Mapping functional to morphological variation reveals the basis of regional extracellular matrix subversion and nerve invasion in pancreatic cancer [RNA-Seq2]. Mapping functional to morphological variation reveals the basis of regional extracellular matrix subversion and nerve invasion in pancreatic cancer [RNA-Seq2]

Intratumor morphological heterogeneity of pancreatic ductal adenocarcinoma (PDAC) predicts clinical outcomes but is only partially understood at the molecular level. To elucidate the gene expression programs underpinning intratumor morphological variation in PDAC, we investigated and deconvoluted at single cell level the molecular profiles of histologically distinct clusters of PDAC cells. We identified three major morphological and functional variants that co-exist in varying proportions in all PDACs, display limited genetic diversity, and are associated with a distinct organization of the extracellular matrix: a glandular variant with classical ductal features; a transitional variant displaying abortive ductal structures and mixed endodermal and myofibroblast-like gene expression; and a poorly differentiated variant lacking ductal features and basement membrane, and showing neuronal lineage priming. Ex vivo and in vitro evidence supports the occurrence of dynamic transitions among these variants in part influenced by extracellular matrix composition and stiffness and associated with local, specifically neural, invasion. Overall design: Total RNA from primary human pancreatic ductal adenocarcinoma cells was processed for multiparallel sequencing. Experiments were carried out in PATC69 cell line cultured on collagen-coated plates of 12kPa and 1kPa stiffness (2 replicates each).

胰腺导管腺癌（pancreatic ductal adenocarcinoma, PDAC）的肿瘤内形态异质性可预测临床结局，但目前对其分子机制的阐释仍不够充分。为阐明驱动PDAC肿瘤内形态变异的基因表达程序，我们在单细胞层面解析了组织学特征各异的PDAC细胞簇的分子谱。
我们鉴定出三种主要的形态与功能变异亚型，它们在所有PDAC肿瘤中以不同比例共存，遗传多样性有限，且与细胞外基质（extracellular matrix, ECM）的独特组织模式相关：其一为腺体亚型，具有典型的导管上皮特征；其二为过渡亚型，表现为发育不全的导管结构，同时兼具内胚层与肌成纤维细胞样基因表达谱；其三为低分化亚型，无导管上皮特征且缺乏基底膜，同时显示神经谱系预激活。
离体（ex vivo）与体外（in vitro）实验证据表明，这些亚型间可发生动态转化，该过程部分受细胞外基质组成与刚度的调控，并与局部侵袭，尤其是神经侵袭密切相关。
实验设计概况：我们对原代人胰腺导管腺癌细胞的总RNA进行了多平行测序分析。实验采用PATC69细胞系，分别在刚度为12kPa与1kPa的胶原蛋白包被培养板中培养，每组设置2个生物学重复。