Defects in autophagy were implicated in the development of cancer nearly 30 years ago, and recent study reported that tumor cells display the lower level of autophagic activity than normal cells. In this study, we found that the mRNA level of TM40 is decreased in ovarian cancer by microarray analysis. RT-PCR analysis confirmed that TM40 level is reduced in most of ovarian cancer tissues. To examine the subcellular localization of TM40, confocal microscopy were performed in HEK293 and COS-7 cells and TM40 showed the vesicle form in the cytoplasm. Further analysis revealed that TM40 was co-localized with GFP-LC3, authophagosome marker, indicating that TM40 is involved in autophagy. The ectopic expression of TM40 induced the autophagosome formation in COS-7 cells, while C-terminal truncated mutant did not. These results lead us to the conclusion that the reduced expression of TM40 results in the autophagy inhibition in ovarian cancer.

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA