1、恶性肿瘤的分子生物学图1 卵巢肿瘤A:GAe组雏鸡接种MDV GA株后40天,卵巢形成明显肿瘤(如箭头所示);B:GA0组卵巢正常(如箭头所示);C:异常卵巢和正常卵巢的直观比较)图2 睾丸肿瘤A:GA0组睾丸正常(如箭头所示);B:GAe组雏鸡接种MDV GA株后40天,睾丸形成明显肿瘤(如箭头所示);C:异常睾丸和正常睾丸的直观比较)l对肿瘤发生的分子机制,最初人们认为是对肿瘤发生的分子机制,最初人们认为是病毒瘤基因病毒瘤基因所致;所致;l7070年代中期,毕晓普和瓦慕斯发现动物正年代中期,毕晓普和瓦慕斯发现动物正常细胞中本来存在常细胞中本来存在癌基因(原癌基因)癌基因(原癌基因);l正常
2、情况下,瘤基因对细胞的生长、分化、正常情况下,瘤基因对细胞的生长、分化、调节和维护正常功能起重要作用;调节和维护正常功能起重要作用;l近来发现细胞中有抑制肿瘤发生的近来发现细胞中有抑制肿瘤发生的抑瘤基抑瘤基因因。The vast majority of these mutations are somaticExampleOncogenes derived from growth factor receptors confer the ability to bypass the growth factor requirementleading to independent growth.Act
3、as a brake for cell division“GUARDIAN OF THE GENOME”PROBLEM:Mutation in tumour suppressor genes=brakes dont work,or there is an accumulations of mutations(DNA repair enzymes)The mutated gene product is not functional=NULL ALLELEInactivated tumour suppressor gene肿瘤发生肿瘤发生Activated proto-oncogeneEffect
4、or cytotoxic T lymphocytes(CTLs)attach to these molecules and are nonspecifically recruited from the bloodstream into non-lymphoid tissues.例如:膀胱癌EJ株C-Ha-ras基因外显子12密码子的突变4 抑癌基因的作用及其致癌机制外源性抗原经APC摄取后,在溶酶体中降解为短肽,由MHC类分子提呈给CD4+T细胞;Dendritic cells(DCs)take up antigen by distinct endocytosis mechanisms and
5、 present it to CD4+T helper(TH)cells through MHC class II molecules and cross-present it to CD8+cytotoxic T lymphocytes(CTLs)through MHC class I molecules.近来发现细胞中有抑制肿瘤发生的抑瘤基因。DC需要经历由不成熟向成熟阶段的转变才能有效刺激T细胞活化。例如:膀胱癌EJ株C-Ha-ras基因外显子12密码子的突变Chemokine-mediated regulation of cross-priming is illustrated.c-M
6、YC over-expressed in colon cancer此外,DC还通过延伸其树突状突起,增加与T细胞相互作用的机会。the t(9;22)(q34;q11)reciprocal translocationHelpless CTLs activated by unlicensed DCs die following secondary encounter with antigen in their effector phaseAPC(腺瘤样结肠息肉)RET-MEN 2a对肿瘤发生的分子机制,最初人们认为是病毒瘤基因所致;A:GA0组睾丸正常(如箭头所示);是机体在各种致瘤因素作用下,
7、局部组织的细胞在基因水平上失去对其生长的正常调控,导致克隆性异常增生而形成的新生物分子肿瘤学认为恶性肿瘤是一种涉及基因改变的疾病3 癌基因致癌的分子机制含转录含转录启动子启动子 LTR gag pol env src LTR 长末端长末端重复序列重复序列癌基因癌基因正常的病毒基因正常的病毒基因 产生病毒产生病毒表面糖蛋白表面糖蛋白产生逆转录产生逆转录酶和整合酶酶和整合酶 产生病毒产生病毒 垮膜蛋白垮膜蛋白产生产生p60p60srcsrc蛋白质,蛋白质,磷酸化蛋白。靶蛋磷酸化蛋白。靶蛋白磷酸化白磷酸化Rous于于1910年首先发现鸡肉瘤病毒(后称劳年首先发现鸡肉瘤病毒(后称劳斯肉瘤病毒斯肉瘤病毒
8、RSV)基因扩增基因扩增蛋白质结构未变化,但总量大大提高蛋白质结构未变化,但总量大大提高基因扩增基因扩增 原癌基因原癌基因基因在细胞中拷贝数增加,从而使可用的转基因在细胞中拷贝数增加,从而使可用的转录模板数大大增加。录模板数大大增加。染色体易位或重排染色体易位或重排慢性粒细胞白血症慢性粒细胞白血症(Chronic myeloid leukaemia,CML)is characterised bythe t(9;22)(q34;q11)reciprocal translocation病毒启动子插入病毒启动子插入基因间相互作用基因间相互作用 肿瘤细胞中常常不是由一种肿瘤细胞中常常不是由一种C-on
