The chicken model of ovarian cancer: A novel TP53 mRNA variant found in healthy and cancerous tissue
Open Access
- Author:
- Montani, Aaron William
- Graduate Program:
- Physiology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- October 03, 2014
- Committee Members:
- Ramesh Ramachandran, Thesis Advisor/Co-Advisor
Joy Lee Pate, Thesis Advisor/Co-Advisor
Alan Leslie Johnson, Thesis Advisor/Co-Advisor - Keywords:
- ovarian cancer
chicken
gallus
TP53
P53
mRNA
variant
splicing
deletion - Abstract:
- Ovarian cancer (OC) is a disease encompassing the highest death rate of any cancer of the female reproductive tract. It is the fifth leading cause of cancer related death among women, after lung, breast, colon, and pancreatic cancer. Ovarian tumors are difficult to diagnose early due to their location deep within the pelvis and a lack of sensitive, specific diagnostic biochemical tests. Currently, there are no established animal models of spontaneously occurring OC. The laying hen model of ovarian carcinoma is gaining acceptance as a model of OC, due to spontaneous generation of ovarian tumors as well as the similarity to human OC progression. Gene mutations are known to be concurrent with human cancers, including OC. The TP53 gene is a tumor suppressing gene known to be mutated in over 60% of human cancers. Mutations in TP53 have been associated with OC in humans. Point mutations of the TP53 mRNA transcript have been detected in chicken OC. The objective of this study was to compare chicken TP53 mRNA transcript in chicken OC with that of age-matched and young controls, ascites-derived chicken ovarian cancer cell lines, liver, and adipose tissue. Total RNA was extracted from ovarian tissue, ascites-derived ovarian cancer cell lines, liver and adipose tissue. Total RNA was reverse-transcribed to cDNA and the TP53 gene amplified by polymerase chain reaction (PCR) using gene-specific primers. The resultant PCR products were gel-purified and sequenced. Point mutations were discovered within the mRNA transcript. Interestingly, a deletion of 216 nucleotides spanning part of the transactivation domain and the entire proline-rich region was detected in all ovarian tumor, as well as age-matched and young healthy controls, ascites-derived chicken ovarian cancer cell lines, liver and adipose tissue. The deletion may be the result of yet unknown alternative splicing events during the biosynthesis of TP53 mRNA. The deletions characterized in this study share similarity to isoforms of TP53 overexpressed in human cancer. In summary, alternative splicing events may produce a shorter form of the TP53 mRNA transcript that may contribute to the development of OC in chickens.