Epithelial-Stromal Interface in Normal and Neoplastic Human Bladder Epithelium

The ultrastructure of the epithelial-stromal interface of the human urinary bladder was studied in biopsy specimens that included 7 normal controls, 1 inverted papilloma, 18 noninvasive papillary carcinomas, and 19 invasive transitional cell carcinomas. In the invasive foci of the transitional cell carcinomas, the underlying basal lamina was attenuated or absent and the number of hemidesmosomes was decreased. These neoplastic cells displayed notably increased numbers of lysosomes, some of which appeared to be in the process of exocytosis. Increased numbers of cytoplasmic filaments adjacent to the plasma membrane at the invading pole of these cells were also observed. Tight junctions and junctional complexes were noticed adjacent to the tumor-stromal interface. None of the aforementioned features was observed in normal transitional epithelium, in inverted papilloma, in noninvasive papillary carcinomas, or in the noninvasive portions of invasive transitional cell carcinomas.

Alterations of the epithelial-stromal interface deserve additional studies for they may constitute important parameters in the evaluation of actual or potential invasiveness in the various types of carcinoma of the bladder.     

Epithelial-Stromal Interface in Normal and Neoplastic Human Bladder Epithelium

The ultrastructure of the epithelial-stromal interface of the human urinary bladder was studied in biopsy specimens that included 7 normal controls, 1 inverted papilloma, 18 noninvasive papillary carcinomas, and 19 invasive transitional cell carcinomas. In the invasive foci of the transitional cell carcinomas, the underlying basal lamina was attenuated or absent and the number of hemidesmosomes was decreased. These neoplastic cells displayed notably increased numbers of lysosomes, some of which appeared to be in the process of exocytosis. Increased numbers of cytoplasmic filaments adjacent to the plasma membrane at the invading pole of these cells were also observed. Tight junctions and junctional complexes were noticed adjacent to the tumor-stromal interface. None of the aforementioned features was observed in normal transitional epithelium, in inverted papilloma, in noninvasive papillary carcinomas, or in the noninvasive portions of invasive transitional cell carcinomas.

Alterations of the epithelial-stromal interface deserve additional studies for they may constitute important parameters in the evaluation of actual or potential invasiveness in the various types of carcinoma of the bladder.     

Prevalence of six types of human papillomavirus in inverted papilloma and papillary transitional cell carcinoma of the bladder: an evaluation by polymerase chain reaction.

AIMS: To study the prevalence of high risk oncogenic human papillomaviruses (HPV) in inverted papilloma and papillary transitional cell carcinoma of the bladder. METHODS: Ten cases of inverted papilloma and 20 cases of papillary transitional cell carcinoma of the bladder from Chinese patients in Hong Kong were examined for the presence of HPV type 6, 11, 16, 18, 31, and 33 genomes using the polymerase chain reaction and HPV type specific primer probe combinations on paraffin wax embedded biopsy specimens. RESULTS: Of the 10 cases of inverted papilloma, cases 1 and 6 showed the presence of HPV types 16 and 18, respectively. Six of the 20 papillary transitional cell carcinomas were positive for HPV type 18. The other HPV types were not detected. CONCLUSIONS: HPV type 18 was found in 60% and 30% of cases of inverted papilloma and papillary transitional cell carcinoma of the bladder, respectively. These tumours were rarely associated with HPV types 6, 11, 16, 31, and 33. The role of HPV type 18 in oncogenesis of inverted papilloma and transitional cell carcinoma of the bladder requires further studies.     

Nitric oxide synthase immunoreactivity in human bladder carcinoma.

