Integrin α3ß1-CD151 complex regulates dimerization of ErbB2 via RhoA.

Integrin α3ß1 regulates adhesive interactions of cells with laminins and have a critical role in adhesion-dependent cellular responses. Here, we examined the role of α3ß1-integrin in ErbB2-dependent proliferation of breast cancer cells in three-dimensional laminin-rich extracellular matrix (3D lr-ECM). Depletion of α3ß1 in ErbB2-overexpressing breast cancer cells suppressed growth and restore cell polarity in 3D lr-ECM. The phenotype of α3ß1-depleted cells was reproduced upon depletion of tetraspanin CD151 and mirrored that of the cells treated with Herceptin, an established ErbB2 antagonist. Breast cancer cells expressing the α3ß1-CD151 complex have higher steady-state phosphorylation of ErbB2 and show enhanced dimerization of the protein when compared with α3ß1-/CD151-depleted cells. Furthermore, Herceptin-dependent dephosphorylation of ErbB2 was only observed in α3ß1-CD151-expressing cells. Importantly, the inhibitory activity of Herceptin was more pronounced when cells expressed both α3ß1 and CD151. We also found that the level of active RhoA was increased in α3ß1- and CD151-depleted cells and that Rho controls dimerization of ErbB2. Expression of α3ß1 alone did not have significant prognostic value in patients with invasive ductal carcinoma of the breast. However, expression of α3ß1 in combination with CD151 represented a more stringent indicator of poor survival than CD151 alone. Taken together, these results demonstrate that the α3ß1-CD151 complex has a critical regulatory role in ErbB2-dependent signalling and thereby may be involved in breast cancer progression.

Loss of CD151/Tspan24 from the complex with integrin α3ß1 in invasive front of the tumour is a negative predictor of disease-free survival in oral squamous cell carcinoma.

OBJECTIVES: The study aimed to assess the role of CD151-integrin α3ß1 (INGA3) complex as a potential prognostic indicator in OSCC and to examine whether mapping of its expression in the invasive front separately from that in the rest of the tumour would have an impact on the predictive value of the results. CD151/INGA3 profiles were compared with that of EGFR. MATERIALS AND METHODS: Protein distributions were analysed either in the whole tumour (W) or separately, (i) the main tumour mass (TU) and (ii) the invasive front (IF) in 83 OSCC samples using immunohistochemistry. RESULTS AND CONCLUSION: There was no statistical association between any of the proteins scored in W and clinicopathologic features or patient survival. When examined separately, significant associations were shown for (i) CD151 and EGFR in TU (p=0.036) and (ii) tumour grade and EGFR in both TU (p=0.045) and IF (p=0.030). INGA3 was present predominantly in the tumour-host interface, significantly stronger in IF than TU (p=0.021). An association with 5-year disease-free survival was close to significant for INGA3 (TU and IF) (p=0.050) but not the CD151/INGA3 complex. Expression of CD151/INGA3 at the IF might reflect tumour behaviour pertinent to patient outcome.

Coculture of embryonic stem cells with pulmonary mesenchyme: a microenvironment that promotes differentiation of pulmonary epithelium.

Coculture of stem/progenitor cells with mature cells or tissues can drive their differentiation toward required lineages. Thus, we hypothesized that coculture of murine embryonic stem (ES) cells with embryonic mesenchyme from distal lung promotes the differentiation of pneumocytes. Murine ES cells were differentiated to embryoid bodies (EBs) and cultured for 5 or 12 days with pulmonary mesenchyme from embryonic day 11.5 or 13.5 murine embryos, in direct contact or separated by a membrane. Controls included EBs cultured alone or with embryonic gut mesenchyme. Histology revealed epithelium-lined channels in directly cocultured EBs, whereas EBs grown alone showed little structural organization. The lining cells expressed cytokeratin and thyroid transcription factor 1, an early developmental marker in pulmonary epithelium. Differentiation of type II pneumocytes specifically was demonstrated by the presence of surfactant protein C (SP-C) in some of the epithelial cells. None of these markers was seen in EBs cultured alone or with embryonic gut mesenchyme. Indirect coculture of EBs with lung mesenchyme resulted in a 14-fold increase in SP-C gene expression. Thus, provision of an appropriate microenvironment, in the form of pulmonary mesenchyme, appears to promote the differentiation of ES cells toward lung epithelium. Our findings may have applications in regenerative medicine strategies and the engineering of lung tissue.

Pantoprazole in severe acid-peptic disease: the effectiveness and safety of 5 years' continuous treatment.

