Regulation of MMP-2 expression and activity by β-1,3-N-acetylglucosaminyltransferase-8 in AGS gastric cancer cells

Comprehensive prognostic and immune analysis of a glycosylation related risk model in pancreatic cancer

BACKGROUND

Pancreatic cancer (PC) is a malignant tumor with extremely poor prognosis, exhibiting resistance to chemotherapy and immunotherapy. Nowadays, it is ranked as the third leading cause of cancer-related mortality. Glycation is a common epigenetic modification that occurs during the tumor transformation. Many studies have demonstrated a strong correlation between glycation modification and tumor progression. However, the expression status of glycosylation-related genes (GRGs) in PC and their potential roles in PC microenvironment have not been extensively investigated.

METHOD

We systematically integrated RNA sequencing data and clinicopathological parameters of PC patients from TCGA and GTEx databases. A GRGs risk model based on glycosylation related genes was constructed and validated in 60 patients from Pancreatic biobank via RT-PCR. R packages were used to analyze the relationships between GRGs risk scores and overall survival (OS), tumor microenvironment, immune checkpoint, chemotherapy drug sensitivity and tumor mutational load in PC patients. Panoramic analysis was performed on PC tissues. The function of B3GNT8 in PC was detected via in vitro experiments.

RESULTS

In this study, we found close correlations between GRGs risk model and PC patients' overall survival and tumor microenvironment. Multifaceted predictions demonstrated the low-risk cohort exhibits superior OS compared to high-risk counterparts. Meanwhile, the low-risk group was characterized by high immune infiltration and may be more sensitive to immunotherapy or chemotherapy. Panoramic analysis was further confirmed a significant relationship between the GRGs risk score and both the distribution of PC tumor cells as well as CD8 + T cell infiltration. In addition, we also identified a unique glycosylation gene B3GNT8, which could suppress PC progression in vitro and in vivo.

CONCLUSION

We established a GRGs risk model, which could predict prognosis and immune infiltration in PC patients. This risk model may provide a new tool for PC precision treatment.

Knockdown of N-Acetylglucosaminyltransferase-II Reduces Matrix Metalloproteinase 2 Activity and Suppresses Tumorigenicity in Neuroblastoma Cell Line

Neuroblastoma (NB) development and progression are accompanied by changes in N-glycans attached to proteins. Here, we investigated the role of N-acetylglucosaminyltransferase-II (GnTII, MGAT2) protein substrates in neuroblastoma (NB) cells. MGAT2 was silenced in human BE(2)-C NB (HuNB) cells to generate a novel cell line, HuNB(-MGAT2), lacking complex type N-glycans, as in rat B35 NB cells. Changes in N-glycan types were confirmed by lectin binding assays in both cell lines, and the rescued cell line, HuNB(-/+MGAT2). Western blotting of cells heterologously expressing a voltage-gated K+ channel (Kv3.1b) showed that some hybrid N-glycans of Kv3.1b could be processed to complex type in HuNB(-/+MGAT2) cells. In comparing HuNB and HuNB(-MGAT2) cells, decreased complex N-glycans reduced anchorage-independent cell growth, cell proliferation, and cell invasiveness, while they enhanced cell-cell interactions. Cell proliferation, invasiveness and adhesion of the HuNB(-/+MGAT2) cells were more like the HuNB than HuNB(-MGAT2). Western blotting revealed lower protein levels of MMP-2, EGFR and Gab2 in glycosylation mutant cells relative to parental cells. Gelatin zymography demonstrated that decreased MMP-2 protein activity was related to lowered MMP-2 protein levels. Thus, our results support that decreased complex type N-glycans suppress cell proliferation and cell invasiveness in both NB cell lines via remodeling ECM.

Anti-cancer effect of dung beetle glycosaminoglycans on melanoma

BACKGROUND

Dung beetle glycosaminoglycan is known to possess anti-aging activities. However, its anti-cancer mechanisms are not fully elucidated yet. The objective of this study was to evaluate the anti-cancer effect of insect-derived polymer dung beetle glycosaminoglycan (GAG) after intraperitoneally injecting it to melanoma mice induced by B16F10 cells.

