Impact of Stretching on Tumor growth and Metastasis

National Institute Of Dental & Craniofacial Research

Investigators

Abstract

Cancer is among the most serious health problems worldwide, and this situation urges multiple efforts to develop new more effective and less toxic treatments. There has been interest in developing non-pharmacological treatments that could boost natural defenses against cancer and contribute to primary and secondary cancer prevention. Among these, exercise has received a significant amount of attention due to the well-documented positive association between physical activity and survival in many cancer types. However, to date, physical modalities are not used specifically to modify the process of tumor formation. Animal studies of exercise in cancer models have yielded mixed results. Furthermore, these studies have involved levels of vigorous aerobic exercise that can be difficult to achieve in cancer patients. On the other hand, gentle movement-based techniques such as yoga, tai chi and qi gong are popular and well tolerated among cancer patients for managing symptoms and improving mobility and well-being. Stretching of tissues is a component of these techniques that has not been extensively studied but could have important effects on the cancer itself. Our recent studies show that gentle daily stretching for 10 minutes can have profound effects on reducing local connective tissue inflammation and fibrosis in several rodent models, via direct mechanical effects on the stretched tissues. We have also demonstrated a 52% reduction of mammary tumor growth over one month in mice undergoing stretching for 10 minutes once a day, without any other form of therapy. In this project, we will use this animal model aiming to: A) Explore the impact of stretching on tumor growth and the progression to metastasis. B) Investigate the mechanisms of the effect of stretching on tumor growth. The effect of Stretching is being tested tested in the polyoma middle T (MMTV-PyVmT) mouse breast cancer model, which is highly metastatic. We have preliminary data suggesting a significant effect of stretching on tumor growth. We are using dual photon second harmonic (SHG) imaging to visualize tumor collagen structure and extracellular matrix: Cell lines carrying polyoma middle T transgene (Met-1) were GFP tagged using a Lentiviral plasmid system to track the implanted tumors. Images of the entire tumor and its surroundings have been taken. We are currently analyzing these images using a software called CurveAling to quantify fibrillar collagen alignment to determinate if stretching impact collagen architecture with possible repercussions in tumor growth and metastasis We have quantified lung metastasis following the mechanic intervention PYMT Transgenic model: A colony of PYMT mice has been created and we are in the process of analyzing the effect of stretching on tumor growth and metastasis We are also planning to do a single cell RNAseq experiment to explore into the mechanism of stretching. GOALS: Complete analysis of orthotopic model SHG Complete analysis metastasis orthotopic model Start scRNAseq with Orthotopic model Complete establishing Transgenic Model In vitro model: Using 2D and 3D cultures from a breast cancer cell line (Met-1), we have established an in vitro model to study the effect of stretching at cellular level. We have developed 3D cultures with Met-1 (PYMT cell line), which organize into organoids that are embedded into collagen gels. Collagen embedded-organoids are either stretched or not stretched and analyzed for biological markers such as Ki-67, caspase-3, progesterone receptor, estrogen receptor, cadherin. GOALS: Establish conditions for mechanical intervention on 3D model (spheroids) Measure biologics markers in spheroids