Gamma-synuclein is a novel prognostic marker that promotes tumor cell migration in biliary tract carcinoma.

Gamma-synuclein (SNCG) promotes invasive behavior and is reportedly a prognostic factor in a range of cancers. However, its role in biliary tract carcinoma (BTC) remains unknown. Consequently, we investigated the clinicopathological significance and function of SNCG in BTC. Using resected BTC specimens from 147 patients with adenocarcinoma (extrahepatic cholangiocarcinoma [ECC, n = 96]; intrahepatic cholangiocarcinoma [ICC, n = 51]), we immunohistochemically evaluated SNCG expression and investigated its correlation with clinicopathological factors and outcomes. Furthermore, cell lines with high SNCG expression were selected from 16 BTC cell lines and these underwent cell proliferation and migration assays by siRNAs. In the results, SNCG expression was present in 22 of 96 (22.9%) ECC patients and in 10 of 51 (19.6%) ICC patients. SNCG expression was significantly correlated with poorly differentiated tumor in both ECC and ICC (p = 0.01 and 0.03, respectively) and with perineural invasion and lymph node metastases in ECC (p = 0.04 and 0.003, respectively). Multivariate analyses revealed that SNCG expression was an independent poor prognostic factor in both OS and RFS in both ECC and ICC. In vitro analyses showed high SNCG expression in three BTC cell lines (NCC-BD1, NCC-BD3, and NCC-CC6-1). Functional analysis revealed that SNCG silencing could suppress cell migration in NCC-BD1 and NCC-CC6-1 and downregulate cell proliferation in NCC-CC6-1 significantly. In conclusion, SNCG may promote tumor cell activity and is potentially a novel prognostic marker in BTC.

Gamma-Synuclein Levels Are Elevated in Peritoneal Fluid of Patients with Endometriosis.

BACKGROUND The role of gamma-synuclein (SNCG) has been widely examined in malignant conditions due to its possible role in disease progression, but very little information is available on its theoretical function on endometriosis formation. MATERIAL AND METHODS Between January 2016 and December 2016, we collected peritoneal fluid and plasma samples from 45 consecutive female patients, of which 15 were without endometriosis, 15 had minimal to mild endometriosis, and 15 had moderate to severe endometriosis. The statistical power was 0.98. We evaluated SNCG levels in the peritoneal fluid and plasma of patients diagnosed with endometriosis, and we compared them with the levels obtained from disease-free control subjects by using enzyme-linked immunosorbent assay. RESULTS SNCG levels were statistically significantly (1.2-fold) higher in the peritoneal fluid of patients with endometriosis compared to controls (p=0.04). We did not find a significant difference between SNCG levels in the plasma of our endometriosis patients and the control group (p=0.086). However, despite previous data showing very limited expression of SNCG in healthy tissues, we found SNCG in the peritoneal fluid of all of the patients in our healthy control group. CONCLUSIONS Levels of SNCG were statistically significantly higher in the peritoneal fluid of patients with endometriosis compared to disease-free controls, which may indicate its possible role the formation and progression of the disease. Moreover, its biological function should be further investigated due to the conflicting results concerning its expression in healthy tissues.

Evaluation of synuclein-γ levels by novel monoclonal antibody in saliva and cancer tissues from oral squamous cell carcinoma patients.

The clinical value of synuclein-γ (SNCG) in oral squamous cell carcinoma (OSCC) was evaluated by detecting the expression of SNCG in saliva and tissues and its correlation with clinicopathological parameters (age, gender, ethnicity, degree of differentiation, clinical stage, and lymph node metastasis). Salivary samples were collected from 79 patients with OSCC, 31 patients with oral premalignant lesions (OPMLs), such as oral lichen planus, oral leukoplakia, and erythema, and 80 controls, and levels of SNCG in salivary samples were determined by enzyme-linked immunosorbent assay (ELISA). Tissue expression in formalin-fixed tissue biopsies of 94 cases of OSCC and 30 adjacent normal tissues was analyzed by immunohistochemistry (IHC) using an antibody against SNCG. The results showed that the salivary levels of SNCG in patients with OSCC and OPMLs were significantly higher than those detected in the control group (p<0.001). The immunohistochemical results showed that SNCG was highly expressed in tumor cells of OSCC patients, with low expression in the adjacent normal epithelium (p<0.001, OR=6.074). Salivary SNCG level correlated with differentiation (p=0.022). Besides, the expression of SNCG in OSCC tissues was also significantly associated with differentiation (p<0.001).

