肿瘤侵袭和转移ppt课件

1、.,1,第八章肿瘤的侵袭和转移,本文由医学百事通高端医生网志愿者医师制作 ,.,2,肿瘤转移的基本过程 肿瘤转移的分子生物学 阻止肿瘤转移存在问题及发展方向,.,3,第一节 肿瘤转移的基本过程,一、肿瘤侵袭（tumor invasion) 指恶性肿瘤细胞从其起源部位沿组织间隙向周围正常组织扩张性增生的过程。其标志是肿瘤细胞突破基底膜 肿瘤侵袭生长行为有以下特点： 侵袭的肿瘤细胞能侵占和排挤周围正常组织，但瘤细胞并未与原瘤灶分离 对周围正常组织的功能有干扰或破坏,.,4,二、肿瘤转移（tumor metastasis) 个别瘤细胞能脱离原发肿瘤，通过侵润在周围间质中生长，通过淋巴管或血管迁移至其

2、他部位继续增殖生长，形成与原发肿瘤相同性质的继发肿瘤的全过程。 继发灶可再增殖，继发侵袭生长和形成新的肿瘤，并进一步发生转移，产生继续扩散和转移。 侵袭生长是癌组织扩张的先行活动，转移是瘤体达到一定数量和体积后才会出现的现象。转移时伴有侵袭生长，但侵袭生长并不一定发生转移，两者相辅相成。,.,5,三、肿瘤的侵袭生长和转移过程,早期原发癌的生长 肿瘤血管形成 肿瘤细胞脱落并侵入基质 进入脉管系统 癌栓的形成 继发组织器官定位生长 转移癌继续扩散,.,6,.,7,（一）、逃脱局部控制和侵润 转移的第一步就是破坏与邻近细胞的联系，摆脱邻近细胞的控制，穿过基质进入血管和淋巴管。 1、肿瘤细胞的增殖和扩

3、张 2、肿瘤细胞的分离与脱落,.,8,细胞粘附性状发生改变,正常细胞间的相互作用 细胞粘附：细胞-细胞， 细胞-细胞外基质 粘附关系：同质粘附-相同细胞间粘合 异质粘附-不同细胞或与细胞外基 质的粘合 粘附分子：同嗜粘合-粘合分子相同 异嗜粘合-粘合分子不同 癌细胞：同型识别的破坏和异型识别的变化是侵润和转移癌的特点,.,9,细胞外基质降解酶系统：降解细胞外基质，形成一条侵润和转移通路,丝氨酸蛋白酶：胰蛋白酶，凝血酶，纤溶酶，尿激酶型和组织型纤溶酶原激活因子，弹性蛋白酶 半胱氨酸蛋白酶 天冬酰氨蛋白酶 糖苷酶 基质金属蛋白酶,.,10,3、恶性肿瘤细胞的运动性和趋化性,癌细胞向邻近周围细胞移动

4、，贴近受侵细胞表面，表现为癌细胞表面伸出许多伪足贴附于受侵细胞 癌细胞伸出伪足，阿米巴样运动，向受侵组织细胞间隙生长侵入,.,11,（二）、内侵指肿瘤细胞从癌组织脱落侵入到血管中,1、转移途径 （1）血路转移 （2）淋巴路转移 （3）体腔,.,12,血流转移 一些肿瘤细胞可从原发部位分离脱落，浸透组织基底膜，穿透间质内血管壁 瘤细胞自血管壁游离，或形成细胞聚集体，脱落进入血循环，在循环中的肿瘤细胞大部分被迅速清除 存活的瘤细胞则随血循环运行，到达靶器官，在该器官小血管内与内皮细胞粘附、滞留 肿瘤细胞聚集体可在血管腔内增殖，或再穿过血管壁，先与细胞外基质粘附，进入靶器官实质，同实质细胞发生粘附，

