Response of Triple-Negative Breast Cancer Cell Lines after Exposure to the Heavy Metal Mercury

Student Classification


Faculty Mentor

Dr. P. Smith



Document Type


Publication Date

Spring 2019


Triple-Negative Breast Cancer (TNBC) accounts for 15 percent of all breast cancers. It is characterized by cancer cells that lack the expression of estrogen, progesterone, and HER2/Neu receptors. Heavy metals such as mercury have been reported to have toxic effects on living organisms including humans and may pose an increased risk to diseases such as breast cancer. While environmental exposures to toxins such as mercury have been speculated to play a role in causing cancer, the consequences of mercury exposure on breast cells have not been fully assessed, and here we are interested in assessing the cytotoxic and molecular effects that mercury ions have on human breast cells. We exposed human breast cell lines to various concentrations of mercury and revealed a differential cytotoxic response. We used triple-negative breast cancer cell lines (HCC70, HCC1806), and a luminal A cell line (HCC1500) and revealed that they all had an increase in cell death as the concentration of mercury increased with a classic dose response using light microscopy and cell viability assays. We also performed a time-course over 48-72 hours revealing that even at lower concentrations the cells died as the time of exposure increased. We also verified using flow cytometry cell cycle arrest and cell death after exposure to mercury. In conclusion, mercury has a cytotoxic effect on human breast cells and may pose a risk to increasing the genetic instability of breast cells, but it may also be possible in the future to take advantage of its toxicity to elicit the death of breast cancer. We plan on assessing the molecular response of the p53-microRNA pathway network in these breast cancer cells to mercury exposure to determine the role that it may play in its cytotoxic effects.

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