Expression ofN-Acetylglucosaminyltransferase V Is Associated with Prognosis and Histology in Non-Small Cell Lung Cancers

Glycosylated proteins with abnormal glycosylation changes are potential biomarkers for early diagnosis of breast cancer

Conventional cancer management relies on tumor type and stage for diagnosis and treatment, which leads to recurrence and metastasis and death in young women. Early detection of proteins in the serum aids diagnosis, progression, and clinical outcomes, possibly improving survival rate of breast cancer patients. In this review, we provided an insight into the influence of aberrant glycosylation on breast cancer development and progression. Examined literatures revealed that mechanisms underlying glycosylation moieties alteration could enhance early detection, monitoring, and therapeutic efficacy in breast cancer patients. This would serve as a guide for the development of new serum biomarkers with higher sensitivity and specificity, providing possible serological biomarkers for breast cancer diagnosis, progression, and treatment.

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.

Abnormal sialylation and fucosylation of saliva glycoproteins: Characteristics of lung cancer-specific biomarkers

Dysregulated surface glycoproteins play an important role in tumor cell proliferation and progression. Abnormal glycosylation of these glycoproteins may activate tumor signal transduction and lead to tumor development. The tumor microenvironment alters its molecular composition, some of which regulate protein glycosylation biosynthesis. The glycosylation of saliva proteins in lung cancer patients is different from healthy controls, in which the glycans of cancer patients are highly sialylated and hyperfucosylated. Most studies have shown that O-glycans from cancer are truncated O-glycans, while N-glycans contain fucoses and sialic acids. Because glycosylation analysis is challenging, there are few reports on how glycosylation of saliva proteins is related to the occurrence or progression of lung cancer. In this review, we discussed glycoenzymes involved in protein glycosylation, their changes in tumor microenvironment, potential tumor biomarkers present in body fluids, and abnormal glycosylation of saliva or lung glycoproteins. We further explored the effect of glycosylation changes on tumor signal transduction, and emphasized the role of receptor tyrosine kinases in tumorigenesis and metastasis.

The polymorphisms of FGFR2 and MGAT5 affect the susceptibility to COPD in the Chinese people

Background

Chronic obstructive pulmonary disease (COPD) is characterized by incomplete reversible airflow limitation and chronic inflammatory response lesions. This study mainly explored whether FGFR2 and MGAT5 polymorphisms affected the risk of COPD in the Chinese people.

Methods

Five variants in FGFR2 and MGAT5 were chosen and genotyped using Agena MassARRAY platform from 315 COPD patients and 314 healthy controls. The correlation of FGFR2 and MGAT5 with COPD susceptibility was evaluated with odds ratio (OR) and 95% confidence interval (CI) via logistic regression.

Results

We found rs2420915 enhanced the risk of COPD, while rs6430491, rs2593704 reduced the susceptibility of COPD (p < 0.05). Rs2420915 could promote the incidence of COPD in the elderly and nonsmokers. Rs1907240 and rs2257129 also increased the susceptibility to COPD in nonsmokers (p < 0.05). MGAT5-rs2593704 played a protective role in COPD development in different subgroups (age ≤ 70, male, smokers, and individuals with BMI ≤ 24 kg/m²). Meanwhile, rs6430491 was linked with a lower risk of COPD in nonsmoking and BMI ≤ 24 kg/m² subgroups.

Conclusions

We concluded that FGFR2 and MGAT5 genetic polymorphisms are correlated with the risk of COPD in the Chinese people. These data underscored the important role of FGFR2 and MGAT5 gene in the occurrence of COPD and provided new biomarkers for COPD treatment.

Trial registration: NA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01498-3.

Glycosylation in lymphoma: Biology and glycotherapy

Research using mouse lymphoma cell lines has resulted in many reports of glycosylation being a key regulator for the distant metastasis of mouse lymphoma cells in animal models. In contrast, there are only a few reports of experiments examining human lymphoma cell metastasis. The glycosylation pattern in human lymphoma shows that loss of Phaseolus vulgaris leukoagglutinating lectin (L-PHA) reactive oligosaccharides, and sialylation of L-PHA reactive oligosaccharides, are closely associated with a worse prognosis for diffuse large B cell lymphoma (DLBCL) patients. Sialic acid is related to cell adhesion to the extracellular matrix and metastasis of HBL-8 Burkitt lymphoma cells in a severe combined immunodeficiency (SCID) mouse animal model. In HBL-8 clones, differential cell surface sialylation was due to different expression levels of UDP-GlcNAc 2-epimerase (GNE). Knockdown of beta-galactoside alpha-2,6-sialyltransferase (ST6Gal1) resulted in enhanced lymphoma cell adhesion to galectin-1 in anaplastic large cell lymphoma cell line, H-ALCL. A fluorinated sialic acid analogue was shown to be useful for inhibiting sialyltransferase and may provide a new glycoengineering strategy for desialylation, as well as inhibiting invasion and metastasis and inducing cell death in lymphoma cell lines. This paper discusses glycosylation and sialylation in human lymphoma, and several glycoengineering therapeutic strategies for lymphoma.

N-Acetylglucosaminyltransferase III (GnT-III) but not N-Acetylgalactosaminyltransferase-6 and 8 are Differentially Expressed in Invasive and In Situ Ductal Carcinoma of the Breast

Mammary carcinoma is the most common malignant tumor in women, and it is the leading cause of mortality. In tumor context, glycosylation promotes post translational modifications necessary for cell progression, emerging as a relevant tumor hallmarker. This study aimed to analyze the association between polypeptide N-acetylgalactosaminyltransferase-6 (ppGalNAc-T6), -T8, N-acetylglucosaminyltransferase III (GnT-III) expression, Phaseolus vulgaris-leucoagglutinin (PHA-L), wheat germ agglutinin (WGA) and peanut agglutinin (PNA) staining with clinic-histopathological factors from patients with pure ductal carcinoma in situ (DCIS) and DCIS with invasive ductal carcinoma (DCIS-IDC) of breast. Formalin-fixed and paraffin-embedded samples (n = 109) were analyzed. In pure DCIS samples GnT-III was over-expressed in comedo lesions (p = 0.007). In DCIS-IDC, GnT-III expression was associated with high nuclear grade tumors (p = 0.039) while the presence of PHA-L and WGA were inversely related to HER-2 expression (p = 0.001; p = 0.036, respectively). These findings pointed to possible involvement of GnT-III, ppGalNAc-T8, L-PHA and WGA as probes in prognostic evaluation of DCIS.

