted with treatment. In contrast, tumor presence induced striking splenomegaly and enhanced the chemiluminescent oxidative burst of phagocytic cells in the spleen. In the groups with a single tumor, plasma TGF-beta levels were similar to those of nontumor-bearing controls, however the concentrations were decreased in the animals with two tumors. These results show that IL-2 or anti-TGF-beta can slow progression of H238 tumors under certain conditions. However, combination of the two modalities proved to be of no benefit.

Topics: Animals; Antibodies; Body Weight; Cell Size; Cell Transplantation; Fibrosarcoma; Immunotherapy; Interleukin-2; Luminescent Measurements; Male; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Organ Size; Respiratory Burst; Spleen; Transforming Growth Factor alpha; Tumor Cells, Cultured

Multiparous SHN mice with spontaneous mammary tumors (5-10 mm in size) were given water extract of Guan-mu-tong (Gmt; Caulis aristolochiae manshuriensis) (0.5%) ad libitum as drinking water for 10 days. This treatment retarded significantly the growth of mammary tumors compared with the controls. By contrast, normal mammary gland growth, histology of adrenals and ovaries, and body weight were affected little by the Gmt treatment. Gmt appears to be the first agent inhibiting the growth of spontaneous mouse mammary tumors of palpable size by per os treatment.

Topics: Animals; Antineoplastic Agents, Phytogenic; Body Weight; Drugs, Chinese Herbal; Endocrine Glands; Female; Mammary Neoplasms, Animal; Mice; Transforming Growth Factor alpha

The carcinogenic and tumor-promoting effects of human transforming growth factor alpha (TGF-alpha) overexpression were examined in a two-stage chemical carcinogenesis protocol using TGF-alpha transgenic mouse line MT42. Male MT42 and CD-1 mice received a single i.p. injection of 5 mg N-nitrosodiethylamine (DEN)/kg body wt at 15 days of age, and were placed on a diet containing 0.05% of phenobarbital (PB) from 4 weeks of age for 35 weeks. DEN-, PB-treated and saline-injected animals in each strain were used as controls. A total of three sequential sacrifices (at 10, 23 and 37 experimental weeks) was performed. Hepatocellular carcinomas (HCCs) developed earlier at high incidence (100%) after 23 experimental weeks in MT42 mice receiving DEN/PB, while CD-1 mice had a 40% incidence of HCCs only after week 37. HCCs also developed in the DEN-initiated MT42 mice at 80% incidence after week 23, but no HCCs were observed in the DEN-initiated CD-1 mice. PB induced preneoplastic foci (67%), adenomas (33%) and HCCs (33%) after 37 weeks in MT42 mice, but no lesions were found in CD-1 mice. Thus, the carcinogenic response to DEN and/or PB was accelerated in the MT42 transgenic mice. Furthermore, PB promotion was observed from week 10 in MT42 mice and week 23 in CD-1 mice. Thus, the promoting effect of PB was also accelerated in the MT42 transgenic mice. Proliferating cell nuclear antigen (PCNA) labeling indices of hepatocellular foci and adenomas in DEN- or DEN/PB-treated MT42 mice were significantly higher than those of CD-1 mice. TGF-alpha expression determined by immunohistochemistry revealed higher levels in these lesions than in hepatocytes of surrounding parenchyma of MT42 transgenic mice. In conclusion, TGF-alpha transgenic mice clearly demonstrated enhanced sensitivity to the development of hepatocellular carcinoma in the DEN initiation and PB promotion regime, possibly through a mechanism of increased hepatocyte proliferation in precancerous lesions (foci and adenomas), driven by high expression of the mitogen TGF-alpha in these lesions.

Topics: Animals; Body Weight; Cell Division; Cocarcinogenesis; Diethylnitrosamine; Gene Expression; Immunohistochemistry; Liver Neoplasms, Experimental; Male; Mice; Mice, Transgenic; Phenobarbital; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Transforming Growth Factor alpha

