Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Doctor of Philosophy (Medical Science)

Document Type

Doctoral Dissertation




Toxicology and Cancer Biology

First Advisor

Dr. Luksana Chaiswing

Second Advisor

Dr. Daret St. Clair


Radiation treatment (RT) is one of the most commonly administered treatments for prostate cancer (PCa) patients, yet the recurrence of tumors after RT remains one of the significant challenges in the eradication of PCa. In addition to induction of DNA damage, ROS production, and cell death, we found that RT promotes Extracellular vesicle (EV) production in PCa cells, at least in part, through H2O2 production (Miller CE et al., Antioxidants 2022, PMID 36358489). Since we observed EV production upon RT, EVs and their contents could play a role(s) in cancer survival after RT. By using flow cytometry coupled with Mitotracker Green for particle counting, we found that ~50% of RT-derived EVs from PCa cells carried mitochondrial components (EVs-Mito). These RT-derived EVs contained an increased level of mitochondrial antioxidants, such as Peroxiredoxin 3 (Prx3), Glutathione peroxidase 4 (Gpx4), and Manganese Superoxide Dismutase (MnSOD), as well as mitochondrial transcription factor, TFAM. Significantly, this phenomenon is specific for both androgen independent and androgen dependent PCa cells, since we did not observe a significant increase in EV number and EVs-Mito released from normal prostate epithelial cell lines PZ and PrEC post RT. To test that the selective release of RT-derived EVs-Mito could act as mediator in PCa survival post RT, we treated PC3 cells with sorted EVs-Mito and performed a colony survival assay subsequent to RT. Our data shows that the uptake of EVs-Mito post RT significantly promotes survival, increases levels of TFAM protein, and decreases ROS production in PC3 cells. Given that TFAM is essential for cell survival and significant levels of TFAM were found in RT-derived EVs-Mito, we inhibited TFAM levels in PCa cells (PCa_TFAMKD) and further found that the knockdown of TFAM sensitized PCa to RT, both in vitro and in vivo. Significantly, PCa_TFAMKD cells and tumors released lower numbers of RT-derived EVs-Mito and a lower amount of TFAM into the EVs, compared to the parental PCa cells and WT prostate tumors. Moreover, uptake of RT-derived EVs-Mito by PCa_TFAMKD cells increases levels of TFAM protein and promotes cell survival post RT. Our data suggests that RT-derived EVs-Mito are mediators of PCa survival and regrowth post RT. Our data also suggests that TFAM plays a key role in this process. In identifying this mechanism, we hope to help improve the efficacy of RT by targeting TFAM during RT to mitigate cancer recurrence in PCa patients.

Digital Object Identifier (DOI)

Funding Information

This study was supported by:

  • DTCB Research Fellowship 2020, 2021
  • Dr. Matt Devalaraja Graduate Student Career Support Award 2022, 2023
  • College of Medicine Student Travel Award 2023
  • Markey Cancer Center Student Career Support Award 2022
  • Markey Women Strong Award to Dr. Luksana Chaiswing, 2021-2024
  • NIH 1R01CA251663-01A1 to Dr. Luksana Chaiswing, 2020-2024

Available for download on Sunday, March 01, 2026