Date of Award

Fall 12-16-2016

Level of Access

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Sciences

Advisor

Robert Gundersen

Second Committee Member

Bernard Kwabi-Addo

Third Committee Member

Dorothy Klimis-Zacas

Additional Committee Members

Stephen Pelsue

Shallee Page

Abstract

In the United States, prostate cancer was expected to account for 220,800 of the estimated 848,200 new cases of the four major cancers in men for the year 2015. Mortality, morbidity and cost of prostate cancer management continue to be a concern.

Early detection of prostate cancer is essential in the successful management of the disease. Part of the diverse efforts being made towards the development of more specific and sensitive methods for the early detection of prostate cancer includes the identification of novel targets. The promoter region of Orthopedia homeobox (OTP) has been demonstrated to be hypermethylated in a panel of human prostate cancer cell lines but there is no information on the functional relevance of this gene in the normal human prostate.

Thus, the main objective of this study was to determine the role of orthopedia homeobox in prostate epithelial cell cycle with the aim of contributing to the characterization of the functional relevance of the gene in normal prostate tissue and also ascertaining the pathological relevance of orthopedia homeobox promoter hypermethylation in prostate cancer.

An RT2 Profiler PCR Array was used to investigate the effect of OTP overexpression in RWPE-1 cells, whilst RT-PCR was used to determine the outcome of OTP promoter hypermethylation and demethylation agents on the expression of the gene. RT-PCR was also used to validate specific differentially expressed genes from the RT2 Profiler PCR Arrays.

Results from the study show that OTP promoter hypermethylation leads to a greater than two fold reduction in corresponding gene expression. It was also found that treating LNCaP cells with a demethylation agent resulted in increased OTP expression. Further results demonstrated a differential expression of BCCIP, MAD2L1, CCNG1, CCNG2, CDK1, AURKB, MAD2L2, CDK5R1, WEE1, CDK6, GADD45A, CCND1 and CCND2 in RWPE-1 cells following OTP overexpression. Additionally, OTP overexpression in LNCaP and PC3 cells led to a reduction in their proliferation.

OTP may thus be functionally relevant in prostate epithelial cells by participating in tumor suppressor networks and other differentiation pathways.

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