transforming-growth-factor-alpha and Precancerous-Conditions

Hepatocarcinogenesis is a slow process during which genomic changes progressively alter the hepatocellular phenotype to produce cellular intermediates that evolve into hepatocellular carcinoma. During the long preneoplastic stage, in which the liver is often the site of chronic hepatitis, cirrhosis, or both, hepatocyte cycling is accelerated by upregulation of mitogenic pathways, in part through epigenetic mechanisms. This leads to the production of monoclonal populations of aberrant and dysplastic hepatocytes that have telomere erosion and telomerase re-expression, sometimes microsatellite instability, and occasionally structural aberrations in genes and chromosomes. Development of dysplastic hepatocytes in foci and nodules and emergence of hepatocellular carcinoma are associated with the accumulation of irreversible structural alterations in genes and chromosomes, but the genomic basis of the malignant phenotype is heterogeneous. The malignant hepatocyte phenotype may be produced by the disruption of a number of genes that function in different regulatory pathways, producing several molecular variants of hepatocellular carcinoma. New strategies should enable these variants to be characterized.

Topics: Carcinoma, Hepatocellular; Chromosome Aberrations; DNA Methylation; Gene Expression Regulation, Neoplastic; Genetic Heterogeneity; Humans; Insulin-Like Growth Factor II; Liver Neoplasms; Precancerous Conditions; Transforming Growth Factor alpha

Pancreatic cancer is a devastating disease with a fatal prognosis due to late diagnosis and resistance to radiation and chemotherapy. The average survival after diagnosis is still 3 to 8 months. In the last few years genetic alterations in cancer-causing genes have been identified in tumors and putative premalignant lesions using microdissection techniques. However, the functional consequence of these genetic alterations for pancreatic growth and differentiation is unknown. TGF alpha overexpressed in the pancreas causes the development of tubular structures and fibrosis. Mice older than one year develop ductal pancreatic cancer. Crossbreeding these mice with p53 knockout mice dramatically accelerated tumor development. Moreover, tumors developing in these mice show frequently biallelic deletion of the Ink4a locus or LOH of SMAD4. These mice represent the first model of pancreatic adenocarcinomas with genetic alterations as well as growth characteristics similar to the human disease.

Topics: Animals; Cell Cycle; Genes, p53; Humans; Mice; Mice, Transgenic; Pancreatic Neoplasms; Precancerous Conditions; Transforming Growth Factor alpha

Barrett esophagus is a premalignant condition that may progress to adenocarcinoma. The risk of developing cancer has been estimated to be approximately 1 in 250 patient-years of observation; however, there appear to be subsets of patients at much higher risk. Risk stratification has previously been determined by histological identification of dysplasia. Several new biomarkers are being tested to help clinicians better determine the risk of cancer development. Although none of these biomarkers has been proven in a prospective study to predict the onset of cancer, they have been correlated with cancer development. Most of these are factors that have been associated with cancer development in other organs. These include assessment of cell proliferation, expression of cyclooxygenase 2, growth factors and oncogenes, secretory factors, cell cycle proteins, adhesion molecules, and aneuploidy and other genetic abnormalities. In addition to their role as potential cancer biomarkers, these factors have increasingly been reported as surrogate markers to monitor the effectiveness of conservative treatments for Barrett esophagus. In this article, biological markers are reviewed for their relevance in Barrett esophagus. Although most biological markers need to be evaluated further and, for most, prospective follow-up studies are lacking, at present abnormal ploidy status, P16 and P53 gene abnormalities, or allelic losses are the most extensively documented.

Topics: Barrett Esophagus; Biomarkers; Cyclooxygenase 2; Epidermal Growth Factor; ErbB Receptors; Esophageal Neoplasms; Female; Humans; Immunohistochemistry; Isoenzymes; Male; Membrane Proteins; Ornithine Decarboxylase; Precancerous Conditions; Prostaglandin-Endoperoxide Synthases; Sensitivity and Specificity; Transforming Growth Factor alpha

Although transgenic mouse models for breast cancer have frequently been reported in the literature, transgenic rat models have not been described. We have generated transgenic rats overexpressing the human transforming growth factor alpha (TGF alpha) and c-erbB-2 genes in the mammary gland under the control of the mouse mammary tumour virus (MMTV) long terminal repeat promoter, and have analysed multiple lines of these rats to the second (F2) generation. Female MMTV/TGF alpha rats frequently develop severe hyperplasias during pregnancy, and a variety of tumours of long latency. The mammary glands of MMTV/TGF alpha rats fail to involute fully after the completion of lactation. Expression of the TGF alpha transgene is highest in the hyperplasias. MMTV/c-erbB-2 female rats develop a spectrum of benign and malignant lesions, including ductal carcinoma in situ and carcinomas. Expression of the c-erbB-2 transgene is found in benign tumours such as fibroadenomas, but is highest in the carcinomas. These animals model a spectrum of lesions found in human breasts and suggest that TGF alpha overexpression can act at a relatively early stage in the pathogenesis of breast cancer in the rat, resulting in a predominantly hyperplastic response, whereas overexpression of c-erbB-2 plays a role in the induction of various benign lesions and more advanced breast carcinomas.

Topics: Animals; Female; Humans; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Precancerous Conditions; Pregnancy; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Receptor, ErbB-2; Repetitive Sequences, Nucleic Acid; Transforming Growth Factor alpha

Topics: Animals; Carcinogens; Cells, Cultured; Disease Progression; Fibroblast Growth Factor 10; Fibroblast Growth Factor 7; Fibroblast Growth Factors; Growth Substances; Mice; Precancerous Conditions; Skin Neoplasms; Transforming Growth Factor alpha; Transforming Growth Factor beta

The mouse skin model of multistage carcinogenesis continues to serve as a major in vivo model for studying the sequential and stepwise evolution of the cancer process by chemical and physical carcinogens. The initiation stage of mouse skin carcinogenesis involves genetic damage in the form of DNA adducts or initiator-induced DNA base changes. These changes ultimately lead to mutations in critical target genes of epidermal stem cells. The rasHa gene, and to a limited extent the N-ras gene, have been identified as target genes for certain tumor initiators in this model system (reviewed in DiGiovanni 1992). The promotion stage of mouse skin carcinogenesis involves the production and maintenance of a chronic state of hyperplasia and cell proliferation and ultimately the selective clonal expansion of initiated cells. The hallmark of all tumor promoters that have been adequately tested is their ability to induce a potentiated hyperplasia after several treatments that is greater than that observed after a single application. Tumor promoters produce many effects when applied topically to mouse skin. Many of the effects that occur after a single application of phorbol esters such as TPA appear to be mediated by its interaction with PKC (Nishizuka 1989). An important question is whether the activation of PKC per se is responsible for tumor promotion by TPA. Because repetitive treatments with TPA lead to a sustained loss of PKC, it is possible that other effects not mediated by PKC but produced by phorbol esters and related compounds may play an important role in the production and maintenance of chronic hyperplasia and cell proliferation in the skin and for skin tumor promotion. More attention should be placed on studying the promoting actions of other compounds outside of the most commonly studied phorbol esters. Investigations of some of these compounds already have and will continue to provide important clues regarding possible common pathways shared by diverse promoting agents. One such pathway may involve the EGFr and its ligand TGF alpha. As discussed in this review, it is now evident that many different types of promoting agents increase production of TGF alpha (Ellem et al. 1988, Pittelkow et al. 1989, Choi et al. 1991, Imamoto et al. 1991, J. DiGiovanni unpublished studies). Although many tumor promoters initially decrease the binding of 125I-EGF to EGFr in specific cell types, including mouse epidermal cells, the long-term effects of tumor promoters, espe

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Carcinogens; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Cocarcinogenesis; Disease Progression; ErbB Receptors; Mice; Models, Biological; Papilloma; Phorbol Esters; Precancerous Conditions; Skin Neoplasms; Transforming Growth Factor alpha

Topics: DNA, Viral; Gene Rearrangement; Genes, Tumor Suppressor; Hepatitis B; Insulin-Like Growth Factor II; Liver Neoplasms; Precancerous Conditions; Proto-Oncogenes; Transforming Growth Factor alpha; Transforming Growth Factor beta

Topics: beta-Defensins; Biomarkers; Carcinoma, Squamous Cell; Epidermal Growth Factor; ErbB Receptors; Erythroplasia; Humans; Leukoplakia, Oral; Mouth Neoplasms; Precancerous Conditions; Prognosis; Transforming Growth Factor alpha; Tumor Suppressor Protein p53

The chronic ethanol intake influence on the gluthatione S-transferase (GST-P) and transforming growth factor alpha (TGF-alpha) expression in remodeling/persistent preneoplastic lesions (PNLs) was evaluated in the resistant hepatocyte model. Male Wistar rats were allocated into five groups: G1, non-treated, fed water and chow ad libitum; G2, non-treated and pair-fed chow (restricted to match that of G3 group) and a maltodextrin (MD) solution in tap water (matched ethanol-derived calories); G3, fed 5% ethanol in drinking water and chow ad libitum; G4, diethylnitrosamine (DEN, 200 mg/kg, body weight) plus 200 parts per million of 2-acetylaminofluorene (2-AAF) for 3 weeks and pair-fed chow (restricted to match that of G5 group) and an MD solution in tap water (matched ethanol-derived calories); G5, DEN/2-AAF treatment, fed ethanol 5% and chow ad libitum. All animals were subjected to 70% partial hepatectomy at week 3 and sacrificed at weeks 12 or 22, respectively. Liver samples were collected for histological analysis or immunohistochemical expression of GST-P, TGF-alpha and proliferating cell nuclear antigen or zymography for matrix metalloproteinases-2 and -9. At the end of ethanol treatment, there was a significant increase in the percentage of liver area occupied by persistent GST-P-positive PNLs, the number of TGF-alpha-positive PNLs and the development of liver tumors in ethanol-fed and DEN/2-AAF-treated groups (G5 versus G4, P < 0.001). In addition, ethanol feeding led to a significant increase in cell proliferation mainly in remodeling and persistent PNLs with immunoreactivity for TGF-alpha at week 22 (P < 0.001). Gelatinase activities were not altered by ethanol treatment. The results demonstrated that ethanol enhances the selective growth of PNL with double expression of TGF-alpha and GST-P markers.

