1
|
Zhang Q, Feng W, Wang Q, Wang J, Chai L, Chen Y, Wang Y, Liu J, Li M, Xie X. PPARγ activation inhibits PDGF-induced pulmonary artery smooth muscle cell proliferation and migration by modulating TERT. Biomed Pharmacother 2022; 152:113233. [PMID: 35689861 DOI: 10.1016/j.biopha.2022.113233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/27/2022] [Accepted: 06/01/2022] [Indexed: 12/01/2022] Open
Abstract
Vascular remodeling is a significant feature of pulmonary artery hypertension (PAH), and is characterized by abnormal proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). Telomerase reverse transcriptase (TERT), as a determining factor for controlling telomerase activity, has been proven to be associated with cell proliferation. This study aims to explore whether TERT mediates the proliferation and migration of PASMCs and the underlying molecular mechanism. Primary PASMCs from Sprague-Dawley (SD) rats were used in this experiment. Cell proliferation and migration were evaluated by Cell Counting Kit-8, EdU incorporation assay and transwell assay, respectively. Telomerase activity was assessed with a rat TE ELISA kit. Small interfering RNA (siRNA) transfection was conducted to silence c-MYC expression. The protein levels of p-Akt, c-MYC, PPARγ and TERT were determined through western blotting. Our work demonstrates that PDGF upregulated TERT expression and telomerase activation by activating Akt and upregulating of c-MYC in PASMCs. Inhibition of Akt with LY294002, knockdown of c-MYC by siRNA or suppression of telomerase activity with BIBR1532 repressed PDGF-induced PASMC proliferation and migration. Furthermore, activation of peroxisome proliferator-activated receptor γ (PPARγ) with pioglitazone suppressed PDGF-induced TERT expression and telomerase activation, leading to inhibition of PASMC proliferation and migration.
Collapse
Affiliation(s)
- Qianqian Zhang
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Wei Feng
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Qingting Wang
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Jian Wang
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Limin Chai
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Yuqian Chen
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Yan Wang
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Jin Liu
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Manxiang Li
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Xinming Xie
- Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
| |
Collapse
|
2
|
Prochownik EV, Wang H. Normal and Neoplastic Growth Suppression by the Extended Myc Network. Cells 2022; 11:747. [PMID: 35203395 PMCID: PMC8870482 DOI: 10.3390/cells11040747] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/09/2022] [Accepted: 02/15/2022] [Indexed: 12/20/2022] Open
Abstract
Among the first discovered and most prominent cellular oncogenes is MYC, which encodes a bHLH-ZIP transcription factor (Myc) that both activates and suppresses numerous genes involved in proliferation, energy production, metabolism and translation. Myc belongs to a small group of bHLH-ZIP transcriptional regulators (the Myc Network) that includes its obligate heterodimerization partner Max and six "Mxd proteins" (Mxd1-4, Mnt and Mga), each of which heterodimerizes with Max and largely opposes Myc's functions. More recently, a second group of bHLH-ZIP proteins (the Mlx Network) has emerged that bears many parallels with the Myc Network. It is comprised of the Myc-like factors ChREBP and MondoA, which, in association with the Max-like member Mlx, regulate smaller and more functionally restricted repertoires of target genes, some of which are shared with Myc. Opposing ChREBP and MondoA are heterodimers comprised of Mlx and Mxd1, Mxd4 and Mnt, which also structurally and operationally link the two Networks. We discuss here the functions of these "Extended Myc Network" members, with particular emphasis on their roles in suppressing normal and neoplastic growth. These roles are complex due to the temporal- and tissue-restricted expression of Extended Myc Network proteins in normal cells, their regulation of both common and unique target genes and, in some cases, their functional redundancy.