5、在该处生长，形成微小转移灶 微小转移灶长至一定体积时，瘤组织血管新生，获得营养，进一步长大，形成转移瘤,.,13,特点： 动脉壁较厚，不易被侵犯；静脉和毛细血管壁薄，易侵犯；毛细血管内皮细胞周期性脱落更新，暴露基底膜 需蛋白酶消化基底膜 血流是一个恶劣环境，进入血流的癌细胞99以上会因机械压力，蛋白水解酶，宿主免疫系统监控而破坏 肿瘤细胞在血液中是以单个细胞或若干个癌细胞与淋巴细胞和附着的血小板形成复合物的方式运输 癌细胞与靶器官血管内皮细胞发生黏附，内皮细胞收缩，受损，暴露其下的基底膜，瘤细胞附着于基底IV型胶原上，转移出血管,.,14,（2）淋巴路转移,淋巴管特点： 淋巴管壁薄，无完整的基

6、底膜，易被癌细胞附着和穿入 内皮细胞间有暂时裂隙，利瘤细胞进入 淋巴液流动缓慢，在有外力作用下，易促进管内瘤细胞运动,.,15,转移路径,癌细胞穿透上皮基底膜，侵入结缔组织间隙 癌细胞开始向淋巴管靠近，并接触管壁 癌细胞穿过淋巴管内皮基底膜屏障，进入管腔内 癌细胞在淋巴管内移动 癌细胞通过输入淋巴管到达汇流区淋巴结，在淋巴结内滞留 癌细胞在淋巴结内继续生长，可破坏窦壁内皮，穿出淋巴窦，然后在淋巴结实质内增埴，破坏淋巴结的正常结构，终至全部为癌组织所取代,.,16,进入淋巴管内或淋巴结内癌细胞有2种命运 被血流中免疫T-cell,NK等杀死 极少数逃脱免疫杀伤并能快速生长,.,17,（3）体腔

7、腹膜和肺部的胸膜腔是转移的主要部位 腹膜腔内器官的癌症易在腹膜中扩散 腹腔内癌细胞外侵到达器官表面，挣脱并被腹膜液携带或直接与腔内其它位点接触 肺部肿瘤或其它位点转移来的转移灶，都能植入肺周围和胸膜之间的腔隙，产生胸膜渗出液,.,18,2、肿瘤转移的器官选择性,1889 Reget 提出“种子土壤”学说，认为肿瘤的转移是特殊的肿瘤细胞（种子）在适宜的环境（土壤）中生长发展的结果 1929 Ewing以器官的血液，淋巴的行流方向来解释转移的发生 乳腺癌的淋巴转移至腋窝淋巴结 肠胃道恶性肿瘤血行转移多经门静脉首先转移至肝脏 下肢皮肤癌及恶性黑色素瘤转移至腹股沟淋巴结,.,19,（1）血液循环的结构

8、特征能部分决定转移生长的位点 来自内脏的血液汇集于肝门静脉，通过肝，由心脏经肺重新分布 因此，肝和肺是癌转移的常见位点 （2）首先经过的器官 从原发位点通过血管最先遇到的器官经常是癌细胞继发生长的位点 肝是常见的转移位点 肺是头颈部癌症的转移位点,.,20,.,21,肿瘤细胞转移能力的影响因素 肿瘤细胞表面差异性 组织器官微环境差异 影响肿瘤转移器官选择性的相关因素,.,22,（三）、外侵逃避血管内的破坏，逃离并侵入新的环境,1、肿瘤细胞血管内锚定黏附 当癌细胞聚集体，淋巴细胞和血小板复合物黏附到毛细血管内皮细胞上时，锚定在内皮细胞表面 血小板与内皮细胞表面的纤维蛋白原相互作用，并通过P-选择

