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Alhusaini AM, Fadda LM, Alanazi AM, Sarawi WS, Alomar HA, Ali HM, Hasan IH, Ali RA. Nano-Resveratrol: A Promising Candidate for the Treatment of Renal Toxicity Induced by Doxorubicin in Rats Through Modulation of Beclin-1 and mTOR. Front Pharmacol 2022; 13:826908. [PMID: 35281939 PMCID: PMC8913579 DOI: 10.3389/fphar.2022.826908] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/17/2022] [Indexed: 12/30/2022] Open
Abstract
Background: Although doxorubicin (DXR) is one of the most used anticancer drugs, it can cause life-threatening renal damage. There has been no effective treatment for DXR-induced renal damage until now. Aim: This work aims at examining the potential impact of nano-resveratrol (N-Resv), native resveratrol (Resv), and their combination with carvedilol (Card) against DXR-induced renal toxicity in rats and to investigate the mechanisms through which these antioxidants act to ameliorate DXR nephrotoxicity. Method: DXR was administered to rats (2 mg/kg, i.p.) twice weekly over 5 weeks. The antioxidants in question were taken 1 week before the DXR dose for 6 weeks. Results: DXR exhibited an elevation in serum urea, creatinine, renal lipid peroxide levels, endoglin expression, kidney injury molecule-1 (KIM-1), and beclin-1. On the other hand, renal podocin and mTOR expression and GSH levels were declined. In addition, DNA fragmentation was markedly increased in the DXR-administered group. Treatment with either Resv or N-Resv alone or in combination with Card ameliorated the previously measured parameters. Conclusion: N-Resv showed superior effectiveness relative to Resv in most of the measured parameters. Histopathological examination revealed amelioration of renal structural and cellular changes after DXR by Card and N-Resv, thus validating the previous biochemical and molecular results.
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Affiliation(s)
- Ahlam M. Alhusaini
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
- *Correspondence: Ahlam M. Alhusaini,
| | - Laila M. Fadda
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Abeer M. Alanazi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Wedad S. Sarawi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Hatun A. Alomar
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Hanaa M. Ali
- Genetics and Cytology Department, National Research Centre, Cairo, Egypt
| | - Iman H. Hasan
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Rehab Ahmed Ali
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
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2
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Overexpression of Programmed Cell Death 1 Prevents Doxorubicin-Induced Apoptosis Through Autophagy Induction in H9c2 Cardiomyocytes. Cardiovasc Toxicol 2022; 22:462-476. [PMID: 35190965 PMCID: PMC8993749 DOI: 10.1007/s12012-022-09726-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/02/2022] [Indexed: 12/11/2022]
Abstract
Doxorubicin (DOX) is a potent chemotherapeutic agent; however, it causes severe heart injury via apoptosis induction in many patients. DOX-induced cardiotoxicity is attenuated by activated autophagy in the heart. We previously found that programmed cell death 1 (Pdcd1), an immune checkpoint receptor, inhibits DOX-induced cardiomyocyte apoptosis. In this study, we investigated whether autophagy contributes to the protective role of Pdcd1 against DOX-induced cardiomyocyte apoptosis. We also examined the role of Pdcd1 in DOX-induced apoptosis in cancer cells. Rat cardiomyocyte cell line H9c2 and human cancer cell lines K562 and MCF-7 were transfected with Pdcd1-encoding plasmid DNA to establish Pdcd1-overexpressing cells. Apoptosis and autophagy were determined using a luciferase assay. In H9c2 cells, DOX-induced apoptosis and viability reduction occurred through caspase activation. In particular, Pdcd1 overexpression activated the autophagy pathway through the inhibition of the mammalian target of rapamycin, a major negative regulator of autophagy. Moreover, it prevented DOX-induced cardiomyocyte apoptosis; a similar cardioprotection was observed when normal H9c2 cells (without Pdcd1 overexpression) were treated with rapamycin, an autophagy inducer, before the DOX treatment. Conversely, in cancer cells, Pdcd1 overexpression increased both basal and DOX-induced apoptosis. The role of Pdcd1 in DOX-induced apoptosis in cardiomyocytes and cancer cells was opposing. Pdcd1 signaling prevented DOX-induced apoptosis in cardiomyocytes, through autophagy induction; it enhanced DOX-induced apoptosis in cancer cells. Therefore, Pdcd1 could be a critical molecule for more effective and safer DOX chemotherapy.
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3
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Vu M, Kassouf N, Ofili R, Lund T, Bell C, Appiah S. Doxorubicin selectively induces apoptosis through the inhibition of a novel isoform of Bcl‑2 in acute myeloid leukaemia MOLM‑13 cells with reduced Beclin 1 expression. Int J Oncol 2020; 57:113-121. [PMID: 32377726 PMCID: PMC7252449 DOI: 10.3892/ijo.2020.5052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 04/06/2020] [Indexed: 02/06/2023] Open
Abstract
The overexpression of anti-apoptotic Bcl-2 in acute myeloid leukaemia (AML) may contribute to difficulties in eradicating these cells during chemotherapy. In the present study, doxorubicin (Dox) was evaluated for its potential to induce selective apoptotic cell death in AML MOLM-13 cells and to modulate autophagy through Bcl-2 and Beclin 1 protein expression. Annexin V/propidium iodide and 5(6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) flow cytometric analyses were conducted to determine the effects of Dox on cell death and cell proliferation, respectively, following 48 h of co-incubation with AML MOLM-13 or U-937 monocytic cells. The protein expression levels of Bcl-2 and Beclin 1 in untreated and treated cells were quantified by western blot analysis. Dox reduced the viability of MOLM-13 cells partly by inhibiting cell division and inducing cell apoptosis. Dox demonstrated a level of selectivity in its cytotoxicity against MOLM-13 compared to U-937 cells (P<0.05). Dox induced a significant decrease in Beclin 1 protein levels in MOLM-13 cells without significantly affecting the protein levels in U-937 monocytes. A novel Bcl-2 15-20 kDa (p15-20-Bcl-2) isoform was found to be selectively expressed in AML MOLM-13 cells (but absent in the leukaemic cell lines tested, OCI-AML2, CML K562 and U-937). Dox induced a highly significant inhibition of p15-20-Bcl-2 at concentrations of 0.5, 0.75 and 1 µM (P<0.01). However, the usual 26 kDa Bcl-2 (p26-Bcl-2-α) isoform protein expression was not affected by the drug in either the MOLM-13 or U-937 cells. It was thus postulated that Dox exhibited some selectivity by targeting the p15-20-Bcl-2 isoform in MOLM-13 cells and activating Beclin 1 to induce cell death.
