The role of galectin-3 in the tumorigenesis and progression of pituitary tumors

Galectin inhibitors and nanoparticles as a novel therapeutic strategy for glioblastoma multiforme

Over the past two decades, the gold standard of glioblastoma multiforme (GBM) treatment is unchanged and adjunctive therapy has offered little to prolong both quality and quantity of life. To improve pharmacotherapy for GBM, galectins are being studied provided their positive correlation with the malignancy and disease severity. Despite the use of galectin inhibitors and literature displaying the ability of the lectin proteins to decrease tumor burden and decrease mortality within various malignancies, galectin inhibitors have not been studied for GBM therapy. Interestingly, anti-galectin siRNA delivered in nanoparticle capsules, assisting in blood brain barrier penetrance, is well studied for GBM, and has demonstrated a remarkable ability to attenuate both galectin and tumor count. Provided that the two therapies have an analogous anti-galectin effect, it is hypothesized that galectin inhibitors encapsuled within nanoparticles will likely have a similar anti-galectin effect in GBM cells and further correlate to a repressed tumor burden.

Increased Gal-3 Mediates Microglia Activation and Neuroinflammation via the TREM2 Signaling Pathway in Prion Infection

Galectin 3 (Gal-3) is one of the major elements for activating microglia and mediating neuroinflammation in some types of neurodegenerative diseases. However, its role in the pathogenesis of prion disease is seldom addressed. In this study, markedly increased brain Gal-3 was identified in three scrapie-infected rodent models at the terminal stage. The increased Gal-3 was mainly colocalized with the activated microglia. Coincidental with the increased brain Gal-3 in prion-infected animals, the expression of brain trigger receptor expressed in myeloid cell 2 (TREM2), one of the Gal-3 receptors, and some components in the downstream pathway also significantly increased, whereas Toll-like receptor 4 (TLR4), another Gal-3 receptor, and the main components in its downstream signaling were less changed. The increased Gal-3 signals were distributed at the areas with PrPSc deposit but looked not to colocalize directly with PrPSc/PrP signals. Similar changing profiles of Gal-3, the receptors TREM2 and TLR4, as well as the proteins in the downstream pathways were also observed in prion-infected cell line SMB-S15. Removal of PrPSc replication in SMB-S15 cells reversed the upregulation of cellular Gal-3, TREM2, and the relevant proteins. Moreover, we presented data for interactions of Gal-3 with TREM2 and with TLR4 morphologically and molecularly in the cultured cells. Stimulation of prion-infected cells or their normal partner cells with recombinant mouse Gal-3 in vitro induced obvious responses for activation of TREM2 signaling and TLR4 signaling. Our data here strongly indicate that prion infection or PrPSc deposit induces remarkably upregulated brain Gal-3, which is actively involved in the microglia activation and neuroinflammation mainly via TREM2 signaling.

Exploration of the Effects of TGF-β Pathway-Based Pituitary Tumor of Rats on GH3 Cell Line after Intervention with Different Concentrations of TGZ

The effect of the TGF-β pathway-based pituitary tumor of rats on the GH3 cell line after intervention with different concentrations of troglitazone (TGZ) is explored. The CH3 cell line of 24 clean male SD rats with pituitary adenoma is selected. The cells are divided into a blank contrast set and an experimental set. The experimental set is divided into different TGZ concentration sets, including 1 × 10-3 TGZ set, 1 × 10-4 TGZ set, and 1 × 10-5 TGZ set. The cell proliferation is detected by the CCK-8 method, the protein expressions of CD147, TGF-β1, and MMP-9 are detected by the western blot method, and the relative mRNA expressions of CD147, TGF-β1, and MMP-9 are detected by the qRT-PCR method. The expression levels of CD147, TGF-β1, and MMP-9 in CH3 cells of pituitary adenoma rats are notoriously lower, while the expression of CD147, TGF-31, and MMP-9 could be reduced by TGZ acting on the GH3 cell line. The specific mechanism of action of this effect on the invasive ability of GH3 cell lines is multifaceted, suggesting that peroxisome proliferator activator-receptor (PPAR-γ) agonists have good clinical application prospects in tumor therapy and can provide new targets and approaches for tumor drug therapy.

