放射诱导调控序列的合成及其辐射诱导特性的研究

目的　合成放射诱导调控序列并鉴定其辐射诱导特性。方法　利用人工寡核苷酸片段合成含有 6个重复CArG元件的放射诱导调控序列 ,以绿色荧光蛋白 (GFP)作为报告基因转染Tca8113细胞检测其辐射诱导特性。结果　低剂量放射线照射可诱导这种人工调控序列增强GFP在Tca8113细胞中的表达 ,且 3Gy剂量最为明显 ,提高到放射前的 16 1%。结论　人工合成放射诱导调控序列在低剂量放射线照射下能明显增强其下游外源性基因的表达 ,为进一步研究放射 -基因治疗奠定了基础。     

Multidrug resistance-associated protein 3 confers resistance to chemoradiotherapy for rectal cancer by regulating reactive oxygen species and caspase-3-dependent apoptotic pathway

This study aimed to clarify the role of multidrug resistance-associated protein 3 (MRP3) in resistance to neoadjuvant chemoradiotherapy and long-term prognosis of advanced rectal cancer. Immunohistochemistry was used to measure MRP3 expression in biopsy specimens of 144 stage II–III rectal cancer patients who received preoperative chemoradiotherapy. The effect of MRP3 expression on short-term pathological response and postoperative long-term prognosis were assessed using the Cox proportional hazards model. Short interfering RNAs targeting MRP3 were synthesized and used to transfect human colorectal carcinoma cell lines. The effect of MRP3 down-regulation on cell proliferation and apoptosis in response to 5-fluorouracil and/or irradiation were examined in vitro and in xenograft mouse models, respectively. The content of intracellular reactive oxygen species and the activity of caspase-3-dependent apoptotic pathway in response to irradiation were further evaluated. High expression (immunoreactive score > 6) of MRP3 significantly predicted poor pathological response to chemoradiotherapy (tumor regression grade ≤ 2 vs. ≥3, p = 0.002) in univariate analysis and unfavorable long-term prognosis (5-year overall survival: HR = 1.612, 95% CI, 1.094–2.375, p = 0.016; 5-year disease-free survival: HR = 1.513, 95% CI, 1.041–2.200, p = 0.030) in multivariate Cox analysis. MRP3 down-regulation significantly increased 5-fluorouracil or irradiation-induced cell apoptosis and attenuated tumor growth following irradiation in animal models. MRP3 inhibition significantly reduced intracellular reactive oxygen species exporting from cells following irradiation, and increased expression of cleaved poly ADP-ribose polymerase and caspase-3. Aberrant expression of MRP3 in rectal cancer confers chemo-radioresistance. MRP3 might be a predictive factor and an attractive target in treating advanced rectal cancer.     

RFT2 is overexpressed in esophageal squamous cell carcinoma and promotes tumorigenesis by sustaining cell proliferation and protecting against cell death

Human riboflavin transporter 2 (RFT2, also termed as SLC52A3) was recently identified as a susceptibility gene to esophageal squamous cell carcinoma (ESCC), however, its expression and biologic function has remained unclear in ESCC. In this study, we demonstrated that RFT2 was frequently overexpressed in tumor samples compared with normal adjacent tissue in ESCC patients. Knockdown of RFT2 in ESCC cells resulted in decreases of intracellular flavin status, mitochondrial membrane potential and cellular ATP levels, and inhibitions of cell proliferation, colony formation and anchorage-independent growth. Knockdown of RFT2 increased p21 and p27 protein levels, decreased their downstream targets cyclin E1 and Cdk2 protein levels and caused pRb hypophosphorylation, leading to cell cycle arrest at G1-G1/S. Knockdown of RFT2 also reduced anti-apoptotic proteins Bcl-2, Bcl-xl and survivin levels, caused activation of caspase-3 and apoptosis. In contrast, ectopic overexpression of RFT2 in ESCC cells promoted cell proliferation under restricted conditions (soft agar), conferred resistance to cisplatin, and enhanced tumorigenicity in nude mice. These results suggest that RFT2 contributes to ESCC tumorigenesis and may serve as a potential therapeutic target.     

TCR dynamics on the surface of living T cells.

T lymphocyte activation by specific antigen requires prolonged TCR occupancy and sustained signaling. This is accomplished by the formation of a specialized signaling domain, the immunological synapse, at the T cell-antigen-presenting cell contact site. Surface receptors and signaling components are progressively recruited into this domain where they are organized in defined three-dimensional structures. To better understand how TCR are supplied to the signaling domain during the activation process, we measured (using confocal microscopy and photo-bleaching recovery techniques) lateral mobility of GFP-tagged TCR on living Jurkat cell surface. We show that: (i) surface-expressed TCR exhibit an intrinsic, actin cytoskeleton-independent, lateral mobility which allows them to passively diffuse over the entire T cell surface within approximately 60 min and (ii) non-stimulated TCR rapidly enter the signaling domain. Our results indicate that TCR lateral mobility per se is sufficient to ensure TCR supply to the immunological synapse in the course of sustained T cell activation.     

