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De Florian Fania R, Bellazzo A, Collavin L. An update on the tumor-suppressive functions of the RasGAP protein DAB2IP with focus on therapeutic implications. Cell Death Differ 2024:10.1038/s41418-024-01332-3. [PMID: 38902547 DOI: 10.1038/s41418-024-01332-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 06/22/2024] Open
Abstract
The dynamic crosstalk between tumor and stromal cells is a major determinant of cancer aggressiveness. The tumor-suppressor DAB2IP (Disabled homolog 2 interacting protein) plays an important role in this context, since it modulates cell responses to multiple extracellular inputs, including inflammatory cytokines and growth factors. DAB2IP is a RasGAP and negatively controls Ras-dependent mitogenic signals. In addition, it modulates other major oncogenic pathways, including TNFα/NF-κB, WNT/β-catenin, PI3K/AKT, and androgen receptor signaling. In line with its tumor-suppressive role, DAB2IP is frequently inactivated in cancer by transcriptional and post-transcriptional mechanisms, including promoter methylation, microRNA-mediated downregulation, and protein-protein interactions. Intriguingly, some observations suggest that downregulation of DAB2IP in cells of the tumor stroma could foster establishment of a pro-metastatic microenvironment. This review summarizes recent insights into the tumor-suppressive functions of DAB2IP and the consequences of its inactivation in cancer. In particular, we explore potential approaches aimed at reactivating DAB2IP, or augmenting its expression levels, as a novel strategy in cancer treatment. We suggest that reactivation or upregulation of DAB2IP would concurrently attenuate multiple oncogenic pathways in both cancer cells and the tumor microenvironment, with implications for improved treatment of a broad spectrum of tumors.
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Affiliation(s)
| | - Arianna Bellazzo
- Unit of Immunopathology and Cancer Biomarkers, Centro di Riferimento Oncologico di Aviano (CRO), IRCCS, Via Franco Gallini, 2, 33081, Aviano, Italy
| | - Licio Collavin
- Department of Life Sciences, University of Trieste, Via L. Giorgieri 1, 34127, Trieste, Italy.
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Bonnici L, Suleiman S, Schembri-Wismayer P, Cassar A. Targeting Signalling Pathways in Chronic Wound Healing. Int J Mol Sci 2023; 25:50. [PMID: 38203220 PMCID: PMC10779022 DOI: 10.3390/ijms25010050] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/11/2023] [Accepted: 12/15/2023] [Indexed: 01/12/2024] Open
Abstract
Chronic wounds fail to achieve complete closure and are an economic burden to healthcare systems due to the limited treatment options and constant medical attention. Chronic wounds are characterised by dysregulated signalling pathways. Research has focused on naturally derived compounds, stem-cell-based therapy, small molecule drugs, oligonucleotide delivery nanoparticles, exosomes and peptide-based platforms. The phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT), Wingless-related integration (Wnt)/β-catenin, transforming growth factor-β (TGF-β), nuclear factor erythroid 2-related factor 2 (Nrf2), Notch and hypoxia-inducible factor 1 (HIF-1) signalling pathways have critical roles in wound healing by modulating the inflammatory, proliferative and remodelling phases. Moreover, several regulators of the signalling pathways were demonstrated to be potential treatment targets. In this review, the current research on targeting signalling pathways under chronic wound conditions will be discussed together with implications for future studies.
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Affiliation(s)
| | | | | | - Analisse Cassar
- Department of Anatomy, University of Malta, MSD 2080 Msida, Malta; (L.B.); (S.S.); (P.S.-W.)
