Roles of galectin-7 and S100A9 in cervical squamous carcinoma: Clinicopathological and in vitro evidence

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-7 promotes cisplatin efficacy by facilitating apoptosis and G3BP1 degradation in cervical cancer

The emergence of chemoresistance in cervical cancer is extremely challenging in chemotherapy. Oxidative stress has emerged as the regulatory factor in drug resistance, but the detailed mechanism is still unknown. Stress granules, are membrane-less ribonucleoprotein-based condensates, could enhance chemoresistance by sequestering proapoptotic proteins inhibition of cell death upon exposure to drug-induced oxidative stress. Galectin-7, a member of galectin family, exerts varied roles in tumor repression or progression in different cancers. However, its role in cervical cancer has not been sufficiently studied. Here, we found that galectin-7 promotes cisplatin (CDDP) induced apoptosis and associates with stress granule-nucleating protein G3BP1 degradation. With the treatment of cisplatin, galectin-7 could enhance apoptosis by upregulating cleaved-PARP1 and the generation of reactive oxygen species (ROS), promoting mitochondrial fission, and reducing mitochondrial membrane potential (MMP). Furthermore, galectin-7 also reduces resistance by facilitating cisplatin-induced stress granules clearance through galectin-7/RACK1/G3BP1 axis. All these data suggested that galectin-7 promotes cisplatin sensitivity, and it would be potential target for potentiating efficacy in cervical cancer chemotherapy.

Galectin-7 reprograms skin carcinogenesis by fostering innate immune evasive programs

Non-melanoma skin cancer (NMSC) has risen dramatically as a result of chronic exposure to sunlight ultraviolet (UV) radiation, climatic changes and clinical conditions associated with immunosuppression. In spite of considerable progress, our understanding of the mechanisms that control NMSC development and their associated molecular and immunological landscapes is still limited. Here we demonstrated a critical role for galectin-7 (Gal-7), a β-galactoside-binding protein preferentially expressed in skin tissue, during NMSC development. Transgenic mice (Tg46) overexpressing Gal-7 in keratinocytes showed higher number of papillomas compared to WT mice or mice lacking Gal-7 (Lgals7^-/-) when subjected to a skin carcinogenesis protocol, in which tumor initiator 7,12-dimethylbenz[a]anthracene (DMBA) and tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) were sequentially administered. RNAseq analysis of Tg46 tumor lesions revealed a unique profile compatible with cells of the myelomonocytic lineage infiltrating these tumors, an effect that was substantiated by a higher number of CD11b⁺Gr1⁺ cells in tumor-draining lymph nodes. Heightened c-Met activation and Cxcl-1 expression in Tg46 lesions suggested a contribution of this pathway to the recruitment of these cells. Remarkably, Gal-7 bound to the surface of CD11b⁺Ly6C^hiLy6G^lo monocytic myeloid cells and enhanced their immunosuppressive activity, as evidenced by increased IL-10 and TGF-β₁ secretion, and higher T-cell inhibitory activity. In vivo, carcinogen-treated Lgals7^-/- animals adoptively transferred with Gal-7-conditioned monocytic myeloid cells developed higher number of papillomas, whereas depletion of these cells in Tg46-treated mice led to reduction in the number of tumors. Finally, human NMSC biopsies showed increased LGALS7 mRNA and Gal-7 protein expression and displayed transcriptional profiles associated with myeloid programs, accompanied by elevated CXCL1 expression and c-Met activation. Thus, Gal-7 emerges as a critical mediator of skin carcinogenesis and a potential therapeutic target in human NMSC.

Identification of Galectin-7 as a crucial metastatic enhancer of squamous cell carcinoma associated with immunosuppression