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Affiliation(s)
- Milan Vu
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London NW4 4BT, UK
| | - Nick Kassouf
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London NW4 4BT, UK
| | - Rosemary Ofili
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London NW4 4BT, UK
| | - Torben Lund
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London NW4 4BT, UK
| | - Celia Bell
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London NW4 4BT, UK
| | - Sandra Appiah
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London NW4 4BT, UK
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4
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Courreges AP, Najenson AC, Vatta MS, Bianciotti LG. Atrial natriuretic peptide attenuates endoplasmic reticulum stress in experimental acute pancreatitis. Biochim Biophys Acta Mol Basis Dis 2018; 1865:485-493. [PMID: 30529145 DOI: 10.1016/j.bbadis.2018.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 11/19/2018] [Accepted: 12/05/2018] [Indexed: 12/30/2022]
Abstract
Increasing evidence shows that the endoplasmic reticulum (ER) stress is an early event that injures pancreatic acinar cells and contributes to the pathogenesis of acute pancreatitis. In the present work we sought to establish whether atrial natriuretic peptide (ANP) alleviated ER stress in rats with cerulein-induced pancreatitis. The major components of the unfolded protein response (UPR) and their downstream effectors were assessed by immunoblotting or fluorimetry and the ultrastructure of ER evaluated by electron transmission microscopy. Cross-talk with autophagy was evaluated by beclin-1 expression. ANP reduced binding immunoglobulin protein (Bip) expression (UPR major controller) which under non-stress conditions keeps inactive the stress sensor proteins: protein kinase-like ER kinase (PERK), inositol-requiring enzyme-1 (IRE1) and activating transcription factor 6 (ATF6). Although ANP did not change PERK expression it decreased p-eIF2α and enhanced downstream effector CHOP, suggesting that ANP stimulates ER-dependent apoptosis. In accordance, ANP also decreased Bcl2 expression and enhanced proapoptotic proteins Bax and Bak. The atrial peptide enhanced ATF6 expression and although it did not affect IRE1/sXBP1 signaling, it increased caspase-2 activity, also involved in ER-dependent apoptosis. Furthermore, ANP decreased beclin-1 expression. The ultrastructure of the RE revealed decreased swelling and conserved ribosomes in the presence of ANP. Present findings support that ANP alleviates ER stress in acute pancreatitis by modulating the three branches of the UPR and stimulates ER-dependent apoptosis. Gaining insights into the modulation of ER stress may help to develop specific therapeutic strategies for acute pancreatitis and/or medical interventions at risk of its developing like endoscopic retrograde cholangiopancreatography.
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Affiliation(s)
- Ana Paula Courreges
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Ana Clara Najenson
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Marcelo S Vatta
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiología, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA), Buenos Aires, Argentina
| | - Liliana G Bianciotti
- CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiopatología, Buenos Aires, Argentina.
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5
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Liu GS, Zhu H, Cai WF, Wang X, Jiang M, Essandoh K, Vafiadaki E, Haghighi K, Lam CK, Gardner G, Adly G, Nicolaou P, Sanoudou D, Liang Q, Rubinstein J, Fan GC, Kranias EG. Regulation of BECN1-mediated autophagy by HSPB6: Insights from a human HSPB6 S10F mutant. Autophagy 2018; 14:80-97. [PMID: 29157081 DOI: 10.1080/15548627.2017.1392420] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
HSPB6/Hsp20 (heat shock protein family B [small] member 6) has emerged as a novel cardioprotector against stress-induced injury. We identified a human mutant of HSPB6 (HSPB6S10F) exclusively present in dilated cardiomyopathy (DCM) patients. Cardiac expression of this mutant in mouse hearts resulted in remodeling and dysfunction, which progressed to heart failure and early death. These detrimental effects were associated with reduced interaction of mutant HSPB6S10F with BECN1/Beclin 1, leading to BECN1 ubiquitination and its proteosomal degradation. As a result, autophagy flux was substantially inhibited and apoptosis was increased in HSPB6S10F-mutant hearts. In contrast, overexpression of wild-type HSPB6 (HSPB6 WT) not only increased BECN1 levels, but also competitively suppressed binding of BECN1 to BCL2, resulting in stimulated autophagy. Indeed, preinhibition of autophagy attenuated the cardioprotective effects of HSPB6 WT. Taken together, these findings reveal a new regulatory mechanism of HSPB6 in cell survival through its interaction with BECN1. Furthermore, Ser10 appears to be crucial for the protective effects of HSPB6 and transversion of this amino acid to Phe contributes to cardiomyopathy.
