epidermal-growth-factor and Precancerous-Conditions

During tumor progression, malignant cells exploit critical developmental and tissue remodeling programs, often promoting a plastic phenotype referred to as an epithelial-mesenchymal transition (EMT). Autocrine/paracrine signaling due to tumor microenvironment cytokines, such as members of the transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF) families, largely regulates the morphological and invasive phases of the EMT phenotype. Notably, epithelial cell initiation often coincides with a switch in the response of these cells to TGF-beta and is concomitant with EGF receptor amplification. Modeling these events, we have observed that premalignant human keratinocytes, HaCaTs, acquire a highly motile and scattered phenotype indicative of EMT following stimulation with TGF-beta1 and EGF. TGF-beta1 and EGF have been shown to upregulate a number of matrix metalloproteinases (MMP) in epithelial cells, which may in turn play a role in developing metastatic potential in these cells. We have established that an increase in MMP-10 expression occurs following treatment of HaCaT cells with a combination of TGF-beta1 and EGF. This increase in MMP-10 expression paralleled the development of a collagenolytic phenotype that was sensitive to components of the plasminogen activation system, including the plasminogen activator inhibitor type-1 (PAI-1). Significantly high levels of MMP-10 have been detected in squamous cell carcinomas of the head and neck, esophagus, oral cavity and skin. Importantly, TGF-beta1 in addition to upregulating MMP-10 has been shown to upregulate PAI-1 expression in HaCaT cells. Taken together, these observations suggest that TGF-beta1 and EGF play a complex role in modulating proteolytic and transitional events such as EMT that may facilitate the progression of human premalignant epithelial cells toward a more invasive phenotype.

Topics: Epidermal Growth Factor; Epithelial Cells; Epithelium; Extracellular Matrix; Humans; Keratinocytes; Mesoderm; Models, Biological; Precancerous Conditions; Transforming Growth Factor beta1

Barrett's esophagus is an acquired metaplastic change that occurs in the distal esophagus secondary to chronic gastroesophageal reflux. This premalignant condition forms the most important risk factor for developing esophageal adenocarcinoma, which is an extremely aggressive tumor with a 5-year survival rate of less than 25%. Carcinomas that arise in the setting of Barrett's esophagus are thought to develop as part of the metaplasia-dysplasia-carcinoma sequence.. To review the current knowledge on the genomic alterations involved in the development of Barrett's esophagus and its progression to dysplasia and/or cancer.. Several changes in gene structure, gene expression, and protein structure are associated with the progression of Barrett's esophagus to adenocarcinoma. Accumulation of these changes seems to be essential, rather than the exact sequence of these changes. Multiple molecular pathways are involved and interact with each other. Alterations in tumor suppressor genes, amongst which p53 and p16, are early events in the metaplasia-dysplasia-adenocarcinoma sequence, followed by loss of cell cycle checkpoints. Ongoing genomic instability leads to cumulative genetic errors and thereby the generation of multiple clones of transformed cells.. Within the multistep process of esophageal adenocarcinogenesis, to date no single molecular marker came forward able to predict who will and who will not develop cancer in the setting of Barrett's esophagus. Instead, panels of markers need to be developed in the future allowing to indicate disease progression. Identification of crucial molecular pathways involved in esophageal adenocarcinogenesis would ultimately improve therapy and facilitate development of new treatment strategies.

Topics: Adenocarcinoma; Apoptosis; Barrett Esophagus; Chromosome Aberrations; Cyclin D1; DNA, Neoplasm; Epidermal Growth Factor; ErbB Receptors; Esophageal Neoplasms; Gastroesophageal Reflux; Gene Expression Regulation, Neoplastic; Humans; Metaplasia; Microsatellite Repeats; Precancerous Conditions; Receptor, ErbB-2; Tumor Suppressor Protein p53

The aims of chemoprevention in lung cancer are to prevent the appearance of disease (primary prevention) and to stop or reverse the progression of premalignant lesions (secondary prevention). Until recently, there was little hope that these goals could be attained. However, the results achieved with tamoxifen in the prevention of breast cancer, and the emergence of new therapies specifically targeted to molecules involved in the pathogenesis of lung cancer have set the stage for investigation of these agents for chemoprevention of lung cancer. Two of these new molecular targeted agents are gefitinib, an inhibitor of epidermal growth factor receptor-tyrosine kinase activity, and tipifarnib (R115777, Zarnestra ), an inhibitor of the farnesyltransferase enzyme, which is required for the proper localization and function of the ras oncogene. Tumor responses and disease stabilization have been achieved with both agents in clinical trials. In the Iressa Dose Evaluation in Advanced Lung Cancer (IDEAL)-1 and IDEAL-2 phase II trials, gefitinib was demonstrated to be effective for disease control in patients with advanced non-small-cell lung cancer. The SPORE (Specialized Program of Research Excellence) Trials of Lung Cancer Prevention (STOP) are 2 parallel studies that will investigate the potential effectiveness of gefitinib and tipifarnib in preventing the appearance and progression of premalignant lesions in former or current smokers with a history of smoking-related cancer. These trials should provide information not only about the potential role of gefitinib and tipifarnib in lung cancer chemoprevention, but also about the molecular changes that underlie tumorigenesis and that may serve as markers of disease progression. The STOP trial objectives are to evaluate the effect of gefitinib and tipifarnib on histologic and biologic parameters in patients with evidence of sputum atypia, to evaluate various parameters as potential predictors of the effectiveness of these agents, and to evaluate the tolerability of these agents over a 6-month course of treatment. Histologic response, defined as prevention of appearance or progression of premalignant lesions, is the primary endpoint of these trials. New targeted molecular therapies such as gefitinib and tipifarnib may offer the opportunity to make chemoprevention a viable treatment modality in lung cancer as well as in other human solid tumors.

Topics: Antineoplastic Agents; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Chemoprevention; Clinical Trials as Topic; Disease Progression; Epidermal Growth Factor; Gefitinib; Humans; Lung Neoplasms; Precancerous Conditions; Protein-Tyrosine Kinases; Quinazolines; Quinolones

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

Prostatic cancer is the second most frequent cancer in men in industrialised countries. The histological analysis of its initial development demonstrates the existence of precancerous lesions, PIN. The initial presence of several different cell populations accounts for the development of contingents of hormone-sensitive and hormone-resistant cells. The presence of numerous neuroendocrine cells appears to be a factor of poor prognosis. Hormones are intimately involved in the development of prostatic cancer and are an integral part of its treatment. Progress in molecular biology has furthered out knowledge of this disease. In particular, growth factors such as EGF and FGF are particularly involved and are starting to have a clinical application. The oncogene and anti-oncogene system is currently being explored (particularly p53 abd BCL 2). They are the basis for carcinogenesis and analysis of these factors will allow a better approach to the mechanisms of tumour induction and development.

Topics: Androgens; Epidermal Growth Factor; Fibroblast Growth Factors; Humans; Male; Neurosecretory Systems; Oncogenes; Precancerous Conditions; Prostatic Neoplasms

To review genetic alterations in precancerous lesions and adenocarcinoma of the stomach.. Telomere reduction, tpr-met oncogenic rearrangement, overexpression of cripto, p53 mutations, adenomatous polyposis coli gene mutations and K-ras mutations, which are frequently associated with the well differentiated or intestinal type of stomach cancer, were found in intestinal metaplasia and adenoma of the stomach.. Among these genetic alterations, reduction of telomere repeat arrays might be the initial step in the genetic instability of stomach carcinogenesis. Some of the well differentiated type stomach cancers may develop by an accumulation of multiple gene changes similar to those of colorectal cancer.

Topics: Base Sequence; Biomarkers, Tumor; Epidermal Growth Factor; Gene Expression; Genes, Tumor Suppressor; GPI-Linked Proteins; Humans; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Intestines; Membrane Glycoproteins; Metaplasia; Molecular Sequence Data; Neoplasm Proteins; Oncogenes; Precancerous Conditions; Stomach Neoplasms; Telomere

Topics: Chromosome Aberrations; Chromosome Disorders; DNA, Neoplasm; Epidermal Growth Factor; Genes, ras; Genes, Retinoblastoma; Genes, src; Heterozygote; Humans; In Situ Hybridization, Fluorescence; Karyotyping; Oncogene Proteins, Viral; Oncogenes; Precancerous Conditions; Receptor, ErbB-2; Urinary Bladder Neoplasms

Topics: Adenoma; Animals; Cell Division; Cell Line; Cells, Cultured; Colonic Neoplasms; Culture Techniques; Deoxycholic Acid; Epidermal Growth Factor; Humans; Models, Biological; Plasminogen Activators; Precancerous Conditions; Tetradecanoylphorbol Acetate

Thoracic pair of mammary glands from steroid hormone-pretreated mice respond to hormones structurally and functionally in organ culture. A short exposure of glands for 24 h to 7,12 Dimethylbenz(a)anthracene (DMBA) during a 24-day culture period induced alveolar or ductal lesions. Methods: To differentiate the functional significance of ERα and ERβ, we employed estrogen receptor (ER) knockout mice. We compared the effects of DMBA on the development of preneoplastic lesions in the glands in the absence of ERα (αERKO) and ERβ (βERKO) using an MMOC protocol. Glands were also subjected to microarray analyses. We showed that estradiol can be replaced by EGF for pretreatment of mice. The carcinogen-induced lesions developed under both steroids and EGF pretreatment protocols. The glands from αERKO did not develop any lesions, whereas in βERKO mice in which ERα is intact, mammary alveolar lesions developed. Comparison of microarrays of control, αERKO and βERKO mice showed that ERα was largely responsible for proliferation and the MAP kinase pathways, whereas ERβ regulated steroid metabolism-related genes. The results indicate that ERα is essential for the development of precancerous lesions. Both subtypes, ERα and Erβ, differentially regulated gene expression in mammary glands in organ cultures.

