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A Cytoplasmic-Replicating RNA Virus Sensitizes Cancer Cells to DNA Modifying Agents

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Date Issued:
2019
Abstract/Description:
The Parainfluenza virus 5 (PIV5) mutant P/V-CPI- is restricted for spread in normal cells but not in cancer cells in vitro and is effective at reducing tumor burden in mouse model systems. Here we show that P/V-CPI- infection of human laryngeal cancer HEp-2 cells resulted in the majority of the cells dying, but unexpectedly, a population of cells emerged as P/V-CPI- persistently infected (PI) cells. P/V-CPI- PI cells had elevated levels of basal caspase activation, and viability was highly dependent on activity of cellular inhibitors of apoptosis, such as Survivin. In challenge experiments with external inducers of apoptosis, the PI cells were highly sensitive to cisplatin-induced DNA damage and cell death. This increased cisplatin sensitivity correlated with defects in the phosphorylation cascade controlling DNA damage signaling pathways, as well as translocation of damage-specific DNA binding protein 1 (DDB1) to the nucleus. Similar sensitivity to cisplatin was seen with cells during acute infection with P/V-CPI-, as well as acute infections with WT PIV5. Based on this finding, we tested the hypothesis that histone deacetylase (HDAC) inhibitors would also act with P/V-CPI- infection to enhance cancer cell killing. Using human lung and laryngeal cancer cell lines, 10 HDAC inhibitors were tested for their effect on viability of P/V-CPI- infected cells. HDAC inhibitors such as scriptaid enhanced caspase-3/7, -8 and -9 activity induced by P/V-CPI- and overall cell toxicity. Scriptaid treatment also enhanced the spread of P/V-CPI- through a population of cancer cells and suppressed interferon-beta induction through blocking phosphorylation and nuclear translocation of Interferon Regulatory Factor 3 (IRF-3). These results support a therapeutic approach of combining parainfluenza infection and chemotherapy, but also raise questions on the mechanism by which a cytoplasmic-replicating RNA virus can alter cellular DNA damage responses.
Title: A Cytoplasmic-Replicating RNA Virus Sensitizes Cancer Cells to DNA Modifying Agents.
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Name(s): Fox, Candace, Author
Parks, Griffith, Committee Chair
Copik, Alicja, Committee Member
Khaled, Annette, Committee Member
Zervos, Antonis, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2019
Publisher: University of Central Florida
Language(s): English
Abstract/Description: The Parainfluenza virus 5 (PIV5) mutant P/V-CPI- is restricted for spread in normal cells but not in cancer cells in vitro and is effective at reducing tumor burden in mouse model systems. Here we show that P/V-CPI- infection of human laryngeal cancer HEp-2 cells resulted in the majority of the cells dying, but unexpectedly, a population of cells emerged as P/V-CPI- persistently infected (PI) cells. P/V-CPI- PI cells had elevated levels of basal caspase activation, and viability was highly dependent on activity of cellular inhibitors of apoptosis, such as Survivin. In challenge experiments with external inducers of apoptosis, the PI cells were highly sensitive to cisplatin-induced DNA damage and cell death. This increased cisplatin sensitivity correlated with defects in the phosphorylation cascade controlling DNA damage signaling pathways, as well as translocation of damage-specific DNA binding protein 1 (DDB1) to the nucleus. Similar sensitivity to cisplatin was seen with cells during acute infection with P/V-CPI-, as well as acute infections with WT PIV5. Based on this finding, we tested the hypothesis that histone deacetylase (HDAC) inhibitors would also act with P/V-CPI- infection to enhance cancer cell killing. Using human lung and laryngeal cancer cell lines, 10 HDAC inhibitors were tested for their effect on viability of P/V-CPI- infected cells. HDAC inhibitors such as scriptaid enhanced caspase-3/7, -8 and -9 activity induced by P/V-CPI- and overall cell toxicity. Scriptaid treatment also enhanced the spread of P/V-CPI- through a population of cancer cells and suppressed interferon-beta induction through blocking phosphorylation and nuclear translocation of Interferon Regulatory Factor 3 (IRF-3). These results support a therapeutic approach of combining parainfluenza infection and chemotherapy, but also raise questions on the mechanism by which a cytoplasmic-replicating RNA virus can alter cellular DNA damage responses.
Identifier: CFE0007803 (IID), ucf:52355 (fedora)
Note(s): 2019-12-01
Ph.D.
Medicine,
Doctoral
This record was generated from author submitted information.
Subject(s): parainfluenza virus -- oncolytic virus -- DNA damage
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0007803
Restrictions on Access: campus 2024-12-15
Host Institution: UCF

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