CHINESE MEDICINAL HERBS INHIBIT GROWTH OF MURINE RENAL-CELL CARCINOMA

Tumors are known to produce factors suppressing immune functions. We p reviously showed that a murine renal cell carcinoma (Renca) suppressed macrophage function in vitro and that this suppression was abolished by co-incubation with extracts of two Chinese medicinal herbs. We now report that these phytochemicals are capable of inhibiting growth of R enca in vivo. BALB/c mice were transplanted intraperitoneally (IP) wit h 1-2 x 10(5) Renca cells. One day after tumor transplant, mice were r andomized into two groups. One group was treated IP, daily for 10 days , with 100 mul of phytochemicals containing 500 mug each of Astragalus membranaceus and Ligustrum lucidum, while the other group received sa line as controls. A cure rate of 57% was obtained with these phytochem icals when the initial tumor load was 2 x 10(5) and 100% when the init ial tumor load was 1 x 10(5). Additional experiments were performed to investigate the mechanisms involved in this protection. Splenic macro phages from tumor-bearing mice were shown to have depressed chemilumin escent oxidative burst activity, and this depression was restored with phytochemical treatment. Splenocytes from mice transplanted with Renc a responded less favorably to interleukin-2 (IL-2) in generating lymph okine-activated killer (LAK) cells, again this depression was restored with phytochemical treatment. Our data suggest that these phytochemic als may have exerted their antitumor effects via augmentation of phago cyte and LAK cell activities.