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Liang A, Liu J, Wei Y, Liao Y, Wu F, Ruan J, Li J. m 6A reader IGF2BP1 accelerates apoptosis of high glucose-induced vascular endothelial cells in a m 6A-HMGB1 dependent manner. PeerJ 2023; 11:e14954. [PMID: 37009154 PMCID: PMC10062336 DOI: 10.7717/peerj.14954] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/03/2023] [Indexed: 03/29/2023] Open
Abstract
Emerging evidence indicates that N6-methyladenosine (m6A) plays a critical role in vascular biological characteristic. In diabetes mellitus pathophysiology, high glucose (HG)-induced vascular endothelial dysfunction is associated with diabetes vascular complications. Nevertheless, the underlying mechanism of high glucose (HG)-related m6A regulation on vascular endothelial cells is still unclear. Results indicated that m6A reader insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) was up-regulated in HG-treated human umbilical vascular endothelium cells (HUVECs) comparing to normal group. Functionally, results indicated that IGF2BP1 knockdown recovered the proliferation of HUVECs inhibited by HG-administration. Besides, IGF2BP1 knockdown reduced the apoptosis induced by HG-administration. Mechanistically, IGF2BP1 interacted with HMGB1 mRNA and stabilized its expression of m6A-modified RNA. Therefore, these findings provided compelling evidence demonstrating that m6A reader IGF2BP1 contributes to the proliferation and apoptosis of vascular endothelial cells in hyperglycaemia, serving as a target for development of diabetic angiopathy therapeutics.
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Affiliation(s)
- Anru Liang
- Department of Burns and Plastic Surgery, The Third Affiliated Hospital of Guangxi Medical University and The Second People’s Hospital of Nanning, Nanning, China
| | - Jianyu Liu
- Department of Clinical Laboratory, Guiping People’s Hospital, Guigping, China
| | - Yanlin Wei
- Department of Emergency, The People’s Hospital of Guangxi Zhuang Autonomous Region & Guangxi Academy of Medical Sciences, Nanning, China
| | - Yuan Liao
- Department of Clinical Laboratory, Guiping People’s Hospital, Guigping, China
| | - Fangxiao Wu
- Department of Burns and Plastic Surgery, The Third Affiliated Hospital of Guangxi Medical University and The Second People’s Hospital of Nanning, Nanning, China
| | - Jiang Ruan
- Department of Burns and Plastic Surgery, The Third Affiliated Hospital of Guangxi Medical University and The Second People’s Hospital of Nanning, Nanning, China
| | - Junjun Li
- Research Center of Medical Sciences, The People’s Hospital of Guangxi Zhuang Autonomous Region & Guangxi Academy of Medical Sciences, Nanning, China
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Song Z, Chen C, He J, Liu B, Ji W, Wu L, He L. ASK1-Interacting Protein 1 Acts as a Novel Predictor of Type 2 Diabetes. Front Endocrinol (Lausanne) 2022; 13:896753. [PMID: 35712257 PMCID: PMC9196954 DOI: 10.3389/fendo.2022.896753] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Type 2 diabetes (T2D) mellitus is a chronic inflammatory disease characterized with high secretion of tumor necrosis factor (TNF)-α, but the regulatory pathway of TNF-α production in T2D has not been fully elucidated. ASK1-interacting protein 1 (AIP1) is a signaling scaffold protein that modulates several pathways associated with inflammation. In this study, we aimed to investigate the role of AIP1 in T2D development. Our results revealed that AIP1 was downregulated in omental adipose tissue (OAT) of obese patients with T2D compared with that in obese patients. In addition, Pearson's correlation test showed that AIP1 was negatively correlated with the homeostatic model assessment for insulin resistance (HOMA-IR, r = -0.4829) and waist-to-hip ratio (r = -0.2614), which are major clinical indexes of T2D. As revealed by the proteomic analysis, immunohistochemistry, and ELISA, the OAT and the serum of obese patients with T2D presented high inflammatory status. And the increased inflammatory factors TNF-α and C-reactive protein C (CRP) in the serum of obese patients with T2D showed a positive correlation with HOMA-IR (TNF-α, r = 0.4728; CRP, r = 0.5522). Interestingly, AIP1 deficiency in adipocytes facilitated TNF-α secretion and retarded glucose uptake. Mechanistically, AIP1 deletion in human adipocytes activated JNK, p38 MAPK, and ERK1/2 signaling. Furthermore, inhibition of these signaling pathways using specific inhibitors could suppress these signal activation and insulin resistance caused by AIP1 deficiency. In addition, AIP1 and TNF-α expression in the OAT of patients with T2D recovered to normal levels after laparoscopic Roux-en-Y gastric bypass (RYGB) surgery. These findings indicate that AIP1 is negatively correlated with the clinical indexes of T2D. It modulates TNF-α expression in OAT via JNK, p38 MAPK, and ERK1/2 signaling.
