Gloria A. Niehans

Expression cloning of gastric mucin complementary DNA and localization of mucin gene expression

BACKGROUND & AIMS Secretory mucins play an important role in gastric cytoprotection and are derived from a heterogeneous family of genes. The aim of this study was to determine the specific type and location of mucin gene expression in the human stomach. METHODS Expression cloning was performed by screening a human gastric complementary DNA expression library with antisera against deglycosylated gastric mucin. RNA analysis and immunohistochemistry were used to quantify and localize mucin gene expression. RESULTS Sequencing of positive clones revealed two clones containing tandem repeats. The first contained a 169-amino acid repeat and was named MUC6 (as previously described). The second contained the same 8-amino acid repeat consensus sequence (APTTSTTS) as complementary DNAs previously isolated from a tracheobronchial complementary DNA library and was labeled MUC5 (or MUC5AC). RNA analysis indicated that the gastric epithelium contains high levels of MUC5 and MUC6 messenger RNA with little or no MUC2, MUC3, and MUC4 messenger RNA. Immunohistochemical analysis showed that surface mucous cells of the cardia, fundus, and antrum expressed MUC5 peptide. In contrast, MUC6 peptide expression was limited to mucous neck cells of the fundus, antral-type glands of the antrum and cardia, and Brunners glands of the duodenum. CONCLUSIONS MUC5 and MUC6 represent major secretory mucins in the stomach and are localized to distinct cell types.

Gefitinib in Patients with Malignant Mesothelioma: A Phase II Study by the Cancer and Leukemia Group B

Purpose: The Cancer and Leukemia Group B conducted a phase II study of gefitinib, an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, in patients with previously untreated malignant mesothelioma. Experimental Design: Eligible patients had unresectable pleural or peritoneal mesothelioma, measurable disease, no prior therapy, and performance status 0-1 by Cancer and Leukemia Group B criteria. Gefitinib (500 mg p.o.) was administered once a day for 21 days. Patients underwent restaging after every two cycles. Therapy was continued until disease progression or unacceptable toxicity. Results: The most common grade 3 toxicities were diarrhea (16%) and nausea (12%). Of 43 patients enrolled, 1 patient (2%) had a complete response, 1 patient (2%) had a partial response, 21 (49%) had stable disease lasting two to eight cycles, 15 (35%) had progressive disease, and 5 (12%) had early deaths. One-year survival was 32% [95% confidence interval (CI), 21-50%]. Median survival and failure-free survival were 6.8% (95% CI, 3.5-10.3) and 2.6 months (95% CI, 1.5-4.0), respectively. The 3-month failure-free survival was 40% (95% CI, 25-56%). EGFR expression score by immunohistochemistry done in 28 patients was categorized as low (EGFR 1+ or 2+) or high (EGFR 3+) expression: 97% had EGFR overexpression (2+ or 3+). The median and 3-month failure-free survival were 3.6 months and 40% for those patients with low EGFR expression compared with 8.1 and 40% for those with high EGFR expression. Conclusions: Although 97% of patients with mesothelioma had EGFR overexpression, gefitinib was not active in malignant mesothelioma. EGFR expression does not correlate with failure-free survival.

Immunohistochemistry of germ cell and trophoblastic neoplasms

The immunoprofiles of 121 germ cell and trophoblastic neoplasms were defined, using a battery of antibodies against cytokeratin (CK), vimentin (VIM), epithelial membrane antigen (EMA), placental alkaline phosphatase (PLAP), S‐100 protein, leukocyte common antigen (LCA), UCHL‐1, LN‐2, carcinoembryonic antigen (CEA), neuron‐specific enolase (NSE), chromogranin A, Leu‐7, alpha‐fetoprotein (AFP), alpha‐1‐antitrypsin (AAT), and the beta subunit of human chorionic gonadotropin (BHCG). In addition to 85 neoplasms of testicular origin, the cases included eight ovarian germ cell tumors and 28 extragonadal neoplasms. All tissues had been subjected to formalin fixation and paraffin embedding. Similar immunoreactivity patterns were seen in gonadal and extragonadal neoplasms, gestational and nongestational choriocarcinomas, components of mixed germ cell tumors and their pure counterparts, and metastatic and primary lesions. Placental alkaline phosphatase was a sensitive marker of germ cell differentiation, and expression of this marker in the absence of EMA appeared to be a staining pattern unique to germ cell tumors. Both LCA and S100 were absent in neoplastic germ cells, and thus were useful in differentiating these tumors from malignant lymphoma and malignant melanoma, respectively. Cytokeratin was helpful in distinguishing seminomas/dysgerminomas from nonseminomatous germ cell tumors, although 10% of seminomas showed focal or diffuse cytokeratin reactivity. Finally, 75% of all germ cell neoplasms displayed NSE, calling the specificity of this determinant into question.

