The Differential Expression of Galectin-1 and Galectin-3 in Normal Lymphoid Tissue and Non-Hodgkin's and Hodgkin's Lymphomas

Biomarkers in Cancer Detection, Diagnosis, and Prognosis

Biomarkers are vital in healthcare as they provide valuable insights into disease diagnosis, prognosis, treatment response, and personalized medicine. They serve as objective indicators, enabling early detection and intervention, leading to improved patient outcomes and reduced costs. Biomarkers also guide treatment decisions by predicting disease outcomes and facilitating individualized treatment plans. They play a role in monitoring disease progression, adjusting treatments, and detecting early signs of recurrence. Furthermore, biomarkers enhance drug development and clinical trials by identifying suitable patients and accelerating the approval process. In this review paper, we described a variety of biomarkers applicable for cancer detection and diagnosis, such as imaging-based diagnosis (CT, SPECT, MRI, and PET), blood-based biomarkers (proteins, genes, mRNA, and peptides), cell imaging-based diagnosis (needle biopsy and CTC), tissue imaging-based diagnosis (IHC), and genetic-based biomarkers (RNAseq, scRNAseq, and spatial transcriptomics).

Galectin Family Members: Emerging Novel Targets for Lymphoma Therapy?

The galectin family of proteins has high affinity with β-galactoside-containing glycans. These proteins participate in cell growth and differentiation, cell adhesion, cell signal transduction, cell apoptosis, and other cellular activities. In recent years, a large number of studies have described the expression and correlation of galectins in different tumors. Each member of the family plays a vital role in tumor growth, progression, angiogenesis, adhesion, and tumor immune escape. Studies on the roles of galectins in lymphoma have mainly involved galectin-1, -3, -7, and -9. The results suggest that galectins may become novel targets for precise tumor treatment. This article reviews current research progress regarding galectins in lymphoma and provides new ideas for exploring them as novel targets for treating lymphoma and other important medical issues.

Epigenetic, Metabolic, and Immune Crosstalk in Germinal-Center-Derived B-Cell Lymphomas: Unveiling New Vulnerabilities for Rational Combination Therapies

B-cell non-Hodgkin lymphomas (B-NHLs) are highly heterogenous by genetic, phenotypic, and clinical appearance. Next-generation sequencing technologies and multi-dimensional data analyses have further refined the way these diseases can be more precisely classified by specific genomic, epigenomic, and transcriptomic characteristics. The molecular and genetic heterogeneity of B-NHLs may contribute to the poor outcome of some of these diseases, suggesting that more personalized precision-medicine approaches are needed for improved therapeutic efficacy. The germinal center (GC) B-cell like diffuse large B-cell lymphomas (GCB-DLBCLs) and follicular lymphomas (FLs) share specific epigenetic programs. These diseases often remain difficult to treat and surprisingly do not respond advanced immunotherapies, despite arising in secondary lymphoid organs at sites of antigen recognition. Epigenetic dysregulation is a hallmark of GCB-DLBCLs and FLs, with gain-of-function (GOF) mutations in the histone methyltransferase EZH2, loss-of-function (LOF) mutations in histone acetyl transferases CREBBP and EP300, and the histone methyltransferase KMT2D representing the most prevalent genetic lesions driving these diseases. These mutations have the common effect to disrupt the interactions between lymphoma cells and the immune microenvironment, via decreased antigen presentation and responsiveness to IFN-γ and CD40 signaling pathways. This indicates that immune evasion is a key step in GC B-cell lymphomagenesis. EZH2 inhibitors are now approved for the treatment of FL and selective HDAC3 inhibitors counteracting the effects of CREBBP LOF mutations are under development. These treatments can help restore the immune control of GCB lymphomas, and may represent optimal candidate agents for more effective combination with immunotherapies. Here, we review recent progress in understanding the impact of mutant chromatin modifiers on immune evasion in GCB lymphomas. We provide new insights on how the epigenetic program of these diseases may be regulated at the level of metabolism, discussing the role of metabolic intermediates as cofactors of epigenetic enzymes. In addition, lymphoma metabolic adaptation can negatively influence the immune microenvironment, further contributing to the development of immune cold tumors, poorly infiltrated by effector immune cells. Based on these findings, we discuss relevant candidate epigenetic/metabolic/immune targets for rational combination therapies to investigate as more effective precision-medicine approaches for GCB lymphomas.

LAG-3 is expressed on a majority of tumor infiltrating lymphocytes in pediatric Hodgkin lymphoma

LAG-3, through interaction with a variety of ligands, regulates T cell function via inhibition of T cell proliferation and activation. It has been demonstrated to be overexpressed on tumor infiltrating lymphocytes (TILs) of a variety of cancers with associated poor outcomes. The purpose of this study is to characterize the expression pattern and clinical significance of LAG-3 in pediatric Hodgkin lymphoma (HL). Patient tumor samples from Children's Oncology Group clinical trial AHOD0031 with matched patient outcome data were analyzed for the expression of LAG-3 and PD-L1 using immunohistochemistry. 73/115 patients (63%) demonstrated positive LAG-3 staining. No demographic or survival outcome data were significantly associated with LAG-3 expression. Interestingly, patients with the lowest density of expression were found to have the worst EFS, and those with highest density of expression demonstrated the best EFS. There was a positive statistically significant relationship between presence of LAG-3 and PD-L1 expression. This project is innovative in its characterization of LAG-3 as an immune checkpoint target in pediatric HL.

Prognostic impact of glioblastoma stem cell markers OLIG2 and CCND2

Aims

Glioblastoma (GBM) is the most common and lethal malignant brain tumor in adults. Glioma stem cells (GSCs) are implicated in this poor prognosis and in radio(chemo‐)resistance. We have previously demonstrated that among potentially highly specific GSC markers oligodendrocyte lineage transcription factor 2 (OLIG2) appears to be the most specific and cyclin D2 (CCND2) the only one related to cell cycle regulation. The purpose of this work was to investigate the clinical significance and the evolution of OLIG2 and CCND2 protein expression in GBM.