Topics: Animals; Anthracenes; Epidermal Growth Factor; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Mammary Glands, Animal; Mice; Mice, Knockout; Oligonucleotide Array Sequence Analysis; Organ Culture Techniques; Piperidines; Precancerous Conditions; Signal Transduction

Atypical adenomatous hyperplasia (AAH) of the lung is a pre-invasive lesion (PL) with high risk of progression to lung cancer (LC). However, the pathways involved are uncertain. We searched for novel mechanistic biomarkers of AAH in an EGF transgenic disease model of lung cancer. Disease regulated proteins were validated by Western immunoblotting and immunohistochemistry (IHC) of control and morphologically altered respiratory epithelium. Translational work involved clinical resection material. Collectively, 68 unique serum proteins were identified by 2DE-MALDI-TOF mass spectrometry and 13 reached statistical significance (p < 0.05). EGF, amphiregulin and the EGFR endosomal sorting protein VPS28 were induced up to 5-fold while IHC confirmed strong induction of these proteins. Furthermore, ApoA1, α-2-macroglobulin, and vitamin-D binding protein were nearly 6- and 2-fold upregulated in AAH; however, ApoA1 was oppositely regulated in LC to evidence disease stage dependent regulation of this tumour suppressor. Conversely, plasminogen and transthyretin were highly significantly repressed by 3- and 20-fold. IHC confirmed induced ApoA1, Fetuin-B and transthyretin expression to influence calcification, inflammation and tumour-infiltrating macrophages. Moreover, serum ApoA4, ApoH and ApoM were 2-, 2- and 6-fold repressed; however tissue ApoM and sphingosine-1-phosphate receptor expression was markedly induced to suggest a critical role of sphingosine-1-phosphate signalling in PL and malignant transformation. Finally, a comparison of three different LC models revealed common and unique serum biomarkers mechanistically linked to EGFR, cMyc and cRaf signalling. Their validation by IHC on clinical resection material established relevance for distinct human lung pathologies. In conclusion, we identified mechanistic biomarker candidates recommended for in-depth clinical evaluation.

Topics: Amphiregulin; Animals; Biomarkers, Tumor; Disease Models, Animal; Endosomal Sorting Complexes Required for Transport; Epidermal Growth Factor; Humans; Hyperplasia; Lung; Mice; Mice, Transgenic; Precancerous Conditions; Proteomics; Signal Transduction; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Up-Regulation

The development of pancreatic cancer requires the acquisition of oncogenic KRas mutations and upregulation of growth factor signaling, but the relationship between these is not well established. Here, we show that mutant KRas alters mitochondrial metabolism in pancreatic acinar cells, resulting in increased generation of mitochondrial reactive oxygen species (mROS). Mitochondrial ROS then drives the dedifferentiation of acinar cells to a duct-like progenitor phenotype and progression to PanIN. This is mediated via the ROS-receptive kinase protein kinase D1 and the transcription factors NF-κB1 and NF-κB2, which upregulate expression of the epidermal growth factor, its ligands, and their sheddase ADAM17. In vivo, interception of KRas-mediated generation of mROS reduced the formation of pre-neoplastic lesions. Hence, our data provide insight into how oncogenic KRas interacts with growth factor signaling to induce the formation of pancreatic cancer.

Topics: Acinar Cells; ADAM17 Protein; Animals; Cells, Cultured; Epidermal Growth Factor; ErbB Receptors; Humans; Ligands; Mice; Mitochondria; Mutagenesis, Site-Directed; NF-kappa B p52 Subunit; Oxidative Stress; Pancreatic Neoplasms; Precancerous Conditions; Protein Kinase C; Proto-Oncogene Proteins p21(ras); Reactive Oxygen Species; RNA Interference; Signal Transduction; Up-Regulation

The assessment of cancer risk in patients with Barrett's esophagus (BE) is currently fraught with difficulty. The current gold standard method of assessing cancer risk is histological assessment, with the appearance of high-grade dysplasia (HGD) as the key event monitored. Sampling error during endoscopy limits the usefulness of this approach, and there has been much recent interest in supplementing histological assessment with molecular markers, which may aid in patient stratification.. No molecular marker has been yet validated to accurately correlate with esophageal histological progression. Here, we assessed the suitability of several membranous proteins as biomarkers by correlating their abundance with histological progression. In all, 107 patient samples, from 100 patients, were arranged on a tissue microarray (TMA) and represented the various stages of histological progression in BE. This TMA was probed with antibodies for eight receptor proteins (mostly membranous).. Epidermal growth factor receptor (EGFR) staining was found to be the most promising biomarker identified with clear increases in staining accompanying histological progression. Further, immunohistochemistry was performed using the full-tissue sections from BE, HGD, and adenocarcinoma tissues, which confirmed the stepwise increase in EGFR abundance. Using a robust H-score analysis, EGFR abundance was shown to increase 13-fold in the adenocarcinoma tissues compared to the BE tissues. EGFR was "overexpressed" in 35% of HGD specimens and 80% of adenocarcinoma specimens when using the H-score of the BE patients (plus 3 s.d.) as the threshold to define overexpression. EGFR staining was also noted to be higher in BE tissues adjacent to HGD/adenocarcinoma. Western blotting, although showing more EGFR protein in the adenocarcinomas compared to the BE tissue, was highly variable. EGFR overexpression was accompanied by aneuploidy (gain) of chromosome 7, plus amplification of the EGFR locus. Finally, the bile acid deoxycholic acid (DCA) (at neutral and acidic pH) and acid alone was capable of upregulating EGFR mRNA in vitro, and in the case of neutral pH DCA, this was NF-κB dependent.. EGFR is overexpressed during the histological progression in BE tissues and hence may be useful as a biomarker of histological progression. Furthermore, as EGFR is a membranous protein expressed on the luminal surface of the esophageal mucosa, it may also be a useful target for biopsy guidance during endoscopy.

Topics: Adenocarcinoma; Aged; Barrett Esophagus; Biomarkers, Tumor; Biopsy, Needle; Blotting, Western; Cell Transformation, Neoplastic; Cohort Studies; Disease Progression; Epidermal Growth Factor; Esophageal Neoplasms; Female; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Male; Middle Aged; Neoplasm Staging; Polymerase Chain Reaction; Precancerous Conditions; Predictive Value of Tests; Prognosis; RNA, Messenger; Up-Regulation

The molecular causes by which the epidermal growth factor receptor tyrosine kinase induces malignant transformation are largely unknown. To better understand EGFs' transforming capacity whole genome scans were applied to a transgenic mouse model of liver cancer and subjected to advanced methods of computational analysis to construct de novo gene regulatory networks based on a combination of sequence analysis and entrained graph-topological algorithms. Here we identified transcription factors, processes, key nodes and molecules to connect as yet unknown interacting partners at the level of protein-DNA interaction. Many of those could be confirmed by electromobility band shift assay at recognition sites of gene specific promoters and by western blotting of nuclear proteins. A novel cellular regulatory circuitry could therefore be proposed that connects cell cycle regulated genes with components of the EGF signaling pathway. Promoter analysis of differentially expressed genes suggested the majority of regulated transcription factors to display specificity to either the pre-tumor or the tumor state. Subsequent search for signal transduction key nodes upstream of the identified transcription factors and their targets suggested the insulin-like growth factor pathway to render the tumor cells independent of EGF receptor activity. Notably, expression of IGF2 in addition to many components of this pathway was highly upregulated in tumors. Together, we propose a switch in autocrine signaling to foster tumor growth that was initially triggered by EGF and demonstrate the knowledge gain form promoter analysis combined with upstream key node identification.