Transforming growth factor-alpha (TGF-alpha) expression is associated with hepatocyte DNA replication both in vivo and in culture. Our previous work using TGF-alpha transgenic mice showed that constitutive overexpression of this growth factor in the liver causes hepatic tumors in 75 to 80% of the animals at 12 to 15 months of age. To understand the cellular events by which TGF-alpha overexpression leads to abnormal liver growth, we examined hepatocyte proliferative activity in young and old TGF-alpha transgenic mice and hepatocyte ploidy in normal, dysplastic, and neoplastic livers of these animals. At 4 weeks of age, transgenic mice had higher liver weights and liver weight/body weight ratios than non-transgenic mice of the same age and hepatocyte proliferative activity, measured by 3H-thymidine incorporation after 3- and 7-day infusion, proliferating cell nuclear antigen staining, and mitotic index determination, was 2 to 3 times higher than in controls. In both transgenic and non-transgenic mice hepatocyte proliferation declined with age but the decrease was much more pronounced in control animals, so that at 8 months of age, hepatocyte replication was 8 to 10 times higher in transgenic animals. Surprisingly, however, transgenic and non-transgenic mice at this age had similar liver weight/body weight ratios. Labeling studies done in 3-month-old animals revealed that hepatocyte turnover was much faster in transgenic than in control animals, suggesting that a homeostatic compensatory mechanism involving cell death tended to restore normal liver weight/body weight ratios in older transgenic mice. Ploidy analyses showed that at 4 weeks of age transgenic mice had a higher proportion of diploid and tetraploid hepatocytes and that the hepatocellular tumors which developed in TGF-alpha transgenic mice at 13 months of age contained a higher fraction of diploid hepatocytes than that present in adjacent tissue or in dysplastic livers. The results demonstrate that constitutive overexpression of TGF-alpha causes increased hepatocyte proliferation and liver enlargement in young animals and is associated with a delay in the establishment of hepatic polyploidy. These findings as well as the response of transgenic mice to partial hepatectomy show that constitutive overexpression of TGF-alpha initially caused increased but regulated hepatocyte proliferation which in older animals was compensated in part by a faster cell turnover. At 8 to 10 months of age, proliferative

Topics: Aging; Animals; Body Weight; Carcinoma, Hepatocellular; Cell Cycle; Cell Division; Liver; Liver Neoplasms; Liver Regeneration; Mice; Mice, Transgenic; Organ Size; Ploidies; Reference Values; Transforming Growth Factor alpha

Pancreatic cancer cell lines overexpress epidermal growth factor (EGF) receptors and also have the capacity to produce transforming growth factor alpha (TGF alpha), the alternate agonist of the EGF receptor. The purpose of this study was to determine if TGF alpha had a trophic effect on the growth of pancreatic cancer in vivo. Syrian golden hamsters were inoculated with 50,000 H2T hamster ductal pancreatic cancer cells. The hamsters were then randomised to three equal groups: the groups received either saline (control), EGF, or TGF alpha, each by intraperitoneal injection, three times a day. Treatment continued for seven weeks, and each week the hamsters were weighed and tumour areas were measured. The hamsters were then killed, and the tumours were excised, weighed, and extracted for assay of DNA content as a measure of cellularity. From week four onwards both EGF and TGF alpha significantly stimulated tumour growth. Although tumour weights were not significantly different, tumour DNA content had nearly doubled after exposure to both EGF and TGF alpha. It is concluded that like EGF, TGF alpha can stimulate pancreatic cancer growth in vivo, and this may in part explain the aggressive nature of these cancers in clinical practice.

Topics: Animals; Body Weight; Cricetinae; DNA, Neoplasm; Epidermal Growth Factor; Injections, Intraperitoneal; Mesocricetus; Pancreatic Neoplasms; Random Allocation; Transforming Growth Factor alpha; Tumor Cells, Cultured

Transgenic mice overexpressing transforming growth factor alpha (TGF-alpha) under control of the metallothionein promoter had, on average, 20% reductions in body and carcass weights compared to nontransgenic littermates. This loss resulted from significant decreases in the comparative weights of bone, muscle, and especially fat. Transgenic epididymal fat pads were reduced by 40-80%, and total body fat content by 50%, relative to control animals. Distal hindlimb muscle weights were 20% below normal, and other skeletal muscles were visibly smaller in size. Weight reductions were accompanied by decreases in the cellularity of transgenic fat pads and muscles and by decreases in the number and area of striated muscle fibers. These findings were not obviously attributable to differences in metabolic rates since transgenic and control mice displayed similar levels of energy expenditure per unit lean body mass. The effects of TGF-alpha on the development of these tissues could be mimicked in culture for fat but not muscle. Thus, TGF-alpha did not inhibit the differentiation of the mouse skeletal myoblast cell line C2C12 as evidenced by the expression of muscle-specific actin and fusion to form multinucleated myotubes. However, TGF-alpha repressed the differentiation of the preadipocyte cell line 3T3-F442A in a dose-dependent and reversible manner as judged by morphological conversion and diminished expression of mRNAs encoding the adipocyte-specific markers adipsin and glycerophosphate dehydrogenase. This repression, which occurred without marked stimulation of proliferation, was incomplete even in the presence of high concentrations of growth factor. Despite its effects on adipose development, introduction of the metallothionein-TGF-alpha transgene into the ob/ob genetic background did not suppress the marked obesity characteristic of this mutation. Finally, endogenous TGF-alpha epidermal growth factor receptor mRNAs were detected in normal adipose tissue, suggesting that regulation of adipogenesis by this growth factor may be physiological.

