P53及其最新发现概要ppt课件.ppt

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1、黄永业P53的简单介绍（1） p53p53基因是基因是一种肿瘤抑制基因一种肿瘤抑制基因，定位于人类，定位于人类1717号染号染色体短臂色体短臂，编码，编码p53p53磷蛋白。磷蛋白。p53p53磷蛋白的正常功磷蛋白的正常功能是能是调控细胞增殖调控细胞增殖。P53的简单介绍（2） 现在已经证明，p53蛋白是人体内最有效的对抗肿瘤的自然防御物。对抗肿瘤的自然防御物。 中国已经批准了用于人类癌症的首用于人类癌症的首个基因治疗。个基因治疗。正常细胞中正常细胞中P53P53的活动的活动 已知的P53与细胞凋亡关系示意图 p53和癌症 在p53上的变异可导致将近半数的人类癌症。 大多数的这些突变是错义突变

2、，它可以改变DNA一个位点上的信息，导致细胞产生错误的p53基因，使蛋白质链上某位点被错误的氨基酸所替换。在这些突变中，p53的正常功能被阻遏了从而在受损细胞中蛋白质也不能停止复制。如果这个细胞还有其他导致失控增殖的突变，那么最终将导致肿瘤。 P53新发现新发现P53新发现新发现 MDMXMDMX的遗传放大导致的遗传放大导致p53p53在视网膜母细胞瘤在视网膜母细胞瘤中失活中失活 p53p53泛素化的新机制被发现泛素化的新机制被发现 p53p53蛋白两种作用之间的关系蛋白两种作用之间的关系 p53p53参与肿瘤与基质间的对话参与肿瘤与基质间的对话 P53P53细胞凋亡机制重要新发现细胞凋亡机制

3、重要新发现MDMXMDMX的遗传放大导致的遗传放大导致p53p53在视网膜母在视网膜母细胞瘤中失活细胞瘤中失活(1)(1)题目：Inactivation of the p53 pathway in retinoblastoma源自：Nature2006年11月2日443卷7114期 来自：美国研究人员 MDMXMDMX的遗传放大导致的遗传放大导致p53p53在视网膜母在视网膜母细胞瘤中失活细胞瘤中失活(2)(2)摘要:在多数人类肿瘤中，细胞肿瘤抑制基因在多数人类肿瘤中，细胞肿瘤抑制基因RbRb 和和p53p53是失是失活的。该规则的一个例外是视网膜母细胞瘤活的。该规则的一个例外是视网膜母细胞瘤

4、（retinoblastomaretinoblastoma），在这种肿瘤中，仅仅视网膜母细胞），在这种肿瘤中，仅仅视网膜母细胞瘤基因的突变，就足以从不要求瘤基因的突变，就足以从不要求p53p53失活的一种固有的抗失活的一种固有的抗死亡细胞类型诱发肿瘤。死亡细胞类型诱发肿瘤。但这种观点可能是基于一个误解。人类视网膜母细胞但这种观点可能是基于一个误解。人类视网膜母细胞瘤表达野生型瘤表达野生型p53p53基因，所以过去人们假设基因，所以过去人们假设p53p53通道是完好通道是完好的：在的：在Arf-MDM2/MDMX-p53Arf-MDM2/MDMX-p53通道中的其他基因的状态没有通道中的其他基因

5、的状态没有被考虑被考虑. .现在，研究人员在人类视网膜母细胞瘤中识别出了一现在，研究人员在人类视网膜母细胞瘤中识别出了一种遗传放大现象，它能抑制种遗传放大现象，它能抑制Arf-MDM2/MDMX-p53Arf-MDM2/MDMX-p53通道。重通道。重要的是，由放大的基因编码的蛋白（要的是，由放大的基因编码的蛋白（MDMXMDMX）可能是对付少）可能是对付少儿癌症的药物的一个理想的作用目标。儿癌症的药物的一个理想的作用目标。 MDMXMDMX的遗传放大导致的遗传放大导致p53p53在视网膜母在视网膜母细胞瘤中失活（细胞瘤中失活（3 3）原文：Most human tumours have ge

6、netic mutations in their Rb and p53 pathways, but retinoblastoma is thought to be an exception. Studies suggest that retinoblastomas, which initiate with mutations in the gene retinoblastoma 1 (RB1), bypass the p53 pathway because they arise from intrinsically death-resistant cells during retinal de

7、velopment. In contrast to this prevailing theory, here we show that the tumour surveillance pathway mediated by Arf, MDM2, MDMX and p53 is activated after loss of RB1 during retinogenesis. RB1-deficient retinoblasts undergo p53-mediated apoptosis and exit the cell cycle. Subsequently, amplification

8、of the MDMX gene and increased expression of MDMX protein are strongly selected for during tumour progression as a mechanism to suppress the p53 response in RB1-deficient retinal cells. Our data provide evidence that the p53 pathway is inactivated in retinoblastoma and that this cancer does not orig