AIMS: To study the expression of the endothelial and inducible isoforms of nitric oxide synthase (eNOS and iNOS, respectively) in human bladder carcinoma and schistosomal bladder disease, and to compare it with normal adult and fetal urothelium. Nitric oxide is thought to play a complex role in human carcinogenesis, but has only recently been investigated in bladder cancer. METHODS: Immunohistochemistry was performed on paraffin wax embedded sections of 33 human bladder carcinomas and five bladder carcinoma cell lines; in addition, seven schistosomal bladder cases and normal and fetal urothelium were investigated. In the cell lines enzymatic activity was examined by the NADPH diaphorase reaction. RESULTS: Immunoreactivity for eNOS was present in most cells of all 31 cases examined. Immunoreactivity for iNOS was less abundant and was seen in 23 of 25 cases. Similar findings were noted in schistosomal bladder cancer. In the normal bladder mucosa, eNOS immunoreactivity was found only in the superficial cell layer and iNOS was not expressed, whereas in the fetal urothelium immunoreactivity for both isoforms was seen in all cell layers. Enzymatic activity and immunoreactivity for eNOS and iNOS were evident in the five bladder carcinoma cell lines. CONCLUSIONS: It is possible that NOS plays a role in the differentiation of the transitional epithelium in fetal life, has a biological function in the adult bladder mucosa, and is involved in bladder carcinogenesis. eNOS and iNOS immunoreactivity do not differ in schistosomal and non-schistosomal bladder carcinoma, but resemble the pattern of expression typical of fetal urothelium.     

Papillomavirus and c-myc antigen expression in normal and neoplastic cervical epithelium.

Cervical punch biopsy specimens or brushings were collected from 33 patients with cervical human papilloma virus (HPV) infection, cervical intraepithelial neoplasia (CIN), or invasive cervical carcinoma, and from eight control patients with recent normal cervical cytology. Prostatic chippings obtained from six men with benign prostatic hypertrophy were used as further controls. Biopsy specimens and brushings were assayed by flow cytometry for c-myc oncogene antigen and papillomavirus antigen expression and rate of cell division (by measuring DNA content). Results obtained from analysis of specimens and brushings were similar in terms of c-myc antigen and total DNA content, but when the percentages of nuclei from biopsy and brush specimens staining positively with antibody to papilloma viral antigens were compared, brush specimens gave consistently higher percentages than biopsy specimens. More specimens from normal epithelium were c-myc antigen positive (five of eight, (63%) than specimens from CIN II or III (two of 10, 20%), or invasive carcinoma (0%). No association was found between c-myc antigen expression and cell division. HPV antigen positive specimens were found to contain more dividing cells than negative specimens.     

Scanning electron microscopy of normal, neoplastic and inflamed human bladder

Scanning electron microscopy (SEM) was used to compare the topographic fine structure of urothelium from normal, neoplastic and inflamed human bladders. The three groups of patients show different patterns. The normal bladder lining is characterized by regularly arranged large superficial cells with ridged surfaces. By contrast, the surface cells of a transitional cell carcinoma are rounded up and covered with microvilli. In some patients with cystitis or post inflammatory hyperplasia SEM appearances intermediate between normal and neoplastic patterns are encountered. However, except in extremely severe cystitis it is possible on SEM to differentiate between inflamed and neoplastic urothelium. Surface microvilli provide a useful malignant marker for transitional cell carcinoma. However, severe inflammation of the bladder, when diagnosed on cystoscopic examination, can and must be excluded by light microscopy before this marker is considered diagnostic for neoplasia.     

Observer variability in histopathological reporting of transitional cell carcinoma and epithelial dysplasia in bladders

Sections from 90 urinary bladder biopsy specimens were examined by 11 consultant histopathologists with varying experience to determine the appropriateness of existing pathology terminology. Analysis with kappa statistics showed fair to good agreement in the grading and staging of transitional cell carcinoma. There was also reasonable agreement in the diagnosis of high grade dysplasia in random biopsy specimens from the urothelium adjacent to the neoplasm, but very poor agreement for lesser degrees of dysplasia. It is concluded that the present classification of bladder carcinomata is reliable and that pathologists can determine stage with a high degree of reproducibility and grade with a fair degree of reproducibility.     