Topics: Animals; Binding Sites; Biomarkers, Tumor; Cell Cycle; Cluster Analysis; Computational Biology; Disease Models, Animal; DNA, Neoplasm; Down-Regulation; Epidermal Growth Factor; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Regulatory Networks; Genes, Neoplasm; Lipid Metabolism; Liver Neoplasms; Mice; Mice, Transgenic; Precancerous Conditions; Promoter Regions, Genetic; Protein Binding; Signal Transduction; Transcription Factors; Up-Regulation

To explore the relationship between Cripto-1 (CR-1) and tyrosine phosphorylation STAT3 (p-STAT3) expressions in gastric cancer (GC) and gastric carcinogensis and metastasis.. The PV9000 immunohistochemical method was used to detect the expression of CR-1 and p-STAT3 in 178 cases of GC, 95 matched normal gastric mucosa, 40 chronic atrophic gastritis (CAG), 48 intestinal metaplasia (IM) and 25 dysplasia (DYS).. The positive rates of CR-1 and p-STAT3 expression were significantly higher in CAG (65.0% and 60.0%), in IM (83.3% and 77.1%), DYS (80.0% and 68%) and GC (71.3% and 60.1%) than in normal gastric mucosa (43.2% and 41.1%, P < 0.05), respectively. The expressions of CR-1 and p-STAT3 (78.3% and 66.7%) were significantly higher in GC with lymph node metastasis than in those without metastasis (53.1% and 42.9%, P < 0.05). CR-1 expression was also related to histological and Lauren's types of GC (P < 0.001). Furthermore, there was positive relationship between CR-1 and p-STAT3 expressions in GC (r(k) = 0.189, P = 0.002).. The up-regulation of CR-1 and p-STAT3 may play important roles in gastric carcinogenesis and lymph node metastasis. CR-1 and p-STAT3 expression in GC was positively correlated, and the relevant molecular mechanism requires further investigations.

Topics: Animals; Epidermal Growth Factor; Female; Gastric Mucosa; GPI-Linked Proteins; Humans; Intercellular Signaling Peptides and Proteins; Lymphatic Metastasis; Male; Membrane Glycoproteins; Middle Aged; Neoplasm Proteins; Precancerous Conditions; STAT3 Transcription Factor; Stomach Neoplasms; Tissue Array Analysis

Amphiregulin (AREG) and epiregulin (EREG) have been found to play pivotal roles in several malignancies. However, the correlation between their expression and clinicopathological factors in colorectal carcinoma (CRC) is yet to be further investigated. To clarify the clinical significance of AREG and EREG expression in CRC, we detected serum and tissue levels of AREG and EREG.. We detected serum AREG and EREG levels by ELISA, and tissue levels by immunohistochemical test in 73 patients with CRC. The correlation between each independent clinicopathological characteristic and AREG and EREG levels was examined.. There was significant correlation between serum AREG level and vascular invasion. There was no correlation between EREG serum level and any clinicopathological characteristics. Among the 73 primary lesions, 51 were AREG-positive, and 48 were EREG-positive. AREG-positive status was significantly correlated with depth of tumor invasion, distant metastases, and nerve invasion. EREG-positive status was significantly correlated with depth of tumor invasion and distant metastases. Coexpression analysis showed that 46 patients were both AREG-positive and EREG-positive.. High serum and tissue levels of AREG and high tissue level of EREG are predictors of a poor prognosis in patients with CRC.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Amphiregulin; Biomarkers, Tumor; China; Colorectal Neoplasms; Disease Progression; EGF Family of Proteins; Enzyme-Linked Immunosorbent Assay; Epidermal Growth Factor; Epiregulin; Female; Glycoproteins; Humans; Hyperplasia; Immunoenzyme Techniques; Intercellular Signaling Peptides and Proteins; Male; Middle Aged; Neoplasm Invasiveness; Neoplastic Cells, Circulating; Precancerous Conditions; Prognosis

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

Human beta-defensins (hBDs) are small, cationic antimicrobial peptides produced by oral and other mucosal epithelia. More recently, hBDs have been shown to regulate adaptive immunity. In this study, we provide new information about the potential role of hBD-3 in the progression of oral cancer. In normal human oral epithelia, hBD-3 is produced by mitotically active cells in the basal layers of oral epithelium, whereas hBD-1 and -2 are coexpressed in the differentiated spinosum and granulosum layers. Interestingly, premalignant cells in carcinoma in situ lesions overexpress hBD-3, but not hBD-1 and hBD-2, correlating with specific recruitment and infiltration of macrophages. Our in vitro studies demonstrate that hBD-3 chemoattracts THP-1 monocytic cells and that epidermal growth factor (EGF) significantly induces hBD-3 expression in oral epithelial cells via mitogen-activated protein kinase (MAPK) kinase MEK1/2, p38 MAPK, protein kinase C (PKC), and phosphoinositide 3 kinase (PI3K), but not via Janus kinase (JAK) and signal transducer and activator of transcription (STATs). These results suggest that hBD-3 serves as a mitogen responsive gene in the initiation of oral cancer and may act as a motility signal to recruit tumor-associated macrophages.

Topics: beta-Defensins; Carcinoma in Situ; Carcinoma, Squamous Cell; Cell Movement; Epidermal Growth Factor; Humans; Macrophages; Microscopy, Fluorescence; Mouth Neoplasms; Phosphotransferases; Precancerous Conditions; STAT Transcription Factors

Lapatinib, a selective orally available inhibitor of epidermal growth factor receptor (EGFR) and ErbB2 receptor tyrosine kinases, is a promising agent for the treatment of breast cancer. We examined the effect of lapatinib on the development of mammary tumors in MMTV-erbB2 transgenic mice, which express wild-type ErbB2 under the control of the mouse mammary tumor virus promoter and spontaneously develop estrogen receptor (ER)-negative and ErbB2-positive mammary tumors by 14 months of age. Mice were treated from age 3 months to age 15 months with vehicle (n = 17) or lapatinib (30 or 75 mg/kg body weight; n = 16 mice per group) by oral gavage twice daily (6 d/wk). All statistical tests were two-sided. By 328 days after the start of treatment, all 17 (100%) of the vehicle-treated mice vs five (31%) of the 16 mice treated with high-dose lapatinib developed mammary tumors (P < .001). Among MMTV-erbB2 mice treated for 5 months (n = 20 mice per group), those treated with lapatinib had fewer premalignant lesions and noninvasive cancers in their mammary glands than those treated with vehicle (P = .02). Lapatinib also effectively blocked epidermal growth factor-induced signaling through the EGFR and ErbB2 receptors, suppressed cyclin D1 and epiregulin mRNA expression, and stimulated p27 mRNA expression in human mammary epithelial cells and in mammary epithelial cells from mice treated for 5 months with high-dose lapatinib. Thus, cyclin D1, epiregulin, and p27 may represent useful biomarkers of lapatinib response in patients. These data suggest that lapatinib is a promising agent for the prevention of ER-negative breast cancer.

Topics: Animals; Antineoplastic Agents; Biomarkers, Tumor; Breast Neoplasms; Carcinoma, Intraductal, Noninfiltrating; Cyclin D1; Epidermal Growth Factor; Epiregulin; ErbB Receptors; Female; Gene Expression Regulation, Neoplastic; Humans; Lapatinib; Mammary Neoplasms, Experimental; Mice; Mice, Transgenic; Precancerous Conditions; Protein Kinase Inhibitors; Quinazolines; Receptor, ErbB-2; Receptors, Estrogen; RNA, Messenger; Signal Transduction

The polarity protein complex Par6/atypical protein kinase (aPKC)/Cdc42 regulates polarization processes during epithelial morphogenesis, astrocyte migration, and axon specification. We, as well as others, have shown that this complex is also required for disruption of apical-basal polarity during the oncogene ErbB2-induced transformation and transforming growth factor beta-induced epithelial-mesenchymal transition of mammary epithelial cells. Here, we report that expression of Par6 by itself in mammary epithelial cells induces epidermal growth factor-independent cell proliferation and development of hyperplastic three-dimensional acini without affecting apical-basal polarity. This is dependent on the ability of Par6 to interact with aPKC and Cdc42, but not Lgl and Par3, and its ability to promote sustained activation of MEK/ERK signaling. Down-regulation of Cdc42 or aPKC expression suppresses the ability of Par6 to induce proliferation, demonstrating that Par6 promotes cell proliferation by interacting with aPKC and Cdc42. We also show that Par6 is overexpressed in breast cancer-derived cell lines and in both precancerous breast lesions and advanced primary human breast cancers, suggesting that Par6 overexpression regulates tumor initiation and progression. Thus, in addition to regulating cell polarization processes, Par6 is an inducer of cell proliferation in breast epithelial cells.

