Publication Date

8-2014

Date of Final Oral Examination (Defense)

7-3-2014

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Chemistry

Department

Chemistry

Supervisory Committee Chair

Don L. Warner, Ph.D.

Supervisory Committee Member

Ken Cornell, Ph.D.

Supervisory Committee Member

Kristen Mitchell, Ph.D.

Abstract

Aziridinomitosenes (AZMs) are organic compounds structurally related to the mitomycins, a class of anti-tumor agents and antibiotics. The cytotoxicity of the mitomycins is correlated to their ability to covalently link complimentary strands of DNA, forming DNA interstrand cross-links (ICLs). Currently, there has been limited investigation into the biological activity of AZMs, likely due to difficulties in their synthesis. Our lab has synthesized and evaluated the cellular effects of two AZMs, (1S, 2S)-6-desmethyl(methylaziridino)mitosene (H/H-AZM) and (1S, 2S)-6-methyl(methylaziridino)mitosene (Me/H-AZM). We hypothesize that AZMs exhibit their cytotoxicity and cellular effects following a similar pathway to that of mitomycin C (MC) including the ability to form ICLs and modify DNA in cellular systems. To test this hypothesis, we evaluated the cytotoxicity of our AZMs compared to MC in six cancer cell lines. Previously, MC has also been shown to lead to the production of reactive oxygen species (ROS), activation of caspase enzymes, changes in mitochondrial membrane potential, and nuclear swelling. As such, we probed for these effects in Jurkat and HeLa cancer cells upon AZM and MC treatment. Our studies reveal that the Me/H-AZM has increased cytotoxicity compared to MC, while H/H-AZM was only more potent than MC in the T47D breast cancer cell line. Both AZMs were more effective at increasing the levels of oxidative stress over MC. Changes to the mitochondrial membrane potential were equivalent or greater than MC in treatments with both AZMs. Additionally, all three compounds were found to increase caspase-3 activation, with MC leading to the greatest amount of activity in the Jurkat cell line. Only MC treatment significantly increased caspase-3 activation in HeLa cells. Both AZM and MC treatment stimulated nuclear swelling. Finally, the DNA modifying-abilities of AZMs were investigated with the use of a Hoechst 33342 DNA cross-linking assay and a modified alkaline COMET assay. Of the three compounds tested, these studies found that Me/H-AZM lead to highest formation of DNA-DNA cross-links and modification to cellular DNA. H/H-AZM treatment was found to produce a larger amounts of cross-links and DNA modification in Jurkat cells than MC, but showed similar results to MC in HeLa cells. Overall, AZMs were found to possess similarities to MC in their cellular effects in Jurkat and HeLa cells, with the ability to alkylate DNA in cell systems.

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