Pancreatic ductal adenocarcinoma (PDAC) accounts for about 90% of all pancreatic cancer cases. Five-year survival rates have remained below 12% since the 1970s, in part due to the difficulty in detection prior to metastasis (migration and invasion into neighboring organs and glands). Mechanical memory is a concept that has emerged over the past decade that may provide a path toward understanding how invading PDAC cells “remember” the mechanical properties of their diseased (“stiff”, elastic modulus, E ≈ 10 kPa) microenvironment even while invading a healthy (“soft”, E ≈ 1 kPa) microenvironment. Here, we investigated the role of mechanical priming by culturing a dilute suspension of PDAC (FG) cells within a 3D, rheologically tunable microgel platform from hydrogels with tunable mechanical properties. We conducted a suite of acute (short-term) priming studies where we cultured PDAC cells in either a soft (E ≈ 1 kPa) or stiff (E ≈ 10 kPa) environment for 6 h, then removed and placed them into a new soft or stiff 3D environment for another 18 h. Following these steps, we conducted RNA-seq analyses to quantify gene expression. Initial priming in the 3D culture showed persistent gene expression for the duration of the study, regardless of the subsequent environments (stiff or soft). Stiff 3D culture was associated with the downregulation of tumor suppressors (LATS1, BCAR3, CDKN2C), as well as the upregulation of cancer-associated genes (RAC3). Immunofluorescence staining (BCAR3, RAC3) further supported the persistence of this cellular response, with BCAR3 upregulated in soft culture and RAC3 upregulated in stiff-primed culture. Stiff-primed genes were stratified against patient data found in The Cancer Genome Atlas (TCGA). Upregulated genes in stiff-primed 3D culture were associated with decreased survival in patient data, suggesting a link between patient survival and mechanical priming.

中文翻译：

---

在软质和硬质 3D 微凝胶培养之间切换的胰腺导管腺癌 (PDAC) 中维持生存相关细胞反应

胰腺导管腺癌 (PDAC) 约占所有胰腺癌病例的 90%。自 20 世纪 70 年代以来，五年生存率一直低于 12%，部分原因是在转移（迁移和侵入邻近器官和腺体）之前难以检测到。机械记忆是过去十年中出现的一个概念，它可能为理解入侵的 PDAC 细胞如何“记住”患病微环境的机械特性（“僵硬”、弹性模量、E ≈ 10 kPa）提供一条途径，即使在入侵健康（“软”，E ≈ 1 kPa）微环境。在这里，我们通过在具有可调机械性能的水凝胶的 3D、流变学可调微凝胶平台中培养 PDAC (FG) 细胞的稀悬浮液来研究机械引发的作用。我们进行了一系列急性（短期）启动研究，将 PDAC 细胞在柔软（E ≈ 1 kPa）或坚硬（E ≈ 10 kPa）环境中培养 6 小时，然后将其取出并放入新的软环境中。或僵硬的 3D 环境再持续 18 小时。按照这些步骤，我们进行了 RNA-seq 分析来量化基因表达。 3D 培养中的初始启动显示出在研究期间持续的基因表达，无论随后的环境（坚硬或柔软）如何。僵硬的 3D 培养物与肿瘤抑制因子（ LATS1、BCAR3、CDKN2C ）的下调以及癌症相关基因（RAC3）的上调有关。免疫荧光染色（BCAR3、RAC3）进一步支持了这种细胞反应的持续性，BCAR3 在软培养物中上调，RAC3 在硬引发培养物中上调。根据癌症基因组图谱 (TCGA) 中发现的患者数据对刚性启动基因进行分层。硬启动 3D 培养物中基因上调与患者数据中的生存率降低相关，这表明患者生存与机械启动之间存在联系。