Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathway
Yuqi Wu,1 Xiaobing Liu,2 Zizhen Qin,1 Li Hu,1 Xiangwei Wang1 1Department of Urology, Carson International Cancer Center, Shenzhen University General Hospital & Shenzhen University Clinical Medical Academy Center, Shenzhen University, Shenzhen, People’s Republic of China; 2Departme...
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doaj-cece49425dc449cca22b299924cfc9762020-11-24T22:36:04ZengDove Medical PressOncoTargets and Therapy1178-69302018-09-01Volume 115621563040478Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathwayWu YLiu XQin ZHu LWang XYuqi Wu,1 Xiaobing Liu,2 Zizhen Qin,1 Li Hu,1 Xiangwei Wang1 1Department of Urology, Carson International Cancer Center, Shenzhen University General Hospital & Shenzhen University Clinical Medical Academy Center, Shenzhen University, Shenzhen, People’s Republic of China; 2Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, People’s Republic of China Background: Sonodynamic therapy (SDT) is an emerging tumor-inhibiting method that has gained attention in cancer therapy in the last several years. Although autophagy has been observed in SDT-treated cancer cells, its role and mechanism of action remain unclear. This study aimed to investigate the effects of low-frequency ultrasound on autophagy and drug-resistance of paclitaxel (PTX)-resistant PC-3 cells via the endoplasmic reticulum stress (ERs)-mediated PI3K/AT/mTOR signaling pathway. Methods: CCK-8 assay was conducted to select the appropriate exposure time for PTX-resistant PC-3 cells under low-frequency ultrasound. PTX-resistant PC-3 cells were divided into a control group, PTX group, ultrasound group, ultrasound + PTX group, ultrasound + PTX + autophagy-related gene 5 (Atg5) siRNA group, and ultrasound + 4-PBA (an ERs inhibitor) group. Autophagy was observed by transmission electron microscopy (TEM) and fluorescence microscopy. Cell proliferation was evaluated using CCK-8 assay; apoptosis was detected by flow cytometry. Expression of multiple drug-resistance genes was detected by qRT-PCR. Western blotting was used to detect the expression of ERS-related proteins, autophagy-related proteins, apoptosis-related proteins, and PI3K/AKT/mTOR pathway-related proteins. Results: Ten-second exposure was selected as optimal for all experiments. Compared to the PTX group, the level of autophagy, inhibition rate, apoptosis rate, and expression of ERS-related proteins (GRP78) increased, whereas the expression of multiple drug-resistance genes (MRP3, MRP7, and P-glycoprotein), PI3K/AKT/mTOR pathway-related proteins (PI3K, p-AKT, mTORC1), and apoptosis-related proteins (Bcl-2, NF-κB) decreased in PTX-resistant PC-3 cells after low-frequency ultrasound and PTX treatment for 24 h. These trends were more obvious after treatment with Atg5 siRNA, excluding the autophagy level. Post 4-PBA-treatment, the expression of GRP78 and LC3II proteins decreased, whereas that of PI3K, p-AKT, and mTORC1 increased. Conclusion: Results indicated that ultrasound induces autophagy by ERs-mediated PI3K/AKT/mTOR signaling pathway in PTX-resistant PC-3 cells; this autophagy acts as a cytoprotector during low-frequency ultrasound-mediated reversal of drug resistance. Keywords: prostate cancer, multidrug resistance, sonodynamic therapy, autophagy, apoptosis, endoplasmic reticulum stresshttps://www.dovepress.com/low-frequency-ultrasound-enhances-chemotherapy-sensitivity-and-induces-peer-reviewed-article-OTTAutophagyMultidrug resistanceSonodynamic therapyEndoplasmic reticulum stressapoptosis |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Wu Y Liu X Qin Z Hu L Wang X |
spellingShingle |
Wu Y Liu X Qin Z Hu L Wang X Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathway OncoTargets and Therapy Autophagy Multidrug resistance Sonodynamic therapy Endoplasmic reticulum stress apoptosis |
author_facet |
