Study On The Correlation Between The High Incidence Of Female Lung Cancer And Environmental Iron In Xuanwei Area Of Yunnan Province

Objective（s）To study the migration and enrichment routes of iron elements in bituminous coal widely used in areas with high incidence of lung cancer in Xuanwei,and explore whether there is a pathogenic process of "bituminous coal combustion-iron containing coal smoke inhalation-iron overload in the body-cell ferroptosis（ROS accumulation）-lung cancer occurrence",providing reference for the prevention and treatment of high incidence of lung cancer in this area.Methods1.X-ray energy spectroscopy was performed to analyze whether the surface of silica particles released from the combustion of raw coal in Xuanwei area into the indoor air was enriched with iron.2.Confirmation of the presence of iron-containing（Fe）particles deposited in lymph nodes of female lung cancer patients in Xuanwei area by Prussian blue staining.3.Western-Blot detection of iron transport-related proteins transferrin 1（Transferrin1,Tf1）,transferrin 2（Transferrin2,Tf2）and glutathione peroxidase,a core gene of the cellular ferroptosis pathway,in the postoperative lung tissues of 20 female lung adenocarcinoma patients from rural Xuanwei area and 20 female lung adenocarcinoma patients from non-Xuanwei area 4（Glutathione Peroxidase 4,GPX4）protein content.4.Collect and make transmission electron microscopic observation sections of lung cancer tissue,paracancerous tissue,and normal lung tissue.The mitochondrial morphology of cells was observed by transmission electron microscopy to find evidence related to the occurrence of ferroptosis in cells.5.Make 100μg/m L soot suspension and expose BEAS-2B cells to soot suspension;expose BEAS-2B cells to 100μg/m L 20 nm iron trioxide and observe the changes in cell morphology comparing the two conditions.Results1.In this study,we first found that iron was attached to the surface of silica particles in the form of ferrous oxide(Fe²⁺)nanoparticles by X-ray energy spectrometry.2.The specimens of surgically resected mediastinal lymph nodes from typical non-smoking female lung cancer patients in Xuanwei,Yunnan Province,with high incidence of lung cancer,were selected and confirmed by Prussian blue staining to have large deposits of iron（Fe）-containing particles in the lymph nodes.3.The Tf1 and Tf2 contents in lung tissues were detected by Western-Blot technique,and the Tf1 protein content in the Xuanwei group was higher than that in the non-Xuanwei group（P < 0.01）,while the Tf2 protein content in the Xuanwei group was lower than that in the non-Xuanwei group（P < 0.01）.GPx4 protein content in the Xuanwei group was lower than that in the non-Xuanwei group,but there was no statistical difference（P > 0.05）.4.Transmission electron microscopy showed that there was cellular "ferroptosis"（smaller mitochondria and increased bilayer density）in the cancer cells and normal cells of the paracancerous tissue.5.The morphological changes of BEAS-2B cells after 24h（A）,48h（B）and 72h（C）hours of exposure to 100μg/m L soot suspension were consistent with the morphological changes of BEAS-2B cells after 24h（A）,48h（B）and 72h（C）hours of exposure to 100μg/m L 20 nm iron trioxide.Conclusion（s）In this study,the relationship between the development of lung cancer in Xuanwei,Yunnan Province and environmental iron was preliminarily confirmed,in which divalent iron ions in the environment caused iron overload through adsorption and silica,and regulated the expression level of iron transport-related proteins in the body;meanwhile,the phenomenon of cellular " ferroptosis " existed in the cancer and paracancerous tissues of female lung cancer patients in Xuanwei,Yunnan Province.