3-Chloro-2,5-dihydroxybenzyl alcohol activates human cervical carcinoma HeLa cell apoptosis by inducing DNA damage

We have isolated 3-chloro-2,5-dihydroxybenzyl alcohol (CHBA) from marine-derived fungus Aspergillus sp. and characterized its apoptosis-inducing properties against human cervical carcinoma (HeLa) cells. Significantly decreased rates of proliferation and viability (IC50 approximately 35 microM) as well as evidence of apoptosis were observed with CHBA. Nuclear changes observed under fluorescence microscopy confirmed apoptosis occurrence and showed a typical pattern of chromatin condensation. Furthermore, results from Annexin V-FITC/PI dual staining indicated that CHBA induced earlier apoptosis of HeLa cells in a concentration- and time-dependent manner. CHBA also induced cytochrome c release from mitochondria into the cytosol and subsequent caspase activation involving caspase-9 and -3 by Western blotting assay was observed. We also found that CHBA was able to induce DNA damage and inhibit DNA replication followed by S phase arrest. The very sensitive alkaline microgel electrophoresis technique (comet assay) was used for estimation of the CHBA-induced DNA single strand breaks. These findings suggest that CHBA induces HeLa cell apoptosis by cytochrome c release and caspase activation pathway and that the effect of CHBA on apoptosis of HeLa cells is associated with DNA damage. Because of the ease of synthesis and structural manipulation, CHBA may have the potential to be developed into an anticancer agent.