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DNA damage triggers the nuclear accumulation of RASSF6 tumor suppressor protein via CDK9 and BAF53 to regulate p53-target gene transcription. Mol Cell Biol 2021; 42:e0031021. [PMID: 34898277 DOI: 10.1128/mcb.00310-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RASSF6, a member of the tumor suppressor Ras-association domain family (RASSF) proteins, regulates cell cycle arrest and apoptosis via p53 and plays a tumor suppressor role. We previously reported that RASSF6 blocks MDM2-mediated p53 degradation and enhances p53 expression. In this study, we demonstrated that RASSF6 has nuclear-localization and nuclear-export signals and that DNA damage triggers the nuclear accumulation of RASSF6. We found that RASSF6 directly binds to BAF53, the component of SWI/SNF complex. DNA damage induces CDK9-mediated phosphorylation of BAF53, which enhances the interaction with RASSF6 and increases the amount of RASSF6 in the nucleus. Subsequently, RASSF6 augments the interaction between BAF53 and BAF60a, another component of SWI/SNF complex, and further promotes the interaction of BAF53 and BAF60a with p53. BAF53 silencing or BAF60a silencing attenuates RASSF6-mediated p53-target gene transcription and apoptosis. Thus, RASSF6 is involved in the regulation of DNA damage-induced complex formation including CDK9, BAF53, BAF60a, and p53.
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Morishita M, Arimoto-Matsuzaki K, Kitamura M, Niimura K, Iwasa H, Maruyama J, Hiraoka Y, Yamamoto K, Kitagawa M, Miyamura N, Nishina H, Hata Y. Characterization of mouse embryonic fibroblasts derived from Rassf6 knockout mice shows the implication of Rassf6 in the regulation of NF-κB signaling. Genes Cells 2021; 26:999-1013. [PMID: 34652874 DOI: 10.1111/gtc.12901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/10/2021] [Accepted: 10/13/2021] [Indexed: 11/28/2022]
Abstract
RASSF6 is a member of the tumor suppressor Ras association domain family (RASSF) proteins. We have reported using human cancer cell lines that RASSF6 induces apoptosis and cell cycle arrest via p53 and plays tumor suppressive roles. In this study, we generated Rassf6 knockout mice by CRISPR/Cas technology. Contrary to our expectation, Rassf6 knockout mice were apparently healthy. However, Rassf6-null mouse embryonic fibroblasts (MEF) were resistant against ultraviolet (UV)-induced apoptosis/cell cycle arrest and senescence. UV-induced p53-target gene expression was compromised, and DNA repair was delayed in Rassf6-null MEF. More importantly, KRAS active mutant promoted the colony formation of Rassf6-null MEF but not the wild-type MEF. RNA sequencing analysis showed that NF-κB signaling was enhanced in Rassf6-null MEF. Consistently, 7,12-dimethylbenz(a)anthracene (DMBA) induced skin inflammation in Rassf6 knockout mice more remarkably than in the wild-type mice. Hence, Rassf6 deficiency not only compromises p53 function but also enhances NF-κB signaling to lead to oncogenesis.
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Affiliation(s)
- Mayu Morishita
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kyoko Arimoto-Matsuzaki
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masami Kitamura
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kyohei Niimura
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroaki Iwasa
- Department of Molecular Biology, School of Medicine, International University of Health and Welfare, Chiba, Japan
| | - Junichi Maruyama
- Laboratory for Integrated Cellular Systems, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Yuichi Hiraoka
- Laboratory of Genome Editing for Biomedical Research, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kohei Yamamoto
- Department of Comprehensive Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masanobu Kitagawa
- Department of Comprehensive Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Norio Miyamura
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroshi Nishina
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yutaka Hata
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo, Japan
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3
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Iwuchukwu I, Nguyen D, Beavers M, Tran V, Sulaiman W, Fannin E, Lasseigne L, Ramsay E, Wilson J, Bazan NG. MicroRNA Regulatory Network as Biomarkers of Late Seizure in Patients with Spontaneous Intracerebral Hemorrhage. Mol Neurobiol 2020; 57:2346-2357. [PMID: 32040835 DOI: 10.1007/s12035-020-01872-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 09/22/2019] [Indexed: 12/21/2022]
Abstract
Approximately 15% of patients experience seizures after spontaneous intracerebral hemorrhage (ICH). The pathogenesis of seizures post-ICH is not well-known; however, iron deposition-related neuronal injury following hemoglobin breakdown may contribute. Profiling known miRNAs to identify biomarkers for post-ICH late seizures, we found 64 differentially expressed miRNA: 32 upregulated and 32 downregulated in seizure vs. non-seizure. Functional classification of upregulated miRNA for KEGG pathways and biological processes identified enrichment for cell cycle, protein modifications, and FoxO neurotrophin signaling pathways. No significant enrichment was found for downregulated miRNA. Molecular functions Gene Ontology (GO) terms enriched for upregulated miRNA are numerous, while downregulated miRNAs were associated with ion channel activity. RT-PCR confirmed two miRNAs, 4317 and 4325, were differentially expressed in patients who developed seizures at 1 year. MiR-4317 regulates SLC38A1, a glutamine-glutamate transporter. Integrated miRNA-mRNA network analysis identified COMMD6, APOBEC2, and RASSF6-involved in NF-kB regulation. Two miRNAs (miR-4317 and 4325) differentiated post-ICH late seizures vs. non-seizures at 1 year. The results suggest functional and miRNA-mRNA networks as potential biomarkers for post-ICH late seizures.
