Poster Sessions

CANCER-5

Panomwat Amornphimoltham

P. Amornphimoltham, K. Leelahavanishkul, A. Molinolo, J.S. Gutkind, R. Weigert

Emerging Role of the RAB25 GTPase in Head and Neck Cancer Metastasis

Despite of advances in treatment modalities, 5-year survival rate of head and neck cancer patients is approximately 50% due to the recurrences and secondary neoplasm. Indeed, understanding the metastatic and invasive cell motility in the tumor microenvironment is critical for treatment and prevention. Recently, we have established human head and neck primary cell lines composed of cells acquired the tumorigenicity and metastasis in mouse tongue tumor xenograft. Gene array analysis of these cells demonstrates the differential expression of a number of molecules involved in membrane trafficking process among metastasis and non-metastasis cells. Among them, the loss of RAB25, small GTPases essential for membrane protein recycling and translocation from trans-Golgi network to plasma membrane in metastatic cell lines. Indeed, expression of RAB25 in the metastatic cells displayed significant arrest of cell invasion and metastatic both in vitro and in vivo model. Further more, intravital imaging technique in tongue xenograft with the genetically modified both to express a fluorescent marker and to either express (or ablate) RAB25 in metastatic and non-metastatic cells, respectively, allow us to investigate the interaction of the tumor and the tumor microenvironment that contribute to the metastatic invasion of this cancer in the physiologic condition.