E-cadherin and catenins: molecules with versatile roles in normal and neoplastic epithelial cell biology

Expression of major histocompatibility complex (MHC) antigens was studied in the brains of 10 healthy sheep 2 months to 5 years old and 13 sheep infected with visna virus by intracerebral inoculation and killed one and 6 months post infection (p.i.). In healthy sheep there was prominent expression of class I, mainly on endothelial cells but also detected on ependyma, choroid plexus and in the leptomeninges. Class II expression was sparse. It was observed on perivascular cells, in choroid plexus, leptomeninges and on microglial cells in the white matter. No definite increase with age in the constitutive expression of class I and II was observed, confirming that we are dealing with a true constitutive expression. In visna-infected sheep a considerable induction of MHC antigens on microglia was observed, which correlated with severity of lesions and was mainly found in or adjacent to inflammatory infiltrates of the white matter. Increase in class II antigen expression was detected in all sheep but class I only in sheep with the most severe lesions 6 months p.i., an indication of a higher threshold for induction of class I than class II antigens on microglia. Few cells expressed viral antigens, indicating that direct immune-mediated destruction of infected cells plays a minor role in evolution of lesions. Since the preferential induction of MHC antigens on microglia in the white matter correlated with the lesion pattern, activated microglia may play a considerable role in the pathogenesis of lesions.     

Simultaneous loss of E-cadherin and catenins in invasive lobular breast cancer and lobular carcinoma in situ

Loss of expression of the intercellular adhesion molecule E-cadherin frequently occurs in invasive lobular breast carcinomas as a result of mutational inactivation. Expression patterns of E-cadherin and the molecules comprising the cytoplasmic complex of adherens junctions, alpha-, beta- and gamma-catenin, were studied in a series of 38 lobular breast carcinomas with known E-cadherin mutation status. The effect of loss of E-cadherin by mutational inactivation (or other mechanisms) on the expression of catenins was investigated. Complete loss of plasma membrane-associated E-cadherin expression was observed in 32 out of 38 invasive lobular carcinomas, for which in 21 cases a mutation was found in the extracellular domain of E-cadherin. In total, 15 frameshift mutations of small deletions or insertions, ranging from 1 to 41 bp, three non-sense mutations, and three splice mutations were identified. Mutations were scattered over the whole coding region and no hot spots could be detected. In all cases, simultaneous loss of E-cadherin and alpha- and beta-catenin expression was found; in 50 per cent of these cases, additional loss of gamma-catenin was observed. In six invasive lobular carcinomas, expression of both E-cadherin and catenins was retained. In none of these carcinomas was an E-cadherin mutation detected. Lobular carcinoma in situ adjacent to invasive lobular carcinoma showed simultaneous loss of E-cadherin and catenins in all the cases studied--remarkably, also, in four cases positive for E-cadherin and catenin expression in the invasive component. These results indicate that simultaneous loss of E-cadherin and alpha-, beta- and gamma-catenin may be an important step in the formation of lobular carcinoma in situ, as a precursor of invasive lobular breast cancer. Events additional to E-cadherin inactivation must be involved in the transition of lobular carcinoma in situ to invasive lobular carcinoma.     

Dominant role of E-cadherin in the progression of bladder cancer

PURPOSE: To elucidate factors with a role in the progression of bladder cancer. MATERIALS AND METHODS: One invasive (T24) and two superficial (RT4 and KK47) human bladder cancer cell lines, which express metastasis-related genes, were used. Cells were intravenously inoculated into chick embryos to evaluate metastatic potential to the liver. An orthotopic model with severe combined immunodeficiency mice was also used to investigate both histological appearance and changes in metastasis-related gene expression. Finally, gene expression patterns in a clinical setting were compared between superficial and invasive bladder cancers. RESULTS: In culture condition metastasis-related genes, including matrix metalloproteinases, urokinase-type plasminogen activator, and integrins alpha2 and alpha3 were continually expressed in T24 but only slightly or not at all in RT4 and KK47, respectively. The expression pattern of the metastasis-related genes in vitro reflected the characteristics of the original tumors. Liver metastasis in chick embryos was demonstrated not only with T24 cells, but also with RT4 cells in which enhanced expression of metastasis-related genes was induced. In the orthotopic model, histological appearances were in accordance with the characteristics of the original tumors, although enhanced gene expression was notable with RT4. Expression of E-cadherin by Western blotting was demonstrated only with RT4 under these experimental conditions. Furthermore, predominant E-cadherin mRNA expression was found in superficial and not in invasive human primary bladder cancers; expression of other genes was similar in the two groups. Dominant expression of E-cadherin in superficial tumors was confirmed by immunohistochemical analysis. CONCLUSIONS: These results implicate loss of E-cadherin expression as a critical factor in facilitating the progression of bladder cancer.     

