Radiotherapy performs an important function in the treatment of cancer, but resistance of tumor cells to radiation still remains a serious concern. More research on more effective radiosensitizers is urgently needed to overcome such resistance and thereby improve the treatment outcome. The goal of this study was to evaluate and compare the radiosensitizing efficacies of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) on glioma at clinically relevant megavoltage energies. Both AuNPs and AgNPs potentiated the in vitro and in vivo antiglioma effects of radiation. AgNPs showed more powerful radiosensitizing ability than AuNPs at the same mass and molar concentrations, leading to a higher rate of apoptotic cell death. Furthermore, the combination of AgNPs with radiation significantly increased the levels of autophagy as compared with AuNPs plus radiation. These findings suggest the potential application of AgNPs as a highly effective nano-radiosensitizer for the treatment of glioma.

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Metallic nanostructures as excellent candidates for nanosensitizers have shown enormous potentials in cancer radiotherapy and photothermal therapy. Clinically, a relatively low and safe radiation dose is highly desired to avoid damage to normal tissues. Therefore, the synergistic effect of the low-dosed X-ray radiation and other therapeutic approaches (or so-called "combined therapeutic strategy") is needed. Herein, we have synthesized hollow and spike-like gold nanostructures by a facile galvanic replacement reaction. Such gold nanospikes (GNSs) with low cytotoxicity exhibited high photothermal conversion efficiency (η = 50.3%) and had excellent photostability under cyclic near-infrared (NIR) laser irradiations. We have demonstrated that these GNSs can be successfully used for in vitro and in vivo X-ray radiation therapy and NIR photothermal therapy. For the in vitro study, colony formation assay clearly demonstrated that GNS-mediated photothermal therapy and X-ray radiotherapy reduced the cell survival fraction to 89% and 51%, respectively. In contrast, the cell survival fraction of the combined radio- and photothermal treatment decreased to 33%. The synergistic cancer treatment performance was attributable to the effect of hyperthermia, which efficiently enhanced the radiosensitizing effect of hypoxic cancer cells that were resistant to ionizing radiation. The sensitization enhancement ratio (SER) of GNSs alone was calculated to be about 1.38, which increased to 1.63 when the GNS treatment was combined with the NIR irradiation, confirming that GNSs are effective radiation sensitizers to enhance X-ray radiation effect through hyperpyrexia. In vivo tumor growth study indicated that the tumor growth inhibition (TGI) in the synergistically treated group reached 92.2%, which was much higher than that of the group treated with the GNS-enhanced X-ray radiation (TGI = 29.8%) or the group treated with the GNS-mediated photothermal therapy (TGI = 70.5%). This research provides a new method to employ GNSs as multifunctional nanosensitizers for synergistic NIR photothermal and X-ray radiation therapy in vitro and in vivo.

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The role of histone deacetylases (HDACs) in lung cancer has been extensively studied. Inhibition of HDAC activities have been used as a new cancer treatment strategy. To date, many HDAC inhibitors have been shown to induce apoptosis and inhibit tumorigenesis. Chidamide (CS055) is a new member of HDAC inhibitors. In China, Chidamide has been approved for the treatment of relapsed or refractory peripheral T-cell lymphoma. However, the efficacy of Chidamide in non-small cell lung cancer remains unclear. In this study, we used lung cancer primary cells and investigated the effects of Chidamide combined with paclitaxel on lung cancer. We found that Chidamide combined with paclitaxel effectively inhibited the expression and activity of HDAC in primary lung cancer cells, induced their apoptosis and blocked cell cycle. Chidamide combined with paclitaxel may therefore provide a new promising therapeutic treatment for lung cancer.