p53在神经酰胺诱导内皮细胞凋亡中的作用

目的:探讨p53在外源性神经酰胺(C2-ceramide)诱导人脐静脉内皮细胞凋亡中的作用。方法:体外培养脐静脉内皮细胞,用不同浓度的C2-ceramide进行处理,Tunel检测细胞凋亡;逆转录-聚合酶链反应(RT-PCR)和Western blot检测p53的表达;并用p53的抑制剂PFT-α(pifithrin alpha,PFT-α)预处理细胞,再加入C2-ceramide与对照组比较观察细胞凋亡指数。结果:C2-ceramide呈剂量依赖性诱导内皮细胞凋亡;p53的表达随着C2-ceramide浓度的增加呈现降低的趋势;PFT-α不能抑制C2-ceramide诱导的凋亡。结论:神经酰胺能诱导内皮细胞的凋亡,可能不依赖于p53途径。     

PTEN在HepG2细胞中诱导凋亡发生及上调p53表达

目的 研究肿瘤抑制基因PTEN对HepG2细胞凋亡及p53蛋白表达的影响,并探讨相关机制。方法 将携带有野生型PTEN基因及突变型G129E-PTEN,C124A-PTEN基因的真核表达载体转染HepG2细胞,利用western印迹杂交检测PTEN表达、蛋白激酶B(PKB/Akt)和焦点粘附激酶(FAK)的磷酸化状态,以及野生型p53蛋白表达水平的变化,并应用流式细胞仪,激光共聚焦技术检测细胞周期及细胞凋亡情况。结果 与对照细胞相比,转染野生型PTEN和G129E-PTEN的HepG2细胞中磷酸化FAK(-65％,-65％)与磷酸化Akt(-93％,-35％)表达均存在不同程度的下调,而细胞凋亡率分别增加至19.8％±1.2％和9.2％±0.6％,并且p53蛋白表达上调( 120%,, 50％);然而转染C124A-PTEN的细胞中各项检测指标均无明显变化。 结论 PTEN依赖其蛋白磷酸酶活性抑制FAK的磷酸化;并主要通过脂质磷酸酶活性抑制Akt的磷酸化,并诱导HepG2细胞凋亡和p53蛋白表达上调。     

人原发性肝癌细胞株受照射后凋亡与癌基因表达

目的 探讨人原发性肝癌细胞株受照射后凋亡与ｂｃｌ－２、ｐ５３基因表达产物关系。方法 选择人原发性肝癌细胞株ＱＧＹ,１８０ＫＶＸ线照射,流式细胞仪技术定量测定凋亡发生率,单克隆抗体免疫化法测定受照射后ｂｃｌ－２、ｐ５３表达产物,Ｓｏｎｙ Ｍｉａｓ－３００ Ｓｐａｔｏ图象分析仪分析结果。结果 ＱＧＹ－７７３０细胞株自发凋亡率为４．７９％,随照射后时间延长及照射剂量增加凋亡发生率增加。Ｂｃｌ－１、ｐ５３     

Early apoptosis and cell death induced by ATX-S10Na ( Ⅱ)-mediated photodynamic therapy are Bax- and p53-dependent in human colon cancer cells

AIM: To investigate the roles of Bax and p53 proteins in photosensitivity of human colon cancer cells by using lysosome-localizing photosensitizer, ATX-S10Na (Ⅱ).METHODS: HCT116 human colon cancer cells and Bax-null or p53-null isogenic derivatives were irradiated with a diode laser. Early apoptosis and cell death in response to photodynamic therapy were determined by MTT assays, annexin V assays, transmission electron microscopy assays, caspase assays and western blotting.RESULTS: Induction of early apoptosis and cell death was Bax- and p53-dependent. Bax and p53 were required for caspase-dependent apoptosis. The levels of anti-apoptotic Bcl-2 family proteins, Bcl-2 and Bcl-XL,were decreased in Bax- and p53-independent manner.CONCLUSION: Our results indicate that early apoptosis and cell death of human colon cancer cells induced by photodynamic therapy with lysosome-localizingphotosensitizer ATX-S10Na (Ⅱ) are mediated by p53-Bax network and Iow levels of Bcl-2 and Bcl-XL proteins.Our results might help in formulating new therapeutic approaches in photedynamic therapy.     

