Pancreatic cancer is a devastating disease with a 5-year survival rate of less than 6%. This poor outcome is heavily associated with the resistance of pancreatic tumors to chemotherapy and radiation therapy. The profound heterogeneity of pancreatic tumors is speculated to be one key reason for this intense resistance. To improve treatment outcome, it is crucial to evaluate the characteristics of pancreatic adenocarcinoma for each patient and to select or adapt tumor-specific therapy accordingly. Over the past ten years, evidence has pointed to the importance of circulating tumor cells (CTCs) in the spread of cancer through the metastatic process. These cells are shed by the primary tumor into the circulation and are now known to be key players in metastasis.CTCs are believed to be a good surrogate biomarker for not only prognosis, but also for cancer detection and development of personalized treatment. This thesis outlines the use of a microfluidic device that allows for the isolation, expansion, and characterization of pancreatic CTCs. This device, named the Labyrinth, allows for the label free isolation of CTCs at a high throughput of 2.5mL/min, offering a biomarker independent CTC characterization platform to study heterogeneity among CTC subpopulations in pancreatic cancer. This Labyrinth allows for a high CTC recovery of 92%, while having a WBC removal of 89%. The Labyrinth technology was used to investigate the use of CTCs for clinical prognosis. This was performed through a clinical study, where CTCs were isolated and enumerated for over 150 treatment naïve patient samples. CTC counts were then correlated with treatment efficacy (surgery, chemotherapy or radiotherapy). Our results show for all treatment options there is a statistically significant decrease in CTC counts. Lastly, a trend was observed between the decrease of CTC count and higher overall survival among all treatment options. The employment of the Labyrinth for heterogeneity studies was then explored in this thesis. CTCs isolated from pancreatic cancer patients were monitored for markers associated with the cancer EMT cell population including CK, CD24, and CD90. We found that there were cells that were CK+, which were then characterized as CTCs, that also had CSC markers associated with them in most cases. Tissue analysis (IHC) from one of the patients showed the existence of this CTC subpopulation close to the tumor vasculature, suggesting their aggressiveness and ability to travel to the bloodstream to invade other organs.This thesis also describes in vitro and in vivo characterization performed on expanded CTCs. CTCs were isolated from ten pancreatic cancer patients with locally advanced disease using the Labyrinth and expanded in vitro for over 30 days. Expansion of CTCs was successfully achieved for 3 of the samples, giving a 30% success rate. CTC cultures were then characterized in both 2D (adherent) and 3D (spheroid) in vitro conditions. Furthermore, an in vivo study model (NOD SCID mice) was created, being the first ever pancreatic CDX model. This model displayed metastasis across several organs after only 3 weeks of CTC injection.CTCs could serve as a potential avenue for a non-invasive alternative to diagnosing and treating pancreatic cancer and thereupon preventing the development of the disease. The isolation and expansion of CTCs, the heterogeneous population of cells that promote metastasis, can provide meaningful information to elucidate the process of pancreatic tumorigenesis to preempt its fatal result.
【 预 览 】
附件列表
Files
Size
Format
View
Application of Label-free Microfluidic Technologies for the Enrichment, Expansion and Characterization of Circulating Tumor Cells in Pancreatic Cancer
PDF
download
878987797
028-85220240