Metastasis predicts poor prognosis in cancer patients. It has been recognized that specific tumor microenvironment defines cancer cell metastasis, whereas the underlying mechanisms remain elusive. Here we show that Galectin-7 is a crucial mediator of metastasis associated with immunosuppression. In a syngeneic mouse squamous cell carcinoma (SCC) model of NR-S1M cells, we isolated metastasized NR-S1M cells from lymph nodes in tumor-bearing mice and established metastatic NR-S1M cells in in vitro culture. RNA-seq analysis revealed that interferon gene signature was markedly downregulated in metastatic NR-S1M cells compared with parental cells, and in vivo NR-S1M tumors heterogeneously developed focal immunosuppressive areas featured by deficiency of anti-tumor immune cells. Spatial transcriptome analysis (Visium) for the NR-S1M tumors revealed that various pro-metastatic genes were significantly upregulated in immunosuppressive areas when compared to immunocompetent areas. Notably, Galectin-7 was identified as a novel metastasis-driving factor. Galectin-7 expression was induced during tumorigenesis particularly in the microenvironment of immunosuppression, and extracellularly released at later stage of tumor progression. Deletion of Galectin-7 in NR-S1M cells significantly suppressed lymph node and lung metastasis without affecting primary tumor growth. Therefore, Galectin-7 is a crucial mediator of tumor metastasis of SCC, which is educated in the immune-suppressed tumor areas, and may be a potential target of cancer immunotherapy.

Binding of Glycerol to Human Galectin-7 Expands Stability and Modulates Its Functions

Glycerol is seen in biological systems as an intermediate in lipid metabolism. In recent years, glycerol has been reported to act as a chemical chaperone to correct the conformation of proteins. Here, we investigate the role of glycerol in galectin-7 (Gal-7). The thermal shift and CD assays showed that the thermal stability of Gal-7 increased with glycerol concentration but with little secondary structure changes induced by glycerol. In addition, glycerol can inhibit Gal-7-mediated erythrocyte agglutination. We also solved the crystal structures of human Gal-7 in complex with glycerol in two different conditions. Glycerol binds at the carbohydrate-recognition binding sites of Gal-7, which indicates glycerol as a small ligand for Gal-7. Surprisingly, glycerol can bind a new pocket near the N-terminus of Gal-7, which can greatly reduce the flexibility and improve the stability of this region. Moreover, overexpression of Gal-7 decreased the intracellular triglyceride levels and increased mRNA expression of aquaporin-3 (AQP-3) when HeLa cells were incubated with glycerol. These findings indicate that Gal-7 might regulate glycerol metabolism. Overall, our results on human Gal-7 raise the perspective to systematically explore this so far unrecognized phenomenon for Gal-7 in glycerol metabolism.

Functions and Inhibition of Galectin-7, an Emerging Target in Cellular Pathophysiology

Galectin-7 is a soluble unglycosylated lectin that is able to bind specifically to β-galactosides. It has been described to be involved in apoptosis, proliferation and differentiation, but also in cell adhesion and migration. Several disorders and diseases are discussed by covering the aforementioned biological processes. Structural features of galectin-7 are discussed as well as targeting the protein intracellularly or extracellularly. The exact molecular mechanisms that lie behind many biological processes involving galectin-7 are not known. It is therefore useful to come up with chemical probes or tools in order to obtain knowledge of the physiological processes. The objective of this review is to summarize the roles and functions of galectin-7 in the human body, providing reasons why it is necessary to design inhibitors for galectin-7, to give the reader structural insights and describe its current inhibitors.

Quantitative proteomics identifies biomarkers to distinguish pulmonary from head and neck squamous cell carcinomas by immunohistochemistry

The differentiation between a pulmonary metastasis and a newly developed squamous cell carcinoma of the lung in patients with prior head and neck squamous cell carcinoma (HNSCC) is difficult due to a lack of biomarkers but is crucially important for the prognosis and therapy of the affected patient. By using high‐resolution mass spectrometry in combination with stable isotope labelling by amino acids in cell culture, we identified 379 proteins that are differentially expressed in squamous cell carcinomas of the lung and the head and neck. Of those, CAV1, CAV2, LGALS1, LGALS7, CK19, and UGDH were tested by immunohistochemistry on 194 tissue samples (98 lung and 96 HNSCCs). The combination of CAV1 and LGALS7 was able to distinguish the origin of the squamous cell carcinoma with high accuracy (area under the curve 0.876). This biomarker panel was tested on a cohort of 12 clinically classified lung tumours of unknown origin after HNSCC. Nine of those tumours were immunohistochemically classifiable.

