Effect of aqueous extract of Origanum vulgare on acute promyelocytic leukemia cell line (HL-60)

Acute promyelocytic leukemia is a malignancy of myeloid cells that are associated with resistance to apoptosis and differentiation arrest in promyelocytes in the bone marrow. The aim of this study was to investigate the effect of Origanum vulgare aqueous extract on apoptosis induction in an acute promyelocytic leukemia cell line (HL-60).

 The viability of HL-60 cells under treatment with various doses of Origanum vulgare extract was assessed by using a cell cytotoxic assay. Then, IC50 values​​ were determined after 24, 48, and 72 hours. The expression of Caspase8, Caspase9, Bax, Bcl2, and Nrf2 genes were measured by real-time PCR assay and different stages of apoptosis and necrosis in HL-60 cells were investigated using acridine orange/ethidium bromide double staining. Finally, data were introduced into SPSS software and analyzed by one-way ANOVA.

The results showed that Origanum vulgare extract decreased HL-60 cell survival and Caspase9, Caspase8, Bax, Bcl2, and Nrf2 gene expressions were changed after 72 hours of treatment with 1/5 of IC50 of Origanum vulgare extract. Also, morphological changes in the nucleus indicated apoptosis induction in HL-60 cells.

It seems that the aqueous extract of Origanum vulgare leaves can induce apoptosis in an acute promyelocytic leukemia cell line (HL-60) under experimental conditions.