Abstract P4-04-04: Polarity Abnormalities in Invasive Carcinomas of the Breast: Analysis of Invasive Micropapillary Carcinoma of the Breast

Aims: Invasive micropapillary carcinomas (IMPC) are rare (<2% of all invasive breast carcinomas) and characterized by clusters of cells with an inverted polarity surrounded by a clear space that separate them from the extracellular matrix. These tumors harbor vascular invasion and axillary lymph node involvement in more than 70% of the cases. We performed a detailed analysis of cellular polarity in a series of 25 IMPC to get insight in the putative role of proteins involved in the maintenance of cellular polarity in that carcinoma subtype.

Methods: Polarity analysis has been performed by immunohistochemistry on a tissue-micro-array of a series of twenty-five invasive micropapillary carcinomas. Apical (p-ERM, a marker of phosphorylated ezrin, moesin and radixin, aPKCz, MUC1 and GM130, a marker of the golgi apparatus), basal (collagen IV), or baso-lateral (EGFR, E-cadherin, b-catenin and ERBB2) markers were assessed.

Results: Apical markers MUC1, aPKCz, P-ERM were expressed at the external cellular pole in 88% (22/25), 60% (15/25) and 40% (10/25) of the cases respectively. Notably, 15/25 (60%) were p-ERM negative. Twenty-four cases/25 (96%) demonstrated a GM130 localisation at the external pole of the cells, with an abnormal internal and external localisation of the labelling in 15/24 positive cases (62%). Finally, 24% (6/25) cases presented all these apical markers located at the external part of the cells and 92% (23/25) had at least one of the apical markers in external position. The large majority of the cases (96%; 24/25) demonstrated no collagen IV labelling at the external part of the cell clusters. Intercellular junction proteins E-cadherin and b-catenin were expressed in all cases with a complete absence of staining at the apical inverted pole for both markers. Interestingly, a thick and strong labelling was observed for E-cadherin and for b-catenin in 36% (9/25) and 92% (23/25) of the cases respectively. EGFR was negative in 24 out of the 25 cases (96%). In contrast, ERBB2 was overexpressed in 6/25 (24%) of cases with a membranous ERBB2 labelling except external at the inverted apical pole. EGFR and ERBB2 are considered in normal cells as a baso-lateral marker. Conclusion: IMPC present a clear inverted apical pole MUC-1 and/or aPKCz and/or phospho-ERM positive with the golgi apparatus facing the external membrane of cell clusters, oriented towards the clear space and the extracellular matrix. The intercellular junctions in IMPC are abnormal with a thick E-cadherin and b-catenin labelling compared to normal cells. These abnormal cell orientation and junctions could be a consequence of molecular alterations that are currently being analysed in our laboratory, and that could explain the high frequency of loco-regional lymphatic tumor extension observed in IMPC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-04-04.

The HPCSA and radiology

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Intracellular Pasteurella pseudotuberculosis: Multiplication in Cultured Spleen and Kidney Cells

Pasteurella pseudotuberculosis multiplied within rabbit cells in primary culture. Spleen cells from rabbits were either dispersed mechanically, exposed to the organism immediately after cell preparation, and grown as a pellet or the cells were dispersed enzymatically and grown as a monolayer for 4 to 6 days before the bacteria were introduced. Intracellular multiplication proceeded at a logarithmic rate for 1 to 2 days, with a generation time of about 70 min in pelleted cells and 4 to 5 hr in monolayered cells. Under the conditions employed, the wild-type virulent strain and an avirulent mutant multiplied at similar rates. Atmosphere, constituents of the medium, and multiplicity of infection influenced intracellular proliferation. The organism also proliferated in kidney cells. Microscopic observation of stained cells indicated limited growth of the pathogen in spleen cells at 37 C. In kidney cells, the pasteurellae localized in compartments; frequently, a single compartment with masses of proliferating organisms almost filled the cytoplasm.

