Clinical usefulness of alterations in sialic acid, sialyl transferase and sialoproteins in breast cancer

Altered Glycosylation of Human Alpha-1-Acid Glycoprotein as a Biomarker for Malignant Melanoma

A high-resolution HILIC-MS/MS method was developed to analyze anthranilic acid derivatives of N-glycans released from human serum alpha-1-acid glycoprotein (AGP). The method was applied to samples obtained from 18 patients suffering from high-risk malignant melanoma as well as 19 healthy individuals. It enabled the identification of 102 glycan isomers separating isomers that differ only in sialic acid linkage (α-2,3, α-2,6) or in fucose positions (core, antenna). Comparative assessment of the samples revealed that upregulation of certain fucosylated glycans and downregulation of their nonfucosylated counterparts occurred in cancer patients. An increased ratio of isomers with more α-2,6-linked sialic acids was also observed. Linear discriminant analysis (LDA) combining 10 variables with the highest discriminatory power was employed to categorize the samples based on their glycosylation pattern. The performance of the method was tested by cross-validation, resulting in an overall classification success rate of 96.7%. The approach presented here is significantly superior to serological marker S100B protein in terms of sensitivity and negative predictive power in the population studied. Therefore, it may effectively support the diagnosis of malignant melanoma as a biomarker.

Comparative Evaluation of Salivary Sialic Acid Levels Among Beedi Rollers and Tobacco Users in Mangalore, South India

Introduction: According to World Health Organization, the global cancer burden is estimated to have risen to 18.1 million new cases and 9.6 million deaths in 2018. Tobacco use is a leading cause of cancer and of death from cancer. Beedis are the most popular smoking form of tobacco in India. Thirty-four percent of the tobacco produced in India is used for making beedis. The beedi sector is agroforestry-based and the second largest industry in India with approximately 4.4 million full-time beedi workers in India. Toxic constituents present in tobacco are released into the ambient air during the processing of beedis.

Methods: A descriptive cross-sectional study was conducted to assess and compare salivary sialic acid levels among beedi rollers, tobacco smokers, smokeless tobacco users and individuals with no tobacco exposure. The study sample comprised of 140 individuals who were 30 to 60 years old, who attended dental screening and treatment camps in rural and urban areas in Mangalore, conducted by the Department of Public Health Dentistry, Yenepoya Dental College and patients who visited the Department of Oral Medicine and Radiology of Yenepoya Dental College. Saliva was collected by passive drool method into a sterile container. Biochemical analysis of salivary sialic acid was done using the acidic ninhydrin method. Continuous variables are expressed in terms of mean and standard deviation. Categorical variables are expressed in terms of frequencies and percentages. To compare salivary sialic acid levels between the groups ANOVA was used. The Chi-square test was used to compare categorical variables between the groups.

Results: A total of 140 participants, 35 beedi rollers, 35 smokers, 35 smokeless tobacco users and 35 individuals with no tobacco exposure participated in the study. Among the 140 participants, 90 participants were males and 50 participants were females. There was a statistically significant difference in the mean salivary sialic acid level between the different groups (p<0.001) with smokeless tobacco users having the highest (10.60 mg/dL) mean salivary sialic acid level. It was found that the mean salivary sialic acid level reduced as the age progressed, even though there was no statistically significant difference. There was a statistically significant difference in the mean salivary sialic acid level between the different groups (p=0.010) with participants with 11 to 20 years of exposure to tobacco having the highest (8.67 mg/dL) mean salivary sialic acid level and participants with no tobacco exposure having least (3.06 mg/dL) mean salivary sialic acid level.

Conclusion: The salivary sialic acid level was more in beedi rollers than individuals with no tobacco exposure, even though the difference was not statistically significant. The results showed elevated levels of salivary sialic acid in smokeless tobacco users followed by tobacco smokers. This may be an indication that smokeless tobacco use has harmful effects similar to or more than tobacco smoking since salivary sialic acid levels in smokeless tobacco users were higher than those in smokers.

Usefulness of salivary sialic acid as a tumor marker in tobacco chewers with oral cancer

Aim

This study aims to assess the usefulness of salivary sialic acid (SA) as a tumor marker in the detection of oral squamous cell carcinoma (OSCC) among tobacco chewers.