Collapse
Affiliation(s)
- Edward V. Prochownik
- Division of Hematology/Oncology, The Department of Pediatrics, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA;
- The Department of Microbiology and Molecular Genetics, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
- The Hillman Cancer Center of UPMC, Pittsburgh, PA 15224, USA
- The Pittsburgh Liver Research Center, Pittsburgh, PA 15224, USA
| | - Huabo Wang
- Division of Hematology/Oncology, The Department of Pediatrics, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA;
| |
Collapse
|
3
|
Zhao L, Han X, Lu J, McEachern D, Wang S. A highly potent PROTAC androgen receptor (AR) degrader ARD-61 effectively inhibits AR-positive breast cancer cell growth in vitro and tumor growth in vivo. Neoplasia 2020; 22:522-532. [PMID: 32928363 PMCID: PMC7498667 DOI: 10.1016/j.neo.2020.07.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/28/2020] [Accepted: 07/02/2020] [Indexed: 12/21/2022]
Abstract
The androgen receptor (AR) has been found to be expressed in the majority of human breast cancer and AR antagonists, such as enzalutamide, have shown promising clinical activity in AR-positive (AR+) breast cancer. We have recently reported the discovery of a highly potent PROTAC AR degrader, ARD-61. In this study, we evaluated ARD-61 for its therapeutic potential and mechanism of action in breast cancer models in vitro and in vivo. ARD-61 potently and effectively induces AR degradation in AR+ breast cancer cell lines and is much more potent than enzalutamide in inhibition of cell growth and induction of cell cycle arrest and/or apoptosis. ARD-61 effectively induces complete AR degradation in xenograft tumor tissue and is more effective than enzalutamide in achieving tumor growth inhibition in the MDA-MB-453 xenograft model in mice. Our study provides strong preclinical rationale to develop AR degraders for the treatment of AR+ human breast cancer.
Collapse
Affiliation(s)
- Lijie Zhao
- School of Pharmaceutical Sciences and Institute of Drug Discovery & Development, Zhengzhou University, Zhengzhou 450001, China; Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, United States
| | - Xin Han
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, United States
| | - Jianfeng Lu
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, United States
| | - Donna McEachern
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, United States
| | - Shaomeng Wang
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States; Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, United States; Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, United States; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, United States.
| |
Collapse
|
4
|
Strassheim D, Karoor V, Nijmeh H, Weston P, Lapel M, Schaack J, Sullivan T, Dempsey EC, Stenmark KR, Gerasimovskaya E. c-Jun, Foxo3a, and c-Myc Transcription Factors are Key Regulators of ATP-Mediated Angiogenic Responses in Pulmonary Artery Vasa Vasorum Endothelial Cells. Cells 2020; 9:cells9020416. [PMID: 32054096 PMCID: PMC7072142 DOI: 10.3390/cells9020416] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 12/14/2022] Open
Abstract
Angiogenic vasa vasorum (VV) expansion plays an essential role in the pathogenesis of hypoxia-induced pulmonary hypertension (PH), a cardiovascular disease. We previously showed that extracellular ATP released under hypoxic conditions is an autocrine/paracrine, the angiogenic factor for pulmonary artery (PA) VV endothelial cells (VVECs), acting via P2Y purinergic receptors (P2YR) and the Phosphoinositide 3-kinase (PI3K)-Akt-Mammalian Target of Rapamycin (mTOR) signaling. To further elucidate the molecular mechanisms of ATP-mediated VV angiogenesis, we determined the profile of ATP-inducible transcription factors (TFs) in VVECs using a TranSignal protein/DNA array. C-Jun, c-Myc, and Foxo3 were found to be upregulated in most VVEC populations and formed nodes connecting several signaling networks. siRNA-mediated knockdown (KD) of these TFs revealed their critical role in ATP-induced VVEC angiogenic responses and the regulation of downstream targets involved in tissue remodeling, cell cycle control, expression of endothelial markers, cell adhesion, and junction proteins. Our results showed that c-Jun was required for the expression of ATP-stimulated angiogenic genes, c-Myc was repressive to anti-angiogenic genes, and Foxo3a predominantly controlled the expression of anti-apoptotic and junctional proteins. The findings from our study suggest that pharmacological targeting of the components of P2YR-PI3K-Akt-mTOR axis and specific TFs reduced ATP-mediated VVEC angiogenic response and may have a potential translational significance in attenuating pathological vascular remodeling.
