自噬基因Beclin 1在SKOV3细胞中的表达及其调控相关信号传导途径的研究

目的探讨自噬基因Beclin 1在人卵巢癌SKOV3细胞中过表达后自噬相关信号调控通路PI3K/PKB途径中ClassⅠPI3K（p110α）、p-PKB和ClassⅢPI3K（hvps34）的表达变化以及对肿瘤细胞的自噬活性的影响.方法将自噬基因Beclin 1的真核表达载体pcDNA3.1/Beclin1转染SKOV3细胞;分别用荧光定量RT-PCR和Western blot在mRNA和蛋白水平检测用流式细胞仪检测Beclin1、p110α、hvps34和p-PKB的表达;在电镜和荧光显微镜下观察自噬现象,用流式细胞仪检肿瘤细胞自噬情况.结果 pcDNA3.1/Beclin1转染后SKOV3细胞Beclin1表达在mRNA和蛋白质水平明显高于转染空质粒pcDNA3.1和未转染细胞;PcDNA3.1/Beclin1转染后hvps34表达上调,而p110α、p-PKB的表达下调.PcDNA3.1/Beclin1转染SKOV3细胞后在在电镜下可见大量自噬囊泡形成.在荧光显微镜下见pcDNA3.1/Beclin1转染后SKOV3细胞中MDC阳性细胞明显增加.流式细胞仪检测pcDNA3.1/Beclin1转染后SKOV3细胞MDC平均荧光强度高于pcDNA3.1转染组和未转染组.Beclin 1在SKOV3中的过表达后抑制肿瘤细胞在体外的生长,抑制率为58.68%.结论自噬基因Beclin1在人卵巢癌细胞SKOV3中过表达可使ClassⅢPI3K（hvps34）表达上调,ClassⅠPI3K（p110α）及其下游的p-PKB表达下调,诱导肿瘤细胞自噬活性增加,抑制SKOV3在体外的增殖.     

miR-143通过负向调控Bcl-2抑制食管癌细胞的增殖

目的探讨miR-143通过负向调控B淋巴细胞瘤-2(Bcl-2)抑制食管癌细胞的增殖。方法 RTPCR法检测食管癌细胞TE-1、EC109、EC9706、KYSE150、KYSE510、SEG-1及人正常食管上皮细胞HEEC中miR-143表达,使用脂质体Lipofectamine~(TM) 2000将miR-143 mimics和miR-143 NC转入EC9706细胞中,48 h后,RT-PCR法检测miR-143表达,CCK-8法检测细胞活力,Ed U染色检测细胞增殖情况,流式细胞术检测细胞周期,RT-PCR及Western blot检测Bcl-2蛋白及mRNA的表达。结果 miR-143在食管癌细胞TE-1,EC109,EC9706,KYSE150,KYSE510及SEG-1中的表达量[(1.36±0.13),(1.08±0.10),(0.89±0.09),(0.95±0.09),(1.32±0.14),(0.96±0.11)]显著低于miR-143在人正常食管上皮细胞HEEC(2.38±0.15)中的表达量(P0.01)。与miR-143 NC组比较,miR-143 mimics组miR-143表达量显著升高(P0.01),细胞活力下降(P0.01),细胞增殖能力降低(P0.01),细胞周期阻滞在G1期(P0.01),同时Bcl-2蛋白及mRNA表达量显著降低(P0.01)。结论miR-143过表达能通过下调Bcl-2表达抑制EC9706细胞增殖。     

Duodenal-jejunal bypass surgery on type 2 diabetic rats reduces the expression of matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-1 in the thoracic aorta