Materials and Methods

After the approval of study protocol by the Institutional Ethics Committee and informed voluntary consent, salivary samples were collected from 96 participants in each group of tobacco chewers with OSCC, tobacco chewers without precancerous or cancerous lesion, and healthy controls. Salivary protein-bound SA (PBSA) and salivary-free SA (FSA) were measured by Yao et al.'s method of acid ninhydrin reaction, and the data were subjected to appropriate statistical analysis.

Results

The salivary PBSA and FSA levels in the Groups 1, 2, and 3 participants were 31.17 ± 7.6 mg/dL and 63.45 ± 9.8 mg/dL, 25.45 ± 16.61 mg/dL and 33.18 ± 11.38 mg/dL, and 22.73 ± 3.01 mg/dL and 21.62 ± 8.86 mg/dL, respectively. Salivary FSA levels were significantly increased among the tobacco chewers with OSCC patients (Group 1) and tobacco chewers with no premalignant lesions of the oral cavity (Group 2) compared to the healthy controls (Group 3) with P < 0.05 being statistically significant. Salivary FSA levels were significantly increased in Group 1 as compared with Group 2. The salivary PBSA was high among Group 1 as compared to the control Group 3; there was however no significant difference in the levels of salivary PBSA between Group 1 and Group 2. There was no significant difference in the PBSA levels between OSCC patients of Group 1 and the tobacco chewers without precancerous or cancerous lesion in the oral cavity of Group 2.

Conclusion

Salivary PBSA and FSA are significantly raised in both tobacco chewers with OSCC and in tobacco chewers with no precancerous or cancerous lesions in the oral cavity. SA should therefore be used cautiously while considering it as a marker for the early detection of oral cancer. Tobacco can be a crucial confounding factor when SA is used as a biomarker in OSCC since their levels are elevated to some extent even in tobacco chewers without any clinically obvious precancerous or cancerous lesions in the oral cavity.

Elevated Serum Sialic Acid Levels Predict Prostate Cancer As Well As Bone Metastases

Objective: To evaluate the value of serum sialic acid (SA) in diagnosis of benign prostatic hyperplasia (BPH), prostate cancer (PCa), and bone metastases in PCa patients. Materials and Methods: Data from 540 patients who were newly diagnosed with PCa or BPH between November 2014 and March 2018 were retrospectively collected and analyzed. Pretreatment SA levels were compared across various groups, then, associations between SA levels and clinic parameters of patients were analyzed as well. Univariate and multivariate logistic regression analyses were further used to identify independent associations. Results: The mean SA levels in patients with PCa were significantly higher than with BPH (p = 0.013). Furthermore, PCa patients with bone metastases showed elevated SA levels compared with PCa without bone metastases (p < 0.001). A multivariate logistic regression model showed that: SA level > 52.35 mg/dL was identified to be independently associated with the diagnosis of PCa (HR = 1.645, p = 0.036), and SA level > 59 mg/dL was identified to be independent association with the presence of bone metastases in PCa patients (HR = 6.421, p = 0.012). Conclusions: Elevated SA level is an independent predictor of prostate cancer as well as its bone metastases. Therefore, SA level may be a promising diagnostic and prognostic biomarker for prostate cancer and bone metastases.

Syringic acid may attenuate the oral mucosal carcinogenesis via improving cell surface glycoconjugation and modifying cytokeratin expression

Syringic acid (SRA) is an excellent anti-oxidant and anti-cancer property in various in vitro and in vivo studies. In the present study was modifying effect of SRA on 7,12-dimethylbenz(a)anthracene (DMBA) induced cell surface glycoconjugates (GCs) abnormalities in the plasma and buccal mucosa of golden Syrian hamster buccal pouch carcinogenesis (HBPCs). Topical application of DMBA three times a week for 10 weeks on the buccal pouches of the hamsters resulted in well developed squamous cell carcinoma. GCs status was assessed biochemically, histological and immunoexpression pattern of cytokeratin (CK) in the buccal mucosa of the DMBA treated hamsters. Elevated levels of GCs and CK expression were observed in DMBA alone treated hamsters. Oral pre-administration of SRA (50 mg/kg bw) positively modulates the GCs levels and CK expressions to near normal. The present findings suggested that SRA can protect cell surface GCs and CK expression during DMBA induced HBPCs.