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Affiliation(s)
- Guan-Sheng Liu
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Hongyan Zhu
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Wen-Feng Cai
- b Department of Pathology & Lab Medicine , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Xiaohong Wang
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Min Jiang
- c Department of Internal Medicine , University of Cincinnati College of Medicine. Cincinnati , OH , USA
| | - Kobina Essandoh
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Elizabeth Vafiadaki
- d Molecular Biology Division, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens , Athens , Greece
| | - Kobra Haghighi
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Chi Keung Lam
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - George Gardner
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - George Adly
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Persoulla Nicolaou
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Despina Sanoudou
- d Molecular Biology Division, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens , Athens , Greece
| | - Qiangrong Liang
- e Department of Biomedical Sciences , New York Institute of Technology College of Osteopathic Medicine , Old Westbury , NY , USA
| | - Jack Rubinstein
- c Department of Internal Medicine , University of Cincinnati College of Medicine. Cincinnati , OH , USA
| | - Guo-Chang Fan
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA
| | - Evangelia G Kranias
- a Department of Pharmacology & System Physiology , University of Cincinnati College of Medicine, Cincinnati , OH , USA.,d Molecular Biology Division, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens , Athens , Greece
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6
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Chen L, Qian M, Zhang L, Xia J, Bao Y, Wang J, Guo L, Li Y. Co-delivery of doxorubicin and shRNA of Beclin1 by folate receptor targeted pullulan-based multifunctional nanomicelles for combinational cancer therapy. RSC Adv 2018; 8:17710-17722. [PMID: 35542072 PMCID: PMC9080481 DOI: 10.1039/c8ra01679h] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/01/2018] [Indexed: 12/22/2022] Open
Abstract
Doxorubicin (DOX) is a widely-used effective antitumor agent. However, its clinical application is limited due to its side effects including anti-apoptotic defense of cancer cells caused by DOX-induced autophagy and deleterious effects in normal tissues. Therefore, in this study, a new folate (FA)-decorated amphiphilic bifunctional pullulan-based copolymer (named as FPDP) was developed as an efficient nano-carrier for the co-delivery of DOX and short hairpin RNA of Beclin1, a pivotal autophage-related gene, to enhance the anticancer effect of DOX by the blockade of the Beclin1 protein mediated autophagy process. In FPDP molecules, pullulan was modified with lipophilic desoxycholic acid for the formation of micelles, the introduced low molecular weight (1 kDa) branched polyethylenimine (PEI) was for shBeclin1 delivery, and folate (FA) was employed as the tumor-targeting group. FPDP micelles demonstrated an average diameter of 161.9 nm, good biocompatibility, applicable storage stability, excellent loading capacities for both DOX and shBeclin1 and a sustained drug release profile. In vitro cell culture experiments demonstrated that the uptake amount of FPDP/DOX micelles in folate receptor positive (FR+) HeLa cells was more than that in folate receptor negative (FR−) HepG2 cells, leading to significantly higher cytotoxicity against FR+ HeLa cells. The simultaneous co-delivery of shBeclin1 and DOX to HeLa cells with FPDP micelles led to efficient reduction in the expression level of Beclin1 as well as synergistic cell apoptotic induction. Furthermore, in vivo studies revealed superior antitumor efficacy of tumor-targeted FPDP/DOX/shBeclin1 in comparison with non-FR-targeted PDP micelles and free DOX. These results highlighted that co-delivery of DOX and shRNA of Beclin1 with FPDP micelles has the potential to overcome the limitations of DOX in clinical cancer therapy. New folate receptor targeted nano-micelles enhanced the anticancer effect of doxorubicin by shBeclin1 with the blockade of the autophagy process.![]()
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Affiliation(s)
- Lili Chen
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian
- P. R. China
- School of Life Science and Biotechnology
| | - Ming Qian
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Liuwei Zhang
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Jing Xia
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Yongming Bao
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Jingyun Wang
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian
- P. R. China
- School of Life Science and Biotechnology
| | - Lianying Guo
- Department of Environmental Health and Toxicology
- School of Public Health
- Dalian Medical University
- Dalian
- P. R. China
| | - Yachen Li
- Department of Environmental Health and Toxicology
- School of Public Health
- Dalian Medical University
- Dalian
- P. R. China
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7
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Zhen Z, Yang K, Ye L, You Z, Chen R, Liu Y, He Y. Suberoylanilide hydroxamic acid sensitizes neuroblastoma to paclitaxel by inhibiting thioredoxin-related protein 14-mediated autophagy. Cancer Sci 2017; 108:1485-1492. [PMID: 28498513 PMCID: PMC5497723 DOI: 10.1111/cas.13279] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/01/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022] Open
Abstract
Paclitaxel is not as effective for neuroblastoma as most of the front‐line chemotherapeutics due to drug resistance. This study explored the regulatory mechanism of paclitaxel‐associated autophagy and potential solutions to paclitaxel resistance in neuroblastoma. The formation of autophagic vesicles was detected by scanning transmission electron microscopy and flow cytometry. The autophagy‐associated proteins were assessed by western blot. Autophagy was induced and the autophagy‐associated proteins LC3‐I, LC3‐II, Beclin 1, and thioredoxin‐related protein 14 (TRP14), were found to be upregulated in neuroblastoma cells that were exposed to paclitaxel. The inhibition of Beclin 1 or TRP14 by siRNA increased the sensitivity of the tumor cells to paclitaxel. In addition, Beclin 1‐mediated autophagy was regulated by TRP14. Furthermore, the TRP14 inhibitor suberoylanilide hydroxamic acid (SAHA) downregulated paclitaxel‐induced autophagy and enhanced the anticancer effects of paclitaxel in normal control cancer cells but not in cells with upregulated Beclin 1 and TRP14 expression. Our findings showed that paclitaxel‐induced autophagy in neuroblastoma cells was regulated by TRP14 and that SAHA could sensitize neuroblastoma cells to paclitaxel by specifically inhibiting TRP14.