METHODS

To determine molecular mechanism involved in the anti-cancer effect of dung beetle GAG, its origin N-glycan under 3KD Dalton was assayed for melanoma cell cytotoxicity. Quantitative comparisons of adhesive molecule on extracellular matrix and activities of tissue inhibitor of metalloprotease 2 (TIMP-2) were also investigated. In vivo anti-cancer effect of dung beetle GAG on solid tumor size, survival time and gene-expression profiles was also assayed using B10F10 melanoma mice model. Mice with induced melanoma were then treated with Catharsius molossus (dung beetle) GAG (CaG) at 5 mg/kg for 8 weeks to investigate its anti-cancer effects compared to bumblebee (Bombus ignitus) queen glycosaminoglycan (IQG) and Huechys sanguinea glycosaminoglycan (HEG).

RESULTS

These N-glycans derived from these GAG were composed of many linear heparinoid polysaccharides, polymers with hexose and N-acetylhexose. Adminstration with these GAGs increased survival time and decreased melanoma sizes in mice, in accordance with their inhibitory effects on cell growth ratio of melanoma B16F10. In addition, treatment with N-glycans derived from theses glycosaminoglycan increased activities of TIMP-2 in HMVEC cells pretreated with TNF-alpha and in melanoma cells, suggesting that they had anti-inflammatory and anticancer activities. In DNA microarray results, compared to control, CaG treated mouse group showed upregulation of 192 genes including collagen,typeI,alpha1 (Col1a1), consistent with the highly increased in vitro extracellular matrix (ECM) adhesion on collagen 1 and up-regulation of heparanase (Hpse). After treatment with CaG, a total of 152 genes were down-regulated, including nuclear RNA export factor (Nxf3) and hyaluronan proteoglycan link protein1 (Hapln1).

CONCLUSIONS

Glycosaminoglycan, CaG can strengthen ECM by increasing activity of TIMP-2 and adhesion activity on collagen known to inhibit changes of ECM, leading to tumor cell invasion and progression.

β3GnT8 Promotes Gastric Cancer Invasion by Regulating the Glycosylation of CD147

β1, 3-N-acetylglucosminyltransferase 8(β3GnT8) synthesizes a unique cabohydrate structure known as polylactosamine, and plays a vital role in progression of various human cancer types. However, its involvement in gastric cancer remains unclear. In this study, we analyzed the expression and clinical significance of β3GnT8 by Western blot in 6 paired fresh gastric cancer tissues, noncancerous tissues and immunohistochemistry on 110 paraffin-embedded slices. β3GnT8 was found to be over-expressed in gastric cancer tissues, which correlated with lymph node metastasis and TNM stage. Forced the expression of β3GnT8 promoted migration and invasion of gastric cancer cells, whereas β3GnT8 knockdown led to the opposite results. Further studies showed that the regulated β3GnT8 could convert the heterogeneous N-glycosylated forms of CD147 and change the polylactosamine structures carried on CD147. In addition, our data suggested the annexin A2 (ANXA2) to be an essential interaction partner of β3GnT8 during the process of CD147 glycosylation. Collectively, these results provide a novel molecular mechanism for β3GnT8 in promotion of gastric cancer invasion and metastasis. Targeting β3GnT8 could serve as a new strategy for future gastric cancer therapy.