GFP标记干细胞修复椎间盘退变中的示踪研究

目的探讨绿色荧光蛋白(GFP)示踪时效及GFP标记的骨髓间充质干细胞(MSCs)在移植后参与退变修复过程中的细胞增殖情况。方法使用针吸髓核法建立兔的椎间盘退变模型,体外培养MSCs,并用含有绿色荧光蛋白标记的腺病毒载体(Adeno-XTM-GFP)转染,成为GFP标记的MSCs(GFP-MSCs),于造模2周后植入造模的椎间盘内。在移植后第2、4、6、8周用激光共聚焦显微成像技术,观察MSCs的增殖情况,对比GFP本身荧光和免疫荧光的示踪时间。结果非免疫荧光组GFP本身荧光强度能够持续到4周,后较微弱甚至难以辨别;免疫荧光组用FITC荧光二抗标记的GFP-MSCs在8周内都能够持续稳定的显现荧光,4个时间点GFP-MSCs的阳性率的可信区间分别是:2周(14.64±2.05)%;4周(21.85±2.45)%;6周(31.03±4.03)%;8周(36.37±4.42)%。结论GFP-MSCs在椎间盘微环境中能够稳定增殖。若示踪研究需要持续超过4周,则应对GFP行免疫荧光染色,可以使有效示踪时间持续至少8周。     

HBV启动子调控的GFP在肿瘤细胞中的表达

为进一步探讨针对晚期肺癌患者治疗的新方式 ,本文根据曾有动物实验研究报告 (即ＢＣＧ辅以ＩＬ 2吸入防治实验肺癌模型 ) ,通过采用超声雾化方式 ,在临床上试行将相关免疫制剂配合化疗药物以气溶胶微粒形式吸入肺组织用以治疗肺癌 ,先后对 10例患者进行共 16例次的治疗。初步观察该方法在控制肿瘤病灶发展、减轻病痛等方面临床意义 ,现报告如下。10例患者中 ,男 7例 ,女 3例 ;年龄 6 2～ 88岁。所有患者均以临床表现 ,影像学检查 ,部分经病理证实诊断为肺癌 ,其中 ,原发性肺癌 7例 (腺癌、鳞癌各 3例 ,1例无病理 ) ;转移性肺癌 3例。ＫＰＳ…     

Ad-vcam-1-gfp重组腺病毒转染人脐血源基质细胞的实验研究

本研究探讨血管细胞黏附分子（vcam-1）修饰的人脐血源基质细胞（human umbilical cord blood derived strom cells，CBDSC）在造血调控中的作用。采用DNA重组技术，将目的基因vcam-1克隆至含有报告基因gfp的穿梭质粒；在BJ5183细胞中与pAdeasy—1质粒进行同源重组，产生重组腺病毒载体转染人脐血源基质细胞并进行鉴定。结果表明：vcam-1基因与pAdTrack—CMV载体成功连接，经NotⅠ／XhoⅠ双酶切后电泳可见2个大小约为9kb和2kb左右条带，经PCR法扩增后电泳可见1个600bp左右条带，证明pAdTrack—CMV—vcam-1重组质粒构建成功。pAdTrack—CMV—vcam-1质粒与pAdeasy—1质粒同源重组后，产物经PACⅠ酶切后电泳可观察到2个大小约为31kb、4kb左右条带，与预期结果相符。腺病毒载体转染人脐血源基质细胞后免疫化学、RT—PCR、荧光显微镜等方法均检测到目的基因vcam-1的表达。结论：构建ad—vcam-1-gfP重组腺病毒载体可成功转染人脐血源基质细胞并使其vcam-1表达增高。     

CD2AP真核表达载体的构建及在COS-7细胞中的表达定位

目的:构建pEGFP-CD2AP真核表达载体,检测其在COS-7细胞中的表达.方法:PCR扩增CD2相关蛋白(CD2-associated protein,CD2AP)全长编码序列,PCR产物连接入pGEM T-Easy载体,经测序确认无误后,亚克隆入pEGFP-C2构建pEGFP-CD2AP真核表达载体,采用Lipofectamine 2000转染COS-7细胞,荧光显微镜检测报告基因表达产物EGFP.结果:pEGFP-CD2AP表达载体转染COS-7细胞后,可在细胞内观察到报告基因和目的基因的表达产物.结论:pEGFP-CD2AP真核表达载体构建成功,并可在细胞内表达,这将为今后的CD2AP功能研究奠定基础.     

Lifespan extension by n-butanol extract from seed of Platycladus orientalis in Caenorhabditis elegans

Aim of the study

As a traditional Chinese medicine, seed of Platycladus orientalis(Linnaeus) Franco has been extensively used as a tonic and sedative remedy. The present study was conducted to investigate whether lifespan was extended and the mechanisms of n-butanol extract from seed of Platycladus orientalis (BSPO) in Caenorhabditis elegans. The findings could provide the pharmacological basis for a treatment in traditional medicine.

Materials and methods

Lifespan extension by BSPO was evaluated under normal culture conditions and in a stress test. A possible mechanism of the anti-aging effect of BSPO, a change in the stress-resistance of related proteins, was also investigated in C. elegans.

Results

It has been shown that BSPO could significantly extend lifespan of C. elegans in a concentration dependent manner under normal culture conditions and stress. Further studies demonstrated that BSPO treatment significantly decreased reactive oxygen species (ROS) accumulation, up-regulated resistance to stress of related proteins, including glutathione S-transferase-4 (GST-4) and heat shock protein-16.2 (HSP-16.2), and reduced the amount of lipofuscin in transgenic C. elegans.

Conclusion

These results indicated that BSPO extended the lifespan, which could be attributed to its direct ROS scavenging activity, reducing the amount of lipofuscin and increasing the expression of gens associated with resistance to stress. These obtained data provided valuable support for traditional clinical practice to extend lifespan and to provide tonic remedy.