Study of the action of curcumin-nanoparticles in HPV-16 positive cervical carcinoma cells

The Human Papillomavirus (HPV) is a family of DNA viruses with more than 202 types, and are divided into high and low risk HPVs. High-risk HPV infection was identified as etiologic agent of six types of cancer, including cancer of the cervix, penis, vagina, vulva, anus, and oropharynx, and, approximately, 99.7% of the cases of cervical cancer are caused by high-risk HPV infections. Current treatment modalities for invasive carcinoma are the combination of cisplatinbased chemotherapy with radiation, however cisplatin shows severe adverse effects and a low survival rate. Therefore, ongoing efforts are necessary to developed news effective therapeutic strategies to enhance chemotherapeutic efficacy and decrease these side effects, maximizing the local response and patient survival. Curcumin is a bioactive versatile hydrophobic compound which has anti-inflammatory, anti-hyperlipidaemic, anti-angiogenic, anti-neoplastic and chemoprotective properties. Furthermore, curcumin may be used as a photosensitizing agent in Photodynamic Therapy. This study aimed to investigate the effects of Photodynamic Therapy in cellular viability using curcumin-nanoemulsion as photosensitizing drug in cervical carcinoma HPV- 16 cell lines and identify possible molecular changes. The absence of cytotoxicity of empty nanoemulsion showed its biocompatibility. Additionally, the incubation with curcumin-nanoemulsion at 20 μM of curcumin showed more than 80% of cell viability for cell lines. Nanoemulsions were internalized efficiently in cells and were observed in the intracellular environment for up 36 hours after incubation in SiHa cells and for 48 hours in CasKi cells by fluorescence microscopy. Besides, after the Photodynamic Therapy we observed high phototoxic effect of the curcumin-nanoemulsion with less than 5% of viable cells after irradiation. This was accompanied by an increase in caspase-3/7, suggesting cell death by apoptosis. We conclude that curcuminnanoemulsion formulation behaves as photosensitizing agent in Photodynamic Therapy and shows potential as an alternative treatment to cervical carcinoma. (AU)