The Role of Ilioinguinal Lymphadenectomy and Significance of Histological Differentiation in Treatment of Carcinoma of the Penis

We reviewed retrospectively the medical records of 58 patients treated for squamous cell carcinoma of the penis who were followed for more than 3 years or until they died. Tissue sections from all patients were reviewed. Of 15 patients with stage I disease 11 underwent partial penectomy, and 4 underwent partial penectomy and immediate ilioinguinal lymphadenectomy; none died of cancer. Nine patients with stage II and 9 with stage III disease underwent partial or total penectomy and immediate ilioinguinal lymphadenectomy, and 5-year survival was 100 and 75%, respectively. Of 20 patients with clinical stage II disease who did not undergo immediate ilioinguinal lymphadenectomy 18 had metastasis to the groin. Of these 18 patients 12 underwent delayed ilioinguinal lymphadenectomy but only 1 survived more than 5 years. We evaluated the possible significance of the degree of histological differentiation of the primary tumor to the course of the disease. Of the 23 cases of carcinoma in situ or well differentiated disease only 1 became metastatic, while of the 35 cases of moderately to poorly differentiated disease 31 metastasized to the groin. Vascular invasion of cancer cells in the primary tumor was another indicator for poor prognosis.

Aberrant expression of MUC5AC and MUC6 gastric mucin genes in colorectal polyps

Altered mucin glycosylation and the de novo appearance of gastric mucin antigens have been described in colonic adenomas. The purpose of our study was to determine if expression of the gastric mucin genes MUC5AC and MUC6 occurs in colorectal adenomas and whether this correlates with histopathologic criteria of malignant potential. Immunohistochemical staining using antibodies against MUC5AC and MUC6 tandem repeat synthetic peptides was performed on specimens of normal colon mucosa (n = 26), hyperplastic polyps (n = 9) and adenomatous polyps (n = 111). Mucin mRNA levels were determined using RNase protection assays using riboprobes corresponding to unique non‐repetitive sequences. MUC5AC and MUC6 staining were rarely detected and of low intensity in normal colon and hyperplastic polyps. The number of immunoreactive polyps and intensity of MUC5AC and MUC6 staining were greatest in larger adenomas of moderate villous histology and dysplasia. MUC5AC and MUC6 staining tended to decrease in highly villous polyps with severe dysplasia. Increased MUC5AC mRNA levels were found in 26/45 of adenomas tested compared with 0/9 normal colon specimens. MUC6 mRNA levels were found in 20/45 of adenomas compared with 1/9 normal colon specimens. MUC5AC and MUC6 mRNA were present more frequently and at higher levels in polyps with intermediate stages of size, villous histology and dysplasia. We conclude that aberrant expression of MUC5AC and MUC6 mucin genes is likely responsible for an expanded repertoire of mucin antigen expression in colorectal neoplasia. Int. J. Cancer 80:210–218, 1999. Published 1999 Wiley‐Liss, Inc.

