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Pu M, Zheng W, Zhang H, Wan W, Peng C, Chen X, Liu X, Xu Z, Zhou T, Sun Q, Neculai D, Liu W. ORP8 acts as a lipophagy receptor to mediate lipid droplet turnover. Protein Cell 2023; 14:653-667. [PMID: 37707322 PMCID: PMC10501187 DOI: 10.1093/procel/pwac063] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/22/2022] [Indexed: 09/15/2023] Open
Abstract
Lipophagy, the selective engulfment of lipid droplets (LDs) by autophagosomes for lysosomal degradation, is critical to lipid and energy homeostasis. Here we show that the lipid transfer protein ORP8 is located on LDs and mediates the encapsulation of LDs by autophagosomal membranes. This function of ORP8 is independent of its lipid transporter activity and is achieved through direct interaction with phagophore-anchored LC3/GABARAPs. Upon lipophagy induction, ORP8 has increased localization on LDs and is phosphorylated by AMPK, thereby enhancing its affinity for LC3/GABARAPs. Deletion of ORP8 or interruption of ORP8-LC3/GABARAP interaction results in accumulation of LDs and increased intracellular triglyceride. Overexpression of ORP8 alleviates LD and triglyceride deposition in the liver of ob/ob mice, and Osbpl8-/- mice exhibit liver lipid clearance defects. Our results suggest that ORP8 is a lipophagy receptor that plays a key role in cellular lipid metabolism.
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Affiliation(s)
- Maomao Pu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Wenhui Zheng
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Hongtao Zhang
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Wei Wan
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Chao Peng
- National Center for Protein Science Shanghai, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xuebo Chen
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Xinchang Liu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Zizhen Xu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Tianhua Zhou
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Qiming Sun
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Dante Neculai
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Wei Liu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
- Joint Institute of Genetics and Genomics Medicine between Zhejiang University and University of Toronto, Hangzhou 310058, China
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Eisenreichova A, Klima M, Anila MM, Koukalova A, Humpolickova J, Różycki B, Boura E. Crystal Structure of the ORP8 Lipid Transport ORD Domain: Model of Lipid Transport. Cells 2023; 12:1974. [PMID: 37566053 PMCID: PMC10417380 DOI: 10.3390/cells12151974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/12/2023] Open
Abstract
ORPs are lipid-transport proteins belonging to the oxysterol-binding protein family. They facilitate the transfer of lipids between different intracellular membranes, such as the ER and plasma membrane. We have solved the crystal structure of the ORP8 lipid transport domain (ORD8). The ORD8 exhibited a β-barrel fold composed of anti-parallel β-strands, with three α-helices replacing β-strands on one side. This mixed alpha-beta structure was consistent with previously solved structures of ORP2 and ORP3. A large cavity (≈1860 Å3) within the barrel was identified as the lipid-binding site. Although we were not able to obtain a lipid-bound structure, we used computer simulations based on our crystal structure to dock PS and PI4P molecules into the putative lipid-binding site of the ORD8. Comparative experiments between the short ORD8ΔLid (used for crystallography) and the full-length ORD8 (lid containing) revealed the lid's importance for stable lipid binding. Fluorescence assays revealed different transport efficiencies for PS and PI4P, with the lid slowing down transport and stabilizing cargo. Coarse-grained simulations highlighted surface-exposed regions and hydrophobic interactions facilitating lipid bilayer insertion. These findings enhance our comprehension of ORD8, its structure, and lipid transport mechanisms, as well as provide a structural basis for the design of potential inhibitors.
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Affiliation(s)
- Andrea Eisenreichova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Martin Klima
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Midhun Mohan Anila
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland; (M.M.A.); (B.R.)
| | - Alena Koukalova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Jana Humpolickova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland; (M.M.A.); (B.R.)