Topics: Adaptor Proteins, Signal Transducing; Breast Neoplasms; cdc42 GTP-Binding Protein; Cell Line, Tumor; Cell Polarity; Cell Proliferation; Epidermal Growth Factor; Extracellular Signal-Regulated MAP Kinases; Female; Humans; MAP Kinase Signaling System; Phosphorylation; Precancerous Conditions; Protein Kinase C; Receptors, Estrogen

The epidermal growth factor (EGF) pathway is important in esophageal adenocarcinoma (EAC) tumorigenesis. We hypothesized that the EGF A61G homozygous variant genotype (GG) is (a) both a risk and poor prognostic factor for EAC and (b) associated with higher EGF serum levels in individuals with gastroesophageal reflux disease (GERD).. Using unconditional logistic regression, we compared EGF A61G in 312 EAC cases and 447 GERD-free controls, adjusting for age, gender, smoking history, and healthy adult body mass index. Using the method of Kaplan and Meier, log-rank tests, and Cox proportional hazard models, we correlated EGF A61G with overall and failure-free survival in the EAC cases. Serum EGF levels and EGF genotype (G/G versus others) were correlated in 144 GERD patients using Wilcoxon rank sum tests.. The EGF A61G G/G genotype conferred increased EAC risk, with an adjusted odds ratio of 1.81 (95% confidence interval, 1.2-2.7), and was even higher in the subgroup of EAC patients with concurrent Barrett's esophagus (adjusted odds ratio, 2.18; 95% confidence interval, 1.3-3.7). However, EGF A61G was not associated with a more aggressive phenotype or prognosis in EAC patients. Higher serum EGF levels were found in GERD patients carrying G/G compared with A/A or A/G (P = 0.03, Wilcoxon rank sum test).. The EGF A61G G/G genotype is associated with a near 2-fold greater risk of EAC. The G/G allele was also associated with higher EGF levels in tumor-free patients with GERD. EGF genotyping can potentially identify high-risk patients with GERD and Barrett's metaplasia who might benefit from increased surveillance.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Barrett Esophagus; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Epidermal Growth Factor; Esophageal Neoplasms; Female; Gastroesophageal Reflux; Genetic Predisposition to Disease; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Polymorphism, Single Nucleotide; Precancerous Conditions; Risk Factors; Treatment Outcome

Cyclooxygenase-2 (COX-2) is induced in many breast cancers and COX-2 expression correlates with a worse outcome in the clinic. We hypothesized that the induction of genomic instability is a major mechanism through which COX-2 contributes to breast cancer progression.. We transfected a normal immortalized breast epithelial cell line of Basal B subtype, MCF10A, with the pSG5-COX-2 vector and established the stably transfected cell line MCF10A/COX-2. We analyzed the genomic instability phenotype by chromosomal analysis of metaphase-arrested MCF10A and MCF10A/COX-2 cells after Giemsa staining. Groups were compared using chi(2) tests. To investigate the DNA damage checkpoint signaling, we analyzed the phosphorylation status of CHK1 protein with a phospho-specific antibody.. Cytogenetic analysis of early passage transfected cells showed that COX-2 expression increased genomic instability compared with the MCF10A cells transfected with a luciferase vector alone. COX-2 overexpression was associated with a significant increase in chromosomal aberrations (fusions, breaks, and tetraploidy). There was a statistically significant increase in the number of polyploid cells in the COX-2 transfected cells versus the control (P=0.004). We also found that an inhibitory CHK1 phosphorylation at Ser-280 was dramatically increased upon COX-2 overexpression in MCF10A cells, thus explaining the mechanism of inactivation of an important cell cycle checkpoint. Further analysis of the MCF10A/COX-2 cells showed that these cells have acquired a premalignant phenotype characterized by a morphological transformation, a resistance to anoikis, a reduced requirement of epidermal growth factor for growth in culture, but their inability to establish tumors in a nude mouse model of malignancy.. We found that COX-2 expression in MCF10A breast epithelial cells confers a premalignant phenotype that includes enhanced genomic instability and altered cell-cycle regulation.

Topics: Animals; Anoikis; Breast; Breast Neoplasms; Cell Cycle; Cell Line; Checkpoint Kinase 1; Cyclooxygenase 2; Disease Progression; DNA Damage; Epidermal Growth Factor; Epithelial Cells; Female; Gene Expression Regulation, Enzymologic; Genomic Instability; Humans; Mice; Mice, Nude; Phenotype; Precancerous Conditions; Protein Kinases; Transfection; Transplantation, Heterologous

The recently cloned epidermal growth factor receptor related protein (ERRP) has been proposed to be a negative regulator of the epidermal growth factor receptor (EGFR). Because of the causal involvement of EGFR and its ligands in gastric cancer growth, we investigated expression of ERRP and cell proliferation in human gastric cancer.. We examined ERRP expression and localisation in surgical specimens of gastric cancers from 47 patients versus non-malignant gastric mucosa and determined their relationship to cell proliferation and differentiation. We also examined expression of ERRP by western blotting in three different gastric cancer cell lines. To further determine the functional properties of ERRP, we examined the effect of ERRP on epidermal growth factor (EGF) induced EGFR phosphorylation essential for its activation in MKN-28 gastric cancer cells.. ERRP expression was dramatically reduced in gastric cancers (34% of all specimens positive) compared with non-malignant gastric mucosa (66% of specimens positive). Expression of ERRP in cancer cells inversely correlated with cell proliferation and grade of malignancy. Cell lines derived from metastatic gastric cancers had reduced ERRP expression compared with cell lines derived from a non-metastatic cancer. Exogenous ERRP protein markedly inhibited EGF induced EGFR phosphorylation in gastric cancer cells providing a novel molecular mechanism of its action.. Our data indicate that downregulation of ERRP could play an important role in gastric cancer differentiation and progression. ERRP is a negative regulator of tumour cell proliferation and may exert its inhibitory effect, in part, by attenuating EGFR activation.

Topics: Adult; Aged; Amino Acid Sequence; Cell Differentiation; Cell Division; Disease Progression; Epidermal Growth Factor; ErbB Receptors; Female; Gastric Mucosa; Glycoproteins; Humans; Male; Middle Aged; Molecular Sequence Data; Neoplasm Proteins; Phosphorylation; Precancerous Conditions; Stomach Neoplasms; Tumor Cells, Cultured

Epidermal growth factor is an important mitogen for hepatocytes. Its overexpression promotes hepatocellular carcinogenesis. To identify the network of genes regulated through EGF, we investigated the liver transcriptome during various stages of hepatocarcinogenesis in EGF2B transgenic mice. Targeted overexpression of IgEGF induced distinct hepatocellular lesions and eventually solid tumours at the age of 6-8 months, as evidenced by histopathology. We used the murine MG U74Av2 oligonucleotide microarrays to identify transcript signatures in 12 tumours of small (n=5, pooled), medium (n=4) and large sizes (n=3), and compared the findings with three nontumorous transgenic livers and four control livers. Global gene expression analysis at successive stages of carcinogenesis revealed hallmarks linked to tumour size. A comparison of gene expression profiles of nontumorous transgenic liver versus control liver provided insight into the initial events predisposing liver cells to malignant transformation, and we found overexpression of c-fos, eps-15, TGIF, IGFBP1, Alcam, ets-2 and repression of Gas-1 as distinct events. Further, when gene expression profiles of small manifested tumours were compared with nontumorous transgenic liver, additional changes were obvious and included overexpression of junB, Id-1, minopontin, villin, claudin-7, RR M2, p34cdc2, cyclinD1 and cyclinB1 among others. These genes are therefore strongly associated with tumour formation. Our study provided new information on the tumour stage-dependent network of EGF-regulated genes, and we identified candidate genes linked to tumorigenes and progression of disease.

Topics: Animals; Carcinoma, Hepatocellular; Epidermal Growth Factor; Expressed Sequence Tags; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genes, fos; Homeodomain Proteins; Liver Neoplasms; Mice; Mice, Transgenic; Precancerous Conditions; Proto-Oncogene Protein c-ets-2; Proto-Oncogene Proteins; Repressor Proteins; Reverse Transcriptase Polymerase Chain Reaction; Trans-Activators; Transcription, Genetic

S100A6 (Calcyclin) is a calcium-binding protein that has been implicated in a variety of biological functions as well as tumorigenesis. The aim of our study was to investigate the involvement of S100A6 during prostate cancer development and progression. Using immunohistochemistry, the expression of S100A6 was examined in benign (n=66), premalignant (n=10), malignant (n=66) and metastatic prostate (n=5) tissues arranged in a tissue-microarray or whole sections as well as in prostate cancer cell lines. The S100A6 immunostaining pattern in tissues was compared with that of cytokeratin 5 (a basal cell marker) and 18 (a benign luminal cell marker). In all cases of benign epithelium, intense S100A6 expression was seen in the basal cell layer with absent staining in luminal cells. In all cases of prostatic adenocarcinoma (matched), metastatic lesions and 3/10 high-grade prostatic intraepithelial neoplasia lesions, an absence of S100A6 was seen. Western blotting and RT-PCR analysis of cell lines showed S100A6 expression to be absent in LNCaP, LNCaP-LN3 and LNCaP-Pro5 but present in Du145, PC3, PC-3M and PC-3M-LN4. LNCaP cells treated with 5-Azacytidine, caused re-expression of S100A6 mRNA. Sequencing of bisulphite modified DNA showed CpG methylation within the S100A6 promoter region and exon 1 of LNCaP, LNCaP-LN3 and LNCaP-Pro5 cell lines but not in Du145 cells. Our data suggest that loss of S100A6 protein expression is common in prostate cancer development and may occur at an early stage. The mechanism of loss of expression may involve hypermethylation of CpG sites. The finding of intense S100A6 expression in the basal cells of benign glands but loss of expression in cancer could be useful as a novel diagnostic marker for prostate cancer.

