involucrin and Lung-Neoplasms

Epidemiological evidence suggests that cigarette smoke induces squamous metaplasia in human tracheobronchial epithelium that can progress to lung squamous carcinoma. But it is not well understood how tracheobronchial epithelial cells transduce the signals that mediate cigarette smoke-induced squamous differentiation or squamous metaplasia. In the present study, we found that in vitro cigarette smoke components notably inhibited glycogen synthase kinase 3 (GSK3) and induced the expression of involucrin, a marker of squamous differentiation. The inactivation of GSK3 by two highly selective inhibitors, lithium and SB216763, also significantly enhanced involucrin expression in cultured porcine tracheobronchial epithelial cells (PTBECs). Moreover, we demonstrated that cigarette smoke components significantly promoted activator protein-1 (AP-1) binding activities to the upstream regulatory region of involucrin gene, and similar results were observed by further studies through using GSK3 inhibitors to imitate the effects of cigarette smoke components. Taken together, we conclude that GSK3 is involved in involucrin expression induced by cigarette smoke in PTBEC probably via negatively regulating AP-1 activity, implying a possible mechanism responsible for squamous differentiation induced by cigarette smoke.

Topics: Animals; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Enzyme Inhibitors; Gene Expression; Glycogen Synthase Kinase 3; Indoles; Lithium; Lung Neoplasms; Maleimides; Metaplasia; Precancerous Conditions; Protein Precursors; Respiratory Mucosa; Signal Transduction; Smoke; Swine; Transcription Factor AP-1

Overwhelming evidence has demonstrated tobacco smoke (TS) is causally associated with various types of cancers, especially lung cancer. Sustained epithelial cell hyperplasia and squamous metaplasia are considered as preneoplastic lesions during the formation of lung cancer. The cellular and molecular mechanisms leading to lung cancer due to TS are not clear. Mitogen-activated protein kinases (MAPK)/activator protein-1 (AP-1) can be activated by various stimuli and play a critical role in the control of cell proliferation and differentiation. To date, information on the response of the MAPK/AP-1 pathway during hyperplasia and squamous metaplasia induced by TS is lacking. We therefore investigated the effects of TS on the development of epithelial hyperplasia and squamous metaplasia, regulation of MAPK/AP-1 activation, and expression of AP-1-regulated cell cycle proteins and differentiation markers in the lungs of rats. Exposure of rats to TS (30 mg/m(3) or 80 mg/m(3), 6 h/day, 3 days/week for 14 weeks) dramatically induced cell proliferation and squamous metaplasia in a dose-dependent manner, effects that paralleled the activation of AP-1-DNA binding activity. Phosphorylated ERK1/2, JNK, p38 and ERK5 were significantly increased by exposure to TS, indicating the activation of these MAPK pathways. Expression of Jun and Fos proteins were differentially regulated by TS. TS upregulated the expression of AP-1-dependent cell cycle proteins including cyclin D1 and proliferating cell nuclear antigen (PCNA). Among the AP-1-dependent cell differentiation markers, keratin 5 and 14 were upregulated, while loricrin, filaggrin and involucrin were downregulated following TS exposure. These findings suggest the important role of MAPK/AP-1 pathway in TS-induced pathogenesis, thus providing new insights into the molecular mechanisms of TS-associated lung diseases including lung cancers.

Topics: Animals; Cell Proliferation; Cyclin D1; Enzyme Activation; Filaggrin Proteins; Hyperplasia; Intermediate Filament Proteins; JNK Mitogen-Activated Protein Kinases; Keratins; Lung Neoplasms; Male; Membrane Proteins; Metaplasia; Mitogen-Activated Protein Kinases; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Proliferating Cell Nuclear Antigen; Protein Precursors; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Rats; Rats, Inbred WKY; Signal Transduction; Smoking; Transcription Factor AP-1

