Fluid shear stress enhances the metastatic potential and rapidly alters metabolism of circulating tumor cells

Abstract Background and Purpose: Circulating tumor cells (CTCs) are exposed to mechanical and biochemical stresses including fluid shear stress (FSS), due to blood flow, and oxidative distress, from a lack of matrix attachment. 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, here 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 cells to FSS prior to injection into the tail-vein of NCG mice. We then monitored metastasis formation by weekly bioluminescence imaging. We also examined whether FSS exposure altered the ability of PC-3 and MDA-MB-231 cells to invade through a collagen I matrix, as well as their ability to survive/proliferate under anchorage-independent conditions. We conducted GC/LC-MS metabolomic profiling immediately after FSS exposure. To investigate oxidative burden on FSS exposed cells, we used dihydroethidium (10µM, 30 minutes) to measure general ROS production and a lipid peroxide sensor (5µM, 20 minutes). Results: We found that FSS exposure shortens the time for metastasis formation by 20% (median of 42 vs 52.5 days metastasis free; p=0.0222, log-rank). For both PC-3 and MDA-MB-231 cells we found that FSS exposure leads to ~2x increase in invasion through collagen matrix, and that increase depends on RhoA. 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 a decrease in the metabolites that feed the folate cycle. We blocked glycolysis in PC-3 and MDA-MB-231 cells with 2-deoxyglucose (25mM, 2 hours) 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. FSS rapidly alters cellular metabolism in a manner that 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. This abstract is being presented as a short talk in the scientific program. A full abstract is available in the Short Talks from Proffered Abstracts section (PR006) of the Conference Proceedings. Citation Format: Devon L. Moose, Amanda N. Pope, Marion Vanneste, Patrick Breheny, Eric B. Taylor, Michael D. HenryDevon L. Moose, Amanda N. Pope, Marion Vanneste, Patrick Breheny, Eric B. Taylor, Michael D. Henry. Fluid shear stress enhances the metastatic potential and rapidly alters metabolism of circulating tumor cells [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B047.