9、c表达异常,表达异常,有时需几种有时需几种C-onc发生改变,产生协同作用方发生改变,产生协同作用方可奏效可奏效 正常情况下这两类信号保持着动态平衡,十分精确地调控细胞增殖和成熟。70年代中期,毕晓普和瓦慕斯发现动物正常细胞中本来存在癌基因(原癌基因);它的失活或突变具有促进肿瘤生长的潜势。Oncogenes(癌基因)基因在细胞中拷贝数增加,从而使可用的转录模板数大大增加。C:异常睾丸和正常睾丸的直观比较)Rous于1910年首先发现鸡肉瘤病毒(后称劳斯肉瘤病毒RSV)Loss of both copiesBenign tumors arise with great frequency but
10、 pose little risk because they are localized and small正向调控信号:主要是起促进细胞生长和增殖,并且阻止其发生终末化倾向,癌基因起着这方面的作用。守门基因(gatekeeper gene)是指在细胞恶性转化过程中与癌基因启动相关的基因。Tumour suppressor genes(肿瘤抑制基因)Recruitment of cross-primed effector cytotoxic T lymphocytes into non-lymphoid tissues.恶性肿瘤细胞在生物学研究中的应用正常情况下这两类信号保持着动态平衡,十分精
11、确地调控细胞增殖和成熟。RB1-retinoblastoma susceptibility gene守门基因(gatekeeper gene)是指在细胞恶性转化过程中与癌基因启动相关的基因。Chemokine-mediated regulation of cross-priming is illustrated.肿瘤有良性、恶性之分。借助交叉递呈机制,APC可以主动摄取病毒蛋白或肿瘤抗原,并通过MHC类分子将抗原呈递给CD8+T细胞,从而产生有效的CTL应答,达到清除靶细胞的目的。正常细胞的基因,具有相对稳定的甲基正常细胞的基因,具有相对稳定的甲基化类型,特别是原癌基因的甲基化可使其难化类型,
12、特别是原癌基因的甲基化可使其难以表达。以表达。原癌基因甲基化水平降低原癌基因甲基化水平降低Examples of Oncogenes正常情况下抑癌基因的作用:正常情况下抑癌基因的作用:抑癌基因改变的分子基础抑癌基因改变的分子基础错配修复基因缺陷错配修复基因缺陷 守门基因和看护基因的突变失活守门基因和看护基因的突变失活 守门基因守门基因(gatekeeper gene)是指在细胞恶是指在细胞恶性转化过程中与癌基因启动相关的基因。性转化过程中与癌基因启动相关的基因。看护基因看护基因(caretaker,gene)是指保持细胞是指保持细胞基因组稳定性,而与细胞恶性转化过程中癌基基因组稳定性,而与细胞
13、恶性转化过程中癌基因的启动不直接相关的基因。因的启动不直接相关的基因。Examples of tumour suppressor genes includeRB1-retinoblastoma susceptibility gene WT1-Wilms tumour gene NF1-neurofibromatosis type 1 gene NF2-neurofibromatosis type 2 gene DCC-involved in colorectal cancer BRCA1,BRCA2-involved in breast cancerToday we will look at
14、these tumour suppressor genes:Rb()p53APC(腺瘤样结肠息肉腺瘤样结肠息肉)A:GA0组睾丸正常(如箭头所示);70年代中期,毕晓普和瓦慕斯发现动物正常细胞中本来存在癌基因(原癌基因);Gatekeeper genes抑癌基因(tumorsuppressor gene,TSG)它的失活或突变具有促进肿瘤生长的潜势。是机体在各种致瘤因素作用下,局部组织的细胞在基因水平上失去对其生长的正常调控,导致克隆性异常增生而形成的新生物Mutation in tumour suppressor genes=brakes dont work,or there is an a
15、ccumulations of mutations(DNA repair enzymes)是指能导致细胞恶性转化的核酸片段。Second,when specific CD4+T helper(TH)cells detect microbial(or self)antigen on non-cross-presenting tissue DCs,ligands for CC-chemokine receptor 5(CCR5)or CXC-chemokine receptor 3(CXCR3)are produced that recruit CTLs into the infected tis
16、sue.抑癌基因在染色体中起稳定性作用;正向调控信号:主要是起促进细胞生长和增殖,并且阻止其发生终末化倾向,癌基因起着这方面的作用。它的失活或突变具有促进肿瘤生长的潜势。B:GAe组雏鸡接种MDV GA株后40天,睾丸形成明显肿瘤(如箭头所示);PROTO-ONCOGENES近来发现细胞中有抑制肿瘤发生的抑瘤基因。基因在细胞中拷贝数增加,从而使可用的转录模板数大大增加。恶性肿瘤细胞在生物学研究中的应用Benign tumors arise with great frequency but pose little risk because they are localized and small
17、除了侵占正常细胞所占的空间外,还发生扩散和转移,形成新的病灶。In this figure,dashed arrows indicate antigen routing for crosspresentation.p53 functions as a molecular node in the DNA-damage response恶性肿瘤细胞在生物学研究中的应用恶性肿瘤细胞在生物学研究中的应用 无限制增长特性无限制增长特性 细胞分化幼稚细胞分化幼稚 细胞寿命长细胞寿命长 细胞的侵润性细胞的侵润性 致瘤性致瘤性 细胞的遗传性细胞的遗传性蛋白质结构未变化,但总量大大提高TUMOUR SUPRES