Protein glycosylation in cancers and its potential therapeutic applications in neuroblastoma

Glycosylation is the most complex post-translational modification of proteins. Altered glycans on the tumor- and host-cell surface and in the tumor microenvironment have been identified to mediate critical events in cancer pathogenesis and progression. Tumor-associated glycan changes comprise increased branching of N-glycans, higher density of O-glycans, generation of truncated versions of normal counterparts, and generation of unusual forms of terminal structures arising from sialylation and fucosylation. The functional role of tumor-associated glycans (Tn, sTn, T, and sLe^a/x) is dependent on the interaction with lectins. Lectins are expressed on the surface of immune cells and endothelial cells or exist as extracellular matrix proteins and soluble adhesion molecules. Expression of tumor-associated glycans is involved in the dysregulation of glycogenes, which mainly comprise glycosyltransferases and glycosidases. Furthermore, genetic and epigenetic mechanisms on many glycogenes are associated with malignant transformation. With better understanding of all aspects of cancer-cell glycomics, many tumor-associated glycans have been utilized for diagnostic, prognostic, and therapeutic purposes. Glycan-based therapeutics has been applied to cancers from breast, lung, gastrointestinal system, melanomas, and lymphomas but rarely to neuroblastomas (NBs). The success of anti-disialoganglioside (GD2, a glycolipid antigen) antibodies sheds light on glycan-based therapies for NB and also suggests the possibility of protein glycosylation-based therapies for NB. This review summarizes our understanding of cancer glycobiology with a focus of how protein glycosylation and associated glycosyltransferases affect cellular behaviors and treatment outcome of various cancers, especially NB. Finally, we highlight potential applications of glycosylation in drug and cancer vaccine development for NB.

Core-fucosylation plays a pivotal role in hepatitis B pseudo virus infection: a possible implication for HBV glycotherapy

The functions of cell surface proteins, such as growth factor receptors and virus/bacteria-entry receptors, can be dynamically regulated by oligosaccharide modifications. In the present study, we investigated the involvement of glycosylation in hepatitis B virus (HBV) entry into hepatoma cells. Infection of oligosaccharide-remodeling hepatoma cells with a pseudo virus of HBV, bio-nanocapsule (BNC), was evaluated by flow cytometry and confocal microscopy. Among various experiments using several hepatoma cells, marked difference was observed between Huh6 cells and HB611 cells, which were established by HBV gene transfection into hepatoma cells. Comprehensive oligosaccharide analysis showed dramatic increases of core fucosylation in HB611 cells, compared with Huh6 cells. Knock down of fucosyltransferase 8 (FUT8) reduced BNC entry into HB611 cells. In contrast, overexpression of FUT8 in Huh6 cells increased BNC entry. Although expression of sodium taurocholate cotransporting polypeptide (NTCP), which is one of HBV receptors was very similar between Huh6 and HB611 cells, proteins coprecipitated with NTCP were dependent on levels of core-fucosylation, suggesting that core-fucosylation regulates BNC entry into hepatoma cells. Our findings demonstrate that core-fucosylation is an important glycosylation for HBV infection of hepatoma cells through HBV-receptor-mediated endocytosis. Down-regulation of core-fucosylation may be a novel target for HBV therapy.

β1,6-N-acetylglucosaminyltransferase V predicts recurrence and survival of patients with clear-cell renal cell carcinoma after surgical resection

PURPOSE

β1,6-N-acetylglucosaminyltransferase V (MGAT5), which is required for the biosynthesis of β1,6GlcNAc-branched N-linked glycans attached to cell surface and secreted glycoproteins, accounts for oncogenic growth signal transduction during the development and progression of various malignancies. Our present study aimed to evaluate the impact of MGAT5 expression on recurrence and survival of patients with clear-cell renal cell carcinoma (ccRCC) following surgery.

METHODS

We retrospectively enrolled 265 patients (196 in the training cohort and 69 in the validation cohort) with ccRCC undergoing nephrectomy at a single institution. Clinicopathologic features, overall survival (OS) and recurrence-free survival (RFS) were recorded. MGAT5 intensities were assessed by immunohistochemistry in specimens of patients. Kaplan-Meier method was applied to compare survival curves. Cox regression models were used to analyze the impact of prognostic factors on OS and RFS. Concordance index (C-index) was calculated to assess predictive accuracy.

RESULTS

In both cohorts, MGAT5 expression positively correlated with metastatic and advanced TNM stage. High MGAT5 expression indicated poor survival (P < 0.001 in training set and P < 0.001 in validation set) and early recurrence (P < 0.001 in training set and P = 0.004 in validation set) of patients with ccRCC. After multivariate Cox regression analysis, MGAT5 expression was identified as an independent adverse prognostic factor for survival and recurrence. The predictive accuracy of TNM, UISS and SSIGN prognostic models was improved when MGAT5 expression was added.

CONCLUSIONS

MGAT5 expression is a potential independent adverse prognostic biomarker for recurrence and survival of patients with ccRCC after nephrectomy.

Effect of GnT-V knockdown on the proliferation, migration and invasion of the SMMC7721/R human hepatocellular carcinoma drug-resistant cell line

Hepatocellular carcinoma (HCC) is a commonly occurring malignant tumor, with a high incidence rate. The present study aimed to investigate the effect of knocking down the N‑glycosyltransferase‑V (GnT‑V) protein on the proliferation, migration and invasion of the human HCC drug‑resistant cell line, SMMC7721/R. SMMC7721/R cells with GnT‑V‑knockdown (SMMC‑7721/R‑GnT‑V) were constructed using the method of lentiviral transfection. The expression of GnT‑V was assessed using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blotting. Cell proliferation was determined using an MTT assay, and the extent of cellular apoptosis was assessed using flow cytometric analysis. Additionally, the metastatic ability of the cells in vitro was analyzed using cell adhesion and invasion assays. Western blotting was used to investigate the protein expression levels of caspase‑3, caspase‑9, Bcl‑2, Bax, matrix metalloproteinase (MMP)‑2 and MMP‑9, and RT‑qPCR was used to determine the mRNA expression levels of the genes for the breast cancer resistance protein and P‑glycoprotein in the SMMC‑7721/R cells. Taken together, the results of the present study revealed that the knockdown of GnT‑V significantly suppressed the proliferation, migration and invasion (P<0.05) of the SMMC‑7721/R cells. Furthermore, the possible mechanism underlying these phenomena may be associated with the induction of mitochondria‑mediated apoptosis, inhibition of the degradation of the extracellular matrix and an enhancement of the drug-sensitivity. GnT‑V‑knockdown may therefore be used to treat drug‑resistant HCC in the future.

