Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Mac-2 lectin (carbohydrate binding protein 35) is a soluble, 32- to 35-kDa phosphoprotein that binds galactose-containing glycoconjugates. We report here that the colonic epithelium is a major site of Mac-2 expression in vivo based on immunohistochemistry of human tissue specimens. In this epithelium, proliferating cells at the base of the crypts do not express Mac-2 but its expression increases with differentiation along the crypt-to-surface axis. Mac-2 expression is concentrated in the nuclei of these differentiated epithelial cells. The progression from normal mucosa to adenoma to carcinoma is associated with significant changes in Mac-2 nuclear localization and expression. In all adenomas (9/9) and carcinomas (13/13) examined, Mac-2 was not present in the nucleus but was localized in the cytoplasm. Sequencing of Mac-2 cDNAs from normal mucosa and carcinoma revealed no specific mutations that could account for this loss of nuclear localization. We also observed a 5- to 10-fold decrease in Mac-2 mRNA levels in cancer compared to normal mucosa as well as a significant reduction in the amount of Mac-2 protein expressed. These observations suggest that Mac-2 exclusion from the nucleus and its decreased expression may be related to the neoplastic progression of colon cancer.
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PMID:Decreased expression of Mac-2 (carbohydrate binding protein 35) and loss of its nuclear localization are associated with the neoplastic progression of colon carcinoma. 768 4

Galectin-3, a beta-galactoside-binding protein, has been shown to be involved in tumor progression and metastasis. Here, we demonstrate that expression of galectin-3 in human breast carcinoma BT549 cells inhibits cis-diamminedichloroplatinum (cisplatin)-induced poly(ADP-ribose) polymerase degradation and apoptosis, without altering Bcl-2, Bcl-X(L), or Bax expressions. Galectin-3 contains the NWGR amino acid sequence highly conserved in the BH1 domain of the bcl-2 gene family, and a substitution of glycine to alanine in this motif abrogated its antiapoptotic activity. Our findings demonstrate that galectin-3 inhibits apoptosis through a cysteine protease pathway and highlight the functional significance of the NWGR motif in apoptosis resistance of a non-Bcl-2 protein.
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PMID:Galectin-3: a novel antiapoptotic molecule with a functional BH1 (NWGR) domain of Bcl-2 family. 939 48

Galectin-1 and galectin-3 are galactoside-binding proteins involved in different steps of tumor progression and potential targets for therapy. We have investigated the expression of these galectins in 38 human bladder transitional-cell carcinomas of different histological grade and clinical stage and in 5 normal urothelium samples. Galectin-1 mRNA levels were highly increased in most high-grade tumors compared with normal bladder or low-grade tumors. Western blot and immuno-histochemical analysis of normal and neoplastic tissues revealed a higher content of galectin-1 in tumors. Galectin-3 mRNA levels were also increased in most tumors compared with normal urothelium, but levels were comparable among tumors of different histological grade.
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PMID:galectin-1 and galectin-3 expression in human bladder transitional-cell carcinomas. 998 30

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.
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PMID:Decreased expression of galectin-3 in basal cell carcinoma of the skin. 1037 95

Galectin-3 is a beta-galactoside-specific lectin that binds to laminin sugar-sites and is involved in tumor malignancy. Galectin-3 expression in relation to primary tumor and liver metastasis of colorectal cancer was examined to determined its involvement in cancer progression and metastasis. Immunohistochemical staining of galectin-3 was performed on 117 primary lesions and 15 liver metastases of colorectal cancer using TIB166 monoclonal antibody. The expression of galectin-3 was evaluated by grading the intensity of the staining as either negative, weakly positive, or strongly positive. Normal mucosa of all patients were strongly positive for galectin-3, but the staining in these tissues was still significantly less than in the primary lesions of the cancer (31.6%). Galectin-3 expression in the primary lesions was significantly increased, correlating with the progression of clinical stage (p=0. 0224), liver metastasis (p<0.0001), venous invasion (p=0.0048), and lymph node metastasis (p=0.0289). Liver metastatic lesions also showed up-regulated levels of galectin-3 compared to the primary lesions (p=0.0030). The group showing strongly positive galectin-3 had a significantly poorer prognosis than the negative/weakly positive group in terms of disease-free survival (p=0.0224). The strong expression of galectin-3 in colorectal cancer correlates with cancer progression, liver metastasis, and poor prognosis for patients.
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PMID:Involvement of galectin-3 expression in colorectal cancer progression and metastasis. 1037 7

