Tubulin detyrosination is a frequent occurrence in breast cancers of poor prognosis.

Tubulin, the dimeric subunit of microtubules, is a major cell protein that is centrally involved in cell division. Tubulin is subject to specific enzymatic posttranslational modifications including cyclic tyrosine removal and addition at the COOH terminus of the alpha-subunit. Tubulin is normally extensively tyrosinated in cycling cells. However, we have previously shown that detyrosinated tubulin accumulates in cancer cells during tumor progression in nude mice. Tubulin detyrosination, resulting from suppression of tubulin tyrosine ligase and the resulting unbalanced activity of tubulin-carboxypeptidase, apparently represents a strong selective advantage for cancer cells. We have now analyzed the occurrence and significance of tubulin detyrosination in human breast tumors. We studied a total of 134 breast cancer tumors from patients with or without known complications over a follow-up period of 31 +/- 10 months. The mean age of the patients at the time of diagnosis was 57 years. For each patient, detailed data concerning the histology and extension of the tumor were available. Tumor cells containing detyrosinated tubulin were visualized by immunohistochemical staining of paraffin-embedded tissue sections. Cancer cells with detyrosinated tubulin were observed in 53% of the tumors and were predominant in 19.4% of the tumors. Tubulin detyrosination correlated to a high degree of significance (P < 0.001) with a high Scarf-Bloom-Richardson (SBR) grade, a known marker of tumor aggressiveness. Among SBR grade 1 tumors, 3.8% were strongly positive for tubulin detyrosination compared with 65.4% of the SBR grade 3 tumors. The SBR component showing the strongest correlation with tubulin detyrosination was the mitotic score. In the entire patient population, neither the SBR grade nor the detyrosination index had significant prognostic value (P = 0.11, P = 0.27, respectively), whereas a combined index was significantly correlated with the clinical outcome (P = 0.02). A preliminary subgroup analysis indicated that tubulin detyrosination may define high- and low- risk groups in breast cancer tumors with an SBR grade of 2. Our study shows that tubulin detyrosination is a frequent occurrence in breast cancer, easy to detect, and linked to tumor aggressiveness.

Expression of E-, P-, n-cadherins and catenins in human bladder carcinoma cell lines.

PURPOSE: Cadherins are cell surface glycoproteins that mediate Ca2+-dependent, homophilic cell-cell adhesion. The classical cadherins, E-, P- and N-cadherins, are known to self-associate from their extracellular domain, while their cytoplasmic domain interacts with either beta-catenin or plakoglobin (gamma-catenin), which in turn is bound to alpha-catenin that links the complex to the actin cytoskeleton. The aim of the present study was to analyze the expression of E-, P- and N-cadherins and catenins in human bladder carcinoma cells. MATERIALS AND METHODS: Five human bladder carcinoma cell lines, representing a variety of differentiation states, were grown in cell culture. We performed a cell aggregation assay, specific for biological cadherin activity. The expression of cadherins and catenins was analyzed by immunocytochemistry, Western blotting and RT-PCR. The interactions between cadherins and catenins were assessed by immunoprecipitation. RESULTS: We observed a reduced E-cadherin expression in the poorly differentiated and invasive-tumor derived cells. Interestingly, immunofluorescence study reveals the persistent localization of catenins at intercellular contacts in two E-cadherin deficient cell lines (T24 and TCCSUP) which yet exhibit an epithelial-like morphology and a calcium-dependent adhesive capacity. This suggests that other cadherin(s) are expressed in these both cell lines. P-cadherin, another epithelial cadherin, is expressed only in E-cadherin positive cells. On the other hand, N-cadherin is present at cell-cell borders in the very anaplastic cell lines, T24 and TCCSUP, and is able to link beta-catenin or plakoglobin. CONCLUSION: These results indicate that N-cadherin may participate in intercellular adhesion, while facilitating bladder tumorigenesis.

Chromosome 11 aneuploidy detected by fluorescent in situ hybridization (FISH) in breast cancer: relation with progesterone receptor expression.

Progesterone receptor (PR) expression is known to be impaired in breast cancer. As the PR gene is located on chromosome 11 which is also often affected, we studied their relationship in 15 patients with breast carcinoma. Tumoural imprints were used for PR immunocytochemistry and for FISH with chromosome 11 centromeric probes. Distribution profiles of chromosome 11 number in PR+ and PR- cell populations were examined. No difference in the number of chromosome 11 was found between PR+ and PR- breast tumours. Thus, loss of PR expression in breast cancer cannot be explained only by loss of chromosome 11; other genetic or non-genetic mechanisms should be advanced.