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Affiliation(s)
- Ifeanyi Iwuchukwu
- Neurocritical Care and Neurology, University of Queensland, Ochsner Clinical School, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA, 70121, USA. .,Institute of Translational Research, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA, 70121, USA. .,Neuroscience Center of Excellence, Louisiana State University Health New Orleans, School of Medicine, 2020 Gravier Street, 8th Floor, New Orleans, LA, 70112, USA.
| | - Doan Nguyen
- Institute of Translational Research, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA, 70121, USA
| | - Michelle Beavers
- Institute of Translational Research, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA, 70121, USA
| | - Vi Tran
- Institute of Translational Research, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA, 70121, USA
| | - Wale Sulaiman
- Neurosurgery, Ochsner Neuroscience Institute, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA, 70121, USA
| | - Erin Fannin
- Department of Neurosurgery, Louisiana State University Health New Orleans, School of Medicine, 2020 Gravier Street, 7th Floor, New Orleans, LA, 70112, USA
| | - Lindsay Lasseigne
- Department of Neurosurgery, Louisiana State University Health New Orleans, School of Medicine, 2020 Gravier Street, 7th Floor, New Orleans, LA, 70112, USA
| | - Eugene Ramsay
- Neurocritical Care and Neurology, University of Queensland, Ochsner Clinical School, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA, 70121, USA
| | - Jason Wilson
- Department of Neurosurgery, Louisiana State University Health New Orleans, School of Medicine, 2020 Gravier Street, 7th Floor, New Orleans, LA, 70112, USA
| | - Nicolas G Bazan
- Neuroscience Center of Excellence, Louisiana State University Health New Orleans, School of Medicine, 2020 Gravier Street, 8th Floor, New Orleans, LA, 70112, USA
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RASSF6-TRIM16 axis promotes cell proliferation, migration and invasion in esophageal squamous cell carcinoma. J Genet Genomics 2019; 46:477-488. [PMID: 31812473 DOI: 10.1016/j.jgg.2019.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/21/2019] [Accepted: 10/17/2019] [Indexed: 01/26/2023]
Abstract
Ras-association (RA) domain family number 6 (RASSF6) is a member of the Ras-association domain protein family. It is epigenetically inactive and negatively regulates the malignant progression of some tumors. However, its precise role in esophageal squamous cell carcinoma (ESCC) has not been reported. In this study, we performed immunohistochemistry (IHC) assay. The results show that RASSF6 is upregulated in ESCC and that the elevated expression level of RASSF6 is associated with lymph node metastasis and poor survival of ESCC patients. Consistent with the clinical observations, the upregulation of RASSF6 greatly promotes ESCC cell proliferation, migration and invasion as well as the cell cycle transition to G1/S phase in vitro. According to models in vivo, the downregulation of RASSF6 considerably inhibits ESCC tumor growth and lung metastasis. Mechanistically, RASSF6 negatively regulates the tumor suppressor tripartite-motif-containing protein 16 (TRIM16) by promoting its ubiquitination-dependent degradation and eventually activates pathways associated with the cell cycle and epithelial-mesenchymal transition (EMT). Together, these results indicate that the RASSF6-TRIM16 axis is a key effector in ESCC progression and that RASSF6 serves as a potential target for the treatment of ESCC.
