No abstract

Prostate cancer, the most frequent solid cancer in older men, is a leading cause of cancer deaths. Although proliferation and differentiation of normal prostate epithelia andtheinitialgrowthofprostatecancercellsareandrogendependent, prostate cancers ultimately become androgen-independent and refractory to hormone therapy. The prostate-specific antigen (PSA) gene has been widely used as a diagnostic indicator for androgen-dependent and -independent prostate cancer. Androgen-induced and prostate epithelium-specific PSA expression is regulated by a proximal promoter and an upstream enhancer via several androgen receptor binding sites. However, little progress has been made in identifying androgen-independent regulatory elements involved in PSA gene regulation. We report the isolation of a novel, prostate epithelium-specific Ets transcription factor, PDEF (prostate-derived Ets factor), that among the Ets family uniquely prefers binding to a GGAT rather than a GGAA core. PDEF acts as an androgen-independent transcriptional activator of the PSA promoter. PDEF also directly interacts with the DNA binding domain of androgen receptor and enhances androgen-mediated activation of the PSA promoter. Our results, as well as the critical roles of other Ets factors in cellular differentiation and tumorigenesis, strongly suggest that PDEF is an important regulator of prostate gland and/or prostate cancer development.

Xenotransplantation of porcine tissues has the potential to treat a wide variety of major health problems including organ failure and diabetes. Balanced against the potential benefits of xenotransplantation, however, is the risk of human infection with a porcine microorganism. In particular, the transmission of porcine endogenous retrovirus (

The replication of porcine endogenous retrovirus subgroup A (PERV-A

Embryonic stem (ES) cells provide a unique source for tissue regeneration. We examined whether mouse ES cells can efficiently differentiate into transplantable hepatocytes. ES cells were implanted into mouse livers 24 hours after carbon tetrachloride intoxication; ES-derived cells with several hepatocyte-cell-markers were generated. They were able to grow in vitro and showed morphology consistent with typical mature hepatocytes and expressed hepatocyte-specific genes. After transplantation into the carbon tetrachloride-injured mouse liver, ES-derived green fluorescent protein-positive cells were incorporated into liver tissue and rescued mice from hepatic injury. No teratoma formation was observed in the transplant recipients. In conclusion, ES cells can provide a valuable tool for studying the molecular basis for differentiation of hepatocytes and form the basis for cell therapies. (HEPATOLOGY 2003;37:983-993.)