Human phospholipid scramblase 1 interacts with and regulates transactivation of HTLV-1 Tax

Human phospholipid scramblase (PLSCR) 1 expression is strongly activated in response to interferon (IFN) treatment and viral infection, and PLSCR1 is necessary for the IFN-dependent induction of gene expression and antiviral activity. We show here that PLSCR1 directly interacts with human T-cell leukemia virus type-1 (HTLV-1) Tax in vitro and in vivo. This interaction reduced the cytoplasmic distribution of Tax. PLSCR1 efficiently repressed the Tax-mediated transactivation of the HTLV-1 long terminal repeat and the NF-κB binding site reporter constructs in an interaction-dependent manner in COS-1 and Tax-producing HTLV-1-infected T cell lines. Furthermore, we show that PLSCR1 repressed the homodimerization of Tax in vitro. These data reveal for the first time that PLSCR1 specifically interacts with HTLV-1 Tax and negatively regulates its transactivation activity by altering the subcellular distribution and the homodimerization of Tax. PLSCR1 may play an important role in the IFN-mediated repression of Tax-dependent transactivation during HTLV-1 infection.     

抗多囊蛋白1氨基端单克隆抗体的制备和鉴定

目的 :用杂交瘤技术制备抗多囊蛋白 1胞外区氨基端的单克隆抗体 (mAb) ,并对其特异性进行鉴定。方法 :以肾组织总RNA为模板 ,用RT PCR扩增多囊蛋白 1胞外区氨基端的编码基因PKD1cDNA。将该基因克隆到融合蛋白表达载体pQE3 0中 ,转染大肠杆菌M15。以异丙基硫代半乳糖苷 (IPTG)诱导表达多囊蛋白 1胞外区氨基端的组氨酸融合蛋白 (PC1 e2 ) ,用亲和层析法纯化。以纯化的融合蛋白作为抗原免疫BALB/c小鼠 ,取小鼠脾细胞与小鼠骨髓瘤细胞株Sp2 / 0进行细胞融合 ,间接ELISA筛选阳性克隆 ,有限稀释法进行单克隆化。mAb的特异性用间接ELISA和Westernblot鉴定。结果 :克隆到两个编码多囊蛋白 1氨基端的cDNA片段 (50 2bp和 471bp)。构建的表达质粒经酶切和DNA测序证实 ,为所需要的质粒。表达出相对分子质量 (Mr)分别为 1980 0和 1890 0的融合蛋白 ,经Westernblot鉴定 ,均为多囊蛋白 1的融合蛋白。用Mr 为 1890 0的融合蛋白免疫小鼠 ,得到杂交瘤细胞株 7B1。Westernblot分析表明 ,该细胞株分泌的mAb能特异地与多囊蛋白 1氨基端结合。结论 :本实验表达了PKD1多拷贝区所编码的PC1 e2 ,成功地制备了抗多囊蛋白 1胞外区N端的mAb。     

大肠肿瘤中Tiam1的表达及临床意义

目的探讨T淋巴瘤侵袭转移诱导因子1(T lymphom a invasion and m etastasis induc ing factor 1,Tiam1)表达与大肠癌发生、发展和转移的关系。方法应用免疫组化方法检测大肠正常组织、大肠腺瘤、大肠癌和大肠淋巴结转移癌石蜡组织标本中Tiam1蛋白的表达情况。应用RT-PCR和免疫组化方法检测大肠癌细胞株中Tiam1 mRNA和蛋白的表达情况。结果Tiam1蛋白在大肠正常组织、腺瘤、癌及淋巴结转移癌中表达差异有显著性(2χ=23.561,P<0.01);两两比较发现,腺瘤Tiam1表达比大肠正常组织高(Z=-2.423,P<0.05),淋巴结转移癌组织Tiam1表达比大肠癌组织高(Z=-2.051,P<0.05),而大肠癌组织与腺瘤组织Tiam1表达差异无显著性(Z=-0.938,P>0.05)。在大肠癌组织中,伴发转移的大肠癌组织比未发生转移的大肠癌组织Tiam1表达明显增强,差异具有显著性(Z=-3.176,P<0.01)。RT-PCR结果显示Tiam1基因在高转移的LoVo和SW 620中呈高表达,在低转移的LS174T和HT29中呈低或不表达,在SW 480、HCT116等呈中度表达。结论Tiam1表达与大肠癌转移存在密切关系,Tiam1表达可作为大肠癌转移过程中一个有价值的指标。     

