The RND protein is involved in the vulnibactin export system in Vibrio vulnificus M2799

Vibrio vulnificus, an opportunistic marine bacterium that causes a serious, often fatal, infection in humans, requires iron for its pathogenesis. This bacterium exports vulnibactin for iron acquisition from the environment. The mechanisms of vulnibactin biosynthesis and ferric-vulnibactin uptake systems have recently been reported, while the vulnibactin export system has not been reported. Mutant growth under low-iron concentration conditions and a bioassay of the culture supernatant indicate that the VV1_0612 protein plays a crucial role in the vulnibactin secretion as a component of the resistance-nodulation-division (RND)-type efflux system in V. vulnificus M2799. To identify which RND protein(s) together with VV1_0612 TolC constituted the RND efflux system for vulnibactin secretion, deletion mutants of 11 RND protein-encoding genes were constructed. The growth inhibition of a multiple mutant (Δ11) of the RND protein-encoding genes was observed 6 h after the beginning of the culture. Furthermore, ΔVV1_1681 exhibited a growth curve that was similar to that of Δ11, while the multiple mutant except ΔVV1_1681 showed the same growth as the wild-type strain. These results indicate that the VV1_1681 protein is involved in the vulnibactin export system of V. vulnificus M2799. This is the first genetic evidence that vulnibactin is secreted through the RND-type efflux systems in V. vulnificus.     

Xenophagy in Helicobacter pylori‐ and Epstein–Barr virus‐induced gastric cancer

Helicobacter pylori and Epstein–Barr virus (EBV) account for roughly 80% and 10%, respectively, of gastric carcinomas worldwide. Autophagy is an evolutionarily conserved and intricately regulated cellular process that involves the sequestration of cytoplasmic proteins and organelles into double‐membrane autophagosomes that eventually fuse with lysosomes for degradation of the engulfed content. Emerging evidence indicates that xenophagy, a form of selective autophagy, plays a crucial role in the pathogenesis of H. pylori‐ and EBV‐induced gastric cancer. Xenophagy specifically recognizes intracellular H. pylori and EBV and physically targets these pathogens to the autophagosomal–lysosomal pathway for degradation. In this connection, H. pylori or EBV‐induced dysregulation of autophagy may be causally linked to gastric tumourigenesis and therefore can be exploited as therapeutic targets. This review will discuss how H. pylori and EBV infection activate autophagy and how these pathogens evade recognition and degradation by the autophagic pathway. Elucidating the molecular aspects of H. pylori‐ and EBV‐induced autophagy will help us better understand the pathogenesis of gastric cancer and promote the development of autophagy modulators as antimicrobial agents. Published by John Wiley & Sons, Ltd     

The mutational burdens and evolutionary ages of early gastric cancers are comparable to those of advanced gastric cancers

Early gastric cancers (EGCs) precede advanced gastric cancers (AGCs), with a favourable prognosis compared to AGC. To understand the progression mechanism of EGC to AGC, it is required to disclose EGC and AGC genomes in mutational and evolutionary perspectives. We performed whole‐exome sequencing and copy number profiling of nine microsatellite (MS)‐unstable (MSI‐H) (five EGCs and four AGCs) and eight MS‐stable (MSS) gastric cancers (four EGCs and four AGCs). In the cancers, we observed well‐known driver mutations (TP53, APC, PIK3CA, ARID1A, and KRAS) that were enriched in cancer‐related pathways, including chromatin remodelling and tyrosine kinase activity. The MSI‐H genomes harboured ten times more mutations, but were largely depleted of copy number alterations (CNAs) compared to the MSS cancers. Interestingly, EGC genomes showed a comparable level of mutations to AGC in terms of the number, sequence composition, and functional consequences (potential driver mutations and affected pathways) of mutations. Furthermore, the CNAs between EGC and AGC genomes were not significantly different in either MSI‐H and MSS. Evolutionary analyses using somatic mutations and MSI as molecular clocks further identified that EGC genomes were as old as AGC genomes in both MSS and MSI‐H cancers. Our results suggest that the genetic makeup for gastric cancer may already be achieved in EGC genomes and that the time required for transition to AGC may be relatively short. Also, the data suggest a possibility that the mutational profiles obtained from early biopsies may be useful in the clinical settings for the molecular diagnosis and therapeutics of gastric cancer patients. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

