bromochloroacetic-acid and Cell-Transformation--Viral

Topics: Animals; Antigens, Polyomavirus Transforming; Antigens, Viral, Tumor; Breast; Carcinoma, Squamous Cell; Cell Survival; Cell Transformation, Neoplastic; Cell Transformation, Viral; Cells, Cultured; Epithelium; Female; Humans; Keratins; Male; Methods; Oncogene Proteins, Viral; Oncogenes; Organ Specificity; Phenotype; Pregnancy; Simian virus 40; Skin

Papillomaviruses induce tumors of keratinocytes. Vegetative viral DNA replication and virion assembly are seen in those cells which are in the process of keratinizing or are keratinized. To date, no cell culture system has been developed that permits expression of the complete viral life cycle. Keratinocytes infected in culture may harbor the virus as a stable, replicating episome, but they do not support vegetative viral growth, nor do they become immortalized or transformed. The major obstacle in using keratinocyte cultures may be related to a dual need for transformation and full differentiation. Some animal papillomaviruses have been shown to be capable of transforming cultured murine fibroblasts. The fibroblast model is useful for identifying the viral-transforming gene(s) and their products.

Topics: Animals; Cattle; Cell Line; Cell Transformation, Viral; DNA Replication; Epidermal Cells; Epidermis; Fibroblasts; Humans; Keratins; Laryngeal Neoplasms; Mice; Papilloma; Papillomaviridae; Rabbits; Virus Cultivation; Virus Replication

It is speculated that bats are important reservoir hosts for numerous viruses, with 27 viral families reportedly detected in bats. Majority of these viruses have not been isolated and there is little information regarding their biology in bats. Establishing a well-characterized bat cell line supporting the replication of bat-borne viruses would facilitate the analysis of virus-host interactions in an in vitro model. Currently, few bat cell lines have been developed and only Tb1-Lu, derived from Tadarida brasiliensis is commercially available. Here we describe a method to establish and immortalize big brown bat (Eptesicus fuscus) kidney (Efk3) cells using the Myotis polyomavirus T-antigen. Subclones of this cell line expressed both epithelial and fibroblast markers to varying extents. Cell clones expressed interferon beta in response to poly(I:C) stimulation and supported the replication of four different viruses, namely, vesicular stomatitis virus (VSV), porcine epidemic diarrhea coronavirus (PED-CoV), Middle-East respiratory syndrome coronavirus (MERS-CoV) and herpes simplex virus (HSV). To our knowledge, this is the first bat cell line from a northern latitude insectivorous bat developed using a novel technology. The cell line has the potential to be used for isolation of bat viruses and for studying virus-bat interactions in culture.

Topics: Animals; Antigens, Polyomavirus Transforming; Cell Culture Techniques; Cell Line; Cell Transformation, Viral; Chiroptera; Epithelial Cells; Fibroblasts; Keratins; Kidney; Middle East Respiratory Syndrome Coronavirus; Polyomavirus; Porcine epidemic diarrhea virus; Simplexvirus; Vesiculovirus; Vimentin

Epidermolytic ichthyosis (EI) is a skin fragility disorder caused by mutations in genes encoding suprabasal keratins 1 and 10. While the aetiology of EI is known, model systems are needed for pathophysiological studies and development of novel therapies.. To generate immortalized keratinocyte lines from patients with EI for studies of EI cell pathology and the effects of chemical chaperones as putative therapies.. We derived keratinocytes from three patients with EI and one healthy control and established immortalized keratinocytes using human papillomavirus 16-E6/E7. Growth and differentiation characteristics, ability to regenerate organotypic epidermis, keratin expression, formation of cytoskeletal aggregates, and responses to heat shock and chemical chaperones were assessed.. The cell lines EH11 (K1_p.Val176_Lys197del), EH21 (K10_p.156Arg>Gly), EH31 (K10_p.Leu161_Asp162del) and NKc21 (wild-type) currently exceed 160 population doublings and differentiate when exposed to calcium. At resting state, keratin aggregates were detected in 9% of calcium-differentiated EH31 cells, but not in any other cell line. Heat stress further increased this proportion to 30% and also induced aggregates in 3% of EH11 cultures. Treatment with trimethylamine N-oxide and 4-phenylbutyrate (4-PBA) reduced the fraction of aggregate-containing cells and affected the mRNA expression of keratins 1 and 10 while 4-PBA also modified heat shock protein 70 (HSP70) expression. Furthermore, in situ proximity ligation assay suggested a colocalization between HSP70 and keratins 1 and 10. Reconstituted epidermis from EI cells cornified but EH21 and EH31 cells produced suprabasal cytolysis, closely resembling the in vivo phenotype.. These immortalized cell lines represent a useful model for studying EI biology and novel therapies.

Topics: Adolescent; Adult; Cell Line; Cell Transformation, Viral; Epidermis; Hot Temperature; HSP70 Heat-Shock Proteins; Humans; Hyperkeratosis, Epidermolytic; Keratinocytes; Keratins; Male; Methylamines; Models, Biological; Phenotype; Phenylbutyrates; Stress, Physiological; Young Adult

Normal human epithelial cell cultures exhibit a limited (although different between tissues) lifespan in vitro. In previous studies, urothelial cell cultures were immortalized using retroviral transformation with human papillomavirus type 16 E6 and E7 genes, in undefined culture systems containing serum or bovine pituitary extract.. Due to the variability of results in such systems, we instead developed a procedure for the immortalization of urothelial cells using a defined, serum-free culture system.. Immortalization through retroviral transformation with human papillomavirus type 16 E6 and E7 was successful, and transformation of urothelial cells conferred an extended over normal lifespan and restored telomerase activity. Transformed cells retained typical morphology and exhibited a similar growth rate, cytokeratin immunoreactivity pattern, and response to growth factors as observed in untransformed cells. Karyotype analysis revealed a gradual accumulation of genetic mutations that are consistent with previously reported mutations in epithelial cells transformed with human papillomavirus type 16 E6 and E7.. The ability to extend the in vitro lifespan of cells holds the potential to reduce the continuous need for tissue samples and to enable complete investigations with one cell line.

Topics: Animals; Cell Cycle; Cell Growth Processes; Cell Line, Transformed; Cell Transformation, Viral; Cells, Cultured; Clone Cells; Culture Media, Serum-Free; Epidermal Growth Factor; ErbB Receptors; Genes, Viral; Human papillomavirus 16; Humans; Karyotyping; Keratins; Mice; Oncogene Proteins, Viral; Papillomavirus E7 Proteins; Papillomavirus Infections; Phenotype; Quinazolines; Repressor Proteins; Telomerase; Urothelium

Human papillomaviruses (HPV) have been associated with the development of non-melanoma skin cancer (NMSC) but the molecular mechanisms of the role of the virus in NMSC development are not clearly understood. Abnormal epithelial differentiation seen in malignant transformation of keratinocytes is associated with changes in keratin expression. The purpose of this study was to investigate the phenotype of primary human adult keratinocytes expressing early genes of HPV8 with specific reference to their differentiation and cell cycle profile to determine whether early genes of HPV8 lead to changes that are consistent with transformation. The expression of HPV8 early genes either individually or simultaneously caused distinct changes in the keratinocyte morphology and induced an abnormal keratin expression pattern, that included simple epithelial (K8, K18, K19), hyperproliferation-specific (K6, K16), basal-specific (K14, K15) and differentiation-specific (K1, K10) keratins. Our results indicate that expression of HPV8 early genes disrupts the normal keratin expression pattern in vitro. Expression of HPV8-E7 alone caused polyploidy that was associated with decreased expression of p21 and pRb. Expression of individual genes or in combination differentially influenced cell morphology and cell cycle distribution which might be important in HPV8-induced keratinocyte transformation.

Topics: Adult; Alphapapillomavirus; Blotting, Western; Cell Cycle; Cell Differentiation; Cell Transformation, Viral; Flow Cytometry; Gene Expression Regulation; Genetic Vectors; Humans; Immunohistochemistry; Keratinocytes; Keratins; Moloney murine leukemia virus; Polyploidy; Reverse Transcriptase Polymerase Chain Reaction; Transcription, Genetic; Tumor Suppressor Proteins

Epithelial-mesenchymal transformation is now recognised as an important feature of tissue remodelling. The present report concerns the role of adenovirus infection in inducing this transformation in an animal model of chronic obstructive pulmonary disease. Guinea pig primary peripheral lung epithelial cells (PLECs) transfected with adenovirus E1A (E1A-PLECs) were compared to guinea pig normal lung fibroblasts (NLFs) transfected with E1A (E1A-NLFs). These cells were characterised by PCR, immunocytochemistry, electron microscopy, and Western and Northern blot analyses. Electrophoretic mobility shift assays were performed in order to examine nuclear factor (NF)-kappaB and activator protein (AP)-1 binding activities. E1A-PLECs and E1A-NLFs positive for E1A DNA, mRNA and protein expressed cytokeratin and vimentin but not smooth muscle alpha-actin. Both exhibited cuboidal morphology and junctional complexes, but did not contain lamellar bodies or express surfactant protein A, B or C mRNAs. These two cell types differed, however, in their NF-kappaB and AP-1 binding after lipopolysaccharide stimulation, possibly due to differences in the expression of the subunits that comprise these transcriptional complexes. E1A transfection results in the transformation of peripheral lung epithelial cells and normal lung fibroblasts to a phenotype intermediate between that of the two primary cells. It is postulated that this intermediate phenotype may play a major role in the remodelling of the airways in chronic obstructive pulmonary disease associated with persistence of adenovirus E1A DNA.

Topics: Actins; Adenovirus E1A Proteins; Animals; Binding Sites; Blotting, Northern; Blotting, Western; Cell Transformation, Viral; Cells, Cultured; DNA, Viral; Electrophoretic Mobility Shift Assay; Epithelial Cells; Female; Fibroblasts; Guinea Pigs; Immunoenzyme Techniques; Keratins; Lung; Mesoderm; Microscopy, Electron; Muscle, Smooth; NF-kappa B; Phenotype; Polymerase Chain Reaction; Pulmonary Surfactant-Associated Protein A; RNA, Messenger; RNA, Viral; Transcription Factor AP-1; Transfection; Vimentin

To analyze the effect of Pygeum africanum extracts on the in vitro proliferation of human prostate cells.. Prostate cancer cell lines and benign prostatic hyperplasia derived epithelial cells were cultured and treated with P. africanum extracts. The effect on cell proliferation was monitored by H3-thymidine and bromodeoxyuridine uptake and flow cytometry assays.. The incubation with P. africanum extracts, with or without addition of amino acids, significantly and in a dose-dependent manner inhibits the proliferation of prostate cancer derived cells LnCaP, PZ-HPV-7, and CA-HPV-10. In the PZ-HPV-7 cells P. africanum extracts counteract the mitogenic action of EGF and block the transition from G1 to S in the cell cycle. P. africanum extracts also exert a potent antimitogenic action on the epithelial cells derived from benign prostatic hyperplasia explants.. The ethanolic P. africanum extracts have an antimitogenic effect on prostate cancer cells and benign prostatic hyperplasia epithelial cells. Such effect is associated with the inhibition of the mitogenic action of EGF, and it is accompanied by a decrease of cells entering the S Phase of the cell cycle.

Topics: Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Culture Media, Serum-Free; DNA Replication; Drug Evaluation, Preclinical; Epithelial Cells; Ethanol; Flow Cytometry; Growth Inhibitors; Humans; Keratins; Male; Mitosis; Neoplasm Proteins; Organ Culture Techniques; Papillomaviridae; Plant Extracts; Prostate; Prostatic Hyperplasia; Prostatic Neoplasms; Prunus africana; Stromal Cells; Tumor Cells, Cultured

Epithelial-mesenchymal transition (EMT) may be critical for neoplastic progression and its eventual tumorigenicity of epithelia. In this context, we investigated whether EMT and EMT-associated features occurred after chronic ethanol treatment of human gingival keratinocytes immortalized with the E6/E7 oncogenes of human papillomavirus (HPV) type 16. Following a nine-week treatment of cells with 30 mM ethanol in keratinocyte growth medium, they were cultured in normal DMEM with 10% serum. These cell populations were able to proliferate in this medium gradually exhibiting elongated morphology indicating that these cells underwent EMT. Control cells without ethanol treatment did not survive subcultures in DMEM. Upon long-term subcultures of ethanol-treated cells, two phenotypes were obtained exhibiting epithelium-like and spindle-shape fibroblast-like morphology (respectively, termed as EPI and FIB cells), the latter indicating EMT. In comparison to EPI cells, the phenotypic transition to FIB cells was concomitant with a decrease in the expression of keratins, desmoplakins and a complete loss of K14. Moreover, FIB cell transition strongly correlates with an increase in the expression of vimentin and simple epithelial keratin K18. These alterations in FIB cells were associated with the ability of these cells to exhibit anchorage-independent growth, while EPI cells exhibited anchorage-dependent growth. Concerning the transformation stage, FIB cells represent a progressively more advanced transformed phenotype which may reflect an early step during HPV- and ethanol-dependent multi-step carcinogenesis.

Topics: Animals; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Cell Transplantation; Cells, Cultured; Epithelial Cells; Ethanol; Fibroblasts; Gingiva; Humans; Immunoblotting; Keratin-14; Keratinocytes; Keratins; Male; Mice; Mice, Nude; Microscopy, Confocal; Neoplasms, Experimental; Oncogene Proteins, Viral; Papillomaviridae; Papillomavirus E7 Proteins; Repressor Proteins; Transplantation, Heterologous; Vimentin

Epidermolysis bullosa simplex (EBS) is an inherited skin fragility disorder caused by mutations in keratin intermediate filament proteins. While discoveries of these mutations have increased understanding of the role of keratins and other intermediate filaments in epithelial tissues, progress towards the development of therapy for these disorders is much slower.. Cell culture model systems that display these structural defects are needed for analysis of the cellular consequences of the mutations and to enable possible therapeutic strategies to be developed. Our aim was to generate immortalized cell lines as such model systems for the study of EBS.. We generated a series of stable cell lines expressing EBS-associated keratin mutations, by immortalizing keratinocytes from EBS-affected skin biopsies with either simian virus 40 (SV40) T antigen or human papillomavirus 16 (HPV16) E6/E7, and assessed their keratin expression (by immunofluorescence), proliferation rates and migratory behaviour (in outgrowth and scratch wound assays).. Clonal immortalized keratinocyte cell lines KEB-1, KEB-2, KEB-3 (using SV40 T antigen) and KEB-4, KEB-7 and NEB-1 (using HPV16 E6/E7) were established. These include two lines from a single individual with Weber-Cockayne EBS (i.e. KEB-3 and KEB-4, mutation K14 V270M), and three cell lines from a second family, two from siblings carrying the same mutation (KEB-1, KEB-2 lines from Dowling-Meara EBS, mutation K5 E475G) and one from an unaffected relative (NEB-1). The sixth cell line (KEB-7), with a previously unreported severe mutation (K14 R125P), was the only one to show keratin aggregates in resting conditions. Despite variations in the immortalization procedure, there was no significant difference between cell lines in keratin expression, outgrowth capabilities or response to transient heat shock. However, cell migration, as measured by speed of scratch wound closure, was significantly faster in cells with severe EBS mutations.. These cell lines provide useful culture systems in which to assess aspects of EBS-induced cell changes. The faster migration after scratch wounding of the EBS keratinocytes may be a consequence of the known upregulation of stress-activated kinase pathways in these cells.

Topics: Cell Division; Cell Line; Cell Movement; Cell Transformation, Viral; Child, Preschool; DNA Mutational Analysis; Epidermolysis Bullosa Simplex; Hot Temperature; Humans; Intermediate Filaments; Keratinocytes; Keratins; Mutation; Papillomaviridae; Simian virus 40; Wound Healing

Clusterin gene expression is potently induced in experimental models in which apoptosis is activated, such as rat prostate involution following castration. Nevertheless, its precise physiological role has not yet been established, and both anti-apoptotic and pro-apoptotic functions have been suggested for this gene. Clusterin expression level depends on cell proliferation state, and we recently showed that its over-expression inhibited cell cycle progression of SV40-immortalized human prostate epithelial cells PNT2 and PNT1a. Here we studied clusterin expression in PNT1a cells subjected to serum-starvation with the aim of defining clusterin early molecular changes following apoptosis induction. Under serum-starvation conditions, decreased growth rate, slow rounding-up of cells, cell detachment, and formation of apoptotic bodies indicative of anoikis (detachment-induced apoptosis) were preceded by significant downregulation of 70 kDa clusterin precursor and upregulation of 45-40 kDa isoforms. On the 8th day of serum-free culturing, only the higher molecular weight protein-band of about 45 kDa was clearly induced and accumulated in detached cells and apoptotic bodies in which PARP was activated. Anoikis was preceded by induction and transloction of a 45-kDa clusterin isoform to the nucleus. Thus, nuclear targeting of a specific 45-kDa isoform of clusterin appeared to be an early and specific molecular signal triggering anoikis-death. Considering also that clusterin is downregulated during prostate cancer onset and progression, and that its upregulation has inhibited DNA synthesis and cell cycle progression of immortalized human prostate epithelial cells, we suggest that clusterin might be a new anti-oncogene in the prostate.

Topics: Active Transport, Cell Nucleus; Apoptosis; Cell Division; Cell Line, Tumor; Cell Nucleus; Cell Transformation, Viral; Clusterin; Culture Media, Serum-Free; Epithelial Cells; Gene Expression Regulation, Neoplastic; Glycoproteins; Humans; Keratins; Kinetics; Male; Molecular Chaperones; Prostatic Neoplasms; Protein Isoforms; Simian virus 40

To determine the effect of dilute alcohol on human corneal epithelial cellular morphology and viability. Dilute alcohol is used for epithelial removal during photorefractive keratectomy (PRK) and laser subepithelial keratomileusis (LASEK).. Corneal epithelial sheets harvested from human eyes after alcohol application during PRK were examined by light and electron microscopy (specimens I-IV). In addition, tissue cultures of human epithelial sheets were monitored for epithelial migration and attachment (specimens V-VII). To determine the effect of dilute alcohol on epithelial cell viability, simian virus (SV)40-immortalized human corneal epithelial cells were exposed to dilute alcohol in distilled water (EtOH-H2O) or to keratinocyte serum-free medium (EtOH-KSFM) for incubation periods of 20 to 45 seconds and concentrations of 10% to 70%. Cell membrane permeability and intracellular esterase activity were analyzed by calcein-acetoxymethyl ester (AM)/ethidium homodimer assay. TdT-mediated dUTP nick-end labeling (TUNEL) assay was used to detect apoptotic cells at 0, 8,12, 24, and 72 hours.. Electron microscopy showed varying degrees of basement membrane alterations after alcohol application, including disruptions, discontinuities, irregularities, and duplication (specimens I-IV). Cellular destruction and vacuolization of basal epithelial cells associated with absent basement membrane were also observed (specimen III). One of three cultured epithelial sheets showed attachment and outgrowth in the tissue culture until day 15 (specimen V). Twenty-second exposure of cultured immortalized human cells to various concentrations of EtOH-H2O showed significant reduction of viable cells when EtOH-H2O concentration exceeded 25% (P = 0.005). Increasing the duration of application of 20% EtOH-H2O beyond 30 seconds resulted in a significant reduction in viable cells (69.69% +/- 16.34% at 30 seconds compared with 2.14% +/- 2.29%, 10.45% +/- 7.11%, and 11.09% +/- 15.73% at 35, 40, and 45 seconds, respectively; P = 0.01). TUNEL assay of cultured human corneal epithelial cells exposed to 20% EtOH-H(2)O for 20 and 40 seconds showed maximal labeling at 24 hours (58.05% +/- 33.10%) and 8 hours (94.12% +/- 1.21%), respectively. Exposure to 20% EtOH-KSFM for 20 and 40 seconds resulted in substantially lower TUNEL positivity (3.51% +/- 0.20% at 24 hours and 7.11% +/- 0.49% at 8 hours).. The viability and electron microscopic findings in the basement membrane zone showed significant variation after treatment of the epithelium in vivo with dilute alcohol. The application of dilute alcohol on the monolayer of cultured corneal epithelial cells resulted in increasing cell death in a dose- and time-dependent manner.