Asialoglycoprotein receptor interacts with the preS1 domain of hepatitis B virus in vivo and in vitro

Background

The preS1 domain of the large envelope protein has been identified as an essential viral structure involved in hepatitis B virus (HBV) attachment. However, the cellular receptor(s) for HBV has not yet been identified.

Aims

To identify a cell-surface receptor for HBV, which could elucidate the molecular mechanism of HBV infection.

Methods

A novel yeast two-hybrid system was used to screen proteins interacting with the preS1 region of HBV. Their interaction was verified by yeast cotransformation, coimmunoprecipitation and mammalian two-hybrid assay, while their intracellular and tissue localization was analyzed by confocal microscopy and immunohistochemistry, respectively.

Results

Asialoglycoprotein receptor (ASGPR) interacted specifically and directly with the preS1 domain of HBV in vivo and in vitro. The levels of expression of preS1 and ASGPR in the liver were similar and correlated with each other.

Conclusions

ASGPR is a candidate receptor for HBV that mediates further steps of HBV entry.     

小鼠CXCR3胞外N末端的可溶性表达及其抗体制备

目的 克隆小鼠CXCR3基因,将其胞外N末端在大肠杆菌中进行可溶性表达并用于抗体制备。方法采用RT-PCR技术,从Balb／c小鼠脾细胞中扩增出编码CXCR3的全长序列,将胞外N末端亚克隆人DsbA融合表达载体,转化大肠杆菌BL21(DE3),诱导表达后进行分离纯化,然后免疫家兔制备多克隆抗体,并用趋化小室法检测抗体对IP-10趋化小鼠T细胞作用的影响。结果获得编码小鼠CXCR3的cDNA序列,其胞外N末端与DsbA融合后能在大肠杆菌中可溶性表达,表达量达40％,其抗体可显著抑制IP-10对小鼠T细胞的趋化作用。结论获得小鼠趋化因子受体CXCR3胞外N末端融合蛋白及其抗体,抗体具有在体外抑制T细胞趋化的作用。     

肿瘤睾丸抗原OY-TES-1氨基端截短蛋白及其多克隆抗体的制备

目的获得原核表达的OY-TES-1氨基端截短蛋白(OY-TES-1-N),并制备其多克隆抗体。方法扩增编码OY-TES-1-N 268个氨基酸(A6-R273)的cDNA序列;将PCR产物插入原核表达载体pMAL-C2,构建重组质粒,并转化DH5α菌;通过蓝白斑筛选、DNA测序筛出阳性菌;在优化条件下用IPTG对阳性菌进行诱导表达MBP/OY-TES-1-N融合蛋白;上Amyloseresin亲和层析柱纯化,行Western blot鉴定。以融合蛋白作为抗原免疫新西兰白兔制备抗血清,经活化琼脂糖微球纯化后,采用ELISA法及Western blot法分别检测抗血清的效价和多克隆抗体的特异性。结果成功诱导表达出MBP/OY-TES-1-N融合蛋白。以该蛋白免疫新西兰兔制备抗血清,抗体效价为1∶1 000,Western blot检测证实该抗体能与目的蛋白发生特异性结合。结论成功地表达并纯化了MBP/OY-TES-1-N融合蛋白,并制备了特异性多克隆抗体。     