9、inate from intrinsically death-resistant cells as previously thought. In addition, they support the idea that MDMX is a specific chemotherapeutic target for treating retinoblastoma.p53p53泛素化的新机制被发现（泛素化的新机制被发现（1 1）题目：E4F1 Is an Atypical Ubiquitin E4F1 Is an Atypical Ubiquitin Ligase that Modulates p5

10、3 Effector Ligase that Modulates p53 Effector Functions Independently of Functions Independently of Degradationp775Degradationp775源自：CellCell November 17, 2006: 127 (4) 来自：法国，德国，西班牙等国家的学者 p53p53泛素化的新机制被发现（泛素化的新机制被发现（2 2）摘要:p53的功能被多种翻译后修饰机制所调控，包括Hdm2介导的泛素化作用，该作用可使其蛋白酶体降解。目前学者发现，P53P53相关因子相关因子E4F1E4F1

11、可以可以作为一个不典型的作为一个不典型的E3E3泛素链接酶，调控泛素链接酶，调控p53p53效应，并且该过程不依赖于效应，并且该过程不依赖于P53P53的降解的降解该研究证实了E4F1是p53的一个重要的翻译后修饰调控因子，并通过对p53功能的调控，影响着细胞的命运：究竟是生长停滞究竟是生长停滞还是凋亡还是凋亡。这一发现对于未来进一步研究p53的功能具有重要意义。p53p53泛素化的新机制被发现（泛素化的新机制被发现（3 3）原文：Figure 1. E4F1 Exhibits Intrinsic Ubiquitin E3 Ligase Activity on p53 In Vitro and

12、 In Vivo (A) Autoubiquitylation activity of E4F1. Autoradiograms of in vitro ubiquitylation assays performed under standard conditions in presence of in vitro translated (IVT) E4F1 labeled by 35S-methionine. (B) Recombinant E4F1 stimulates p53 ubiquitylation in vitro. Autoradiograms of in vitro ubiq

13、uitylation assays performed with IVT 35S-labeled p53 and GST-E4F1 or GST. (C) Autoradiograms of in vitro ubiquitylation assays performed under standard conditions with IVT 35S-labeled p53 and cellular E4F1 immunoprecipitated from E4F1- or mock-transfected U2OS cells. (D) E4F1 stimulates K48-Ub branc

14、hing. Autoradiograms of in vitro ubiquitylation assays performed with IVT 35S-labeled p53, baculovirus expressed E4F1 and Ub (WT), or Ub mutants bearing mutations of all (K0) or all but one of its lysine residues at the indicated position. Equal amounts of Ub mutants were used in each assay (Figure

15、S1F). (E) Cre-induced E4F1-GFP expression in U2OS cells stably expressing the LSL-E4F1 construct. (Upper panels) Western blot analyses of nuclear extracts prepared from LSL-E4F1 cells at the indicated time points after infection with Cre retrovirus, probed with anti-GFP, -E4F1, -p53 (DO1), -Cre, and

16、 -TBP (loading control) antibodies (Abs). (Lower panels) Analysis of E4F1-GFP expression by fluorescence microscopy 3 days after infection with Cre (+) or control () retroviruses. Cells are shown at 40 magnification. (F) E4F1 stimulates ubiquitylation of endogenous p53 in vivo. Western blot analyses

17、 of Ub-conjugated proteins in LSL-E4F1 cells transiently transfected for 24 hr with a 6XHis-Ub expression vector 4 days after infection by Cre (+) or control () retroviruses. One percent of cellular extracts were probed for the presence of E4F1-GFP and total endogenous p53 using anti-GFP and anti-p5

18、3 (DO1) Abs (input). These cellular extracts, normalized to contain equal amounts of total p53, were loaded on nickel (Ni+)-NTA columns. Ni+-purified 6XHis-Ub-conjugated proteins were probed for the presence of Ub-p53 forms using an anti-p53 (DO1) Ab (Ni-purified). Neither cells nor cellular extract

19、s were treated with proteasome inhibitors. (G) Depletion of endogenous E4F1 impacts on endogenous p53 ubiquitylation in vivo. Western blot analyses of Ub-conjugated proteins in U2OS cells treated for 72 hr with control scramble or E4F1 SiRNAs. His-Ub-conjugated forms of endogenous p53 present in the

20、se cells were purified and analyzed as described in Figure 1F. p53p53蛋白两种作用之间的关系（蛋白两种作用之间的关系（1 1） 题目：The two sides of p53 源自： Nature2006年9月14日 来自：美国加州大学旧金山分校的研究人员 p53蛋白两种作用之间的关系（2）摘要：p53蛋白是脊椎动物DNA损伤响应和肿瘤抑制的一个重要调控因子。总体上，这两种作用被认为是有因果关系的：p53通过对肿瘤细胞中的DNA损伤或基因组异常做出响应以及触发生长抑制或细胞凋亡来抑制肿瘤。现在，Christophoru等人利用