Methods and results

Immunohistochemical expression analysis of Olig2 and Ccnd2 was carried out on a cohort of human paired GBM samples comparing initial resections with local recurrent tumors after radiation therapy (RT) alone or radio‐chemotherapy with temozolomide (RT‐TMZ). Uni‐ and multivariate logistic regression analysis revealed that significant risk factors predicting early mortality (<12 months) are: subtotal surgery for recurrence, time to recurrence <6 months, Ccnd2 nuclear expression at initial surgery ≥30%, and Olig2 nuclear expression <30% at second surgery after RT alone and RT‐TMZ.

Conclusions

We demonstrated that patients for whom nuclear expression of Olig2 becomes low (<30%) after adjuvant treatments have a significantly shorter time to recurrence and survival reflecting most probably a proneural to mesenchymal transition of the GSCs population. We also highlighted the fact that at initial surgery, high nuclear expression (≥30%) of CCND2, a G1/S regulator specific of GSCs, has a prognostic value and is associated with early mortality (<12 months).

The Prognostic Value of the Combination of Low VEGFR-1 and High VEGFR-2 Expression in Endothelial Cells of Colorectal Cancer

Research on tumor angiogenesis has mainly focused on the vascular endothelial growth factor (VEGF) family and on methods to block its actions. However, reports on VEGF receptor (VEGFR) expression in tumor-associated endothelial cells (ECs) are limited. Thus, we evaluated VEGF, VEGFR-1 and VEGFR-2 expression in ECs of colorectal cancer (CRC) using immunohistochemistry. VEGF, VEGFR-1 and -2 expression in ECs was quantitatively evaluated by digital image analysis in a retrospective series of 204 tumor tissue samples and related to clinical variables. The data show that the VEGF, VEGFR-1 and VEGFR-2 expression in ECs is heterogeneous. Multivariate analysis including a set of clinicopathological variables reveals that high EC VEGFR-1 expression is an independent prognostic factor for overall survival (OS). The combination of low VEGFR-1 and high VEGFR-2 expression in ECs outperforms models integrating VEGFR-1 and VEGFR-2 as separate markers. Indeed, this VEGFR-1_VEGFR-2 combination is an independent negative prognostic factor for OS (p = 0.012) and metastasis-free survival (p = 0.007). In conclusion, this work illustrates the importance of studying the distribution of VEGF members in ECs of CRC. Interestingly, our preliminary data suggest that high VEGFR-1 and low VEGFR-2 expression in ECs appear to be involved in the progression of CRC, suggesting that targeting EC VEGFR-1 could offer novel opportunities for CRC treatment. However, a prospective validation study is needed.

Endogenous Galectin-1 in T Lymphocytes Regulates Anti-prostate Cancer Immunity

The identification of effective new therapies for prostate cancer (PCa) requires a better understanding of the multiple molecular interactions between tumor cells and their associated microenvironment. In this context, galectin-1 (Gal-1) is a key molecule in the determination of the prostatic carcinoma microenviroment; therefore, it is essential to understand all the molecular processes in which this protein is involved. Most of the previous studies found in the literature have focused on the microenvironment remodeling properties of tumor-secreted Gal-1, through its interactions with the glyco-receptors at the cell membrane and the extracellular matrix. This report shows original aspects of the lectin by focusing on the role of lymphocyte endogenous Gal-1 in controlling anti-prostate tumor immunity. Using a murine preclinical model of prostate cancer, our results demonstrate that endogenous Gal-1 in lymphocytes modulates their proliferative rate and cytotoxic function in conditions of high extracellular Gal-1 concentration, mainly derived from tumor cells. In such conditions, the absence of Gal-1 in T lymphocytes potentiates anti-tumor immune responses. Further studies demonstrated that endogenous Gal-1 in CD4+, but mainly in CD8+T cells, acts as a negative regulator of anti-tumor immunity. In conclusion, prostate tumors require Gal-1 in lymphocytes to evade immune responses. This report lays the foundation for an original immunotherapy strategy for prostate cancer.

Galectins as regulators of cell survival in the leukemia niche

The microenvironment within the bone marrow (BM) contains support cells that promote leukemia cell survival and suppress host anti-tumor defenses. Galectins are a family of beta-galactoside binding proteins that are critical components in the tumor microenvironment. Galectin 1 (LGALS1) and Galectin 3 (LGALS3) as regulators of RAS signaling intracellularly and as inhibitors of immune cells extracellularly are perhaps the best studied members for their role in leukemia biology. Interest in Galectin 9 (LGALS9) is growing as this galectin has been identified as an immune checkpoint molecule. LGALS9 also supports leukemia stem cells (LSCs) though a mechanism of action is not clear. LGALS1 and LGALS3 each participate in a diverse number of survival pathways that promote drug resistance by supporting pro-tumor molecules such BCL2, MCL-1, and MYC and blocking tumor suppressors like p53. Acute myeloid leukemia (AML) BM mesenchymal stromal cells (MSC) have protein signatures that differ from healthy donor MSC. Elevated LGALS3 protein in AML MSC is associated with refractory disease/relapse demonstrating that MSC derived galectin impacts patient survival. LGALS3 is a critical determining factor whether MSC differentiate into adipocytes or osteoblasts so the galectin influences the cellular composition of the leukemia niche. Both LGALS3 and LGALS1 when secreted can suppress immune function. Both galectins can induce apoptosis of T cells. LGALS3 also modulates T cell receptor endocytosis and impairs interferon mediated chemokine production by binding glycosylated interferon. LGALS3 as a TIM3 binding partner acts to suppress T cell function. Galectins also impact leukemia cell mobilization and may participate in homing mechanisms. LGALS3 participates in transport mechanism of integrins, receptors, and other molecules that control cell adhesion and cell:cell interactions. The diversity of these various functions demonstrate the importance of these galectins in the leukemia niche. This review will cover the role of LGALS1, LGALS3, and LGALS9 in the various processes that are critical for maintaining leukemia cells in the tumor microenvironment.