Collapse
Affiliation(s)
- Derek Strassheim
- Department of Medicine Cardiovascular and Pulmonary Research Laboratory, University of Colorado Denver, Aurora, CO 80045, USA; (D.S.); (V.K.); (T.S.); (E.C.D.); (K.R.S.)
| | - Vijaya Karoor
- Department of Medicine Cardiovascular and Pulmonary Research Laboratory, University of Colorado Denver, Aurora, CO 80045, USA; (D.S.); (V.K.); (T.S.); (E.C.D.); (K.R.S.)
| | - Hala Nijmeh
- Department of Pediatrics, Division of Critical Care Medicine, University of Colorado Denver, Aurora, CO 80045, USA; (H.N.); (P.W.); (M.L.)
| | - Philip Weston
- Department of Pediatrics, Division of Critical Care Medicine, University of Colorado Denver, Aurora, CO 80045, USA; (H.N.); (P.W.); (M.L.)
| | - Martin Lapel
- Department of Pediatrics, Division of Critical Care Medicine, University of Colorado Denver, Aurora, CO 80045, USA; (H.N.); (P.W.); (M.L.)
| | - Jerome Schaack
- Department of Microbiology, University of Colorado Denver, Aurora, CO 80045, USA;
| | - Timothy Sullivan
- Department of Medicine Cardiovascular and Pulmonary Research Laboratory, University of Colorado Denver, Aurora, CO 80045, USA; (D.S.); (V.K.); (T.S.); (E.C.D.); (K.R.S.)
| | - Edward C. Dempsey
- Department of Medicine Cardiovascular and Pulmonary Research Laboratory, University of Colorado Denver, Aurora, CO 80045, USA; (D.S.); (V.K.); (T.S.); (E.C.D.); (K.R.S.)
- Rocky Mountain Regional VA Medical Center, Aurora, CO 80045, USA
| | - Kurt R. Stenmark
- Department of Medicine Cardiovascular and Pulmonary Research Laboratory, University of Colorado Denver, Aurora, CO 80045, USA; (D.S.); (V.K.); (T.S.); (E.C.D.); (K.R.S.)
- Department of Pediatrics, Division of Critical Care Medicine, University of Colorado Denver, Aurora, CO 80045, USA; (H.N.); (P.W.); (M.L.)
| | - Evgenia Gerasimovskaya
- Department of Medicine Cardiovascular and Pulmonary Research Laboratory, University of Colorado Denver, Aurora, CO 80045, USA; (D.S.); (V.K.); (T.S.); (E.C.D.); (K.R.S.)
- Department of Pediatrics, Division of Critical Care Medicine, University of Colorado Denver, Aurora, CO 80045, USA; (H.N.); (P.W.); (M.L.)
- Correspondence: ; Tel.: +1-303-724-5614
| |
Collapse
|
5
|
Xie R, Tuo B, Yang S, Chen XQ, Xu J. Calcium-sensing receptor bridges calcium and telomerase reverse transcriptase in gastric cancers via Akt. Clin Transl Oncol 2019; 22:1023-1032. [PMID: 31650467 DOI: 10.1007/s12094-019-02226-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 10/03/2019] [Indexed: 01/27/2023]
Abstract
PURPOSE Human telomerase reverse transcriptase (hTERT) and calcium-sensing receptor (CaSR) act as an oncogene in gastric cancers, however, their relationship in the progression of gastric cancers is yet to be elucidated. Herein, we aimed to access the potential interaction between hTERT and CaSR in the development of gastric cancers. METHODS The clinical data of 41 patients with gastric cancers were analyzed regarding the expressions of hTERT and CaSR by immunohistochemistry. Among them, five patients' specimens were also analyzed by Western blotting. The regulation of calcium on the expression level of hTERT and the possible underlying mechanism via CaSR were explored in gastric cancer cell lines MKN45 and SGC-7901. RESULTS Both hTERT and CaSR were increased and positively correlated in human gastric cancers, which also occurs in gastric cancer cells MKN45 and SGC-7901. Calcium induced hTERT expression at the transcriptional level in a CaSR-dependent manner followed by an increase in telomerase activity, as either a CaSR shRNA or the CaSR antagonist NPS2143 abolished the calcium-mediated regulation of hTERT and telomerase activity. Further studies showed that CaSR-mediated cytosolic calcium rise followed by Akt activation was involved in the regulation of hTERT by extracellular calcium. Finally, neither CaSR overexpression nor shRNA-mediated CaSR downregulation had an effect on the expression level of hTERT. CONCLUSIONS Our findings established a functional linkage between CaSR and hTERT in the development of gastric cancers and CaSR-hTERT coupling might serve as a novel target for therapeutic strategy against human gastric cancers.