Inflammation in high-grade carotid stenosis: a possible role for macrophages and T cells in plaque destabilization

BACKGROUND AND PURPOSE: Inflammatory mechanisms have been implicated in the pathogenesis of atherosclerosis. In this study, we investigated whether the extent of inflammatory infiltration in high-grade stenoses of the internal carotid artery (ICA) correlates to clinical features of plaque destabilization. METHODS: Endarterectomy specimens from 37 consecutive patients undergoing surgery for high-grade ICA stenosis were stained immunocytochemically for macrophages (CD68) and T cells (CD3). The staining was quantified by planimetry of immunostained areas (CD68) or counting individual cells (CD3). Clinical evidence of plaque instability was provided by the preoperative assessment of recent ischemic symptoms attributable to the stenosis and of the occurrence of cerebral microembolism in transcranial Doppler ultrasound monitoring of the ipsilateral middle cerebral artery. RESULTS: The percentage of macrophage-rich areas and number of T cells per mm2 section area were larger in recently symptomatic patients than in asymptomatic patients (macrophages: 18+/-10% versus 11+/-4%, P=0.005; T cells: 71.2+/-34.4 versus 40.5+/-31.4 mm2, P=0.005). The presence of microembolism was associated with an increase in macrophage-rich areas (P=0.011). Macrophage (19+/-10% versus 9+/-3%, P=0.0009) and T cell (71.5+/-39.0 versus 46.4+/-22 mm2, P=0.045) infiltration were more pronounced in predominantly atheromatous than in fibrous plaques, but did not correlate significantly to the presence of surface ulceration or luminal thrombosis. CONCLUSIONS: Our data suggest a role of plaque-infiltrating macrophages and T cells in the clinical destabilization of high-grade ICA stenoses. Inflammatory mechanisms may be a therapeutic target in patients with symptomatic ICA disease.     

A possible role for PKC delta in cerebellar granule cells apoptosis

Cerebellar granule cells (CGC) undergo massive DNA fragmentation, an apoptotic marker, in 8-day-old rat cerebellum. In vitro, they survive in the presence of depolarizing concentrations of KCl. Bisindolylmaleimide, a specific PKC inhibitor, blocks CGC apoptosis in vitro. Here I show that PKC delta, which has been involved in apoptosis in different cell lines, is constitutively cleaved in CGC, suggesting that its catalytic subunit is active per se. Moreover, KCl deprivation induces cyclin D1 expression and accumulation in nuclei. This process is blocked by bisindolylmaleimide. A model is proposed where, in the absence of survival signals, activated PKC delta induces cyclin D1 expression and accumulation in the nucleus, which subsequently, would lead to an aborted cell cycle and apoptosis.     

Abnormalities in functional development of the Sertoli cells in rats treated neonatally with diethylstilbestrol: a possible role for estrogens in Sertoli cell development

Diethylstilbestrol (DES) was administered neonatally (Days 2-12; 10 microg on alternate days) to rats, and developmental changes in Sertoli cell function were evaluated at 18, 25, and 35 days of age and compared to those observed in rats administered a GnRH antagonist (GnRHa; Days 2 and 5; 10 mg/kg) or a vehicle (controls). DES and GnRHa treatments resulted in similar reductions in both Sertoli cell numbers (40% for DES, 48% for GnRHa) and suppression of testicular growth at 18 and 25 days, though by 35 days the suppression was more pronounced (p < 0.001) in DES-treated animals. Plasma FSH levels were suppressed markedly at 18 and 25 days, but not at 35 days, in GnRHa-treated rats, whereas in DES-treated rats the FSH levels were suppressed significantly only at 35 days. Both treatments suppressed plasma levels of inhibin B, though this was more pronounced (p < 0.05) in DES- than in GnRHa-treated rats. In controls, Sertoli cell immunoexpression of inhibin alpha, sulfated glycoprotein-1 (SGP-1), and androgen receptor (AR) increased in intensity and changed to an adult, stage-dependent pattern by 25 days. In GnRHa-treated rats these changes were reduced in intensity but were similar to those in controls at 35 days. In DES-treated rats, the increase in intensity and stage-dependent pattern of immunoexpression of inhibin alpha, SGP-1, and AR were virtually absent at 25 days but were present by 35 days. Germ cell volume per Sertoli cell was reduced in GnRHa- and DES-treated rats compared with controls at 18 and 25 days but was significantly greater (p < 0. 001) in DES- than in GnRHa-treated rats at 35 days. The proportion of apoptotic to viable germ cells was increased (p < 0.01) in GnRHa- and DES-treated rats compared with controls at 18 and 25 days; but at 35 days, values in GnRHa-treated rats had declined to control values whereas those for DES-treated rats remained 10-fold elevated (p < 0.001). In adulthood, testis weight and daily sperm production were reduced by 43% and 44%, respectively, in GnRHa-treated rats, but spermatogenesis was grossly normal. Comparable changes were observed in approximately 25% of DES-treated rats, but the majority exhibited > 60% reduction in testis weight with many Sertoli cell-only tubules and very low daily sperm production. Taken together, these data are interpreted as providing evidence for direct modulation of Sertoli cell (maturational) development by DES.     

