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Zhang Y, Chen Y, Guo Q, Zhang Y, Liu A. Fat mass and obesity-associated protein (FTO)-induced upregulation of flotillin-2 (FLOT2) contributes to cancer aggressiveness in diffuse large B-cell lymphoma (DLBCL) via activating the PI3K/Akt/mTOR signal pathway. Arch Biochem Biophys 2024; 758:110072. [PMID: 38914215 DOI: 10.1016/j.abb.2024.110072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 06/11/2024] [Accepted: 06/21/2024] [Indexed: 06/26/2024]
Abstract
The role of fat mass and obesity-associated protein (FTO)-mediated N6-methyladenosine (m6A)-demethylation has been investigated in various types of cancers, but it is still unclear whether FTO participates in the progression of diffuse large B-cell lymphoma (DLBCL). Here, by conducting Real-Time qPCR and Western Blot analysis, we verified that FTO was especially enriched in the DLBCL cells (RCK-8, LY-3, DHL-6 and U2932) compared to normal WIL2S cells. Then, the overexpression and silencing vectors for FTO were delivered into the LY-3 and U2932 cells, and our functional experiments confirmed that silencing of FTO suppressed cell viability and division, and induced apoptotic cell death in the DLBCL cells, whereas FTO-overexpression exerted opposite effects. Further mechanical experiments showed that FTO demethylated m6A modifications in flotillin-2 (FLOT2) mRNA to sustain its stability for FLOT2 upregulation, and elevated FLOT2 subsequently increased the expression levels of phosphorylated PI3K (p-PI3K), p-Akt and p-mTOR to activate the tumor-initiating PI3K/Akt/mTOR signal pathway. Of note, FLOT2 also serve as an oncogene to enhance cancer malignancy in DLBCL, and the rescuing experiments showed that FTO-ablation induced suppressing effects on the malignant phenotypes in DLBCL were all abrogated by overexpressing FLOT2. Taken together, those data hinted that FTO-mediated m6A-demethylation upregulated FLOT2 to activate the downstream PI3K/Akt/mTOR signal pathway, leading to the aggressiveness of DLBCL, which potentially provided diagnostic, therapeutic and prognostic biomarkers for DLBCL.
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Affiliation(s)
- Yujing Zhang
- Hemolymph Department, Harbin Medical University Cancer Hospital, Harbin, China; Department of Hematology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China.
| | - Yao Chen
- Hemolymph Department, Harbin Medical University Cancer Hospital, Harbin, China.
| | - Qiang Guo
- Department of Hematology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China.
| | - Ying Zhang
- Department of Hematology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China.
| | - Aichun Liu
- Hemolymph Department, Harbin Medical University Cancer Hospital, Harbin, China.
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Wisniewski DJ, Liyasova MS, Korrapati S, Zhang X, Ratnayake S, Chen Q, Gilbert SF, Catalano A, Voeller D, Meerzaman D, Guha U, Porat-Shliom N, Annunziata CM, Lipkowitz S. Flotillin-2 regulates epidermal growth factor receptor activation, degradation by Cbl-mediated ubiquitination, and cancer growth. J Biol Chem 2023; 299:102766. [PMID: 36470425 PMCID: PMC9823131 DOI: 10.1016/j.jbc.2022.102766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 12/08/2022] Open
Abstract
Epidermal growth factor receptor (EGFR) signaling is frequently dysregulated in various cancers. The ubiquitin ligase Casitas B-lineage lymphoma proto-oncogene (Cbl) regulates degradation of activated EGFR through ubiquitination and acts as an adaptor to recruit proteins required for trafficking. Here, we used stable isotope labeling with amino acids in cell culture mass spectrometry to compare Cbl complexes with or without epidermal growth factor (EGF) stimulation. We identified over a hundred novel Cbl interactors, and a secondary siRNA screen found that knockdown of Flotillin-2 (FLOT2) led to increased phosphorylation and degradation of EGFR upon EGF stimulation in HeLa cells. In PC9 and H441 cells, FLOT2 knockdown increased EGF-stimulated EGFR phosphorylation, ubiquitination, and downstream signaling, reversible by EGFR inhibitor erlotinib. CRISPR knockout (KO) of FLOT2 in HeLa cells confirmed EGFR downregulation, increased signaling, and increased dimerization and endosomal trafficking. Furthermore, we determined that FLOT2 interacted with both Cbl and EGFR. EGFR downregulation upon FLOT2 loss was Cbl dependent, as coknockdown of Cbl and Cbl-b restored EGFR levels. In addition, FLOT2 overexpression decreased EGFR signaling and growth. Overexpression of wildtype (WT) FLOT2, but not the soluble G2A FLOT2 mutant, inhibited EGFR phosphorylation upon EGF stimulation in HEK293T cells. FLOT2 loss induced EGFR-dependent proliferation and anchorage-independent growth. Lastly, FLOT2 KO increased tumor formation and tumor volume in nude mice and NSG mice, respectively. Together, these data demonstrated that FLOT2 negatively regulated EGFR activation and dimerization, as well as its subsequent ubiquitination, endosomal trafficking, and degradation, leading to reduced proliferation in vitro and in vivo.
