Cosmc Disruption-Mediated Aberrant O-glycosylation Suppresses Breast Cancer Cell Growth via Impairment of CD44

Tn antigen promotes breast cancer metastasis via impairment of CASC4

Breast cancer is one of the most serious and deadly cancers in women worldwide, with distant metastases being the leading cause of death. Tn antigen, a tumor-associated carbohydrate antigen, was frequently detected in breast cancer, but its exact role in breast cancer metastasis has not been well elucidated. Here we investigated the impact of Tn antigen expression on breast cancer metastasis and its underlying mechanisms. The expression of Tn antigen was induced in two breast cancer cell lines by deleting T-synthase or Cosmc, both of which are required for normal O-glycosylation. It showed that Tn-expressing cancer cells promoted epithelial-mesenchymal transition (EMT) and metastatic features as compared to Tn(-) control cells both in vitro and in vivo. Mechanistically, we found that cancer susceptibility candidate 4 (CASC4), a heavily O-glycosylated protein, was significantly downregulated in both Tn(+) cells. Overexpression of CASC4 suppressed Tn-induced activation of EMT and cancer metastasis via inhibition of Cdc42 signaling. Furthermore, we confirmed that O-glycosylation is essential for the functional role of CASC4 because defective O-glycosylated CASC4 (mutant CASC4, which lacks nine O-glycosylation sites) exerted marginal metastatic-suppressing effects in comparison with WT CASC4. Collectively, these data suggest that Tn-mediated aberrant O-glycosylation contributes to breast cancer metastasis via impairment of CASC4 expression and function.

Novel blood-based FUT7 DNA methylation is associated with lung cancer: especially for lung squamous cell carcinoma

BACKGROUND

The death rate of lung cancer (LC) ranks first in the world. Changes of DNA methylation in peripheral blood may be related to malignant tumors. It is necessary to explore blood-based biomarkers of methylation to detect LC.

METHODS

Mass spectrometry assays were conducted to measure DNA methylation levels of seven CpG sites within FUT7 gene in the peripheral blood of 428 patients with LC, 233 patients with benign pulmonary nodule (BPN) and 862 normal controls (NC). The odds ratios (ORs) of all CpG sites were evaluated for their risk to LC using per SD change and tertiles analyses by logistic regression. The predictive ability of the seven FUT7 CpG sites and risk factors were evaluated by receiver operating characteristic curve (ROC).

RESULTS

The methylation levels of seven CpG sites of FUT7 in LC were significantly lower than that in NC (P < 0.05). The per SD decrement of methylation level in CpG_1-7 was significantly associated with 65%, 38%, 59%, 46%, 23%, 20% and 68% higher risk for LC versus NC, respectively, and the adjusted ORs (95% CI) were 2.92 (2.17-3.96), 1.76 (1.29-2.38), 2.83 (2.09-3.82), 3.00 (2.17-4.16), 1.81 (1.35-2.43), 1.48 (1.11-1.97) and 3.04 (2.23-4.16) for the lowest tertiles of methylation level in CpG_1-7 compared with the top tertiles, respectively. The area under the curve (AUC) of FUT7_CpG_1-7 was 0.659 (CI 0.626-0.693), 0.792 (CI 0.736-0.848) and 0.729 (CI 0.665-0.792) in distinguishing LC versus NC, LUSC versus NC and LUSC versus BPN.

CONCLUSIONS

Our study revealed an association between FUT7 hypomethylation and LC, especially for LUSC, which provides novel support for the blood-based methylation signatures as potential marker for assessing lung cancer risk.

Glycosylation in Renal Cell Carcinoma: Mechanisms and Clinical Implications

Renal cell carcinoma (RCC) is one of the most prevalent malignant tumors of the urinary system, accounting for around 2% of all cancer diagnoses and deaths worldwide. Clear cell RCC (ccRCC) is the most prevalent and aggressive histology with an unfavorable prognosis and inadequate treatment. Patients' progression-free survival is considerably improved by surgery; however, 30% of patients develop metastases following surgery. Identifying novel targets and molecular markers for RCC prognostic detection is crucial for more accurate clinical diagnosis and therapy. Glycosylation is a critical post-translational modification (PMT) for cancer cell growth, migration, and invasion, involving the transfer of glycosyl moieties to specific amino acid residues in proteins to form glycosidic bonds through the activity of glycosyltransferases. Most cancers, including RCC, undergo glycosylation changes such as branching, sialylation, and fucosylation. In this review, we discuss the latest findings on the significance of aberrant glycans in the initiation, development, and progression of RCC. The potential biomarkers of altered glycans for the diagnosis and their implications in RCC have been further highlighted.

CD44 Glycosylation as a Therapeutic Target in Oncology

The interaction of non-kinase transmembrane glycoprotein CD44 with ligands including hyaluronic acid (HA) is closely related to the occurrence and development of tumors. Changes in CD44 glycosylation can regulate its binding to HA, Siglec-15, fibronectin, TM4SF5, PRG4, FGF2, collagen and podoplanin and activate or inhibit c-Src/STAT3/Twist1/Bmi1, PI3K/AKT/mTOR, ERK/NF-κB/NANOG and other signaling pathways, thereby having a profound impact on the tumor microenvironment and tumor cell fate. However, the glycosylation of CD44 is complex and largely unknown, and the current understanding of how CD44 glycosylation affects tumors is limited. These issues must be addressed before targeted CD44 glycosylation can be applied to treat human cancers.

