Cancer Cell Invasion Is Enhanced by Applied Mechanical Stimulation

Metastatic cells migrate from the site of the primary tumor, through the stroma, into the blood and lymphatic vessels, finally colonizing various other tissues to form secondary tumors. Numerous studies have been done to identify the stimuli that drive the metastatic cascade. This has led to the identification of multiple biochemical signals that promote metastasis. However, information on the role of mechanical factors in cancer metastasis has been limited to the affect of compliance. Interestingly, the tumor microenvironment is rich in many cell types including highly contractile cells that are responsible for extensive remodeling and production of the dense extracellular matrix surrounding the cancerous tissue. We hypothesize that the mechanical forces produced by remodeling activities of cells in the tumor microenvironment contribute to the invasion efficiency of metastatic cells. We have discovered a significant difference in the extent of invasion in mechanically stimulated verses non-stimulated cell culture environments. Furthermore, this mechanically enhanced invasion is dependent upon substrate protein composition, and influenced by topography. Finally, we have found that the protein cofilin is needed to sense the mechanical stimuli that enhances invasion. We conclude that other types of mechanical signals in the tumor microenvironment, besides the rigidity, can enhance the invasive abilities of cancer cells in vitro. We further propose that in vivo, non-cancerous cells located within the tumor micro-environment may be capable of providing the necessary mechanical stimulus during the remodeling of the extracellular matrix surrounding the tumor

Vessel architectural imaging identifies cancer patient responders to anti-angiogenic therapy

Measurement of vessel caliber by Magnetic Resonance Imaging (MRI) is a valuable technique for in vivo monitoring of hemodynamic status and vascular development, especially in the brain. Here, we introduce a new paradigm in MRI coined as Vessel Architectural Imaging (VAI) that exploits an intriguing and overlooked temporal shift in the MR signal forming the basis for vessel caliber estimation and show how this phenomenon can reveal new information on vessel type and function not assessed by any other non-invasive imaging technique. We also show how this biomarker can provide novel biological insights into the treatment of cancer patients. As an example, we demonstrate using VAI that anti-angiogenic therapy can improve microcirculation and oxygen saturation levels and reduce vessel calibers in patients with recurrent glioblastomas, and more crucially, that patients with these responses have prolonged survival. Thus, VAI has the potential to identify patients who would benefit from therapies