1
|
Waseem M, Gujrati H, Wang BD. Tumor suppressive miR-99b-5p as an epigenomic regulator mediating mTOR/AR/SMARCD1 signaling axis in aggressive prostate cancer. Front Oncol 2023; 13:1184186. [PMID: 38023145 PMCID: PMC10661933 DOI: 10.3389/fonc.2023.1184186] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction African American (AA) men exhibited 2.3-fold higher PCa incidence and 1.7-fold higher PCa mortality rates when compared to the European American (EA) men. Besides the socioeconomic factors, emerging evidence has highlighted that biological risk factors may play critical roles in the AA PCa disparities. Previously, we have shown that downregulated miR-99b-5p and upregulated mTOR cooperatively promotes the AA PCa aggressiveness and drug resistance. Methods In this study, we aimed to explore the miR-99b-5p/mTOR/AR/SMARCD1 signaling axis in AA PCa aggressiveness. The analyses used in the study included immunofluorescence, western blot, in-vitro functional assays (TUNEL, colony forming, and MTT), and chromatin immunoprecipitation (ChIP)-qPCR assays in 2D and/or 3D culture model of EA PCa and AA PCa cell lines. Results Specifically, the immunofluorescence staining, and western blot analysis has revealed that nuclear mTOR, AR, and SMARCD1 were highly expressed in AA PCa (MDA PCa 2b) compared to EA PCa (LNCaP) cell line. Western blot analysis further revealed that miR-99b-5p inhibited protein levels of mTOR, AR/AR-V7 and SMARCD1 in cytoplasm and nuclei of EA and AA PCa. The in-vitro functional (MTT, TUNEL, and clonogenic) assays have demonstrated that miR-99b-5p effectively inhibited cell proliferation/survival and induced cell apoptosis in EA and AA PCa cells. Moreover, combination of miR-99b-5p and enzalutamide (Enz) synergistically enhances the cytotoxicity against aggressive AA PCa and castration-resistant prostate cancer (CRPC). mTOR ChIP-qPCR assays further demonstrated that miR-99b-5p or miR-99b-5p/Enz significantly reduces the recruitment of mTOR to the genes involved in the metabolic reprogramming in CRPC. Discussion Taken together, miR-99b-5p may function as an epigenomic driver to modulate the mTOR/AR/SMARCD1 signaling axis in AA PCa and resistant CRPC.
Collapse
Affiliation(s)
- Mohammad Waseem
- Department of Pharmaceutical Sciences, University of Maryland Eastern Shore School of Pharmacy and Health Professions, Princess Anne, MD, United States
| | - Himali Gujrati
- Department of Pharmaceutical Sciences, University of Maryland Eastern Shore School of Pharmacy and Health Professions, Princess Anne, MD, United States
| | - Bi-Dar Wang
- Department of Pharmaceutical Sciences, University of Maryland Eastern Shore School of Pharmacy and Health Professions, Princess Anne, MD, United States
- Hormone Related Cancers Program, University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, United States
| |
Collapse
|
2
|
Hata J, Harigane Y, Matsuoka K, Akaihata H, Yaginuma K, Meguro S, Hoshi S, Sato Y, Ogawa S, Uemura M, Kojima Y. Mechanism of Androgen-Independent Stromal Proliferation in Benign Prostatic Hyperplasia. Int J Mol Sci 2023; 24:11634. [PMID: 37511400 PMCID: PMC10380833 DOI: 10.3390/ijms241411634] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023] Open
Abstract
Benign prostatic hyperplasia (BPH) is a chronic proliferative disease showing stromal-dominant proliferation. However, the detailed proliferation mechanism has remained unclear. Although aging and androgen have been reported as definitive risk factors for BPH, recent studies have focused on the involvement of androgen-independent factors. Androgen-independent factors include ischemia, oxidative stress, metabolic syndrome, infection, autoimmune reactions, and inflammation, with inflammation in BPH tissues playing a central role in the BPH proliferative process. Inflammation in BPH tissues by various factors finally leads to tissue remodeling and stromal proliferation through the wound healing process of the prostate. To elucidate the proliferative mechanism of BPH, a study using whole-genome gene expression analysis in a stromal-dominant BPH rat model was performed and showed that immune response-related pathways and complement classical pathways are activated. Furthermore, expression analysis using this BPH rat model showed that the autoimmune reaction triggered complement pathway activation in the proliferative process of BPH. BPH is a multifactorial disease, and understanding the role of androgen-independent factors including immune responses contributes to elucidating the pathogenesis of BPH. Androgen-independent factors may lead to new therapeutic targets for BPH, and further development of this research is expected.