老年急性心肌梗死猝死者心肌细胞凋亡与p53和Bcl—2蛋白表达的相关性研究

目的探讨p53和Bcl-2蛋白在老年急性心肌梗死(AMI)猝死者心肌细胞凋亡中的作用.方法用TUNEL法检测15例猝死者和10例心脏正常的车祸死亡者的心肌细胞凋亡,用免疫组化法检测p53和Bcl-2蛋白在心肌中的表达水平,并探讨它们之间的相互关系.结果 TUNEL法发现,猝死者梗死区的心肌细胞凋亡千分数老年组(663.00±117.12‰)明显高于正常对照(34.30±20.68‰)(P=0.00);p53蛋白表达阳性千分率(462.12±237.58‰)明显高于正常对照者(39.45±24.67‰)(P=0.000),且与梗死区心肌细胞凋亡数成明显的正相关性(r为0.701,P＜0.005);Bcl-2蛋白表达阳性率(40.83±31.29‰)明显低于正常对照(120.76±66.67‰)(P=0.0037),且与梗死区心肌细胞凋亡数成明显的负相关性(r为-0.840,P＜0.001);梗死区心肌细胞内p53和Bcl-2蛋白表达数之间呈明显的负相关性(r=-0.829,P＜0.001).结论 AMI猝死者梗死区心肌细胞存在明显的凋亡现象,且受p53蛋白上调、Bcl-2蛋白下调,两者相反调节其凋亡.     

玉米苞叶对动脉粥样硬化家兔平滑肌细胞凋亡及p53和Fas蛋白表达的影响

目的：探讨玉米苞叶防治动脉粥样硬化（AS）的机制。方法：选用大耳白家兔，复制家兔AS模型，随机分为动脉粥样硬化模型组，玉米苞叶组和正常对照组，成模后给予玉米苞叶煎剂治疗，8w后处死家兔，采用流氏细胞术检测平滑肌细胞的凋亡率以及凋亡相关基因p53和Fas蛋白表达。结果：模型组血管平滑肌细胞的凋亡率明显高于对照组（P＜0．05），p53和Fas蛋白的表达增强（P＜0．05），主动脉壁肉眼观测出现典型斑块。玉米苞叶组平滑肌细胞的凋亡率明显低于模型组（P＜0．05），p53和Fas蛋白表达下调（P＜0．05）；主动脉斑块面积较模型组明显减小，结论：玉米苞叶通过调节p53和Fas蛋白表达而调节AS家兔平滑肌细胞凋亡。     