Anti-malignin antibody evaluation: a possible challenge for cancer management

The major problem in the management of cancer is the difficulty of an early diagnosis. Clinical signs and symptoms generally appear late in the course of the disease. The availability of a non-invasive test which detects a blood molecule closely associated with the malignant transformation of the cells could be of help in the early detection of cancer. Malignin is a 10 kDa polypeptide located in the cytoplasmic and outer membranes of all malignant cells. Anti-malignin antibodies (AMAs) are IgM immunoglobulins spontaneously produced by the host against the oncoprotein malignin when neoplastic transformation occurs; since AMAs are IgM, they can represent an "early" transformation indicator useful for the early detection of cancer. Elevated AMA serum concentrations, measured by means of TARGET@ reagent, have been demonstrated in patients with a wide spectrum of non-terminal active cancers, regardless of the anatomical site and histotype of the tumor. The AMA test showed a sensitivity and specificity of 95% on first determination and > 99% on repeated determinations, and has been reported to be a promising diagnostic tool for the early detection of cancer, as well as for monitoring of the response to treatment and possibly for screening of an asymptomatic population.     

Neurotrophin-Trk receptor interactions in neoplasia: a possible role in interstitial and perineural invasion in ductal pancreatic cancer

Autocrine and paracrine influences of growth factors play a critical role in the regulation of the growth, survival, differentiation, and invasion potential of tumor cells. These influences on the neoplastic phenotype are particularly important in those cancers in which tumor-stroma interactions constitute important components of tumor development, as exemplified by prostatic, breast, and pancreatic carcinomas. The neurotrophins and their corresponding Trk and p75(NGFR) receptor subtypes are families of growth factors and receptors that have received relatively little attention with respect to neoplasia. This review attempts to summarize their biochemical properties, their role in neuronal and non-neuronal systems, and their involvement in the development of a variety of cancers, particularly those in which perineural invasion and/or metastasis to the CNS are a part of the pathophysiological presentation. In this regard, we have focused on our studies of neurotrophin-Trk/p75(NGFR) expression and interactions in pancreatic ductal carcinoma (PDAC) and their potential role in the perineural invasive phenotype characteristic of this cancer.     

Treatment of clinical stage I testicular cancer and a possible role for new biological prognostic parameters

Three different treatment strategies for patients with stage I non-seminomatous testicular cancer are available that will all result in long-term survival in more than 98% of the patients: a "wait and see" strategy with follow-up and chemotherapy in cases of tumour progression, retroperitoneal lymphadenectomy, with or without application of systemic chemotherapy, in cases of retroperitoneal metastases (pathological stage II disease) or primary adjuvant chemotherapy following inguinal orchiectomy. Each treatment strategy is associated with specific side-effects. In several studies histological characteristics of the primary tumour, particularly the presence of vascular invasion and of embryonal carcinoma cells, have been demonstrated to be significant prognostic factors for the risk of occult retroperitoneal metastases in patients with stage I disease. In addition, new biological prognostic factors determined by flow cytometry, cytogenetic analysis or molecular-biological DNA or RNA analysis have been investigated, among which alterations of the p53 tumour-suppressor gene may represent a promising new prognostic factor. Although alterations of p53 gene expression seem to be associated with advanced tumour stage and may predict retroperitoneal metastatic disease, the independent role of these molecular genetic alterations needs to be prospectively studied. Currently a risk-adapted treatment strategy based on the histological criteria of vascular invasion and the presence of embryonal carcinoma can be used to stratify patients into a "high-" and "low-risk" group with respect to tumour progression. While primary-nerve-sparing retroperitoneal lymphadenectomy or adjuvant chemotherapy with two cycles of platinum, etoposide and bleomycin may be appropriate for patients with a high risk (above 40%) for tumour progression, a "wait-and-see" strategy can be used for "low-risk" (less than 15% risk of progression) patients. Molecular investigations of prognostic factors may be able to improve further the stratification of patients into these different risk categories.     

