Targeting synuclein-gamma to counteract drug resistance in cancer

Aberrant methylation modifications reflect specific drug responses in small cell lung cancer

In the study, Methylated DNA immunoprecipitation sequencing, RNA sequencing, and whole-exome sequencing were employed to clinical small cell lung cancer (SCLC) patients. Then, we verified the therapeutic predictive effects of differentially methylated genes (DMGs) in 62 SCLC cell lines. Of 4552 DMGs between chemo-sensitive and chemo-insensitive group, coding genes constituted the largest percentage (85.08%), followed by lncRNAs (10.52%) and miRNAs (3.56%). Both two groups demonstrated two methylation peaks near transcription start site and transcription end site. Two lncRNA-miRNA-mRNA networks suggested the extensive genome connection between chemotherapy efficacy-related non-coding RNAs (ncRNAs) and mRNAs. Combing miRNAs and lncRNAs could effectively predict chemotherapy response in SCLC. In addition, we also verified the predictive values of mutated genes in SCLC cell lines. This study was the first to evaluate multiple drugs efficacy-related ncRNAs and mRNAs which were modified by methylation in SCLC. DMGs identified in our research might serve as promising therapeutic targets to reverse drugs-insensitivity by complex lncRNA-miRNA-mRNA mechanisms in SCLC.

Evolvability of Amyloidogenic Proteins in Human Brain

Currently, the physiological roles of amyloidogenic proteins (APs) in human brain, such as amyloid-β and α-synuclein, are elusive. Given that many APs arose by gene duplication and have been resistant against the pressures of natural selection, APs may be associated with some functions that are advantageous for survival of offspring. Nonetheless, evolvability is the sole physiological quality of APs that has been characterized in microorganisms such as yeast. Since yeast and human brain may share similar strategies in coping with diverse range of critical environmental stresses, the objective of this paper was to discuss the potential role of evolvability of APs in aging-associated neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. Given the heterogeneity of APs in terms of structure and cytotoxicity, it is argued that APs might be involved in preconditioning against diverse stresses in human brain. It is further speculated that these stress-related APs, most likely protofibrillar forms, might be transmitted to offspring via the germline, conferring preconditioning against forthcoming stresses. Thus, APs might represent a vehicle for the inheritance of the acquired characteristics against environmental stresses. Curiously, such a characteristic of APs is reminiscent of Charles Darwin's 'gemmules', imagined molecules of heritability described in his pangenesis theory. We propose that evolvability might be a physiological function of APs during the reproductive stage and neurodegenerative diseases could be a by-product effect manifested later in aging. Collectively, our evolvability hypothesis may play a complementary role in the pathophysiology of APs with the conventional amyloid cascade hypothesis.

Combining affinity propagation clustering and mutual information network to investigate key genes in fibroid

The aim of the present study was to investigate key genes in fibroids based on the multiple affinity propogation-Krzanowski and Lai (mAP-KL) method, which included the maxT multiple hypothesis, Krzanowski and Lai (KL) cluster quality index, affinity propagation (AP) clustering algorithm and mutual information network (MIN) constructed by the context likelihood of relatedness (CLR) algorithm. In order to achieve this goal, mAP-KL was initially implemented to investigate exemplars in fibroid, and the maxT function was employed to rank the genes of training and test sets, and the top 200 genes were obtained for further study. In addition, the KL cluster index was applied to determine the quantity of clusters and the AP clustering algorithm was conducted to identify the clusters and their exemplars. Subsequently, the support vector machine (SVM) model was selected to evaluate the classification performance of mAP-KL. Finally, topological properties (degree, closeness, betweenness and transitivity) of exemplars in MIN constructed according to the CLR algorithm were assessed to investigate key genes in fibroid. The SVM model validated that the classification between normal controls and fibroid patients by mAP-KL had a good performance. A total of 9 clusters and exemplars were identified based on mAP-KL, which were comprised of CALCOCO2, COL4A2, COPS8, SNCG, PA2G4, C17orf70, MARK3, BTNL3 and TBC1D13. By accessing the topological analysis for exemplars in MIN, SNCG and COL4A2 were identified as the two most significant genes of four types of methods, and they were denoted as key genes in the progress of fibroid. In conclusion, two key genes (SNCG and COL4A2) and 9 exemplars were successfully investigated, and these may be potential biomarkers for the detection and treatment of fibroid.

Synuclein-γ (SNCG) expression in ovarian cancer is associated with high-risk clinicopathologic disease

Background

Synuclein gamma (SNCG) expression is associated with advanced disease and chemoresistance in multiple solid tumors. Our goal was to determine if SNCG protein expression in ovarian cancer was correlated with clinicopathologic variables and patient outcomes.

