Malignant gliomas are the most common primary intracranial tumors with a dismal prognosis. Previous investigations by our group demonstrated the radiosensitizing effect of silver nanoparticles (AgNPs) on glioma cells in vitro. The goal of the present study was to evaluate the efficacy of intratumoral administration of AgNPs in combination with a single dose of ionizing radiation at clinically relevant MV energies for the treatment of C6 glioma-bearing rats. AgNPs (10 or 20 μg/10 μl) were stereotactically administered on day 8 after tumor implantation. One day after AgNP injection, rats bearing glioma received 10 Gy radiation. The mean survival times were 100.5 and 98 days, the corresponding percent increase in life spans was 513.2% and 497.7%, and the cure rates were 41.7 and 38.5% at 200 days for the 10 and 20 μg AgNPs and radiation combination groups, respectively. In contrast, the mean survival times for irradiated controls, 10 and 20 μg AgNPs alone, and untreated controls were 24.5, 16.1, 19.4, and 16.4 days, respectively. Furthermore, a cooperative antiproliferative and proapoptotic effect was obtained when gliomas were treated with AgNPs followed by radiotherapy. Our results showed the therapeutic efficacy of AgNPs in combination with radiotherapy without apparent systemic toxicity, suggesting the clinical potential of AgNPs in improving the outcome of malignant glioma radiotherapy.

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Magnetically sensitive alginate-templated polyelectrolyte multilayer microcapsules were successfully synthesized by a novel process combining emulsification and layer-by-layer self-assembly techniques. The as-synthesized microcapsules (2.67 µm in diameter) were superparamagnetic with a saturation magnetization of 14.2 emu • g -1 , which contained approximately 30 wt % maghemite nanoparticles. The drug (doxorubicin) encapsulation efficiency was 56.4% and loading content was 3.5%. The in vitro release behavior under a high-frequency magnetic field (HFMF) indicated that the applied HFMF accelerated significantly the drug release from the microcapsules, which might be related to the microcapsules' magnetic properties. Moreover, the in vitro cytotoxicity of doxorubicin-loaded alginate-templated polyelectrolyte multilayer microcapsules and the doxorubicin released from the microcapsules were investigated.

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Tetrandrine is known to exert antitumor effect, however, little is known about its effect on nasopharyngeal carcinoma cells. In this study, we tested tetrandrine-induced apoptosis and radiosensitivity in nasopharyngeal carcinoma cell line CNE and investigated the possible mechanisms. Using flow cytometry and DNA electrophoresis, we found that tetrandrine could induce cell apoptosis. Further, it was shown that the level of Bcl-2 mRNA decreased and Bax mRNA increased after addition of tetrandrine by using reverse transcription-polymerase chain reaction. X-ray-induced G2 arrest was abrogated by treatment with tetrandrine, as detected by flow cytometry and mitotic index. The accumulation of cyclinB1 protein and the suppression of Cdc2 tyrosine-15 and Cdc25C serine-216 phosphorylation were detected in irradiated cells treated with tetrandrine using Western blot analysis. Taken together, these results show that tetrandrine can induce apoptosis and abrogate radiation-induced G2 arrest in CNE cells.

Magnetic nanoparticles (MNPs) can heat up tumor tissues and induce killing of cancer cells under external AC magnetic field. However, magnetic nanoparticles hyperthermia (MNPH) requires high concentration of MNPs that are injected into the tumor in order to obtain clinically needed thermal dose because of the complicated heat transfer in vivo and the limited heat quality of MNPs. To cut down the dose of MNPs and enhance the effect of this Nanotherapy, we prepared silver nanoparticles (AgNPs) with different sizes and investigated the effects of these AgNPs on cancer cells in MNPH treatment. It was found that AgNPs could enhance thermo-sensitivity of glioma cells and this effect was size dependent. AgNPs could induce cell cycles arrested in G 2 /M phase and enhanced the apoptosis rate of cancer cells after hyperthermia. In glioma bearing rats model, MNPH combined with AgNPs could enhance Bax expression in cancer cells. Our results suggested that AgNPs could be a potential thermo-sensitizer and could be further developed for the design of Ag nanostructurebased thermal seeds for MNPH therapy.

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