Renal cell carcinomas and pancreatic adenocarcinomas produce nidogen in vitro and in vivo

The production of nidogen by four renal cell carcinoma (RCC) and three pancreatic adenocarcinoma (PAc) cell lines has been studied in cell culture and in xenografted tumours in nude mice. In RCC cells, immunoreactivity for nidogen was seen only after exposure to monensin to induce cytoplasmic accumulation of secretory proteins. In PAc cells, immunoreaction was also detectable in control cells. Immunoblotting of control and monensin-exposed cells and immunoprecipitation of culture media of radioactively labelled cells demonstrated the production of nidogen polypeptide of M_r ca. 150000 by six of the seven cell lines. Basement membranes (BMs) and stroma of the xenografted tumours derived from these six cell lines demonstrated immunoreactivity for both human and mouse nidogen, as revealed with species-specific antibodies. The ability of the cells to produce nidogen in vitro and deposit in vivo was positively correlated with high histological grade of the xenografted tumours, although the small number of cell lines studied calls for further studies to confirm this. The distribution of nidogen in human RCC and PAc specimens was also studied by immunohistochemistry. There was strong immunoreactivity for nidogen in tumour stroma, BM of carcinoma cell nests, and endothelial basal lamina, but no conclusions could be drawn regarding histological grade and immunostaining patterns, because stromal production could not be ruled out. The results show that nidogen is produced by human carcinoma cells both in vitro and in vivo. Copyright © 1999 John Wiley & Sons, Ltd.     

Expression of interleukin-8 correlates with vascularity in human gastric carcinomas.

Interleukin (IL)-8 is a multifunctional cytokine that can stimulate the division of endothelial cells. We examined the expression of IL-8 mRNA using Northern blot analysis and in situ mRNA hybridization (ISH) and protein production using enzyme-linked immunosorbent assay and immunohistochemistry in 8 human gastric carcinoma cell lines and 39 gastric carcinomas and corresponding normal mucosa (34 surgical specimens and 5 biopsy specimens). Of the 8 human gastric carcinoma cell lines, 6 expressed 1.8-kb IL-8 mRNA and secreted various levels of IL-8 protein. The expression of IL-8 by TMK-1 cells was induced by exposure to IL-1 alpha, epidermal growth factor, and transforming growth factor-alpha, shown previously to be autocrine growth stimulators for human gastric carcinoma cells. In tumor tissues, most of the tumors (28 of 34 surgical specimens and 4 of 5 biopsy specimens) expressed IL-8 at higher levels than the corresponding normal mucosa. ISH and immunohistochemical analyses revealed that IL-8 mRNA and protein were localized in the cytoplasm of tumor cells. The number of blood vessels in the gastric carcinomas was determined by using antibodies against CD34. The level of IL-8 mRNA in the neoplasms strongly correlated with vascularization (Spearman correlation, r = 0.812; P = 0.001). The data suggest that IL-8 produced by tumor cells may regulate neovascularization and, hence, the growth and spread of human gastric carcinoma.     

In vitro studies of epithelium-associated crystallization caused by uropathogens during urinary calculi development

Infectious urinary stones account for about 10% of all urinary stones. In 50% of cases urolithiasis is a recurrent illness, which can lead to the loss of a kidney if not properly treated. One of the reasons for recurrence of the disease may be the ability of bacteria to invade urothelial cells, persist in the host cells and serve as potential reservoirs for infection. Various uropathogens are associated with the formation of bacteria-induced urinary stones but Proteus mirabilis is the most commonly isolated (70%). An in vitro model was used in this study to analyze intracellular growth and crystallization in the presence of P. mirabilis, Klebsiella pneumoniae and Escherichia coli. Human ureter (Hu 609) and bladder (HCV 29) epithelial cell lines were infected with bacteria and incubated (3–72 h) in the presence of synthetic urine and amikacin to prevent extracellular bacterial growth. During the incubation the number of bacteria (CFU/ml) inside epithelial cells and the intensity of crystallization were established. Crystallization was determined as an amount of a calcium radioisotope. The chosen strains of uropathogens were able to invade both types of epithelial cells but the Hu 609 cells were invaded to a higher extent. However, crystallization occurred only in the presence of P. mirabilis strains which were invasive and urease-positive. The highest intensity of cell-associated crystallization was observed when the number of bacteria within the urothelium remained stable during the time of incubation. These results show that P. mirabilis has an ability to form crystals inside the host cells. Under these conditions bacteria are protected from antibiotic killing, which leads to persistent and recurrent infections. We also suspect that this phenomenon may be an important stage of kidney stones formation.     