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Affiliation(s)
- David J Wisniewski
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Mariya S Liyasova
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Soumya Korrapati
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Xu Zhang
- Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Shashikala Ratnayake
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, Maryland, USA
| | - Qingrong Chen
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, Maryland, USA
| | - Samuel F Gilbert
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Alexis Catalano
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Donna Voeller
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Daoud Meerzaman
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, Maryland, USA
| | - Udayan Guha
- Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Natalie Porat-Shliom
- Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Christina M Annunziata
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Stanley Lipkowitz
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA.
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Effect of FLOT2 Gene Expression on Invasion and Metastasis of Colorectal Cancer and Its Molecular Mechanism under Nanotechnology and RNA Interference. BIOMED RESEARCH INTERNATIONAL 2022; 2022:2897338. [PMID: 35419458 PMCID: PMC9001092 DOI: 10.1155/2022/2897338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 11/18/2022]
Abstract
The study is aimed at investigating the effect of the FLOT2 gene on invasion and metastasis of colorectal cancer (CRC) cells and the corresponding molecular mechanism by preparing polylysine-silicon nanoparticles. Specifically, polylysine was used to modify the silica nanoparticles prepared by the emulsification method to obtain polylysine-silicon nanoparticles. The characterization of polylysine-silicon nanoparticles was completed by nanoparticle size analyzer, laser particle size potentiometer, and transmission microscope. The influence of polylysine-silicon nanoparticles on the survival rate of CRC cell line HT-29 was detected using the method of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). The FLOT2-siRNA expression vector was constructed and transfected with HT-29. The HT-29 transfected with empty plasmid was used as the negative control (NC). Western Blot (WB) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect expression levels of FLOT2 gene and epithelial-mesenchymal transition- (EMT-) related genes. Transwell invasion assay, Transwell migration assay, and CCK8 assay were used to detect the cell invasion, migration, and proliferation. The results showed that the average particle size of polylysine-silicon nanoparticles was 30 nm, the potential was 19.65 mV, the particle size was 65.8 nm, and the dispersion coefficient was 0.103. At the same concentration, the toxicity of silicon nanoparticles to HT-29 was significantly lower than that of liposome reagent, and the transfection efficiency was 60%, higher than that of liposome reagent (40%). The mRNA level and protein expression of the FLOT2 gene in the FLOT2-siRNA group were significantly lower than those in the NC group (P < 0.01). The optical density (OD) value of the NC group and the blank control (CK) group were significantly higher than that of FLOT2-siRNA cells (P < 0.01). The OD value of FLOT2-siRNA cells was lower than that of NC cells at 48 h, 72 h, and 96 h (P < 0.01). The mRNA levels and protein expressions of MMP2 and vimentin in the FLOT2-siRNA group were significantly lower than those in the NC group and CK group (P < 0.01). The mRNA level and protein expression of the E-cadherin gene in the FLOT2-siRNA group were significantly higher than those in the NC group and CK group (P < 0.01). In conclusion, an RNA interference plasmid with high transfection efficiency and low cytotoxicity was established based on nanotechnology. siRNA-mediated FLOT2 protein inhibits the invasion, migration, and proliferation of CRC cells by regulating the expression changes of EMT-related genes, which provides a scientific basis for clinical treatment of CRC.