21、一个能够可逆转换的内生p53小鼠模型，发现病理性的由p53诱导的对辐射的响应，与由p53调控的对由这种辐射所诱导的肿瘤的抑制无关 p53蛋白两种作用之间的关系（3）原文：原文：Thetwosidesofp53The protein p53 is an important mediator of the DNA damage response and tumour suppression in vertebrates. In general, these two attributes are thought to be causally linked: p53 suppresses tumour

22、s by responding to DNA damage or genome abnormalities in tumour cells and triggering growth arrest or apoptosis. Now using a reversibly switchable endogenous p53 mouse model, Christophorou et al. show that the pathological p53-induced response to irradiation is irrelevant to p53-mediated suppression

23、 of tumours induced by that irradiation. Conversely, restoring p53 at later times avoids the pathological effects of irradiation but provides much of the tumour suppression. These data suggest that the DNA damage response and tumour suppression are unlinked activities of p53, each induced by distinc

24、t signals. A similar conclusion is drawn from a separate experiment, the absence of the tumour suppressor protein ARF was found to abolish the extra cancer-protective activity of an additional copy of p53 in mice. Again, this suggests that oncogenic signalling is critical for triggering protection b

25、y p53, whereas activation of p53 as a result of DNA damage has a lesser impact on the final development of tumours. In News and Views, Anton Berns looks at the implications of these findings for models of p53 activity.p53p53参与肿瘤与基质间的对话（参与肿瘤与基质间的对话（1 1） 题目：Pioneering Study Looks at p53s Pioneering St

26、udy Looks at p53s Role in Tumor-Stroma InteracRole in Tumor-Stroma Interac 源自：癌基因(Oncogene) 2006年11月 来自：美国爱莫力大学 (Emory University)科学家 p53p53参与肿瘤与基质间的对话（参与肿瘤与基质间的对话（2 2） 摘要： 研究人员以恶性神经胶质瘤 (glioma)为研究的工具，深入的分析p53 基因与细胞分泌蛋白质间的分子活动，结果研究人员找到了111 个相关的分泌蛋白质，其中有39个蛋白质，在正常的 p53基因活动时，会受到活化而增加分泌，另外则有 21个蛋白质受到了抑

27、制，然而其奇怪的是居然没有一个蛋白质，参与p53 基因的转录(transcriptional) 活动，可见得p53的基因活动，不仅仅受限于它自己是一个转录分子 (transcription factor)，还可能直接或是间接的参与肿瘤与组织间的对话，因而促成了肿瘤的生长。 p53参与肿瘤与基质间的对话（参与肿瘤与基质间的对话（3）Researchers at Emory Universitys Winship Cancer Institute have conducted the first comprehensive study of the role an important tumor

28、suppressor gene plays in cancer development. P53 is known as a major tumor suppressor that is frequently mutated in human cancer. In this study, researchers used novel proteomic techniques to identify the proteins secreted by cells specifically in response to p53. The findings suggest a newfound rol

29、e for wt-p53 in the control of the tumors ability to communicate with the normal stromal cells surrounding it. The results of the study, Proteomic identification of the wt-p53-regulated tumor cell secretome, are found in the October 9 advance online print of Oncogene. Cancer formation is traditional

30、ly thought of as a cell-autonomous process driven by mutations in genes that increase cell proliferation and survival, where a tumor is composed primarily of transformed cells, says Erwin G. Van Meir, PhD, Professor of Neurosurgery and Hematology/Oncology and lead-author of the study. But increasing

31、 evidence suggests that the tumor microenvironment also contributes to neoplasm and that tumor-stroma interactions play a major role in tumor development, maintenance, and progression. A tumor is more like a casserole of chili than a bowl of white rice, where all the components in the mix interact.

32、We need to better understand these tumor-stroma interactions to develop more effective cancer therapies. But little is know about how the genetic changes that underlie cell transformation elicit extrinsic changes that modulate cell interactions. So, the researchers examined whether those events invo

33、lve a modification in the cells secreted proteins, which then act as mediators of intercellular communication. Focusing on p53 as a proof-of-principle was a natural starting point as p53 is a transcription factor that directly controls the synthesis of numerous proteins. p53 is best known for its ro

34、le in maintaining genomic integrity and cell survival in response to DNA damage. Yet some prior studies suggested that p53 could influence the tumor microenvironment by suppressing angiogenesis and tumor invasion. To identify p53-regulated secreted proteins involved in intercellular communication, t

35、he researchers used a cell line derived from a malignant human glioma. The researchers found a total of 111 secreted proteins, 39 that showed enhanced secretion and 21 that showed inhibited secretion in response to wt-p53 expression. However, none of the proteins were found to be transcriptional tar