Proteomic Identification of the Galectin-1-Involved Molecular Pathways in Urinary Bladder Urothelial Carcinoma

Among various heterogeneous types of bladder tumors, urothelial carcinoma is the most prevalent lesion. Some of the urinary bladder urothelial carcinomas (UBUCs) develop local recurrence and may cause distal invasion. Galectin-1 de-regulation significantly affects cell transformation, cell proliferation, angiogenesis, and cell invasiveness. In continuation of our previous investigation on the role of galectin-1 in UBUC tumorigenesis, in this study, proteomics strategies were implemented in order to find more galectin-1-associated signaling pathways. The results of this study showed that galectin-1 knockdown could induce 15 down-regulated proteins and two up-regulated proteins in T24 cells. These de-regulated proteins might participate in lipid/amino acid/energy metabolism, cytoskeleton, cell proliferation, cell-cell interaction, cell apoptosis, metastasis, and protein degradation. The aforementioned dys-regulated proteins were confirmed by western immunoblotting. Proteomics results were further translated to prognostic markers by analyses of biopsy samples. Results of cohort studies demonstrated that over-expressions of glutamine synthetase, alcohol dehydrogenase (NADP⁺), fatty acid binding protein 4, and toll interacting protein in clinical specimens were all significantly associated with galectin-1 up-regulation. Univariate analyses showed that de-regulations of glutamine synthetase and fatty acid binding protein 4 in clinical samples were respectively linked to disease-specific survival and metastasis-free survival.

Radiation-enhanced therapeutic targeting of galectin-1 enriched malignant stroma in triple negative breast cancer

Currently there are no FDA approved targeted therapies for Triple Negative Breast Cancer (TNBC). Ongoing clinical trials for TNBC have focused primarily on targeting the epithelial cancer cells. However, targeted delivery of cytotoxic payloads to the non-transformed tumor associated-endothelium can prove to be an alternate approach that is currently unexplored. The present study is supported by recent findings on elevated expression of stromal galectin-1 in clinical samples of TNBC and our ongoing findings on stromal targeting of radiation induced galectin-1 by the anginex-conjugated arsenic-cisplatin loaded liposomes using a novel murine tumor model. We demonstrate inhibition of tumor growth and metastasis in response to the multimodal nanotherapeutic strategy using a TNBC model with orthotopic tumors originating from 3D tumor tissue analogs (TTA) comprised of tumor cells, endothelial cells and fibroblasts. The ‘rigorous’ combined treatment regimen of radiation and targeted liposomes is also shown to be well tolerated. More importantly, the results presented provide a means to exploit clinically relevant radiation dose for concurrent receptor mediated enhanced delivery of chemotherapy while limiting overall toxicity. The proposed study is significant as it falls in line with developing combinatorial therapeutic approaches for stroma-directed tumor targeting using tumor models that have an appropriate representation of the TNBC microenvironment.

Role of galectin-1 in urinary bladder urothelial carcinoma cell invasion through the JNK pathway

Human galectin-1 is a member of the galectin family, proteins with conserved carbohydrate-recognition domains that bind galactoside. Galectin-1 is highly expressed in various tumors and participates in various oncogenic processes. However, detailed descriptions of the function of galectin-1 in urinary bladder urothelial carcinoma have not been reported. Our previous cohort investigation showed that galectin-1 is associated with tumor invasiveness and is a possible independent prognostic marker of urinary bladder urothelial carcinoma. The present study aimed to clarify the relevance of galectin-1 expression level to tumor progression and invasion. In order to decipher a mechanism for the contribution of galectin-1 to the malignant behavior of urinary bladder urothelial carcinoma, two bladder cancer cell lines (T24 and J82) were established with knockdown of galectin-1 expression by shRNA. Bladder cancer cells with LGALS1 gene silencing showed reduced cell proliferation, lower invasive capability, and lower clonogenicity. Extensive signaling pathway studies indicated that galectin-1 participated in bladder cancer cell invasion by mediating the activity of MMP9 through the Ras-Rac1-MEKK4-JNK-AP1 signaling pathway. Our functional analyses of galectin-1 in urinary bladder urothelial carcinoma provided novel insights into the critical role of galectin-1 in tumor progression and invasion. These results revealed that silencing the galectin-1-mediated MAPK signaling pathway presented a novel strategy for bladder cancer therapy.

Primary Central Nervous System (CNS) Lymphoma B Cell Receptors Recognize CNS Proteins

Primary lymphoma of the CNS (PCNSL) is a diffuse large B cell lymphoma confined to the CNS. To elucidate its peculiar organ tropism, we generated recombinant Abs (recAbs) identical to the BCR of 23 PCNSLs from immunocompetent patients. Although none of the recAbs showed self-reactivity upon testing with common autoantigens, they recognized 1547 proteins present on a large-scale protein microarray, indicating polyreactivity. Interestingly, proteins (GRINL1A, centaurin-α, BAIAP2) recognized by the recAbs are physiologically expressed by CNS neurons. Furthermore, 87% (20/23) of the recAbs, including all Abs derived from IGHV4-34 using PCNSL, recognized galectin-3, which was upregulated on microglia/macrophages, astrocytes, and cerebral endothelial cells upon CNS invasion by PCNSL. Thus, PCNSL Ig may recognize CNS proteins as self-Ags. Their interaction may contribute to BCR signaling with sustained NF-κB activation and, ultimately, may foster tumor cell proliferation and survival. These data may also explain, at least in part, the affinity of PCNSL cells for the CNS.