Methods

Tissue microarrays from primary tumors of 357 ovarian, fallopian tube, and primary peritoneal cancer patients, who underwent primary surgery at Roswell Park Cancer Institute between 1995 and 2007, were immunohistochemically stained for SNCG. A pathologist blinded to patient data scored tumors as positive if ≥10 % of the sample stained for SNCG. Medical records were reviewed for clinicopathologic and demographic variables. Between the positive and negative groups, Wilcoxon rank-sum test was used to compare the median ages and Fisher’s exact test was used to compare groups in categorical variables. Cox proportional hazard models examined associations between SNCG and overall and progression-free survival.

Results

The median follow-up was 36 months, median overall survival was 39 months, and median progression-free survival was 18 months. SNCG presence was associated with clinical variables of serous histology, grade 3 disease, suboptimal debulking, ascites at surgery, FIGO stage III-IV cancer, or initial CA-125 level >485. There was no significant difference in overall survival (HR 1.06 95 % CI 0.81–1.39 P 0.69) or progression-free survival (HR 1.16 95 % CI 0.89–1.50 P 0.28) for patients with or without SNCG expression.

Conclusions

SNCG expression in ovarian cancer is frequent in patients with high-risk features, but it does not correlate with chemotherapy response, overall survival, or progression-free survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s13048-016-0281-4) contains supplementary material, which is available to authorized users.

Gamma-synuclein binds to AKT and promotes cancer cell survival and proliferation

Hyperactivation of AKT plays a critical role in the survival and proliferation of cancer cells. However, the molecular mechanisms underlying AKT activation remain elusive. Here, we tested the effect of γ-synuclein, a member of the synuclein family of proteins, on the activation of AKT. We show that the expression level of γ-synuclein is increased in non-small cell lung cancer (NSCLC) tissues. γ-Synuclein binds to the protein kinase domain of AKT and promotes its phosphorylation. Overexpression of γ-synuclein in H157 cells enhances cell proliferation and protects the cells from staurosporine-induced cytotoxicity. Knockdown of γ-synuclein attenuates AKT activation and cell proliferation induced by epidermal growth factor. The effect of γ-synuclein is abolished when AKT is depleted. Thus, γ-synuclein promotes cell survival and proliferation via activating AKT and may play a causal role in the pathogenesis of NSCLC.

Current Status of Long Non-Coding RNAs in Human Breast Cancer

Breast cancer represents a major health burden in Europe and North America, as recently published data report breast cancer as the second leading cause of cancer related death in women worldwide. Breast cancer is regarded as a highly heterogeneous disease in terms of clinical course and biological behavior and can be divided into several molecular subtypes, with different prognosis and treatment responses. The discovery of numerous non-coding RNAs has dramatically changed our understanding of cell biology, especially the pathophysiology of cancer. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts >200 nucleotides in length. Several studies have demonstrated their role as key regulators of gene expression, cell biology and carcinogenesis. Deregulated expression levels of lncRNAs have been observed in various types of cancers including breast cancer. lncRNAs are involved in cancer initiation, progression, and metastases. In this review, we summarize the recent literature to highlight the current status of this class of long non-coding lncRNAs in breast cancer.

Intracellular Dynamics of Synucleins: "Here, There and Everywhere"

Synucleins are small, soluble proteins expressed primarily in neural tissue and in certain tumors. The synuclein family consists of three members: α-, β-, and γ-synucleins present only in vertebrates. Members of the synuclein family have high sequence identity, especially in the N-terminal regions. The synuclein gene family came into the spotlight, when one of its members, α-synuclein, was found to be associated with Parkinson's disease and other neurodegenerative disorders, whereas γ-synuclein was linked to several forms of cancer. There are a lot of controversy and exciting debates concerning members of the synuclein family, including their normal functions, toxicity, role in pathology, transmission between cells and intracellular localization. Important findings which remain undisputable for many years are synuclein localization in synapses and their role in the regulation of synaptic vesicle trafficking, whereas their presence and function in mitochondria and nucleus is a debated topic. In this review, we present the data on the localization of synucleins in two intracellular organelles: the nucleus and mitochondria.