N-acetylglucosaminyltransferase V modulates radiosensitivity and migration of small cell lung cancer through epithelial-mesenchymal transition

N-acetylglucosaminyltransferase V (Gnt-V) has been linked to the migration of various human cancers. Recently we have found that inhibition of Gnt-V increases the radiosensitivity of cancer cells. However, the mechanisms by which Gnt-V mediates radiosensitivity and migration, especially in small cell lung cancer (SCLC) remain unknown. In our study, two SCLC cell lines (H1688 and H146) were used to investigate whether Gnt-V modulated the radiosensitivity and migration of SCLC cells through the epithelial-mesenchymal transition (EMT). The results showed that the expression of Gnt-V correlated with the N stage in patients with SCLC. Overexpression of Gnt-V led to a further increase in the relative viable cell number and survival fraction with a decrease in apoptosis rate and Bax/Bcl-2 ratio, when the cells were treated with irradiation. By contrast, knockdown of Gnt-V with irradiation resulted in a further decrease in the relative viable cell number and survival fraction but an increase in apoptosis rate and Bax/Bcl-2 ratio. Cells expressing high levels of Gnt-V increased migration whereas low levels of Gnt-V suppressed cell migration. Besides, the transient knockdown of ZEB2 led to an increase in radiosensitivity and an inhibition in the migration of SCLC cells. Furthermore, Gnt-V was negatively correlated with E-cadherin expression but positively correlated with N-cadherin, vimentin and ZEB2 expression. Finally, an in vivo study revealed that upregulation of Gnt-V caused tumour growth more quickly, as well as the expression of EMT-related markers (N-cadherin, vimentin and ZEB2). Taken together, the study suggested that an elevation of Gnt-V could lead to the radiosensitivity and migration of SCLC cells by inducing EMT, thereby highlighting Gnt-V as a potential therapeutic target for the prevention of EMT-associated tumour radioresistance and migration.

Glycans and cancer: role of N-glycans in cancer biomarker, progression and metastasis, and therapeutics

Glycosylation is catalyzed by various glycosyltransferase enzymes which are mostly located in the Golgi apparatus in cells. These enzymes glycosylate various complex carbohydrates such as glycoproteins, glycolipids, and proteoglycans. The enzyme activity of glycosyltransferases and their gene expression are altered in various pathophysiological situations including cancer. Furthermore, the activity of glycosyltransferases is controlled by various factors such as the levels of nucleotide sugars, acceptor substrates, nucleotide sugar transporters, chaperons, and endogenous lectin in cancer cells. The glycosylation results in various functional changes of glycoproteins including cell surface receptors and adhesion molecules such as E-cadherin and integrins. These changes confer the unique characteristic phenotypes associated with cancer cells. Therefore, glycans play key roles in cancer progression and treatment. This review focuses on glycan structures, their biosynthetic glycosyltransferases, and their genes in relation to their biological significance and involvement in cancer, especially cancer biomarkers, epithelial-mesenchymal transition, cancer progression and metastasis, and therapeutics. Major N-glycan branching structures which are directly related to cancer are β1,6-GlcNAc branching, bisecting GlcNAc, and core fucose. These structures are enzymatic products of glycosyltransferases, GnT-V, GnT-III, and Fut8, respectively. The genes encoding these enzymes are designated as MGAT5 (Mgat5), MGAT3 (Mgat3), and FUT8 (Fut8) in humans (mice in parenthesis), respectively. GnT-V is highly associated with cancer metastasis, whereas GnT-III is associated with cancer suppression. Fut8 is involved in expression of cancer biomarker as well as in the treatment of cancer. In addition to these enzymes, GnT-IV and GnT-IX (GnT-Vb) will be also discussed in relation to cancer.

Glycosylation alterations in lung and brain cancer

Alterations in glycosylation are common in cancer and are thought to contribute to disease. Lung cancer and primary malignant brain cancer, most commonly glioblastoma, are genetically heterogeneous diseases with extremely poor prognoses. In this review, we summarize the data demonstrating that glycosylation is altered in lung and brain cancer. We then use specific examples to highlight the diverse roles of glycosylation in these two deadly diseases and illustrate shared mechanisms of oncogenesis. In addition to alterations in glycoconjugate biosynthesis, we also discuss mechanisms of postsynthetic glycan modification in cancer. We suggest that alterations in glycosylation in lung and brain cancer provide novel tumor biomarkers and therapeutic targets.

Expression of fucosyltransferase 8 is associated with an unfavorable clinical outcome in non-small cell lung cancers

Objecitive: Fucosyltransferase 8 (FUT8), the only enzyme responsible for the core α1,6-fucosylation of asparagine-linked oligosaccharides of glycoproteins, is a vital enzyme in cancer development and progression. We examined FUT8 expression in non-small cell lung cancers (NSCLCs) to analyze its clinical significance. We also examined the expression of guanosine diphosphate-mannose-4,6-dehydratase (GMD), which is imperative for the synthesis of fucosylated oligosaccharides.

METHODS

Using immunohistochemistry, we evaluated the expression of FUT8 and GMD in relation to patient survival and prognosis in potentially curatively resected NSCLCs.

RESULTS

High expression of FUT8 was found in 67 of 129 NSCLCs (51.9%) and was significantly found in non-squamous cell carcinomas (p = 0.008). High expression of FUT8 was associated with poor survival (p = 0.03) and was also a significant and independent unfavorable prognostic factor in patients with potentially curatively resected NSCLCs (p = 0.047). High expression of GMD was significantly associated with high FUT8 expression (p = 0.04).

CONCLUSIONS

High expression of FUT8 is associated with an unfavorable clinical outcome in patients with potentially curatively resected NSCLCs, suggesting that FUT8 can be a prognostic factor. The analysis of FUT8 expression and its core fucosylated products may provide new insights for the therapeutic targets of NSCLCs.

Altered β1,6-GlcNAc branched N-glycans impair TGF-β-mediated epithelial-to-mesenchymal transition through Smad signalling pathway in human lung cancer

The change of oligosaccharide structure has been revealed to be crucial for glycoproteins' biological functions and cell biological characteristics. N-acetylglucosaminy transferase V (GnT-V), a key enzyme catalysing the reaction of adding β1, 6-N-acetylglucosamine (GlcNAc) on asparagine-linked oligosaccharides of cell proteins, has been implicated to a metastastic-promoting oncoprotein in some carcinomas. However, this correlation might not be subjected to all types of cancers, for example, in non-small cell lung cancers, low level of GnT-V expression is associated with relatively short survival time and poor prognosis. To explain the role of GnT-V in lung cancer progression, we studied the association of GnT-V expression with lung cancer EMT behaviour. We found that GnT-V expression was correlated with epithelial marker positively and mesenchymal marker negatively. GnT-V levels, as well as β1,6-GlcNAc branched N-glycans, were strongly reduced in TGF-β1-induced EMT of human lung adenocarcinoma A549 cells. Further studies showed that suppression of β1,6-GlcNAc branched N-glycans by inhibitor or GnT-V silencing in A549 cells could promote TGF-β1-induced EMT-like changes, cell migration and invasion. Meanwhile, overexpression of GnT-V impaired TGF-β1-induced EMT, migration and invasion. It suggests that GnT-V suppresses the EMT process of lung cancer cells through inhibiting the TGF-β/Smad signalling and its downstream transcription factors in a GnT-V catalytic activity–dependent manner. Taken together, the present study reveals a novel mechanism of GnT-V as a suppressor of both EMT and invasion in human lung cancer cells, which may be useful for fully understanding N-glycan's biological roles in lung cancer progression.