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5
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Lanfredini S, Thapa A, O'Neill E. RAS in pancreatic cancer. Biochem Soc Trans 2019; 47:961-972. [PMID: 31341034 DOI: 10.1042/bst20170521] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 12/16/2022]
Abstract
The pancreas is a gland composed mainly by endocrine and exocrine cells, giving rise to three main tumour types. Pancreatic neuroendocrine tumour or PNET arise from the endocrine portion of the pancreas. On the contrary, pancreatic exocrine neoplasms include pancreatic ductal adenocarcinoma (PDAC) and acinar cell carcinoma. PDAC is the most common type of pancreatic cancer and one of the leading causes of cancer-related death. It has been shown that less than 3% of PDAC patients have an overall survival of up to 5 years in the U.K. This mainly arises since the majority of patients diagnosed with PDAC present with advanced unresectable disease, which is highly resistant to all forms of chemotherapy and radiotherapy. Activating mutations of an isoform of the RAS protein, KRAS, are found in almost all PDAC cases and occur during early stages of malignant transformation. KRAS mutations play a critical role as they are involved in both initiating and maintaining PDAC development. The interaction of RAS with GDP/GTP along with its recruitment to the membrane affects transduction of its activating signals to downstream effectors. In this review, we aim to summarise different mutations of RAS and their prevalence in pancreatic cancer along with other RAS-induced tumours. In addition, we briefly discuss the genetically engineered mouse models that have been developed to study KRAS-mutated adenocarcinomas in the pancreas. These provide an opportunity to also address the importance of targeting RAS for better treatment response in PDAC patients along with the challenges incurred herein.
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Affiliation(s)
- Simone Lanfredini
- Department of Oncology, Old Road Campus Research Building Roosevelt Drive, University of Oxford, Oxford, U.K
| | - Asmita Thapa
- Department of Oncology, Old Road Campus Research Building Roosevelt Drive, University of Oxford, Oxford, U.K
| | - Eric O'Neill
- Department of Oncology, Old Road Campus Research Building Roosevelt Drive, University of Oxford, Oxford, U.K.
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Wang H, Yan B, Zhang P, Liu S, Li Q, Yang J, Yang F, Chen E. MiR-496 promotes migration and epithelial-mesenchymal transition by targeting RASSF6 in colorectal cancer. J Cell Physiol 2019; 235:1469-1479. [PMID: 31273789 DOI: 10.1002/jcp.29066] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/18/2019] [Indexed: 01/03/2023]
Abstract
Aberrant loss of tumor-suppressor genes plays a crucial role in tumorigenesis and development of colorectal cancer (CRC). Extensive studies have reported tha hypermethylation of Ras association domain family member 6 (RASSF6) is common in various solid tumors. Another important mode of epigenetic regulation, microRNA (miRNA) regulation of RASSF6, is far from clear. The aim of the present work was to screen out novel miRNA regulating RASSF6, and to explore its underlying mechanism in CRC. With the use of bioinformatics, clinical sample data, and luciferase binding assay, we determined that microRNA-496 (miR-496) could be a novel oncomiR that directly binds to RASSF6. Next, a series of miR-496 mimics or inhibitor, or RASSF6 small interfering RNA (siRNA) introduced into CRC cells were applied to examine the effect of miR-496 on CRC cell viability, migration, and epithelial-mesenchymal transition (EMT). The results demonstrated that miR-496/RASSF6 could promote cell migration and EMT via Wnt signaling activation, but had no effect on cell viability. Our results confirmed that the miR-496/RASSF6 axis is involved in Wnt pathway-mediated tumor metastasis, highlighting its potential as a therapeutic target for CRC.
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Affiliation(s)
- Hua Wang
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
| | - Bianbian Yan
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
| | - Pan Zhang
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
| | - Shuzhen Liu
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
| | - Qiqi Li
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
| | - Jin Yang
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
| | - Fangfang Yang
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
| | - Erfei Chen
- Institute of Preventive Genomic Medicine, School of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, China
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7
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The RASSF6 Tumor Suppressor Protein Regulates Apoptosis and Cell Cycle Progression via Retinoblastoma Protein. Mol Cell Biol 2018; 38:MCB.00046-18. [PMID: 29891515 DOI: 10.1128/mcb.00046-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/07/2018] [Indexed: 02/06/2023] Open
Abstract
RASSF6 is a member of the tumor suppressor Ras association domain family (RASSF) proteins. RASSF6 is frequently suppressed in human cancers, and its low expression level is associated with poor prognosis. RASSF6 regulates cell cycle arrest and apoptosis and plays a tumor suppressor role. Mechanistically, RASSF6 blocks MDM2-mediated p53 degradation and enhances p53 expression. However, RASSF6 also induces cell cycle arrest and apoptosis in a p53-negative background, which implies that the tumor suppressor function of RASSF6 does not depend solely on p53. In this study, we revealed that RASSF6 mediates cell cycle arrest and apoptosis via pRb. RASSF6 enhances the interaction between pRb and protein phosphatase. RASSF6 also enhances P16INK4A and P14ARF expression by suppressing BMI1. In this way, RASSF6 increases unphosphorylated pRb and augments the interaction between pRb and E2F1. Moreover, RASSF6 induces TP73 target genes via pRb and E2F1 in a p53-negative background. Finally, we confirmed that RASSF6 depletion induces polyploid cells in p53-negative HCT116 cells. In conclusion, RASSF6 behaves as a tumor suppressor in cancers with loss of function of p53, and pRb is implicated in this function of RASSF6.