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Liu R, Liu J, Wu P, Yi H, Zhang B, Huang W. Flotillin-2 promotes cell proliferation via activating the c-Myc/BCAT1 axis by suppressing miR-33b-5p in nasopharyngeal carcinoma. Aging (Albany NY) 2021; 13:8078-8094. [PMID: 33744853 PMCID: PMC8034900 DOI: 10.18632/aging.202726] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/09/2021] [Indexed: 04/13/2023]
Abstract
Previously, we elucidated the function of flotilin-2 (FLOT2) and branched-chain amino acid transaminase 1(BCAT1) in nasopharyngeal carcinoma (NPC). However, the relationship between FLOT2 and BCAT1 in promoting NPC progression remains unknown. Here, we observed that FLOT2 upregulated BCAT1 expression in NPC cells. Ectopic expression of BCAT1 significantly antagonized the inhibitory effects on NPC cell proliferation induced by FLOT2 depletion. Consequently, BCAT1 knockdown markedly inhibited the pro-proliferative effects of FLOT2 overexpression in NPC cells. FLOT2 expression was positively correlated with BCAT1 expression in NPC tissues and was inversely correlated with the prognosis of NPC patients. Mechanistically, FLOT2 maintains the expression level of c-Myc, a positive transcription factor of BCAT1, and subsequently promote BCAT1 transcription. FLOT2 inhibited miR-33b-5p in NPC cells and attenuated its inhibitory effects on c-Myc. Further, experimental validation of the function of the FLOT2/miR-33b-5p/c-Myc/BCAT1 axis in regulating NPC cell proliferation was performed. Our results revealed that FLOT2 promotes NPC cell proliferation by suppressing miR-33b-5p, to maintain proper levels of c-Myc, and upregulate BCAT1trancription. Therefore, the FLOT2/miR-33b-5p/c-Myc/BCAT1 axis is a potential therapeutic target for NPC.
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Affiliation(s)
- Rong Liu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- College of Biology and Environmental Sciences, Jishou University, Jishou 416000, China
| | - Jie Liu
- Department of Pathology, Changsha Central Hospital, Changsha 410004, China
| | - Ping Wu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Hong Yi
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Bin Zhang
- Department of Histology and Embryology, School of Basic Medicine, Central South University, Changsha 410013, China
| | - Wei Huang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha 410008, China
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Song T, Hu Z, Liu J, Huang W. FLOT2 upregulation promotes growth and invasion by interacting and stabilizing EphA2 in gliomas. Biochem Biophys Res Commun 2021; 548:67-73. [PMID: 33631676 DOI: 10.1016/j.bbrc.2021.02.062] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 12/13/2022]
Abstract
The expression and roles of FLOT2, especially for its underlying mechanism, in gliomas have been rarely revealed. In this study, upregulations of both FLOT2 and EphA2 in gliomas tissues were validated by immunohistochemistry (IHC) staining and Western blot. FLOT2 silencing notably inhibited the growth and invasion of gliomas cells. Simultaneously, FLOT2 depletion suppressed Akt and NF-κB activities, induced apoptosis, cell cycle arrest, and epithelial-mesenchymal transition (EMT) inhibition, demonstrated by expression alterations of key proteins of the above processes. Mechanistically, FLOT2 could maintain EphA2 stability viainteraction, and restoration of EphA2 could remarkably release the suppressive effects on gliomas cells induced by FLOT2 knockdown. Lastly, FLOT2 and EphA2, whose protein and mRNA levels are both positively correlated in gliomas, shows significant association with clinical characteristics like Ki67 intensity, p53 expression, and tumor stage in patients with gliomas. In conclusion, our results reveal the upregulation, oncogenic roles of FLOT2, and the corresponding underlying mechanism in gliomas, highlighting that the FLOT2-EphA2 axis is served as a promising therapeutic target for gliomas.
