Gold Nanocage-Based Multifunctional Nanosensitizers for Programmed Photothermal /Radiation/Chemical Coordinated Therapy Guided by FL/MR/PA Multimodal Imaging

Background

Radiotherapy is one of the main clinical methods for the treatment of malignant tumors at present. However, its application is limited by the radiation resistance of some tumor cells and the irradiation damage to the surrounding normal tissues, and the limitation of radiotherapy dose also affects the therapeutic effect. Therefore, developing diagnostic and therapeutic agents with imaging and radiosensitizing functions is urgently needed to improve the accuracy and efficacy of radiotherapy.

Materials and Strategy

Herein, we synthesized multifunctional nanotheranostic FRNPs nanoparticles based on gold nanocages (GNCs) and MnO2 for magnetic resonance (MR)/photoacoustic (PA) imaging and combined photothermal, radiosensitive and chemical therapy. A programmed therapy strategy based on FRNPs is proposed. First, photothermal therapy is applied to ablate large tumors and increase the sensitivity of the tumor tissue to radiotherapy, then X-ray radiation is performed to further reduce the tumor size, and finally chemotherapeutic agents are used to eliminate smaller residual tumors and distant metastases.

Results

As revealed by fluorescence, MR and PA imaging, FRNPs achieved efficient aggregation and retention at tumor sites of mice after intravenous injection. In vivo studies have shown that the programmed treatment of FRNPs-injected nude mice which were exposed to X-ray after 808 laser irradiation achieved the greatest inhibition of tumor growth compared with other treatment groups. Moreover, no obvious systemic toxicity was observed in all groups of mice, indicating the good biocompatibility of FRNPs and the safety of the treatment scheme.

Conclusion

To sum up, our work not only showed a new radiosensitizer, but also provided a promising theranostic strategy for cancer treatment.

Etodolac enhances the radiosensitivity of irradiated HT-29 human colorectal cancer cells

BACKGROUND

Radioresistance is found to be the main therapeutic restriction in colorectal radiation therapy. The aim of this study was to investigate the synergistic effect of Etodolac (ET) and ionizing radiation on human colorectal cancer cells.

MATERIALS & METHODS

Pretreated HT-29 cells with ET were exposed to ionizing radiation. The radiosensitizing effect of ET was evaluated using MTT, flow cytometry and clonogenic assay. The amount of nitrite oxide (NO) in irradiated cells was also measured with Griess reagent.

RESULTS

The present study found that pretreatment of HT-29 cells with ET decreases their survival and colony formation. Higher concentrations of ET cause total apoptosis and an increase in NO levels in irradiated cells.

CONCLUSION

Applying ET in a concentration-dependent manner had an incremental effect on the amount of apoptosis and cell death induced by radiation.

The Radiosensitizing Effect of Olanzapine as an Antipsychotic Medication in Glioblastoma Cell

BACKGROUND

Radiotherapy is used as one of the most effective regimens for cancer treatment, while radioresistance is a major drawback in cancer treatment.

OBJECTIVES

The aim of this study was to evaluate the sensitizing effect of olanzapine (OLA) with X-ray on glioblastoma (U-87 MG) cells death.

METHODS

The synergistic killing effect of OLA with ionizing radiation (IR) on glioma was evaluated by colony formation assay. The generations of reactive oxygen species (ROS) and protein carbonyl (PC) as oxidized protein were determined in OLA and irradiated cells.

RESULTS

The results of this study showed that OLA reduced the number of colonies in irradiated glioma cells. OLA elevated ROS and PC levels in irradiated cells. The synergistic killing effect of OLA with IR in U-87 MG cell was observed at concentrations 1 µM and 20 µM of OLA. The maximum radiosensitizing effect of OLA was observed at concentration of 20 µM.

CONCLUSION

The present study demonstrates that OLA has radiosensitizing effect on cell death induced by IR in glioma cells.

