Renal cell carcinoma (RCC), following prostate and bladder tumours, is the third most prevalent genitourinary malignancy. Clear cell renal cell carcinoma makes up the bulk of RCC cases (ccRCC). Despite the fact that ccRCC is the most aggressive type of RCC, our understanding of its pathophysiology is limited. Previous research in our laboratory revealed important oncogenic roles of contactin 1 (CNTN1), a neuronal cell adhesion protein, in prostate cancer. CNTN1 is involved in a number of signalling pathways that are often changed in cancer, including the VEGFC-VEGF receptor 3 (VEFGR3)/fms-related tyrosine kinase 4 (Flt4) axis, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) axis, and the Notch signalling system. Collectively, evidence suggests that CNTN1 facilitates ccRCC. To examine this possibility, I have established stable ccRCC 786-O and A498 cell lines expressing either empty vector (EV) or CNTN1. In comparison to the respective EV lines, ectopic expression of CNTN1 enhances colony formation and cell proliferation. In comparison to A498 EV cells, A498 CNTN1 cells seems to possess enhanced migration ability based on wound healing assay. Taken together, my research provides in vitro evidence supporting CNTN1 in facilitating ccRCC pathogenesis. Future research will be required to investigate this concept using in vivo systems and primary ccRCC tumor tissues. / Thesis / Master of Science (MSc)

Traumatic axonal injury (TAI) contributes to the mortality and morbidity following diffuse traumatic brain injury (TBI). Previous work has shown that following TBI, alterations in the molecular domains of axons result in TAI. It is currently posited that injury induced ionic flux is responsible for activating deleterious proteolytic cascades, resulting in altered distributions of axonal components. However, the underlying mechanism of this progressive pathology remains elusive. This study further explores the hypothesis that altered molecular domains contributes to the progressive intra-axonal changes that characterize TAI. Using a rodent model of impact acceleration TBI we examined the expression of nodal and paranodal domains of myelinated axons in brainstem over a 24 h period post-injury. Western blot analysis was utilized to quantify changes in protein levels of Nav1.6, a prominent component at the node of Ranvier, and Caspr, a constituent of the paranodal tripartite complex. Here we report that diffuse TBI causes an up-regulation of Nav1.6 and a down-regulation of Caspr over a 24 h time-course post-injury. The results of this study support that alterations in the molecular components of the domains of injured axons contribute to the cellular mechanism of TAI and thus provides novel data in the field of TBI research.

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