18、SOR GENES负向调控信号:主要使细胞成熟,促进终末分化,最后是细胞调亡,抑癌基因则在这方面起作用。c-MYC over-expressed in colon cancerRET-MEN 2aDCC-involved in colorectal cancerThe CCR4-and CCR5-mediated recruitment pathways are synergistic.借助交叉递呈机制,APC可以主动摄取病毒蛋白或肿瘤抗原,并通过MHC类分子将抗原呈递给CD8+T细胞,从而产生有效的CTL应答,达到清除靶细胞的目的。The CCR4-and CCR5-mediated rec
19、ruitment pathways are synergistic.Mutation in tumour suppressor genes=brakes dont work,or there is an accumulations of mutations(DNA repair enzymes)Helpless CTLs activated by unlicensed DCs die following secondary encounter with antigen in their effector phase近来发现细胞中有抑制肿瘤发生的抑瘤基因。抑癌基因(tumorsuppressor
20、 gene,TSG)恶性肿瘤细胞在生物学研究中的应用有时原癌基因中一个核苷酸的突变会使基因表达异常的蛋白产物,从而使细胞向恶性转化。参与衰老过程,诱导细胞程序性死亡;蛋白质结构未变化,但总量大大提高它的失活或突变具有促进肿瘤生长的潜势。1989年诺贝尔生理学或医学奖Clonal selection of cancer cellsVariants over timeActivated proto-oncogene肿瘤细胞中常常不是由一种C-onc表达异常,有时需几种C-onc发生改变,产生协同作用方可奏效借助交叉递呈机制,APC可以主动摄取病毒蛋白或肿瘤抗原,并通过MHC类分子将抗原呈递给CD8
21、+T细胞,从而产生有效的CTL应答,达到清除靶细胞的目的。B:GAe组雏鸡接种MDV GA株后40天,睾丸形成明显肿瘤(如箭头所示);1989年诺贝尔生理学或医学奖借助交叉递呈机制,APC可以主动摄取病毒蛋白或肿瘤抗原,并通过MHC类分子将抗原呈递给CD8+T细胞,从而产生有效的CTL应答,达到清除靶细胞的目的。RB1-retinoblastoma susceptibility geneAct as a brake for cell divisionA:GA0组睾丸正常(如箭头所示);抑癌基因在染色体中起稳定性作用;Licensed DCs upregulate expression of c
22、o-stimulatory molecules,such as CD70,CD80 and CD86,and downregulate inhibitory molecules,such as programmed cell death ligand(PDL1).TLR具有激活DCs,增强其抗原交叉递呈的能力。一旦这两类信号中有一类信号过强或过弱均会使细胞生长失控而恶变。正常情况下主要在胚胎期表达,在出生后的个体内不表达或限量表达,主要功能是促进细胞的正常增殖和分化,又称原癌基因,被致癌因素激活时,可诱导细胞癌变。而不仅异常快速增殖,而且细胞可发生扩散转移的称为恶性肿瘤,特称为癌(cancer
23、)或新生物(neoplasm)。外源性抗原经APC摄取后,在溶酶体中降解为短肽,由MHC类分子提呈给CD4+T细胞;交叉递呈在机体抗病毒及其它病原体感染和肿瘤免疫等方面起着非常重要的作用。是指能导致细胞恶性转化的核酸片段。Rous于1910年首先发现鸡肉瘤病毒(后称劳斯肉瘤病毒RSV)The molecular mechanisms involved in classical cross-priming are illustrated.Dendritic cells(DCs)take up antigen by distinct endocytosis mechanisms and prese
24、nt it to CD4+T helper(TH)cells through MHC class II molecules and cross-present it to CD8+cytotoxic T lymphocytes(CTLs)through MHC class I molecules.Activated CD4+TH cells can stimulate CTLs through the production of interleukin-2(IL-2)and license DCs for cross-priming through CD40 ligand(CD40L)CD40
25、 interactions.Licensed DCs upregulate expression of co-stimulatory molecules,such as CD70,CD80 and CD86,and downregulate inhibitory molecules,such as programmed cell death ligand(PDL1).Toll-like receptor(TLR)ligands further activate DCs and increase their cross-presentation activity.Cross-primed CTL
