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Zhang Z, Xiang S, Cui R, Peng H, Mridul R, Xiang M. ILP-2: A New Bane and Therapeutic Target for Human Cancers. Front Oncol 2022; 12:922596. [PMID: 35814477 PMCID: PMC9260022 DOI: 10.3389/fonc.2022.922596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/26/2022] [Indexed: 12/24/2022] Open
Abstract
Inhibitor of apoptosis protein-related-like protein-2 (ILP-2), also known as BIRC-8, is a member of the inhibitor of apoptosis protein (IAPs) family, which mainly encodes the negative regulator of apoptosis. It is selectively overexpressed in a variety of human tumors and can help tumor cells evade apoptosis, promote tumor cell growth, increase tumor cell aggressiveness, and appears to be involved in tumor cell resistance to chemotherapeutic drugs. Several studies have shown that downregulation of ILP-2 expression increases apoptosis, inhibits metastasis, reduces cell growth potential, and sensitizes tumor cells to chemotherapeutic drugs. In addition, ILP-2 inhibits apoptosis in a unique manner; it does not directly inhibit the activity of caspases but induces apoptosis by cooperating with other apoptosis-related proteins. Here, we review the current understanding of the various roles of ILP-2 in the apoptotic cascade and explore the use of interfering ILP-2, and the combination of related anti-tumor agents, as a novel strategy for cancer therapy.
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Affiliation(s)
- Zhiliang Zhang
- Department of Biochemistry and Immunology, Medical Research Center, Institute of Medicine, Jishou University, Jishou, China
- The State Ethnic Committee's Key Laboratory of Clinical Engineering Laboratory of Xiangxi Miao Pediatric Tuina, Jishou University, Jishou, China
| | - Siqi Xiang
- Department of Biochemistry and Immunology, Medical Research Center, Institute of Medicine, Jishou University, Jishou, China
- The State Ethnic Committee's Key Laboratory of Clinical Engineering Laboratory of Xiangxi Miao Pediatric Tuina, Jishou University, Jishou, China
| | - Ruxia Cui
- Department of Biochemistry and Immunology, Medical Research Center, Institute of Medicine, Jishou University, Jishou, China
- The State Ethnic Committee's Key Laboratory of Clinical Engineering Laboratory of Xiangxi Miao Pediatric Tuina, Jishou University, Jishou, China
| | - Hang Peng
- Department of Biochemistry and Immunology, Medical Research Center, Institute of Medicine, Jishou University, Jishou, China
- The State Ethnic Committee's Key Laboratory of Clinical Engineering Laboratory of Xiangxi Miao Pediatric Tuina, Jishou University, Jishou, China
| | - Roy Mridul
- Department of Biochemistry and Immunology, Medical Research Center, Institute of Medicine, Jishou University, Jishou, China
- The State Ethnic Committee's Key Laboratory of Clinical Engineering Laboratory of Xiangxi Miao Pediatric Tuina, Jishou University, Jishou, China
| | - Mingjun Xiang
- Department of Biochemistry and Immunology, Medical Research Center, Institute of Medicine, Jishou University, Jishou, China
- The State Ethnic Committee's Key Laboratory of Clinical Engineering Laboratory of Xiangxi Miao Pediatric Tuina, Jishou University, Jishou, China
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Umetani N, Fujimoto A, Takeuchi H, Shinozaki M, Bilchik AJ, Hoon DSB. Allelic imbalance of APAF-1 locus at 12q23 is related to progression of colorectal carcinoma. Oncogene 2004; 23:8292-300. [PMID: 15378005 DOI: 10.1038/sj.onc.1208022] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
APAF-1 gene, located at chromosome locus 12q23, is a key factor in the mitochondrial apoptotic pathway downstream of p53, and is a potential tumor suppressor gene. We hypothesized that APAF-1 gene dysfunction due to allelic imbalance (AI) contributes to the development and progression of colorectal carcinoma (CRC). AI at APAF-1 locus and microsatellite instability (MIN) in CRCs and adenomas were assessed by multiple microsatellite markers. The frequency of AI significantly increased with tumor progression; 0 of 33 (0%) adenomas, 14 of 49 (29%) primary CRCs, and 18 of 34 (53%) liver metastases had AI. A total of 12 metastases were matched with corresponding primary CRCs; in 11 of 12 (92%) pairs, the metastasis had same AI status as the corresponding primary tumor. APAF-1 mRNA transcription level was significantly decreased with AI in liver metastases (P=0.009). Promoter hypermethylation was found in three of 35 (9%) primary CRCs and one of 15 (7%) liver metastases by methylation-specific PCR but was not correlated with AI. MIN was observed in 11 of 49 (23%) primary CRCs and was a favorable prognostic factor. Our results suggest that APAF-1 gene haploinsufficiency caused by AI increases with tumor progression, and relates to hepatic metastasis.
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Affiliation(s)
- Naoyuki Umetani
- Department of Molecular Oncology, John Wayne Cancer Institute, Saint Johns Health Science Center, Santa Monica, CA 90404, USA
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Roberts DL, Merrison W, MacFarlane M, Cohen GM. The inhibitor of apoptosis protein-binding domain of Smac is not essential for its proapoptotic activity. J Cell Biol 2001; 153:221-8. [PMID: 11285287 PMCID: PMC2185525 DOI: 10.1083/jcb.153.1.221] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Smac/DIABLO, a recently identified inhibitor of apoptosis protein (IAP)-binding protein, is released from the mitochondria during apoptosis and reportedly potentiates apoptosis by relieving the inhibition of IAPs on caspases. We now describe the molecular characterization of Smac beta, an alternatively spliced form of Smac, which lacks the mitochondrial-targeting sequence found in Smac and has a cortical distribution in both human embryonic kidney 293 and breast epithelial tumor MCF-7 cells. Smac beta, which binds IAPs in vitro, does not bind IAPs in intact cells due to cellular processing and removal of its NH(2)-terminal IAP-binding domain. Despite its inability to interact with IAPs in cells, processed Smac beta is proapoptotic, as demonstrated by its ability to potentiate apoptosis induced by both death receptor and chemical stimuli. Furthermore, expression of a NH(2)-terminally truncated Smac mutant (Delta75), which lacks the entire IAP-interacting domain, potentiates apoptosis to the same extent as Smac and Smac beta. Our data support the hypothesis that the main proapoptotic function of Smac and Smac beta is due to a mechanism other than IAP binding.
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Affiliation(s)
- Darren L. Roberts
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Wendy Merrison
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Marion MacFarlane
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Gerald M. Cohen
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, United Kingdom
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