It has been reported previously in cases of adenosquamous carcinoma of the lung in Okinawa, a subtropical island 2000 km south of mainland Japan, that the squamous cell carcinoma components were positive for human papillomavirus (HPV) by non-isotopic in situ hybridisation (NISH). The adenocarcinoma cells adjacent to the squamous cell carcinoma components were enlarged and also positive for HPV. This is thought to indicate that after adenocarcinoma cells are infected with HPV, they undergo morphological changes, and that "squamous metaplasia" follows. In this present study, the effects of HPV transfection into adenocarcinoma cells were examined. The relation between the region expressing the HPV gene and squamous metaplasia was also studied.. Plasmid pBR322 containing HPV type 16 (HPV-16) was transfected into cultured colonic adenocarcinoma (DLD-1) and lung adenocarcinoma (PC-14) cells using the calcium phosphate method. Neomycin was used as a selection marker. The presence of HPV E1, E2, E4, E5, E6, E7, L1, and L2 mRNAs and also transglutaminase 1, involucrin, cyclin dependent kinases (CDKs), cyclins, caspases, apoptosis inducing factor, DNase gamma, Fas, and Fas ligand mRNAs in HPV transfected cells was investigated by means of reverse transcription polymerase chain reaction (RT-PCR). The G0-G1 cell population was analysed by flow cytometry. Morphological examination under light and electron microscopes was also carried out.. The virus transfected cells showed squamous metaplasia when they were injected into severe combined immunodeficient mice, expressing the high molecular weight keratin (Moll's number 1 keratin) and involucrin molecules immunohistochemically, and involucrin and transglutaminase I mRNAs by RT-PCR. The squamous metaplasia was most conspicuous in the HPV transfected DLD-1 cell when compared with HPV transfected PC-14 cells. Squamous metaplasia was most clearly demonstrated in one HPV transfected DLD-1 cell clone, which expressed not only E2 but also E6-E7 fusion gene mRNA. Viral L1 mRNA expression was absent in HPV transfected cell clones, and was not related to squamous metaplasia. The growth rate of HPV transfected cells was reduced. Transfection of the virus into the cultured adenocarcinoma cells increased the G0-G1 cell population greatly, as assessed by flow cytometer analysis. Furthermore, in the virus transfected cells, apoptosis was also observed by means of the terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labelling method.. HPV transfection into adenocarcinoma cells induced clear squamous metaplasia. One of the HPV transfected cell clones that expressed E2 and E6-E7 fusion gene mRNA showed the squamous metaplasia particularly clearly, and apoptosis was also demonstrated.

Topics: Adenocarcinoma; Animals; Apoptosis; Blotting, Western; Carcinoma, Squamous Cell; Cell Cycle; Cell Differentiation; DNA, Viral; Humans; Keratins; Lung Neoplasms; Metaplasia; Mice; Mice, SCID; Neoplasm Proteins; Neoplasm Transplantation; Papillomaviridae; Protein Precursors; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Viral; Transfection; Tumor Cells, Cultured

Fifty samples of lung tissue from patients with non-small cell lung cancer were analyzed for the expression and localization of biomarkers related to squamous differentiation and programmed cell death. These markers include tissue transglutaminase (tTG), keratinocyte transglutaminase (kTG), involucrin, loricrin, and Bcl-2. We found that all of these markers are overexpressed in tumors as compared with histologically normal lung epithelium, where expression is minimal. Expression of the oncoprotein, Bcl-2, increased starting in squamous metaplasia and remained elevated in all lesions, including frank carcinoma. In contrast, expression of the other markers was elevated in the histologically abnormal noninvasive lesions but was decreased somewhat in invasive malignancy. In addition, we found that tTG, kTG, and Bcl-2, when expressed, were detected in mutually exclusive areas. These findings suggest that (1) these markers may prove useful, with more extensive testing and clinical correlation, in predicting risk for the development of lung cancer; and (2) pulmonary carcinogenesis may result from the failure of differentiation and programmed cell death mechanisms in the presence of oncogene overexpression rather than through oncogene/tumor suppressor gene abnormalities alone.

