Date of Submission
7-2021
Document Type
Thesis
Degree Name
Master of Science in Cellular and Molecular Biology
Department
Biology and Environmental Sciences
Advisor
Alireza G. Senejani, Ph.D.
Committee Member
Christina Zito, Ph.D.
Committee Member
Anna Kloc, Ph.D.
Keywords
Folic Acid Fortification Programs, Synthetic Folic Acid, Embryonic Fibroblast Cells, DNA Modification, Impaired DNA Repair Genes
MeSH
Folic Acid, Neoplasms, DNA Damage, DNA Repair, Genomic Instability, DNA-Directed DNA Polymerase, Apoptosis
LCSH
Folic acid, Cancer, DNA damage, DNA repair, DNA polymerases, Apoptosis
Abstract
Mandatory folic acid (FA) fortification programs have been introduced in many countries since 1998 [1]. This fortification program, especially when combined with vitamin supplements taken for health purposes, can lead to higher-than-normal levels of synthetic FA in the body [2]. Recent research has linked high levels of synthetic FA (more than the daily requirement of 400μg/day) with increased incidences of cancer [2-7]. In comparison, low levels of FA have been shown to cause DNA damage due to impaired DNA repair processes [8,9]. This study hypothesizes that increased levels of FA give rise to DNA modification. Therefore, if cells harbor an impaired DNA repair system, this can cause accumulation of aberrant DNA modification leading to genomic instability, which is a characteristic of cancers. The effect of different concentrations of FA was evaluated on wild type mouse embryonic fibroblast cells (MEF-WT) and DNA Polymerase β deficient MEFs (MEF-Polβ-/-). Data from AlamarBlue Cell viability assay suggested that FA treatment reduces the viability of the cell lines starting from 24 hours and was optimal at 5mg/mL (11.3mM). This cell death was revealed to be mainly due to apoptosis with Annexin-FITC/PI flow cytometry assay, with MEF-Polβ-/- cells demonstrating significantly higher number of apoptotic cells (2-fold) compared to the control. When allowed to recover, the extent of apoptosis in MEF-Polβ-/- cells increased further (4-fold), indicating that FA might damage cells permanently. Additionally, cell cycle studies showed that - FA treatment arrested the cell lines at the G1 phase of cell cycle and removal of treatment drove only MEF-Polβ-/- cells into a G2 arrest. Furthermore, single strand breaks in the genome significantly increased for MEF-WT (3-fold) and MEF-Polβ-/- (10-fold) cell lines after 24 hours of treatment while double strand breaks significantly increased 19.1% (0.2-fold) only in MEF-Polβ-/- cells. These assessments have shown that FA affects the cells when present in high levels and that cells with impaired DNA repair genes are more sensitive to it. This study will urge further research on synthetic FA on cancer due to impaired BER DNA repair system and on creating public awareness for moderate FA consumption.
Recommended Citation
Madhavan, Suneeti, "Evaluating Effect of Folic Acid on Mouse Embryonic Fibroblast Cells with Impaired DNA Repair System" (2021). Master's Theses. 179.
https://digitalcommons.newhaven.edu/masterstheses/179