Transcription factor c-jun regulates β3Gn-T8 expression in gastric cancer cell line SGC-7901

Aberrant glycosylation, a common feature of malignant alteration, is partly due to changes in the expression of glycosyltransferases, including β1,3-N-acetyl-glucosaminyltrans-ferase 8 (β3Gn‑T8), which synthesizes poly-N-acetyllactosamine (poly-LacNAc) chains on β1,6 branched N‑glycans. Although the role of β3Gn‑T8 in tumors has been reported, the regulation of β3Gn‑T8 expression, however, is still poorly understood. In the present study, we used three online bioinformatic software tools to identify multiple c‑jun binding sites in the promoter of the β3Gn‑T8 gene. Using luciferase reporter assay, chromatin immunoprecipitation (ChIP) analysis, RT‑PCR and western blot analysis, we revealed that c‑jun could bind to and activate the β3Gn‑T8 promoter, thus upregulating β3Gn‑T8 expression. This was also confirmed by changes in β3Gn‑T8 activity as demonstrated by flow cytometry, immunofluorescence and lectin blot analysis using LEA lectin. Moreover, expression of glycoprotein HG‑CD147, the substrate of β3Gn‑T8, was also regulated by c‑jun. In addition, c‑jun and β3Gn‑T8 were more highly expressed in the gastric cancer tissues when compared to these levels in the adjacent non‑tumor gastric tissues, and β3Gn‑T8 expression was positively correlated with c‑jun expression. These results suggest that c‑jun plays a significant role in regulating the expression of β3Gn‑T8 in the SGC‑7901 cell line and may be involved in the development of malignancy via the activity of β3Gn‑T8.

B3GNT3 Expression Is a Novel Marker Correlated with Pelvic Lymph Node Metastasis and Poor Clinical Outcome in Early-Stage Cervical Cancer

BACKGROUND

The β1,3-N-acetylglucosaminyltransferase-3 gene (B3GNT3) encodes a member of the B3GNT family that functions as the backbone structure of dimeric sialyl-Lewis A and is involved in L-selectin ligand biosynthesis, lymphocyte homing and lymphocyte trafficking. B3GNT3 has been implicated as an important element in the development of certain cancers. However, the characteristics of B3GNT3 in the development and progression of cancer remain largely unknown. Thus, our study aimed to investigate the expression pattern and the prognostic value of B3GNT3 in patients with early-stage cervical cancer.

METHODS

The mRNA and protein levels of B3GNT3 expression were examined in eight cervical cancer cell lines and ten paired cervical cancer tumors, using real-time PCR and western blotting, respectively. Immunohistochemistry (IHC) was used to analyze B3GNT3 protein expression in paraffin-embedded tissues from 196 early-stage cervical cancer patients. Statistical analyses were applied to evaluate the association between B3GNT3 expression scores and clinical parameters, as well as patient survival.

RESULTS

B3GNT3 expression was significantly upregulated in cervical cancer cell lines and lesions compared with normal cells and adjacent noncancerous cervical tissues. In the 196 cases of tested early-stage cervical cancer samples, the B3GNT3 protein level was positively correlated with high risk TYPES of human papillomavirus (HPV) infection (P = 0.026), FIGO stage (P < 0.001), tumor size (P = 0.025), tumor recurrence (P = 0.004), vital status (P < 0.001), concurrent chemotherapy and radiotherapy (P = 0.016), lymphovascular space involvement (P = 0.003) and most importantly, lymph node metastasis (P = 0.003). Patients with high B3GNT3 expression had a shorter overall survival (OS) and disease-free survival (DFS) compared with those with low expression of this protein. Multivariate analysis suggested that B3GNT3 expression is an independent prognostic indicator for cervical cancer patients.

CONCLUSIONS

Our study demonstrated that elevated B3GNT3 expression is associated with pelvic lymph node metastasis and poor outcome in early-stage cervical cancer patients. B3GNT3 may be a novel prognostic marker and therapeutic target for the treatment of cervical cancer.