Topics: Apoptosis; Biomarkers; Carcinoma, Non-Small-Cell Lung; Cell Differentiation; Humans; Immunoenzyme Techniques; Lung; Lung Neoplasms; Membrane Proteins; Pilot Projects; Protein Precursors; Proto-Oncogene Proteins c-bcl-2; Transglutaminases

To investigate the presence of human papillomavirus (HPV) DNA in adenosquamous carcinoma of the lung--which is relatively common in Okinawa but not in mainland Japan--and examine its histological features.. Of 207 cases where primary lung cancers were surgically removed between January 1995 and June 1997 in Okinawa, 23 were adenosquamous carcinoma. HPV was detected by non-isotopic in situ hybridisation (NISH) and polymerase chain reaction (PCR) amplification with primers specific for E6 and E7 regions of the HPV genome. PCR products were analysed by Southern blotting. Immunohistochemical determination of high molecular weight cytokeratin (HMC) and involucrin was also carried out.. 18 cases were positive for HPV DNA by PCR and NISH. HPV types 6, 11, 16, and 18 were found. Seven cases were dual positive for different types of HPV. Using NISH, HPV was also found in the squamous cell components and in neighbouring enlarged adenocarcinoma cells. The HMC and involucrin were demonstrated immunohistochemically in the same areas.. HPV DNA was found in a high proportion (78.3%) of adenosquamous carcinomas in Okinawa, a region where HPV has previously been shown to be prevalent in squamous cell carcinoma of the lung. The adenocarcinoma cells adjacent to the squamous cell carcinoma component were enlarged and positive for HPV, HMC, and involucrin. This is thought to indicate the transition from adenocarcinoma to squamous cell carcinoma.

Topics: Aged; Aged, 80 and over; Base Sequence; Blotting, Southern; Carcinoma, Adenosquamous; DNA, Viral; Humans; In Situ Hybridization; Keratins; Lung Neoplasms; Male; Middle Aged; Neoplasm Proteins; Papillomaviridae; Polymerase Chain Reaction; Protein Precursors

Bronchial epithelial dysplasia is a non-invasive cellular change often associated with physical or chemical injury and considered a pre-neoplastic lesion in the formation of lung cancer. A series of 39 bronchial dysplasias associated with both neoplastic and non-neoplastic lesions were assessed for expression of markers of differentiation by immunocytochemistry and compared with samples of normal bronchial epithelium. The normal bronchial epithelium studied expressed cytokeratins (CKs) 4, 6, 7, 8, 18, and 19 in all cases; CK 13 in 13 cases; and peanut agglutinin (PNA) in seven cases. Involucrin, CK 10, and CK 14 were not observed in the normal bronchial samples. In the dysplastic bronchial biopsies, epithelial staining was observed with epithelial CKs 7, 8, 18, and 19 in all cases; CK 13 was seen in 26 cases; CK 14 in 13 cases; CK 6 in 11 cases; and CK 10 in five cases. In 13 cases of dysplasia, only simple epithelial antigens were identified. Involucrin expression was observed in 17 dysplastic biopsies and PNA in 12. By Fisher's exact test, a significant association between non-severe histological grade of dysplasia and CK 6 expression (P = 0.018) was found. Comparison of the results using the same analysis showed significant correlations between the loss of CK 6 expression (P < 0.001) and the expression of CK 14 (P = 0.008) and involucrin (P = 0.0018) with bronchial dysplasia. These data show that the pattern of differentiation antigen expression in bronchial dysplasia is significantly different from that of the normal bronchial epithelium, but the phenotypic heterogeneity of these lesions is similar to that of bronchial carcinomas.

Topics: Aged; Aged, 80 and over; Antigens, Differentiation; Biomarkers; Bronchi; Cell Differentiation; Epithelium; Humans; Immunoenzyme Techniques; Keratins; Lectins; Lung Neoplasms; Middle Aged; Peanut Agglutinin; Precancerous Conditions; Protein Precursors

