Najera Julian, Chen Hao, Batista Bianca, Ketchum Frank, Ali Aktar, Zorlutuna Pinar, Howard Scott, Datta Meenal
Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN, USA.
Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN, USA.
bioRxiv. 2025 May 30:2025.05.28.656717. doi: 10.1101/2025.05.28.656717.
The breast peritumor microenvironment (pTME) is increasingly recognized as a mediator of breast cancer progression and treatment resistance. However, if and how growth-induced tumor compressive forces (i.e., solid stresses) influence the breast pTME remains unclear. Here we show using instant fluorescence lifetime imaging microscopy (FLIM)-a frequency-domain FLIM system capable of simultaneous image acquisition and instantaneous data processing-that breast tumor-mimicking compression promotes metabolic changes in stromal cells found in the breast pTME. Namely, compression shifts NIH3T3 fibroblasts and differentiated 3T3-L1 (d3T3-L1) adipocytes toward a more glycolytic state, while it promotes increased oxidative phosphorylation in 3T3-L1 undifferentiated adipocytes. The gold-standard Seahorse extracellular flux assay fails to capture these changes, underscoring the superior sensitivity of instant FLIM in detecting metabolic shifts. We validate these phenotypic findings at the transcriptomic level via RNA sequencing, confirming that compressed fibroblasts downregulate oxidative phosphorylation and upregulate glycolysis compared to uncompressed controls. We further demonstrate that compression induces mitochondrial dysregulation in undifferentiated adipocytes, driven in part by upregulated mitophagy and disrupted fusion dynamics. Finally, we confirm that these stromal cell types recapitulate these distinct metabolic states in human breast cancer patient samples, consistent with our findings. By elucidating mechano-metabolic interactions occurring at the tumor-host interface, these results will inform the development of innovative mechano-metabolic reprogramming treatment strategies to improve breast cancer patient survival.
乳腺肿瘤周围微环境（pTME）日益被认为是乳腺癌进展和治疗耐药性的介导因素。然而，生长诱导的肿瘤压缩力（即固体应力）是否以及如何影响乳腺pTME仍不清楚。在这里，我们使用即时荧光寿命成像显微镜（FLIM）——一种能够同时进行图像采集和即时数据处理的频域FLIM系统——表明模拟乳腺肿瘤的压缩促进了乳腺pTME中基质细胞的代谢变化。具体而言，压缩使NIH3T3成纤维细胞和分化的3T3-L1（d3T3-L1）脂肪细胞向更糖酵解的状态转变，而它促进了3T3-L1未分化脂肪细胞中氧化磷酸化的增加。金标准的海马细胞外通量分析未能捕捉到这些变化，突出了即时FLIM在检测代谢转变方面的卓越灵敏度。我们通过RNA测序在转录组水平验证了这些表型发现，证实与未压缩的对照相比，压缩的成纤维细胞下调了氧化磷酸化并上调了糖酵解。我们进一步证明，压缩在未分化脂肪细胞中诱导线粒体失调，部分原因是线粒体自噬上调和融合动力学破坏。最后，我们证实这些基质细胞类型在人类乳腺癌患者样本中重现了这些不同的代谢状态，与我们的发现一致。通过阐明肿瘤-宿主界面发生的机械-代谢相互作用，这些结果将为开发创新的机械-代谢重编程治疗策略提供信息，以提高乳腺癌患者的生存率。