Wu Y Liu X Qin Z Hu L Wang X |
author_sort |
Wu Y |
title |
Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathway |
title_short |
Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathway |
title_full |
Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathway |
title_fullStr |
Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathway |
title_full_unstemmed |
Low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in PTX-resistant PC-3 cells via the endoplasmic reticulum stress-mediated PI3K/Akt/mTOR signaling pathway |
title_sort |
low-frequency ultrasound enhances chemotherapy sensitivity and induces autophagy in ptx-resistant pc-3 cells via the endoplasmic reticulum stress-mediated pi3k/akt/mtor signaling pathway |
publisher |
Dove Medical Press |
series |
OncoTargets and Therapy |
issn |
1178-6930 |
publishDate |
2018-09-01 |
description |
Yuqi Wu,1 Xiaobing Liu,2 Zizhen Qin,1 Li Hu,1 Xiangwei Wang1 1Department of Urology, Carson International Cancer Center, Shenzhen University General Hospital & Shenzhen University Clinical Medical Academy Center, Shenzhen University, Shenzhen, People’s Republic of China; 2Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, People’s Republic of China Background: Sonodynamic therapy (SDT) is an emerging tumor-inhibiting method that has gained attention in cancer therapy in the last several years. Although autophagy has been observed in SDT-treated cancer cells, its role and mechanism of action remain unclear. This study aimed to investigate the effects of low-frequency ultrasound on autophagy and drug-resistance of paclitaxel (PTX)-resistant PC-3 cells via the endoplasmic reticulum stress (ERs)-mediated PI3K/AT/mTOR signaling pathway. Methods: CCK-8 assay was conducted to select the appropriate exposure time for PTX-resistant PC-3 cells under low-frequency ultrasound. PTX-resistant PC-3 cells were divided into a control group, PTX group, ultrasound group, ultrasound + PTX group, ultrasound + PTX + autophagy-related gene 5 (Atg5) siRNA group, and ultrasound + 4-PBA (an ERs inhibitor) group. Autophagy was observed by transmission electron microscopy (TEM) and fluorescence microscopy. Cell proliferation was evaluated using CCK-8 assay; apoptosis was detected by flow cytometry. Expression of multiple drug-resistance genes was detected by qRT-PCR. Western blotting was used to detect the expression of ERS-related proteins, autophagy-related proteins, apoptosis-related proteins, and PI3K/AKT/mTOR pathway-related proteins. Results: Ten-second exposure was selected as optimal for all experiments. Compared to the PTX group, the level of autophagy, inhibition rate, apoptosis rate, and expression of ERS-related proteins (GRP78) increased, whereas the expression of multiple drug-resistance genes (MRP3, MRP7, and P-glycoprotein), PI3K/AKT/mTOR pathway-related proteins (PI3K, p-AKT, mTORC1), and apoptosis-related proteins (Bcl-2, NF-κB) decreased in PTX-resistant PC-3 cells after low-frequency ultrasound and PTX treatment for 24 h. These trends were more obvious after treatment with Atg5 siRNA, excluding the autophagy level. Post 4-PBA-treatment, the expression of GRP78 and LC3II proteins decreased, whereas that of PI3K, p-AKT, and mTORC1 increased. Conclusion: Results indicated that ultrasound induces autophagy by ERs-mediated PI3K/AKT/mTOR signaling pathway in PTX-resistant PC-3 cells; this autophagy acts as a cytoprotector during low-frequency ultrasound-mediated reversal of drug resistance. Keywords: prostate cancer, multidrug resistance, sonodynamic therapy, autophagy, apoptosis, endoplasmic reticulum stress |
topic |
Autophagy Multidrug resistance Sonodynamic therapy Endoplasmic reticulum stress apoptosis |
url |
https://www.dovepress.com/low-frequency-ultrasound-enhances-chemotherapy-sensitivity-and-induces-peer-reviewed-article-OTT |
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