Instituto de Biotecnología Ambiental y Salud (INBIAS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, Argentina.
Photochem Photobiol. 2020 Jul;96(4):897-905. doi: 10.1111/php.13220. Epub 2020 Apr 11.
Tumor microenvironment (TME) is a dynamic ecosystem where fibroblasts are recruited in order to provide a niche to support growth and, in some extent, to promote therapeutic resistance. However, the role of fibroblasts in stimulating or impairing photodynamic therapy (PDT) outcome has not yet been fully addressed. PDT is based on interactions between light, oxygen and photosensitizer, leading to phototoxic reactions that culminate in cell death. In this study, we demonstrated the consequences of a hypoxic stromal phenotype on tumor mass for exploring PDT response. We mimicked TME complexity implementing colon cancer cells and fibroblasts 3D cultures called spheroids. Using hypoxia reporting lines, we verified that homotypic spheroids exhibited a size-dependent transcriptional HIF-1 activity. When cocultured, fibroblasts were localized in the hypoxic core. In homotypic stromal spheroids, the distribution of the endogenous photosensitizer PpIX was homogeneous while decreased in hypoxic areas of tumor 3D cultures. When monocultured, fibroblasts were more efficient to produce PpIX from its prodrug Me-ALA. Interestingly, the cross talk between cancer cells and fibroblasts attenuated PpIX accumulation and conferred tumor PDT resistance when compared to homotypic 3D cultures. Overall, our data suggest that stroma and tumor act in an integrated, reciprocal fashion which could ultimately influence on therapeutic response.
肿瘤微环境（TME）是一个动态的生态系统，其中招募成纤维细胞以提供支持生长的小生境，并在某种程度上促进治疗抵抗。然而，成纤维细胞在刺激或损害光动力疗法（PDT）效果方面的作用尚未得到充分解决。PDT 基于光、氧和光敏剂之间的相互作用，导致光毒性反应，最终导致细胞死亡。在这项研究中，我们研究了基质缺氧表型对肿瘤质量的影响，以探索 PDT 反应。我们通过实施称为球体的结肠癌细胞和成纤维细胞 3D 培养物来模拟 TME 的复杂性。使用缺氧报告系，我们验证了同型球体表现出大小依赖性转录因子 HIF-1 活性。当共培养时，成纤维细胞定位于缺氧核心。在同型基质球体中，内源性光敏剂 PpIX 的分布是均匀的，而在肿瘤 3D 培养物的缺氧区域则减少。当单独培养时，成纤维细胞从其前药 Me-ALA 产生 PpIX 的效率更高。有趣的是，与同型 3D 培养物相比，癌细胞和成纤维细胞之间的串扰会降低 PpIX 的积累并赋予肿瘤 PDT 抗性。总的来说，我们的数据表明，基质和肿瘤以一种综合的、相互的方式发挥作用，这可能最终影响治疗反应。