Galectin expression in cancer diagnosis and prognosis: A systematic review

Galectins are a family of proteins that bind to specific glycans thereby deciphering the information captured within the glycome. In the last two decades, several galectin family members have emerged as versatile modulators of tumor progression. This has initiated the development and preclinical assessment of galectin-targeting compounds. With the first compounds now entering clinical trials it is pivotal to gain insight in the diagnostic and prognostic value of galectins in cancer as this will allow a more rational selection of the patients that might benefit most from galectin-targeted therapies. Here, we present a systematic review of galectin expression in human cancer patients. Malignant transformation is frequently associated with altered galectin expression, most notably of galectin-1 and galectin-3. In most cancers, increased galectin-1 expression is associated with poor prognosis while elevated galectin-9 expression is emerging as a marker of favorable disease outcome. The prognostic value of galectin-3 appears to be tumor type dependent and the other galectins require further investigation. Regarding the latter, additional studies using larger patient cohorts are essential to fully unravel the diagnostic and prognostic value of galectin expression. Furthermore, to better compare different findings, consensus should be reached on how to assess galectin expression, not only with regard to localization within the tissue and within cellular compartments but also regarding alternative splicing and genomic variations. Finally, linking galectin expression and function to aberrant glycosylation in cancer cells will improve our understanding of how these versatile proteins can be exploited for diagnostic, prognostic and even therapeutic purposes in cancer patients.

Galectin-13/PP-13 expression in term placentas of gestational diabetes mellitus pregnancies

INTRODUCTION

Gestational diabetes mellitus (GDM) is an increasing harm in pregnancy. Inflammatory processes in the placenta seem to have an influence on pathogenesis besides known factors like maternal BMI. Galectin-13 (gal-13) is an immunoregulatory protein, which is suspected to play a role in development of GDM in the placenta.

METHODS

A total of 40 placentas were obtained from women treated for gestational diabetes mellitus. Placental tissue for control group was obtained from 40 women with normal pregnancy. We investigated the protein expression of gal-13 in term placentas with immunohistochemistry and immunofluorescence. Immunohistochemical staining was analyzed with the semi-quantified IRS score. Gal-13 serum levels were performed with ELISA on a total of 20 probes from women with GDM and healthy control pregnancies in the third trimester.

RESULTS

Gal-13 was found in syncytiotrophoblast, in nuclei of syncytiotrophoblast and trophoblast cells as well in extravillous trophoblast cells of normal placentas. In GDM placentas, gal-13 expression was significantly decreased in all of these examined cell types (syncytiotrophoblast p = 0.003, nuclei of syncytiotrophoblast p = 0.007; extravillous trophoblast cells p = 0.001). The ELISA showed a significant lower gal-13 serum level in blood from pregnant women with GDM in comparison to healthy controls.

DISCUSSION

As gal-13 with its anti-inflammatory functions plays a role in regulation of maternal immune system, a lack of gal-13 may contribute to an imbalance in inflammation processes in the placenta during pregnancy and therefore influences development of GDM.

Identification of OLIG2 as the most specific glioblastoma stem cell marker starting from comparative analysis of data from similar DNA chip microarray platforms

Despite advances in surgical and adjuvant treatments, overall survival of glioblastoma (GBM) patients remains poor. The cancer stem cell concept suggests that a rare stem cell population, called glioma stem cells (GSCs), has high ability to self-renewal leading to recurrence in GBM. The identification of specific markers of GSCs would provide a powerful tool to detect and to characterise them in order to develop targeted therapies. We carried out a comparative analysis based on the identification of inter-study concordances to identify the genes that exhibit at best differential levels of expression between GSC-enriched cell cultures and differentiated tumour cell cultures from independent studies using DNA chip microarray technologies. We finally studied the protein expression of the marker we considered the most specific by immunohistochemistry and semi-quantitative analysis on a retrospective series of 18 GBMs. Of the selected studies, 32 genes were retained. Among them, eight genes were identified to be overexpressed in GSC-enriched cultures compared to differentiated tumour cell cultures. Finally, among the eight genes, oligodendrocyte lineage transcription factor 2 (OLIG2) was characterised by the most different expression level in the "GSC model" compared to the "differentiated tumour cells model". Our approach suggests that OLIG2 is the most specific GSC marker; additional investigations with careful considerations about methodology and strategies of validation are, however, mandatory.

Galectin-3 in cancer

Galectin-3 (Gal-3) plays important roles in cell proliferation, adhesion, differentiation, angiogenesis and apoptosis in normal and pathologic tissues. Accumulated evidences indicate that Gal-3 is closely involved in tumor cell transformation, migration, invasion and metastasis. In this review, the associations of the expression and localization of Gal-3 as well as its potential action mechanism in tumorigenesis in a variety of cancers were summarized and concluded. Gal-3 is gaining its attraction as a potential new biomarker for the diagnosis, treatment and prognosis of certain tumors.

Primary effusion lymphoma: secretome analysis reveals novel candidate biomarkers with potential pathogenetic significance

Primary effusion lymphoma (PEL) is a rare B-cell neoplasm in which tumor cells are consistently infected by Kaposi's sarcoma-associated herpesvirus and usually grow in body cavities without tumor mass formation. To detect new proteins related to pathogenesis, four established cell lines from PEL (CRO-AP2, CRO-AP3, CRO-AP5, and CRO-AP6) were characterized by proteomics analysis of the secretome. The secretomes were analyzed using two complementary mass spectrometry platforms: liquid chromatography-mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight-based approaches. Among 266 proteins identified from the proteomics analysis, 139 were considered as predicted secreted. Twenty proteins were specifically secreted by PEL cell lines after comparison with secretomes of human cell lines representative of diverse solid tumors and leukemias. More important, 27 additional proteins were shared by all CRO-AP PEL cell lines. The presence of these proteins was confirmed by IHC in CRO-AP cell lines and in six other PEL cell lines, four PEL clinical samples, and three extracavitary Kaposi's sarcoma-associated herpesvirus-positive solid lymphomas included for comparative analysis. Functional classification showed that PEL cell secretomes were enriched in proteins specifically involved in inflammation/immune response, growth/cell cycle, and mRNA processing, in addition to structural/matrix proteins and proteins with enzymatic activity.

