MIRNAS AS BIOMARKERS FOR PROSTATE CANCER PROGRESSION

• Main Author: Clark, Gene C
• Format: Others
• Published: VCU Scholars Compass 2015
• Subjects: Diagnosis
• Online Access: http://scholarscompass.vcu.edu/etd/3954; http://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=4985&context=etd

Prostate cancer is one of the most challenging global medical issues today. In 2011, prostate cancer was the most diagnosed malignancy in the United States, making up 29% of new cancer cases. In that year it was the second leading cause of cancer related deaths among men in the USA and the second most common cause of cancer related death overall from the EU. The prostate remains, however, an under studied organ, making insights into the anatomy and biology of prostate cancer difficult to achieve. After 30 years, PSA screening of men of the appropriate age is still the first step in prostate cancer diagnosis, usually followed by a manual prostate exam which may lead to a transrectal biopsy. This study makes use of Next Generation Sequencing to successfully identify a superior miRNA based urinary assay for the detection of prostate cancer. A receiver operating curve AUC of 0.90 was achieved for patients vs. non-patients using an additive risk model defined by empirically derived critical threshold values of eight urinary miRNAs identified with this method. This is superior to the PSA blood test’s AUC of 0.66 which illustrates that a miRNA profile such as this has the potential to surpass protein biomarkers such as PSA in terms of specificity and sensitivity. It was also demonstrated that a geometric mean of three urinary miRNAs were useful for endogenous normalization. One significant risk factor for prostate cancer is being African American. Again using Next Generation Sequencing technology, we have established a miRNA expression profile for the stages of a prostate cancer cell line progression model derived from the normal prostate epithelium of an African American man. Normal prostate epithelium was immortalized only with SV40 large T antigen (P69) and passaged three times in nude mice, producing the highly aggressive and metastatic M12 cell line. The M2182 cell line is an intermediate between the P69s and M12s having only been passaged twice and not yet having acquired metastatic potential. The F6 cell line was derived by reintroducing a copy of chromosome 19 missing from the M12 cell line via microcell mediated chromosome transfer. These profiles show a large downregulation of miRNAs early in tumorigenesis (from P69 toM2182) affecting the DLK1-DIO3 megacluster and the miR-200 family. The later acquisition of metastatic potential (from M2182 to M12) is concomitant with the upregulation of specific miRNAs including the HOX gene miRNAs miR-10a and miR-196 and miR-9. Thus, the analysis of this progression model has uncovered relevant miRs and genes the dysregulation of which contribute to prostate tumorigenesis.