Ashkan Mortezavi1, Souzan Salemi1, Benedikt Kranzbühler1, Oliver Gross1, Tullio Sulser1, Hans-Uwe Simon2, Daniel Eberli3. 1. Laboratory for Tissue Engineering and Stem Cell Therapy, Department of Urology, University Hospital Zürich, Frauenklinikstrasse 10, 8091, Zurich, Switzerland. 2. Institute of Pharmacology, University of Bern, Inselspital, INO-F, 3010, Bern, Switzerland. 3. Laboratory for Tissue Engineering and Stem Cell Therapy, Department of Urology, University Hospital Zürich, Frauenklinikstrasse 10, 8091, Zurich, Switzerland. daniel.eberli@usz.ch.
Abstract
PURPOSE: Abiraterone acetate (AA) plus prednisone is an approved treatment of advanced prostate cancer (PCa). Autophagy is linked to drug resistance in numerous types of cancers. We hypothesized, that upregulation of autophagy is one of the mechanisms by which PCa cells survive AA anti-tumor treatment and therefore evaluated the potential effect of a combination with autophagy inhibition. METHODS: Human PCa LNCaP cell lines were cultured in steroid-free medium and treated with AA. Autophagy was inhibited by 3-methyladenine, chloroquine and ATG5 siRNA knock-down. Cell viability and apoptosis was assessed by flow cytometry and fluorescence microscopy, and autophagy was monitored by immunohistochemistry, AUTOdot and Western blotting. RESULTS: Western blot revealed upregulation of ATG5 and LC3 II with a reduction of p62 protein expression in AA-treated cells, indicating upregulation of autophagy. These data were supported by results obtained with immunocytochemistry and AUTOdot assays. Using flow cytometry, we showed that combining AA with autophagy inhibition significantly impaired cell viability (1.3-1.6-fold, p < 0.001) and increased apoptosis (1.4-1.5-fold, p < 0.001) compared to AA treatment alone. CONCLUSIONS: AA activates autophagy as a cytoprotective mechanism in LNCaP prostate cancer cells and targeting of autophagy enhances the antitumor effect of the compound.
PURPOSE:Abiraterone acetate (AA) plus prednisone is an approved treatment of advanced prostate cancer (PCa). Autophagy is linked to drug resistance in numerous types of cancers. We hypothesized, that upregulation of autophagy is one of the mechanisms by which PCa cells survive AA anti-tumor treatment and therefore evaluated the potential effect of a combination with autophagy inhibition. METHODS:Human PCa LNCaP cell lines were cultured in steroid-free medium and treated with AA. Autophagy was inhibited by 3-methyladenine, chloroquine and ATG5 siRNA knock-down. Cell viability and apoptosis was assessed by flow cytometry and fluorescence microscopy, and autophagy was monitored by immunohistochemistry, AUTOdot and Western blotting. RESULTS: Western blot revealed upregulation of ATG5 and LC3 II with a reduction of p62 protein expression in AA-treated cells, indicating upregulation of autophagy. These data were supported by results obtained with immunocytochemistry and AUTOdot assays. Using flow cytometry, we showed that combining AA with autophagy inhibition significantly impaired cell viability (1.3-1.6-fold, p < 0.001) and increased apoptosis (1.4-1.5-fold, p < 0.001) compared to AA treatment alone. CONCLUSIONS: AA activates autophagy as a cytoprotective mechanism in LNCaP prostate cancer cells and targeting of autophagy enhances the antitumor effect of the compound.
Authors: Chenchu Lin; Alicia M Blessing; Thomas L Pulliam; Yan Shi; Sandi R Wilkenfeld; Jenny J Han; Mollianne M Murray; Alexander H Pham; Kevin Duong; Sonja N Brun; Reuben J Shaw; Michael M Ittmann; Daniel E Frigo Journal: Oncogene Date: 2021-02-02 Impact factor: 9.867
Authors: Milad Ashrafizadeh; Mahshid Deldar Abad Paskeh; Sepideh Mirzaei; Mohammad Hossein Gholami; Ali Zarrabi; Farid Hashemi; Kiavash Hushmandi; Mehrdad Hashemi; Noushin Nabavi; Francesco Crea; Jun Ren; Daniel J Klionsky; Alan Prem Kumar; Yuzhuo Wang Journal: J Exp Clin Cancer Res Date: 2022-03-22