Collapse
Affiliation(s)
- R Xie
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563000, China.
| | - B Tuo
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563000, China
| | - S Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China
| | - X-Q Chen
- Department of Neurosciences, School of Medicine, University of California, San Diego, CA, 92093, USA.
| | - J Xu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563000, China.
| |
Collapse
|
6
|
|
7
|
Zhang F, Cheng D, Wang S, Zhu J. Human Specific Regulation of the Telomerase Reverse Transcriptase Gene. Genes (Basel) 2016; 7:genes7070030. [PMID: 27367732 PMCID: PMC4962000 DOI: 10.3390/genes7070030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/15/2016] [Accepted: 06/17/2016] [Indexed: 12/19/2022] Open
Abstract
Telomerase, regulated primarily by the transcription of its catalytic subunit telomerase reverse transcriptase (TERT), is critical for controlling cell proliferation and tissue homeostasis by maintaining telomere length. Although there is a high conservation between human and mouse TERT genes, the regulation of their transcription is significantly different in these two species. Whereas mTERT expression is widely detected in adult mice, hTERT is expressed at extremely low levels in most adult human tissues and cells. As a result, mice do not exhibit telomere-mediated replicative aging, but telomere shortening is a critical factor of human aging and its stabilization is essential for cancer development in humans. The chromatin environment and epigenetic modifications of the hTERT locus, the binding of transcriptional factors to its promoter, and recruitment of nucleosome modifying complexes all play essential roles in restricting its transcription in different cell types. In this review, we will discuss recent progress in understanding the molecular mechanisms of TERT regulation in human and mouse tissues and cells, and during cancer development.
Collapse
Affiliation(s)
- Fan Zhang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
| | - De Cheng
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
| | - Shuwen Wang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
| | - Jiyue Zhu
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
| |
Collapse
|
8
|
Peek GW, Tollefsbol TO. Down-regulation of hTERT and Cyclin D1 transcription via PI3K/Akt and TGF-β pathways in MCF-7 Cancer cells with PX-866 and Raloxifene. Exp Cell Res 2016; 344:95-102. [PMID: 27017931 DOI: 10.1016/j.yexcr.2016.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/16/2016] [Accepted: 03/22/2016] [Indexed: 11/26/2022]
Abstract
Human telomerase reverse transcriptase (hTERT) is the catalytic and limiting component of telomerase and also a transcription factor. It is critical to the integrity of the ends of linear chromosomes and to the regulation, extent and rate of cell cycle progression in multicellular eukaryotes. The level of hTERT expression is essential to a wide range of bodily functions and to avoidance of disease conditions, such as cancer, that are mediated in part by aberrant level and regulation of cell cycle proliferation. Value of a gene in regulation depends on its ability to both receive input from multiple sources and transmit signals to multiple effectors. The expression of hTERT and the progression of the cell cycle have been shown to be regulated by an extensive network of gene products and signaling pathways, including the PI3K/Akt and TGF-β pathways. The PI3K inhibitor PX-866 and the competitive estrogen receptor ligand raloxifene have been shown to modify progression of those pathways and, in combination, to decrease proliferation of estrogen receptor positive (ER+) MCF-7 breast cancer cells. We found that combinations of modulators of those pathways decreased not only hTERT transcription but also transcription of additional essential cell cycle regulators such as Cyclin D1. By evaluating known expression profile signatures for TGF-β pathway diversions, we confirmed additional genes such as heparin-binding epidermal growth factor-like growth factor (HB EGF) by which those pathways and their perturbations may also modify cell cycle progression.
Collapse
Affiliation(s)
- Gregory W Peek
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Trygve O Tollefsbol
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA; Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, AL, USA; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, USA; Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
9
|
Heeg S. Variations in telomere maintenance and the role of telomerase inhibition in gastrointestinal cancer. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2015; 8:171-80. [PMID: 26675332 PMCID: PMC4675635 DOI: 10.2147/pgpm.s52808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Immortalization is an important step toward the malignant transformation of human cells and is critically dependent upon telomere maintenance. There are two known mechanisms to maintain human telomeres. The process of telomere maintenance is either mediated through activation of the enzyme telomerase or through an alternative mechanism of telomere lengthening called ALT. While 85% of all human tumors show reactivation of telomerase, the remaining 15% are able to maintain telomeres via ALT. The therapeutic potential of telomerase inhibitors is currently investigated in a variety of human cancers. Gastrointestinal tumors are highly dependent on telomerase as a mechanism of telomere maintenance, rendering telomeres as well as telomerase potential targets for cancer therapy. This article focuses on the molecular mechanisms of telomere biology and telomerase activation in gastrointestinal cancers and reviews strategies of telomerase inhibition and their potential therapeutic use in these tumor entities.
