Pt(II) chemotherapies, including cisplatin and oxaliplatin, have been used in cancer treatment since the 1970s, however, a full understanding of the mechanism by which these drugs function is still lacking. While the interaction between Pt(II) drugs and DNA has been extensively studied and subsequently indicted in the cellular response to Pt(II) drugs, recent data indicates non-DNA targets play important roles as well. To gain insight into the non-DNA damage-based effects induced by these drugs, MDA-MB-468 cells were treated at therapeutic concentrations of cisplatin between 30 minutes and 24 hours. Not only does this data provide insight into the complex time-dependent nature of the cellular response to cisplatin, but novel responses were also observed.
First, I describe how the expression of numerous snoRNAs decreases as early as 30 minutes post-treatment with either cisplatin or oxaliplatin, and differential expression analysis indicates this occurs before activation of the DNA damage response. Since snoRNAs are necessary components in ribosome processing, we sought to determine the role snoRNAs play in the cellular response to Pt(II) drugs. A subgroup of our identified snoRNAs direct modification of helix 69 on the 28S ribosome. Quantification of methylation of helix 69 and other locations suggests cisplatin induced changes in snoRNA expression leads to dysregulation of rRNA modification, likely altering ribosome activity. I also observe varied activation of different types of DNA damage and cell cycle arrest between 3 and 12 hours of cisplatin treatment while early expression changes show downregulation of mitochondrial genes. We also identify a number of lncRNAs previously associated with TNBC that are downregulated after cisplatin treatment. This study establishes a gene expression profile induced by cisplatin treatment of triple-negative breast cancer that demonstrates the complex interplay of multiple means of stress induction. Lastly, we establish a method for analyzing direct DNA binding targets of platinum(II) chemotherapeutics. This pilot study confirms high accumulation of platinum(II) compounds on guanine-rich DNA and suggests DNA binding of significant genes leads to changes in their RNA expression. / 10000-01-01
| Identifer | oai:union.ndltd.org:uoregon.edu/oai:scholarsbank.uoregon.edu:1794/23758 |
| Date | 06 September 2018 |
| Creators | Reister, Emily |
| Contributors | Hawley, Diane |
| Publisher | University of Oregon |
| Source Sets | University of Oregon |
| Language | en_US |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Rights | All Rights Reserved. |
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