Topics: Animals; Apoptosis; Ethanol; Glutathione Transferase; Immunohistochemistry; Liver Neoplasms, Experimental; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Precancerous Conditions; Rats; Rats, Wistar; Transforming Growth Factor alpha

Growth factors and hormones are responsible for development of the mammary gland and can contribute to mammary carcinogenesis. The transforming growth factors (TGF) alpha and beta1 demonstrate opposing effects on the mammary epithelium. TGFalpha is a mitogen and survival factor for mammary secretory cells and is often upregulated in cancer, while TGFbeta1 may act as a growth suppressor and has been shown to inhibit alveolar development and lactogenesis. To examine the contradistinct effects of TGFalpha and TGFbeta1 on normal mammary epithelium, we crossed MT-TGFalpha mice with WAP-TGFbeta1 transgenic mice. The newly generated bitransgenic mice failed to nurse their pups and were resistant to mammary tumorigenesis (0% at 12 months of age), compared to single transgenic MT-TGFalpha in which the majority (65% at 12 months of age) of the mice developed hyperplastic alveolar mammary lesions. Transplantation studies showed that bitransgenic tissue was highly resistant to tumor formation even after multiple pregnancies. WAP-TGFbeta1 mammary transplants often failed to grow and fully fill cleared mammary fat pads upon transplantation. This repression of growth was completely reversed in the bitransgenic implants, which grew as well as normal epithelium upon transplantation. In addition, TGF and bitransgenic TGFalpha/TGFbeta1 mice had reduced rates of apoptosis during involution as compared to wild type and TGFbeta1. These data demonstrate that TGFbeta1 and TGFalpha exhibit opposing effects upon the proliferation and survival of mammary epithelium when expressed alone but when expressed together result in reciprocally suppressive effects upon one another in the context of mammary development and tumorigenesis.

Topics: Animals; Apoptosis; Cell Survival; Epithelium; Female; Genotype; Humans; Immunohistochemistry; Male; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mice; Mice, Inbred Strains; Mice, Transgenic; Phenotype; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Transforming Growth Factor alpha; Transforming Growth Factor beta1

A role of the epidermal growth factor receptor (EGFR) family has been suggested in colon cancer etiology, progression, and/or severity. Our recently identified pan-erbB inhibitor EGFR-related protein (ERRP) targets EGFRs by attenuating their activation and subsequent signaling leading to cellular growth inhibition. In the present study, we evaluated the therapeutic effectiveness of ERRP on early and intermediate stages of colon cancer by examining regression of chemically induced aberrant crypt foci (ACF) in the colon of CF1 mice and intestinal adenomas in APC(Min+/-) (Min) mice. After formation of ACF or adenomas, the mice were injected (i.p.) with ERRP (50 microg/mouse) for 10 consecutive days. This treatment significantly reduced the number of ACF from 25.0 +/- 3.0 (controls) to 14.9 +/- 1.6 (ERRP-treated; P = 0.011) and also reduced their size (P < 0.01). In Min mice, ERRP caused the regression of adenomas throughout the small intestine (P < 0.05) and reduced their size (P < 0.001). This could partly be attributed to inhibition of proliferation and stimulation of apoptosis in the intestinal mucosa and was associated with decreased activation of several EGFR family members, suppression of downstream effector nuclear factor kappaB and down-regulation of cyclooxygenase-2. ERRP-induced attenuation of EGFR activation could be due to increased sequestration of the ligand(s) by ERRP, rendering them unavailable for binding to and activation of the receptor. In conclusion, our data show that ERRP is effective in regressing both early and intermediate intestinal lesions and could be an effective therapeutic agent for colon cancer.

Topics: 1,2-Dimethylhydrazine; Adenoma; Animals; Apoptosis; Carcinogens; Cell Growth Processes; Colonic Neoplasms; Drosophila Proteins; ErbB Receptors; Female; Intestinal Mucosa; Male; Mice; Mice, Inbred C57BL; Neoplasm Staging; NF-kappa B; Precancerous Conditions; Receptors, Estrogen; Recombinant Fusion Proteins; Transforming Growth Factor alpha

Growth factors have been implicated in pancreatic carcinogenesis. In this study we analyzed the effect of Tgfa overexpression in addition to mutant Kras(G12D) by crossing Elastase-Tgfa mice with p48(+/Cre);Kras(+/LSL-G12D) mice. We show that concomitant expression of TGFalpha and Kras(G12D) accelerates the progression of mPanIN lesions to metastatic pancreatic cancer and leads to the development of cystic papillary lesions resembling human intraductal papillary mucinous neoplasms (IPMN). Microarray data in mice revealed an IPMN signature and IPMNs expressed MUC1 and MUC5AC but not MUC2, similar to human pancreatobiliary IPMNs. Invasive ductal adenocarcinoma developed from PanINs and IPMNs, suggesting precursor lines for both lesion types in this model. In conclusion, Egfr signaling in synergy with oncogenic Kras may be a prerequisite for IPMN development and progression to pancreatic cancer.

Topics: Animals; Carcinoma, Pancreatic Ductal; Cell Differentiation; Genes, ras; Humans; Mice; Mice, Transgenic; Mutation; Oncogene Protein p21(ras); Pancreatic Elastase; Pancreatic Neoplasms; Precancerous Conditions; Promoter Regions, Genetic; Signal Transduction; Transforming Growth Factor alpha

Intrahepatic transplantation of ovarian fragments in ovariectomized rats results in morphological abnormalities. The liver acini draining blood from ovarian grafts show alterations resembling chemically induced amphophilic hepatocellular preneoplasias. We investigated the long-term development of these estrogen-induced foci of altered hepatocytes (FAH). We divided 451 Lewis rats into one main group (MG) and 11 (7 female, 4 male) control groups and observed them for up to 30 months. MG animals were ovariectomized and received ovarian transplants into the right liver part. Different combinations of castration, transplantation of ovarian or testicular fragments, and administration of antiestrogenic toremifene were used in controls. In the MG, transplants showed signs of gonadotropic stimulation, and estrogen levels were strongly increased in the downstream liver acini. After 6 and 12 months, FAH developed in hepatocytes downstream of the transplants. After 18 months, 27% of the MG animals showed transformation of FAH into hepatocellular adenomas; this figure increased to 42% after 24 months (8/19), significantly outnumbering four spontaneous adenomas that developed between 18 and 30 months in 258 control animals. Hepatocellular carcinoma (HCC) appeared only in the MG. At 24 and 30 months, 18 HCCs developed; thus, 78% of MG animals showed at least one carcinoma. Administration of toremifene in ovariectomized and transplanted animals completely prevented hepatocarcinogenesis. Testicular grafts showed no influence on liver tissue. In conclusion, initially adaptive but preneoplastic alterations in hepatocytes downstream of intrahepatically transplanted ovarian fragments may transform into HCC, indicating a strong hepatocarcinogenic potential of high local levels of endogenous estrogens in the rat liver.

Topics: Adenoma, Liver Cell; Animals; Aorta; Carcinoma, Hepatocellular; Estradiol; Estrogen Antagonists; Estrogens; Female; Gonadal Steroid Hormones; Gonadotropins; Hepatic Veins; Hepatocytes; Immunohistochemistry; Liver; Liver Neoplasms; Male; Ovariectomy; Ovary; Precancerous Conditions; Rats; Rats, Inbred Lew; Testis; Toremifene; Transforming Growth Factor alpha; Transplantation, Heterotopic

Prolactin influences mammary development and carcinogenesis through endocrine and autocrine/paracrine mechanisms. In virgin female mice, pro-lactin overexpression under control of a mammary selective nonhormonally responsive promoter, neu-related lipocalin, results in estrogen receptor alpha (ERalpha)-positive and ERalpha-negative adenocarcinomas. However, disease in vivo occurs in the context of dysregulation of multiple pathways. In this study, we investigated the ability of prolactin to modulate carcinogenesis when co-expressed with the potent oncogene transforming growth factor alpha (TGFalpha) in bitransgenic mice. Prolactin and TGFalpha cooperated to reduce dramatically the latency of mammary macrocyst development, the principal lesion type induced by TGFalpha. In combination, prolactin and TGFalpha also increased the incidence and reduced the latency of other preneoplastic lesions and increased cellular turnover in structurally normal alveoli and ducts compared with single transgenic females. Bitransgenic glands contained higher levels of phosphorylated ERK1/2 compared with single TGFalpha transgenic glands, suggesting that this kinase may be a point of signaling crosstalk. Furthermore, transgenic prolactin also reversed the decrease in ERalpha induced by neu-related lipocalin-TGFalpha. Our findings demonstrate that locally produced prolactin can strikingly potentiate the carcinogenic actions of another oncogene and modify ovarian hormone responsiveness, suggesting that prolactin signaling may be a potential therapeutic target.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Estrogen Receptor alpha; Female; Humans; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mice; Mice, Transgenic; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Phosphorylation; Precancerous Conditions; Prolactin; Transforming Growth Factor alpha

Expression of TGF-alpha during promotion of neoplastic development from GST-P-positive foci in rat chemical hepatocarcinogenesis was investigated. One-hundred male F344 rats were given a single intraperitoneal injection of DEN (200 mg/kg bodyweight) and subjected to two-thirds partial hepatectomy at week 3. Commencing 2 weeks from the start, PB at doses of 0 or 500 p.p.m. was fed to the rats for 46 weeks. Groups of 10 rats were killed at weeks 4, 8, 16, 32, 48 and their livers were immunohistochemically examined for expression of GST-P and TGF-alpha. TGF-alpha-positive foci and single positive cells were observed from week 4, partially overlapping with GST-P-positive foci but being much fewer. Numbers of TGF-alpha-positive lesions did not increase from weeks 4-48, but their areas showed increment at weeks 32 and 48, especially with PB administration. Almost all of the tumors observed at weeks 16, 32 and 48 were positive for TGF-alpha (98%). In addition, epidermal growth factor receptor overexpression was observed in most TGF-alpha-positive lesions (foci and tumors). The proliferating cell nuclear antigen labeling index in double positive foci for GST-P and TGF-alpha was significantly higher than that in TGF-alpha-negative foci. In conclusion, TGF-alpha may be closely related with promotion from altered foci to neoplasms in rat hepatocarcinogenesis. Our data suggest that double positive foci for GST-P and TGF-alpha in the early stages of rat hepatocarcinogenesis may develop into tumors with promotion.