Targeted disruption of galectin 3 in mice delays the first wave of spermatogenesis and increases germ cell apoptosis

Galectin 3 is a multifunctional lectin implicated in cellular proliferation, differentiation, adhesion, and apoptosis. This lectin is broadly expressed in testicular somatic cells and germ cells, and is upregulated during testicular development. Since the role of galectin 3 in testicular function remains elusive, we aimed to characterize the role of galectin 3 in testicular physiology. We found that galectin 3 transgenic mice (Lgals3-/-) exhibited significantly decreased testicular weight in adulthood compared to controls. The transgenic mice also exhibited a delay to the first wave of spermatogenesis, a decrease in the number of germ cells at postnatal day 5 (P5) and P15, and defective Sertoli cell maturation. Mechanistically, we found that Insulin-like-3 (a Leydig cell marker) and enzymes involved in steroid biosynthesis were significantly upregulated in adult Lgals3-/- testes. These observations were accompanied by increased serum testosterone levels. To determine the underlying causes of the testicular atrophy, we monitored cellular apoptosis. Indeed, adult Lgals3-/- testicular cells exhibited an elevated apoptosis rate that is likely driven by downregulated Bcl-2 and upregulated Bax and Bak expression, molecules responsible for live/death cell balance. Moreover, the percentage of testicular macrophages within CD45+ cells was decreased in Lgals3-/- mice. These data suggest that galectin 3 regulates spermatogenesis initiation and Sertoli cell maturation in part, by preventing germ cells from undergoing apoptosis and regulating testosterone biosynthesis. Going forward, understanding the role of galectin 3 in testicular physiology will add important insights into the factors governing the development of germ cells and steroidogenesis and delineate novel biomarkers of testicular function.

[Expression and Clinical Significance of Galcetin-3 in the Serum of Non-small Cell Lung Cancer Patients]

背景与目的

肺癌是对人类健康威胁最大的疾病之一, 发病率高, 死亡率高。早期肺癌可以通过外科手术得到根治, 因此, 肺癌的早期发现及早期治疗尤其重要。血清肿瘤标志物是发现及诊断肺癌的一个重要手段。目前已知, 半乳糖凝集素3(Galectin-3)在多种恶性肿瘤中均有表达。该研究旨在探讨Galectin-3在非小细胞肺癌患者血清中的表达水平及其临床意义。

方法

采用酶联免疫吸附法检测并比较69例非小细胞肺癌患者与77例健康人群外周血血清Galectin-3浓度, 并分析其表达水平与肺癌临床特征之间的关系。

结果

Galectin-3在非小细胞肺癌患者外周血血清中的表达水平高于健康人群, 差异具有显著统计学意义(P < 0.01)；有淋巴结转移的非小细胞肺癌患者, Galectin-3表达水平显著高于无淋巴结转移患者, 差异有显著统计学意义(P < 0.01)；N2淋巴结转移的患者Galectin-3表达水平显著高于N1淋巴结转移的患者, 差异有显著统计学意义(P < 0.01)；临床Ⅲ期+Ⅳ期患者Galectin-3表达水平显著高于临床Ⅰ期+Ⅱ期患者, 差异有统计学意义(P < 0.05)。

结论

非小细胞肺癌患者血清Galectin-3水平呈现高表达, 与肺癌转移相关, 可能是一种潜在的肺癌肿瘤标志物。

Integrated Bioinformatics Analysis Reveals Key Candidate Genes and Pathways Associated With Clinical Outcome in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for approximately 85-90% of all liver cancer cases and has poor relapse-free survival. There are many gene expression studies that have been performed to elucidate the genetic landscape and driver pathways leading to HCC. However, existing studies have been limited by the sample size and thus the pathogenesis of HCC is still unclear. In this study, we performed an integrated characterization using four independent datasets including 320 HCC samples and 270 normal liver tissues to identify the candidate genes and pathways in the progression of HCC. A total of 89 consistent differentially expression genes (DEGs) were identified. Gene-set enrichment analysis revealed that these genes were significantly enriched for cellular response to zinc ion in biological process group, collagen trimer in the cellular component group, extracellular matrix (ECM) structural constituent conferring tensile strength in the molecular function group, protein digestion and absorption, mineral absorption and ECM-receptor interaction. Network system biology based on the protein-protein interaction (PPI) network was also performed to identify the most connected and important genes based on our DEGs. The top five hub genes including osteopontin (SPP1), Collagen alpha-2(I) chain (COL1A2), Insulin-like growth factor I (IGF1), lipoprotein A (LPA), and Galectin-3 (LGALS3) were identified. Western blot and immunohistochemistry analysis were employed to verify the differential protein expression of hub genes in HCC patients. More importantly, we identified that these five hub genes were significantly associated with poor disease-free survival and overall survival. In summary, we have identified a potential clinical significance of these genes as prognostic biomarkers for HCC patients who would benefit from experimental approaches to obtain optimal outcome.

