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Evaluation of Isoforms from Cratylia mollis Seed Lectin as Histochemical Markers for Human Prostatic Tissues
Lima, A. L. R 1,2*; Silva, M. C. C.1; Cavalcanti, C. L. B.2; Paiva, P. M. G.1; Coelho, L. C. B. B.1; Beltrão, E. I. C.1,2 & Correia, M. T. S1
1Departamento de Bioquímica, CCB, Fone: 2126-8540, 2Laboratório de Imunopatologia Keiso Asami – LIKA; Universidade Federal de Pernambuco (UFPE), 50670-901, Recife-PE, e-mail: *amandresse@hotmail.com
Lectins are proteins or glycoproteins, which recognize specifically and reversibly free or conjugated carbohydrates. Through this ability, they have been used in histochemistry to evaluate changes in the composition and expression of cell-surface and cytoplasm oligossacharides in processes of cellular development and differentiation as well as in pathologies. The aim of this work was to evaluate isoforms from Cratylia mollis seed lectin (Cramoll 1,4 glucose/mannose-specific and Cramoll 3 galactose-specific), conjugated to horseradish peroxidase (HRP), as potential histochemical markers for normal and neoplasic tissues of human prostate. The lectins were purified by chromatographic methods, previously established, and conjugated to peroxidase. Biopsies slices (4 µm) from normal prostate, benign prostatic hyperplasia (BPH) and prostatic carcinoma (PCA) were treated with 0.1% (w/v) trypsin and 0.3% (v/v) methanol-H2O2 solutions and incubated with HRP-conjugated lectins (15, 30 and 45 µg/mL). Lectin staining was visualized with a solution of diaminobenzidine-H2O2. Sections were counter-stained with haematoxylin and evaluated by optic microscopy. Inhibition assays of lectin-carbohydrate binding were carried out with the specific sugar of each isoform at a concentration of 0.3M. Cramoll 1,4 (15 µg/mL) stained weakly and heterogeneously the cytoplasm of normal cell. However for BPH and PCA staining was stronger and homogeneous than that observed in the normal tissue. Cramoll 1,4 stained mainly the apical cellular membrane of hyperplasic cells, while the neoplasic ones presented only a cytoplasmatic staining. Stroma presented a weak staining pattern in normal and neoplasic tissues and a moderate pattern in BPH. Cramoll 3 (45 μg/mL) failed to recognize normal tissue. BPH and PCA were not differentially stained showing a weak and heterogeneous pattern, even using a higher lectin concentration. These results suggest Cramoll 1,4 as an auxiliary tool in histochemistry contributing to the identification of biochemical changes in cell glycoconjugate profiles and in differential diagnosis between BPH and PCA. Supported by: CNPq, FACEPE and CAPES
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