The cytotoxic activity and apoptosis induction of 8-hydroxyisocapnolactone-2΄,3΄-diol (HICD) and its combination with doxorubicin (Doxo) on MCF-7 and T47D cells have been evaluated. The cytotoxic assay was performed using MTT method. The IC50 was used to express the cytotoxic potency, while the combination index (CI) was calculated to determine the effect of combination. The apoptotic assay was carried out using acrydine orange - ethidium bromide double staining method, while Bcl-2 and Bax expression were investigated by immunocytochemistry. The HICD exhibited cytotoxic activity on MCF-7 and T47D cells with the IC50 of 8 µg/ml (21.2 µM) and 4 µg/ml (10.6 µM), respectively. The combination of HICD with Doxo showed synergistic effect and increased apoptosis induction on both cell lines. The HICD did not affect Bcl-2 but increased Bax expression on MCF-7 cells, while on T47D cells it suppressed Bcl-2 expression but did not modulate Bax expression.
Key words: 8-Hydroxyisocapnolactone-2΄,3΄-diol, Cytotoxic activity, Apoptosis induction, Doxorubicin, MCF-7, T47D.