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Affiliation(s)
- Zijun Zhen
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Department of Pediatric Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,Collaborative Innovation Center of Cancer Medicine, Guangzhou, China
| | - Kaibin Yang
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Sun Yat-sen University Zhongshan School of Medicine, Guangzhou, China
| | - Litong Ye
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Sun Yat-sen University Zhongshan School of Medicine, Guangzhou, China
| | - Zhiyao You
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Sun Yat-sen University Zhongshan School of Medicine, Guangzhou, China
| | - Rirong Chen
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Sun Yat-sen University Zhongshan School of Medicine, Guangzhou, China
| | - Ying Liu
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Sun Yat-sen University Zhongshan School of Medicine, Guangzhou, China
| | - Youjian He
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.,Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China
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8
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Xu X, Fu Y, Tong J, Fan S, Xu K, Sun H, Liang Y, Yan C, Yuan Z, Ge Y. MicroRNA-216b/Beclin 1 axis regulates autophagy and apoptosis in human Tenon's capsule fibroblasts upon hydroxycamptothecin exposure. Exp Eye Res 2014; 123:43-55. [DOI: 10.1016/j.exer.2014.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/17/2014] [Accepted: 03/20/2014] [Indexed: 10/25/2022]
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9
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Giuliani CM, Dass CR. Metabolic stress and cancer: is autophagy the common denominator and a feasible target? ACTA ACUST UNITED AC 2013; 66:597-614. [PMID: 24341996 DOI: 10.1111/jphp.12191] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 10/23/2013] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Autophagy facilitates the degradation of proteins or organelles into recyclable molecules, which are released into the cell to foster cell survival under energetic stress. Furthermore, autophagy has been associated with cancer cell survival and chemoresistance, and as such, it is an area of increasing interest. As autophagic activity and its regulation are related to metabolism and energy stress, it is critical to elucidate the exact molecular mechanisms that drive it. KEY FINDINGS Cancer is recognised to have specific metabolic changes, which include the switch from oxidative phosphorylation to glycolysis. Although the exact rationale is yet to be determined, it is proposed to limit hypoxic stress and generate substrates for biosynthesis. The various forms of energetic stress including hypoxia, glucose and amino acid deprivation have been reviewed in relation to their effect on autophagy and certain key molecules identified to date. These key molecules, which include AMP-activated protein kinase, mammalian target of rapamycin complex 1, adenosine triphosphate and reactive oxygen species, are all implicated as key stimuli of autophagic activity, as will be discussed in this review. SUMMARY These findings indicate that autophagic regulation could be a means to better cancer treatment.
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Affiliation(s)
- Charlett M Giuliani
- School of Biomedical and Health Sciences, Victoria University, St Albans, Victoria, Australia
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10
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Tacar O, Dass CR. Doxorubicin-induced death in tumour cells and cardiomyocytes: is autophagy the key to improving future clinical outcomes? J Pharm Pharmacol 2013; 65:1577-89. [DOI: 10.1111/jphp.12144] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 08/20/2013] [Indexed: 12/16/2022]
Abstract
Abstract
Objectives
Doxorubicin, a commonly used frontline chemotherapeutic agent for cancer, is not without side-effects. The original thinking that the drug causes necrosis in tumours has largely given way to its link with apoptosis over the past two decades.
Key findings
More recently, major biomarkers such as AMPK, p53 and Bcl-2 have been identified as important to apoptosis induction by doxorubicin. It is Bcl-2 and its interaction with Beclin-1 that has refocussed research attention on doxorubicin, albeit this time for its ability to induce autophagy. Autophagy can be either anticancerous or procancerous however, so it is critical that the reasons for which cancer cells undergo this type of cell biological event be clearly identified for future exploitation.
Summary
Taking a step back from treating patients with large doses of doxorubicin, which causes toxicity to the heart amongst other organs, and further research with this drug's molecular signalling in not only neoplastic but normal cells, may indeed redefine the way doxorubicin is used clinically and potentially lead to better neoplastic disease management.
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Affiliation(s)
- Oktay Tacar
- College of Biomedicine and Health, Victoria University, St. Albans, Vic., Australia
| | - Crispin R Dass
- Biosciences Research Precinct, Curtin University, Bentley, WA, Australia
- School of Pharmacy, Curtin University, Bentley, WA, Australia
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11
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Lee YJ, Song HO, Lee YH, Ryu JS, Ahn MH. Proliferation of Toxoplasma gondii suppresses host cell autophagy. THE KOREAN JOURNAL OF PARASITOLOGY 2013; 51:279-87. [PMID: 23864738 PMCID: PMC3712101 DOI: 10.3347/kjp.2013.51.3.279] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/10/2013] [Accepted: 05/10/2013] [Indexed: 12/04/2022]
Abstract
Autophagy is a process of cytoplasmic degradation of endogenous proteins and organelles. Although its primary role is protective, it can also contribute to cell death. Recently, autophagy was found to play a role in the activation of host defense against intracellular pathogens. The aims of our study was to investigate whether host cell autophagy influences Toxoplasma gondii proliferation and whether autophagy inhibitors modulate cell survival. HeLa cells were infected with T. gondii with and without rapamycin treatment to induce autophagy. Lactate dehydrogenase assays showed that cell death was extensive at 36-48 hr after infection in cells treated with T. gondii with or without rapamycin. The autophagic markers, LC3 II and Beclin 1, were strongly expressed at 18-24 hr after exposure as shown by Western blotting and RT-PCR. However, the subsequent T. gondii proliferation suppressed autophagy at 36 hr post-infection. Pre-treatment with the autophagy inhibitor, 3-methyladenine (3-MA), down-regulated LC3 II and Beclin 1. The latter was also down-regulated by calpeptin, a calpain inhibitor. Monodansyl cadaverine (MDC) staining detected numerous autophagic vacuoles (AVs) at 18 hr post-infection. Ultrastructural observations showed T. gondii proliferation in parasitophorous vacuoles (PVs) coinciding with a decline in the numbers of AVs by 18 hr. FACS analysis failed to confirm the presence of cell apoptosis after exposure to T. gondii and rapamycin. We concluded that T. gondii proliferation may inhibit host cell autophagy and has an impact on cell survival.