Unregulated long non-coding RNA-AK058003 promotes the proliferation, invasion and metastasis of breast cancer by regulating the expression levels of the γ-synuclein gene

The aim of the present study was to investigate the function of long chain non-coding RNA (lncRNA) in breast cancer cells. Quantitative polymerase chain reaction was used to measure mRNA expression levels in breast cancer tissues, adjacent tissues and in MCF-7 breast cancer cells. Western blot analysis was used to determine the protein expression levels. In addition, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was employed to measure the rates of cell proliferation. The invasion and migration of the MCF-7 cells were examined using a Transwell® assay. The expression levels of lncRNA-AK058003 were increased significantly in the breast cancer tissues and were found to strongly correlate with the severity of the breast cancer clinical stage. Bioinformatics analysis revealed that the γ-synuclein gene (SNCG) may be a target gene regulated by lncRNA-AK058003. Thus, lncRNA-AK058803 was downregulated using small interfering RNA, and the mRNA and protein expression levels of SNCG were shown to be significantly reduced. Furthermore, the proliferation, invasion and migration rates of the MCF-7 breast cancer cells were significantly reduced. Therefore, the results demonstrated that unregulated lncRNA-AK058003 in breast cancer cells promotes cancer cell proliferation, invasion and metastasis via the regulation of SNCG expression.

Identification of γ-synuclein as a stage-specific marker in bladder cancer by immunohistochemistry

Background

Previous studies have shown that the expression level of γ-synuclein (SNCG) is associated with progression of many different malignant tumors. In this study, we discuss and assess the prognostic ability of SNCG in bladder cancer.

Material/Methods

Medical records (2005–2013) were retrospectively reviewed for the population of interest. SNCG expression was identified immunohistochemically from bladder cancer tissues of 113 bladder cancer patients. The survival rate was calculated by the Kaplan-Meier method. Cox proportional hazard regression model was used for analysis of predictors of bladder cancer.

Results

SNCG was overexpressed in bladder cancer tissues compared with the normal bladder tissues (p<0.0001). SNCG expression in bladder cancer tissue was strongly related to tumor stage. However, SNCG level was not a prognostic factor of survival.

Conclusions

Our results demonstrate that SNCG is highly expressed in bladder cancer tissue and its expression is stage-specific, but it is not helpful for predicting outcome in bladder cancer patients.

A peptide inhibitor of synuclein-γ reduces neovascularization of human endometriotic lesions

Endometriosis is a chronic painful gynecological condition characterized by adherence and growth of endometrium outside of the uterine cavity. Neovascularization is essential to the developing endometriosis lesion to support its growth. Synuclein-γ (SNCG), a protein implicated in cellular proliferation, is associated with a broad range of malignancies as well as endometriosis. We hypothesized that SNCG plays an important role in the neovascularization and growth of endometriosis and blocking of SNCG will interfere with survival of endometriotic lesions in a mouse model. We developed SP012, a novel 12 amino acid peptide inhibitor of SNCG. SP012 inhibited three-dimensional endothelial cell tube formation in a dose-dependent manner. Using intravital microscopy, SP012 was shown to be successfully delivered to human endometriotic lesions in a xenograft mouse model in vivo. Alymphoid (BALB/c-Rag2-/-Il2rγ-/- lacking T, B and NK cells) mice were surgically induced with human endometriotic lesions and treated with SP012 or phosphate-buffered saline control. SP012 treated endometriotic lesions had decreased growth, development and vascularization at the time of necroscopy. Endometriotic lesions treated with SP012 also had fewer isolectin (+) microvessels. These results, using a mouse model, indicate that SNCG plays a role in the neovascularization and subsequent growth of human endometriotic lesions. Targeting SNCG function using peptide inhibitor might provide a potential therapeutic option for the treatment of endometriosis in the future.

Correlation between periostin and SNCG and esophageal cancer invasion, infiltration and apoptosis

OBJECTIVE

To investigate the correlation between periostin and SNCG and esophageal cancer invasion, infiltration and apoptosis.

METHODS

A total of 78 cases esophageal surgical resection specimens were collected, expression of periostin and SNCG in esophageal cancer were detected. Effect of periostin and SNCG in esophageal carcinoma invasion and infiltration was analyzed.

RESULTS

The upregulated rate of periostin had significant difference in esophageal cancer tissues (39.74%), adjacent tissues (17.86%) and normal tissues (0.00%); The positive expression rates of SNCG had significant difference in esophageal cancer tissues (61.54%), adjacent tissues (32.14%) and normal tissues (1.96%); The upregulated rate of periostin had a significant correlation with lymph node metastasis, adventitia invasion, TNM stage; The positive expression rates of SNCG had a significant correlation with differentiation degree, lymph node metastasis, adventitia invasion, TNM stage; Apoptosis index of the positive of expression of SNCG of esophageal cancer tissue (4.541±2.267) was significantly lower than that of the negative expression (7.316±2.582) (P<0.05).

