miR-18a调控胰腺祖细胞的增殖及其作用机制的研究

发布时间：2018-05-22 07:53

本文选题：miR-18a增殖 + 胰腺祖细胞　；参考：《东北林业大学》2015年硕士论文

【摘要】：糖尿病是由于胰岛B细胞破坏或胰岛素抵抗导致的胰岛素相对或绝对缺乏而引起,十分具有前景的治疗糖尿病的策略是通过胰腺干／祖细胞、胚胎干细胞、骨髓干细胞、脐血干细胞等定向诱导分化为胰岛p细胞,或者通过药物的作用胰岛p细胞的再生。目前,干细胞治疗糖尿病方面已经取得一定进展,但仍需进一步研究干／祖细胞增殖、分化和发育机制,才能获得更高效治疗效果。另外,研究表明胰腺癌发病率呈逐年上升趋势,其早期症状不明显,至今尚无有效的早期诊断方法,而且胰腺癌侵袭性强,恶性程度高,手术切除率低,预后极差,死亡率接近100%,因此研究胰腺癌细胞的增殖、侵袭等机制极为重要,为胰腺癌的早期诊断及治疗提供理论基础。microRNA (miRNA)是一类重要的小分子RNA,其在转录后阶段调控靶标基因的表达,识别miRNA的靶标基因是认识其调节功能的关键。在胰腺发育早期阶段,低水平Ptf1a促进胰腺祖细胞向内分泌方向分化,相反,高水平Ptf1a促进胰腺祖细胞向外分泌方向分化。研究表明,Ptf1a是miR-18a的直接靶基因,miR-18a通过调控Ptf1a的表达调控胰腺祖细胞的命运。此外,研究表明miR-18a在结肠癌细胞系中,miR-18a和miR-17-92的其他成员作用相反,尤其是和miR-19的作用相反,是作为抑制细胞增殖的miRNA发挥作用的。在miR-17-92成员中,miR-18a是唯一一个在形成成熟IniRNA过程中需要hnRNPA1处理的miRNA。miR-17-92的末端折叠结构也降低了miR-18a在形成成熟miRNA的过程中的编辑效率。miR-18a可能是作为一个平衡miR-17-92家族促进癌症发生的作用而存在的。然而关于miR-18a调控胰腺祖细胞和胰腺癌细胞的增殖的作用还没有相关报道。本课题通过在分离的胰腺祖细胞过表达miR-18a,发现可以明显抑制胰腺祖细胞的增殖,抑制PI3K/AKT信号通路和ERK信号通路,但后者作用并不明显。通过靶基因的筛选、鉴定和功能研究,发现CTGF、NEDD9、IGF1和CDK19是miR-18a的靶基因,但只有干涉CTGF、NEDD9和CDK19才会抑制胰腺祖细胞的增殖,同时影响PI3K/AKT和ERK信号通路。miR-18a通过调控CTGF、NEDD9和CDK19而调控胰腺祖细胞的增殖。对于胰腺癌细胞系BXPC3而不是PANC-1,过表达miR-18a明显抑制癌细胞的增殖及ERK的信号通路,但抑制内源性miR-18a的表达则无明显作用。干涉miR-18a其中一个靶基因NEDD9抑制胰腺癌细胞系BXPC3的增殖,对PANC-1细胞系无作用,同时对ERK信号通路影响不大。在胰腺癌细胞系中,miRNA-18a的作用有待进一步的研究。
[Abstract]:Diabetes is caused by the relative or absolute deficiency of insulin caused by the destruction of islet B cells or insulin resistance, and a promising strategy for the treatment of diabetes is through pancreatic stem / progenitor cells, embryonic stem cells, bone marrow stem cells. Umbilical cord blood stem cells were induced to differentiate into islet p cells or to regenerate islet p cells by drugs. At present, some progress has been made in the treatment of diabetes by stem cells, but the mechanism of stem / progenitor cell proliferation, differentiation and development need to be further studied in order to obtain a more effective therapeutic effect. In addition, studies show that the incidence of pancreatic cancer is increasing year by year, its early symptoms are not obvious, so far there is no effective early diagnosis method, and pancreatic cancer has strong invasion, high degree of malignancy, low resection rate and poor prognosis. The mortality rate is close to 100%, so it is very important to study the mechanism of pancreatic cancer cell proliferation and invasion, which provides the theoretical basis for early diagnosis and treatment of pancreatic cancer. MicroRNA miRNAs are a kind of important small molecule RNAs, which regulate the expression of target gene in posttranscriptional stage. Recognizing the target gene of miRNA is the key to understand its regulatory function. At the early stage of pancreatic development, low level Ptf1a promoted pancreatic progenitor cells to differentiate into endocrine direction, whereas high level Ptf1a promoted pancreatic progenitor cells to differentiate into exocrine direction. It is suggested that Ptf1a is a direct target gene of miR-18a, which regulates the fate of pancreatic progenitor cells by regulating the expression of Ptf1a. In addition, it has been shown that miR-18a plays an opposite role in colon cancer cell lines, especially miRNA, which inhibits the proliferation of human colon cancer cells, especially miR-19. Among miR-17-92 members, miR-18a is the only miRNA.miR-17-92 terminal folding structure that requires hnRNPA1 processing in the process of forming a mature IniRNA, which also reduces the editing efficiency of miR-18a during the formation of a mature miRNA. MiR-18a may act as a balanced miR-17-92 family to promote cancer. The effect of the occurrence of the disease. However, the role of miR-18a in regulating the proliferation of pancreatic progenitor cells and pancreatic cancer cells has not been reported. By overexpression of miR-18a in isolated pancreatic progenitor cells, we found that miR-18a could significantly inhibit the proliferation of pancreatic progenitor cells, PI3K/AKT signaling pathway and ERK signaling pathway, but the latter had no obvious effect. Through screening, identification and functional study of target genes, it was found that CTGF- NEDD9 IGF1 and CDK19 were target genes of miR-18a, but only interference with CTGF- NEDD9 and CDK19 could inhibit the proliferation of pancreatic progenitor cells. Both PI3K/AKT and ERK signaling pathway. MiR-18a regulated the proliferation of pancreatic progenitor cells by regulating CTGFN NEDD9 and CDK19. In pancreatic cancer cell line BXPC3 but not PANC-1, overexpression of miR-18a significantly inhibited the proliferation of cancer cells and the signal pathway of ERK, but did not inhibit the expression of endogenous miR-18a. NEDD9, one of the target genes of interference miR-18a, inhibited the proliferation of pancreatic cancer cell line BXPC3, but had no effect on PANC-1 cell line, but had little effect on ERK signaling pathway. The role of miRNA-18 a in pancreatic cancer cell line needs further study.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R735.9

【相似文献】