Cysteine produced from lymph node stromal cells suppresses apoptosis of mouse malignant T-lymphoma cells.

Mouse malignant T-lymphoma CS-21 cells can grow when cocultured with CA-12 lymph node stromal cells, but they undergo apoptotic cell death with DNA fragmentation when separated from CA-12 stromal cells. In the course of examining the effects of the soluble factor(s) secreted by CA-12 stromal cells on CS-21 cell growth, we found that cysteine produced from CA-12 stromal cells promoted CS-21 cell growth and suppressed apoptosis in the isolated culture of CS-21 cells. The expression of anti-apoptotic protein Bcl-2, however, was not induced by cysteine. These results indicate that cysteine produced from CA-12 stromal cells participates not only in the cell growth but also in the inhibition of CS-21 apoptosis without inducing the expression of Bcl-2 protein.