Suppression of murine breast cancer metastasis by selective inhibition of CXCR4 by synthetic polypeptide derived from viral macrophage inflammatory protein II

Stromal cell-derived factor-1 and its receptor CXC chemokine receptor-4 (CXCR4) have been implicated in breast cancer metastasis. A significant association between HER2 and CXCR4 expression has been observed in human breast tumor tissues, and overexpression of CXCR4 is essential for HER2-mediated tumor metastasis. Moreover, CXCR4 expression is low in normal breast tissues and high in malignant tumors, suggesting that a blockade of CXCR4 may limit tumor metastasis. The present study investigated the action of a synthetic antagonist 21-mer peptide derived from viral macrophage inflammatory protein II against CXCR4 (NT21MP) in inhibiting metastasis in vitro and in vivo. The results showed that chemotaxis of SKBR3 cells toward SDF-1α was reduced by NT21MP in a dose-dependent manner (P < 0.05). NT21MP inhibited tumor growth at 500 μg/kg and in combination with Herceptin, the anti-HER2 antibody. The in vivo metastatic assay showed that NT21MP significantly inhibited pulmonary metastasis, and the number of metastatic tumor nodes on the surface of the lung was greatly decreased. Compared with the saline-treated control group, PCNA expression was dose-dependently decreased by NT21MP, the percentage of apoptotic cells was increased, and CXCR4 mRNA and protein expression were downregulated. In conclusion, NT21MP inhibits cellular prolifer-ation, promotes apoptosis by downregulating CXCR4 expression, and suppresses the progression of primary and metastatic tumors. CXCR4 may be a useful therapeutic target for breast cancer, and NT21MP may serve as a potential target drug for the treatment of breast cancer metastasis.     

海参寡肽:免疫调节作用及机制研究

 为研究海参寡肽对小鼠的免疫调节作用及机制,试验选取250只SPF级雌性BALB/c小鼠,随机分为5组:空白对照组,乳清蛋白组(0.30 g/kg),0.15、0.30、0.60 g/kg海参寡肽组。连续灌胃30 d后,通过测定ConA诱导的小鼠淋巴细胞转化实验、迟发型变态反应、抗体生成细胞、血清溶血素水平、小鼠碳廓清实验、小鼠腹腔巨噬细胞吞噬鸡红细胞实验、自然杀伤(NK)细胞活性,观察海参寡肽对小鼠细胞免疫、体液免疫、单核-巨噬细胞吞噬和NK细胞活性的影响,并通过流式细胞术对脾脏T淋巴细胞亚群进行分析。结果表明:海参寡肽显著提高了小鼠细胞免疫、体液免疫、单核-巨噬细胞吞噬功能及NK细胞活性(P<0.05),且效果优于乳清蛋白。通过T淋巴细胞亚群分析表明,海参寡肽显著提高了脾脏CD3⁺百分比和CD4⁺百分比(P<0.05)。由此可知,海参寡肽可能通过增加T淋巴细胞数和Th细胞比例,介导细胞免疫、体液免疫功能、单核-巨噬细胞吞噬能力和NK细胞活性的增强作用,起到增强免疫功能的效果。     

ABCA2: a candidate regulator of neural transmembrane lipid transport

Studies in the past years have implicated multispan transmembrane transport molecules of the ATP binding cassette (ABC) transporter family in cellular lipid export processes. The prototypic ABC transporter ABCA1 has recently been demonstrated to act as a major facilitator of cellular cholesterol and phospholipid export. Moreover, the transporter ABCA4 (ABCR) plays a pivotal role in retinaldehyde processing, and ABCA3 has recently implicated in lung surfactant processing. These pioneering observations have directed considerable attention to the A subfamily of ABC proteins. ABCA2 is the codefining member of the ABC A-transporter subclass. Although known for some time, it was not until recently that its complete molecular structure was established. Unlike other ABC A-subfamily members, ABCA2 is predominantly expressed in the brain and neural tissues. The unique expression profile together with available structural data suggest roles for this largest known ABC protein in neural transmembrane lipid export. Received 31 January 2002; received after revision 11 March 2002; accepted 11 March 2002     

Change in sensitivity to lipopolysaccharide during the differentiation of human monocytes to macrophages in vitro

Mononuclear phagocytes in distinct differentiation stages and cultured under different conditions were tested for their sensitivity towards lipopolysaccharide (LPS), using procoagulant activity (PCA) expression and tumor necrosis factor (TNF) production as indices. The response of mature monocyte-derived macrophages differed from that of freshly isolated monocytes 1) by higher levels of constititive PCA, 2) by responding to approximately 1,000-fold lower concentrations of LPS with PCA and TNF production, and 3) by a faster rise in PCA and TNF production. Due to the high constitutive level of PCA expression, the PCA stimulation index for LPS was low in macrophages when compared with that in monocytes. Thus, during differentiation to macrophages, human monocytes acquire increased sensitivity to LPS (2 orders of magnitude more sensitive than a sensitive turbidimetricLimulus amoebocyte lysate assay). This exquisite sensitivity to LPS is expressed regardless of whether LPS is offered in the presence or absence of lipopolysaccharide binding protein-containing serum. This points to as yet uncharacterized pathways of high affinity interaction between LPS and macrophages.     