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8
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Hippo pathway affects survival of cancer patients: extensive analysis of TCGA data and review of literature. Sci Rep 2018; 8:10623. [PMID: 30006603 PMCID: PMC6045671 DOI: 10.1038/s41598-018-28928-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/29/2018] [Indexed: 12/12/2022] Open
Abstract
The disruption of the Hippo pathway occurs in many cancer types and is associated with cancer progression. Herein, we investigated the impact of 32 Hippo genes on overall survival (OS) of cancer patients, by both analysing data from The Cancer Genome Atlas (TCGA) and reviewing the related literature. mRNA and protein expression data of all solid tumors except pure sarcomas were downloaded from TCGA database. Thirty-two Hippo genes were considered; for each gene, patients were dichotomized based on median expression value. Survival analyses were performed to identify independent predictors, taking into account the main clinical-pathological features affecting OS. Finally, independent predictors were correlated with YAP1 oncoprotein expression. At least one of the Hippo genes is an independent prognostic factor in 12 out of 13 considered tumor datasets. mRNA levels of the independent predictors coherently correlate with YAP1 in glioma, kidney renal clear cell, head and neck, and bladder cancer. Moreover, literature data revealed the association between YAP1 levels and OS in gastric, colorectal, hepatocellular, pancreatic, and lung cancer. Herein, we identified cancers in which Hippo pathway affects OS; these cancers should be candidates for YAP1 inhibitors development and testing.
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Iwasa H, Hossain S, Hata Y. Tumor suppressor C-RASSF proteins. Cell Mol Life Sci 2018; 75:1773-1787. [PMID: 29353317 PMCID: PMC11105443 DOI: 10.1007/s00018-018-2756-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/05/2018] [Accepted: 01/17/2018] [Indexed: 12/13/2022]
Abstract
Human genome has ten genes that are collectedly called Ras association domain family (RASSF). RASSF is composed of two subclasses, C-RASSF and N-RASSF. Both N-RASSF and C-RASSF encode Ras association domain-containing proteins and are frequently suppressed by DNA hypermethylation in human cancers. However, C-RASSF and N-RASSF are quite different. Six C-RASSF proteins (RASSF1-6) are characterized by a C-terminal coiled-coil motif named Salvador/RASSF/Hippo domain, while four N-RASSF proteins (RASSF7-10) lack it. C-RASSF proteins interact with mammalian Ste20-like kinases-the core kinases of the tumor suppressor Hippo pathway-and cross-talk with this pathway. Some of them share the same interacting molecules such as MDM2 and exert the tumor suppressor role in similar manners. Nevertheless, each C-RASSF protein has distinct characters. In this review, we summarize our current knowledge of how C-RASSF proteins play tumor suppressor roles and discuss the similarities and differences among C-RASSF proteins.
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Affiliation(s)
- Hiroaki Iwasa
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Shakhawoat Hossain
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
- Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Yutaka Hata
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
- Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo, 113-8519, Japan.
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10
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Ba Z, Gu L, Hao S, Wang X, Cheng Z, Nie G. Downregulation of lncRNA CASC2 facilitates osteosarcoma growth and invasion through miR-181a. Cell Prolif 2017; 51. [PMID: 29194827 DOI: 10.1111/cpr.12409] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/16/2017] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Long non-coding RNA cancer susceptibility candidate 2 (CASC2) is a novel lncRNA and has been indicated as playing tumour suppressor gene in several tumours. However, the role of CASC2 in osteosarcoma is still uncovered. MATERIALS AND METHODS The CASC2 and miR-181a expressions were measured via qRT-PCR. CCK-8 assay and colony formation assay were performed to determine the cell growth, and transwell assay was performed to assess the cell invasion. RESULTS We showed that CASC2 expression was downregulated in osteosarcoma samples and cell lines. Moreover, we showed that downregulated expression of CASC2 was correlated with advanced TNM stage. Furthermore, overexpression of CASC2 inhibited osteosarcoma cell proliferation, colony formation, and invasion. In addition, we indicated that ectopic expression of CASC2 suppressed miR-181a expression and enhanced the expression of Ras association domain family member 6 (RASSF6), PTEN and ATM in osteosarcoma cell, which were the direct target gene of miR-181a. Moreover, we indicated that RASSF6 expression was downregulated in osteosarcoma samples and cell lines and downregulated expression of RASSF6 was correlated with advanced TNM stage. We found that the expression of RASSF6 was positively correlated with the expression of CASC2 in osteosarcoma tissues. Ectopic expression of CASC2 suppressed the osteosarcoma cell proliferation, colony formation and invasion through regulating RASSF6 expression. CONCLUSIONS Our data illuminated that CASC2 acted as a tumour suppressor in osteosarcoma progression.