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
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Zhang L, Pan Q, Wu Y, Zhang P, Li S, Xu Y, Li D, Zheng M, Pei D, Wang Q. ORP8 inhibits renal cell carcinoma progression by accelerating Stathmin1 degradation and microtubule polymerization. Exp Cell Res 2023; 427:113601. [PMID: 37054771 DOI: 10.1016/j.yexcr.2023.113601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 04/15/2023]
Abstract
ORP8 has been reported to suppress tumor progression in various malignancies. However, the functions and underlying mechanisms of ORP8 are still unknown in renal cell carcinoma (RCC). Here, decreased expression of ORP8 was detected in RCC tissues and cell lines. Functional assays verified that ORP8 suppressed RCC cell growth, migration, invasion, and metastasis. Mechanistically, ORP8 attenuated Stathmin1 expression by accelerating ubiquitin-mediated proteasomal degradation and led to an increase in microtubule polymerization. Lastly, ORP8 knockdown partly rescued microtubule polymerization, as well as aggressive cell phenotypes induced by paclitaxel. Our findings elucidated that ORP8 suppressed the malignant progression of RCC by increasing Stathmin1 degradation and microtubule polymerization, thus suggesting that ORP8 might be a novel target for the treatment of RCC.
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Affiliation(s)
- Lin Zhang
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China
| | - Qiwei Pan
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China; Taizhou Hospital of Zhejiang, Taizhou, 317000, Zhejiang, China
| | - Yi Wu
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China
| | - Peng Zhang
- Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China
| | - Shibao Li
- Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Yuting Xu
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China
| | - Danhua Li
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China
| | - Maojin Zheng
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China
| | - Dongsheng Pei
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China.
| | - Qingling Wang
- Department of Pathology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, China.
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Kattan WE, Liu J, Montufar-Solis D, Liang H, Brahmendra Barathi B, van der Hoeven R, Zhou Y, Hancock JF. Components of the phosphatidylserine endoplasmic reticulum to plasma membrane transport mechanism as targets for KRAS inhibition in pancreatic cancer. Proc Natl Acad Sci U S A 2021; 118:e2114126118. [PMID: 34903667 DOI: 10.1073/pnas.2114126118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2021] [Indexed: 12/19/2022] Open
Abstract
KRAS is mutated in 90% of human pancreatic ductal adenocarcinomas (PDACs). To function, KRAS must localize to the plasma membrane (PM) via a C-terminal membrane anchor that specifically engages phosphatidylserine (PtdSer). This anchor-binding specificity renders KRAS-PM localization and signaling capacity critically dependent on PM PtdSer content. We now show that the PtdSer lipid transport proteins, ORP5 and ORP8, which are essential for maintaining PM PtdSer levels and hence KRAS PM localization, are required for KRAS oncogenesis. Knockdown of either protein, separately or simultaneously, abrogated growth of KRAS-mutant but not KRAS-wild-type pancreatic cancer cell xenografts. ORP5 or ORP8 knockout also abrogated tumor growth in an immune-competent orthotopic pancreatic cancer mouse model. Analysis of human datasets revealed that all components of this PtdSer transport mechanism, including the PM-localized EFR3A-PI4KIIIα complex that generates phosphatidylinositol-4-phosphate (PI4P), and endoplasmic reticulum (ER)-localized SAC1 phosphatase that hydrolyzes counter transported PI4P, are significantly up-regulated in pancreatic tumors compared to normal tissue. Taken together, these results support targeting PI4KIIIα in KRAS-mutant cancers to deplete the PM-to-ER PI4P gradient, reducing PM PtdSer content. We therefore repurposed the US Food and Drug Administration-approved hepatitis C antiviral agent, simeprevir, as a PI4KIIIα inhibitor In a PDAC setting. Simeprevir potently mislocalized KRAS from the PM, reduced the clonogenic potential of pancreatic cancer cell lines in vitro, and abrogated the growth of KRAS-dependent tumors in vivo with enhanced efficacy when combined with MAPK and PI3K inhibitors. We conclude that the cellular ER-to-PM PtdSer transport mechanism is essential for KRAS PM localization and oncogenesis and is accessible to therapeutic intervention.