Topics: Actins; Apoptosis; Basement Membrane; Cell Membrane Permeability; Cell Survival; Cell Transformation, Viral; Cells, Cultured; Collagen Type VIII; Dose-Response Relationship, Drug; Epithelium, Corneal; Esterases; Ethanol; Fluoresceins; Fluorescent Antibody Technique, Indirect; Fluorescent Dyes; Humans; In Situ Nick-End Labeling; Keratins; Simian virus 40; Time Factors; Vimentin

The primary human urethral epithelial cells developed by our laboratory have been immortalized by transduction with a retroviral vector expressing the human papillomavirus E6E7 oncogenes. Analysis of telomerase expression and comparison to that in primary cells revealed detectable levels in the transduced human urethral epithelial cells. Immortalized urethral cells could be passaged over 20 times. Immunofluorescence microscopy studies showed that the immortalized cells were phenotypically similar and responded to gonococcal infection similarly to primary cells. Specifically, positive cytokeratin staining showed that the immortalized cells are keratinocytes; cell surface levels of human asialoglycoprotein receptor increase following gonococcal infection, and, like the primary cells, the immortalized urethral epithelial cells are CD14 negative. Using enzyme-linked immunosorbent assay, we found that interleukin-6 (IL-6) and IL-8 levels in primary urethral epithelial cell supernatants increase after challenge with N. gonorrhoeae. Likewise, the immortalized urethral epithelial cells produced higher levels of IL-6 and IL-8 cytokines in response to gonococcal infection. Cells challenged with a gonococcal lipid A msbB mutant produced reduced IL-6 and IL-8 levels when compared to the parent strain. Additionally, these data suggest that the 1291 msbB lipooligosaccharide may suppress cytokine induction.

Topics: Asialoglycoprotein Receptor; Cell Transformation, Viral; Cells, Cultured; Cytokines; Epithelial Cells; Genes, Viral; Genetic Vectors; Gonorrhea; Humans; Inflammation Mediators; Interleukin-6; Interleukin-8; Karyotyping; Keratins; Lipopolysaccharide Receptors; Models, Biological; Neisseria gonorrhoeae; Oncogene Proteins, Viral; Papillomavirus E7 Proteins; Phenotype; Receptors, Cell Surface; Retroviridae; Urethra

Colonization of the vaginal introitus by fecal Escherichia coli is thought to be a key initial event leading to acute urinary tract infection, yet the mannosylated receptor for type 1 pili on the squamous epithelium of vaginal mucosa is unknown. E. coli expressing type 1 pili adhered to sections of normal human vaginal epithelium in a gradient with greatest binding in upper cell layers was observed, which suggests that epithelial differentiation influences bacterial binding. Consistent with this observation, bacterial binding was enhanced in vaginal epithelial cultures that were induced to differentiate, and this enhanced bacterial binding was associated with increased K13 expression levels and increased binding of the mannose-specific lectin Galanthus nivalis agglutinin. These results demonstrate that the binding of type 1-piliated E. coli to vaginal epithelial cells correlates with epithelial differentiation and suggest that the vaginal receptor for type 1 pili is up-regulated during differentiation.

Topics: Bacterial Adhesion; Cell Culture Techniques; Cell Differentiation; Cell Line, Transformed; Cell Transformation, Viral; Epithelium; Escherichia coli; Female; Fimbriae, Bacterial; Humans; Keratins; Vagina

Keratin intermediate filaments are heteropolymers composed of type I and type II keratins. Ultraviolet B (UVB) irradiation induces keratin expression by keratinocytes. Using SV40-transformed human keratinocytes (SVHK), we investigated the effect of UVB irradiation on keratin expression. UVB irradiation (10 mJ/cm(2)) increased keratin 5 and keratin 14 mRNAs and proteins without affecting cell viability. Upregulation of keratin 5 and keratin 14 was dependent on the dose of radiation: the effect was observed at 5 mJ/cm(2) and the maximal effect was observed at 10 mJ/cm(2). Higher UVB doses (more than 10 mJ/cm(2)) were cytotoxic. Expression of keratin 1 and keratin 10 was marginal in SVHK and was not affected at either the mRNA or protein level by UVB. The stimulatory effects on keratin 5 and keratin 14 expression were also observed in cultured normal human keratinocytes (NHK) and HaCaT keratinocytes. The tyrosine kinase inhibitor, genistein, and the epidermal growth factor (EGF) receptor inhibitor, AG1429, significantly suppressed the increase in expression of keratin 5 and keratin 14 by SVHK. In contrast, the suppressive effect was not observed with the protein kinase C inhibitor, H-7. Furthermore, pretreatment with neutralizing anti-EGF receptor antibody also suppressed UVB-induced keratin 5 and keratin 14 expression by SVHK, NHK and HaCaT cells. UVB irradiation did not affect the steady-state expression of TGF-alpha by SVHK. Immunoprecipitation and immunohistochemical studies revealed that UVB irradiation induced EGF receptor activation in the absence of EGF and TGF-alpha. These results indicate that UVB increases keratin 5 and keratin 14 expression through direct activation of the EGF receptor in SVHK.

Topics: Cell Line, Transformed; Cell Transformation, Viral; ErbB Receptors; Humans; Keratin-14; Keratin-5; Keratinocytes; Keratins; Simian virus 40; Ultraviolet Rays

The 293 cell line was derived by transformation of primary cultures of human embryonic kidney (HEK) cells with sheared adenovirus (Ad)5 DNA. A combination of immunostaining, immunoblot, and microarray analysis showed that 293 cells express the neurofilament (NF) subunits NF-L, NF-M, NF-H, and a-internexin as well as many other proteins typically found in neurons. Three other independently derived HEK lines, two transformed by Ad5 and one by Ad12, also expressed NFs, as did one human embryonic retinal cell line transformed with Ad5. Two rodent kidney lines transformed with Ad12 were also found to express NF proteins, although several rodent kidney cell lines transformed by Ad5 DNA and three HEK cell lines transformed by the SV40 early region did not express NFs. These results suggest that human Ads preferentially transform human neuronal lineage cells. We also demonstrate that the widely used HEK293 cells have an unexpected relationship to neurons, a finding that may require reinterpretation of many previous studies in which it was assumed that HEK293 cells resembled more typical kidney epithelial cells.

Topics: Adenoviruses, Human; Carrier Proteins; Cell Line; Cell Line, Transformed; Cell Transformation, Viral; Humans; Immunohistochemistry; Intermediate Filament Proteins; Keratins; Neurofilament Proteins; Neurons; RNA, Messenger; Vimentin

In the endeavour to develop a model for studying gene therapy of cancers associated with human papillomaviruses (HPVs), mouse cells were transformed with the HPV type 16 (HPV16) and activated H-ras oncogenes. This was done by cotransfection of plasmid p16HHMo, carrying the HPV16 E6/E7 oncogenes, and plasmid pEJ6.6, carrying the gene coding for human H-ras oncoprotein activated by the G12V mutation, into secondary C57BL/6 mouse kidney cells. An oncogenic cell line, designated MK16/1/IIIABC, was derived. The epithelial origin of the cells was confirmed by their expression of cytokeratins. No MHC class I and class II molecules were detected on the surface of MK16/1/IIIABC cells. Spontaneous metastases were observed in lymphatic nodes and lungs after prolonged growth of MK16/1/IIIABC-induced subcutaneous tumours. Lethally irradiated MK16/1/IIIABC cells induced protection against challenge with 10(5) homologous cells, but not against a higher cell dose (5 x 10(5)). Plasmids p16HHMo and pEJ6.6 were also used for preventive immunization of mice. In comparison with a control group injected with pBR322, they exhibited moderate protection, in terms of prolonged survival, against MK16/1/IIIABC challenge (P < 0.03). These data suggest that MK16/1/IIIABC cells may serve as a model for studying immune reactions against HPV16-associated human tumours.

Topics: Animals; Cell Line; Cell Line, Transformed; Cell Transformation, Viral; DNA, Recombinant; Female; Flow Cytometry; Gene Expression; Histocompatibility Antigens Class I; Histocompatibility Antigens Class II; Humans; Immunoblotting; Immunohistochemistry; Keratins; Male; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms, Experimental; Oncogene Proteins, Viral; Papillomaviridae; Papillomavirus E7 Proteins; Plasmids; ras Proteins; Repressor Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA; Transfection; Tumor Cells, Cultured

Transduction of human papillomavirus type 16 (HPV16) E6/E7 into primary culture of human esophageal keratinocytes using a recombinant adenovirus prolonged the life-span, while untreated cells senesced within 14-16 population doublings (PDLs). Up-regulation of telomerase activity and acquisition of serum-resistant growth were observed in the esophageal keratinocytes with extended life-span between 50 and 100 PDLs, and drastically increased after 100 PDLs. A keratinocyte sample with a polymorphism of Pro/Pro at codon 72 of p53 showed resistance to HPV16 E6/E7-induced life-span-extension and immortalization, in contrast to others with p53 polymorphisms of Arg/Arg or Arg/Pro, which did not. The high efficiency of E6/E7-induction by adenovirus vector also revealed the M1 and M2 stages of keratinocyte immortalization first described in this report.

Topics: Adenoviridae; Calcium; Cell Transformation, Neoplastic; Cell Transformation, Viral; Colony-Forming Units Assay; DNA Primers; Epithelial Cells; Esophagus; Genetic Vectors; Humans; In Situ Hybridization; In Vitro Techniques; Keratins; Microscopy, Phase-Contrast; Oncogene Proteins, Viral; Papillomaviridae; Papillomavirus E7 Proteins; Repressor Proteins; Telomere; Transfection; Tumor Suppressor Protein p53; Up-Regulation

Human oviductal cells stimulate embryo development in vitro partly by the production of embryotrophic glycoproteins. The identity of these glycoproteins is not yet known mainly because oviductal samples are limited and that the cultured parental oviductal cells cannot produce sufficient amount of embryotrophic factors for characterization. In this study, human oviductal epithelial cells (OE) were immortalized by HPV 16 E6/E7 open reading frame (ORF) by retroviral expression. The characteristics of this immortalized cell line (OE-E6/E7) were compared to the parental OE. HPV 16 E6/E7 DNA was found only in OE-E6/E7 but not in OE. Human oviduct-specific glycoprotein, estrogen receptors, and cytokeratin were found in both cell types. Both OE and OE-E6/E7 possessed telomerase activities but the former had much lower activity. OE-E6/E7 also produced glycoproteins with chromatographic behavior similar to the embryotrophic glycoproteins derived from OE. These results showed that OE-E6/E7 retained a number of characteristics of OE. The development of preimplantation mouse embryo was significantly better after coculture with OE-E6/E7 when compared to medium alone culture in term of blastulation rates (52% vs. 32%) and blastocyst diameter (113.0 +/- 2.07 microm vs. 83.9 +/- 5.23 microm). This immortalized cell line can be used as a continuous and stable in vitro system for the study of the oviductal embryotrophic activity. Mol. Reprod. Dev. 59: 400-409, 2001.

Topics: Animals; Cell Line, Transformed; Cell Transformation, Viral; Coculture Techniques; Culture Media, Conditioned; Embryo, Mammalian; Epithelial Cells; Fallopian Tubes; Female; Glycoproteins; Humans; Immunoblotting; Immunohistochemistry; Keratins; Mice; Papillomaviridae; Phenotype; Receptors, Estrogen; Reverse Transcriptase Polymerase Chain Reaction; Telomerase

The Epstein-Barr virus (EBV) is associated with two major human epithelial malignancies, where it is likely to play a role in the malignant phenotype: undifferentiated nasopharyngeal carcinoma (100% of cases) and gastric carcinomas (about 10% of cases). We and others have obtained growth transformation of monkey kidney primary epithelial cells by transfection of viral DNA, especially with the BARF1 gene of EBV (Wei et al., 1997). We now report that the same type of primary epithelial cells can be growth-transformed using EBV particles derived from a nasopharyngeal carcinoma tumor line. Not only can these EBV-infected cells grow over 100 passages, escaping senescence, in contrast to their noninfected counterparts, but they can also survive and proliferate at very low cell density. Several subclones were characterized in terms of viral gene expression. All these clones gave a similar pattern, with detection of EBNA1 and BARF1 proteins but absence of LMP1. CD21, which is the main EBV receptor on B lymphocytes, was not expressed on parental monkey kidney epithelial cells nor on EBV-infected cell clones. This model of epithelial cell transformation will be useful for a better investigation of EBV functions critical for oncogenesis of epithelial cells.

Topics: Animals; Carcinogenicity Tests; Cell Division; Cell Transformation, Viral; Cells, Cultured; Epithelial Cells; Epstein-Barr Virus Nuclear Antigens; Gene Expression; Genes, Viral; Genome, Viral; Haplorhini; HeLa Cells; Herpesvirus 4, Human; Humans; Keratins; Mice; Mice, Nude; Nasopharyngeal Neoplasms; Receptors, Complement 3d; Tumor Cells, Cultured; Viral Matrix Proteins; Viral Proteins

To study the effects of sodium butyrate on proliferation, differentiation and apoptosis of immortalized esophagus epithelial cells.. SHEE, an immortalized human fetal esophageal epithelial cell line induced by HPV18 E6E7, was cultivated in culture flasks and 24-well plates. Two experiment groups of cultured cells were treated with 1 and 5 mmol/L of sodium butyrate respectively for 4 days, and one group of untreated cells set aside as control. The numbers of cloned cells were calculated. The ultra-structure of SHEE cells was examined by transmission electron microscopy (TEM). The cell cycle and number of apoptotic cells were measured by flow cytometry, Ki-67 and cytokeratin of cells were detected by immunohistochemistry method and F-actin of cells labeled with phalloidin was examined by laser confocal scanning microscopy.. Colony formations showed a significant decrease in the 2 experiment groups after 4 days of culture (P < 0.01). In the 1 mmol/L group, the cells at S phase were diminished and arrested at G(0)/G(1) phase. Compared with control group, Ki-67 positive cells were found decreased, while F-actin and cytokeratin were increased. Apoptotic cells in 5 mmol/L group were increased markedly.. Sodium butyrate may induce SHEE cells growth arrest, differentiation and apoptosis. The effects depend on sodium butyrate concentration and time of exposure. Whether it can be used in combination with other anticancer drugs should be further studied.

Topics: Actins; Apoptosis; Butyrates; Cell Cycle; Cell Differentiation; Cell Proliferation; Cell Transformation, Viral; Cells, Cultured; DNA-Binding Proteins; Epithelial Cells; Esophagus; Fetus; Humans; Keratins; Ki-67 Antigen; Oncogene Proteins, Viral; Papillomaviridae

To determine in SV40-immortalized rabbit corneal epithelial cells (RCE), whether there is conservation of parent tissue serum growth-factor-stimulated cytokine receptor activation and downstream intracellular signaling events mediating control of cell cycle progression and differentiation.. Immunostaining and Western blot analysis were used to measure cytokeratin K3 and K12 expression with AE5 and AK12 antibodies. Karyotype analysis was performed based on comparison of the RCE chromosomal complement with its parent tissue. EGF receptor activation was evaluated based on immunochemistry and Western blot analyses of EGF receptor dimerization and phosphorylation. Functional status of EGF receptor was determined through measurements of EGF-induced stimulation of ERK-2 activity, which is a component of the mitogen-activated protein kinase cascade (MAPK). This was done by immunocomplex and kinase assay using anti-ERK antibodies and a specific substrate. EGF-induced increases in proliferation and cell cycle progression were determined based on measurements of [(3)H]-thymidine incorporation, G(2)-specific cyclin B1 expression and cell cycle mapping.. From days 7 to 14, K12 expression increased based on marked rises in the levels of a 55 kD band. At day 14, a 64 kD band also appeared indicative of K3 expression. Karyotype analysis showed that there were no chromosomal losses due to SV-40 transformation. Upon exposure to EGF (5 ng/ml) for 1 min, EGF receptors were activated and formed clusters indicating that autophosphorylation and multimerization of the EGF receptor were occurred. In the presence of serum growth factors or EGF, ERK-2 kinase activity was markedly increased with a bell-shaped time-dependent activation pattern. Cell cycle progression was analyzed in G(1)/S boundary synchronized RCE cells. After releasing the cells into modified Supplemented Hormonal Epithelium Medium containing 10% serum and DMEM/F-12 medium, 80% of the cells had entered the S phase within 2 h. In addition, time dependent changes in [(3)H]-hymidine incorporation over 8 h confirmed RCE passage through the G(1)/S checkpoint. There were more RCE cells entered the G(2)/M phase of cell cycle in the 6-8 h interval after their release. Another indication of cell cycle progression into the G(2)/M phase was that at 8-10 h cyclin B(1) expression reached its maximal level.. RCE in passage number 12-20 are a physiologically relevant model for studies on growth factor receptor mediated control of cell cycle progression and differentiation in its parent tissue as each of these phenomena were conserved: 1) EGF-induced EGF receptor activation; 2) EGF-activated ERK signaling; 3) expression of cornea-specific differentiation markers; 4) karyotype profile; and 5) cell cycle control and progression.

Topics: Animals; Blotting, Western; Cell Differentiation; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Cyclin B; Cyclin B1; DNA; Epidermal Growth Factor; Epithelium, Corneal; ErbB Receptors; Fluorescent Antibody Technique, Indirect; Karyotyping; Keratins; Mitogen-Activated Protein Kinase 1; Phosphorylation; Rabbits; Signal Transduction; Simian virus 40

The process by which fetal lung epithelial cells differentiate into type 1 and type 2 cell is largely unknown. In order to study lung epithelial cell proliferation and differentiation we have infected 20-day fetal lung epithelial cells with a retrovirus carrying a temperature-sensitive SV40 T antigen (T Ag) and isolated several immortalized fetal epithelial cell lines. Cell line 20-3 has characteristics of lung epithelial cells including the presence of distinct lamellar bodies, tight junctions, keratin 8 and 18 mRNA, HFH8, and T1 alpha mRNA and low levels of surfactant protein A mRNA. At 33 degrees C 20-3 grows with a doubling time of 21 h. At 40 degrees C the majority of cells cease to proliferate. Growth arrest is accompanied by significant morphological changes including an increase in cell size, transition to a squamous phenotype that resembles type 1 cells, and an increase in the number of multinucleated cells within the population. Greater than 95% of the cells incorporate [3H]thymidine into DNA at 33 degrees C whereas at 40 degrees C label incorporation drops to less than 20%. When shifted down to 33 degrees C 40% of the cells remain terminally growth arrested. In addition, cells plated at 40 degrees C have a reduced ability to form colonies when replated at 33 degrees C. Treatment with TGF-beta increases the percentage of cells that terminally growth arrest to greater than 80%. Growth arrest is accompanied by an increase in the levels of c-jun, jun D, cyclin D1, C/EBP-beta, transglutaminase type II, and retinoblastoma (Rb) mRNA and an induction of p105, the hypophosphorylated, growth regulatory form of Rb. Evaluation of Rb mRNA in fetal lung indicates that it is induced 2.5-fold between 17 and 21 days of gestation. These studies indicate that 20-3 terminally growth arrests in culture at the nonpermissive temperature and that it may be useful in studying changes in gene expression that accompany terminal growth arrest during lung development.