p53基因在亚砷酸钠致人胚胎肺成纤维细胞凋亡中的作用

目的 探讨p53、Bax、bcl-2基因在亚砷酸钠(NaAs02)致人胚胎肺成纤维细胞(HELF)凋亡中的作用.方法 分别取转染了p53质粒HELF细胞(p53组)、转染了PC质粒的HELF细胞(PC组)、常规培养的HELF细胞(正常组),在6孔板中培养48 h后,分别加入0、3、9、15 mmoL/L NaAsO2溶液,培养24 h后,用real-time PCR法检测p53、Bax、bcl-2 mRNA基因表达水平,采用免疫组织化学SABC法检测p53、Bax、bcl-2基因蛋白表达水平;用流式细胞仪检测细胞凋亡情况.结果 p53组细胞p53基因mRNA表达水平(0.51±0.29)低于PC组及正常组[(1.32±0.26),(1.00±0.20),P均<0.05],p53组p53基因蛋白表达水平[(4.10±1.20)%]低于PC组和正常组[(8.00±1.63)%、(7.90±1.79)%,P均<0.05];p53组、PC组、正常组在染砷0、3、9、15 mmol/L时,细胞凋亡率[(0.57±0.28)%、(22.91±4.86)%、(40.05±3.93)%、(44.87±3.58)%,(0.65±0.24)%、(14.09±3.49)%、(20.31±3.66)%、(32.42±3.63)%,(0.56±0.25)%、(12.14±3.70)%、(19.61±3.63)%、(30.43±2.83)%]、Bax mRNA表达水平[(12.73±3.96)、(25.12±6.42)、(104.96±26.77)、(154.04±3052),(14.63±3.57)、(36.75±3.67)、(272.26±66.11)、(846.12±243.36),(14.75±5.65)、(37.22±11.27)、(278.51±37.42)、(861.67±369.29)]、Bax蛋白表达水平[(15.07±0.83)%、(23.79±3.99)%、(3851±158)%、(53.86±124)%,(15.43±1.45)%、(36.11±1.37)%、(56.86±1.97)%、(76.09±2.01)%,(15.20±1.03)%、(35.25±1.09)%、(55.56±2.17)%、(74.48±2.85)%]均随着染毒剂量的增加而增高(P均<0.05),而bcl-2 mRNA表达水平[(443.00±244.47)、(156.79±53.18)、(62.13±13.66)、(23.10±6.44),(420.55±110.77)、(48.15±10.02)、(14.91±6.53)、(7.54±2.62),(577.75±123.22)、(49.68±10.11)、(12.41±1.28)、(7.22±1.89)]、bcl-2蛋白表达水平[(47.20±3.77)%、(41.80±2.94)%、(36.00±2.36)%、(29.00±2.91)%,(45.90±4.15)%、(35.70±2.77)%、(29.80±2.78)%、(24.80±2.66)%,(46.70±3.47)%、(36.20±2.90)%、(30.10±3.21)%、(25.10±2.28)%]均随着染毒剂量的增加而降低(P均<0.05);在染砷3、9、15 mmol/L时,p53组的细胞凋亡率、bcl-2 mRNA表达水平、bcl-2蛋白表达水平均高于同一染砷剂量的正常组和PC组(P均<0.05),而Bax mRNA表达水平、Bax基因蛋白表达水平均低于同一染砷剂量的正常组和PC组(P均<0.05).结论 p53基因减少了NaAsO2致HELF的凋亡,可能是通过改变部分凋亡途径实现.     

三氧化二砷对人体胃肠癌细胞凋亡及p53、survivin表达的影响

目的研究三氧化二砷（arsenic trioxide,As2O3）在人体内诱导胃肠癌细胞凋亡作用及对凋亡相关基因p53、survivin表达的影响,探讨其抗肿瘤作用及发生机制。方法采用原位末端转移酶标记技术（TUNEL）和免疫组化法分别检测As2O3用药前后胃肠癌细胞凋亡指数和凋亡相关基因蛋白P53、Survivin的表达变化情况。结果 As2O3用药后胃肠癌细胞凋亡指数为（17.04±3.67）%,与用药前（6.07±2.21）%相比差异有统计学意义（P〈0.01）;用药后胃肠癌细胞P53蛋白阳性表达率为（35.05±19.64）%,与用药前（34.80±16.48）%相比差异无统计学意义（P〉0.05）;用药后胃肠癌细胞Survivin蛋白阳性表达率为（15.59±3.94）%,与用药前（36.74±20.5）%相比明显下调,差异有统计学意义（P〈0.01）;As2O3作用后胃肠癌细胞Survivin蛋白表达下调时凋亡率升高,二者之间具有相关性（r=-0.47,P=0.04）。结论 As2O3在人体内可诱导胃肠癌细胞凋亡而发挥抗肿瘤作用,其机制可能与下调survivin基因的表达有关。     

