title: 2-Methoxyestradiol inhibits the proliferation and migration and reduces the radioresistance of nasopharyngeal carcinoma CNE-2 stem cells via NF-κB/HIF-1 signaling pathway inactivation and EMT reversal.
abstract: Accumulating evidence indicates that cancer stem cells (CSCs) are a source of resistance to radiation therapy (RT); however, the mechanism of this resistance remains unclear. 2-Methoxyestradiol (2-ME2) is a metabolic product of estrogen in the body. Recent studies have found that 2-ME2 regulates the activation of transcription factors, including nuclear factor (NF)-κB/hypoxia-inducible factor-1 (HIF-1), thus contributing to tumor cell apoptosis and chemosensitivity. Therefore, 2-ME2 is being studied as a potential anticancer drug. The purpose of this study was to determine the effect and mechanism by which 2-ME2 inhibits nasopharyngeal carcinoma CNE-2 stem-like cell (NPCSC) proliferation and migration and reduces NPCSC radioresistance. This study has important significance for reducing the radioresistance of these cells to improve the cure rate of NPC. First, the NPCSCs were collected in a serum-free culture system and then identified by relevant experiments. The NPCSCs were treated with 2-ME2 (0-8 µM) combined with X-ray exposure and Cell Counting Kit-8 (CCK-8), Transwell assay, colony formation assay, western blot analysis, RT-PCR, flow cytometry and RNA interference technology were used to explore the effect and mechanism of 2-ME2 on NPCSCs. The results showed that the microspheres collected in the serum‑free culture system possessed CSC traits and radioresistance. 2-ME2 obviously inhibited NPCSC growth and migration and reduced NPCSC radioresistance. 2-ME2 decreased NF-κB p65 and HIF-1α protein expression, downregulated NF-κB p65 nuclear localization, and reversed epithelial-mesenchymal transition (EMT). NF-κB p65 knockdown reduced HIF-1α expression, reversed EMT, and enhanced the suppressive effect of 2-ME2 on NPCSCs. Collectively, these data indicate that 2-ME2 inhibits NPCSC proliferation and migration and reduces the radioresistance of NPCSCs via NF-κB/HIF-1 signaling pathway inactivation and EMT reversal.
authors.affiliation: Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Shun-Long
authors.initials: SL
authors.lastname: Wu
authors.affiliation: Zunyi Medical College, Zunyi, Guizhou 563000, P.R. China.
authors.forename: Ya-Jun
authors.initials: YJ
authors.lastname: Li
authors.affiliation: Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Kui
authors.initials: K
authors.lastname: Liao
authors.affiliation: Department of Oncology, Affiliated Hospital of Zunyi Medical College, Zunyi, Guizhou 563000, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.affiliation: Department of Oncology and Radiation Medicine, College of Basic Medicine, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Department of Oncology and Radiation Medicine, College of Basic Medicine, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Oncology, Affiliated Hospital of Zunyi Medical College, Zunyi, Guizhou 563000, P.R. China.
authors.forename: Yao-Yao
authors.initials: YY
authors.lastname: Hu
authors.affiliation: Department of Oncology and Radiation Medicine, College of Basic Medicine, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Shao-Lin
authors.initials: SL
authors.lastname: Li
authors.affiliation: Department of Radiotherapy, Chongqing Cancer Institute, Chongqing 400030, P.R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000077584:2-Methoxyestradiol; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects; D002465:Cell Movement / Q000187:drug effects / Q000528:radiation effects; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D015536:Down-Regulation; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects* / Q000528:radiation effects; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics; D011836:Radiation Tolerance / Q000187:drug effects*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D050257:Tubulin Modulators / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016328:NF-kappa B; D012333:RNA, Messenger; D050257:Tubulin Modulators; D004958:Estradiol; D000077584:2-Methoxyestradiol