Collapse
Affiliation(s)
- Junya Hata
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Yuki Harigane
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Kanako Matsuoka
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Hidenori Akaihata
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Kei Yaginuma
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Satoru Meguro
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Seiji Hoshi
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Yuichi Sato
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Soichiro Ogawa
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Motohide Uemura
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| | - Yoshiyuki Kojima
- Department of Urology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima 9601295, Japan
| |
Collapse
|
3
|
Assoun EN, Meyer AN, Jiang MY, Baird SM, Haas M, Donoghue DJ. Characterization of iPS87, a prostate cancer stem cell-like cell line. Oncotarget 2020; 11:1075-1084. [PMID: 32256979 PMCID: PMC7105161 DOI: 10.18632/oncotarget.27524] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/03/2020] [Indexed: 12/31/2022] Open
Abstract
Prostate cancer affects hundreds of thousands of men and families throughout the world. Although chemotherapy, radiation, surgery, and androgen deprivation therapy are applied, these therapies do not cure metastatic prostate cancer. Patients treated by androgen deprivation often develop castration resistant prostate cancer which is incurable. Novel approaches of treatment are clearly necessary. We have previously shown that prostate cancer originates as a stem cell disease. A prostate cancer patient sample, #87, obtained from prostatectomy surgery, was collected and frozen as single cell suspension. Cancer stem cell cultures were grown, single cell-cloned, and shown to be tumorigenic in SCID mice. However, outside its natural niche, the cultured prostate cancer stem cells lost their tumor-inducing capability and stem cell marker expression after approximately 8 transfers at a 1:3 split ratio. Tumor-inducing activity could be restored by inducing the cells to pluripotency using the method of Yamanaka. Cultures of human prostate-derived normal epithelial cells acquired from commercial sources were similarly induced to pluripotency and these did not acquire a tumor phenotype in vivo. To characterize the iPS87 cell line, cells were stained with antibodies to various markers of stem cells including: ALDH7A1, LGR5, Oct4, Nanog, Sox2, Androgen Receptor, and Retinoid X Receptor. These markers were found to be expressed by iPS87 cells, and the high tumorigenicity in SCID mice of iPS87 was confirmed by histopathology. This research thus characterizes the iPS87 cell line as a cancer-inducing, stem cell-like cell line, which can be used in the development of novel treatments for prostate cancer.
