The honeybee hive product, propolis, is a folk medicine employed for treating various ailments. Many important pharmaceutical properties have been ascribed to propolis, including anti-inflammatory, antiviral, immunostimulatory and carcinostatic activities. Propolis extracts have provided an active component identified as caffeic acid phenethyl ester (CAPE), which was readily prepared in one step. Differential cytotoxicity has been observed in normal rat/human versus transformed rat/human melanoma and breast carcinoma cell lines in the presence of CAPE.

Mutations in the Adenomatous Polyposis Coli (APC) tumor suppressor gene or the beta-catenin gene are present in most colon cancers and less frequently in other tumor types. In this study, we screened 24 human breast cancer cell lines and three immortalized human breast epithelial cell lines for alterations in beta- and gamma-catenin and APC by western blotting, protein truncation assay and DNA sequence analysis. In one cell line (DU 4475), an APC mutation was identified (E1577stop) that resulted in expression of truncated APC. This mutation was associated with elevated cytosolic beta-catenin levels, probably due to loss of APC function, as in colon cancers. No mutations were found in exon 3 of the beta- or gamma-catenin genes. We conclude that APC mutations and beta-catenin upregulation may occur with low frequency in human breast cancer cells.

Mutations in the Adenomatous Polyposis Coli (APC) tumor suppressor gene or the beta-catenin gene are present in most colon cancers and less frequently in other tumor types. In this study, we screened 24 human breast cancer cell lines and three immortalized human breast epithelial cell lines for alterations in beta- and gamma-catenin and APC by western blotting, protein truncation assay and DNA sequence analysis. In one cell line (DU 4475), an APC mutation was identified (E1577stop) that resulted in expression of truncated APC. This mutation was associated with elevated cytosolic beta-catenin levels, probably due to loss of APC function, as in colon cancers. No mutations were found in exon 3 of the beta- or gamma-catenin genes. We conclude that APC mutations and beta-catenin upregulation may occur with low frequency in human breast cancer cells.

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