Effects of new Phoneutria spider toxins on glutamate release and [Ca2+]i in rat cortical synaptosomes

Studies revealed that the venom of the Brazilian "armed" spider Phoneutria nigriventer contains potent neurotoxins that caused excitatory symptoms such as salivation, lachrymation, priapism, convulsions, flaccid and spastic paralysis. It was also reported that the main mechanism of action of those neurotoxins are effects on ion channels such as inhibition of the inactivation of Na+ channels, blockage of K+ channels and blockage of calcium channels. The venom from Phoneutria keyserlingi, as might be expected, contains a series of polypeptides that are very similar, but not identical, to the proteins previously obtained from the venom of P. nigriventer in terms of their amino acid sequences and biological activities. We evaluated the effects of some of the toxins of P. nigriventer and P. keyserlingi on glutamate release and the decrease in [Ca2+]i by using synaptosomes of rat brain cortices and fluorimetric assays. Sequence comparisons between the Phoneutria toxins of both the species showed great similarity in the location of cysteine residues. However, thus far, no pharmacological assays were performed to evaluate the extension of those biochemical modifications. Our results showed that differences between the amino acid sequences of Phoneutria toxins of both the species lead to the significant changes in the pharmacological properties of these toxins.

Ovipositional preferences of the Japanese beetle (Coleoptera: Scarabaeidae) among warm- and cool-season turfgrass species

Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), were evaluated for ovipositional preferences among four turfgrasses common in northwestern Arkansas. Choice assays revealed females preferred to oviposit in tall fescue (Festuca arundinacea Schreb.) and zoysiagrass (Zoysia japonica Steud.), and that they avoided oviposition in common bermudagrass (Cynodon dactylon [L.] Pers.) and hybrid bermudagrass (C. dactylon x C. transvaalensis Pers.). Significantly fewer eggs were oviposited in hybrid bermudagrass in a no-choice assay, suggesting that chemical and/or physical plant characteristics deter oviposition in that grass. The percentage of turfgrass cores with evidence of female activity (presence of female or eggs, or signs of female digging) in choice assays revealed no differences among treatments, yet significantly fewer hybrid bermudagrass cores had eggs. These results suggest that many females did not initially reject hybrid bermudagrass based on aboveground plant characteristics, but rather they left without ovipositing. Therefore, resistance in hybrid bermudagrass is likely expressed below ground. Our results suggest that the use of hybrid bermudagrass as a means of cultural control in an integrated pest management program may discourage Japanese beetle oviposition and subsequent grub infestations in lawns, golf courses, or sports fields.

Detection and molecular characterization of filamentous actinobacteria and thermoactinomycetes present in water-damaged building materials

In this study the dominant filamentous actinobacteria occurring in water-damaged building materials were detected by culture and characterized by automated ribotyping and 16S rRNA gene sequencing. Fifty-two samples were taken from 20 water-damaged houses in four different countries. A total of 122 bacterial isolates were analyzed. Actinobacteria or thermoactinomycetes were present in 48% of the samples. The dominant genus was Streptomyces (58% of isolates), followed by Thermoactinomyces (23%), Laceyella (14%), Nocardiopsis (3%), Pseudonocardia (1%) and Saccharomonospora (1%). The most frequently detected species was the thermophilic Thermoactinomyces vulgaris (14 samples/4 countries). The most common streptomycetes were closely related to the heterogeneous species Streptomyces microflavus (7/2) or Streptomyces griseus (6/2). Automated ribotyping was a rapid tool for reliable characterization of these isolates. The spores of thermoactinomycetes and toxic substances of Nocardiopsis species and S. griseus may constitute a risk for human health.

PRACTICAL IMPLICATIONS

Harmful microbes in indoor environments are a cause of public concern. To develop rapid and simple-to-use molecular biological methods to detect the presence of harmful actinobacterial species in water-damaged buildings more information about their occurrence in those materials is needed, which this study provides.