Topics: Animals; Carcinogenicity Tests; Carcinogens; Diethylnitrosamine; Glutathione S-Transferase pi; Hepatectomy; Immunohistochemistry; Liver Neoplasms, Experimental; Male; Phenobarbital; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Rats; Transforming Growth Factor alpha

To measure HPV status, epidermal growth factor receptor (EGFR) and transforming growth factor-alpha (TGF-alpha) expression and Ki-67 index in exophytic papilloma (EP), inverted papilloma (IP) with dysplasia, IP with carcinoma and invasive squamous cell carcinoma (SCC).. Forty-four patients with sinonasal papilloma and invasive SCC were selected. The nasal tissues were stained with monoclonal antibodies to EGFR, TGF-alpha and Ki-67. The results were analysed using quantitative immunohistochemical analysis. In situ hybridization studies for HPV DNA for 6/11, 16/18 and 31/33 were also performed on the tissue.. Significant increase of EGFR and TGF-alpha was observed in IP with severe dysplasia, IP with carcinoma and invasive SCC compared to IP with mild dysplasia and control nasal mucosa. And a serial upreguration in terms of Ki-67 index in IP with dysplasia was observed. Among IP, HPV 6/11-positive was present in 42% tumour and HPV 16/18-positive was present in 31% of tumours. Among HPV 6/11 and 16/18-positive IP, significant increase of EGFR and Ki-67 index were observed.. Pre-cancerous lesions of IP exhibited elevated levels of EGFR and TGF-alpha and these expression may be associated with early events in IP carcinogenesis. HPV infection may be an early event in a multistep process of malignant formation of IP.

Topics: Antibodies, Monoclonal; Biomarkers, Tumor; Carcinoma; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; ErbB Receptors; Female; Humans; In Situ Hybridization; Ki-67 Antigen; Male; Middle Aged; Nasal Mucosa; Neoplasm Invasiveness; Nose Neoplasms; Papilloma; Papilloma, Inverted; Papillomaviridae; Paranasal Sinus Neoplasms; Precancerous Conditions; Transforming Growth Factor alpha

Studies of cellular interactions are critical to the understanding of tumorigenesis. Although many studies have demonstrated a monoclonal composition of advanced neoplasms in humans and mice, the clonal composition of smaller, antecedent lesions has been studied less thoroughly. To examine the clonal development of breast cancer, we generated chimeric mammary glands using mouse mammary epithelium with an inherited predisposition for neoplasia. Analysis of whey acidic protein-transforming growth factor-alpha transgenic mouse mammary glands, chimeric for two different cell lineage markers, revealed that mammary ducts and alveoli are polyclonal, and putative early preneoplastic lesions, hyperplastic alveolar nodules (HANs), frequently are polyclonal. Furthermore, the chimeric patch patterns in individual HANs were similar to the patterns observed in pregnant chimeric mammary glands. Thus, polyclonality in HANs appears to reflect persistence of the polyclonal architecture of ducts and/or alveoli, suggesting that hyperplasia formation can be the result of non-cell autonomous local tissue microenvironmental influences on groups of cells, rather than clonal progression of a single initiated cell.

Topics: Alkaline Phosphatase; Animals; Cell Lineage; Clone Cells; Female; Keratins; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mice; Mice, Transgenic; Precancerous Conditions; Transforming Growth Factor alpha; Transgenes; Transplantation Chimera

Previous studies have indicated that increased expression of TGFalpha and cyclin E are correlated with the oncogenesis and progress of cancer; however, their expression patterns in gastric precancerous lesions have been not clear yet. In addition, the association between expression of TGFalpha and cyclin E has not been reported. This study was designed to investigate the expression of TGFalpha and cyclin E in chronic superficial gastritis (CSG), gastric precancerous lesions, and gastric carcinoma (GCA), and analyze the association of TGFalpha and cyclin E expression, and the relationship between their expression and different development stages of oncogenesis of GCA.. The expression of TGFalpha and cyclin E in CSG, intestinal metaphases (IM), atypical hyperplasia (AH), and GCA were examined using immunohistochemical staining. The association of TGFalpha and cyclin E expression was also statistically analyzed.. The expression rates of TGFalpha and cyclin E were 15.1%, 53.6%, 51.7%, 61.7%, and 7.5%, 28.6%, 37.9%, 42.6% in tissue samples of CSG, IM, AH and GCA, respectively. The positive expression rates of TGFalpha and cyclin E were higher in IM, AH, GCA than in CSG; the difference was significant (each P< 0.05). In addition, the positive expression rates of TGFalpha and cyclin E were higher in low differential adenocarcinoma (TGFalpha 81.0%, cyclin E 57.1%) than in mediate to high differential one (TGFalpha 41.7%, cyclin E 16.7%) (P< 0.05,for both TGFalpha and cyclin E). It is also revealed that the expression of TGFalpha and cyclin E were closely associated (P< 0.001 for the tissue of gastric chronic inflammation, and P=0.005 for gastric carcinoma, respectively).. In the tissues of CSG, IM, AH, and GCA, the expression rates of TGFalpha and cyclin E are increased gradually with the severity of the pathological lesions and the malignancy of GCA. In addition, the expression of TGFalpha and cyclin E were obviously associated.

Topics: Adolescent; Adult; Aged; Chronic Disease; Cyclin E; Female; Gastritis; Humans; Immunohistochemistry; Male; Middle Aged; Precancerous Conditions; Stomach Neoplasms; Transforming Growth Factor alpha

The pro-peptide of transforming growth factor alpha (proTGFalpha) was recently found in hepatocyte nuclei preparing for DNA replication, which suggests a role of nuclear proTGFalpha for mitogenic signalling. This study investigates whether the nuclear occurrence of the pro-peptide is involved in the altered growth regulation of (pre)malignant hepatocytes. In human hepatocarcinogenesis, the incidence of proTGFalpha-positive and replicating nuclei gradually increased from normal liver, to dysplastic nodules, to hepatocellular carcinoma. ProTGFalpha-positive nuclei almost always were in DNA synthesis. Also, in rat hepatocarcinogenesis, proTGFalpha-positive nuclei occurred in (pre)malignant hepatocytes at significantly higher incidences than in unaltered hepatocytes. For functional studies unaltered (GSTp(-)) and premalignant (GSTp(+)) rat hepatocytes were isolated by collagenase perfusion and cultivated. Again, DNA synthesis occurred almost exclusively in proTGFalpha-positive nuclei. GSTp(+) hepatocytes showed an approximately 3-fold higher frequency of proTGFalpha-positive nuclei and DNA replication than GSTp(-) cells. Treatment of cultures with the mitogen cyproterone acetate (CPA) elevated the incidence of proTGFalpha-positive nuclei and DNA synthesis in parallel. Conversely, transforming growth factor beta1 (TGFbeta1) lowered both. These effects of CPA and TGFbeta1 were significantly more pronounced in GSTp(+) than in GSTp(-) hepatocytes. In conclusion, nuclear translocation of proTGFalpha increases in the course of hepatocarcinogenesis and appears to be involved in the inherent growth advantage of (pre)malignant hepatocytes.

Topics: Animals; Antineoplastic Agents; Cell Nucleus; Cyproterone Acetate; DNA; DNA Replication; Glutathione Transferase; Hepatocytes; Liver Neoplasms; Male; Precancerous Conditions; Protein Transport; Rats; Rats, Wistar; Transforming Growth Factor alpha; Transforming Growth Factor beta; Transforming Growth Factor beta1

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

LT97, a permanent cell line consisting of epithelial cells with an early premalignant genotype was established from small colorectal polyps. LT97 cells have lost both alleles of the APC tumour suppressor gene. In addition, they carry a mutated Ki-ras oncogene, while TP53 is normal. LT97 growth characteristics are thus representative of early adenomas. They had to be passaged as multicellular aggregates indicating a dependency of survival on cell-cell contact and in accordance with their premalignant genotype were not capable of growth in soft agar. LT97 cells did express both the EGF-receptor and small amounts of TGF(alpha) establishing an autocrine growth or survival pathway. However, in spite of autocrine TGF(alpha) production, growth was strongly dependent on exogenous growth factors--mainly EGF, insulin and HGF. Inhibition of the EGF-receptor kinase induced apoptosis at an IC(50) concentration of 4 micromolar indicating that TGF(alpha) activated survival pathways in the early adenoma cell.

