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Dec 06, 2019

RPG Seminar Series (Speaker: Dr. TSANG Yiu Cheung / Mr. WONG Tsz Lam)

Date: Friday, 6 December 2019

Venue: Seminar Room 5, LG/F
Laboratory Block, Faculty of Medicine Building
21 Sassoon Road, Hong Kong

Time: 5:00 p.m.

Title: Status of EBV infection in gingival epithelium
Speaker: Dr. TSANG Yiu Cheung (PhD candidate)

EBV has been detected in saliva consistently, but its origin has not been clearly elucidated. Back in the 1980s, Sixbey and coworkers from the EBV research community reported the finding of EBV DNA in oropharyngeal epithelium from infectious mononucleosis patients but this finding has not been reproduced by other researchers in later years. While, on the other hand, from the dental research community, EBV was consistently reported to be found from periodontal pockets within the gingiva when associated with periodontal disease. The discrepancies between the two different disciplines of studies trigger an interesting question: Does the EBV originate from the oral cavity or pharyngeal cavity? If so, does EBV-infected gingival epithelium contribute to EBV in saliva? Is there any convincing evidence showing the infection of EBV within the gingival epithelial cells? If the gingival epithelial cells are infected with EBV, would it be latent or lytic in nature? Any relationship with gingival diseases? Through care e analysis of gingival biopsies and EBV infection of 2D monolayer and 3D-organotypic cell culture model, we aim to address these questions which will shed lights to the origin of EBV in saliva and contribution of EBV to gingival diseases.

Title: Clinical significance and functional role of protein tyrosine kinase 7 (PTK7) in hepatocellular carcinoma metastasis
Speaker: Mr. WONG Tsz Lam Matthew (PhD candidate)

The recurrence and metastasis of hepatocellular carcinoma (HCC) portends a poor prognosis and represents important clinical challenges. As a result, identifying key regulators in metastasis and developing targeted therapies are critical to prolonging HCC patient survival. Protein kinases have drawn growing attention as treatment targets due to their crucial role in modulating oncogenic pathways, with over 30 kinase inhibitors now approved for cancer treatment. Our team has lately identified protein tyrosine kinase 7 (PTK7) as one of the top deregulated kinases in both recurrent and metastatic HCC using publicly available datasets. The overexpression of PTK7 in advanced stage tumours and its correlation with worst survival was further validated through immunohistochemistry using tissue microarrays. Functionally, the ability of HCC cells to metastasize is inhibited through the knockout of PTK7 by CRISPR/Cas9 system but stimulated when PTK7 is overexpressed or supplanted extracellularly as recombinant protein. Similarly, flow cytometry sorted PTK7+ HCC cells display enhanced abilities to migrate and invade than PTK7- counterparts. In animal models, PTK7-overexpressing cells orthotopically injected to the liver resulted in more frequent lung metastases. Lastly, a PTK7-specific antibody-drug conjugate was found to moderately but selectively target PTK7-expressing HCC cells, representing a novel therapeutic option. The upstream activator of PTK7 as well as the downstream mechanism by which PTK7 mediates HCC metastasis are currently investigated.