白血病细胞p53和bcl-2表达与化疗药物诱导凋亡的关系

目的　探索p5 3和bcl 2表达及化疗药物体外诱导白血病细胞凋亡与患者化疗疗效的关系。方法　用免疫组化法测定 42例急性白血病患者骨髓细胞p5 3和bcl 2表达水平 ;用TdT介导的脱氧核苷酸切口和末端标记法 (Tunel法 )、Wright Giemsa染色及超微结构观察等方法检测化疗药物诱导的白血病细胞凋亡。结果　 42例急性白血病患者p5 3和bcl 2总体表达水平显著高于对照组。2 7例随访组患者完全缓解 (CR) 16例 ,未缓解 (NR) 11例。CR者表现以p5 3和bcl 2共同阴性及化疗诱导高凋亡为主 ,NR者以p5 3和bcl 2共同阳性及化疗诱导低凋亡占优势。形态学观察可见典型细胞凋亡特征。结论　检测急性白血病患者p5 3和bcl 2表达水平及体外化疗药物诱导白血病细胞凋亡的敏感性有助于预测患者的化疗效果。     

Killing of p53-deficient hepatoma cells by parvovirus H-1 and chemotherapeutics requires promyelocytic leukemia protein

AIM： To evaluate the synergistic targeting and killing of human hepatocellular carcinoma （HCC） cells lacking p53 by the oncolytic autonomous parvovirus （PV） H-1 and chemotherapeutic agents and its dependence on functional promyelocytic leukemia protein （PML）. METHODS： The role of p53 and PML in regulating cytotoxicity and gene transfer mediated by wild-type （wt） PV H-1 were explored in two pairs of isogenic human hepatoma cell lines with different p53 status. Furthermore, H-1 PV infection was combined with cytostatic drug treatment. RESULTS： While the HCC cells with different p53 status studied were all susceptible to H-1 PV-induced apoptosis, the cytotoxicity of H-1 PV was morepronounced in p53-negative than in p53-positive cells. Apoptosis rates in p53-negative cell lines treated by genotoxic drugs were further enhanced by a treatment with H-1 PV. In flow cytometric analyses, H-1 PV infection resulted in a reduction of the mitochondrial transmembrane potential. In addition, H-1 PV cells showed a significant increase in PML expression. Knocking down PML expression resulted in a striking reduction of the level of H-1 PV infected tumor cell death. CONCLUSION： H-1 PV is a suitable agent to circumvent the resistance of p53-negative HCC cells to genotoxic agents, and it enhances the apoptotic process which is dependent on functional PML. Thus, H-1 PV and its oncolytic vector derivatives may be considered as therapeutic options for HCC, particularly for p53-negative tumors.     

Early apoptosis and cell death induced by ATX-S10Na （ Ⅱ ）-mediated photodynamic therapy are Bax- and p53-dependent in human colon cancer cells

AIM： To investigate the roles of Bax and p53 proteins in photosensitivity of human colon cancer cells by using lysosome-localizing photosensitizer, ATX-S10Na （Ⅱ）. METHODS： HCT116 human colon cancer cells and Bax-null or p53-null isogenic derivatives were irradiated with a diode laser. Early apoptosis and cell death in response to photodynamic therapy were determined by MTT assays, annexin Ⅴ assays, transmission electron microscopy assays, caspase assays and western blotting. RESULTS： Induction of early apoptosis and cell death was Bax- and p53-dependent. Bax and p53 were required for caspase-dependent apoptosis. The levels of anti-apoptotic Bcl-2 family proteins, Bcl-2 and Bcl-xL, were decreased in Bax- and p53-independent manner. CONCLUSION： Our results indicate that eady apoptosis and cell death of human colon cancer cells induced by photodynamic therapy with lysosome-localizing photosensitizer ATX-S10Na （Ⅱ） are mediated by p53- Bax network and low levels of Bcl-2 and Bcl-xL proteins. Our results might help in formulating new therapeutic approaches in photodynamic therapy.     