Collapse
Affiliation(s)
- Steffen Heeg
- Department of Medicine II, Gastroenterology, Hepatology, Endocrinology, and Infectious Diseases, Medical Center - University of Freiburg, Freiburg, Germany
| |
Collapse
|
10
|
Yaswen P, MacKenzie KL, Keith WN, Hentosh P, Rodier F, Zhu J, Firestone GL, Matheu A, Carnero A, Bilsland A, Sundin T, Honoki K, Fujii H, Georgakilas AG, Amedei A, Amin A, Helferich B, Boosani CS, Guha G, Ciriolo MR, Chen S, Mohammed SI, Azmi AS, Bhakta D, Halicka D, Niccolai E, Aquilano K, Ashraf SS, Nowsheen S, Yang X. Therapeutic targeting of replicative immortality. Semin Cancer Biol 2015; 35 Suppl:S104-S128. [PMID: 25869441 PMCID: PMC4600408 DOI: 10.1016/j.semcancer.2015.03.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 03/06/2015] [Accepted: 03/13/2015] [Indexed: 12/15/2022]
Abstract
One of the hallmarks of malignant cell populations is the ability to undergo continuous proliferation. This property allows clonal lineages to acquire sequential aberrations that can fuel increasingly autonomous growth, invasiveness, and therapeutic resistance. Innate cellular mechanisms have evolved to regulate replicative potential as a hedge against malignant progression. When activated in the absence of normal terminal differentiation cues, these mechanisms can result in a state of persistent cytostasis. This state, termed “senescence,” can be triggered by intrinsic cellular processes such as telomere dysfunction and oncogene expression, and by exogenous factors such as DNA damaging agents or oxidative environments. Despite differences in upstream signaling, senescence often involves convergent interdependent activation of tumor suppressors p53 and p16/pRB, but can be induced, albeit with reduced sensitivity, when these suppressors are compromised. Doses of conventional genotoxic drugs required to achieve cancer cell senescence are often much lower than doses required to achieve outright cell death. Additional therapies, such as those targeting cyclin dependent kinases or components of the PI3K signaling pathway, may induce senescence specifically in cancer cells by circumventing defects in tumor suppressor pathways or exploiting cancer cells’ heightened requirements for telomerase. Such treatments sufficient to induce cancer cell senescence could provide increased patient survival with fewer and less severe side effects than conventional cytotoxic regimens. This positive aspect is countered by important caveats regarding senescence reversibility, genomic instability, and paracrine effects that may increase heterogeneity and adaptive resistance of surviving cancer cells. Nevertheless, agents that effectively disrupt replicative immortality will likely be valuable components of new combinatorial approaches to cancer therapy.
Collapse
Affiliation(s)
- Paul Yaswen
- Life Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA, United States.
| | - Karen L MacKenzie
- Children's Cancer Institute Australia, Kensington, New South Wales, Australia.
| | | | | | | | - Jiyue Zhu
- Washington State University College of Pharmacy, Pullman, WA, United States.
| | | | | | - Amancio Carnero
- Instituto de Biomedicina de Sevilla, HUVR, Consejo Superior de Investigaciones Cientificas, Universdad de Sevilla, Seville, Spain.