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Affiliation(s)
- Zhigao Song
- Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Cardiovascular Surgery, Zhujiang Hospital of Southern Medical University, Guangzhou, China
| | - Cong Chen
- Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jipei He
- Department of Metabolic Surgery, Your Doctor Medical Group, Guangzhou, China
| | - Bixia Liu
- Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Weidong Ji
- Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- *Correspondence: Li He, ; Liangping Wu, ; Weidong Ji,
| | - Liangping Wu
- Department of Metabolic Surgery, Your Doctor Medical Group, Guangzhou, China
- Department of Metabolic Surgery, Jinshazhou Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, China
- *Correspondence: Li He, ; Liangping Wu, ; Weidong Ji,
| | - Li He
- Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- *Correspondence: Li He, ; Liangping Wu, ; Weidong Ji,
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Bellazzo A, Collavin L. Cutting the Brakes on Ras-Cytoplasmic GAPs as Targets of Inactivation in Cancer. Cancers (Basel) 2020; 12:cancers12103066. [PMID: 33096593 PMCID: PMC7588890 DOI: 10.3390/cancers12103066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/11/2020] [Accepted: 10/15/2020] [Indexed: 12/16/2022] Open
Abstract
Simple Summary GTPase-Activating Proteins (RasGAPs) are a group of structurally related proteins with a fundamental role in controlling the activity of Ras in normal and cancer cells. In particular, loss of function of RasGAPs may contribute to aberrant Ras activation in cancer. Here we review the multiple molecular mechanisms and factors that are involved in downregulating RasGAPs expression and functions in cancer. Additionally, we discuss how extracellular stimuli from the tumor microenvironment can control RasGAPs expression and activity in cancer cells and stromal cells, indirectly affecting Ras activation, with implications for cancer development and progression. Abstract The Ras pathway is frequently deregulated in cancer, actively contributing to tumor development and progression. Oncogenic activation of the Ras pathway is commonly due to point mutation of one of the three Ras genes, which occurs in almost one third of human cancers. In the absence of Ras mutation, the pathway is frequently activated by alternative means, including the loss of function of Ras inhibitors. Among Ras inhibitors, the GTPase-Activating Proteins (RasGAPs) are major players, given their ability to modulate multiple cancer-related pathways. In fact, most RasGAPs also have a multi-domain structure that allows them to act as scaffold or adaptor proteins, affecting additional oncogenic cascades. In cancer cells, various mechanisms can cause the loss of function of Ras inhibitors; here, we review the available evidence of RasGAP inactivation in cancer, with a specific focus on the mechanisms. We also consider extracellular inputs that can affect RasGAP levels and functions, implicating that specific conditions in the tumor microenvironment can foster or counteract Ras signaling through negative or positive modulation of RasGAPs. A better understanding of these conditions might have relevant clinical repercussions, since treatments to restore or enhance the function of RasGAPs in cancer would help circumvent the intrinsic difficulty of directly targeting the Ras protein.