Towards a Better Understanding of the Relationships between Galectin-7, p53 and MMP-9 during Cancer Progression

It has been almost 25 years since the discovery of galectin-7. This member of the galectin family has attracted interest from many working in the cancer field given its highly restricted expression profile in epithelial cells and the fact that cancers of epithelial origin (carcinoma) are among the most frequent and deadly cancer subtypes. Initially described as a p53-induced gene and associated with apoptosis, galectin-7 is now recognized as having a protumorigenic role in many cancer types. Several studies have indeed shown that galectin-7 is associated with aggressive behavior of cancer cells and induces expression of MMP-9, a member of the matrix metalloproteinases (MMP) family known to confer invasive behavior to cancer cells. It is therefore not surprising that many studies have examined its relationships with p53 and MMP-9. However, the relationships between galectin-7 and p53 and MMP-9 are not always clear. This is largely because p53 is often mutated in cancer cells and such mutations drastically change its functions and, consequently, its association with galectin-7. In this review, we discuss the functional relationships between galectin-7, p53 and MMP-9 and reconcile some apparently contradictory observations. A better understanding of these relationships will help to develop a working hypothesis and model that will provide the basis for further research in the hope of establishing a new paradigm for tackling the role of galectin-7 in cancer.

Roles of S100 family members in drug resistance in tumors: Status and prospects

Chemotherapy and targeted therapy can significantly improve survival rates in cancer, but multiple drug resistance (MDR) limits the efficacy of these approaches. Understanding the molecular mechanisms underlying MDR is crucial for improving drug efficacy and clinical outcomes of patients with cancer. S100 proteins belong to a family of calcium-binding proteins and have various functions in tumor development. Increasing evidence demonstrates that the dysregulation of various S100 proteins contributes to the development of drug resistance in tumors, providing a basis for the development of predictive and prognostic biomarkers in cancer. Therefore, a combination of biological inhibitors or sensitizers of dysregulated S100 proteins could enhance therapeutic responses. In this review, we provide a detailed overview of the mechanisms by which S100 family members influence resistance of tumors to cancer treatment, with a focus on the development of effective strategies for overcoming MDR.

Prognostic Role of S100A8 and S100A9 Protein Expressions in Non-small Cell Carcinoma of the Lung

Background

S100A8 and S100A9 have been gaining recognition for modulating tumor growthand metastasis. This study aimed at evaluating the clinical significance of S100A8 and S100A9 innon-small cell lung cancer (NSCLC).

Methods

We analyzed the relationship between S100A8and S100A9 expressions, clinicopathological characteristics, and prognostic significance in tumorcells and peritumoral inflammatory cells.

Results

The positive staining of S100A8 in tumorcells was significantly increased in male (p < .001), smoker (p = .034), surgical method other thanlobectomy (p = .024), squamous cell carcinoma (SQCC) (p < .001) and higher TNM stage (p = .022)compared with female, non-smoker, lobectomy, adenocarcinoma (ADC), and lower stage. Theproportion of tumor cells stained for S100A8 was related to histologic type (p < .001) and patientsex (p = .027). The proportion of inflammatory cells stained for S100A8 was correlated with patientage (p = .022), whereas the proportion of inflammatory cells stained for S100A9 was correlatedwith patient sex (p < .001) and smoking history (p = .031). Moreover, positive staining in tumorcells, more than 50% of the tumor cells stained and less than 30% of the inflammatory cellsstained for S100A8 and S100A9 suggested a tendency towards increased survivability in SQCCbut towards decreased survivability in ADC.

Conclusions

S100A8 and S100A9 expressions might be potential prognostic markers in patients with NSCLC.

The Role of Galectins in Tumor Progression, Treatment and Prognosis of Gynecological Cancers

Galectins are the member of soluble proteins that bind with β-galactoside containing glycans. These proteins have been considered to be associated in various important events such as different types of cancers. It has been found that galectins could contribute to neoplastic transformation or regulate cell growth, cell apoptosis, and immune cells, causing tumor invasion, progression, metastasis and angiogenesis. Somehow, galectins are also found to exert a protective effect on cancer in a tissue-dependent way. These glycans binding proteins have been shown to be involved in the regulation of different tumor suppressor genes and oncogenes with their possible roles in human cancers. Objective of the current review is to summarize the role of galectin-1, -3 -7, and -9 in tumorigenesis of gynecological cancers. Galectin protein may be a potential therapeutic target in gynecological malignancies due to reported radio- and chemo- sensitivities, immunotherapeutic, anti-angiogenic and anti-proliferative activities. This review considers the evidence for the future research that how galectins may be important in the progression and treatment of gynecological cancers along with its potent use as a novel prognostic marker.

