口腔鳞癌发展过程中抑癌基因PTEN的蛋白表达及意义

目的：探讨抑癌基因PTEN(phosphatase and tensin homologue deleted on chromosome ten)在口腔鳞癌(oral squamous cell cancer，OSCC)发展过程中的蛋白表达及临床病理意义。方法：应用免役组化S—P法检测10例正常口腔粘膜、10例上皮单纯增生、15例上皮异常增生及32例OSCC组织中抑癌基因PTEN的蛋白表达情况，同时结合患者的临床病理资料进行分析。结果：正常口腔粘膜和上皮单纯增生组织中VTEN蛋白全部阳性表达；上皮异常增生组织中PTEN蛋白阳性表达率为93．3％；OSCC组织中PTEN蛋白的阳性表达率为71．9％，其中高、中、低分化OSCC组织中PTEN蛋白的阳性表达率分别为85．7％、75％和33．3％。PTEN在OSCC组织中的蛋白表达与患者的性别、年龄无明显相关性，但与组织分化程度明显相关。结论：OSCC组织(尤其低分化)中PTEN蛋白的阴性表达率较高．说明PTEN基因突变或缺失在OSCC的发生、发展过程中起重要作用。     

PTEN抑癌基因转染粘液表皮样癌细胞系M3SP2的建立和鉴定

目的：为了研究外源性基因PTEN对粘液表皮样癌细胞生物学行为的影响，建立稳定表达PTEN的粘液表皮样癌细胞系。方法：应用脂质体介导方法将野生型PTEN基因导入高转移性粘液表皮样癌细胞系M3SP2，嘌呤霉素筛选阳性克隆，用免疫印迹法和ABC免疫酶染色法检测转染细胞中PTEN蛋白的表达。结果：野生型PTEN基因成功地导入细胞M3SP2，转染细胞稳定表达PTEN蛋白，PTEN蛋白分布于细胞质。结论：M3SP2细胞能稳定表达外源性基因PTEN。     

外源性PTEN抑癌基因对高转移性黏液表皮样癌细胞系形态的影响

目的 :观察外源野生型PTEN基因对高转移性黏液表皮样癌细胞系形态的影响。方法 :应用倒置显微镜观察法、HE染色观察、扫描电镜及透射电镜观察法 ,比较野生型PTEN抑癌基因转染的黏液表皮样癌细胞M 3SP2 PTEN与对照的黏液表皮样癌细胞M 3SP2 pBp的形态学差异。 结果 :M 3SP2 pBp细胞体外生长活跃 ,细胞数量多 ,核分裂相多 ,细胞表面微绒毛丰富 ,细胞核切迹明显 ,细胞质中线粒体丰富 ;M 3SP2 PTEN细胞生长缓慢 ,分裂相很少 ,细胞数量少 ,部分细胞空泡变性 ,染色质凝集 ,细胞膜彭出 ,线粒体数量少并发生肿胀 ,较多的溶酶体融合。结论 :外源野生型PTEN基因的转染能导致体外培养的高转移性黏液表皮样癌细胞变性、坏死或凋亡。     

Current view: intestinal stem cells and signaling

Studies using mice have yielded significant amounts of information regarding signaling pathways, such as Wnt, bone morphogenic protein, PtdIns(3,4,5) kinase, and Notch, involved in intestinal development and homeostasis, including stem cell regulation and lineage specification and maturation. However, attempts to model signals definitively that control intestinal stem cells have been difficult because of a long-standing and recently reenergized debate surrounding their location. Although crypt-based columnar cells have been recently shown to display self-renewal and multipotential capacity, a large body of evidence supports long-term label-retaining cells, located on average at the +4 position just above the Paneth cells, as putative stem cells. Herein, we propose that both these cell types represent true intestinal stem cells maintained in different states (quiescent vs actively cycling), presumably via interactions with different microenvironments. Finally, we review current findings regarding the roles of Wnt, bone morphogenic protein, PtdIns(3,4,5) kinase, and Notch pathways within the intestine.     

Ginkgetin Blocks Constitutive STAT3 Activation and Induces Apoptosis through Induction of SHP‐1 and PTEN Tyrosine Phosphatases

Ginkgetin, a biflavone from Ginkgo biloba leaves, is known to exhibit antiinflammatory, antifungal, neuroprotective, and antitumor activities, but its precise mechanism of action has not been fully elucidated. Because the aberrant activation of STAT3 has been linked with regulation of inflammation, proliferation, invasion, and metastasis of tumors, we hypothesized that ginkgetin modulates the activation of STAT3 in tumor cells. We found that ginkgetin clearly suppressed constitutive phosphorylation of STAT3 through inhibition of the activation of upstream JAK1 and c‐Src kinases and nuclear translocation of STAT3 on both A549 and FaDu cells. Treatment with sodium pervanadate reversed the ginkgetin‐induced down‐modulation of STAT3, thereby indicating a critical role for a PTP. We also found that ginkgetin strongly induced the expression of the SHP‐1 and PTEN proteins and its mRNAs. Further, deletion of SHP‐1 and PTEN genes by siRNA suppressed the induction of SHP‐1 and PTEN, and reversed the inhibition of STAT3 activation. Ginkgetin induced apoptosis as characterized by an increased accumulation of cells in subG1 phase, positive Annexin V binding, loss of mitochondrial membrane potential, down‐regulation of STAT3‐regulated gene products, and cleavage of PARP. Overall, ginkgetin abrogates STAT3 signaling pathway through induction of SHP‐1 and PTEN proteins, thus attenuating STAT3 phosphorylation and tumorigenesis. Copyright © 2016 John Wiley & Sons, Ltd.     

