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Title: Prostate cancer stem-like cells proliferate slowly and resist etoposide-induced cytotoxicity via enhancing DNA damage response

Abstract

Despite the development of chemoresistance as a major concern in prostate cancer therapy, the underlying mechanisms remain elusive. In this report, we demonstrate that DU145-derived prostate cancer stem cells (PCSCs) progress slowly with more cells accumulating in the G1 phase in comparison to DU145 non-PCSCs. Consistent with the important role of the AKT pathway in promoting G1 progression, DU145 PCSCs were less sensitive to growth factor-induced activation of AKT in comparison to non-PCSCs. In response to etoposide (one of the most commonly used chemotherapeutic drugs), DU145 PCSCs survived significantly better than non-PCSCs. In addition to etoposide, PCSCs demonstrated increased resistance to docetaxel, a taxane drug that is commonly used to treat castration-resistant prostate cancer. Etoposide produced elevated levels of γH2AX and triggered a robust G2/M arrest along with a coordinated reduction of the G1 population in PCSCs compared to non-PCSCs, suggesting that elevated γH2AX plays a role in the resistance of PCSCs to etoposide-induced cytotoxicity. We have generated xenograft tumors from DU145 PCSCs and non-PCSCs. Consistent with the knowledge that PCSCs produce xenograft tumors with more advanced features, we were able to demonstrate that PCSC-derived xenograft tumors displayed higher levels of γH2AX and p-CHK1 compared to non-PCSC-produced xenograft tumors. Collectively,more » our research suggests that the elevation of DNA damage response contributes to PCSC-associated resistance to genotoxic reagents. - Highlights: • Increased survival in DU145 PCSCs following etoposide-induced cytotoxicity. • PCSCs exhibit increased sensitivity to etoposide-induced DDR. • Resistance to cytotoxicity may be due to slower proliferation in PCSCs. • Reduced kinetics to growth factor induced activation of AKT in PCSCs.« less

Authors:
 [1];  [2];  [3];  [1];  [2];  [3]
  1. Division of Nephrology, Department of Medicine, McMaster University, Juravinski Innovation Tower, Room T3310, St. Joseph's Hospital, 50 Charlton Ave East, Hamilton, Ontario, Canada L8S 4L8 (Canada)
  2. (Canada)
  3. (HCKR), St. Joseph's Hamilton Healthcare, Hamilton, Ontario, Canada L8N 4A6 (Canada)
Publication Date:
OSTI Identifier:
22416944
Resource Type:
Journal Article
Resource Relation:
Journal Name: Experimental Cell Research; Journal Volume: 328; Journal Issue: 1; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; CELL PROLIFERATION; COMPARATIVE EVALUATIONS; DNA DAMAGES; DRUGS; GROWTH FACTORS; NEOPLASMS; PROSTATE; SIGNALS; STEM CELLS; THERAPY; TOXICITY

