γ突触核蛋白与肿瘤耐药

γ突触核蛋白(SNCG)在许多肿瘤晚期高表达,包括乳腺癌、卵巢癌、前列腺癌、肺癌、肝癌、食管癌、直肠癌等.SNCG与BubR1相互作用损害有丝分裂检测点引起肿瘤增殖、转移和耐药.以SNCG为靶向的人工合成肽段ANK能抑制SNCG的活性,有望成为肿瘤化疗的辅助手段.     

宫颈癌组织突触核蛋白-γ表达与临床病理因素相关性分析

目的:探讨神经γ突触核蛋白(SNCG)在子宫颈癌、宫颈不典型增生及正常组织中的表达。方法:用免疫组化SP法检测73例子宫颈癌、36例宫颈不典型增生和18例慢性宫颈炎组织中SNCG的表达情况。结果:宫颈癌组织SNCG的阳性率为65.8%(48/73),而宫颈不典型增生SNCG的阳性率为36.1%(13/36),正常组织中未见SNCG的表达。在低分化、中等分化及高分化的宫颈癌组织中,SNCG的阳性率分别为89.3%(25/28)、66.7%(20/30)及20.0%(3/15)。肿瘤组织分化程度越低,SNCG的阳性率越高;SNCG在Ⅰ期肿瘤组织中表达阳性率为35.0%(7/20),Ⅱ期为66.7%(20/30),Ⅲ期为91.3%(21/23),肿瘤组织临床分期越晚SNCG的阳性率越高。结论:SNCG蛋白在宫颈癌的发生、发展过程中起着重要的作用,肿瘤分期越晚阳性率越高,SNCG有望成为新的宫颈癌的肿瘤标志,为预后判断和制定相应的治疗方案提供依据。     

神经突触核蛋白的生物学特性及其与肿瘤关系的研究进展

神经突触核蛋白（synuclein,SNCG）是一种主要在神经组织中表达的高度保守的可溶性小分子蛋白。近年来的研究发现在雌激素敏感的宫颈癌和乳腺癌,雄激素敏感的前列腺癌,消化系统肿瘤以及肺癌等肿瘤组织中均有SNCG的表达。特别是在多数进展期的肿瘤组织中特异性高表达。SNCG可在肿瘤恶性程度评价、预后判断及抗肿瘤药物的筛选以及肿瘤的个体化治疗方案的制定中发挥重要作用。     

组织因子途径抑制物-2和γ-神经突触核蛋白在食管癌中的表达及其与肿瘤细胞浸润、转移和凋亡之间的关系

目的:探讨组织因子途径抑制物-2(tissue factor pathway inhibitor-2 ,TFPI-2)和γ-神经突触核蛋白(synuclein gamma,SNCG)在食管癌组织中的表达及其与肿瘤浸润、转移和细胞凋亡之间的关系.方法:应用免疫组织化学法检测82例食管癌组织及20例相应癌旁不典型增生组织和54例相应癌旁正常食管组织中TFPI-2、SNCG和基质金属蛋白酶-9(matrix metalloproteinase-9 ,MMP-9)的表达,应用TUNEL法检测肿瘤细胞的凋亡并计算细胞凋亡指数(apoptosis index,AI).结果: TFPI-2和SNCG在食管癌组织、癌旁不典型增生组织及正常食管组织中的阳性表达率分别为30.4%、60.0%、87.0%和63.4%、30.0%、3.7%,3组间两两比较差异均有统计学意义(P<0.01).TFPI-2和SNCG的表达与肿瘤淋巴结转移、浸润深度、TNM分期和分化程度密切相关(P<0.01),但与患者年龄、性别、肿瘤大小、肿瘤部位和肿瘤大体分型无关(P>0.05).食管癌组织中TFPI-2与MMP-9的表达呈负相关(r=-0.636,P=0.000),而SNCG与MMP-9的表达呈正相关(r=0.393,P=0.000).TFPI-2和SNCG的表达与AI有关 (P<0.05).结论:TFPI-2可能通过抑制MMP-9的表达诱导细胞凋亡,抑制食管癌细胞的生长和转移,而SNCG可能在此过程中起着相反的作用, TFPI-2和SNCG有望成为有效的肿瘤标志物和肿瘤基因治疗的新靶点.     

