Discipline: Biological Sciences
Subcategory: Physiology and Health
Rajendra Neupane - Benedict College
Co-Author(s): William McAmis Jr. and Samir Raychoudhury, Benedict College, Columbia, SC
Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous and persistent environmental contaminants. Some of them are suspected carcinogens and may affect the reproductive systems as potential endocrine disruptors or may have direct toxic effects on human. The objective of this study is to measure the severity of toxicity and compare cell viability in two different types of human breast cancer cells (estrogen receptor negative MDA-MB-231 cells and estrogen receptor positive MCF7 cells) by conducting Lactate Dehydrogenase (LDH) and MTT Assays. We hypothesize that the cells with positive estrogen receptors may be more susceptible to the damaging effects. The study was performed using triplicate samples in 96- well plates. Cultured cells were incubated in the presence of medium alone, medium containing 1.14% acetonitrile (both as vehicle controls), or in the presence of a mixture of PAHs (500nM, 2µM and 5µM). The exposure media were prepared by serial dilutions. Both human breast cancer cells were first exposed to various concentrations of PAHs for 24 hours and then the cell viability assays were performed. Both of these assays give colored formazan compound as the final product by the reduction of the substrate. The optical density (OD) of formazan compound represents damaged cells in LDH Assay and live/dead cells in MTT Assay. In both cell types, higher concentrations of PAHs damaged more cells leaving less viable cells in the sample. In addition, MDA-MB-231 cells appeared to be more resistant to PAHs than MCF 7 Cells. In terms of cell viability, we did not observe any significant difference between the two cell types when exposed to 5µM PAHs. However with LDH Assay, the severity of toxicity was two times higher in MCF-7 cells when compared to MDA-MB-231 cells upon exposure to 5µM PAHs. These data suggest that the PAHs are toxic to breast cancer cells, but the degree of severity differs. Future work includes performing additional experiments on two different human breast cancer cell lines and on rat liver macrophage cells in order to examine the mechanism of action of this varied toxic effect of PAHs on the cells.
Not SubmittedFunder Acknowledgement(s): Funding was provided by NSF / HBCU-UP grant to Dr. Samir Raychoudhury Grant No: HRD 1436222
Faculty Advisor: Samir Raychoudhury, PhD, Samir.Raychoudhury@benedict.edu
Role: Literature review, Preparation of media (by serial dilution), cell culture, cell passage, cell exposure, MTT and LDH assays, data analysis, data representation, Research presentation