Project title p21-activated kinase 4: a prognostic and therapeutic target for ovarian carcinoma?
Principal investigator Dr Michelle K. Y. Siu, Research Assistant Professor, Department of Pathology, The University of Hong Kong
Co-investigator(s) Prof Annie N.Y. Cheung, Departments of Pathology, The University of Hong Kong
    Prof Hextan Y.S. Ngan, Obstetrics and Gynaecology, The University of Hong Kong

Project Objectives

Ovarian cancer is a lethal gynecological malignancy. To improve patients’ survival, it is important to identify novel prognostic and therapeutic targets. In this study, the role of p21-activated kinase 4 (Pak4) in ovarian cancer progression was investigated. We demonstrate a significant association between increased expression of Pak4 and its activated form, phosphorylated (p)-Pak4 Ser474, with metastasis of ovarian cancers, shorter overall and disease-free survival, advanced stage and high grade cancers, serous/clear cell histological subtypes and reduced chemosensitivity. Pak4 overexpression was also observed in ovarian cancer cell lines. Pak4 and p-Pak4 expression were detected both in the nucleus and cytoplasm of ovarian cancer cells, in vitro as well as in vivo. Stable knockdown of Pak4 in ovarian cancer cell lines led to reduced cell migration and invasion along with reduced c-Src and ERK1/2 activation and decreased matrix metalloproteinase 2 expression, demonstrating a physiological link between Pak4, c-Src, ERK1/2 and MMP2. Conversely, ectopic Pak4 overexpression enhanced cell migration and invasion in a kinase-dependent manner. This is the first report revealing the association between Pak4 and important clinicopathologic parameters, suggesting Pak4 to be a significant prognostic marker and potential therapeutic molecular target in ovarian cancer.

Nasopharyngeal Carcinoma (NPC)
The research on Nasopharyngeal Carcinoma (NPC) is led by Dr. Law Chun-key of the Department of Clinical Oncology of Queen Elizabeth Hospital and financially assisted by our Society.
(A) Inflammation related gene discovery in NPC patients treated with an anti-inflammatory drug – Celecoxib
We continue to perform gene chip analysis in the nasopharyngeal tissues obtained from a cohort of nasopharyngeal cancer (NPC) patients before and after treatment by an anti-inflammation drug, Celebrex followed by radiotherapy with or without chemotherapy in collaboration with University of Hong Kong. More cases were studied and RNA was extracted from the cancer and normal tissues. It was then amplified to generate sufficient quantity of cDNA for gene chip experiment. The cDNA was labeled with two fluorescent dyes, Cy5 and Cy3 for genetic hybridization experiments onto gene chip. More than half of the cases were performed. Interim analysis of the results will be carried out in this larger number of cohort to select reliable gene markers correlating with this malignancy and treatment so that further applications in diagnosis, prognostication and treatment can be explored. Subsequent RT-PCR experiments will be performed to confirm the tumor and treatment specificity of these gene markers. Functional analyses will also be carried out to examine the roles these gene markers play in the carcinogenesis process of NPC.
(B) Identification of protein markers by protein chip array profiling
Two areas of proteomics work were being studied with one area in NPC and the other in lymphoma. Proteomic analyses of chemotherapy related peptide markers in NPC are being carried out in this project. A number of peptide markers which are associated with chemo-response have been found. A manuscript is under preparation to report this finding. More and more studies indicate that cancer is a kind of chronic inflammation and cancer patients share many inflammatory proteins or peptides with patients who suffer from bacterial or viral infection and presented with inflammation symptoms. We have performed serum proteomics analysis in lymphoma and SARS patients. In this study, we compare the proteomic data generated from the lymphoma patients and another set of data generated from the SARS patients with severe inflammation. We aim to find specific set of markers associated with lymphoma and inflammation diseases. Markers common to both were also examined to try to delineate the carcinogenesis process involving chronic inflammation. A manuscript is under preparation to report this finding.
(C) CpG island microarray analysis of cancer
DNA methylation of tumor suppressor genes is a frequent event occurring in cancer patients. Using high density CpG island microarray technology, we examine the methylation status in 244,000 gene promoters. A large battery of methylated genes were found. By means of methylated specific PCR and bisulphite sequencing technologies, we are now confirming the results. The transcript expression of these genes are also examined by RT-PCR. We will report the findings of this study when the quantities of the methylated genes found reach a substantial level and their methylation status is confirmed.