Topics: Animals; Antigens, Polyomavirus Transforming; Cell Differentiation; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Colony-Forming Units Assay; Epithelial Cells; Gene Expression Regulation, Developmental; Genes, Retinoblastoma; Genetic Vectors; Keratins; Lung; Mice; Rats; Rats, Sprague-Dawley; Recombinant Fusion Proteins; Retinoblastoma Protein; Retroviridae; RNA, Messenger; Simian virus 40; Temperature; Transcription Factors; Transforming Growth Factor beta

AP-1 transactivation appears to be required for mouse JB6 cell neoplastic transformation induced by the tumor promoter TPA or epidermal growth factor (EGF). Exposure to AP-1 transrepressing retinoids and glucocorticoids and expression of a dominant negative c-jun (TAM67) blocked tumor promoter-induced AP-1 transactivation and neoplastic transformation. The aim of the present study was to extend the inquiry of the role of AP-1 and other transcription factors to human neoplastic progression. Expression of human papillomavirus (HPV) 16 or 18 E6 and E7 immortalizes human keratinocytes and inhibits serum/calcium-stimulated differentiation. Further transformation by v-fos co-expression renders these keratinocytes tumorigenic in nude mice. We have analysed two series of E6/E7 immortalized human keratinocyte cell lines that show progressing phenotypes ranging from differentiation sensitive to anchorage-independent to tumorigenic in nude mice. We analysed the activities of AP-1 and NF-kappaB which may 'cross-talk'. Both DNA binding and transactivation of AP-1 and NF-kappaB transcription factors showed elevation in the anchorage-independent (16RH) and tumorigenic (18 v-fos) keratinocyte lines compared to the less progressed but immortalized cell lines. HPV E7 was expressed at a constant level shown by quantitative RT-PCR in both the more and the less progressed lines, indicating that E7 is not the factor limiting this progression. Blocked shift/supershift analysis indicates that Fos family member proteins especially Fra-1 and Fra-2 are related to progression and no changes found in the Jun family member proteins although they are present in the AP-1/DNA binding complex. When a dominant negative mutant c-jun driven by a human keratin 14 promoter was co-transfected with AP-1 or NF-kappaB reporters, both AP-1 and NF-kappaB activities were suppressed in the more progressed cell lines 16RH and 18 v-fos but not in the less progressed 16RL or 18 cell lines. Overexpression of the same dominant negative c-jun did not inhibit p53 dependent reporter transactivation, indicating the specificity of inhibition of AP-1 and NF-kappaB transactivation in the HPV-immortalized cells. Stable transfectants of this mutant c-jun in the two more progressed cell lines 16RH and 18 v-fos showed reduced AP-1 and NF-kappaB activation and reduced anchorage-independent growth. Together, these results indicate that activation of AP-1, NF-kappaB or both may contribute to neoplastic progression in HP

Topics: Cell Division; Cell Line; Cell Transformation, Viral; DNA-Binding Proteins; Fos-Related Antigen-2; Humans; Keratin-14; Keratinocytes; Keratins; Mutagenesis; NF-kappa B; Oncogene Proteins v-fos; Oncogene Proteins, Viral; Papillomaviridae; Papillomavirus E7 Proteins; Phenotype; Promoter Regions, Genetic; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Repressor Proteins; Transcription Factor AP-1; Transcription Factors; Transcriptional Activation; Transfection

Keratin 12 (K12) is a cornea epithelial cell-specific intermediate filament component. To provide a better understanding of its expression, it is necessary to identify and characterize the promoter of Krt1.12 gene.. The 2.5-kb DNA 5' to Krt1.12 gene was sequenced. Krt1.12 promoter-beta-gal DNA constructs were prepared and used in vivo to transfect rabbit corneas, conjunctivas, and skin by particle-mediated gene transfer (Gene Gun). In vitro, the DNA constructs were transfected into cultured T-antigen-transformed rabbit corneal epithelial (RCE-T) cells and human fibrosarcoma HT-1080 fibroblasts with lipofectamine. The promoter activity was assessed by measuring beta-gal (beta-galactosidase) activity using histochemical staining with 5-Bromo-4-chloro-3-indolyl-beta-D-galactoside and enzyme assay with o-nitrophenyl beta-D-galactopyranoside.. There are four Pax-6 pair box binding elements found between -910 and -2000 bp 5'-flanking the transcription initiation site of the Krt1.12 gene. None of promoter constricts can be expressed by HT-1080 cells. Cotransfection of Pax-6 cDNA with K12 promoter-beta-gal constructs containing Pax-6 elements results in a fourfold increase of beta-gal activities in RCE-T cells but not HT-1080 fibroblasts. The data of in vivo transfection in the rabbit by Gene Gun indicate that reporter gene constructs containing 0.6-kb and longer DNA fragments 5'-flanking Krt1.12 gene are effectively expressed in corneal, but not conjunctival or epidermal epithelial cells.. The particle-mediated gene transfer is a suitable technique for in vivo delivery of transgenes to corneal epithelial cells. The 2.5-kb DNA fragment 5'-flanking Krt1.12 contains corneal epithelial cell-specific regulatory cis-DNA elements. Pax-6 is a positive transcription factor essential for keratin 12 expression.

Topics: Animals; Antigens, Polyomavirus Transforming; Base Sequence; beta-Galactosidase; Cell Transformation, Viral; Cells, Cultured; Conjunctiva; DNA; DNA-Binding Proteins; Epithelium, Corneal; Eye Proteins; Fibroblasts; Homeodomain Proteins; Humans; Keratins; Molecular Sequence Data; Paired Box Transcription Factors; PAX6 Transcription Factor; Promoter Regions, Genetic; Rabbits; Repressor Proteins; Skin; Transcription Factors; Transfection

We previously reported that the BARF1 (BamH1-A right frame 1) gene product from Epstein-Barr Virus (EBV) may have oncogenic properties since injection into new-born rats of transfected cell lines resulted in the development of BARF1 expressing tumors, which were aggressive in the case of murine fibroblasts and transient in that of human B lymphocytes. As EBV has been associated with nasopharyngeal carcinoma (NPC) and evidence of BARF1 transcription in this cancer was emerging from our biopsy analyses, we examined the effects of BARF1 transfection into primate primary epithelial cells. The expression of the BARF1 open reading frame in primary monkey kidney epithelial cells led us to the establishment of continuously dividing lines. The BARF1 transfectants showed the major characteristics of immortalized cells: morphological change, short cell doubling time, ability to divide at low cell density and continuous growth over 50 passages. Injection of BARF1 transfectants into nude mice did not induce any tumor. Established subclones were shown to be epithelial cells expressing known keratins as well as the BARF1 coded mRNA and protein. This is the first report indicating that expression of the BARF1 gene product in primary epithelial cells may contribute to the establishment of cell lines.

Topics: Animals; Carcinogenicity Tests; Cell Division; Cell Line; Cell Transformation, Viral; Cells, Cultured; Epithelium; Haplorhini; Herpesvirus 4, Human; Keratins; Kidney; Mice; Mice, Nude; Open Reading Frames; Thymidine; Transfection; Viral Proteins

A comparison of the CAT reporter activity of a plasmid which contains the 232 bp epithelial specific enhancer alone with that of plasmids which contain additional sequences from the human papillomavirus type 16 (HPV-16) upstream regulatory region (URR) revealed two markedly different patterns, in an analysis of six human epithelial cell lines. In HeLa, C33A and SiHa, the CAT reporter activities of all the constructs were comparable. In contrast, in CaSki, HK2bE6-E7 and HaCaT we detected very low levels of CAT reporter activity using the constructs with the additional HPV-16 URR sequences. The ability of HPV-16 E2 to transactivate a construct with 2 E2 binding sites also differed markedly and showed the same pattern. Cytokeratin staining revealed a correlation between cytokeratin 10 and 14 expression and the transcriptional differences observed. We also found alterations in the activity of one of the constructs on altering the growth conditions of the HaCaT cell line.

Topics: Cell Differentiation; Cell Transformation, Viral; Enhancer Elements, Genetic; Epithelium; Gene Expression; Gene Expression Regulation, Viral; Histocytochemistry; Humans; Keratins; Papillomaviridae; Transcription, Genetic; Transcriptional Activation

Human papillomaviruses (HPVs) and cigarette smoking are epidemiologically associated with cervical cancer. We recently found that HEN-16 and HEN-16-2 HPV type 16-immortalized endocervical cells form tumors after treatment with cigarette smoke condensate and derived 2 tumor cell line cultures, HEN-16T and HEN-16-2T, respectively. Here, we examine the molecular pathologic effect of tumorigenesis. HEN-16T and HEN-16-2T exhibit unchanged status and expression of integrated HPV 16 DNA. However, the expression of the cytokeratin CK7 and CK13 endocervical cell markers is more homogeneous in monolayer and organotypic raft cultures after tumorigenesis. For the effect of retinoic acid on monolayers for growth inhibition, HEN-16T were significantly less sensitive than the normal and immortalized non-tumorigenic cells. HEN-16-2T were completely resistant. Moreover, the rafts from both tumorigenic cell line cultures were resistant to retinoic acid and continued to display thick rafts and homogeneous severe dysplasia/carcinoma in situ. In contrast, the non-malignant HEN-16 and HEN-16-2 rafts were thinner, and treatment with retinoic acid blocked the formation of severe dysplasia, reconstructing an epithelium resembling that of the normal endocervix. Our results support the significance of non-viral factors in the mechanism by which cigarette smoking induces tumorigenesis in the late stages of HPV-initiated progression to cervical cancer. Importantly, our data indicate that the sensitivity to retinoic acid of the HPV-containing endocervical cells is lost following tumorigenesis in vitro and possibly in women.

Topics: Cell Division; Cell Line, Transformed; Cell Transformation, Neoplastic; Cell Transformation, Viral; DNA, Viral; Drug Resistance; Female; Humans; Keratins; Keratolytic Agents; Papillomaviridae; Tretinoin; Uterine Cervical Neoplasms

Polyoma virus middle T antigen (mT) transforms the T51B cell line and induces the loss of the cytokeratin 8 and 14 pair (CK8/CK14) present in these rat nonparenchymal liver epithelial cells (LECs), because of the selective down-regulation of CK14 gene expression. To identify the initial steps of the mT-induced signaling pathway(s) leading to this inhibition, T51B cells were transfected with vectors encoding the NG59, dl23, and 248M mT mutants, which are known to interact in a differential manner with c-Src, P13-kinase, and Shc. Immunofluorescence microscopy and Northern blot analysis showed a loss of cytokeratins in dl23 or 248M but not in NG59 mT mutant-containing cells. An in vitro kinase assay demonstrated that only the dl23 and 248M mT mutants could associate with c-Src. This c-Src-mediated action of mT on CK14 gene expression was further confirmed by adding the v-src gene product in T51B cells. The assessment of the transforming capacity of the mT mutants demonstrated that the NG59 and dl23 mT mutants were nontransformant, whereas the 248M mT mutant expressed an appreciable transforming activity. These results show that the down-regulation of CK14 gene expression by mT in the LEC line T51B is dependent on the association with the c-Src tyrosine kinase, but interestingly, this c-Src-mediated action of mT can occur in the absence of transformation. Furthermore, when coupled with recent data on the plasticity of LECs, the present findings provide the first essential element in our definition of the signaling pathway(s) that link growth/differentiation events with CK gene regulation in typical simple epithelial cells.

Topics: Animals; Antigens, Polyomavirus Transforming; Cell Line; Cell Transformation, Viral; Down-Regulation; Epithelial Cells; Epithelium; Gene Expression Regulation, Viral; Genes, src; Genetic Vectors; Keratins; Liver; Mutation; Rats; Rats, Inbred F344; Transfection

Gene expression of human papillomavirus type 16 (HPV-16) and other HPV types is epithelial specific. Specificity is brought about by synergism between several different transcription factors that seem to occur ubiquitously but differ qualitatively and quantitatively between cells in which HPV genomes are transcriptionally active or inactive. Here, we report on the contribution to this combinatorial mechanism by the activator Sp1 and the related antagonist Sp3, both of which can bind a single site at the E6 promoter of all genital HPVs. In the Sp-factor-free background of Drosophila cells, Sp1 activates HPV-16 transcription, while Sp3 fails to do so and even inhibits the activation by Sp1. The same differential activation occurs in the case of promoters of the epithelial-specific cellular genes encoding keratin 18 and E-cadherin. All cell types that we examined contain similar amounts of Sp3 factor. In contrast, Sp1 levels, determined by supershifts and Western blots, are higher in several human epithelial cell lines that support HPV transcription than in human fibroblasts, liver, and muscle cells. This suggests that cell-type differential transcription is regulated by Sp1 and Sp3. In primary keratinocytes, Sp3 levels exceed those of Sp1. This ratio became inverted after differentiating these cells in high calcium, or methyl cellulose containing medium. The simultaneous transcriptional stimulation of the HPV promoter points to a role of the Sp1-Sp3 antagonism during a differentiation of stratified epithelia in vivo, as these culture techniques mimick this process in vitro. Transformation in vivo or in vitro seems to override these cell-type-specific controls and leads to a general increase of Sp1 activity.

Topics: Animals; Cadherins; Cell Differentiation; Cell Line; Cell Transformation, Viral; DNA-Binding Proteins; DNA, Viral; Drosophila; Epithelial Cells; Fibroblasts; Gene Expression Regulation, Viral; HeLa Cells; Humans; Keratinocytes; Keratins; Papillomaviridae; Promoter Regions, Genetic; Sp1 Transcription Factor; Sp3 Transcription Factor; Transcription Factors; Transcription, Genetic; Tumor Cells, Cultured; Up-Regulation

Retinoids are important regulators of human papillomavirus (HPV)-immortalized cervical epithelial cell differentiation and have been successfully used in the treatment of HPV-involved cervical cancer. In the present study, we examine the effects of a series of natural and synthetic retinoids on differentiation and proliferation of HPV-16-positive lines, ECE16-1 and CaSki. Retinoic acid receptor alpha (RAR alpha), RAR gamma, and retinoid X receptor alpha (RXR alpha) are the major retinoid receptor subtypes expressed when ECE16-1 cells are grown in retinoid-free medium. Our results indicate that ligands that interact with RARs only or both RARs and RXRs, including all-trans-retinoic acid (all-trans-RA), 9-cis-retinoic acid (9-cis-RA), 13-cis-retinoic acid (13-cis-RA), and several synthetic retinoids, suppress ECE16-1 cell proliferation, regulate expression of the retinoid-responsive differentiation marker cytokeratin K5, and increase RAR beta mRNA levels. In contrast, ligands that specifically interact with RXRs do not suppress proliferation and are less efficient regulators of gene expression. CaSki cells express greatly reduced RAR and RXR levels compared to ECE16-1 cells. However, both RAR- and RXR-specific ligands increase CaSki number by > or = 20%. In addition, RXR-specific ligands suppress cytokeratin K5 mRNA levels slightly, compared to RAR-specific ligands that strongly suppress K5 mRNA levels. We also compare the effects of these agents on the proliferation of other cervical cell lines, including ECE16-D2, ME180, and SiHa cells. ECE16-D2 and ME180 cells are growth suppressed by RAR-specific, but not RXR-specific, retinoids. SiHa cells are not responsive to either class of retinoid. Our results indicate that: (a) the response of different human cervical cell lines varies following treatment with receptor type-specific retinoids; and (b) the relationship between retinoid regulation of proliferation and differentiation can be uncoupled.

Topics: Cell Differentiation; Cell Division; Cell Transformation, Viral; Female; Humans; Keratins; Papillomaviridae; Receptors, Retinoic Acid; Retinoid X Receptors; Retinoids; RNA, Messenger; Transcription Factors; Tumor Cells, Cultured; Uterine Cervical Neoplasms

The authors attempted to immortalize human corneal epithelial cells; it is difficult to propagate primary human corneal epithelial cells because of scarcity of available tissue. However, cell immortalization by virus is always accompanied by shedding of free virus. The current study was performed to establish a cell line that produces no free viral particle.. Primary cultured human corneal epithelial cells were infected with a recombinant sv40-adenovirus vector and were cloned three times to obtain a continuously growing cell line. Morphologic, cytologic, and biochemical characteristics of this cell line were analyzed.. This cell line continued to grow for more than 400 generations, exhibiting a cobblestone-like appearance similar to normal corneal epithelial cells in culture. Transmission electron microscopy showed the evidence for the characteristic features of epithelial cells, including desmosome formation and development of microvilli. It expressed cornea-specific, 64-kD cytokeratin in addition to five major insoluble proteins. By enzymatic analysis using NADP as a coenzyme and a gas chromatograph mass spectrometer, this cell line was found to possess 8.71 IU/mg protein of aldehydedehydrogenase activity. When this cell line was grown at air-liquid interface on collagen type I gel, it differentiated in a multilayered fashion.. The authors have established an SV40-immortalized human corneal epithelial cell line with properties similar to normal corneal epithelial cells.

Topics: Aldehyde Dehydrogenase; Antigens, Polyomavirus Transforming; Cell Differentiation; Cell Division; Cell Line; Cell Transformation, Viral; Cells, Cultured; Cornea; Electrophoresis, Polyacrylamide Gel; Epithelial Cells; Epithelium; Female; Fluorescent Antibody Technique; Humans; Keratins; Middle Aged; Recombinant Proteins; Simian virus 40

We introduced the origin-defective SV40 early gene into cultured human oesophageal epithelial cells by infection of a recombinant SV40 adenovirus vector. The virus-infected cells formed colonies 3-4 weeks after infection in medium containing fetal calf serum. When the cells derived from 'serum-resistant' colonies were then maintained in the serum-free medium with a low calcium ion concentration, some of them passed the cell crisis and kept growing for over 12 months. These cells, regarded as immortalised cells, resembled the primarily cultured oesophageal epithelial cells in morphology and had some of their original characteristics. Treatment of the cells with a high calcium concentration induced phenotypic changes. These cells still responded to transforming growth factor beta. When the immortalised cells were injected into severe combined immunodeficient mice, they transiently formed epithelial cysts, although the typical differentiation pattern of the oesophageal epithelium was not observed. These cysts regressed within 2 months without development into tumours. The results indicated that human oesophageal epithelial cells were reproducibly immortalised by infection with a recombinant SV40 adenovirus vector at relatively high efficiency. The immortalised cells should be useful in studies on oesophageal carcinogenesis and in assessing the cooperative effects with other oncogene products or carcinogens.

Topics: Animals; Antigens, Polyomavirus Transforming; Cell Line, Transformed; Cell Transformation, Viral; Cells, Cultured; Cysts; Defective Viruses; DNA Replication; Epithelial Cells; Epithelium; Esophagus; Genes, Viral; Genetic Vectors; Humans; Immunohistochemistry; Keratins; Mice; Mice, SCID; Replication Origin; Simian virus 40; Transforming Growth Factor beta; Transplantation, Heterologous

Thirty endometrial biopsies were cultured in order to separate stromal and epithelial cells. Using epidermal growth factor (EGF), cortisol, cholera toxin, insulin with 5% horse serum for epithelial cells or a medium with 20% fetal calf serum for stromal cells, we could specifically enrich endometrial culture in epithelial or stromal cells and culture them for 1 or 2 months. These cultures retained the phenotypic characteristics of epithelial (cytokeratins, mucin HMFG 1) and stromal (vimentin, smooth muscle actin, desmin) lineage by immunostaining analysis. Epithelial and stromal cultures from one individual were respectively immortalized by the SV 40 large T antigen. The immortalized cell lines kept the phenotype of the normal cells from which they derived.

Topics: Actins; Adolescent; Adult; Antigens, Polyomavirus Transforming; Biomarkers; Cell Division; Cell Line, Transformed; Cell Separation; Cell Transformation, Viral; Cells, Cultured; Desmin; Endometrium; Epithelial Cells; Epithelium; Female; Growth Substances; Humans; Immunohistochemistry; Keratins; Menstrual Cycle; Middle Aged; Mucins; Phenotype; Recombinant Proteins; Simian virus 40; Transfection; Uterine Diseases; Vimentin

To determine whether human papillomavirus (HPV) 18 has a role in the development of adenocarcinoma from human endo- or ectocervical cells.. Secondary cultures of human endo- and ectocervical cells were assayed for immortalization by HPV 18 DNA using lipofection. The effects of immortalization on the patterns of cytokeratin expression were determined by indirect immunofluorescence using monoclonal antibodies. The differentiation phenotype of the immortalized cells was investigated by a modified in vivo implantation system.. Both endo- and ectocervical cells were immortalized by HPV 18. The immortalized cells contained integrated HPV 18 DNA and expressed E6-E7 RNA. The immortalized endocervical cells had a cytokeratin phenotype characteristic of adenocarcinoma, whereas the immortalized ectocervical cells retained a distinct cytokeratin expression pattern of normal parental cells. In an in vivo implantation system, endocervical cells formed a lesion resembling severe dysplasia or carcinoma in situ, whereas ectocervical cells developed into a lesion resembling mild dysplasia. Both cell lines were nontumorigenic in nude mice.. Both endo- and ectocervical cells are targets for immortalization by HPV 18. Based on cytokeratin expression patterns, immortalized endocervical cells, but not ectocervical cells, may be useful as a model for premalignant lesions that progress into adenocarcinoma.

Topics: Adenocarcinoma; Animals; Blotting, Northern; Blotting, Southern; Cell Line, Transformed; Cell Transformation, Viral; Cervix Uteri; DNA, Viral; Female; Fluorescent Antibody Technique; Gene Expression; Humans; Keratins; Mice; Mice, Nude; Papillomaviridae; Phenotype; Tumor Cells, Cultured; Uterine Cervical Neoplasms

The profile of keratin expression in benign warts from various cutaneous and mucosal sites along with dysplastic warts and squamous cell carcinomas has been examined using a panel of monospecific antibodies to epithelial keratins. Viral warts and verrucous keratoses from immunosuppressed renal transplant recipients show a spectrum of squamous atypia from benign lesions, from minimal changes to full thickness dysplasia. Changes associated with malignancy include loss of differentiation-specific keratins 1 and 10 together with expansion of basal cell epitopes and inappropriate expression of simple epithelial keratins 8, 18, and 19 in advanced squamous cell carcinoma. This late expression of keratins 8 and 18 contrasts with early expression of keratin 17 in all dysplastic lesions examined. Keratin 17 is found suprabasally in hyperproliferative lesions, including benign warts, but marked basal plus suprabasal expression is seen increasingly in malignantly transformed epidermis. These findings were not specific to immunosuppression, as shown by identical findings in control squamous cell carcinoma from nonimmunosuppressed individuals. Keratin 17 expression may prove prognostically helpful when assessing dysplasia in epidermal tumors.