Galectins and Ovarian Cancer

Ovarian cancer is known for its aggressive pathological features, including the capacity to undergo epithelial to mesenchymal transition, promoting angiogenesis, metastatic potential, chemoresistance, inhibiting apoptosis, immunosuppression and promoting stem-like features. Galectins, a family of glycan-binding proteins defined by a conserved carbohydrate recognition domain, can modulate many of these processes, enabling them to contribute to the pathology of ovarian cancer. Our goal herein was to review specific galectin members identified in the context of ovarian cancer, with emphasis on their association with clinical and pathological features, implied functions, diagnostic or prognostic potential and strategies being developed to disrupt their negative actions.

A Galactoside-Binding Protein Tricked into Binding Unnatural Pyranose Derivatives: 3-Deoxy-3-Methyl-Gulosides Selectively Inhibit Galectin-1

Galectins are a family of galactoside-recognizing proteins involved in different galectin-subtype-specific inflammatory and tumor-promoting processes, which motivates the development of inhibitors that are more selective galectin inhibitors than natural ligand fragments. Here, we describe the synthesis and evaluation of 3-C-methyl-gulopyranoside derivatives and their evaluation as galectin inhibitors. Methyl 3-deoxy-3-C-(hydroxymethyl)-β-d-gulopyranoside showed 7-fold better affinity for galectin-1 than the natural monosaccharide fragment analog methyl β-d-galactopyranoside, as well as a high selectivity over galectin-2, 3, 4, 7, 8, and 9. Derivatization of the 3-C-hydroxymethyl into amides gave gulosides with improved selectivities and affinities; methyl 3-deoxy-3-C-(methyl-2,3,4,5,6-pentafluorobenzamide)-β-d-gulopyranoside had Kd 700 µM for galectin-1, while not binding any other galectin.

Neuroanatomical Quantitative Proteomics Reveals Common Pathogenic Biological Routes between Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD)

(1) Background: Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative disorders with an overlap in clinical presentation and neuropathology. Common and differential mechanisms leading to protein expression changes and neurodegeneration in ALS and FTD were studied trough a deep neuroproteome mapping of the spinal cord. (2) Methods: A liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of the spinal cord from ALS-TAR DNA-binding protein 43 (TDP-43) subjects, ubiquitin-positive frontotemporal lobar degeneration (FTLD-U) subjects and controls without neurodegenerative disease was performed. (3) Results: 281 differentially expressed proteins were detected among ALS versus controls, while 52 proteins were dysregulated among FTLD-U versus controls. Thirty-three differential proteins were shared between both syndromes. The resulting data was subjected to network-driven proteomics analysis, revealing mitochondrial dysfunction and metabolic impairment, both for ALS and FTLD-U that could be validated through the confirmation of expression levels changes of the Prohibitin (PHB) complex. (4) Conclusions: ALS-TDP-43 and FTLD-U share molecular and functional alterations, although part of the proteostatic impairment is region- and disease-specific. We have confirmed the involvement of specific proteins previously associated with ALS (Galectin 2 (LGALS3), Transthyretin (TTR), Protein S100-A6 (S100A6), and Protein S100-A11 (S100A11)) and have shown the involvement of proteins not previously described in the ALS context (Methanethiol oxidase (SELENBP1), Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN-1), Calcyclin-binding protein (CACYBP) and Rho-associated protein kinase 2 (ROCK2)).

