Stage-specific embryonic antigen-4 is a histological marker reflecting the malignant behavior of prostate cancer

High expression of embryonic stem cell marker SSEA3 confers poor prognosis and promotes epithelial mesenchymal transition in hepatocellular carcinoma

BACKGROUND

Malignant cells may arise from dedifferentiation of mature cells and acquire features of the progenitor cells. Definitive endoderm from which liver is derived, expresses glycosphingolipids (GSLs) such as stage-specific embryonic antigen 3 (SSEA3), Globo H, and stage-specific embryonic antigen 4 (SSEA4). Herein, we evaluated the potential prognosis value of the three GSLs and biological functions of SSEA3 in hepatocellular carcinoma (HCC).

METHODS

The expression of SSEA3, Globo H, and SSEA4 in tumor tissues obtained from 328 patients with resectable HCC was examined by immunohistochemistry staining. Epithelial mesenchymal transition (EMT) and their related genes were analyzed by transwell assay and qRT-PCR, respectively.

RESULTS

Kaplan Meier survival analysis showed significantly shorter relapse-free survival (RFS) for those with higher expression of SSEA3 (p < 0.001), Globo H (p < 0.001), and SSEA4 (p = 0.005) and worse overall survival (OS) for those with high expression of either SSEA3 (p < 0.001) or SSEA4 (p = 0.01). Furthermore, multivariable Cox regression analysis identified the SSEA3 as an independent predictor for RFS (HR: 2.68, 95% CI: 1.93-3.72, p < 0.001) and OS (HR: 2.99, 95% CI: 1.81-4.96, p < 0.001) in HCC. Additionally, SSEA3-ceramide enhanced the EMT of HCC cells, as reflected by its ability to increase migration, invasion and upregulate the expression of CDH2, vimentin, fibronectin, and MMP2, along with ZEB1. Moreover, ZEB1 silencing abrogated the EMT-enhancing effects of SSEA3-ceramide.

CONCLUSIONS

Higher expression of SSEA3 was an independent predictor for RFS and OS in HCC and promoted EMT of HCC via upregulation of ZEB1.

Stemness properties of SSEA-4+ subpopulation isolated from heterogenous Wharton's jelly mesenchymal stem/stromal cells

Background: High heterogeneity of mesenchymal stem/stromal cells (MSCs) due to different degrees of differentiation of cell subpopulations poses a considerable challenge in preclinical studies. The cells at a pluripotent-like stage represent a stem cell population of interest for many researchers worldwide, which is worthy of identification, isolation, and functional characterization. In the current study, we asked whether Wharton's jelly-derived MSCs (WJ-MSCs) which express stage-specific embryonic antigen-4 (SSEA-4) can be considered as a pluripotent-like stem cell population. Methods: SSEA-4 expression in different culture conditions was compared and the efficiency of two cell separation methods were assessed: Magnetic Activated Cell Sorting (MACS) and Fluorescence Activated Cell Sorting (FACS). After isolation, SSEA-4+ cells were analyzed for the following parameters: the maintenance of the SSEA-4 antigen expression after cell sorting, stem cell-related gene expression, proliferation potential, clonogenicity, secretome profiling, and the ability to form spheres under 3D culture conditions. Results: FACS allowed for the enrichment of SSEA-4+ cell content in the population that lasted for six passages after sorting. Despite the elevated expression of stemness-related genes, SSEA-4+ cells neither differed in their proliferation and clonogenicity potential from initial and negative populations nor exhibited pluripotent differentiation repertoire. SSEA-4+ cells were observed to form smaller spheroids and exhibited increased survival under 3D conditions. Conclusion: Despite the transient expression of stemness-related genes, our findings could not fully confirm the undifferentiated pluripotent-like nature of the SSEA-4+ WJ-MSC population cultured in vitro.