Topics: Biomarkers; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Cell Transformation, Viral; Condylomata Acuminata; Epithelium; Female; Humans; Immunohistochemistry; Keratins; Skin; Skin Diseases; Skin Neoplasms; Warts

The thymic stromal network is complex and heterogeneous, containing thymic epithelial cells which are thought to play an important role during T-cell development and thymic fibroblasts which role is less defined. We herein present a phenotypic and functional comparison between defined thymic stromal cell populations. We transfected SV40 ori- into fetal and postnatal thymic stromal cell cultures and obtained SV40-immortalized clones of epithelial and fibroblastic nature as demonstrated by expression of intracellular keratin. These various clones were characterized in detail and compared to their untransfected bulk culture counterparts for phenotype, cytokine gene expression and cytokine production. All the different thymic stromal cells examined, constitutively expressed ICAM-1, LFA-3, MHC class I antigens, CD44, and the genes coding for IL-7, SCF and TGF-beta, but not TNF-alpha. After IL-1 stimulation, epithelial cells seemed to produce more GM-CSF than fibroblasts, and that trend was also seen for IL-6 secretion. SV40 cells were also regulated by IFN-gamma which induced MHC class II antigens and inhibited the IL-1 induced GM-CSF production. SV40 cells differed from their untransfected counterparts by an atypical expression of CD40 and lacked constitutive IL-1 alpha gene expression. We isolated clones with distinct properties, 24SV48, a highly proliferative CD34 positive TEC secreting low levels of GM-CSF and lacking constitutive IL-1 alpha and beta gene expression, and CT1SV93, an epithelial clone of postnatal origin with a high IL-1-induced cytokine production. In spite of differences with untransfected bulk cultures, the various SV40 immortalized clones may represent useful tools to further study the human thymic stroma.

Topics: Antigens, Surface; Base Sequence; Cell Adhesion Molecules; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Cytokines; Epithelium; Fibroblasts; Gene Expression Regulation; Humans; Infant; Keratins; Molecular Sequence Data; Phenotype; Simian virus 40; Thymus Gland; Transfection

We have examined intrinsic and external factors that influence human papillomavirus type 16 (HPV-16)-mediated immortalization of oral keratinocytes. The efficiency with which HPV can immortalize human oral keratinocytes was quantified and a considerable difference in the transfection and immortalization competence of the cells was detected. The ability of HPV-16 to immortalize oral cells appeared to be linked to the age of the culture upon transfection. The addition of dexamethasone to the transfected cultures increased the efficiency of immortalization, possibly indicating a role for a critical level of HPV gene expression in initial outgrowth of immortalized colonies. We also document in detail the changes in the oral keratinocyte induced by HPV-16 immortalization. These include alterations associated with crisis and feeder independence as well as basic changes in keratin expression and differentiation.

Topics: Cell Differentiation; Cell Division; Cell Transformation, Viral; Cells, Cultured; Dexamethasone; Humans; In Vitro Techniques; Keratinocytes; Keratins; Mouth Mucosa; Papillomaviridae; Transfection

A transformed cell line (HE-IS) was established by transient supertransfection of a SV40-transformed human epidermal cell culture (HE-SL) (R. T. Su and Y.-C. Chang, 1989, Exp. Cell Res. 180, 117-133) with a recombinant plasmid containing an entire Harvey murine sarcoma virus DNA. HE-IS cells showed morphological alterations and less stringent growth requirements in a defined medium. A variant line (HE-TC), selected later from the HE-IS cells after a prolonged maintenance in serum-containing Dulbecco's minimal essential medium (DMEM), was found to be able to grow in either defined or serum-containing medium. Neither HE-IS nor HE-TC cells were able to form colonies in soft agar or induce tumors in athymic mice when inoculated subcutaneously. When grown in defined medium, all transformed cells (HE-SL, HE-IS, HE-TC) revealed a similar keratin pattern as analyzed by two-dimensional gel electrophoresis. However, significant reduction of keratins (notably K5) was detected in HE-TC cells maintained in serum-containing DMEM. The keratin pattern appeared to be regulated by the growth environment. Because of their nontumorigenic characteristics and defined growth properties, these transformed keratinocytes are likely to provide a suitable model system for examining the regulation of cytoskeleton protein synthesis.

Topics: Cell Division; Cell Transformation, Viral; Electrophoresis, Gel, Two-Dimensional; Humans; In Vitro Techniques; Keratins; Sarcoma Viruses, Murine; Simian virus 40; Transfection

Cultured corneal epithelial cell is detrimental because of its short life span and its heterogeneity. We have tried to establish an immortalized epithelial cell line.. Primary cultured rabbit corneal epithelial cells were infected with a recombinant SV40-adenovirus vector and were cloned three times.. The immortalized cell continued to grow by more than 400 generations through 100 passages. SV40-associated large T antigen was demonstrable on the nuclear membrane of these immortalized cells by immunofluorescence technique. This cell line exhibited a similar cobblestone-like appearance as normal corneal epithelial cells. Transmission electron microscopy showed a line of evidence for stratification, including desmosome formation and microvilli development at the superficial cell layer. As the culture grew, these cells began to express cornea-specific 64 kD cytokeratins. In contrast to cultured normal corneal epithelial cells, this cell line had a good proliferative ability after a long-term storage in liquid nitrogen.. Because this particular cell line shares properties consistent with normal corneal epithelial cells and is easy to handle in vitro, it may serve as a useful tool in corneal epithelial research.

Topics: Animals; Antigens, Polyomavirus Transforming; Cell Division; Cell Line; Cell Transformation, Viral; Cells, Cultured; Cornea; Electrophoresis, Polyacrylamide Gel; Epithelial Cells; Epithelium; Fluorescent Antibody Technique; Keratins; Male; Mice; Mice, SCID; Rabbits; Recombinant Proteins; Severe Combined Immunodeficiency; Simian virus 40; Skin Neoplasms

Calcium is an important regulator of normal human cervical cell differentiation; however, it is not known whether the calcium responsiveness of the cells would be altered by immortalization with human papillomavirus. In the present study we examine the effects of extracellular calcium on morphology, expression of biochemical markers of cervical cell differentiation, and HPV16 oncogene transcription in an HPV16-immortalized human cervical cell line, ECE16-1. ECE16-1 cells respond to increased calcium with increased levels of mRNA encoding cytokeratin K13, transglutaminase, and involucrin. Dose-response studies indicate that these markers are coordinately regulated and that maximal levels are present at calcium concentrations of > or = 0.4 mM. RNA levels begin to increase within 24 h after cells are shifted to medium containing high calcium and are maximal by 3 days. Protein levels change directly with the change in mRNA, suggesting that mRNA level determines protein concentration; however, transcription runoff experiments indicate that the increased mRNA does not result from new synthesis. Parallel studies indicate that expression of the HPV16 oncogenes, E6 and E7, are not regulated by extracellular calcium. These results are consistent with in vivo experiments showing that in advanced cervical intraepithelial neoplasia, where HPV16 DNA is integrated in host cell DNA, E6/E7 transcript production is not regulated in a differentiation-dependent manner.

Topics: Calcium; Cell Differentiation; Cell Transformation, Viral; Cervix Uteri; Epithelial Cells; Epithelium; Female; Gene Expression Regulation, Viral; Humans; In Vitro Techniques; Keratins; Oncogene Proteins, Viral; Oncogenes; Papillomaviridae; Papillomavirus E7 Proteins; Protein Precursors; Repressor Proteins; RNA, Messenger; Transglutaminases; Tumor Virus Infections

To develop an in vitro model of human corneal epithelium that can be propagated in serum-free medium that is tissue specific, species specific, and continuously available.. Primary explant cultures from human cadaver donor corneas were generated and subsequently infected with Adeno 12-SV40 (Ad12-SV40) hybrid virus or transfected with plasmid RSV-T.. Several lines of human corneal epithelial cells with extended life span were developed and characterized. Propagation of both primary cultures and lines with extended life span, upon collagen membranes at an air-liquid interface, promoted multilayering, more closely approximating the morphology observed in situ.. In vitro models, using primary cultures of corneal epithelium and lines of corneal epithelial cells with extended life span, retain a variety of phenotypic characteristics and may be used as an adjunct to ocular toxicology studies and as a tool to investigate corneal epithelial cell biology.

Topics: Adenoviruses, Human; Adolescent; Adult; Aged; Aged, 80 and over; Animals; Cell Line; Cell Transformation, Viral; Cells, Cultured; Child; Child, Preschool; Cornea; Culture Media, Serum-Free; Epithelial Cells; Epithelium; Humans; Infant; Infant, Newborn; Karyotyping; Keratins; Middle Aged; Models, Biological; Simian virus 40; Transfection; Vero Cells

Intestinal epithelial cells from the mouse small intestine were immortalized by SV40 large T gene transfer through a murine ecotropic virus. The resulting cell lines expressed the SV40 large T mRNA and exhibited morphological and phenotypic characteristics of normal enterocytes, including intercellular junctions, and expression of cytokeratin, villin, poly-Ig receptor (i.e., secretory component) and vasoactive intestinal peptide receptors. All expressed cell surface major histocompatibility complex class I molecules, but cell surface class II antigens were undetectable. Functional studies on antigen presentation were carried out using the MODE-K cell line established from the mouse duodenum. Interferon-gamma treatment of MODE-K cells resulted in a high level of class II molecule expression, and the ability to process and present native protein antigens to specific CD4+ T-cell hybridomas, via functional class II molecules. These data suggest that the MODE-K cell line is a suitable model for the analysis of intestinal epithelial cell function in mucosal immunity.

Topics: Animals; Antigen-Presenting Cells; Antigens, Viral, Tumor; Cell Division; Cell Line; Cell Transformation, Viral; Epithelial Cells; Epithelium; Gene Expression; Histocompatibility Antigens Class II; Intestine, Small; Keratins; Mice; Microscopy, Electron; Phenotype; Receptors, Vasoactive Intestinal Peptide; RNA, Messenger; Simian virus 40

We have isolated rabbit kidney proximal tubular epithelial cell lines. The selection was based on their ability to form confluent monolayers on porous supports and to maintain receptor-mediated signal transduction and ion transport, characteristic of the proximal tubule. The isolation method consisted of several steps: (1) superficial cortical proximal tubule segments were microdissected and cultured on a matrix-coated porous support until cells formed a confluent monolayer; (2) primary cultures showing hormone-regulated ion transport typical for the proximal tubule were selected and co-cultured with irradiated fibroblasts; and (3) the epithelial cells surviving after several passages were expanded and passaged on porous substrates. Most of the cell lines developed in this manner were obtained by co-culture with irradiated fibroblasts producing a recombinant retrovirus encoding SV40 large T antigen and G418 resistance. However, SV40 T antigen expression was not essential for immortalization, since neither T antigen nor G418 resistance was detected in the isolated cell lines and co-culture with non-producing 3T3 cells gave similar results. One cell line (vEPT) has been characterized in some detail with respect to morphological, biochemical, and ion transport properties. This line forms confluent monolayers with apical microvilli, tight junctions, and convolutions of the basolateral plasma membrane. Once confluent, monolayers maintain conductances of 25 to 32 mS/cm2 for several weeks in culture and possess phlorizin-sensitive short-circuit current (Isc) in glucose containing media, indicative of apical Na(+)-glucose co-transport. vEPT cells also retain receptor and signaling mechanisms for angiotensin II (Ang II). Apical and basal Ang II and 5,6-epoxy-eicosatrienoic acid (5,6-EET) modulate the Isc in a manner similar to primary cultures. The cell lines share with primary cultures expression of the cytokeratins K8, K10/K11, and K19 ("nomenclature" [21]). They also retain several receptor and signal transduction mechanisms. For example, Ang II, arachidonate, bradykinin, 5,6-EET, parathyroid hormone (residues 1 through 34), and purine nucleotides increase cytosolic Ca2+, PTH elevates cAMP levels, and Ang II enhances proximal tubule-specific arachidonic acid metabolism.

Topics: Animals; Antigens, Viral, Tumor; Arachidonic Acid; Calcium; Cell Line; Cell Separation; Cell Transformation, Viral; Cyclic AMP; Cytological Techniques; Epithelial Cells; Epithelium; Ion Transport; Keratins; Kidney Tubules, Proximal; Microscopy, Electron; Rabbits

The purpose of this study was to immortalize porcine endometrial cells and to characterize the transformed cells. Primary porcine endometrial cells were transfected with the plasmid vector (pmk16) containing SV40 DNA using a liposome-mediated method. The viral DNA was from a replication-defective, origin-minus, temperature-sensitive mutant strain (A58). One clone, designated PE-1, has been propagated for over 120 passages. PE-1 cells grown at 33C (33C cells) exhibit spindle-shaped morphology; when cultured at 40C (40C cells), they took on a polygonal or spherical shape. Morphology of 40C cells returned to the spindle shape after culture flasks were shifted back to 33C. During a 2-week period, 33C cells propagated approximately 30-fold faster than 40C cells, whereas protein concentration was higher in 40C cells. Southern blot analysis of PE-1 cells demonstrated successful integration of the ts-SV40 DNA sequence into the porcine endometrial cells, possibly at multiple sites. The presence of cytokeratin on PE-1 cell membranes was shown by immunocytochemical studies, suggesting that the PE-1 cell clone was of epithelial origin. Reverse phase (RP)-HPLC analysis of PE-1 cell extract indicated that the majority of immunoreactive beta-endorphin (ir-BEND) eluted with a hydrophobicity similar to that of synthetic BEND and alpha-N-acetylated BEND (Nac-BEND). These results demonstrate that a porcine endometrial cell line has been established, and that this cell line possesses characteristics of temperature sensitivity in cell morphology, growth rate, and protein synthesis.

Topics: Animals; beta-Endorphin; Blotting, Southern; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Chromatography, High Pressure Liquid; DNA, Viral; Endometrium; Epithelial Cells; Epithelium; Female; Keratins; Phenotype; Simian virus 40; Swine; Temperature; Transfection

We have used immunoblotting to compare expression of type I keratins in two strains of normal human epidermal keratinocytes (v and u) and their HPV16-transformed derivatives (vp and up). The levels of keratins 14 and 17 were similar in all four cell strains, whereas keratins 18 and 19 were more abundant in vp and up than in the normal parental keratinocytes. Keratin 13 was more abundant in the transformed cells than in the parentals; in addition, expression in v was higher than in u, and expression in vp was higher than in up, suggesting strain-specific variation in expression. Keratin 16 was the only keratin to be more highly expressed in v and u than in vp and up; this is consistent with the reduced capacity of the transformants for stratification and terminal differentiation. Double-label immunofluorescence of vp and up showed that more cells expressed involucrin than keratin 16. We conclude that HPV16 transformation results in marked changes in keratin expression. The increased expression of keratin 18, a keratin that is normally expressed in simple epithelia, fits well with reports of increased keratin 18 expression in invasive squamous cell carcinomas of skin and other keratinocyte-derived tumours.

Topics: Cell Line, Transformed; Cell Transformation, Viral; Fluorescent Antibody Technique; Humans; Immunoblotting; Keratinocytes; Keratins; Papillomaviridae

Human papillomavirus (HPV) type 16 (HPV16) is associated with a large percentage of cervical malignancies, and HPV16 DNA can immortalize human keratinocytes in vitro. The transforming ability of the virus resides primarily in the open reading frames E6 and E7. Retinoids are potent modulators of growth and differentiation of keratinocytes and have been shown to reverse cervical lesions resulting from HPV infection. We compared the sensitivity of normal human foreskin keratinocytes (HKc) and four immortalized HKc lines, independently obtained by transfection of different normal HKc strains with HPV16 DNA (HKc/HPV16), to growth control by retinoic acid (RA). All the HKc/HPV16 lines were 10- to 100-fold more sensitive than normal HKc to growth inhibition by RA in both clonal and mass culture growth assays. The precursor to RA, retinol, was also found to be a more potent inhibitor of growth of HKc/HPV16 than normal HKc, while beta-carotene did not inhibit growth of either normal HKc or HKc/HPV16. In addition, HKc/HPV16 lines were more sensitive than normal HKc to modulation of keratin expression by RA and retinol. No differences were observed in the rate of uptake of [3H]RA or [3H]retinol between normal HKc and HKc/HPV16. Dot blot analysis of RNA extracted from HKc/HPV16 cultured in the absence or in the presence of 10(-7) M RA showed that the expression of the HPV16 open reading frames E6 and E7 is reduced 2- to 4-fold by RA. In addition, Northern blot analysis demonstrated that RA inhibition of E6 and E7 expression was both dose and time dependent. Overall, these results suggest that the increased sensitivity of the HKc/HPV16 lines to growth control by RA may be mediated by an inhibition of the expression of HPV16 gene products which are required for the maintenance of continuous growth.

Topics: beta Carotene; Carotenoids; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Humans; Keratinocytes; Keratins; Papillomaviridae; RNA, Viral; Tretinoin; Vitamin A

Primary cultures of normal human neonatal thyroid follicular cells were transfected with a plasmid expressing a temperature-sensitive (tsA58) mutant of SV40 large T antigen. An epithelial cell line, designated B-thy-ts.1, was obtained which showed tight temperature-dependent growth. In sharp contrast to previous such lines, which were derived from adult thyroid, B-thy-ts.1 has retained a well-differentiated phenotype as reflected in its morphology and cytokeratin expression pattern. In addition to phenotypic stability the line also displays an unusually stable karyotype, lacking the usual clastogenic effects of SV40, which we speculate to result from a greater DNA repair capacity of its cell of origin. B-thy-ts.1 should be a particularly useful tool with which to study the effects of activated oncogenes on epithelial growth and differentiation.

Topics: Antigens, Polyomavirus Transforming; Cell Adhesion; Cell Differentiation; Cell Division; Cell Transformation, Viral; Cells, Cultured; Epithelial Cells; Genetic Variation; Growth Substances; Humans; Immunohistochemistry; Infant, Newborn; Iodide Peroxidase; Karyotyping; Keratins; Mutation; Phenotype; Temperature; Thyroglobulin; Thyroid Gland; Transfection

We have recently shown that rat liver nonparenchymal epithelial cells, such as T51B cells, selectively express cytokeratin (CK) 14 as a partner of CK8 in their intermediate filaments, and we proposed CK14 as a unique cell lineage marker of the liver epithelial cell population (R. Blouin, M-J. Blouin, I. Royal, A. Grenier, A. Loranger, D. R. Roop, and N. Marceau, Differentiation, submitted for publication, 1992). In the present study, T51B-261A (spontaneously transformed) and T51B-261B (aflatoxin B1-treated) clones and clones derived from T51B cells transfected with SV40 large T (LT) and polyoma virus middle T (MT) were used to investigate CK gene expression in nontransformed and transformed liver epithelial cells. T51B-261A, T51B-261B, MT-T51B, and LT/MT-T51B clones all grew in calcium-deficient medium and formed colonies in soft agar, whereas LT-T51B clones did not grow at all in either one of these assays. T51B-261A and T51B-261B clones formed small, slow growing tumors when injected into newborn syngenic rats, whereas the MT-T51B and LT/MT-T51B clones produced rapidly forming, large tumors. There was no effect of cell transformation on CK expression, except in the clones expressing MT, where the CK intermediate filaments were completely lost. Analyses of [35S]methionine incorporation into the Triton-resistant cytoskeleton and of total proteins confirmed that CKs were absent. In contrast, vimentin intermediate filaments remained unaffected in all of the clones.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antigens, Polyomavirus Transforming; Cell Nucleus; Cell Transformation, Viral; Cytoplasm; Epithelial Cells; Fluorescent Antibody Technique; Gene Expression; Keratins; Liver; Polyomavirus; Rats; RNA, Messenger; Vimentin

We have developed, by microinjection of SV40 DNA into human milk epithelial cells, a new mammary cell line, Hu-MI, which exhibits the phenotype of luminal cells or so-called "breast cancer precursor cells." This cell line retains the phenotype of primary cells as demonstrated by the expression of keratins 18 and 19 and of polymorphic epithelial mucins. However, the cells do not grow in agar after more than 80 passages, nor do they form tumors in nude mice. Established cells contain 2 copies of SV40 DNA integrated into the cellular genome and up to 14 copies of free SV40 DNA. A deletion of the short arm of chromosome 11 (11p15) including the c-Ha-ras and the beta-globin genes was found in the immortalized cells when the DNA from these cells was compared to the DNA from peripheral blood mononuclear cells obtained from the same donor. In addition, this cell line showed a good transfection efficiency for other DNA sequences using classical transfection and selection techniques with a neomycin resistance gene (pKOneo). Selective microinjection of DNA into tumor precursor cells may prove useful for the study of the molecular mechanisms involved in breast carcinogenesis. The possible significance of the loss of 11p13-15 in malignant progression of breast cancer is discussed.