食管黏膜凋亡增殖和p53表达的增龄变化与食管鳞癌的关系

目的探讨食管黏膜增殖凋亡和p53表达的增龄变化以及这些变化与食管鳞癌的关系。方法按年龄分层选择连续胃镜检查对象818例,男414例,女404例。分为青中年组（258例）、老年前期组（296例）和老年组（264例）,进行食管活组织检查,应用TUNEL法检测凋亡指数（AI）,免疫组化法检测增殖指数（PI）和p53表达。结果食管正常上皮→单纯增生→轻中重度异型增生→鳞癌的发展过程中,AI等级逐渐下降,PI等级和p53表达逐渐增高。在食管正常上皮中,AI等级青中年组〉老年前期组〉老年组;PI等级比较,老年前期组分别高于青中年组和老年组（P〈0.01）;p53表达在老年前期组和老年组均高于青中年组（P〈0.01）。非条件logistic回归分析,食管鳞癌独立危险因素为增龄、PI等级和p53表达。当食管黏膜PI等级明显增高伴p53阳性时,鳞癌检出率明显增高,轻中重度异型增生有增高趋势,老年人尤为突出。结论食管黏膜正常上皮随增龄出现增殖凋亡和p53表达变化,与食管黏膜癌变过程变化相似,老年人食管黏膜PI明显增高伴p53阳性可作为食管鳞癌和癌前病变进一步随访和筛查的线索。     

The role of XPB in cell apoptosis and viability and its relationship with p53, p21 and c-myc in hepatoma cells

BACKGROUND: Accumulation of DNA damage has been implicated in hepatocarcinogenesis. XPB plays a pivotal part in repairing damaged DNA. However, up to now, the biological effect of XPB on hepatoma cells remains elusive. MATERIALS AND METHODS: Here, we investigated the role of XPB in the apoptosis and the viability of hepatoma cells by using the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labelling and cell viability assay; we also investigated their relationship with p53, p21(waf1/cip1) and c-myc by using the RT-PCR and Western blot. RESULTS: Compared with the control cells HepG2/pcDNA3.1 or HepG2, XPB-transfected HepG2 cells (HepG2/pcDNA3.1-XPB) displayed lower viability, weaker activity and higher apoptosis index. At the same time, an increased expression of p21(waf1/cip1) mRNA, protein and p53 protein in addition to a decreased expression of c-myc mRNA and protein were detected in HepG2/pcDNA3.1-XPB cells. CONCLUSIONS: Our results indicated that XPB could inhibit the proliferation of hepatoma cells and had a positive effect on the expression of p53 and p21(waf1/cip1) but a negative effect on c-myc.     

重组人p53腺病毒感染对携带不同p53状态胃癌细胞增殖和凋亡的影响

目的研究重组人p53腺病毒感染不同p53状态胃癌细胞对其p53蛋白表达、生长抑制率、细胞周期与凋亡率的影响。方法不同浓度重组人p53腺病毒感染3种不同p53状态胃癌细胞,即含野生型p53基因的细胞(wild-type)、含突变型p53基因的细胞(mutant-type)、含空载质粒即p53基因缺失的细胞(vector-cell)。48 h后,用Western blotting法检测p53蛋白在3种胃癌细胞中的表达;用MTT法测定重组人p53腺病毒感染3种胃癌细胞的生长抑制率,用流式细胞仪检测细胞周期分布和凋亡率。结果rAd-p53感染3种胃癌细胞48 h后p53蛋白表达阳性,对照组p53基因缺失的胃癌细胞无表达,对照组含野生型p53基因的细胞和含突变型p53基因的细胞弱表达。rAd-p53对3种胃癌细胞的生长抑制效应在一定的浓度范围内呈剂量依赖性,而与细胞内在的p53状态无关。含野生型p53基因的细胞、含突变型p53基因的细胞和p53基因缺失的细胞感染rAd-p53后诱导G2/M期阻滞与细胞凋亡率分别增加2.5、3.6、3.2倍。结论腺病毒介导p53基因感染3种不同p53状态胃癌细胞改变细胞内在的p53状态,p53蛋白表达、生长抑制率、细胞周期分布、凋亡率均与细胞内在的p53状态无关。     

The influence of the p53 gene on the in vitro chemosensitivity of colorectal cancer cells

