Galectin-7 Expression Potentiates HER-2-Positive Phenotype in Breast Cancer

Galectin 7 leads to a relative reduction in CD4+ T cells, mediated by PD-1

The role of glycan-binding proteins as an activator of immune regulatory receptors has gained attention recently. We report that galectin 7 reduced CD4+ T cell percentage in both in vitro culture and mouse tumor models. Immunohistochemical staining of esophageal cancer patient samples showed a lower percentage of CD4+ cells in the galectin 7 high area. The lack of CD4+ T cell depletion by galectin 7 in PD-1 knockout mice supports the role of PD-1 in mediating the effects of galectin 7. The binding assays demonstrate that galectin 7 binds to the N-glycosylation of PD-1 on N74 and N116 sites and leads to the recruitment of SHP-2. NFAT suppressive activity of galectin 7 was abrogated upon overexpression of the dominant negative SHP-2 mutant or inhibition of PD-1 by siRNA. Glycosylation of PD-1 has been reported to play a critical role in surface expression, stability, and interaction with its ligand PD-L1. This report further expands the significance of PD-1 glycosylation and suggests that galectin 7, a glycan-binding protein, interacts with the immune regulatory receptor PD-1 through glycosylation recognition.

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.

Galectin-9 Signaling Drives Breast Cancer Invasion through Extracellular Matrix

Aberrations in glycan and lectin expression and function represent one of the earliest hallmarks of cancer. Among galectins, a conserved family of β-galactoside-binding lectins, the role of Galectin-9 in immune-tumor interactions is well-established, although its effect on cancer cell behavior remains unclear. In this study, we assayed for, and observed, an association between Galectin-9 expression and invasiveness of breast cancer cells in vitro and in vivo. Genetic perturbation and pharmacological inhibition using novel cognate inhibitors confirmed a positive correlation between Galectin-9 levels and the adhesion of invasive cancer cells to─and their invasion through─constituted organomimetic extracellular matrix microenvironments. Signaling experiments and unbiased quantitative proteomics revealed Galectin-9 induction of Focal Adhesion Kinase activity and S100A4 expression, respectively. FAK inhibition decreased S100A4 mRNA levels. Our results provide crucial insights into how elevated Galectin-9 expression potentiates the invasiveness of breast cancer cells during early steps of invasion.

Overexpression of galectin2 (LGALS2) predicts a better prognosis in human breast cancer

BACKGROUND

Galectins (LGALS) are a family of carbohydrate-binding proteins, and LGALS family members have shown prognostic roles in various types of cancers. However, the prognostic significance of some LGALS family members has not been studied in breast malignancy.

METHODS

The prognostic value of LGALS family mRNA expression in breast cancer patients was investigated according to distinct clinicopathological features (including lymph node, intrinsic subtype, pathological grade, HER2, and TP53 status) using the Kaplan-Meier plotter database. Quantitative real-time polymerase chain reaction and western blotting were used to detect the mRNA and protein expression of LGALS in breast cancer and normal breast cells. The aberrant expression of specific LGALS and its correlation with breast cancer outcomes remains elusive. In the present analysis, we comprehensively explored an immunohistochemistry-based map of protein expression profiles in normal tissues, cancer, and cell lines from the widely available Human Protein Atlas (HPA) database. Immunohistochemistry was applied to evaluate the expression of LGALS between cancer and normal tissues.

RESULTS

Our results showed that overexpression of LGALS2 mRNA were correlated with satisfactory overall survival among all breast cancer patients. Furthermore, LGALS2 and LGALS4 expression correlated with a better overall survival (OS) in grade III breast cancer patients; LGALS2 also predicted a better OS in basal-like subtype patients, luminal B patients, HER2-overexpressing patients, TP53 mutated and wild breast cancer patients. Notably, the mRNA and protein expression levels of LGALS2 were decreased in cancer cells compared with normal cells (P<0.05). Furthermore, LGALS2 expression in immunostaining score was lower in cancer tissues than in normal tissues (P<0.005).

CONCLUSION

In conclusion, LGALS2 has potential as a valuable biomarker for envisaging a satisfactory prognosis in patients with breast tumours, particularly those with luminal and basal B types, all stages and grade III tumours.

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.

Opposing transcriptional programs of KLF5 and AR emerge during therapy for advanced prostate cancer

Endocrine therapies for prostate cancer inhibit the androgen receptor (AR) transcription factor. In most cases, AR activity resumes during therapy and drives progression to castration-resistant prostate cancer (CRPC). However, therapy can also promote lineage plasticity and select for AR-independent phenotypes that are uniformly lethal. Here, we demonstrate the stem cell transcription factor Krüppel-like factor 5 (KLF5) is low or absent in prostate cancers prior to endocrine therapy, but induced in a subset of CRPC, including CRPC displaying lineage plasticity. KLF5 and AR physically interact on chromatin and drive opposing transcriptional programs, with KLF5 promoting cellular migration, anchorage-independent growth, and basal epithelial cell phenotypes. We identify ERBB2 as a point of transcriptional convergence displaying activation by KLF5 and repression by AR. ERBB2 inhibitors preferentially block KLF5-driven oncogenic phenotypes. These findings implicate KLF5 as an oncogene that can be upregulated in CRPC to oppose AR activities and promote lineage plasticity.

