The influence of occupational exposure to PAHs on the blood plasma levels of p53 and p21WAF1 proteins

Correlation of Occupational Exposure to Carcinogenic Polycyclic Aromatic Hydrocarbons (cPAHs) and Blood Levels of p53 and p21 Protiens

Carcinogenic polycyclic aromatic hydrocarbons (cPAHs) are considered the most serious cancer risk. This study was conducted to assess the effect of acute exposure to cPAHs on cancer biomarker proteins p53 and p21 in occupational workers during the hajj season in Makkah. One hundred five participants were recruited, including occupational workers and apparently healthy individuals; air samples were collected using personal sample monitors to identify the subjects’ exposure to cPAHs. Quantitative analyses of benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF), benzo(a)pyrene (BaP), dibenzo(a,h)fluronathene (DBA), indeno(1,2,3-c,d)pyrene (IND) and chyresene (CRY) were carried out using the GC/Mass technique. Serum p53 and p21 proteins were analyzed using ELISA. The ambient air samples collected by the occupationally exposed group were more highly polluted by cPAHs, (90.25 ± 14.1) ng/m³, than those of the unexposed control groups, (30.12 ± 5.56) ng/m³. The concentration of distributive cPAHs was markedly more elevated in the air samples of the exposed group than in those taken from the non-exposed group. The study results demonstrated significant links between short-term exposure to cPAHs and serum p53 and p21 levels. Serum p53 and p21 proteins potentially influence biomarkers when exposed to ambient air cPAHs.

Oncogene and tumor-suppressor gene products as serum biomarkers in occupational-derived lung cancer

Since lung cancer is the most frequent occupational cancer and one of the leading causes of cancer mortality in the world, it is one of the biggest challenges for research. In the literature, there are inconsistent results regarding the utility of the serum biomarkers p53, anti-p53 antibodies, EGF receptor or Ras. Based on the published results, routine use of these biomarkers for detection of occupationally derived lung carcinomas is not currently recommended. In this review, we summarize the literature and discuss the relevance of these oncogene and tumor-suppressor gene products as serum biomarkers in occupational-derived lung cancer.

Air pollution by carcinogenic PAHs and plasma levels of p53 and p21(WAF1) proteins

We analyzed the effect of exposure to carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in ambient air on the plasma levels of p53 and p21(WAF1) proteins among city policemen, bus drivers and controls in three European cities: Prague (Czech Republic), Kosice (Slovakia) and Sofia (Bulgaria). p53 and p21(WAF1) proteins are key regulators of the cell cycle and are accepted as universal markers of genotoxic stress and DNA damage. In total 204 exposed subjects (100 smokers, 104 nonsmokers) and 152 controls (54 smokers, 98 nonsmokers) were analyzed. Personal exposure to c-PAHs was evaluated using personal samplers during the working shift. The levels of p53 and p21(WAF1) proteins were assessed by ELISA assay. There were no differences between the levels of either protein between exposed and controls, or smokers and nonsmokers, in any city. However, we observed significant differences in p53 plasma levels in all subjects regardless of the exposure status between the individual cities (median values: 5, 31, 234pg/ml, p<0.001, for Prague, Kosice and Sofia, respectively). The levels correspond to the differences in exposure levels to c-PAHs and benzo[a]pyrene (B[a]P) in the individual cities. A multiple linear regression analysis confirmed that c-PAHs exposure is a variable significantly affecting levels of both proteins in all locations. When all subjects were divided into the group exposed to below-median levels of c-PAHs and the group exposed to above-median levels of c-PAHs we found significantly higher p53, as well as p21(WAF1) levels in the above-median exposure group (p53, 167pg/ml versus 25pg/ml, p<0.001; p21(WAF1), 2690pg/ml versus 2600pg/ml, p<0.05). Among all subjects p53 plasma levels were positively correlated with p21(WAF1) levels, exposure to B[a]P, c-PAHs and levels of total DNA adducts; for p21(WAF1) levels we observed the positive correlation with cotinine, c-PAHs exposure, total and B[a]P-like DNA adduct levels. In conclusion our results suggest that p53 and p21(WAF1) proteins plasma levels may be useful biomarkers of c-PAHs environmental exposure.

Comparison of p53 levels in lymphocytes and in blood plasma of nuclear power plant workers

p53 levels were assessed in lymphocytes and in blood plasma of workers from two Czech nuclear power plants (NPP): 114 subjects working in Temelin and 108 subjects working in Dukovany. Ionizing radiation (IR) exposure data were available for 64 and 59 subjects working in the monitored zones from the NPP in Temelin and Dukovany, respectively. The short-term doses of IR for these subjects were 0.01 and 0.12 mSv, and the long-term doses were 0.46 and 5.68 mSv, in the Temelin and Dukovany NPP, respectively. As a control group, 46 subjects living in Ceske Budejovice, a city nearby the Temelin NPP, were analyzed. The concentration of p53 in lymphocytes was significantly higher in workers from the monitored zone in the Dukovany NPP (median value 6.4 pg/microg protein, P <0.001) than in workers from the Temelin NPP (3.2 pg/microg) as well as in the control group (3.5 pg/microg). In contrast, plasma levels of p53 were comparable in the control group (median value 116 pg/ml plasma) and workers from the monitored zone of Dukovany NPP (102 pg/ml), but lower in workers from Temelin NPP (5 pg/ml). Other factors affecting p53 levels were studied. Smoking resulted in increased p53 lymphocyte levels. The effect of polymorphisms in metabolic and DNA repair genes on p53 levels was analyzed. The correlation was found between p53 levels in lymphocytes and p53 codon 72 polymorphism in subjects working in NPPs, but not in the control group. The results of measurement p53 levels in lymphocytes suggest that this biomarker could reflect the short-term as well as long-term effects of low doses IR. Its impact on human health should be further explored.