Published in Cancer Detection and Prevention 1995; 19(1).

Susceptibility of propolis-treated tumor cells to human natural killer cell activity in vitro

M Ghoneum, O Mermel, L Williams, N Attallah & Y Hashimoto¹

The present study examines susceptibility of Propolis-treated tumor cells to Natural Killer (NK) cell cytotoxicity. Propolis is a resinous substance collected from plants by bees who use it to line hives and fill cracks. Two human tumor cell lines were used in the study: K562, an erythroblastoma which is NK sensitive, and Raji, a Burkitt's cell lymphoma which is NK resistant. Tumor cells were treated with 0.1 mg/ml Propolis for 3 days. Activity of NK-PBL obtained from 10 healthy control subjects was examined against both tumor cell lines using standard (51)Cr-release assay at a ratio of 50:1. Results showed that both tumor cell lines became more sensitive to NK cytotoxicity post treatment with Propolis. K562 cell lysis increased from 37.9% to 57.0% for control and Propolis treated cells respectively, representing a 33.5%, +/- 12.0% increase in lysis. Interestingly, Raji cells became even more susceptible to NK cells after Propolis treatment, with an 81.6%, +/- 8.7% increase in lysis. The increase in tumor cell susceptibility to NK cytotoxicity post treatment with Propolis may represent one mechanism by which Propolis exerts its anti-cancer activity.

Paper presented at the International Symposium on the Impact of Biotechnology on Predictive Oncology and Therapy; Boston, Massachusetts; December 11 - 13, 1994; in the section on Diagnostic Techniques.

http://www.cancerprev.org/Journal/Issues/19/1/309/1207