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Affiliation(s)
- Tao Song
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhongxu Hu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jie Liu
- Department of Pathology, Changsha Central Hospital, Changsha, Hunan, China
| | - Wei Huang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, China; Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Changsha, Hunan, China.
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Greenlee JD, Subramanian T, Liu K, King MR. Rafting Down the Metastatic Cascade: The Role of Lipid Rafts in Cancer Metastasis, Cell Death, and Clinical Outcomes. Cancer Res 2021; 81:5-17. [PMID: 32999001 PMCID: PMC7952000 DOI: 10.1158/0008-5472.can-20-2199] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/01/2020] [Accepted: 09/21/2020] [Indexed: 11/16/2022]
Abstract
Lipid rafts are tightly packed, cholesterol- and sphingolipid-enriched microdomains within the plasma membrane that play important roles in many pathophysiologic processes. Rafts have been strongly implicated as master regulators of signal transduction in cancer, where raft compartmentalization can promote transmembrane receptor oligomerization, shield proteins from enzymatic degradation, and act as scaffolds to enhance intracellular signaling cascades. Cancer cells have been found to exploit these mechanisms to initiate oncogenic signaling and promote tumor progression. This review highlights the roles of lipid rafts within the metastatic cascade, specifically within tumor angiogenesis, cell adhesion, migration, epithelial-to-mesenchymal transition, and transendothelial migration. In addition, the interplay between lipid rafts and different modes of cancer cell death, including necrosis, apoptosis, and anoikis, will be described. The clinical role of lipid raft-specific proteins, caveolin and flotillin, in assessing patient prognosis and evaluating metastatic potential of various cancers will be presented. Collectively, elucidation of the complex roles of lipid rafts and raft components within the metastatic cascade may be instrumental for therapeutic discovery to curb prometastatic processes.
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Affiliation(s)
- Joshua D Greenlee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Tejas Subramanian
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Kevin Liu
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Michael R King
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.
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Zhu M, Shi W, Chen K, Hu H, Ye X, Jiang Y. Pulsatilla saponin E suppresses viability, migration, invasion and promotes apoptosis of NSCLC cells through negatively regulating Akt/FASN pathway via inhibition of flotillin-2 in lipid raft. J Recept Signal Transduct Res 2020; 42:23-33. [PMID: 33243063 DOI: 10.1080/10799893.2020.1839764] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE Pulsatilla saponins from pulsatilla chinensis (Bunge) Regel have potential anti-tumor activities to certain human cancers. However, the roles of pulsatilla saponin E separated from pulsatilla saponins in non-small cell lung cancer (NSCLC) have not been reported. MATERIALS AND METHODS After treating NSCLC cells by pulsatilla saponin E at different concentrations, cell viability was measured by MTT and CCK-8 assays, and cell migration, invasion and apoptosis were detected by scratch wound-healing, transwell and flow cytometry assays. The contents of free cholesterol (FC) and total cholesterol (TC) were measured by high performance liquid chromatography (HPLC). The expression levels of flotillin-1, flotillin-2, Akt, fatty acid synthase (FASN) were detected by qRT-PCR and Western blot assays. RESULTS Pulsatilla saponin E suppressed viability, migration, invasion and promoted apoptosis of NSCLC cells followed by regulation of apoptosis-related proteins, reduced contents of FC and TC, and the expression levels of flotillin-1, flotillin-2, Akt, and FASN in a concentration-dependent manner. However, the inhibitory effects of pulsatilla saponin E on viability, migration, invasion of A549 cells and the expression levels of flotillin-1, flotillin-2, Akt, and FASN were reversed by flotillin-2 overexpression. CONCLUSIONS Our study revealed that pulsatilla saponin E suppressed migration, invasion and promoted apoptosis of NSCLC cells through negatively regulating Akt/FASN signaling pathway via the inhibition of flotillin-2 in lipid raft (LR). The current findings could be explored for developing a novel therapeutic drug for NSCLC treatment.