Non-small cell lung cancer (NSCLC) is fatal in approximately 90% of all cases due to the failure of systemic therapy, secondary to resistance to chemotherapy. In such malignancies new therapeutic paradigms are needed. One such approach takes advantage of normal physiologic growth regulatory mechanisms, such as terminal cellular differentiation or apoptosis. Suramin, as an antineoplastic drug, has shown efficacy in the treatment of prostate cancer and is capable of promoting differentiation in several human cancer cell lines. Little is known about the differentiating effects of suramin in lung cancer. In the present investigation we evaluated the ability of suramin to induce cross-linked envelope (CLE) formation, as a common marker for squamous differentiation and apoptosis, in three representative human non-small cell lung cancer cell lines: NCI-H226 (squamous), NCI-H358 (bronchoalveolar [adenocarcinoma]), and NCI-H596 (adenosquamous). Among agents that we have tested, suramin demonstrated the unique ability to induce spontaneous CLE formation in the two cell lines with squamous features, NCI-H226 and NCI-H596. Suramin induced CLE formation was accompanied by DNA fragmentation, a marker for apoptosis, in NCI-H596 and NCI-H358, but not in NCI-H226. Stimulation of CLE formation by suramin correlated with the rapid induction of both type II transglutaminase (TG) activity and involucrin expression. These parameters were protein synthesis independent, suggesting posttranslational mechanisms of suramin activity. Induction of differentiation/apoptosis markers by suramin did not correlate with its effect on growth. Modulation of signal transduction is a likely candidate mechanism for suramin activity in lung cancer. The relationship between growth, squamous differentiation, and apoptosis is considered.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Calcimycin; Carcinoma, Adenosquamous; Carcinoma, Squamous Cell; Cell Differentiation; Cell Division; DNA Fragmentation; Enzyme Inhibitors; Humans; Ionophores; Lung Neoplasms; Neoplasm Proteins; Protein Kinase C; Protein Precursors; Putrescine; Suramin; Transglutaminases; Tumor Cells, Cultured

More than 95% of lung cancers occur in the bronchi, appearing as adenocarcinoma, squamous carcinoma, large-cell and small-cell carcinoma, or mixed types. Generally, the least aggressive form is squamous cell lung cancer, suggesting the possibility that promotion of squamous cell differentiation may have therapeutic potential for non-small-cell lung cancer, a disease having no effective systemic therapy. Interferons are a group of glycoproteins with known antiproliferative effects, including the ability to induce differentiation in certain cases.. These studies were conducted to determine whether interferon beta induces squamous cell differentiation in non-small-cell lung cancer in vitro.. NCI-H596 adenosquamous cells were grown to confluence to maximize their differentiation potential. Growth and parameters for squamous differentiation (cross-linked envelope competence, transglutaminase activity, and relative involucrin expression) were then measured when the cells were exposed to various concentrations of interferon beta.. Interferon beta inhibited growth of the NCI-H596 cell line and stimulated envelope competence, involucrin expression, and type 2 transglutaminase activity. Alterations in transglutaminase activity and involucrin expression preceded induction of envelope competence and growth suppression.. Interferon beta suppresses the growth and stimulates markers of squamous differentiation in NCI-H596. While the mechanism(s) for such effects are unknown, the sequence of effects suggests a causal relationship between differentiation induction and subsequent growth suppression.. Interferon beta may have clinical usefulness in squamous differentiation strategies for the treatment of non-small-cell lung cancer. More must be learned about the mechanisms whereby interferons and other biologic agents induce differentiation, and clinical trials will be needed to determine whether in vitro results are pertinent in vivo.

Topics: Apoptosis; Carcinoma, Adenosquamous; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Differentiation; Cell Division; Humans; Interferon-beta; Lung Neoplasms; Membrane Proteins; Neoplasm Proteins; Protein Precursors; Transglutaminases; Tumor Cells, Cultured

The expression of cytokeratins (CK) 1, 4, 5/6, 8, 13, 18, 19 and 20 and involucrin in 42 cases of squamous cell carcinomas from various locations was examined. The tumours expressed CK5/6 in 55%, CK8 in 76%, CK13 in 43% and CK19 in 95% of cases. The CK5/6-positive primary tumours were from uterine cervix, head and neck, lung, skin, oesophagus and urinary bladder, and the CK13-positive primary tumours were from uterine cervix, lung and vulva. Metastatic squamous cell carcinomas from head and neck more frequently expressed CK5/6 and 13, 7/7 (100%) and 6/7 (86%) compared with 3/5 (60%) and 0/5 (0%) in the primary squamous cell carcinomas. Few cases were CK1, CK4 and CK18 immunoreactive. CK20 immunoreactivity was not observed. Involucrin was expressed in 71% of tumours, and most of the involucrin-positive cells were located at the central parts of tumour cell clusters except for one case in which the peripheral cells around tumour cell clusters were positive. Thus, expression of the so-called simple epithelial markers CK8 and CK19 occurs in the majority of squamous cell carcinomas. The absence of CK20 immunoreactivity may be helpful in differential diagnosis.

