Gold nanorods and curcumin-loaded nanomicelles for efficient in vivo photothermal therapy of Barrett's esophagus.

AIM: Provide an enhanced local drug delivery, nanoparticle(s) to minimize systemic effects and achieve enhanced permeability and drug retention into abnormal cells and stroma. MATERIALS & METHODS: Here a simultaneous loading of lipophilic gold nanorods (GNRs) and curcumin into polymeric nanomicelles made of biocompatible PLGA-b-PEG copolymer through a double re-emulsification process has been developed. RESULTS: Initial results in vitro on Barrett's esophagus and esophageal adenocarcinoma cell lines demonstrated a significant reduction in cell viability with curcumin and GNRs exposure (p < 0.05). In vivo Barrett's-associated animal model confirmed these results with successful in vivo demonstrated eradication of all high-grade dysplastic premalignant cancer cells. CONCLUSION: The synthesis of this novel nanosystem containing GNRs and curcumin is safe and effective in treating and eradicating premalignant esophageal adenocarcinoma.

Synergistic effects of cisplatin chemotherapy and gold nanorod-mediated hyperthermia on ovarian cancer cells and tumors.

AIM: The synergistic effects of gold nanorod (GNR)-mediated mild hyperthermia (MHT; 42-43°C) and cisplatin (CP) activity was evaluated against chemoresistant SKOV3 cells in vitro and with a tumor xenograft model. MATERIALS & METHODS: In vitro studies were performed using CP at cytostatic concentrations (5 µM) and polyethylene glycol-stabilized GNRs, using near-infrared laser excitation for MHT. RESULTS: The amount of polyethylene glycol-GNRs used for environmental MHT was 1 µg/ml, several times lower than the loadings used in tumor tissue ablation. GNR-mediated MHT increased CP-mediated cytotoxicity by 80%, relative to the projected additive effect, and flow cytometry analysis suggested MHT also enhanced CP-induced apoptosis. In a pilot in vivo study, systemically administered polyethylene glycol-GNRs generated sufficient levels of MHT to enhance CP-induced reductions in tumor volume, despite their heterogeneous distribution in tumor tissue. CONCLUSION: These studies imply that effective chemotherapies can be developed in combination with low loadings of nanoparticles for localized MHT. Original submitted 6 July 2013; Revised submitted 20 October 2013.

[Environmental air pollutants and the risk of cancer].

The increased combustion of fossil fuels is one of the main reasons for the hazardous changes in the atmospheric composition. The sources of air pollution in urban areas include diesel motor vehicles, residential wood burning, and certain industrial processes. The types of air pollution include gases(eg, carbon monoxide, sulfur dioxide, nitrogen oxides, ozone)and suspended particulate matter(PM)such as PM2.5 and PM10 in diesel exhaust particles. PM2.5 refers to particles less than 2.5 micrometers in diameter. Long-term exposure to PM2.5 can increase the cardiovascular disease risk and lung cancer mortality. Although the role of PM2.5 in the etiology of lung cancer is not very clear, some researchers have shown evidence of increases in lung cancer mortality associated with exposure to PM2.5. Asbestos is also an important cause of cancer of the respiratory tract, particularly lung cancer and mesothelioma. The oncogenic hazards of asbestos fiber have been noted in cases of lowdose environmental exposure, as well in cases of high-dose occupational exposure. The use of asbestos has been strictly prohibited in Japan since 2006. However, large-scale natural disasters such as earthquakes, tsunamis, and typhoons can destroy many buildings and houses that were constructed before the ban on asbestos was initiated, thus resulting in the exposure of human beings to asbestos fibers. In the Cappadocian villages of Tuzkoy, Karain, and Sarihidir in Turkey, 50% of all deaths among villagers are caused by mesothelioma. This condition has been attributed to exposure to erionite, which is a type of fibrous zeolite mineral commonly found in this area of Turkey. However, pedigree studies of these villages showed that mesothelioma was prevalent in certain families but not in others, and that erionite exposure typically causes mesothelioma in those with a genetic predisposition to this disease. Recently, the germline BAP1 mutation was demonstrated in 2 different familial clusters of mesothelioma in the US.

Photothermal therapy in a murine colon cancer model using near-infrared absorbing gold nanorods.

The photothermal ablation of solid tumors using exogenous, near-infrared (NIR)-absorbing nanoparticles has been previously investigated using various preclinical models and is currently being evaluated in the clinic. Here, we evaluate the circulation kinetics, preliminary toxicity, and efficacy of photothermal ablation of solid tumors using gold nanorods systemically delivered and passively accumulated in a murine subcutaneous colon cancer model. Tumored animals were infused with nanorods followed by the percutaneous illumination of the tumor with an 808-nm laser. Control groups consisted of laser-only, nanorod-only, and untreated tumored animals. The survival of the treated and control groups were monitored for 60 days post-treatment. The survival of the photothermally treated group was statistically longer than the control groups, with approximately 44% tumor free through the evaluation period. Histopathology of the major organs of animals infused with nanorods did not indicate any significant toxicity at 60 days post-treatment. Particle biodistribution was evaluated by elemental analysis of the major organs of untumored mice at 1, 7, and 30 days after infusion with nanorods. Elemental analysis indicates nanorod clearance from the blood and retention by the reticuloendothelial system. This study indicates that gold nanorods are promising agents for photothermal ablation of solid tumors.

Cytotoxicity suppression and cellular uptake enhancement of surface modified magnetic nanoparticles.

The aim of this study was to modify the surfaces of superparamagnetic iron oxide nanoparticles (SPION) with pullulan in order to reduce the cytotoxicity and enhance the cellular uptake of the nanoparticles. In this study, we have prepared and characterised the pullulan coated superparamagnetic iron oxide nanoparticles (Pn-SPION) of size around 40-45 nm with magnetite inner core and hydrophilic outer shell of pullulan. We have investigated the effect of cellular uptake of uncoated and Pn-SPION on cell adhesion/viability, cytotoxicity, morphology and cytoskeleton organisation of human fibroblasts. Cell cytotoxicity/adhesion studies of SPIONs on human dermal fibroblasts showed that the particles are toxic and their internalisation resulted in disruption of cytoskeleton organisation of cells. On the other hand, Pn-SPIONs were found to be non-toxic and induced changes in cytoskeleton organisation different from that observed with SPION. Transmission electron microscopy results indicated that the SPION and Pn-SPION were internalised into cells via different mechanisms, thereby suggesting that the particle endocytosis behaviour is dependent on the surface characteristics of the nanoparticles.