9、素与内皮聚糖蛋白相互作用 内皮E-选择素结合到癌细胞的聚糖蛋白上 肿瘤细胞和淋巴细胞上的41整合素，有利于癌细胞聚集体运动的停止，及与内皮的连接,.,23,2、从血管逃逸 内皮细胞回缩，暴露基底膜上的糖蛋白，癌细胞黏附其上，然后利用蛋白酶和糖苷酶将其消化 癌细胞前导边缘交替黏附到基质蛋白上，同时滞后的边缘交替脱离基质来完成迁移过程 基质蛋白质水解过程中释放的肽段也可作为趋化因子，吸引其它癌细胞到这个区域,.,24,3、定位生长 肿瘤细胞进入继发脏器的基质后，并不意味转移一定形成，只有当侵入继发脏器的肿瘤细胞增殖并长大，才真正完成转移 癌细胞在新的位点上增殖最初局限于直径1mm，要扩大生长，必须

10、形成新血管，来提供氧和营养 4、转移的休眠,.,25,.,26,.,27,第二节 肿瘤转移的分子生物学,一、基因调控下的肿瘤转移 肿瘤转移促进基因 Bcl-2, Myc, ras, raf, erbB-2 肿瘤转移抑制基因 Nm23, TIMP,.,28,1、 The nm23 gene family The first metastasis suppressor gene identified was nm23 Eight members of the human nm23 family have been reported and are found in multiple subcell

11、ular compartments.,.,29,2、 Biochemical functions nm23 proteins posses multiple biochemical functions Interaction with numerous proteins A NDPKinase activity DNA nuclease Serine or histidine protein kinase,.,30,3. Nucleoside diphosphate kinase activity The nm23-H1 gene product has been identified as

12、the NDPKA isoform The nm23-H2 gene product has been identified as the NDPKB isoform NDPKs: catalyze the phosphorylation of nucleoside diphosphates to the corresponding nucleoside triphosphates, mainly at the expense of the ATP synthesized through oxidative phosphorylation,.,31,The ping pong mechanis

13、m involves a conserved histidine, namely histidene118 in human enzymes, as a phosphorylated intermediate. All the eucaryotic NDPKs are hexamers (trimers of parallel dimers).,.,32,4. The role of nm23 in tumor metastasis Interactions of NDPKs, with other proteins may be important in the regulation of

14、the underlying biochemical mechanism by which NDPKs determine the metastatic fate of a tumor cell,.,33,Interaction with numerous protein Tiam1(a specific GEF for Rac1) NDPKA is able to regulate the activity of Rac1 NDPKA suppresses the activity of Tiam1 V-Src interacts with the N-terminal region of

15、Tiam1, NDPKA could interfere with this binding , modulating the GEF acting of Tiam1 by control of its binding to the plasma membrane,.,34,Interactions regulating the activity of small GTPase NDPK regulates the MAPK pathway by modulating the phosphorylation site of the kinase suppressor of Ras (KSR)

16、NDPKA functions as a GAP of Rad,.,35,Interaction with transcription factors,.,36,(2) Interaction with cytoskeletal protein NDPK modulates cell shape-dependent processes involved in development, cell proliferation, differentiation and invasion and metastasis of tumor cells preventing Rac/Rho activati

17、on by blocking the GDP-exchange function of Tiam1, by preventing Src to bind to Tiam1 by regulation the local GTP/GDP-blance in protein complexes modulating the phosphorylation of amino acid of IFs,.,37,(3) DNA nuclease A model: the transcriptional regulation was explained by an intrinsic nuclease-l

18、ike activity of NDPK,NDPKB could cleave both linear and supercoiled double-stranded DNA at a sequence specific site, resulting in a covalently bound enzyme-DNA complex energy of this covalent bond could be used to religate the DNA,.,38,(4) serine, histedine protein kinase Histidine phosphorylation P

19、hosphohistidine is formed by a N-P phosphoramidate bond . Phosphorylation of the 1 and 3 nitrogens has been detected. Histidine kinases form a phospho-histidine intermediate, which then transfers the phosphate to the substrate,.,39,nm23-H1 phosphorylation on Ksr serine 392, a 14-3-3 binding site, an

20、d on serine 434 in conjunction with the serine 392 mutation. Ksr is thought to be a scaffold molecule for the Erk Map kinase signaling pathway. Histidine kinase activity of nm23-H1 is required for inhibition of the Map kinase pathway and correlated with motility suppression.,.,40,.,41,二、黏附因子与肿瘤转移,(一

