本文選題：胰腺癌 + 遺傳易感性��； 參考：《北京協(xié)和醫(yī)學(xué)院》2015年博士論文

【摘要】：全基因組關(guān)聯(lián)研究(GWAS)作為一種高通量的研究方法,近年來(lái)已幫助生物醫(yī)學(xué)研究者們發(fā)現(xiàn)了一些與胰腺癌易感性相關(guān)的基因及遺傳位點(diǎn),然而影響胰腺癌發(fā)生、發(fā)展的遺傳易感因素仍未被完全闡明。本研究利用中國(guó)人群胰腺癌全基因關(guān)聯(lián)研究數(shù)據(jù)進(jìn)行進(jìn)一步挖掘,鑒定新的與胰腺癌易感性相關(guān)的基因及單核苷酸多態(tài)(SNP),并運(yùn)用生物化學(xué)、分子生物學(xué)、細(xì)胞學(xué)等手段,對(duì)與胰腺癌易感性相關(guān)的基因及其SNP進(jìn)行生物學(xué)功能研究,以闡明其生物學(xué)作用機(jī)制。關(guān)聯(lián)研究采用全基因組篩查和驗(yàn)證兩階段設(shè)計(jì)。探討胰腺癌遺傳易感因素采用病例-對(duì)照研究策略。全基因組篩查階段包含981個(gè)病例和1,991個(gè)對(duì)照,驗(yàn)證階段包含2,869個(gè)病例和3,207個(gè)對(duì)照。胰腺癌全基因組篩查階段共發(fā)現(xiàn)78個(gè)P10-5的SNP,本研究篩選出10-6P10-5的46個(gè)SNP進(jìn)行獨(dú)立驗(yàn)證(P10-6的32個(gè)SNP的驗(yàn)證結(jié)果已經(jīng)發(fā)表)。我們發(fā)現(xiàn)位于17q24.3的rs11655237與胰腺癌發(fā)病風(fēng)險(xiǎn)顯著相關(guān)(P=3.95×10-11),與rs11655237G等位基因相比較,rs11655237A等位基因顯著增加了胰腺癌的發(fā)病風(fēng)險(xiǎn)(OR=1.26,95% CI=1.15-1.38)�；蚨ㄎ环治霭l(fā)現(xiàn),該位點(diǎn)位于LINC00673(基因間長(zhǎng)鏈非編碼RNA)基因的第4個(gè)外顯子區(qū)。生物學(xué)功能研究表明,rs11655237A等位基因向G等位基因的轉(zhuǎn)變,干擾了miRNA-1231與LINC00673的結(jié)合,進(jìn)而導(dǎo)致LINC00673表達(dá)升高。運(yùn)用LINC00673過(guò)表達(dá)和敲降的研究策略,以及RNA-Pulldown、RNA免疫共沉淀等實(shí)驗(yàn)方法,我們的研究結(jié)果證實(shí),LINC00673能夠與蛋白酪氨酸磷酸酶SHP2結(jié)合,并促進(jìn)其通過(guò)泛素化途徑降解,從而,一方面抑制具有促癌活性的SRC/ERK信號(hào)通路的活化,另外一方面激活STAT1依賴性的抗腫瘤應(yīng)答反應(yīng)信號(hào)通路。表型研究結(jié)果顯示,在LINC00673高表達(dá)的胰腺癌細(xì)胞系中,其細(xì)胞增殖、克隆形成以及裸鼠移植瘤生長(zhǎng)受到明顯的抑制；而在LINC00673低表達(dá)的胰腺癌細(xì)胞系中,這些惡性表型則得到了顯著的增強(qiáng)。上述結(jié)果表明,LINC00673作為一種抑癌基因在胰腺癌的發(fā)生、發(fā)展中發(fā)揮重要的調(diào)控作用,而位于其外顯子區(qū)的遺傳變異rs11655237則可能通過(guò)某些精細(xì)而復(fù)雜調(diào)節(jié)機(jī)制來(lái)影響其表達(dá),進(jìn)而修飾個(gè)體對(duì)胰腺癌的遺傳易感性。我們的研究結(jié)果對(duì)于闡明胰腺癌病因、鑒定高危個(gè)體、進(jìn)行早期診斷和早期干預(yù)具有重要理論意義和潛在的應(yīng)用價(jià)值。
[Abstract]:Genome-wide association study (GWAS), as a high-throughput method, has helped biomedical researchers in recent years to identify some genes and genetic loci associated with the susceptibility to pancreatic cancer, while affecting the occurrence of pancreatic cancer. The genetic susceptibility to development has not yet been fully elucidated. In this study, we further excavated the data of the whole gene association of pancreatic cancer in Chinese population, identified new genes and single nucleotide polymorphisms (SNPs) related to the susceptibility of pancreatic cancer, and used biochemistry, molecular biology, cytology and other methods. The biological function of genes and SNP associated with pancreatic cancer susceptibility were studied in order to elucidate its biological mechanism. The whole genome screening and validation two-stage design was used in the association study. To investigate the genetic predisposing factors of pancreatic cancer, a case-control study was used. The whole genome screening phase consisted of 981 cases and 1991 controls, while the validation phase consisted of 2 869 cases and 320 7 controls. A total of 78 SNPs of P10-5 were found in the whole genome screening stage of pancreatic cancer. In this study, 46 SNP of 10-6P10-5 were screened for independent validation of 32 SNP of P10-6. We found that the rs11655237 located in 17q24.3 was significantly associated with the risk of pancreatic cancer. Compared with the rs11655237G allele, the rs1165237A allele significantly increased the risk of pancreatic cancer by 1.2695% CI 1.15-1.38. The locus was located in the fourth exon of LinC00673 (intergenic long chain noncoding RNAs) gene. The study of biological function showed that the transformation of rs11655237A allele to G allele interfered with the binding of miRNA-1231 to LINC00673 and led to the increase of LINC00673 expression. Using the strategies of overexpression and knockdown of LINC00673 and RNA-Pulldown RNA immunoprecipitation, our results show that LinC00673 can bind to protein tyrosine phosphatase SHP2 and promote its degradation through ubiquitin pathway. On the one hand, the activation of SRC/ERK signaling pathway with carcinogenic activity was inhibited; on the other hand, the STAT1-dependent anti-tumor response signaling pathway was activated. Phenotypic studies showed that the proliferation, clone formation and growth of xenografts in nude mice were significantly inhibited in pancreatic cancer cell lines with high expression of LINC00673, but in pancreatic cancer cell lines with low expression of LINC00673. These malignant phenotypes were significantly enhanced. These results suggest that LinC00673 plays an important regulatory role in the development of pancreatic cancer as a tumor suppressor gene, while the genetic variation rs11655237 located in its exon may affect its expression through some fine and complex regulatory mechanisms. And then modify the individual genetic susceptibility to pancreatic cancer. Our results have important theoretical significance and potential application value in elucidating the etiology of pancreatic cancer, identifying high-risk individuals, early diagnosis and early intervention.
【學(xué)位授予單位】：北京協(xié)和醫(yī)學(xué)院
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：R735.9
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本文編號(hào)：1783931