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Vemulapalli S, Hashemi M, Chen Y, Pramanik S, Bhakat KK, Lyubchenko YL. Nanoscale Interaction of Endonuclease APE1 with DNA. Int J Mol Sci 2024; 25:5145. [PMID: 38791183 PMCID: PMC11121393 DOI: 10.3390/ijms25105145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/17/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is involved in DNA repair and transcriptional regulation mechanisms. This multifunctional activity of APE1 should be supported by specific structural properties of APE1 that have not yet been elucidated. Herein, we applied atomic force microscopy (AFM) to characterize the interactions of APE1 with DNA containing two well-separated G-rich segments. Complexes of APE1 with DNA containing G-rich segments were visualized, and analysis of the complexes revealed the affinity of APE1 to G-rich DNA sequences, and their yield was as high as 53%. Furthermore, APE1 is capable of binding two DNA segments leading to the formation of loops in the DNA-APE1 complexes. The analysis of looped APE1-DNA complexes revealed that APE1 can bridge G-rich segments of DNA. The yield of loops bridging two G-rich DNA segments was 41%. Analysis of protein size in various complexes was performed, and these data showed that loops are formed by APE1 monomer, suggesting that APE1 has two DNA binding sites. The data led us to a model for the interaction of APE1 with DNA and the search for the specific sites. The implication of these new APE1 properties in organizing DNA, by bringing two distant sites together, for facilitating the scanning for damage and coordinating repair and transcription is discussed.
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Affiliation(s)
- Sridhar Vemulapalli
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA; (S.V.); (M.H.)
| | - Mohtadin Hashemi
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA; (S.V.); (M.H.)
- Department of Physics, Auburn University, Auburn, AL 36849-5318, USA
| | - Yingling Chen
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198-5805, USA; (Y.C.); (S.P.)
| | - Suravi Pramanik
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198-5805, USA; (Y.C.); (S.P.)
| | - Kishor K. Bhakat
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198-5805, USA; (Y.C.); (S.P.)
| | - Yuri L. Lyubchenko
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA; (S.V.); (M.H.)
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Pramanik S, Chen Y, Song H, Khutsishvili I, Marky LA, Ray S, Natarajan A, Singh P, Bhakat K. The human AP-endonuclease 1 (APE1) is a DNA G-quadruplex structure binding protein and regulates KRAS expression in pancreatic ductal adenocarcinoma cells. Nucleic Acids Res 2022; 50:3394-3412. [PMID: 35286386 PMCID: PMC8990529 DOI: 10.1093/nar/gkac172] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 02/14/2022] [Accepted: 03/08/2022] [Indexed: 11/12/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC), one of the most aggressive types of cancer, is characterized by aberrant activity of oncogenic KRAS. A nuclease-hypersensitive GC-rich region in KRAS promoter can fold into a four-stranded DNA secondary structure called G-quadruplex (G4), known to regulate KRAS expression. However, the factors that regulate stable G4 formation in the genome and KRAS expression in PDAC are largely unknown. Here, we show that APE1 (apurinic/apyrimidinic endonuclease 1), a multifunctional DNA repair enzyme, is a G4-binding protein, and loss of APE1 abrogates the formation of stable G4 structures in cells. Recombinant APE1 binds to KRAS promoter G4 structure with high affinity and promotes G4 folding in vitro. Knockdown of APE1 reduces MAZ transcription factor loading onto the KRAS promoter, thus reducing KRAS expression in PDAC cells. Moreover, downregulation of APE1 sensitizes PDAC cells to chemotherapeutic drugs in vitro and in vivo. We also demonstrate that PDAC patients' tissue samples have elevated levels of both APE1 and G4 DNA. Our findings unravel a critical role of APE1 in regulating stable G4 formation and KRAS expression in PDAC and highlight G4 structures as genomic features with potential application as a novel prognostic marker and therapeutic target in PDAC.