OBJECTIVE: This is our final report on the clinical effectiveness and safety of long-term pantoprazole in patients with severe peptic ulcer or reflux disease during continuous treatment for up to 5 years. METHODS: Patients (n= 150) with peptic ulcer or reflux erosive oesophagitis running an aggressive course or with complications, and refractory to H2-receptor antagonists, were entered into this 5-year programme. Assessment was by serial endoscopy, clinical examination, serum gastrin estimation, gastric mucosal histology and mucosal endocrine cell quantification. RESULTS: Healing results were presented earlier. The estimated rates of remission on maintenance treatment with pantoprazole (n = 115) were 82% at 1 year, 75% at 2 years, 72% at 3 years, 70% at 4 years and 68% at 5 years. Helicobacter pylori infection appeared not to influence the outcome in reflux patients, with roughly two-thirds continuing in remission irrespective of infection. Only four patients had adverse events considered to be definitely related to pantoprazole. Median gastrin levels rose by 1.5-2-fold and were higher in those with H. pylori infection; 13 patients had levels >500 ng/L on at least one occasion, but these high levels were not sustained. Histological changes were more marked in patients infected with H. pylori: chronic gastritis decreased in the antrum and increased in the corpus, which also showed atrophic changes. The total number of endocrine cells in the antrum showed little variation over 60 months but fell by around one-third in the corpus. CONCLUSION: Long-term treatment with pantoprazole is effective and safe.

Pantoprazole therapy in the long-term management of severe acid peptic disease: clinical efficacy, safety, serum gastrin, gastric histology, and endocrine cell studies.

OBJECTIVE: Pantoprazole is the third proton pump inhibitor to become available. When this study was started, there were few data on its long-term use. Our aim was to investigate this aspect and, because powerful inhibitors of acid secretion can cause hypergastrinemia and, in experimental animals, enterochromaffin-like cell hyperplasia, we also monitored serum gastrin and endocrine cell histology. METHODS: One hundred fifty patients refractory to H2-receptor antagonists, running an aggressive course or with complications, were entered into a 5-yr treatment program. We performed serial endoscopy, checked for adverse events, and laboratory values. We also monitored serum gastrin, gastric endocrine cell histology, and antral and corpus gastritis. RESULTS: This report presents results from up to 3 yr of treatment. Cumulative healing on 40-80 mg of pantoprazole was 82% at 4 wk and 92% by 12 wk. Most patients became asymptomatic within 4 wk. Remission on maintenance treatment with 40 mg (n = 111) was 85% at 12 months and 78% at 24 months. Treatment was safe; only four patients had adverse events definitely related to pantoprazole. Elevations in gastrin were modest and there were no significant changes in gastric endocrine cells. The number of enterochromaffin-like cells tended to decrease. CONCLUSION: Pantoprazole is effective, safe, and does not seem to be associated with large increases in serum gastrin or alterations in gastric endocrine cells.

Up-regulation of inducible nitric oxide synthase in fibroblasts parallels the onset and progression of fibrosis in an experimental model of post-transplant obliterative airway disease.

The main cause of mortality following lung transplantation is chronic rejection, manifesting morphologically as obliterative bronchiolitis (OB). It has been suggested that damage to the respiratory epithelium initiates proliferation of mesenchymal cells, leading to dense collagenous scarring in small airways. Inducible nitric oxide synthase (iNOS) is strongly expressed in the damaged epithelium in human OB, along with high levels of peroxynitrite, suggesting that endogenous NO mediates the epithelial destruction. To examine further the role of iNOS in this process, heterotopic airway implants were studied in rats, an acknowledged disease model. Specimens of iso- or allografted trachea, collected 3-60 days after implantation, were processed for histology and immunocytochemistry for iNOS and, as a marker of peroxynitrite formation, nitrotyrosine. In both iso- and allografts at the earliest stage (day 3), ischaemia was associated with severe epithelial damage or loss. These changes progressed until day 7 and were accompanied by strong expression of iNOS and nitrotyrosine in epithelial cells. In isografts, epithelial recovery was seen, with abundant iNOS immunoreactivity but little nitrotyrosine. In contrast, the epithelium in allografts did not regenerate and progressive inflammation and fibroproliferation occurred until complete obliteration of the tracheal lumen at day 60. The fibroproliferation was associated with changes in morphology of fibroblasts that were accompanied by alterations in their iNOS expression. iNOS immunoreactivity was dense in the plump fibroblasts of early lesions, in some cases as early as post-operative day 5, but very weak in elongated fibroblasts in totally occluded grafts. The intensity of immunoreactivity for nitrotyrosine corresponded to that of iNOS. These results indicate a dual role for NO in the airway obliteration that follows transplantation, through destruction of epithelium and stimulation of fibroblast activity.

Idiopathic constipation is not associated with increased NCAM expression on intestinal muscle.