Intestinal ganglioneuromatosis: Mucosal and transmural types A clinicopathologic and immunohistochemical study of six cases

Six cases of intestinal ganglioneuromatosis (GN) included in this study reveal the occurrence of two morphologic patterns. Transmural GN was characterized by neural hyperplasia in all layers of the bowel wall with predominant involvement of the myenteric plexus. It was found in three patients affected by multiple endocrine neoplasia IIb. Mucosal GN, having predominant involvement of the mucosa without concomitant hyperplasia of the myenteric plexus, was associated with von Recklinghausens disease, adenocarcinoma of the colon, and multiple adenomas with megacolon in one case each. Clinicopathologic correlations and review of the literature suggest that mucosal GN might represent a distinct entity with a lower morbidity rate than the transmural variant. Immunohistochemical stains reveal considerable heterogeneity. S-100 protein, neuron-specific enolase, and synapto-physin immunostaining followed the distribution of the nervous hyperplasia in the different intestinal layers as identified morphologically and allowed precise determination of the proliferating cells. Increased reactivity for vasoactive intestinal polypeptide, opioid peptides leu-enkephalin and met-enkephalin, and substance P was present in all cases with transmural involvement; mucosal GN showed normal reactivity for opioid peptides and focal increased staining for substance P (one case) and vasoactive intestinal polypeptide (two cases) in the lamina propria. Mild increased immunoreactivity for tyrosine hydroxylase was present in the myenteric plexus of four out of four cases. Histochemical determination of acetylcholinesterase, performed in one case of transmural type, demonstrated hyperplasia of parasympathetic fibers and neurons. Electron microscopic study of another case suggested the presence of several neurotransmitters. These results indicate that the physiopathology of GN is related to a complex hyperplasia of several peptidergic, cholinergic, and probably adrenergic nerve fibers instead of a selective overgrowth of one type of nerve fiber.

Subcellular immunolocalization of protein kinase CK2 in normal and carcinoma cells.

CK2 is a messenger-independent protein serine/threonine kinase that has been implicated in cell growth and proliferation. Our recent analysis of squamous cell carcinomas of the head and neck (SCCHN) revealed a significant elevation in CK2 activity in these tumor cells relative to normal mucosa of the upper aerodigestive tract and suggested a correlation with aggressive tumor behavior and poor clinical outcome. In order to further define the distribution of CK2 in these tissues, we have examined the immunohistochemical staining pattern of surgical specimens of both SCCHN tumors and normal upper aerodigestive tract mucosa using a monoclonal antibody directed against the catalytic subunit CK2-alpha of the kinase, and have compared these data with the subcellular distribution of CK2 activity in these same tissues. These measurements showed that CK2 is predominantly localized to the nuclei of the tumor cells, which agreed closely with the immunohistochemical staining pattern of CK2-alpha in tumor cells. The chiefly nuclear distribution of CK2-alpha immunostaining found consistently in SCCHN tumor cells and tumor-infiltrating lymphocytes contrasted with a relatively more predominant cytosolic staining pattern exhibited by various cellular constituents of normal oropharyngeal mucosa. The immunostaining pattern of CK2-alpha revealed that staining was observed in the cells stained for the proliferation-marker Ki-67; however, strong distinct immunostaining for CK2-alpha was also observed in large numbers of other cells in these same tumors, suggesting that CK2 elevation in these tumors is not a reflection of proliferative activity alone, but may also relate to the pathobiological behavior of the tumor.

G1 checkpoint protein and p53 abnormalities occur in most invasive transitional cell carcinomas of the urinary bladder.

SummaryThe G1 cell cycle checkpoint regulates entry into S phase for normal cells. Components of the G1 checkpoint, including retinoblastoma (Rb) protein, cyclin D1 and p16INK4a, are commonly altered in human malignancies, abrogating cell cycle control. Using immunohistochemistry, we examined 79 invasive transitional cell carcinomas of the urinary bladder treated by cystectomy, for loss of Rb or p16INK4a protein and for cyclin D1 overexpression. As p53 is also involved in cell cycle control, its expression was studied as well. Rb protein loss occurred in 23/79 cases (29%); it was inversely correlated with loss of p16INK4a, which occurred in 15/79 cases (19%). One biphenotypic case, with Rb+p16– and Rb-p16+ areas, was identified as well. Cyclin D1 was overexpressed in 21/79 carcinomas (27%), all of which retained Rb protein. Fifty of 79 tumours (63%) showed aberrant accumulation of p53 protein; p53 staining did not correlate with Rb, p16INK4a, or cyclin D1 status. Overall, 70% of bladder carcinomas showed abnormalities in one or more of the intrinsic proteins of the G1 checkpoint (Rb, p16INK4a and cyclin D1). Only 15% of all bladder carcinomas (12/79) showed a normal phenotype for all four proteins. In a multivariate survival analysis, cyclin D1 overexpression was linked to less aggressive disease and relatively favourable outcome. In our series, Rb, p16INK4a and p53 status did not reach statistical significance as prognostic factors. In conclusion, G1 restriction point defects can be identified in the majority of bladder carcinomas. Our findings support the hypothesis that cyclin D1 and p16INK4a can cooperate to dysregulate the cell cycle, but that loss of Rb protein abolishes the G1 checkpoint completely, removing any selective advantage for cells that alter additional cell cycle proteins.