Serum sialylation changes in cancer

Cancer is a major cause of death in both developing and developed countries. Early detection and efficient therapy can greatly enhance survival. Aberrant glycosylation has been recognized to be one of the hallmarks of cancer as glycans participate in many cancer-associated events. Cancer-associated glycosylation changes often involve sialic acids which play important roles in cell-cell interaction, recognition and immunological response. This review aims at giving a comprehensive overview of the literature on changes of sialylation in serum of cancer patients. Furthermore, the methods available to measure serum and plasma sialic acids as well as possible underlying biochemical mechanisms involved in the serum sialylation changes are surveyed. In general, total serum sialylation levels appear to be increased with various malignancies and show a potential for clinical applications, especially for disease monitoring and prognosis. In addition to overall sialic acid levels and the amount of sialic acid per total protein, glycoprofiling of specific cancer-associated glycoproteins, acute phase proteins and immunoglobulins in serum as well as the measurements of sialylation-related enzymes such as sialidases and sialyltransferases have been reported for early detection of cancer, assessing cancer progression and improving prognosis of cancer patients. Moreover, sialic-acid containing glycan antigens such as CA19-9, sialyl Lewis X and sialyl Tn on serum proteins have also displayed their value in cancer diagnosis and management whereby increased levels of these factors positively correlated with metastasis or poor prognosis.

Evaluation of Total and Lipid Bound Sialic Acid in Serum in Oral Leukoplakia

INTRODUCTION

Oral cancer has become the most common cause of cancer related mortality which may be preceded by oral potentially malignant disorders. Altered glycosylation of glycoconjugates, such as sialic acid are one of the most important molecular changes accompanied during malignant transformation in precancerous lesions like Oral Leukoplakia (OL), and correlating them histopathologically with grades of epithelial dysplasia which will serve clinical significance.

AIM

The aim of this study was to evaluate the significance of serum Total Sialic Acid (TSA) and serum Lipid Bound Sialic Acid (LSA) as a prognostic serum marker in Oral Leukoplakia.

MATERIALS AND METHODS

Blood samples were collected from 30 patients diagnosed with OL and 30 healthy controls. Serum sialic acid (total and lipid bound) levels were measured using spectrophotometer. Tissue samples were histopathologically typed and were graded for epithelial dysplasia. Data were analysed using Independent t-test and Kruskal Wallis method.

RESULTS

Serum levels of both total and lipid bound sialic acids were found to be increased in OL when compared to healthy controls. The mean TSA levels among those in the OL group (45.3±4.2) were significantly greater than healthy controls (29±2.2). On multiple comparison the highest mean TSA level was found in severe OL compared to moderate and mild OL (p<0.05). The mean levels of LSA were found to be statistically non-significant between the groups.

CONCLUSION

The present study showed that the serum levels of both TSA and LSA were found to be increased in OL when compared to apparently healthy controls. We also found that with increasing grades of epithelial dysplasia TSA levels were found to be gradually increasing which was significant for this study serving as an early indicator for the detection of malignant transformation in OL.

The effect of proanthocyanidin on formaldehyde-induced toxicity in rat testes

BACKGROUND/AIM

This study investigated the effect of proanthocyanidin (PA) against formaldehyde (FA)-induced lipid peroxidation damage and morphological changes in rat testes.

MATERIALS AND METHODS

Twenty-one Wistar albino rats were randomized into 3 groups: control, FA, and FA + PA groups. Plasma and tissue malondialdehyde (MDA) and total sialic acid (TSA) levels were measured. Testes tissues were observed by light and electron microscopy.