21、) cell junctions Many cells in tissues are linked to one another and to the extracellular matrix at specialized contact sites called cell junctions,.,42,Occluding junctions seal cells together in an epithelium in a way that prevents even small molecules from leaking from one side of the sheet to the

22、 other,.,43,2. Anchoring junctions Mechanically attach cells to their neighbors or to the extracellular matrix,.,44,(1). Connect the cytoskeleton of a cell either to the cytoskeleton of its neighbors or to the extracellular matrix,.,45,(2). Anchoring junctions occur in two functionally different for

23、ms Adherens junctions and desmosomes hold cells together and are formed by transmembrane adhesion proteins that belong to the cadherin family Focal adhesions and hemidesmosomes bind cells to the extracellular matrix and are formed by transmembrane adhesion proteins of the integrin family Adherens ju

24、nctions and focal adhesions serve as connection sites for actin filaments Desmosomes and hemidesmosomes serve as connection sites for intermediate filaments,.,46,.,47,.,48,3. Communicating junctions Mediate the passage of chemical or electrical signals from one interacting cell to its partner Gap ju

25、nctions allow small molecules to pass directly from cell to cell,.,49,A summary of the various cell junctions,.,50,(二) cell-cell adhesion To form anchoring junction, cells must first adhere Animal cells can assemble into tissue either in place or after they migrate Dissociated vertebrate cells can r

26、eassemble into organized tissues through selective cell-cell adhesion,.,51,CAMs cell adhesion molecules cell-cell adhesion molecules cell-matrix adhesion molecules Ca 2+ -dependent Ca 2+ -independent,.,52,1、Cadherins mediate Ca2+-dependent cell-cell adhesion,.,53,Structure The Ca2+ ions are position

27、ed between each pair of cadherin repeats,locking the repeats together to form a stiff, rodlike structure: the more Ca2+ ions that are bound , the more rigid the structure is. If Ca2+ is removed, the extracellular part of the protein becomes floppy and is rapidly degraded by proteolytioc enzyme.,.,54

28、,b. Cadherins mediate cell-cell adhesion by a homophilic mechanism,.,55,c. Cadherins are linked to the actin cytoskeleton by catenins,.,56,2、Selectins mediate transient cell-cell adhesion in the bloodstream Selectins are cell-surface carbohydrate-binding protein (lectins) that mediate a variety of t

29、ransient, ca2+-dependent, cell-cell adhesion interactions in the bloodstream. L-selectin E-selectin P-selectin,.,57,.,58,3、Members of the Ig superfamily of proteins mediate Ca2+-independent cell-cell adhesion N-CAM (neural cell adhesion molecule) I-CAM(intercellular adhesion molecule),.,59,4、Integri

30、ns Binding most ECM proteins Integrins are transmembrane heterodimers,.,60,Integrins must interact with the cytoskeleton to bind cells to the extracellular matrix,.,61,.,62,Summary,.,63,.,64,.,65,（三）、the extracellular matrix of animals The matrix has a far more active and complex role in regulating

31、the behavior of the cells that contact it, influencing the survival, development, migration, proliferation, shape, and function,.,66,（1）The extracelluar matrix is made and oriented by the cells within it Glycosaminoglycans (GAGS)/proteoglycans Fibrous proteins: collagen, elastin, fibronectin, lamini

32、n,.,67,1) Glycosaminoglycans/proteoglycans Glycosaminoglycan(GAG) chains occupy large amounts of space and form hydrated gels,Structure:,.,68,four groups: hyaluronan chondroitin and dermatan sulfate heparan sulfate keratan sulfate function: form porous hydrated gels fill most of extracellular space

33、provide mechanical support to the tissue Co-receptors,.,69,hyluronan is thought to facilitate cell migration during tissue morphogenesis and repair,.,70,proteoglycans are composed of GAG chains covalently linked to a core protein,.,71,GAG chains may be highly organized in the extracellular matrix,.,