Background Bariatric surgery offers a productive resolution of type 2 diabetes mellitus （T2DM）.The development of T2DM vasculopathy is due to chronic inflammation,which increases matrix metalloproteinase-9 （MMP-9） and tissue inhibitor of matrix metalloproteinase-1 （TIMP-1） expression.This study sought to examine MMP-9 and TIMP-1 expression in the thoracic aorta after duodenal-jejunal bypass （DJB） surgery on a T2DM rat model induced by a high-fat diet and low dose streptozotocin （STZ）.Methods Twenty-one T2DM Wistar rats induced by high-fat diet and low dose STZ were randomly divided into DJB and sham duodenal-jejunal bypass （S-DJB） groups.Ten Wistar rats were fed a normal diet as a control.Recovery of gastrointestinal function post-operation and resumption of a normal diet completed the experiment.Body weight,blood glucose,blood lipid levels,and MMP-9 and TIMP-1 expression levels in aortic endothelial cells were measured throughout.Results DJB rats showed significant weight loss 2 weeks post-operation compared with S-DJB rats.After surgery,DJB rats showed significant improvement and steady glycemic control with improved insulin sensitivity and glucose tolerance.They also exhibited improved lipid metabolism with a decrease in fasting free fatty acids （FFAs） and triglycerides （all P ＜0.05）.Immunohistochemistry showed decreased MMP-9 and TIMP-1 expression 12 weeks after surgery （P ＜ 0.01）.Conclusions DJB surgery on an induced T2DM rat model improves blood glucose levels and lipids,following a high-fat diet and low dose STZ treatment.In addition,DJB decreased MMP-9 and TIMP-1 expression in vascular endothelial cells,which may play an important role in delaying the development of T2DM vascular disease.     

Early changes of CD4+CD25+Foxp3+ regulatory T cells and Th1/Th2, Tc1/Tc2 profiles in the peripheral blood of rats with controlled hemorrhagic shock and no fluid resuscitation

Background  Hemorrhagic shock induces immune dysfunction. Regulatory T cells (Tregs), T-helper (Th) cells, and cytotoxic T-lymphocytes (CTLs) can execute many crucial actions in immune and inflammatory responses. This study was conducted to investigate the early pathophysiological changes of CD4⁺CD25⁺Foxp3⁺ Treg and Th1/Th2, Tc1/Tc2 profiles in the peripheral blood of rats with controlled hemorrhagic shock and no fluid resuscitation.

Methods  A rat model of controlled hemorrhagic shock with no fluid resuscitation was established. Peripheral blood samples were taken before and four hours after hemorrhagic shock with no fluid resuscitation. Three color flow cytometry was used to detect Tregs, Th1, Th2, Tc1 and Tc2 cells in the samples.

Results  In the peripheral blood of rats, the percentage of Tregs four hours after hemorrhagic shock was significantly lower than before hemorrhagic shock (P=0.001). The ratios of Th1/Th2 and Tc1/Tc2 were changed from (23.08±8.98)% to (23.91±15.36)%, and from (40.40±21.56)% to (65.48±23.88)%, respectively.

Conclusions  At an early stage, the advent of hemorrhagic shock is related to an early decrease of Tregs, and a mild shift in the Th1/Th2, Tc1/Tc2 balance toward Th1 and Tc1 dominance. These changes are part of a hyper-inflammatory state of the host, and will deteriorate the maintenance of immune balance. Further influences and detailed mechanisms need to be investigated.     

顺铂通过活性氧协同抗hDR5抗体诱导食管癌细胞凋亡

目的：探讨顺铂与抗死亡受体5（DR5）激动性抗体mDRA-6联合应用对食管癌细胞系EC9706细胞凋亡的影响及作用机制.方法：顺铂、抗体mDRA-6单独或联合作用于食管癌细胞,用流式细胞术检测药物的细胞毒作用、食管癌细胞表面DR5表达、细胞凋亡、细胞内活性氧水平、以及线粒体膜电位的变化;在荧光显微镜下观察细胞凋亡的形态学变化及DR5表达.结果：顺铂和抗体mDRA-6对食管癌细胞均具有细胞毒作用,并具有剂量依赖性,而且顺铂明显提高食管癌细胞对抗体mDRA-6细胞毒的敏感性.顺铂、抗体mDRA-6单独或联合应用均导致食管癌细胞呈现典型细胞凋亡特征.流式细胞术分析结果显示,mDRA-6和顺铂均诱导食管癌细胞凋亡,而且顺铂明显提高细胞对mDRA-6诱导细胞凋亡的敏感性;顺铂增强食管癌细胞表面及胞内的DR5表达,提高细胞内活性氧水平,降低线粒体膜电位.结论：顺铂主要通过活性氧激活细胞内线粒体细胞凋亡信号传导途径以及增强DR5表达,与抗体mDRA-6联合协同诱导食管癌细胞凋亡.研究结果对进一步探讨抗DR5激动性抗体及TRAIL的抗肿瘤临床应用有一定的指导意义.     