Topics: Aneuploidy; Blotting, Southern; Breast; Cell Division; Cell Membrane; Cell Transformation, Viral; Chromosomes, Human, Pair 11; DNA, Viral; Epithelial Cells; Globins; Heterozygote; Humans; Keratins; Polymorphism, Restriction Fragment Length; Proto-Oncogene Proteins; Proto-Oncogene Proteins p21(ras); Receptor, ErbB-2; Simian virus 40

When defined in terms of markers for normal cell lineages, most invasive breast cancer cells correspond to the phenotype of the common luminal epithelial cell found in the terminal ductal lobular units. Luminal epithelial cells cultured from milk, which have limited proliferative potential, have now been immortalized by introducing the gene encoding simian virus 40 large tumor (T) antigen. Infection with a recombinant retrovirus proved to be 50-100 times more efficient than calcium phosphate transfection, and of the 17 cell lines isolated, only 5 passed through a crisis period as characterized by cessation of growth. When characterized by immunohistochemical staining with monoclonal antibodies, 14 lines showed features of luminal epithelial cells and of these, 7 resembled the common luminal epithelial cell type in the profile of keratins expressed. These cells express keratins 7, 8, 18, and 19 homogeneously and do not express keratin 14 or vimentin; a polymorphic epithelial mucin produced in vivo by luminal cells is expressed heterogeneously and the pattern of fibronectin staining is punctate. Although the cell lines have a reduced requirement for added growth factors, they do not grow in agar or produce tumors in the nude mouse. When the v-Ha-ras oncogene was introduced into two of the cell lines by using a recombinant retrovirus, most of the selected clones senesced, but one entered crisis and emerged after 3 months as a tumorigenic cell line.

Topics: Animals; Antigens, Polyomavirus Transforming; Blotting, Southern; Breast; Cell Division; Cell Line; Cell Transformation, Viral; DNA, Viral; Epithelial Cells; Fluorescent Antibody Technique; Genetic Vectors; Humans; In Vitro Techniques; Keratins; Mice; Mice, Nude; Milk, Human; Oncogene Protein p21(ras); Retroviridae; Simian virus 40

To analyze the role of SV40 genome in the phenotypic alterations previously observed in SV40-transformed cell lines, we infected rabbit renal cortical cells with a temperature-sensitive SV40 mutant strain (tsA58) and compared the cell phenotypes at temperatures permissive (33 degrees C) and restrictive (39.5 degrees C) for SV40 genome expression. At both temperatures, the resulting cell line (RC.SVtsA58) expresses cytokeratin and uvomorulin, but epithelial differentiation is more elaborate at 39.5 degrees C as shown by the formation of a well-organized cuboidal monolayer with numerous tight junctions and desmosomes. Functional characteristics are also markedly influenced by the culture temperature: cells grown at 33 degrees C respond only to isoproterenol (ISO, 10(-6) M) by a sevenfold increase in cAMP cell content above basal values; in contrast, when transferred to 39.5 degrees C, they exhibit increased sensitivity to ISO (ISO/basal: 19.1) and a dramatic response to 10(-7) M dDarginine vasopressin (dDAVP/basal: 18.2, apparent Ka: 5 X 10(-9) M) which peaks 48 h after the temperature shift. The latter is associated with membrane expression of V2-type AVP receptors (approximately 50 fmol/10(6) cells) which are undetectable when SV40 genome is activated (33 degrees C). Clonal analysis, additivity studies, and desensitization experiments argue for the presence of a single cell type responsive to both AVP and ISO. The characteristics of the RC. SVtsA58 cell line at 39.5 degrees C (effector-stimulated cAMP profile, lack of expression of brush-border hydrolases and Tamm-Horsfall protein) suggest that it originates from the cortical collecting tubule, and probably from principal cells.

Topics: Animals; Arginine Vasopressin; Cadherins; Cell Division; Cell Line; Cell Transformation, Viral; Cyclic AMP; Dinoprostone; Epithelium; Gene Expression Regulation, Viral; In Vitro Techniques; Isoproterenol; Keratins; Kidney Tubules, Collecting; Membrane Fluidity; Membrane Potentials; Microscopy, Electron; Rabbits; Receptors, Angiotensin; Receptors, Vasopressin; Simian virus 40; Temperature; Virulence Factors, Bordetella

Studies on cell lines have greatly improved our understanding of many important biological questions. Generation of cell lines is facilitated by the introduction of immortalizing oncogenes into cell types of interest. One gene known to immortalize many different cell types in vitro encodes the simian virus 40 (SV40) large tumor (T) antigen (TAg). To circumvent the need for gene insertion in vitro to generate cell lines, we created transgenic mice harboring the SV40 TAg gene. Since previous studies have shown that TAg expression in transgenic mice is associated with tumorigenesis and aberrant development, we utilized a thermolabile TAg [from a SV40 strain, tsA58, temperature sensitive (ts) for transformation] to reduce the levels of functional TAg present in vivo. To direct expression to a broad range of tissues, we used the mouse major histocompatibility complex H-2Kb promoter, which is both widely active and can be further induced by interferons. tsA58 TAg mRNA was expressed in tissues of all animals harboring the hybrid construct. Development of all tissues was macroscopically normal except for thymus, which consistently showed hyperplasia. Fibroblast and cytokeratin+ thymic epithelial cultures from these mice were readily established without undergoing crisis and were conditionally immortal in their growth; the degree of conditionality was correlated with the levels of tsA58 TAg detected. One strain of H-2Kb-tsA58 mice has been bred through several generations to homozygosity and transmits a functional copy of the transgene.

Topics: Animals; Blotting, Northern; Blotting, Western; Cell Line; Cell Transformation, Viral; Cloning, Molecular; Epithelium; Fibroblasts; Fluorescent Antibody Technique; Hyperplasia; Interferon-gamma; Keratins; Mice; Mice, Transgenic; Nucleic Acid Hybridization; Promoter Regions, Genetic; RNA; Simian virus 40; Skin; Thymus Gland

The epithelia lining the vas deferens and epididymis are directly involved in the pathology of the autosomal recessive disease cystic fibrosis (CF). We have established culture systems for these epithelial cells. Long-term cell lines have now been generated from these primary epithelial cells by transformation with a plasmid containing an origin-defective simian virus 40 (SV40). Lines have been established from vas deferens and epididymis and both maintain expression of the CF gene.

Topics: Base Sequence; Cell Line, Transformed; Cell Transformation, Viral; Cystic Fibrosis; DNA; Epididymis; Epithelial Cells; Epithelium; Gene Expression Regulation; Genes, Recessive; Humans; Keratins; Male; Molecular Sequence Data; Mucins; Plasmids; Vas Deferens

Human cervical cells are a primary site of papillomavirus infection and 90% of all cervical tumors are positive for human papillomavirus (HPV) DNA. Over one-half million cases of HPV-associated cervical, vulvar, and penile cancers are reported per year. Yet, in spite of the magnitude of this problem, the effects of HPV infection on cervical cell growth and differentiation are not well characterized. To study these effects we have developed a clonal cell line of HPV-16-immortalized ectocervical epithelial cells, ECE16-1. In the present study we demonstrate that under normal growth conditions the cytokeratin content of ECE16-1 cells is dramatically altered compared to normal cervical cells; the level of K5, K6, K14, K16, and K17 is reduced and the level of K7, K8, and K19 is increased. We demonstrate that this change is largely due to a difference in the response of the cells to retinoids, as growth in retinoid-free medium produces a complete normalization of cytokeratin levels. Upon addition of natural and synthetic retinoids, the levels of cytokeratins K5, K6, K14, K16, and K17 are reduced, while the levels of cytokeratins K19, K7, and K8 are increased. Cytokeratin K13 levels are only slightly altered. The level of involucrin, a precursor of the cervical cell envelope (superficial cell), is not changed by immortalization nor is it regulated by retinoids. Transglutaminase activity is also not appreciably altered by immortalization; however, ECE16-1 cells make fewer envelopes than normal ECE cells. Our results clearly indicate that natural and synthetic retinoids suppress the differentiation of HPV transformed cervical cells. In early, low grade, cervical intraepithelial neoplasia, transcription of the HPV16 E6/E7 oncogenes is confined to the suprabasal layers. Our results suggest that retinoids, because they inhibit the differentiation of HPV16 immortalized cervical cells, may reduce the extent of viral oncogene transcription and thus be useful in slowing the neoplastic process.

Topics: Cell Differentiation; Cell Transformation, Viral; Cells, Cultured; Cervix Uteri; Epithelial Cells; Epithelium; Female; Humans; Keratins; Papillomaviridae; Phenotype; Retinoids; RNA, Messenger; Transcription, Genetic; Transfection; Tretinoin; Uterine Cervical Neoplasms; Virus Replication; Vitamin A

Human papillomaviruses (HPV) are associated with papillomatosis of the larynx, trachea, and bronchi in decreasing order of frequency, and these papillomatosis lesions may become malignant. When the patients are not selected for a history of papillomatosis, the frequency of HPV in bronchogenic carcinoma tissue is 1-5%. In order to develop a model for investigating the role of HPV in human bronchogenic carcinogenesis, normal human bronchial epithelial cells were transfected with cloned full-length HPV16 or HPV18. Two HPV18-transformed cell lines (BEP1 and BEP2) and one HPV16-transformed cell line (BEP3) were established. These nontumorigenic epithelial cell lines have: (a) attained over 100 population doublings in vitro; (b) mutually exclusive human marker chromosomes; (c) HPV DNA in forms that are consistent with chromosomal integration by Southern analysis; (d) HPV E6, E7, and E6* mRNA transcripts by Northern and reverse transcriptase-polymerase chain reaction analysis; and (e) diminished confluence-induced squamous differentiation. These cell lines should be useful for studying mechanisms involved in proliferation, differentiation, and neoplastic transformation of human bronchial epithelial cells.

Topics: Base Sequence; Blotting, Northern; Blotting, Southern; Bronchi; Cell Line; Cell Transformation, Viral; Chromosome Mapping; DNA Fingerprinting; Epithelium; Humans; Keratins; Molecular Sequence Data; Papillomaviridae; Plasmids; Polymerase Chain Reaction; Transcription, Genetic; Transfection

The thymic microenvironment contains a mixture of phenotypically distinct epithelial cells of varied functions, some of which are unknown. In an attempt to understand their relevance to T cell differentiation in the thymus, human thymic epithelial cell clones from both fetal (SM3-SM5) and postnatal (SM6) thymus were produced by using a defective recombinant retroviral vector encoding the simian virus 40 large T antigen and the neomycin resistance gene. The presence of keratins 8 and 18, desmosomes, and tonofilaments confirmed the epithelial origin of the cell strains. The cells expressed Thy-1 and HLA-Class I at high levels, showed weak-expression antigens defined by TE3B and A2B5, and low to negligible levels of the MR19-defined molecule. When compared with the phenotype of thymic epithelial cells in situ, the cell strains appear to be derived from neuroendocrine components in the outer cortical region of the human thymus. The use of retroviral vectors to transform human thymic epithelium was considerably more efficient than transfection with a plasmid carrying the origin of replication-defective SV40 large T gene. In the latter case, only two cell strains with subcapsular epithelial phenotypes were derived from fetal thymus. With the retroviral vectors, epithelial cell strains could, for the first time, be generated from human postnatal thymus as well as from fetal thymus.

Topics: Cell Division; Cell Transformation, Viral; Cells, Cultured; Clone Cells; Epithelium; Female; Genetic Vectors; Humans; Keratins; Phenotype; Pregnancy; Simian virus 40; Thymus Gland

The frequent detection of anti-neutrophilocyte-cytoplasm-antibodies (ANCA) in patients with Wegener's granulomatosis (WG) led to the supposition that this disease might be of autoimmune nature. For some authors assume that Epstein-Barr virus (EBV) infection of human B-lymphocytes besides polyclonal activation could reveal the cryptic immune status against different autoantigens in patients with autoimmune diseases we investigated EBV-transformed B-lymphocytes from patients with Sjögren's syndrome, mixed connective tissue disease, WG and healthy blood donors. Two stable B-cell lines (Ho3, We1) could be established. Inhibition experiments showed that antibodies produced by transformed B-lymphocytes and serum ANCA (C-ANCA type) of 10 WG patients recognized the identical antigen. Stimulation of one clone (Ho3) with interleukin 6 (IL-6) led to a switch from IgM to IgG production. Antibodies produced by this clone also stained glomeruli of human frozen kidney sections. Western blot analysis using immunoaffinity purified antigen prepared from human granulocytes revealed a reaction with a protein of approx. 29 kD MW. Our data underscore some new aspects concerning the direct pathogenicity of C-ANCA confirming the hypothesis that the autoimmune B-cell repertoire in WG not only reflects a polyclonal B-cell activation but is shaped by antigen driven responses.

Topics: Aged; Antibodies, Antineutrophil Cytoplasmic; Autoantibodies; B-Lymphocytes; Blotting, Western; Cell Transformation, Viral; Cross Reactions; Fluorescent Antibody Technique; Granulomatosis with Polyangiitis; Herpesvirus 4, Human; Humans; Immunoglobulin G; Immunoglobulin M; In Vitro Techniques; Interleukin-6; Keratins; Kidney Glomerulus; Middle Aged

Human papillomavirus (HPV) DNAs are detected in approximately 90% of anogenital carcinomas. To assess directly the effect of HPV on squamous differentiation, normal human cervical and foreskin epithelial cells and cells immortalized by recombinant HPV DNAs were transplanted beneath a skin-muscle flap in athymic mice. Xenografts containing normal cells formed well-differentiated stratified squamous epithelia 2 to 3 weeks after transplantation, but cell lines immortalized by four HPV types (HPV16, HPV18, HPV31, and HPV33) detected in anogenital cancer exhibited dysplastic morphology and molecular alterations in gene expression characteristic of intraepithelial neoplasia. Morphological alterations were accompanied by delayed commitment to terminal differentiation, alterations in the pattern of involucrin expression, and reductions in levels of involucrin and keratin 1 RNAs. HPV18-immortalized cells developed dysplastic changes more rapidly than cells immortalized by HPV16 DNA. These results show that human genital epithelial cells immortalized by HPV DNAs detected in genital cancers undergo dysplastic differentiation in vivo.

Topics: Animals; Cell Adhesion; Cell Differentiation; Cell Line; Cell Transformation, Viral; Cervix Uteri; Epithelium; Female; Gene Expression Regulation, Viral; Genes, Viral; Humans; Keratins; Laminin; Male; Mice; Mice, Nude; Papillomaviridae; Penis; Protein Precursors; RNA; Transfection

The association of Epstein-Barr virus (EBV) with nasopharyngeal carcinoma (NPC) has been known for some time, but the precise role of EBV in this cancer is poorly understood, due partly to the lack of an in vitro system for studying NPC cells and the effect of EBV on epithelial cells. Biopsies of NPC tumours have revealed expression of the EBV latent membrane protein (LMP) in 65% of cases, suggesting that in at least some NPC tumours LMP may contribute to cell transformation. Here we address the question of the effect of LMP expression on epithelial cells. Transfection of an immortalized, non-tumorigenic keratinocyte cell line (RHEK-1) with the LMP gene causes a striking morphological transformation: the originally flat, polygonal colonies change to bundles of spindle-shaped cells that form multilayer foci, and cytokeratin expression is down-regulated. Our results suggest that LMP expression may be an important causal factor in the development of NPC.

Topics: Antigens, Viral; Blotting, Western; Cell Transformation, Viral; Cells, Cultured; Genes, Viral; Herpesvirus 4, Human; Humans; In Vitro Techniques; Keratinocytes; Keratins; Membrane Proteins; Nasopharyngeal Neoplasms; Transfection; Viral Proteins

We undertook to extend the in vitro lifespan of epithelial cell cultures useful for the study of the cellular defect underlying cystic fibrosis (CF). Primary cultures from sweat glands of four CF and four non-CF and from nasal polyps of one non-CF and two CF individuals were transformed using a chimaeric virus, Ad5/SV40 1613 ori-. The extended lifespans ranged from 20 to more than 250 population doublings beyond that of the primary cultures. Despite some degree of aneuploidy (as assayed by total cellular DNA content) all samples tested retained at least one copy of the region of chromosome 7 containing the CF gene (as assayed by probing with flanking DNA markers). Epithelial characteristics, including an epithelioid morphology, tight junctions and desmosomes, apical microvilli, keratin networks, and dome formation were positive in the majority of cells examined, although variably expressed. All cells tested demonstrated outwardly rectifying chloride channels by patch clamp, with some from non-CF cells responsive to the catalytic subunit of cyclic AMP-dependent protein kinase. The cells were used for DNA transfection assays with selectable marker genes in appropriate vectors, in order to develop methodology for assaying the function of the CF gene product and the effects of mutations.

Topics: Cell Division; Cell Line, Transformed; Cell Survival; Cell Transformation, Viral; Cystic Fibrosis; DNA; Epithelial Cells; Humans; Keratins; Microscopy, Electron; Nasal Polyps; Sweat Glands

To study hormone responsive genes in differentiated epithelial cells and as a model for endometrial carcinoma, lines were established from primary rat endometrial cells by infection with replication-defective retroviruses carrying oncogenes and the selectable gene neo. The initial step involved immortalization through the large T antigen of SV40 to generate a line we designate RENT4, or with the E1a gene of adenovirus to generate lines referred to as RENE1 and RENE2. Additionally, lines generated by large T antigen of SV40 were superinfected with a replication-defective retrovirus harboring the v-Ha-ras oncogene and selected by the ability to form colonies in soft agar. The latter cell lines appeared fully transformed and were designated RENTR01 and RENTR03. Five established lines were characterized for steroid hormone receptors, alkaline phosphatase activity and their complement of the intermediate filaments vimentin and cytokeratin. With the exception of the RENE1 cells all other lines have normal levels of glucocorticoid receptor, whereas only RENE1, RENE2 and RENT4 were positive for the progesterone receptor. RENTR01, RENTR03 and, to a lesser extent, RENE1 exhibited differential expression of cytokeratins dependent upon whether the cells were grown on a substrata of NIH3T3 cells. When grown on formalin-fixed NIH3T3 cells, RENTR01 and RENTR03 cells appeared to differentiate or rearrange themselves in culture. Individual islands of cells showed a heterogeneous pattern of intermediate filaments with vimentin-positive cells localized to the outer portion of the islands whereas cytokeratin-positive cells are seen on the insides of these structures.

Topics: Alkaline Phosphatase; Animals; Biomarkers, Tumor; Cell Line; Cell Transformation, Viral; Endometrium; Female; Immunohistochemistry; Keratins; Oncogene Proteins, Viral; Phenotype; Rats; Receptors, Estrogen; Receptors, Glucocorticoid; Receptors, Progesterone; Retroviridae; Retroviridae Proteins, Oncogenic; Vimentin

Immortalized, but nontumorigenic, human keratinocyte cell lines have many potential therapeutic and experimental uses. We have utilized a recombinant retrovirus, encoding the simian virus 40 large T-antigen, to immortalize normal human epidermal keratinocytes. The KER-1 cells derived from the immortalization process grow without feeder layer support, but do not form colonies in soft agar. Morphologically, the KER-1 cells appear similar to nonimmortalized cells, except that stratification is somewhat reduced. The pattern of keratin gene expression in nonimmortalized and KER-1 cells is similar, except for the retinoid-dependent regulation of type I cytokeratin, K7, in the KER-1 cells. This keratin is not expressed in nonimmortalized keratinocytes, but is present at low levels in KER-1 cells. Incubation with trans-retinoic acid (20 or 200 nM) or retinol (200 or 2000 nM) results in a 40-fold increase in K7 expression in KER-1 cells. The cornified envelope precursor, involucrin, is expressed at normal levels in KER-1 cells. Moreover, as in nonimmortalized cells, KER-1 involucrin levels are not suppressed by retinoids. trans-Retinoic acid and retinol reduce envelope formation in both nonimmortalized keratinocytes and KER-1 cells. Surprisingly, the synthetic retinoid, Ro 13-6298 (p [(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthyl)-propenyl]benzoic acid ethyl ester), a potent regulator of keratin gene expression, cornified envelope formation and morphological change in nonimmortalized cells, is completely inactive in KER-1 cells.

Topics: Antigens, Polyomavirus Transforming; Cell Transformation, Viral; Gene Expression Regulation; Humans; Keratinocytes; Keratins; Molecular Weight; Protein Precursors; Retinoids

Normal human foreskin keratinocytes cotransfected with the neomycin resistance gene and recombinant human papillomavirus (HPV) DNAs (types 16, 18, 31, and 33) that have a high or moderate association with cervical malignancy acquired immortality and contained integrated and transcriptionally active viral genomes. Only transcripts from the intact E6 and E7 genes were detected in at least one cell line, suggesting that one or both of these genes are responsible for immortalization. Recombinant HPV DNAs with low or no oncogenic potential for cervical cancer (HPV1a, -5, -6b, and -11) induced small G418-resistant colonies that senesced as did the nontransfected cells. These colonies contained only episomal virus DNA; therefore, integration of HPV sequences is important for immortalization of keratinocytes. This study suggests that the virus-encoded immortalization function contributes to the pathogenesis of cervical carcinoma.

