Arsenic treatment increase Aurora-A overexpression through E2F1 activation in bladder cells

Yu Ting Kao, Chin Han Wu, Shan Ying Wu, Sheng Hui Lan, Hsiao-Sheng Liu, Ya Shih Tseng

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Abstract

Background: Arsenic is a widely distributed metalloid compound that has biphasic effects on cultured cells. In large doses, arsenic can be toxic enough to trigger cell death. In smaller amounts, non-toxic doses may promote cell proliferation and induces carcinogenesis. Aberration of chromosome is frequently detected in epithelial cells and lymphocytes of individuals from arsenic contaminated areas. Overexpression of Aurora-A, a mitotic kinase, results in chromosomal instability and cell transformation. We have reported that low concentration (≤1 μM) of arsenic treatment increases Aurora-A expression in immortalized bladder urothelial E7 cells. However, how arsenic induces carcinogenesis through Aurora-A activation remaining unclear. Methods: Bromodeoxyuridine (BrdU) staining, MTT assay, and flow cytometry assay were conducted to determine cell proliferation. Messenger RNA and protein expression levels of Aurora-A were detected by reverse transcriptional-PCR and Western blotting, respectively. Centrosome of cells was observed by immunofluorescent staining. The transcription factor of Aurora-A was investigated by promoter activity, chromosome immunoprecipitation (ChIP), and small interfering RNA (shRNA) assays. Mouse model was utilized to confirm the relationship between arsenic and Aurora-A. Results: We reveal that low dosage of arsenic treatment increased cell proliferation is associated with accumulated cell population at S phase. We also detected increased Aurora-A expression at mRNA and protein levels in immortalized bladder urothelial E7 cells exposed to low doses of arsenic. Arsenic-treated cells displayed increased multiple centrosome which is resulted from overexpressed Aurora-A. Furthermore, the transcription factor, E2F1, is responsible for Aurora-A overexpression after arsenic treatment. We further disclosed that Aurora-A expression and cell proliferation were increased in bladder and uterus tissues of the BALB/c mice after long-term arsenic (1 mg/L) exposure for 2 months. Conclusion: We reveal that low dose of arsenic induced cell proliferation is through Aurora-A overexpression, which is transcriptionally regulated by E2F1 both in vitro and in vivo. Our findings disclose a new possibility that arsenic at low concentration activates Aurora-A to induce carcinogenesis.

Original languageEnglish
Article number277
JournalBMC cancer
Volume17
Issue number1
DOIs
Publication statusPublished - 2017 Apr 18

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All Science Journal Classification (ASJC) codes

  • Oncology
  • Genetics
  • Cancer Research

Cite this

Kao, Y. T., Wu, C. H., Wu, S. Y., Lan, S. H., Liu, H-S., & Tseng, Y. S. (2017). Arsenic treatment increase Aurora-A overexpression through E2F1 activation in bladder cells. BMC cancer, 17(1), [277]. https://doi.org/10.1186/s12885-017-3253-1