Overexpression of synuclein-γ predicts lack of benefit from radiotherapy for breast cancer patients.

BACKGROUND: Although radiotherapy following mastectomy was demonstrated to reduce the recurring risk and improve the prognosis of patients with breast cancer, it is also notorious for comprehensive side effects, hence only a selected group of patients can benefit. Therefore, the screening of molecular markers capable of predicting the efficacy of radiotherapy is essential. METHODS: We have established a cohort of 454 breast cancer cases and selected 238 patients with indications for postoperative radiotherapy. Synuclein-γ (SNCG) protein levels were assessed by immunohistochemistry, and SNCG status was retrospectively correlated with clinical features and survival in patients treated or not treated with radiotherapy. Gene Set Enrichment Analysis (GSEA) and survival analysis for online datasets were also performed for further validation. RESULTS: Among patients that received radiotherapy (82/238), those demonstrating positive SNCG expression had a 55.0 month shorter median overall survival (OS) in comparison to those demonstrating negative SNCG expression (78.4 vs. 133.4 months, log rank χ (2) = 16.13; p < 0.001). Among the patients that received no radiotherapy (156/238), SNCG status was not correlated with OS (log rank χ (2) = 2.40; p = 0.121). A COX proportional hazard analysis confirmed SNCG as an independent predictor of OS, only for patients who have received radiotherapy. Similar results were also obtained for distant metastasis-free survival (DMFS). A GSEA analysis indicated that SNCG was strongly associated with genes related to a radiation stress response. A survival analysis was performed with online databases consisting of breast cancer, lung cancer, and glioblastoma and further confirmed SNCG's significance in predicting the survival of patients that have received radiotherapy. CONCLUSION: A positive SNCG may serve as a potential marker to identify breast cancer patients who are less likely to benefit from radiotherapy and may also be extended to other types of cancer. However, the role of SNCG in radiotherapy response still needs to be further validated in randomized controlled trials prior to being exploited in clinical practice.

Predictive and prognostic values of BubR1 and synuclein-gamma expression in breast cancer.

The aim of this study is to determine the expression level of spindle assembly checkpoint (SAC) proteins-BubR1 and synuclein-gamma (SNCG) in human breast cancer tissues and to test whether there is a relationship between their expression levels and clinicopathologic parameters including respons to taxanes, tumor grade, estrogen receptor (ER) pozitivity, HER2 status, and overall survival (OS). We analyzed retrospectively paraffin-embedded tissue sections from 55 breast cancer patients whose clinical outcomes had been tracked after taxane treatment in neoadjuvan and metastatic setting. The expression status of BubR1 and SNCG was defined by immunohistochemistry (IHC) using the anti-BubR1 and anti-SNCG antibody. The BubR1 and SNCG was overexpressed in 38% and 62% of the study group, respectively. There was borderline significant correlation between low BubR1 expression and increased taxane sensitivity (P=0.05). In contrast, high SNCG expression was significantly associated with decreased taxane sensitivity (P=0.01). There was no association between the clinicopathologic parameters including histologic grade, ER positivity and HER2 status and the level of these proteins. However, triple negative tumors showed significantly more high BubR1 expression than those other molecular subtypes (P=0.04). Kaplan-Meier survival analysis failed to show a significant correlation between expression levels of BubR1 and SNCG and overall survival although patients with low levels of both proteins had a marginally longer survival time compared to those with high levels. In summary, our data suggest that both BubR1 and SNCG may be promising predictive marker rather than prognostic marker in patients with breast cancer.

Expression of SNCG, MAP2, SDF-1 and CXCR4 in gastric adenocarcinoma and their clinical significance.