Topics: Carcinoma, Squamous Cell; Female; Humans; Immunohistochemistry; Keratins; Lung Neoplasms; Lymphatic Metastasis; Mouth Neoplasms; Protein Precursors; Skin Neoplasms; Urinary Bladder Neoplasms; Uterine Neoplasms

Three human lung squamous carcinoma cell lines (NX002, CX140 and CX143) demonstrate features of squamous differentiation including involucrin synthesis and competence to form cornified envelopes. 12-O-Tetradecanoylphorbol 13-acetate inhibits growth of these cell lines and this growth inhibition is associated with enhanced differentiation.

Topics: Antigens, Neoplasm; Carcinoma, Squamous Cell; Cell Differentiation; Cell Division; Humans; Keratins; Lung Neoplasms; Protein Precursors; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured

Although EGF receptor expression is generally elevated in human lung squamous carcinoma, the biological significance of this phenomenon and the role of EGF and TGF-alpha in this disease are poorly understood. We have investigated three human lung squamous carcinoma cell lines (NX002, CX140 and CX143) and have shown, using an antibody (EGFR1) directed against the EGF receptor, that the majority of cells in all three lines express the EGF receptor. Using a ligand binding assay, Scatchard analysis indicated high concentrations (1,300-2,700 fmol mg-1 protein) of a single low affinity binding site (Kd = 3-5 nM) within these lines. Addition of EGF or TGF-alpha at concentrations greater than 0.1 nM resulted in growth inhibition of all three lines and this was associated with an accumulation of cells in the G2/M phase of the cell cycle. Growth inhibitory effects were not explained by an enhancement of cellular differentiation as monitored by involucrin expression and the ability to form cornified envelopes. While the presence of EGF could not be detected in medium conditioned by the NX002 cell line, mRNA for TGF-alpha was detected in all three lines suggesting the possibility of an autocrine loop. These results together with reports of growth inhibition by EGF and TGF-alpha in other systems suggest that EGF and similar molecules might have a growth regulatory role in lung cancer cells and modulation of such may have therapeutic potential.

Topics: Carcinoma, Squamous Cell; Cell Cycle; Cell Division; Cell Line; Culture Media; Epidermal Growth Factor; ErbB Receptors; Humans; Immunohistochemistry; Lung Neoplasms; Protein Precursors; Tetradecanoylphorbol Acetate; Transforming Growth Factor alpha

A previous report has described involucrin as a specific immunohistochemical marker of squamous differentiation in lung carcinomas. The aim of our study was to examine the expression of this antigen in a wide variety of lung tumours, with particular attention to its potential value in the typing of biopsy specimens. We found that immunostaining for involucrin was common in squamous carcinomas but was also found in adenocarcinomas, adenosquamous carcinomas, large cell carcinomas and carcinosarcomas. Small cell carcinomas, carcinoid tumours and mesotheliomas were negative. Contrary to previous claims, this marker appears to have little diagnostic utility in the typing of lung tumours.

Topics: Biomarkers, Tumor; Humans; Immunoenzyme Techniques; Lung Neoplasms; Protein Precursors

Using immunoperoxidase stain for involucrin, 50 well-differentiated adenocarcinomas of the lung were compared with similarly well-differentiated adenocarcinomas of other organs, 30 from the stomach, 30 from the colon, 12 from the pancreas and 12 from the prostate. Thirty (60%) adenocarcinomas of the lung were positive for involucrin; in 24 of 30 cases from 10% to more than 60% of tumor cells were positive and in the remaining 6 cases a few cells were positive. The positive cells included columnar or cuboidal tumor cells as well as some squamoid tumor cells. In contrast, only 4 (4.8%) of 84 tumors in the other organs were involucrin positive. Most of the involucrin positive foci of these four cases seemed to show squamous differentiation. These findings suggest that pulmonary adenocarcinoma is more prone to show squamous differentiation, compared with gastric, colonic, pancreatic and prostatic adenocarcinomas. The result may be applied for the differential diagnosis between primary and metastatic well-differentiated adenocarcinomas in the lung.