Topics: Adenocarcinoma; Blotting, Western; Cell Cycle Proteins; Diagnosis, Differential; DNA Methylation; Epidermal Growth Factor; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Male; Oligonucleotide Array Sequence Analysis; Precancerous Conditions; Prostate; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; S100 Calcium Binding Protein A6; S100 Proteins; Tumor Cells, Cultured

Hyperplastic mucosa adjacent to colon cancer, being a reactive change, accelerates cancer progression and its metastasis through expression of angiogenic factors. We investigated promoter methylation in hyperplastic mucosa adjacent to orthotopic KM12SM colon cancer in mice. In the hyperplastic mucosa adjacent to KM12SM tumors in the cecum of athymic mice, reductions in the levels of the mutL homologue 1 (MLH1) and O6-methylguanine-DNA methyltransferase (MGMT) proteins were detected by immunohistochemistry and immunoblotting. To examine the effects of growth factors and cytokines on promoter methylation and repressed expression of the MLH1 and MGMT genes, a rat intestinal epithelial cell line, IEC6, was treated with epidermal growth factor (EGF) and interleukin (IL)-15 for 35 days. Protein levels of MLH1 and MGMT were reduced in EGF- and IL-15-treated IEC6 cells. A methylation-sensitive restriction enzyme assay revealed that CpG methylation was present in the promoter regions of the MLH1 and MGMT genes in DNAs extracted from hyperplastic mucosa adjacent to KM12SM tumors. These findings suggest that promoter CpG methylation affects expression of MLH1 MGMT genes in hyperplastic mucosa adjacent to colon cancer.

Topics: Adaptor Proteins, Signal Transducing; Animals; Carrier Proteins; Colon; Colonic Neoplasms; CpG Islands; DNA Methylation; Epidermal Growth Factor; Epithelial Cells; Gene Expression Regulation, Neoplastic; Hyperplasia; Immunoblotting; Immunoenzyme Techniques; Interleukin-15; Intestinal Mucosa; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Mucous Membrane; MutL Protein Homolog 1; Neoplasm Proteins; Neoplasm Transplantation; Nuclear Proteins; O(6)-Methylguanine-DNA Methyltransferase; Precancerous Conditions; Promoter Regions, Genetic; Rats

It has been previously demonstrated that human ovarian cancer cells express FSH receptor (FSHR). However, whether FSHR plays a role in ovarian cancer development is still ambiguous. To investigate the role of FSHR in tumor progression, we overexpressed the receptor in SV40 Tag immortalized ovarian surface epithelium (OSE) cell lines (IOSE-80PC, a postcrisis line, and IOSE-398), which are preneoplastic and nontumorigenic. We compared the expression levels of several selected oncogenes in nontransfected (80PC), vector-transfected (80PCV), FSHR-transfected IOSE (80PCF) cells, and established ovarian cancer cell lines (OVCAR-3 and SKOV-3). Significantly increased protein levels of epithelial growth factor receptor, HER-2/neu, and c-Myc, but not K-Ras, were observed in FSHR-overexpressing 80PCF cells when compared with 80PCV cells. Constitutive phosphorylation of ERK1/2 was augmented in 80PCF cells, whereas phosphorylation of the other MAPK including p38 and Jun N-terminal kinase was unchanged. Considerable constitutive phosphorylation of ERK1/2 was also observed in OVCAR-3 and SKOV-3 cell lines when compared with 80PCV. More importantly, 80PCF cells grew more rapidly than 80PC and 80PCV cells. In conclusion, we have demonstrated that FSHR was highly expressed in OVCAR-3 and 80PCF cells transfected with FSHR overexpression vector. The 80PCF cell line showed increased levels of epithelial growth factor receptor, HER-2/neu, and c-myc and constitutive activation of ERK1/2. The rate of proliferation of the 80PCF cells was increased, compared with control cell lines. These results suggest that the overexpression of FSHR may be associated with enhanced levels of potential oncogenic pathways and increased proliferation in preneoplastic ovarian surface epithelial cells.

Topics: Cell Division; Cells, Cultured; Epidermal Growth Factor; Epithelial Cells; Female; Follicle Stimulating Hormone; Humans; Mitogen-Activated Protein Kinases; Oncogenes; Ovarian Neoplasms; Precancerous Conditions; Receptors, FSH; Transfection

Complex multiple interactions between cells and extracellular matrix occur during acinar morphogenesis involving integrin receptors and growth factors. Changes in these interactions occur during carcinogenesis as cells progress from a normal to a malignant, invasive phenotype. We have developed human prostatic epithelial cell lines of the same lineage, which represent multiple steps in carcinogenesis, similar to prostatic intraepithelial neoplasia and subsequent tumor progression. The non-tumorigenic, RWPE-1 and the tumorigenic WPE1-NB27 and WPE1-NB26 cell lines were used to examine their ability to undergo acinar morphogenesis in a 3-D cell culture model and its relationship to invasion, integrin expression and EGF presence. An inverse relationship between the degree of acinar formation and invasive ability was observed. The non-tumorigenic, non-invasive RWPE-1 and the low tumorigenic, low invasive, WPE1-NB27 cells show high and decreased acinar forming ability, respectively, while the more invasive WPE1-NB26 cells show a loss of acinar formation. While RWPE-1 acini show basal expression of alpha 6 beta 1 integrin, which correlates with their ability to polarize and form acini, WPE1-NB27 cells lack alpha 6 but show basal, but weaker expression of beta 1 integrin. WPE1-NB26 cells show loss alpha 6 and abnormal, diffused beta 1 integrin expression. A dose-dependent decrease in acinar formation was observed in RWPE-1 cells when cell proliferation was induced by EGF. Anti-functional antibody to EGF caused an increase in acinar formation in RWPE-1 cells. These results suggest that malignant cells lose the ability to undergo acinar morphogenesis and that the degree of this loss appears to be related to invasive ability, EGF levels and alterations in laminin-specific integrin expression. This model system mimics different steps in prostate carcinogenesis and has applications in the secondary and tertiary prevention of prostate cancer.

Topics: Antibodies; Cell Division; Cell Line; Cell Transformation, Neoplastic; Collagen; Disease Progression; Dose-Response Relationship, Drug; Drug Combinations; Epidermal Growth Factor; Epithelial Cells; Humans; Integrin alpha6beta1; Integrins; Laminin; Male; Morphogenesis; Neoplasm Invasiveness; Precancerous Conditions; Prostate; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; Proteoglycans

To elucidate factors responsible for altered proliferation of preneoplastic hepatocytes in rat hepatocarcinogenesis in vivo, EGF-stimulated DNA synthesis of normal and nodular hepatocytes in primary culture was studied. In addition, the influence of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) was investigated to clarify whether this potent tumor promoter differentially affects normal and nodular hepatocyte cultures. Unexpectedly it was found that in nodular hepatocytes spontaneous and EGF-stimulated DNA synthesis was enhanced with increasing cell density while DNA synthesis was inhibited in dense cultures of normal hepatocytes. Mitogenic responses were detected both by [3H]thymidine incorporation into DNA and by 5-bromo-2'-deoxyuridine labeling indices. TCDD (1 nM) acted as a mitoinhibitor both in normal and in nodular hepatocytes. The results suggest marked differences in growth behavior of nodular versus normal hepatocyte cultures probably due to paracrine stimulation by growth factors and altered cell-cell interaction.

Topics: Animals; Bromodeoxyuridine; Cell Count; Cells, Cultured; DNA; Epidermal Growth Factor; Liver; Male; Mitogens; Polychlorinated Dibenzodioxins; Precancerous Conditions; Rats; Rats, Wistar; Thymidine

Amphiregulin (Ar) and Cripto (Cr) are autocrine growth factors for mammary cells and both have been observed to exhibit high expression in human mammary tumors, in contrast with adjacent tissues. To investigate whether Ar and Cr play roles in the progression of mammary cell proliferation to unregulated growth and tumor formation, the levels of expression were examined in transgenic mice (TGM) that over-express several different oncogenes: MMTV-Polyoma virus middle T antigen (MMTV-PyMT), MMTV-c-ErbB2 (c-neu, HER2) and MT-hTGF alpha. These transgenic mice all produce mammary tumors but with different rates of progression. The levels of Ar were induced up to 10-fold in association with hyperplasia in 2 of the TGM. Cr overexpression was consistently observed in hyperplastic mammary glands in all the animal models, decreasing in overt tumors in 2 of the TGM models. In MMTV-PyMT mammary glands, the levels of Cr expression rose 7- to 10-fold in hyperplastic tissue and 25-fold the levels in tumors compared to age-matched transgene negative mice. Ar and especially Cr thus should have potential value as markers of preneoplastic change in mammary tissue.