Topics: Adenoma; Apoptosis; Cell Division; Colonic Neoplasms; Flow Cytometry; Genes, ras; Humans; Mutation; Precancerous Conditions; Transforming Growth Factor alpha; Tumor Cells, Cultured

Human pancreatic adenocarcinoma has an overall poor prognosis. Therapeutic efforts are often ineffective because of late diagnosis and a high degree of chemoresistance. Overexpression of transforming growth factor alpha in the pancreas of transgenic mice causes the formation of premalignant ductal lesions and the development of invasive ductal adenocarcinoma. The aim of the present study was to explore regulation of proapoptotic and antiapoptotic signals during pancreatic tumor development in mice.. EL-TGFalpha-hGH transgenic mice crossbred to p53-deficient mice develop ductal pancreatic adenocarcinoma resembling the human disease. During the multistep carcinogenesis up-regulation of Bcl-x(L) is evident early and persists throughout tumorigenesis as detected by Real Time PCR, Western blot analysis, and immunofluorescence.. Up-regulation of Bcl-x(L) is evident early in tumor development and persists throughout tumorigenesis. The transcription factors Stat3 and NF-kappaB induce increased Bcl-x(L) expression in the premalignant lesions and tumor cells. Inhibition of either transcription factor alone leads to Bcl-x(L) down-regulation in transient transfection assays. Functional analysis shows that blocking of both Stat3 and NF-kappaB together induces programmed cell death in murine pancreatic tumor cells.. These findings indicate that apoptosis resistance precedes formation of invasive pancreatic cancer. Therefore, combined inhibition of Stat3 and NF-kappaB might represent a novel strategy for tumor prevention and therapy.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Carcinoma, Ductal, Breast; Cell Line; Cells, Cultured; DNA-Binding Proteins; Down-Regulation; Mice; Mice, Transgenic; NF-kappa B; Pancreatic Neoplasms; Phenotype; Precancerous Conditions; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; STAT3 Transcription Factor; Trans-Activators; Transforming Growth Factor alpha; Tumor Suppressor Protein p53; Up-Regulation

This study was conducted to evaluate the clinical significance of the localization of epidermal growth factor receptor (EGF-r), transforming growth factor (TGF)-alpha, and erbB-2 in the development, progression and prognosis of squamous cell cancers (SCCs) of the lung.. The localization of EGF-r, TGF-alpha, and erbB-2 was evaluated immunohistochemically in 60 archival specimens of SCC of the lung and in 60 lung specimens without cancer. To clarify the patterns of expression of EGF-r in these tumors, the patterns of expression of EGF-r in cells in culture were monitored after challenging normal human bronchial epithelial and SCC cell lines with either EGF or TGF-alpha at physiological concentrations.. The expression of EGF-r, erbB-2, and TGF-alpha were significantly higher in SCC and associated precancerous lesions than in the normal bronchial epithelium and hyperplastic lesions of noncancer specimens. A statistically significant stepwise increase in expression from uninvolved bronchial epithelium to precancerous lesions to SCC was observed with EGF-r and TGF-alpha. The localization of EGF-r in the cytoplasm (P = 0.04), but not in the membrane (P = 0.20), of SCCs was significantly associated with poor overall survival of subjects. To demonstrate the biological relevance of cytoplasmic expression of EGF-r, we noted that there was a prompt reduction in the membrane expression and a concomitant increase in cytoplasmic expression of EGF-r after adding either EGF or TGF-alpha to the cell culture medium. Overall, the study identified an involvement of EGF-r and TGF-alpha in the development of SCCs. The prognostic importance of EGF-r expression in the cytoplasm of lung cancer probably is an indication of the prognostic importance of trafficking of the EGF-r receptor between the Golgi apparatus and cell membranes and of internalization of EGF-r after an interaction with one of the EGF-r ligands at the cellular membrane surface.

Topics: Carcinoma, Squamous Cell; Cell Membrane; Cytoplasm; Epithelial Cells; ErbB Receptors; Humans; Hyperplasia; Immunoenzyme Techniques; Ligands; Lung Neoplasms; Precancerous Conditions; Prognosis; Receptor, ErbB-2; Survival Rate; Transforming Growth Factor alpha; Tumor Cells, Cultured

Expression of TGFalpha and the EGF receptor was studied in relation to apoptosis in human colorectal mucosa and premalignant and malignant tumors. In normal mucosa the proteins colocalized both in the proliferation compartment and at the luminal pole of the crypts in cells committed to undergo apoptosis. While staining for the EGF receptor was increased in premalignant and malignant lesions, TGFalpha was undetectable in aberrant crypt foci as well as large areas of adenomas. Incidence of apoptosis (AI) was high in these areas ranging from 8.83-24.59. Adenomas did, however, contain islands of high TGFalpha expression where AI was decreased to a range of 0.76-4.00 (decreased at P=0.0027). In carcinomas TGFalpha expression was increased above both normal and adenoma levels corresponding to the decrease in apoptosis in the malignant tumors. Tissue localization of TGFalpha and AI were still inversely related ( P=0.022), but interpatient variability was much larger than for adenomas. The data indicate that TGFalpha is the main survival factor in premalignant tumor cells of the colon, while additional factors moderate its effect in carcinomas. This suggests the possibility of targeting the EGF receptor pathway not only for treatment but also for the reversal of adenoma growth and the prevention of malignant colorectal tumors.

Topics: Apoptosis; Colorectal Neoplasms; Humans; Immunohistochemistry; Intestinal Mucosa; Precancerous Conditions; Transforming Growth Factor alpha

Renal cell carcinoma (RCC) is the most malignant urologic disease. Different lesions, such as dysplasia in the tubules adjacent to RCC, atypical hyperplasia in the cyst epithelium of von Hippel-Lindau syndrome, and adenoma have been described for a number of years as possible premalignant changes or precursor lesions of RCC. In two recent papers, kidneys adjacent to RCC or removed from other causes were analyzed, and dysplastic lesions were identified and defined in detail. Currently renal intraepithelial neoplasia (RIN) is the proposed term for classification. The criteria for a lesion to be defined as premalignant are (1) morphological similarity; (2) spatial association; (3) development of microinvasive carcinoma; (4) higher frequency, severity, and extent then invasive carcinoma; (5) progression to invasive cancer; and (6) similar genetic alterations. RIN resembles the neoplastic cells of RCC. There is spatial association. Progression to invasive carcinoma is described in experimental cancer models, and in some human renal tumors. Similar molecular alterations are found in some putative premalignant changes. The treatment for RCC is radical or partial nephrectomy. Preneoplastic lesions may remain in the renal remnant in patients treated by partial nephrectomy and may be the source of local recurrences. RIN seems to be a biologic precursor of some RCCs and warrants further investigation. Interpretation and reporting of these lesions would reveal important resources for the biological nature and clinical significance. The management of RIN diagnosed in a renal biopsy and partial nephrectomy needs to be answered.

Topics: Carcinoma, Renal Cell; ErbB Receptors; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Incidence; Kidney; Kidney Neoplasms; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Terminology as Topic; Transforming Growth Factor alpha; Tumor Suppressor Protein p53; United States

The role of transforming growth factor alpha (TGFalpha) and prostaglandins (PGs) in the preferential growth of preneoplastic liver cells was studied. Rats received the genotoxic hepatocarcinogen N-nitrosomorpholine (NNM); placental glutathione S-transferase (GSTp) was used as a marker to identify preneoplastic foci. Preneoplastic foci expressing TGFalpha (TGFalpha(+)) grew more rapidly than TGFalpha negative (TGFalpha(-)) ones. Almost all tumours studied were positive for TGFalpha. The key enzymes of prostaglandin synthesis, cyclooxygenase I (Cox-1) and II (Cox-2), were present in all unaltered and preneoplastic cells and tended to decrease in the later stages of hepatocarcinogenesis. Immunostaining revealed that cultures of hepatocytes, isolated from NNM-treated livers by collagenase perfusion, contained 1-2% GSTp-positive (GSTp(+)) and 9% TGFalpha(+) hepatocytes; 0.6% of the cells were GSTp(+)/TGFalpha(+). Cox-1 and Cox-2 were present in all cells. DNA replication was almost exclusively associated with expression of TGFalpha. GSTp(+) hepatocytes showed a 3- to 4-fold higher probability of TGFalpha expression and of DNA synthesis than GSTp-negative (GSTp(-)) cells. PGE(2) or PGF(2alpha) increased expression of TGFalpha and DNA replication in GSTp(-) cells but not in GSTp(+) cells. PGA(2) and PGJ(2) decreased DNA synthesis in TGFalpha(+) cells without an obvious effect on the intracellular levels of TGFalpha. The Cox-2 inhibitor SC236 suppressed DNA replication preferentially in GSTp(+) cells; this inhibition was reversed by PGE(2)/F(2alpha). Indomethacin had no effect. These results suggest the following conclusions. (i) Growth regulation of preneoplastic GSTp(+) cells in culture exhibits distinct differences from GSTp(-) cells and elevated expression of TGFalpha contributes to their growth advantage. (ii) TGFalpha renders preneoplastic hepatocytes sensitive to suppression of DNA synthesis by PGA(2)/J(2). (iii) SC236, a Cox-2 inhibitor, may have preventive value in hepatocarcinogenesis.

Topics: Animals; Apoptosis; Cell Division; Cyclooxygenase Inhibitors; DNA Replication; Glutathione Transferase; Hepatocytes; Liver Neoplasms, Experimental; Male; Precancerous Conditions; Prostaglandins; Rats; Rats, Wistar; Transforming Growth Factor alpha

Previous work has shown that phenobarbital (PB) can promote cell survival in double transgenic c-myc/transforming growth factor (TGF)-alpha mice. This was achieved through a suppression of cell death brought about, at least in part, by a general increase in the level of bcl-2 protein and a decrease in TGF-beta1 in treated versus untreated animals. No changes were found in TGF-beta type II receptor or in bcl-X(L) protein levels. In the present work, we followed these animals for up to 31 wk of age (28 wk of treatment), by which time numerous tumors could be observed. A PB-dependent decrease in tumor latency and a significant increase in multiplicity were seen. No statistically significant changes in the phenotype of foci, nodules, or neoplasms were observed after PB administration, and no effect on median tumor size was detected. Levels of the anti-apoptotic protein bcl-2 did not correlate with tumor formation in PB-treated animals. However, in untreated mice, bcl-2 was higher in tumors than in surrounding tissue in all tumors examined. We believe that the PB-dependent modification of tumorigenesis in the livers of c-myc/TGF-alpha mice was predominantly a result of the ability of this drug to block cell death during the early stages of tumor development. The effect of PB was exerted apparently by a pathway similar to, but separate from, that of TGF-alpha. However, these pathways appear to converge downstream, having common effectors in the form of bcl-2 family proteins. Mol. Carcinog. 28:168-173, 2000.