Topics: Adenocarcinoma; Cell Differentiation; Colonic Neoplasms; Humans; Immunoenzyme Techniques; Lung Neoplasms; Male; Pancreatic Neoplasms; Prostatic Neoplasms; Protein Precursors; Stomach Neoplasms

Lung carcinoma cell lines were analyzed in culture and in nude mouse xenograft for both morphological appearance and expression of specific proteins that participate in cross-linked envelope formation during normal squamous cell terminal differentiation. Cross-linked envelope formation, induced by artificial influx of millimolar Ca2+ into the cultured cells, was an exclusive trait of squamous, adenosquamous, and mucoepidermoid carcinomas. Small cell lung carcinoma and non-squamous non-small cell lung carcinoma lines, such as adenocarcinoma and large cell carcinoma, were uniformly negative for cross-linked envelope formation. Involucrin, which is incorporated into the cross-linked envelope by the enzyme transglutaminase, was expressed at highest levels in squamous tumors, but several of the non-squamous non-small cell lung carcinoma lines also expressed comparable amounts. On the other hand, transglutaminase activity was consistently higher in squamous as opposed to non-squamous lines, so that in cell culture, a clear contrast between the groups could be observed. A Mr 195,000 protein that is incorporated into cultured human epidermal cell cross-linked envelopes was also observed in some but not all of the squamous lines. Two forms of transglutaminase are expressed in cultured keratinocytes. One of them, tissue transglutaminase, was expressed in the majority of squamous cell lines even though it is not a normal product of squamous differentiation in vivo. Keratinocyte transglutaminase, which is distinct from the tissue form and is normally expressed during terminal differentiation in squamous epithelia. was measurably present in only one of the six squamous cell lines tested. In nude mouse xenografts, keratinocyte transglutaminase, localized immunohistochemically with a biotinylated mouse monoclonal antibody, was again present only in a minority of the squamous lines whereas involucrin was expressed in all. In contrast to involucrin, keratinocyte transglutaminase is not an obligatory component of squamous differentiation in the pulmonary carcinoma cell lines tested. Its expression may be of value in further refining their classification.

Topics: Animals; Biomarkers, Tumor; Carcinoma, Squamous Cell; Cell Differentiation; Cell Line; Cytosol; Humans; Lung Neoplasms; Mice; Mice, Nude; Neoplasm Transplantation; Protein Precursors; Transglutaminases; Transplantation, Heterologous; Tumor Cells, Cultured

Three cell lines of squamous-cell carcinoma and 3 of large-cell carcinoma origin were investigated for the expression of differentiation markers and functional parameters (proliferation, morphology, cornified envelope formation, involucrin staining, transglutaminase activity, adhesiveness and migration) under normal cell culture conditions and after treatment with the tumor promoter phorbol-12-myristate-13-acetate (PMA). Although all original tumors had been described as poorly differentiated by histological grading, we found significant heterogeneity in the expression of differentiation markers in cell culture. A systematic grading of the cell lines became possible only after PMA stimulation. PMA generally increased expression of differentiation markers in cell lines of comparably low grades of differentiation, as indicated by dose-dependent inhibition of proliferation and cloning efficiency, induction of squamous markers, and decreased adhesiveness and cell motility. In contrast, cell lines of apparently higher differentiation by these criteria showed little response to PMA. The results presented show that the assessment of differentiation capacity by comparison of differentiation markers under normal cell culture and PMA-stimulated conditions in established NSCLC cell lines allows for a refined cell culture grading, which might advance the classification and characterization of such cell lines which, otherwise, appear to be very heterogeneous. It may also help to correlate cellular functions with various states of differentiation in vitro.

Topics: Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Adhesion; Cell Line; Cell Transformation, Neoplastic; Chemotaxis; Dose-Response Relationship, Drug; Humans; Immunohistochemistry; L-Lactate Dehydrogenase; Lung Neoplasms; Phorbol Esters; Protein Precursors; Transglutaminases; Tumor Cells, Cultured

Forty-seven surgically resected small cell lung carcinomas (SCLC) were immunohistochemically studied by using antibodies to various neuroendocrine and epithelial markers. SCLC was shown to be subdivided into two categories, with and without the immunoreactive neuroendocrine markers aromatic L-amino acid decarboxylase, gastrin-releasing peptide, serotonin, chromogranin A and neurofilament protein. Neuron-specific enolase (NSE) and creatine kinase BB isoenzyme (CK-BB), which are also considered to be neuroendocrine markers, had a tendency to be widely distributed in the SCLC with a neuroendocrine marker, but the immunoreactivity for both NSE and CK-BB varied in the SCLC without neuroendocrine markers. Therefore they were not included in the classification. Epithelial markers keratin, involucrin and epithelial membrane antigen were frequently observed in the SCLC with neuroendocrine markers, but less so in the SCLC without neuroendocrine markers. The data are discussed briefly in relation to "classic and variant" forms of SCLC in vitro and to a recently proposed histological classification of SCLC.