Collapse
Affiliation(s)
- Erika N. Assoun
- Division of Biological Sciences, University of California San Diego, La Jolla, San Diego, CA 92093, USA
| | - April N. Meyer
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, San Diego, CA 92093, USA
| | - Maggie Y. Jiang
- Division of Biological Sciences, University of California San Diego, La Jolla, San Diego, CA 92093, USA
| | - Stephen M. Baird
- Department of Pathology, University of California San Diego, La Jolla, San Diego, CA 92093, USA
| | - Martin Haas
- Moores UCSD Cancer Center, University of California San Diego, La Jolla, San Diego, CA 92093, USA
| | - Daniel J. Donoghue
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, San Diego, CA 92093, USA
- Moores UCSD Cancer Center, University of California San Diego, La Jolla, San Diego, CA 92093, USA
| |
Collapse
|
4
|
Peng R, Li Z, Lin Z, Wang Y, Wang W, Hu B, Wang X, Zhang J, Wang Y, Zhou R, Lu C, Shen Y, Wang J, Shi G. The HSP90 inhibitor 17-PAG effectively inhibits the proliferation and migration of androgen-independent prostate cancer cells. Am J Cancer Res 2015; 5:3198-3209. [PMID: 26693070 PMCID: PMC4656741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/08/2015] [Indexed: 06/05/2023] Open
Abstract
Castration-resistant prostate cancer (CRPC) ultimately occurs after a period of treatment with androgen deprivation therapy. Furthermore, CRPC patients can only derive limited survival benefits from traditional cytotoxic drugs. HSP90, which is a molecular chaperone, plays a vital role in client protein processing and maintaining the function of cells. HSP90 is usually overexpressed in prostate cancer tissues, which makes it a potential target for managing prostate cancer. Geldanamycin (GA), which was recognized as the first natural HSP90 inhibitor, has demonstrated potent anti-tumor efficacy in large-scale pre-clinical studies, but its application in the clinic is not permitted due to its liver toxicity and unstable physical properties. In this study, we report a new GA derivative, 17-PAG (17-(propynylamino)-17-demethoxygeldanamycin), which demonstrates highly effective anti-tumor activity against androgen-independent prostate cancer cells. Treating cells with 17-PAG dose-dependently suppressed proliferation, reduced colony formation and induced apoptosis of DU-145/C4-2B cells. Moreover, 17-PAG suppressed the migration and invasion of DU-145/C4-2B cells by regulating epithelial mesenchymal transition (EMT). 17-PAG also downregulated the HSP90 client proteins, including Her2, EGFR, C-Raf, AKT, p-AKT, and CDK4. Animal assays confirmed that 17-PAG shows strong anti-tumor effects with no obvious organ toxicity in DU-145 cell xenografted nude mice. These results provide us with a potential target for treating androgen-independent prostate cancer in a safe and effective manner.
Collapse
Affiliation(s)
- Ruixian Peng
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Zhenyu Li
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong UniversityNo. 44 West Wenhua Road, Jinan 250012, Shandong, P. R. China
| | - Zhiyuan Lin
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Yang Wang
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Wei Wang
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Bo Hu
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Xilong Wang
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Jun Zhang
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Yangyun Wang
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Renyuan Zhou
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Chunhua Lu
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong UniversityNo. 44 West Wenhua Road, Jinan 250012, Shandong, P. R. China
| | - Yuemao Shen
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong UniversityNo. 44 West Wenhua Road, Jinan 250012, Shandong, P. R. China
| | - Jifeng Wang
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| | - Guowei Shi
- Department of Urology, The Fifth People’s Hospital of Shanghai, Fudan UniversityShanghai 200240, P. R. China
- Urology Research Center, Fudan UniversityShanghai 200240, P. R. China
| |
Collapse
|
5
|
Hensel JA, Chanda D, Kumar S, Sawant A, Grizzle WE, Siegal GP, Ponnazhagan S. LL-37 as a therapeutic target for late stage prostate cancer. Prostate 2011; 71:659-70. [PMID: 20957672 PMCID: PMC3025071 DOI: 10.1002/pros.21282] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 08/31/2010] [Indexed: 11/12/2022]
Abstract
BACKGROUND The antimicrobial peptide, leucine-leucine-37 (LL-37), stimulates proliferation, angiogenesis, and cellular migration, inhibits apoptosis and is associated with inflammation. Since these functional processes are often exaggerated in cancer, the aim of the present study was to investigate the expression and role of LL-37 in prostate cancer (PCa) and establish its value as a therapeutic target. METHODS We evaluated the expression of LL-37 and the murine orthologue, cathelicidin-related antimicrobial peptide (CRAMP) in human and murine prostate tumors, respectively. Compared to normal/benign prostate tissue, both LL-37 and CRAMP were increasingly over-expressed with advancing grades of primary PCa and its metastasis in human tissues and in the transgenic adenocarcinoma mouse prostate (TRAMP) model, correspondingly. We subsequently knocked-down CRAMP in the highly tumorigenic TRAMP-C1 cell line via a RNA interference strategy to examine the importance of CRAMP on cellular proliferation, angiogenesis, invasion, apoptosis, activation of signaling pathways and tumor kinetics. RESULTS Abrogation of CRAMP expression led to decreased proliferation, invasion, type IV collagenase, and the amount of phosphorylated Erk1/2 and Akt signaling in vitro. These results were paralleled in vivo. Syngenic implantation of TRAMP-C1 cells subjected to CRAMP knock-down resulted in a decreased tumor incidence and size, and the down-regulation of pro-tumorigenic mechanisms. CONCLUSIONS CRAMP knock-down in a murine PCa model analogously demonstrated the tumorigenic contributions of LL-37 in PCa and its potential as a novel therapeutic target for the treatment of PCa and potentially, other cancers over-expressing the peptide.