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Yu Z, Zhang W, Zhang X, Xu D, Wang N. Transcription box‑3 protects human umbilical vein endothelial cells in a high‑glucose environment through sirtuin 1/AKT signaling. Mol Med Rep 2020; 22:1145-1154. [PMID: 32627000 PMCID: PMC7339771 DOI: 10.3892/mmr.2020.11237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 03/30/2020] [Indexed: 11/18/2022] Open
Abstract
The increasing burden of diabetes in low and middle-income countries is attributable to both genetic and epigenetic factors. Environmental- and lifestyle-associated changes are also considered to be important contributors to this disease. The resultant co-morbidities arising from micro-and macrovascular changes in diabetes are difficult to manage and are an economic burden. However, very little is known about the molecular mechanisms that drive this phenotype. The present study aimed to investigate the role of sirtuin 1 (SIRT1)- and transcription box-3 (TBX-3)-mediated regulation of endothelial dysfunction, given the significance of SIRT1 in glucose metabolism and the role of TBX-3 in the maintenance of cellular proliferation, senescence and apoptosis. Following the recruitment of adult patients with and without diabetes, both SIRT1 and TBX-3 expression was confirmed to be present in the sera of the patients with diabetes and the patients without diabetes; however, both SIRT1 and TBX-3 expression levels were higher in the sera of the patients with diabetes. Human umbilical vein endothelial cells (HUVECs) were further used for in vitro studies. Using TBX-3 and SIRT1 knockdown models, the cellular responses to proliferation, migration, invasion and tube formation were investigated using an MTS, cell cycle analysis, wound healing, Transwell and tube formation assay, respectively. Western blotting was also used to determine the downstream signaling pathways involved. The genetic knockdown of TBX-3 in hyperglycemic conditions significantly decreased the cellular proliferation, migration, invasion and angiogenesis of HUVECs. It was subsequently identified that TBX-3 mediated its effects through the activation of AKT and vascular endothelial growth factor (VEGF) signaling. However, the genetic knockdown of SIRT1 in the presence of TBX-3 overexpression and glucose failed to activate the AKT and VEGF signaling pathways. In conclusion, the results of the present study suggested that SIRT1 may positively regulate TBX-3 in endothelial cells, therefore, SIRT1 and/or TBX-3 may serve as potential novel biomarkers for disease progression.
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Affiliation(s)
- Zhanjiang Yu
- Department of General Surgery, The Third Affiliated Hospital of Qiqihar Medical University, Qiqihar, Heilongjiang 161000, P.R. China
| | - Wei Zhang
- Department of Endocrinology, The Third Affiliated Hospital of Qiqihar Medical University, Qiqihar, Heilongjiang 161000, P.R. China
| | - Xiankun Zhang
- Department of Laboratory, The Third Affiliated Hospital of Qiqihar Medical University, Qiqihar, Heilongjiang 161000, P.R. China
| | - Donghui Xu
- Department of General Surgery, The Third Affiliated Hospital of Qiqihar Medical University, Qiqihar, Heilongjiang 161000, P.R. China
| | - Na Wang
- Department of Psychology, Qiqihar Medical University, Qiqihar, Heilongjiang 161000, P.R. China
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Kong Y, Cheng L, Ma L, Li H, Cheng B, Zhao Y. Norepinephrine protects against apoptosis of mesenchymal stem cells induced by high glucose. J Cell Physiol 2019; 234:20801-20815. [PMID: 31032949 DOI: 10.1002/jcp.28686] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 03/19/2019] [Accepted: 03/25/2019] [Indexed: 02/06/2023]
Abstract
In diabetes, the number of bone mesenchymal stem cells (MSCs) decreases and their differentiation is impaired. However, the exact mechanism is unclear. Patients with diabetes often experience sympathetic nerve injury. Norepinephrine (NE), a major mediator of the sympathetic nervous system, influences rat MSC migration in culture and in vivo. The present study aimed to investigate the effect of NE on MSCs under high glucose conditions; therefore MSCs were treated with high glucose and NE. High glucose-induced MSCs apoptosis, which was reversed by NE. To verify the effect of NE, mice underwent sympathectomy and were used to establish a diabetic model. Diabetic mice with sympathectomy had a higher apoptosis rate and higher levels of reactive oxygen species in their bone marrow-derived cells than diabetic mice without sympathectomy. High glucose inhibited p-AKT production and B-Cell CLL/Lymphoma 2 expression, and promoted BAX and caspase-3 expression. NE reversed these effects of high glucose. An AKT inhibitor enhanced the effects of high glucose. Thus, NE had a protective effect on MSC apoptosis induced by high glucose, possibly via the AKT/BCL-2 pathway.