CONCLUSIONS

SNCG may play an important role in invasion, infiltration and apoptosis of esophageal cancer and serve as target spots in the targeted therapy of esophageal cancer.

Loss of caveolin-1 in prostate cancer stroma correlates with reduced relapse-free survival and is functionally relevant to tumour progression

Levels of caveolin-1 (Cav-1) in tumour epithelial cells increase during prostate cancer progression. Conversely, Cav-1 expression in the stroma can decline in advanced and metastatic prostate cancer. In a large cohort of 724 prostate cancers, we observed significantly decreased levels of stromal Cav-1 in concordance with increased Gleason score (p = 0.012). Importantly, reduced expression of Cav-1 in the stroma correlated with reduced relapse-free survival (p = 0.009), suggesting a role for stromal Cav-1 in inhibiting advanced disease. Silencing of Cav-1 by shRNA in WPMY-1 prostate fibroblasts resulted in up-regulation of Akt phosphorylation, and significantly altered expression of genes involved in angiogenesis, invasion, and metastasis, including a > 2.5-fold increase in TGF-β1 and γ-synuclein (SNCG) gene expression. Moreover, silencing of Cav-1 induced migration of prostate cancer cells when stromal cells were used as attractants. Pharmacological inhibition of Akt caused down-regulation of TGF-β1 and SNCG, suggesting that loss of Cav-1 in the stroma can influence Akt-mediated signalling in the tumour microenvironment. Cav-1-depleted stromal cells exhibited increased levels of intracellular cholesterol, a precursor for androgen biosynthesis, steroidogenic enzymes, and testosterone. These findings suggest that loss of Cav-1 in the tumour microenvironment contributes to the metastatic behaviour of tumour cells by a mechanism that involves up-regulation of TGF-β1 and SNCG through Akt activation. They also suggest that intracrine production of androgens, a process relevant to castration resistance, may occur in the stroma.

Clinical study of the relationship between γ-synuclein and the response of neoadjuvant chemotherapy in breast cancer

OBJECTIVES

To investigate relationships between several protein biomarkers and clinical responses to neoadjuvant chemotherapy (NAC) in breast cancer.

METHODS

Tumour tissue samples from female patients with locally advanced breast carcinoma (stages IIA to IIIC), treated with NAC regimens (including 5-fluorouracil, epirubicin, cyclophosphamide and docetaxel, epirubicin, cyclophosphamide) were analysed retrospectively. Immunohistochemical analysis was used to test for protein levels of oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor (HER)-2, protein 53 (p53) and γ-synuclein. Relationships between protein biomarkers and responses to NAC were analysed by multivariate logistic regression analysis.

RESULTS

Data from 154 patients (median age, 51 years; range 27-75 years) were included. Multivariate logistic regression analysis showed that γ-synuclein was an independent predictor of NAC objective response rate, and a statistically significant relationship was observed between NAC regimen, γ-synuclein levels and pathological complete response rate.

CONCLUSIONS

These study findings suggest that γ-synuclein - in combination with other markers such as ER, PR and HER-2 - may serve as a biomarker for response to NAC in breast cancer and warrants further study.

Synuclein-γ suppression mediated by RNA interference inhibits the clonogenicity and invasiveness of MCF-7 cells

The aim of the present study was to investigate the effects of synuclein-γ (SNCG) downregulation by RNA interference (RNAi) on the clonogenicity and invasiveness of MCF-7 breast cancer cells. This study used four pairs of SNCG-specific siRNAs which were designed and cloned into the pGPU6 plasmid for introduction into an MCF-7 cell line. The SNCG knockdown efficacies of the four siRNAs were compared using the reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemistry. The cells' clonogenic and invasive phenotypes were examined with clonogenic and Boyden chamber assays. In comparison with the non-specific siRNA and empty vector controls, all four SNCG siRNAs were observed to significantly inhibit SNCG expression at the mRNA and protein levels (F=481.06, P<0.001; F=147.42, P<0.0001). SNCG suppression mediated by RNAi successfully inhibited the clonogenicity (P=0.002) and invasiveness (P<0.001) of transfected MCF-7 cells. According to the results of the present study, we concluded that SNCG suppression mediated by RNAi significantly suppressed SNCG expression at the mRNA and protein levels, suggesting that SNCG suppression mediated by an RNAi strategy may become a novel approach for treating advanced breast cancer.