Environmental Pesticides and Heavy Metals — Role in Breast Cancer

Abstract

The intent of this chapter is to provide an overview to the current thoughts and ideals regarding the involvement of pesticides and heavy metals in the progress of breast cancer. The history of pesticides encompasses a few millennia, but our understanding of the pesticide action and the health consequences has only begun to develop in the last -years. Interestingly, many of these pesticides have estrogen-like activity and may be involved in the development of breast cancer. " new category of estrogen-like compounds has been identified and studied in the last years, the metalloestrogens . Heavy metals, such as cadmium, which have estrogen like activity will be discussed. Finally, we will attempt to pull together the actions of pesticides and metalloestrogens as a possible synergistic mechanism by which these toxins may work to promote breast cancer development.

Toxic-Metal-Induced Alteration in miRNA Expression Profile as a Proposed Mechanism for Disease Development

“…Although these metals are naturally occurring elements found in the earth's crust, their concentrations in soil, air, and water have increased to exceed natural occurrence levels as a result of metal mining and manufacturing, agriculture, and other anthropogenic activities. These metals are utilized during a variety of manufacturing processes and often comprise the majority of the environmental pollutants [1]. Once released into the environment, these pollutants cannot be destroyed but rather are altered chemically, changing their bioavailability and toxicity.…”

“…The toxicity of Hg in humans has been well studied, from the description of "mad hatter disease", where Hg-containing solutions utilized to treat the material used in hat-making resulted in mental changes in the hat maker, to current Hg-mediated cellular changes. Human exposure to Hg has been reported to be involved in the development of many cancers [1,2,40].…”

Effect of Cadmium on Worker Ovary Morphology of Bombus morio (Hymenoptera: Bombini)

“…At the molecular and biochemical levels, cadmium exerts its toxic effects by replacing the co-factor of the metalloenzymes and metalloestrogens, such as the metallothioneins, a group of enzymes involved in protecting the natural and essential metal ion homeostasis and also in controlling oxidative stress (Margoshes and Vallee, 1957;Ruttkay-Nedecky et al, 2013;Wallace, 2015). The enzyme co-factor can be substituted for a metal ion of similar size (e.g., zinc for cadmium) and this replacement prevents the enzymes from performing their functions.…”

“…Cadmium can also associate with non-metalloenzymes, interacting with the sulfhydryl radicals of cysteine-rich proteins (Margoshes and Vallee, 1957;Duruibe et al, 2007), such as vitellogenin (Piulachs et al, 2003). Thus, cadmium itself is a potent endocrine disruptor, cytoskeleton destabilizer and mutagenic agent (Godt et al, 2006;Wallace, 2015).…”

“…Cadmium (Cd), a by-product of zinc mining exploration, is one of the most dangerous trace metals and causes all sorts of damage, as mentioned above (Godt et al, 2006;Abdalla and Domingues, 2015;Wallace, 2015). Moreover, Cd can also be found as a component of agrochemicals, enhancing the harmful effects of such toxicants on the non-target entomofauna, especially bees (WHO, 2011;Wallace, 2015).…”