| | | | | | | | | | | | | | - Amr Amin
- United Arab Emirates University, Al Ain, United Arab Emirates; Cairo University, Cairo, Egypt
| | - Bill Helferich
- University of Illinois at Urbana Champaign, Champaign, IL, United States
| | | | - Gunjan Guha
- SASTRA University, Thanjavur, Tamil Nadu, India
| | | | - Sophie Chen
- Ovarian and Prostate Cancer Research Trust, Guildford, Surrey, United Kingdom
| | | | - Asfar S Azmi
- Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States
| | | | | | | | | | - S Salman Ashraf
- United Arab Emirates University, Al Ain, United Arab Emirates; Cairo University, Cairo, Egypt
| | | | - Xujuan Yang
- University of Illinois at Urbana Champaign, Champaign, IL, United States
| |
Collapse
|
11
|
Wang MC, Lee YH, Liao PC. Optimization of titanium dioxide and immunoaffinity-based enrichment procedures for tyrosine phosphopeptide using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Anal Bioanal Chem 2014; 407:1343-56. [PMID: 25486920 DOI: 10.1007/s00216-014-8352-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 11/06/2014] [Accepted: 11/17/2014] [Indexed: 01/25/2023]
Abstract
Tyrosine phosphorylation is an important regulator of signaling in cellular pathways, and dysregulated tyrosine phosphorylation causes several diseases. Mass spectrometry has revealed the importance of global phosphoproteomic characterization. Analysis of tyrosine phosphorylation by studying the mass-spectrometry (MS)-determined phosphoproteome remains difficult because of the relatively low abundance of tyrosine phosphoproteins. To effectively evaluate tyrosine-phosphopeptide enrichment and reduce ion suppression from non-phosphorylated peptides in MS analysis, three trypsin-digested BSA peptides and 14 standard phosphopeptides, including six tyrosine phosphopeptides, four serine phosphopeptides, and four threonine phosphopeptides, were subjected to titanium dioxide immunoaffinity-based enrichment and also to combined enrichment using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and liquid chromatography-mass spectrometry (LC-MS) analyses. The enrichment factors were evaluated to determine the efficiency of each enrichment procedure. Comparison of five optimized enrichment methods, including TiO2-based immunoaffinity purification in Tris and MOPS buffer systems, TiO2-immunoaffinity enrichment, and immunoaffinity-TiO2 enrichment for total tyrosine, serine and threonine phosphopeptides, revealed that the order of the enrichment factors for total tyrosine phosphopeptides is: (i) immunoaffinity-TiO2 (enrichment factor = 38,244), (ii) TiO2-immunoaffinity (enrichment factor = 24,987), (iii) TiO2 micro-column (enrichment factor = 10,305), (iv) immunoaffinity in Tris buffer system (enrichment factor = 1450), and (v) immunoaffinity in the MOPS buffer system (enrichment factor = 32). These results reveal that an alternative enrichment scheme before use of a TiO2 micro-column, using immunoaffinity 4G10 and PY99 antibody enrichment under optimized conditions, can provide greater selectivity for tyrosine-phosphopeptide enrichment.
Collapse
Affiliation(s)
- Ming-Chuan Wang
- Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan, 70428, Taiwan, Republic of China
| | | | | |
Collapse
|
12
|
Wu XQ, Huang C, He X, Tian YY, Zhou DX, He Y, Liu XH, Li J. Feedback regulation of telomerase reverse transcriptase: new insight into the evolving field of telomerase in cancer. Cell Signal 2013; 25:2462-8. [DOI: 10.1016/j.cellsig.2013.08.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 08/23/2013] [Indexed: 01/07/2023]
|
13
|
hTERT: Another brick in the wall of cancer cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2013; 752:119-128. [DOI: 10.1016/j.mrrev.2012.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/28/2012] [Accepted: 12/10/2012] [Indexed: 01/06/2023]
|
14
|
Ni M, Chen Y, Fei T, Li D, Lim E, Liu XS, Brown M. Amplitude modulation of androgen signaling by c-MYC. Genes Dev 2013; 27:734-48. [PMID: 23530127 DOI: 10.1101/gad.209569.112] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Androgen-stimulated growth of the molecular apocrine breast cancer subtype is mediated by an androgen receptor (AR)-regulated transcriptional program. However, the molecular details of this AR-centered regulatory network and the roles of other transcription factors that cooperate with AR in the network remain elusive. Here we report a positive feed-forward loop that enhances breast cancer growth involving AR, AR coregulators, and downstream target genes. In the absence of an androgen signal, TCF7L2 interacts with FOXA1 at AR-binding sites and represses the basal expression of AR target genes, including MYC. Direct AR regulation of MYC cooperates with AR-mediated activation of HER2/HER3 signaling. HER2/HER3 signaling increases the transcriptional activity of MYC through phosphorylation of MAD1, leading to increased levels of MYC/MAX heterodimers. MYC in turn reinforces the transcriptional activation of androgen-responsive genes. These results reveal a novel regulatory network in molecular apocrine breast cancers regulated by androgen and AR in which MYC plays a central role as both a key target and a cooperating transcription factor to drive oncogenic growth.