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Abstract
MiR-143 is an miRNA with the function of specifically inhibiting the insulin-AKT pathway via the downregulation of oxysterol-binding protein-related protein 8 (ORP8), thus resulting in the inhibition of AKT phosphorylation, insulin tolerance, and final development of type II diabetes mellitus (T2DM). Aerobic exercise can prevent T2DM by downregulating miR-143. However, the underlying mechanisms for exercise-induced change of miR-143 remain unclear. In the present study, we will summarize the involvement of miR-143 in regulating the development of T2DM and the underlying mechanisms for potential diagnosis, prevention, and treatments, including exercise intervention for T2DM by targeting miR-143.
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Affiliation(s)
- Biao Li
- Graduate School, Wuhan Sports University, Wuhan 430079, China; These authors contributed equally to this work
| | - Jingjing Fan
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Sport Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan 430079, China; These authors contributed equally to this work
| | - Ning Chen
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Sport Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan 430079, China.
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Pulli I, Lassila T, Pan G, Yan D, Olkkonen VM, Törnquist K. Oxysterol-binding protein related-proteins (ORPs) 5 and 8 regulate calcium signaling at specific cell compartments. Cell Calcium 2018; 72:62-69. [PMID: 29748134 DOI: 10.1016/j.ceca.2018.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/02/2018] [Accepted: 03/12/2018] [Indexed: 12/24/2022]
Abstract
Oxysterol-binding protein related-protein 5 and 8 (ORP5/8) localize to the membrane contact sites (MCS) of the endoplasmic reticulum (ER) and the mitochondria, as well as to the ER-plasma membrane (PM) MCS. The MCS are emerging as important regulators of cell signaling events, including calcium (Ca2+) signaling. ORP5/8 have been shown to interact with phosphatidylinositol-4,5-bisphosphate (PIP2) in the PM, and to modulate mitochondrial respiration and morphology. PIP2 is the direct precursor of inositol trisphosphate (IP3), a key second messenger responsible for Ca2+-release from the intracellular Ca2+ stores. Further, mitochondrial respiration is linked to Ca2+ transfer from the ER to the mitochondria. Hence, we asked whether ORP5/8 would affect Ca2+ signaling in these cell compartments, and employed genetically engineered aequorin Ca2+ probes to investigate the effect of ORP5/8 in the regulation of mitochondrial and caveolar Ca2+. Our results show that ORP5/8 overexpression leads to increased mitochondrial matrix Ca2+ as well as to increased Ca2+ concentration at the caveolar subdomains of the PM during histamine stimulation, while having no effect on the cytoplasmic Ca2+. Also, we found that ORP5/8 overexpression increases cell proliferation. Our results show that ORP5/8 regulate Ca2+ signaling at specific MCS foci. These local ORP5/8-mediated Ca2+ signaling events are likely to play roles in processes such as mitochondrial respiration and cell proliferation.
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Affiliation(s)
- Ilari Pulli
- Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Taru Lassila
- Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Guoping Pan
- The Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China
| | - Daoguang Yan
- The Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China
| | - Vesa M Olkkonen
- Minerva Foundation Institute For Medical Research, Biomedicum Helsinki, 00290 Helsinki, Finland; Department of Anatomy, Faculty of Medicine, FI-00014 University of Helsinki, Finland
| | - Kid Törnquist
- Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland; Minerva Foundation Institute For Medical Research, Biomedicum Helsinki, 00290 Helsinki, Finland.