Topics: Amphiregulin; Animals; Antigens, Viral, Tumor; Antineoplastic Agents; Biomarkers, Tumor; Cell Division; EGF Family of Proteins; Epidermal Growth Factor; Female; Genes, erbB-2; Glycoproteins; GPI-Linked Proteins; Growth Substances; Humans; Hyperplasia; Intercellular Signaling Peptides and Proteins; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Membrane Glycoproteins; Mice; Mice, Inbred Strains; Mice, Transgenic; Neoplasm Proteins; Oncogenes; Polyomavirus; Precancerous Conditions; Pregnancy; Receptor, ErbB-2

We set out to investigate the interactions between malignant transformation of keratinocytes, presence of oncoproteins and immunosurveillance in squamous cell carcinoma (SCC) and in a preneoplastic lesion, actinic keratosis (AK).. Samples of SCC, AK and normal skin (NS) were subjected to quantitative analysis using the following antibodies: anti-p53, Ki67, OKT6, OK-DR, B7/BB1, anti-CD54, anti-CD11, OKT3, OKT4, OKT8; positivity for ras-p21, EGFr and bcl-2 was evaluated by semiquantitative analysis.. Oncoprotein alterations and increased keratinocyte proliferative activity were observed both in AK and SCC. The number of Langerhans cells (CD1a+ cells) was similar in the two lesions but lower in SCC compared to AK. The proportion of CD1a(+)-B7/BB1+ cells was slightly higher in AK and SCC than in NS. The Langerhans cells expressed the HLA-DR antigen in all groups. Values were highest in AK and NS, and quite low in SCC. Cytotoxic T lymphocytes were more numerous in SCC than in AK and NS. Interestingly, the total CD4/CD8 ratio was much lower in SCC than in AK and NS, which indicates an increase in the CD8+ subpopulation in samples of SCC. In the epithelia of SCC samples there were a considerable number of B7/BB1+ keratinocytes.. We suggest that alterations in the immunodefence mechanisms have an important role in the transformation of AK into SCC, and that these changes affect not only lymphocytes, but also professional (i.e., Langerhans cells) and non-professional (i.e., keratinocytes) antigen presenting cells.

Topics: Aged; Analysis of Variance; Biopsy, Needle; Carcinoma, Squamous Cell; CD3 Complex; CD4 Antigens; CD8 Antigens; Cell Transformation, Neoplastic; Cells, Cultured; Epidermal Growth Factor; Female; HLA-DR Antigens; Humans; Immunohistochemistry; Intercellular Adhesion Molecule-1; Keratinocytes; Keratosis; Male; Middle Aged; Oncogene Proteins; Precancerous Conditions; Skin Neoplasms

The expression of EGF/EGFR in 47 laryngeal surgical specimens from 44 patients was examined. PCNA analysis as an index of proliferating cells was also performed in 32 cases of laryngeal cancer, six cases of pre-cancerous lesions and nine cases of normal laryngeal mucosa. EGFR failed to show a significant correlation with tumour behaviour, but EGF expression was statistically significantly higher in malignant (SCC) than in non-malignant tissues (pre-cancerous and normal tissues) (p < 0.006), and PCNA also showed a statistically significant difference (p < 0.016) between the two. In malignant tissues when EGF/EGFR in 'double-positive' and 'double-negative' cases was compared, a statistically significant difference in PCNA was found (p < 0.029); but this was not seen in non-malignant tissues. Our results support the hypothesis that an autocrime mechanism exists in laryngeal cancer and in this mechanism EGF may play an important role in tumour progression, especially when EGFR is overexpressed.

Topics: Adult; Aged; Aged, 80 and over; Carcinoma, Squamous Cell; Epidermal Growth Factor; ErbB Receptors; Female; Humans; Immunohistochemistry; Laryngeal Neoplasms; Larynx; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Staging; Precancerous Conditions; Proliferating Cell Nuclear Antigen

Increased phosphorylation in cancers can stimulate growth and up-regulate certain receptors. To test whether the functional response of phosphatase receptors is up-regulated during carcinogenesis, we examined the effects of ligands on net phosphorylation in isolated membranes derived from hamster cheek-pouch tissues undergoing malignant transformation. The buccal mucosa of groups of Syrian golden hamsters was exposed thrice weekly to 0.5% dimethylbenzanthracene (DMBA) in acetone for 2-12 weeks to produce premalignant and malignant tissues. Homogenates of these tissues were then incubated with [32P]ATP in the presence of epidermal growth factor (EGF), agonist of somatostatin analogue RC-160, luteinizing-hormone-releasing hormone (LH-RH) [D-Trp6]LH-RH, or combinations of EGF, RC-160, and [D-Trp6]LH-RH. Changes compared to controls in phosphorylation in response to ligands provided estimates of kinase or phosphatase activity. Phosphorylation increased continuously, from the first application of DMBA in a linear fashion, and independently of EGF stimulation. RC-160 and [D-Trp6]LH-RH reduced phosphorylation in vitro. This response occurred in premalignant (weeks 6-10 after DMBA application) as well as malignant tissues (week 12 after DMBA application), but was not significant in normal tissues. The results show a continuous augmentation in phosphatase activity prior to the appearance of cancers, but with a delay in expression following the primary event of increased kinase activity. Significantly less phosphorylation of substrates was induced by both RC-160 and [D-Trp6]LH-RH after in vitro activation by EGF than in the absence of EGF. This suggests that EGF activates latent systems of hormonal receptors. Collectively, these results support the hypothesis that the enhancement of the hormonally stimulated phosphatase in cancers occurs secondarily to the increased kinase activity.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Cricetinae; Epidermal Growth Factor; Gonadotropin-Releasing Hormone; Mesocricetus; Mouth Mucosa; Phosphorylation; Precancerous Conditions; Protein Tyrosine Phosphatases; Receptor Protein-Tyrosine Kinases; Somatostatin; Time Factors; Up-Regulation

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

Calcyclin is the product of a gene that is regulated in dependence of the cell cycle in fibroblasts in vitro. It has recently been proven to be a sialic acid-binding protein in vitro and in the case of mammalian tissues to bind specifically to annexin II, annexin VI, annexin XI, and glyceraldehyde-3-phosphate dehydrogenase in a Ca(2+)-dependent manner. Since calcyclin can be labelled without impairment of its binding activity, it can be employed as a histochemical tool to localize its accessible ligands. Concomitantly, immunohistochemical localization of calcyclin with a specific antibody is warranted. By using histochemical and immunohistochemical techniques, the expression of calcyclin and its accessible binding sites are demonstrated in serial sections of normal skin and benign, pre-cancerous and malignant tumors of the skin, namely in verruca vulgaris, papillary hidradenoma, syringoma, keratoacanthoma, Bowen's disease, squamous cell carcinoma, melanocytic naevi, primary and metastatic malignant melanoma and non-Hodgkin lymphoma (NHL) of the skin. Cytoplasmic and nuclear expression of calcyclin and its ligands is unexceptionally found in normal skin, epithelial tumors and benign melanocytic tumors. Presence of calcyclin and calcyclin-binding sites is detected in more than 80% of tumor cells in the epithelial lesions. In the group of melanomas and lymphomas heterogeneity is obvious. The application of annexin-specific antibodies raises evidence that members of this protein family co-localize with calcyclin in situ to some extent. These findings suggest that calcyclin and accessible calcyclin-binding molecules, like certain annexins, may be differentially regulated in melanomas and lymphomas in contrast to epithelial lesions with presently undefined biological implications.

Topics: Annexins; Calcium-Binding Proteins; Cell Cycle Proteins; Epidermal Growth Factor; Humans; Immunohistochemistry; Ligands; Precancerous Conditions; Reference Values; S100 Calcium Binding Protein A6; S100 Proteins; Skin; Skin Diseases; Skin Neoplasms; Tissue Distribution

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 studies were performed to clarify the significance of the expression or overexpression of epidermal growth factor (EGF), EGF-receptor (EGFR), p53, v-erb B, ras p21 in 23 cases each of tubular adenoma and adenocarcinoma. The expression of EGF, EGFR, p53, v-erb B, and ras p21 in paraffin-embedded tissues, from 46 patients with colorectal tumors (adenoma: 23 cases; 14 mild dysplasia, six moderate dysplasia, three severe dysplasia, adenocarcinoma: 23 cases; 17 well differentiated, two moderately differentiated, three poorly differentiated, one mucinous carcinoma was analyzed immunohistochemically using anti-EGF, EGFR, p53, v-erb B and ras p21 antibodies. The EGF and ras p21 tended to express more strongly in carcinoma cases than in the adenoma cases, and in severe and moderate dysplasia than in mild dysplasia (EGF: stained positive in five adenomas [21.74%] and 17 adenocarcinomas [73.91%]; ras p21: stained positive in six adenomas [26.09%] and 14 adenocarcinomas [60.87%]. The EGFR stained positive in two adenomas (8.70%) and two adenocarcinomas (8.70%). The p53 and v-erb B showed positive staining only in the carcinoma cases (p53: stained positive in four cases [17.39%]; v-erb B: stained positive in eight cases [34.78%]). This study suggests that these factors seem to have some role in the progression of colon neoplasms. It suggests that genetic alteration is not always equal to the overexpression of protein products, but that it reflects them well, and that the staining makes some contribution to differential diagnosis in colorectal neoplasms.

