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Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells
BACKGROUND: Neuroblastoma is the most common extracranial pediatric solid tumor. Intermittent hypoxia, which is characterized by cyclic periods of hypoxia and reoxygenation, has been shown to positively modulate tumor development and thereby induce tumor growth, angiogenic processes, and metastasis....
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4141796/ https://www.ncbi.nlm.nih.gov/pubmed/25148040 http://dx.doi.org/10.1371/journal.pone.0105555 |
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author | Bhaskara, Vasantha Kumar Mohanam, Indra Gujrati, Meena Mohanam, Sanjeeva |
author_facet | Bhaskara, Vasantha Kumar Mohanam, Indra Gujrati, Meena Mohanam, Sanjeeva |
author_sort | Bhaskara, Vasantha Kumar |
collection | PubMed |
description | BACKGROUND: Neuroblastoma is the most common extracranial pediatric solid tumor. Intermittent hypoxia, which is characterized by cyclic periods of hypoxia and reoxygenation, has been shown to positively modulate tumor development and thereby induce tumor growth, angiogenic processes, and metastasis. Bone is one of the target organs of metastasis in advanced neuroblastoma Neuroblastoma cells produce osteoclast-activating factors that increase bone resorption by the osteoclasts. The present study focuses on how intermittent hypoxia preconditioned SH-SY5Y neuroblastoma cells modulate osteoclastogenesis in RAW 264.7 cells compared with neuroblastoma cells grown at normoxic conditions. METHODS: We inhibited HIF-1α and HIF-2α in neuroblastoma SH-SY5Y cells by siRNA/shRNA approaches. Protein expression of HIF-1α, HIF-2α and MAPKs were investigated by western blotting. Expression of osteoclastogenic factors were determined by real-time RT-PCR. The influence of intermittent hypoxia and HIF-1α siRNA on migration of neuroblastoma cells and in vitro differentiation of RAW 264.7 cells were assessed. Intratibial injection was performed with SH-SY5Y stable luciferase-expressing cells and in vivo bioluminescence imaging was used in the analysis of tumor growth in bone. RESULTS: Upregulation of mRNAs of osteoclastogenic factors VEGF and RANKL was observed in intermittent hypoxia-exposed neuroblastoma cells. Conditioned medium from the intermittent hypoxia-exposed neuroblastoma cells was found to enhance osteoclastogenesis, up-regulate the mRNAs of osteoclast marker genes including TRAP, CaSR and cathepsin K and induce the activation of ERK, JNK, and p38 in RAW 264.7 cells. Intermittent hypoxia-exposed neuroblastoma cells showed an increased migratory pattern compared with the parental cells. A significant increase of tumor volume was found in animals that received the intermittent hypoxia-exposed cells intratibially compared with parental cells. CONCLUSIONS: Intermittent hypoxic exposure enhanced capabilities of neuroblastoma cells in induction of osteoclast differentiation in RAW 264.7 cells. Increased migration and intratibial tumor growth was observed in intermittent hypoxia-exposed neuroblastoma cells compared with parental cells. |
format | Online Article Text |
id | pubmed-4141796 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-41417962014-08-25 Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells Bhaskara, Vasantha Kumar Mohanam, Indra Gujrati, Meena Mohanam, Sanjeeva PLoS One Research Article BACKGROUND: Neuroblastoma is the most common extracranial pediatric solid tumor. Intermittent hypoxia, which is characterized by cyclic periods of hypoxia and reoxygenation, has been shown to positively modulate tumor development and thereby induce tumor growth, angiogenic processes, and metastasis. Bone is one of the target organs of metastasis in advanced neuroblastoma Neuroblastoma cells produce osteoclast-activating factors that increase bone resorption by the osteoclasts. The present study focuses on how intermittent hypoxia preconditioned SH-SY5Y neuroblastoma cells modulate osteoclastogenesis in RAW 264.7 cells compared with neuroblastoma cells grown at normoxic conditions. METHODS: We inhibited HIF-1α and HIF-2α in neuroblastoma SH-SY5Y cells by siRNA/shRNA approaches. Protein expression of HIF-1α, HIF-2α and MAPKs were investigated by western blotting. Expression of osteoclastogenic factors were determined by real-time RT-PCR. The influence of intermittent hypoxia and HIF-1α siRNA on migration of neuroblastoma cells and in vitro differentiation of RAW 264.7 cells were assessed. Intratibial injection was performed with SH-SY5Y stable luciferase-expressing cells and in vivo bioluminescence imaging was used in the analysis of tumor growth in bone. RESULTS: Upregulation of mRNAs of osteoclastogenic factors VEGF and RANKL was observed in intermittent hypoxia-exposed neuroblastoma cells. Conditioned medium from the intermittent hypoxia-exposed neuroblastoma cells was found to enhance osteoclastogenesis, up-regulate the mRNAs of osteoclast marker genes including TRAP, CaSR and cathepsin K and induce the activation of ERK, JNK, and p38 in RAW 264.7 cells. Intermittent hypoxia-exposed neuroblastoma cells showed an increased migratory pattern compared with the parental cells. A significant increase of tumor volume was found in animals that received the intermittent hypoxia-exposed cells intratibially compared with parental cells. CONCLUSIONS: Intermittent hypoxic exposure enhanced capabilities of neuroblastoma cells in induction of osteoclast differentiation in RAW 264.7 cells. Increased migration and intratibial tumor growth was observed in intermittent hypoxia-exposed neuroblastoma cells compared with parental cells. Public Library of Science 2014-08-22 /pmc/articles/PMC4141796/ /pubmed/25148040 http://dx.doi.org/10.1371/journal.pone.0105555 Text en © 2014 Bhaskara et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Bhaskara, Vasantha Kumar Mohanam, Indra Gujrati, Meena Mohanam, Sanjeeva Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells |
title | Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells |
title_full | Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells |
title_fullStr | Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells |
title_full_unstemmed | Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells |
title_short | Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells |
title_sort | intermittent hypoxia effect on osteoclastogenesis stimulated by neuroblastoma cells |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4141796/ https://www.ncbi.nlm.nih.gov/pubmed/25148040 http://dx.doi.org/10.1371/journal.pone.0105555 |
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