Topics: Carcinoma; Cell Transformation, Viral; Cells, Cultured; DNA, Viral; Electrophoresis, Agar Gel; Epidermal Cells; Epidermis; Female; Humans; Keratins; Papillomaviridae; Plasmids; RNA, Messenger; RNA, Viral; Transfection; Uterine Cervical Neoplasms

A human epidermal cell culture was transformed by transfection with a recombinant plasmid containing simian virus 40 DNA with a deletion at the origin and an antibiotic (neomycin or G418) marker. A calcium phosphate-mediated DNA transfection method was optimized for introducing exogenous DNA into cells maintained in a fully defined medium. The transformed cells were propagated for more than 200 population doublings and did not appear to go through a "crisis" period. The growth characteristics of the transformed cells were similar to those of untransformed cells. Major keratins synthesized in the transformed cells were similar to those found in normal epidermal cells. Transformed cells initially transfected with the recombinant plasmid could be propagated for more than 30 passages. Actively growing cells could then be repeatedly selected from cell populations based upon their neomycin (G418)-resistant phenotype for at least another 30 passages. Simian virus 40 T-antigen and extrachromosomal DNA containing plasmid- and SV40-specific DNA sequences were detected in the transformed cells. Because of their nononcogenic phenotype and defined growth requirements, the transformed cells provide a model for examining structural changes during cell proliferation and differentiation, and for exploring the multistage carcinogenesis of human epithelial cells.

Topics: Antigens, Polyomavirus Transforming; Calcium; Cell Differentiation; Cell Line, Transformed; Cell Transformation, Viral; Culture Media; DNA, Viral; Epidermal Cells; Humans; Keratins; Neomycin; Plasmids; Simian virus 40; Transfection

To investigate the antineoplastic activity of parvoviruses, proliferating normal human epidermal cells and a series of established keratinocyte cell lines derived from squamous cell carcinomas or transformed in vitro, were compared for the outcome of H-1 virus infection. All established keratinocyte cell lines were more sensitive to killing by H-1 virus than normal epidermal cells, although to varying extents. Using a step-wise procedure for malignant transformation in vitro, we found that sensitization of transformed epidermal cells to H-1 virus can be dissociated from the acquisition of a tumorigenic phenotype. Thus, spontaneously- or SV40-immortalized human keratinocytes were moderately and highly sensitive to H-1 virus, respectively, and could be made tumorigenic by Harvey-ras oncogene transfection without a major change in their susceptibility to the virus. The capacity of human keratinocytes for replicating and expressing H-1 virus DNA appears to be a revealer of cellular alterations that take place in at least some pathways to malignant transformation but that may be insufficient to confer a tumorigenic potential.

Topics: Cell Survival; Cell Transformation, Neoplastic; Cell Transformation, Viral; Cytopathogenic Effect, Viral; DNA, Viral; Epidermis; Humans; Keratins; Parvoviridae; Tumor Cells, Cultured; Virus Replication

Differential screening of a cDNA library was used to isolate probes for mRNAs that are induced in simian virus 40 (SV40)-transformed human keratinocytes. Several of these cDNAs hybrid select mRNAs which encode transformation-induced proteins found in the cytoskeletal component of SV40-transformed keratinocytes. One of these cDNAs was used to study the phenotype of normal and transformed cell lines derived from various tissues. We found that mRNA encoding the novel transformation-induced proteins is expressed in two squamous carcinoma cell lines derived from the oral epithelium, four SV40-transformed keratinocyte cell lines, and two SV40-transformed fibroblasts. Normal or transformed lymphoid cells or cell lines derived from carcinoma of the cervix do not express mRNAs which hybridize to these probes. The results from this study suggest that these probes may be used to detect markers of transformation in certain cell types.

Topics: Base Sequence; Cell Transformation, Viral; Cells, Cultured; Cloning, Molecular; DNA; DNA, Viral; Epidermis; Humans; Keratins; Molecular Sequence Data; Poly A; Protein Biosynthesis; RNA; RNA, Messenger; Simian virus 40

By co-culturing regional lymph node B-cells and HAT-sensitive mutant cells obtained from RPMI-1788 cells, no less than 20,000 Epstein-Barr (EB)-transformed colonies were obtained from 32 patients with gastric cancer. From B-cell cultures generating antibodies reactive with gastric cancer tissues as well as cultured gastric cancer cells, two EB-transformed cell clones termed C418-59 and C1218-39 were isolated. Both of them produced human IgM-class antibodies, termed Mab418-59 and Mab1218-39, respectively. Both antibodies reacted with an antigen with a molecular weight of 45 kd existing in gastric cancer MKN-45, MKN-1, and Kato-III cells, and also with all of 4 adenocarcinomas of the stomach in paraffin sections. The antigen recognized by both antibodies was identified as a kind of cytoskeletal protein, cytokeratin 18. In this study, it was confirmed that B-cell clones generating autoantibodies against cytokeratin 18 were present in some patients with gastric cancer.

Topics: Adenocarcinoma; Antibodies, Monoclonal; Antigens; Antigens, Neoplasm; Autoantibodies; B-Lymphocytes; Blotting, Western; Cell Transformation, Viral; Electrophoresis, Polyacrylamide Gel; Herpesvirus 4, Human; Humans; Immunoenzyme Techniques; Immunoglobulin M; Keratins; Lymph Nodes; Molecular Weight; Stomach Neoplasms; Tumor Cells, Cultured

Human diploid keratinocytes may be divided into three clonal types with differing capacities for proliferation. The paraclone, which has the shortest life span, is limited to 15 divisions, after which all the cells undergo programmed terminal differentiation. By means of a retroviral vector, paraclones which have not completed their life span and which consist of not more than a few hundred cells can be transduced at a high frequency with DNA complementary to the 12S transcript of the adenovirus early region 1A gene. Transformation can be detected within a single cultivation by the formation of progressively growing colonies. The transformants appear to have an unlimited growth potential, and they form a disorganized epidermis when they are grafted as an epithelium onto athymic mice. These experiments clearly show that, in order to be transformed by a viral oncogene, the target cell need not be a stem cell.

Topics: Aged; Animals; Cell Division; Cell Transformation, Viral; Cells, Cultured; Clone Cells; Epidermal Cells; Epidermis; Female; Humans; Immunoblotting; Keratins; Mice; Mice, Nude; Oncogenes; Retroviridae; Transplantation, Heterologous

The early human papillomavirus type 16 genes that directly participate in the in vitro transformation of primary human keratinocytes have been defined. In the context of the full viral genome, mutations in either the E6 or E7 open reading frame completely abrogated transformation of these cells. Mutations in the E1, E2, and E2-E4 open reading frames, on the other hand, had no effect. Thus, both the full-length E6 and E7 genes were required for the induction of keratinocyte immortalization and resistance to terminal differentiation. The E6 and E7 genes expressed together from the human beta-actin promoter were sufficient for this transformation; mutation of either gene in the context of this recombinant plasmid eliminated the ability to induce stable differentiation-resistant transformants.

Topics: Cell Transformation, Viral; Genes, Viral; Humans; Keratins; Oncogene Proteins, Viral; Papillomaviridae; Skin; Transfection

Intermediate filaments (IFs) of the cytokeratin (CK) type are cytoskeletal elements typical for epithelial differentiation. However, in diverse transformed culture lines of non-epithelial origin, rare cells emerge spontaneously, which synthesize, in addition to their vimentin IFs, CKs 8 and 18. We enriched such cells by cloning and studied the level(s) of regulation at which these changes occur. We found that in SV40-transformed fibroblasts the CK 18 gene is constitutively transcribed into translatable mRNA but that the protein is rapidly degraded in the absence of its complex partner, CK 8. In contrast, cells immunocytochemically positive for CK IFs contained both CKs 8 and 18, which apparently stabilized in heterotypic complexes. These findings and related observations of active genes for CKs 8 and/or 18 in several other transformed non-epithelial cell lines indicate that the genes for CKs 18 and, less frequently, 8 can be active in diverse different non-epithelial cell lines; synthesis of type I and type II CK pair partners can be uncoupled; control of CK IF formation can take place at different levels. We suggest that the intrinsic instability of the inactive state of these genes is responsible for the occurrence of CKs 8 and 18 in certain non-epithelial tissues and tumors, a caveat in tumor diagnosis.

Topics: Animals; Blotting, Northern; Cell Line, Transformed; Cell Transformation, Viral; Clone Cells; Cricetinae; Fibroblasts; Gene Expression Regulation; Genes; Humans; Keratins; Mice; Protein Biosynthesis; Rats; Rhabdomyosarcoma; RNA, Messenger; Simian virus 40; Transcription, Genetic; Tumor Cells, Cultured

Simian Virus 40 (SV40) transformation of primary cultures of human mammary epithelial cells has yielded a cloned epithelial-like cell line and a representative, single-cell subclone. Although apparently homogeneous, both cloned cell lines can also yield small numbers of three other cell types. The more-elongated cell type can be obtained directly by replating cells from the medium of the epithelial-like cell cultures or by picking and culturing single cells to form representative lines. Immunofluorescent and immunocytochemical analysis of these cell lines growing on plastic or as tumor-nodules in nude mice for epithelial membrane antigens, various cytokeratins, various actins, laminin, Type IV collagen, the common acute lymphoblastic leukemia antigen (CALLA), and a 135-kDa glycoprotein confirm the epithelial nature of the epithelial-like cells and suggest a myoepithelial origin for the more-elongated cell type. Ultrastructural analysis largely confirms the results, although the myofilamental bundles can be scanty in the growing myoepithelial-like cells. The other two cell types are possibly related to the keratinizing and casein-secreting cells seen in the epithelial tumor-nodules before and after mating the mice, respectively. The myoepithelial-like cells produce 5- to 17-fold more laminin, Type IV collagen, CALLA, and the 135-kDa glycoprotein than the epithelial cells, and all of these antigens are preferentially found on myoepithelial cells in vivo. It is suggested that the SV40-transformed epithelial cell is an immortalized form of human mammary stem cell which can differentiate in culture and in vivo to myoepithelial-like cells.

Topics: Actins; Animals; Antibodies, Monoclonal; Antigens, Differentiation; Antigens, Neoplasm; Antigens, Surface; Breast; Cell Differentiation; Cell Line, Transformed; Cell Transformation, Neoplastic; Cell Transformation, Viral; Collagen; Epithelial Cells; Epithelium; Fluorescent Antibody Technique; Humans; Immunohistochemistry; Keratins; Laminin; Membrane Glycoproteins; Mice; Mice, Nude; Mucin-1; Neoplasm Transplantation; Neoplasms, Experimental; Neprilysin; Simian virus 40; Stem Cells

The oncogenic potential of human papillomavirus type 18 which is found in a significant number of cervical and penile cancer biopsies was tested in primary human keratinocytes derived from neonatal foreskin. Viral DNA and a gene for resistance to neomycin were introduced into these cells by calcium phosphate transfection. Selection of cells in G418 led to the isolation of resistant colonies which were propagated in culture. Four cell lines termed FE-A, FEH 18L, FEP18-5, and FEP18-11 have been maintained in culture for 1 1/2-2 years and were selected for further analysis. In all cases the viral DNA was integrated into the cellular genome and the early genes were transcribed, including RNA complementary to the E2, E6, and E7 open reading frames. Radioimmunoprecipitation showed that all cell lines synthesized the E6 and E7 proteins. However, none of the cell lines tested were tumorigenic. The differentiation capacity of these cells was analyzed by assessing their ability to proliferate clonally after exposure to 1.2 mM calcium chloride. All four cell lines were resistant to this stimulus and formed colonies upon return to regular growth medium whereas normal cells differentiated terminally. K6a and K14 keratin RNA expression was down-regulated in the HPV immortalized cell lines compared to primary human epithelial cells.

Topics: Blotting, Northern; Blotting, Southern; Cell Line; Cell Line, Transformed; Cell Transformation, Neoplastic; Cell Transformation, Viral; DNA, Viral; Humans; Keratinocytes; Keratins; Papillomaviridae; Radioimmunoprecipitation Assay; RNA, Viral; Transcription, Genetic; Transfection; Viral Proteins

SSA/Ro antigen is a soluble cellular component to which antibodies are frequently produced in patients with Sjögren's syndrome and systemic lupus erythematosus. Its exact location within the cell has yet to be determined. In this study we report the expression of SSA/Ro antigen in simian virus 40 (SV40)-transformed keratinocytes. The locations of SSA/Ro, U1RNP, and DNA antigens were studied by indirect immunofluorescence using monospecific antibodies. SSA/Ro antigen was detected in both the nucleus and cytoplasm of SV40-transformed keratinocytes tested with three monospecific sera. Primary cultured keratinocytes derived from adult human skin showed localized immunofluorescent staining within the nucleus. When Ca++ concentration of the medium was switched to 0.05 mM, these cells expressed cytoplasmic SSA/Ro antigens within 48 h. Depletion of the antibody activity with insolubilized human spleen extract abolished the staining. Surface expression of this antigen could not be detected in either primary or transformed cells. Localization of U1RNP and DNA was not altered. These results indicate that expression of SSA/Ro antigen in human keratinocytes is modulated by SV40 infection and that this antigen is expressed to a greater degree in cells that are less differentiated, transformed, or proliferating.

Topics: Autoantigens; Cell Transformation, Viral; Epidermis; Humans; Keratins; Ribonucleoproteins; RNA, Small Cytoplasmic; Simian virus 40

Normal human bronchial epithelial cells were infected with SV40 virus or an adenovirus 12-SV40 hybrid virus, or transfected via strontium phosphate coprecipitation with plasmids containing the SV40 early region genes. Colonies of morphologically altered cells were isolated and cultured; these cells had extended culture lifespans compared to normal human bronchial epithelial cells. All cultures eventually underwent senescence, with the exception of one which appears to have unlimited proliferative potential. Colonies arising after viral infection were screened for virus production by cocultivation with Vero cells; only viral nonproducer cultures were analyzed further. The cells retained electron microscopic features of epithelial cells, and keratin and SV40 T-antigen were detected by indirect immunofluorescence. All of the cultures were aneuploid with karyotypic abnormalities characteristic of SV40-transformed cells. No tumors formed after s.c. injection of the cells in nude mice. These cells should be useful for studies of multistage bronchial epithelial carcinogenesis.

Topics: Adenoviruses, Human; Antigens, Viral, Tumor; Bronchi; Cell Division; Cell Transformation, Viral; DNA, Viral; Epithelial Cells; Genes, Viral; Humans; Karyotyping; Keratins; Phosphates; Simian virus 40; Strontium; Transfection; Virus Replication

In this study we have examined possible differentiation-dependent modulations in plasma membrane lipid properties in normal keratinocytes, SV-40 transformed keratinocytes (SVK14) and a number of squamous carcinoma (SCC) cells. In normal keratinocytes the lateral diffusion coefficient of plasma membrane lipids (D) differs significantly for cells cultured permanently under low and normal Ca2+-conditions (5.16 x 10(-9) and 3.27 x 10(-9) cm2/s, respectively). When differentiation is induced by exposing low Ca2+-cultured cells to normal Ca2+ concentrations D increases to 7.07 x 10(-9) cm2/s during the initial hours of differentiation followed by a gradual sustained decrease to values also observed in cells cultured permanently under normal Ca2+-conditions. In SCC and SVK14 cells a similar initial transient increase in lateral lipid mobility is observed upon initiation of differentiation, but, in contrast to normal keratinocytes, no sustained decrease in D is seen upon prolonged culturing under normal Ca2+ conditions. The results indicate that the deficiency of the transformed cells to respond to Ca2+-induced differentiation might involve transformation-dependent alterations in membrane structure and function.

Topics: Calcium; Carcinoma, Squamous Cell; Cell Differentiation; Cell Membrane; Cell Transformation, Neoplastic; Cell Transformation, Viral; Cells, Cultured; Culture Media; Epidermal Cells; Epidermis; Humans; Keratins; Lipid Bilayers; Membrane Lipids

Primary human epithelial cells were cotransfected with pHPV-18 and pSV2neo, and cell strains were generated by selecting in G418. One cell strain (FE-A), which exhibits an extended life span, is currently in its 30th passage. In comparison, control cultures can only be maintained up to the seventh passage. Southern blot analysis revealed the presence of at least one intact, integrated viral genome in these cells. FE-A cells showed altered growth properties, characterized by a change in morphology, and clonal density. Differentiation markers analyzed by Western blotting (immunoblotting), such as cytokeratins and involucrin, indicated that the cells resembled a partially differentiated epithelial population. Increased expression of the 40-kilodalton cytokeratin was observed in FE-A cells, similar to that observed in simian virus 40-immortalized human keratinocytes (M. Steinberg and V. Defendi, J. Cell Physiol. 123:117-125, 1985). FE-A cells were also found to be defective in their response to terminal differentiation stimuli. Calcium and 12-O-tetradecanoyl-phorbol-13-acetate treatment induced normal epithelial cells to differentiate, whereas the human papillomavirus 18 (HPV-18)-containing keratinocytes were resistant to these signals, indicating their partially transformed nature. These cells were not able to induce tumors in nude mice over a period of up to 8 months. A second cell strain, FE-H18L, also generated by transfecting HPV-18, also exhibited an extended life span and similar alterations in morphology. Viral RNA transcribed from the early region of HPV-18 was detected in both cell strains by Northern (RNA) blot analysis. These cell strains should provide a useful model for determining the role of HPV in carcinogenesis.

Topics: Animals; Calcium; Cell Differentiation; Cell Division; Cell Transformation, Viral; Cells, Cultured; DNA, Viral; Epithelial Cells; Epithelium; Gene Expression Regulation; Immunologic Techniques; Keratins; Male; Mice; Mice, Nude; Neoplasms, Experimental; Papillomaviridae; Protein Precursors; RNA, Messenger; RNA, Viral

An in vitro system for studying the interaction between human papillomavirus (HPV) 16 and 18 recombinant DNA and normal human exocervical epithelial cells is described. Eight HPV-immortalized human exocervical epithelial cell lines were established; all the lines contained either integrated HPV16 or 18 sequences and expressed HPV mRNAs. Thus, integration and expression appear to be required for immortalization. Immortalized cells (greater than 200 population doublings to date) divided rapidly (doubling time of 30 to 46 h) and morphologically resembled primary cultures of normal human exocervical epithelial cells. They expressed a keratin pattern consistent with their origin from exocervical epithelium. When cultured at high density or in the presence of serum they terminally differentiated. Sublines resistant to terminal differentiation were selected by growth in serum-supplemented medium. Keratin pattern changes suggest they have some properties in common with cervical squamous carcinoma cells. However, HPV-immortalized cell lines were not tumorgenic in nude mice. Thus, HPV16/18 is not carcinogenic by itself. These cell lines represent an appropriate model for studying factors that regulate HPV gene expression in normal cervical epithelial cells and examining the influence of cocarcinogens on neoplastic progression.

Topics: Animals; Cell Line; Cell Transformation, Viral; Cervix Uteri; DNA, Viral; Epithelium; Female; Humans; Keratins; Mice; Papillomaviridae; RNA, Messenger; Transfection; Uterine Cervical Neoplasms

Immortalization of human keratinocytes (HKc) by human papillomavirus type 16 (HPV16) is reproducible at a high frequency, is due directly to the presence of the viral sequences in the cells, and occurs independently from the genetic characteristics of the host cells. Ten human keratinocyte strains, each derived from a different individual, were transfected with pMHPV16d and selected with G418. Eight became established lines. Two strains, which failed to grow shortly after successful G418 selection, were negative for HPV16 DNA. No lines were established following transfection of the same HKc strains with vector sequences only. The immortalized lines maintained a constant number of copies of the viral genome integrated into the cellular DNA. Each line showed a unique integration pattern of HPV16 sequences into the cellular genome, but expressed similar patterns of viral messages. Sublines able to grow in the absence of growth factors (epidermal growth factor and bovine pituitary extract), and others which became resistant to differentiation stimuli (serum and calcium) were obtained by selection in growth factor-free medium and serum-supplemented medium, respectively. The establishment of continuous cell lines is a direct consequence of the presence of viral sequences; however, because none of these lines formed tumors in nude mice, additional events must be necessary for progression of malignancy. HPV16-immortalized human keratinocyte lines can be used to investigate and identify the viral factors involved with the modification of growth and differentiation control by HPV16.