OBJECTIVES: The purpose of the study was to detect the expression of SNCG, MAP2, SDF-1 and CXCR4 in gastric adenocarcinoma, and to evaluate their roles in the carcinogenesis of gastric adenocarcinoma, development, invasion and metastasis as well as their clinical significance. METHODS: The expression of SNCG, MAP2, SDF-1 and CXCR4 was detected by SP immunohistochemical method in 225 cases of gastric adenocarcinoma and 105 cases of nonneoplastic adjacent gastric tissue. The expression of SNCG, MAP2, SDF-1 and CXCR4 mRNA was also detected by RT-PCR method in 50 cases of gastric adenocarcinoma and 30 cases of nonneoplastic adjacent gastric tissue. RESULTS: The expression of SNCG, MAP2, SDF-1 and CXCR4 in the gastric adenocarcinoma was remarkably higher than those in the nonneoplastic adjacent gastric tissue (P < 0.01); The positive expression of SNCG and MAP2 was correlated with the depth of tumor invasion and the metastasis of lymph nodes (P < 0.05), and that of SDF-1 and CXCR4 was correlated with the metastasis of lymph nodes (P < 0.05). CONCLUSIONS: SNCG, MAP2, SDF-1 and CXCR4 may play an important role in the carcinogenesis, progression, invasion and metastasis of gastric adenocarcinoma. However, it still needs more exploration whether they can serve as promising therapeutic targets of gastric adenocarcinoma.

New α- and γ-synuclein immunopathological lesions in human brain.

INTRODUCTION: Several neurodegenerative diseases are classified as proteopathies as they are associated with the aggregation of misfolded proteins. Synucleinopathies are a group of neurodegenerative disorders associated with abnormal deposition of synucleins. α-Synucleinopathies include Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Recently accumulation of another member of the synuclein family- γ-synuclein in neurodegenerative diseases compelled the introduction of the term γ-synucleinopathy. The formation of aggregates and deposits of γ-synuclein is facilitated after its oxidation at methionine 38 (Met38). RESULTS: Several types of intracytoplasmic inclusions containing post-translationally modified α- and γ-synucleins are detected. Oxidized Met38-γ-synuclein forms aberrant inclusions in amygdala and substantia nigra. Double staining revealed colocalization of oxidized-γ-synuclein with α-synuclein in the cytoplasm of neurons. Another type of synuclein positive inclusions in the amygdala of dementia with Lewy bodies patients has the appearance of Lewy bodies. These inclusions are immunoreactive when analyzed with antibodies to α-synuclein phosphorylated on serine 129, as well as with antibodies to oxidized-γ-synuclein. Some of these Lewy bodies have doughnut-like shape with round or elongated shape. The separate immunofluorescent images obtained with individual antibodies specific to oxidized-γ-synuclein and phospho-α-synuclein clearly shows the colocalization of these synuclein isoforms in substantia nigra inclusions. Phospho-α-synuclein is present almost exclusively at the periphery of these structures, whereas oxidized-γ-syn immunoreactivity is also located in the internal parts forming dot-like pattern of staining. CONCLUSIONS: These results reveal new γ-synuclein positive lesions in human brain. Oxidized-γ-synuclein is colocalized with phospho-α-synuclein in doughnut-like inclusions. Several types of astrocytes with different morphology are immunopositive for oxidized-γ-synuclein.

The correlation between expression of synuclein-gamma, glucose transporter-1, and survival outcomes in endometrioid endometrial carcinoma.

PURPOSE: To evaluate the correlation between immunohistochemical expression of synuclein-gamma, glucose transporter-1, and survival outcomes in endometrioid endometrial carcinoma. MATERIALS AND METHODS: A tissue microarray was constructed using formalinfixed, paraffin-embedded tissue that included 23 early and 18 advanced cases. The intensity and area of the immunohistochemical reactions were evaluated using the semi-quantitative scoring system. RESULTS: Synuclein-y expression was higher in the advanced stage, although it was not statistically significant (p = 0.51). Glucose transporter-1 was overexpressed in the advanced stage (p = 0.01). Synuclein-gamma (score = 0 vs > 0) and glucose transporter-1 (score < or = 7 vs > 7) did not show any differences in overall survival (p = 0.54, p = 0.48) and disease-free survival (p = 0.61, p = 0.14). CONCLUSION: In this study the expression of synuclein-y and glucose transporter-1 were not considered to be a prognostic factor and were not related with survival outcomes in endometrioid endometrial carcinoma.