Very low levels of surface CD45 reflect CLL cell fragility, are inversely correlated with trisomy 12 and are associated with increased treatment-free survival

It has recently been suggested that the percentage of smudge cells on blood smears from patients with chronic lymphocytic leukemia (CLL) could predict overall survival. However, smudge cells are a cytological artifact influenced by multiple physical factors not related to CLL. To identify simple parameters reflecting CLL cell fragility, we studied CD45 expression in a series of 66 patients with Binet stage A CLL. Decreased CD45 expression was specific for CLL cells when compared to 44 patients with a leukemic phase of B-cell non Hodgkin lymphoma and 42 control B-cells. CD45 expression was markedly decreased for all patients with CLL with high percentages of smudge cells. CLL cells with the lowest CD45 expression were the most sensitive to osmotic shock. Very low levels of CD45 expression were significantly associated with lack of CD38 expression, absence of trisomy 12, and with increased treatment free survival time. Altogether, these results demonstrate that low levels of CD45 expression are specific to CLL cells and reflect cell fragility, suggesting that this is an important intrinsic biological feature that determines disease course.

Unraveling galectin-1 as a novel therapeutic target for cancer

Galectins belong to a family of carbohydrate-binding proteins with an affinity for β-galactosides. Galectin-1 is differentially expressed by various normal and pathologic tissues and displays a wide range of biological activities. In oncology, galectin-1 plays a pivotal role in tumor growth and in the multistep process of invasion, angiogenesis, and metastasis. Evidence indicates that galectin-1 exerts a variety of functions at different steps of tumor progression. Moreover, it has been demonstrated that galectin-1 cellular localization and galectin-1 binding partners depend on tumor localization and stage. Recently, galectin-1 overexpression has been extensively documented in several tumor types and/or in the stroma of cancer cells. Its expression is thought to reflect tumor aggressiveness in several tumor types. Galectin-1 has been identified as a promising drug target using synthetic and natural inhibitors. Preclinical data suggest that galectin-1 inhibition may lead to direct antiproliferative effects in cancer cells as well as antiangiogenic effects in tumors. We provide an up-to-date overview of available data on the role of galectin-1 in different molecular and biochemical pathways involved in human malignancies. One of the major challenges faced in targeting galectin-1 is the translation of current knowledge into the design and development of effective galectin-1 inhibitors in cancer therapy.

VEGFR1 and VEGFR2 involvement in extracellular galectin-1- and galectin-3-induced angiogenesis

AIM

Accumulating evidence suggests that extracellular galectin-1 and galectin-3 promote angiogenesis. Increased expression of galectin-1 and/or galectin-3 has been reported to be associated with tumour progression. Thus, it is critical to identify their influence on angiogenesis.

METHODS

We examined the individual and combined effects of galectin-1 and galectin-3 on endothelial cell (EC) growth and tube formation using two EC lines, EA.hy926 and HUVEC. The activation of vascular endothelial growth factor receptors (VEGFR1 and VEGFR2) was determined by ELISA and Western blots. We evaluated the VEGFR1 and VEGFR2 levels in endosomes by proximity ligation assay.

RESULTS

We observed different responses to exogenous galectins depending on the EC line. An enhanced effect on EA.hy926 cell growth and tube formation was observed when both galectins were added together. Focusing on this enhanced effect, we observed that together galectins induced the phosphorylation of both VEGFR1 and VEGFR2, whereas galectin-1 and -3 alone induced VEGFR2 phosphorylation only. In the same way, the addition of a blocking VEGFR1 antibody completely abolished the increase in tube formation induced by the combined addition of both galectins. In contrast, the addition of a blocking VEGFR2 antibody only partially inhibited this effect. Finally, the addition of both galectins induced a decrease in the VEGFR1 and VEGFR2 endocytic pools, with a significantly enhanced effect on the VEGFR1 endocytic pool. These results suggest that the combined action of galectin-1 and galectin-3 has an enhanced effect on angiogenesis via VEGFR1 activation, which could be related to a decrease in receptor endocytosis.

Galectin-3 binds to CD45 on diffuse large B-cell lymphoma cells to regulate susceptibility to cell death

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma and an aggressive malignancy. Galectin-3 (gal-3), the only antiapoptotic member of the galectin family, is overexpressed in DLBCL. While gal-3 can localize to intracellular sites, gal-3 is secreted by DLBCL cells and binds back to the cell surface in a carbohydrate-dependent manner. The major counterreceptor for gal-3 on DLBCL cells was identified as the transmembrane tyrosine phosphatase CD45. Removal of cell-surface gal-3 from CD45 with the polyvalent glycan inhibitor GCS-100 rendered DLBCL cells susceptible to chemotherapeutic agents. Binding of gal-3 to CD45 modulated tyrosine phosphatase activity; removal of endogenous cell-surface gal-3 from CD45 with GCS-100 increased phosphatase activity, while addition of exogenous gal-3 reduced phosphatase activity. Moreover, the increased susceptibility of DLBCL cells to chemotherapeutic agents after removal of gal-3 by GCS-100 required CD45 phosphatase activity. Gal-3 binding to a subset of highly glycosylated CD45 glycoforms was regulated by the C2GnT-1 glycosyltransferase, indicating that specific glycosylation of CD45 is important for regulation of gal-3-mediated signaling. These data identify a novel role for cell-surface gal-3 and CD45 in DLBCL survival and suggest novel therapeutic targets to sensitize DLBCL cells to death.