Evaluation of the Radiosensitizing Potency of Bromelain for Radiation Therapy of 4T1 Breast Cancer Cells

Breast cancer (BC) remains the leading cause of death in women worldwide, despite the improvements of cancer screening and treatment methods. Recently, development of novel anticancer drugs for the improved prevention and treatment of BC is in the center of research. The anticancer effects of bromelain, as enzyme extract derived from the pineapples, contains chemicals that interfere with the growth of tumor cells. The aim of this study was to evaluate the effect of radiosensitizing of bromelain in 4T1 BC cells. This investigation utilized the 3-(4,5-dimethylthiazol-2-yl)-2,5-dimethyltetrazolium bromide assay to characterize the cytotoxicity of bromelain. Colony formation method was used to establish the truth of the capability of bromelain to make sensitive to radiation therapy. Flowcytometry performed to define the contribution the apoptosis effect to bromelain mediated radiosensitization of 4T1 cells. Bromelain reduced growth and proliferation of 4T1 cell as a concentration-dependence manner significantly. The survival of 4T1 cancer cells was decreased after combined treatment in a number and size-dependent manner with regard to the control group (P < 0.05). Combination of bromelain with radiation does not influence 4T1 cell apoptosis. The results suggested that bromelain can inhibit the growth and proliferation and reduce survival of 4T1 BC cells and might be used as a candidate radiosensitizer in BC patient.

Luminescent ruthenium(II) polypyridyl complexes acted as radiosensitizer for pancreatic cancer by enhancing radiation-induced DNA damage

Background: Pancreatic cancer is a highly lethal malignancy which ranks 4th most common cause of cancer death in US and 6th in China. Novel drugs are required to improve the survival and prognosis of patients. Methods: Ruthenium(II) complexes with variation number of DIP ligand were synthesized and further adopted as radiosensitizer for pancreatic cancer. The influence of ruthenium(II) complexes on cell behaviors and tumor growth were investigated. The DNA binding affinity of ruthenium(II) complexes and plasmid was measured by using agarose gel electrophoresis. Results: Luminescent ruthenium(II) complex can rapidly enter into cell nuclei and consequently combine with DNA, resulting in the enhanced DNA damage induced by X-ray irradiation. Upon intratumoral injection of ruthenium(II) complex, excellent tumor growth inhibition was accomplished under ionizing radiation of human pancreatic cancer xenograft nude mice. Conclusions: Taken together, our study suggest that the ruthenium(II) polypyridyl complexes can effectively enhance radiation-induced DNA damage, which is likely to benefit the imaging-guided cancer radio-chemotherapy.

Gallstone-Formation-Inspired Bimetallic Supra-nanostructures for Computed-Tomography-Image-Guided Radiation Therapy

Inspired by the gallstone formation mechanism, we report a fast one-pot synthesis of high-surface-area bimetallic hierarchical supra-nanostructures. As gallstones are generated from metal cholate complexes, cholate bile acid molecules with Au/Ag metal precursors formed stable nanocomplexes aggregated with metal Au ions and preformed ~2 nm silver halide nanoparticles before reduction. When a reducing agent was added, the metal cholate nanocomplexes quickly formed noble bimetallic hierarchical supra-nanostructures. The morphology of bimetallic supra-nanostructures could be tailored by changing the feeding ratio of each metal precursor. In situ synchrotron small-angle X-ray scattering measurement with a custom-designed reaction cell showed two-step growth and attachment behavior toward hierarchical supra-nanostructures from the gallstone-formation-inspired metal cholate nanocomplexes in a 60 s reaction. Additional wide-angle X-ray scattering, X-ray absorption near-edge structure, in situ Fourier transform infrared, and high-resolution scanning transmission electron microscopy investigations subsequently revealed the mechanism for the evolution of bimetallic hierarchical supra-nanostructures. The gallstone-formation-inspired synthesis mechanism can be universally applied to other metals, for example, Pt-Ag and Pd-Ag bimetallic nanostructures. Finally, the synthesized high-surface-area bimetallic supra-nanostructures demonstrated significantly enhanced X-ray computed tomography imaging contrast and radiosensitizing effect for a potential image-guided nanomedicine application. We believe that our synthetic method inspired by gallstone formation and understanding represents an important step toward the development of hierarchical nanoparticles for various applications.

