PO.TB07.03 · 肿瘤生物学
探究miR-27a-3p在结直肠癌干细胞WNT信号通路中的作用
Investigating the role of miR-27a-3p in the WNT signaling pathway in colorectal cancer stem cells
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
癌症干细胞（CSC）的过度增殖驱动结直肠癌（CRC）的发生与生长，但其分子机制尚不明确。CSC的功能表型特征包括信号通路的失调。CRC CSC尤其以其高WNT信号活性为特征，特别是那些由干细胞标志物富含亮氨酸重复序列的G蛋白偶联受体5（LGR5）定义的细胞。越来越多的科学证据表明，参与转录后基因表达调控的miRNA在维持CSC表型中发挥重要作用。然而，确切机制仍不清楚。我们的目标是研究miRNA如何促成CRC的干细胞起源。我的初步实验使用HT-29 CRC细胞和NanoString分析，以鉴定在FACS分选的CSC中富集的miRNA。我发现miR-27a-3p在LGR5+ CSC中相较于LGR5-细胞被差异性上调。对现有深度测序数据的分析也显示，经典的miR-27a-3p是人类CRC中表达最高的异构体，并在结肠腺瘤-癌进展过程中显著上调。已有研究表明miR-27a-3p：i）利用其他CSC标志物和方法在人类CRC的CSC中富集；ii）在多种癌症中激活或抑制WNT信号活性；iii）在多种癌症中增强化疗耐药性。miR-27a-3p在CRC中调控WNT信号的确切机制尚未阐明。假说：miR-27a-3p在CRC及LGR5+干细胞亚群中富集；miR-27a-3p通过抑制WNT拮抗剂靶点促进WNT信号的表达。在HT-29稳定慢病毒过表达细胞系中观察到细胞增殖显著增加，以及WNT靶基因LGR、cMYC、cyclin D1、MET和CD44的mRNA增加。在HCT116稳定慢病毒敲低的CRC细胞系中观察到LGR5、cMYC、cyclin D1和MET的减少。我的研究结果表明，miR-27a-3p通过靶向影响beta-catenin稳定性和表达的WNT拮抗靶点，在CRC细胞系中调控WNT信号。
查看英文原文 English abstract
Cancer stem cell (CSC) overpopulation drives colorectal cancer (CRC) development and growth, but molecular mechanisms are unclear. CSCs functional phenotypic characteristics include signaling pathway dysregulation. CRC CSCs, in particular, are defined by their high WNT signaling activity, particularly those defined by the stem cell maker leucine-rich-repeat containing G protein-coupled receptor 5 (LGR5). A growing body of scientific evidence indicates that miRNAs, involved in post-transcriptional gene expression, play an important role in maintaining the CSC phenotype. However, the exact mechanism is still unknown. Our goal is to investigate how miRNAs contribute to the SC origin of CRC. My preliminary experiments used HT-29 CRC cells and NanoString profiling to identify miRNAs enriched in FACS-isolated CSCs. I discovered that miR-27a-3p is differentially upregulated in LGR5+ CSCs versus LGR5- cells. Analysis of available deep sequencing data also shows that the canonical miR-27a-3p is the highest expressed isoform in human CRC and is significantly upregulated during the colonic adenoma-carcinoma progression. miR-27a-3p has been shown to: i) be enriched in human CSCs in CRC utilizing other CSCs markers and methods; ii) activate or repress WNT signaling activity in various cancers; iii) increase chemoresistance in various cancers. The exact mechanism by which miR-27a-3p functions in CRC to regulate WNT signaling has not been elucidated. Hypothesis : miR-27a-3p is enriched in CRC and the LGR5+ SC subpopulation; miR-27a-3p promotes WNT signaling expression through repression of WNT antagonist targets. A significant increase in cellular proliferation was seen in the HT-29 stable lentiviral overexpressing cell line, and an increase in the WNT target genes mRNA of LGR, cMYC, cyclin D1, MET, and CD44. Decreases in LGR5, cMYC, cyclin D1, and MET were seen in the HCT116 stable lentiviral knockdown CRC cell line. My findings show that miR-27a-3p modulates WNT signaling in CRC cell lines by targeting WNT antagonistic targets that affect the stability and expression of beta-catenin.
利益披露 Disclosure
M. A. Lausten, None..
V. A. Stark, None..
C. O. B. Facey, None..
L. M. Opdenaker, None..
B. M. Boman, None.