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Affiliation(s)
- Minghua Zhu
- Department of Cardiothoracic Surgery, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, PR China
| | - Wei Shi
- Department of Cardiothoracic Surgery, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, PR China
| | - Ke Chen
- Department of Cardiothoracic Surgery, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, PR China
| | - Huiqun Hu
- Department of Cardiothoracic Surgery, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, PR China
| | - Xiangqing Ye
- Department of Cardiothoracic Surgery, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, PR China
| | - Yinfang Jiang
- Department of Cardiovascular Medicine, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
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Flotillins: At the Intersection of Protein S-Palmitoylation and Lipid-Mediated Signaling. Int J Mol Sci 2020; 21:ijms21072283. [PMID: 32225034 PMCID: PMC7177705 DOI: 10.3390/ijms21072283] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 02/07/2023] Open
Abstract
Flotillin-1 and flotillin-2 are ubiquitously expressed, membrane-associated proteins involved in multifarious cellular events from cell signaling, endocytosis, and protein trafficking to gene expression. They also contribute to oncogenic signaling. Flotillins bind the cytosolic leaflet of the plasma membrane and endomembranes and, upon hetero-oligomerization, serve as scaffolds facilitating the assembly of multiprotein complexes at the membrane-cytosol interface. Additional functions unique to flotillin-1 have been discovered recently. The membrane-binding of flotillins is regulated by S-palmitoylation and N-myristoylation, hydrophobic interactions involving specific regions of the polypeptide chain and, to some extent, also by their oligomerization. All these factors endow flotillins with an ability to associate with the sphingolipid/cholesterol-rich plasma membrane domains called rafts. In this review, we focus on the critical input of lipids to the regulation of the flotillin association with rafts and thereby to their functioning. In particular, we discuss how the recent developments in the field of protein S-palmitoylation have contributed to the understanding of flotillin1/2-mediated processes, including endocytosis, and of those dependent exclusively on flotillin-1. We also emphasize that flotillins affect directly or indirectly the cellular levels of lipids involved in diverse signaling cascades, including sphingosine-1-phosphate and PI(4,5)P2. The mutual relations between flotillins and distinct lipids are key to the regulation of their involvement in numerous cellular processes.
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Xu Z, Wang T, Song H, Jiang X. Flotillin-2 predicts poor prognosis and promotes tumor invasion in intrahepatic cholangiocarcinoma. Oncol Lett 2020; 19:2243-2250. [PMID: 32194722 PMCID: PMC7039164 DOI: 10.3892/ol.2020.11349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/14/2020] [Indexed: 12/12/2022] Open
Abstract
Intrahepatic cholangiocarcinoma (iCCA) is a highly malignant neoplasm arising from the intrahepatic bile ducts. As a scaffold protein of lipid rafts, flotillin-2 is upregulated in several types of cancer and promotes tumor progression and metastasis. To the best of our knowledge, the present study was the first to detect the upregulation of flotillin-2 in iCCA tissues compared with matched adjacent non-tumor tissues. In addition, immunohistochemistry was used to investigate the expression of flotillin-2 in a microarray consisting of 92 iCCA tissues. A total of 59 samples (64.1%) exhibited high flotillin-2 expression, which was significantly related to lymph node metastasis (P=0.029) and tumor-node-metastasis stage (P=0.016). Further in vitro study demonstrated that knockdown of flotillin-2 inhibited the invasive capability of iCCA cell lines, further supporting the participation of flotillin-2 in cancer invasion and metastasis. Moreover, Kaplan-Meier analysis showed patients with high flotillin-2 expression had worse overall survival outcomes. The multivariate Cox proportional hazards model further revealed that high flotillin-2 expression was an independent indicator (P=0.005) of poor prognosis for patients with iCCA. Collectively, the present study revealed that as a promoter of invasion and an independent marker of poor prognosis, flotillin-2 may serve as a potential target for the development of novel therapeutic agents for iCCA.
