OBJECTIVES:Curcumin, a natural pigment from the traditional Chinese herb, has shown promise as an efficient enhancer of ultrasound. The present study aims to investigate ultrasound-induced cellular destruction of nasopharyngeal carcinoma cells in the presence of curcumin in vitro.

METHODS:Nasopharyngeal carcinoma cell line CNE2 cells were incubated by 10μm curcumin and then were treated by ultrasound for 8s at the intensity of 0.46W/cm(2). Cytotoxicity was evaluated using MTT assay and light microscopy. Mitochondrial damage was analyzed using a confocal laser scanning microcopy with Rhodamine 123 and ultrastructural changes were observed using a transmission electron microscopy (TEM).

RESULTS:MTT assay showed that cytotoxicity induced by ultrasound treatment alone and curcumin treatment alone was 18.16±2.37% and 24.93±8.30%, respectively. The cytotoxicity induced by the combined treatment of ultrasound and curcumin significantly increased up to 86.67±7.78%. TEM showed that microvillin disappearance, membrane blebbing, chromatin condensation, swollen mitochondria, and mitochondrial myelin-likebody were observed in the cells treated by ultrasound and curcumin together. The significant collapse of mitochondrial membrane potential (MMP) was markedly observed in the CNE2 cells after the combined treatment of curcumin and ultrasound.

CONCLUSIONS:Our findings demonstrated that ultrasound sonication in the presence of curcumin significantly killed the CNE2 cells and induced ultrastructural damage and the dysfunction of mitochondria, suggesting that ultrasound treatment remarkably induced cellular destruction of nasopharyngeal carcinoma cells in the presence of curcumin.

Objectives. Curcumin, a natural pigment from a traditional Chinese herb, has been attracting extensive attention. The present study aims to investigate cell death of nasopharyngeal carcinoma (NPC) cells induced by ultrasound sonication in the presence of curcumin in vitro. METHODS: The NPC cell line CNE2 was chosen as a tumor model, and curcumin concentration was kept constant at 10 muM while the cells were subjected to ultrasound exposure for 8 s at an intensity of 0.46 W/cm(2). Cell death was evaluated using flow cytometry with annexinV-FITC and propidium iodine staining, and nuclear staining with Hoechst 33258. Mitochondrial membrane potential and intracellular reactive oxygen species (ROS) were analyzed using flow cytometry with rhodamine 123 and dichlorodihydrofluorecein diacetate staining. RESULTS: Flow cytometry showed that the combination of ultrasound and curcumin significantly increased the necrotic or late apoptotic rate by up to 31.37% compared with the controls. Nuclear condensation was observed in the nuclear staining, and collapse of DeltaPsim and ROS increase were found in the CNE2 cells after the treatment with curcumin and ultrasound. CONCLUSIONS: The findings demonstrate that the presence of curcumin significantly enhances the ultrasound-induced cell death and ROS level, and induces the collapse of DeltaPsim, suggesting that ultrasound sonication can increase the cell death of NPC cells in the presence of curcumin and that the treatment using curcumin and ultrasound together is a potential therapeutic modality in the management of malignant tumors.

Norovirus (NoV) is one of the most important seafood- and water-borne viruses, and is a major cause of acute gastroenteritis outbreaks. In the present study we investigated the effect of curcumin as a sensitizer to photodynamic treatment both in buffer and in oysters against murine norovirus 1 (MNV-1), a surrogate of NoV. MNV-1 cultured in buffer and MNV-1 bio-accumulated in oysters were irradiated with a novel LED light source with a wavelength of 470nm and an energy of 3.6J/cm(2). Inactivation of MNV-1 was investigated by plaque assays. After virus was extracted from the gut of oysters treated over a range of curcumin concentrations, the ultrastructural morphology of the virus was observed using electron microscopy, and the integrity of viral nucleic acids and stability of viral capsid proteins were also determined. Results showed that the infectivity of MNV-1 was significantly inhibited by 1-3 log PFU/ml, with significant damage to viral nucleic acids in a curcumin dose-dependent manner after photodynamic activation. Virus morphology was altered after the photodynamic treatment with curcumin, presumably due to the change of the viral capsid protein structures. The data suggests that treatment of oysters with photodynamic activation of curcumin is a potentially efficacious and cost-effective method to inactivate food-borne NoV. Further studies are necessary to evaluate the toxicology of this approach in detail and perform sensory evaluation of the treated product.

Curcumin (Cur) is a promising antioxidant and anticancer drug, but several recent studies indicate that Cur exerts its anticancer activity through promoting reactive oxygen species (ROS) generation. In the present study, concentration-dependent regulation of Cur on cell proliferation, viability and ROS generation, and effect of water-soluble antioxidants ascorbic acid (ASA), N-acetyl-cysteine (NAC) and reduced glutathione (GSH) on the antioxidant and anticancer activity of Cur were investigated in human myeloid leukemia cells (HL-60 cells). We found that although Cur concentration- and time-dependently decreased the proliferation and viability of cells, its effect on ROS generation (as indicated by the level of malondialdehyde, MDA) varied with its concentrations. I.e., low concentrations of Cur diminished the ROS generation, while high Cur promoted it. Combined with the opposite effect of 50 microM H2O2 on low or high Cur-induced MDA alteration, cell proliferation arrest and cell death, these results proved that low Cur exerted its anticancer activity through diminishing ROS generation in HL-60 cells, while high Cur through promoting ROS generation. Further studies showed that all water-soluble antioxidants ASA, NAC and GSH significantly enhanced both the antioxidant and the anticancer activity of low Cur. Considering that the extra accumulation of ROS is harmful to normal cells, the data presented here indicate that instead of using high doses, combining low doses of Cur with water-soluble antioxidants is a better strategy for us to improve the anticancer activity of Cur.