34、72,2) Fibrous proteins collagens are the major proteins of the xetracellular matrix Secreted by connective tissue cells and a variety of other cell types Major component of skin and bone The most abundant protein in mammals,Structure,.,73,classification,.,74,The formation of a collagen fibril Collag

35、ens are secreted with a nonhelical extension at each end After secretion , fibrillar procollagen molecules are cleaved to collagen molecules, which assemble into fibrils Fibril-associated collagens help organize the fibrils,.,75,elastin gives tissues their elasticity,.,76,fibronectin is an extracell

36、ular protein that helps cells attach to the matrix,.,77,laminin,.,78,3. Basal laminae are compose mainly of type IV collagen, laminin, nidogen, and a heparan sulfate proteoglycan,.,79,Function: separate cell to cell and tissue to tissue filtering roles determine cell polarity influence cell metaboli

37、sm organize the proteins in adjacent plasma membrane promote cell survival, proliferation, differentiation serve as specific highway for cell migration The basal lamina is synthesized largely by the cells that on it Is tethered to the underlying connective tissue by specialized anchoring fibrils mad

38、e of type VII collagen molecules,.,80,.,81,A model of the molecular structure of a basal lamina,.,82,4. The controlled degradation of matrix components helps cell migrate Cells migrate through a basal lamina, require degradation of matrix components matrix components are degraded by extracellular pr

39、oteolytic enzymes (proteases) that are secreted locally by cells The proteolysis of matrix proteins can contribute to cell migration in several ways It can simply clear a path through the matrix It can expose cryptic sites on the cleaved proteins that promote cell binding, cell migration or both It

40、can promote cell detachment so that a cell can move onward It can release extracellular signal proteins that stimulate cell migration,.,83,(四)、cadherins,Cadherin comprise an important group of cell-cell adhesion molecules that mediate intercellular adhesion by Ca2+-dependent homophilic interactions.

41、 By forming homedimers, cadherin can cluster through a zipper-like mechanism, while their intracellular domain is anchored to the actin cytoskeleton through and catenin.,.,84,.,85,1、cadherins （1）、Classification more than 80 members of the cadherin superfamily have been identified in the human genome

42、. Including: classic cadherins, fat-like cadheins, seven-pass transmembrane cadherins Classic cadherins: E-, N-, P-,cadherin A subfamily of cadherins that share a common primary structure and bind to cateins through conserved cytoplasmic domains.,.,86,Fat-like cadherins: FAT-1 and FAT-2 A subfamily

43、of cadherins that contain large tandem arrays(19-34) of extracellular cadherin domain and an EGF domain. Seven-pass transmembrane cadherins: A subfamily of cadherins that show some similarity to the secretin family of G-protein-linked receptors and contain eight to nine extracellular cadherin domain

44、s, two globin domains and four EGF domains. Also present is a domain called the Flamingo box, which is located between the last extracellular cadherin domain and the first EGF domain and is highly conserved across species in this subfamily.,.,87,Cadherins are traditionally calssified according to th

45、e tissue distribution or to the origin from which they discovered. the cadherin seen in epithelial cells is named as E-CD In heart as H-CD In neural tissues as N-CD Most of the cadherins are found in a variety of tissues. These cadherins are therefore reclassified according to the structural and fun

46、ctional similarities which they share, as cadherin 1-12,.,88,（2） Structure Extracellular CD domain: 5 tandem repeats, mediate Ca2+-dependent homophilic interactions: from disordered cadherin structure to a rigid rod-like structure (cis dimer) and then a trans dimer of multiple cis dimers, the trans

47、dimers forming zipper structure Transmembrane domain: 35 aa Cytoplasmic domain of classic CDs: two portions,.,89,.,90,（3）E-CD The human E-CD gene(CDH1) is situated on chromosome 16q22.1 E-CD forms from a 135KD precursor that undergoes cytoplasmic trimming of what will become the extracellular N-term