Topics: Animals; Apoptosis; bcl-X Protein; Carcinogens; Cell Transformation, Neoplastic; Crosses, Genetic; Genes, myc; Genes, Synthetic; Genetic Predisposition to Disease; Humans; Liver Neoplasms, Experimental; Metallothionein; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Transgenic; Neoplasm Proteins; Phenobarbital; Precancerous Conditions; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Transforming Growth Factor alpha; Transgenes

Human cDNAs corresponding to two epidermal growth factor-related products that are overexpressed in human breast cancers, that for c-erbB-2 (HER-2) and for transforming growth factor alpha (TGFalpha), have been cloned downstream of the mouse mammary tumor virus (MMTV) long terminal repeat promoter and injected into the pronucleus of fertilized oocytes of Sprague-Dawley rats to produce transgenic offspring. Expression of the transgenic mRNAs is not detectable in mammary tissue from virgin transgenic rats but is detected in mammary tissue from certain lines of mid-pregnant transgenic rats. When two such lines of either type of transgenic rat are subjected to repeated cycles of pregnancy and lactation, they produce, primarily in the mammary glands, extensive pathologies, whereas virgin transgenic rats produce no such abnormalities. Multiparous transgenic female offspring from c-erbB-2-expressing lines develop a variety of focal hyperplastic and benign lesions that resemble lesions commonly found in human breasts. These lesions include lobular and ductal hyperplasia, fibroadenoma, cystic expansions, and papillary adenomas. More malignant lesions, including ductal carcinoma in situ and carcinoma, also develop stochastically at low frequency. The mammary glands of transgenic females invariably fail to involute fully after lactation. Similar phenotypes are observed in female MMTV-TGFalpha transgenic rats. In addition, multiparous TGFalpha-expressing female transgenics frequently develop severe pregnancy-dependent lactating hyperplasias as well as residual lobules of hyperplastic secretory epithelium and genuine lactating adenomas after weaning. These transgenic rat models confirm the conclusions reached in transgenic mice that overexpression of the c-erbB-2 and TGFalpha genes predisposes the mammary gland to stochastic tumor development.

Topics: Animals; Animals, Genetically Modified; Female; Gene Expression; Hyperplasia; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Precancerous Conditions; Pregnancy; Rats; Rats, Sprague-Dawley; Receptor, ErbB-2; Transforming Growth Factor alpha

The development of head and neck squamous cell carcinoma occurs as a result of the accumulation of genotypic and phenotypic alterations in the upper aerodigestive tract mucosa. Up-regulation of epidermal growth factor receptor (EGFR) and its ligand, transforming growth factor alpha (TGF-alpha), have been identified previously as early events in head and neck carcinogenesis. To determine the timing of increased TGF-alpha and EGFR protein expression in the development of head and neck cancer, we examined progressive mucosal dysplasias from three distinct and complimentary patient groups: (a) samples from patients with lesions demonstrating different degrees of dysplasia (n = 22) compared with mucosa samples from gender and age-matched controls (n = 8); (b) patients with lesions demonstrating different degrees of dysplasia at a single time point (n = 3); and (c) patients who progressed over several years to invasive cancer at the site of dysplasia (n = 7). Immunohistochemical analysis with monoclonal antibodies specific for TGF-alpha and EGFR were used to detect protein expression in all specimens. Protein levels were further quantitated using a computerized image analysis system. In all three groups, we found that TGF-alpha protein levels were elevated in mild dysplasia compared with control normal mucosa and were not further modulated with increasing degrees of dysplasia. In contrast, EGFR levels were relatively low in mild dysplasia and increased with higher degrees of dysplasia. These findings indicate that up-regulation of TGF-alpha and EGFR are distinct events both chronologically and, possibly, mechanistically in the pathogenesis of head and neck squamous cell carcinoma.

Topics: Carcinoma, Squamous Cell; ErbB Receptors; Female; Head and Neck Neoplasms; Humans; Immunohistochemistry; Male; Precancerous Conditions; Transforming Growth Factor alpha

To investigate the patterns of expression of transforming growth factor alpha (TGF-alpha) and epidermal growth factor receptor (EGFR) in squamous metaplasia and squamous cell carcinomas of the urinary bladder with and without schistosomiasis.. Immunohistochemical study of the expression of TGF-alpha and EGFR in squamous metaplasias (n = 12) and various grades of squamous cell carcinomas (n = 21) of the bladder with and without schistosomiasis.. Focal cytoplasmic and membranous positivity for EGFR and TGF-alpha was seen in all cases of squamous metaplasia. The markers were diffusely coexpressed in a concordant pattern in areas of hyperplastic keratinising squamous metaplasia. A similar pattern of positivity was seen in verrucous carcinomas (n = 2) and well differentiated squamous carcinomas (n = 6). Progressive loss of differentiation was associated with increasing loss of EGFR staining while TGF-alpha staining was retained. Squamous cell carcinoma in situ (n = 2) showed focal positivity for TGF-alpha and EGFR. There were no differences in staining patterns between cases with and without schistosomiasis.. The coexpression of TGF-alpha and EGFR by well differentiated squamous cell carcinomas and hyperplastic keratinising squamous metaplasia is consistent with the active regulatory role exerted by this autocrine loop. There is regional absence of expression of EGFR but not of TGF-alpha in squamous cell carcinomas of lesser differentiation, suggesting heterogeneity of such control in these tumours. The focal expression of the two markers in squamous cell carcinomas in situ indicates a possible second pathway of oncogenesis for less differentiated tumours. These observations may have important implications for the effectiveness of putative growth factor based treatments.

Topics: Adult; Aged; Carcinoma, Squamous Cell; ErbB Receptors; Female; Humans; Male; Metaplasia; Middle Aged; Neoplasm Proteins; Precancerous Conditions; Schistosomiasis haematobia; Transforming Growth Factor alpha; Urinary Bladder; Urinary Bladder Neoplasms

Analysis of growth factors and receptors in putative premalignant lesions of prostatic adenocarcinoma should aid our understanding of their growth pathways. Sixty prostatic TURP (transurethral resection of the prostate) specimens exhibiting atypical adenomatous hyperplasia (AAH) and/or prostatic intraepithelial neoplasia (PIN) lesions were assayed by immunohistochemistry for androgen receptor (AR), epidermal growth factor receptor (EGFR), c-erbB-2, transforming growth factor-alpha (TGF-alpha), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), MIB-1, E-cadherin, and high molecular weight keratin. Expression of these factors in the lesions was compared with that in the co-existing benign prostatic hyperplasia (BPH) or prostatic adenocarcinoma. Strong AR nuclear staining was observed in the luminal cells, but not the basal cells, of BPH and PIN lesions and in all the carcinomas examined. A similar growth factor and receptor profile was demonstrated in the secretory epithelium of high-grade PIN and carcinoma with a tendency to higher expression of membranous EGFR and c-erbB-2 and cytoplasmic TGF-alpha, and lower levels of FGF-2 than in low-grade PIN or BPH glands. Also, increased rates of proliferation, as estimated by MIB-1 stained cells, were observed in high-grade PIN in comparison with low-grade PIN and BPH and were not confined to the basal layer. AAH lesions resembled neither BPH nor carcinoma. Proliferation was virtually absent (MIB-1 expression); both AR and E-cadherin expression was significantly reduced; and, with the exception of FGF-2, all the other growth factors and receptors studied were absent. The results presented would support a premalignant role for high-grade PIN, whilst AAH would appear to represent a quiescent phenotype unlikely to progress to neoplasia.

Topics: Antigens, Nuclear; Cadherins; Endothelial Growth Factors; ErbB Receptors; Fibroblast Growth Factor 2; Growth Substances; Humans; Ki-67 Antigen; Lymphokines; Male; Nuclear Proteins; Precancerous Conditions; Prostatic Hyperplasia; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; Receptor, ErbB-2; Receptors, Androgen; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Despite extensive research, the mechanisms of prostate carcinogenesis are not well understood. The slow progress in this area is due, at least in part, to lack of a suitable animal model for prostate carcinogenesis. We have developed an animal model, based on the existing sex hormone-induced prostate carcinogenesis in the Noble rat, by substantially increasing the dosage of testosterone while keeping the level of estrogen unchanged. Using the modified method of combination of testosterone and estradiol-17beta (T+E2), it has been shown in Noble rats that prostate carcinogenesis followed a multi-step process involving hyperplasia, dysplasia, and carcinoma. We have demonstrated the importance of TGF-alpha, TGF-beta1 and bFGF in the development of prostate carcinogenesis. This study also established the roles of VEGF and IGF-1, initially as paracrine factors in epithelial-stromal interactions during the process of carcinogenesis and subsequently switching over to an autocrine mode during the establishment of carcinoma.