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Affiliation(s)
- Zhiying Xu
- Department of Nuclear Medicine, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong 264001, P.R. China
| | - Tao Wang
- Department of Interventional Therapy, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong 264001, P.R. China
| | - Haiyang Song
- Department of Interventional Therapy, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong 264001, P.R. China
| | - Xuewen Jiang
- Department of Nuclear Medicine, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong 264001, P.R. China
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Increase in fatty acids and flotillins upon resveratrol treatment of human breast cancer cells. Sci Rep 2019; 9:13960. [PMID: 31562347 PMCID: PMC6764983 DOI: 10.1038/s41598-019-50416-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/06/2019] [Indexed: 12/11/2022] Open
Abstract
Flotillin-1 and flotillin-2 are highly conserved proteins that localize into cholesterol-rich microdomains in cellular membranes. Flotillins are closely related to the occurrence and development of various types of human cancers. Flotillin-1 is highly expressed in breast cancer, and the high expression level of flotillin-1 is significantly correlated with poorer patient survival. Here we studied the relationship between the formation of lipid rafts and the expression of flotillins and lipids in human breast cancer cells. We used the polyphenol compound resveratrol to alter the structure and function of the plasma membrane. Our data revealed an increase in fatty acids in MCF-7 and MDA-MB-231 cells upon resveratrol treatment. Interestingly, we also found an increase in the expression of both flotillin-1 and flotillin-2 in breast tumor cells after treatment. Resveratrol also induced changes in the pattern of flotillin distribution among detergent-resistant lipid rafts fractions in both cell lines and induced the nuclear translocation of flotillin-2. Since resveratrol has been pointed out as a putative cancer therapy agent, our results could have an impact on the understanding of the effects of resveratrol in tumor cells.
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11
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Chen SH, Liu XN, Peng Y. MicroRNA-351 eases insulin resistance and liver gluconeogenesis via the PI3K/AKT pathway by inhibiting FLOT2 in mice of gestational diabetes mellitus. J Cell Mol Med 2019; 23:5895-5906. [PMID: 31287224 PMCID: PMC6714143 DOI: 10.1111/jcmm.14079] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/10/2018] [Accepted: 11/13/2018] [Indexed: 12/29/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is known as different degree glucose intolerance that is initially identified during pregnancy. MicroRNAs (miRs) may be a potential candidate for treatment of GDM. Herein, we suggested that miR‐351 could be an inhibitor in the progression of GDM via the phosphoinositide 3‐kinase/protein kinase B (PI3K/AKT) pathway. Microarray analysis was used to identify differentially expressed genes and predict miRs regulating flotillin 2 (FLOT2). Target relationship between miR‐351 and FLOT2 was verified. Gestational diabetes mellitus mice were treated with a series of mimic, inhibitor and small interfering RNA to explore the effect of miR‐351 on insulin resistance (IR), cell apoptosis in pancreatic tissues and liver gluconeogenesis through evaluating GDM‐related biochemical indexes, as well as expression of miR‐351, FLOT2, PI3K/AKT pathway‐, IR‐ and liver gluconeogenesis‐related genes. MiR‐351 and FLOT2 were reported to be involved in GDM. FLOT2 was the target gene of miR‐351. Gestational diabetes mellitus mice exhibited IR and liver gluconeogenesis, up‐regulated FLOT2, activated PI3K/AKT pathway and down‐regulated miR‐351 in liver tissues. Additionally, miR‐351 overexpression and FLOT2 silencing decreased the levels of FLOT2, phosphoenolpyruvate carboxykinase, glucose‐6‐phosphatase, fasting blood glucose, fasting insulin, total cholesterol, triglyceride, glyeosylated haemoglobin and homeostasis model of assessment for IR index (HOMA‐IR), extent of PI3K and AKT phosphorylation, yet increased the levels of HOMA for islet β‐cell function, HOMA for insulin sensitivity index and glucose transporter 2 expression, indicating reduced cell apoptosis in pancreatic tissues and alleviated IR and liver gluconeogenesis. Our results reveal that up‐regulation of miR‐351 protects against IR and liver gluconeogenesis by repressing the PI3K/AKT pathway through regulating FLOT2 in GDM mice, which identifies miR‐351 as a potential therapeutic target for the clinical management of GDM.
