Title:The Psychiatric Drug Lithium Increases DNA Damage and Decreases Cell Survival in MCF-7 and MDA-MB-231 Breast Cancer Cell Lines Expos ed to Ionizing Radiation
Volume: 12
Author(s): Maryam Rouhani*, Samira Ramshini and Maryam Omidi
Affiliation:
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731,Iran
Keywords:
Lithium, breast cancer, radiosensitizer, DNA damage, glycogen synthase kinase-3 beta, ionizing radiation.
Abstract:
Background: Breast cancer is the most common cancer among women. Radiation therapy
is used for treating almost every stage of breast cancer. A strategy to reduce irradiation side effects and
to decrease the recurrence of cancer is concurrent use of radiation and radiosensitizers. We studied the
effect of the antimanic drug lithium on radiosensitivity of estrogen-receptor (ER)-positive MCF-7 and
ER-negative, invasive, and radioresistant MDA-MB-231 breast cancer cell lines.
Methods: MCF-7 and MDA-MB-231 breast cancer cell lines were treated with 30 mM and 20 mM
concentrations of lithium chloride (LiCl), respectively. These concentrations were determined by
MTT viability assay. Growth curves were depicted and comet assay was performed for control and
LiCl-treated cells after exposure to X-ray. Total and phosphorylated inactive levels of glycogen
synthase kinase-3beta (GSK-3β) protein were determined by ELISA assay for control and treated
cells.
Results: Treatment with LiCl decreased cell proliferation after exposure to X-ray as indicated by
growth curves of MCF-7 and MDA-MB-231 cell lines within six days following radiation. Such
treatment increased the amount of DNA damages represented by percent DNA in Tails of comets at
0, 1, 4, and even 24 hours after radiation in both studied cell lines. The amount of active GSK-3β
was increased in LiCl-treated cells in ER-positive and ER-negative breast cancer cell lines.
Conclusion: Treatment with LiCl that increased the active GSK-3β protein, increased DNA damages
and decreased survival independent of estrogen receptor status in breast cancer cells exposed to
ionizing radiation.