Genotoxicity

Anti-Pollution Matrix > Damage > Molecular > Genotoxicity

Explanation

Genotoxicity refers to the effects of chemical substances, physical factors or biological noxae on the genetic material of cells. DNA or RNA can be affected. Pollution can induce the generation of free radicals (so-called reactive oxygen species, ROS), which cause a variety of DNA damages, such as DNA single and double strand breaks, base modifications and "abasic sites" (= sites in DNA that contain neither purines nor pyrimidines, base-less). 8-Hydroxydeoxyguanosine (8-OHdG) represents one of the possible forms of oxidative DNA modifications and results from the hydroxylation of deoxyguanosine. Cyclobutane-pyrimidine dimers (CPD) and 6-4 photoproducts (6-4PP) are also possible consequences due to the action of exogenous factors [1].

In the context of genotoxicity and pollution, sunlight plays a major role, but soot or chemical carcinogens such as aromatic polycyclic hydrocarbons on particulate matter are important sources [2].

 

Effects on the skin

If a substance has a genotoxic effect, chromosome abberations or gene mutations may occur (see above). Transformations of normal cells into malignant cancer cells (tumor induction, carcinogenesis) may occur. The expression of genes regulating cell growth (proliferation and differentiation) can be modulated. Basal cell carcinoma (BCC) is the most common form of skin cancer. This carcinoma arises from the basal cells, which are located at the bottom of the epidermis. Squamous cell carcinoma (SCC) is the second most common skin tumor after basal cell carcinoma. Long-term exposure to sunlight can be indicated as the cause. The effect of this can be intensified by pollution. But also a pre-damage of the skin by pollution, like tar, arsenic or soot as well as chemical carcinogens, like aromatic hydrocarbons can induce a BCC or SCC [2]. A precursor caused by genotoxicity in the skin is actinic keratosis, which is characterized by scaly, rough and often itchy skin.

 

Measures

Preventive measures can be found under the individual pollutants.

 

Impact detection methods

Examination of chromosomal aberrations (FISH, fluorescence in situ hybridization), determination of the frequency of a sister chromatid exchange, detection of DNA damage in cells (=comet assay). Antibodies can be used here that can detect, for example, 8-oxodG mutations, CPDs or 6-4-PP.

PCR (polymerase chain reaction) to detect gene mutations in a single base.

 

References

[1] H.L. Lo, S. Nakajima, L. Ma, B. Walter, A. Yasui, D.W. Ethell, L.B. Owen, Differential biologic effects of CPD and 6-4PP UV-induced DNA damage on the induction of apoptosis and cell-cycle arrest, BMC Cancer, 5 (2005) 135, https://doi.org/10.1186/1471-2407-5-135
[2] D. Didona, G. Paolino, U. Bottoni, C. Cantisani, Non Melanoma Skin Cancer Pathogenesis Overview, Biomedicines, 6 (2018), DOI: 10.3390/biomedicines6010006