High Shear Stresses under Exercise Condition Destroy Circulating Tumor Cells in a Microfluidic System.
Level 5 - mechanism / opinion, no new human data
In vitro microfluidic laboratory experiment without human or animal subjects
PubMed 28054593 · doi:10.1038/srep39975
What was done
Researchers developed an in vitro microfluidic circulatory system to test the effects of resting arterial shear stress (15 dynes/cm²) versus intensive exercise-level shear stress (60 dynes/cm²) on circulating tumor cells (CTCs). The test included breast cancer cells with varying metastatic potential, as well as ovarian, lung, and leukemic cell lines. CTC necrosis during circulation and subsequent apoptosis during 16–24 hours of post-circulation incubation were assessed.
What was found
High shear stress of 60 dynes/cm² killed more CTCs than 15 dynes/cm², causing necrosis in over 90% of CTCs within the first 4 hours of circulation. The CTCs surviving the initial 4-hour circulation underwent apoptosis during 16–24 hours of post-circulation incubation. Prolonged high shear stress reduced the viability of highly metastatic and drug-resistant breast cancer cells, while exhibiting much less damaging effects on leukemic cells used to model white blood cells.
Why it matters
This study provides a biophysical mechanism demonstrating that exercise-level fluid shear stress can directly destroy circulating cancer cells, supporting a theoretical basis for exercise in metastasis prevention.
Limits
This was an in vitro cell-line study in a microfluidic model, not an in vivo or human study. It did not assess whole-blood cellular interactions, vascular physiology, complex systemic clearance, or clinical metastasis outcomes.
Cited by
- supports Circulating tumor cells have mechanosensors on their surface and can undergo apoptosis in response to the mechanical shear stress and friction of blood flow during exercise.
- supports Engaging in physical activity reduces the risk of cancer recurrence and metastasis in individuals with circulating tumor cells.
- partial Hemodynamic shearing forces generated during vigorous exercise kill circulating tumor cells, which is associated with lower cancer recurrence and mortality.