B-cell leukemia protein-2 and peptide YY chemotherapy resistance in colon cancer

Background: Inhibition of apoptosis may allow cells with drug-induced damage to escape programmed cell death. The bcl-2 protein inhibits apoptosis and bcl-2 overexpression has been associated with drug resistance. It is our hypothesis that higher levels of bcl-2 expression will be seen in colon cancer cells resistant to PYY treatment. Methods: Caco2 and HCT116 colon cancer cells were treated with 2 μM PYY for 24 hours. Protein was extracted from cells surviving PYY treatment; bcl-2 expression was measured by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blotting. Results: Caco2 and HCT116 cells surviving PYY treatment demonstrated increased bcl-2 from 20.54 ± 2.7 to 28.63 ± 2.20 units/mL (P <0.05) and 21.98 ± 1.28 to 29.32* ± 2.26 units/mL, respectively. Conclusions: Increased expression of bcl-2 is seen in a population of colon cancer cells resistant to PYY. Hence, bcl-2 may protect neoplastic cells from apoptosis; its levels may be useful in predicting chemotherapy response and in selecting appropriate drug regimens.