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Affiliation(s)
- Zhiwen Ba
- Department of Orthopedics, The Fifth Hospital of Harbin, Harbin, Heilongjiang, 150040, China
| | - Lili Gu
- Department of Orthopedics, The Fifth Hospital of Harbin, Harbin, Heilongjiang, 150040, China
| | - Songnan Hao
- Department of Orthopedics, The Fifth Hospital of Harbin, Harbin, Heilongjiang, 150040, China
| | - Xiaofang Wang
- Department of Infectious Disease, The Forth Hospital of Harbin Medical University, Harbin, Heilongjiang, 150001, China
| | - Zhenping Cheng
- Department of Orthopedics, The Fifth Hospital of Harbin, Harbin, Heilongjiang, 150040, China
| | - Guangchen Nie
- Department of Orthopedics, The Fifth Hospital of Harbin, Harbin, Heilongjiang, 150040, China
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Xu X, Iwasa H, Hossain S, Sarkar A, Maruyama J, Arimoto-Matsuzaki K, Hata Y. BCL-XL binds and antagonizes RASSF6 tumor suppressor to suppress p53 expression. Genes Cells 2017; 22:993-1003. [PMID: 29193479 DOI: 10.1111/gtc.12541] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 10/24/2017] [Indexed: 12/11/2022]
Abstract
RASSF6, a member of the tumor suppressor Ras-association domain family proteins, induces apoptosis in the caspase-dependent and caspase-independent manners. RASSF6 interacts with MDM2 and stabilizes p53. BCL-XL is a prosurvival member of BCL-2 family proteins. BCL-XL directly inhibits proapoptotic BAX and BAK. BCL-XL also traps tBID, a proapoptotic activator BH3-only protein, and sequesters p53. In addition, BCL-XL regulates the mitochondrial membrane permeability via voltage-dependent anion channel. In these manners, BCL-XL plays an antiapoptotic role. We report the interaction of BCL-XL with RASSF6. BCL-XL inhibits the interaction between RASSF6 and MDM2 and suppresses p53 expression. Consequently, BCL-XL antagonizes RASSF6-mediated apoptosis. Thus, the inhibition of RASSF6-mediated apoptosis also underlies the prosurvival role of BCL-XL.
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Affiliation(s)
- Xiaoyin Xu
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Breast Oncology Surgery, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Hiroaki Iwasa
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shakhawoat Hossain
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi, Bangladesh
| | - Aradhan Sarkar
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Junichi Maruyama
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kyoko Arimoto-Matsuzaki
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yutaka Hata
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo, Japan
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12
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Decreased level of RASSF6 in sporadic colorectal cancer and its anti-tumor effects both in vitro and in vivo. Oncotarget 2017; 7:19813-23. [PMID: 27009808 PMCID: PMC4991420 DOI: 10.18632/oncotarget.7852] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Accepted: 02/11/2016] [Indexed: 12/24/2022] Open
Abstract
Ras-association domain family protein 6 (RASSF6) is a member of tumor suppressor RASSFs family with a wide range of function from RAS interaction, Hippo signaling involvement to cell cycle and apoptosis regulation. RASSF6 is reported inactivated in various types of cancer. However, whether RASSF6 is associated with colorectal cancer and the underlying mechanisms have yet to be investigated. In our previous exome sequencing study, we found a somatic loss-of-function (LoF) mutation in RASSF6 in one sporadic colorectal cancer (sCRC) patient, and two missense mutations in deep sequencing group of sCRC samples, implying the possibility that RASSF6 may be involved in the pathogenesis of sCRC. In this study, we demonstrate that RASSF6 acts as a tumor suppressor in colon cancer cells. Decreased level of RASSF6 was observed in adenocarcinoma compared to normal tissues, especially in advanced tumor cases. Further experiments showed exogenous introduction of RASSF6 into LoVo cells suppressed cell proliferation, migration, invasion, and induced apoptosis in vitro as well as tumor growth in vivo. In contrast, knockdown of RASSF6 in HT-29 cells showed the opposite effects. Taken together, our results suggest, in addition to epigenetics changes, functional somatic mutations may also contribute to the downregulation of RASSF6 and further participate in the pathogenesis of sCRC. RASSF6 may serve as a novel candidate against tumor growth for sCRC.