原发于泪囊淋巴瘤的影像和病理分析

Background Lymphoma of the lacrimal sac is rare,often misdiagnosed clinically.This study aimed to investigate the imaging features of these tumors and provide suggestions to aid the diagnosis.Methods In this retrospective study,five cases were assessed according to magnetic resonance imaging （MRI）,computed tomography （CT）,and pathological findings.All five patients underwent MRI and contrast-enhanced T1-weighted imaging （CE-T1WI）,of which four patients underwent dynamic contrast-enhanced （DCE） MRI and three patients underwent CT.Results Four cases and one case had a lymphoma in left and right medial canthus,respectively.Soft tissue surrounding the eyelids,subcutaneous tissue in the nasal dorsum,and involvement of the entire nasolacrimal canal were demonstrated in all five lesions.In two cases,the mass invaded the extraconal space.In one case,the mass invaded the adjacent medial rectus muscle and nasal area.Well-defined margins were observed in three cases and ill-defined margins in two cases.All cases showed homogeneous isointense lesions on T1Wl.Four cases showed homogeneous isointensity and one case demonstrated heterogeneous isointensity on T2Wl.After contrast injection,the lesion showed slight homogeneous isointensity and moderate enhancement in four cases and heterogeneous isointensity and moderate enhancement in one case.In the four patients who underwent DCE-MRI,a plateau pattern was revealed in three cases and washout pattern in one case.In the three cases who underwent CT,two cases had isointense and one case had hyperintense lesions.The lacrimal duct was remodeled and the surrounding bone compressed.Conclusions Tumors of the lacrimal sac showed homogeneous and isointense patterns on T1WI and T2WI with mildto-moderate enhancement and a plateau pattern on DCE-MRI.CT showed remodeling of the lacrimal duct with bone compression.     

Cigarette smoking increases levels of retinol-binding protein-4 in healthy men with normal glucose tolerance

Background  Smoking is related with insulin resistance and type 2 diabetes mellitus. Retinol-binding protein-4 is a new adipocytokine associated with insulin resistance. We investigated the serum levels of a series of adipocytokines including retinol-binding protein-4 in smokers and non-smokers to explore the possible roles of adipocytokines on smoking induced insulin resistance.

Methods  A total of 136 healthy male subjects (92 smokers and 44 non-smokers) with normal glucose tolerance were enrolled in the study. Adipocytokines including retinol-binding protein-4, visfatin, leptin, resistin, adiponectin were measured for the comparison between the two groups. Serum lipid profile, glucose, true insulin and proinsulin levels were measured as well in both groups. Food intake spectrum was also investigated.

Results  Both groups had similar profile of food consumption; visfatin, leptin, resistin and adiponectin, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, as well as blood pressure and body mass index, were similar in both groups. Triglycerides, retinol-binding protein-4 and homeostatic model assessment index for insulin resistance were higher in smoker group ((2.58±2.53) vs. (1.60±0.94) mmol/L, (26.05±8.50) vs. (21.83±8.40) µg/ml, and 2.25±2.08 vs. 1.58±1.15, respectively).

Conclusion  Smoking may have effect on insulin sensitivity, which is correlated with retinol-binding protein-4.