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Affiliation(s)
- Suravi Pramanik
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Yingling Chen
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Heyu Song
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Irine Khutsishvili
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Luis A Marky
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Sutapa Ray
- Hematology/Oncology Division, Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Amarnath Natarajan
- Eppley Institute for Research in Cancer and Allied Health, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Pankaj K Singh
- Eppley Institute for Research in Cancer and Allied Health, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kishor K Bhakat
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Beyond the Double-Strand Breaks: The Role of DNA Repair Proteins in Cancer Stem-Cell Regulation. Cancers (Basel) 2021; 13:cancers13194818. [PMID: 34638302 PMCID: PMC8508278 DOI: 10.3390/cancers13194818] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/22/2021] [Accepted: 09/22/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Cancer stem cells (CSCs) are a tumor cell population maintaining tumor growth and promoting tumor relapse if not wholly eradicated during treatment. CSCs are often equipped with molecular mechanisms making them resistant to conventional anti-cancer therapies whose curative potential depends on DNA damage-induced cell death. An elevated expression of some key DNA repair proteins is one of such defense mechanisms. However, new research reveals that the role of critical DNA repair proteins is extending far beyond the DNA repair mechanisms. This review discusses the diverse biological functions of DNA repair proteins in CSC maintenance and the adaptation to replication and oxidative stress, anti-cancer immune response, epigenetic reprogramming, and intracellular signaling mechanisms. It also provides an overview of their potential therapeutic targeting. Abstract Cancer stem cells (CSCs) are pluripotent and highly tumorigenic cells that can re-populate a tumor and cause relapses even after initially successful therapy. As with tissue stem cells, CSCs possess enhanced DNA repair mechanisms. An active DNA damage response alleviates the increased oxidative and replicative stress and leads to therapy resistance. On the other hand, mutations in DNA repair genes cause genomic instability, therefore driving tumor evolution and developing highly aggressive CSC phenotypes. However, the role of DNA repair proteins in CSCs extends beyond the level of DNA damage. In recent years, more and more studies have reported the unexpected role of DNA repair proteins in the regulation of transcription, CSC signaling pathways, intracellular levels of reactive oxygen species (ROS), and epithelial–mesenchymal transition (EMT). Moreover, DNA damage signaling plays an essential role in the immune response towards tumor cells. Due to its high importance for the CSC phenotype and treatment resistance, the DNA damage response is a promising target for individualized therapies. Furthermore, understanding the dependence of CSC on DNA repair pathways can be therapeutically exploited to induce synthetic lethality and sensitize CSCs to anti-cancer therapies. This review discusses the different roles of DNA repair proteins in CSC maintenance and their potential as therapeutic targets.
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Li W, Wang M, Chen Y, Chen C, Liu X, Sun X, Jing C, Xu L, Yan R, Li X, Song X. EtMIC3 and its receptors BAG1 and ENDOUL are essential for site-specific invasion of Eimeria tenella in chickens. Vet Res 2020; 51:90. [PMID: 32678057 PMCID: PMC7367391 DOI: 10.1186/s13567-020-00809-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 06/08/2020] [Indexed: 12/16/2022] Open
Abstract
Avian coccidian parasites exhibit a high degree of site specificity in different Eimeria species. Although the underlying mechanism is unclear, an increasing body of evidence suggests that site specificity is due to the interaction between microneme proteins (MICs) and their receptors on the surface of target host cells. In this study, the binding ability of E. tenella MICs (EtMICs) to different intestinal tissue was observed by immunofluorescence to identify the key surface molecule on the parasite responsible for the site specificity. Subsequently, we identified the corresponding host-cell receptors by yeast two-hybrid screening and glutathione-S-transferase pull-down experiments and the distribution of these receptors was observed by immunofluorescence in chicken intestinal tissues. Finally, we evaluated the efficacy of receptor antiserum against the infection of E. tenella in chickens. The results showed that EtMIC3 could only bind to the caecum while EtMIC1, EtMIC2, and EtAMA1 did not bind to any other intestinal tissues. Anti-serum to EtMIC3 was able to block the invasion of sporozoites with a blocking rate of 66.3%. The receptors for EtMIC3 were BCL2-associated athanogene 1 (BAG1) and Endonuclease polyU-specific-like (ENDOUL), which were mainly distributed in the caecum. BAG1 and ENDOUL receptor antiserum reduced weight loss and oocyst output following E. tenella infection, showing partial inhibition of E. tenella infection. These data elucidate the mechanism of site specificity for Eimeria infection and reveal a potential therapeutic avenue.
