Abstract 199: Fluid shear stress enhances metastatic potential and rapidly alters metabolism of circulating tumor cells
Authors: Moose Devon L. , Pope Amanda N. , Dykstra Marion , Taylor Eric B. , Breheny Patrick , Henry Michael D. 
Published: March 2024

Abstract
Background and Purpose: Circulating tumor cells (CTCs) are exposed to mechanical and biochemical stresses including fluid shear stress (FSS) and oxidative distress. Recently we have shown that viable CTCs actively resist destruction when exposed to FSS by a mechano-adaptive mechanism that depends on RhoA-actomyosin activity [PMID: 32187555]. Since the RhoA-actomyosin axis is implicated in other cellular behaviors that might contribute to metastasis; herein, we explored the hypothesis that exposure to FSS alters the biology of viable CTCs to promote metastatic colonization.
Methodology: To determine if exposure to FSS alters metastatic potential, we exposed PC-3 prostate and MDA-MB-231 breast cancer cells to FSS prior to injection into the tail-vein of NCG mice. We then monitored metastatic colonization by weekly bioluminescence imaging. Further, we examined if FSS exposure altered the invasive potential of PC-3 and MDA-MB-231 cells, as well as their ability to survive/proliferate under anchorage-independent conditions. We conducted GC/LC-MS metabolomic profiling and measured lactate production following FSS exposure. To investigate oxidative burden on FSS exposed cells, we used dihydroethidium to measure general ROS production and a lipid peroxide sensor.
Results: We found that FSS exposure shortens the time for metastatic colonization for both cell lines. We found that FSS exposure leads to approximately two-fold increase in invasion through collagen matrix, which, for PC-3 cells, is RhoA dependent. Moreover, FSS exposure resulted in increased proliferation (~25%) under anchorage independent conditions in both cell lines. Metabolomic profiling revealed that FSS exposure resulted increased glycolysis, reduced entry into the TCA cycle, and increased lactate levels. We blocked glycolysis in PC-3 and MDA-MB-231 cells with 2-deoxyglucose and found that this increased the fraction of cells destroyed by FSS ~20-30%. We also investigated redox stress and found that compared to cells held in suspension, those exposed to FSS demonstrate lower ROS burden. Interestingly, cells exposed to FSS exhibit lower levels of lipid peroxides in a manner that depends on RhoA.
Conclusion: Our findings demonstrate that brief pulses of FSS exposure can enhance metastatic potential, increase invasive and anchorage-independent proliferative capacity and rapidly alter metabolism. The phenotypic changes driven by exposure to FSS depend in part on RhoA activation but may also reflect other mechanisms by which cancer cells sense and respond to FSS. The rapid changes in metabolism may act to reduce oxidative distress while CTCs are in suspension. In summary, our data indicate that FSS exposure in the circulation not only represents a physical force that CTCs must overcome to survive, but it also provides instructive cues that may enhance the metastatic behavior of some CTCs.
Citation Format: Devon L. Moose, Amanda N. Pope, Marion Dykstra, Eric B. Taylor, Patrick Breheny, Michael D. Henry. Fluid shear stress enhances metastatic potential and rapidly alters metabolism of circulating tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 199.