Galectin-3 is a member of a growing family of animal beta-galactoside-binding proteins shown to be involved in cell growth, differentiation, apoptosis resistance, and tumor progression. In the present study, we investigated whether galectin-3 can protect against apoptosis induced by the loss of cell anchorage (anoikis). Because studies suggest that cellular sensitivity to anoikis is associated with cell cycle regulation, we examined the role of galectin-3 on cell cycle regulation. Although BT549 cells (human breast epithelial cells) undergo anoikis, galectin-3-overexpressing BT549 cells respond to the loss of cell adhesion by inducing G1 arrest without detectable cell death. Galectin-3-mediated G1 arrest involves down-regulation of G1-S cyclin levels (cyclin E and cyclin A) and up-regulation of their inhibitory protein levels (p21(WAF1/CIP1) and p27KIP1). After the loss of cell anchorage, Rb protein becomes hypophosphorylated in galectin-3-overexpressing cells, as predicted from the flow cytometric analysis and immunoblot analysis of cyclins and their inhibitors. Interestingly, galectin-3 induces cyclin D1 expression (an early G1 cyclin) and its associated kinase activity in the absence of cell anchorage. On the basis of these results, we propose that galectin-3 inhibition of anoikis involves cell cycle arrest at an anoikis-insensitive point (late G1) through modulation of gene expression and activities of cell cycle regulators. The present study suggests that galectin-3 may be a critical determinant for anchorage-independent cell survival of disseminating cancer cells in the circulation during metastasis.
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PMID:Cell cycle arrest and inhibition of anoikis by galectin-3 in human breast epithelial cells. 1046 21

Galectin-3 is a member of the beta-galactoside-binding protein family shown to be involved in tumor progression and metastasis. It has a unique primary structure consisting of three domains: a 12-amino acid leader sequence containing a casein kinase I serine phosphorylation site, which is preceded by a collagenase-sensitive Pro-Gly-rich motif, and a COOH-terminal half encompassing the carbohydrate-binding site. To study the functional role of the unusual leader sequence of galectin-3, a mutant cDNA that causes an 11-amino acid deletion in the NH2-terminal region was generated and expressed in galectin-3-null BT-549 human breast carcinoma cells. Deletion of the NH2 terminus resulted in abolition of the secretion of truncated galectin-3, loss of nuclear localization, and reduced carbohydrate-mediated functions compared with the wild-type protein. When green fluorescent protein was fused to the galectin-3 leader sequence and transiently transfected into BT-549 cells, the uniform cellular distribution of native green fluorescent protein was changed mainly to a nuclear pattern. To further investigate whether the functional changes observed in a galectin-3 with the 11 NH2-terminal amino acids deleted were due to loss of phosphorylation at Ser6, two point mutations were created at this serine: Ser6-->Ala and Ser6-->Glu. No obvious difference was observed in cellular localization between wild-type and Ser6-mutated transfectants. These results suggest a structural role for the NH2 terminus leader motif of galectin-3 in determining its cellular targeting and biological functions independent of phosphorylation.
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PMID:The NH2 terminus of galectin-3 governs cellular compartmentalization and functions in cancer cells. 1062 18