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Affiliation(s)
- Youn-Jin Lee
- Department of Environmental Biology and Medical Parasitology, Hanyang University College of Medicine, Seoul 133-791, Korea
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12
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MA TAI, LI YUANYUAN, ZHU JIE, FAN LULU, DU WEIDONG, WU CHANGHAO, SUN GUOPING, LI JIABIN. Enhanced autophagic flux by endoplasmic reticulum stress in human hepatocellular carcinoma cells contributes to the maintenance of cell viability. Oncol Rep 2013; 30:433-40. [DOI: 10.3892/or.2013.2474] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 04/26/2013] [Indexed: 11/05/2022] Open
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Liu C, Yan X, Wang HQ, Gao YY, Liu J, Hu Z, Liu D, Gao J, Lin B. Autophagy-independent enhancing effects of Beclin 1 on cytotoxicity of ovarian cancer cells mediated by proteasome inhibitors. BMC Cancer 2012; 12:622. [PMID: 23270461 PMCID: PMC3553022 DOI: 10.1186/1471-2407-12-622] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 12/17/2012] [Indexed: 01/11/2023] Open
Abstract
Background The ubiquitin-proteasome system and macroautophagy (hereafter referred to autophagy) are two complementary pathways for protein degradation. Emerging evidence suggests that proteasome inhibition might be a promising approach for tumor therapy. Accumulating data suggest that autophagy is activated as a compensatory mechanism upon proteasome activity is impaired. Method Autophagy activation was measured using acridine orange staining and LC3 transition. Cell viability and apoptosis were measured using MTT assay and flow cytometry, respectively. Beclin 1 expression vectors or shRNA against Beclin 1 (shBeclin 1) were transfected to investigate the role of Beclin 1 in autophagy activation and cytotoxicity of ovarian cancer cells induced by proteasome inhibitors. Results Proteasome inhibitors suppressed proliferation and induced autophagy in ovarian cancer cells. Neither phosphoinositide 3-kinase (PI3K) inhibitors nor shRNA against Beclin 1 could abolish the formation of acidic vacuoles and the processing of LC3 induced by proteasome inhibitors. Moreover, Beclin 1 overexpression enhanced anti-proliferative effects of proteasome inhibitors in ovarian cancer cells. Conclusions For the first time, the current study demonstrated that proteasome inhibitors induced PI3K and Beclin 1-independent autophagy in ovarian cancer cells. In addition, this study revealed autophagy-independent tumor suppressive effects of Beclin 1 in ovarian cancer cells.
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Affiliation(s)
- Chuan Liu
- Department of Obstetrics & Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang 110004, China
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Cheng Y, Sk UH, Zhang Y, Ren X, Zhang L, Huber-Keener KJ, Sun YW, Liao J, Amin S, Sharma AK, Yang JM. Rational incorporation of selenium into temozolomide elicits superior antitumor activity associated with both apoptotic and autophagic cell death. PLoS One 2012; 7:e35104. [PMID: 22496897 PMCID: PMC3320619 DOI: 10.1371/journal.pone.0035104] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 03/08/2012] [Indexed: 01/23/2023] Open
Abstract
Background The DNA alkylating agent temozolomide (TMZ) is widely used in the treatment of human malignancies such as glioma and melanoma. On the basis of previous structure-activity studies, we recently synthesized a new TMZ selenium analog by rationally introducing an N-ethylselenocyanate extension to the amide functionality in TMZ structure. Principal Findings This TMZ-Se analog showed a superior cytotoxicity to TMZ in human glioma and melanoma cells and a more potent tumor-inhibiting activity than TMZ in mouse glioma and melanoma xenograft model. TMZ-Se was also effective against a TMZ-resistant glioma cell line. To explore the mechanism underlying the superior antitumor activity of TMZ-Se, we compared the effects of TMZ and TMZ-Se on apoptosis and autophagy. Apoptosis was significantly increased in tumor cells treated with TMZ-Se in comparison to those treated with TMZ. TMZ-Se also triggered greater autophagic response, as compared with TMZ, and suppressing autophagy partly rescued cell death induced by TMZ-Se, indicating that TMZ-Se-triggered autophagy contributed to cell death. Although mRNA level of the key autophagy gene, Beclin 1, was increased, Beclin 1 protein was down-regulated in the cells treated with TMZ-Se. The decrease in Beclin 1 following TMZ-Se treatment were rescued by the calpain inhibitors and the calpain-mediated degradation of Beclin1 had no effect on autophagy but promoted apoptosis in cells treated with TMZ-Se. Conclusions Our study indicates that incorporation of Se into TMZ can render greater potency to this chemotherapeutic drug.
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Affiliation(s)
- Yan Cheng
- Department of Pharmacology and The Penn State Hershey Cancer Institute, The Pennsylvania State University College of Medicine and Milton S Hershey Medical Center, Hershey, Pennsylvania, United States of America
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15
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Nayvelt I, John S, Hsu HC, Yang P, Liu W, Das G, Hyvönen MT, Alhonen L, Keinänen TA, Shirahata A, Patel R, Thomas T, Thomas TJ. A potential estrogen mimetic effect of a bis(ethyl)polyamine analogue on estrogen receptor positive MCF-7 breast cancer cells. Amino Acids 2011; 42:899-911. [PMID: 21830120 DOI: 10.1007/s00726-011-1005-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 06/15/2011] [Indexed: 11/28/2022]
Abstract
BE-3-3-3-3 (1,15-(ethylamino)4,8,12-triazapentadecane) is a bis(ethyl)polyamine analogue under investigation as a therapeutic agent for breast cancer. Since estradiol (E(2)) is a critical regulatory molecule in the growth of breast cancer, we examined the effect of BE-3-3-3-3 on estrogen receptor α (ERα) positive MCF-7 cells in the presence and absence of E(2). In the presence of E(2), a concentration-dependent decrease in DNA synthesis was observed using [(3)H]-thymidine incorporation assay. In the absence of E(2), low concentrations (2.5-10 μM) of BE-3-3-3-3 increased [(3)H]-thymidine incorporation at 24 and 48 h. BE-3-3-3-3 induced the expression of early response genes, c-myc and c-fos, in the absence of E(2), but not in its presence, as determined by real-time quantitative polymerase chain reaction (qPCR). BE-3-3-3-3 had no significant effect on these genes in an ERα-negative cell line, MDA-MB-231. Chromatin immunoprecipitation assay demonstrated enhanced promoter occupation by either E(2) or BE-3-3-3-3 of an estrogen-responsive gene pS2/Tff1 by ERα and its co-activator, steroid receptor co-activator 3 (SRC-3). Confocal microscopy of BE-3-3-3-3-treated cells revealed membrane localization of ERα, similar to that induced by E(2). The failure of BE-3-3-3-3 to inhibit cell proliferation was associated with autophagic vacuole formation, and the induction of Beclin 1 and MAP LC3 II. These results indicate a differential effect of BE-3-3-3-3 on MCF-7 cells in the absence and presence of E(2), and suggest that pre-clinical and clinical development of polyamine analogues might require special precautions and selection of sensitive subpopulation of patients.
