Mass spectrometry-based N-glycoproteomics for cancer biomarker discovery

Glycosylation is estimated to be found in over 50% of human proteins. Aberrant protein glycosylation and alteration of glycans are closely related to many diseases. More than half of the cancer biomarkers are glycosylated-proteins, and specific glycoforms of glycosylated-proteins may serve as biomarkers for either the early detection of disease or the evaluation of therapeutic efficacy for treatment of diseases. Glycoproteomics, therefore, becomes an emerging field that can make unique contributions to the discovery of biomarkers of cancers. The recent advances in mass spectrometry (MS)-based glycoproteomics, which can analyze thousands of glycosylated-proteins in a single experiment, have shown great promise for this purpose. Herein, we described the MS-based strategies that are available for glycoproteomics, and discussed the sensitivity and high throughput in both qualitative and quantitative manners. The discovery of glycosylated-proteins as biomarkers in some representative diseases by employing glycoproteomics was also summarized.     

HPV16型E7复制型DNA疫苗诱发的抗肿瘤免疫反应

为了研制有效的疫苗 ,用于HPV16型重度感染和与其感染相关的宫颈癌晚期病人手术后的免疫治疗 ,用复制型DAN疫苗载体 pSCA1,在其CMVIE启动子之下插入修饰的HPV16型E7基因mE7- 3( 2 4G、2 6G、6 7R) ,构建成 pSCA1mE7- 3复制型DNA疫苗。以重组质粒免疫C5 7BL/ 6小鼠 ,检测诱发的特异性CTL活性 ;将免疫后的小鼠用TC - 1肿瘤细胞攻击 ,观察免疫保护效果。实验结果显示 :pSCA1mE7- 3复制型DNA疫苗能诱导小鼠产生针对TC - 1肿瘤细胞的特异性CTL反应 ;复制型DNA疫苗免疫后的小鼠能耐受 1× 10 4 TC - 1细胞的攻击 ,成瘤时间推迟 ,并且成瘤率明显下降 ,部分小鼠得到保护能免受肿瘤攻击。因此pSCA1mE7- 3复制型DNA疫苗可作为HPV16相关肿瘤的癌前病变及中晚期病人术后免疫治疗的候选疫苗。     

Soil seed bank in different vegetation types in the Loess Plateau region and its role in vegetation restoration

In the Loess Plateau region, soil erosion is a serious problem. Vegetation restoration is an effective approach to control soil erosion and improve ecosystems. The soil seed bank generally plays an important role in vegetation restoration after disturbance. Thus, we reviewed soil seed bank studies to reveal the soil seed bank characteristics and its role in vegetation restoration in three vegetation types (forest, forest‐steppe, and steppe). We selected 38 seed bank studies and analyzed several seed bank characteristics, such as seed density, species composition, and the relationship between seed size and seed bank. We also assessed the role of the soil seed bank in vegetation restoration. The soil seed bank density ranged from 2,331 ± 1,993 to 6,985 ± 4,047 seeds/m² among the different vegetation types. In the soil seed bank, perennial herbs and grasses accounted for 51.5% of the total species. Native species that were dominant or common in the standing vegetation usually had relatively high seed bank densities. Moreover, species with smaller seeds generally had higher soil seed bank densities. The present study indicates that the soil seed bank plays a significant role in spontaneous vegetation restoration, especially during the early successional stages in abandoned slope farmlands and grazing‐excluded grasslands. However, species with large seeds or transient soil seed banks should be reintroduced through seeding to accelerate target species restoration. More studies on soil seed banks need to be conducted to comprehensively reveal their characteristics.     

Cholesterol enhances neuron susceptibility to apoptotic stimuli via cAMP/PKA/CREB-dependent up-regulation of Kv2.1

Cholesterol is a major component of membrane lipid rafts. It is more abundant in the brain than in other tissues and plays a critical role in maintaining brain function. We report here that a significant enhancement in apoptosis in rat cerebellar granule neurons (CGNs) was observed upon incubation with 5mM K(+) /serum free (LK-S) medium. Cholesterol enrichment further potentiated CGN apoptosis incubated under LK-S medium. On the contrary, cholesterol depletion using methyl-beta-cyclodextrin protected the CGNs from apoptosis induced by LK-S treatment. Cholesterol enrichment, however, did not induce apoptosis in CGNs that have been incubated with 25mM K(+) /serum medium. Mechanistically, increased I(K) currents and DNA fragmentation were found in CGNs incubated in LK-S, which was further potentiated in the presence of cholesterol. Cholesterol-treated CGNs also exhibited increased cAMP levels and up-regulation of Kv2.1 expression. Increased levels of activated form of PKA and phospho-CREB further supported activation of the cAMP/PKA pathway upon treatment of CGNs with cholesterol-containing LK-S medium. Conversely, inhibition of PKA or small G protein Gs abolished the increase in I(K) current and the potentiation of Kv2.1 expression, leading to reduced susceptibility of CGNs to LK-S and cholesterol-induced apoptosis. Our results demonstrate that the elevation of membrane cholesterol enhances CGN susceptibility to apoptotic stimuli via cAMP/PKA/CREB-dependent up-regulation of Kv2.1. Our data provide new evidence for the role of cholesterol in eliciting neuronal cell death.     

氯化镧对玉米根切段钾离子外渗影响的动力学研究

研究了氯化镧对玉米(Zea mays L.)“京早8号”根切段细胞膜透性及质子分泌的影响,并用动力学方法研究了钾离子外渗过程的变化。氯化镧处理可降低外渗液的电导率及K~ 和糖的外渗量,使质子分泌活动增强。用动力学方法分析玉米根切段K~ 外渗过程的结果表明:(1)应用于K~ 吸收研究的数学模型也能适应于K~ 外渗的研究;(2)在LaCl_3和(或)CaCl_2存在的条件下,最大吸收速度(V_(max))升高,而米氏常数(K_m)没有变化;(3)在LaCl_3和(或)CaCl_2存在的条件下,K~ 外渗量降低是由于最大吸收速度(V_(max))升高所致。     

Interference with SMO increases chemotherapy drug sensitivity of A2780/DDP cells by inhibiting the Hh/Gli signaling pathway

Aberrant activation of the Hedgehog (Hh)/Gli pathway contributes to the tumorigenesis of several human cancers, including ovarian cancers. We investigated the function of SMO on cell growth, drug resistance, and invasive ability in A2780/DDP cells. Moreover, we also tested the levels of the downstream target genes of the Hh/Gli pathway in SMO short hairpin RNA (shRNA) lentivirus-infected A2780/DDP cells. Western blot analysis results revealed that the Hh/Gli pathway was activated in cisplatin-resistant A2780/DDP cells. After infection by SMO shRNA lentivirus, the colony formation rate and invasive rate of cisplatin-resistant A2780/DDP cells were decreased. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that upon transfection with SMO shRNA, cell growth was decreased and drug sensitivity to cisplatin was upregulated. Moreover, interference with SMO decreased the expression of MMP-2, MMP-9, VEGF, and Snail in cisplatin-resistant cells. Thus, the Hh/Gli signaling pathway was aberrantly activated in A2780/DDP cells. The colony formation rate and invasive rate were decreased in SMO shRNA lentivirus–infected A2780/DDP cells. All results showed that inhibiting Hh/Gli signaling may negatively regulate the proliferation, invasion, and metastasis of cisplatin-resistant A2780/DDP cells, as well as increase the sensitivity of A2780/DDP to the chemotherapeutic drug of cisplatin.