Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH) , Texas Tech University , Lubbock , Texas , United States.
Chem Res Toxicol. 2019 Jun 17;32(6):1299-1309. doi: 10.1021/acs.chemrestox.9b00089. Epub 2019 Jun 4.
Arsenic contamination is a serious environmental and public health issue worldwide including the United States. Accumulating evidence suggests that kidney is one of the target organs for arsenic-induced carcinogenesis. However, the mechanism of arsenic-induced renal carcinogenesis is not well understood. Therefore, the objective of this study was to evaluate the carcinogenicity of chronic exposure to an environmentally relevant concentration of arsenic on kidney epithelial cells and identify the molecular mechanism underlying this process. HK-2 kidney epithelial cells were treated with arsenic for acute, long-term, and chronic durations, and cellular responses to arsenic exposure at these time points were evaluated by the changes in growth, morphology, and expression of genes. The results revealed a significant growth increase after long-term and chronic exposure to arsenic in HK-2 cells. The morphological changes of EMT and stem cell sphere formation were also observed in long-term arsenic exposed cells. The anchorage-independent growth assay for colony formation and cell maintenance in cancer stem cell medium further confirmed neoplastic transformation and the induced cancer stem cell properties of arsenic-exposed cells. Additionally, the expression of marker genes confirmed the increased growth, EMT, and stemness during arsenic-induced carcinogenesis. Moreover, the increase expression of β-catenin and c-Myc further suggested the role of these signaling molecules during carcinogenesis in HK-2 cells. In summary, results of this study suggest that chronic exposure to arsenic even at a relatively lower concentration can induce neoplastic transformation through acquisitions of EMT, stemness, and MET phenotypes, which might be related to the β-catenin/c-Myc signaling pathway.
砷污染是一个严重的环境和公共卫生问题,包括美国在内的全球范围内都存在这一问题。越来越多的证据表明,肾脏是砷致癌作用的靶器官之一。然而,砷诱导肾致癌的机制尚不清楚。因此,本研究的目的是评估慢性暴露于环境相关浓度的砷对肾脏上皮细胞的致癌作用,并确定这一过程的分子机制。用砷处理 HK-2 肾脏上皮细胞,急性、长期和慢性暴露于砷,通过基因表达变化评估砷暴露在这些时间点对细胞的反应。结果显示,HK-2 细胞长期和慢性暴露于砷后,细胞生长明显增加。在长期砷暴露的细胞中也观察到 EMT 和干细胞球形成的形态变化。在无锚定生长测定中,用于集落形成和癌细胞维持的培养基进一步证实了砷暴露细胞的肿瘤转化和诱导的癌症干细胞特性。此外,标记基因的表达证实了砷诱导致癌过程中细胞生长、EMT 和干细胞特性的增加。此外,β-catenin 和 c-Myc 的表达增加进一步表明了这些信号分子在 HK-2 细胞癌变过程中的作用。总之,本研究结果表明,即使在相对较低的浓度下,慢性暴露于砷也可以通过获得 EMT、干性和 MET 表型诱导肿瘤转化,这可能与β-catenin/c-Myc 信号通路有关。