Evaluation of synergistic effects of sulforaphene with photodynamic therapy in human cervical cancer cell line.

Sulforaphene from cruciferous vegetable has shown to modulate various signaling pathways of apoptosis. But it has not yet been studied extensively for the cervical cancer treatment. Previous studies show the promising role of photodynamic therapy for cervical cancer. Here, we confirm that sulforaphene can synergistically enhance the efficacy of photodynamic therapy. Human cervical cancer cells HeLa were treated with a very low dose of sulforaphene (2.0 μg/ml) and photodynamic therapy with radachlorin (0.5 μg/ml) at a fluence of 27 J/cm2 (30 milliwatts/cm2, λmax ∼ 670 ± 3 nm). The combination treatment showed a synergistic effect to induce apoptosis. The mitochondrial apoptotic pathway was activated via caspase 3 and caspase 9. On the other hand, caspase 12 and C/EBP homologous protein (CHOP) were expressed that indicated endoplasmic reticulum stress. This combination treatment also activated death receptor pathway via activation of caspase 8 and inhibited cell proliferation via down-regulation of EGFR. Thus, several apoptotic pathways were simultaneously activated in this combination treatment which results in a synergistic efficacy of sulforaphene with photodynamic therapy. Therefore, this study could be useful in the improvement of therapies for human cervical and other types of cancers.