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Affiliation(s)
- Shu-Hong Chen
- Department of Endocrinology, Linyi People's Hospital, Linyi, Shandong Province, P.R. China
| | - Xiao-Nan Liu
- Department of Endocrinology, Linyi People's Hospital, Linyi, Shandong Province, P.R. China
| | - Yan Peng
- Department of Endocrinology, Linyi People's Hospital, Linyi, Shandong Province, P.R. China
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Huang S, Zheng S, Huang S, Cheng H, Lin Y, Wen Y, Lin W. Flot2 targeted by miR-449 acts as a prognostic biomarker in glioma. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2019; 47:250-255. [PMID: 30663389 DOI: 10.1080/21691401.2018.1549062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Shaosong Huang
- Department of Neurosurgery, Fujian Provincial Hospital of Fujian Medical University, Fuzhou, China
| | - Shihao Zheng
- Department of Neurosurgery, Fujian Provincial Hospital of Fujian Medical University, Fuzhou, China
| | - Shengyue Huang
- Department of Neurosurgery, Fujian Provincial Hospital of Fujian Medical University, Fuzhou, China
| | - Hui Cheng
- Department of Pathology, Fujian Provincial Hospital of Fujian Medical University, Fuzhou, China
| | - Ying Lin
- Department of Pathology, Fujian Provincial Hospital of Fujian Medical University, Fuzhou, China
| | - Yuxing Wen
- Department of Neurosurgery, Fujian Provincial Hospital of Fujian Medical University, Fuzhou, China
| | - Wei Lin
- Department of Neurosurgery, Fujian Provincial Hospital of Fujian Medical University, Fuzhou, China
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Liu XX, Liu WD, Wang L, Zhu B, Shi X, Peng ZX, Zhu HC, Liu XD, Zhong MZ, Xie D, Zeng MS, Ren CP. Roles of flotillins in tumors. J Zhejiang Univ Sci B 2018; 19:171-182. [PMID: 29504311 DOI: 10.1631/jzus.b1700102] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The identification and use of molecular biomarkers have greatly improved the diagnosis and treatment of malignant tumors. However, a much deeper understanding of oncogenic proteins is needed for the benefit to cancer patients. The lipid raft marker proteins, flotillin-1 and flotillin-2, were first found in goldfish retinal ganglion cells during axon regeneration. They have since been found in a variety of cells, mainly on the inner surface of cell membranes, and not only act as a skeleton to provide a platform for protein-protein interactions, but also are involved in signal transduction, nerve regeneration, endocytosis, and lymphocyte activation. Previous studies have shown that flotillins are closely associated with tumor development, invasion, and metastasis. In this article, we review the functions of flotillins in relevant cell processes, their underlying mechanisms of action in a variety of tumors, and their potential applications to tumor molecular diagnosis and targeted therapy.
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Affiliation(s)
- Xu-Xu Liu
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Central South University, Changsha 410078, China
| | - Wei-Dong Liu
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Central South University, Changsha 410078, China
| | - Lei Wang
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Central South University, Changsha 410078, China
| | - Bin Zhu
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Central South University, Changsha 410078, China
| | - Xiao Shi
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Central South University, Changsha 410078, China
| | - Zi-Xuan Peng
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Central South University, Changsha 410078, China
| | - He-Cheng Zhu
- Changsha Kexin Cancer Hospital, Changsha 410205, China
| | - Xing-Dong Liu
- Changsha Kexin Cancer Hospital, Changsha 410205, China
| | - Mei-Zuo Zhong
- Changsha Kexin Cancer Hospital, Changsha 410205, China
| | - Dan Xie
- State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Mu-Sheng Zeng
- State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Cai-Ping Ren
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Central South University, Changsha 410078, China
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14
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Curcumin Induces p53-Null Hepatoma Cell Line Hep3B Apoptosis through the AKT-PTEN-FOXO4 Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 2017:4063865. [PMID: 28769986 PMCID: PMC5523542 DOI: 10.1155/2017/4063865] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 06/06/2017] [Indexed: 12/19/2022]
Abstract
Objective Curcumin (diferuloylmethane) is a yellow-colored polyphenol with antiproliferative and proapoptotic activities to various types of cancer cells. This study explored the mechanism by which curcumin induces p53-null hepatoma cell apoptosis. Results AKT, FOXO1, and FOXO3 proteins were downregulated after curcumin treatment. Conversely, PTEN was upregulated. Subcellular fractionations revealed that the FOXO4 protein translocated from cytosol into the nucleus after curcumin treatment. Overexpression of FOXO4 increases the sensitivity of Hep3B cells to curcumin. Knockdown of the FOXO4 gene by siRNA inhibits the proapoptotic effects of curcumin on Hep3B cell. Conclusions This study revealed the AKT/PTEN/FOXO4 pathway as a potential candidate of target for treatment of p53-null liver cancers.