RESULTS

TSA (plasma and tissue) levels decreased and MDA (plasma) significantly increased (P < 0.05) in rats treated with FA compared to the controls. Tissue MDA levels were not significantly different. Several necrotic changes were observed in testes tissues by light and electron microscopy. Disordering in epithelia of seminiferous tubules, vacuolization between germinal epithelium cells, and separated basement membranes were observed by light microscope. Immunopositivity in Leydig cells decreased in the FA group (P < 0.05). In the FA + PA group there were more immune Leydig cells reacting immune-positively than in the FA group (P < 0.05). Ultrastructurally, FA also caused disorganization and loss of mitochondrial cristae, and dilatation in endoplasmic reticulum in testes.

CONCLUSION

The results suggest that PA has a protective effect on FA toxicity in testes.

Estimation of salivary sialic acid in oral premalignancy and oral squamous cell carcinoma

AIMS

Oral cancer is the most life-threatening disease of oral tissues. In societies where the incidence of oral cancer is high, clinically recognizable premalignant lesions are particularly common. Diagnosing oral cancers at an early stage is critical in improving the survival rate and reducing the morbidity associated with the disease. Alterations in the sialic acid levels in cancer patients have stimulated interest in this sugar residue as a possible tumor marker.

SETTINGS AND DESIGN

The purpose of this study was to estimate the salivary sialic acid levels in patients with oral premalignancy and squamous cell carcinoma and to correlate it with their grades to develop a cost-effective and noninvasive diagnostic parameter.

MATERIALS AND METHODS

Unstimulated whole saliva was collected from the groups under study and subjected to biochemical analysis for determination of sialic acid levels.

STATISTICAL ANALYSIS USED

The salivary sialic acid levels were correlated with the clinical stage and histological grade by one-way ANOVA (SPSS software version 15).

RESULTS

Salivary sialic acid was elevated in oral squamous cell carcinoma (OSCC) compared to oral premalignancy and control group. A statistically significant correlation was observed between the grades of squamous cell carcinoma, grades of dysplasia in premalignancy, and sialic acid level.

CONCLUSION AND CLINICAL SIGNIFICANCE

Evaluation of salivary sialic acid levels in premalignant and malignant lesions can serve as a screening tool. The mortality and morbidity of OSCC can be reduced if the lesions are diagnosed in early precancerous states using such noninvasive diagnostic methods for screening and monitoring of the population.

Investigation of the protective effects of proanthocyanidin and vitamin E against the toxic effect caused by formaldehyde on the liver tissue

We aimed to investigate of protective role of proanthocyanidin (PA) and vitamin E (vit E) against to toxic effect of formaldehyde (FA). Twenty-eight Wistar albino rats were divided into four groups: control group, rats treated with FA intraperitoneal (i.p.) (10 mg/kg), FA + vit E intragastric (i.g.) (30 mg/kg), and FA + PA i.g. (100 mg/kg). We assayed superoxide dismutase (SOD), glutathione peroxidase (Gpx), myeloperoxidase (MPO) activity and levels of malondialdehyde (MDA) and total sialic acid (TSA) in liver. Liver tissue was taken in order to morphological analysis and hepatocytes apoptosis using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay immunostaining. SOD decreased in FA and increased in FA + vit E and FA + PA (p < 0.05). Gpx didn't change in FA and increased in FA + PA (p < 0.05). No significant variation between the groups was found in MPO activity. MDA increased only in FA and decreased in FA + vit E and FA+PA (p < 0.05). TSA didn't alter in FA and FA + vit E but decreased in FA + PA (p < 0.05). Degeneration in hepatocytes and endothelial cells, cytoplasm losses, vacuolization, picnotic nuclei, and mononuclear cell infiltration were identified in FA. Degeneration in chromatin material, membrane damage in mitochondria and losses in mitochondrial cristae in hepatocytes were observed in FA. We found that partially recovery in liver as a result of FA + vit E and FA + PA. We have concluded that long term use should be investigated for complete explanation of PA's protective effects on FA toxicity.