Collapse
Affiliation(s)
- Min Ni
- Division of Molecular and Cellular Oncology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Regulation of the human catalytic subunit of telomerase (hTERT). Gene 2012; 498:135-46. [PMID: 22381618 DOI: 10.1016/j.gene.2012.01.095] [Citation(s) in RCA: 199] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 01/29/2012] [Accepted: 01/30/2012] [Indexed: 12/12/2022]
Abstract
Over the past decade, there has been much interest in the regulation of telomerase, the enzyme responsible for maintaining the integrity of chromosomal ends, and its crucial role in cellular immortalization, tumorigenesis, and the progression of cancer. Telomerase activity is characterized by the expression of the telomerase reverse transcriptase (TERT) gene, suggesting that TERT serves as the major limiting agent for telomerase activity. Recent discoveries have led to characterization of various interactants that aid in the regulation of human TERT (hTERT), including numerous transcription factors; further supporting the pivotal role that transcription plays in both the expression and repression of telomerase. Several studies have suggested that epigenetic modulation of the hTERT core promoter region may provide an additional level of regulation. Although these studies have provided essential information on the regulation of hTERT, there has been ambiguity of the role of methylation within the core promoter region and the subsequent binding of various activating and repressive agents. As a result, we found it necessary to consolidate and summarize these recent developments and elucidate these discrepancies. In this review, we focus on the co-regulation of hTERT via transcriptional regulation, the presence or absence of various activators and repressors, as well as the epigenetic pathways of DNA methylation and histone modifications.
Collapse
|
16
|
Lüscher B. MAD1 and its life as a MYC antagonist: an update. Eur J Cell Biol 2011; 91:506-14. [PMID: 21917351 DOI: 10.1016/j.ejcb.2011.07.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/21/2011] [Accepted: 07/25/2011] [Indexed: 12/16/2022] Open
Abstract
The MYC/MAX/MAD network is of central importance for controlling cell physiology. The network is compiled of transcriptional regulators that form different heterodimers, which can either activate or repress the expression of target genes. Thus these proteins function as a molecular switch to control gene expression. MAD1, a member of this network, acts as a transcriptional repressor. It interacts with MAX to form the OFF position of the switch, antagonizing MYC/MAX complexes that define the ON position. MAD1 regulates cell proliferation and apoptosis through a number of target genes. In addition recent evidence indicates that the expression and activity of MAD1 are regulated at multiple levels. Here the recent developments are summarized, in comparison to MYC, of our understanding how the expression of the MAD1 gene and protein are controlled and what the functional consequences and downstream effectors of MAD1 are, which relay its activity as a transcriptional regulator.
Collapse
Affiliation(s)
- Bernhard Lüscher
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, 52057 Aachen, Germany.
| |
Collapse
|
17
|
Huang WC, Chen YJ, Li LY, Wei YL, Hsu SC, Tsai SL, Chiu PC, Huang WP, Wang YN, Chen CH, Chang WC, Chang WC, Chen AJE, Tsai CH, Hung MC. Nuclear translocation of epidermal growth factor receptor by Akt-dependent phosphorylation enhances breast cancer-resistant protein expression in gefitinib-resistant cells. J Biol Chem 2011; 286:20558-68. [PMID: 21487020 DOI: 10.1074/jbc.m111.240796] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Epidermal growth factor receptor (EGFR), an aberrantly overexpressed or activated receptor-tyrosine kinase in many cancers, plays a pivotal role in cancer progression and has been an attractive target for cancer therapy. Gefitinib and erlotinib, two EGFR-tyrosine kinase inhibitors, have been approved for non-small cell lung cancer. However, durable clinical efficacy of these EGFR inhibitors is severely limited by the emergence of acquired resistance. For example, the expression of breast cancer-resistant protein (BCRP/ABCG2) has been shown to confer acquired resistance of wild-type EGFR (wtEGFR)-expressing cancer cells to gefitinib. However, the underlying molecular mechanisms still remain unclear. Here, we show that wtEGFR expression is elevated in the nucleus of acquired gefitinib-resistant cancer cells. Moreover, nuclear translocation of EGFR requires phosphorylation at Ser-229 by Akt. In the nucleus, EGFR then targets the proximal promoter of BCRP/ABCG2 and thereby enhances its gene transcription. The nuclear EGFR-mediated BCRP/ABCG2 expression may contribute at least in part to the acquired resistance of wtEGFR-expressing cancer cells to gefitinib. Our findings shed light on the role of nuclear EGFR in the sensitivity of wtEGFR-expressing cancer cells to EGFR tyrosine kinase inhibitors and also deciphered a putative molecular mechanism contributing to gefitinib resistance through BCRP/ABCG2 expression.