Glycobiology of neuroblastoma: impact on tumor behavior, prognosis, and therapeutic strategies

Neuroblastoma (NB), accounting for 10% of childhood cancers, exhibits aberrant cell-surface glycosylation patterns. There is evidence that changes in glycolipids and protein glycosylation pathways are associated to NB biological behavior. Polysialic acid (PSA) interferes with cellular adhesion, and correlates with NB progression and poor prognosis, as well as the expression of sialyltransferase STX, the key enzyme responsible for PSA synthesis. Galectin-1 and gangliosides, overexpressed and actively shedded by tumor cells, can modulate normal cells present in the tumor microenvironment, favoring angiogenesis and immunological escape. Different glycosyltransferases are emerging as tumor markers and potential molecular targets. Immunotherapy targeting disialoganglioside GD2 rises as an important treatment option. One anti-GD2 antibody (ch14.18), combined with IL-2 and GM-CSF, significantly improves survival for high-risk NB patients. This review summarizes our current knowledge on NB glycobiology, highlighting the molecular basis by which carbohydrates and protein–carbohydrate interactions impact on biological behavior and patient clinical outcome.

Expression of N-acetylglucosaminyltransferase V in the subserosal layer correlates with postsurgical survival of pathological tumor stage 2 carcinoma of the gallbladder

BACKGROUND

N-Acetylglucosaminyltransferase V (GnT-V), an enzyme that catalyzes the β1-6 branching of N-acetylglucosamine on asparagine-linked oligosaccharides of cellular proteins, enhances the malignant behaviors of carcinoma cells in experimental models. The aim of this study was to determine clinical significance of GnT-V expression in human pT2 gallbladder carcinoma with simple in vitro experiments.

METHODS

Ninety patients with pT2 gallbladder carcinoma were included for this study. The in vitro and in vivo biological effects of GnT-V were investigated using gallbladder carcinoma cells with variable GnT-V expression levels induced by a small interfering RNA.

RESULTS

Of the 90 cases, 57 showed positive staining and the remaining 33 demonstrated negative staining, the subcellular localization in the 57 cases was classified into the granular-type in 31 cases and the diffuse-type in 26 cases. In 76 cases with curative resection, postsurgical survival was significantly poorer in those showing positive staining than in those showing negative staining (P = 0.028). In all of the 76 cases, postsurgical recurrence was significantly more frequent in those showing diffuse-type localization than in those showing negative staining. Experimental analyses demonstrated that the down-regulation of GnT-V expression in gallbladder carcinoma cells induced suppression of cell growth in vitro. The expression levels of GnT-V in the cells were highly correlated with the rapid in vivo growth coupled with the enhanced angiogenesis, and the tendency to form liver metastasis.

CONCLUSIONS

GnT-V expression in the subserosal layer of pT2 gallbladder carcinoma is correlated with the aggressiveness of the disease.

Recent progress and new perspectives in lymphoma glycobiology

Glycosylation has recently become one of the most significant subjects in tumor biology, and cell surface glycosylation is closely associated with various biological phenomena in tumor cells. However, the biological significance of cell surface glycosylation and sialic acid linked to glycans in human malignant lymphoma is not well elucidated. We have determined that 1) sialylation or loss of N-glycosylation is closely associated with a worse prognosis in human diffuse large B-cell lymphoma (DLBCL), and 2) glycosylation or sialic acid on the surface of lymphoma cells plays significant roles in cell adhesion or invasion to the extracellular matrix, cell growth, apoptosis and cell death. In the present review, the biological functions of glycosylation or sialic acid in human malignant lymphoma are discussed.

Expression of HAb18G in non-small lung cancer and characterization of activation, migration, proliferation, and apoptosis in A549 cells following siRNA-induced downregulation of HAb18G

HAb18G, a novel cancer biomarker, has been shown to be involved in the progression of malignancy by regulating expression of vascular endothelial growth factor (VEGF) and matrixmetalloproteinases (MMPs). The goal of this study was to evaluate the role of HAb18G in the biology of NSCLC and to determine its potential as a therapeutic target. HAb18G protein expression was detected by immunohistochemistry in 150 NSCLC tissues. The results showed that HAb18G protein expression was associated with tumor diameter, lymph node status, tumor stage, and poor prognosis (P < 0.05). Multivariate analysis showed that HAb18G overexpression was an independent prognostic factor (HR, 3.713; 95 % CI, 1.114-12.373; P = 0.033). Transient infection of A549 lung cancer cells with small interfering RNA (SiRNA) against HAb18G efficiently inhibited the expression of HAb18G in A549 lung cancer cells at both mRNA and protein levels. Downregulation of HAb18G not only reduced MMP-2, MMP-9, and VEGF at mRNA and protein levels in A549 cells, but also inhibited fibroblasts to secrete MMP-2 and MMP-9 at mRNA level. Additionally, downregulation of HAb18G mRNA resulted in decreased migration, proliferation, and increased apoptosis of A549 in vitro. Our findings suggest that HAb18G overexpression plays an important role in progression of NSCLC and HAb18G may be a potential target of NSCLC therapy.

