Atorvastatin induces autophagic cell death in prostate cancer cells in vitro

Abstract

Abstract. Athough it is well known that apoptosis contributes to cancer cell death, the role of autophagy in cancer cell death has remained in dispute. Atorvastatin has been suggested to exhibit anti-cancer effects. The present study aimed to examine atorvastatin-induced autophagy-associated cell death and the autophagy-associated gene expression profile in the PC3 prostate carcinoma cell line. The atorvastatin-induced process of autophagy in PC3 cells was determined via evaluation of the cellular expression levels of autophagosomal marker light-chain-3 (LC3)-II, using immunoblotting and counting of green fluorescent protein (GFP)-LC3-transfected autophagic cells. Apoptosis was examined by terminal deoxynucleotidyl transferase dUTP nick end labeling assay and an MTT assay was used to evaluate cell viability. Total RNA of PC3 cells was isolated for characterization of the gene expression profile following atorvastatin treatment. Atorvastatin treatment of PC3 cells for 24 h increased the expression of green fluorescent protein-LC3-II by >25%, and expression continued for >72 h, while apoptosis was not significantly induced within this time period. Four genes associated with the autophagy machinery were also significantly upregulated. In the presence of atorvastatin, autophagy may be unable to abrogate cell damage and may therefore contribute to cellular dysfunction, leading to autophagic/type II programmed cell death. In response to atorvastatin treatment, the expression of genes involved in autophagic mediating pathways may have a role in tumor suppression. IntroductionProstate cancer is the most frequently diagnosed non-cutaneous malignancy and the second leading cause of death due to cancer amongst males worldwide (1). Treatment options for localized disease include watchful waiting, surgery and radiotherapy (2). However, in terms of a definitive treatment, despite developments in systemic chemotherapy strategies, minimal improvements in the quality of life and overall survival have been achieved amongst patients with prostate cancer (3). The development of novel treatment strategies for patients with advanced metastatic prostate cancers remains a challenge.The PC3 human prostate cancer cell line [p53-and phosphatase and tensin homolog (PTEN)-] was established from a prostatic adenocarcinoma, which was metastatic to bone. It has been extensively used as a cell model for the study of prostate cancer and is generally assumed to model an advanced stage of prostate cancer (4). PC3 cells are resistant to numerous chemotherapy drugs and apoptosis inducers (5,6).At o r va s t a t i n, a 3 -hyd r ox y-3 -m e t hylg lu t a r yl (HMG)-coenzyme A reductase inhibitor, is among the widely prescribed drugs used to lower cholesterol and prevent cardiovascular diseases (7). In addition to its cholesterol-lowering effect, atorvastatin has pro-apoptotic and anti-metastatic effects on prostate cancer cells (8,9). Parikh et al (10) hypothesized that atorvastatin may induce autophagy-associated cell death in PC3 cells. However, the...

Evaluation of the Cytotoxic and Autophagic Effects of Atorvastatin on MCF-7 Breast Cancer Cells

“…Breast cancer cells showed Beclin-1 and LC3B immunoreactivity and widened perinuclear cisterna, induced by stress depending atorvastatin treatment. Increased vacuolization and engulfment of membrane residues and/or cytoplasm by autophagic vesicles may be attributed to autophagy, and these changes were more prominently observed in MCF-7 cells treated with 10 and 20 μM atorvastatin for 48 h. Our results confirm previous studies that showed autophagic effects of atorvastatin on different kinds of cancer cell lines ( 10 , 11 , 12 , 13 , 14 ). Atorvastatin induced autophagic alterations in MCF-7 cells even at the lowest doses used.…”

“…Autophagy is a type of cell death process by which cells recycle their unessential organelles and components under stress conditions ( 9 ). It provides new insight into cell death pathways, especially in cancer where it is thought to have a dual role ( 10 , 11 , 12 , 13 ). Thus, autophagy may behave both as a tumor suppressor by preventing accumulation of damaged organelles and misfolded proteins or as a cell survival mechanism by promoting the development of tumors ( 12 ).…”

“…Therefore, understanding the role of autophagy and its regulation in cancer cells may be essential to develop new cancer drugs. Although atorvastatin has been reported to have some autophagic effects on different kinds of cancer cell lines, there is no evidence in breast cancer ( 10 , 14 ). Our article on autophagy examined the anti-proliferative effects of atorvastatin on breast cancer MCF-7 cells.…”

Rottlerin-induced autophagy leads to apoptosis in bladder cancer cells

“…The majority of studies have indicated that autophagy inhibition sensitizes tumor cells to a wide spectrum of cancer therapies, while others have shown that treatment-induced tumor cell death requires intact autophagic machinery (27–32). For instance, atorvastatin is considered by some to cause autophagy to promote apoptosis in human prostate cancer cells (33), whilst others have a contrasting views, and consider that inhibition of autophagy potentiates atorvastatin-induced apoptotic cell death (34). Although there is known crosstalk between autophagy and apoptosis, since they share certain signaling pathways and proteins, the mechanism where this bridging occurs has not been fully defined (35).…”

Atorvastatin attenuates testosterone‐induced benign prostatic hyperplasia in rats: role of peroxisome proliferator‐activated receptor‐γ and cyclo‐oxygenase‐2

“…Epidemiological survey indicated that use of statin drugs is linked to reduction in the risk of advanced prostate cancer . Atorvastatin (3‐hydroxy‐3‐methylglutaryl‐CoA (HMG‐CoA) reductase inhibitor), widely used for the prevention and treatment of hypercholesterolemia, has been shown to inhibit the proliferation and induce apoptosis of prostate cancer cells in vitro . Moreover, inflammation has been linked with the development and progression of BPH , and the presence of intraprostatic inflammatory infiltrations in BPH tissues such as IL‐17, COX‐1, and COX‐2 has been reported .…”