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Affiliation(s)
- Irina Nayvelt
- Department of Medicine and Cancer Institute of New Jersey, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
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Sun Y, Liu JH, Jin L, Lin SM, Yang Y, Sui YX, Shi H. Over-expression of the Beclin1 gene upregulates chemosensitivity to anti-cancer drugs by enhancing therapy-induced apoptosis in cervix squamous carcinoma CaSki cells. Cancer Lett 2010; 294:204-10. [DOI: 10.1016/j.canlet.2010.02.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 01/27/2010] [Accepted: 02/01/2010] [Indexed: 11/16/2022]
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17
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Sivridis E, Koukourakis MI, Zois CE, Ledaki I, Ferguson DJP, Harris AL, Gatter KC, Giatromanolaki A. LC3A-positive light microscopy detected patterns of autophagy and prognosis in operable breast carcinomas. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:2477-89. [PMID: 20382705 DOI: 10.2353/ajpath.2010.090049] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autophagy is a self-degradation mechanism by which cells recycle their own cytoplasmic constituents and dispose of excess or defective organelles after starvation and oxygen deprivation. An antibody to the microtubule-associated protein 1 light chain 3 (LC3A), recognizing both the soluble (LC3A-I) and the membrane-bound form (LC3A-II) of the protein, was used to detect autophagic activity in 102 breast carcinomas. Three distinct patterns were recognized: (1) diffuse cytoplasmic, (2) cytoplasmic/juxta-nuclear, and (3) "stone-like" pattern--dense, rounded, amorphous structures, 5 microm on average, typically enclosed within cytoplasmic vacuoles. The diffuse cytoplasmic pattern showed a direct association with estrogen and progesterone receptor expression. The juxta-nuclear pattern indicated a similar association with hormone receptors, an inverse association with tumor size, and a favorable prognosis. By contrast, an increased number of stone-like structures, probably representing an excessive autophagic response, was related to high-grade tumors and a less favorable outcome. Interestingly, 60 additional epithelial tumors of nonbreast origin disclosed identical autophagic patterns, and so did MDA231 breast cancer xenografts and HCT116 colon tumor spheroids (also analyzed by electron microscopy). Moreover, MCF-7 human breast cancer cell lines confirmed induction of LC3A by anoxia and Thapsigargin. It is concluded that autophagy can be readily recognized in breast carcinomas by light microscopy, after immunohistochemical staining with LC3A, but the significance of the various patterns expressed would need further evaluation.
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Affiliation(s)
- Efthimios Sivridis
- Department of Pathology, Democritus University of Thrace and University General Hospital of Alexandroupolis, Alexandroupolis, Greece
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Li Z, Chen B, Wu Y, Jin F, Xia Y, Liu X. Genetic and epigenetic silencing of the beclin 1 gene in sporadic breast tumors. BMC Cancer 2010; 10:98. [PMID: 20230646 PMCID: PMC2858113 DOI: 10.1186/1471-2407-10-98] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Accepted: 03/16/2010] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Beclin 1, an important autophagy-related protein in human cells, is involved in cell death and cell survival. Beclin 1 mapped to human chromosome 17q21. It is widely expressed in normal mammary epithelial cells. Although down-regulated expression with mono-allelic deletions of beclin 1 gene was frequently observed in breast tumors, whether there was other regulatory mechanism of beclin 1 was to be investigated. We studied the expression of beclin 1 and explored the possible regulatory mechanisms on its expression in breast tumors. METHODS 20 pairs of tumors and adjacent normal tissues from patients with sporadic breast invasive ductal cancer (IDCs) were collected. The mRNA expression of beclin 1 was detected by real-time quantitative RT-PCR. Loss of heterozygosity (LOH) was determined by real-time quantitative PCR and microsatellite methods. The protein expression of beclin 1, p53, BRCA1 and BRCA2 was assessed by immunohistochemistry. CpG islands in 5' genomic region of beclin 1 gene were identified using MethylPrimer Program. Sodium bisulfite sequencing was used in examining the methylation status of each CpG island. RESULTS Decreased beclin 1 mRNA expression was detected in 70% of the breast tumors, and the protein levels were co-related to the mRNA levels. Expression of beclin 1 mRNA was demonstrated to be much higher in the BRCA1 positive tumors than that in the BRCA1 negative ones. Loss of heterozygosity was detected in more than 45% of the breast tumors, and a dense cluster of CpG islands was found from the 5' end to the intron 2 of the beclin 1 gene. Methylation analysis showed that the promoter and the intron 2 of beclin 1 were aberrantly methylated in the tumors with decreased expression. CONCLUSIONS These data indicated that LOH and aberrant DNA methylation might be the possible reasons of the decreased expression of beclin 1 in the breast tumors. The findings here shed some new light on the regulatory mechanisms of beclin 1 in breast cancer.