胃腺癌中PYGOPUS2和PTEN的表达及相关性研究

目的检测胃腺癌中PYGOPUS2和PTEN的表达特点,探讨二者在不同临床特征中表达的意义。方法以95例胃腺癌作为观察组,以70例非肿瘤的胃黏膜组织作为对照组,采用免疫组织化学方法检测2组中PYGOPUS2和PTEN的表达。结果观察组中PYGOPUS2表达的阳性率明显高于对照组(P0.05),PTEN表达的阳性率明显低于对照组(P0.05)。观察组中PYGOPUS2和PTEN的表达均与淋巴结转移、脉管浸润和Ki67表达密切相关(P均0.05)。PYGOPUS2的表达与肿瘤的直径和分化程度密切相关(P均0.05),而PTEN的表达与肿瘤的直径和分化程度无明显相关性。线性相关分析显示PYGOPUS2和PTEN的表达未见明显相关性。生存分析显示PYGOPUS2和PTEN的表达与预后相关(P均0.05)。结论胃腺癌组织中PYGOPUS2高表达、PTEN低表达对肿瘤的发生和进展均有一定促进作用,PYGOPUS2和PTEN之间未见明显协同作用。术后联合检测PYGOPUS2和PTEN的表达对判断胃腺癌的预后有一定价值。     

miR-19通过靶向PTEN调节PI3K-Akt通路促进子宫内膜癌KLE细胞 的侵袭和迁移

目的：分析miR-19对PTEN及PI3K-Akt通路的调节作用,揭示miR-19和PTEN对子宫内膜癌KLE细胞侵袭、迁移的影响及其机制。方法：收集2017年5月至2020年8月河北医科大学第一医院收治的74例子宫内膜癌患者经手术切除（术前未接受放化疗等治疗）且病理确诊为子宫内膜癌的肿瘤组织及对应癌旁组织,采用qPCR和WB法检测PTEN在子宫内膜癌组织中的表达水平以及转染miR-19模拟物或抑制物对KLE细胞中PTEN表达的影响。通过TargetScan及双荧光素酶报告基因实验预测并验证PTEN是否为miR-19的靶基因,将KLE细胞随机分为对照（NC）组、miR-19模拟物组和miR-19+PTEN组,分别转染阴性对照片段（miR-NC）、miR-19 模拟物或共转染 miR-19 模拟物+PTEN 过表达载体,采用 Transwell 和细胞划痕实验检测 miR-19 和PTEN对KLE细胞迁移和侵袭能力的影响,WB法检测对PI3K-Akt通路相关蛋白表达的影响。结果：子宫内膜癌组织中PTEN的mRNA和蛋白表达水平均明显低于癌旁组织（均P<0.01）。miR-19能与PTEN mRNA的3’-UTR特异性结合,上调miR-19的表达能抑制PTEN的mRNA和蛋白的表达,下调miR-19的表达则出现相反的结果（均P<0.01）。与miR-NC组相比,miR-19 模拟物组的迁移、侵袭细胞数以及划痕愈合率均显著升高（均 P<0.01）,而 miR-19+PTEN 组的细胞迁移和侵袭能力以及划痕愈合率较miR-19摸拟物组则明显降低（均P<0.01）;与miR-NC 组相比,miR-19 模拟物组中 PTEN 蛋白的表达明显降低,而p-Akt 308和p-Akt 473蛋白的表达明显升高,Akt蛋白的表达无明显变化（均P<0.01）;而在miR-19+PTEN组中,p-Akt 308和p-Akt 473蛋白的表达均明显低于miR-19模拟物组（均P<0.01）。结论：miR-19可能通过抑制PTEN的表达从而活化PI3K-Akt通路,进而促进子宫内膜癌KLE细胞的迁移和侵袭。     

Pathophysiological significance of N‐myc downstream‐regulated gene 2 in cancer development through protein phosphatase 2A phosphorylation regulation

N‐myc downstream‐regulated gene 2 (NDRG2) is a candidate tumor suppressor in various cancers, including adult T‐cell leukemia/lymphoma (ATLL). NDRG2, as a stress‐responsive protein, is induced by several stress‐related signaling pathways and NDRG2 negatively regulates various signal transduction pathways. Although it has not been found to function alone, NDRG2 binds serine/threonine protein phosphatase 2A (PP2A), generating a complex that is involved in the regulation of various target proteins. The main function of NDRG2 is to maintain cell homeostasis by suppressing stress‐induced signal transduction; however, in cancer, genomic deletions and/or promoter methylation may inhibit the expression of NDRG2, resulting in enhanced tumor development through overactivated signal transduction pathways. A wide variety of tumors develop in Ndrg2‐deficient mice, including T‐cell lymphoma, liver, lung and other tumors, the characteristics of which are similar to those in Pten‐deficient mice. In particular, PTEN is a target molecule of the NDRG2/PP2A complex, which enhances PTEN phosphatase activity by dephosphorylating residues in the PTEN C‐terminal region. In ATLL cells, loss of NDRG2 expression leads to the failed recruitment of PP2A to PTEN, resulting in the inactivation of PTEN phosphatase with phosphorylation, ultimately leading to the activation of PI3K/AKT. Thus, NDRG2, as a PP2A adaptor, regulates the global phosphorylation of important signaling molecules. Moreover, the downregulation of NDRG2 expression by long‐term stress‐induced methylation is directly correlated with the development of ATLL and other cancers. Thus, NDRG2 might be important for the development of stress‐induced leukemia and other cancers and has become an important target for novel molecular therapies.