Topics: Adenocarcinoma; Adenoma; Adult; Aged; Aged, 80 and over; Colorectal Neoplasms; Epidermal Growth Factor; ErbB Receptors; Female; Humans; Immunohistochemistry; Male; Middle Aged; Neoplasm Proteins; Neoplasms, Glandular and Epithelial; Oncogene Proteins v-erbB; Precancerous Conditions; Proto-Oncogene Proteins p21(ras); Retroviridae Proteins, Oncogenic; Tumor Suppressor Protein p53

A series of mouse mammary epithelial cell lines has been established by a protocol that gives highly reproducible results. The mammary epithelial cell lines, designated as FSK lines, were judged to be epithelial based on positive immunostaining for keratin-intermediate filaments, negative immunostaining for vimentin-intermediate filaments, hormonal induction of casein, and the ability to exhibit ductal and alveolar mammary morphogenesis in vivo. The FSK cell lines are dependent on epidermal growth factor and insulin in a low serum (1%) medium. Conditioned medium from spindle cell cultures replaced the requirement for serum and increased the growth of FSK3 and FSK4 4-5 times in collagen gels and 12-14 times in monolayer culture, respectively. Following injection into the mammary fat pad at passages 2-11, the FSK cell lines generated stable transplantable hyperplastic alveolar outgrowth lines. The in vivo outgrowth lines were judged as preneoplastic based on their stable alveolar morphology in vivo and an increased susceptibility for tumorigenesis. The FSK cell lines and their derivative in vivo outgrowth lines provide a new and potentially productive system to examine critical molecular alterations involved in the development of mammary preneoplasias. Furthermore, the reproducibility of the in vitro culture system provides the assurance that stable cell lines of mouse mammary epithelial cells can be generated easily and at will.

Topics: Adenocarcinoma, Bronchiolo-Alveolar; Animals; Carcinoma, Intraductal, Noninfiltrating; Cell Division; Cell Line; Culture Techniques; Epidermal Growth Factor; Epithelial Cells; Female; Fluorescent Antibody Technique; Keratins; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Precancerous Conditions

The protein peanut agglutinin (PNA) is a galactose-binding lectin whose receptor, the Thomsen-Friedenreich (TF) blood-group antigen, shows increased expression in hyperplastic and neoplastic colonic epithelium.. Our hypothesis was that, under these conditions, increased lectin receptors could interact with dietary lectins, which would act as tumor promoters by stimulating cell proliferation. This study was designed to confirm whether active PNA is recoverable from feces after ingestion of peanuts and to assess the mitogenic effect of PNA on proliferation of epithelial cells in the colon.. Peanut lectin was extracted from feces by lactose-agarose affinity chromatography and was assayed for hemagglutinating activity. Cultured explants of histologically normal biopsy specimens of colonic mucosa from 31 patients were examined. Crypt cell production rate and incorporation of [3H]N-acetylglucosamine into mucin were assessed as indicators of proliferative and metabolic responses to PNA. In addition, we evaluated the separate and combined effects of PNA and epidermal growth factor (EGF) on cell proliferation in human HT29 colorectal cancer cells, by using tritiated thymidine incorporation and cell counts.. Peanut lectin extracted from feces showed hemagglutinating activity toward desialylated red blood cells similar to that of a lectin preparation extracted from raw peanuts. Evaluation of biopsy specimens of normal colonic mucosa demonstrated that PNA at a concentration of 25 micrograms/mL caused statistically significant increases in crypt cell production (31% [mean] +/- 5% [SD]; P = .00005) and mucus synthesis (77% +/- 12%; P less than .000001). At 7.5-100 micrograms/mL, PNA was mitogenic for the HT29 colorectal cancer cell line. At 25 micrograms/mL, PNA alone produced a statistically significant increase in thymidine incorporation (44% [mean] +/- 3.7% [SD]; P = .002). For PNA in combination with EGF at 100 pg/mL, the increase was significantly greater (222% +/- 11.2%) than that for EGF alone (57% +/- 5%; P = .003).. These results suggest that expression of the PNA receptor, TF antigen, by hyperplastic or neoplastic colonic epithelium may affect cell proliferation.. It is possible that dietary lectins such as PNA, which bind to the TF antigen, promote cell proliferation and thus cancerous growth, while galactose-containing vegetable fiber would inhibit this effect by competing for binding by these lectins.

Topics: Arachis; Carbohydrate Sequence; Cell Division; Colon; Colonoscopy; Colorectal Neoplasms; Diet; Epidermal Growth Factor; Epithelium; Feces; Hemagglutination Tests; Humans; Intestinal Mucosa; Lectins; Molecular Sequence Data; Mucus; Peanut Agglutinin; Plant Lectins; Precancerous Conditions; Receptors, Mitogen; Tumor Cells, Cultured

Four tumor promoters, i.e. PB, TPA, NAF, and DDT, added singly to a calcium-deprived synthetic medium, elicited early and late mitogenic effects and concurrent surges of nuclear poly(ADP-ribose) polymerase (pADPRP) activity in primary neonatal rat hepatocytes mutagenized with an intra-uterine dose of DMN. These actions were fully abated by the pADPRP inhibitor 3-MBA. Conversely, EGF only acted as a full mitogen when medium's calcium was at physiological levels, and its effects could not be blocked by 3-MBA. The same tumor promoters, but not EGF, also evoked a swift and lingering amplification of pADPRP transcripts in DMN-initiated hepatocytes kept in low-calcium medium. Hence, a coordinated modulation of both pADPRP transcripts and activity by xenobiotics is likely to be involved in the clonal expansion of early preneoplastic hepatocytes.

Topics: Animals; Animals, Newborn; Benzamides; Calcium; Cell Cycle; Cell Nucleus; Cells, Cultured; Dimethylnitrosamine; DNA Replication; Epidermal Growth Factor; Female; Kinetics; Liver; Liver Neoplasms; Maternal-Fetal Exchange; Mutagenesis; Phenobarbital; Poly(ADP-ribose) Polymerases; Precancerous Conditions; Pregnancy; Rats; Rats, Inbred Strains; Sodium Fluoride; Tetradecanoylphorbol Acetate; Thymidine; Transcription, Genetic

We studied the effects of hormonal manipulation by orchiectomy, alone or in combination with the aromatase inhibitor aminoglutethimide (AGT), and by luteinizing hormone-releasing hormone agonist (LH-RH-A) (goserelin) treatment on the development of early putative (pre)neoplastic lesions induced in the pancreas of rats and hamsters by azaserine and N-nitrosobis(2-oxopropyl)amine respectively. Treatment of the animals started 1 week after the last injection with carcinogen and continued for 4 months. Orchiectomy caused a significant inhibition of growth of acidophilic atypical acinar cell nodules in the rat model, whereas surgical castration did not show an effect in the hamster model. In rats, but not in hamsters, orchiectomy resulted in a significant decrease in body weight and in absolute, but not relative pancreatic weight. Treatment of the animals with AGT or goserelin did not cause a significant effect on the development of either putative preneoplastic acinar lesions in rat pancreas or early ductular lesions in hamster pancreas. Hamsters showed clearly higher plasma epidermal growth factor (EGF) and insulin-like growth factor 1 (IGF-1) concentrations than rats, while plasma testosterone levels were significantly lower. Plasma EGF and IGF-1 levels decreased with increasing age in both control and treatment groups. Compared to controls there were no clear unequivocal effects of treatment on EGF, IGF-1 and gastrin levels. Plasma testosterone levels decreased by orchiectomy and LH-RH-A treatment. In rats hormone-induced effects on food intake and altered nutritional status might be important with respect to the development of carcinogen-induced preneoplastic pancreatic lesions.

Topics: Aminoglutethimide; Animals; Azaserine; Body Weight; Buserelin; Carcinogens; Cricetinae; Epidermal Growth Factor; Gastrins; Goserelin; Male; Mesocricetus; Nitrosamines; Orchiectomy; Organ Size; Pancreatic Neoplasms; Precancerous Conditions; Rats; Rats, Inbred Strains; Somatomedins; Testosterone

The concentration of insulin-like growth factor-I (IGF-I) and its relationship to other biochemical parameters of cyst fluids was investigated in 94 cyst fluids of 86 women with gross cystic breast disease. The relationship between the biochemical parameters and the cytological features of breast fluids (presence or absence of apocrine cells) was also studied. IGF-I was detected in all tested fluids, with a concentration 50 to 100 times lower than that found in plasma. IGF-I concentration was higher in cysts with a Na+/K+ ratio greater than 3 (greater than 3) and was inversely related to both dehydroepiandrosterone sulfate (DHEA-S) and epidermal growth factor (EGF) concentration (p less than 0.001). It is suggested that Na+/K+ greater than 3 cysts have a higher permeability to plasma and extracellular fluids compared to Na+/K+ less than 3 cysts. Apocrine cells were found in 78% of Na+/K+ less than 3 fluids as well as in 53% of Na+/K+ greater than 3 fluids. A well-defined relationship was found between the biochemical parameters of breast fluids, but the presence of either IGF-I or EGF was not related to the morphology of breast cysts as assessed by cytological examination.