Topics: Adenocarcinoma; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Therapy, Combination; Endothelial Growth Factors; Estradiol; Fibroblast Growth Factor 2; Hyperplasia; Immunohistochemistry; Lymphokines; Male; Precancerous Conditions; Prostate; Prostatic Neoplasms; Rats; Rats, Inbred Strains; Receptor Protein-Tyrosine Kinases; Receptors, Growth Factor; Receptors, Vascular Endothelial Growth Factor; Testosterone; Transforming Growth Factor alpha; Transforming Growth Factor beta; Transforming Growth Factor beta1; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

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

Many studies have been conducted to assess the potential preneoplastic nature of colonic aberrant crypt foci (ACF), but still the biological significance of these foci and their relationship to colon neoplasia remains to be elucidated. In the present paper a battery of variables suggested to be indicative for colon cancer development has been studied in relation to ACF in rats. These include: (i) the degree of dysplasia; (ii) the type of mucus production; (iii) the cellular immunohistochemical expression and distribution of transforming growth factors alpha and beta and their respective receptors, epidermal growth factor receptor and transforming growth factor beta receptors I and II and phosphorylated cellular tyrosine. The parameters have been investigated in ACF selected from a previous study where the foci were induced under different circumstances, leading to disparities in the number as well as the crypt multiplicity obtained. The present study showed that for all parameters investigated, apart from sialomucin production, the different experimental conditions had no effect on the individual ACF, irrespective of the number and distribution of the different categories of ACF among the various diets. However, it was shown that the degree of dysplasia correlated strongly with crypt multiplicity and that all the investigated ACF lacked expression of transforming growth factor alpha and expressed a reduced amount of transforming growth factor beta compared with normal crypts. These observations may indicate that ACF are preneoplastic lesions and supports the suggestion that they may, at least in the rat, have the potential to gradually progress to tumors, but no single ACF showed particular characteristics indicating specific proneness to tumor development. The study could not confirm the presence of sialomucin-producing ACF as a valid marker for tumor development.

Topics: Animals; Cell Transformation, Neoplastic; Colon; Colonic Neoplasms; Dietary Fats; Dietary Fiber; Dietary Sucrose; ErbB Receptors; Gene Expression Regulation; Growth Substances; Intestinal Mucosa; Male; Mucins; Precancerous Conditions; Rats; Receptors, Growth Factor; Receptors, Transforming Growth Factor beta; Sialomucins; Transforming Growth Factor alpha; Transforming Growth Factor beta

Transforming growth factor-alpha (TGF-alpha) is a multifunctional cell regulatory protein with a wide range of effects on cell growth and differentiation and has been implicated in the neoplastic transformation of a variety of cell types. Altered expression of TGF-alpha and its cognate receptor (epidermal growth factor receptor) is enhanced in human and rat renal cell carcinomas. The objective of the study reported here was to determine whether altered TGF-alpha expression is an early or late event in renal tubular oncogenesis. The immunohistochemical expression of TGF-alpha was studied in preneoplastic renal tubular lesions in a rat model of hereditary renal cell carcinoma. Strong TGF-alpha immunoreactivity was present at all stages of renal cell tumor development, including the earliest detectable dysplasias. In contrast, the non-neoplastic regenerating tubular epithelium of rat degenerative nephropathy did not stain for TGF-alpha, although this tissue exhibited a proliferative capacity similar to that observed in the dysplastic and neoplastic lesions. This study indicated that altered TGF-alpha expression was detectable early in the development of renal cell tumors and may be an important feature of the transformed phenotype.

Topics: Animals; Bromodeoxyuridine; Carcinoma, Renal Cell; Cell Division; Epithelial Cells; Epithelium; Kidney Neoplasms; Kidney Tubules; Phenotype; Precancerous Conditions; Rats; Rats, Inbred Strains; Transforming Growth Factor alpha

Transforming growth factor-alpha (TGF alpha) and epidermal growth factor receptor (EGF-R) mRNAs were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) in the normal and neoplastic mammary glands of four strains of mice with different mammary tumor potentials (from highest to lowest potential): SHN, GR/A, SLN and C3H/He. At 2 months of age, when the mammary glands of these strains consisted mostly of normal tissue, the samples examined showed the positive expressions of both TGF alpha and EGF-R mRNAs in all strains (4-6 mice per group), except for EGF-R mRNA in the SLN mice, expressed in only 2 of 4 samples associated with no end-bud formation in the mammary glands. At 10 months, all of the samples from all four strains had a positive expression of TGF alpha mRNA. The EGF-R mRNA expression paralleled the degree of the formation of preneoplastic hyperplastic alveolar nodules (HAN) in all strains. These findings indicate that TGF alpha and EGF-R participate in the growth of the mammary glands, and that EGF-R especially contributes to the formation of end-buds at younger ages and to that of preneoplastic HAN at later ages. All of the samples of mammary tumors from four strains had positive expressions of both TGF alpha and EGF-R mRNAs.

Topics: Animals; Cell Transformation, Neoplastic; Disease Susceptibility; ErbB Receptors; Female; Gene Expression Regulation, Neoplastic; Mammary Glands, Animal; Mammary Neoplasms, Animal; Mice; Mice, Inbred Strains; Polymerase Chain Reaction; Precancerous Conditions; RNA-Directed DNA Polymerase; RNA, Messenger; Transforming Growth Factor alpha

To assess the changes and possible role of expression of TGF-alpha and EGFR in gastric carcinogenesis and its relationship with PCNA labelling index (PCNA LI).. Immunohistochemical study using LSAB kit.. (1) The expression of TGF-alpha was increased in normal mucosa and metaplastic tissue near the carcinoma when compared with non-cancer controls (P < 0.01). (2) Increased expression of EGFR was found in the intestinal metaplastic and dysplastic areas compared with nomral mucosa and carcinoma tissue (P < 0.01). (3) Coexpression rate of TGF-alpha and EGFR was higher in dysplasia than in other tissues (P < 0.01). (4) There was a close correlation between the intensities of TGF-alpha, EGFR and PCNA. (5) The expression of TGF-alpha, EGFR and PCNA was not related to infiltration and lymph node metastasis of gastric carcinoma.. The increased expression of EGFR, TGF-alpha may serve as an important molecular marker of gastric premalignant lesions when combined with measurement of PCNA LI and may be of assistance in screening of early gastric carcinoma in high risk populations.

Topics: Biomarkers, Tumor; ErbB Receptors; Gastric Mucosa; Humans; Metaplasia; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Stomach; Stomach Neoplasms; Transforming Growth Factor alpha

Transforming growth factor-alpha (TGF alpha), a member of the epidermal growth factor receptor ligand family, has been implicated in the regeneration and transformation of liver. Our recent development of mice that are homozygous for a disrupted TGF alpha gene allowed us to assess the requirement for this growth factor in these complex processes. We report here that although a 70% hepatectomy produced a significant increase in hepatic TGF alpha protein levels in wild-type mice, liver regeneration nevertheless proceeded normally in the absence of the growth factor. The hepatocyte labeling indices determined for homozygous targeted and wild-type mice at 36 and 48 h after hepatectomy were comparable, and the total liver DNA to body weight ratios 8 d after hepatectomy were essentially identical for the two genotypes. These results indicate that TGF alpha, is not necessary for liver regeneration. To test its requirement in liver carcinogenesis, young mice were administered single doses of diethylnitrosamine (DEN) with or without subsequent chronic treatment with the promoting agent phenobarbital (PB). Both wild-type and homozygous mutant male mice treated with DEN or DEN plus PB developed multiple preneoplastic foci or tumors by 9 mo of age with relatively high incidence. However, while five of 88 tumors in wild-type mice attained a diameter greater than 5 mm and were classified as hepatocellular carcinomas, none of 132 tumors in livers of targeted mice reached this size. Furthermore, three of these large wild-type tumors expressed significantly elevated levels of TGF alpha protein compared with normal liver. These results indicate that TGF alpha is not required for early events in chemically induced hepatocarcinogenesis but suggest that it could be important in the progression from small preneoplastic foci to large tumors.

Topics: Animals; Carcinogens; Cocarcinogenesis; Diethylnitrosamine; Hepatectomy; Humans; Iodine Radioisotopes; Liver Neoplasms, Experimental; Liver Regeneration; Male; Mice; Mice, Inbred C57BL; Precancerous Conditions; Radioimmunoassay; Transforming Growth Factor alpha

We have previously shown that co-expression of c-myc and transforming growth factor (TGF)-alpha as transgenes in mouse liver results in major enhancement of neoplastic development in this organ as compared with expression of either of these transgenes alone. In this report we describe in detail the progression from liver cell dysplasia to hepatocellular carcinomas (HCCs) occurring in the liver of c-myc/TGF-alpha and c-myc transgenic mice. Despite morphological similarities in the sequence of events between the two transgenic lines, the dramatic acceleration, extent, and severity of hepatic lesions in c-myc/TGF-alpha mice clearly demonstrated the synergistic effects of this transgenic combination. Although c-myc/TGF-alpha and c-myc females displayed longer latency and lower tumor incidence, the pathological changes were the same as those seen in the male mice, including the formation of HCCs, which are absent in TGF-alpha single-transgenic females. Tumors in single- and double-transgenic mice showed induction of the endogenous c-myc and TGF-alpha and, most frequently, unchanged or decreased epidermal growth factor receptor, further indicating the collaborative role of c-myc and TGF-alpha in providing a selective growth advantage to tumor cells independently of the epidermal growth factor receptor levels. To identify possible tumor precursors, we focused particularly on the dysplastic changes preceding and accompanying the appearance of preneoplastic and neoplastic lesions in the double-transgenic mice. Early on, these changes were characterized by the appearance of large dysplastic hepatocytes, mostly pericentrally, expressing high levels of TGF-alpha and uPA, as well as TGF-beta 1, particularly in apoptotic cells. After a short period of replication and expansion into the liver parenchyma, as well as penetration into the central veins, these cells underwent apoptotic cell death while preneoplastic and neoplastic lesions were forming. The peritumorous tissues also contained small dysplastic hepatocytes and oval-like cells, similar to those found in the tumors. Transplantation of the transgenic liver tissues harboring only dysplasia with or without vascular lesions onto nude mice was able to yield HCCs composed of small diploid cells, suggesting that initiated cells are generated during the early dysplastic phase and can progress to HCC. It is therefore likely that large dysplastic hepatocytes undergo apoptosis, which may be closely associated with the up-r