ABCC11/MRP8 Expression in the Gastrointestinal Tract and a Novel Role for?Pepsinogen Secretion

ATP-binding cassette (ABC) transporters are involved in chemotherapy resistance. Multidrug-resistance protein 8 (ABCC11/MRP8) is also involved in 5-fluorouracil (5-FU) metabolism. 5-FU and its derivatives are widely used in the treatment of gastrointestinal tract cancers, but little is known about the contribution of ABCC11/MRP8 to gastrointestinal tract and related cancers. Here, we report our investigation of ABCC11/MRP8 expression in normal and cancerous gastrointestinal tract tissues and reveal its novel role in the gastric mucosa. In tissue microarray and surgically resected cancer specimens, immunohistochemical (IHC) staining revealed significantly reduced expression of ABCC11/MRP8 in gastrointestinal tract cancers compared with other cancers. In contrast, strong ABCC11/MRP8 expression was observed in normal gastric mucosa. Additional immuno­fluorescence assays revealed co-localization of ABCC11/MRP8 and pepsinogen I in normal gastric chief cells. Quantitative PCR and Western blot analysis also revealed significant expression of ABCC11/MRP8 in fundic mucosa where the chief cells are mainly located. Furthermore, the ABCC11 mRNA-suppressed NCI-N87 gastric cancer cell line failed to secret pepsinogen I extracellularly. Thus, low expression of ABCC11/MRP8 is consistent with chemotherapeutic regimens using 5-FU and its derivatives in gastrointestinal tract cancers. Our results indicated a novel function of ABCC11/MRP8 in the regulation of pepsinogen I secretion in the normal gastric chief cells.     

胃癌中异常表达剪接因子的生物信息学分析及功能

目的 采用生物信息学方法分析胃癌中有表达差异的剪接因子,研究异常表达的富含丝氨酸苏氨酸蛋白家族中的剪接因子10(SRSF10)对胃癌细胞表型的影响。方法 通过癌症基因组图谱数据库(TCGA)下载胃癌以及癌旁组织的RNA-seq数据,对其采用生物信息学方法进行分析,最终得到胃癌中差异表达的剪接因子。从中挑选出SRSF10研究其对胃癌发生发展的影响,利用RNA干扰技术构建SRSF10敲低的胃癌细胞,同时采用MTS、Transwell以及细胞划痕方法研究敲低SRSF10后对胃癌细胞表型的影响。结果 胃癌中差异表达的剪接因子有48个,其中表达上调35个,表达下调13个。挑选表达上调的剪接因子SRSF10进行进一步研究,发现SRSF10敲低后的胃癌细胞与正常胃癌细胞相比增殖减慢,迁移能力降低,划痕愈合能力下降。结论 胃癌患者中存在较多有表达差异的剪接因子,可能在胃癌发生发展中起到重要作用。剪接因子SRSF10在胃癌发生发展中可能发挥重要的作用。     

MicroRNA-494对胃癌细胞增殖、细胞周期及凋亡的影响

目的?探讨microRNA-494（miR-494）对胃癌细胞增殖、细胞周期及凋亡的影响。方法?选取2015年1月—2018年1月被陕西省肿瘤医院收治并行手术切除的60例患者的胃癌组织及对应癌旁组织（距肿瘤边缘>2?cm）标本。将胃癌细胞MGC803分为miR-494组和对照组。采用PCR检测胃癌组织及体外培养细胞中的miR-494表达水平。在MGC803细胞中过表达miR-494,采用MTT法检测细胞增殖,流式细胞术检测细胞周期及细胞凋亡。PCR及Western blotting检测miR-494潜在靶点Cyclin D1的表达变化。结果?癌旁组织miR-494相对表达量较胃癌组织高（P?<0.05）。不同肿瘤直径、TNM分期miR-494相对表达量比较,差异有统计学意义（P?<0.05）。对照组MGC803细胞miR-494相对表达量较miR-494组低（P?<0.05）。miR-494组OD值较对照组低（P?<0.05）。对照组CyclinD1 mRNA和蛋白相对表达量较miR-494组高（P?<0.05）。miR-494与CyclinD1免疫组织化学评分呈负相关（r?=-0.469,P?<0.05）。结论?胃癌组织中miR-494表达水平降低,过表达miR-494能通过下调Cyclin D1的表达发挥抑制胃癌细胞增殖和细胞周期进展的作用。     