26、s are programmed for survival and cease TNF-related apoptosis-inducing ligand(TRAIL)production.Helpless CTLs activated by unlicensed DCs die following secondary encounter with antigen in their effector phaseChemokine-mediated regulation of cross-priming is illustrated.CD4+TH cells,and the DCs they l
27、icense,produce CC-chemokine ligand 3(CCL3),CCL4 and CCL5 in the presence of TLR ligands,which recruit naive CTLs for classical cross-priming.Alternatively,DCs licensed by natural killer T(NKT)cells produce the CC-chemokine receptor(CCR4)ligand CCL17,and NKT cells themselves produce the CCR4 ligand C
28、CL22,which recruit naive CCR4+CTLs for cross-priming.The CCR4-and CCR5-mediated recruitment pathways are synergistic.In this figure,dashed arrows indicate antigen routing for crosspresentation.-GalCer,-galactosylceramide;TCR,T cell receptor.借助交叉递呈机制,APC可以主动摄取病毒蛋白或肿瘤抗原,并通过MHC类分子将抗原呈递给CD8+T细胞,从而产生有效的C
29、TL应答,达到清除靶细胞的目的。Loss of both copiesAct as a brake for cell division抑癌基因(tumorsuppressor gene,TSG)恶性肿瘤细胞在生物学研究中的应用Caretaker genesAlternatively,DCs licensed by natural killer T(NKT)cells produce the CC-chemokine receptor(CCR4)ligand CCL17,and NKT cells themselves produce the CCR4 ligand CCL22,which re
30、cruit naive CCR4+CTLs for cross-priming.纵向传播:原病毒随细胞分裂传递外源性抗原经APC摄取后,在溶酶体中降解为短肽,由MHC类分子提呈给CD4+T细胞;1976年,Bevan首先发现交叉递呈(cross-presentation)的现象,随后,Sigal等也揭示外源性抗原能有效被APC的MHC类分子递呈。细胞癌基因(cellular oncogenes,C-onc):存在于动物细胞中的癌基因。The CCR4-and CCR5-mediated recruitment pathways are synergistic.恶性肿瘤细胞在生物学研究中的应用I
31、n addition,recent studies have revealed two antigen-specific recruitment mechanisms:first,endothelial cells in certain tissues,such as the liver,pancreatic islets or the brain,can cross-present microbial antigen,which allows them to selectively recruit antigen-specific CTLs.DCC-involved in colorecta
32、l cancer是指能导致细胞恶性转化的核酸片段。Genetic Control of Neoplastic Initiation and PromotionTUMOUR SUPRESSOR GENESA:GA0组睾丸正常(如箭头所示);它的失活或突变具有促进肿瘤生长的潜势。不成熟DC捕获抗原后,在炎性因子的刺激下分化为成熟DC,细胞的抗原摄取能力下降,而抗原递呈及刺激T细胞活化的能力增强。Tumour suppressor genes(肿瘤抑制基因)Loss of both copiesB:GA0组卵巢正常(如箭头所示);4 抑癌基因的作用及其致癌机制守门基因(gatekeeper gene
33、)是指在细胞恶性转化过程中与癌基因启动相关的基因。此外,DC还通过延伸其树突状突起,增加与T细胞相互作用的机会。Mutation in tumour suppressor genes=brakes dont work,or there is an accumulations of mutations(DNA repair enzymes)Act as a brake for cell division交叉递呈在机体抗病毒及其它病原体感染和肿瘤免疫等方面起着非常重要的作用。Rb(视网膜母细胞瘤)CDK4-familial melanomaDendritic cells(DCs)take up a
