[Synergistic Induction of Apoptosis by Chemotherapeutic Drugs and Cytokines in Mouse T-Lymphoma Cell Line]

The objective of the study is to find out the synergistic effect on apoptosis resulting from the combination of chemotherapeutic drugs and some cytokines. Dexamethasone (DEX), etoposide (VP16), arsenic trioxide (As(2)O(3)) and alltrans-retinoic acid (ATRA) were added to the murine T lymphoma cell line RMA as well as to the cells preincubated with IL-2, IL-6 or GM-CSF, respectively. The effect on apoptosis was observed. All four chemotherapeutic drugs inhibited the cell proliferation. DEX, VP16 or As(2)O(3), except ATRA, singly induced apoptosis of RMA cells. The DEX concentration of inducing apoptosis was reduced when it was added together with ATRA. IL-2, IL-6 and GM-CSF did not induce apoptosis when the cytokines were added to RMA separately, however, apoptosis could be induced by combination of IL-2 and IL-6. The cytokines facilitated the apoptotic action of chemotherapeutic drugs, the drug concentration for inducing apoptosis decreased and the time period of starting apoptosis shortened. The results demonstrated that there was synergistic effect of chemotherapeutic drugs and some cytokines for induction of apoptosis. It raised an experimental basis for combination of chemotherapeutic drugs and some cytokines, especially IL-2, in the treatment of malignant lymphoma.