Topics: Aromatic-L-Amino-Acid Decarboxylases; Carcinoma, Small Cell; Creatine Kinase; Gastrin-Releasing Peptide; Histocytochemistry; Humans; Immunochemistry; Isoenzymes; Keratins; Lung Neoplasms; Neurosecretory Systems; Peptides; Phosphopyruvate Hydratase; Protein Precursors

Human lung tumor cell lines established from the major histological types of lung cancer were examined by immunofluorescent staining techniques for their patterns of intermediate filament (keratin, vimentin, and neurofilament triplet protein) expression. All cell lines examined, both small cell lung carcinoma (SCLC) and non-SCLC (squamous cell carcinoma, adenocarcinoma, large cell carcinoma, and mesothelioma) contained keratin, consistent with their epithelial derivation. These lung carcinoma cell lines also expressed vimentin, the characteristic intermediate filament of mesenchymal cells in vivo. In light of the proposed neuroectodermal origin of SCLC, cell lines were also studied for neurofilament expression. Two of four SCLC tumor cell lines, as well as non-SCLC cell lines, showed no reactivity with antibodies to neurofilament triplet protein. Two of the SCLC cell lines stained weakly with anti-neurofilament antibody. Examination of specific keratin patterns in human lung tumor cell lines by selective immunoprecipitation with keratin antiserum and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that small-sized keratin proteins (Mr 44,000 to 52,000) were present in cell lines derived from SCLC and non-SCLC types of lung cancer. Tumor cell lines exhibiting squamous differentiation by light microscopic criteria (i.e., intracellular keratin, intercellular bridging, "pearl" formation, and/or individual cell keratinization) also displayed a preponderance of intermediate-sized keratins (Mr 57,000 and 59,000) and exhibited another feature of terminal keratinocyte differentiation (cross-linked envelope formation). Mesothelioma cell lines had varying keratin profiles. The presence of keratin proteins in all SCLC cell lines examined argues against a neuroectodermal origin for these tumors and is consistent with the notion that these tumors arise from a common bronchial "stem cell," similar to that from which other types of bronchogenic carcinomas arise.

Topics: Animals; Carcinoma, Squamous Cell; Cell Line; Cell Transformation, Neoplastic; Cytoskeleton; Fluorescent Antibody Technique; Humans; Intermediate Filament Proteins; Keratins; Lung Neoplasms; Mesothelioma; Mice; Microfilament Proteins; Molecular Weight; Protein Precursors; Vimentin

Involucrin is a precursor of the cross-linked envelope protein or marginal band present in human stratum corneum. This study uses immunohistochemical techniques for localization of involucrin in histologic sections from 91 lung tumors in order to evaluate the usefulness of involucrin as a tumor marker in lung neoplasms. Although involucrin is absent from bronchial epithelium, it is expressed in cultured tracheal epithelial cell colonies and in bronchial mucosa with squamous metaplasia. Involucrin was present in all 25 cases of squamous and adenosquamous carcinoma. Staining was focal in 12 cases of squamous cell carcinoma and was most marked in the larger neoplastic cells in the center of squamous cell nests. Only two of 20 cases of adenocarcinoma revealed focal staining for involucrin, and these cases may represent adenosquamous variants. Six of 12 cases of large cell undifferentiated carcinoma stained for involucrin, indicating squamous differentiation, and seven cases of malignant mesothelioma were negative. Isolated involucrin-positive cells were present in two of 16 cases of small cell anaplastic carcinoma and one of 11 carcinoid tumors, identifying variants of neuroendocrine tumors with dual differentiation. Patterns of localization of involucrin in paraffin and frozen sections were compared with staining for cytokeratins in parallel sections. Immunohistochemical localization of involucrin comprises a specific marker for squamous differentiation in lung tumors.

Topics: Adenocarcinoma; Carcinoma; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Humans; Lung Neoplasms; Mesothelioma; Protein Precursors; Staining and Labeling