Expression Pattern Of Galectin-3 Research Articles

Evaluation of galectin-3, β-catenin, and nuclear morphometry in different thyroid lesions

This study aimed to evaluate the expression pattern of galectin-3 and β-catenin and assess the nuclear morphometric features of different thyroid lesions in order to investigate their diagnostic significance. Sixty specimens of benign and malignant thyroid lesions, in addition to 10 cases of normal thyroid tissue used as control, were immunohistochemically stained with antibodies against galectin-3 and β-catenin. Hematoxylin and eosin-stained slides were examined using image analyzer Proplus V software. Morphological parameters measured included mean nuclear diameter, mean nuclear perimeter, and mean nuclear area. Cytoplasmic immunoreactivity for galectin-3 was strongest in papillary thyroid carcinomas (88.9%), whereas staining was less intense in the follicular variant of papillary thyroid carcinoma and in follicular (60 and 75%, respectively) and poorly differentiated carcinomas (28.6%); it was expressed focally and weakly in follicular adenoma cases and even more weakly in the reactive follicular epithelium of nodular goiter (P<0.5). Membrane β-catenin expression was decreased in only two of 13 (15.4%) adenomas and in 21 of 38 (55.3%) carcinomas (P<0.5). Among carcinomas, reduced membrane β-catenin was associated with progressive loss of tumor differentiation and increased invasiveness (P<0.5). The mean nuclear diameter and the mean nuclear perimeter were higher in undifferentiated carcinomas when compared with other subtypes and were the least for follicular neoplasms. Galectin-3 immunostaining and analysis of β-catenin dysregulation may be useful as an adjunct to distinguish benign from malignant thyroid lesions. Quantitative estimation of nuclear features can play a role in assessment of the morphological features and thus help in the diagnosis of thyroid lesions.

Runx2 is expressed in human glioma cells and mediates the expression of galectin‐3

Runx2 is a member of the Runx family of transcription factors (Runx1-3) with a restricted expression pattern. It has so far been detected predominantly in skeletal tissues where, inter alia, it regulates the expression of the beta-galactoside-specific lectin galectin-3. Here we show that, in contrast to Runx3, Runx1 and Runx2 are expressed in a variety of human glioma cells. Runx2 expression pattern in these cells correlated completely with that of galectin-3, but not with that of other galectins. A similar correlation in the expression pattern of galectin-3 and Runx2 transcripts was detected in distinct types of 70 primary neural tumors, such as glioblastoma multiforme, but not in others, such as gangliocytomas. In glioma cells, Runx2 is directly involved in the regulation of galectin-3 expression, as shown by RNAi and transcription factor binding assays demonstrating that Runx2 interacts with a Runx2-binding motif present in the human galectin-3 promoter. Knockdown of Runx2 was thus accompanied by a reduction of both galectin-3 mRNA and protein levels by at least 50%, dependent on the glial tumor cell line tested. Reverse transcriptase-polymerase chain reaction analyses, aimed at finding other potential target genes of Runx2 in glial tumor cells, revealed the presence of bone sialoprotein, osteocalcin, osteopontin, and osteoprotegerin. However, their expression patterns only partially overlap with that of Runx2. These data suggest a functional contribution of Runx-2-regulated galectin-3 expression to glial tumor malignancy.

Expression pattern of galectin-3 in neural tumor cell lines

Galectin-3 is a member of the galectin family of beta-galactoside-specific animal lectins. Here we show that galectin-3 is constitutively expressed in 15 out of 16 glioma cell lines tested, but not by normal or reactive astrocytes, oligodendrocytes, glial O-2A progenitor cells and the oligodendrocyte precursor cell line Oli-neu. Galectin-3 is also expressed by one oligodendroglioma cell line, but not by primitive neuroectodermal tumor and 4 neuroblastoma cell lines tested so far. In all galectin-3 expressing cell lines, the lectin is predominantly, if not exclusively, localized intracellularly and carries an active carbohydrate recognition domain (shown for C6 rat glioma cells). Moreover, in contrast to primary astrocytes, glioma cells do not or only weakly adhere to substratum-bound galectin-3, probably reflecting an unusual glycosylation pattern. Our findings indicate that the expression of galectin-3 selectively correlates with glial cell transformation in the central nervous system and could thus serve as a marker for glial tumor cell lines and glial tumors.

Decreased expression of galectin-3 in basal cell carcinoma of the skin.

Galectins are beta-galactoside-binding lectins that play multiple roles during tumor progression. Previous work conducted in our laboratory has demonstrated decreased galectin-3 expression in carcinomas from colon, breast, ovary and endometrium, compared to the corresponding normal tissues. In this study, we examined the pattern of galectin-3 expression by immunohistochemistry in a group of 10 basal cell carcinomas of the skin. In the surrounding normal skin, galectin-3 immunostaining was found predominantly in the middle epidermis (spine layer) and eccrine sweat glands. Compared to the normal epidermal cells, basal carcinoma cells observed in all 10 samples examined presented with significantly decreased galectin-3 immunostaining. These data further demonstrates that galectin-3 is down-regulated in a variety of human cancers, including basal cell carcinoma.