Week 5

I spent the entire week at the World Congress of Biomechanics conference in Boston, MA. Since I wasn’t in the hospital I do not have any clinical experiences to share, but I will highlight some of the interesting points I learned at the conference:

• Cells spread more on stiffer substrates. This increases stress on the nucleus however.
• Increasing the ECM density (mostly collagen) of breast tissues increases a patient’s risk of cancer 4-6 times. Shown in mice, increasing the density increases stiffness, and also increases cell proliferation and metastasis.
• Obesity increases breast cancer incidence and prognosis via paracrine cell-cell signaling. Obesity is associated with increases collagen and fibronectin ECM deposition.
• One professor is using a microfluidic device with a VEGF gradient to study blood vessel morphogenesis and sprouting. Increasing the VEGF concentration increases sprouting. Interestingly, with flow there is a decrease in sprouting due to nitric oxide production. Flow also modulates endothelial cell morphogenesis.
• A change in cell spreading (by changing matrix stiffness) alters cytoskeletal tension, which affects the number and strength of focal adhesions. Increasing stiffness increases the force cells exert on micropillars. Different signaling pathways become activated based on cell morphology and the extent of spreading. Surprisingly, in 2D or 3D, increasing stiffness causes an increase or decrease, respectively, in cell spreading.