S100A9 regulates cisplatin chemosensitivity of squamous cervical cancer cells and related mechanism

Objective

Our previous research has shown that the expression of S100 calcium-binding protein A9 (S100A9) in tumor cells was associated with neoadjuvant chemotherapy sensitivity in cervical squamous cell carcinoma. In the present study, we altered the expression of S100A9 through infecting lentivirus, investigated its effect on the chemosensitivity to cisplatin of cervical cancer cells and then made a primary exploration of the involved mechanism.

Materials and methods

Lentivirus was employed to upregulate and downregulate S100A9 expression in SiHa cells. The protein expression level of apoptotic-related proteins Bcl-2 and Bax, drug resistance-related proteins multiple drug resistance protein 1 (MRP1), P glycoprotein (P-gp), glutathione-S-transferase-π (GST-π), lung resistance-related protein (LRP), and FOXO1 signaling pathway related proteins was detected by Western blot. The CCK-8 assay was used to examine chemosensitivity to cisplatin, and the proportion of apoptosis cells was analyzed by the flow cytometry.

Results

S100A9 overexpression could obviously increase the IC50 value of SiHa cells to cisplatin and decrease the apoptosis rate induced by cisplatin. Downregulation of S100A9 led to the opposite results. In S100A9 overexpression SiHa cells, the expression level of Bcl-2, LRP, GST-π, p-AKT, p-ERK, p-FOXO1, and Nanog was significantly increased, while FOXO1 expression was decreased. The opposite results were observed in S100A9 knockdown SiHa cells.

Conclusion

Downregulation of S100A9 could significantly increase apoptosis rate, resulting in enhancing sensitivity of SiHa cells to cisplatin, which may be related to Bcl-2, GST-π, and LRP protein and by altering the AKT/ERK-FOXO1-Nanog signaling pathway.

HSP40 co-chaperone protein Tid1 suppresses metastasis of head and neck cancer by inhibiting Galectin-7-TCF3-MMP9 axis signaling

Human tumorous imaginal disc (Tid1), a DnaJ co-chaperone protein, is classified as a tumor suppressor. Previously, we demonstrated that Tid1 reduces head and neck squamous cell carcinoma (HNSCC) malignancy. However, the molecular details of Tid1-mediated anti-metastasis remain elusive.

Methods: We used affinity chromatography and systemic mass spectrometry to identify Tid1-interacting client proteins. Immunohistochemical staining of Tid1 in HNSCC patient tissues was examined to evaluate the association between the expression profile of Tid1-interacting client proteins with pathologic features and prognosis. The roles of Tid1-interacting client proteins in metastasis were validated both in vitro and in vivo. The interacting partner and downstream target of Tid1-interacting client protein were determined.

Results: Herein, we first revealed that Galectin-7 was one of the Tid1-interacting client proteins. An inverse association of protein expression profile between Tid1 and Galectin-7 was determined in HNSCC patients. Low Tid1 and high Galectin-7 expression predicted poor overall survival in HNSCC. Furthermore, Tid1 abolished the nuclear translocation of Galectin-7 and suppressed Galectin-7-induced tumorigenesis and metastasis. Keratinocyte-specific Tid1-deficient mice with 4-nitroquinoline-1-oxide (4NQO) treatment exhibited increased protein levels of Galectin-7 and had a poor survival rate. Tid1 interacted with Galectin-7 through its N-linked glycosylation to promote Tid1-mediated ubiquitination and proteasomal degradation of Galectin-7. Additionally, Galectin-7 played a critical role in promoting tumorigenesis and metastatic progression by enhancing the transcriptional activity of TCF3 transcription factor through elevating MMP-9 expression.

Conclusions: Overall, future treatments through activating Tid1 expression or inversely repressing the oncogenic function of Galectin-7 may exhibit great potential in targeting HNSCC progression.

The role of calgranulin B gene on the biological behavior of squamous cervical cancer in vitro and in vivo

Objective

The objective of the study was to explore the role of calgranulin B gene on the biological behavior of squamous cervical cancer.

Methods

Differential transcription in calgranulin B gene between human papillomavirus (HPV)-positive and negative cervical cancer groups was identified, and the relationship between calgranulin B gene and matrix metalloproteinase (MMP) genes were explored using The Cancer Genome Atlas database. Subsequently, the role of calgranulin B on the cell proliferation, apoptosis, invasion and migration was investigated, through overexpression and/or underexpression of calgranulin B in cervical cancer cells. In addition, the effect of calgranulin B on the growth of the cervical cancer was studied via constructing xenograft model in BALB/c nude mice that either overexpressed or underexpressed calgranulin B.

Results

Calgranulin B gene transcription in cervical cancer was highly correlated with the high-risk HPV-16 and HPV-45. In addition, overexpression of calgranulin B increased cell proliferation, invasion and migration, whereas it did not significantly affect cell apoptosis. This effect was also confirmed by calgranulin B knockdown assay. Additionally, we found that the transcription of calgranulin B gene was negatively correlated with MMP15 and MMP24 genes, but positively associated with MMP25 genes in cervical cancer. Furthermore, calgranulin B significantly promoted the growth of cervical cancer in vivo.

Conclusion

Calgranulin B promotes cell proliferation, migration and invasion of squamous cervical cancer, possibly via regulation of MMPs. Whether there are synergistic actions between calgranulin B and HPV-16/HPV-45 infection on the squamous cervical carcinogenesis or progression need further study.

High expression of galectin-7 associates with poor overall survival in patients with non-metastatic clear-cell renal cell carcinoma

Background

Galectin-7, has a controversial role in tumor progression, can either suppress tumor growth or induce chemoresistance depends on different tumor histology types. The aim was to appraise Galectin-7 expression on the overall survival (OS) of patients with non-metastatic clear cell renal cell carcinoma (ccRCC) following surgery.

Results

High galectin-7 expression was specifically correlated with necrosis (P = 0.015). Multivariate analysis confirmed galectin-7 as an independent prognosticator for OS (P = 0.005). High galectin-7 expression suggested poor OS (P < 0.001), particularly with UISS intermediate and high score groups. Notably, the predictive accuracy of the traditional prognostic scores was improved when combined with galectin-7 expression.

Materials and Methods

We retrospectively enrolled 416 patients who underwent nephrectomy at a single institute between 2008 and 2009 and detected their intratumor galectin-7 expression by immunohistochemistry. Kaplan-Meier method was conducted to plot survival curves and multivariate cox regression analysis for potential independent prognostic factors on OS. A nomogram was constructed with concordance index (C-index) and Akaike's Information Criteria (AIC) to appraise prognostic accuracy of different models.

Conclusions

High galectin-7 expression is an independent adverse predictor for survival. Evaluation of galectin-7 could help guide postsurgical management for non-metastatic ccRCC patients.

Galectin Targeted Therapy in Oncology: Current Knowledge and Perspectives

The incidence and mortality of cancer have increased over the past decades. Significant progress has been made in understanding the underpinnings of this disease and developing therapies. Despite this, cancer still remains a major therapeutic challenge. Current therapeutic research has targeted several aspects of the disease such as cancer development, growth, angiogenesis and metastases. Many molecular and cellular mechanisms remain unknown and current therapies have so far failed to meet their intended potential. Recent studies show that glycans, especially oligosaccharide chains, may play a role in carcinogenesis as recognition patterns for galectins. Galectins are members of the lectin family, which show high affinity for β-galactosides. The galectin–glycan conjugate plays a fundamental role in metastasis, angiogenesis, tumor immunity, proliferation and apoptosis. Galectins’ action is mediated by a structure containing at least one carbohydrate recognition domain (CRD). The potential prognostic value of galectins has been described in several neoplasms and helps clinicians predict disease outcome and determine therapeutic interventions. Currently, new therapeutic strategies involve the use of inhibitors such as competitive carbohydrates, small non-carbohydrate binding molecules and antibodies. This review outlines our current knowledge regarding the mechanism of action and potential therapy implications of galectins in cancer.