Clinical and prognostic implications of β1, 6-N-acetylglucosaminyltransferase V in patients with gastric cancer

Aberrant β1, 6-N-acetylglucosaminyltransferase V (MGAT5) expression in malignant tissues has been reported to be involved in the development of various cancers and their progression, through altering N-glycan branching. We aimed to investigate the clinical and prognostic values of MGAT5 and improve the risk stratification in patients with gastric cancer. MGAT5 expression was retrospectively analyzed by immunohistochemistry in three independent sets comprising 313 patients from China with gastric adenocarcinoma. Results were assessed for association with clinical features and overall survival using Kaplan-Meier analysis. Prognostic values of MGAT5 expression and clinical outcomes were evaluated by Cox regression analysis. A molecular prognostic stratification scheme incorporating MGAT5 expression was determined in patients with late-stage gastric cancer by using receiver operating characteristic analysis. The results show that low intratumoral MGAT5 density, which was associated with poor differentiation, N classification, TNM stage, and Kiel stage, was an independent prognosticator for poor overall survival. The combination of intratumoral MGAT5 expression and TNM or Kiel staging systems had a better predictive power for overall survival. Applying the prognostic value of intratumoral MGAT5 density to TNM stage III+IV and Kiel stage IIIB+IV groups showed a better risk stratification for overall survival in patients with late-stage gastric cancer. In conclusion, integrating intratumoral MGAT5 density that was recognized as an independent prognostic marker into current clinical staging systems significantly improved prognostic stratification of patients with late-stage gastric cancer. This refined risk stratification scheme might aid in appropriate therapeutic options and ultimately improve the outcomes of patients with advanced-stage disease.

The role of N-acetylglucosaminyltransferases V in the malignancy of human hepatocellular carcinoma

To investigate the role of N-acetylglucosaminyltransferases V (GnT-V) in the malignancy of human hepatocellular carcinoma (HCC), the GnT-V stably suppressed cell line HepG2 GnT-V/1564 was constructed from HepG2. The proliferation, migration, invasion, metastasis of HepG2 GnT-V/1564 was investigated both in vitro and in vivo. The clinical pathological significance of GnT-V expression was also studied in 140 cases of HCC tissues. This study showed that down-regulation of GnT-V inhibited the proliferation, migration and invasion of the HepG2 cells. In addition, GnT-V expression was shown in 138 cases of 140 (98.6%) HCC samples, in 3 cases of 31 (9.7%) in liver cirrhosis cases and in 1 cases of 20 (5.0%) in normal liver tissues. Besides, a higher level of GnT-V was observed more frequently in the advanced tumors with higher T stage and histological grade. These data suggested that GnT-V expression was positively related with malignancy in HCC and GnT-V may be both a differentiation marker and a potential target for the treatment of HCC.

Enhanced epithelial-mesenchymal transition-like phenotype in N-acetylglucosaminyltransferase V transgenic mouse skin promotes wound healing

N-Acetylglucosaminyltransferase V (GnT-V) catalyzes the β1,6 branching of N-acetylglucosamine on N-glycans. GnT-V expression is elevated during malignant transformation in various types of cancer. However, the mechanism by which GnT-V promotes cancer progression is unclear. To characterize the biological significance of GnT-V, we established GnT-V transgenic (Tg) mice, in which GnT-V is regulated by a β-actin promoter. No spontaneous cancer was detected in any organs of the GnT-V Tg mice. However, GnT-V expression was up-regulated in GnT-V Tg mouse skin, and cultured keratinocytes derived from these mice showed enhanced migration, which was associated with changes in E-cadherin localization and epithelial-mesenchymal transition (EMT). Further, EMT-associated factors snail, twist, and N-cadherin were up-regulated, and cutaneous wound healing was accelerated in vivo. We further investigated the detailed mechanisms of EMT by assessing EGF signaling and found up-regulated EGF receptor signaling in GnT-V Tg mouse keratinocytes. These findings indicate that GnT-V overexpression promotes EMT and keratinocyte migration in part through enhanced EGF receptor signaling.

The cancer cell--leukocyte fusion theory of metastasis

The cause of metastasis remains elusive despite vast information on cancer cells. We posit that cancer cell fusion with macrophages or other migratory bone marrow-derived cells (BMDCs) provides an explanation. BMDCs fused with tumor cells were present in animal tumor xenografts where they were associated with metastases. In myeloma patients, transcriptionally active myeloma nuclei were incorporated into osteoclasts through fusion. In patients with renal cell carcinoma arising poststem cell transplant, donor genes were incorporated in recipient cancer cell nuclei, most likely through fusion, and showed tumor distribution patterns characteristic of cancer stem cells. Melanoma-macrophage hybrids generated in vitro contained chromosomes from both parental partners, showed increased ploidy, and transcribed and translated genes from both parents. They exhibited chemotactic migration in vitro toward fibronectin and exhibited high frequencies of metastasis when implanted in mice. They produced macromolecules that are characteristic of macrophages and known indicators of metastasis (c-Met, SPARC, MCR1, GnT-V, and the integrin subunits alpha(3), alpha(5), alpha(6), alpha(v), beta(1), beta(3)). They also produced high levels of beta1,6-branched oligosaccharides-predictors of poor survival in patients with melanoma or carcinomas of the breast, lung, and colon. We thus hypothesize that such gene expression patterns in cancer are generated through fusion. Tumor hybrids also showed active autophagy, a characteristic of both metastatic cancers and macrophages. BMDC-tumor cell fusion explains epidermal-mesenchymal transition in cancer since BMDCs express mesodermal traits and epithelial-mesenchymal transition regulators (Twist, SPARC, and others). If BMDC-tumor cell fusion underlies invasion and metastasis in human cancer, new approaches for therapeutic intervention would be mandated.

Fusion of tumour cells with bone marrow-derived cells: a unifying explanation for metastasis

The causes of metastasis remain elusive despite vast information on cancer cells. We posit that cancer cell fusion with macrophages or other migratory bone marrow-derived cells (BMDCs) provides an explanation. BMDC-tumour hybrids have been detected in numerous animal models and recently in human cancer. Molecular studies indicate that gene expression in such hybrids reflects a metastatic phenotype. Should BMDC-tumour fusion be found to underlie invasion and metastasis in human cancer, new approaches for therapy would surely follow.

Inverse correlation between the extent of N-glycan branching and intercellular adhesion in epithelia. Contribution of the Na,K-ATPase beta1 subunit

The majority of cell adhesion molecules are N-glycosylated, but the role of N-glycans in intercellular adhesion in epithelia remains ill-defined. Reducing N-glycan branching of cellular glycoproteins by swainsonine, the inhibitor of N-glycan processing, tightens and stabilizes cell-cell junctions as detected by a 3-fold decrease in the paracellular permeability and a 2-3-fold increase in the resistance of the adherens junction proteins to extraction by non-ionic detergent. In addition, exposure of cells to swainsonine inhibits motility of MDCK cells. Mutagenic removal of N-glycosylation sites from the Na,K-ATPase beta(1) subunit impairs cell-cell adhesion and decreases the effect of swainsonine on the paracellular permeability of the cell monolayer and also on detergent resistance of adherens junction proteins, indicating that the extent of N-glycan branching of this subunit is important for intercellular adhesion. The N-glycans of the Na,K-ATPase beta(1) subunit and E-cadherin are less complex in tight renal epithelia than in the leakier intestinal epithelium. The complexity of the N-glycans linked to these proteins gradually decreases upon the formation of a tight monolayer from dispersed MDCK cells. This correlates with a cell-cell adhesion-induced increase in expression of GnT-III (stops N-glycan branching) and a decrease in expression of GnTs IVC and V (promote N-glycan branching) as detected by real-time quantitative PCR. Consistent with these results, partial silencing of the gene encoding GnT-III increases branching of N-glycans linked to the Na,K-ATPase beta(1) subunit and other glycoproteins and results in a 2-fold increase in the paracellular permeability of MDCK cell monolayers. These results suggest epithelial cells can regulate tightness of cell junctions via remodeling of N-glycans, including those linked to the Na,K-ATPase beta(1)-subunit.