Innovative Technologies Changing Cancer Treatment

Conventional therapies for cancer such as chemotherapy and radiotherapy remain a mainstay in treatment, but in many cases a targeted approach is lacking, and patients can be vulnerable to drug resistance. In recent years, novel concepts have been emerging to improve the traditional therapeutic options in cancers with poor survival outcomes. New therapeutic strategies involving areas like energy metabolism and extracellular vesicles along with advances in immunotherapy and nanotechnology are driving the next generation of cancer treatments. The development of fields such as theranostics in nanomedicine is also opening new doors for targeted drug delivery and nano-imaging. Here we discuss the use of innovative technologies presented at the Irish Association for Cancer Research (IACR) Annual Meeting, highlighting examples of where new approaches may lead to promising new treatment options for a range of cancer types.

Radiotherapy Enhancement with Electroporation in Human Intestinal Colon Cancer HT-29 Cells

Background: The efficiency of radiotherapy for tumors can be enhanced with different radiosensitizers. Previous studies have shown that electroporation (EP) can sensitize some cancer cell lines to ionizing radiation (IR). HT-29 is a radiation resistant colorectal cancer cell line, representative of a cancer type which is the second cause of cancer mortalities in developed countries. The present study aimed to evaluate radiosensitizing effects of EP on HT-29 cells in vitro exposed to 6 MV X-ray photon beams. Methods: HT-29 cells were exposed to a 6 MV X-ray photon beam as the control or to a combination of electroporation and irradiation. The response of cells was evaluated by colony formation assay and survival curves. Results: The survival fraction of the HT-29 cells was significantly decreased by electroporation prior to radiotherapy. A single electric pulse increased colorectal HT-29 cancer cell sensitivity to megavoltage radiation by a factor of 1.36. Conclusion: Our findings showed that EP before radiotherapy can significantly enhance tumor cell sensitivity. This combined treatment modality should be assessed for its applicability in clinic settings for employment against radioresistant cancers. However, to facilitate achieving this goal, many different tumors with a broad range of radiosensitivities should be evaluated.

Celecoxib-erlotinib combination treatment enhances radiosensitivity in A549 human lung cancer cell

BACKGROUND

Radiosensitivity by blocking the epidermal growth factor receptor and cyclooxygenase-2 pathways with erlotinib and celecoxib in A549 human lung cancer cell was investigated.

METHODS

MTT assays were used to detect the antitumor effects of erlotinib and celecoxib in A549 cells. Colony formation assays were used to evaluate the antitumor effects. Flow cytometry analysis was used to assess the cell cycle and cell apoptosis, and western blotting analysis was performed to evaluate the expression of AKT and phosphorylated AKT.

RESULTS

Either erlotinib or celecoxib inhibited the A549 cell proliferation in a dose-dependent manner. Combining Erlotinib or celecoxib with radiation can suppress the cell colony formation and the Dq, D0, SF2 of the combining erlotinib or celecoxib with radiation was lower than in the combinations either erlotinib or celecoxib with radiation (t= 6.62, P< 0.05). The SER of radiation with celecoxib or erlotinib and celecoxib and erlotinib were 1.299, 1.503 and 2.217, respectively. The Flow cytometry analysis results showed that either celecoxib or erlotinib could induce G0/G1 arrest, and reduction of S phase cell proportion, especially when combinations erlotinib-celecoxib with radiation. Either celecoxib or erlotinib could enhance radiation-induced apoptosis, especially significant when combinations erlotinib-celecoxib with radiation. Moreover, radiation can promote the expression of pAKT, and the pAKT was remarkably lowest in the combinations erlotinib-celecoxib with radiation group (t= 4.89, P< 0.05).