Studies of the DMP1 57-kDa functional domain both in vivo and in vitro

Dmp1-null mice and patients with mutations in dentin matrix protein 1 (DMP1) resulting in autosomal recessive hypophosphatemic rickets display similar skeletal defects. As mutations were observed in the last 18 amino acids of DMP1 in 1 subset of patients and as fragments of intact DMP1, a 37-kDa N-terminal and a 57-kDa C-terminal fragment, have been purified from bone and dentin, we hypothesized that the cleaved 57-kDa C-terminal fragment is the essential functional domain of DMP1. To test this hypothesis, different forms of recombinant DMP1 were expressed in 293EBNA, CHO and 2T3 cells. The results showed that DMP1 was processed into a 37-kDa N-terminal and a 57-kDa C-terminal fragment in vitro in all cell lines examined. DMP1 processing in CHO cells was blocked by a furin protease inhibitor, decanoyl-Arg-Val-Lys-Arg-chloromethyl ketone, in a dose-dependent manner. Coexpression of PHEX, a potential upstream protease, had no apparent effect on DMP1 cleavage in 293EBNA cells, suggesting that PHEX may not be required for DMP1 processing. To test the in vivo role of the C-terminal fragment, transgenic mice overexpressing full-length DMP1 or the 57-kDa fragment controlled by the 3.6-kb Col1 promoter were generated. Overexpression of these transgenes had no effect on the wild-type skeleton, but on the Dmp1-null background showed expression in the osteoblast layer and throughout the bone matrix leading to the rescue of the null bone phenotype. This suggests that the 57-kDa C-terminal fragment may be able to recapitulate the function of intact DMP1 in vivo.     

结直肠癌组织中CD10的表达及其临床意义

目的探讨结直肠癌组织中间质和上皮细胞CD10的表达及与肿瘤临床生物学行为的关系。方法运用免疫组化EnVision法检测90例结直肠癌组织和20例正常黏膜中CD10的表达,同时用α-SMA标记结直肠癌组织中肌纤维母细胞。结果正常结直肠黏膜中间质和上皮细胞均无CD10的表达,而在结直肠癌组织中,CD10在间质和上皮细胞的阳性表达率分别为57．8％和26．7％。结直肠癌中CD10阳性的间质细胞和上皮细胞在高、低级别癌中的表达差异无显著性（P〉0．05）;间质细胞CD10阳性在侵及肌层者高于侵及浆膜层者（P〈0．01）,而CD10阳性的上皮细胞与肿瘤的浸润深度无关（P〉0．05）;间质细胞和上皮细胞表达CD10与淋巴结转移均无相关性（P〉0．05）;CD10阳性间质细胞在有脉管侵犯者低于无脉管侵犯者（P〈0．01）,CD10阳性上皮细胞在有脉管侵犯者高于无脉管侵犯者（P〈0．01）。CD10阳性间质细胞与α-SMA阳性间质细胞分布一致。结论结直肠癌中间质细胞肌纤维母细胞化可阻止肿瘤的转移,而肿瘤细胞表达CD10可能通过促进细胞外基质溶解而促进转移。     

Topical ocular levocabastine reduces ICAM-1 expression on epithelial cells both in vivo and in vitro

Background Levocabastine is a selective topical H₁ antagonist, effective in the treatment of seasonal allergic rhinitis and conjunctivitis. Objective We evaluated the possible effects of levocabastine eye drops on early (EPR) and late phase (LPR) inflammatory changes induced by allergen-specific conjunctival challenge (ASCC). We focused our attention on the possible effect of levocubastine on expression of the intracellular adhesion molecule-1 (ICAM-1) on epithelial cells. Such a phenomenon is likely to play an important role in allergic inflammation. Methods The study was a double-blind, placebo-controlled, randomized trial, performed in cross-over, outside the pollen season. Ten out-patients suffcring from allergic rhinoconjunctivitis due to Parietaria Judaica (wall parietary) were enrolled. Patients randomly received levocabastine eye drops (0.5 mg/mL) or placebo eyedrops, one drop in the left eye (right eye as control), 30 min before ASCC. Clinical evaluation (hyperaemia, burning-itching, lacrimation and eyelid swelling) and cytological assessment (number of neutrophils, eosinophils and lymphocytes, and ICAM-1 expression on conjunctival epithelium) were evaluated at baseline, 30min and 6h after ASCC. In parallel, we evaluated the in vitro effect of levocabastine at concentrations ranging from 2 × 10^?9 M to 2 × 10^?5M on ICAM-l expression and shedding by a continuously cultured differentiated epithelial cell line (WK). Results Levocabastine reduced symptom scores during EPR (15min and 30min, P < 0.002), inflammatory cell infiltration duritig FPR (P < 0.002 for neutrophils, eosinophils and lymphocytes) and ICAM-1 expression on epithelium both during EPR (P < 0.002) and LPR (P < 0.02). LPR symptom scores and inflammatory cell infiltration were only slightly modified by levocabastine treatment. In vitro levocabastine at 2 ± 10^?5 M concentration was able to down-regulate basal ICAM-1 expression, although it exerted no effect on ICAM-1 expression by interferon-γ (IFNγ)-stimulated WK cells and on soluble ICAM-1 release by epithelium. Conclusion Levocabastine exerts anti-allcrgJc activity, in that it reduces in vivo inflammatory cell infiltration due to ASCC, and also adhesion molecule expression on conjunctival epithelium. The latter phenomenon may be due, at least in part, to a direct effect of levocabastine on epithelial cells.     