Topics: Animals; Apoptosis; Blotting, Northern; Disease Models, Animal; Disease Progression; Female; Gene Expression Regulation, Neoplastic; Immunohistochemistry; Incidence; Liver; Liver Neoplasms; Liver Transplantation; Male; Mice; Mice, Transgenic; Organ Size; Phenotype; Precancerous Conditions; Proto-Oncogene Proteins c-myc; Transforming Growth Factor alpha

We previously reported the induction of dysplasia, a putative precursor of carcinoma, in the dorsolateral prostates (DLPs) of Noble rats by the combined administration of testosterone (T) and estradiol-17beta (E2) for 16 weeks. Additionally, we demonstrated growth of the AIT, a DLP-derived, androgen-independent, transplantable solid tumor, in castrated syngeneic hosts. In this investigation, using Northern blot hybridization, radioimmunoassays and radioligand assays, we showed that transforming growth factor-alpha (TGFalpha) and epidermal growth factor receptor (EGFR) were expressed at close to non-detectable levels in the ventral prostates but at low, but measurable, levels in the DLPs of untreated rats. Enhanced expression of this ligand and its receptor was detected in the DLPs harboring dysplasia and marked overexpression of these molecules was noted in the AIT. In contrast, epidermal growth factor (EGF) expression was found to be constitutively expressed, at high levels, in both normal and dysplastic DLPs, but virtually absent in the AIT. Immunohistochemical data suggested that EGF, TGFalpha and EGFR were aprocine secretory products of the normal DLP, with TGFalpha and EGF localized to the supranuclear complexes and EGFR to the apical membranes of epithelial cells. Alterations in immunostaining patterns for TGFalpha and EGFR were exclusively detected in the dysplastic lesions in the DLPs of T + E2-treated rats. Enhanced intracytoplasmic localization for both peptides were found to accompany the loss of cell polarity in dysplastic foci. Strong intracytoplasmic immunostaining for TGFalpha was observed in some AIT cells whilst staining for EGFR was present in the membranes of tumor cells that formed psuedoacini. Taken together, our findings suggest that autocrine mechanisms may play an important role early in the carcinogenic process and that progression to an androgen-independent neoplastic growth may be modulated by this signaling pathway.

Topics: Animals; ErbB Receptors; Gonadal Steroid Hormones; Male; Precancerous Conditions; Prostatic Neoplasms; Rats; 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

Transforming growth factor (TGF)-alpha stimulates the growth and development of mammary epithelial cells and is implicated in the pathogenesis of human breast cancer. In this report we evaluate the consequences of overexpressing TGF-alpha in the mammary gland of transgenic mice and examine associated cellular mechanisms. When operating on a FVB/N genetic background (line MT100), TGF-alpha induced the stochastic development of mammary adenomas and adenocarcinomas f secretory epithelial origin in 64% of multiparous females. In contrast, tumors were exceedingly rare in virgin MT100 females, MT100 males, and multiparous FVB/N females. In MT100 females multiple foci of hyperplastic secretory lesions preceded the development of frank tumors; these initial lesions appeared during the involution period after the first lactation. Serial transplantation of these hyperplasias indicated an absence of proliferative immortality. Nevertheless, they gave rise to tumors at a low frequency and after a prolonged latency in virgin hosts; in multiparous hosts, tumors developed earlier and at a high incidence. The TGF-alpha transgene was highly expressed in hyperplasias and tumors but not in virgin and nonlesion-bearing tissue, suggesting that TGF-alpha overexpression provides a selective growth advantage. TGF-alpha also induced at lactation a 6.4-fold increase in DNA synthesis in MT100 epithelial cells, many of which were binucleated. MT100 mammary tissue experienced an obvious delay in involution, resulting in the postlactational survival of a significant population of unregressed secretory epithelial cells. In contrast, another line of transgenic mice on a CD-1 genetic background (MT42), in which TGF-alpha overexpression induced liver but not mammary tumors, failed to demonstrate postlactational epithelial cell survival. These data show that TGF-alpha promotes mammary tumorigenesis in multiparous MT100 mice by stimulating secretory epithelial cell proliferation during lactation and prolonging survival during involution. These points support the notion that TGF-alpha can act as a mitogen and also as a differentiation factor in mammary epithelium.

Topics: Adenocarcinoma; Adenoma; Animals; Cell Division; Cell Line; Cell Survival; Epithelium; Female; Gene Expression; Humans; Hyperplasia; Mammary Glands, Animal; Mammary Neoplasms, Animal; Mice; Mice, Transgenic; Precancerous Conditions; Tissue Transplantation; Transforming Growth Factor alpha

Glandular stomach carcinogenesis after N-nitrosomethylurea (NMU) treatment was examined in transgenic mice bearing a human transforming growth factor alpha (TGF-alpha) cDNA driven by the mouse metallothionein-I promoter (mouse line MT100) in the inbred mouse line FVB/N. Untreated MT100 mice exhibit a severe age-related gastric fundic hyperplasia. Both sexes of MT100 mice were given 10 weekly intragastric intubations of 0.5 mg NMU per mouse from 6 weeks of age and/or zinc chloride in drinking water to stimulate transgene expression from 5.5 weeks of age to the experiment termination. Animals were killed sequentially at 10, 19 and 29 experimental weeks. Several histochemical markers (AB-PAS, TGF-alpha, pepsinogen isozyme 1, proliferating cell nuclear antigen) were used. Abnormal histochemical patterns were found in untreated MT100 and NMU-treated MT100 mice for all 4 markers of differentiation and carcinogenesis. Precancerous lesions including atypical and/or adenomatous hyperplasia were found in the fundic region of 16/22 male and 8/22 female MT100 mice but not in 27 male and 24 female FVB/N mice treated with NMU. One of 22 MT100 males had fundic carcinoma. FVB/N mice treated with NMU had neither precancerous lesions nor carcinomas in the fundus. Well differentiated adenocarcinomas in the pyloric region were induced at incidences of 2/22 male and 1/22 female MT100 mice treated with NMU and 4/27 male and 4/24 female FVB/N mice treated with NMU. Both strains also had a high incidence (55 to 92%) of squamous cell carcinomas of the forestomach. In conclusion, TGF-alpha induced a hyperplastic lesion in the gastric fundus that appeared to predispose the MT100 mice to carcinogenesis by NMU.

Topics: Adenocarcinoma; Animals; Female; Hyperplasia; Immunohistochemistry; Male; Methylnitrosourea; Mice; Mice, Transgenic; Pepsinogens; Precancerous Conditions; Stomach; Stomach Neoplasms; Transforming Growth Factor alpha

Epidermal growth factor (EGF), its related peptide transforming growth factor (TGF-alpha) and their common receptor (EGFR) have been implicated in the control of cell proliferation and differentiation in the gastrointestinal epithelium and may play an important role in gastric carcinogenesis. We compared the immunohistochemical expression and topographic distribution of these peptides using Western blot analysis in gastric carcinoma precursor lesions and in non-cancer tissue. We observed: (i) increased and extended expression of TGF-alpha in normal mucosa and hyperplasia in carcinoma fields compared with non-cancer controls; (ii) increased expression of EGFR in intestinal metaplasia (IM) from carcinoma fields compared with controls; (iii) EGF expression was not detected in normal mucosa and only weakly in IM; (iv) coexpression of TGF-alpha/EGFR and EGF/EGFR was higher in intestinal metaplasia in carcinoma fields than in non-cancer controls. We conclude that altered expression of TGF-alpha/EGFR is associated with morphological changes during gastric carcinogenesis. In this regard increased expression of TGF-alpha is a very early event which is subsequently followed by up-regulation of EGFR and this has important biological and clinical implications.

Topics: Epidermal Growth Factor; ErbB Receptors; Humans; Immunohistochemistry; Precancerous Conditions; Stomach Neoplasms; Transforming Growth Factor alpha

In order to more clearly define the status of epidermal growth factor receptor (EGFR) in prostate cancer, expression of EGFR transcript and protein was analyzed in paired samples of benign and malignant tissues from 30 radical prostatectomy specimens. Prostate tumors and high grade prostatic intraepithelial neoplasias (PINs) expressed significantly less EGFR protein than benign tissues or low grade PINs (P < 0.001). Expression of EGFR mRNA was analyzed in a subset of the same samples, and was higher in more prostate tumors than benign specimens (P < 0.05). However, differences in mean mRNA expression between malignant and benign tissues were not significant. EGFR mRNA was expressed at moderate or low levels in equivalent numbers of PIN lesions. These results suggest that, although EGFR mRNA expression is somewhat elevated in prostate tumors, EGFR protein expression may be down-regulated in the same malignant tissues. Furthermore, our data demonstrate phenotypic similarity between prostate tumors and high grade PIN at the level of EGFR protein expression.

Topics: Aged; Atrophy; Carcinoma in Situ; Epidermal Growth Factor; ErbB Receptors; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; In Situ Hybridization; Male; Middle Aged; Precancerous Conditions; Prostate; Prostatic Hyperplasia; Prostatic Neoplasms; RNA, Messenger; Transforming Growth Factor alpha

Immunohistochemical examination of radical prostatectomy specimens from 57 patients was performed to determine the differential expression of transforming growth factor alpha in the human prostate. In addition, epidermal growth factor receptor (EGFr) immunoreactivity was assessed in each case. Stromal versus epithelial staining was determined for each histological subtype: benign prostatic hypertrophy (BPH), prostatic intra-epithelial neoplasia (PIN), and prostatic cancer (CaP) by a single pathologist reviewer. TGFa staining was predominant in stroma while EGFr was localized to the epithelial basal cell layer. Immunoreactivity of both TGFa (P = 0.002) and EGFr (P < 0.001) revealed a significant reduction in CaP compared to BPH or PIN. Autocrine stimulation of EGFr by TGFa or other unrecognized factors may be present in CaP. Conversely, altered stromal influence of CaP via TGFa may be present. These observations could form the basis for future cancer therapeutic strategies using antagonist factors.

