DEVELOPMENT OF A MICROFLUIDIC MODEL OF A PANCREATIC ACINUS
thesisposted on 16.08.2019 by Stephanie Michele Venis
In order to distinguish essays and pre-prints from academic theses, we have a separate category. These are often much longer text based documents than a paper.
Pancreatic Ductal Adenocarcinoma (PDAC) continues to have a dismally low survival rate due to late diagnosis and poor treatment options. Therefore, there is a need to understand the early stages and progression of the disease. PDAC is known to have two types of cells of origin: ductal cells or acinar cells. Since acinar-derived PDAC is thought to be the more malignant of the two, it was chosen as the focus of this work. Most studies of acinar cells as they relate to PDAC are accomplished by using animal models such as genetically engineered mouse models. While this method yields a large amount of insight into the progression of the disease and the role of specific genes, it has the drawbacks of being very time and resource intensive. The quicker and less costly alternative is in vitro culture. Specifically, here we have developed a microfluidic model which can incorporate a key aspect of the extracellular matrix (ECM), type I collagen, and mimics the 3D geometry of an in vivo acinus. Most attempts at in vitro culture have been limited by the fact that isolated acinar cells show a decrease in the amount of digestive enzymes they secrete as culture continues. For this reason, we are using a reprogrammed cancer cell line. These cells can be induced with doxycycline to express PTF1a, which allows the cells to adapt acinar characteristics, such as the production of digestive enzymes. We were able to successfully culture and induce PTF1a in these cells within our chip. We showed that the cells exhibit no invasion into the collagen matrix once PTF1a is expressed, thus eliminating a key aspect of cancer cell culture. The cells grown in the chip are confirmed to be producing PRSS2, the digestive enzyme trypsinogen. Collectively, this suggests that we have produced healthy acinar cells growing in the same configuration that they would in vivo. This has many applications in the study of pancreatic ductal adenocarcinoma, as we have developed way to culture reprogramed cancer cells as their benign precursors and maintain acinar characteristics in vitro. It will also have applications in the study of many other pancreatic diseases by providing an in vitro model of a healthy, functional acinus.