Increased expression of SSEA-4 on TKI-resistant non-small cell lung cancer with EGFR-T790M mutation

Non-small cell lung cancer (NSCLC), a major life-threatening disease accounting for 85% of all lung cancer cases, has been treated with tyrosine kinase inhibitors (TKIs), but often resulted in drug resistance, and approximately 60% of TKI-resistant cases are due to acquired secondary (epithelial growth factor receptor) EGFR-T790M mutation. To identify alternative targets for TKI-resistant NSCLC with EGFR-T790M mutation, we found that the three globo-series glycosphingolipids are increasingly expressed on this type of NSCLC cell lines, and among them, the increase of stage-specific embryonic antigen-4 (SSEA-4) expression is the most significant. Compared to TKI-sensitive cell lines, SSEA-4 and the key enzyme β3GalT5 responsible for the synthesis of SSEA3 are more expressed in TKI-resistant NSCLC cell lines with EGFR-T790M mutation, and the expression levels strongly correlate with poor survival in patients with EGFR mutation. In addition, we demonstrated that a SSEA-4 targeted monoclonal antibody, especially the homogeneous glycoform with well-defined Fc glycan designed to improve effective functions, is highly effective against this subpopulation of NSCLC in cell-based and animal studies. These findings provide a direction for the prediction of tumor recurrence and treatment of TKI-resistant NSCLC with EGFR-T790M mutation.

Pathophysiological roles and applications of glycosphingolipids in the diagnosis and treatment of cancer diseases

Glycosphingolipids (GSLs) are major amphiphilic glycolipids present on the surface of living cell membranes. They have important biological functions, including maintaining plasma membrane stability, regulating signal transduction, and mediating cell recognition and adhesion. Specific GSLs and related enzymes are abnormally expressed in many cancer diseases and affect the malignant characteristics of tumors. The regulatory roles of GSLs in signaling pathways suggest that they are involved in tumor pathogenesis. GSLs have therefore been widely studied as diagnostic markers of cancer diseases and important targets of immunotherapy. This review describes the tumor-related biological functions of GSLs and systematically introduces recent progress in using diverse GSLs and related enzymes to diagnose and treat tumor diseases. Development of drugs and biomarkers for personalized cancer therapy based on GSL structure is also discussed. These advances, combined with recent progress in the preparation of GSLs derivatives through synthetic biology technologies, suggest a strong future for the use of customized GSL libraries in treating human diseases.

Human amniotic epithelial cells exert anti-cancer effects through secretion of immunomodulatory small extracellular vesicles (sEV)

We identified here mechanism by which hAECs exert their anti-cancer effects. We showed that vaccination with live hAEC conferred effective protection against murine colon cancer and melanoma but not against breast cancer in an orthotopic cancer cell inoculation model. hAEC induced strong cross-reactive antibody response to CT26 cells, but not against B16F10 and 4T1 cells. Neither heterotopic injection of tumor cells in AEC-vaccinated mice nor vaccination with hAEC lysate conferred protection against melanoma or colon cancer. Nano-sized AEC-derived small-extracellular vesicles (sEV) (AD-sEV) induced apoptosis in CT26 cells and inhibited their proliferation. Co-administration of AD-sEV with tumor cells substantially inhibited tumor development and increased CTL responses in vaccinated mice. AD-sEV triggered the Warburg’s effect leading to Arginine consumption and cancer cell apoptosis. Our results clearly showed that it is AD-sEV but not the cross-reactive immune responses against tumor cells that mediate inhibitory effects of hAEC on cancer development. Our results highlight the potential anti-cancer effects of extracellular vesicles derived from hAEC.

Anti-cancer effects of hAEC depend on cancer type.

Cross-reactive humoral responses do not mediate anti-cancer effects of hAEC.

Anti-cancer effects of hAECs are mainly mediated by small-extracellular vesicles (sEV).

hAEC-derived sEV (AD-sEV) trigger the Warburg’s effect leading to Arginine consumption and cancer cell apoptosis.

AD-sEV substantially inhibits tumor development and increases survival and CTL responses.

Sphingolipids and Lymphomas: A Double-Edged Sword

Lymphomas are a highly heterogeneous group of hematological neoplasms. Given their ethiopathogenic complexity, their classification and management can become difficult tasks; therefore, new approaches are continuously being sought. Metabolic reprogramming at the lipid level is a hot topic in cancer research, and sphingolipidomics has gained particular focus in this area due to the bioactive nature of molecules such as sphingoid bases, sphingosine-1-phosphate, ceramides, sphingomyelin, cerebrosides, globosides, and gangliosides. Sphingolipid metabolism has become especially exciting because they are involved in virtually every cellular process through an extremely intricate metabolic web; in fact, no two sphingolipids share the same fate. Unsurprisingly, a disruption at this level is a recurrent mechanism in lymphomagenesis, dissemination, and chemoresistance, which means potential biomarkers and therapeutical targets might be hiding within these pathways. Many comprehensive reviews describing their role in cancer exist, but because most research has been conducted in solid malignancies, evidence in lymphomagenesis is somewhat limited. In this review, we summarize key aspects of sphingolipid biochemistry and discuss their known impact in cancer biology, with a particular focus on lymphomas and possible therapeutical strategies against them.