Our previous study of neural cell adhesion molecule (NCAM) in childhood Hirschsprung's disease demonstrated increased expression on intestinal muscle, especially muscularis mucosae, in aganglionic bowel. The present study was undertaken to test whether this increased NCAM expression is a feature of congenital aganglionosis rather than being a nonspecific feature of constipation. We studied specimens from six patients (20-60 years old; five women and one man) operated on for idiopathic long-standing constipation, using immunocytochemistry for NCAM and protein gene product 9.5 (PGP 9.5). Results showed that in adult constipated bowel the pattern of NCAM expression is similar to that seen in controls. There was no expression of NCAM on muscle in any of the specimens studied. Thus, it seems likely that increased NCAM expression in gastrointestinal smooth muscle in congenital aganglionosis is a result of the abnormal innervation rather than any symptomatic or clinical feature.

Neural cell adhesion molecule (NCAM) expression in nerves and muscle of developing human large bowel.

Most studies of neural cell adhesion molecule (NCAM) in human musculature are devoted to either developing or adult skeletal and cardiac muscle. The aim of this study was to determine the pattern of NCAM expression in the intestinal musculature of the developing human large bowel. In specimens of large bowel from foetuses (gestational age 8-20 weeks), we examined the immunohistochemical localisation of NCAM in parallel to those of alpha-smooth muscle actin and desmin. Within the developing neural complex, NCAM was expressed at all stages investigated. In intestinal muscle at 8 weeks, immunoreactivity for all antisera was restricted to the muscularis propria. The differentiating muscularis mucosae was demonstrated first at 15 weeks by immunostaining for alpha-smooth muscle actin, and this expression was followed by that of NCAM and desmin at 17 and 19 weeks, respectively. At 20 weeks, NCAM immunoreactivity in the external muscle was intense at the inner border of the circular muscle, with its concentration decreasing towards the outer margin of the muscular wall, whereas alpha-smooth muscle actin and desmin were uniformly distributed in all muscle layers. NCAM is expressed by nerves and muscle of developing human large intestine. Its appearance follows a predetermined pattern, which implies its relevance to the differentiation of intestinal muscle layers.

Increased expression of muscular neural cell adhesion molecule in congenital aganglionosis.

BACKGROUND: Neural cell adhesion molecule (NCAM) is down regulated during morphogenesis and innervation of cardiac and skeletal muscle. In mature muscle, its reexpression over the entire sarcolemma occurs in response to denervation or paralysis of muscle and in some myopathies. No information is available regarding NCAM expression in human enteric muscle either in health or in disease. Our aim was to test whether NCAM is present in nerves and muscle of normal infant bowel and to determine how its expression is altered in congenital aganglionosis. METHODS: Using immunocytochemistry for light microscopy, we compared the pattern of distribution of NCAM in congenitally aganglionic colon with that in colon from age-matched controls. RESULTS: In normal colon, NCAM immunoreactivity was seen in ganglion cells and nerve fibers throughout the gut wall and, more weakly, on the inner border of the circular muscle. In aganglionic bowel, there was a marked increase in NCAM expression in muscle, particularly that of the muscularis mucosac and characteristic hypertrophied nerve bundles of the intermuscular zone and submucosa displayed immunoreactivity for NCAM. CONCLUSIONS: Abnormal expression of NCAM is, thus, a feature of congenital aganglionosis and is likely to be associated with neuromuscular dysfunction within the affected colon.

Immunocytochemistry for neuronal markers shows deficiencies in conventional histology in the treatment of Hirschsprung's disease.

Despite technically satisfactory operations, at least 20% of children with Hirschsprung's disease have an unsatisfactory postoperative result. A possible explanation for their symptoms is the retention of ganglionic intestine which has demonstrable abnormalities of the enteric nervous system. The distribution of intestinal neural proteins and peptides in resected colons from patients with Hirschsprung's disease (n = 10) was compared with that in normal controls (n = 5). Immunocytochemistry was performed using antisera against general markers of the enteric nervous system (PGP 9.5, NSE, NFILs, and S-100 protein) and colonic neuropeptides (VIP, GAL, SP, NPY, CGRP, and Met-ENK). The distribution and density of peptide-containing nerve fibers varied greatly from one patient to another and no consistent pattern of neural disturbances could be discerned in aganglionic colon. At the proximal limit of resection, abnormalities of enteric innervation were detected in 8 of 10 studied specimens. Although ganglion cells staining positively for general neuronal markers were present in all cases, normal populations of neural cell bodies immunoreactive for neuropeptides could be found in only 2 specimens. Enlarged submucosal nerve trunks found in the most proximal area of most specimens, displayed immunoreactivity for general nerve markers and VIP, GAL, NPY, and CGRP. The widely practised conventional histopathological assessment of the proximal limit of colonic neural abnormalities may be inadequate.