Cargando…

The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P

Since the α1-adrenergic antagonist prazosin (PRZ) was introduced into medicine as a treatment for hypertension and benign prostate hyperplasia, several studies have shown that PRZ induces apoptosis in various cell types and interferes with endocytotic trafficking. Because PRZ is also able to induce...

Descripción completa

Detalles Bibliográficos
Autores principales: Fuchs, Robert, Stracke, Anika, Ebner, Nadine, Zeller, Christian Wolfgang, Raninger, Anna Maria, Schittmayer, Matthias, Kueznik, Tatjana, Absenger-Novak, Markus, Birner-Gruenberger, Ruth
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671317/
https://www.ncbi.nlm.nih.gov/pubmed/26449523
http://dx.doi.org/10.1016/j.tox.2015.09.008
_version_ 1782404386091171840
author Fuchs, Robert
Stracke, Anika
Ebner, Nadine
Zeller, Christian Wolfgang
Raninger, Anna Maria
Schittmayer, Matthias
Kueznik, Tatjana
Absenger-Novak, Markus
Birner-Gruenberger, Ruth
author_facet Fuchs, Robert
Stracke, Anika
Ebner, Nadine
Zeller, Christian Wolfgang
Raninger, Anna Maria
Schittmayer, Matthias
Kueznik, Tatjana
Absenger-Novak, Markus
Birner-Gruenberger, Ruth
author_sort Fuchs, Robert
collection PubMed
description Since the α1-adrenergic antagonist prazosin (PRZ) was introduced into medicine as a treatment for hypertension and benign prostate hyperplasia, several studies have shown that PRZ induces apoptosis in various cell types and interferes with endocytotic trafficking. Because PRZ is also able to induce apoptosis in malignant cells, its cytotoxicity is a focus of interest in cancer research. Besides inducing apoptosis, PRZ was shown to serve as a substrate for an amine uptake mechanism originally discovered in neurones called transport-P. In line with our hypothesis that transport-P is an endocytotic mechanism also present in non-neuronal tissue and linked to the cytotoxicity of PRZ, we tested the uptake of QAPB, a fluorescent derivative of PRZ, in cancer cell lines in the presence of inhibitors of transport-P and endocytosis. Early endosomes and lysosomes were visualised by expression of RAB5-RFP and LAMP1-RFP, respectively; growth and viability of cells in the presence of PRZ and uptake inhibitors were also tested. Cancer cells showed co-localisation of QAPB with RAB5 and LAMP1 positive vesicles as well as tubulation of lysosomes. The uptake of QAPB was sensitive to transport-P inhibitors bafilomycin A1 (inhibits v-ATPase) and the antidepressant desipramine. Endocytosis inhibitors pitstop(®) 2 (general inhibitor of endocytosis), dynasore (dynamin inhibitor) and methyl-β-cyclodextrin (cholesterol chelator) inhibited the uptake of QAPB. Bafilomycin A1 and methyl-β-cyclodextrin but not desipramine were able to preserve growth and viability of cells in the presence of PRZ. In summary, we confirmed the hypothesis that the cellular uptake of QAPB/PRZ represents an endocytotic mechanism equivalent to transport-P. Endocytosis of QAPB/PRZ depends on a proton gradient, dynamin and cholesterol, and results in reorganisation of the LAMP1 positive endolysosomal system. Finally, the link seen between the cellular uptake of PRZ and cell death implies a still unknown pro-apoptotic membrane protein with affinity towards PRZ.
format Online
Article
Text
id pubmed-4671317
institution National Center for Biotechnology Information
language English
publishDate 2015
record_format MEDLINE/PubMed
spelling pubmed-46713172016-01-02 The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P Fuchs, Robert Stracke, Anika Ebner, Nadine Zeller, Christian Wolfgang Raninger, Anna Maria Schittmayer, Matthias Kueznik, Tatjana Absenger-Novak, Markus Birner-Gruenberger, Ruth Toxicology Article Since the α1-adrenergic antagonist prazosin (PRZ) was introduced into medicine as a treatment for hypertension and benign prostate hyperplasia, several studies have shown that PRZ induces apoptosis in various cell types and interferes with endocytotic trafficking. Because PRZ is also able to induce apoptosis in malignant cells, its cytotoxicity is a focus of interest in cancer research. Besides inducing apoptosis, PRZ was shown to serve as a substrate for an amine uptake mechanism originally discovered in neurones called transport-P. In line with our hypothesis that transport-P is an endocytotic mechanism also present in non-neuronal tissue and linked to the cytotoxicity of PRZ, we tested the uptake of QAPB, a fluorescent derivative of PRZ, in cancer cell lines in the presence of inhibitors of transport-P and endocytosis. Early endosomes and lysosomes were visualised by expression of RAB5-RFP and LAMP1-RFP, respectively; growth and viability of cells in the presence of PRZ and uptake inhibitors were also tested. Cancer cells showed co-localisation of QAPB with RAB5 and LAMP1 positive vesicles as well as tubulation of lysosomes. The uptake of QAPB was sensitive to transport-P inhibitors bafilomycin A1 (inhibits v-ATPase) and the antidepressant desipramine. Endocytosis inhibitors pitstop(®) 2 (general inhibitor of endocytosis), dynasore (dynamin inhibitor) and methyl-β-cyclodextrin (cholesterol chelator) inhibited the uptake of QAPB. Bafilomycin A1 and methyl-β-cyclodextrin but not desipramine were able to preserve growth and viability of cells in the presence of PRZ. In summary, we confirmed the hypothesis that the cellular uptake of QAPB/PRZ represents an endocytotic mechanism equivalent to transport-P. Endocytosis of QAPB/PRZ depends on a proton gradient, dynamin and cholesterol, and results in reorganisation of the LAMP1 positive endolysosomal system. Finally, the link seen between the cellular uptake of PRZ and cell death implies a still unknown pro-apoptotic membrane protein with affinity towards PRZ. 2015-10-09 2015-12-02 /pmc/articles/PMC4671317/ /pubmed/26449523 http://dx.doi.org/10.1016/j.tox.2015.09.008 Text en This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Article
Fuchs, Robert
Stracke, Anika
Ebner, Nadine
Zeller, Christian Wolfgang
Raninger, Anna Maria
Schittmayer, Matthias
Kueznik, Tatjana
Absenger-Novak, Markus
Birner-Gruenberger, Ruth
The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P
title The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P
title_full The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P
title_fullStr The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P
title_full_unstemmed The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P
title_short The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P
title_sort cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-p
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671317/
https://www.ncbi.nlm.nih.gov/pubmed/26449523
http://dx.doi.org/10.1016/j.tox.2015.09.008
work_keys_str_mv AT fuchsrobert thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT strackeanika thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT ebnernadine thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT zellerchristianwolfgang thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT raningerannamaria thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT schittmayermatthias thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT kuezniktatjana thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT absengernovakmarkus thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT birnergruenbergerruth thecytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT fuchsrobert cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT strackeanika cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT ebnernadine cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT zellerchristianwolfgang cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT raningerannamaria cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT schittmayermatthias cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT kuezniktatjana cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT absengernovakmarkus cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp
AT birnergruenbergerruth cytotoxicityofthea1adrenoceptorantagonistprazosinislinkedtoanendocytoticmechanismequivalenttotransportp