     

Prostate specific membrane antigen knockdown impairs the tumorigenicity of LNCaP prostate cancer cells by inhibiting the phosphatidylinositol 3-kinase/Akt signaling pathway

Background Prostate specific membrane antigen （PSMA） can facilitate the growth,migration,and invasion of the LNCaP prostate cancer cell lines,but the underlying molecular mechanisms have not yet been clearly defined.Here,we investigated whether PSMA serves as a novel regulator of the phosphatidylinositol 3-kinase （PI3K）/Akt signaling by employing PSMA knockdown model and PI3K pharmacological inhibitor （LY294002） in LNCaP prostate cancer cells.Methods PSMA knockdown had been stably established by transfecting with lentivirus-mediated siRNA in our previous study.Then,LNCaP cells were divided into interference,non-interference,and blank groups.We first testified the efficacy of PSMA knockdown in our LNCaP cell line.Then,we compared the expression of PSMA and total/activated Akt by Westem blotting in the above three groups with or without LY294002 treatment.Furthermore,immunocytochemistry was performed to confirm the changes of activated Akt （p-Akt,Ser473） in groups.Besides,cell proliferation,migration,and cell cycle were measured by CCK-8 assay,Transwell analysis,and Flow cytometry respectively.Results After PSMA knockdown,the level of p-Akt （Ser473） but not of total-Akt （Akt1/2） was significantly decreased when compared with the non-interference and blank groups.However,LY294002 administration significantly reduced the expression of p-Akt （Ser473） in all the three groups.The results of immunocytochemistry further confirmed that PSMA knockdown or LY294002 treatment was associated with p-Akt （Ser473） down-regulation.Decrease of cell proliferation,migration,and survival were also observed upon PSMA knockdown and LY294002 treatment.Conclusions Taken together,our results reveal that PI3K/Akt signaling pathway inhibition may serve as a novel molecular mechanism in LNCaP prostate cancer cells of PSMA knockdown and suggest that Akt （Ser473） may play a critical role as a downstream signaling target effector of PSMA in this cellular model.     

Rejection of insulin therapy among patients with type 2 diabetes in China: reasons and recommendations

Background Insulin injection therapy is one of the most effective treatments for type 2 diabetes meUitus （T2DM）. Many people with T2DM in western countries resist starting insulin therapy; whether the same is true in China is unknown. This survey-based study assessed acceptance and rejection of insulin therapy among individuals with T2DM in China and self- reported reasons for these therapy choices. It also examined what methods may be useful for increasing the rate of insulin acceptance. Methods A multi-center, cross-sectional survey was conducted between April and July 2010 to a convenience sample of inpatients and outpatients at 50 medical centers across 29 administrative divisions in China. Data were collected on sociodemographic and T2DM characteristics, therapy regime, and attitudes toward insulin therapy. Results A total of 6 043 patients were surveyed, and 5 961 complete questionnaires （98.6%） were used in the analysis. Just over half the respondents （3 460, 58.0%） reported negative attitudes to insulin therapy, including 2 508 of the 4 469 patients （56.1%） whose physicians had recommended it to them. Of the patients counseled to use insulin, 800 （17.9%） were unwilling to start therapy and cited the following reasons： inconvenience （64.3%）; concerns over addiction （24.6%）; pain （14.3%）; side effects （14.1%）; and high cost （13.6%）. Logistic regression suggested that respondents would be more willing to undertake insulin therapy if they had received diabetes education, had positive attitudes to the treatment, had higher glycosylated hemoglobin level, or had suffered diabetes for a longer period or with more complications. Conclusions Patients with T2DM in China are often resistant to insulin therapy if they have been diagnosed with the disease for a relatively short time or if the disease has been relatively mild. Educating patients on the benefits of insulin therapy, not only at the initial diagnosis with T2DM but also when insulin therapy becomes necessary, will l     

Mammalian target of rapamycin inhibitor abrogates abnormal osteoclastogenesis in neurofibromatosis type 1

Background Neurofibromatosis type 1 (NF1) is the most common genetic syndrome predisposing patients to various tumors due to dysregulation of the Ras signaling pathway.Recent research has shown NF1 pat...     

