EBV Conference 2008 Guangzhou - Baylor College of Medicine

37 (RegID: 1062)
Maria Lung
Institution: Hong Kong University of Science & Technology
e-mail: bomaria@ust.hk
FUNCTIONAL CHARACTERIZATION OF A CHROMOSOME 11 CANDIDATE TUMOR
SUPPRESSOR GENE, THY1, IN NASOPHARYNGEAL CARCINOMA
HL Lung, AKL Cheung, Y Cheng, FM Kwong, PHY Lo, EWL Law, D Chua, ER Zabarovsky, N Wang,
SW Tsao, EJ Stanbridge, ML Lung
Oralabstract:
Previous studies on identifying chromosome 11 critical regions associated with functional suppression of
tumor formation in nasopharyngeal carcinoma (NPC) utilized a monochromosome transfer and
complementation approach, which successfully identified several candidate tumor suppressor genes (TSGs)
mapping to chromosome 11q22-q23. These include CADM1 (Cell Adhesion Molecule 1, formerly known
as TSLC1), THY1 (THY1 cell surface antigen), and CRYAB (crystalline alpha B). Our previous studies
suggested that THY1 is a good candidate TSG associated with lymph node metastases in NPC. To
examine the tumor-suppressive activity of THY1, we have now used the in vivo tumorigenicity assay,
performed using a tetracycline-regulated expression vector system. Tumorigenicity results show that the
activation of THY1 suppresses tumor formation of HONE1 cells in nude mice. Tumor formation ability
was restored in the presence of doxycycline, when the gene is selectively shut off. Additional functional
studies were performed and results indicate expression of THY1 inhibits HONE1 cell growth in vitro,
induces cell cycle arrest, reduces anchorage-independent growth, and inhibits cell invasiveness. An
interesting novel link between THY1 and our other two chromosome 11q23 candidate tumor suppressors,
CADM1 and CRYAB, indicate there may be potential collaborative interactions of these closely mapping
genes. Gene expression levels of CADM1 and CRYAB appear to be tightly regulated by THY1 in HONE1
cells. This possibility is currently being tested.
EBV Conference 2008 Guangzhou
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