Topics: Aneuploidy; Cell Cycle; Cell Differentiation; Cell Line; Cell Transformation, Viral; DNA, Viral; Epidermal Cells; Epidermis; Gene Expression Regulation; Genes, Viral; Growth Substances; Humans; Keratins; Papillomaviridae; RNA, Viral

To facilitate understanding of the mechanisms underlying pulmonary diseases, including lung cancer and cystic fibrosis, we have transformed and characterized cultures of human tracheal epithelial cells. Cells were transfected by calcium phosphate precipitation with a plasmid containing a replication-defective simian virus 40 (SV40) genome. Colonies of cells with enhanced growth potential were isolated and analyzed for transformation- and epithelial-specific characteristics. Precrisis cells were observed to express the SV40 large tumor antigen, produce cytokeratins, have microvilli, and form tight junctions. After crisis, cells continued to express the SV40 large tumor antigen as well as epithelial-specific cytokeratins and to display the apical membrane microvilli. Apical membrane Cl channels were opened in postcrisis cells exposed to 50 microM forskolin. These channels showed electrical properties similar to those observed in primary cultures. The postcrisis cells have been in culture for greater than 250 generations and are potentially "immortal." In addition to providing a useful in vitro model for the study of ion transport by human airway epithelial cells, the cells can be used to examine stages of neoplastic progression.

Topics: Cell Line, Transformed; Cell Transformation, Neoplastic; Cell Transformation, Viral; Chlorides; Defective Viruses; Epithelium; Humans; Ion Channels; Keratins; Oncogenes; Simian virus 40; Trachea

The association of certain human papillomavirus (HPV) types with the majority of human cervical carcinomas suggests a role for the virus in the development of this type of cancer. In this paper, we have examined the transforming properties of several HPV types where the early region genes of the virus are under the control of a strong heterologous promoter and show that major differences exist between the HPV types in their ability to transform primary rat kidney epithelial cells in conjunction with an activated ras oncogene. Those HPV types most commonly found in carcinomas--types 16, 18, 31 and 33--are capable of co-operating with ras to transform primary cells, but those types most commonly found in benign lesions--types 6 and 11--are not. We further demonstrate that the E7 gene of HPV16 by itself is sufficient to co-operate with activated ras to produce transformed cells which are tumorigenic in immunocompetent animals.

Topics: Adenocarcinoma; Animals; Cell Transformation, Viral; Cells, Cultured; DNA, Recombinant; DNA, Viral; Epithelium; Genes, Viral; Keratins; Kidney; Neoplasm Proteins; Oncogene Proteins, Viral; Oncogenes; Papillomaviridae; Rats

Keratinocytes electroporated with human papillomavirus (HPV) DNA (HPV-6, 11, 16 and 18) exhibited an increased cellular proliferation which was quantitated as microcolony and macrocolony formation. However, only macrocolonies induced by HPV-16 or HPV-18 DNA (the two viral types most commonly found in human cervical carcinomas) gave rise to proliferating, poorly-stratified colonies when grown in the presence of serum and calcium. Hydrocortisone increased the frequency of these differentiation-resistant colonies, and studies showed that they were immortalized, contained one copy of viral DNA per cell, expressed three discrete species of viral RNA and synthesized the viral E7 protein. HPV-induced cellular proliferation and altered differentiation are therefore separable events and may represent the activity of different viral genes.

Topics: Biological Assay; Blotting, Southern; Calcium; Cell Differentiation; Cell Division; Cell Transformation, Viral; DNA, Viral; Epidermal Cells; Female; Humans; In Vitro Techniques; Keratins; Male; Papillomaviridae; Uterine Cervical Neoplasms; Viral Proteins

SV-40 transformed human foreskin keratinocytes (line SV-K14) develop under conditions of serum starvation the competence to form cornified envelopes that are characteristic of terminally differentiating epidermal cells. In this cell line, the final assembly of the envelope does not occur spontaneously but must be induced using a calcium ionophore. Five potential precursor proteins with molecular weights of 140K, 90K, 61K, 53K, and 36K, respectively, could be detected in the extracts of envelope competent and noncompetent cells. The 61 kD and the 36 kD precursors were specifically decorated in immunoblots when using an antiserum directed against the purified cornified envelope of SV-K14 cells. The 140 kD protein was identified as involucrin by means of a commercial anti-involucrin antibody. Part of the 61 kD protein was found to be inserted into the plasma membrane after the cells gained envelope competence. The set of precursor proteins used by SV-K14 cells differed markedly from those described in the literature for epidermal cells in vivo and for normal human keratinocytes in vitro. Furthermore, cyanogen bromide cleavage of purified envelopes from transformed and normal keratinocytes revealed a completely different peptide pattern. This indicates that the exact molecular composition of the cornified envelope may not be strictly determined and may vary according to the availability of potential substrate proteins at the very moment when the cross-linking enzyme, the plasma membrane associated transglutaminase, becomes functional.

Topics: Cell Line; Cell Transformation, Viral; Electrophoresis; Humans; Keratins; Male; Protein Precursors; Simian virus 40; Skin; Subcellular Fractions; Tissue Distribution; Viral Envelope Proteins

Herpes simplex virus type 1 (HSV-1) infection of human fibroblast cells grown in culture induces reorganization of the cytoskeleton fibrillar structures. Normal transport and insertion of HSV glycoproteins into the plasma membrane of the cells depend on the integrity of the microtubules. The natural host cells for HSV are epithelial cells, and an epithelial cell line established from rat palate was used in the present study. The effect of virus on the structure of the intermediate filaments and especially on the keratin proteins was studied. Two-dimensional gel electrophoresis of total cell extracts identified in uninfected cells two major acidic keratin proteins with apparent molecular weights of 44,000 (44K) and 48K (pI 5.45 to 5.30, 5.50 to 5.35). A new keratin protein of 46K (pI 5.40 to 5.25) appeared in infected cells between 8 h and 12 h post-infection. Pulse-chase experiments identified the 46K protein as a processed form of the 48K keratin component, which was also cleaved in uninfected cells grown in the presence of cycloheximide. Partial proteolysis of the 46K and 48K keratins with Staphylococcus aureus V8 protease showed that the 48K and the 46K proteins differed in only one oligopeptide. The significance of the changed keratin composition of HSV-infected cells is discussed.

Topics: Animals; Cell Line; Cell Transformation, Viral; Cycloheximide; Cytoskeleton; Epithelium; Intermediate Filaments; Keratins; Molecular Weight; Palate; Rats; Simplexvirus

Viruses have been postulated to be involved in the induction of autoantibodies by: autoimmunization with tissue proteins released by virally induced tissue damage; immunization with virally encoded antigens bearing molecular similarities to normal tissue proteins; or nonspecific (polyclonal) B cell stimulation by the infection. Infectious mononucleosis (IM) is an experiment of nature that provides the opportunity for examining these possibilities. We show here that IgM antibodies produced in this disease react with at least nine normal tissue proteins, in addition to the virally encoded Epstein-Barr nuclear antigen (EBNA-1). The antibodies are generated to configurations in the glycine-alanine repeat region of EBNA-1 and are crossreactive with the normal tissue proteins through similar configurations, as demonstrated by the effectiveness of a synthetic glycine-alanine peptide in inhibiting the reactions. The antibodies are absent in preillness sera and gradually disappear over a period of months after illness, being replaced by IgG anti-EBNA-1 antibodies that do not crossreact with the normal tissue proteins but that are still inhibited by the glycine-alanine peptide. These findings are most easily explained by either a molecular mimicry model of IgM autoantibody production or by the polyclonal activation of a germline gene for a crossreactive antibody. It also indicates a selection of highly specific, non-crossreactive anti-EBNA-1 antibodies during IgM to IgG isotype switching.

Topics: Alanine; Amino Acid Sequence; Antibody Specificity; Antigens, Viral; Autoantibodies; B-Lymphocytes; Cell Transformation, Viral; Epstein-Barr Virus Nuclear Antigens; Glycine; Herpesvirus 4, Human; Humans; Immunoglobulin M; Infectious Mononucleosis; Keratins; Repetitive Sequences, Nucleic Acid

Normal keratinocytes, SV40-transformed keratinocytes (SVK14), and various squamous carcinoma cell (SCC) lines have been used as an in vitro model system to study the properties of phorbol ester receptor and protein kinase C expression during keratinocyte differentiation. The cell lines used exhibit a decreasing capacity to differentiate in the order of keratinocytes approximately SVK14 greater than SCC-12F2 greater than SCC-15 greater than SCC-4; moreover, all cell lines respond to a low external Ca2+ concentration by a decreased capacity to differentiate. Normal keratinocytes exhibited the highest number of phorbol ester receptors as compared to the other cell lines, while each individual cell line exhibited a higher number of phorbol ester receptors during growth under normal Ca2+ conditions as compared to cells grown under low Ca2+ conditions. The apparent dissociation constant (Kd) demonstrated only small variations in the various cell lines. In contrast, the cytoplasmic protein kinase C activity, was found to be higher in cells grown under low Ca2+ conditions than in cells grown under normal Ca2+ conditions, indicating the absence of a causal relationship between cytoplasmic protein kinase C activity and phorbol ester receptor expression. Therefore the properties of protein kinase C have been determined in more detail in normal keratinocytes and SCC-15 cells. These studies revealed differences between protein kinase C properties from the two cell lines grown under normal and low Ca2+ conditions. The differences included the effect of phorbol 12-myristate 13-acetate (PMA) on the redistribution pattern of protein kinase C between the cytoplasmic and particulate fractions as well as the activating effect of diolein in vitro on protein kinase C activity, partly purified from particulate or cytoplasmic fractions. These observations demonstrate that the functional protein kinase C activity of keratinocytes is determined by various endogenous and exogenous activators and that these activators are modulated differently in various cell lines, under various growth conditions (low Ca2+ versus normal Ca2+).

Topics: Caenorhabditis elegans Proteins; Carcinogens; Carrier Proteins; Cell Line; Cell Transformation, Viral; Cells, Cultured; Epidermal Cells; Epidermis; ErbB Receptors; Humans; Keratins; Phorbol 12,13-Dibutyrate; Phorbol Esters; Protein Kinase C; Receptors, Drug; Simian virus 40; Tetradecanoylphorbol Acetate

Human foetal keratinocytes were transfected with a recombinant plasmid (pSV6-1) which contained an origin defective SV40 genome. The resulting transformed cell line had many properties in common with previously described SV40-transformed keratinocytes, including expression of simple epithelial-type keratins. It was non-tumourigenic in nude mice at early passages, forming small benign cysts, however, after approximately 46 in vitro passages, these transformed keratinocytes formed invasive squamous cell carcinomas in athymic nude mice. Several in vitro changes were associated with this acquisition of tumourigenicity (a) an alteration in cellular morphology, (b) development of a cytogenetically marked clone and (c) loss of cell surface fibronectin. The loss of fibronectin was also observed in vivo; cysts formed by SV6-1 Bam/HFK produced human fibronectin whereas tumours did not, although both tumours and cysts were laminin- and keratin-positive. These results indicate that the spontaneous development of secondary events in immortalised human cells may lead to the acquisition of a malignant phenotype.

Topics: Animals; Carcinoma, Squamous Cell; Cell Line, Transformed; Cell Transformation, Neoplastic; Cell Transformation, Viral; Epidermis; Fibronectins; Fluorescent Antibody Technique; Humans; Karyotyping; Keratins; Male; Mice; Mice, Nude; Neoplasm Transplantation; Simian virus 40; Skin Neoplasms; Transfection

The heat production of normal and transformed human epidermal keratinocytes precultured in Petriperm tissue culture dishes was measured calorimetrically. For this purpose, the membrane at the bottom of the culture dish was cut out aseptically and put into a microcalorimeter vessel with the cell layer inwards. A continuous heat output of (83 +/- 12) pW/cell was measured for normal keratinocytes from a confluent primary culture. A value of (134 +/- 35) pW/cell was obtained when the transformed keratinocyte line SV-K14 was used. The method described in this paper is simple, leads to reproducible results, and can be easily adapted to the calorimetric study of other mammalian cells in vitro.

Topics: Calorimetry; Cell Transformation, Viral; Cells, Cultured; Epidermis; Hot Temperature; Humans; Keratins; Mitosis; Simian virus 40

Characterisation and quantitation of epidermal growth factor receptors (EGFR) have been carried out on eight human squamous carcinoma cell lines and the results compared with those from simian virus transformed keratinocytes and normal keratinocytes grown under similar conditions. All cells tested possess both high and low affinity receptors with dissociation constants ranging from 2.4 X 10(-10) M to 5.4 X 10(-9) M. When epidermal growth factor (EGF) binds to its receptor it is internalised and degraded and the receptor is down regulated. Malignant cells and virally transformed cells possess 5-50 times more EGF receptors than normal keratinocytes and one cell line LICR-LON-HN-5 possesses up to 1.4 X 10(7) receptors per cell, which is the highest number yet reported for a cell line. These results are discussed in the context of recent data that suggest that the increased expression of EGF receptors in epidermoid malignancies may be an important component of the malignant phenotype in these tumours.

Topics: Carcinoma, Squamous Cell; Cell Line; Cell Transformation, Viral; Chloroquine; Chromatography, High Pressure Liquid; Epidermal Cells; Epidermal Growth Factor; ErbB Receptors; Humans; Keratins; Receptors, Cell Surface; Time Factors

Efforts to investigate the progression of events that lead human cells of epithelial origin to become neoplastic in response to carcinogenic agents have been aided by the development of tissue culture systems for propagation of epithelial cells. In the present study, nontumorigenic human epidermal keratinocytes immortalized by adenovirus 12 and simian virus 40 (Ad 12-SV40) were transformed by treatment with the chemical carcinogens N-methyl-N'-nitro-N-nitrosoguanidine or 4-nitroquinoline-1-oxide. Such transformants showed morphological alterations and induced carcinomas when transplanted into nude mice, whereas primary human epidermal keratinocytes treated with these chemical carcinogens failed to show any evidence of transformation. This in vitro system may be useful in assessing environmental carcinogens for human epithelial cells and in detecting new human oncogenes.

Topics: 4-Nitroquinoline-1-oxide; Adenoviruses, Human; Animals; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Epidermal Cells; Humans; Keratins; Methylnitronitrosoguanidine; Mice; Mice, Nude; Neoplasm Transplantation; Nitroquinolines; Oncogenes; Simian virus 40; Skin Neoplasms

Recently, we have shown that transformation of human keratinocytes by SV40 virus induces the re-expression of characters found in fetal epidermis and monostratified epithelia. In the present study, TPA was found to alter some features of the human keratinocyte phenotype in a similar manner to SV40 transformation. Indeed, 12-O-tetradecanoyl-13-phorbol acetate (TPA) treatment induced the expression of cytokeratin no. 8, recognized by the monoclonal antibody TROMA-1, which is present in fetal epidermis and/or monostratified epithelia only, and fibronectin expression. However, TPA and SV40 transformation had specific non-overlapping effects. For example, TPA did not prevent terminal differentiation and stratification, as SV40-transformation did, but stimulated these processes. Moreover, TPA was found to induce additional changes in SV40-transformed keratinocytes. In particular it provoked the individualization of cells within the colonies. This effect was seen as little as 1 h after treatment and was reversible. This cellular alteration was accompanied by the reorganization of actin and by a decrease in the number of desmosomes; these changes were not observed after treatment of normal keratinocytes with TPA. These observations lead to the conclusion that TPA is able to trigger cellular responses which cannot be induced by SV40 products alone, but that TPA and some SV40 products can cooperate to elicit new responses, which could reflect a higher state of malignancy.

Topics: Actins; Cell Line; Cell Transformation, Viral; Cytoskeleton; Desmosomes; Fibronectins; Fluorescent Antibody Technique; Humans; Keratins; Phorbols; Simian virus 40; Skin; Tetradecanoylphorbol Acetate

Human cell lines obtained after Epstein-Barr virus transformation of lymphocytes from seven patients with bullous diseases (Bullous pemphigoid, Pemphigus) and five controls were screened for the production of autoantibodies against skin antigens. In five out of seven patients, the culture supernatants tested by indirect immunofluorescence on frozen sections of normal human skin and rabbit lip showed the production of autoantibodies with different specificities: basal epidermal cells, whole epidermis, Merkel cells, fibroblasts endothelial cells, etc. All autoantibodies were of IgM class and reacted with intracellular structures. Some of them were further tested by immunoblotting against epidermal keratins and were found to react with the main human epidermal keratins (56 to 67 kDa). In contrast, even when patients had circulating autoantibodies, no supernatant showed any reactivity against the antigens usually involved in these diseases, i.e., the dermoepidermal junction or the intercellular spaces of epidermis. Supernatants from controls did not show any reactivity by immunofluorescence. The results demonstrated that human lymphoid cell lines obtained from patients with bullous diseases elicited the production of anti-intermediate filament autoantibodies known to occur spontaneously in normal patients. It is suggested that this phenomenon may be linked to the blistering conditions that provoke tissue destruction.

Topics: Animals; Antibodies, Monoclonal; Autoantibodies; B-Lymphocytes; Cell Transformation, Viral; Cells, Cultured; Fluorescent Antibody Technique; Herpesvirus 4, Human; Humans; Intermediate Filaments; Keratins; Molecular Weight; Pemphigoid, Bullous; Pemphigus; Rabbits; Skin Diseases, Vesiculobullous; Vimentin

Binding of low-density lipoproteins (LDL) to the plasma membrane and internalization of low-density lipoprotein receptor complexes were investigated in an epithelial tumor cell derived from the tongue (SCC25) and in SV40-transformed keratinocytes (SVK14 cells). For light microscopic studies an immunofluorescence technique with antiapoprotein B as well as conjugation procedure by which a fluorochrome 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanide (DIL) was conjugated with LDL (LDL-DIL) was used. Binding of LDL to the plasma membrane at 4 degrees C was observed in most SCC25 cells but not in SVK14 cells. The internalization of LDL-DIL was absent in SVK14 cells and was excessive in SCC25 cells. In SCC25 cells, internalization of the LDL-DIL particles was heterogeneously distributed over various cells. When a pulse-chase experiment was performed with LDL-DIL, less LDL was internalized into the SCC25 cells in comparison with a continuous label experiment. For the ultrastructural studies LDL conjugated with colloidal gold was used. In the binding experiments at 4 degrees C most LDL-gold particles were attached to the plasma membrane outside coated pits. During internalization experiments with LDL-gold particles it was observed that within 5-15 min at 37 degrees C several LDL-gold particles were seen in electron-dense structures near the plasma membrane. The electron-dense structures containing LDL-gold, as observed after an internalization period of 5-15 min, may represent the first endosomal compartment as described for transferrin receptors in A431 cells. After a period of 30 min at 37 degrees C the LDL-gold particles were observed in electron-lucent vesicles (multivesicular bodies) and dense bodies. However coated vesicles containing LDL-gold particles were seen sporadically. It is concluded that the route of internalization of LDL into the SCC25 cells differs from that of other cell types. No internalization of LDL gold was found in SVK14 cells, thus, in this respect, the SVK14 cells resemble normal keratinocytes. The morphologic data are in good agreement with biochemical studies published earlier (Ponec M et al, J Invest Dermatol 83:436-440, 1984). Both investigations suggest that LDL receptor activity is modulated during the process of terminal differentiation.

Topics: Carcinoma, Squamous Cell; Cell Transformation, Viral; Cells, Cultured; Endocytosis; Epidermis; Gold; Humans; Keratins; Lipoproteins, LDL; Microscopy, Electron; Receptors, LDL; Simian virus 40

The expression and properties of pemphigoid antigen of SV40-transformed human keratinocytes were studied. By indirect immunofluorescence, SV40-transformed keratinocytes in passage 80-85 expressed the pemphigoid antigen as coarsely granular perinuclear fluorescence. To characterize this antigen, NP40 extracts of cells labeled with [14C]amino acids were immunoprecipitated using sera of 8 patients: bullous pemphigoid (6 patients), chronic localized pemphigoid (1 patient), and drug-induced lichen planus pemphigoides (1 patient). These immunoprecipitates were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis and then fluorographed. All 8 sera precipitated a protein of Mr 240K, while normal human sera did not precipitate this protein. These results indicate that SV40-transformed human keratinocytes synthesize pemphigoid antigen, and that autoantibodies in the sera of pemphigoid patients with different clinical features identify the same antigen of Mr 240K in these cells.

Topics: Antigen-Antibody Reactions; Antigens; Autoantigens; Cell Transformation, Viral; Epidermis; Fluorescent Antibody Technique; Humans; Infant, Newborn; Keratins; Lichen Planus; Pemphigoid, Bullous; Pemphigus; Precipitin Tests; Simian virus 40

Transformation of normal keratinocytes by simian virus 40 (SV 40) leads to the establishment of epithelial cell lines that can be cultured in the absence of the feeder layer and do not become senescent in culture. The SVK14 cell line developed by Taylor-Papadimitriou et al can serve as a model for study of the modification of various cellular processes by certain pharmacologic and physiologic agents, because these cells resemble normal keratinocytes with respect to a variety of parameters related to proliferation and differentiation, as follows: The SVK14 cells show the same ability to form ionophore-induced cross-linked envelopes that is strongly suppressed when the calcium level in the culture medium is reduced. When cultured in a high-calcium medium, both cell types showed a high rate of de novo cholesterol synthesis that was independent of the extracellular lipoprotein concentration. Cells cultured in a low-calcium medium had a much lower rate of cholesterol synthesis, but this rate increased markedly in cells preincubated in lipoprotein-deficient (LPDS) medium and decreased again with the addition of increasing amounts of low-density lipoprotein (LDL). Both types of cell showed decreased ability to bind epidermal growth factor (EGF) and LDL during calcium-induced differentiation, the expression of LDL and/or EGF receptors being high in low-calcium and low in high-calcium cells. Addition of etretinate (0.05-5.0 microM) suppressed cholesterol synthesis and strongly stimulated triglyceride synthesis in both cell types without significantly affecting the rate of protein synthesis. The addition of small doses of glucocorticoids (10(-9) to 10(-6) M) led to stimulation and higher doses (up to 5 X 10(-5) M) to inhibition of cell proliferation.