A simplified approach for the molecular classification of glioblastomas

Glioblastoma (GBM) is the most common malignant primary brain tumors in adults and exhibit striking aggressiveness. Although GBM constitute a single histological entity, they exhibit considerable variability in biological behavior, resulting in significant differences in terms of prognosis and response to treatment. In an attempt to better understand the biology of GBM, many groups have performed high-scale profiling studies based on gene or protein expression. These studies have revealed the existence of several GBM subtypes. Although there remains to be a clear consensus, two to four major subtypes have been identified. Interestingly, these different subtypes are associated with both differential prognoses and responses to therapy. In the present study, we investigated an alternative immunohistochemistry (IHC)-based approach to achieve a molecular classification for GBM. For this purpose, a cohort of 100 surgical GBM samples was retrospectively evaluated by immunohistochemical analysis of EGFR, PDGFRA and p53. The quantitative analysis of these immunostainings allowed us to identify the following two GBM subtypes: the “Classical-like” (CL) subtype, characterized by EGFR-positive and p53- and PDGFRA-negative staining and the “Proneural-like” (PNL) subtype, characterized by p53- and/or PDGFRA-positive staining. This classification represents an independent prognostic factor in terms of overall survival compared to age, extent of resection and adjuvant treatment, with a significantly longer survival associated with the PNL subtype. Moreover, these two GBM subtypes exhibited different responses to chemotherapy. The addition of temozolomide to conventional radiotherapy significantly improved the survival of patients belonging to the CL subtype, but it did not affect the survival of patients belonging to the PNL subtype. We have thus shown that it is possible to differentiate between different clinically relevant subtypes of GBM by using IHC-based profiling, a method that is advantageous in its ease of daily implementation and in large-scale clinical application.

Galectin-1, -3, -7 expressions in congenital and acquired pediatric cholesteatomas compared to external auditory canal skin

OBJECTIVES

There is a classical distinction based on clinical criteria between acquired and congenital cholesteatomas. To determine if these two types of lesions show different immunohistochemical features, we have studied the expression patterns of three distinctive galectins (animal lectins implied especially in cellular proliferation and apoptosis) in both types of cholesteatomas and compared it to their expression patterns in external auditory canal skin.

METHODS

Our study is based on nine acquired and eight congenital cholesteatomas, obtained from children during ear surgery. Six specimens of normal adult auditory meatal skin served as control. Specimens were analyzed by immunohistochemistry using monoclonal antibodies with galectin-1 and galectin-3, and a polyclonal antibody with galectin-7.

RESULTS

We did not observe any differences in the galectin distribution pattern between congenital and acquired pediatric cholesteatomas. Compared to the control group, cholesteatomas present some particular features. There was no expression of galectin-1 and a lower expression of galectin-3 in the epithelium. Furthermore, we observed a preferentially nuclear distribution of galectin-7 in cholesteatomas, whereas it is essentially cytoplasmic in the control group.

CONCLUSION

The data reported in this study suggest, on the basis of a lesser marked galectin-3 in cholesteatomas epithelium compared with an external auditory canal skin, that an immature keratinocytes population is at the origin of these lesions and that galectin-3 and galectin-7 play a part in the capacity as apoptosis modulators. Our study does not establish a difference in the galectin expressions of congenital and acquired cholesteatomas, but it constitutes however an additional argument in favor of the "undifferentiated" origin of keratinocytes in cholesteatomas.

TIMP-4 and CD63: new prognostic biomarkers in human astrocytomas

Based on the molecular profiling of astrocytomas, we previously identified a series of genes involved in astrocytoma invasion. Of these, tissue inhibitor of metalloproteinase-4 (TIMP-4) was found to be overexpressed in pilocytic astrocytomas relative to diffuse astrocytomas of any histological grade. Although some data suggest that TIMP-4 may be an anti-tumoral actor in astrocytomas, recent findings challenge this concept. The present study aims to investigate the diagnostic and prognostic values of TIMP-4 and its putative partner CD63 in human astrocytomas. Tissue microarray and image analysis were first carried out to quantitatively analyze the immunohistochemical expression of these proteins in 471 gliomas including 354 astrocytomas. Pathological semi-quantitative scores of both markers' expression were then established and correlated to astrocytoma diagnosis and patient prognosis. TIMP-4 and CD63 expressions were both overexpressed in astrocytomas compared with oligodendrogliomas (P<0.001) and in pilocytic astrocytomas compared with grade II diffuse astrocytomas (P<0.001). In glioblastomas, high TIMP-4/CD63 co-expression scores were identified as independent prognostic factors associated with progression and shorter survival. In conclusion, this work provides the first evidence of a TIMP-4/CD63 association in astrocytoma tumor cells. It identifies TIMP-4 and CD63 as markers of the astrocytic phenotype in patients with gliomas. In addition, this work highlights the contribution of high TIMP-4/CD63 co-expression to the adverse outcomes of patients with glioblastomas.

Requirements for the valid quantification of immunostains on tissue microarray materials using image analysis

Antibody-based proteomics applied to tissue microarray (TMA) technology provides a very efficient means of visualizing and locating antigen expression in large collections of normal and pathological tissue samples. To characterize antigen expression on TMAs, the use of image analysis methods avoids the effects of human subjectivity evidenced in manual microscopical analysis. Thus, these methods have the potential to significantly enhance both precision and reproducibility. Although some commercial systems include tools for the quantitative evaluation of immunohistochemistry-stained images, there exists no clear agreement on best practices to allow for correct and reproducible quantification results. Our study focuses on practical aspects regarding (i) image acquisition (ii) segmentation of staining and counterstaining areas and (iii) extraction of quantitative features. We illustrate our findings using a commercial system to quantify different immunohistochemistry markers targeting proteins with different expression patterns (cytoplasmic, nuclear or membranous) in colon cancer or brain tumor TMAs. Our investigations led us to identify several steps that we consider essential for standardizing computer-assisted immunostaining quantification experiments. In addition, we propose a data normalization process based on reference materials to be able to compare measurements between studies involving different TMAs. In conclusion, we recommend certain critical prerequisites that commercial or in-house systems should satisfy in order to permit valid immunostaining quantification.