SNCG、 nm23在胃癌中的表达及临床意义

目的:研究胃癌中SNCG,nm23的表达及其临床意义,并进一步探讨它们在胃癌中表达的相关性.方法: 采用免疫组化法观察60例胃癌及20例胃正常黏膜石蜡标本中SNCG、 nm23的表达情况,实验数据用SPSS12.0软件包进行统计.结果: 在胃癌中SNCG蛋白阳性率65%,高于周围正常组织(P<0.05).nm23在胃癌组织中表达阳性率为55%,低于周围正常组织(P<0.01).SNCG、 nm23的表达与肿瘤浸润深度、淋巴结转移及肿瘤临床分期均相关(P<0.05).SNCG与nm23在胃癌中的表达呈负相关(P<0.05)).结论: SNCG、 nm23蛋白的表达与胃癌发生、发展和浸润转移相关.胃癌组织中SNCG的表达与nm23的表达呈负相关,二者的检测有助于胃癌浸润转移的预测,对判断患者预后有重要参考价值.     

γ-synuclein在乳腺癌中的表达及意义

目的:探讨SNCG在乳腺癌不同时期的表达及其意义.方法:收集90例乳腺癌,15例良性乳腺病变和10例正常乳腺组织石蜡标本,用免疫组织化学方法检测SNCG表达情况.结果:SNCG在正常乳腺组织和良性肿瘤中未见表达,在乳腺癌中阳性率为38.9%(35/90),其中在早期(O/Ⅰ/Ⅱ期)乳腺癌中有轻度表达,达10.9%(6/55),在晚期(Ⅲ/Ⅳ期)浸润性乳腺癌中有高表达,阳性率达80.8%(29/35).SNCG表达在癌细胞胞浆中,且以癌巢周边组织表达明显.结论:SNCG蛋白过表达与乳腺癌进程有关,在晚期浸润癌中表达较早期更高,SNCG蛋白表达标志乳腺癌细胞更具侵袭性和转移性.SNCG有望成为新的乳腺癌肿瘤标志物,可为预后判断和制定相应的治疗方案提供依据.     

mTOR通路激活后上调SNCG表达水平抑制 乳腺癌细胞辐射 敏感性的研究

目的：探讨乳腺癌T47D细胞通过激活mTOR通路调控SNCG表达水平，从而抑制乳腺癌细胞辐射敏感性的分子机制。方法：检测不同剂量γ射线照射后的T47D乳腺癌细胞中mTOR蛋白表达水平。在细胞培养液中加入不用浓度磷脂酸（PA，mTOR通路激活剂）进行培养，以常规培养细胞为对照组，采用Western blot法检测对照组和激活剂组细胞SNCG蛋白的表达。对照组和激活组细胞采用4 Gy γ射线照射24 h，检测照射后SNCG mRNA和蛋白的表达情况，并采用平板细胞克隆形成实验检测克隆形成率。同时，将转染SNCG siRNA的乳腺癌T47D细胞株分成激活组和对照组，验证SNCG在乳腺癌细胞辐射敏感性抵抗中的生物学功能。结果：不同剂量射线照射后，mTOR蛋白表达水平显著升高。mTOR激活剂PA处理后的细胞对乳腺癌细胞放射敏感性具有明显的抑制作用，同时Western blot显示γ射线照射处理后的乳腺癌细胞中SNCG蛋白的表达水平异常。Western blot和qPCR方法检测发现，T47D对照组和干扰SNCG基因的T47D细胞实验组中，激活mTOR或γ射线照射均能引起SNCG蛋白和mRNA表达增加。克隆形成实验进一步证明，降低SNCG的表达可显著抑制T47D细胞克隆形成能力。结论：在乳腺癌细胞中，mTOR介导的SNCG表达调控对乳腺癌细胞抗辐射起着重要作用，降低SNCG的表达可提高辐射敏感性，提示在临床治疗中有可能通过使用SNCG抑制剂或mTOR抑制剂提高乳腺癌细胞在放化疗中的敏感性。     

SNCG在肝癌高/低淋巴道转移细胞株中的差异性表达

目的:研究SNCG蛋白在小鼠肝癌高/低淋巴道转移潜能细胞株中的定位和表达差异。方法:应用免疫细胞化学、Western blot方法检测SNCG蛋白在小鼠肝癌高/低淋巴道转移潜能细胞株Hca-F/Hca-P的定位情况和表达差异。结果:SNCG蛋白在Hca-F和Hca-P细胞株中均主要定位于细胞浆,细胞核区域也可见少量蛋白表达。SNCG在Hca-F中的表达［染色强度为(+++)］强于在Hca-P中的表达［染色强度为(++)］。检测到一条SNCG特异性蛋白条带,在Hca-F细胞中表达量为Hca-P细胞中的1.9倍。结论:SNCG的高表达可能与高淋巴道转移潜能有关。     