Care in psychiatry--caring for and supervising is possible with a "parent role"

The effect of superoxide dismutase (SOD) and selenium on the blood level of ferritin and transferrin in patients with hemoblastosis was studied. Two-month treatment with SOD and selenium had no effect on the level of ferritin but reduced the concentration of malonic dialdehyde (MDA) in the native erythrocytes in patients with chronic lymphoid leukemia practically to that in healthy individuals. In erythrocytes which formed from cells of the leukemic clone (chronic myelocytic leukemia and erythremia) treatment with SOD and selenium reduced the pathologically high level of ferritin, but at the same time increased the concentration of MDA in the erythrocytes. In erythremia in the group with a low level of ferritin SOD and selenium caused no statistically significant increase in its level in blood.     

A possible role for saliva as a diagnostic fluid in patients with chronic pain

Magnetic resonance (MR) imaging of the joints with routine pulse sequences can show the three main categories of osteochondral and chondral injuries: osteochondral fractures, osteochondritis dissecans, and chondral fractures. Detecting acute osteochondral fractures, which frequently accompany ligament tears, may modify patient treatment and ultimately may prove important in long-term prognostication. Staging osteochondritis dissecans lesions is possible with MR imaging and can be used to guide therapy, both surgical and nonsurgical. Specific treatment for chondral fractures is evolving; preoperative diagnosis using MR imaging is advantageous because these lesions often are not initially suspected, they are radiographically occult, and they clinically mimic other internal derangements, for which therapy differs. The MR imaging finding that these traumatic lesions share is the frequent presence of an abnormality in the subchondral bone. Fat-suppressed images are the key to detecting subtle areas of subchondral edema, which in turn may draw attention to a defect in the overlying articular surface.     

Association with terminal exons in pre-mRNAs: a new role for the U1 snRNP?

Psoralen cross-linking experiments in HeLa cell nuclear extracts have revealed the binding of U1 snRNA to substrates containing the SV40 late and adenovirus L3 polyadenylation signals. The sites of U1 cross-linking to the substrates map different distances upstream of the AAUAAA sequence to regions with limited complementarity to the 5' end of U1 snRNA. U1 cross-linking to the same site in the SV40 late pre-mRNA is enhanced by the addition of an upstream 3' splice site, which also enhances polyadenylation. Examination of different nuclear extracts reveals a correlation between U1 cross-linking and the coupling of splicing and polyadenylation, suggesting that the U1 snRNP participates in the coordination of these two RNA-processing events. Mutational analyses demonstrate that U1/substrate association cannot be too strong for coupling to occur and suggest that the U1 snRNP plays a similar role in recognition of internal and 3' terminal exons. Possible mechanisms for communication between the splicing and polyadenylation machineries are discussed, as well as how interaction of the U1 snRNP with 3' terminal exons might contribute to mRNA export.     

Ovine placental lactogen induces somatomedin: a a possible role in fetal growth

Ovine placental lactogen (oPL) and bovine growth hormone (bGH) increase the circulating concentration of somatomedin in hypophysectomized rats. This finding indicates that some of the somatotropic properties of oPL may be due to the induction of somatomedin and raises the possibility that oPL has a role in the control of fetal growth.     

Characterization of soluble E-cadherin as a disease marker in gastric cancer patients

The soluble fragment of E-cadherin protein (S-ECD) is reported to be increased in the peripheral blood of cancer patients. In this study, we investigated the clinical significance of serum S-ECD in 81 patients with gastric cancer. The amount of serum S-ECD was significantly higher in the gastric cancer patients (4735 +/- 2310 ng ml(-1)) than in healthy volunteers (2515 +/- 744 ng ml(-1)). With the normal range cut-off at average +2 s.d., 67% patients showed abnormally high serum S-ECD levels. This frequency was significantly higher than that of other tumour markers, such as CEA (4.4%) or CA19-9 (13.3%). However, there was no significant correlation between the amount of S-ECD and clinicopathological factors. Serum S-ECD might be derived from cancer tissue, as removal of cancers by surgical treatment results in quick decline of the serum S-ECD and S-ECD can be detected by immunoblot in cancer tissues but not in normal epithelium. The serum S-ECD amount was compared with the E-cadherin expression in cancer tissues, which were classified into those showing preserved (+), partially reduced (+/-) or lost (-) expression. Interestingly, E-cadherin (+/-) tumours showed higher serum S-ECD levels than the other types, and a higher amount of S-ECD in the immunoblot analysis. Thus, the serum level of S-ECD may serve as an excellent tumour marker with high sensitivity. Furthermore, analysis of S-ECD in serum and cancer tissue can offer clues for elucidating the mechanism of reduction of E-cadherin expression in cancer cells.