The invasive behavior of two human nasopharyngeal carcinoma (NPC) cell lines CNE-1, CNE-2Z in vitro]

Method of co-culture of tumor cells with precultured heart fragments (PHF) in vitro was used in studying the invasive behavior of human nasopharyngeal carcinoma (NPC) cell lines CNE-land CNE-2Z respectively. This improved method was based on the gyrotory shaker organ culture technique originally established by Mareel in order to show NPC cell invasiveness in a rather identical image. Histopathological sections revealed that the tumor cells might invade into the cell layer of fibroblasts surrounding the heart tissue. This would make the heart muscle cells degenerated, atrophied and necrotic and finally displaced by the fibrotic tissue. Data also pointed out that CNE-2Z cells showed more active invasive ability than that of the CNE-1 cells in the organ culture.     

Oncogene-induced basement membrane invasiveness in human mammary epithelial cells

Expression of the intermediate filament protein vimentin, and loss of the cellular adhesion protein uvomorulin (E-cadherin) have been associated with increased invasiveness of established human breast cancer cell linesin vitro andin vivo. In the current study, we have further examined these relationships in oncogenically transformed human mammary epithelial cells. A normal human mammary epithelial strain, termed 184, was previously immortalized with benzo[a]pyrene, and two distinct sublines were derived (A1N4 and 184B5). These sublines were infected with retroviral vectors containing a single or two oncogenes of the nuclear, cytoplasmic, and plasma membrane-associated type (v-ras ^H, v-ras ^Ki, v -mos, SV40T and c -myc). All infectants have been previously shown to exhibit some aspects of phenotypic transformation. In the current study, cellular invasiveness was determinedin vitro using Matrigel, a reconstituted basement membrane extract. Lineage-specific differences were observed with respect to low constitutive invasiveness and invasive changes after infection withras, despite similarras-induced transformation of each line. Major effects on cellular invasiveness were observed after infection of the cells with two different oncogenes (v-ras ^H + SV40T and v -ras ^H + v -mos). In contrast, the effects of single oncogenes were only modest or negligible. All oncogenic infectants demonstrated increased attachment to laminin, but altered secretion of the 72 kDa and 92 kDa gelatinases was not associated with any aspect of malignant progression. Each of the two highly invasive double oncogene transformants were vimentinpositive and uvomorulin-negative, a phenotype indicative of the epithelial-mesenchymal transition (EMT) previously associated with invasiveness of established human breast cancer cell lines. Weakly invasive untransformed mammary epithelial cells in this study were positive for both vimentin and uvomorulin, suggesting that uvomorulin may over-ride the otherwise vimentin-associated invasiveness.     

Expression of p63 in thymomas and normal thymus

The p63 gene, a member of the p53 family, is an epithelial marker expressed in embryonic ectoderm, breast myoepithelium, prostate, oral epithelium, epidermis, and urothelium. The DeltaN-p63 isoforms of p63, which are believed to behave as oncogenes, are expressed in squamous cell carcinoma, basal cell carcinoma, and transitional cell carcinoma. Only a few authors have looked for p63 expression in thymomas and normal thymus. We, therefore, thought of undergoing such a search by taking advantage of our archival material. We studied 66 cases of thymoma (1 type A, 8 type AB, 12 type B1, 19 type B2, 12 type B3, and 14 type C/thymic carcinoma) and 10 specimens of normal human thymus arranged in tissue microarrays. All thymomas (including thymic carcinomas) were positive for p63 regardless of type. Most of the epithelial cells of the normal thymus were also positive for this marker.     

Glioma invasionin vitro: regulation by matrix metalloprotease-2 and protein kinase C