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13
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El Gammal AT, Sturm JH, Pinnschmidt HO, Hofmann BT, Bellon E. Protein S100A8/A9: A Potential New Biomarker for Pancreatic Diseases. ACTA ACUST UNITED AC 2017. [DOI: 10.17352/ijcem.000025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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14
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Zhou R, Qiu L, Liu X, Ling L, Li N, Zhou K, Sun J, Yan J, Tan C, Huang X, Han L, Yin L, Xiao G, Liu L. RASSF6 downregulation promotes the epithelial-mesenchymal transition and predicts poor prognosis in colorectal cancer. Oncotarget 2017; 8:55162-55175. [PMID: 28903410 PMCID: PMC5589649 DOI: 10.18632/oncotarget.19181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 06/02/2017] [Indexed: 12/18/2022] Open
Abstract
Distant metastasis is the primary barrier for the successful treatment of patients with colorectal cancer, and thus, searching for new therapeutic targets by further exploring the molecular mechanisms of colorectal cancer metastasis is important. In this study, we investigated the biological and clinical significance of RASSF6 in colorectal cancer as well as the underlying molecular mechanisms. We found that low RASSF6 expression corresponds to a poor prognosis in colorectal cancer patients, and low RASSF6 expression is distinctly associated with tumour progression. Our in vitro analysis revealed that RASSF6 suppresses the proliferation and metastasis of DLD1 cells, and RASSF6 knockdown in HCT116 cells confirmed these observations. Our mechanistic investigation revealed that RASSF6 inhibits the expression of the classical target genes of Wnt signalling, as demonstrated by the reduced expression of TCF1, c-Jun, and c-Myc in RASSF6-overexpressing DLD1 stable cell lines. Furthermore, we show that RASSF6 functions as a negative regulator of the epithelial-mesenchymal transition; the expression levels of the epithelial markers ZO-1 and E-cadherin were increased, while the expression level of the mesenchymal marker Snail was decreased in a RASSF6-overexpressing DLD1 cell line. Additionally, rescue assays revealed that the activation of Wnt signalling by LiCl treatment impaired the inhibitory effect of RASSF6 on the proliferation and metastasis of colorectal cancer cells, which implies that RASSF6 suppresses the tumorigenicity of colorectal cancer cells at least in part through inhibiting Wnt signalling pathway. Collectively, these findings provide new perspectives for the future study of RASSF6 as a therapeutic target for colorectal cancer.
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Affiliation(s)
- Rui Zhou
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Lin Qiu
- Department of Hematology/Oncology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Xiaolong Liu
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Lijuan Ling
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Ninglei Li
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Kun Zhou
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Jingbo Sun
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Jian Yan
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Canliang Tan
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Xiaoping Huang
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Luzhe Han
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Liangchun Yin
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Gang Xiao
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Lixin Liu
- Department of General Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
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15
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Schorn S, Demir IE, Haller B, Scheufele F, Reyes CM, Tieftrunk E, Sargut M, Goess R, Friess H, Ceyhan GO. The influence of neural invasion on survival and tumor recurrence in pancreatic ductal adenocarcinoma - A systematic review and meta-analysis. Surg Oncol 2017; 26:105-115. [PMID: 28317579 DOI: 10.1016/j.suronc.2017.01.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 01/28/2017] [Accepted: 01/31/2017] [Indexed: 12/18/2022]
Abstract
OBJECTIVES To assess the impact of neural invasion/NI on overall survival/OS and tumor recurrence in pancreatic ductal adenocarcinoma/PDAC. SUMMARY BACKGROUND DATA NI is a histopathological hallmark of PDAC. Although some studies suggested an important role for NI on OS, disease-free/DFS and progression-free survival/PFS in PDAC, there is still no consensus on the actual role of NI on survival and local recurrence in PDAC. METHODS Pubmed, Cochrane library, Ovid and Google Scholar were screened for the terms "pancreatic ductal adenocarcinoma", "pancreatic cancer", "survival", "tumor recurrence" and "perineural invasion". The Preferred-Reporting-Items-for-Systematic-review-and-Meta-Analysis/PRISMA-guidelines were used for systematic review and meta-analysis. Articles meeting predefined criteria were critically analysed on relevance, and meta-analyses were performed by pooling univariate and multivariate hazard ratios/HR. RESULTS A total number of 25 studies on the influence of NI on tumor recurrence, and 121 studies analysing the influence of NI on survival were identified by systematic review. The HR of the univariate (HR 1.88; 95%-CI 1.71-2.07; p < 0.00001) and multivariate meta-analysis (HR 1.68; 95%-CI 1.47-1.92; p < 0.00001) showed a major impact of NI on OS. Likewise, NI was associated with decreased DFS (HR 2.53; 95%-CI: 1.67-3.83; p = 0.0001) and PFS (HR 2.41; 95%-CI: 1.73-3.37: p < 0.00001) multivariate meta-analysis. CONCLUSIONS Although the power of this study is limited by missing pathological procedures to assess the true incidence of NI, NI appears to be an independent prognostic factor for OS, DFS and PFS in PDAC. Therefore, NI should be increasingly considered in patient stratification and in the development of novel therapeutic algorithms.
