1. Academic Validation
  2. Ultrasound-triggered microbubble destruction enhances the radiosensitivity of glioblastoma by inhibiting PGRMC1-mediated autophagy in vitro and in vivo

Ultrasound-triggered microbubble destruction enhances the radiosensitivity of glioblastoma by inhibiting PGRMC1-mediated autophagy in vitro and in vivo

  • Mil Med Res. 2022 Feb 14;9(1):9. doi: 10.1186/s40779-022-00369-0.
Ying He 1 Xun-Hu Dong 2 3 Qiong Zhu 1 Ya-Li Xu 1 Ming-Liang Chen 4 5 6 Zheng Liu 7
Affiliations

Affiliations

  • 1 Department of Ultrasound, Xinqiao Hospital, Third Military Medical University (Army Medical University), Chongqing, 400037, China.
  • 2 Department of Chemical Defense Medicine, School of Military Preventive Medicine, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
  • 3 Institute of Toxicology, School of Military Preventive Medicine, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
  • 4 Department of Chemical Defense Medicine, School of Military Preventive Medicine, Third Military Medical University (Army Medical University), Chongqing, 400038, China. chenmingliang1987@163.com.
  • 5 Institute of Toxicology, School of Military Preventive Medicine, Third Military Medical University (Army Medical University), Chongqing, 400038, China. chenmingliang1987@163.com.
  • 6 Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China. chenmingliang1987@163.com.
  • 7 Department of Ultrasound, Xinqiao Hospital, Third Military Medical University (Army Medical University), Chongqing, 400037, China. liuzhengs@163.com.
Abstract

Background: Ultrasound-triggered microbubble destruction (UTMD) is a widely used noninvasive technology in both military and civilian medicine, which could enhance radiosensitivity of various tumors. However, little information is available regarding the effects of UTMD on radiotherapy for glioblastoma or the underlying mechanism. This study aimed to delineate the effect of UTMD on the radiosensitivity of glioblastoma and the potential involvement of Autophagy.

Methods: GL261, U251 cells and orthotopic glioblastoma-bearing mice were treated with ionizing radiation (IR) or IR plus UTMD. Autophagy was observed by confocal microscopy and transmission electron microscopy. Western blotting and immunofluorescence analysis were used to detect Progesterone Receptor membrane component 1 (PGRMC1), light chain 3 beta 2 (LC3B2) and sequestosome 1 (SQSTM1/p62) levels. Lentiviral vectors or siRNAs transfection, and fluorescent probes staining were used to explore the underlying mechanism.

Results: UTMD enhanced the radiosensitivity of glioblastoma in vitro and in vivo (P < 0.01). UTMD inhibited autophagic flux by disrupting autophagosome-lysosome fusion without impairing lysosomal function or autophagosome synthesis in IR-treated glioblastoma cells. Suppression of Autophagy by 3-methyladenine, bafilomycin A1 or ATG5 siRNA had no significant effect on UTMD-induced radiosensitization in glioblastoma cells (P < 0.05). Similar results were found when Autophagy was induced by rapamycin or ATG5 overexpression (P > 0.05). Furthermore, UTMD inhibited PGRMC1 expression and binding with LC3B2 in IR-exposed glioblastoma cells (P < 0.01). PGRMC1 inhibitor AG-205 or PGRMC1 siRNA pretreatment enhanced UTMD-induced LC3B2 and p62 accumulation in IR-exposed glioblastoma cells, thereby promoting UTMD-mediated radiosensitization (P < 0.05). Moreover, PGRMC1 overexpression abolished UTMD-caused blockade of autophagic degradation, subsequently inhibiting UTMD-induced radiosensitization of glioblastoma cells. Finally, compared with IR plus UTMD group, PGRMC1 overexpression significantly increased tumor size [(3.8 ± 1.1) mm2 vs. (8.0 ± 1.9) mm2, P < 0.05] and decreased survival time [(67.2 ± 2.6) d vs. (40.0 ± 1.2) d, P = 0.0026] in glioblastoma-bearing mice.

Conclusion: UTMD enhanced the radiosensitivity of glioblastoma partially by disrupting PGRMC1-mediated Autophagy.

Keywords

Autophagy; Glioblastoma; Progesterone receptor membrane component 1; Radiosensitization; Ultrasound-triggered microbubble destruction.

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