A hallmark of invasive tumors is their ability to effect degradation of the surrounding extracellular matrix (ECM) by the local production of proteolytic enzymes, such as the matrix metalloproteases (MMPs). In this paper, we demonstrate that the invasion of human gliomas is mediated by a 72 kDa MMP, referred to as MMP-2, and provide further evidence that the activity of MMP-2 is regulated by protein kinase C (PKC). The invasiveness of five human glioma cell lines (A172, U87, U118, U251, U563) was assessed in anin vitro invasion assay and was found to correlate with the level of MMP-2 activity (r ² = 0.95); in contrast, the activity of this 72 kDa metalloprotease was barely detectable in non-invasive control glial cells (non-transformed human astrocytes and oligodendrocytes). Treatment with 1,10-phenanthroline, a metalloprotease inhibitor, or with a synthetic dipeptide, containing a blocking sequence (ala-phe) specific for MMPs, resulted in a > 90% reduction in glioma invasion. Furthermore, this MMP-2 activity could be inhibited by the treatment of tumor cells with calphostin C, a specific inhibitor of PKC. Glioma cell lines treated with calphostin C demonstrated a dose-dependent decrease (IC₅₀ = 30 nm) in tumor invasiveness with a concomitant reduction in the activity of the MMP-2. Conversely, treatment of non-invasive control astrocytes with a PKC activator (phorbol ester) led to a corresponding increase in their invasiveness and metalloprotease activity. These findings support the postulate that MMP-2 activity constitutes an important effector of human glioma invasion and that the regulation of this proteolytic activity can be modulated by PKC.Joon Uhm and Nora Dooley contributed equally to this work.     

Ber-EP4: new monoclonal antibody which distinguishes epithelia from mesothelial.

A new monoclonal antibody, Ber-EP4, directed against a partially formol resistant epitope on the protein moiety of two 34 kilodalton and 39 kilodalton glycopolypeptides on human epithelial cells is described. Immunostaining of a wide range of normal and neoplastic human tissues and cell lines showed that all carcinomas and all non-neoplastic epithelial cells, except hepatocytes, parietal cells, and apical cell layers in squamous epithelia, homogeneously expressed Ber-EP4 antigen. As Ber-EP4 does not detect any normal or neoplastic non-epithelial cells, this antibody might prove valuable for the differentiation of the following (i) non-epithelial tumours from undifferentiated carcinomas; (ii) hepatocytes from bile duct cells in certain liver diseases; (iii) mesothelial cells from carcinoma cells in lung biopsy specimens; and (iv) reactive mesothelial cells from carcinoma cells in smears of serous effusions.     

Towards defining roles and relationships for tenascin-C and TGFbeta-1 in the normal and neoplastic urinary bladder

Tenascin-C (TN-C) is an extracellular matrix glycoprotein expressed along epithelial/stromal boundaries during tissue remodelling events, such as those that occur during morphogenesis, wound healing, and tumour invasion. Using clinical specimens and a range of in vitro models that simulate homeostasis, wound healing, and malignant progression, this study sought to establish the patterns of TN-C expression in normal and neoplastic bladder and to determine the role of exogenous transforming growth factor beta-1 (TGFbeta-1), interleukin-4 (IL-4), basic fibroblast growth factor (bFGF), tumour necrosis factor alpha (TNFalpha), and interferon gamma (IFNgamma) in the induction of TN-C expression by bladder uro-epithelial cells. The findings indicate that normal urothelial cells may express TN-C, with both TGFbeta-1 and IL-4 able to induce expression. TN-C was not expressed in neoplastic urothelium, although both TN-C and TGFbeta-1 may be involved in tissue remodelling during papillary tumour formation and invasion. Furthermore, the urothelium of high-grade papillary tumours and carcinoma in situ specimens exhibited little TGFbeta-1 immunoreactivity, compared with the urothelium of low-grade tumours and normal specimens, suggesting an association between TGFbeta-1 expression and urothelial differentiation. A tumour invasion model, in which established bladder cancer cell lines were seeded onto a normal bladder stroma, corroborated the evidence from the clinical specimens and demonstrated that TN-C was strongly expressed around foci of stromal invasion. Thus, TN-C immunoreactivity may provide an additional tool in the assessment of early stromal invasion in bladder cancer.     

Cytokeratins in normal and malignant transitional epithelium. Maintenance of expression of urothelial differentiation features in transitional cell carcinomas and bladder carcinoma cell culture lines.