Duodenal intraepithelial lymphocytes of children with cow milk allergy preferentially bind the glycan-binding protein galectin-3

A breakdown in intestinal homeostasis results in inflammatory bowel diseases including coeliac disease and allergy. Galectins, evolutionarily conserved beta-galactoside-binding proteins, can modulate immune-epithelial cell interactions by influencing immune cell fate and cytokine secretion. In this study we investigated the glycosylation signature, as well as the regulated expression of galectin-1 and -3 in human duodenal samples of allergic and non-allergic children. Whereas galectin-1 was predominantly localized in the epithelial compartment (epithelial cells and intraepithelial lymphocytes) and the underlying lamina propria (T cells, macrophages and plasma cells), galectin-3 was mainly expressed by crypt epithelial cells and macrophages in the lamina propria. Remarkably, expression of these galectins was not significantly altered in allergic versus non-allergic patients. Investigation of the glycophenotype of the duodenal inflammatory microenvironment revealed substantial alpha2-6-linked sialic acid bound to galactose in lamina propria plasma cells, macrophages and intraepithelial lymphocytes and significant levels of asialo core 1 O-glycans in CD68+ macrophages and enterocytes. Galectin-1 preferentially bound to neutrophils, plasma cells and enterocytes, while galectin-3 binding sites were mainly distributed on macrophages and intraepithelial lymphocytes. Notably, galectin-3, but not galectin-1 binding, was substantially increased in intraepithelial gut lymphocytes of allergic patients compared to non-allergic subjects, suggesting a potential role of galectin-3-glycan interactions in shaping epithelial-immune cell connections during allergic inflammatory processes.

Patterns of interstitial inflammation during the evolution of renal injury in experimental aristolochic acid nephropathy

BACKGROUND

Interstitial inflammation is a prominent feature associated with the severity of renal injury and progressive kidney failure. We utilized an animal model of aristolochic acid (AA)-induced nephropathy (AAN) to assess patterns of infiltration and inflammation during the evolution of tubulointerstitial damage and to relate them to the development of fibrosis.

METHODS

Male Wistar rats receiving sc daily AA or vehicle were sacrificed between Days 1 and 35. Infiltrating mononuclear cells were characterized by immunohistochemistry. The kidney infiltrating T lymphocytes were phenotyped by flow cytometry. Urinary levels of Th-1/ Th-2 cytokines, of monocyte chemoattractant protein-1 and of active transforming growth factor-beta (TGF-beta) were measured. Tissue expression of phosphorylated smad 2/3 protein was used to examine the TGF-beta signalling pathway.

RESULTS

In AA rats, monocytes/macrophages and T lymphocytes predominantly infiltrated areas of necrotic proximal tubular cells. The coexpressions of ED1 and/or Ki-67/MHCII by infiltrating cells reflected monocyte/macrophage proliferation and their activation, respectively. The accumulation of cytotoxic T lymphocytes was attested by severe signs of CD8+ cell tubulitis. The CD8/E-cadherin costaining confirmed intrarenal homing of CD8+CD103+ cells. Urinary levels of proinflammatory cytokines and of active TGF-beta significantly increased at Days 10 and 35. An early and persistent nuclear overexpression of phosphorylated smad 2/3 protein was detected in tubular and interstitial compartments.

CONCLUSION

An early and massive interstitial inflammation characterized by activated monocytes/macrophages and cytotoxic CD8+CD103+ T lymphocytes is demonstrated for the first time during the progression of experimental AAN. The involvement in an interstitial fibrosis onset of active TGF-beta is highly suggested, at least via the psmad 2/3 intracellular signalling pathway.

Expression of Co-stimulatory molecules on langerhans cells in lesional epidermis of human atopic dermatitis

Langerhans cells (LC) are immature dendritic cells (DC) present in the skin epithelium. To understand the molecular and cellular mechanisms governing the inflammatory reaction in atopic dermatitis (AD), the expression of the LC specific marker CD1a, a member of major histocompatibility (MHC)-like glycoproteins, and the co-stimulatory molecules CD80 and CD86, expressed on functionally mature dendritic cells, were counted in lesional biopsies and normal epidermis by an immunohistochemical method. CD1a specific staining was observed in both normal and AD lesion specimens. CD80 and CD86 positive cells with morphological characteristics of the LC were found in lesional AD epidermis, suggesting a high level of functional maturity of these cells and their involvement in chronic inflammatory disease.

Aristolochic acid induces proximal tubule apoptosis and epithelial to mesenchymal transformation

Aristolochic acid contamination in herbal remedies leads to interstitial fibrosis, tubular atrophy, and renal failure in humans. To study the cellular mechanisms contributing to the pathophysiology of this renal disease, we studied Wistar rats treated with aristolochic acid and measured tubular and interstitial cell proliferation, epithelial/mesenchymal cell marker expression, tubular membrane integrity, myofibroblast accumulation, oxidative stress, mitochondrial damage, tubular apoptosis, and fibrosis. Oxidative stress, a loss of cadherin concomitant with vimentin expression, basement membrane denudation with active caspase-3 expression, and mitochondrial injury within tubular cells were evident within 5 days of administration of the toxin. During the chronic phase, interstitial mesenchymal cells accumulated in areas of collagen deposits. Impaired regeneration and apoptosis of proximal tubular cells resulted in tubule atrophy with a near absence of dedifferentiated cell transmembrane migration. We suggest that resident fibroblast activation plays a critical role in the process of renal fibrosis during aristolochic acid toxicity.

