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Arakaki R, Yamasaki T, Kanno T, Shibasaki N, Sakamoto H, Utsunomiya N, Sumiyoshi T, Shibuya S, Tsuruyama T, Nakamura E, Ogawa O, Kamba T. CCL2 as a potential therapeutic target for clear cell renal cell carcinoma. Cancer Med 2016; 5:2920-2933. [PMID: 27666332 PMCID: PMC5083746 DOI: 10.1002/cam4.886] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [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: 02/26/2016] [Revised: 07/07/2016] [Accepted: 08/01/2016] [Indexed: 12/21/2022] Open
Abstract
We previously reported that the pVHL‐atypical PKC‐JunB pathway contributed to promotion of cell invasiveness and angiogenesis in clear cell renal cell carcinoma (ccRCC), and we detected chemokine (C‐C motif) ligand‐2 (CCL2) as one of downstream effectors of JunB. CCL2 plays a critical role in tumorigenesis in other types of cancer, but its role in ccRCC remains unclear. In this study, we investigated the roles and therapeutic potential of CCL2 in ccRCC. Immunohistochemical analysis of CCL2 expression for ccRCC specimens showed that upregulation of CCL2 expression correlated with clinical stage, overall survival, and macrophage infiltration. For functional analysis of CCL2 in ccRCC cells, we generated subclones of WT8 cells that overexpressed CCL2 and subclones 786‐O cells in which CCL2 expression was knocked down. Although CCL2 expression did not affect cell proliferation in vitro, CCL2 overexpression enhanced and CCL2 knockdown suppressed tumor growth, angiogenesis, and macrophage infiltration in vivo. We then depleted macrophages from tumor xenografts by administration of clodronate liposomes to confirm the role of macrophages in ccRCC. Depletion of macrophages suppressed tumor growth and angiogenesis. To examine the effect of inhibiting CCL2 activity in ccRCC, we administered CCL2 neutralizing antibody to primary RCC xenografts established from patient surgical specimens. Inhibition of CCL2 activity resulted in significant suppression of tumor growth, angiogenesis, and macrophage infiltration. These results suggest that CCL2 is involved in angiogenesis and macrophage infiltration in ccRCC, and that CCL2 could be a potential therapeutic target for ccRCC.
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Affiliation(s)
- Ryuichiro Arakaki
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Toshinari Yamasaki
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Toru Kanno
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Noboru Shibasaki
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hiromasa Sakamoto
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Noriaki Utsunomiya
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takayuki Sumiyoshi
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shinsuke Shibuya
- Department of Diagnostic Pathology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tatsuaki Tsuruyama
- Department of Diagnostic Pathology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Eijiro Nakamura
- Laboratory for Malignancy Control Research/Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Osamu Ogawa
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tomomi Kamba
- Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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