体外hEGF对食管癌EC9706细胞增殖影响的研究

目的:研究人表皮生长因子(hEGF)对食管癌EC9706细胞增殖的影响作用,探讨hEGF不同浓度、不同时间对食管癌细胞生长的影响。方法:体外正常条件培养EC9706食管鳞癌细胞株,无血清饥饿细胞,加入hEGF,通过镜下形态观察、MTT染色、流式细胞技术等观察细胞增殖变化情况。结果:hEGF在200ng/ml浓度、24h作用时间点,对EC9706细胞有明显刺激增殖作用;倒置显微镜下观察,hEGF刺激细胞呈长梭形改变,细胞连接紧密;细胞周期分析,hEGF刺激细胞30.03%处于增殖活跃的S期,较之对照组15.52%,有极显著性差异。结论:hEGF能够刺激食管癌EC9706细胞增殖,其对细胞增殖的刺激作用呈量效、时效关系。     

Role of microRNA-181a in the apoptosis of tubular epithelial cell induced by cisplatin 

Background  Cisplatin (DDP) is one of most effective and most commonly used therapeutic agent in treating tumors, it can accumulate in the kidney and lead to acute renal failure. MicroRNA-181a can induce cell apoptosis by suppressing the expression of Bcl-2 family. In the present study, we investigated the role of microRNA-181a in the apoptosis of tubular epithelial cell induced by DDP.

Methods  HK-2 cells were cultured, transfected with microRNA-181a inhibitor for 48 hours, and stimulated with 50 µmol/L cisplatin for 24 hours. MicroRNA-181a expression was analyzed by real time PCR, and cell apoptosis was detected by flow cytometry. Moreover, Bcl-2 and Bcl-2-associated X protein (Bax) expression were measured by Western blotting.

Results  MicroRNA-181a expression significantly down-regulated in cells transfected with microRNA-181a inhibitor, compared with that in untransfectd cells (21.19±2.01 vs. 38.87±1.97, P <0.05). Cell apoptosis induced by DDP significantly decreased in cells transfected with MicroRNA-181a inhibitor. Compared with DDP treated cells alone, Bcl-2 expression strikingly was up-regulated and Bax expression was down-regulated in cells transfected with microRNA-181a inhibitor.

Conclusion  One pathway of DDP induces apoptosis of tubular epithelial cell by suppressing Bcl-2 expression is achieved by regulating the target gene of MicroRNA-181a.

     

miR-1通过PI3K/Akt/mTOR信号通路对高糖诱导的H9c2心肌细胞自噬的影响

目的 探讨miR-1对高糖诱导的H9c2心肌细胞自噬及磷脂酰肌醇3-激酶（PI3K）/蛋白激酶B（Akt）/哺乳动物雷帕霉素靶蛋白（mTOR）信号通路的影响。方法H9c2细胞随机分为4组。正常组使用普通培养基培养,未转染;诱导组使用含33 mmol/L葡萄糖的培养基诱导,未转染;miR-1 NC组使用含33 mmol/L葡萄糖的培养基诱导,转染miR-1 NC;miR-1 inhibitor组使用含33 mmol/L葡萄糖的培养基诱导,转染miR-1 inhibitor。在加入葡萄糖诱导前48 h,使用Lipofectamine 3000转染试剂盒进行转染。实时荧光定量聚合酶链式反应（qRT-PCR）检测H9c2细胞和高糖诱导的H9c2细胞中miR-1表达水平;CCK-8法检测各组H9c2细胞增殖活性;蛋白免疫印记法（Western blot）检测各组H9c2细胞中Beclin1、p65、PI3K蛋白表达水平、LC3-Ⅱ/LC3-Ⅰ比值以及AKT、mTOR蛋白磷酸化水平;生物信息学预测和双萤光素酶验证miR-1和PI3K的靶向关系。结果与正常组相比,诱导组的H9c2细胞中,miR-1表达水平显著升高（P<0.05）,PI3K蛋白表达水平显著降低（P<0.05）。与正常组相比,诱导组H9c2细胞Beclin1蛋白表达、LC3-Ⅱ/LC3-Ⅰ比值显著升高,自噬小体增多,细胞增殖率、p62蛋白表达以及PI3K、Akt、mTOR蛋白磷酸化水平显著降低（P<0.05）;与诱导组和miR-1 NC组相比,miR-1 inhibitor组H9c2细胞miR-1水平、Beclin1蛋白表达、LC3-Ⅱ/LC3-Ⅰ比值显著降低,自噬小体减少,细胞增殖率、p62蛋白表达以及PI3K、Akt、mTOR蛋白磷酸化水平显著升高（P<0.05）;miR-1和PI3K间存在靶向关系。结论在高糖诱导的H9c2细胞中,miR-1表达水平升高,抑制miR-1,可通过靶向激活PI3K/Akt/mTOR信号通路,抑制高糖诱导的H9c2心肌细胞自噬。     