Purpose : The p53 gene is considered one of the most important in the control of apoptosis, and its mutations have a close relationship with chemosensitivity. The aim of this work was to investigate the role of p53 in the apoptosis of colorectal cancer cells in vitro, induced by 5-fluorouracil (5-FU) and hydroxy-camptothecin (HCPT). Methods : A total of 39 colorectal cancer samples from patients were treated in vitro with 5-FU (10 μg/ml), 5-FU (10 μg/ml) + leucovorin (5 μg/ml), HCPT (0.1 μg/ml) and HCPT (0.1 μg/ml) + Salvia mitorrhiza (6 μl), using an in situ terminal deoxynucleotidyltransferase assay to detect chemosensitivity. p53 gene mutations from tumor DNA were detected, after amplification by the polymerase chain reaction of exons 5–8, by non-radioactive single-strand conformation polymorphism. Results : p53 gene mutations were observed in 43.6% (17/39) of colorectal carcinomas, when the terminal deoxynucleotidyltransferase assay was used to detect the tumor apoptotic rate. Cells with mutated p53 had lower chemosensitivity than those without (p < 0.01). Conclusion : Routine assessment of p53 status may be helpful in selecting patients with the wild-type p53 gene, who have a predictably better response to chemotherapy. Received: 18 November 1997 / Accepted: 17 December 1998     

腺病毒介导的人野生型p53、GM-CSF和B7-1基因转移诱导肝癌细胞的生长抑制和凋亡

目的 观察携带人野生型p53、GM－CSF和B7－1基因的重组腺病毒载体（BB－102）转染BEL－7402、HLE及HuH-7肝癌细胞后p53基因的表达,以及诱导肝癌细胞凋亡,影响肝癌细胞的增殖。方法 BB－102以MOI为50pfu/细胞感染肝癌细胞系BEL－7402（p53基因为野生型）、HLE及HuH-7(p53基因为突变型）。免疫组织化学法检测BB－102携带的p53基因的表达,TdT法原位检测肝癌细胞的凋亡。结果 BB－102携带的p53基因能在转染了BB－102的肝癌细胞中高效表达。转染BB－102后肝癌细胞生长明显受到抑制;染毒后第4－10d期间,BEL－7402、HLE及HuH-7三株肝癌细胞的平均受抑率分别为58．5％、81．5％及71．1％,其中对p53基因突变的肝癌细胞的抑制程度要大于对p53基因为野生型肝癌细胞的抑制程度。转染BB－102还能诱导肝癌细胞的凋亡。结论 BB－102通过其介导p53基因的表达抑制肝癌细胞的增殖,这为BB－102应用于肝癌的基因治疗提供实验依据。     

玉米苞叶对动脉粥样硬化家兔血管平滑肌细胞凋亡及Bcl-2和p53蛋白表达的影响

目的探讨玉米苞叶煎剂对实验性动脉粥样硬化(AS)家兔血管平滑肌细胞(VSMCs)凋亡及凋亡相关基因Bcl-2和p53蛋白表达的影响。方法选用大耳白家兔,利用高脂饲料复制家兔动AS模型,随机分为模型组、玉米苞叶煎剂组和正常对照组。实验9 w后确认两组动物造模成功,其中一组给予玉米苞叶煎剂治疗,28 m l/kg.d-1(玉米苞叶1.4 g/m l),实验17 w后,处死家兔,观察主动脉内膜的病理形态学改变,采用流式细胞术检测VSMCs凋亡率以及凋亡相关基因Bcl-2和p53蛋白表达。结果模型组VSMCs凋亡率明显高于对照组(P<0.05),p53和Bcl-2蛋白表达均增强(P<0.05),肉眼观察,主动脉内膜出现典型的AS斑块,动脉管腔极度狭窄。玉米苞叶煎剂组VSMCs凋亡率明显降低(P<0.05);p53和Bcl-2蛋白表达均下调(P<0.05);主动脉斑块面积较模型组明显减小,动脉管腔狭窄减轻。结论玉米苞叶通过影响p53和Bcl-2蛋白表达而影响AS家兔VSMCs凋亡;同时缩小AS斑块面积,具有显著治疗家兔AS作用。