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Wei G, Xu Y, Peng T, Yan J. miR-133 involves in lung adenocarcinoma cell metastasis by targeting FLOT2. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2017; 46:224-230. [PMID: 28503944 DOI: 10.1080/21691401.2017.1324467] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Dysregulated microRNAs (miRNAs) reported to involve into the oncogenesis and progression in various human cancers. However, the roles and mechanism of miR-133 in lung adenocarcinoma remain largely unclear. METHODS In this study, qPCR assay and western blot were used to detect the expression levels of miR-133, Akt and FLOT2. Luciferase reporter assay was used to identify the target role of miR-133 on FLOT2. The cell invasion and the migration capability were performed using the transwell invasion assay and wound healing assay. RESULTS We found that miR-133 expression levels were downregulated in human lung adenocarcinoma specimens and cell lines compared with the adjacent normal tissues and normal human bronchial epithelial cell. miR-133 significantly suppressed metastasis of lung adenocarcinoma cells in vitro. Furthermore, FLOT2 (flotillin-2) identified as a direct target of miR-133, and FLOT2 expression levels were inversely correlated with miR-133 expression levels in human lung adenocarcinoma specimens. And the restoration studies suggested FGF2 as a downstream effector of miR-133 which acted through Akt signalling pathway. CONCLUSIONS Our study revealed the mechanism that miR-133 suppresses lung adenocarcinoma metastasis by targeting FLOT2 via Akt signalling pathway, implicating a potential prognostic biomarker and therapeutic target for lung adenocarcinoma treatment.
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Affiliation(s)
- Guangxia Wei
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
| | - Yahuan Xu
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
| | - Tao Peng
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
| | - Jie Yan
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
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MiR-485 inhibits metastasis and EMT of lung adenocarcinoma by targeting Flot2. Biochem Biophys Res Commun 2016; 477:521-526. [DOI: 10.1016/j.bbrc.2016.04.043] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/09/2016] [Indexed: 01/24/2023]
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17
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MiR-572 prompted cell proliferation of human ovarian cancer cells by suppressing PPP2R2C expression. Biomed Pharmacother 2015; 77:92-7. [PMID: 26796271 DOI: 10.1016/j.biopha.2015.12.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 12/08/2015] [Accepted: 12/11/2015] [Indexed: 12/31/2022] Open
Abstract
Ovarian cancer (OC) remains one of the most common types of malignant cancer, and the molecular mechanism underlying its proliferation is still largely unclear. It is reported that microRNAs acted as important regulators of cell proliferation by regulating its targeted gene. In this study, our result showed that miR-572 was markedly upregulated in OC cell lines and clinical tissues. Results of both gain-of-function and loss-of-function experiments revealed that upregulation of miR-572 expression dramatically promoted OC cell proliferation, whereas decreased miR-572 expression significantly reduced cell proliferation. Bioinformatics analysis and luciferase reporter assays further revealed PPP2R2C, a putative tumor suppressor as a potential target of miR-572. Moreover, silencing of PPP2R2C using small interfering RNA (siRNA) counteracted the proliferation arrest by miR-572-in in OC cells. In sum, our data provide that miR-572 promoted cell proliferation in OC by targeting PPP2R2C and might serve as a therapeutic target of OC.
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18
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Liang WL, Cao J, Xu B, Yang P, Shen F, Sun Z, Li WL, Wang Q, Liu F. miR-892a regulated PPP2R2A expression and promoted cell proliferation of human colorectal cancer cells. Biomed Pharmacother 2015; 72:119-24. [DOI: 10.1016/j.biopha.2015.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 04/14/2015] [Indexed: 01/16/2023] Open
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