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Affiliation(s)
- Wenyu Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Mingyue Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Yufeng Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Chen Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Xiaoqian Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Xiaoting Sun
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Chuanxu Jing
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Lixin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Ruofeng Yan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Xiangrui Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Xiaokai Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
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5
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Wright G, Gassman NR. Transcriptional dysregulation of base excision repair proteins in breast cancer. DNA Repair (Amst) 2020; 93:102922. [PMID: 33087263 DOI: 10.1016/j.dnarep.2020.102922] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Base excision repair (BER) addresses the numerous base lesions and strand breaks induced by exogenous and endogenous stressors daily. The complexity and importance of BER requires careful regulation of basal levels of these proteins and inducible responses following DNA damage. Several reports have noted the dysregulation of BER proteins and defects in BER capacity in cancer. Modulated gene and protein expression of several BER proteins, including APE1, PARP1, POL β, and XRCC1, have been observed in breast cancer. Overexpression of these factors has been associated with chemoresistance and cancer aggressiveness, but the regulatory mechanisms that drive overexpression have not been defined. Here, we review the known transcriptional regulators of these key BER proteins and examine potential mechanisms that may drive overexpression in breast cancer.
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Affiliation(s)
- Griffin Wright
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, AL, USA; Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
| | - Natalie R Gassman
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, AL, USA; Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
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6
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Regulation of limited N-terminal proteolysis of APE1 in tumor via acetylation and its role in cell proliferation. Oncotarget 2017; 7:22590-604. [PMID: 26981776 PMCID: PMC5008384 DOI: 10.18632/oncotarget.8026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 11/25/2022] Open
Abstract
Mammalian apurinic/apyrimidinic (AP) endonuclease 1 (APE1), a ubiquitous and multifunctional protein, plays an essential role in the repair of both endogenous and drug-induced DNA damages in the genome. Unlike its E.coli counterpart Xth, mammalian APE1 has a unique N-terminal domain and possesses both DNA damage repair and transcriptional regulatory functions. Although the overexpression of APE1 in diverse cancer types and the association of APE1 expression with chemotherapy resistance and poor prognosis are well documented, the cellular and molecular mechanisms that alter APE1 functions during tumorigenesis are largely unknown. Here, we show the presence of full-length APE1 and N-terminal truncated isoforms of APE1 in tumor tissue samples of various cancer types. However, primary tumor tissue has higher levels of acetylated APE1 (AcAPE1) as well as full-length APE1 compared to adjacent non-tumor tissue. We found that APE1 is proteolytically cleaved by an unknown serine protease at its N-terminus following residue lysine (Lys) Lys6 and/or Lys7 and after Lys27 and Lys31 or Lys32. Acetylation of these Lys residues in APE1 prevents this proteolysis. The N-terminal domain of APE1 and its acetylation are required for modulation of the expression of hundreds of genes. Importantly, we found that AcAPE1 is essential for sustained cell proliferation. Together, our study demonstrates that increased acetylation levels of APE1 in tumor cells inhibit the limited N-terminal proteolysis of APE1 and thereby maintain the functions of APE1 to promote tumor cells' sustained proliferation and survival.
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7
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Yuan L, Dietrich AK, Ziegler YS, Nardulli AM. 17β-Estradiol alters oxidative damage and oxidative stress response protein expression in the mouse mammary gland. Mol Cell Endocrinol 2016; 426:11-21. [PMID: 26872614 PMCID: PMC4818174 DOI: 10.1016/j.mce.2016.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/27/2016] [Accepted: 02/08/2016] [Indexed: 12/29/2022]
Abstract
Although substantial evidence has demonstrated that parity and 17β-estradiol (E2) reduce mammary carcinogenesis, it is not clear how this protection is conferred. Thus, we examined the effects of parity and E2 treatment in the mammary glands of ovariectomized 15 week-old virgin mice, 15 week-old primiparous mice, and 9 month-old retired breeders. E2 treatment significantly increased lipid peroxidation, protein carbonylation, and protein nitrosylation in the virgin mice, but not in the age-matched primiparous mice or retired breeders. Mammary gland expression of the oxidative stress response protein Cu/Zn superoxide dismutase was consistently reduced in all of the E2-treated mice regardless of parity. Expression of the oxidative stress and DNA repair protein apurinic endonuclease (Ape1) was significantly increased only in the mammary glands of the E2-treated retired breeders. These findings suggest that E2 and parity help to reduce mammary oncogenesis by maintaining the structure and function of proteins, lipids, and DNA.
