Apoptotic cell death of human gastric tumor induced by nucleosides from CD57+HLA-DRbright natural suppressor cell line.

CD57+HLA-DRbright natural suppressor (57.DR-NS) cell line derived from human decidual tissue generated apoptosis in a human gastric carcinoma cell line (GCIY) but not in a human diploid normal cell line (WI-38). The factors released from 57.DR-NS cells were purified by thin-layer-chromatography (TLC) and separated by high performance liquid chromatography (HPLC) into six components. The physicochemical structures of the six components were determined as a series of nucleosides and their modified forms collectively termed <apoptosis inducing nucleosides (AINs)> in a previous study. They could generate apoptotic cell death of GCIY malignant target cells, but not disturb the viability of WI-38 normal target cells. The administration of AINs into GCIY tumor bearing SCID mice resulted in drastic suppression of tumor growth followed by the decrease in tumor size due to the occurrence of apoptosis in tumor tissues.