Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Sedik, S.
In situ analysis of liquid biopsy in prostate cancer.
[ Diplomarbeit/Master Thesis (UNI) ] Universität Graz; 2023.
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- El-Heliebi Amin
- Altmetrics:
- Abstract:
- Prostate cancer (PC) is the second most common malignancy in men. Novel anti-hormonal drugs targeting the androgen receptor (AR) signaling pathways are used for treatment. Although the majority initially respond to therapy, most patients eventually acquire drug resistance due to various AR splice variants (e.g., AR-V7). In patients with AR-V7 positive circulating tumor cells (CTCs), the treatment with chemotherapy is more effective than with the anti-hormonal drugs. For treatment decision a reliable, non-invasive detection of the biomarker AR-V7 would be of high clinical relevance. An in situ padlock probe (PLP) technology has been established by El-Heliebi et al. (2018) allowing the detection and quantification of AR-V7 and other PC related transcripts. This technology can directly be performed on CTCs captured by a medical wire, the GILUPI CellCollector (detector CANCER01; DC01), from PC patients. In this thesis, a post-imaging process was established using the Olympus cellSens Dimension software. The seeding protocol was optimized by using 1x Hanks Balanced Salt Solution washing buffer, instead of 10% fetal bovine serum as it inhibited the assay. Further, the in situ PLP assay was validated in 3 independent experiments. The focus was on the detection of AR- full length (AR-FL) and AR-V7. Additionally, another clinically relevant biomarker in PC the prostate specific membrane antigen (PSMA) and a negative selection marker for blood cells (peripheral blood mononuclear cells; PBMCs) were analyzed. The experiments confirmed that the in situ PLP assay enables the detection and quantification of AR-V7, AR-FL, PSMA in a PC cell line and PBMC markers in blood cells and can be applied on CellCollectors. Finally, 5 tissue samples and the CTC status of 11 DC01 samples from PC patients with primary and metastatic tumor were evaluated. In situ analysis revealed that 100% (5/5) of the tissue samples and 51% (6/11) of the DC01 samples had detectable AR-V7, AR-FL, PSMA and/or PBMC transcripts. In future, this in situ PLP based liquid biopsy assay might be used to detect the biomarker AR-V7 in CTCs isolated from PC patients and thus help fill the gap between diagnosis and therapy treatment.