Background/aimIn this study we investigated the effect of DOX and five of its derivatives containing a formamidine group (NCHNRR) at the 3′ position with pyrrolidine (DOX-F PYR), piperidine (DOX-F PIP), morpholine (DOX-F MOR), N-methylpiperazine (DOX-F PAZ) and hexamethyleneimine (DOX-F HEX) ring on SKOV-3 ovarian cancer cells. We have focused on the anti-proliferative activity and the value of apoptosis induced by tested analogues. Materials and methodsThe following methods were used: spectrophotometric assay with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide); fluorimetric assays – double staining with Hoechst 33258 and propidium iodide (PI), measurement of caspase-3 activity; flow cytometry methods – phosphatidylserine (PS) externalization using Annexin V-FITC and PI fluorochromes, and TUNEL assay. ResultsAll of the investigated derivatives were considerably more cytotoxic to the SKOV-3 cell line than DOX. The predominant type of cell death induced by the anthracycline analogues was apoptosis. Necrotic cells represented only a small percentage (<5%) of all cells. The number of apoptotic cells was dependent on the compound and the incubation time. Moreover, a significant increase in caspase-3 activity, DNA fragmentation, and morphological changes in ovarian cells were observed predominantly in new DOX analogues. ConclusionsAll new formamidine derivatives of DOX were effective against ovarian cancer cells. They induced mainly the apoptotic pathway of cell death mediated by caspase-3. The most promising results were obtained for DOX-F MOR and DOX-F PAZ. The least potent was DOX-F HEX.