厨卫电器十大排名兰主壁垫垄茎旦查垦兰堕.堡主兰垡垒!!一IFN.Y促进肿瘤免疫逃避及相关的肿瘤基因治疗
摘要
肿瘤的发生发展包括两个过程:首先是癌变,然后是增殖。在这两个过程中相应的细胞都不被免疫系统消灭才能最终形成肿瘤。不能被免疫系统消灭也正是肿瘤的一个重要特征,这其中包括许多的逃避机制,包括肿瘤细胞表面MHCI类分子的下调,分泌免疫抑制性因子如TNF-B,缺乏T细胞的共刺激信号以及在T细胞遇到肿瘤细胞时发生凋亡等等。
英语作文50词左右在此研究中,我们首先发现前炎症因子IFN.Y在持续低水平表达时能够促进肿瘤的发生发展,这种作用有一部分是通过诱导肿瘤的免疫逃避来实现的,即通过上调抑制性共刺激分子,!II]PD—i的配体PD-LI和PD—L2,CTLA一4,B7x/BTLA等的表达,使机体对肿瘤产生免疫耐受。IFN.Y促进肿瘤的发生发展的作用为我们提供了一种联系慢性炎症与肿瘤发生发展的新机制,而针对其诱导肿瘤免疫逃避机制的治疗则为我们提供了新的预防和治疗肿瘤的途径,包括抗炎治疗或者拮抗IFN—Y的治疗策略,以及对某些免疫抑制性信号的阻断,如PD—L,PD一1信号途径,B7x/BTLA信号途径等等。
左传名句在随后的研究中我们还发现,肿瘤的免疫逃避也在肿瘤的免疫基因治疗过程中加强,在应用趋化因子SLC进行肿瘤的局部基因治疗过程中,其对肿瘤的抑制率随着SLC表达量的增加而增强,但是,出乎
意料的是,最大的肿瘤完全抑制率发生在SLC低水平表达时。RT—PCR检测发现PD—L1和PD—L2基因都表达于肿瘤和瘤周组织,而且它们的表达水平随着SLC表达的增加而增加。然后我们构建了编码PD—l胞外段的质粒pPD.IA,局部基因转染pPD.IA表达PD—L的阻断剂可产生抗肿瘤效应并可明显增强SLC介导的抗肿瘤免疫。由于IFN~Y促进肿瘤发生发展,而它又是许多免疫治疗过程中的依赖因子,如在应用SLC
树间华中科技大学忍漭医学院博士学位论文
治疗肿瘤的过程中,所以IFN-v亦可能参与丁免疫治疗过程中的肿瘤免疫逃避。
熬=J=B7x/BTLA抑制性信号途径可能参与TIFN—y诱导的肿瘤免疫逃避,我们也通过局部表达负性受体BTLA的阻断剂,观察到了这种处理方式烂著增强抗瓣癜免疫,掷丧tld,鼠肿癌患长效馋用。此终。我们还通过联合基嚣漶疗的手段,观察到间时转染BTLA和PD一1受体的阻断剂,可明照提高其中单独的一种因子故治疗效粱。这秽谤冠馋熙也在联会应羁憝纯因子SLe嚣IFN—Y的壤凝裁治疗小鼠肝癌的实验中观察到。这些络果提示,针对肿瘸的一些免疫逃避机制进嚣联会基匿滚疗,能够遂一疹灌强壤体戆撬辨瘗g§力,篷褥进~步深入瑟究。
关于四季的诗在此论文中,我们还提到一个肿瘸基因治疗过程中的重要问题,即剂量与疗效靛关系。在我铜鹃实验中,我镧溪察裂tFN-Y翼有“双粥剑”作麓,邵低剂凝的持续液达主要表现为促进肿瘤的发生和发
展,而当高剂量表达时则主要表瑗为具蠢瓣翻瓣癌豹褥爱。焉对予趋纯因予SLC,箕稚翎瓣癌生长的作用是随袭达量增加而增加的,但完全抑制率却随之下降:对于趋他因子IP—lO丽言,捧麓效果在低蠢n燕时与高潮量前一样。因j琏:,对于不同的治疗性困予,在基因治疗的过程中,要针对其作用特点选择其含适的剂摄,最好能够采取联合基因治疗的方箴同时针对肿瘤兔疫逃避的机制“对症下药”,这样才能这到最佳的挽肿瘤效粱。
兰±壁垫垄兰璺查垦堂堕一!生兰垡堂生PromotingeffectofIFN吖ontumorimmuneevasion
andtherelatedtumorgenetherapy
Abstract
倚杖听江声Generallytherearetwostagesofcancerdevelopment:initiationandprogression.Ifcancercellsarenoteliminatedbytheimmunesystemduring
bothstages.theymaycontinuetogrowandthenfornlthetumor.Itisanimportanthallmarkofcancerstha
好景豪园
ttheycouldnotbeeliminatedbyimmunesystemandavarietyofimmuneevasionstrategiesaccountforcancerprogression.Theseincludedownregulationofcell-surfaceMHCclassImolecules,secretionofimmunosuppressivefactors(forexample,transfomlinggrowthfactor-13),lackofT-cellcostimulation,and,theprogrammedcelldeath(apoptosis)ofTcellswhenencounteringtumor.Inthisstudy.wefirstfoundthatsustainedlow-levelexpressionofIFN—Y,apotentproinflammatorycytokine,promotestumordevelopment.LowlevelofIFN—Vup—regulatesexpressionofPD—L1,PD·L2.CTLA-4andB7x,BTLA.whichmaypartlyaccountforthetumorimmuneevasionpromotedbyIFN—Y.OurfindingthatIFN-Ypromotestumordevelopmentprovidesamechanisticlinkbetweenchronicinflammationandcancerandalsoprovidesthepotentialapplicationsforcancerpreventionandtreat
mentbasedonthemechanismsoftumorimmuneevasion.Eitherstrategiesofanti·inflammatoryoranti-IFN—Vtherapy.orblockadeofsuchnegativeimmunepathwaysasPD·L/PD一1orB7“BTLAmaybeuseful