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Affiliation(s)
- Stephan Schorn
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Ihsan Ekin Demir
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Bernhard Haller
- Institute of Medical Statistics and Epidemiology, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany
| | - Florian Scheufele
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Carmen Mota Reyes
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Elke Tieftrunk
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Mine Sargut
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Ruediger Goess
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Helmut Friess
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Güralp Onur Ceyhan
- Department of Surgery, Klinikum Rechts der Isar, Technical University of Munich, Germany.
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16
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Słotwiński R, Słotwińska SM. Diagnostic value of selected markers and apoptotic pathways for pancreatic cancer. Cent Eur J Immunol 2017; 41:392-403. [PMID: 28450803 PMCID: PMC5382885 DOI: 10.5114/ceji.2016.65139] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 09/26/2016] [Indexed: 12/19/2022] Open
Abstract
Pancreatic cancer occupies the fourth place as a cause of death from cancer, and the mortality rate is similar to the number of newly detected cases. Due to the late diagnosis, only 5-6% of patients with pancreatic cancer survive for five years. Given that early diagnosis is critical for improving patients' survival rates, there is an urgent need for the discovery and validation of new biomarkers with sufficient sensitivity and specificity to help diagnose pancreatic cancer early. Detection of serum tumor markers (CA19-9, CEA, CA125 and CA242) is conducive to the early diagnosis of pancreatic cancer. The combination of miR-16, miR-196a and CA19-9 plasma level was more effective, especially in early tumor screening. Furthermore, recent studies reported that mainly miR-21, miR-155 and miR-196 were dysregulated in IPMN (intraductal papillary mucinous neoplasms) and PanIN (pancreatic intraepithelial neoplasia) lesions, suggesting their usefulness as early biomarkers of these diseases. The reduced rate of apoptosis plays a crucial role in carcinogenesis, and it is one of the most important characteristics acquired by pancreatic cancer cells, which protects them from attack by the immune system and reduces the effectiveness of pharmacological treatment. This review summarizes the data concerning the clinical utility of selected biomarkers in pancreatic cancer patients. The review mainly focuses on the genetic aspects of signaling pathway disorders associated with apoptosis in the pathogenesis and diagnosis of pancreatic cancer.
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Affiliation(s)
- Robert Słotwiński
- Department of Surgical Research and Transplantology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Poland
- Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Poland
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17
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Sarkar A, Iwasa H, Hossain S, Xu X, Sawada T, Shimizu T, Maruyama J, Arimoto-Matsuzaki K, Hata Y. Domain analysis of Ras-association domain family member 6 upon interaction with MDM2. FEBS Lett 2017; 591:260-272. [DOI: 10.1002/1873-3468.12551] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 12/08/2016] [Accepted: 12/28/2016] [Indexed: 01/02/2023]
Affiliation(s)
- Aradhan Sarkar
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
| | - Hiroaki Iwasa
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
| | - Shakhawoat Hossain
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
- Department of Biochemistry and Molecular Biology; University of Rajshahi; Bangladesh
| | - Xiaoyin Xu
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
- Department of Breast Oncology Surgery; The Second Affiliated Hospital of Wenzhou Medical University; China
| | - Takeru Sawada
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
| | - Takanobu Shimizu
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
| | - Junichi Maruyama
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
| | - Kyoko Arimoto-Matsuzaki
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
| | - Yutaka Hata
- Department of Medical Biochemistry; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Japan
- Center for Brain Integration Research; Tokyo Medical and Dental University; Japan
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18
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Mi Y, Zhang D, Jiang W, Weng J, Zhou C, Huang K, Tang H, Yu Y, Liu X, Cui W, Zhang M, Sun X, Zhou Z, Peng Z, Zhao S, Wen Y. miR-181a-5p promotes the progression of gastric cancer via RASSF6-mediated MAPK signalling activation. Cancer Lett 2016; 389:11-22. [PMID: 28043911 DOI: 10.1016/j.canlet.2016.12.033] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 02/05/2023]
Abstract
We previously discovered that Ras association domain family member 6 (RASSF6) was downregulated and predicted poor prognosis in GC patients. However, the mechanisms of the down regulation of RASSF6 in GC remained unclear. Increasing evidence indicates that dysregulation of microRNAs promotes the progression of cancer through the repression of tumour suppressors. Here, we identified miR-181a-5p as a novel regulator of RASSF6 in GC. Functionally, ectopic expression or silencing of miR-181a-5p, respectively, promoted or inhibited GC cell proliferation, colony formation and cell cycle transition, as well as enhanced or prevented the invasion, metastasis of GC cells and epithelial to mesenchymal transition of GC cells in vitro and in vivo. Molecularly, miR-181a-5p functioned as an onco-miRNA by activating the RASSF6-regulated MAKP pathway. Overexpression or silencing of RASSF6 could partially reverse the effects of the overexpression or repression of miR-181a-5p on GC progress caused by activation of the MAKP pathway in vitro and in vivo. Clinically, high miR-181a-5p expression predicted poor survival in GC patients, especially combined with low RASSF6 expression. Collectively, we identified miR-181a-5p as an onco-miRNA, which acts by directly repressing RASSF6 in GC.
