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Moreira D, Zhang Q, Hossain DMS, Nechaev S, Li H, Kowolik CM, D'Apuzzo M, Forman S, Jones J, Pal SK, Kortylewski M. TLR9 signaling through NF-κB/RELA and STAT3 promotes tumor-propagating potential of prostate cancer cells. Oncotarget 2016; 6:17302-13. [PMID: 26046794 PMCID: PMC4627309 DOI: 10.18632/oncotarget.4029] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 05/09/2015] [Indexed: 12/16/2022] Open
Abstract
Prostate cancer progression was associated with tumorigenic signaling activated by proinflammatory mediators. However, the etiology of these events remains elusive. Here, we demonstrate that triggering of the innate immune receptor, Toll-like Receptor 9 (TLR9), in androgen-independent prostate cancer cells initiates signaling cascade leading to increased tumor growth and progression. Using limited dilution/serial transplantation experiments, we show that TLR9 is essential for prostate cancer cells' potential to propagate and self-renew in vivo. Furthermore, low expression or silencing of TLR9 limits the clonogenic potential and mesenchymal stem cell-like properties of LNCaP- and PC3-derived prostate cancer cell variants. Genome-wide transcriptional analysis of prostate cancer cells isolated from xenotransplanted TLR9-positive and -negative tumors revealed a unique gene expression signature, with prominent upregulation of inflammation- and stem cell-related markers. TLR9 signaling orchestrated expression of critical stem cell-related genes such as NKX3.1, KLF-4, BMI-1 and COL1A1, at both mRNA and protein levels. Our further analysis identified that TLR9-induced NF-κB/RELA and STAT3 transcription factors co-regulated NKX3.1 and KLF4 gene expression by directly binding to both promoters. Finally, we demonstrated the feasibility of using TLR9-targeted siRNA delivery to block RELA- and STAT3-dependent prostate cancer cell self-renewal in vivo. The intratumoral administration of CpG-RELAsiRNA or CpG-STAT3siRNA but not control conjugates inhibited growth of established prostate tumors and reduced clonogenic potential of cancer cells. Overcoming cancer cell self-renewal and tumor-propagating potential by targeted inhibition of TLR9 signaling can provide therapeutic strategy for late-stage prostate cancer patients.
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Affiliation(s)
- Dayson Moreira
- Department of Cancer Immunotherapeutics & Tumor Immunology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Qifang Zhang
- Department of Cancer Immunotherapeutics & Tumor Immunology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Dewan Md S Hossain
- Department of Cancer Immunotherapeutics & Tumor Immunology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Sergey Nechaev
- Department of Cancer Immunotherapeutics & Tumor Immunology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA.,Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Haiqing Li
- Bioinformatics Core Facility, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Claudia M Kowolik
- Department of Molecular Medicine, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Massimo D'Apuzzo
- Department of Pathology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Stephen Forman
- Department of Hematologic Malignancies, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Jeremy Jones
- Department of Cell Biology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Sumanta K Pal
- Department of Medical Oncology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
| | - Marcin Kortylewski
- Department of Cancer Immunotherapeutics & Tumor Immunology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
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Hossain DMS, Moreira D, Jones J, Pal SK, Kortylewski M. 216. TLR9-Targeted STAT3 Silencing Abrogates Immunosuppressive Activity of Myeloid-Derived Suppressor Cells from Prostate Cancer Patients. Mol Ther 2015. [DOI: 10.1016/s1525-0016(16)33821-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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