Relevant Thesis-Based Degree Programs
Graduate Student Supervision
Doctoral Student Supervision
Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.
Clear-cell renal cell carcinoma (ccRCC) is a disease with aberrant angiogenic and immunosuppressive features. Metastatic ccRCC patients are treated with targeted therapies based on clinical features: favorable-risk patients with a combination of anti-angiogenic and immunogenic drugs, and intermediate/high-risk patients with immunotherapies. In this doctoral research project, I hypothesized that targeted treatment against factor(s) augmented through drug-resistance development could revert to responding to therapy. I further theorized that ccRCC patients could be sub-classified into treatment groups that might guide therapy decision-making in a personalized manner.Patients treated with anti-angiogenic drugs, e.g. sunitinib, eventually develop resistance and the underlying molecular mechanism is unknown. In Objective 1, I found that an evolutionarily conserved protein, Y-box binding protein 1 (YB-1), and its downstream target, ATP-binding cassette sub-family B member 1 (ABCB-1), were upregulated in acquired sunitinib-resistant in vitro, ex vivo, in vivo and patient samples when compared to sensitive samples. Moreover, co-administration of ABCB-1 inhibitor, elacridar, reverted the sunitinib-resistance in mccRCC tumors.Further anomalies in the expression pattern of ccRCC tumors were explored in Objective 2 and a novel gene signature to sub-classify ccRCC patients was identified. I analyzed the expression profile of 469 ccRCC patients and developed a refined 66-gene signature for improved sub-classification of patients (Angiogenic, Unknown, T-effector). In my 66-gene signature, I identified a novel comprehensive expression profile to distinguish migratory stromal from immune cells. Moreover, “Angiogenic” tumors with higher expression of endothelin-1 (EDN1), endothelin receptor A (EDNRA) and endothelin receptor B (EDNRB) had decreased levels of immune cell gene expression. Previous research showed that EDNRB modulates T-cell infiltration into solid tumors. Augmenting prior research, under Objective 2, the “cross-talk” between tumor vasculature and immune microenvironment (TIME) was explored. Altogether, my thesis identified one possible mechanism of acquired sunitinib-resistance development and potential therapy in mccRCC tumors. The thesis also established that ccRCC tumors have different expression patterns that could be sub-classified into distinct groups. The proposed sub-classification might guide treatment decision-making and, potentially, enable the use of personalized medicine in ccRCC patients increasing treatment response and survival.
The sonic hedgehog (SHH) signaling pathway has been shown to play an integral role in the maintenance and progression of bladder cancer (BCa). Smoothened inhibitors are currently used in the clinic for treatment of some skin cancers, however they have not been evaluated in BCa and SHH inhibition may be an efficacious strategy for BCa treatment. I assessed an in-house human BCa tissue microarray comprising non-invasive, invasive and lymph node metastasized transitional cell carcinoma and found that the transcription factors downstream of SHH, Gli1 and Gli2, were increased in more aggressive tumors. A panel of BCa cell lines show that two invasive lines, UM-UC-3 and 253J-BV, both express these transcription factors but differ in other parameters in the SHH pathway. UM-UC-3 produces greater quantities of SHH ligand, is less responsive in viability to pathway stimulation by recombinant human SHH or SAG, and less responsive to inhibition by a variety of molecules including the Smoothened inhibitors cyclopamine and SANT-1. 253J-BV, on the other hand, was highly responsive to these manipulations and appears more representative of canonical SHH signaling while UM-UC-3 resembles non-canonical autocrine signaling. To overcome this variability I utilized a Gli1 and Gli2 antisense oligonucleotide (ASO) to bypass pathway mechanics and target the transcription factors directly. UM-UC-3 decreased in viability due to both ASOs but 253J-BV was only affected by Gli2 ASO. IC50s were in the nanomolar range. To evaluate in vivo efficacy I developed a murine intravesical orthotopic human bladder cancer (mio-hBC) model for the establishment of non-invasive urothelial cell carcinomas. In this model I pre-treat the bladder with poly-L-lysine for 15 minutes, followed by intravesical instillation of luciferase–transfected human UM-UC-3 cells. Cancer cells are quantified by bioluminescent imaging. Tumors grew to 541.6±0.75 fold (Mean±SE) initial size after 40 days and were confirmed to reflect patient samples by a response to mitomycin C. Treatment of these tumors with Gli2 ASO resulted in decreased tumor size, growth rate and Gli2 mRNA and protein expression. These results validate this model and support the conclusion that Gli2 ASO may be a promising new targeted therapy for BCa.
Master's Student Supervision
Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.