Expression and Impact of C1GalT1 in Cancer Development and Progression

Simple Summary

C1GalT1 is one of the enzymes that catalyze the addition of sugar residues to proteins (protein glycosylation). It specifically controls the synthesis and formation of a special disaccharide structure Galβ1,3GalNAcα-, which occurs predominately in cancer but rarely in normal cells. Recent studies have shown that C1GalT1 is overexpressed in many common cancers including colon, breast, gastric, lung, head and neck, pancreatic, esophageal, prostate, and hepatocellular cancer. C1GalT1 overexpression is also often associated with poorer prognosis and poorer patient survival. This review summarizes our current understanding of the expression of C1GalT1 in various cancers and discusses the impact of C1GalT change on cancer cell activities in cancer development and progression.

Abstract

C1GalT1 (T-synthase) is one of the key glycosyltransferases in the biosynthesis of O-linked mucin-type glycans of glycoproteins. It controls the formation of Core-1 disaccharide Galβ1,3GalNAcα- (Thomsen–Friedenreich oncofetal antigen, T or TF antigen) and Core-1-associated carbohydrate structures. Recent studies have shown that C1GalT1 is overexpressed in many cancers of epithelial origin including colon, breast, gastric, head and neck, pancreatic, esophageal, prostate, and hepatocellular cancer. Overexpression of C1GalT1 is often seen to also be associated with poorer prognosis and poorer patient survival. Change of C1GalT1 expression causes glycosylation changes of many cell membrane glycoproteins including mucin proteins, growth factor receptors, adhesion molecules, and death receptors. This leads to alteration of the interactions of these cell surface molecules with their binding ligands, resulting in changes of cancer cell activity and behaviors. This review summarizes our current understanding of the expression of C1GalT1 in various cancers and discusses the impact of C1GalT change on cancer cell activities in cancer development and progression.

FUT7 Promotes the Epithelial-Mesenchymal Transition and Immune Infiltration in Bladder Urothelial Carcinoma

Background

Bladder urothelial carcinoma (BLCA) is one of the most frequently appearing, lethal and aggressive malignancies of the genitourinary system with growing morbidity and mortality, which affects human health seriously. Protein glycosylation, catalyzed by specific glycosyltransferase, has been found to be abnormal in several diseases, especially cancer. Fucosyltransferase VII (FUT7), one of the fucosyltransferases, was observed abnormally expressed in various cancers, however, the role of FUT7 in BLCA, and the association between its expression and clinical outcomes or immune infiltration remains unclear.

Methodology

FUT7 expression in BLCA was analyzed in Oncomine database, which was further confirmed with immunohistochemistry and ELISA. The prognostic value of FUT7 for BLCA was evaluated with PrognoScan database, and its genetic alteration was examined in cBioPortal database. The proliferation, migration, invasion and epithelial–mesenchymal transition (EMT) changes of bladder cancer cells after FUT7 siRNA or cDNA transfection were determined by CCK8, colony formation, transwell and Western blot, respectively. The correlation between FUT7 expression and immune infiltration levels was analyzed in TIMER and TISIDB databases, and the methylation level of FUT7 was detected in UALCAN database.

Results

The results showed that the expression of FUT7 was increased in BLCA, and patients with high FUT7 level were predicted to have lower overall survival and disease-specific survival rates, which were not influenced by FUT7 genetic alterations. Downregulation FUT7 inhibited the proliferation, migration, invasion and EMT of bladder cancer cells, whereas upregulation of FUT7 showed the opposite effects. We found that FUT7 was positively correlated with immune cell infiltration levels (CD8+ T cells, CD4+T cells, macrophage, neutrophil and dendritic cells), and also the expression of gene markers of immune cells. The negative correlation between FUT7 expression and FUT7 methylation level was observed, among which FUT7 expression was positively correlated with the abundance of 28 kinds of tumor-infiltrating lymphocytes (TILs), while FUT7 methylation level was negatively correlated with TILs.

Conclusion

Altogether, these findings suggested that FUT7 possessed the potential to serve as a detection biomarker or immunotherapeutic target for BLCA.

Tn Antigen Expression Contributes to an Immune Suppressive Microenvironment and Drives Tumor Growth in Colorectal Cancer

Expression of the tumor-associated glycan Tn antigen (αGalNAc-Ser/Thr) has been correlated to poor prognosis and metastasis in multiple cancer types. However, the exact mechanisms exerted by Tn antigen to support tumor growth are still lacking. One emerging hallmark of cancer is evasion of immune destruction. Although tumor cells often exploit the glycosylation machinery to interact with the immune system, the contribution of Tn antigen to an immunosuppressive tumor microenvironment has scarcely been studied. Here, we explored how Tn antigen influences the tumor immune cell composition in a colorectal cancer (CRC) mouse model. CRISPR/Cas9-mediated knock out of the C1galt1c1 gene resulted in elevated Tn antigen levels on the cell surface of the CRC cell line MC38 (MC38-Tn^high). RNA sequencing and subsequent GO term enrichment analysis of our Tn^high glycovariant not only revealed differences in MAPK signaling and cell migration, but also in antigen processing and presentation as well as in cytotoxic T cell responses. Indeed, MC38-Tn^high tumors displayed increased tumor growth in vivo, which was correlated with an altered tumor immune cell infiltration, characterized by reduced levels of cytotoxic CD8⁺ T cells and enhanced accumulation of myeloid-derived suppressor cells. Interestingly, no systemic differences in T cell subsets were observed. Together, our data demonstrate for the first time that Tn antigen expression in the CRC tumor microenvironment affects the tumor-associated immune cell repertoire.