Collapse
Affiliation(s)
- Wei-Chien Huang
- Center for Molecular Medicine, China Medical University Hospital, Taichung 404, Taiwan.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
The transposon-driven evolutionary origin and basis of histone deacetylase functions and limitations in disease prevention. Clin Epigenetics 2011; 2:97-112. [PMID: 22704332 PMCID: PMC3365375 DOI: 10.1007/s13148-011-0020-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 01/03/2011] [Indexed: 12/19/2022] Open
Abstract
Histone deacetylases (HDACs) are homologous to prokaryotic enzymes that removed acetyl groups from non-histone proteins before the evolution of eukaryotic histones. Enzymes inherited from prokaryotes or from a common ancestor were adapted for histone deacetylation, while useful deacetylation of non-histone proteins was selectively retained. Histone deacetylation served to prevent transcriptions with pathological consequences, including the expression of viral DNA and the deletion or dysregulation of vital genes by random transposon insertions. Viruses are believed to have evolved from transposons, with transposons providing the earliest impetus of HDAC evolution. Because of the wide range of genes potentially affected by transposon insertions, the range of diseases that can be prevented by HDACs is vast and inclusive. Repressive chromatin modifications that may prevent transcription also include methylation of selective lysine residues of histones H3 and H4 and the methylation of selective DNA cytosines following specific histone lysine methylation. Methylation and acetylation of individual histone residues are mutually exclusive. While transposons were sources of disease to be prevented by HDAC evolution, they were also the source of numerous and valuable coding and regulatory sequences recruited by “molecular domestication.” Those sequences contribute to evolved complex transcription regulation in which components with contradictory effects, such as HDACs and HATs, may be coordinated and complementary. Within complex transcription regulation, however, HDACs remain ineffective as defense against some critical infectious and non-infectious diseases because evolutionary compromises have rendered their activity transient.
Collapse
|
19
|
Yamaguchi H, Chen CT, Chou CK, Pal A, Bornmann W, Hortobagyi GN, Hung MC. Adenovirus 5 E1A enhances histone deacetylase inhibitors-induced apoptosis through Egr-1-mediated Bim upregulation. Oncogene 2010; 29:5619-29. [PMID: 20676141 DOI: 10.1038/onc.2010.295] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Histone deacetylase inhibitors (HDACi) are potent anti-cancer agents for variety of cancer types. Suberoylanilide hydroxamic acid (SAHA) has been approved as a drug to treat cutaneous T cell lymphoma, and the combination of HDACi and other agents have been actively tested in many clinical trials. Adenovirus 5 early region 1A (E1A) has been shown to exhibit high tumor suppressor activity, and gene therapy using E1A has been tested in clinical trials. Here, we showed that proapoptotic activity of HDACi was robustly enhanced by E1A in multiple cancer cells, but not in normal cells. Moreover, we showed that combination of E1A gene therapy and SAHA showed high therapeutic efficacy with low toxicity in vivo ovarian and breast xenograft models. SAHA downregulated Bcl-XL and upregulated proapoptotic BH3-only protein Bim, whose expression was further enhanced by E1A in cancer cells. These alterations of Bcl-2 family proteins were critical for apoptosis induced by the combination in cancer cells. SAHA enhanced acetylation of histone H3 in Bim promoter region, while E1A upregulated Egr-1, which was directly involved in Bim transactivation. Together, our results provide not only a novel insight into the mechanisms underlying anti-tumor activity of E1A, but also a rationale for the combined HDACi and E1A gene therapy in future clinical trials.
Collapse
Affiliation(s)
- H Yamaguchi
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | | | | | | | | | | |
Collapse
|