NSSR1 is regulated by testosterone in the mouse uterus and extensively expressed in endometrial carcinoma.

Neural salient serine/arginine-rich protein 1 (NSSR1) has been found to play important roles in inhibiting alternative splicing during heat shock and mitosis and is predominantly expressed in neural tissues such as cerebral neurons, cerebellar Purkinje cells and bipolar cells of the retina. Recently, NSSR1 has also been shown to be highly expressed in the testes, suggesting its potential roles in reproductive system. In this report, the expression of NSSR1 in the columnar epithelium of the endometrium and gland epithelium during the development of the mouse uterus, the regulation of NSSR1 level by testosterone in the adult mouse uterus, and expression level of NSSR1 in both human endometrial carcinomas and ovarian cancers were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemistry. We demonstrated that the expression of NSSR1 was developmentally regulated in the columnar epithelium of the endometrium and gland epithelium in the mouse uterus. Additionally, the NSSR1 level in the mouse uterus was maintained and regulated by testosterone. Interestingly, an enhanced level of NSSR1 was observed in both human endometrial carcinomas and ovarian cancers. Our results suggest that expression and distribution of NSSR1 is developmentally and hormonally regulated and up-regulated in endometrial carcinomas as well as ovarian cancers, indicating its potential involvement in uterine development and tumorgenesis.