Effects of Inorganic Arsenic on Human Prostate Stem-Progenitor Cell Transformation, Autophagic Flux Blockade, and NRF2 Pathway Activation.
| Autor: | Lishi Xie1,2, Wen-Yang Hu1,2, Dan-Ping Hu1, Guangbin Shi3, Ye Li1, Jianfu Yang4, Prins, Gail S.1,2,5,6 gprins@uic.edu |
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| Předmět: |
*Animal experimentation
*Arsenic *Homeostasis *Molecular biology *RNA *Water supply *Environmental exposure Autophagy Reactive oxygen species Analysis of variance Cellular signal transduction Culture media (Biology) Cultures (Biology) Epithelial cells Gene expression Genes Immunoassay Immunoblotting Lysosomes Mice Plasmids Polymerase chain reaction Prostate tumors Proteins Research funding Stains & staining (Microscopy) Statistics Stem cells T-test (Statistics) Transcription factors Data analysis Reverse transcriptase polymerase chain reaction Data analysis software Microarray technology Gene expression profiling Deoxyribonucleosides In vitro studies Colony-forming units assay In vivo studies Disease risk factors |
| Zdroj: | Environmental Health Perspectives. Jun2020, Vol. 128 Issue 6, p067008-1-067008-16. 16p. 7 Color Photographs, 1 Diagram, 1 Graph. |
| Abstrakt: | BACKGROUND: Inorganic arsenic (iAs) is an environmental toxicant associated with an increased risk of prostate cancer in chronically exposed populations worldwide. However, the biological mechanisms underlying iAs-induced prostate carcinogenesis remain unclear. OBJECTIVES: We studied how iAs affects normal human prostate stem-progenitor cells (PrSPCs) and drives transformation and interrogated the molecular mechanisms involved. METHODS: PrSPCs were enriched by spheroid culture from normal human primary or immortalized prostate epithelial cells, and their differentiation capability was evaluated by organoid culture. Microarray analysis was conducted to identify iAs-dysregulated genes, and lentiviral infection was used for stable manipulation of identified genes. Soft agar colony growth assays were applied to examine iAs-induced transformation. For in vivo study, PrSPCs mixed with rat urogenital sinus mesenchyme were grafted under the renal capsule of nude mice to generate prostatelike tissues, and mice were exposed to 5 ppm (~65 μM) iAs in drinking water for 3 months. RESULTS: Low-dose iAs (1 lM) disturbed PrSPC homeostasis in vitro, leading to increased self-renewal and suppressed differentiation. Transcriptomic analysis indicated that iAs activated oncogenic pathways in PrSPCs, including the KEAP1-NRF2 pathway. Further, iAs-exposed proliferative progenitor cells exhibited NRF2 pathway activation that was sustained in their progeny cells. Knockdown of NRF2 inhibited spheroid formation by driving PrSPC differentiation, whereas its activation enhanced spheroid growth. Importantly, iAs-induced transformation was suppressed by NRF2 knockdown. Mechanistically, iAs suppressed Vacuolar ATPase subunit VMA5 expression, impairing lysosome acidification and inhibiting autophagic protein degradation including p62, which further activated NRF2. In vivo, chronic iAs exposure activated NRF2 in both epithelial and stroma cells of chimeric human prostate grafts and induced premalignant events. CONCLUSIONS: Low-dose iAs increased self-renewal and decreased differentiation of human PrSPCs by activating the p62-NRF2 axis, resulting in epithelial cell transformation. NRF2 is activated by iAs through specific autophagic flux blockade in progenitor cells, which may have potential therapeutic implications. [ABSTRACT FROM AUTHOR] |
| Databáze: | GreenFILE |
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