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Affiliation(s)
- Zidong Li
- Institute of Biomedical Informatics, School of Medicine, Tsinghua University, Beijing, PR China
- Department of Biological Science and Biotechnology, Tsinghua University, Beijing, PR China
- Ministry of Education Key Laboratory of Bioinformatics, Tsinghua University, Beijing, PR China
| | - Bo Chen
- Department of Surgical Oncology, The First Affiliated Hospital, China Medical University, Shenyang, PR China
| | - Yiqing Wu
- Institute of Biomedical Informatics, School of Medicine, Tsinghua University, Beijing, PR China
- Department of Biological Science and Biotechnology, Tsinghua University, Beijing, PR China
- Ministry of Education Key Laboratory of Bioinformatics, Tsinghua University, Beijing, PR China
| | - Feng Jin
- Department of Surgical Oncology, The First Affiliated Hospital, China Medical University, Shenyang, PR China
| | - Yongjing Xia
- Institute of Biomedical Informatics, School of Medicine, Tsinghua University, Beijing, PR China
- Department of Biological Science and Biotechnology, Tsinghua University, Beijing, PR China
- Ministry of Education Key Laboratory of Bioinformatics, Tsinghua University, Beijing, PR China
| | - Xiangjun Liu
- Institute of Biomedical Informatics, School of Medicine, Tsinghua University, Beijing, PR China
- Department of Biological Science and Biotechnology, Tsinghua University, Beijing, PR China
- Ministry of Education Key Laboratory of Bioinformatics, Tsinghua University, Beijing, PR China
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Beclin-1 expression is a predictor of clinical outcome in patients with esophageal squamous cell carcinoma and correlated to hypoxia-inducible factor (HIF)-1alpha expression. Pathol Oncol Res 2010; 15:487-93. [PMID: 19130303 PMCID: PMC2791489 DOI: 10.1007/s12253-008-9143-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 12/16/2008] [Indexed: 02/05/2023]
Abstract
In the present study, we examined the relationship between Beclin-1 expression and HIF-1α expression in esophageal squamous cell carcinoma(ESCC). There was a loss of Beclin-1 protein expression in 33% of ESCCs. Beclin-1 expression significantly correlated with depth of invasion, lymph node metastasis and clinical stage. Among the 54 patients, The survival rate of the Beclin-1-positive group was better than that of the Beclin-1-negative group. Twenty-five of the 54 (46%) tumor specimens showed high levels of HIF-1α immunoreactivity. Beclin-1 expression was associated with HIF-1α expression. The survival rate of patients with Beclin-1-positive and HIF-1α-low tumors was significantly higher than that of the other groups. These results suggest that Beclin-1 and HIF-1α expression are important determinants of survival in ESCCs.
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20
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Deoxycholate, an endogenous cytotoxin/genotoxin, induces the autophagic stress-survival pathway: implications for colon carcinogenesis. J Toxicol 2009; 2009:785907. [PMID: 20130808 PMCID: PMC2814131 DOI: 10.1155/2009/785907] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 01/25/2009] [Accepted: 02/24/2009] [Indexed: 01/09/2023] Open
Abstract
We report that deoxycholate (DOC), a hydrophobic bile acid associated with a high-fat diet, activates the autophagic pathway in non-cancer colon epithelial cells (NCM-460), and that this activation contributes to cell survival. The DOC-induced increase in autophagy was documented by an increase in autophagic vacuoles (detected using transmission electron microscopy, increased levels of LC3-I and LC3-II (western blotting), an increase in acidic vesicles (fluorescence spectroscopy of monodansycadaverine and lysotracker red probes), and increased expression of the autophagic protein, beclin-1 (immunohistochemistry/western blotting). The DOC-induced increase in beclin-1 expression was ROS-dependent. Rapamycin (activator of autophagy) pre-treatment of NCM-460 cells significantly (P < .05) decreased, and 3-MA (inhibitor of autophagy) significantly (P < .05) increased the cell loss caused by DOC treatment, alone. Rapamycin pre-treatment of the apoptosis-resistant colon cancer cell line, HCT-116RC (developed in our laboratory), resulted in a significant decrease in DOC-induced cell death. Bafilomycin A(1) and hydroxychloroquine (inhibitors of the autophagic process) increased the DOC-induced percentage of apoptotic cells in HCT-116RC cells. It was concluded that the activation of autophagy by DOC has important implications for colon carcinogenesis and for the treatment of colon cancer in conjunction with commonly used chemotherapeutic agents.
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Sun Y, Zhang J, Peng ZL. Beclin1 Induces Autophagy and its Potential Contributions to Sensitizes SiHa Cells to Carboplatin Therapy. Int J Gynecol Cancer 2009; 19:772-6. [DOI: 10.1111/igc.0b013e31819d7d10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Abstract
Recently, autophagy has emerged as a critical process in the control of T-cell homeostasis. Given the pivotal role of NF-kappaB in the signaling events of T cells, we have analyzed and unveiled a conserved NF-kappaB binding site in the promoter of the murine and human BECN1 autophagic gene (Atg6). Accordingly, we demonstrate that the NF-kappaB family member p65/RelA upregulates BECN1 mRNA and protein levels in different cellular systems. Moreover, p65-mediated upregulation of BECN1 is coupled to increased autophagy. The newly identified kappaB site in the BECN1 promoter specifically interacts with p65 both in vitro and in living Jurkat cells upon phorbol myristate acetate (PMA)-ionomycin stimulation, where p65 induction is coupled to BECN1 upregulation and autophagy induction. Finally, anti-CD3- and PMA-ionomycin-mediated activation of T-cell receptor signaling in peripheral T cells from lymph nodes of healthy mice results in an upregulation of BECN1 expression that can be blocked by the NF-kappaB inhibitor BAY 11-7082. Altogether, these data suggest that autophagy could represent a novel route modulated by p65 to regulate cell survival and control T-cell homeostasis.
