Glycosylphosphatidylinositol transamidase complex (GPIT) is a multisubunit membrane-bound enzyme which is essential for anchoring of GPI-anchoring proteins on the cell membrane. It is composed of five subunits, i.e. PIGU, PIGT, PIGK, GPAA1, and PIGS. We previously demonstrated that PIGU is an oncogene in human bladder cancer. We further found that PIGT and GPAA1 were overexpressed in human breast cancer and contributed to invasion in human breast cancer. Furthermore, we recently found that, in contrast to overexpression of PIGU, PIGT and GPAA1 in various human cancers, the subunit PIGK displayed a significant downregulation in bladder, liver and colon cancer tissues and various bladder cancer cell lines, i.e., 5637, UMUC-3 and SW780. To evaluate the downregulation of PIGK in bladder cancer, we performed epigenetic and genetic mutation analysis. We did not find any hypermethylation on the promoter of PIGK. However, we identified a point mutation in 3\#8217;-UTR of PIGK in various bladder cancer cell lines and tissue samples, which is highly associated with the downregulation of PIGK in bladder cancer. Collectively, our study demonstrates PIGK suppression in bladder cancer and further effort is ongoing to decipher the underlying mechanisms.

Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 621.

100th AACR Annual Meeting-- Apr 18-22, 2009; Denver, CO