Galectin-7 in Epithelial Homeostasis and Carcinomas

Galectins are small unglycosylated soluble lectins distributed both inside and outside the cells. They share a conserved domain for the recognition of carbohydrates (CRD). Although galectins have a common affinity for β-galatosides, they exhibit different binding preferences for complex glycans. First described twenty years ago, galectin-7 is a prototypic galectin, with a single CRD, able to form divalent homodimers. This lectin, which is mainly expressed in stratified epithelia, has been described in epithelial tissues as being involved in apoptotic responses, in proliferation and differentiation but also in cell adhesion and migration. Most members of the galectins family have been associated with cancer biology. One of the main functions of galectins in cancer is their immunomodulating potential and anti-angiogenic activity. Indeed, galectin-1 and -3, are already targeted in clinical trials. Another relevant function of galectins in tumour progression is their ability to regulate cell migration and cell adhesion. Among these galectins, galectin-7 is abnormally expressed in various cancers, most prominently in carcinomas, and is involved in cancer progression and metastasis but its precise functions in tumour biology remain poorly understood. In this issue, we will focus on the physiological functions of galectin-7 in epithelia and present the alterations of galectin-7 expression in carcinomas with the aim to describe its possible functions in tumour progression.

Expression of Sialyl Lewis a, Sialyl Lewis x, Lewis y, Gal-3, Gal-7, STMN1 and p16 in cervical dysplasia

AIM

Cervical intraepithelial neoplasia (CIN) is commonly divided into three grades. Guidelines increasingly recommend surgery only in CIN 3 lesions. We investigated markers to evaluate differences in CIN 2 and 3 lesions as well as possible predictors for regression/progression in CIN 2 lesions.

MATERIALS & METHODS

Biopsies (n = 128) of healthy cervical tissue and CIN 1-3 were stained for Sialyl Lewis a, Sialyl Lewis x, Lewis y, Gal-3, Gal-7, STMN1 and p16.

RESULTS

We observed significant differences between CIN 2 and 3 lesions for Sialyl Lewis a, Sialyl Lewis x, Gal-3, Gal-7, STMN1 and p16. Expression of Sialyl Lewis a was significantly higher in CIN 2 patients who progressed during follow-up.

CONCLUSION

Significant differences in marker expression support the differentiation of CIN 2 and 3. Lewis a may help to predict progression/regression in CIN 2 patients.

Clinical significance of galectin-7 in vulvar squamous cell carcinoma

The present study reports the role of galectin-7 (Gal-7) expression in vulvar squamous cell carcinoma (VSCC) and its correlation with clinicopathological variables. Gal-7 expression was immunohistochemically detected in the paraffin-embedded sections of 20 normal vulvar biopsy samples and 50 VSCC specimens. Expression was also detected in 10 normal vulvar biopsy samples and 10 VSCC specimens by western blotting. In addition, the methylation status of the promoter of the Gal-7 gene was determined in 30 VSCC specimens and 20 samples of normal vulvar tissue by methylation-specific polymerase chain reaction. Gal-7 expression was found to be significantly downregulated in the VSCC tissues compared with the normal vulvar tissues (P<0.05). Downregulation of Gal-7 was correlated with advanced clinical stage, poor tumor differentiation and regional lymph node metastasis (P<0.05). Furthermore, methylation of the Gal-7 gene promoter was significantly reduced in the vulvar normal tissues compared with the VSCC tissues (P=0.023), while increased Gal-7 promoter methylation was correlated with advanced clinical stage, poor tumor differentiation and regional lymph node metastasis (P<0.05). There was no association between patient age and Gal-7 promoter methylation. Together, these results suggested that Gal-7 has a negative impact in patients with VSCC, with malignant potential correlating with Gal-7 promoter methylation.

Galectins: Double-edged Swords in the Cross-roads of Pregnancy Complications and Female Reproductive Tract Inflammation and Neoplasia

Galectins are an evolutionarily ancient and widely expressed family of lectins that have unique glycan-binding characteristics. They are pleiotropic regulators of key biological processes, such as cell growth, proliferation, differentiation, apoptosis, signal transduction, and pre-mRNA splicing, as well as homo- and heterotypic cell-cell and cell-extracellular matrix interactions. Galectins are also pivotal in immune responses since they regulate host-pathogen interactions, innate and adaptive immune responses, acute and chronic inflammation, and immune tolerance. Some galectins are also central to the regulation of angiogenesis, cell migration and invasion. Expression and functional data provide convincing evidence that, due to these functions, galectins play key roles in shared and unique pathways of normal embryonic and placental development as well as oncodevelopmental processes in tumorigenesis. Therefore, galectins may sometimes act as double-edged swords since they have beneficial but also harmful effects for the organism. Recent advances facilitate the use of galectins as biomarkers in obstetrical syndromes and in various malignancies, and their therapeutic applications are also under investigation. This review provides a general overview of galectins and a focused review of this lectin subfamily in the context of inflammation, infection and tumors of the female reproductive tract as well as in normal pregnancies and those complicated by the great obstetrical syndromes.

