Influence of bismuth oxide nanoparticles on bystander effects in MCF-7 and hFOB 1.19 cells under 10 MV photon beam irradiation

https://doi.org/10.1016/j.radphyschem.2020.109143Get rights and content

Highlights

  • The survivals of bystander cells are not affected by Bi2O3 NPs.

  • Bi2O3 NPs do not increased the ROS production in bystander cells.

  • Bi2O3 NPs do not influenced the bystander effects in MCF-7 and hFOB 1.19 cells.

Abstract

Background

Nanomaterials have been applied as radiosensitizer in an effort to improve the effectiveness of radiotherapy in killing cancer cells while simultaneously sparing the healthy normal tissue. Increase in radiotoxicity to the cancerous region might also influence the non-targeted cells through radiation-induced bystander effect (RIBE) mechanism. In this study, we implemented Bi2O3 NPs as radiosensitizer in combination with megavoltage radiotherapy and probe into the RIBE consequences in the non-targeted cells.

Aim

To investigate the effects of bismuth oxide nanoparticles (Bi2O3 NPs) on RIBE triggered in MCF-7 and hFOB 1.19 after irradiation with 10 MV clinical photon beam.

Materials and methods

The MCF-7 (human breast cancer) and hFOB 1.19 (human fetal osteoblast) cell lines were incubated with and without Bi2O3 NPs prior to irradiation. The treated cells were irradiated with radiation doses of 0 to 12 Gy using 10 MV photon beam in a single exposure. The irradiated-cell conditioned medium (ICCM) were collected from the targeted cells and transferred into the non-targeted cells. Reactive oxygen species (ROS), cell viability and colony forming assay was employed to evaluate the effect.

Results

The present study demonstrated that the MCF-7 and hFOB 1.19 bystander cells are able to maintain their cell viability for more than 80% after 48 h incubation with ICCM treated with Bi2O3 NPs at 2 Gy radiation dose. The percentage of cell survival fraction of hFOB 1.19 cells which received ICCM with Bi2O3 NPs decreased to 86.8%, in contrast to MCF-7 bystander cells which show an increment in their cells survival after treatment with Bi2O3 NPs. Our results show that the ROS level was increased in the bystander cells, but the addition of Bi2O3 NPs did not significantly increase the ROS level.

Conclusions

The application of nanoparticles for radiosensitization during radiotherapy must also considered the RIBE responses in the non-irradiated cells. These findings provide evidence that the use Bi2O3 NPs as radiosensitizer in radiotherapy is safe and do not significantly increase the RIBE responses in non-targeted cells.

Introduction

Radiotherapy is always recommended as the primary treatment of choice for cancer disease because of their superior clinical outcome compared to surgery, chemotherapy and the other alternative treatment. The advantage of radiotherapy over other treatment choices owing to better survival, local control, and profiles of quality of life or toxicity (Rosenblatt et al., 2018). However, irradiation of cancer cells may also affect the nearby normal cells in which could increase the risk of secondary cancer in the future. In an effort to improve the efficacy of cancer treatment, nanomaterials have been introduced to increase radiotoxicity to the cancerous region and minimize the biological effect on normal cells (Song et al., 2013). Extensive investigations have been carried out by researchers regarding enhancement of radiation toxicity on the targeted tumor cells through the application of radiosensitizer. The use of radiosensitizer such as gold nanoparticles (AuNPs), iron oxide nanoparticles (Fe3O4 NPs), platinum nanodendrites (PtNDs) and bismuth oxide nanoparticles (Bi2O3 NPs) have been reported as radiosensitizer that able to increase the effect of radiotherapy to cancerous area (Abidin et al., 2019; Khoshgard et al., 2017; Muhammad et al., 2018; Rahman et al., 2019, 2009; Rashid et al., 2018).

The existence of metallic nanoparticles within the cell produces a greater amount of secondary electrons from the radiation interactions. In consequences, increases in free radical numbers will contribute to deoxyribonucleic acid (DNA) molecules damages and cells death (Rahman et al., 2009). The biological effects of ionizing radiation were believed to be restricted to tissues within the treatment field due to direct targeting to the nucleus in which leading to DNA damage. Recently, attention in radiobiological studies has been widen to non-targeted effects of adjacent tissue surrounded the targeted area. The response of the non-irradiated cells to the radiation exposure is known as radiation-induced bystander effects (RIBE) (Marín et al., 2015). Bystander effects describe a situation where cells that have not been directly exposed to ionizing radiation behave as they though they have been exposed. As a result, the cells were killed or show chromosomal instability and other abnormalities (Mothersill and Seymour, 2004). RIBE in cells have been widely observed in radiobiology. Cells that are exposed to bystander signals can experience adverse effects including cell killing, the induction of micronuclei (MN), sister chromatid exchanges, mutations, genomic instability, changes in gene expression, decreases in cell proliferation and survival, changes in cell growth and cell death (Luo et al., 2018; Mothersill and Seymour, 2003; Shao et al., 2005). The RIBE may occurs through the transmitted signals from irradiated cells either by direct cell-to-cell contacts or by secretion of soluble factors into the medium (Rostami et al., 2016).

