In Vitro Model of Inflammatory Signaling and Cancer Stem Cell Signaling in Pancreatic Cancer using 3D Hetero-Cellular Spheroids and MicroRNA Delivery using Hyaluronic Acid-Based Nanoparticles

Pancreatic cancer is one of the most aggressive cancers worldwide with an extremely poor prognosis. There is a largely unmet clinical need for the development of effective therapies for its treatment. Most incidences of pancreatic cancer in patients are a direct result of chronic pancreatitis. This chronic inflammatory state is strongly implicated in bringing about a mutation of healthy cells into tumor cells. Also, the cross-talk between tumor cells and their in-vivo stromal microenvironment, containing macrophages, fibroblasts and other tumor-associated cells through various cytokines results in the development of a more aggressive and malignant phenotype.;Additionally, the three dimensional environment of a tumor contains an outer proliferative zone, with a healthy supply of blood vessels and thereby, oxygen and other necessary nutrients that are required for cell growth. However, the inner core of a tumor is necrotic and hypoxic due to diminished blood supply. This oxygen gradient contributes towards the development of a stem cell like phenotype among the tumor cells, which is more metastatic and aggressive.;These inflammatory and cancer stem cell signaling pathways are regulated by a number of small non-coding micro-RNAs (miRNAs) that are present endogenously. Exogenous delivery of miRNA or miRNA mimics to induce silencing of pro-oncogenic genes and to increase expression of tumor-suppressive genes is emerging as an efficacious platform to modulate the phenotype of tumor cells as these are highly selective to their targets compared to small molecule therapies.;However, most anti-cancer therapies use cell monolayers as a model to test efficacy. These models do not recapitulate the complex signaling pathways that occur in vivo in tumors. Therefore, therapies that show promise in these monolayer platforms do not necessarily have translatable efficacies in vivo. Thus, the establishment of a hetero-cellular, three-dimensional in-vitro tumor model is essential to mimic in vivo hypoxic microenvironments and the dynamic interplay between tumor cells, macrophages and fibroblasts.;This MS dissertation project will focuses on the establishment of such an in vitro spheroid model, an analysis of the inflammatory and cancer stem cell-like phenotype and the evaluation of a nano-scale, hyaluronic acid (HA) based miRNA delivery system to modulate the phenotype of the tumor cells. The delivery system will be evaluated for uptake, transfection within spheroid models. Finally downstream effects of the tumor suppressive microRNA will be evaluated through cytotoxicity studies.