山东沿海地区Graves病患者糖调节异常特点分析

目的 探讨山东沿海地区汉族Graves病（GD）患者糖调节状态变化,并比较抗甲状腺药物治疗不同阶段糖调节状态变化特点.方法 选取2010年8月至2012年6月山东大学齐鲁医院收治的来自山东沿海地区的Graves病患者106例,男性45例,女性61例,平均年龄（34 ±5）岁.按患者所处治疗阶段分为3组,即初治组（GD1组,35例）、治疗期组（GD2组,37例）和减量期组（GD3组,35例）,并选取年龄相当的30名健康体检者作为对照（NC组）.入选患者均继续接受正规抗甲状腺药物治疗6个月,分别于治疗前后作口服葡萄糖耐量试验（OGTT）、胰岛素释放试验（InsRT）,观察血糖、胰岛素、早相胰岛素分泌指数（△I30/△G30）,OGTT血糖曲线下面积（GAUC）和InsRT胰岛素曲线下面积（INSAUC）的变化.应用方差分析进行数据比较.结果 基线时,GD各组空腹血糖水平显著低于NC组（F =29.85,P ＜0.05）;OGTT后血糖、胰岛素水平显著高于NC组（F=22.54、87.96,均P＜0.05）;GD各组△I30/△G30显著低于NC组（F=17.22,P＜0.05）;GAUC、INSAUC均显著高于NC组（F=79.09、112.77,均P＜0.05）;GD各组间相比,GD1、GD2组血糖、胰岛素水平显著高于GD3组（F=17.19、48.88,均P＜0.05）;治疗6个月后,GD各组血糖、胰岛素均显著低于基线水平（F=13.06、55.72,均P＜0.05）;GAUC、INSAUC均显著低于基线水平（F=53.08、96.98,均P＜0.05）.结论 沿海地区GD患者存在糖调节异常,主要特点是胰岛素早期分泌时相受损,高胰岛素血症;甲状腺功能正常后糖调节改善,糖耐量异常减轻和高胰岛素血症改善,但胰岛素早期分泌时相并无明显改善.     

幽门螺杆菌阴性胃癌的研究现状与思考

幽门螺杆菌阴性胃癌（HpNGC）是一种不同于幽门螺杆菌阳性胃癌（HpPGC）的疾病实体,在定义、诊断、临床病理特征、预后上具有独特性。HpNGC发病率低、临床病例资料少,国内尚缺乏相关研究。因此,本文做一综述,阐明其研究现状,以期增加对HpNGC的认识与关注,同时也为后继研究提供一定的参考。     

胃内亮蓝嵴和白色不透明物质与胃黏膜肠上皮化生相关性分析

目的评估胃内亮蓝嵴（light blue crest, LBC）、白色不透明物质（white opaque substance, WOS）等内镜下表现对胃黏膜肠上皮化生（gastric mucosa intestinal metaplasia, GIM）的诊断效能。方法纳入既往确诊为慢性萎缩性胃炎行胃镜早癌筛查患者,白光观察后行NBI-ME观察,并取活检病理确诊,比较胃内LBC及WOS的出现与GIM发生的相关性,分析LBC及WOS对GIM的诊断价值。结果共101例患者被纳入研究,GIM发病率为52.48%。LBC阳性组和LBC阴性组的GIM的发生率分别为71.74%和36.36%,两组间发生率差异有统计学意义（P＜0.0001）;WOS阳性组和WOS阴性组的GIM发生率分别为72.73%和50%,两组间GIM发生率差异无统计学意义（P＞0.05）;LBC、WOS均阳性或任一阳性与LBC、WOS均阴性GIM的发病率分别为70.37%和31.91%,两组间GIM发生率差异有统计学意义（P＜0.0001）。联合使用LBC及WOS的ROC曲线下面积为0.692（95%CI：0.587～0.797）。结论胃内LBC、WOS均阳性或任一阳性与GIM的组织学诊断有很强的相关性,可作为临床内镜下判断GIM的有效方法。胃黏膜萎缩类型及幽门螺杆菌（Hp）是否感染与GIM无明显相关性。