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.

High S100A8 and S100A12 protein expression is a favorable prognostic factor for survival of oropharyngeal squamous cell carcinoma

S100/calgranulins (S100A8, S100A9 and S100A12) are key players of innate immune function and elevated levels are a characteristic feature of acute and chronic inflammation, and inflammation-associated carcinogenesis. However, reduced S100A8 and S100A9 expression has been detected for squamous cell carcinoma, including the head and neck region (HNSCC), which originate from mucosal epithelia with abundant expression of both proteins under physiological conditions. In contrast to S100A8 and S100A9, only sparse information is available for S100A12 and a comparative study of all three S100/calgranulins in HNSCC is still missing. We analyzed S100/calgranulin protein levels in a retrospective patient cohort (n = 131) of oropharyngeal squamous cell carcinoma (OPSCC) by immunohistochemical staining of tissue microarrays. Common characteristics of all three S100/calgranulins were: (i) abundant expression in supra-basal keratinocytes of normal mucosa with predominant nuclear staining, (ii) low expression in 30.4-51.9% of primary OPSCCs and (iii) variable accumulation of S100/calgranulin-positive immune cells in the tumor stroma. These features were associated with histopathological characteristics, such as tumor grade, lymph node metastasis and tumor stage. Furthermore, univariate and multivariate analysis revealed worse overall survival of OPSCC patients with simultaneous reduction of S100A8 and S100A12 expression, while expression of S100A9 or presence of the S100A8/S100A9 heterodimer had no impact, suggesting distinct regulation and function of individual S100/calgranulins in the pathogenesis of HNSCCs.

Galectin-7 is epigenetically-regulated tumor suppressor in gastric cancer

Gastric cancer is the second leading cause of cancer death and remains a major clinical challenge due to poor prognosis and limited treatment options. Therefore, the basic mechanisms underlying gastric tumorigenesis deserve investigation. Although regulation of the galactoside-binding lectin galectin-7 in cancer has been studied, its role in tumor formation and progression remains controversial. In this study, we investigated galectin-7 expression and its role in gastric cancer. Immunohistochemical staining using a tissue microarray of gastric cancer patients revealed significantly low expression levels of galectin-7 in malignant tissues compared with matched normal tissues, and decreased expression of galectin-7 in malignant tissues was associated with advanced TMN stage disease (p =0.034). Importantly, low expression of galectin-7 in normal tissues was associated with a poor survival rate (p =0.0561). Over-expression of galectin-7 in AGS gastric adenocarcinoma cells suppressed cell proliferation, migration, and invasion, whereas ablation of galectin-7 in KATO III gastric carcinoma cells reversed these properties. AGS cells that overexpressed galectin-7 could not form gastric tumors in xenografted mice. More than 70% hypermethylation was observed in 7 of 9 gastric cancer cell lines tested and 5-aza-cytidine treatment lowered galectin-7 expression by reducing methylation in 24 cancer cell lines from five different organ origins. We analyzed CpG islands in the galectin-7 genomic region and detected hypermethylation at +1566bp of exon 2, the predicted p53 binding region. DNA hypermethylation of this region was also detected in gastric cancer tissues from 20 patients. Taken together, our data indicate that galectin-7 has a tumor suppressive function, and that the gene is epigenetically modified by DNA methylation and significantly down-regulated in gastric cancer. Further study of galectin-7 regulation may lead to improved gastric cancer diagnosis and therapy.