RASSF1A及其在肿瘤发生中的作用

RASSF1A（Ras-assotiation domain family 1 A）基因是一个新型抑癌基因。目前的研究已经在许多肿瘤中发现了这个基因的失活。虽然这个基因的失活可因基因缺失或突变引起，但最常见的原因还是该基因的启动子区甲基化紊乱。这种表形遗传学改变被证实是肿瘤形成的一个早期事件，是肿瘤形成的主要因素之一。RASSF1A有多个结构域，被认为是一种潜在的Ras癌蛋白效应分子，能与活化的Ras结合，调节凋亡及细胞周期信号通路，在细胞的凋亡、增殖、分化及维持细胞的稳定中发挥多种生物学效应，与肿瘤的发生发展密切相关。     

A monoclonal antibody directed against the homologous N-terminal domain of glycophorin A and B

A monoclonal antibody (iB5, IgG1 kappa) reacting with human red cells was produced after immunization of BALB/C mice with cord red cells, followed by fusion of the spleen cells with the murine myeloma cell line Ag 8-653. The monoclonal antibody agglutinated blood group N+ much better than M + N-red cells but did not recognize erythrocytes from rare individuals typed as M + N-S-s-U- and those from an En(a-) individual (M.E.P.). However, S-s-U- donors typed as M + N + or M-N+ and En(a-) red cells from donor G.W. were agglutinated. The erythrocyte receptors for iB5 are completely destroyed by papain treatment and significantly decreased by neuraminidase. Interestingly also, the iB5 antibody failed to agglutinate trypsin-treated N+M-S-s-U- erythrocytes. Other investigations have shown that the monoclonal antibody precipitated glycophorin A and B from N+ red cells and only glycophorin B from M+N-erythrocytes. The reactivity of iB5 was further explored by immunostaining following the electrophoretic transfer to nitrocellulose sheets of membrane proteins from common (M and N) and rare erythrocytes [En(a-),S-s-U-, MgMg, McM, St(a+), Mi.V, Mi.III, Tn] separated by SDS-polyacrylamide gel electrophoresis. These studies have clearly demonstrated that the monoclonal iB5 antibody is directed against the homologous N-terminal domain of glycophorin A and B, a specificity which explains the serological reactivity of iB5 against common and rare erythrocytes.     

CDH1基因多态与结直肠癌和肝癌发生、进展的关系

目的 探讨CDH1基因C-160A多态与结直肠癌(colorectal cancer,CRC)和肝细胞癌(hepatocellular carcinoma,HCC)发病风险和肿瘤分级分期的关系.方法 采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法 检测374例CRC与324名对照以及180例HCC与209名对照的CDH1 C-160A基因型分布及差异.结果 CDH1 C-160A基因型分布在CRC-对照和HCC-对照人群间差异均无显著性(P>0.05).然而,高TNM分期(Ⅲ Ⅳ)CRC组中A基因型(CA AA)频率显著低于低TNM分期者(Ⅰ Ⅱ)(P=0.008);淋巴结转移阳性CRC组中A基因型频率显著低于转移阴性者(P=0.016);远处转移阳性CRC组中A基因型频率也低于转移阴性者,但差异无统计学意义(P=0.169).高T分期(T2～T4)HCC组中A基因型频率低于T1期者,但差异未达到统计学意义(P=0.066).结论 CDH1 C-160A与CRC和HCC的发病风险无关,但-160A可能对CRC肿瘤进展具有保护作用.     