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Affiliation(s)
- Yushuai Mi
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Dongyuan Zhang
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Weiliang Jiang
- Department of Gastroenterology, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Junyong Weng
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Chongzhi Zhou
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Kejian Huang
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Huamei Tang
- Department of Pathology, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Yang Yu
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Xisheng Liu
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Weiyingqi Cui
- Department of Oncology, Linköping University, Linköping, Sweden; Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
| | - Meng Zhang
- Department of Pathology, Shanghai Cancer Center, Fudan University, Shanghai, China.
| | - Xiaofeng Sun
- Department of Oncology, Linköping University, Linköping, Sweden; Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
| | - Zongguang Zhou
- Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Zhihai Peng
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Senlin Zhao
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Yugang Wen
- Department of General Surgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
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19
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Zhu N, Si M, Yang N, Jing Y, Fu Y, Zhao X, Lin Z, Yang G. Overexpression of RAS-Association Domain Family 6 (RASSF6) Inhibits Proliferation and Tumorigenesis in Hepatocellular Carcinoma Cells. Oncol Res 2016; 25:1001-1008. [PMID: 27983932 PMCID: PMC7841125 DOI: 10.3727/096504016x14796039599926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ras-association domain family 6 (RASSF6), a member of the RASSF family, is frequently downregulated in various types of cancer. However, the roles of RASSF6 in human hepatocellular carcinoma (HCC) are still unclear. In this study, we investigated the biological functions and related molecular mechanisms in HCC. Our results found that RASSF6 is expressed in low amounts in HCC tissues and cell lines. Overexpression of RASSF6 obviously inhibited the proliferation, invasion, and EMT process in HCC cells. Furthermore, overexpression of RASFF6 greatly downregulated the protein levels of phosphorylated focal adhesion kinase (FAK), MMP-2, and MMP-9 in HepG2 cells. Last, overexpression of RASFF6 significantly attenuated tumor growth in Balb/c nude mice. In conclusion, the present study revealed that RASFF6 can inhibit the proliferation, invasion, and migration of HCC cells both in vivo and in vitro. These inhibitory effects are through suppressing FAK phosphorylation, leading to decreased MMP-2/9 expression. RASFF6 is therefore a potential therapeutic target for treating HCC.
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20
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Iwasa H, Jiang X, Hata Y. RASSF6; the Putative Tumor Suppressor of the RASSF Family. Cancers (Basel) 2015; 7:2415-26. [PMID: 26690221 PMCID: PMC4695899 DOI: 10.3390/cancers7040899] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/01/2015] [Accepted: 12/01/2015] [Indexed: 11/16/2022] Open
Abstract
Humans have 10 genes that belong to the Ras association (RA) domain family (RASSF). Among them, RASSF7 to RASSF10 have the RA domain in the N-terminal region and are called the N-RASSF proteins. In contradistinction to them, RASSF1 to RASSF6 are referred to as the C-RASSF proteins. The C-RASSF proteins have the RA domain in the middle region and the Salvador/RASSF/Hippo domain in the C-terminal region. RASSF6 additionally harbors the PSD-95/Discs large/ZO-1 (PDZ)-binding motif. Expression of RASSF6 is epigenetically suppressed in human cancers and is generally regarded as a tumor suppressor. RASSF6 induces caspase-dependent and -independent apoptosis. RASSF6 interacts with mammalian Ste20-like kinases (homologs of Drosophila Hippo) and cross-talks with the Hippo pathway. RASSF6 binds MDM2 and regulates p53 expression. The interactions with Ras and Modulator of apoptosis 1 (MOAP1) are also suggested by heterologous protein-protein interaction experiments. RASSF6 regulates apoptosis and cell cycle through these protein-protein interactions, and is implicated in the NF-κB and JNK signaling pathways. We summarize our current knowledge about RASSF6 and discuss what common and different properties RASSF6 and the other C-RASSF proteins have.
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Affiliation(s)
- Hiroaki Iwasa
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan.
| | - Xinliang Jiang
- Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo 113-8510, Japan.
| | - Yutaka Hata
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan.
- Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo 113-8510, Japan.
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