Citation Formats

Yan, Judy, Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6, The Hamilton Centre for Kidney Research, Tang, Damu, E-mail: damut@mcmaster.ca, Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6, and The Hamilton Centre for Kidney Research. Prostate cancer stem-like cells proliferate slowly and resist etoposide-induced cytotoxicity via enhancing DNA damage response. United States: N. p., 2014. Web. doi:10.1016/J.YEXCR.2014.08.016.
Yan, Judy, Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6, The Hamilton Centre for Kidney Research, Tang, Damu, E-mail: damut@mcmaster.ca, Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6, & The Hamilton Centre for Kidney Research. Prostate cancer stem-like cells proliferate slowly and resist etoposide-induced cytotoxicity via enhancing DNA damage response. United States. doi:10.1016/J.YEXCR.2014.08.016.
Yan, Judy, Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6, The Hamilton Centre for Kidney Research, Tang, Damu, E-mail: damut@mcmaster.ca, Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6, and The Hamilton Centre for Kidney Research. Wed . "Prostate cancer stem-like cells proliferate slowly and resist etoposide-induced cytotoxicity via enhancing DNA damage response". United States. doi:10.1016/J.YEXCR.2014.08.016.
@article{osti_22416944,
title = {Prostate cancer stem-like cells proliferate slowly and resist etoposide-induced cytotoxicity via enhancing DNA damage response},
author = {Yan, Judy and Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6 and The Hamilton Centre for Kidney Research and Tang, Damu, E-mail: damut@mcmaster.ca and Father Sean O'Sullivan Research Institute, Hamilton, Ontario, Canada L8N 4A6 and The Hamilton Centre for Kidney Research},
abstractNote = {Despite the development of chemoresistance as a major concern in prostate cancer therapy, the underlying mechanisms remain elusive. In this report, we demonstrate that DU145-derived prostate cancer stem cells (PCSCs) progress slowly with more cells accumulating in the G1 phase in comparison to DU145 non-PCSCs. Consistent with the important role of the AKT pathway in promoting G1 progression, DU145 PCSCs were less sensitive to growth factor-induced activation of AKT in comparison to non-PCSCs. In response to etoposide (one of the most commonly used chemotherapeutic drugs), DU145 PCSCs survived significantly better than non-PCSCs. In addition to etoposide, PCSCs demonstrated increased resistance to docetaxel, a taxane drug that is commonly used to treat castration-resistant prostate cancer. Etoposide produced elevated levels of γH2AX and triggered a robust G2/M arrest along with a coordinated reduction of the G1 population in PCSCs compared to non-PCSCs, suggesting that elevated γH2AX plays a role in the resistance of PCSCs to etoposide-induced cytotoxicity. We have generated xenograft tumors from DU145 PCSCs and non-PCSCs. Consistent with the knowledge that PCSCs produce xenograft tumors with more advanced features, we were able to demonstrate that PCSC-derived xenograft tumors displayed higher levels of γH2AX and p-CHK1 compared to non-PCSC-produced xenograft tumors. Collectively, our research suggests that the elevation of DNA damage response contributes to PCSC-associated resistance to genotoxic reagents. - Highlights: • Increased survival in DU145 PCSCs following etoposide-induced cytotoxicity. • PCSCs exhibit increased sensitivity to etoposide-induced DDR. • Resistance to cytotoxicity may be due to slower proliferation in PCSCs. • Reduced kinetics to growth factor induced activation of AKT in PCSCs.},
doi = {10.1016/J.YEXCR.2014.08.016},
journal = {Experimental Cell Research},
number = 1,
volume = 328,
place = {United States},
year = {Wed Oct 15 00:00:00 EDT 2014},
month = {Wed Oct 15 00:00:00 EDT 2014}
}
  • We have previously shown that fluorodeoxyuridine (FdUrd) radiosensitizes HT29 human colon carcinoma cells. Since treatment with FdUrd arrests cells at the G{sub 1}/S-phase interface, a condition associated with increased radiation sensitivity in some cells, it seemed possible that redistribution of cells in the phases of the cell cycle might account for FdUrd-mediated radiosensitization. To begin to test this, HT29 cells were separated by centrifugal elutriation according to cell cycle phase and assessed for radiosensitivity, using a clonogenic assay, and radiation-induced DNA damage, using pulsed-field gel electrophoresis. We found that all of the elutriated fractions (which contained cells enriched in G{submore » 1}, G{sub 1}/early S, mid to late S or G{sub 2}/M phase) had the same radiation sensitivity and expressed a similar extent of radiation-induced DNA damage. To determine if the techniques used in this study could detect differences between the radiation sensitivity of cells in different phases of the cell cycle, analogous experiments were carried out using Chinese hamster ovary (CHO) cells. In contrast with the results of experiments with HT29 cells, but in agreement with previous studies, CHO cells separated under the same conditions as were used for HT29 cells showed a marked dependence on cell age of both clonogenic survival and radiation-induced DNA damage. Thus, within the limitations of the purity of separation obtained using elutriation, the radiation sensitivity of HT29 cells does not vary substantially as a function of cell cycle phase. Therefore, it seems unlikely that cell cycle redistribution alone explains the radiation sensitivity produced by exposure to FdUrd. 20 refs., 4 figs., 1 tab.« less
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