Topics: Biopsy, Needle; Body Fluids; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Epidermal Growth Factor; Epithelium; Female; Fibrocystic Breast Disease; Humans; Insulin-Like Growth Factor I; Metaplasia; Potassium; Precancerous Conditions; Sodium

It has been established for the first time that in extracts of the regenerating and preneoplastic (4 months after the beginning of carcinogen introduction) intestine as well as in the peritumor tissue the content of EPR-similar polypeptides and insulin raises, whereas in tumours it remains not high. Proteins with molecular weight greater than 120 kD able to compete with 125I-EPR for the binding with the receptors of EPR and being, evidently, the precursors of EPP are found in case of carcinogenesis. Besides, the content of insulin receptors rises, this process being most typical of the large intestine.

Topics: Animals; Chromatography, Gel; Electrophoresis; Epidermal Growth Factor; ErbB Receptors; Insulin; Intestinal Mucosa; Intestinal Neoplasms; Male; Precancerous Conditions; Protein Precursors; Rats; Receptor, Insulin; Regeneration

The epidermal growth factor (EGF) and alpha-tumor growth factor are mitogenic proteins which bind to the EGF-receptor and may play a role in carcinogenesis or tumor progression. Our study investigated whether colorectal carcinomas and adenomas express altered levels of EGF-receptors or overproduce EGF-like activity by comparing histologically normal mucosa to carcinomas resected from the same patients. EGF-receptors were characterized by radioligand binding studies. Carcinomas contained unchanged or decreased levels of EGF-receptors in 13/16 and moderately increased levels in 3/16 patients as compared to normal mucosa. Adenomas obtained from 2 patients with familial polyposis coli and from a third patient with a coincident carcinoma had similar numbers of EGF-receptors as normal mucosa. EGF-like growth factors, in contrast, were significantly elevated in carcinoma extracts as compared to extracts from normal mucosa of the same patients. Adenomas did not contain elevated levels of EGF-like activity. We conclude that increased expression of EGF-receptors is infrequent in colonic adenocarcinomas. Increased production of EGF-like growth factors may frequently occur but seems to be associated with tumor progression rather than with premalignant lesions as represented by adenomas.

Topics: Adenomatous Polyposis Coli; Adult; Aged; Cell Division; Colon; Colonic Polyps; Colorectal Neoplasms; Epidermal Growth Factor; ErbB Receptors; Female; Humans; Intestinal Mucosa; Male; Middle Aged; Neoplasm Staging; Precancerous Conditions; Rectum

Sialoadenectomies performed on 8-week-old female SHN and GR mice markedly reduced the numbers of precancerous and cancerous lesions in their mammary glands that had been mildly hypoplastic; the mice were necropsied when they were 30 weeks old. The success rate of the mammary cancer transplantation to isogenic male SHN or C3H mice was lower in the sialoadenectomized animals, and growth of the grafted tumors was delayed after gland removal. Some tumor development resumed in the hosts that received mouse epidermal growth factor after surgery. Therefore, we believe this growth factor may play a role in the multistage process of mouse mammary carcinogenesis.

Topics: Animals; Epidermal Growth Factor; Female; Male; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C3H; Neoplasm Transplantation; Precancerous Conditions; Submandibular Gland

The v-fps oncoprotein was expressed in a pre-neoplastic, growth factor-dependent Chinese hamster lung fibroblast line (CCL39) to study its effect on growth controls and on the induction of malignancy. Two transfectants were characterized which expressed low (39FPS-8) or high (51FPS-6) levels of P130gag-f ps protein-tyrosine kinase activity. 39FPS-8 cells still arrested in quiescence when deprived of growth factors, but developed an increased sensitivity to the mitogenic actions of epidermal growth factor (20-fold) and alpha-thrombin (50-fold), although not to insulin. In contrast, 51FPS-6 cells completely escaped growth controls, divided in serum-free medium, and were insensitive to further growth factor stimulation. Both transfectants produced rapidly growing tumors in nude mice that formed pulmonary metastases from a subcutaneous site, unlike the parental cells which are non-metastatic. 51FPS-6 cells were comparatively more efficient than 39FPS-8 cells in colonizing the lungs after intravenous inoculation. The v-fps tyrosine kinase therefore induces a partial to complete relaxation of growth factor-mediated controls on the CCL39 cell cycle, with the extent of factor independence reflecting the amount of P130gag-f ps synthesized. This reduction in growth factor requirements correlates with the capacity of v-fps to confer the attributes of metastatic tumors upon preneoplastic CCL39 fibroblasts. We speculate that increased sensitivity to growth factor stimulation represents a common mechanism by which tumor cells acquire metastatic properties.

Topics: Animals; Cell Division; Cell Line; Cricetinae; Epidermal Growth Factor; Growth Substances; Insulin; Interphase; Lung; Lung Neoplasms; Neoplasm Metastasis; Oncogene Proteins, Viral; Precancerous Conditions; Protein-Tyrosine Kinases; Thrombin

The binding of epidermal growth factor, asialoorosomucoid, and apoprotein E-rich lipoproteins to isolated hepatocytes was investigated at various time intervals during the step-by-step development of liver cancer in rats. The degree of binding of the three ligands showed a progressive reduction in early persistent and late persistent putative preneoplastic hepatocyte nodules. This was further decreased in hepatocytes isolated from unequivocal hepatocellular carcinomas. Regenerating liver hepatocytes bound lesser amounts of epidermal growth factor and asialoorosomucoid than did hepatocytes from control resting liver but increased amounts of apoprotein E-rich lipoproteins. The progressive decrease in ligand binding during the precancerous phase of hepatocarcinogenesis, the nodule-to-cancer sequence, may render nodules less responsive to the influences of their external environments.

Topics: Animals; Apolipoproteins E; Asialoglycoproteins; Chemical and Drug Induced Liver Injury; Epidermal Growth Factor; Ligands; Lipoproteins; Liver; Liver Diseases; Liver Neoplasms, Experimental; Liver Regeneration; Male; Orosomucoid; Precancerous Conditions; Rats; Rats, Inbred F344; Receptors, Cell Surface

The influences of purified transforming growth factor beta (TGF-beta) on proliferation of normal, preneoplastic, and neoplastic rat hepatocytes were examined in primary monolayer culture with or without prior stimulation with epidermal growth factor (EGF). Hepatocytes from normal livers or discrete preneoplastic nodules or carcinomas generated in F344 rats by the Solt-Farber model were isolated and cultured in serum-free modified Williams' E. medium for up to 72 h. Proliferation was quantified by labeling index by [3H]thymidine autoradiography. The majority of normal hepatocytes became labeled in response to EGF (20 ng/ml) between 24 and 72 h. TGF-beta had a dose-dependent inhibitory effect which was virtually complete at concentrations above 0.5 ng/ml added at 0 h together with EGF. Hepatocytes from all nodule and carcinoma populations were less stimulated by EGF but also strongly inhibited by TGF-beta. Hepatocytes isolated from normal livers 24 h after partial hepatectomy were similarly inhibited by TGF-beta. The minimal initial exposure period for TGF-beta to maximally inhibit was 2 h. TGF-beta added at various times between 8 and 48 h after EGF partially inhibited the labeling index to levels that were constant but substantially greater than the labeling index at the time TGF-beta was added. A proportion of hepatocytes from normal and nodular livers became resistant to the inhibitory effects of TGF-beta between 48 and 72 h, suggesting that the inhibitory effect is transient. TGF-beta added at 0 h also virtually completely inhibited the labeling of normal and nodular hepatocytes that were not exposed to EGF. These studies demonstrate that TGF-beta is a potent negative regulator of proliferation of normal, regenerating, preneoplastic, and neoplastic hepatocytes. This suggests that persistent proliferation of neoplastic hepatocytes in vivo cannot be explained by a difference in response to TGF-beta.

Topics: Animals; Cell Division; Cells, Cultured; Dose-Response Relationship, Drug; Epidermal Growth Factor; Liver Neoplasms; Male; Peptides; Precancerous Conditions; Rats; Rats, Inbred F344; Time Factors; Transforming Growth Factors; Tumor Cells, Cultured

Transplantation of fetal salivary mesenchyma into adult mammary glands resulted in atypical outgrowths from the mammary duct system. These duct-alveolus nodules (DAN) were distinguishable from hyperplastic alveolar nodules (HAN) that arose from normal mammary duct systems in mice infected with murine mammary tumor virus (MuMTV). DAN displayed a type of ductal branching characteristic of salivary gland rather than of mammary gland, reflecting a tissue-specific perturbation of epithelium-mesenchyma in DAN in milk-transmitted MuMTV-infected C3H/HeN mice and in MuMTV-negative BALB/c mice given 7,12-dimethylbenz[a]anthracene (DMBA) subsequent to transplantation of fetal salivary mesenchyma. Mammary cancers were not increased in milk-transmitted MuMTV-free C3H/HeN and GRS/A mice that received salivary mesenchyma transplants. Salivary mesenchyma accelerated mammary carcinogenesis by increasing the mammary epithelial cell population responsive to MuMTV and DMBA.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Carcinoma, Intraductal, Noninfiltrating; Epidermal Growth Factor; Female; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Inbred Strains; Precancerous Conditions; Salivary Glands; Transplantation, Isogeneic