Aesculetin (6,7-dihydroxycoumarin) exhibits potent and selective antitumor activity in human acute myeloid leukemia cells (THP-1) via induction of mitochondrial mediated apoptosis and cancer cell migration inhibition.

PURPOSE

The main target of the present research was to examine the antitumor properties of aesculetin in human acute myeloid leukemia cancer cells (THP-1) and peripheral blood mono-nucleated cells (PBMCs) (used as normal cell line model) along with the determination of its effects on induction of apoptosis, inhibition of cancer cell migration and changes in Bcl-2/Bax protein expressions.

METHODS

MTT colorimetric bioassay was performed to study the impact of this natural compound on cytotoxicity of both cell types. Moreover, transmission electron microscopy (TEM), inverted phase contrast and fluorescence microscopic techniques were used to study the effects on cell morphology and cellular ultrastructural details connected with apoptosis. The effects of aesculetin on Bcl-2/Bax protein expressions were assessed by Western blot method.

RESULTS

Selective and dose-dependent antiproliferative activity of aesculetin in human acute myeloid leukemia cancer cells was observed. However, the compound did not induce significant cell growth inhibition of PBMCs, which were used as normal cell controls. Fluorescence and inverted phase contrast microscopic techniques revealed that aesculetin led to morphological changes suggestive of apoptosis (cell shrinkage, chromatin abridgment and membrane blebbing). TEM analysis showed that aesculetin led to fragmented plasma membrane along with appearance of spherical projections (apoptotic bodies). The wound scratch widened after aesculetin treatment, indicating that aesculetin exhibits anticancer effects by suppressing the cancer cell migration. Aesculetin led to significant and dose-dependent reduction in the Bcl-2 expression while the expression of Bax was significantly enhanced resulting in overall reduction of Bcl-2/Bax ratio.

CONCLUSION

The results of the present work revealed that aesculetin exhibits selective anticancer effects in THP-1 human leukemia cells without causing much cytotoxicity in PBMCs. It also led to significant apoptosis induction, inhibition of cancer cell migration and decrease in Blc-2/Bax ratio.