https://blog.superhyydl.org/tags/%E8%B6%85%E7%BA%A7%E5%A2%9E%E5%BC%BA%E5%AD%90/Recent content in 超级增强子 on Superhyydl's BlogHugozh-cnTue, 01 Sep 2026 00:00:00 +0000https://blog.superhyydl.org/reading/3d-epigenomic-remodelling-mediated-by-foxa1-drives/Tue, 01 Sep 2026 00:00:00 +0000https://blog.superhyydl.org/reading/3d-epigenomic-remodelling-mediated-by-foxa1-drives/<h2 id="一句话亮点">一句话亮点</h2> <p>这篇《Cancer Letters》论文通过多组学整合分析，揭示了转录因子Foxa1作为“总指挥”，通过重塑超级增强子（SE）和三维基因组结构，协同激活耐药基因Rrm1和Cdadc1，驱动胰腺癌吉西他滨耐药；而临床期BET抑制剂AZD5153能拆解这一表观基因组“堡垒”，有效逆转耐药。</p> <h2 id="背景痛点">背景/痛点</h2> <p>吉西他滨是胰腺癌治疗近三十年的基石药物，但耐药问题几乎注定出现，导致治疗失败。已知的耐药机制——比如药物代谢改变、DNA修复增强——都是“点状”的零散发现。一个关键问题始终悬而未决：这些分散的耐药特征，背后是否存在一个更高层次的、系统性的调控枢纽？</p> <p>转录因子FOXA1作为先锋因子（Pioneer Factor）能结合紧密染色质并重塑其结构，在多种癌症中与不良预后相关。但它是否、以及如何在三维基因组层面组织起一个耐药“指挥部”，此前并不清楚。</p> <h2 id="推理链分步拆解">推理链分步拆解</h2> <h3 id="第一步建立模型锁定转录组嫌疑基因">第一步：建立模型，锁定转录组“嫌疑基因”</h3> <p>研究者首先建立了三对来自KPC小鼠模型的亲本（Pa）和吉西他滨耐药（GR）胰腺癌细胞系。耐药细胞IC50飙升了500倍以上，并且对吉西他滨诱导的G0/G1周期阻滞“无动于衷”。</p> <p>通过RNA-seq，他们画出了耐药细胞的转录组画像：851个基因差异表达，其中435个上调。重点在于，上调基因显著富集在NF-κB、p53、MAPK等“生存通路”上，而一些关键的耐药“老面孔”——如核苷酸还原酶Rrm1和胞苷脱氨酶Cdadc1——赫然在列。这一发现暗示，耐药可能由一个上游的“总开关”同时激活了这些下游效应分子。</p> <p>@方法论点评：利用同源亲本-耐药对进行组学比较，能有效过滤遗传背景噪音，直接捕捉耐药“获得”过程中发生的转录改变。</p> <p>接下来，他们自然会问：这些转录变化，是否反映在更上游的染色质层面？</p> <p><img alt="Fig. 1：Gene regulatory underpinnings of gemcitabine resistance in mouse pancreatic cancer cell lines. (A) Three pairs of parental and resistant cells were treated with the indicated concentrations of gemcitabine for 72 h, and cell viability was quantified via the SRB assay. (B) Histograms showing the percentages of cells in each cell cycle phase after treatment with DMSO (Ctrl) or 1 μM gemcitabine (Gem) for 72 h. (C) Ridgeline plot showing the results of gene set enrichment analysis (GSEA) of MSigDB hallmark pathways by comparing gemcitabine-resistant cells to parental cells that had not been exposed to gemcitabine. The color gradient depicts the normalized enrichment score (NES) range varying from dark red (increased in GR) to dark blue (decreased in GR). The x-axis represents the log2-fold change (FC) in gene expression between GRs and PAs determined by mRNA-seq. For cross-species GSEA, mouse and human homologue genes were mapped together on the basis of identical gene symbols via the R package biomaRt (v2.52.0). Only the mouse genes with detectable human homologues were included. (D) Representative GSEA enrichment plots are shown. TNFA signalling via NF-kB and the KRAS signalling pathways that are significantly enriched in GR cells (positive NES) are colored red in (C). MYC target V1 and mTORC1 signalling pathways that are significantly enriched in Pa cells (negative NES) are highlighted in blue in (C). Statistical significance was calculated by the nominal P value of the NES via an empirical gene set-based permutation test. NES, normalized enrichment score. (E) Dot plot depicting the hierarchical arrangement of differentially expressed genes (DEGs) identified between gemcitabine-resistant and parental cell lines. The DEGs are distinguished by various colors, which correlate with their FDR, whereas the diameter of each circle is indicative of log2(FC), where FC represents the fold change. The number of DEGs that were upregulated or downregulated between groups is shown in the plot. (F) Western blot analysis was conducted on Rrm1 and Cdadc1 proteins in 3 paired parental and gemcitabine-resistant cell lines. (G and H) Bar plot illustrating the top 20 KEGG pathways that are significantly enriched in either the upregulated (F, red) or downregulated (G, blue) genes. The pathways are ranked on the basis of a score derived from the negative logarithm base 10 of their respective P values. A polygonal chain in black delineates the gene count associated with each KEGG pathway. (I) The category netplot elucidates the intricate connections between DEGs and a select group of significantly enriched KEGG pathways, which are denoted in red text and symbolized by black dots. The diameter of each dot serves as a visual indicator of the gene count associated with each respective pathway. The DEGs are highlighted in different colors according to their fold change values. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)" loading="lazy" src="https://blog.superhyydl.org/images/reading/3d-epigenomic-remodelling-mediated-by-foxa1-drives/figure-01.png"></p>