Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada.
Am J Physiol Cell Physiol. 2024 Oct 1;327(4):C959-C978. doi: 10.1152/ajpcell.00452.2024. Epub 2024 Aug 26.
The tumor microenvironment is complex and dynamic, characterized by poor vascularization, limited nutrient availability, hypoxia, and an acidic pH. This environment plays a critical role in driving cancer progression. However, standard cell culture conditions used to study cancer cell biology in vitro fail to replicate the in vivo environment of tumors. Recently, "physiological" cell culture media that closely resemble human plasma have been developed (e.g., Plasmax, HPLM), along with more frequent adoption of physiological oxygen conditions (1%-8% O). Nonetheless, further refinement of tumor-specific culture conditions may be needed. In this study, we describe the development of a tumor microenvironment medium (TMEM) based on murine pancreatic ductal adenocarcinoma (PDAC) tumor interstitial fluid. Using RNA-sequencing, we show that murine PDAC cells (KPCY) cultured in tumor-like conditions (TMEM, pH 7.0, 1.5% O) exhibit profound differences in gene expression compared with plasma-like conditions (mouse plasma medium, pH 7.4, 5% O). Specifically, the expression of genes and pathways associated with cell migration, biosynthesis, angiogenesis, and epithelial-to-mesenchymal transition were altered, suggesting tumor-like conditions promote metastatic phenotypes and metabolic remodeling. Using functional assays to validate RNA-seq data, we confirmed increased motility at 1.5% O/TMEM, despite reduced cell proliferation. Moreover, a hallmark shift to glycolytic metabolism was identified via measurement of glucose uptake/lactate production and mitochondrial respiration. Taken together, these findings demonstrate that growth in 1.5% O/TMEM alters several biological responses in ways relevant to cancer biology, and more closely models hallmark cancerous phenotypes in culture. This highlights the importance of establishing tumor microenvironment-like conditions in standard cancer research. Standard cell culture conditions do not replicate the complex tumor microenvironment experienced by cells in vivo. Although currently available plasma-like media are superior to traditional supraphysiological media, they fail to model tumor-like conditions. Using RNA-seq analysis and functional metabolic and migratory assays, we show that tumor microenvironment medium (TMEM), used with representative tumor hypoxia, better models cancerous phenotypes in culture. This emphasizes the critical importance of accurately modeling the tumor microenvironment in cancer research.
肿瘤微环境复杂且动态，其特点为血管生成不良、营养有限、缺氧和酸性 pH 值。这种环境在推动癌症进展方面起着关键作用。然而，用于体外研究癌症细胞生物学的标准细胞培养条件无法复制肿瘤的体内环境。最近，已经开发出了更接近人类血浆的“生理”细胞培养基（例如 Plasmax、HPLM），并更频繁地采用生理氧条件（1%-8% O）。尽管如此，可能需要进一步细化肿瘤特异性培养条件。在这项研究中，我们描述了一种基于小鼠胰腺导管腺癌（PDAC）肿瘤间质液的肿瘤微环境培养基（TMEM）的开发。通过 RNA 测序，我们表明，在类似肿瘤的条件（TMEM，pH 值 7.0，1.5% O）下培养的小鼠 PDAC 细胞（KPCY）与类似血浆的条件（小鼠血浆培养基，pH 值 7.4，5% O）相比，在基因表达上存在显著差异。具体而言，与细胞迁移、生物合成、血管生成和上皮间质转化相关的基因和途径的表达发生改变，表明类似肿瘤的条件促进了转移表型和代谢重塑。通过功能测定验证 RNA-seq 数据，我们证实尽管细胞增殖减少，但在 1.5% O/TMEM 下的迁移能力增加。此外，通过测量葡萄糖摄取/乳酸产生和线粒体呼吸，确定了标志性的糖酵解代谢转变。总之，这些发现表明，在 1.5% O/TMEM 中生长以方式改变了几种与癌症生物学相关的生物学反应，并更紧密地模拟了培养中的标志性癌症表型。这凸显了在标准癌症研究中建立肿瘤微环境样条件的重要性。标准细胞培养条件无法复制细胞在体内经历的复杂肿瘤微环境。尽管目前可用的类似血浆的培养基优于传统的超生理培养基，但它们无法模拟类似肿瘤的条件。通过 RNA-seq 分析和功能代谢及迁移测定，我们表明，使用代表性肿瘤缺氧的肿瘤微环境培养基（TMEM），可以更好地在培养中模拟癌症表型。这强调了在癌症研究中准确模拟肿瘤微环境的至关重要性。
