EFFECT OF (-)-EPIGALLOCATECHIN GALLATE ON LEUKEMIC BLAST CELLS FROM PATIENTS WITH ACUTE MYELOBLASTIC-LEUKEMIA

Information on the anti-carcinogenic effect of EGCG, the main constitu ent of the polyphenols present in Japanese green tea leaves, has recen tly been accumulating. In this report, we evaluate the effect of EGCG on leukemic blast cells from AML patients. The results showed that EGC G inhibited the proliferation of AML cells in all cases examined. Sinc e AML cells might proliferate by autocrine or paracrine growth mechani sms, we also examined the effect of EGCG on the production of GM-CSF f rom AML cells. Although EGCG did not directly inhibit the production o f GM-CSE it did inhibit the effect of TNF-alpha or TPA, both of which stimulated AML cells to produce GM-CSEF. On the other hand, the modula tion of receptors for growth factors might play a role in the prolifer ation or carcinogenesis of AML cells. We also found that ECCG inhibite d the modulation of c-kit, a receptor for stem cell factor, on leukemi c cells. These findings suggested that EGCG might be available as a ne w therapeutic tool for AML patients.