β3GnT8 plays an important role in CD147 signal transduction as an upstream modulator of MMP production in tumor cells

Aberrant carbohydration by related glycosyl-transferases plays an important role in the progression of cancer. This study focused on the ablity of β-1,3-N-acetyl-glucosaminyltransferase-8 (β3GnT8) to regulate MMP-2 expression through regulation of the CD147 signal transduction pathway in cancer cells. β3GnT8 catalyzes and then extends a polylactosamine chain specifically on β1-6-branched tetraantennary N-glycans. CD147 is a major carrier of β1-6-branched polylactosamine sugars on tumor cells, and the high glycoform of CD147 (HG-CD147) induces matrix metalloproteinase (MMP) production. In the present study, we analyzed β3GnT8 mRNA expression in 6 cancer cell lines (MCF-7, M231, LN229, U87, SGC-7901 and U251). We found that β3GnT8 expression in the LN229, SGC-7901 and U251 cell lines was higher than that in the other cell lines. Therefore, we established β3GnT8-knockdown cell lines derived from the LN229 and SGC-7901 cell lines to examine the level of polylactosamine and CD147 N-glycosylation. In addition, tunicamycin is widely used as an inhibitor of N-linked glycosylation. Hence, various concentrations of tunicamycin were used to treat the cells in order to study its influence on CD147 N-glycosylation and MMP-2 expression. In conclusion, we found that β3GnT8 regulated the level of N-glycans on CD147 and that N-glycosylation of CD147 has an important effect on MMP-2 expression. Our findings suggest that β3GnT8 affects the signal transduction pathway of MMP-2 by altering the N-glycan structure of CD147.

β3GnT8 regulates the metastatic potential of colorectal carcinoma cells by altering the glycosylation of CD147

Aberrant glycosylation of cell surface glycoproteins is commonly associated with the invasion and metastasis of colorectal carcinomas, which can be attributed to the upregulated expression of glycosyltransferases. Therefore, elucidation of glycosyltransferases and their substrates may improve our understanding of their roles in tumor metastasis. β-1,3-N-acetylglucosaminyltransferase-8 (β3GnT8) is a key enzyme that catalyzes the formation of poly-N-acetyllactosamine (polylactosamine) chains on β1,6-branched N-glycans in vitro, which is also involved in tumor invasion. In the present study, we analyzed the expression of β3GnT8 and its product polylactosamine in four human colorectal carcinoma cell lines (LS-174T, SW620, SW480 and LoVo) with different metastatic potential. We found that the levels of β3GnT8 and polylactosamine chains were gradually increased in the colorectal cancer cell lines in a trend from low to high metastatic potential. Notably, a significantly positive relationship between β3GnT8 expression and HG-CD147 was noted in the colorectal cancer cell lines. To further investigate their relationships, exogenous β3GnT8 was introduced into the LS-174T cells, while expression of β3GnT8 was downregulated in the LoVo cells. The overexpression of β3GnT8 in LS-174T cells increased the level of HG-CD147. Conversely, downregulation of β3GnT8 expression in LoVo cells significantly decreased the expression of HG-CD147. HG-CD147 is a major carrier of β1,6-branched polylactosamine sugars; therefore, the regulation of β3GnT8 significantly altered the β1,6-branched polylactosamine structures on CD147. Hence, we suggest that β3GnT8 plays a key role in the metastasis of colorectal cancer cells by altering the β1,6-branched polylactosamine sugars of CD147.

Polypeptide N-acetylgalactosaminyltransferase 2 regulates cellular metastasis-associated behavior in gastric cancer