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Du X, Zadoorian A, Lukmantara IE, Qi Y, Brown AJ, Yang H. Oxysterol-binding protein-related protein 5 (ORP5) promotes cell proliferation by activation of mTORC1 signaling. J Biol Chem 2018; 293:3806-3818. [PMID: 29358326 DOI: 10.1074/jbc.ra117.001558] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/18/2018] [Indexed: 01/29/2023] Open
Abstract
Oxysterol-binding protein (OSBP) and OSBP-related proteins (ORPs) constitute a large family of proteins that mainly function in lipid transport and sensing. ORP5 is an endoplasmic reticulum (ER)-anchored protein implicated in lipid transfer at the contact sites between the ER and other membranes. Recent studies indicate that ORP5 is also involved in cancer cell invasion and tumor progression. However, the molecular mechanism underlying ORP5's involvement in cancer is unclear. Here, we report that ORP5 promotes cell proliferation and motility of HeLa cells, an effect that depends on its functional OSBP-related domain (ORD). We also found that ORP5 depletion or substitutions of key residues located within ORP5-ORD and responsible for interactions with lipids interfered with cell proliferation, migration, and invasion. ORP5 interacted with the protein mechanistic target of rapamycin (mTOR), and this interaction also required ORP5-ORD. Of note, whereas ORP5 overexpression induced mTOR complex 1 (mTORC1) activity, ORP5 down-regulation had the opposite effect. Finally, ORP5-depleted cells exhibited impaired mTOR localization to lysosomes, which may have accounted for the blunted mTORC1 activation. Together, our results suggest that ORP5 expression is positively correlated with mTORC1 signaling and that ORP5 stimulates cell proliferation, at least in part, by activating mTORC1.
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Affiliation(s)
- Ximing Du
- From the School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Armella Zadoorian
- From the School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Ivan E Lukmantara
- From the School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yanfei Qi
- From the School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Andrew J Brown
- From the School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Hongyuan Yang
- From the School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
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Du X, Turner N, Yang H. The role of oxysterol-binding protein and its related proteins in cancer. Semin Cell Dev Biol 2018; 81:149-53. [PMID: 28733164 DOI: 10.1016/j.semcdb.2017.07.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/28/2017] [Accepted: 07/14/2017] [Indexed: 01/17/2023]
Abstract
Oxysterol-binding protein (OSBP) and its related proteins (ORPs) constitute a large, evolutionarily conserved family of lipid-binding proteins that are associated with a wide range of cellular activities. The core function of OSBP/ORPs appears to be moving lipids between cellular membranes in a non-vesicular manner. Recent studies have unveiled a novel, counter-transport mechanism of cellular lipid transfer mediated by OSBP/ORPs at the membrane contact sites that involves phosphatidylinositol 4-phosphate. Importantly, the OSBP/ORPs family has also been implicated in cell signalling pathways and cancer development. Here, we summarize recent progress in understanding the role of OSBP/ORPs in cancer development, and discuss how the lipid transfer function of OSBP/ORPs may underpin their role in tumorigenesis.
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Zhong W, Qin S, Zhu B, Pu M, Liu F, Wang L, Ye G, Yi Q, Yan D. Oxysterol-binding protein-related protein 8 ( ORP8) increases sensitivity of hepatocellular carcinoma cells to Fas-mediated apoptosis. J Biol Chem 2015; 290:8876-87. [PMID: 25596532 DOI: 10.1074/jbc.m114.610188] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Indexed: 12/16/2022] Open
Abstract
Human hepatoma (HCC) has been reported to be strongly resistant to Fas-mediated apoptosis. However, the underlying mechanisms are poorly understood. In this study the function of oxysterol-binding protein-related protein 8 (ORP8) in human hepatoma cells apoptosis was assessed. We found that ORP8 is down-regulated, whereas miR-143, which controls ORP8 expression, is up-regulated in clinical HCC tissues as compared with liver tissue from healthy subjects. ORP8 overexpression triggered apoptosis in primary HCC cells and cell lines, which coincided with a relocation of cytoplasmic Fas to the cell plasma membrane and FasL up-regulation. Co-culture of HepG2 cells or primary HCC cells with Jurkat T-cells or T-cells, respectively, provided further evidence that ORP8 increases HCC cell sensitivity to Fas-mediated apoptosis. ORP8-induced Fas translocation is p53-dependent, and FasL was induced upon ORP8 overexpression via the endoplasmic reticulum stress response. Moreover, ORP8 overexpression and miR-143 inhibition markedly inhibited tumor growth in a HepG2 cell xenograft model. These results indicate that ORP8 induces HCC cell apoptosis through the Fas/FasL pathway. The role of ORP8 in Fas translocation to the plasma membrane and its down-regulation by miR-143 offer a putative mechanistic explanation for HCC resistance to apoptosis. ORP8 may be a potential target for HCC therapy.
