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MONOAMINE OXIDASE A IS DOWN-REGULATED IN EBV-ASSOCIATED NASOPHARYNGEAL
CARCINOMA

Hui ML, Sia APE, Li L, Sathasivam HP, Chan MSA, Rajadurai P, Tsang CM, Tsao SW, Murray PG, Tao Q, Paterson IC, Yap LF

Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer that is consistently
associated with Epstein-Barr virus (EBV) infection. In this study, we identify for the first
time a role for monoamine oxidase A (MAOA) in NPC. MAOA is a mitochondrial enzyme
that catalyzes oxidative deamination of neurotransmitters and dietary amines. Depending
on the cancer type, MAOA can either have a tumour-promoting or tumour-suppressive
role. It was shown that MAOA is down-regulated in primary NPC tissues and its down-
regulation enhances the migration of NPC cells. In addition, it was found that EBV infection
can down-regulate MAOA expression in both pre-malignant and malignant nasopharyngeal
epithelial (NPE) cells. It was further demonstrated that MAOA is down-regulated as a result
of IL-6/IL-6R/STAT3 signalling and epigenetic mechanisms, effects that might be attributed
to EBV infection in NPE cells. Taken together, the data highlighted a central role of EBV in
mediating the tumour suppressive effects of MAOA and loss of MAOA could be an
important step in the pathogenesis of NPC.

Published in Scientific Reports volume 10, Article number: 6115 (2020). https://doi.org/10.1038/s41598-020-63150-0. Epub
2020 April 5

Dr Hui Min Lee Dr Chi Man Tsang
Dr Alice Pei Eal Sia Dr Sai Wah Tsao
Dr Melissa Sue Ann Chan School of Biomedical Sciences and Center for Cancer Research
Dr Lee Fah Yap Li Ka Shing Faculty of Medicine
Department of Oral and Craniofacial Sciences The University of Hong Kong
Faculty of Dentistry Shatin Hong Kong
University of Malaya Department of Anatomical and Cellular Pathology and State Key
Kuala Lumpur Malaysia Laboratory of Translational Oncology
The Chinese University of Hong Kong, Pokfulam
Dr Lili Li Hong Kong
Dr Qian Tao
Cancer Epigenetics Laboratory Dr Paul G. Murray
Department of Clinical Oncology Health Research Institute, University of Limerick
State Key Laboratory of Translational Oncology Limerick Ireland
Sir YK Pao Center for Cancer and Institute of Immunology and Immunotherapy
Li Ka Shing Institute of Health Sciences University of Birmingham Birmingham
The Chinese University of Hong Kong, Shatin United Kingdom
Hong Kong
Dr Ian C.Paterson
Dr Hans Prakash Sathasivam Department of Oral and Craniofacial Sciences
Cancer Research Centre Faculty of Dentistry, University of Malaya
Institute for Medical Research Kuala Lumpur Malaysia
Shah Alam Malaysia Oral Cancer Research and Coordinating Center
Faculty of Dentistry
Dr Pathmanathan Rajadurai University of Malaya
Sime Darby Medical Centre Subang Jaya Kuala Lumpur Malaysia
Subang Jaya Malaysia

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