Galectin-3 is a carbohydrate-binding protein endowed with affinity for beta-galactosides. It plays a role in cell-cell and cell-matrix interactions. Furthermore, it has been hypothesized to be involved in tumor progression and metastasis. To address the role of galectin-3 in the invasive and metastatic processes, we stably overexpressed galectin-3 in human breast carcinoma cell lines, and we evaluated the influence of elevated galectin-3 expression on several cell features, including cellular homotypic and heterotypic interactions and cell survival. No differences in various parameters related with cell growth features and proliferation were detected. By contrast, we found that galectin-3 overexpressing cells, with respect to low galectin-3 expressing cells, exerted: (1) a significantly enhanced adhesion to laminin, fibronectin and vitronectin exerted both directly or via increased expression of specific integrins, e.g., alpha-4 and beta-7; (2) a remodeling of those cytoskeletal elements associated with cell spreading, i.e., microfilaments; (3) an enhanced survival upon exposure to different apoptotic stimuli, such as cytokine and radiation. Collectively, our results indicate that overexpression of galectin-3 may play a role in tumor cell invasion and metastasis by specifically influencing cell adhesion to the extracellular matrix. This may confer selective survival advantage and resistance to the particular homeless-induced apoptosis called anoikia.
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PMID:Galectin-3 overexpression protects from apoptosis by improving cell adhesion properties. 1069 29

Galectin-3, a member of the beta-galactoside-binding animal lectins, has been implicated in tumor invasion and metastasis. Using an immunoligand assay, we assessed the circulating levels of galectin-3 in sera from cancer patients as well as from healthy controls. Low serum levels of galectin-3 were detected in healthy individuals (median, 62 ng/ml; range, 20-313 ng/ml; 95th percentile, 184.3 ng/ml). Compared with healthy individuals, galectin-3 serum levels in patients with breast, gastrointestinal, lung, or ovarian cancer, melanoma, and non-Hodgkin's lymphoma were significantly elevated (P = 0.014). Moreover, galectin-3 concentrations in sera from patients with metastatic disease were higher than in sera from patients with localized tumors. Maximum serum concentrations of galectin-3 (median, 320 ng/ml; range, 20-950 ng/ml) were found in patients with metastatic gastrointestinal carcinoma. These results suggest that circulating galectin-3 may play a role in tumor progression. The possibility of using this assay in early-stage cancer to predict metastasis should be studied.
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PMID:Concentrations of galectin-3 in the sera of normal controls and cancer patients. 1077 68

The accurate determination of levels of differentiation is of prognostic value in human head and neck squamous cell carcinomas (HNSCCs). Because the deliberate selection of biochemical determinants accompanying certain stages of differentiation can refine the predictive power of histochemical assessments, the application of the quantitative evaluation of staining distribution and intensity by computer-assisted microscopy is one prerequisite to potential improvements. We used 2 innovative approaches with peanut agglutinin based on encouraging results with respect to common lectin-histochemistry. First, we used a custom-made neoglycoprotein to monitor the presence of Thomsen-Friedenreich (T) antigen-binding sites. Second, we measured the presence of 2 galectins immunohistochemically and, at the same time, measured lectin-histochemically the presence of accessible ligands for the endogenous lectins. We also monitored the presence of calcyclin, a protein with relevance to cell cycle progression or exocytosis. With 61 cases of HNSCC as their basis, including 31 oral, 20 laryngeal, and 10 hypopharyngeal lesions, the data show that the main modifications observed in connection with a loss of differentiation are related to a modification in the levels of both galectin-3/galectin-3-binding site and T-antigen/T-antigen-binding site expressions. The data obtained also suggest that galectin-3 could act as an acceptor site for the T antigen. Because the level of differentiation is known to be indicative of the recurrence rate in HNSCCs and our data clearly indicate that galectin-3 and the T antigen (and their respective binding sites) are involved in dedifferentiation processes, further investigation is warranted into the roles of galectins in HNSCC tumor progression and recurrence analysis.
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PMID:Correlation of galectin-3/galectin-3-binding sites with low differentiation status in head and neck squamous cell carcinomas. 1082 95


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