Expression of three cell adhesion molecules in bladder carcinomas: correlation with pathological features.

Recently, independent studies have shown that the expression of two integrin chains, beta 4 and alpha 2, plus the epithelial cadherin are related to tumour progression in human bladder carcinomas. For the first time, we compare the expression of these three cell adhesion molecules using immunohistochemical analysis of consecutive cryosections from a series of 50 bladder tumors. E-cadherin, beta 4, and alpha 2 were strongly expressed in normal urothelium. A majority of non-invasive bladder cancers stained positively for E-cadherin (62%), whereas only 29% expressed normal positivity for alpha 2, and only 35% for beta 4. However, most invasive tumours presented an aberrant expression of alpha 2 (81%), beta 4 (100%), and E-cadherin (75%). We studied the correlation of immunoreactivity with histological grade and stage. The alpha 2 pattern was not correlated with stage and grade. In contrast, loss of normal beta 4 expression was significantly related to increasing tumour grade and deep invasion with a higher correlation for grade. Finally, E-cadherin expression was highly correlated with stage, but not with grade. Thus our results indicate that, although many invasive bladder tumours presented a disorder in expression of the two integrins alpha 2 and beta 4, E-cadherin appeared to be a better market of invasiveness in bladder carcinomas.

Expression of E-cadherin and alpha-,beta- and gamma-catenins in human bladder carcinomas: are they good prognostic factors?

E-cadherin, the epithelium-specific cadherin, is known to play a major role in tumor progression in many human carcinomas, via intercellular homophilic Ca2+-dependent adhesion. This adhesion is mediated by a group of cytoplasmic proteins, including the alpha-, beta- and gamma-catenins that link the E-cadherin to the actin cytoskeleton. Recent studies have shown that loss or reduction of either E-cadherin or catenin expression was strictly related to clinicopathological data in bladder tumors, and E-cadherin might constitute prognostic factors in bladder carcinogenesis. Here we continued a preliminary work on E-cadherin in bladder cancer. In an effort to evaluate their possible prognostic value, we investigated both E-cadherin and catenins in 99 bladder tumors by immunohistochemistry. E-cadherin and all the catenins were strongly expressed in normal urothelium. Regarding histopathological data, the tumors examined showed that the disrupted expression of each molecule, except for gamma-catenin, was directly related to increasing tumor grade (mainly for alpha- and beta-catenin) and deep invasion (p < or = 0.01). The aberrant expression of E-cadherin and beta-catenin was also correlated to the presence of distant metastasis (p < 0.05). However, only abnormal expression of a-catenin was associated with poor survival (p = 0.037). Therefore our results suggest that alpha-catenin is directly involved in tumor invasion and dedifferentiation and is the only protein of any prognostic value, albeit low in patients with bladder cancer.

Methods for simultaneous interphase in situ hybridization and nuclear antigen immunocytochemistry in T47-D cells.

Procedures that combine immunocytochemistry (ICC) and in situ hybridization (ISH) techniques are now used to investigate phenotype/genotype relationships in the same cells. In this report we describe three rapid procedures for simultaneous detection of a nuclear antigen, progesterone receptors (PR), and the centromeric region of chromosome 11 (to which the human PR gene has been assigned) in T47-D cells. Proteins were stained by precipitates of horseradish peroxidase-diaminobenzidine (PO-DAB, brown color), alkaline phosphatase-Fast Red (APase-Fast Red, red color) or alkaline phosphatase-nitroblue tetrazolium-X-phosphate (APase-NBT-X-Phosphate, blue color) respectively. To obtain a suitable contrast for the two labels, we detected DNA on PO-DAB and APase-NBT-X-phosphate-immunostained cells with interphasic fluorescent in situ hybridization (FISH). By contrast, we combined the APase-Fast Red ICC with an immunocytochemical ISH using alkaline phosphatase-NBT-X-phosphate detection. Only the procedure combining APase-NBT-X-phosphate ICC and FISH ensures optimal visualization of both the PR content and the number of chromosome 11. This method easily provides simultaneous localization of DNA and protein targets in the same cells and should be applicable to many other situations.

Amino acids in normal and diabetic ducks.

The transient diabetes, observed in ducks after subtotal pancreatectomy, induces hyperglycaemia and hyperamino-acidaemia. Threonine and alanine are quantitatively the most important amino acids in both normal and diabetic animals, suggesting a particular role of threonine in amino acid metabolic pathways in the duck. The hyperaminogenic role of the decreased insulin levels, and the neoglucogenic effect of a low, but not negligible, glucagon secretion, during diabetes, are discussed.