The Molecular Mechanism Of AP-2γ Gene In Testicular Germ Cell Tumors Occur

Testicular germ cell tumors (TGCTs), which occur in the 20-40 year-old young men with. The morbility and mortality have been increasing gradually in the world.but the cause of TGCTs is still unknown. Currently, the main treatment for TGCTs are surgery, radiotherapy and chemotherapy, but the survival is low as before. In order to improve the survival, it is vital to investigate the molecular and pathological mechanisms of the occurrence of TGCTs.Recent studies found AP-2y gene is a novel marker for TGCTs. The AP-2y gene plays an important role in cell proliferation, differentiation, embryonic development and carcinogenesis. In our paper, we investigated the effect of AP-2y gene in the occurrence of TGCTs.First, we confirmed high expression of AP-2y in abnormal cancerous tissues of TGCTs patients and no expression in normal intratubule by immunohistochemistry. The bioinformatics analysis of AP-2y had shown that the AP-2y promoter contains Oct-4 and SRY binding sites. The results of Oct-4 and SRY binding to AP-2y promoter were demonstrated by CHIP experiments. AP-2y luciferase wild-type plasmid and mutant plasmid were builded and the luciferase results showed Oct-4 and SRY could down-regulate the expression of AP-2y. When silencing Oct-4 and SRY by siRNA, the luciferase activity and protein level of AP-2y were up-regulated. The co-localization of SRY and Oct-4 in the nucleus of NT2 cells was shown by immunofluorescence experiments.To further study the relationship between SRY, Oct-4 and AP-2y, we constructed mouse cryptorchid animal model. The cryptorchid mouse testis RNA and normal mouse testis RNA were extracted. Real time PCR after reverse transcription revealed SRY, Oct-4 highly expressed in normal mouse and low expressed in cryptorchid mouse. At the same time, we found low-expression of AP-2y in nomal mouse, but high-expression in cryptorchid mouse.These results suggest that Oct-4 and SRY can bind to AP-2y promoter and down-regulate the expressed activity of AP-2y. So it demonstrates the important role of AP-2y in the occurrence of germ cell tumors.