Diagnostic Tools and Biomarkers for Severe Drug Eruptions

In accordance with the development of human technology, various medications have been speedily developed in the current decade. While they have beneficial impact on various diseases, these medications accidentally cause adverse reactions, especially drug eruption. This delayed hypersensitivity reaction in the skin sometimes causes a life-threatening adverse reaction, namely Stevens-Johnson syndrome and toxic epidermal necrolysis. Therefore, how to identify these clinical courses in early time points is a critical issue. To improve this problem, various biomarkers have been found for these severe cutaneous adverse reactions through recent research. Granulysin, Fas ligands, perforin, and granzyme B are recognized as useful biomarkers to evaluate the early onset of Stevens-Johnson syndrome and toxic epidermal necrolysis, and other biomarkers, such as miRNAs, high mobility group box 1 protein (HMGB1), and S100A2, which are also helpful to identify the severe cutaneous adverse reactions. Because these tools have been currently well developed, updates of the knowledge in this field are necessary for clinicians. In this review, we focused on the detailed biomarkers and diagnostic tools for drug eruption and we also discussed the actual usefulness of these biomarkers in the clinical aspects based on the pathogenesis of drug eruption.

High Galectin-7 and Low Galectin-8 Expression and the Combination of both are Negative Prognosticators for Breast Cancer Patients

Galectins are commonly overexpressed in cancer cells and their expression pattern is often associated with the aggressiveness and metastatic phenotype of the tumor. This study investigates the prognostic influence of the expression of galectin-7 (Gal-7) and galectin-8 (Gal-8) in tumor cell cytoplasm, nucleus and on surrounding immune cells. Primary breast cancer tissue of 235 patients was analyzed for the expression of Gal-7 and Gal-8 and correlated with clinical and pathological data and the outcome. To identify immune cell subpopulations, immunofluorescence double staining was performed. Significant correlations of Gal-7 expression in the cytoplasm with HER2-status, PR status, patient age and grading, and of Gal-8 expression in the cytoplasm with HER2-status and patient age and of both galectins between each other were found. A high Gal-7 expression in the cytoplasm was a significant independent prognosticator for an impaired progression free survival (PFS) (p = 0.017) and distant disease-free survival (DDFS) (p = 0.030). Gal-7 was also expressed by tumor-infiltrating macrophages. High Gal-8 expression in the cytoplasm was associated with a significantly improved overall survival (OS) (p = 0.032). Clinical outcome in patients showing both high Gal-7 and with low Gal-8 expression was very poor. Further understanding of the role of galectins in the regulation and interaction of tumor cells and macrophages is essential for finding new therapeutic targets.

Efficacy analysis of trastuzumab, carboplatin and docetaxel in HER-2-positive breast cancer patients

Efficacy of trastuzumab, carboplatin and docetaxel in human epidermal growth factor receptor-2 (HER-2)-positive breast cancer patients was investigated. A total of 180 HER-2-positive breast cancer patients admitted to The First People's Hospital of Yunnan Province were selected, of which 80 patients were treated with carboplatin and docetaxel and served as the control group (CG), and 100 patients were treated with trastuzumab, carboplatin and docetaxel and served as the research group (RG). Clinical efficacy, pathological efficacy, adverse reactions, inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), cellular immune indexes of T-lymphocyte subsets (CD4⁺, CD8⁺, CD4⁺/CD8⁺), and the oxidative stress indexes superoxide dismutase (SOD) and myeloperoxidase (MPO) were observed before and after treatment and were compared between both groups. Patients were followed up for 5 years, and the 5-year disease-free survival (DFS), as well as the overall survival (OS) were compared. Clinical efficacy and pathological efficacy in the RG were significantly higher than those in the CG, and the incidence rate of adverse reactions had no significant difference between the two groups. There was no significant difference in inflammatory factors, cellular immune indexes and oxidative stress indexes between the two groups before treatment. After treatment, the levels of IL-6, TNF-α, CD8⁺ and MPO in both groups were significantly reduced and were significantly lower in RG than those in CG. However, the levels of CD4⁺, CD4⁺/CD8⁺ and SOD in both groups were significantly increased after treatment and were significantly higher in RG than those in CG. The 5-year DFS and OS of the RG were significantly higher than those of the CG. In conclusion, trastuzumab, carboplatin and docetaxel present high efficacy, safety, and 5-year DFS and OS in HER-2-positive breast cancer patients, and have good recovery effect on inflammation, immune response and oxidative stress.

Expression of galectin-7 in vulvar lichen sclerosus and its effect on dermal fibroblasts

Lichen sclerosus is a chronic and inflammatory disease. Extensive studies have focused on the epidermis, with the dermis or epidermis-dermis receiving less attention. To investigate the role of galectin-7, a keratinocyte protein, in vulvar lichen sclerosus (VLS) and its potential effects on dermal fibroblasts, immunohistochemical staining was performed with VLS tissue samples and normal control samples. The expression of galectin-7 was determined by evaluating the galectin-7 integrated density analysis, and further assessed by western blot analysis. Dermal fibroblasts were isolated from the normal tissue of the female anogenital region following sexual plastic surgery. A cell viability assay was performed on isolated dermal fibroblast cells in the presence or absence of galectin-7. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to determine the transcriptional level of collagen I and collagen III in the response to different doses of galectin-7. In the immunohistochemical analysis, galectin-7 demonstrated a significantly elevated level in VLS, compared to control tissues, which was confirmed by western blot analysis. In the analysis of primary dermal fibroblast cells, galectin-7 significantly inhibited the viability rate of fibroblasts in a dose-dependent manner. RT-qPCR data revealed that the transcription level of collagen I and collagen III were positively associated with the galectin-7 treatment concentration. The overexpression of galectin-7 is associated with the progression of VLS in the epidermis, a high concentration of galectin-7 inhibits the viability of the primary vulvar dermal fibroblasts, and stimulates the accumulation of collagen I and collagen III in dermal fibroblast cultures, thus galectin-7 may serve as a drug target during VLS progression.

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.