Collapse
MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Adenocarcinoma/pathology
- Animals
- Antimicrobial Cationic Peptides/biosynthesis
- Antimicrobial Cationic Peptides/metabolism
- Cathelicidins/biosynthesis
- Cathelicidins/deficiency
- Cathelicidins/genetics
- Cathelicidins/metabolism
- Cell Growth Processes/physiology
- Cell Line, Tumor
- Gene Knockdown Techniques
- Humans
- Immunohistochemistry
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Molecular Targeted Therapy/methods
- Neoplasms, Hormone-Dependent/genetics
- Neoplasms, Hormone-Dependent/metabolism
- Neoplasms, Hormone-Dependent/pathology
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/pathology
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/pathology
- RNA Interference
- RNA, Neoplasm/chemistry
- RNA, Neoplasm/genetics
- Reverse Transcriptase Polymerase Chain Reaction
Collapse
Affiliation(s)
| | | | | | | | | | | | - Selvarangan Ponnazhagan
- Corresponding author, Selvarangan Ponnazhagan, Ph.D., Department of Pathology, 701 19 Street South, LHRB 513, The University of Alabama at Birmingham, Birmingham, AL 35294-0007, Phone: (205) 934-6731; Fax: (205) 975-9927,
| |
Collapse
|
6
|
Jin RJ, Lho Y, Connelly L, Wang Y, Yu X, Jean LS, Case TC, Ellwood-Yen K, Sawyers CL, Bhowmick NA, Blackwell TS, Yull FE, Matusik RJ. The nuclear factor-kappaB pathway controls the progression of prostate cancer to androgen-independent growth. Cancer Res 2008; 68:6762-9. [PMID: 18701501 PMCID: PMC2840631 DOI: 10.1158/0008-5472.can-08-0107] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Typically, the initial response of a prostate cancer patient to androgen ablation therapy is regression of the disease. However, the tumor will progress to an "androgen-independent" stage that results in renewed growth and spread of the cancer. Both nuclear factor-kappaB (NF-kappaB) expression and neuroendocrine differentiation predict poor prognosis, but their precise contribution to prostate cancer progression is unknown. This report shows that secretory proteins from neuroendocrine cells will activate the NF-kappaB pathway in LNCaP cells, resulting in increased levels of active androgen receptor (AR). By blocking NF-kappaB signaling in vitro, AR activation is inhibited. In addition, the continuous activation of NF-kappaB signaling in vivo by the absence of the IkappaBalpha inhibitor prevents regression of the prostate after castration by sustaining high levels of nuclear AR and maintaining differentiated function and continued proliferation of the epithelium. Furthermore, the NF-kappaB pathway was activated in the ARR(2)PB-myc-PAI (Hi-myc) mouse prostate by cross-breeding into a IkappaBalpha(+/-) haploid insufficient line. After castration, the mouse prostate cancer continued to proliferate. These results indicate that activation of NF-kappaB is sufficient to maintain androgen-independent growth of prostate and prostate cancer by regulating AR action. Thus, the NF-kappaB pathway may be a potential target for therapy against androgen-independent prostate cancer.
