摘要
细胞周期素D1促进G1期细胞进程是通过刺激细胞周期依赖激酶(CDKs)介导的Rb蛋白的磷酸化作用而实现。细胞周期素D1被认为是一种癌基因。CDK4的酶活性又受一些抑制蛋白如p16的限制,后者是存在于染色体9p21上的CDKN2基因的产物,在多种肿瘤细胞系和原发肿瘤中频发缺失和突变,被认为是抑癌基因。为了解它们在食管癌发生发展中作用,用免疫组织化学及原位杂交方法,在41例原发食管癌中检测了Rb、p16、细胞周期素D1的蛋白表达及部分肿瘤中细胞周期素D1和p16基因的存在状态。26/41例(63.4%)显示细胞周期素D1过度表达,10例在对应的癌旁增生上皮也显示细胞周期素D1的过度表达。13/41例p16表达阴性,4例呈弱阳性。24例Rb阳性的标本中,17例显示p16不表达或低水平表达,而9例Rb表达阴性的标本均显示p16表达增高。结果提示,在食管癌形成过程中,细胞周期素D1是一常见的分子异常,并且可能是一早期分子事件,随即而来的分子改变可以是Rb的失活或/和p16的失活;Rb的失活与细胞周期素D1激活在食管癌中可共同存在;Rb失活与p16表达之间存在负相关关系;食管癌的分子发病机制可能涉及CDK4/细胞周期素?
D-typecyclinsbeingconsideredasoncogenespromoteprogressionofthecelthroughtheG1phaseofthecelcyclebyCDK4mediatedphosphorylationoftheretinoblastomaprotein.TheactivitiesofCDK4isconstrainedbyinhibitorssuchasp16,theproductoftheCDKN2intumorcelsandprimarytumorssuggeststhatp16actsasatumorsuppressor.Weexaminedtheseproteinsandgenesbyimmunohistochemistryandinsituhybridizationtechniquesin41primaryesophagealcancers.Overex-pressionofcyclinD1wasrevealedin26/41samples(63.4%)andalsointhemucosaadjacenttothecan-cersin10of26cyclinD1overexpressionsamples,whichalsohavehighlevelsofcyclinD1.P16wasunde-tectablein13of41samples.Interestingly,17of24Rbpositivecancershadnoorlowp16,while9Rb-negativecancersshowedhighlevelsofp16.TheseresultssuggestthattheoverexpressionofcyclinD1maybeacommonmolecularabnormalityandanearlymoleculareventinesophagealcancer,folowedei-therbyRbloss,asoccurredinRbnegativesamples,orbylossofp16,asoccurredinp16negativesam-ples.CyclinD1overexpressionandRbinactivationcancoexistinesophagealcancer.However,thereisareciprocitybetweenRbinactivationandp16expresioninesophagealcancer.Thus,abnormalityinthenegativefeedbackregulatorypathwayofcyclinD1/CDK4,Rbandp16maybeinvolvedinthemolecularmechanismofesophagealcancer.
出处
《中华病理学杂志》
CAS
CSCD
北大核心
1996年第6期336-339,共4页
Chinese Journal of Pathology
基金
国家攀登计划
八.五攻关基金