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Abstract
BH3 domains were originally discovered in the context of apoptosis regulators and they mediate binding of proapoptotic Bcl-2 family members to antiapoptotic Bcl-2 family members. Yet, recent studies indicate that BH3 domains do not function uniquely in apoptosis regulation; they also function in the regulation of another critical pathway involved in cellular and tissue homeostasis called autophagy. Antiapoptotic Bcl-2 homologs downregulate autophagy through interactions with the essential autophagy effector and haploinsufficient tumor suppressor, Beclin 1. Beclin 1 contains a BH3 domain, similar to that of Bcl-2 proteins, which is necessary and sufficient for binding to antiapoptotic Bcl-2 homologs and required for Bcl-2-mediated inhibition of autophagy. This review will summarize the evidence that the BH3 domain of Beclin 1 serves as a key structural motif that enables Bcl-2 to function not only as an antiapoptotic protein, but also as an antiautophagy protein.
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Affiliation(s)
- S Sinha
- Department of Chemistry, Biochemistry and Molecular Biology, North Dakota State University, Fargo, ND, USA
| | - B Levine
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Igoudjil A, Massart J, Begriche K, Descatoire V, Robin MA, Fromenty B. High concentrations of stavudine impair fatty acid oxidation without depleting mitochondrial DNA in cultured rat hepatocytes. Toxicol In Vitro 2008; 22:887-98. [DOI: 10.1016/j.tiv.2008.01.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 01/11/2008] [Accepted: 01/11/2008] [Indexed: 11/15/2022]
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Ahn CH, Jeong EG, Lee JW, Kim MS, Kim SH, Kim SS, Yoo NJ, Lee SH. Expression of beclin-1, an autophagy-related protein, in gastric and colorectal cancers. APMIS 2008; 115:1344-9. [PMID: 18184403 DOI: 10.1111/j.1600-0463.2007.00858.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Autophagy plays important roles in both cell death and cell survival. Beclin-1, a key regulator of autophagy formation, has been considered as a haploinsufficient tumor suppressor. Loss of expression or point mutation could serve as a mechanism of loss of beclin-1 tumor suppressor function in cancers. However, our recent study revealed that point mutation of the beclin-1 gene is a rare event in common human cancers. In this study we investigated beclin-1 protein expression in 103 colorectal and 60 gastric carcinoma tissues by immunohistochemistry using a tissue microarray approach. In the cancers, expression of beclin-1 was detected in 95% of the colorectal carcinomas and 83% of the gastric carcinomas. In contrast, normal mucosal cells of both stomach and colon showed no or very weak expression of beclin-1. There was no significant association of beclin-1 expression with clinocopathologic characteristics, including invasion, metastasis and stage. The beclin-1 expression of colorectal and gastric cancers in the present study is quite in contrast to that of the breast cancers in the previous study, which showed a decreased beclin-1 expression in breast cancer cells compared to normal breast cells. Our data indicate that beclin-1 inactivation by loss of expression may not occur in colorectal and gastric cancers. Rather, increased expression of beclin-1 in the malignant colorectal and gastric epithelial cells compared to their normal mucosal epithelial cells suggests that neo-expression of beclin-1 may play a role in both colorectal and gastric tumorigenesis.
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Affiliation(s)
- Chang Hyeok Ahn
- Department of Pathology, College of Medicine, The Catholic Unviersity of Korea, Seoul, Korea
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Cao Y, Klionsky DJ. Physiological functions of Atg6/Beclin 1: a unique autophagy-related protein. Cell Res 2007; 17:839-49. [PMID: 17893711 DOI: 10.1038/cr.2007.78] [Citation(s) in RCA: 443] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The most striking morphological feature of eukaryotic cells is the presence of various membrane-enclosed compartments. These compartments, including organelles and transient transport intermediates, are not static. Rather, dynamic exchange of proteins and membrane is needed to maintain cellular homeostasis. One of the most dramatic examples of membrane mobilization is seen during the process of macroautophagy. Macroautophagy is the primary cellular pathway for degradation of long-lived proteins and organelles. In response to environmental cues, such as starvation or other types of stress, the cell produces a unique membrane structure, the phagophore. The phagophore sequesters cytoplasm as it forms a double-membrane cytosolic vesicle, an autophagosome. Upon completion, the autophagosome fuses with a lysosome or a vacuole in yeast, which delivers hydrolases that break down the inner autophagosome membrane along with its cargo, and the resulting macromolecules are released back into the cytosol for reuse. Autophagy is therefore a recycling process, allowing cells to survive periods of nutrient limitation; however, it has a wider physiological role, participating in development and aging, and also in protection against pathogen invasion, cancer and certain neurodegenerative diseases. In many cases, the role of autophagy is identified through studies of an autophagy-related protein, Atg6/Beclin 1. This protein is part of a lipid kinase complex, and recent studies suggest that it plays a central role in coordinating the cytoprotective function of autophagy and in opposing the cellular death process of apoptosis. Here, we summarize our current knowledge of Atg6/Beclin 1 in different model organisms and its unique function in the cell.
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Affiliation(s)
- Yang Cao
- Department of Molecular, Cellular and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
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Abstract
We have previously reported that immortalized human hepatocytes (IHH) support the generation of infectious hepatitis C virus (HCV) genotype 1a (clone H77). In the present study, we have investigated the growth of HCV genotype 1a (clone H77) through serial passages and accompanying changes in IHH in response to infection. Eleven serial passages of HCV genotype 1a (clone H77) in IHH were completed. Virus replication was ascertained from the presence of HCV-specific sequences, the detection of core antigen, the virus genome copy number, and the virus titer in IHH culture fluid. Electron microscopy suggested that HCV infection induces autophagic vacuole formation in IHH. Fluorescence microscopy displayed localization of autophagic markers, microtubule-associated protein-1 light chain-3 and Apg5, on the vacuoles of HCV-infected hepatocytes. Taken together, our results suggested that HCV genotype 1a (clone H77) can be serially passaged in IHH and that HCV infection induces an autophagic response in hepatocytes.
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