本文選題：結(jié)直腸癌 + 長鏈非編碼RNA　； 參考：《南方醫(yī)科大學》2017年碩士論文

【摘要】：結(jié)直腸癌為消化道常見的惡性腫瘤之一,是繼肺癌、胃癌和肝癌之后的第四大癌癥死亡原因。近年來,我國人民結(jié)直腸癌的發(fā)生率呈現(xiàn)升高趨勢。癌癥的表觀基因組表現(xiàn)為全局性的DNA甲基化的缺失和局部超甲基化。越來越多的實驗證明,特異性的長鏈非編碼RNA可以經(jīng)過和染色質(zhì)修飾復合體的相互作用,進而改變?nèi)旧|(zhì)的DNA甲基化狀態(tài)來調(diào)控基因的表達,是重要的基因表達調(diào)控元素,與腫瘤的發(fā)生發(fā)展密切相關(guān)。但關(guān)于長鏈非編碼RNA在結(jié)直腸癌中的研究卻只是冰山一角,進一步研究這其中的分子機制將很有必要。另外,不同的癌細胞所處的分化階段不同,關(guān)于不同分化程度的癌細胞之間在轉(zhuǎn)錄組學和表觀遺傳組學上的差異性的研究卻很少。本研究對12個不同分化程度(高分化、中分化,低分化)的結(jié)直腸癌組織樣本以及3個正常的結(jié)直腸組織樣本進行MeDIP-seq以及RNA-seq測序,并對測序數(shù)據(jù)分別進行質(zhì)量控制、比對、組裝、差異及功能富集分析、加權(quán)基因共表達和共甲基化網(wǎng)絡(luò)分析等,通過將癌癥的轉(zhuǎn)錄組學和DNA甲基化組測序數(shù)據(jù)進行聯(lián)合分析,以揭示不同分化程度的結(jié)直腸癌組織中差異表達的長鏈非編碼RNA與其靶基因的差異甲基化狀態(tài)之間的關(guān)系。通過本研究,我們識別了 1095個新的長鏈非編碼RNA轉(zhuǎn)錄本;篩選出了不同分化程度的結(jié)直腸癌組織與正常結(jié)直腸組織相比差異表達的116個長鏈非編碼RNA、1656個蛋白編碼基因和3994個差異DNA甲基化的位點。其中差異表達的長鏈非編碼RNA在GO Biological Process層面主要富集在消化道以及肺的形態(tài)發(fā)生中,差異表達的蛋白質(zhì)基因主要富集在兩種與癌癥侵襲、發(fā)生有關(guān)的信號通路中,即AGE-RAGE信號傳導通路以及Wnt信號傳導通路。與差異DNA甲基化片段所關(guān)聯(lián)的基因大部分都有和結(jié)直腸癌相關(guān)的報道。我們還識別出2個與結(jié)直腸癌顯著相關(guān)的加權(quán)基因共表達網(wǎng)絡(luò)(文中分別稱為green-yellow模塊和red模塊),其中g(shù)reen-yellow模塊與結(jié)直腸癌正相關(guān),而red模塊與結(jié)直腸癌負相關(guān)。另外我們找到3個差異表達長鏈非編碼RNA(分別是 RP11-288I21.1,RP11-35609.1,RP11-74M11.2),其所對應(yīng)的 3 個潛在靶基因(CLCNKA,TTC6,RNPS1P1)也是差異表達的,而且其靶基因的啟動子區(qū)域發(fā)生了差異DNA甲基化。我們的結(jié)果顯示,癌癥組樣本和正常組樣本之間表現(xiàn)出了明顯的差異性,但中分化癌癥組與正常組之間的差異性并非如我們所預想的介于高分化癌癥組和低分化癌癥組之間,這可能提示著,癌細胞的分化狀態(tài)與基因表達的改變之間并無直接的關(guān)系。另外結(jié)直腸癌患者與正常個體相比,其基因組發(fā)生了廣泛的DNA甲基化的缺失,這與之前的很多報道都是一致的。結(jié)直腸癌的表達譜和甲基化譜聯(lián)合分析顯示,長鏈非編碼RNA及其靶基因同時差異表達的結(jié)果有很多,而其靶基因的啟動子區(qū)域卻鮮少呈現(xiàn)出差異DNA甲基化的狀態(tài),這可能提示著,蛋白編碼基因啟動子區(qū)域錯誤的DNA甲基化并非結(jié)直腸癌細胞中異常表觀基因組修飾的關(guān)鍵特征。
[Abstract]:Colorectal cancer is one of the most common malignant tumors in the digestive tract. It is the fourth major cause of cancer death after lung cancer, gastric cancer and liver cancer. In recent years, the incidence of colorectal cancer in our country is increasing. The epigenetic genome of cancer is the loss of global DNA methylation and local hypermethylation. More and more experiments have proved that The specific long chain non coding RNA can interact with chromatin modified complex, and then change the DNA methylation status of chromatin to regulate gene expression. It is an important regulatory element of gene expression, which is closely related to the development of tumor. However, the study of long chain noncoding RNA in colorectal cancer is only an ice mountain. It is necessary to further study the molecular mechanisms of this. In addition, the differentiation stages of different cancer cells are different. There are few studies on the differences in the transcriptional and epigenetic components between different differentiated cancer cells. This study is a direct study of 12 different degrees of differentiation (high differentiation, middle differentiation, and low differentiation). Colorectal cancer tissue samples and 3 