A novel and feasible way to cultivate and purify endothelial progenitor cells from bone marrow of children with congenital heart diseases

Background  Endothelial progenitor cells (EPCs) are used in vascular tissue engineering and clinic therapy. Some investigators get EPCs from the peripheral blood for clinic treatment, but the number of EPCs is seldom enough. We have developed the cultivation and purification of EPCs from the bone marrow of children with congenital heart disease, to provide enough seed cells for a small calibre vascular tissue engineering study.

Methods  The 0.5-ml of bone marrow was separated from the sternum bone, and 5-ml of peripheral blood was collected from children with congenital heart diseases who had undergone open thoracic surgery. CD34+ and CD34+/VEGFR+ cells in the bone marrow and peripheral blood were quantified by flow cytometry. CD34+/VEGFR+ cells were defined as EPCs. Mononuclear cells in the bone marrow were isolated by Ficoll^® density gradient centrifugation and cultured by the EndoCult Liquid Medium Kit™. Colony forming endothelial cells was detected. Immunohistochemistry staining for Dil-ac-LDL and FITC-UEA-1 confirmed the endothelial lineage of these cells.

Results  CD34+ and CD34+/VEGFR+ cells in peripheral blood were (0.07±0.05)% and (0.05±0.02)%, respectively. The number of CD34+ and CD34+/VEGFR+ cells in bone marrow were significantly higher than in blood, (4.41±1.47)% and (0.98±0.65)%, respectively (P <0.0001). Many colony forming units formed in the culture. These cells also expressed high levels of Dil-ac-LDL and FITC-UEA-1.

Conclusion  This is a novel and feasible approach that can cultivate and purify EPCs from the bone marrow of children with congenital heart disease, and provide seed cells for small calibre vascular tissue engineering.

     

LRP16 gene protects mouse insulinoma MIN6 cells against fatty acid-induced apoptosis through Akt/FoxO1 signaling

Background  Pancreatic b cells are susceptible to fatty acid-induced apoptosis. The 17b-estradiol (E2) protects pancreatic b cells from apoptosis, mediated by the estrogen receptor-a (ERa). The mRNA level and promoter activity of leukemia-related protein (LRP) 16 were significantly increased by E2 in ER-a and LRP16 was a co-activator of ER-a. The aim of the study was to assess the effects of LRP16 on fatty acid-induced apoptosis in MIN6 cells.

Methods  Cells with over-expressing LRP16 were obtained by lipidosome transfection. Insulin content and glucose-stimulated insulin secretion (GSIS) were examined by radioimmunoassay. Western blotting was applied to detect protein expression. Apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry. The forkhead boxO1 (FoxO1) subcellular localization was determined by immunocytochemical analysis.

Results  MIN6-LRP16 cells with overexpression of LRP16 were successfully established, and protein expression of LRP16 was 2.29-fold of that of control cells (MIN6-3.1, P <0.05). Insulin content and GSIS in MIN6-LRP16 were substantially increased compared with those in control cells. When cells were stimulated with glucose, increased phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and serine-threonine kinase (Akt) were observed in MIN6-LRP16. When cells were under palmitate pressure, the TUNEL-positive rate in MIN6-LRP16 was (17.0±0.5)%, while it in MIN6-3.1 was (22.0±0.4)%. In palmitate-treated cells, attenuated Akt phosphorylation was observed, but the attenuation in Akt activity was partially restored in MIN6-LRP16 cells. Meanwhile, nuclear localization of FoxO1 in MIN6-LRP16 was apparently reduced compared with that in control cells.

