PROPOLIS OR CAFFEIC ACID PHENETHYL ESTER (CAPE) INHIBITS GROWTH AND VIABILITY IN MULTIPLE ORAL CANCER CELL LINES.

Abstract

Objective: Propolis is a natural antimicrobial resin from honeybee hives that contains caffeic acid phenethyl ester (CAPE), which has anti-proliferative activity against some human cancers, including colon, liver, lung and breast – although limited evidence has evaluated this potential in oral cancers. Based upon this information, the primary objective of this study was to evaluate the anti-tumor effects of CAPE against multiple well-characterized oral cancer cell lines. Methods: Using well-characterized oral cancer cell lines (SCC15, SCC25 and CAL27), CAPE was administered at 100 ug/mL to assess any effects on cellular viability or growth over three days. A normal, non-cancerous cell line (HGF-1) was also included. Results: The results of this pilot study demonstrated that CAPE administration significantly reduced both viability and proliferation in all three oral cancer cell lines.  Viability was significantly reduced between 30.3% and 35.4% among the oral cancer cell lines (p<0.05), but remained unchanged in the HGF-1 normal cell control (p=0.878). Growth was significantly inhibited between 53.1% and 60.6% among the oral cancer cell lines (p<0.05) but was not affected in the HGF-1 normal cell control (p=0.341). Conclusions: Although the reductions in both cellular viability and proliferation were distinct for each cell line, all exhibited a similar trend and were within a narrowly defined range. These results strongly suggest that CAPE administration had a significant and immediate effect on oral cancer growth and viability and therefore should be considered as the basis for future studies as a potential complementary and alternative therapy for oral cancer. Key words: Caffeic Acid Phenethyl Ester (CAPE), Propolis, Oral cancer, Complementary and alternative medicine.