End-stage renal disease (ESRD) is a condition where the kidneys fail to effectively filter waste and excess fluids from the blood. In Canada, the number of ESRD patients has increased by 24% over the past decade. While dialysis is a treatment option, kidney transplantation remains the gold standard due to higher survival rates. Unfortunately, there is a shortage of available organs for transplantation. Tissue engineering has emerged as a potential solution to address this shortage. The extracellular matrix (ECM) obtained from decellularized organs retains the organ's intricate microarchitecture and bioactive molecules crucial for successful recellularization. In order to regenerate a kidney, it must be reseeded with new cells after the decellularization process. However, achieving complete organ repopulation remains a challenge. Therefore, the current study aims to evaluate different methods for kidney recellularization that can potentially be functional for transplantation. Pig kidneys were decellularized using a meticulous protocol involving detergent perfusion through the renal artery and vein. The resulting ECM was analyzed histologically and characterized using proteomic analysis, ensuring the preservation of growth factors and structural proteins. Primary porcine renal cells, labeled as whole kidney pig cells (WKPC), were isolated, cultured, and extensively characterized using RT-qPCR, immunofluorescence, and flow cytometry. Recellularization of a whole pig kidney was performed using an in vitro bioreactor and negative pressure over a 12-day period, with WKPC perfusion and co-perfusion of human erythrocytes to enhance oxygenation. Successful decellularization of a pig kidney was achieved within 45 hours, preserving the ECM's integrity and important biomolecules. The isolated WKPC population exhibited the presence of native cell markers, confirming their suitability for kidney recellularization. Histological evaluation revealed a high density of cells distributed throughout the ECM matrix, extending to the organ's periphery. Analysis of the culture media and immunohistochemistry showed cells proliferating and no signs of cell death. Moreover, the presence of cell colonies expressing kidney cell markers in different kidney sections confirmed improvement in the recellularization process. This research serves as a proof-of-concept, laying the foundation for the potential translation of this technology to recellularize human kidneys, ultimately addressing the organ shortage and improving outcomes for ESRD patients.
Background: As COVID-19 spread, efforts were made to preserve hospital resources to prepare for the anticipated surge of COVID-19 patients. However, the relationship between COVID-19 hospitalizations and access to cancer surgery is unknown. In this project, we analyze the impact of COVID-19 patient volume and wait time for cancer surgery. We also investigate the effect on wait time for non-cancer surgery, the number of surgeries performed, and the number of patients waiting for surgery. Methods: We conducted a population-based retrospective study using electronic databases and registries and examined regional surgical wait times and COVID-19 patient volumes to produce a qualitative analysis. The regional volume of surgery and patients waiting for surgery were also analysed for cancer and non-cancer diagnosis groups. Results: Changes in regional, weekly median wait time for priority and other cancer surgery were independent of COVID-19 patient volume. In the first phase of the pandemic, volume of patients and wait time for urgent surgery is shortened while volume of patients and wait time for non-urgent surgery is extended. In the second phase, for all diagnosis groups, wait time recovers. In the third phase, volume of patients waiting for all surgeries increases. Conclusion: Regional COVID-19 patient hospitalization in critical and non-critical care did not affect cancer surgery access. If further supported by future studies, cancellation of non-urgent surgeries as mandated by provincial governments, and institutional actions in upholding the efficiency of the health system are likely to act as influential factors in access to cancer surgery.
Cancer is currently the leading cause of death in Canada and is responsible for 30% of all deaths. With various treatments available nowadays, it is necessary to develop a three-dimensional (3D) model to mimic in vivo condition of patients’ disease in order to test drug efficacy prior to any actual treatments. My study is focusing specifically on kidney and bladder cancer. Therefore, a 3D, acellular organ-specific extracellular matrix (ECM) can be established as bioactive substrates with the long-range goal of bioengineering tumors for drug testing. Specifically, decellularization is the process by which cells are removed from the organ to produce the aforementioned matrix. It is crucial to achieve a tight balance between effective cell removal and retention of native ECM architecture. Henceforth, the decellularized matrix can be used as a template and be repopulated with normal human organ-specific cells or cancerous cells. With these approaches, a bio-matrix that ultimately serves as a cancer model for drug testing can be developed. In this master’s thesis project, I hypothesized that decellularization preserves organ microarchitecture and retains various matrix-bound growth factors necessary for cell homing. Afterward, tumor models can be established through recellularization of human cells onto the decellularized ECMs as a proof-of-principle drug-testing platform to predict treatment response.Two objectives were pursued to test this hypothesis. Under objective 1, I optimized and established decellularization protocols for both kidney and bladder. The protocols ensure complete cell removal and preservation of ECM microarchitectures. In addition, comprehensive protein-profiling of the decellularized kidney and bladder’s ECM was completed by performing proteomic analysis with liquid chromatography–mass spectrometry (LC-MS/MS). Under objective 2, recellularization protocols for both decellularized kidney and bladder ECM were established and optimized. As the decellularized kidney and bladder’s ECM was repopulated with normal human cells and cancerous cells, the proposed in vitro urogenital cancer model can be developed.In conclusion, a 3D in vitro urogenital cancer model can be developed from kidneys and bladders using protocols optimized under objective 1 & 2. This work establishes the model as proof –of principal and sets the foundation for the developments of personalized cancer treatments.