绵羊布鲁氏菌侵染小鼠巨噬细胞的荧光表征与分析

通过对绿色荧光蛋白(GFP)布鲁氏菌16M(强毒株)和M5(弱毒株)侵染小鼠巨噬细胞及胞内溶酶体、内质网、高尔基体初次结合所用时间进行测定,探讨二者在结合所用时间上是否存在差异;其次比较GFP布鲁氏菌16M和M5与胞内各细胞器结合产生的荧光强度。将GFP布鲁氏菌16M(强毒株)和M5(弱毒株)分不同时间段分别侵染RAW 264.7(细菌和细胞比例为100︰1),利用激光共聚焦显微镜和流式细胞仪观察和检测。结果表明:布鲁氏菌16M和M5侵染初期10 min时进入巨噬细胞,1.5 h时布鲁氏菌到达溶酶体,2.0 h时布鲁氏菌到达内质网和高尔基体。结果提示,布鲁氏菌16M和M5在侵染进入宿主细胞与胞内各细胞器初次结合所用时间相同,但布鲁氏菌16M与各细胞器结合的荧光强度均高于布鲁氏菌M5。以此推断布鲁氏菌16M进入胞内的数量高于布鲁氏菌M5。     

化学发光法研究大白兔外周血巨噬细胞中呼吸爆发随年龄的变化

首次建立了检测兔外周血巨噬细胞化学发光的方法,探索了在不同受体刺激剂,例如刀豆蛋白Con A、PMA、N-FMLP等作用下巨噬细胞化学发光信号的变化。实验表明,巨噬细胞化学发光信号随受体刺激剂浓度的提高增大,并在一定条件下与细胞的浓度成线性关系。化学发光试剂鲁米诺的浓度在5×10^-4mol/L、受体刺激剂的浓度在150μg时化学发光强度最大。4种不同的细胞稀释液中,含1% BSA的HBSS用于化学发光的缓冲溶剂效果最佳。应用这一方法对机体年龄增长过程中细胞呼吸爆发程度的变化进行了细致和深入的研究,探索了机体年龄增长与巨噬细胞呼吸爆发间的相互关系。     

胰岛炎症导致的2型糖尿病发病过程的动力学模型及治疗策略

为了揭示胰岛炎症导致2型糖尿病发生发展的机制,建立胰岛 β 细胞和巨噬细胞相互作用的数学模型,包括IL-1β 的产生和巨噬细胞的浸润过程,研究高浓度葡萄糖和游离脂肪酸对IL-1β 的共同作用,揭示胰岛炎症在2型糖尿病进程中的动力学机理.通过对模型中动力学参数的敏感性分析,提出针对不同患病情况的可能的优化治疗策略.     

Ikaros negatively regulates inducible nitric oxide synthase expression in macrophages: Involvement of Ikaros phosphorylation by casein kinase 2

Ikaros is known as a critical regulator of lymphocyte development. We examined the regulatory role of Ikaros in LPS/IFN-gamma-induced inducible nitric oxide synthase (iNOS) expression by macrophages. Our results showed that IK6 (Ikaros dominant negative isoform) induction increases the iNOS expression. Ikaros DNA binding activity on the iNOS promoter was decreased, and a mutation of the Ikaros-binding site on the iNOS promoter resulted in an increase in LPS/IFN-gamma-induced iNOS expression. LPS/IFN-gamma increased the histone (H3) acetylation on the Ikaros DNA binding site. These results suggest that Ikaros acts as a negative regulator on iNOS expression. Treatment with a casein kinase 2 (CK2) inhibitor reversed LPS/IFN-gamma-induced decrease in Ikaros DNA binding activity. Moreover, overexpression of kinase-inactive CK2 decreased iNOS expression and a significant amount of CK2alpha1 translocated into the nucleus in LPS/IFN-gamma-treated cells. Overall, these data indicate that LPS/IFN-gamma decreases the Ikaros DNA binding activity via the CK2 pathway, resulting in an increase of iNOS expression.     

绵羊肺泡巨噬细胞的分离培养和形态学观察

从绵羊肺组织中分离肺泡巨噬细胞进行原代培养,通过台盼蓝拒染试验和鸡红细胞吞噬试验检测肺泡巨噬细胞活力。利用电子显微镜对原代培养的巨噬细胞进行形态学观察。结果表明,本试验采用的方法适合分离培养绵羊肺泡巨噬细胞,活细胞数能达到90％以上。能为开展细胞病理学和细胞内寄生菌存活机理研究提供很好的试验材料。