Enhanced expression of polysialic acid correlates with malignant phenotype in breast cancer cell lines and clinical tissue samples

Polysialic acid (PSA) is highly expressed during embryonic development, but barely expressed during postnatal development, and may be 're-expressed' in cancer tissues. In this study, motility and migration assays were performed to compare the changes in cell behavior between non-malignant and maligant cells. Next, the expression levels of PSA were evaluated in 4 human and mouse normal breast or breast cancer (BC) cell lines using 1,2-diamino-4,5-methylenedioxybenzene-labeling HPLC technology, as well as in human clinical BC tissue samples. PSA expression was significantly higher in malignant cells (where it appeared to facilitate cell migration and motility) than in non-malignant cells. Enhanced PSA expression levels were also observed during epithelial-mesenchymal transition (EMT), a leading cause of cancer cell metastasis, which was induced in the NMuMG and MCF10A cells by treatment with transforming growth factor-β1 (TGF-β1). An increased PSA expression also correlated with the disease stage in the patients with BC (P<0.0001). Using RT-qPCR, we found that polysialyltransferase ST8SiaIV (PST) and polysialyltransferase ST8SiaII (STX), which are responsible for PSA synthesis, were differently expressed in the tested BC samples. However, PST, but not STX, was re-expressed in 14 out of 20 clinical BC samples. The findings of the present study indicate that the pathophysiology of BC involves the aberrant regulation of PSA expression and PST gene expression.

A study of lipid- and protein- bound sialic acids for the diagnosis of bladder cancer and their relationships with the severity of malignancy

BACKGROUND

The gold standard for detection of bladder cancer is cystoscopy, which is an invasive and complicated procedure. Our study was conducted to find a tumor marker with high specificity, sensitivity, and accuracy for the diagnosis of bladder cancer.

METHODS

Serum samples were collected from 58 bladder cancer patients and 60 healthy control subjects. Levels of lipid-bound sialic acid (LBSA), and protein-bound sialic acid (PBSA) were measured spectrophotometrically by Aminoff's method.

RESULTS

Mean levels of both markers were found to be significantly higher in the patients than the healthy controls. Positive correlations were observed between serum levels of lipid- (r=0.283, p<0.05) and protein- bound (r=0.56, p<0.05) sialic acids and the grade of malignancy. To differentiate patients with bladder tumors from healthy controls, cut-offpoints were determined for each of the two parameters based on Receiver Operating Characteristic (ROC) curve analysis (LBSA=21.25 mg/dL, PBSA=6.15 mg/dL). The data showed good sensitivities (LBSA=89%, PBSA=79%), specificities (LBSA=70%, PBSA=70%) and accuracies (LBSA=83%, PBSA=81%) for both markers.

CONCLUSION

Measuring serum LBSA and PBSA by this simple, reproducible, noninvasive, and inexpensive method can accurately discriminate cancer patients from healthy individuals.

Quantitative evaluation and correlation of serum glycoconjugates: Protein bound hexoses, sialic acid and fucose in leukoplakia, oral sub mucous fibrosis and oral cancer

BACKGROUND

Cancer is one of the most common causes of mortality and morbidity today, with more than 10 million new cases and more than 6 million deaths each year worldwide. Globally Oral Cancer is the sixth most common cause of cancer related death. India accounts for 86% of the world's oral cancer cases. Often it proceeds by pre cancerous conditions and lesions. In search for biological markers with diagnostic value, we investigated serum glycoconjugates like protein bound hexoses, fucose and sialic acid in these diseases.

MATERIALS AND METHODS

For this Study 27 newly diagnosed Oral leukoplakia, 27 OSMF and 26 Oral Cancer patients, 40 healthy controls who are non tobacco users and 40 healthy controls who are tobacco users were selected. In all these groups we estimated serum glycoconjugates.

RESULTS

We observed no difference in serum glycoconjugates levels between tobacco and non tobacco controls (P > 0.05), but very high levels in oral cancer, Leukoplakia and oral sub mucous fibrosis (OSMF) patients (P < 0.001) when compared to control groups. Fucose levels were significant (P < 0.05) of all the glycoconjugates between OSMF and Leukoplakia.

CONCLUSION

The serum glycoconjugates whose levels were very high in OSMF, Leukoplakia and Oral Cancer, do have a significant diagnostic and prognostic value in these diseases.