ST3GAL2 knock-down decreases tumoral character of colorectal cancer cells in vitro and in vivo

Tumor cells have a modified glycosylation profile that promotes their evolution and/or their maintenance in the tumor. Sialylation is a type of glycosylation that is often altered in cancers. RNA-Seq database analysis revealed that the sialyltransferase gene ST3GAL2 is significantly overexpressed at all stages of colorectal cancer (CRC). ST3GAL2 sialylates both glycoproteins and glycolipids. The aim of this work was to investigate the involvement of ST3GAL2 in CRC. Using the HT29 tumor cell line derived from a stage II of CRC, we decreased the expression of ST3GAL2 by specific shRNA, and then characterized these cells by performing functional tests. We found that ST3GAL2 knock down (KD) significantly decreases tumor cell proliferation, cell migration and invasiveness properties in vitro. The cell cycle of these cells is affected with a change in cell cycle distribution and an increase of cell apoptosis. The effect of ST3GAL2 KD was then studied in vivo, following xenografts into nude mice, in which the tumor progression was significantly reduced. This work demonstrates that ST3GAL2 is a major player in the behavior of colorectal tumor cells, by modifying the sialylation state of glycoproteins and glycolipids which remain to be specifically identified.

The role of Globo H and SSEA-4 in the development and progression of cancer, and their potential as therapeutic targets

Glycans, chains of sugar molecules found conjugated to cell proteins and lipids, contribute to their growth, movement and differentiation. Aberrant glycosylation is a hallmark of several medical conditions including tumorigenesis. Glycosphingolipids (GSLs), consisting of glycans conjugated to a lipid (ceramide) core, are found in the lipid bilayer of eukaryotic cell membranes. GSLs, play an active role in cell processes. Several GSLs are expressed by human embryonic stem cells and have been found to be overexpressed in several types of cancer. In this review, we discuss the data, hypotheses and perspectives related to the GSLs Globo H and SSEA-4.

Combined Effect of Anti-SSEA4 and Anti-Globo H Antibodies on Breast Cancer Cells

The globo-series glycosphingolipids (SSEA3, SSEA4, and Globo H) were shown to express in many cancers selectively, and a combination of anti-SSEA4 and anti-Globo H antibodies was able to suppress tumor growth in mice inoculated with breast cancer cell lines. To further understand the effect, we focused on the combined effect of the two antibodies in target binding and antibody-dependent cellular cytotoxicity (ADCC) in vitro. Here, we report that the binding of anti-Globo H antibody (VK9) to MDA-MB231 breast cancer cells was influenced by anti-SSEA4 antibody (MC813-70), and a combination of both antibodies induced a similar effect as did anti-SSEA4 antibodies alone in a reporter-based ADCC assay, indicating that SSEA4 is a major target in breast cancer due to its higher expression than Globo H. Furthermore, we showed that a homogeneous anti-SSEA4 antibody (chMC813-70-SCT) designed to maximize the ADCC activity can be used to isolate a subpopulation of natural killer (NK) cells that exhibit an ∼23% increase in killing the target cells as compared to the unseparated NK cells. These findings can be used to predict a therapy outcome based on the expression levels of antigens and evaluate therapeutic antibody development.

A Diversity-Oriented Strategy for Chemoenzymatic Synthesis of Glycosphingolipids and Related Derivatives

A diversity-oriented strategy combining enzymatic glycan assembly and on-site lipid remodeling via chemoselective cross-metathesis and N-acylation was developed for glycosphingolipid (GSL) synthesis starting from a common, simple glycoside. The strategy was verified with a series of natural GSLs and GSL derivatives and showed several advantages. Most notably, it enabled two-way diversification of the glycan and lipid, including introduction of designed molecular tags, to provide functionalized GSLs useful for biological studies and applications.