Evolution of DNA ploidy state and DNA index in colorectal adenomas and carcinomas using the crypt isolation technique: new hypothesis in colorectal tumorigenesis

The evolution of DNA diploid, aneuploid and multiploid (diploid and aneuploid) states that represent DNA types that are independent of genetic alterations in colorectal tumors were examined. Changes in the DNA index (DI) accompanying tumor development from adenoma to carcinoma were assessed. In colorectal adenomas and early cancers, the DNA was diploid or multiploid. A pure aneuploid state was observed in advanced carcinomas only, whereas the aneuploid DI values of adenomas were characterized by two distinct peaks. The DI values for the carcinomas were randomly distributed. However, in advanced carcinomas, aneuploid carcinomas tended to have lower DI whereas aneuploid populations within multiploid carcinomas tended to have higher DI. Early cancers were subdivided into two groups: a cancer region associated with an adenomatous region (group A tumors) and a cancer region that exhibited an absence of or a very limited adenomatous region (group B tumors). Group A tumor DI were lower than group B. It is suggested that low DI adenomas might transform into group A tumors, which consequently progress to advanced aneuploid carcinomas. In addition, group B tumors might derive predominantly from high DI adenomas or from group A tumors by high DI evolution, and might progress into advanced multiploid carcinomas. Therefore, the evolution of the DNA index might play an important role in the development of colorectal tumors.     

Medroxyprogesterone acetate enhances in vivo and in vitro antibody production

In the present study we examine the effects of medroxyprogesterone acetate (MPA) on the specific antibody secretion to T-dependent antigens. Our results show that the in vivo administration of MPA to mice, 7 or 90 days before immunization with sheep red blood cells (SRBC), significantly enhanced both, primary and secondary antibody responses, without affecting delayed-type hypersensitivity (DTH). These effects could be counteracted by the anti-progestin onapristone or ZK 98299 (ZK) suggesting that MPA interacted with progesterone (PRG) receptors to increase B-cell response. To better understand the mechanisms involved in MPA activity we carried out cultures of splenocytes, bone marrow cells or lymph node cells from immunized mice in the presence of MPA, and evaluated the amount of antibody release to supernatants. We found that low doses of MPA (10(-9) M and 10(-10) M) significantly enhanced the in vitro production of specific immunoglobulin G (IgG) antibodies, an effect that appears to involve the interaction of the progestin with PRG receptors, as judged by the inhibition of MPA effects with ZK (10(-8) M) or RU486 (10(-9) M). These receptors were detected by flow cytometry analysis in a proportion of T lymphocytes. Because MPA did not increase the number of immunoglobulin-secreting cells, our findings suggest that MPA enhanced the capacity of individual cells to produce specific immunoglobulin.     

肿瘤转移相关蛋白1的表达与人直肠癌组织淋巴管转移及预后关系

目的观察肿瘤转移相关蛋白1(MTA1)与直肠癌淋巴结转移及预后的关系,探讨MTA1在直肠癌发生发展过程中的作用。方法应用免疫组化法和实时荧光定量PCR方法检测MTA1在45例人直肠癌和20例直肠息肉组织中的表达,并结合临床病理特征和生存资料进行相关分析。结果直肠癌组织中MTA1蛋白及mRNA的表达较直肠息肉组显著增加(P<0.05),MTA1表达与直肠癌淋巴结转移、Dukes临床分期密切相关(P<0.05)。MTA1阳性表达与生存率负相关(P<0.05)。结论 MTA1高表达促进直肠癌淋巴结转移,检测MTA1表达可成为直肠癌预后不良的重要指标。     

Correlation between in vitro tetraploidy in skin fibroblasts and development of sporadic colorectal carcinomas

