Expression patterns of α2,3-sialyltransferase I and α2,6-sialyltransferase I in human cutaneous epithelial lesions.

Skin tumors have become one of the most common cancers in the world and their carcinogenesis is frequently associated with altered glycosylation patterns. The aberrant sialylation, a type of glycosylation, can mediate pathophysiological key events during various stages of tumor progression, including invasion and metastasis. Sialyltransferases play a key role in a variety of biological processes, including cell-cell communication, cell-matrix interaction, adhesion, and protein targeting. In this study, it was evaluated the expression of ST3Gal I and ST6Gal I in cutaneous epithelial lesions that include actinic keratosis (n=15), keratoacanthoma (n=9), squamous cell carcinoma (n=22) and basal cell carcinoma (n=28) in order to evaluate if sialyltransferases expression is different in premalignant and in malignant tumors. The expression of ST3Gal I was observed in actinic keratosis (53%), keratoacanthoma (78%), squamous cell carcinoma (73%) and basal cell carcinoma (32%) with statistic differences between basal cell carcinoma and keratoacanthoma (P=0.0239) and basal cell carcinoma and squamous cell carcinoma (P=0.0096); for ST6Gal I, cytoplasmic expression was noted in actinic keratosis (40%), heterogeneous and cytoplasmic expression was noted in keratoacanthoma (67%), squamous cell carcinoma (41%) and basal cell carcinoma (7%) with statistic differences between basal cell carcinoma and squamous cell carcinoma (P=0.0061) and basal cell carcinoma and keratoacanthoma (P=0.0008). In summary, our results showed that the high expression of ST3Gal I and ST6Gal I, in skin tumors, is associated with tumors with greater potential for invasion and metastasis, as in the case of squamous cell carcinoma, and this may be related to their behavior.

Sialic acid differential expression in non-melanoma skin cancer biopsies.

Altered sialylation has been observed during oncogenic transformation and has been implicated in tumor progression and metastases. This pattern may aid the biological behavior of many tumors. Skin cancer is the most common cancer worldwide and their diagnosis becomes difficult, in some cases, due to variety of factors that affect the accuracy of the nowadays exams, such as huge spectrum of tumors and their variants. So, this study investigates the changes in expression and distribution of α2,3 and α2,6-linked sialic acid in non-melanomas skin cancer to identify the sialylation pattern which may be useful in the differential diagnosis of this tumor. Lectin histochemistry was used to examine the expression and distribution of sialic acid in different types of non-melanoma skin cancers. We applied Maackia amurensis lectin, which interacts with α2,3-linked sialic acid and Sambucus nigra lectin specific for α2,6-linked sialic acid. The histochemical analysis showed that α2,3 and α2,6-linked sialic acid vary their expression according with the tumor type analyzed. The distribution of α2,3-linked sialic was differentially expressed in between basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) (p < 0.0001), BCC and actinic keratosis (p = 0.0033) and BCC and keratoacanthoma (p < 0.0001). In the case of α2,6-linked sialic acid its expression was also different between BCC and SCC (p < 0.0001), BCC and actinic keratosis (p = 0.0002) and BCC and keratoacanthoma (p < 0.0362). Lectin histochemistry showed a different expression of both sialic acid linkages types between pre-malign and malign tumors and between malign tumors. Although preliminary, these findings are promising for the development of diagnostic techniques to help in the differential diagnosis of non-melanoma skin tumors using lectin histochemistry as an auxiliary tool.

Acridinium ester conjugated to lectin as chemiluminescent histochemistry marker.

Cell differentiation/dedifferentiation includes changes in oligosaccharide composition and distribution in the cell surface glycoconjugates. Lectins have been used as auxiliary tools in histopathological diagnosis of mammary, uterus and brain pathologies. Acridinium ester (AE) conjugated to biomolecules has been employed in chemiluminescent analytical applications. This work aimed to use a lectin, concanavalin A (Con A), conjugated to AE as a chemiluminescent histochemistry tool. Biopsies of normal and infiltrating duct carcinoma (IDC) of mammary tissues were treated by a Con A-AE derivative. Photon emission, observed during the breakage of the chemical bound between Con A and AE, was quantified, expressed in relative light units (RLU) and correlated to the labelling of the normal and transformed tissues. The results demonstrated that RLU presented a linear relationship with the labelled tissue area in the range 0.125-1.0 cm2 (r=0.98). Furthermore, RLU was much higher for the IDC (1283.920x103+/-220.621x103) than the normal tissue (2.565x103+/-0.247x103), namely, about 500 times higher. The Con A-AE conjugation efficiency, differential staining of normal and IDC tissues, and quantification of results contribute to a decrease in the subjectivity in routine histopathological diagnoses and indicate that acrydinum ester can join other lectin marker to be used in histochemistry.

Esquistossomose murina esperimental: estudo imunohistoquímicos das células ganglionares mioentéricas / Experimental murine Schistosomiasis: an immunohistochemical study of the ganglionic myoenteric cells

Para estudar a influência do processo granulomatoso esquistossomóticosobre as células ganglionares mioentéricas, foram utilizados 30 camundongos albinos Swiss infectadoscom 50 cercárias da cepa SLM do S. mansoni.O grupo controle foi constituído por dez animais näo infectados. Após sessenta dias de infecçäo, cortes histológicos do intestino delgadocorados por hematoxilina-eosina e P.A.S. demonstraram granulomas periovulares em todas as camadas da parede intestinal. Através do método imunohistoquímico indireto, usando-se a enolase neurônio-específica como marcador, observou-se desorganizaçäo do plexo mioentêrico em áreas contendo granulomas. Além disso, ocorreu rarefaçäo das estaçöes ganglionares, com aparente destruiçäo de células neuronais. A possível contribuiçäo dessas alteraçöes para a sintomatologia da esquistossomose humana é avaliada