胃癌组织中SNCG和CXCR4 mRNA的表达及临床意义

  目的  研究SNCG和CXCR4在胃癌和正常胃黏膜组织中的表达,探讨其在胃癌发生、发展、浸润转移中的作用。  方法  应用RT-PCR法检测不同组织中SNCG和CXCR4 mRNA的表达情况。  结果  SNCG和CXCR4 mRNA在胃癌组织中的表达量明显高于正常胃黏膜组织（P < 0.01）;胃癌组织中SNCG mRNA的表达量与癌组织的浸润深度和淋巴结转移有关（P < 0.05,P < 0.01）,CXCR4mRNA的表达量与淋巴结转移有关（P < 0.01）;胃癌组织中SNCG mRNA与CXCR4 mRNA的表达量呈正相关（r=0.346,P < 0.05）。  结论  SNCG和CXCR4在胃癌组织中高表达,可能与胃癌的发生、发展、浸润、转移密切相关。      

原位杂交法检测SNCG在乳腺组织中的表达

目的:检测乳腺癌相关基因SNCG在乳腺组织不同病变的阳性表达率,分析其表达规律,探讨其在乳腺癌发生、发展中的作用。方法:用原位杂交方法,以地高辛标记的SNCG反义mRNA作探针,检测167例乳腺不同病变组织中SNCG基因mRNA的表达情况,并进行统计学分析。结果:SNCG的阳性表达率在乳腺增生症为76.0%(38/50),纤维腺瘤为20.0%(3/15),非典型性增生为92.3%(12/13),乳腺癌组织为95.5%(85/89),并且表达强度不同。有淋巴结转移的乳腺癌中强阳性表达率为47.7%(21/44)。而乳腺增生症组中无强阳性表达者。SNCG在不同乳腺病变组织中的表达有统计学意义(P<0.001)。结论:SNCG作为一个新发现的乳腺癌相关基因,在乳腺不同病变中表达情况不同,随病变程度加重,表达率明显增高。有转移者表达强度明显增强。因而SNCG可作为判断乳腺癌恶性潜能的指标。     

Neuronal protein synuclein gamma predicts poor clinical outcome in breast cancer

Synuclein gamma (SNCG), previously identified as a breast cancer-specific gene (BCSG1), is highly expressed in breast carcinomas but not in normal epithelium. SNCG regulates many pathways in growth and progression of breast cancer. To determine if SNCG is a biomarker for clinical prognosis of breast cancer, we generated a panel of murine monoclonal antibodies (mAbs) against human SNCG and correlated SNCG protein expression in 358 clinical breast cancer specimens with clinical outcome. A panel of 14 mAbs was characterized by ELISA, immunoprecipitation (IP), Western blot, immunocytochemistry and immunohistochemistry. SNCG protein expression was determined in 438 clinical breast specimens by immunohistochemical analysis using mAb 5C5. Expression of SNCG was strongly correlated with the stage, lymph node involvement, metastasis, tumor size and Her-2 status, but its expression was not associated with ER and PR expression status. While 71.4% of advanced breast cancers were positive for SNCG expression, only 26.8% of Stage I/II breast cancers were positive for SNCG expression and 5.2% of benign hyperplasia expressed SNCG. SNCG protein was not detectable in normal tissue adjacent to breast cancer. After a median follow-up of 64 months, patients with an SNCG-positive tumor had a significantly shorter disease-free survival and overall survival and a high probability of death compared no expression of SNCG. Multivariate analysis demonstrated that SNCG was a strong independent prognostic variable. SNCG is a new unfavorable prognostic marker for breast cancer progression and a potential target for breast cancer treatment.     

Synuclein Gamma Inhibits the Mitotic Checkpoint Function and Promotes Chromosomal Instability of Breast Cancer Cells

Summary Aberrant expressions of the neuronal protein synuclein gamma (SNCG) in malignant mammary epithelial cells are strongly associated with the progression of breast cancer. SNCG is not expressed in normal breast tissues but abundantly expressed in a high percentage of invasive and metastatic breast carcinomas. Several studies have demonstrated that SNCG expression significantly stimulates proliferation, invasion, and metastasis of breast cancer cells. To elucidate the molecular and cellular mechanisms underlying the tumorigenic functions of SNCG, we investigated the effects of SNCG expression on the mitotic checkpoint function of breast cancer cells. By conducting several different lines of investigations, we now demonstrate that SNCG expression in breast cancer cells overrides the mitotic checkpoint control and confers the cellular resistance to anti-microtubule drug-caused apoptosis. We further show that the inhibitory effects of SNCG on mitotic checkpoint can be overthrown by enforced overexpression of the mitotic checkpoint protein BubR1 in SNCG-expressing cells. These new findings combined with our previous observation that SNCG intracellularly associates with BubR1 together suggest that SNCG expression compromises the mitotic checkpoint control by inhibition of the normal function of BubR1, thereby promoting genetic instability. Genetic instability is recognized as an important contributing factor in tumorigenesis. Hence, our studies gain insight into the mechanisms whereby SNCG expression advances breast cancer disease progression and fasters tumor metastasis.     