Glycoprotein electrophoretic patterns have potential to monitor changes associated with neoplastic transformation in oral cancer

Alterations in glycoproteins, important cell surface constituents, have long been associated with various malignancies. The present investigation therefore explored the clinical significance of a glycoproteomics approach in patients with oral precancerous conditions (OPC) and patients with oral cancer. The study included 80 oral cancer patients, 50 patients with OPC, and 84 controls. Native polyacrylamide gel electrophoresis followed by Schiff’s staining was carried out to study the alterations in glycoproteins. The results showed significant elevation (p<0.0001) of 192 kDa, 170 kDa, 116 kDa and 44 kDa glycoproteins in oral cancer patients and patients with OPC compared with controls. The odds ratio indicated a significantly higher risk for oral cancer among users and especially chewers of tobacco. The levels of all the glycoprotein bands (192 kDa, 170 kDa, 116 kDa and 44 kDa) were higher in patients with a habit of tobacco use (WHT) than in patients with no habit of tobacco (NHT) and were also higher in WHT controls than in NHT controls. Moreover, a 230 kDa glycoprotein consistently appeared only in individuals with tobacco habits and an increasing trend was observed from WHT controls to patients with OPC to WHT oral cancer patients. In conclusion, the results indicated the potential utility of glycoprotein alterations in monitoring sequential changes occurring due to tobacco consumption during neoplastic transformation.

Comparing Self-Assembling and Covalent Fluorescent Boronolectins for the Detection of Free Sialic Acid

A self-assembling fluorescence sensor with boronic acid functionalities was tested for binding selectivity to the monosaccharide, sialic acid. Working from a previously reported system, a self-assembling system could form an imine in situ that enables a conjugated fluorophore to display a measurable change in fluorescence in the presence of monosaccharide. However, further examination showed that free sugars give a similar fluorescence response to just the m-aminophenylboronic acid moiety on its own. Still, such a self-assembly method may be applicable to cell surface saccharide sensing as aldehydes and ketones are noticeably absent on most cells’ exteriors. The original covalent receptor appears best suited for the detection of free sialic acid.

Effect of vitamin E on protein bound carbhohydrate complexes in radiation treated oral squamous cell carcinoma patients

Serum glycoproteins were evaluated in oral squamous cell carcinoma patients treated with radiotherapy and also the effect of vitamin E was studied. Cell surface glycoconjugates are important parameters in the detection of malignancy. Thus, the objective of the present study is to evaluate the efficacy of vitamin E on glycoproteins in oral cavity cancer patients treated with radiotherapy. The study includes 26 age and sex matched normal healthy individuals and 26 patients with squamous cell carcinoma of oral cavity. These patients were divided into two groups, one for radiotherapy alone (at a dosage of 6000 cGy in five fractions per week for a period of six weeks) and the other for radiotherapy plus vitamin E supplementation (at a dosage of 400 IU / day of vitamin E) for the entire period of radiotherapy. Levels of hexose, hexosamine, fucose and sialic acid were increased in oral squamous cell carcinoma patients and a significant decrease was observed in radiation treated patients when compared to control. The levels of glycoconjugates were significantly decreased in radiation treated patients supplemented with vitamin E. This measurement may be useful in assessing disease progression and identifying patients resistant to therapy and a possible role of vitamin E on reduction in glycoconjugate levels of radiation treated oral squamous cell carcinoma patients.

Serum total sialic acid in differential diagnostics of jaundice caused by malignant and nonmalignant diseases: a ROC curve analysis

The purpose of this study was to evaluate the usefulness of serum total sialic acid (SA) for discrimination of malignant and nonmalignant jaundice. Serum SA concentration and its ratio with total protein (SA/TP) were determined in 55 patients with jaundice: 25 malignant and 30 nonmalignant. SA was estimated by enzymatic method. Serum total SA and the ratio SA/TP were significantly higher in malignant than in nonmalignant jaundice. Diagnostic sensitivity of SA and the ratio of SA/TP in both types of jaundice reached the value of 95.8%. The specificity, positive and negative predictive values, and efficiency of SA and SA/TP were higher in malignant than in nonmalignant jaundice. Areas under ROC curves for SA and the ratio of SA/TP in malignant jaundice were higher than in nonmalignant, but there were not statistically significant differences. SA levels and the ratio of SA/TP do not have the ability to discriminate between these types of jaundice.