Screening of the differentially expressed proteins in malignant transformation of BEAS-2B cells induced by coal tar pitch extract.

Coal tar pitch extract (CTPE) was carcinogenic and could cause occupational lung cancer. Hence, we explored the changes of protein molecules during CTPE-induced malignant transformation (MT) of immortalized human bronchial epithelial (BEAS-2B) cells and provided clues for screening early biomarkers of CTPE-associated occupational lung cancer. The MT model of BEAS-2B cells induced by CTPE with 15.0 μg/mL. Subsequently, the MT of the BEAS-2B cells was verified by morphological observation, cell proliferation test, plate colony formation assay, and cell cycle assay. At the end of the experiment, we explored the differentially expressed proteins (DEPs) by total protein tandem mass tags quantitative proteomics technique between DMSO40 cells and CTPE40 cells. It was found that the proliferation ability, and colony formation rate were enhanced, and the cell cycle was changed. Then, bioinformatics analysis showed that a total of 107 DEPs were screened between CTPE40 and DMSO40 cells, of which 74 were up-regulated and 33 were down-regulated. As a result, 6 hub proteins were screened by protein-protein interaction network analysis. The expression levels of COX7A2, COX7C, MT-CO2, NDUFB4, and NDUFB7 were up-regulated as well as the expression of RPS29 protein was down-regulated. In summary, we established an MT model and explored the changes in protein molecules. As a result, this study suggested that changes of protein molecules, including COX7A2, COX7C, NDUFB7, MT-CO2, NDUFB4, and RPS29, occurred at the stage of BEAS-2B cell malignancy following CTPE exposure, which provided key information for screening biomarkers for CTPE-related occupational lung cancer.