Topics: Adipose Tissue; Animals; Body Weight; Cell Differentiation; Cells, Cultured; Male; Mesoderm; Mice; Mice, Transgenic; Muscle Development; Transforming Growth Factor alpha

Psychosocial factors are thought to influence risk and survival from cancer. We have previously studied specific behaviours in transgenic male CD-1 MT42 mice, which overexpress the gene encoding human transforming growth factor alpha (TGF alpha) in multiple tissues, and which develop a high incidence of spontaneous hepatocellular carcinoma. The male TGF alpha mice spent a lengthened time immobile in the swim test, were highly aggressive, had increased plasma levels of 17 beta-estradiol (E2), and reduced natural killer (NK) cell activity. The female transgenic MT42 TGF alpha mice do not develop an increased rate of tumours at any site. We hypothesised that if the alterations in male TGF alpha mice are associated with their development of hepatocellular carcinomas, female TGF alpha should not show these alterations. The data in the present study indicate that female TGF alpha mice display shortened immobility in the swim test, suggesting an improved ability to cope with stress, and appear less aggressive in the resident-intruder test than non-transgenic female CD-1 mice. The female TGF alpha mice also exhibit a 3-fold increase in the plasma levels of E2, and a 3-fold increase in NK cell activity. These findings suggest that the elevated expression of TGF alpha in the transgenic mice is associated with gender-specific behavioural alterations, and the development of spontaneous hepatocellular tumours in the males. Furthermore, TGF alpha alters hormonal and immune parameters similarly in both sexes. It remains to be determined whether the development of hepatocarcinoma in the male TGF alpha animals is associated with an impaired ability to cope with stress and elevated aggressive tendencies and/or whether manipulations leading to an impaired ability to cope with stress will promote tumourigenesis in female TGF alpha mice.

Topics: Aggression; Animals; Behavior, Animal; Body Weight; Depression; Estradiol; Estrus; Female; Killer Cells, Natural; Liver; Male; Mice; Mice, Transgenic; Pancreas; Sex Factors; Stress, Physiological; Testosterone; Transforming Growth Factor alpha

The expression of transforming growth factor alpha (TGF alpha) is widely distributed throughout many normal and neoplastic tissues, but its physiological significance remains unclear. We have utilized male transgenic mice overexpressing the gene encoding human TGF alpha in multiple tissues to further identify those functions which are influenced by this protein. Male TGF alpha mice develop hepatocellular carcinoma at the age of 10-15 months. At the age of 2-3 months these mice, compared to age matched CD-1 controls, spent significantly longer times immobile in Porsolt's swim test, a model of stress and depressive behavior, and exhibiting aggressive behavior in the resident-intruder test. In contrast, the transgenic TGF alpha mice did not differ from the controls in either the plusmaze test of anxiety, or in their voluntary alcohol intake. Significantly, the TGF alpha mice exhibited a 25% lower Natural Killer (NK) cell activity and a four-fold increase in the plasma levels of 17-beta-estradiol (E2) than the controls. No significant changes in plasma testosterone or corticosterone levels were noted. The results indicate that transgenic male mice overexpressing TGF alpha exhibit behaviors characteristic of both an impaired ability to cope with stress and an increased aggressivity. The TGF alpha mice also show reduced NK cell activity and increased plasma estradiol concentrations. The present data suggest that TGF alpha may be important in influencing behavioral, immunological and hormonal systems prior to the onset of tumors. It remains to be determined whether hepatocarcinoma is associated with the direct proliferative and transforming effects of TGF alpha and/or indirect effects mediated through immune, hormonal and behavioral mechanisms.

Topics: Aggression; Alcohol Drinking; Animals; Behavior, Animal; Body Weight; Corticosterone; Killer Cells, Natural; Male; Mice; Mice, Transgenic; Steroids; Transforming Growth Factor alpha

We have previously demonstrated that BDS.1 cells are a minimal deviation rat hepatoma cell line that is hypersensitive to the anti-proliferative effects of glucocorticoids in vitro. When transplanted into athymic mice, exposure to dexamethasone reduced the initial growth rate and increased the latency time before detection of palpable BDS.1-derived tumors but did not affect the maximal growth rate, size and histology of the tumor. After collagenase dissociation, the in vitro growth of BDS.1-derived tumor cells was fully suppressed by dexamethasone. Exposure to insulin prevented the glucocorticoid inhibition of anchorage-independent growth of BDS.1 cell colonies in vitro and may therefore be one of the systemic factors that masks the long term in vivo growth response of glucocorticoids.

Topics: Animals; Body Weight; Carcinoma, Hepatocellular; Cell Adhesion; Cell Division; Cell Line; Dexamethasone; Dose-Response Relationship, Drug; Drug Antagonism; Insulin; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Liver Neoplasms; Mammary Neoplasms, Animal; Mice; Mice, Nude; Neoplasm Transplantation; Neoplasms, Experimental; Platelet-Derived Growth Factor; Rats; Transforming Growth Factor alpha; Tumor Cells, Cultured