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Affiliation(s)
- Yanan Kong
- Department of Plastic Surgery, The First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Liuhanghang Cheng
- Department of Plastic Surgery and Burn Center, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Li Ma
- Department of Plastic Surgery, The First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Haihong Li
- Department of Plastic Surgery and Burn Center, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Biao Cheng
- Guangzhou School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
- Department of Plastic Surgery, General Hospital of Southern Theater Command, PLA, Guangzhou, Guangdong, People's Republic of China
- The Key Laboratory of Trauma Treatment & Tissue Repair of Tropical Area, PLA, Guangzhou, Guangdong, People's Republic of China
| | - Yu Zhao
- Department of Plastic Surgery, The First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, People's Republic of China
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Fadini GP, Albiero M, Bonora BM, Avogaro A. Angiogenic Abnormalities in Diabetes Mellitus: Mechanistic and Clinical Aspects. J Clin Endocrinol Metab 2019; 104:5431-5444. [PMID: 31211371 DOI: 10.1210/jc.2019-00980] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/12/2019] [Indexed: 12/25/2022]
Abstract
CONTEXT Diabetes causes severe pathological changes to the microvasculature in many organs and tissues and is at the same time associated with an increased risk of coronary and peripheral macrovascular events. We herein review alterations in angiogenesis observed in human and experimental diabetes and how they contribute to diabetes onset and development of vascular complications. EVIDENCE ACQUISITION The English language medical literature was searched for articles reporting on angiogenesis/vasculogenesis abnormalities in diabetes and their clinical manifestations, mechanistic aspects, and possible therapeutic implications. EVIDENCE SYNTHESIS Angiogenesis is a complex process, driven by a multiplicity of molecular mechanisms and involved in several physiological and pathological conditions. Incompetent angiogenesis is pervasive in diabetic vascular complications, with both excessive and defective angiogenesis observed in various tissues. A striking different angiogenic response typically occurs in the retina vs the myocardium and peripheral circulation, but some commonalities in abnormal angiogenesis can explain the well-known association between microangiopathy and macroangiopathy. Impaired angiogenesis can also affect endocrine islet and adipose tissue function, providing a link to diabetes onset. Exposure to high glucose itself directly affects angiogenic/vasculogenic processes, and the mechanisms include defective responses to hypoxia and proangiogenic factors, impaired nitric oxide bioavailability, shortage of proangiogenic cells, and loss of pericytes. CONCLUSIONS Dissecting the molecular drivers of tissue-specific alterations of angiogenesis/vasculogenesis is an important challenge to devise new therapeutic approaches. Angiogenesis-modulating therapies should be carefully evaluated in view of their potential off-target effects. At present, glycemic control remains the most reasonable therapeutic strategy to normalize angiogenesis in diabetes.