Expression of N-acetylglucosaminyltransferase V in endometrial cancer correlates with poor prognosis

N-acetylglucosaminyltransferase V (GnT-V) is an enzyme that catalyses β1–6 branching of N-acetylglucosamine on asparagine-linked oligosaccharides of cell proteins. The present study aimed to investigate GnT-V expression and its prognostic significance in endometrial cancer. N-acetylglucosaminyltransferase V expression was studied by immunohistochemistry in 74 surgically resected endometrial cancers, and the staining intensity was evaluated. High GnT-V expression in tumour cells was found in 43 (58.1%) of the 74 cases, and was positively correlated with advanced patient age, histological grade, and lymph vascular space involvement. Patients with high GnT-V expression had significantly impaired overall survival and progression-free survival (PFS) (P=0.0041 and P=0.0023, respectively) compared to patients with low expression of GnT-V. On multivariate analysis, GnT-V expression was an independent prognostic factor for PFS (P=0.0364). β1–6 branching of asparagine-linked oligosaccharides was also detected in GnT-V-positive endometrial cancer cells by leukoagglutinating phytohaemagglutinin (L₄-PHA) staining, and the molecular size of the major glycoproteins recognised by L₄-PHA was approximately 60–200 kDa by lectin blot analysis. These results suggested that high GnT-V expression was correlated with an unfavourable clinical outcome, and that GnT-V is involved in the malignant potential of endometrial cancer by increasing the synthesis of β1–6 branching of asparagine-linked oligosaccharides.

Melanophages reside in hypermelanotic, aberrantly glycosylated tumor areas and predict improved outcome in primary cutaneous malignant melanoma

BACKGROUND

Previously, hypermelanotic regions of cutaneous malignant melanoma (CMM) were found to contain a mixture of highly melanized melanoma cells and melanophages. Both cell types produced beta1,6-branched oligosaccharides. These sugars are used for motility by myeloid cells and cancer cells alike and are associated with poor survival in carcinomas of the breast, colon and lung. This study further investigated associations between melanophages and beta1,6-branched oligosaccharides and their potential contributions to patient outcome.

METHODS

Individual archival melanomas and high-throughput melanoma tissue microarrays were stained for melanophages with azure blue/S100 and for beta1,6-branched oligosaccharides with the lectin leukocytic phytohemagglutinin (LPHA, a selective marker for beta1,6-branched oligosaccharides).

RESULTS

In primary CMM, melanophages were highly enriched in hypermelanotic, LPHA-positive tumor regions and correlated with improved outcome at 10- and 20-year follow ups. While the combination of melanophages, LPHA positivity and high pigmentation indicated better outcome, a subset of LPHA-positive cells not associated with melanophages indicated worse outcome.

CONCLUSION

This is the first report of an anti-tumor role for the melanophage in melanoma biology. There appeared to be two classes of beta1,6-branched oligosaccharide-producing melanoma cells with opposing effects on outcome: one that attracted melanophages (better) and another that did not (worse). The findings disclose new aspects of the immune system and aberrant glycosylation in CMM.

Inhibition of a specific N-glycosylation activity results in attenuation of breast carcinoma cell invasiveness-related phenotypes: inhibition of epidermal growth factor-induced dephosphorylation of focal adhesion kinase

Changes in the expression of glycosyltransferases that branch N-linked glycans can alter the function of several types of cell surface receptors and a glucose transporter. To study in detail the mechanisms by which aberrant N-glycosylation caused by altered N-acetylglucosaminyltransferase V(GnT-V, GnT-Va, and Mgat5a) expression can regulate the invasiveness-related phenotypes found in some carcinomas, we utilized specific small interfering RNA (siRNA) to selectively knock down GnT-V expression in the highly metastatic and invasive human breast carcinoma cell line, MDA-MB231. Knockdown of GnT-V by siRNA expression had no effect on epidermal growth factor receptor expression levels but lowered expression of N-linked beta(1,6)-branching on epidermal growth factor receptor, as expected. Compared with control cells, knockdown of GnT-V caused significant inhibition of the morphological changes and cell detachment from matrix that is normally seen after stimulation with epidermal growth factor (EGF). Decreased expression of GnT-V caused a marked inhibition of EGF-induced dephosphorylation of focal adhesion kinase (FAK), consistent with the lack of cell morphology changes in the cells expressing GnT-V siRNA. The attenuation of EGF-mediated phosphorylation and activation of the tyrosine phosphatase SHP-2 was dramatically observed in GnT-V knockdown cells, and these effects could be rescued by reintroduction of GnT-V into these cells, indicating that reduced EGF-mediated activation of SHP-2 was GnT-V related. Concomitantly, knockdown of GnT-V caused reduced EGF-mediated ERK signaling and tumor cell invasiveness-related phenotypes, including effects on actin rearrangement and cell motility. No changes in EGF binding were observed, however, after knockdown of GnT-V. Our results demonstrate that decreased GnT-V activity due to siRNA expression in human breast carcinoma cells resulted in an inhibition of EGF-stimulated SHP-2 activation and, consequently, caused attenuation of the dephosphorylation of FAK induced by EGF. These effects suppressed EGF-mediated downstream signaling and invasiveness-related phenotypes and suggest GnT-V as a potential therapeutic target.