Galectin-7 as a potential predictive marker of chemo- and/or radio-therapy resistance in oral squamous cell carcinoma

Treatment of advanced oral squamous cell carcinoma (OSCC) requires the integration of multimodal approaches. The aim of this study was to identify predictors of tumor sensitivity to preoperative radiotherapy/chemotherapy for OSCC in order to allow oncologists to determine optimum therapeutic strategies without the associated adverse effects. Here, the protein expression profiles of formalin-fixed paraffin-embedded (FFPE) tissue samples from 18 OSCC patients, termed learning cases, who received preoperative chemotherapy and/or radiotherapy followed by surgery were analyzed by quantitative proteomics and validated by immunohistochemistry in 68 test cases as well as in the 18 learning cases. We identified galectin-7 as a potential predictive marker of chemotherapy and/or radiotherapy resistance, and the sensitivity and specificity of the galectin-7 prediction score (G7PS) in predicting this resistance was of 96.0% and 39.5%, respectively, in the 68 test cases. The cumulative 5-year disease-specific survival rate was 75.2% in patients with resistant prediction using G7PS and 100% in patients with sensitive prediction. In vitro overexpression of galectin-7 significantly decreased cell viability in OSCC cell line. Therefore, our findings suggest that galectin-7 is a potential predictive marker of chemotherapy and/or radiotherapy resistance in patients with OSCC.

Identification of proteins differentially expressed in OSSC samples from patients sensitive or resistant. The samples were processed by LC-MS and analyzed with 2DICAL.

S100A9 has a protective role in inflammation-induced skin carcinogenesis

The S100A8/A9 heterodimer is expressed by myeloid cells where its function has been extensively investigated. Immune cell S100A8/A9 promotes proinflammatory effects, and its absence is often associated with lack of leukocyte recruitment resulting in protection in terms of disease progression. S100A8/A9 is also expressed by certain epithelia, either constitutively as in mucosal epithelia or following stimulation as in skin keratinocytes. The role of the heterodimer in this context has not been as frequently explored. In this study, the incidence of skin papillomas induced by 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA) in S100a9(-/-) mice has been investigated. Unlike the immune disorders and certain models of cancer, absence of S100A8/A9 caused an increased incidence in skin of papillomas and, subsequently, squamous cell carcinomas. Although associated in S100a9(-/-) mice with increased recruitment of neutrophils and T cells, a bone marrow chimera experiment revealed the major defect to be primarily due to the absence of S100A8/A9 in the skin keratinocytes. S100a9(-/-) skin displayed enhanced Ki-67 expression over the time period of appearance of the papillomas suggesting an effect of S100A8/A9 in regulating proliferation in the epidermal layer. Thus, despite immune cell recruitment in S100a9(-/-) mouse skin that might have been predicted to promote tumor growth, it was the absence of S100A8/A9 in skin keratinocytes that dominated in terms of papilloma formation. The study highlights the importance of the S100A8/A9-expressing skin epidermal layer in controlling skin tumor formation and suggests that the influence of the heterodimer is dependent on the tissue context in which it is expressed.

Intracellular galectins in cancer cells: potential new targets for therapy (Review)

Dysregulation of galectin expression is frequently observed in cancer tissues. Such an abnormal expression pattern often correlates with aggressiveness and relapse in many types of cancer. Because galectins have the ability to modulate functions that are important for cell survival, migration and metastasis, they also represent attractive targets for cancer therapy. This has been well-exploited for extracellular galectins, which bind glycoconjugates expressed on the surface of cancer cells. Although the existence of intracellular functions of galectins has been known for many years, an increasing number of studies indicate that these proteins can also alter tumor progression through their interaction with intracellular ligands. In fact, in some instances, the interactions of galectins with their intracellular ligands seem to occur independently of their carbohydrate recognition domain. Such findings call for a change in the basic assumptions, or paradigms, concerning the activity of galectins in cancer and may force us to revisit our strategies to develop galectin antagonists for the treatment of cancer.

Expression and function of galectins in the endometrium and at the human feto-maternal interface

Galectins are classified as lectins that share structural similarities and bind β-galactosides via a conserved carbohydrate recognition domain. So far 16 out of 19 identified galectins were shown to be present in humans and numerous studies revealed galectins as pivotal modulators of cell death, differentiation and growth. Galectins were highlighted to interact with both the adaptive and innate immune response. In the field of reproductive medicine and placenta research different roles for galectins have been proposed. Several galectins, being abundantly present at the human feto-maternal interphase and endometrium, were hypothesized to significantly contribute to endometrial receptivity and pregnancy physiology. Hence, this review outlines selected aspects of galectin action within endometrial function and at the feto-maternal interphase. Further current knowledge on galectins in reproductive and pregnancy disorders like endometriosis, abortion or preeclampsia is summarized.