normal colorectal tissue samples were carried out by MeDIP-seq and RNA-seq sequencing, and the quality control, comparison, assembly, difference and functional enrichment analysis, weighted gene co expression and co methylation network analysis were performed on the sequencing data, by combining the transcriptional and DNA methylation data of the carcinoma. In this study, 1095 new long chain non coded RNA transcripts were identified, and 1095 colorectal cancer tissues with different differentiation range and normal colorectal tissues were screened by this study. Compared with 116 long chain non coding RNA, 1656 protein coding genes and 3994 different DNA methylation sites, the differentially expressed long chain non coding RNA was mainly enriched in the digestive tract and lung morphogenesis at the GO Biological Process level, and the differentially expressed protein genes were mainly enriched in two species and cancer invasion, The AGE-RAGE signal transduction pathway and the Wnt signal transduction pathway occur in the related signaling pathways. Most of the genes associated with differential DNA methylation fragments are related to colorectal cancer. We also identified 2 weighted gene co expression networks associated with colorectal cancer, which are called green-yellow module and R, respectively. Ed module), in which the green-yellow module is positively related to colorectal cancer, and the red module is negatively related to colorectal cancer. In addition, we find 3 differentially expressed long chain non coded RNA (RP11-288I21.1, RP11-35609.1, RP11-74M11.2), and the corresponding 3 potential target genes (CLCNKA, TTC6, RNPS1P1) are also differentially expressed, and their target genes are also expressed. The difference between the cancer group and the normal group showed a distinct difference between the cancer group and the normal group, but the difference between the differentiated cancer group and the normal group was not as between the highly differentiated cancer group and the low differentiated cancer group, which may suggest that the cancer cells are DNA. There is no direct relationship between the differentiation state and the changes in gene expression. In addition, colorectal cancer patients have extensive DNA methylation loss compared with normal individuals, which are consistent with many previous reports. Colorectal cancer expression and methylation analysis show that long chain non coded RNA and its target gene are identical. There are a lot of differences in time difference expression, but few of the promoter regions of the target gene show a state of differential DNA methylation, which may suggest that DNA methylation in the promoter region of the protein coding gene is not the key feature of abnormal epigenetic modification in colorectal cancer cells.

【學位授予單位】：南方醫(yī)科大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：R735.34
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本文編號：1867289