Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and Metastasis
CLICs are the dimorphic protein present in both soluble and membrane fractions. As an integral membrane protein, CLICs potentially possess ion channel activity. However, it is not fully clarified what kinds of roles CLICs play in physiological and pathological conditions. In vertebrates, CLICs are c...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Cancers |
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| Online Access: | https://www.mdpi.com/2072-6694/14/19/4890 |
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| author | Saya Ozaki Kanta Mikami Takeharu Kunieda Junya Tanaka |
| author_facet | Saya Ozaki Kanta Mikami Takeharu Kunieda Junya Tanaka |
| author_sort | Saya Ozaki |
| collection | DOAJ |
| description | CLICs are the dimorphic protein present in both soluble and membrane fractions. As an integral membrane protein, CLICs potentially possess ion channel activity. However, it is not fully clarified what kinds of roles CLICs play in physiological and pathological conditions. In vertebrates, CLICs are classified into six classes: CLIC1, 2, 3, 4, 5, and 6. Recently, in silico analyses have revealed that the expression level of CLICs may have prognostic significance in cancer. In this review, we focus on CLIC2, which has received less attention than other CLICs, and discuss its role in the metastasis and invasion of malignant tumor cells. CLIC2 is expressed at higher levels in benign tumors than in malignant ones, most likely preventing tumor cell invasion into surrounding tissues. CLIC2 is also expressed in the vascular endothelial cells of normal tissues and maintains their intercellular adhesive junctions, presumably suppressing the hematogenous metastasis of malignant tumor cells. Surprisingly, CLIC2 is localized in secretory granules and secreted into the extracellular milieu. Secreted CLIC2 binds to MMP14 and inhibits its activity, leading to suppressed MMP2 activity. CLIC4, on the other hand, promotes MMP14 activity. These findings challenge the assumption that CLICs are ion channels, implying that they could be potential new targets for the treatment of malignant tumors. |
| first_indexed | 2024-03-09T21:55:21Z |
| format | Article |
| id | doaj.art-0da6ff26f9564dd580f09e1c1a3aa467 |
| institution | Directory Open Access Journal |
| issn | 2072-6694 |
| language | English |
| last_indexed | 2024-03-09T21:55:21Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Cancers |
| spelling | doaj.art-0da6ff26f9564dd580f09e1c1a3aa4672023-11-23T19:58:20ZengMDPI AGCancers2072-66942022-10-011419489010.3390/cancers14194890Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and MetastasisSaya Ozaki0Kanta Mikami1Takeharu Kunieda2Junya Tanaka3Department of Neurosurgery, Graduate School of Medicine, Ehime University, Toon 791-0295, JapanDepartment of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon 791-0295, JapanDepartment of Neurosurgery, Graduate School of Medicine, Ehime University, Toon 791-0295, JapanDepartment of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon 791-0295, JapanCLICs are the dimorphic protein present in both soluble and membrane fractions. As an integral membrane protein, CLICs potentially possess ion channel activity. However, it is not fully clarified what kinds of roles CLICs play in physiological and pathological conditions. In vertebrates, CLICs are classified into six classes: CLIC1, 2, 3, 4, 5, and 6. Recently, in silico analyses have revealed that the expression level of CLICs may have prognostic significance in cancer. In this review, we focus on CLIC2, which has received less attention than other CLICs, and discuss its role in the metastasis and invasion of malignant tumor cells. CLIC2 is expressed at higher levels in benign tumors than in malignant ones, most likely preventing tumor cell invasion into surrounding tissues. CLIC2 is also expressed in the vascular endothelial cells of normal tissues and maintains their intercellular adhesive junctions, presumably suppressing the hematogenous metastasis of malignant tumor cells. Surprisingly, CLIC2 is localized in secretory granules and secreted into the extracellular milieu. Secreted CLIC2 binds to MMP14 and inhibits its activity, leading to suppressed MMP2 activity. CLIC4, on the other hand, promotes MMP14 activity. These findings challenge the assumption that CLICs are ion channels, implying that they could be potential new targets for the treatment of malignant tumors.https://www.mdpi.com/2072-6694/14/19/4890metastasisinvasionMMPMT1-MMPCLIC4glioma |
| spellingShingle | Saya Ozaki Kanta Mikami Takeharu Kunieda Junya Tanaka Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and Metastasis Cancers metastasis invasion MMP MT1-MMP CLIC4 glioma |
| title | Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and Metastasis |
| title_full | Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and Metastasis |
| title_fullStr | Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and Metastasis |
| title_full_unstemmed | Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and Metastasis |
| title_short | Chloride Intracellular Channel Proteins (CLICs) and Malignant Tumor Progression: A Focus on the Preventive Role of CLIC2 in Invasion and Metastasis |
| title_sort | chloride intracellular channel proteins clics and malignant tumor progression a focus on the preventive role of clic2 in invasion and metastasis |
| topic | metastasis invasion MMP MT1-MMP CLIC4 glioma |
| url | https://www.mdpi.com/2072-6694/14/19/4890 |
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