Collapse
MESH Headings
- Androgens/pharmacology
- Animals
- Apoptosis
- Blotting, Western
- Carcinoma, Neuroendocrine/pathology
- Castration
- Cell Nucleus/metabolism
- Disease Progression
- Gene Expression Regulation, Neoplastic
- Humans
- I-kappa B Kinase/physiology
- Male
- Mice
- Mice, Knockout
- NF-kappa B/genetics
- NF-kappa B/metabolism
- Neoplasms, Hormone-Dependent/genetics
- Neoplasms, Hormone-Dependent/metabolism
- Neoplasms, Hormone-Dependent/pathology
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/pathology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Transcription, Genetic
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- Ren Jie Jin
- Vanderbilt Prostate Cancer Center and Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Yongsoo Lho
- Department of Urology, Konkuk University Hospital, Seoul, 143-729 Korea
| | - Linda Connelly
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Yongqing Wang
- Vanderbilt Prostate Cancer Center and Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Xiuping Yu
- Vanderbilt Prostate Cancer Center and Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Leshana Saint Jean
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Thomas C. Case
- Vanderbilt Prostate Cancer Center and Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Katharine Ellwood-Yen
- Departments of Medicine, Urology, Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA
| | - Charles L. Sawyers
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Neil A. Bhowmick
- Vanderbilt Prostate Cancer Center and Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Timothy S. Blackwell
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Departments of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Fiona E. Yull
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert J. Matusik
- Vanderbilt Prostate Cancer Center and Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| |
Collapse
|
7
|
Benbrahim-Tallaa L, Webber MM, Waalkes MP. Acquisition of androgen independence by human prostate epithelial cells during arsenic-induced malignant transformation. Environ Health Perspect 2005; 113:1134-9. [PMID: 16140617 PMCID: PMC1280391 DOI: 10.1289/ehp.7832] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Lethal phenotypes of human prostate cancer are characterized by progression to androgen independence, although the mechanisms behind this progression remain unclear. Arsenic is a potential human prostate carcinogen that may affect tumor progression. In this study, we used a prostate cancer cell model in which an immortalized, nontumorigenic human prostate epithelial cell line (RWPE-1) had been malignantly transformed by chronic low-level arsenic to help determine whether arsenic affects prostate tumor progression. Control and CAsE-PE (chronic-arsenic-exposed human prostate epithelial) cells were continuously maintained in a complete medium [keratinocyte serum-free medium (K-SFM) with bovine pituitary extract and epidermal growth factor] or in a steroid-depleted medium (K-SFM alone). The arsenic-transformed cells showed a more rapid proliferation rate in complete medium than did control cells and also showed sustained proliferation in steroid-reduced medium. Although both control and CAsE-PE cells showed similar levels of androgen receptor (AR), androgens were less effective in stimulating cell proliferation and AR-related gene expression in CAsE-PE cells. For instance, dihydrotestosterone caused a 4.5-fold increase in prostate-specific antigen transcript in control cells but only a 1.5-fold increase in CAsE-PE cells. CAsE-PE cells also showed relatively low levels of growth stimulation by nonandrogen steroids, such as estradiol. Thus, arsenic-induced malignant transformation is associated with acquired androgen independence in human prostate cells. This acquired androgen independence was apparently not due to AR up-regulation, increased activity, or altered ligand specificity. The precise manner in which arsenic altered CAsE-PE growth and progression is undefined but may involve a bypass of AR involving direct stimulation of downstream signaling pathways.
Collapse
Affiliation(s)
- Lamia Benbrahim-Tallaa
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | | | | |
Collapse
|