Aberrant glycosylation of cell surface glycoprotein due to specific alterations of glycosyltransferase activity is usually associated with invasion and metastasis of cancer, particularly of gastric carcinomas. Polypeptide N-acetylgalactosaminyltransferase 2 (ppGalNAc-T2), which catalyzes initiation of mucin-type O-glycosylation, is also involved in tumor migration and invasion. However, a comprehensive understanding of how ppGalNAc-T2 correlates with the metastasic potential of human gastric cancer is not currently available. In the present study, ppGalNAc-T2 was detected in a variety of human poorly differentiated tumor cells, and expression appeared to be higher in SGC7901 gastric cancer cells. In addition, we investigated the potential effects of ppGalNAc-T2 on growth and metastasis-associated behavior in SGC7901 cells after stable transfection with ppGalNAc-T2 sense and antisense vectors. We found that cell proliferation, adhesion and invasion were decreased in ppGalNAc-T2 overexpressed cells but increased in ppGalNAc-T2 downregulated cells. Therefore, we attempted to clarify the mechanisms underlying the anti-metastatic activities of ppGalNAc-T2. Further investigation indicated that overexpression of ppGalNAc-T2 is involved in the inhibition of matrix metalloproteinase (MMP)-2 expression at both the protein and mRNA levels, which may be associated with ppGalNAc-T2 suppressing the expression of transforming growth factor (TGF)-β1. However, it did not exhibit any apparent correlation with MMP-14 expression levels. Our data show the effect of ppGalNAc-T2 on proliferation, adhesion or invasion of SGC7901 gastric cancer cells, suggesting that ppGalNAc-T2 may exert anti-proliferative and anti-metastatic activity through the decrease of MMP-2 and TGF-β1. These results indicate that ppGalNAc‑T2 may be used as a novel therapeutic target for human gastric cancer treatment.

Coexpressing shRNA with fluorescence tags for quantification of cell migration studies

Understanding migration of cells has many implications in human physiology; some examples include developmental biology, healing, immune responses and tissue remodeling. On the other hand, invasive migration by tumor cells is pathological and is a major cause of mortality amongst cancer sufferers. Cell migration assays have been widely used to quantify potentially metastatic genes. In recent years, the use of RNAi has significantly increased the tools available in cell migration research due to its specific gene targeting for knockdown. The inability to ensure 100% transfection/transduction efficiency reduces the sensitivity of cell migration assays because cells not successfully transfected/transduced with the RNAi are also included in the calculations. This study introduces a different experimental setup mathematically expressed in our named normalized relative infected cell count (N-RICC) that analyses cell migration assays by co-expressing retrovirally transduced shRNA with fluorescence tags from a single vector. Vectors transduced into cells are visible under fluorescence, thus alleviating the problems involved with transduction efficiency by individually identifying cells with targeted genes. Designed shRNAs were targeted against a list of potentially metastatic genes in a highly migratory breast cancer cell line model, MDA-MB-231. We have successfully applied N-RICC analysis to show greater sensitivity of integrin alpha5 (ITGA5) and Ras homologue A (RhoA) in cell metastasis over conventional methods in scratch-wound assays and migration chambers assays.

Are biomarkers correlated with recurrence patterns in patients with resectable gastric adenocarcinoma

The aims of this study are to analyze the failure patterns in radical resected gastric adenocarcinoma, and to evaluate the correlation between recurrence patterns and potentially prognostic factors, including clinical pathological characteristic and biomarkers. Between Jan 2004 and Jun 2006, 84 patients were enrolled into the database analysis, including 8 with clinical stage I, 20 with clinical stage II, 21 with clinical stage IIIA, 22 with clinical stage IIIB and 13 with clinical stage IV, male 61 and female 23. The collected biomarkers including: preoperative tumor markers: CEA, AFP, CA199, CA50, CA72-4 and CA24-2; postoperative immunohistochemical (IHC) markers: Bax, Bcl-2, P27, CyclinD1, TOPO2, MDR, GST-π, Ki67, epidermal growth factor receptor (EGFR), P21, P53, proliferating cell nuclear antigen (PCNA), C-myc and Neu. Three-year local control rate (LCR), disease-free survival (DFS) and over-all survival (OS) were 66, 61 and 64% respectively. Logistic regression analysis showed cyclinD1 and CEA were correlated with prognosis; cyclinD1, CEA were correlated with loco-regional recurrence; PCNA was correlated with remote metastasis; bcl-2, ki67, c-myc2 and Neu were correlated with lymph node metastasis. The present study indicate that patterns of recurrence are variable and may be associated with specific biomarkers, in addition, high level of CEA and low-expressed of cyclinD1 resulted in poor prognosis.