Galectin-1 mediated suppression of Epstein-Barr virus specific T-cell immunity in classic Hodgkin lymphoma

In Hodgkin lymphoma (HL), the malignant Hodgkin Reed-Sternberg cells interact with the host microenvironment to create an immunosuppressive network that protects the lymphoma from immune attack. These mechanisms are not fully understood. We examined the role of the immunomodulatory protein galectin-1 (Gal-1) on Epstein-Barr virus-specific CD8(+) T cell responses in HL. Initial studies indicated Gal-1 expression in all in vitro established Hodgkin Reed-Sternberg cell lines. In situ analysis revealed Gal-1 expression in 26 of 42 classic HL, whereas Gal-1 was uniformly negative in nodular lymphocyte predominant HL. Gal-1(hi) expression was associated with male gender, older patients, reduced CD8(+) T cell infiltration at the tumor site, and most importantly, an impaired latent membrane protein 1 and 2-specific CD8(+) T-cell responses. In vitro exposure to recombinant Gal-1 inhibited proliferation and interferon-gamma expression by Epstein-Barr virus-specific T cells. These observations provide an important link between the Gal-1-mediated immunomodulatory networks and loss of antigen-specific T-cell function in classic HL.

IL-1beta induces alkaline phosphatase in human phagocytes

BACKGROUND

Alkaline phosphatase (ALPase) is found in blood plasma or serum and leukocytes and regulates intercellular processes, maintaining phosphoryl metabolites in a steady state, as well as synthesizing and hydrolyzing phosphate esters on membranes. ALPase supervises the active transport of inorganic phosphates, fats, proteins, carbohydrates and the sodium/potassium pump mechanisms. The formed elements of blood such as polymorphonuclear (PMNs) leucocytes, macrophages (MP) and some lymphocytes are high in ALPase concentrations.

METHODS

In this study we have tested whether the interleukin-1 receptor antagonist (IL-lra) could influence ALPase generation in IL-1beta or lipopolysaccharide (LPS)-stimulated neutrophils and MP. Human neutrophils were isolated from heparin-anticoagulated blood drawn from healthy individuals by centrifugation in a two-step gradient, Ficoll-Hypaque. ALPase activity was assessed spectrophotometrically in test tubes containing isolated neutrophils and adherence PBMCs treated with LPS, IL-1beta and IL-1ra, alone or in combination.

RESULTS

IL-lbeta or LPS enhanced ALPase in both PMNs and MP, whereas IL-1ra could not inhibit ALPase activity. We performed time course experiments at 0 min, 5 min, 1 h, 24 h, and 43 h (LPS 20 microg/mL, IL-1beta 10 ng/mL). No significant increase in ALPase activity was seen until 1 h; however, there was a rapid rise over the next few hours. In another set of experiments using IL-1ra (500 ng/mL), there was no difference between treated cells and control cells. The combination of IL-1beta plus IL-1ra did not reduce the ability of IL-1beta to induce ALPase activity.

CONCLUSIONS

These data suggest that IL-1beta stimulates ALPase through other mechanisms than the release of arachidonic acid products, which are inhibited by IL-lra.

Microarray-Based Identification of Tenascin C and Tenascin XB, Genes Possibly Involved in Tumorigenesis Associated with Neurofibromatosis Type 1

PURPOSE

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a complex variety of clinical manifestations. The hallmark of NF1 is the onset of heterogeneous (dermal or plexiform) benign neurofibromas. Plexiform neurofibromas can give rise to malignant peripheral nerve sheath tumors, which are resistant to conventional therapies.

EXPERIMENTAL DESIGN

To identify new signaling pathways involved in the malignant transformation of plexiform neurofibromas, we applied a 22,000-oligonucleotide microarray approach to a series of plexiform neurofibromas and malignant peripheral nerve sheath tumors. Changes in the expression of selected genes were then confirmed by real-time quantitative reverse transcription-PCR.

RESULTS

We identified two tenascin gene family members that were significantly deregulated in both human NF1-associated tumors and NF1-deficient primary cells: Tenascin C (TNC) was up-regulated whereas tenascin XB (TNXB) was down-regulated during tumor progression. TNC activation is mainly due to the up-regulation of large TNC splice variants. Immunohistochemical studies showed that TNC transcripts are translated into TNC protein in TNC-overexpressing tumors. Aberrant transcriptional activation of TNC seems to be principally mediated by activator protein transcription factor complexes.

CONCLUSION

TNXB and TNC may be involved in the malignant transformation of plexiform neurofibromas. Anti-TNC antibodies, already used successfully in clinical trials to treat malignant human gliomas, may be an appropriate new therapeutic strategy for NF1.

Galectin-1: a small protein with major functions

Galectins are a family of carbohydrate-binding proteins with an affinity for beta-galactosides. Galectin-1 (Gal-1) is differentially expressed by various normal and pathological tissues and appears to be functionally polyvalent, with a wide range of biological activity. The intracellular and extracellular activity of Gal-1 has been described. Evidence points to Gal-1 and its ligands as one of the master regulators of such immune responses as T-cell homeostasis and survival, T-cell immune disorders, inflammation and allergies as well as host-pathogen interactions. Gal-1 expression or overexpression in tumors and/or the tissue surrounding them must be considered as a sign of the malignant tumor progression that is often related to the long-range dissemination of tumoral cells (metastasis), to their dissemination into the surrounding normal tissue, and to tumor immune-escape. Gal-1 in its oxidized form plays a number of important roles in the regeneration of the central nervous system after injury. The targeted overexpression (or delivery) of Gal-1 should be considered as a method of choice for the treatment of some kinds of inflammation-related diseases, neurodegenerative pathologies and muscular dystrophies. In contrast, the targeted inhibition of Gal-1 expression is what should be developed for therapeutic applications against cancer progression. Gal-1 is thus a promising molecular target for the development of new and original therapeutic tools.