Up-regulation of gamma-synuclein contributes to cancer cell survival under endoplasmic reticulum stress.

Previous studies have demonstrated that gamma-synuclein is overexpressed in a variety of human malignancies. Overexpression of gamma-synuclein in human breast cancer cells leads to an increase in cell motility, resistance to chemotherapeutic drugs, and mitotic checkpoint dysfunction. We report in this study that gamma-synuclein is up-regulated by endoplasmic reticulum stress. The up-regulation of gamma-synuclein expression by endoplasmic reticulum stress is mediated, at least in part, by activation transcription factor (ATF) 4. Knockdown of gamma-synuclein sensitized human breast cancer cells to endoplasmic reticulum stress-induced apoptosis. Induction of apoptosis by endoplasmic reticulum stress when gamma-synuclein was inhibited was dependent on JNK or caspase activation, with caspase-3 and caspase-7 being involved. Treatment with the JNK or caspase-3 and caspase-7 inhibitor partially blocked endoplasmic reticulum stress-induced apoptosis in breast cancer cells transfected with or without the siRNA against gamma-synuclein. Taken together, these data suggest that gamma-synuclein may promote cancer progression by suppressing endoplasmic reticulum stress-induced apoptosis.

Applications of novel monoclonal antibodies specific for synuclein-gamma in evaluating its levels in sera and cancer tissues from colorectal cancer patients.

Overexpressions of synuclein-gamma (SNCG) in different cancers display stage-specific patterns. At present, appropriate anti-SNCG monoclonal antibodies (mAbs) with high specificity and affinity are unavailable for different immunoassays in clinical applications. In this study, we generated 10 mAbs against endogenous SNCG and evaluated SNCG levels in several colorectal cancer cell lines, serum samples and tumor tissues from colorectal cancer (CRC) patients. Elevated SNCG levels in cancer cell lines evaluated by a novel sandwich ELISA were consistent with data obtained from Western blot. Secreted SNCG protein levels in sera from CRC patients could be detected by the sandwich ELISA and were further confirmed by Western blot analysis following SNCG enrichment. Immunohistochemical results showed that SNCG was highly expressed in tumor cells of CRC patients, but was undetectable in the adjacent normal epithelium. Taken together, these novel anti-SNCG mAbs specifically recognized endogenous SNCG and were suitable for measuring SNCG levels in cell lysates, human serum samples, and tumor tissues. Elevated serum SNCG and overexpressed SNCG in tumor tissue from CRC patients suggest SNCG is a potential biomarker for CRC.

Gamma-synuclein is an adipocyte-neuron gene coordinately expressed with leptin and increased in human obesity.

Recently, we characterized tumor suppressor candidate 5 (Tusc5) as an adipocyte-neuron PPARgamma target gene. Our objective herein was to identify additional genes that display distinctly high expression in fat and neurons, because such a pattern could signal previously uncharacterized functional pathways shared in these disparate tissues. gamma-Synuclein, a marker of peripheral and select central nervous system neurons, was strongly expressed in white adipose tissue (WAT) and peripheral nervous system ganglia using bioinformatics and quantitative PCR approaches. Gamma-synuclein expression was determined during adipogenesis and in subcutaneous (SC) and visceral adipose tissue (VAT) from obese and nonobese humans. Gamma-synuclein mRNA increased from trace levels in preadipocytes to high levels in mature 3T3-L1 adipocytes and decreased approximately 50% following treatment with the PPARgamma agonist GW1929 (P < 0.01). Because gamma-synuclein limits growth arrest and is implicated in cancer progression in nonadipocytes, we suspected that expression would be increased in situations where WAT plasticity/adipocyte turnover are engaged. Consistent with this postulate, human WAT gamma-synuclein mRNA levels consistently increased in obesity and were higher in SC than in VAT; i.e. they increased approximately 1.7-fold in obese Pima Indian adipocytes (P = 0.003) and approximately 2-fold in SC and VAT of other obese cohorts relative to nonobese subjects. Expression correlated with leptin transcript levels in human SC and VAT (r = 0.887; P < 0.0001; n = 44). Gamma-synuclein protein was observed in rodent and human WAT but not in negative control liver. These results are consistent with the hypothesis that gamma-synuclein plays an important role in adipocyte physiology.