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.     

Expression of neuronal protein synuclein gamma gene as a novel marker for breast cancer prognosis

Synucleins are emerging as central players in the fundamental neural processes and in the formation of pathologically insoluble deposits characteristic of neurodegenerative diseases. However, synuclein γ (SNCG), previously identified as a breast cancer specific gene (BCSG1), is also highly expressed in breast carcinomas, but not expressed in normal or benign breast tissues. We analyzed SNCG gene expression in 93 clinical breast specimens and associated it with clinical outcome. Overall SNCG mRNA expression was detectable in 36% breast cancers. However, 81% of stage III/IV breast cancers were positive for SNCG expression, while only 15% of stage I/II breast cancers were positive for SNCG expression. In contrast, SNCG was undetectable in benign breast lesions. Expression of SNCG in the primary tumor also significantly associated with lymph node involvement and metastasis. There was no significant correlation between SNCG gene expression and age, menstruation, and status of ER, PR, PCNA, and HER-2. Patients whose tumors expressed SNCG had a significantly shorter DFS and a high probability of death when compared with those whose tumors did not express SNCG. The hazard ratio of metastasis or recurrence according to the SNCG status was 4.515 (95% CI, 1,188–17.154; P = 0.027). Cox multivariate analysis showed that SNCG had independent prognostic significance above and beyond conventional variables. This study suggests that the expression of SNCG is an independent predictive marker for recurrence and metastasis in breast cancer progression. SNCG is expected to be a useful marker for breast cancer progression and a potential target for breast cancer treatment.     

Hypomethylation of the synuclein gamma gene CpG island promotes its aberrant expression in breast carcinoma and ovarian carcinoma

Recent studies indicate that synuclein gamma (SNCG) gene, located in chromosome 10, participates in the pathogenesis of the breast and ovary. SNCG, also known as breast cancer-specific gene 1 (BCSG1), is not expressed in normal mammary or ovarian surface epithelial cells but is highly expressed in the vast majority of advanced staged breast and ovarian carcinomas. When overexpressed, SNCG significantly stimulates breast cancer proliferation and metastasis. To fully understand the molecular mechanisms underlying the abnormal expression of SNCG in neoplastic diseases, in this study, we extensively examined the methylation status of a CpG island located in exon 1 of SNCG gene in a panel of breast and ovarian tumor-derived cell lines to determine whether DNA methylation plays a crucial role in SNCG expression. In vivo bisulfite DNA sequencing of genomic DNA isolated from breast cancer cell lines showed that the 15 CpG sites within the CpG island were completely unmethylated in all SNCG-positive cell lines (5 of 5), but were densely and heterogeneously methylated in the majority of SNCG-negative cell lines (3 of 4). The methylation occurred primarily at the CpG sites 2, 5, 7, and 10-15. Similarly, we observed a strong correlation of hypomethylation of the CpG island and SNCG expression in ovarian cancer cell lines (5 of 5). Intriguingly, the methylation pattern in ovarian cancer cells is different from that in breast cancer cells. In SNCG-nonexpressing ovarian cancer cells, all 15 of the CpG sites were completely methylated instead of selective methylation at certain sites shown in breast cancer cells, thereby suggesting a tissue-specific methylation pattern. A correlation between hypomethylation of the exon 1 and expression of SNCG mRNA was also observed in primary breast tumor tissues. The importance of DNA methylation in the control of SNCG expression in cancer cells is further strengthened by demonstration of re-expression of SNCG mRNA in SNCG-negative ovarian and breast cancer cells with a demethylating agent 5-aza-2'-deoxycytidine. In addition, we demonstrate that inhibition of cell growth leads to a decreased mRNA expression and an increased DNA methylation of SNCG gene. Taken together, these new findings strongly suggest that DNA hypomethylation is a common mechanism underlying the abnormal expression of this candidate oncogene in breast and ovarian carcinomas.