- Title
- Identification of biomarkers and novel targets for prostate cancer from extracellular vesicles
- Creator
- Jankowski, Helen
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2019
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Prostate cancer is one of the most commonly diagnosed cancers in Australia with excellent long-term survival rates. The high survival is partly attributed to over- diagnosis, whereby men are being diagnosed with prostate cancer that actually have low-grade minimal tumour. This is likely due to the lack of specificity of the prostate specific antigen (PSA) test that is used for routine screening. Men with suspected indolent disease are then offered either active surveillance (frequent monitoring for signs of disease progression via PSA testing) or treatment with aggressive therapies that have high rates of severe side effects. It is therefore imperative that improvements are made to the screening and diagnosis of prostate cancer to ensure only those men needing aggressive treatment for survival are offered this course of action and that no man that needs immediate treatment is provided the active surveillance approach. This thesis is focused on finding a panel of biomarkers from extracellular vesicles (EVs) to distinguish indolent prostate cancer from more aggressive forms and to do this in a non- invasive manner. Thereby improving outcomes, quality of life and reducing the high cost to the health care system. EVs were collected from the media of four groups of prostate cancer cell lines: non- tumourigenic EVs (normal), prostate cancer derived EVs (prostate cancer), prostate cancer metastatic site EVs (metastasis), and benign prostatic hyperplasia (BPH), and the abundance of their RNA cargo was investigated using human transcriptome microarrays. Eleven transcripts were identified and tested by qPCR for validation. A statistically significant decrease in the abundance of VTRNA1-2, and increase in abundance of SCARNA4, and SNORA54 could differentiate metastasis from normal EVs. A decrease in abundance of VTRNA1-1, VTRNA1-2, and VTRNA1-3, was able to distinguish metastasis from prostate cancer EVs. VTRNA1-1 has been linked to drug resistance and apoptosis protection. The tetraspanins CD9 and CD151 are potential biomarkers in prostate cancer. With decreased CD9 and increased CD151 indicating a poor prognosis for prostate cancer patients. By altering the expression to mimic this poor prognosis in prostate cells, an EV cargo biomarker was investigated. SNORA3B and SNORA75 were identified to be incorporated with tetraspanin expression and may provide increased capacity to predict patient outcome from a non-invasive tissue source. Further, increased SNORA3B EV abundance seems to have a link with a low cellular CD9 expression. As EVs contain fragmented RNA transcripts, small RNA-Seq was performed to investigate additional potential biomarkers from the four groups of prostate cell line EVs. miR-205-5p, miR-31-5p, and miR-155 were found to have very low abundance in metastasis samples compared to the other groups, which was confirmed by qPCR. miR-205-5p, miR-31-5p have been shown previously to indicate drug resistance. miR-31-5p is also involved in osteoblastic and osteolytic activity, and androgen receptor (AR) status. Fragments of the three vault RNAs identified as biomarkers of metastasis, VTRNA1-1, VTRNA1-2 and VTRNA1-3, have been shown to have cancer related functions, for example in drug resistance and tumour suppressor or promoter capacity, therefore abundance of these transcript fragments was specifically investigated. In all three VTRNA genes two highly abundant fragments were observed which mapped to the 5’ and 3’ ends of the gene structure, and the fragment with the lowest abundance mapped to the stem-loop structures on all three VTRNAs. A fragment in the 5’ end of VTRNA1-1 has been shown to play a role in drug resistance. In conclusion, the differentially expressed EV RNAs SCARNA4, SNORA54, VTRNA1-1, VTRNA1-2, VTRNA1-3, miR-205-5p, miR-31-5p, and miR-155 may serve as potential biomarkers for the prognosis and diagnosis of metastatic disease in prostate cancer. Further, due to their previously identified functions, VTRNA1-1, miR-205-5p and miR-31-5p may have the ability to determine drug resistance in patients. miR-31-5p may also provide a way to monitor castrate resistant prostate cancer (CRPC) transition as well as a bone metastatic biomarker of osteoblastic and osteolytic activity.
- Subject
- prostate cancer; biomarker; extracellular vesicles
- Identifier
- http://hdl.handle.net/1959.13/1405557
- Identifier
- uon:35516
- Rights
- Copyright 2019 Helen Jankowski, This thesis is currently under embargo and will be available 9 October 2021
- Language
- eng
- Full Text
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