Morphine-Induced Epidermal Growth Factor Pathway Activation in Non-Small Cell Lung Cancer

BACKGROUND: Epidermal growth factor receptor (EGFR) is coactivated by the &mgr;-opioid receptor (MOR), expressed on non–small cell lung cancer (NSCLC) cells and human lung cancer. We hypothesized that clinically used opioid analgesics that are MOR agonists coactivate EGFR, resulting in growth- and survival-promoting signaling. METHODS: We used H2009, a human adenocarcinoma NSCLC cell line, with constitutive EGFR phosphorylation, which showed increased expression of MOR and the &dgr;-opioid receptor by reverse transcriptase polymerase chain reaction. We used Western immunoblotting, magnetic bead–based Bio-Plex cytokine assay, immunofluorescent staining, BrdU incorporation enzyme-linked immunosorbent assay, and BioCoat™ Matrigel™ invasion assay to examine cell signaling, cytokine expression, colocalization of MOR and EGFR in human lung cancer, and cell proliferation and invasion, respectively. RESULTS: Similar to epidermal growth factor (EGF), morphine stimulated phosphorylation of EGFR, Akt/protein kinase B (Akt), and mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) signaling in H2009 cells. Opioid receptor (OR) antagonist, naloxone, EGFR tyrosine kinase inhibitor, erlotinib, and silencing of MOR and &dgr;-opioid receptor abrogated morphine- and EGF-induced phosphorylation of signaling, suggestive of OR-mediated coactivation of EGFR. H2009 cells secreted significantly higher levels of cytokines compared with control Beas2B epithelial cells. H2009-conditioned medium stimulated MOR expression in Beas2B cells, suggesting that cytokines secreted by H2009 may be associated with increased OR expression in H2009. We observed colocalization of EGFR and MOR, in human NSCLC tissue. Functionally, morphine- and EGF-induced proliferation and invasion of H2009 cells was ameliorated by naloxone as well as erlotinib. CONCLUSION: Morphine-induced phosphorylation of EGFR occurs via ORs, leading to downstream MAPK/ERK, Akt phosphorylation, cell proliferation, and increased invasion. Notably, ORs are also associated with EGF-induced phosphorylation of EGFR. Increased coexpression of MOR and EGFR in human lung cancer suggests that morphine may have a growth-promoting effect in lung cancer.

Membrane-Bound (MUC1) and Secretory (MUC2, MUC3, and MUC4) Mucin Gene Expression in Human Lung Cancer

Abnormalities of mucin-type glycoproteins have been described in lung cancers, but their molecular basis is unknown. In this study, mucin-core-peptide-specific antibodies and cDNA probes were used to determine the relative expression of mucin genes corresponding to one membrane-bound mucin (MUC1), two intestinal mucins (MUC2 and MUC3), and one tracheobronchial mucin (MUC4) in normal (nonneoplastic) lung, and in lung neoplasms. Normal lung tissues exhibited a distinct pattern of mucin gene expression, with high levels of MUC1 and MUC4 mRNA and low to absent levels of MUC2 and MUC3 mucin immunoreactivity and mRNA. In contrast, lung adenocarcinomas, especially well-differentiated cancers, exhibited increased MUC1, MUC3, and MUC4 mRNA levels. Lung squamous-cell, adenosquamous, and large-cell carcinomas were characterized by increased levels of MUC4 mucin only. We conclude that the expression of one membrane-bound and several secretory-type mucins is independently regulated and markedly altered in lung neoplasms. The frequent occurrence of increased MUC4 transcripts in a variety of non-small-cell lung cancers indicates the potential importance of this type of mucin in lung cancer biology.