Inthefollowingstudieswefoundthattumorimmuneevasionwasenhancedduringimmunotherapy,Whenweuseddifferentdosageofaconstructedeukaryoticexpressionplasmid,pSLC,which
expressesfunctionalmurinesecondarylymphoidtissuechemokine(SLC,CCL21),to
treatBALB/cmiceinoculatedwithH22murinehepotomaceils,the
inhibitoryeffectwasenhancedalongwiththeincreaseofpSLCdosageUnexpectedly,
4
华中科技大学同济医学院博士学位论文
however,thebestcompleteinhibitionrateoftumorwasreachedwhenpSLCwasusedatthedosageof50Pgbutnot100Pgor200Pg.RT—PCRandsemi.quantitativeRT—PCRrevealedthatbothPD—L1andPD—L2geneswereexpressedintumorandvicinalmuscletissuesoftumor-bearingmiceandtheexpressionlevelwassignificantlyincreasedifhigherdosageofpSLCwasadministered.Wethenconstructedaeukaryoticexpressionplasmid(pPD一1A)thatexpressesextracelluardomainofmurinePD一1(sPD一1).
纯水和净水的区别BlockadeofPD—Ls—PD一1interactionsbylocalgenetransferofpPD一1AmediatedantitumoreffectandimprovedSLC—mediatedantitumorimmunity.AsIFN—vcanpromotetumordevelopmentanditisacytokineinvolvedinantitumormechanismsofmanyothercytokine
ssuchasSLCusedforimmunotherapy,wesupposethatIFN-vmayalsobeinvolvedinthemechanismsoftumorimmuneevasionduringimmunotherapy.AstheB7x/BTLAnegativepathwaymaybeinvolvedinthemechanismsoftumorimmuneevasionpromotedbyIFN-Y,wealsoobservedasignificantenhancedantitumorimmunitybylocallyexpressionofBTLAblockade.Furthermore,byusingthemethodofcombinedgenetherapy.co-expressionoftheblockadeofBTLAandPD一1significantlyenhancedtheantitumoreffectcomparedwiththesingleexpression.Alsosuchsynergisticeffectwasobservedwhenco-expressionofSLCandtheIFN.YblockadeinmiceinoculatedwithH22tumorcells.Takentogethertheseresultsindicatethatthemethodofcombinedgenetherapybasedonthemechanismsoftumorimmuneevasioncouldfurtherenhancetheantitumorimmunityandisworthtobefurtherstudied.
Inthisthesiswealsonoteanimportantissueincancer
genetherapy,thatis.thedose—effectrelationship.InourexperimentsweobservedthatIFN·Vfunctionsasa"two—edgedsword”:sustainedlow-levelexpressionofIFN—Vmainlyhastumor-promotingactivitywhilehighlevelofIFN.Ymainly
hastumorsuppressoractivity.AsforthechemokineSLC,theinhibito
ryeffectontumorisenhancedalongwiththeincreasedexpressionleve].However,it
竺!翌垫查兰旦堡墨堂堕堡主芏堡堕查
isnotthecaseforanotherchemokine.IP一10,whichhasthesimilarantitumor
effectwhenexpressedatloworhighlevel.Therefore,itis
importanttochoosetheoptimaldoseofdistincttherapeuticfactorsbasedontheiractionpatIern.Usingthemethodofcombinedgenetherapybasedonthemechanismsoftumorimmuneevasionmaybeobtainsthebestantitumoreffect
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