Date of Award

Spring 5-10-2014

Degree Type

Thesis

Department

Chemistry and Biochemistry

Director of Thesis

Maria Marjorette Peña

First Reader

Hexin Chen

Abstract

Metastasis, frequently from the colon to the liver, is the major cause of death with colorectal cancer, reducing the five-year survival to less than 6%. Metastasis occurs due to productive collaborations between tumor cells and host-derived cells in the tumor microenvironment, where a pre-metastatic niche is created to prime for cancer cell invasion into the target organ. In a highly metastatic colorectal cancer cell line implanted into the cecum of Balb/c mice, microarray analysis showed lipocalin 2 (Lcn2) is one of the most highly expressed proteins in the liver of tumor-bearing mice prior to metastasis.

When RT-PCR was performed, greater levels of Lcn2 mRNA were found in highly metastatic cells in contrast to less metastatic cells that had been stably transfected. Intracellular protein presence through western blot analysis and examination of media secretion by ELISA illustrated increased levels of Lcn2 secretion with the same cell lines. These results suggest that Lcn2 is highly associated with the promotion of colorectal cancer metastasis to the liver, most likely secreted from liver cells, with increased levels connected to the advancement of metastatic progression in vitro through the use of a highly metastatic mouse model.

After the construction, verification, and large-scale endotoxin-free purification of pSecTagA-Lcn2, this plasmid was utilized in in vivo electroporation of control groups PBS only, 10 μg of pSecTagA vector only, and 10 μg of experimental group pSecTagA-Lcn2 in order to explore the effectiveness of this method for the stable transfer and constant expression of Lcn2 within the blood stream. After 6 days, the experimental group expresses the greatest concentration of Lcn2 in comparison to both controls. In vivo electroporation seems to be a viable method of continuously overexpressing Lcn2 in order to further examine colon cancer metastasis to the liver, though further studies must take place to identify the ideal dosage for maximized overexpression.

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