Meta-Analysis of Body Concentration of Polychlorinated Biphenyls and Prostate Cancer

Associations between polychlorinated biphenyls and cancer risk among type 2 diabetes: The modifying effects of lifestyle

A growing percentage of diabetes-related deaths has been attributed to cancer, with environmental factors playing important contributions. Thus, we studied the potential relationship between endocrine disruptors polychlorinated biphenyls (PCBs) and cancer risk in diabetes. We aimed to evaluate the association between serum seven indicator-PCB (PCB-28/52/101/118/138/153/180) levels and incident cancer, and further explore the possible modifying role of lifestyle. A total of 2806 type 2 diabetes mellitus (T2DM) cases were included from the Dongfeng-Tongji cohort at the baseline in 2008 and tracked until December 2018, and 320 incident cancers were identified during about 10-year follow-up. Cox proportional hazards models and competing risk regression models were used to reveal associations of baseline concentrations of PCBs with total cancer and specific cancer, respectively. Lifestyle score was determined by body mass index, waist circumference, physical activity, smoking, alcohol drinking, and diet. Each interquartile range (IQR) increment of non-dioxin-like PCBs (NDL-PCBs) generated an 8%-30% increase in cancer incidence. Individuals in the highest quartile for PCB-52, PCB-101, PCB-138, and lowly chlorinated PCBs had 1.44- to 1.68-fold higher cancer risk compared to those in the lowest quartile. Restricted cubic spline analyses and the quantile g-computation model showed similar results. Significant interactions were found between PCBs and fasting blood glucose or simplified insulin resistance assessment indicators. NDL-PCBs were positively and significantly associated with gastrointestinal cancer and respiratory cancer, especially with liver cancer, colorectal cancer, and lung cancer. Higher PCBs showed a significant increase in total cancer risk among participants with an unhealthy lifestyle, however, no associations were observed in those with a relatively healthy lifestyle (Pinteraction < 0.05). Our findings indicated an increased cancer risk associated with NDL-PCBs, highlighted the role of a healthy lifestyle in potentially reducing adverse impact, and provided preliminary data for environmental and public health interventions to alleviate the risk of cancer among diabetes.

Theoretical Studies on the Quantitative Structure-Toxicity Relationship of Polychlorinated Biphenyl Congeners Reveal High Affinity Binding to Multiple Human Nuclear Receptors

Polychlorinated biphenyls (PCBs) are organic chemicals consisting of a biphenyl structure substituted with one to ten chlorine atoms, with 209 congeners depending on the number and position of the chlorine atoms. PCBs are widely known to be endocrine-disrupting chemicals (EDCs) and have been found to be involved in several diseases/disorders. This study takes various molecular descriptors of these PCBs (e.g., molecular weight) and toxicity endpoints as molecular activities, investigating the possibility of correlations via the quantitative structure-toxicity relationship (QSTR). This study then focuses on molecular docking and dynamics to investigate the docking behavior of the strongest-binding PCBs to nuclear receptors and compares these to the docking behavior of their natural ligands. Nuclear receptors are a family of transcription factors activated by steroid hormones, and they have been investigated to consider the impact of PCBs on humans in this context. It has been observed that the docking affinity of PCBs is comparable to that of the natural ligands, but they are inferior in terms of stability and interacting forces, as shown by the RMSD and total energy values. However, it is noted that most nuclear receptors respond to PCBs similarly to how they respond to their natural ligands-as shown in the RMSF plots-the most similar of which are seen in the ER, THR-β, and RAR-α. However, this study is performed purely in silico and will need experimental verification for validation.