Tumor suppressor p16INK4a--modulator of glycomic profile and galectin-1 expression to increase susceptibility to carbohydrate-dependent induction of anoikis in pancreatic carcinoma cells

Expression of the tumor suppressor p16(INK4a) after stable transfection can restore the susceptibility of epithelial tumor cells to anoikis. This property is linked to increases in the expression and cell-surface presence of the fibronectin receptor. Considering its glycan chains as pivotal signals, we assumed an effect of p16(INK4a) on glycosylation. To test this hypothesis for human Capan-1 pancreatic carcinoma cells, we combined microarray for selected glycosyltransferase genes with 2D chromatographic glycan profiling and plant lectin binding. Major differences between p16-positive and control cells were detected. They concerned expression of beta1,4-galactosyltransferases (down-regulation of beta1,4-galactosyltransferases-I/V and up-regulation of beta1,4-galactosyltransferase-IV) as well as decreased alpha2,3-sialylation of O-glycans and alpha2,6-sialylation of N-glycans. The changes are compatible with increased beta(1)-integrin maturation, subunit assembly and binding activity of the alpha(5)beta(1)-integrin. Of further functional relevance in line with our hypothesis, we revealed differential reactivity towards endogenous lectins, especially galectin-1. As a result of reduced sialylation, the cells' capacity to bind galectin-1 was enhanced. In parallel, the level of transcription of the galectin-1 gene increased conspicuously in p16(INK4a)-positive cells, and even figured prominently in a microarray on 1996 tumor-associated genes and in proteomic analysis. The cells therefore gain optimal responsiveness. The correlation between genetically modulated galectin-1 levels and anoikis rates in engineered transfectants inferred functional significance. To connect these findings to the fibronectin receptor, galectin-1 was shown to be co-immunoprecipitated. We conclude that p16(INK4a) orchestrates distinct aspects of glycosylation that are relevant for integrin maturation and reactivity to an endogenous effector as well as the effector's expression. This mechanism establishes a new aspect of p16(INK4a) functionality.

Mass spectrometry-based "omics" technologies in cancer diagnostics

Many "omics" techniques have been developed for one goal: biomarker discovery and early diagnosis of human cancers. A comprehensive review of mass spectrometry-based "omics" approaches performed on various biological samples for molecular diagnosis of human cancers is presented in this article. Furthermore, the existing and potential problems/solutions (both de facto experimental and bioinformatic challenges), and future prospects have been extensively discussed. Although the use of present omic methods as diagnostic tools are still in their infant stage and consequently not ready for immediate clinical use, it can be envisaged that the "omics"-based cancer diagnostics will gradually enter into the clinic in next 10 years as an important supplement to current clinical diagnostics.

An Interlocker concept of carcinogenesis

A critical feature in the sequence of events occurring during carcinogenesis is the development of irreversibility. The term "Interlocker" is used here to denote a mechanism by which irreversibility is brought about. The presentation focuses on conceptualizations of such processes. Two will be described below.

N-Acetylglucosaminyltransferase V and β1-6 BranchingN-Linked Oligosaccharides Are Associated with Good Prognosis of Patients with Bladder Cancer

PURPOSE

N-acetylglucosaminyltransferase V (GnT-V) is an enzyme that catalyzes beta1-6 branching of N-acetylglucosamine on asparagine (N)-linked oligosaccharides (N-glycan) of cell proteins. We examined the relationship between GnT-V expression and clinicopathologic features of the patients with bladder cancer.

EXPERIMENTAL DESIGN

We immunohistochemically examined GnT-V expression in paraffin-embedded bladder cancer specimen using anti-GnT-V monoclonal antibody. We compared GnT-V expression with cause-specific survival of the patients with bladder cancer treated by radical cystectomy. Kaplan-Meier survival curves were generated to show the cause-specific survival. Univariate and multivariate analyses were carried out to compare GnT-V expression with other clinical and pathologic variables. We also evaluated mRNA expression of GnT-V and N-linked oligosaccharide structure in bladder cancer specimens.

RESULTS

Immunohistochemistry revealed that GnT-V expression inversely correlated with tumor grade and stage. The incidence of positive GnT-V expression in bladder cancer was significantly higher in low-grade/superficial cancer than in high-grade/invasive cancer. The patients whose tumor was positive for GnT-V survived significantly longer than those whose tumor was negative for GnT-V. Univariate and multivariate analyses revealed that GnT-V expression was an independent predictor of prognosis of the patient. The expression of GnT-V mRNA determined by reverse transcription-PCR was consistent with the results with immunohistochemistry for tumor samples. Carbohydrate structural analysis revealed that superficial bladder cancer is rich in branched N-linked oligosaccharides, for which biosynthesis GnT-V is responsible.

CONCLUSIONS

GnT-V and its resultant beta1-6 branching N-linked oligosaccharides are closely related to low malignant potential and good prognosis of the patients with bladder cancer.

Coexpression of beta1,6-N-acetylglucosaminyltransferase V glycoprotein substrates defines aggressive breast cancers with poor outcome

Beta1,6-n-acetylglucosaminyltransferase-V (GnT-V) catalyzes the addition of complex oligosaccharide side chains to glycoproteins, regulating the expression and function of several proteins involved in tumor metastasis. We analyzed the expression of five cell-surface glycoprotein substrates of GnT-V, matriptase, beta1-integrin, epidermal growth factor receptor, lamp-1, and N-cadherin, on a tissue microarray cohort of 670 breast carcinomas with 30-year follow-up. Phaseolus vulgaris leukocytic phytohemagglutinin (LPHA), a lectin specific for beta1,6-branched oligosaccharides, was used to assay GnT-V activity. Our results show a high degree of correlation of the LPHA staining with matriptase, lamp-1, and N-cadherin expressions, but not with epidermal growth factor receptor or beta1-integrin expressions. In addition, many of the GnT-V substrate proteins exhibited strong coassociations. Elevated levels of GnT-V substrates were correlated with various markers of tumor progression, including positive node status, large tumor size, estrogen receptor negativity, HER2/neu overexpression, and high nuclear grade. Furthermore, LPHA and matriptase showed significant association with disease-related survival. Unsupervised hierarchical clustering of the GnT-V substrate protein expression and LPHA revealed two distinct clusters: one with higher expression of all markers and poor patient outcome and one with lower expression and good outcome. These clusters showed independent prognostic value for disease-related survival when compared with traditional markers of tumor progression. Our results indicate that GnT-V substrate proteins represent a unique subset of coexpressed tumor markers associated with aggressive disease.

High expression ofN-acetylglucosaminyltransferase V in favorable neuroblastomas: Involvement of its effect on apoptosis

Neuroblastoma (NBL), derived from the sympathetic precursor cells, is one of the most common pediatric solid tumors. The expression of N-acetylglucosaminyltransferase V and IX (GnT-V and GnT-IX) mRNA in 126 primary NBLs were quantitatively analyzed and higher expression levels of GnT-V were found to be associated with favorable stages (1, 2 and 4s). Conversely, the downregulation of GnT-V expression by small interfering RNA resulted in a decrease in the susceptibility to cell apoptosis induced by retinoic acid in NBL cells accompanied by morphological change. These results suggest that GnT-V is associated with prognosis by modulating the sensitivity of NBLs to apoptosis.

