Aim: 

The aim of our study was evaluate the antiproliferative and, proapoptotic effects of a crude extract of polyphenols (CE), obtained from extra virgin olive oil on human promyelocitic leukaemia cell HL60/S HL60/R as sensitive and resistant variant (MDR phenotype).

Methods: 

The antiproliferative effect was evaluated on leukemia cells after incubation of the cells in the presence of various concentration of CE for 48 hours. Cells viability was assessed by trypan blue exclusion dye. The effects of CE on cell cycle was performed after a 24 hours treatment by flow cytometric analysis on cells stained with propidium iodide. The apoptosis was morphologically determined by fluorescent microscopy after labelling with orange acridine.

Results: 

Preliminary results showed that a crude extract of polyphenols has a similar dose–response antiproliferative effect on the HL60 as sensitive and resistant variant. The concentration of CE inhibiting the cellular growth by 50% was 7,5 mg/ml for sensitive HL60/S and 11,1 mg/ml for resistant HL60/R respectively. The cell cycle analysis showed arrest in G0/G1 in the sensitive lines and arrest in phase S in the resistant variant. The morphological analysis showed that CE was able to induce apoptosis on both sensitive and resistant cell lines.

Conclusion: 

Our data suggest that the CE was able to induce a citotoxic effect and apoptosis on both sensitive and resistant cell lines. Further studies are in progress to assess the mechanisms and the enzymes involved in the induction of apoptosis.