[Study on the expression of nm23-M1/NDPK a during the blastocyst adhesiveness in the mouse endometrium]

The nm23 gene was originally identified as a metastasis suppressor gene by differential hybridization of non-metastatic and metastatic clones of murine K-1735 melanoma cell lines. Subsequently, other highly homologous genes were characterized and shown to code for nucleoside diphosphate kinase (NDPK) isotypes. These enzymes have been evidenced in a wide variety of organisms. In human, up to eight distinct but highly related genes have been discovered. The nm23-H1 and nm23-H2 gene products share 88% identity and are about 95% and 98% identical to the murine nm23-M1 and nm23-M2 proteins respectively. A number of data indicate that nm23 family, initially documented as metastasis suppressors in some cancer types, are involved in the control of normal development, differentiation and apoptosis. The trophoblast cells of blastocyst and of the normal first-trimester placenta share some phenotypic similarities with malignant cells, such as rapid proliferation and ability to invade neighbouring tissues, including basement membrane, during the process of implantation and placental development, but do not have the ability for unlimited growth or metastasis, as few trophoblast cells can be identified in the deciduas, and trophoblasts rarely penetrate the maternal blood vessels. Although some data indicate that nm23 family play an important role in regulation of reproductive processes, little is know about its actual mechanism. In our studies, we performed RT-PCR, Western blot and immunohistochemical analyses of nm23-M1/NDPK A expression during the blastocyst adhesiveness in the mouse endometrium. The nm23-M1 mRNA expression was shown progressive increase in D5 mice endometrium by RT-PCR, which was consistent with the result obtained by Western blot and immunohistochemistry. It is suggested that nm23-M1/NDPK A was involved in the process of blastocyst implantation.