Predictive Value of N -Acetylglucosaminyltransferase-V for Superficial Bladder Cancer Recurrence

PURPOSE

GnT-V is an enzyme that catalyzes beta1-6 branching of N-acetylglucosamine on asparagine (N)-linked oligosaccharides of cell proteins. GnT-V expression has been closely related to malignant potentials in colon cancer, brain cancer and hepatocellular carcinoma. We determined whether GnT-V expression is predictive of superficial bladder cancer recurrence.

MATERIALS AND METHODS

The cohort comprised 60 consecutive patients with first time superficial bladder cancer treated with transurethral resection. None of the patients received prophylactic intravesical therapy until recurrence. Paraffin embedded tumor specimens were immunohistochemically examined by the avidin-biotin peroxidase method using monoclonal antibody against GnT-V. Kaplan-Meier survival curves were generated to determine disease-free survival. Univariate and multivariate analyses were done to compare GnT-V expression to other clinical and pathological variables.

RESULTS

GnT-V expression correlated inversely with tumor grade and stage. The positive incidence of GnT-V in G1 to G3 tumors was 7 of 9 (78%), 21 of 43 (49%) and 3 of 8 (38%), respectively. GnT-V was positive in 26 of 44 cases of pTa (60%) and in 5 of 16 of pT1 (31%) disease. The 31 patients with positive GnT-V expression had significantly higher disease-free survival than the 29 with negative GnT-V expression (log rank test p = 0.0034). Multivariate analysis revealed that patient age, pT, grade and negative GnT-V expression were independent predictors of recurrence (p = 0.015, 0.001, 0.019 and 0.011, respectively).

CONCLUSIONS

Immunohistochemical detection of GnT-V is an independent predictor of superficial bladder cancer recurrence.

Analysis of Total N-Glycans in Cell Membrane Fractions of Cancer Cells Using a Combination of Serotonin Affinity Chromatography and Normal Phase Chromatography

Cell surface glycans and recognition molecules of these glycans play important roles in cellular recognition and trafficking, such as in the inflammation response by sialyl LewisX oligosaccharides. Malignant cells also utilize a similar mechanism during colonization and establishment of tumor tissues in the host. These considerations prompt us to develop a screening method for comprehensive analysis of N-glycans derived from membrane fractions of cancer cells. The method involves two step separations. Initially, N-glycans released from cell membrane fractions with N-glycoamidase F were labeled with 2-aminobenzoic acid and separated based on the number of sialic acid residues attached to the oligosaccharides using affinity chromatography on a serotonin-immobilized stationary phase. Each of the nonretarded fractions containing asialo- and high-mannose type oligosaccharides and mono-, di-, tri-, and tetra-sialooligosaccharide fractions which were desialylated with neuraminidase was analyzed by a combination of HPLC using an Amide-80 column as the stationary phase and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). We analyzed total N-glycan pools of membrane fractions obtained from some cancer cells, and found that U937 cells (Histocytic lymphoma cells) expressed a large amount of oligosaccharides having polylactosamine residues and MKN45 cells (Gastric adenocarcinoma cells) contained hyper-fucosylated oligosaccharides which contained multiple fucose residues. The method described here will be a powerful technique for glycomics studies in cell surface glycoproteins, and will enable one to search marker oligosaccharides characteristically observed in various diseases such as cancer, inflammation, and congenital disorder.

Expression of N-acetylglucosaminyltransferase V in the development of human esophageal cancers: immunohistochemical data from carcinomas and nearby noncancerous lesions

OBJECTIVE

N-Acetylglucosaminyltransferase V (GnT-V) is a key enzyme in the formation of branching asparagine-linked oligosaccharides and is linked to tumor invasion and metastasis in colon and breast cancers. In normal esophageal epithelium, beta1,6-branched asparagine-linked oligosaccharides synthesized by GnT-V are seen in the basal cell layers but not in the superficial cell layers, and its presence has been shown in invasive esophageal cancers. However, neither GnT-V expression nor its clinical significance has been previously examined in human normal, premalignant and malignant esophageal tissues.

METHODS

GnT-V expression was studied by immunohistochemistry using a specific monoclonal antibody in 121 surgically resected specimens of esophageal squamous cell carcinomas (SCCs) and adjacent tissues, and was analyzed statistically in relation to various characteristics.

RESULTS

GnT-V expression was observed in none (0%) of the 19 normal epithelial tissues, 1 (2%) of the 43 hyperplastic tissues, 30 (54%) of the 56 mildly dysplastic tissues, 27 (63%) of the 43 moderately dysplastic tissues, 21 (44%) of the 48 in situ SCCs and 29 (26%) of the 110 invasive SCCs (p<0.005). GnT-V expression was observed significantly more frequently in mildly and moderately dysplastic tissues when compared with normal epithelial and hyperplastic tissues (p<0.005), and its frequency was decreased in in situ and invasive SCCs (p<0.005). GnT-V expression was frequently observed in SCCs of small size and without distant metastasis or lymph node metastasis.

CONCLUSIONS

Increased expression of GnT-V is associated with the early event of esophageal tumorigenesis.

Beta1,6-branched oligosaccharides are increased in lymph node metastases and predict poor outcome in breast carcinoma

PURPOSE

This study was designed to provide a comprehensive assessment on the role of beta1,6-branched oligosaccharides in the metastasis and outcome of breast carcinoma. Generation of these structures on N-glycans is initiated by beta1,6-N-acetylglucosaminyltransferase V and used by both myeloid cells and cancer cells in systemic migration.

EXPERIMENTAL DESIGN

Tissue microarrays of >700 tumors (>400 patients; 30-year follow-up data) were stained through lectin histochemistry with leukocytic phytohemagglutinin (LPHA), a selective marker for beta1,6-branched oligosaccharides. Node-negative and node-positive primary tumors and patient-matched lymph node metastases were scored by blinded observers.

RESULTS

Metastases stained at significantly greater intensities than did the patient-matched primary tumors (P < 0.0001), demonstrating for the first time that the abundance of beta1,6-branched oligosaccharides was directly associated with breast carcinoma nodal metastasis. Multivariate analyses revealed that beta1,6-branched oligosaccharides in primary tumors were a predictor of poor outcome, most notably in node-negative tumors, where an LPHA staining score of 3+ gave a risk factor of 3.3, independent of tumor size, nuclear grade, or patient age (P = 0.007).

CONCLUSIONS

The data firmly establish a role for beta1,6-N-acetylglucosaminyltransferase V activity and beta1,6-branched oligosaccharides in breast carcinoma metastasis, and reemphasize the involvement, although poorly understood, of aberrant glycosylation in tumor progression.