34、ntigen by distinct endocytosis mechanisms and present it to CD4+T helper(TH)cells through MHC class II molecules and cross-present it to CD8+cytotoxic T lymphocytes(CTLs)through MHC class I molecules.B:GAe组雏鸡接种MDV GA株后40天,睾丸形成明显肿瘤(如箭头所示);它的失活或突变具有促进肿瘤生长的潜势。Act as a brake for cell divisionPROTO-ONCOG
35、ENES它的失活或突变具有促进肿瘤生长的潜势。70年代中期,毕晓普和瓦慕斯发现动物正常细胞中本来存在癌基因(原癌基因);Loss of both copiesRAS-activated in many cancers(colon)A:GA0组睾丸正常(如箭头所示);Dendritic cells(DCs)take up antigen by distinct endocytosis mechanisms and present it to CD4+T helper(TH)cells through MHC class II molecules and cross-present it to C
36、D8+cytotoxic T lymphocytes(CTLs)through MHC class I molecules.70年代中期,毕晓普和瓦慕斯发现动物正常细胞中本来存在癌基因(原癌基因);有时原癌基因中一个核苷酸的突变会使基因表达异常的蛋白产物,从而使细胞向恶性转化。它的失活或突变具有促进肿瘤生长的潜势。Activated proto-oncogeneMET-hereditary papillary renal cancer4 抑癌基因的作用及其致癌机制Mutation in tumour suppressor genes=brakes dont work,or there is a
37、n accumulations of mutations(DNA repair enzymes)借助交叉递呈机制,APC可以主动摄取病毒蛋白或肿瘤抗原,并通过MHC类分子将抗原呈递给CD8+T细胞,从而产生有效的CTL应答,达到清除靶细胞的目的。A:GA0组睾丸正常(如箭头所示);Dendritic cells(DCs)take up antigen by distinct endocytosis mechanisms and present it to CD4+T helper(TH)cells through MHC class II molecules and cross-present
38、 it to CD8+cytotoxic T lymphocytes(CTLs)through MHC class I molecules.B:GAe组雏鸡接种MDV GA株后40天,睾丸形成明显肿瘤(如箭头所示);Normal genes(regulate cell growth)交叉递呈在机体抗病毒及其它病原体感染和肿瘤免疫等方面起着非常重要的作用。正常情况下主要在胚胎期表达,在出生后的个体内不表达或限量表达,主要功能是促进细胞的正常增殖和分化,又称原癌基因,被致癌因素激活时,可诱导细胞癌变。守门基因(gatekeeper gene)是指在细胞恶性转化过程中与癌基因启动相关的基因。产生p6
39、0src蛋白质,磷酸化蛋白。Recruitment of cross-primed effector cytotoxic T lymphocytes into non-lymphoid tissues.Viral infection of tissue cells leads to their secretion of pro-inflammatory cytokines and interferons that upregulate the expression of adhesion molecules,such as intercellular adhesion molecule 1(I
40、CAM1),by endothelial cells.Effector cytotoxic T lymphocytes(CTLs)attach to these molecules and are nonspecifically recruited from the bloodstream into non-lymphoid tissues.In addition,recent studies have revealed two antigen-specific recruitment mechanisms:first,endothelial cells in certain tissues,
41、such as the liver,pancreatic islets or the brain,can cross-present microbial antigen,which allows them to selectively recruit antigen-specific CTLs.Second,when specific CD4+T helper(TH)cells detect microbial(or self)antigen on non-cross-presenting tissue DCs,ligands for CC-chemokine receptor 5(CCR5)or CXC-chemokine receptor 3(CXCR3)are produced that recruit CTLs into the infected tissue.LFA1,lymphocyte function-associated antigen 1;TCR,T cell receptor.