Conclusions  LRP16 regulated insulin content and GSIS in MIN6 cells by ERK1/2 and Akt activated way. Meanwhile, LRP16 overexpression protected MIN6 cells from fatty acid-induced apoptosis by partially restoring Akt phosphorylation and inhibiting FoxO1 nuclear redistribution. Therefore, LRP16 played important roles not only in insulin content and GSIS but also in the antilipotoxic effect mediated by Akt /FoxO1 signaling.

     

RNA干扰沉默乏氧诱导因子1α对乏氧条件下食管鳞癌细胞化疗敏感性的影响

目的探讨RNA干扰技术沉默乏氧诱导因子（HIF）-1α对食管鳞癌EC9706细胞乏氧条件下化疗敏感性的影响及其机制。方法应用化学乏氧法[氯化钴（CoCl2）加入培养液的终浓度为75μmol／L]体外模拟肿瘤乏氧微环境。采用MTS比色法检测常氧培养组和乏氧培养组EC9706细胞在顺铂／紫杉醇作用下细胞的抑制率,以及RNA干扰后乏氧培养细胞在顺铂／紫杉醇作用下细胞的抑制率。应用Western印迹方法检测HIF-1α基因沉默后乏氧诱导HIF-1α蛋白表达变化。用流式细胞仪检测RNA干扰前后乏氧条件下EC9706细胞的细胞周期。结果针对HIF-1α基因的siRNA干扰技术,有效抑制乏氧诱导的HIF-1α蛋白表达。同一药物浓度常氧培养组细胞抑制率均明显高于乏氧培养组（均P〈0．05）。相同药物浓度及相同的乏氧条件下RNA干扰组抑制率均明显高于未转染组及转染control siRNA组（均P〈0.05）。相同的乏氧条件下转染HIF-1α siRNA与未转染组／转染无关对照siRNA组相比,S期显著增加（P〈0．05）、G1期细胞减少（P〈0．05）。结论乏氧条件下HIF-1α诱导EC9706细胞周期停止,可能是乏氧条件下细胞耐药的机制之一。RNA干扰可逆转食管癌细胞EC9706乏氧环境中化疗耐药。     

RNA干扰对EC9706细胞mTOR表达及细胞生长与凋亡的影响

目的:探讨RNA干扰技术对人食管癌EC9706细胞哺乳动物雷帕霉素靶蛋白(mTOR)的表达及细胞生长与凋亡的影响.方法:设计合成mTOR siRNA,采用低、中、高浓度(50、100与150 nmoL/L)的mTOR siRNA分别转染EC9706细胞24、48与72 h.同时设无义对照组(转染无义对照siRNA)、空白对照组(转染空脂质体)及正常对照组(不转染).采用免疫细胞化学与原位杂交法分别检测各组EC9706细胞中mTOR蛋白与mRNA的表达;应用MTT法检测细胞增殖,计算细胞生长抑制率;应用TUNEL法检测转染24 h时细胞凋亡,计算凋亡指数(AI).结果:转染24、48与72 h,6组细胞mTOR蛋白和mRNA的表达差异均有统计学意义(mTOR蛋白:F=24.14,45.78,59.19,P均＜0.001;mTOR mRNA:F=41.42,69.74,43.71,P均＜0.001),细胞生长抑制率差异亦有统计学意义(F=143.85,172.98,155.01,P均＜0.001);低、中、高浓度组转染不同时间点间比较,mTOR蛋白(F=42.23,29.46,50.22,P均＜0.001)、mTOR mRNA(F=6.48,8.50,4.80,P均＜0.05)及细胞生长抑制率(F=78.77,76.14,52.28,P均＜0.001)差异均有统计学意义.mTOR siRNA转染组EC9706细胞mTOR蛋白与mRNA的表达均低于各对照组,且mTOR蛋白及mRNA的表达随mTOR siRNA浓度的增加及转染时间的延长而减弱(P＜0.05).不同浓度mTOR siRNA转染组EC9706细胞生长抑制率均高于各对照组,且细胞生长抑制率随mTOR siRNA浓度的增加和转染时间的延长而升高(P＜0.05).转染24 h,6组细胞AI相比,差异有统计学意义(F=442.96,P＜0.001),mTOR siRNA转染组AI均高于各对照组,且高浓度转染组AI高(P＜0.05).结论:mTOR siRNA可有效抑制EC9706细胞mTOR蛋白与mRNA的表达,且能抑制EC9706细胞的增殖并促进其凋亡.     