In vitro tetraploidy (IVT) in skin fibroblasts cultures measured by flow cytometry was compared with histological type and degree of dysplasia in 22 patients with adenomas of the colon and rectum. Furthermore, IVT was compared with stage and differentiation in 36 patients with carcinoma of the colon and rectum. In vitro tetraploidy in skin fibroblasts was correlated to type as well as dysplasia in adenomas and differentiation in carcinomas but was not correlated to Dukes' stage in carcinomas. Skin fibroblast genetic instability, expressed as increased IVT (IVT+), has been reported to reflect a genetic predisposition to colorectal cancer in the hereditary nonpolyposis colorectal cancer syndrome. Because IVT+, which appears to be associated with the progression of adenomas to carcinomas, also is found in many of the non-syndrome colorectal cancers, we suggest that development of colorectal cancer is considerably influenced by the constitutive genetic instability of the autosomal dominant colorectal cancer syndromes.     

Cyclooxygenase-2 in sporadic colorectal polyps: immunohistochemical study and its importance in the early stages of colorectal tumorigenesis

Cyclooxygenase-2 (COX-2) is one of the important targets for the chemoprevention of colorectal cancer by non-steroidal anti-inflammatory drugs (NSAIDs). To evaluate the role of COX-2 in early stages of colorectal tumorigenesis, we immunohistochemically investigated the frequency and localization of COX-2 in sporadic colorectal polyps that showed various histology using a commercially available monoclonal antibody. A total of 105 colorectal polyps were examined. These included 33 low-grade adenomas (LGAs), 28 high-grade adenomas (HGAs), 32 HGAs with p53 overexpression (HGAs-p53), and 12 cases of carcinoma in adenoma (CIA). Regarding the immunohistochemical expression of p53, MIB-1, and CD63, histological classification was made for each case. COX-2 was expressed in neoplastic epithelial cells and interstitial macrophages that were distributed mainly in the superficial areas of polyps. COX-2 labeling indices (LIs) were 8.2% in LGAs, 6.3% in HGAs, 0.9% in HGAs-p53, and 0.6% in the carcinomatous components of CIAs. COX-2 LIs were significantly higher in adenomas, including LGAs and HGAs, than in HGAs-p53 and CIAs (p < 0.001). Within CIAs, significantly higher COX-2 LIs were obtained in the adenomatous components than in the carcinomatous components (p < 0.05). The size of polyps was not correlated with COX-2 expression irrespective of their histology. The results show that COX-2 might be involved in early stages of colorectal tumorigenesis. Colorectal adenomas could be a target for the chemopreventive strategy irrespective of their sizes.     

Renal cell carcinomas and pancreatic adenocarcinomas produce nidogen in vitro and in vivo

The production of nidogen by four renal cell carcinoma (RCC) and three pancreatic adenocarcinoma (PAc) cell lines has been studied in cell culture and in xenografted tumours in nude mice. In RCC cells, immunoreactivity for nidogen was seen only after exposure to monensin to induce cytoplasmic accumulation of secretory proteins. In PAc cells, immunoreaction was also detectable in control cells. Immunoblotting of control and monensin-exposed cells and immunoprecipitation of culture media of radioactively labelled cells demonstrated the production of nidogen polypeptide of M_r ca. 150000 by six of the seven cell lines. Basement membranes (BMs) and stroma of the xenografted tumours derived from these six cell lines demonstrated immunoreactivity for both human and mouse nidogen, as revealed with species-specific antibodies. The ability of the cells to produce nidogen in vitro and deposit in vivo was positively correlated with high histological grade of the xenografted tumours, although the small number of cell lines studied calls for further studies to confirm this. The distribution of nidogen in human RCC and PAc specimens was also studied by immunohistochemistry. There was strong immunoreactivity for nidogen in tumour stroma, BM of carcinoma cell nests, and endothelial basal lamina, but no conclusions could be drawn regarding histological grade and immunostaining patterns, because stromal production could not be ruled out. The results show that nidogen is produced by human carcinoma cells both in vitro and in vivo. Copyright © 1999 John Wiley & Sons, Ltd.