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Affiliation(s)
- Gian Paolo Fadini
- Department of Medicine, University of Padova, Padova, Italy
- Venetian Institute of Molecular Medicine, Padova, Italy
| | - Mattia Albiero
- Department of Medicine, University of Padova, Padova, Italy
- Venetian Institute of Molecular Medicine, Padova, Italy
| | - Benedetta Maria Bonora
- Department of Medicine, University of Padova, Padova, Italy
- Venetian Institute of Molecular Medicine, Padova, Italy
| | - Angelo Avogaro
- Department of Medicine, University of Padova, Padova, Italy
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Block one, unleash a hundred. Mechanisms of DAB2IP inactivation in cancer. Cell Death Differ 2016; 24:15-25. [PMID: 27858941 DOI: 10.1038/cdd.2016.134] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/26/2016] [Accepted: 10/12/2016] [Indexed: 02/07/2023] Open
Abstract
One of the most defining features of cancer is aberrant cell communication; therefore, a molecular understanding of the intricate network established among tumor cells and their microenvironment could significantly improve comprehension and clinical management of cancer. The tumor suppressor DAB2IP (Disabled homolog 2 interacting protein), also known as AIP1 (ASK1 interacting protein), has an important role in this context, as it modulates signal transduction by multiple inflammatory cytokines and growth factors. DAB2IP is a Ras-GAP, and negatively controls Ras-dependent mitogenic signals. In addition, acting as a signaling adaptor, DAB2IP modulates other key oncogenic pathways, including TNFα/NF-κB, WNT/β-catenin, PI3K/AKT, and androgen receptors. Therefore, DAB2IP inactivation can provide a selective advantage to tumors initiated by a variety of driver mutations. In line with this role, DAB2IP expression is frequently impaired by methylation in cancer. Interestingly, recent studies reveal that tumor cells can employ other sophisticated mechanisms to disable DAB2IP at the post-transcriptional level. We review the mechanisms and consequences of DAB2IP inactivation in cancer, with the purpose to support and improve research aimed to counteract such mechanisms. We suggest that DAB2IP reactivation in cancer cells could be a strategy to coordinately dampen multiple oncogenic pathways, potentially limiting progression of a wide spectrum of tumors.
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Hu JL, Liu LP, Yang SL, Fang X, Wen L, Ren QG, Yu C. Hepatitis B virus induces hypoxia-inducible factor-2α expression through hepatitis B virus X protein. Oncol Rep 2016; 35:1443-8. [PMID: 26647960 DOI: 10.3892/or.2015.4480] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 11/01/2015] [Indexed: 01/15/2023] Open
Abstract
A growing number of studies suggest that the hepatitis B virus X protein (HBx) enhances the protein stability of the hypoxia-inducible factor-1α (HIF-1α). However, the relationship between hepatitis B virus (HBV), HBx and hypoxia-inducible factor-2α (HIF-2α) has not yet been fully elucidated. Immunohistochemical analysis was employed to detect the expression of HIF-2α in normal liver, HBV-related chronic hepatitis, and HBV-related and non-HBV-related hepatocellular carcinoma (HCC) tissues. Quantitative real‑time PCR (qPCR) and western blotting were used to investigate the impact of HBV and HBx on the expression of HIF‑2α. Immunoprecipitation and immunofluorescence were applied to explore the underlying mechanisms. The HIF‑2α expression was found to be higher in HBV‑related chronic hepatitis tissues than in normal liver tissues. Furthermore, it was higher in HBV‑related HCC tissues and HBV‑integrated HepG2 cells than in the corresponding non‑HBV‑related HCC tissues and HepG2 cells. Both HBV and HBx enhanced the protein stability of HIF‑2α. HBx‑mediated upregulation of HIF‑2α resulted mainly from an inhibition of the degradation of HIF‑2α due to the binding of HBx to the von Hippel‑Lindau protein (pVHL). In addition, HBx upregulated the expression of HIF‑2α by activating the NF‑κB signaling pathway. Thus, the present study identified that HBV induces the HIF‑2α expression through its encoded protein HBx. This upregulates the HIF-2α expression by binding to the pVHL activating the NF-κB signaling pathway.
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Affiliation(s)
- Jian-Li Hu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Li-Ping Liu
- Department of Hepatobiliary and Pancreas Surgery, The Second Clinical Medical College of Jinan University (Shenzhen People's Hospital), Shenzhen, Guangdong 518020, P.R. China
| | - Sheng-Li Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Xiefan Fang
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Lu Wen
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Quan-Guang Ren
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Chao Yu
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guiyang Medical College, Guiyang, Guizhou 550001, P.R. China
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