The pattern of cytokeratins expressed in normal urothelium has been compared with that of various forms of transitional cell carcinomas (TCCs; 21 cases) and cultured bladder carcinoma cell lines, using immunolocalization and gel electrophoretic techniques. In normal urothelium, all simple-epithelium-type cytokeratins (polypeptides 7, 8, 18, 19) were detected in all cell layers, whereas antibodies to cytokeratins typical for stratified epithelia reacted with certain basal cells only or, in the case of cytokeratin 13, with cells of the basal and intermediate layers. This pattern was essentially maintained in low-grade (G1, G1/2) TCCs but was remarkably modified in G2 TCCs. In G3 TCCs simple-epithelial cytokeratins were predominant whereas the amounts of component 13 were greatly reduced. Squamous metaplasia was accompanied generally by increased or new expression of some stratified-epithelial cytokeratins. The cytokeratin patterns of cell culture lines RT-112 and RT-4 resembled those of G1 and G2 TCCs, whereas cell line T-24 was comparable to G3 carcinomas. The cell line EJ showed a markedly different pattern. The results indicate that, in the cell layers of the urothelium, the synthesis of stratification-related cytokeratins such as component 13 is inversely oriented compared with that in other stratified epithelia where these proteins are suprabasally expressed, that TCCs retain certain intrinsic cytoskeletal features of urothelium, and that different TCCs can be distinguished by their cytokeratin patterns. The potential value of these observations in histopathologic and cytologic diagnoses is discussed.     

Subvisual changes in chromatin organization state are detected by karyometry in the histologically normal urothelium in patients with synchronous papillary carcinoma

This study analyzed the chromatin organization state in histologically normal urothelium in patients with synchronous papillary carcinoma using digital texture analysis. The quantitative evaluation was carried out on hematoxylin and eosin-stained sections from 17 cases of urothelial papillary carcinoma in which a simultaneous biopsy specimen featuring histologically normal urothelium was available. Five bladder biopsy specimens of histologically normal urothelium from patients with prostate pathology in whom cystoscopy revealed a normal bladder mucosa were also analyzed. Karyometry showed that the 17 cases of papillary carcinoma, morphologically classified according to the 1973 World Health Organization scheme, belonged to a continuous spectrum or trend curve spanning grade 1 to grade 3. An abnormal pattern and distribution of the nuclear chromatin was seen in the normal-looking urothelium from the 17 bladders with papillary lesions. When this population was plotted along the trend curve, it occupied an intermediate position between the normal samples and samples from grade 1 carcinoma. When the nuclei were considered individually, the changes were detected only in a subpopulation of nuclei with chromatin alteration pointing toward that seen in grade 1 cases, even though distinct from them. In conclusion, karyometry can detect an abnormal chromatin pattern and distribution in the normal-looking urothelium adjacent to papillary carcinoma. Such alterations correspond to the so-called "malignancy-associated change."     

Expression of cyclooxygenase-1 and -2 in urinary bladder carcinomas in vivo and in vitro and prostaglandin E2 synthesis in cultured bladder cancer cells

Cyclooxygenases (Coxs) are the rate-limiting enzymes catalysing the formation of prostaglandins, which are involved in various of physiological processes. Increased Cox-2 expression has been observed in several malignancies, but the exact role of Cox-2 in carcinogenesis remains unsolved. We studied the expression of both Cox-1 and Cox-2 by immunohistochemistry in 29 transitional cell carcinomas of the urinary bladder. Diffuse cytoplasmic immunosignal for Cox-2 was detected in all cancer specimens. The expression was moderate in 55% and strong in 31% of the carcinomas. The normal urothelium in the samples stained also for Cox-2, but the intensity of the immunosignal was weak in most specimens. Cox-1 was expressed in the stroma of bladder wall, whereas in the tumour cells, Cox-1 immunosignal was either absent or weak. No correlation was detected between Cox-1 or Cox-2 expression and tumour differentiation or stage of invasion. We also evaluated the mRNA expression of Cox-1 and Cox-2 and synthesis of prostaglandin E2 (PGE2) in three bladder carcinoma cell lines (RT4, 5637, and T24). All cell lines expressed high levels of Cox-2 mRNA, whereas Cox-1 mRNA expression was detected only in T24 cells. There was great variation in the basal levels of PGE2 synthesis in these cell lines. Indomethacin inhibited the synthesis of PGE2 in all three cell lines, although the level of Cox-2 mRNA tended to increase by indomethacin. These results indicate that Cox-2 is widely expressed in human bladder carcinomas and that the role of Cox-2 inhibition in bladder cancer should be further studied.