48、inal end of the mature molecule The mature E-CD,weighting approximately 120KD,.,91,The first catenin to interact with E-CD is -catenin Followed by binding of -catenin to a short region close to NH2-terminal of - catenin At last, forming stable bonds between the complex and the actin cytoskeleton P12

49、0ctn is responsible for modulation of CD clustering and thus the stabilization of adhesion,.,92,.,93,2、catenins Catenins are a group of cytoplasmic proteins which interact with the intracellular domain of the cadherin molecule, providing anchorage to the microfilament cytoskeleton. -catenin 102KD -c

50、atenin 88KD -catenin (plakoglobin) 82KD P120ctn 120KD,.,94,3、Two distinct E-CD-catenin complex E-CD, -catenin and -catenin E-CD, -catenin and -catenin,.,95,4、the relationship between regulation of E-CD-catenin complex and tumor metastasis （1）External factors regulate E-CD-catenin complex The interfe

51、rence with complex assembly seems to be mediated by a mitogenic signal transmitted by EGFR through its tyrosine kinase resulting in tyrosine phosphorylation of - catenin and E-CD itself. The end result is dissociation of - catenin from E-CD-catenin complex and translocation of free - catenin to the

52、cytosolic pool,.,96,（2）Members of the small GTPase family regulate E-CD-catenin complex,Regulation of Rho-family GTPases The small GTPase family: the Ras the Rho subfamily: Rho, Rac1, cdc42,.,97,Possible modes of action of Rho GTPase in the regulation of E-cadherin-mediated cell-cell adhesion Rac1/C

53、dc42 and IQGAP1 can regulate E-CD activity IQGAP1 is localized to sites of cell-cell contact and it negatively regulates E-CD-mediated cell-cell adhesion by interacting with - catenin, with causes -catenin to dissociate from the cadherin-catenin complex Activated Rac1 and Cdc42 positively regulate c

54、adherin-mediated cell-cell adhesion by inhibiting the interaction of IQGAP1 with - catenin,.,98,E-CD exists in dynamic equilibrium between the E-CD- - catenin- -catenin complex and the E-CD- - catenin- IQGAP1 complex at sites of cell-cell cntact When the amounts of activated Rac1 and Cdc42 increase

55、binging to IQGAP1 inhibiting the interaction of IQGAP1 with - catenin the E-CD- - catenin- -catenin complex is high Strong adhesion activity When the amounts of inactivated Rac1 and Cdc42 increase IQGAP1 is free Intercating with - catenin to dissociate -catenin from the cadherin-catenin complex the

56、E-CD- - catenin- IQGAP1 complex is high Resulting in weak adhesion abd cell-cell dissociation,.,99,.,100,Cadherin recycling E-CD cleavage by metalloproteinases,.,101,（3） Wnt-1 signaling pathway The increased pool of - catenin, have an effect on cell adhesion with the - catenin in the cytosolic pool

57、either linking with E-CD or acting in the Wnt-1 pathway the - catenin combine with LEF/TCF, causing transcription of the cyclinD1 gene and downregulation of the CDH1 gene. The net result of all these interaction is a reduction in E-CD-mediated cell adhesion and proliferation of cells.,.,102,.,103,（4

58、）、 summary,.,104,（5）、The role hypoxia in E-CD regulation and metastasis,.,105,5、changes of cadherin complex in cancer,Reduction in cell adhesion is of major importance in tumor metastasis and appears to be achieved by a variety of mechanisms affecting the E-CD-catenin complex Including: Reduced leve

59、l of CD Abnormal location of E-CD Mutation of E-CD Shedding of E-CD Mutation and abnormal level of - catenin Abnormalities of - catenin Change of - catenin binding partners Changes of protein phosphorylation E-CD complex is directly involved in the benign to malignent transition,.,106,（五）、integrins,Integrins are heterodimeric (/ subunits) cell surface glycoproteins that bind to ECM proteins outside of the cell, and connect ,via their cytoplasmic domains,to components of the actin cytoskeleton within the cell. Members of the integrin family of cell adhesion re