36、gets, which suggests that wt-p53 may have an indirect role in intracellular protein trafficking and secreted-protein stability, says Dr. Van Meir. These secreted targets will be helpful in better understanding how wt-p53 may modulate interactions of tumor cells with their environment and establishes

37、 p53 loss in tumors as a major trigger of changes in tumor-stroma interactions. A better understanding of these phenomena will improve our ability to devise new therapies for cancer. The study was funded by the American Brain Tumor Association, the Pediatric Brain Tumor Foundation of the US, the Nat

38、ional Institutes of Health, and the National Science Foundation. The team of researchers included Winship Cancer Institute and Emory University School of Medicines Dr Erwin G. Van Meir, Fatima W. Khwaja, Ph.D., Paul Svoboda, Ph.D., Matthew Reed, Ph.D., Jan Pohl and Beata Pyrzynska, Ph.D. Cell：P53细胞凋

39、亡机制重要新发现（细胞凋亡机制重要新发现（1）题目：TIGAR, a p53-Inducible Regulator of Glycolysis and ApoptosisDRAM, a p53-Induced Modulator of Autophagy, Is Critical for Apoptosis源自：Cell 2006年7月14日来自：英国Beatson癌症研究所和西班牙Unitat de Bioquimica I Biologia Molecular研究人员 英国Beatson癌症研究所和其他四个研究机构的合作研究 Cell：P53细胞凋亡机制重要新发现（细胞凋亡机制重要新发现

40、（2） 第一篇：第一篇：TIGARTIGAR，细胞凋亡和糖酵解的一种，细胞凋亡和糖酵解的一种p53p53诱导调节因子诱导调节因子 摘要：现在，研究人员确定出一种叫做TIGAR（TP53诱导糖酵解和凋亡调节因子）的p53诱导基因。TIGAR的表达降低了在细胞中果糖-2,6-磷酸盐（fructose-2,6-bisphosphate）的水平，从而抑制糖酵解并使细胞内活性氧总体水平下降，使细胞在面对温和或可逆转、修复的瞬间压力信号时能够存活下来 Cell：P53细胞凋亡机制重要新发现（细胞凋亡机制重要新发现（3） 第二篇：第二篇：p53p53诱导的自我吞噬调节因子诱导的自我吞噬调节因子DRAMDRA

41、M，细胞凋，细胞凋亡的关键亡的关键 摘要：研究人员描述了一种p53的靶标基因DRAM，这个基因编码一种诱导细胞死亡吞噬（p53介导的一种细胞死亡机制）的溶酶体蛋白。 研究人员证实p53通过一种依赖DRAM的放射诱导细胞自我吞噬，并且当只有DRAM发生过表达时会导致最小限度的细胞凋亡。也就说DRAM是p53介导的细胞凋亡的关键因子。 而且，对肿瘤中DRAM的分析结果显示，DRAM表达的减少常伴随着野生型p53的保留。这些研究不但发现自我吞噬的一种压力诱导调节因子，而且还突出了DRAM和自我吞噬到p53功能和损伤诱导的程序性细胞凋亡之间的关系。Cell：P53细胞凋亡机制重要新发现（细胞凋亡机制重

42、要新发现（4）The Beatson Institute for Cancer Research, Switchback Road, Glasgow G61 1BD, UK.The p53 tumor-suppressor protein prevents cancer development through various mechanisms, including the induction of cell-cycle arrest, apoptosis, and the maintenance of genome stability. We have identified a p53-i

43、nducible gene named TIGAR (TP53-induced glycolysis and apoptosis regulator). TIGAR expression lowered fructose-2,6-bisphosphate levels in cells, resulting in an inhibition of glycolysis and an overall decrease in intracellular reactive oxygen species (ROS) levels. These functions of TIGAR correlated

44、 with an ability to protect cells from ROS-associated apoptosis, and consequently, knockdown of endogenous TIGAR expression sensitized cells to p53-induced death. Expression of TIGAR may therefore modulate the apoptotic response to p53, allowing survival in the face of mild or transient stress signa

45、ls that may be reversed or repaired. The decrease of intracellular ROS levels in response to TIGAR may also play a role in the ability of p53 to protect from the accumulation of genomic damage.PMID: 16839880 PubMed - indexed for MEDLINEP53的其他一些新发现的其他一些新发现 研究发现研究发现p53突变致癌的分子机理突变致癌的分子机理 2006-10-19 p53基因给人类带来祸福：抑制肿瘤和基因给人类带来祸福：抑制肿瘤和加速衰加速衰老2006-8-29 P53的前景 目前，p53与其他的控制细胞凋亡的途径之间的直接联系还不清楚，相信将来这些关系会被进一步的弄清！谢谢老师和同学的关心与支持！ 谢谢！