A preliminary study of imaging paclitaxel-induced tumor apoptosis with 99Tcm-His10-Annexin V

Backgroud In tumors the process of apoptosis occurs over an interval of time after chemotherapy. It is important to determine the best time for detecting apoptosis by in vivo imaging. In this study, we evaluated the dynamics and feasibility of imaging non-small cell lung cancer (NSCLC) apoptosis induced by paclitaxel treatment using a 99Tcm-labeled Annexin V recombinant with ten consecutive histidines (His10-Annexin V) in a mouse model.

Methods 99Tcm-His10-Annexin V was prepared by one step direct labeling; radio-chemical purity (RCP) and radio-stability was tested. The binding of 99Tcm-His10-Annexin V to apoptotic cells was validated in vitro using camptothecin-induced Jurkat cells. In vivo bio-distribution was determined in mice by dissection. The human H460 NSCLC tumor cell line (H460) tumor-bearing mice were treated with intravenous paclitaxel 24, 48 and 72 hours later. 99Tcm-His10-Annexin V was injected intravenously, and planar images were acquired at 2, 4 and 6 hours post-injection on a dual-head gamma camera fitted with a pinhole collimator. Tumor-to-normal tissue ratios (T/NT) were calculated by ROI analysis and they reflected specific binding of 99Tcm-His10-Annexin V. Mice were sacrificed after imaging. Caspase-3, as the apoptosis detector, was determined by flow cytometry, and DNA fragmentation was analyzed by the terminal deoxynucleotidytransferase mediated dUTP nick-end labeling (TUNEL) assay. Nonspecific accumulation of protein was estimated using bovine serum albumin (BSA). The imaging data were correlated with TUNEL-positive nuclei and caspase-3 activity.

Results 99Tcm-His10-Annexin V had a RCP >98% and high stability 2 hours after radio-labeling, and it could bind to apoptotic cells with high affinity. Bio-distribution of 99Tcm-His10-Annexin V showed predominant uptake in kidney, relatively low uptake in myocardium, liver and gastrointestinal tract, and rapid clearance from blood and kidney was observed. The T/NT was significantly increased after paclitaxel treatment, whereas it was low in untreated tumors (T/NT=1.43±0.18). The %ID/g activity in Group 2 (24 hours), Group 3 (48 hours) and Group 4 (72 hours) after treatment was 2.55±0.73, 3.35±1.10, and 3.4±0.96, respectively. Whereas in the non-treated group, Group 1, %ID/g was 1.10±0.18. The radiotracer uptake was positively correlated to the apoptotic index (r=0.852, P<0.01), as well as caspase-3 activity (r=0.816, P<0.01).

Conclusion This study addresses the dynamics and feasibility of imaging non-small cell lung tumor apoptosis using 99Tcm-His10-Annexin V.

     

Anatomical references for tibial sagittal alignment in total knee arthroplasty: A comparison of three anatomical axes based on 3D reconstructed CT images

Background This study was designed to analyze three tibial axis reference lines including the anterior tibial cortex （ATC） line, the fibular line （FL）, and the anatomical axis of tibia （AAT） line, to determine which line most closely parallels the mechanical axis （MA） of the tibia in the sagittal plane. The clinical relevance of the study is that through finding a reliable landmark on the leg, a surgeon may minimize posterior tibial slope measurement errors thereby and improving the technique for assuring proper alignment of total knee arthroplasty.