CONCLUSIONS

Blocking both EGFR- and COX-2-related pathways could enhance the antitumor effect of radiation. The underlying mechanisms including the enhancement of apoptosis and radiation-induced G0/G1 arrest, possibly via inhibiting the PI3K/AKT signaling pathway.

Correlation of hypoxia status with radiosensitizing effects of sodium glycididazole: A preclinical study

The correlation of pretreatment hypoxia status with the radiosensitization effect of sodium glycididazole (CMNa) was not previously defined. The purpose of the present study was to evaluate the tumor hypoxia status in various cancer xenografts and to investigate the correlation between tumor hypoxia status and radiosensitizing effects of CMNa based on the pharmacokinetic and pharmacodynamic parameters. Human esophageal cancer (EC109), head and neck cancer (FaDu) and lung cancer (A549) nude mice xenografts were used. The concentrations of CMNa and its metabolites in the tumors and normal tissues were determined by high-performance liquid chromatography following intravenous injection of 171.9, 57.3 or 19.1 mg/kg CMNa. The tumors were irradiated with 30 Gy in 6 fractions with CMNa administration prior to each irradiation. The tumor growth delay values were calculated for each treatment group and compared with groups treated with radiation alone. Tumor hypoxia status was verified by immunohistostaining of tissues for hypoxia inducible factor 1α (HIF-1α) staining, and the concentration of plasma osteopontin (OPN) was determined using ELISA. The correlation between OPN concentration and tumor growth delay was subsequently analyzed. It was observed that the drug concentration in the tumor was 1.6-2.8 times higher compared with adjacent muscle, particularly at high and medium doses. CMNa was able to sensitize tumors to irradiation, particularly for EC109 and FaDu xenografts at high dose (P<0.05). Furthermore, there was markedly increased expression of HIF-1α and plasma OPN levels in FaDu and EC109 xenografts compared with A549. Additionally, it was indicated that pretreatment hypoxia status might be correlated with the radiosensitizing effects of CMNa. The present data demonstrated that tumor hypoxia status might be correlated with the radiosensitizing effects of CMNa in different tumor models.

Recent Advances in Cancer Therapy Based on Dual Mode Gold Nanoparticles

Many tumor-targeted strategies have been used worldwide to limit the side effects and improve the effectiveness of therapies, such as chemotherapy, radiotherapy (RT), etc. Biophotonic therapy modalities comprise very promising alternative techniques for cancer treatment with minimal invasiveness and side-effects. These modalities use light e.g., laser irradiation in an extracorporeal or intravenous mode to activate photosensitizer agents with selectivity in the target tissue. Photothermal therapy (PTT) is a minimally invasive technique for cancer treatment which uses laser-activated photoabsorbers to convert photon energy into heat sufficient to induce cells destruction via apoptosis, necroptosis and/or necrosis. During the last decade, PTT has attracted an increased interest since the therapy can be combined with customized functionalized nanoparticles (NPs). Recent advances in nanotechnology have given rise to generation of various types of NPs, like gold NPs (AuNPs), designed to act both as radiosensitizers and photothermal sensitizing agents due to their unique optical and electrical properties i.e., functioning in dual mode. Functionalized AuNPS can be employed in combination with non-ionizing and ionizing radiation to significantly improve the efficacy of cancer treatment while at the same time sparing normal tissues. Here, we first provide an overview of the use of NPs for cancer therapy. Then we review many recent advances on the use of gold NPs in PTT, RT and PTT/RT based on different types of AuNPs, irradiation conditions and protocols. We refer to the interaction mechanisms of AuNPs with cancer cells via the effects of non-ionizing and ionizing radiations and we provide recent existing experimental data as a baseline for the design of optimized protocols in PTT, RT and PTT/RT combined treatment.

Enhanced Radiosensitization of Gold Nanospikes via Hyperthermia in Combined Cancer Radiation and Photothermal Therapy

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.