Galectin-3-Mediated Glial Crosstalk Drives Oligodendrocyte Differentiation and (Re)myelination

Galectin-3 (Gal-3) is the only chimeric protein in the galectin family. Gal-3 structure comprises unusual tandem repeats of proline and glycine-rich short stretches bound to a carbohydrate-recognition domain (CRD). The present review summarizes Gal-3 functions in the extracellular and intracellular space, its regulation and its internalization and secretion, with a focus on the current knowledge of Gal-3 role in central nervous system (CNS) health and disease, particularly oligodendrocyte (OLG) differentiation, myelination and remyelination in experimental models of multiple sclerosis (MS). During myelination, microglia-expressed Gal-3 promotes OLG differentiation by binding glycoconjugates present only on the cell surface of OLG precursor cells (OPC). During remyelination, microglia-expressed Gal-3 favors an M2 microglial phenotype, hence fostering myelin debris phagocytosis through TREM-2b phagocytic receptor and OLG differentiation. Gal-3 is necessary for myelin integrity and function, as evidenced by myelin ultrastructural and behavioral studies from LGALS3^-/- mice. Mechanistically, Gal-3 enhances actin assembly and reduces Erk 1/2 activation, leading to early OLG branching. Gal-3 later induces Akt activation and increases MBP expression, promoting gelsolin release and actin disassembly and thus regulating OLG final differentiation. Altogether, findings indicate that Gal-3 mediates the glial crosstalk driving OLG differentiation and (re)myelination and may be regarded as a target in the design of future therapies for a variety of demyelinating diseases.

RNA interference-mediated Gal-3 knockdown inhibits proliferation and promotes apoptosis of pancreatic cancer cells

AIM

To investigate the effect of RNA interference-mediated knockdown of galectin-3 (Gal-3) on the proliferation and apoptosis of pancreatic cancer cells and the possible mechanism involved.

METHODS

Cultured Panc-1 cells were randomly divided into a control group (untreated), an NC group (transfected with control siRNA) and a Gal-3 interference group (transfected with Gal-3-siRNA). After using small interfering RNA (siRNA) technology to interfere with the expression of Gal-3 in Panc-1 cells, Gal-3 expression was detected by RT-PCR and Western blot, cell proliferation was measured by CCK-8 assay, and cell apoptosis was tested by flow cytometry. The expression of Ki67, cleaved caspase-3, and β-catenin proteins was examined by Western blot.

RESULTS

Compared with the control group, there was no significant difference in the expression of Gal-3 mRNA (0.99 ± 0.08 vs 1.01 ± 0.06) or protein (0.36 ± 0.03 vs 0.34 ± 0.05) in the NC group (P > 0.05), while the expression of Gal-3 mRNA (0.38 ± 0.02 vs 1.01 ± 0.06) and protein (0.10 ± 0.01 vs 0.34 ± 0.05) in the Gal-3 interference group was significantly decreased (P < 0.05). Compared with the control group, RNA interference-mediated knockdown of Gal-3 significantly decreased cell proliferation (24 h: 0.55 ± 0.03 vs 0.71 ± 0.05; 48 h: 0.76 ± 0.05 vs 0.97 ± 0.06; 72 h: 1.08 ± 0.06 vs 1.32 ± 0.09), increased the percentage of cells in G0/G1 stage (79.48 ± 1.32 vs 71.52 ± 1.15), reduced the percentage of cells in S (14.26 ± 1.08 vs 18.24 ± 1.06 ) and G2/M stages (6.21 ± 0.78 vs 10.19 ± 1.52), increased apoptosis (13.26 ± 2.28 vs 5.82 ± 0.35), downregulated the expression of Ki67 (0.24 ± 0.02 vs 0.96 ± 0.07), cyclin D1 (0.26 ± 0.03 vs 0.88 ± 0.09), and β-catenin (0.42 ± 0.05 vs 0.87 ± 0.05), and upregulated the expression of cleaved caspase-3 (0.70 ± 0.06 vs 0.32 ± 0.03) (P < 0.05 for all). There was no significant difference in the above indexes between the NC group and control group (P > 0.05).

CONCLUSION

RNA interference-mediated Gal-3 knockdown can inhibit proliferation and promote apoptosis of pancreatic cancer cells via mechanisms that may be related to the inhibition of the Wnt/ beta-catenin signaling pathway.