RIBE mainly expand the radiotoxicity effects to the non-targeted area. The application of radiosensitizer during the treatment rise up the issue if they could contribute to the RIBE in non-irradiated cells. Despite some promising investigations on RIBE, there are still gaps in understanding the mechanism and responses between the irradiated cells and adjacent healthy cells when radiosensitizer is applied during radiation treatment. Bystander effects may play an important role in radiotherapy. Understanding the bystander effects can improve radiobiological modelling of targeted tumor and minimizing the effect to healthy tissue (Zhang et al., 2016). The present in vitro study intended to examine the possibility of increment in RIBE as a result of Bi2O3 NPs application during radiotherapy for 10 MV photon beam. The RIBE responses between the normal and cancerous cells after the incubation with irradiated cell conditioned medium (ICCM) were also investigated.

Section snippets

Cell culture

MCF-7, human breast cancer cells line, and hFOB 1.19, human fetal osteoblast cell lines were used in the experiments. Cells were grown in tissue culture flask containing Dulbecco's modified Eagle's medium (DMEM) (Nacalai Tesque, Kyoto, Japan) which is supplemented with 10% fetal bovine serum and 1% antibiotics (10,000 units/mL penicillin and 10,000 μg/mL streptomycin) (Nacalai Tesque, Kyoto, Japan) in humidified atmosphere of 5% CO2 at 37°C. The stock cell cultures were maintained in

Cytotoxicity of Bi2O3

Human breast cancer cells MCF-7 and normal osteoblast hFOB 1.19 cell lines were treated with various concentrations of Bi2O3 (0–50 μMol/L) for 48 h. The effect of Bi2O3 NPs on cell viability was evaluated by PrestoBlue assay. Our results presented no signs of cytotoxicity in both cells when incubated with all concentration of Bi2O3 NPs for 48 h compared to untreated control cells (Fig. 1). Both treated cells were able to proliferate for more than 80% after 48 h exposures to Bi2O3 NPs at

Discussion

Several studies have been conducted to test the efficacy of Bi2O3 NPs as a radiosensitizer to enhance the effectiveness of radiation treatment (Abidin et al., 2019; Sisin et al., 2019; Stewart et al., 2016). However, its role in the bystander effect of radiation therapy has not yet been determined. To our knowledge, this is the first precedent to explore the consequence of Bi2O3 NPs in response to bystander effects of radiation.

The effect of nanomaterials is highly related to the

Conclusion

The present work provided the first in vitro study of the Bi2O3 NPs on the bystander effects in the non-targeted cells through medium transfer technique. In particular, to ensure the presence of radiosensitizer does not neutralized the therapeutic ratio, it is necessary to analyse the effect of Bi2O3 NPs on RIBE. Interestingly, our study demonstrates that the Bi2O3 NPs do not contribute and enhance the RIBE in both cancer and normal cells.

CRediT authorship contribution statement

Nur Hamizah Mohd Zainudin: Methodology, Investigation, Writing - original draft. Khairunisak Ab Razak: Resources, Investigation. Safri Zainal Abidin: Investigation. Reduan Abdullah: Investigation. Wan Nordiana Rahman: Conceptualization, Methodology, Writing - review & editing, Investigation, Supervision, Funding acquisition.

Declaration of competing interest

The authors declare that they have no known competing interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

This work was supported by Universiti Sains Malaysia Research University Grant (RUI:1001/PPSK/8012212).

References (38)

  • D. Fixler et al.

    Image and Flow Cytometric Analysis of Gold Nanoparticle Uptake by Macrophages 9721

    (2016)
  • K.K. Jella et al.

    Reactive oxygen species and nitric oxide signaling in bystander cells

    PLoS One

    (2018)
  • K. Khoshgard et al.

    Radiation dose rate affects the radiosensitization of MCF-7 and HeLa cell lines to X-rays induced by dextran-coated iron oxide nanoparticles

    Int. J. Radiat. Biol.

    (2017)
  • H. Klingberg et al.

    Uptake of gold nanoparticles in primary human endothelial cells

    Toxicol. Res. (Camb).

    (2015)
  • A. Kumar et al.

    A flow cytometric method to assess nanoparticle uptake in bacteria

    Cytom. Part A

    (2011)
  • G.G. Lara et al.

    Protection of normal cells from irradiation bystander effects by silica-flufenamic acid nanoparticles

    J. Mater. Sci. Mater. Med.

    (2018)
  • Y. Luo et al.

    Astragalus Polysaccharide Inhibits Ionizing Radiation-Induced Bystander Effects by Regulating MAPK/NF- k B Signaling Pathway in Bone Mesenchymal Stem Cells ( BMSCs )

    (2018)
  • F.M. Lyng et al.

    Production of a signal by irradiated cells which leads to a response in unirradiated cells characteristic of initiation of apoptosis

    Br. J. Canc.

    (2000)
  • E. Mladenov et al.

    Intercellular communication of DNA damage and oxidative status underpin bystander effects

    Int. J. Radiat. Biol.

    (2018)
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