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Affiliation(s)
- Wenbin Zhong
- From the Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and Department of Biotechnology, Jinan University, Guangzhou, 510632, China
| | - Shengying Qin
- From the Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and Department of Biotechnology, Jinan University, Guangzhou, 510632, China
| | - Biying Zhu
- From the Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and Department of Biotechnology, Jinan University, Guangzhou, 510632, China
| | - Miaoshui Pu
- Department of Hepatobiliary Surgery, Guangzhou General Hospital, Guangzhou 510010, China, and
| | - Fupei Liu
- From the Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and Department of Biotechnology, Jinan University, Guangzhou, 510632, China
| | - Lin Wang
- From the Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and Department of Biotechnology, Jinan University, Guangzhou, 510632, China
| | - Guilin Ye
- From the Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and Department of Biotechnology, Jinan University, Guangzhou, 510632, China
| | - Qing Yi
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Daoguang Yan
- From the Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and Department of Biotechnology, Jinan University, Guangzhou, 510632, China,
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Zhong W, Zhou Y, Li J, Mysore R, Luo W, Li S, Chang MS, Olkkonen VM, Yan D. OSBP-related protein 8 ( ORP8) interacts with Homo sapiens sperm associated antigen 5 (SPAG5) and mediates oxysterol interference of HepG2 cell cycle. Exp Cell Res 2014; 322:227-35. [PMID: 24424245 DOI: 10.1016/j.yexcr.2014.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 12/19/2013] [Accepted: 01/03/2014] [Indexed: 02/02/2023]
Abstract
We earlier identified OSBP-related protein 8 (ORP8) as an endoplasmic reticulum/nuclear envelope oxysterol-binding protein implicated in cellular lipid homeostasis, migration, and organization of the microtubule cytoskeleton. Here, a yeast two-hybrid screen identified Homo sapiens sperm associated antigen 5 (SPAG5)/Astrin as interaction partner of ORP8. The putative interaction was further confirmed by pull-down and co-immunoprecipitation assays. ORP8 did not colocalize with kinetochore-associated SPAG5 in mitotic HepG2 or HuH7 cells, but overexpressed ORP8 was capable of recruiting SPAG5 onto endoplasmic reticulum membranes in interphase cells. In our experiments, 25-hydroxycholesterol (25OHC) retarded the HepG2 cell cycle, causing accumulation in G2/M phase; ORP8 overexpression resulted in the same phenotype. Importantly, ORP8 knock-down dramatically inhibited the oxysterol effect on HepG2 cell cycle, suggesting a mediating role of ORP8. Furthermore, knock-down of SPAG5 significantly reduced the effects of both ORP8 overexpression and 25OHC on the cell cycle, placing SPAG5 downstream of the two cell-cycle interfering factors. Taken together, the present results suggest that ORP8 may via SPAG5 mediate oxysterol interference of the HepG2 cell cycle.
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Affiliation(s)
- Wenbin Zhong
- Department of Biotechnology, Jinan University, Guangzhou 510632, China
| | - You Zhou
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Jiwei Li
- Department of Biotechnology, Jinan University, Guangzhou 510632, China
| | | | - Wei Luo
- Department of Biotechnology, Jinan University, Guangzhou 510632, China
| | - Shiqian Li
- Department of Biotechnology, Jinan University, Guangzhou 510632, China
| | - Mau-Sun Chang
- Institute of Biochemical Sciences, National Taiwan University, No. 1, Taipei, Taiwan
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Daoguang Yan
- Department of Biotechnology, Jinan University, Guangzhou 510632, China.
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