Topics: Aged; ErbB Receptors; Humans; Immunohistochemistry; Male; Middle Aged; Precancerous Conditions; Prostatic Hyperplasia; Prostatic Neoplasms; Transforming Growth Factor alpha

Expression of transforming growth factor alpha (TGF alpha) was investigated immunohistochemically in preneoplastic and neoplastic hepatocytes induced by the Solt-Farber regimen. Although TGF alpha was almost negative in early lesions comparing carcinogen-altered hepatocytes, it was expressed in approximately 65% of the late lesions. Growth factor localization was predominantly in the cytoplasm or at the bile canalicular membrane within individual lesions, both types being observed at various ratios. Hyperplastic nodules (HPN) predominantly consisting of cells with cytoplasmic type staining showed expansive growth with more abundant expression of EGF receptors (EGFR) and proliferating cell nuclear antigen (PCNA) than those with the membranous localization. The staining patterns of TGF alpha, EGFR and PCNA in hepatocellular carcinomas (HCC) were similar to those of cytoplasmic type growth factor-positive HPN. Western blotting analysis for TGF alpha demonstrated a single 30 kDa protein in lysates of HPN and HCC. Since this protein was broken down to the 6 kDa mature TGF alpha via 20, 16 and 14 kDa forms by treatment with bovine pancreatic elastase, it may represent a physiological precursor. No mature TGF alpha was detected in the conditioned medium of cultured HPN cells, although a small amount of the 30 kDa form was identified. These results suggest that this form of TGF alpha may have an important role in the growth of preneoplastic and neoplastic hepatocytes during rat hepatocarcinogenesis.

Topics: Animals; Cell Division; ErbB Receptors; Liver Neoplasms, Experimental; Male; Molecular Weight; Nuclear Proteins; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Protein Precursors; Rats; Rats, Inbred F344; Transforming Growth Factor alpha; Tumor Cells, Cultured

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

The induction of adenocarcinomas in the glandular stomach of the adult male Wistar rat by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was used as a model to study the expression of the growth promoting peptide, transforming growth factor alpha (TGF alpha), during experimental gastric carcinogenesis. TGF alpha was identified using the monoclonal antibody Ab-2 and standard immunohistochemistry, together with a semiquantitative assessment of the intensity of expression. Immunoreactivity was confined to the differentiated compartment of the mucosa while the carcinogen MNNG caused a significant increase in the intensity of TGF alpha expression (p < 0.01), after as little as 16 weeks' exposure. In experimental adenocarcinomas, a change to a previously undescribed pattern of perinuclear TGF alpha expression was found, which may represent the site of intense TGF alpha production in the Golgi apparatus after malignant transformation.

Topics: Adenocarcinoma; Animals; Immunohistochemistry; Intestinal Mucosa; Male; Methylnitronitrosoguanidine; Precancerous Conditions; Rats; Rats, Wistar; Stomach Neoplasms; Transforming Growth Factor alpha

A recent study from our laboratory demonstrated that cyclosporine (CsA), a prototype immunosuppressant, enhanced the growth of carcinogen-induced enzyme altered foci in rat liver, suggesting that CsA may stimulate development of hepatocellular carcinomas. In the present study, we examined (i) whether CsA accelerates development of hepatocellular carcinomas in experimental animals, (ii) whether CsA stimulates the proliferation of resting hepatocyte in vivo and (iii) whether CsA modulates the production of growth factors implicated in liver cell growth, hepatocyte growth factor (HGF), transforming growth factor alpha (TGF alpha) and transforming growth factor beta 1 (TGF beta 1). Foci of hepatocytes, positive for glutathione S-transferase placental form were induced in male F344 rats by a single dose of diethylnitrosamine followed by 7 weeks promotion by a choline-deficient diet. The animals were then divided in two groups, and subsequent development of hepatocellular carcinomas was compared in rats fed a basal diet or a basal diet containing 0.015% CsA. Development of hepatocellular carcinoma was accelerated in the rats maintained on a CsA diet. Feeding a CsA diet as the sole treatment, for 2, 4 and 10 weeks induced significant increases in liver weight, and resulted also in an enhanced incorporation by hepatocytes of 5-bromo-2-deoxy-uridine. Serum levels of glutamate-oxaloacetate transferase, glutamate-pyruvate transferase and lactic dehydrogenase were not altered by feeding a CsA diet. Northern Blot analyses of the expression of HGF, TGF alpha and TGF beta 1 mRNAs in the liver showed similar patterns of expression between rats fed a basal diet and a CsA diet. The levels of HGF mRNA were not altered in the lungs and kidneys of rats fed a CsA diet. These results indicate that CsA stimulates rat liver cell proliferation in vivo without inducing liver cell necrosis, and that this effect may contribute to accelerated development of hepatocellular carcinomas in rats fed a CsA diet. As previously observed with BR 931, a hypolipidemic peroxisome proliferator, stimulation of liver cell growth by CsA did not entail changes in the production of HGF, TGF alpha or TGF beta 1.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Base Sequence; Cell Division; Cyclosporine; Hepatocyte Growth Factor; Kidney; L-Lactate Dehydrogenase; Liver; Liver Neoplasms, Experimental; Liver Regeneration; Lung; Male; Molecular Sequence Data; Organ Size; Precancerous Conditions; Rats; Rats, Inbred F344; RNA, Messenger; Stimulation, Chemical; Transforming Growth Factor alpha; Transforming Growth Factor beta

To determine at what stage there is increased expression of transforming growth factor alpha (TGF alpha) in preneoplastic diseases of the breast and to determine if this would assist in the histological diagnosis of different intraduct epithelial proliferations.. Specimens were retrieved from the archives of 17 cases of ductal hyperplasia, six cases of atypical ductal hyperplasia and 13 cases of ductal carcinoma in situ together with 12 'normal' breast biopsy specimens. Sections were stained immunohistochemically for TGF alpha. The staining was assessed semi-quantitatively taking into account both the staining intensity and the proportion of cells stained.. Minimal expression of TGF alpha was observed in normal breast tissue. Increased levels of expression were seen in ductal hyperplasia, atypical ductal hyperplasia, and ductal carcinoma in situ. Increased levels of expression of TGF alpha were also found in morphologically normal ducts immediately adjacent to areas of intraduct epithelial proliferation.. Increased expression of TGF alpha occurs in the early stages of intraduct epithelial proliferation and will not help the histopathologist distinguish atypical ductal hyperplasia from either ductal hyperplasia or ductal carcinoma in situ. The molecular changes within a cell may precede the morphological changes observed by light microscopy thereby reflecting the biological potential of the epithelium.

Topics: Adult; Aged; Breast; Breast Neoplasms; Carcinoma in Situ; Carcinoma, Intraductal, Noninfiltrating; Female; Humans; Hyperplasia; Middle Aged; Precancerous Conditions; Transforming Growth Factor alpha

This study was designed to correlate mucosal proliferation in Barrett's oesophagus with expression of a growth promoting peptide, transforming growth factor alpha (TGF alpha). Oesophageal mucosa was studied from 50 patients with oesophageal disease who had been treated by oesophagectomy. Histological analysis showed a range of oesophageal pathology - 18 patients had gastric type Barrett's mucosa, 18 had intestinal type Barrett's mucosa, and 14 had oesophageal adenocarcinomas. Sections were stained immunohistochemically for proliferating cell nuclear antigen (PCNA) (an index of cellular proliferation) and TGF alpha. PCNA immunostaining was seen mainly in the basal cells of the neck/foveolar epithelial compartment of the glands in Barrett's oesophagus. However, in mucosa with high grade dysplasia, the proliferative compartment extended upwards into the superficial layers of the glands. At least 2000 cells were counted in each patient to determine the proportion with PCNA immunoreactivity (PCNA labelling index). The labelling index was highest in adenocarcinoma (25%) and in Barrett's intestinal type mucosa with high grade dysplasia (26%) compared with intestinal type mucosa with no significant dysplasia (20%) and Barrett's gastric type mucosa (12%). There was a significant positive correlation between PCNA labelling indices and TGF alpha expression in Barrett's mucosa (p less than 0.01). In glands showing high grade dysplasia, TGF alpha immunoreactivity was seen in the same regions of the glands as PCNA immunoreactivity, indicating the possibility of involvement of TGF alpha in (pre) neoplastic proliferation in Barrett's oesophagus.

Topics: Adenocarcinoma; Autoantigens; Barrett Esophagus; Cell Count; Esophageal Neoplasms; Esophagus; Humans; Mitosis; Nuclear Proteins; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Transforming Growth Factor alpha

Growth factors in general and transforming growth factor-alpha in particular have been related to cell proliferation and cell differentiation. This study was designed to clarify the distribution pattern of TGF-alpha in chemically-induced hepatocarcinogenesis. Sprague-Dawley rats were subjected to different non-intensive or intensive carcinogenic treatments using diethylnitrosamine (DEN) as carcinogen and ethinyl estradiol (EE) as promoter. The livers were fixed in 2% paraformaldehyde, dehydrated in a series of ethanol solutions, embedded in paraffin and sectioned. In the preneoplastic lesions no TGF-alpha immunoreactive cells were identified, but in some hepatic tumours cell immunostained with TGF-alpha antibody were observed. These results suggest that the cells capable of expressing TGF-alpha constitutively may be involved in neoplastic development in vivo.

Topics: Animals; Diethylnitrosamine; Ethinyl Estradiol; Female; Immunohistochemistry; Liver Neoplasms, Experimental; Male; Precancerous Conditions; Rats; Rats, Inbred Strains; Transforming Growth Factor alpha