Topics: Calcium; Cell Differentiation; Cell Division; Cell Transformation, Viral; Cells, Cultured; Cholesterol; Epidermal Cells; Epidermal Growth Factor; Humans; Keratins; Lipid Metabolism; Lipoproteins, LDL; Male; Protein Biosynthesis; Receptors, Glucocorticoid; Simian virus 40

We analyzed the state of the genomic DNA of the papovavirus SV40 in human keratinocytes as viral-infected cells gradually acquired a transformed phenotype over time. Initially, the vast majority of the viral DNA is maintained either in a full-length supercoiled form or as truncated subgenomic fragments with little evidence of integration. However, analyses of clonal populations revealed great heterogeneity and instability of the viral DNA, and we were able to isolate one clonal subpopulation in which integrated forms of the virus appeared to predominate. Similarly, uncloned populations eventually ceased production of the "free" viral DNA after several years in culture and instead came to display tandemly repeated SV40 copies at a single host integration site. Interestingly, Bg1 II digestion of host DNA generated restriction fragments containing the integrated SV40 DNA, which were of differing sizes in cultures at the 144th vs the 163rd serial passage suggesting modification or rearrangement of sequences at or near the integration site. Host sequences flanking the integrated viral DNA at the 163rd serial passage have been isolated on restriction fragments generated by Eco RI, Bam HI, and Hpa II digestion. These analyses suggest that the integrated virus is linearized near the Bg1 I site and contains a large deletion in the SV40 early region at one of the viral-host junctions.

Topics: Cell Line; Cell Transformation, Viral; Clone Cells; DNA Restriction Enzymes; DNA, Viral; Epidermal Cells; Genes, Viral; Humans; Keratins; Nucleic Acid Hybridization; Simian virus 40

Previous reports from this laboratory indicate that cultured simian virus 40 (SV40)-transformed human keratinocytes express keratin proteins characteristic of simple epithelia that are not found in their untransformed counterparts. In this study we show by in vitro translation and RNA transfer blot analysis that the altered keratin synthesis reflects changes in the abundance of specific keratin mRNAs. SV40-transformed keratinocytes have a reduced abundance of transcripts for 58-, 56-, 52-, 50-, 48-, and 46-kDa keratin species, compared with uninfected cultured keratinocytes, but express significant levels of transcripts for 52-, 45-, and 40-kDa keratins, typical of simple epithelia. The SV40-transformed cells also express mRNA for a 48-kDa keratin that is unique to SV40-transformed keratinocytes. Analysis of the keratin genome with keratin-specific cDNAs as probes indicates that the changes in keratin transcription are not correlated with gross rearrangements of the keratin genome. These results suggest that analysis of viral transformation of cultured keratinocytes affords a novel approach to study mechanisms regulating keratin gene expression.

Topics: Cell Transformation, Viral; Cells, Cultured; DNA Restriction Enzymes; Epithelial Cells; Epithelium; Gene Expression Regulation; Genes; Humans; Keratins; Protein Biosynthesis; RNA, Messenger; Simian virus 40; Transcription, Genetic

BALB-/MK-2 mouse epidermal keratinocytes required epidermal growth factor for proliferation and terminally differentiated in response to high Ca2+ concentration. Infection with retroviruses containing transforming genes of the src and ras oncogene families led to rapid loss of epidermal growth factor dependence, in some cases, accompanied by alterations in cellular morphology. The virus-altered cells continued to proliferate in the presence of high levels of extracellular calcium but exhibited alterations in normal keratinocyte terminal differentiation that appear to be specific to the particular oncogene. These alterations bore similarities to abnormalities in differentiation observed in naturally occurring squamous epithelial malignancies.

Topics: Animals; Calcium; Cell Differentiation; Cell Division; Cell Transformation, Viral; Cells, Cultured; Epidermal Cells; Epidermal Growth Factor; Epidermis; Keratins; Mice; Oncogenes; Protein-Tyrosine Kinases; Retroviridae

We have studied the synthesis and distribution of fibronectin in human epidermal keratinocytes infected by SV40, a system in which the acquisition of transformed properties occurs in a sequential and progressive manner. Immunofluorescence studies showed that cultured uninfected keratinocytes do not exhibit fibronectin on the superficial cell surface, but that virus-infected cells come to display superficial fibronectin-containing cables in a density-dependent manner after a certain point in the transformation process. In contrast, organized arrays of fibronectin-containing fibrils associated with the cell-substrate attachment complex were seen in uninfected keratinocytes and in virus-infected cells at all stages of the transformation process. Studies of fibronectin synthesis using metabolic labelling of cell proteins with 35S methionine showed that viral infection caused a striking increase in overall fibronectin synthesis, although with a much higher proportion of newly synthesized fibronectin being secreted into the cell culture medium than in the case of the uninfected cells.

Topics: Cell Line; Cell Transformation, Viral; Electrophoresis, Polyacrylamide Gel; Epidermal Cells; Extracellular Matrix; Fibronectins; Fluorescent Antibody Technique; Humans; Infant, Newborn; Keratins; Male; Simian virus 40

Transformation of human epidermal keratinocytes by the oncogenic virus SV40 is a stage-specific process in which normal patterns of differentiation are progressively altered over time following infection. Within the context of this scheme, we examined the keratins produced by the infected cells. Immunofluorescence studies indicated that viral infection led to the formation of variant cells visibly lacking the normal keratin cytoskeleton after about 10-15 serial passages (60-90 cell generations) post infection. Analyses of variant cell formation in clonal populations grown on palladium islands revealed that the variants were derived within 2-3 cell divisions from cells containing an apparently normal keratin cytoskeleton, but that variant formation depended upon cell density. Immunoprecipitation of 35S-methionine labelled keratins from the infected keratinocytes revealed a gradual loss of the normal 46, 50, 56 and 58Kd keratin species over a period of many months after infection. The loss of the normal keratins was accompanied by the appearance of at least two species in the 48-52Kd size range not present in uninfected cells and the enhancement of a third, 40Kd, protein quite early after infection. Analysis of the altered keratin patterns on two-dimensional acrylamide gels using either isoelectric focusing (IEF) or non-equilibrium pH gradient electrophoresis (NEPHG) along the first dimension showed that the infected cells produced basic keratins which increased in relative abundance as cells became more transformed with serial passage including at least five isoelectric forms not seen in uninfected cells. Translation of poly A+ RNAs from the infected cells indicated that the altered keratin synthesis probably reflects changes in the translatable mRNA pool.

Topics: Cell Count; Cell Division; Cell Transformation, Viral; Cells, Cultured; Cytoskeleton; Epidermal Cells; Epidermis; Fluorescent Antibody Technique; Humans; Keratins; Molecular Weight; Phenotype; Poly A; Protein Biosynthesis; RNA; RNA, Messenger; Simian virus 40

Seventeen cases of verrucous carcinoma of the oral cavity were reviewed. It was found that cytologic features generally associated with viral modification were observed in 15 of these cases. This finding suggests that viruses may play some role in the pathogenesis of verrucous carcinoma. The hypothesis that an opportunistic, persistent virus may act in concert with frank carcinogens to promote the development of verrucous carcinoma is discussed.

Topics: Adult; Aged; Animals; Carcinoma, Papillary; Cell Nucleus; Cell Transformation, Neoplastic; Cell Transformation, Viral; Epithelium; Female; Humans; Hyperplasia; Keratins; Male; Middle Aged; Mouth Neoplasms; Tumor Virus Infections

Infection of human epidermal keratinocytes by the oncogenic virus SV40 leads to progressive inhibition of the normal differentiation process in vitro. Treatment of infected cells with 5-azacytidine (5-aza-CR) over a 24-h period produced a striking enlargement and pronounced flattening of cells within 5-7 days following removal of the agent. This morphological change was accompanied by a several-fold increase in the number of cells staining positively for the cell envelope precursor protein, involucrin, and in the exfoliation of cornified envelope bearing cells from the monolayer. The drug-treated cultures at high passage levels were stained by immunofluorescence using monoclonal antibodies to keratin classes associated with different epidermal layers. These experiments revealed that 5-aza-CR caused the re-expression of two keratin classes (suprabasal and stratum corneum-associated), whose synthesis had been suppressed during the transformation process. 5-Aza-CR also brought about re-expression of 58 and 56 kD keratin markers of epithelial keratinization and stratification, as well as of 40 and 49-52 kD keratin markers of viral transformation. However, the responsiveness to the drug was gradually lost over time following infection.

Topics: Azacitidine; Cell Differentiation; Cell Transformation, Viral; Cells, Cultured; Floxuridine; Fluorescent Antibody Technique; Humans; Infant, Newborn; Keratins; Kinetics; Male; Simian virus 40; Skin; Skin Physiological Phenomena

SV40-transformation as well as treatment with tumor promoters produce alterations in morphology, differentiation and keratinization of human keratinocytes. Two cell lines of SV40-transformed keratinocytes and primary cultures of keratinocytes treated with the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA) were found to contain an additional protein of 52.5 kD molecular weight (MW). This protein was identified by its reactivity with the monoclonal antibody TROMA-I as being keratin no. 8, a keratin normally present only in simple epithelia. Since this keratin is present in fetal epidermis but disappears gradually when fetal skin becomes multilayered after week 13 of development (Moll et al., Differentiation 23 (1982) 170. [23]), it suggests that SV40 virus and TPA are able to induce in human keratinocytes the reexpression of fetal characters.

Topics: Cell Line; Cell Transformation, Viral; Cells, Cultured; Female; Fetus; Fluorescent Antibody Technique; Humans; Infant, Newborn; Keratins; Male; Molecular Weight; Phorbols; Pregnancy; Simian virus 40; Skin; Tetradecanoylphorbol Acetate

To obtain more information on differences in cellular behavior during the differentiation process, a number of types of epithelial cells with and without a defect in cornified envelope formation were compared as to the regulation of intracellular cholesterol synthesis by low-density lipoprotein (LDL) and the uptake and degradation of [125I]LDL. The following cells were cultured: normal skin fibroblasts (F), normal (K) and SV 40 transformed (SVK14) keratinocytes, and a number of squamous carcinoma cell (SCC) lines in which the defective terminal differentiation was found to occur in the following order of intensity: SCC-12F2 less than SCC-25 approximately equal to SCC-15 less than SCC-12B2 less than SCC-4. Compared with normal human fibroblasts, most of the cells under study showed a defective response to changes of the extracellular serum LDL concentration. The degree of inducibility of cholesterol synthesis after the cells were deprived of extracellular sources of cholesterol as well as the degree of the LDL-induced suppression of the intracellular cholesterol synthesis in cells preincubated in medium supplemented with lipoprotein-deficient serum decreased in the following order: F greater than SCC-4 greater than SCC-15 approximately equal to SCC-25 greater than SCC-12B2 congruent to SCC-12F2 greater than SVK14 approximately equal to K. A defect in LDL metabolism was found to be responsible for the partial or complete failure of LDL to regulate the cholesterol metabolism, because when sterol was delivered to all cell types in artificial nonlipoprotein form (i.e., as 25-hydroxycholesterol) a marked suppression of cholesterol synthesis was observed. For all SCC lines tested except SCC-12B2 good correlation was found between the degree of LDL-induced suppression of cholesterol synthesis and the decreasing ability of cells to differentiate into squames or cornified envelope-forming cells. The transformation of keratinocytes by SV 40 virus did not lead to any change in the response of the cells to changes in the extracellular LDL concentration since both the normal and the transformed keratinocytes showed the same response to LDL (i.e., no response).

Topics: Carcinoma, Squamous Cell; Cell Differentiation; Cell Line; Cell Transformation, Viral; Cells, Cultured; Cholesterol; Culture Media; Epidermal Cells; Epidermis; Fibroblasts; Humans; Hydroxycholesterols; Keratins; Lipoproteins, LDL; Simian virus 40; Skin Neoplasms

Human epidermal cells were transformed with DNA from wild-type SV40 virus or with DNA from a temperature-sensitive A mutant (tsA209). The SV40-transformed cells differed from nontransformed cells in their morphologic appearance, growth properties, and expression of certain characteristics associated with differentiation. The transformed cells were more variable in size and shape than their nontransformed counterparts and were less stratified and less keratinized. While the growth properties of the cells were similar under optimal growth conditions, the transformed cells could be propagated under stringent growth conditions that did not support the growth of nontransformed human epidermal cells. The transformants still required a 3T3 feeder layer for growth, remained anchorage dependent as assayed in soft agar, and were not tumorigenic in athymic nude mice. The expression of certain differentiated functions of the human epidermal cell, the presence of keratins and cross-linked envelopes, was decreased in the transformed cells, and these functions could be restored at the nonpermissive temperature in the tsA209 transformed cells.

Topics: Cell Adhesion; Cell Differentiation; Cell Division; Cell Transformation, Viral; Cells, Cultured; Epidermal Cells; Humans; Keratins; Molecular Weight; Simian virus 40

We have examined the growth of three epitheliotropic viruses in cultures of human epidermal keratinocytes: herpes simplex virus (HSV) type 1, adenovirus type 2 (Ad-2), and human papillomavirus (HPV) type 1. Differences were noted in the level of expression of each virus, and these differences may be related to a dependency or lack of dependency on keratinocyte differentiation for complete viral growth. Of the three viruses studied, HSV was the only one to replicate productively in all cells of the culture. Its expression was independent of keratinocyte differentiation. This is unlike Ad-2, which infected all cells in the culture but replicated productively only in the suprabasal cells. Basal keratinocytes were shown to be infected, but for unknown reasons, they appeared in most instances to be nonpermissive for Ad-2 replication. Infected basal keratinocytes became permissive when they reached a suprabasal position. Ad-2 appears to require keratinocyte differentiation for full expression in culture. Following infection with HPV, cultured keratinocytes showed no evidence of productive replication. However, 50 to 250 copies of HPV DNA could be detected in each cell (average) as stable nonintegrated molecules. Viral DNA replication has been shown to occur in the younger cells and not in the older, more differentiated keratinocytes. The failure of HPV to be fully expressed in culture may be related, in part, to incomplete differentiation of the keratinocyte in vitro. The major conclusions of this study are (1) that keratinocyte differentiation is likely to play a role in the expression of some epitheliotropic viruses in culture, and (2) that keratinocyte differentiation may be a factor in the pathogenesis of certain viral diseases of keratinizing epithelia.

Topics: Adenoviridae; Cell Differentiation; Cell Transformation, Viral; DNA Replication; DNA, Viral; Epidermal Cells; Humans; Infant, Newborn; Keratins; Male; Papillomaviridae; Simplexvirus

Human retinal pigment epithelium (RPE)-derived cell lines were established from RPE-covered choroid tissue fragments, which had been generated by culture on nontissue culture plastic. Two phenotypes were apparent in a given line: (a) a compact cell which formed domes and ultimately melanosomes before being sloughed; and (b) a squamous cell which was often elongated and which bound antibody to human keratins. This latter cell did not become black or form domes. The average number of cell doublings for the 13 lines tested was between 15 and 40 when cultured in a modified Eagle's minimum essential medium containing 10% fetal bovine serum. Cell lines newly established from material that had been in culture for more than 6 months had normal mitotic chromosomes and still developed areas with strongly pigmented cells when refed. Normal human epithelial cell lines of this kind may be useful in studies of cell aging and defining change associated with the development of neural cells from ectoderm.

Topics: Cell Division; Cell Line; Cell Survival; Cell Transformation, Viral; Choroid; Humans; Karyotyping; Keratins; Melanocytes; Pigment Epithelium of Eye; Simian virus 40; Trypsin

A cloned cell line (SVK14) with apparently unlimited growth potential was isolated from simian virus 40 (SV40)-infected human foreskin keratinocytes which did not appear to pass through any obvious 'crisis' (Girardi et al., J. Cell. Comp. Physiol., 1965, 65, 69-84). Indirect immunofluorescence microscopy showed that the transformed cells have the SV40 large T antigen in their nuclei and stain positively with LE61, a monoclonal antibody that reacts with a tonofilament determinant normally only found in non-keratinizing simple epithelia. SVK14 cells can be grown in the absence of 3T3 feeders and show an impaired ability to differentiate into squames, and this impairment becomes more marked with passage. At later passages the cells acquire the ability to form colonies in agar and to produce a factor with mitogenic activity which stimulates DNA synthesis in quiescent 3T3 cells. Concomitantly, the SVK14 cells become less sensitive to the growth inhibitory effect of human alpha interferons.

Topics: Cell Differentiation; Cell Division; Cell Line; Cell Transformation, Viral; Cytoskeleton; Epithelium; Growth Substances; Humans; Interferons; Keratins; Male; Neoplasms, Experimental; Simian virus 40

The keratin polypeptide composition of different types of warts was studied by means of SDS polyacrylamide gel electrophoresis. It was composed of five main polypeptides, similar to those found in normal epidermis (mol. wt. 67K to 55K) and an additional polypeptide (72K) was often detected. The distribution of each polypeptide was expressed as percentage of total keratins in the different samples. The most characteristic feature observed in warts was the marked decrease of the 67K polypeptide. There were increased amounts of the 67K-63K proteins and some difference was observed in the distribution of these proteins in the different types of warts. Thus, the viral infection seems mainly to modify the proteins which are only involved in the latest stages of the differentiation of keratinocytes.

Topics: Cell Transformation, Viral; Electrophoresis, Polyacrylamide Gel; Humans; Keratins; Papillomaviridae; Peptide Biosynthesis; Warts

The epidermal cells isolated from 14-day chicken embryo shank skin epidermis were infected in vitro with Rous sarcoma virus (RSV). Within a few weeks, rapidly growing colonies of epithelial cells appeared among the sea of transformed fibroblastic cells. When isolated and subcultured, these cells were found to possess typical markers of skin epidermis. The presence of major keratin and typical epithelial cell type morphology strongly suggested that these cells were transformed epidermal cells retaining their differentiated characteristics but having the capacity to propagate in cell culture. If RSV tsNY68, an RSV mutant having a temperature lesion in the src gene, was used, similar transformed epidermal cells were obtained at 36 degrees C (permissive temperature). At the nonpermissive temperature (41 degrees C) the growth rate of these cells decreased and additional keratin species appeared. At 41 degrees C the cells were flattened and lost the refractivity in their peripheries. All the keratins which are synthesized at the nonpermissive temperature were present in normal differentiated shank skin of 19-day old chick embryo. These cells also had "cornified envelop," indicating extensive differentiation. Viral production was as efficient as transformed fibroblasts during the rapid growth phase, while it declined significantly after the cells reached confluency, exhibiting the differentiated characteristics. Since no normal epidermal cells could be cultured under our experimental conditions, these results represent examples in which the src gene is essential for propagation of differentiated cells in cell culture while it abolishes only a part of differentiated characteristics.

Topics: Animals; Avian Sarcoma Viruses; Cell Transformation, Viral; Cells, Cultured; Chick Embryo; Electrophoresis, Polyacrylamide Gel; Epidermis; Hot Temperature; Keratins; Molecular Weight; Skin; Virus Replication

Human epidermal keratinocytes were infected by simian virus 40 in vitro. The structure of the developing keratinocyte colony reflects the spatial separation of cell division and keratinization in intact skin; thymidine-incorporating cells were primarily localized at the colony periphery whereas nondividing, histologically differentiated cells accumulated in the interior. Viral infection produced a dramatic increase in the size of the proliferative population as, simultaneously, differentiation was reduced in the colony interior. These changes were manifest when simian virus 40 T-antigen synthesis was detectable in only a small percentage of the cells; differentiation became increasingly density dependent as the percentage of T-antigen-positive cells rose over serial passage. The disruption of the normal pattern of growth/differentiation localization coincided with a loss of dependence on serum for growth, but preceded the appearance of other virus-induced properties associated with transformation; i.e., the ability to form colonies in soft agar and independence of growth from fibroblasts.

Topics: Antigens, Neoplasm; Antigens, Viral; Cell Differentiation; Cell Division; Cell Transformation, Viral; Cells, Cultured; Epidermal Cells; Epidermis; Humans; Keratins; Simian virus 40