Therapeutic Efficacy of Carbon Ion Irradiation Enhanced by 11-MUA-Capped Gold Nanoparticles: An in vitro and in vivo Study

Int J Nanomedicine. 2021 Jul 6:16:4661-4674. doi: 10.2147/IJN.S313678. eCollection 2021.

Abstract

Purpose: Gold nanoparticles (AuNPs) are widely studied as radiosensitizers, but their radiosensitization in carbon ion radiotherapy is unsatisfactory. There is a lack of in vivo data on the radiosensitization of AuNPs under carbon ion irradiation. This study focused on the radiosensitization effect of AuNPs in the mouse melanoma cell line B16-F10 in vitro and in vivo.

Materials and methods: 11-mercaptoundecanoic acid (11-MUA)-coated gold (Au) nanoparticles (mAuNPs) formulations were prepared and characterized. To verify the radiosensitization effect of mAuNPs, hydroxyl radicals were generated in aqueous solution, and the detection of intracellular reactive oxygen species (ROS) and clone survival were carried out in vitro. The tumor growth rate (TGR) and survival of mice were analyzed to verify the radiosensitization effect of mAuNPs in vivo. The apoptosis of tumor cells was detected, and the expression of key proteins in the apoptosis pathway was verified by immunohistochemistry.

Results: The intracellular ROS level in B16-F10 cells was enhanced by mAuNPs under carbon ion irradiation. The sensitization rate of mAuNPs was 1.22 with a 10% cell survival rate. Compared with irradiation alone, the inhibitory effect of mAuNPs combined with carbon ion irradiation on tumor growth was 1.94-fold higher, the survival time of mice was prolonged by 1.75-fold, and the number of apoptotic cells was increased by 1.43-fold. The ratio of key proteins Bax and Bcl2 in the apoptosis pathway was up-regulated, and the expression of caspase-3, a key executor of the apoptosis pathway, was up-regulated.

Conclusion: In in vivo and in vitro experiments, mAuNPs showed radiosensitivity to carbon ion irradiation. The sensitization effect of mAuNPs on mice tumor may be achieved by activating the mitochondrial apoptosis pathway and increasing tumor tissue apoptosis. To our best knowledge, the present study is the first in vivo evidence for radiosensitization of mAuNPs in tumor-bearing mice exposed to carbon ion irradiation.

Keywords: apoptosis; carbon ion irradiation; gold nanoparticles; radiosentization; tumor-bearing mice.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Clone Cells
  • Fatty Acids / chemistry*
  • Female
  • Gold / chemistry*
  • Heavy Ion Radiotherapy*
  • Humans
  • Image Processing, Computer-Assisted
  • Melanoma, Experimental / pathology
  • Melanoma, Experimental / radiotherapy
  • Metal Nanoparticles / chemistry*
  • Metal Nanoparticles / ultrastructure
  • Mice
  • Mice, Inbred C57BL
  • Reactive Oxygen Species / metabolism
  • Sulfhydryl Compounds / chemistry*
  • Survival Analysis
  • Treatment Outcome
  • Tumor Burden

Substances

  • 11-mercaptoundecanoic acid
  • Fatty Acids
  • Reactive Oxygen Species
  • Sulfhydryl Compounds
  • Gold

Grants and funding

This work is jointly supported by the Key Deployment Project of Chinese Academy of Sciences (Grant No. KFZD-SW-222), the National Natural Science Foundation of China (Grant No. 11875299), the Key R&D Program of Gansu Provincial Department of Science and Technology (Grant No. 20YF3FA028), Gansu Health Industry Scientific Research Project (Grant No. GSWSKY-2019-79), In-hospital Funded Project of Lanzhou University First Hospital (Grant No. ldyyyn 2018-21), the Science and Technology Project of Chengguan District, Lanzhou City (Grant No. 2020-2-2-6).