Apoptosis

The dauer larva is an alternate larval stage which allows the nematode C. elegans to survive environmestress during development. Dauer formation requires autophagy, a cellular process responsible for degrading and recycling cytoplasmic components. I investigated the role of a spinster orthiolog, C13C4.5, by examining the effects of C13C4.5 loss-of-function and by generating a transgenic strain which expressed a C13C4.5::GFP fusion protein. Under normal conditions C13C4.5::GFP is expressed diffusely in the intestine, but under autophagy-promoting conditions the expression pattern becomes more punctate. This is consistent with localization of C13C4.5 to autophagolysomoes during autophagy, as has been shown for spinster in D. melanogaster. Loss of C13C4.5 function in a dauer-constitutive mutant resulted in a reduction in the proportion of animals entering into the dauer stage. Together these data suggest that C13C4.5 is involved in dauer formation and the autophagy pathway.

Tumor cells are characterized by an increase in genomic instability, brought about by both chromosomal rearrangement and chromosomal instability. Both of these broad changes can be induced by exposure to carcinogens. During mitosis, cells can exhibit early and late lagging chromosomes, multipolar spindles or anaphase bridges, all of which contribute to genomic rearrantement. We have studied the link between exposure to carcinogen and prevalence of mitotic defect in both chromosomally stable and unstable cell lines as well as ecamined the restorative effects of antioxidants in preventing mitotic defects. We have exposed MES-SA uterine cancer cells to vinyl chloride followed by exposure to an antioxidant : ascorbic acid, B-carotene, or lycopene. Treated cells were then scored for the prevalence of mitotic defects within the population and compared to controls. We have also investigated whether pre-treatment with the antioxidants will weaken the effects of carcinogen exposure in these cell lines.

Dichloroacetate (DCA) is a chemical with potential to be a cancer therapy due to its ability to treat mitochondrial metabolic disorders. Previous studies have affirmed DCA's ability to target cancer cells, leaving healthy cells unharmed (Bonnet et al., 2007). Javonia Washington continued research that Bonnet et al. began by testing DCA's effectson a greater number of cell types (Washington, 2008). This project collects and analyzes the data generated by Washington's research using the computer programs Excel and SPSS. The analysis shows that DCA concentration is vital when considering the chemical as an anti-cancer drug ; it had a significant effect on the cancerous cells from 0.5mM and higher, but both cancerous and non-cancerous cells died at similar rates when the concentration reached 10mM. Further, DCA affects some cancer cells more quickly than others, which could increase the risk of harming surrounding healthy cells if used improperly as a cancer treatment.

The progression of cancerous cells towards a more aggressive tumor can be linked to external elements called carcinogens. The goal of this project is to examine the correlation between exposure to specific carcinogens and an increase of mitotic defects. These defects can manifest as lagging chromosomes, multipolar spindles, and anaphase bridges. Some of these instabilities are associated with the formation of reactive oxygen species (ROS), which are known to damage DNA. The potential for damage to the genome can be averted via antioxidants. Using the oral cancer cell line UPCI:SCC103, we established a baseline for the mitotic defects in the absence and presence of various ROS-inducing carcinogens using DAPI-stained fixed cells examined by immunofluorescent microscopy, The cells were treated with varying concentrations of the antioxidants, Vitamin C, (Sb(B-Carotene, and Vitamin E. The reactive oxygen scavengers significantly reduced the number of mitotic defects. A possible link between the carcinogens and lagging chromosomes was established.