Zinc nanoparticles coated with doxorubicin-conjugated alginate as a radiation sensitizer in triple-negative breast cancer cells

The main treatment modalities for breast cancer include surgery, chemotherapy, and radiotherapy, and each treatment will bring different side effects. Design and synthesizing a novel nanostructure for chemo-radiotherapy has been proposed as an effective method in consideration to enhance the drug efficiency as well as improve the effect of radiotherapy. This study aimed to synthesize zinc nanoparticles (ZnNPs) coated with alginate conjugated with Doxorubicin (Dox) drug and investigate its effects along with X-irradiation on MDA-MB-231 triple-negative breast cancer cell line. ZnNPs coated with alginate were synthesized and conjugated to Dox by covalent bonding and characterized using various physicochemical tests. A hemolysis test was used to assess blood biocompatibility. The radiosensitization properties and anti-cancer effects of the synthesized nanostructures were tested by cell uptake, cell viability, apoptosis, cell cycle, and scratch assays with and without radiation exposure. The physicochemical characterization results showed that the synthesis of nanostructures was successfully carried out. The obtained results from the cell uptake assay showed the effective absorption of nanostructures by the cells. The Zn@Alg-Dox NPs significantly reduced cell growth, increased apoptosis, inhibited cell migration, and led to the arrest of different cell cycle phases in both conditions with and without X-ray exposure. Coating ZnNPs with alginate and Doxorubicin conjugation leads to an increase the radiation sensitivity in radiotherapy as well as therapeutic efficiency. Therefore, Zn@Alg-Dox NPs can be used as radiosensitizing nanomedicine for in vivo studies in the future.

Enhanced radiotherapy efficacy of breast cancer multi cellular tumor spheroids through in-situ fabricated chitosan-zinc oxide bio-nanocomposites as radio-sensitizing agents

Overwhelming evidence has shown that three-dimensional multicellular tumor spheroids (MCTSs) as a mimic of in-vivo tumor can accurately exhibit cellular responses to treatments. So, we compared the capability of pure zinc oxide nanoparticles (ZnO-NPs) and chitosan-ZnO bio-nanocomposites (CS-ZnO BNCs) for enhancing the radiosensitization of MDA-MB-231 breast cancer cells (BCCs) in the 3D-MCTSs model. ZnO-NPs and CS-ZnO BNCs were synthesized by a facile co-precipitation method. FE-SEM images revealed that the uniform spherical ZnO-NPs with an average diameter of 35 nm were successfully dispersed on chitosan. MDA-MB-231 MCTSs which were formed in a non-adherent culture plate, possessed functional features of in-vivo tumor. The priority of such culture method to conventionally used 2D monolayer (or parental) cell culture is the mimicking of tumor microenvironment. The toxicity of CS-ZnO BNCs and ZnO-NPs against the MDA-M-231 BCCs was evaluated using MTT-colorimetric assay, which demonstrated superior biocompatibility of CS-ZnO BNCs compared to pure ZnO-NPs (even at high concentration of 100 μg/mL). Survival fraction analysis of cells under clinical X-ray irradiation (6 MV) showed that MCTSs had a higher radioresistance compared to parental cells. Besides, the clonogenic potential of irradiated MCTSs was significantly decreased by the addition of CS-ZnO BNCs similar to that of monolayer cells. The sensitivity enhancement ratios (SER) for MCTSs and monolayer cells were calculated 1.5 and 1.63, respectively. Further, tracking of radiobiological properties and apoptosis induction of MCTSs showed that CS-ZnO BNCs not only could lead to the creation of higher radiation-induced complex DNA break and apoptosis death in MCTSs, but also weakened DNA repair mechanisms. It was found that non-toxic concentration of CS-ZnO BNCs has promising potential to enhance radiosensitivity of resistant-MCTSs as a superior in-vitro tumor model. So, CS-ZnO BNCs can be a prominent candidate for overcoming the resistance of BCCs to radiotherapy.

Promoting reactive oxygen species generation: a key strategy in nanosensitizer-mediated radiotherapy

The radiotherapy enhancement effect of numerous nanosensitizers is based on the excessive production of reactive oxygen species (ROS), and only a few systematic reviews have focused on the key strategy in nanosensitizer-mediated radiotherapy. To clarify the mechanism underlying this effect, it is necessary to understand the role of ROS in radiosensitization before clinical application. Thus, the source of ROS and their principle of tumor inhibition are first introduced. Then, nanomaterial-mediated ROS generation in radiotherapy is reviewed. The double-edged sword effect of ROS and the potential dangers they may pose to cancer patients are subsequently addressed. Finally, future perspectives regarding ROS-regulated nanosensitizer applications and development are discussed.

Au nanoshell-coated superparamagnetic Fe3O4–silica composite nanoparticles with surface-modification of an activatable cell-penetrating peptide for tumor-targeted multimode bioimaging and photothermal therapy

The superparamagnetic Fe₃O₄–silica composite nanoparticles coated with Au nanoshells were prepared and subsequently surface-modified with PEG conjugated ACPP for realizing the tumor site-specific multimode bioimaging and photothermal therapy.