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Affiliation(s)
- Lisi Yuan
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Alicia K Dietrich
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yvonne S Ziegler
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ann M Nardulli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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8
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Matta J, Morales L, Ortiz C, Adams D, Vargas W, Casbas P, Dutil J, Echenique M, Suárez E. Estrogen Receptor Expression Is Associated with DNA Repair Capacity in Breast Cancer. PLoS One 2016; 11:e0152422. [PMID: 27032101 PMCID: PMC4816515 DOI: 10.1371/journal.pone.0152422] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 03/14/2016] [Indexed: 02/07/2023] Open
Abstract
Estrogen-receptor-positive (ER+) tumors employ complex signaling that engages in crosstalk with multiple pathways through genomic and non-genomic regulation. A greater understanding of these pathways is important for developing improved biomarkers that can better determine treatment choices, risk of recurrence and cancer progression. Deficiencies in DNA repair capacity (DRC) is a hallmark of breast cancer (BC); therefore, in this work we tested whether ER signaling influences DRC. We analyzed the association between ER positivity (% receptor activation) and DRC in 270 BC patients, then further stratified our analysis by HER2 receptor status. Our results show that among HER2 negative, the likelihood of having low DRC values among ER- women is 1.92 (95% CI: 1.03, 3.57) times the likelihood of having low DRC values among ER+ women, even adjusting for different potential confounders (p<0.05); however, a contrary pattern was observed among HER2 positives women. In conclusion, there is an association between DRC levels and ER status, and this association is modified by HER2 receptor status. Adding a DNA repair capacity test to hormone receptor testing may provide new information on defective DNA repair phenotypes, which could better stratify BC patients who have ER+ tumors. ER+/HER2- tumors are heterogeneous, incompletely defined, and clinically challenging to treat; the addition of a DRC test could better characterize and classify these patients as well as help clinicians select optimal therapies, which could improve outcomes and reduce recurrences.
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Affiliation(s)
- Jaime Matta
- Department of Basic Sciences, Division of Pharmacology & Toxicology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
- Department of Basic Sciences, Division of Cancer Biology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
- * E-mail:
| | - Luisa Morales
- Public Health Program, Ponce Health Sciences University, Ponce, Puerto Rico, United States of America
| | - Carmen Ortiz
- Department of Basic Sciences, Division of Pharmacology & Toxicology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
- Department of Basic Sciences, Division of Cancer Biology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
| | - Damian Adams
- Department of Basic Sciences, Division of Pharmacology & Toxicology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
- Department of Basic Sciences, Division of Cancer Biology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
| | - Wanda Vargas
- Department of Basic Sciences, Division of Pharmacology & Toxicology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
- Department of Basic Sciences, Division of Cancer Biology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
| | - Patricia Casbas
- Department of Basic Sciences, Division of Cancer Biology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
- Department of Basic Sciences, Division of Biochemistry, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
| | - Julie Dutil
- Department of Basic Sciences, Division of Cancer Biology, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
- Department of Basic Sciences, Division of Biochemistry, Ponce Health Sciences University-School of Medicine, Ponce Research Institute, Ponce, Puerto Rico, United States of America
| | - Miguel Echenique
- Auxilio Mutuo Hospital, San Juan, Puerto Rico, United States of America
| | - Erick Suárez
- Department of Biostatistics and Epidemiology, Graduate School of Public Health, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico, United States of America
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Dietrich AK, Humphreys GI, Nardulli AM. Expression of estrogen receptor α in the mouse cerebral cortex. Mol Cell Endocrinol 2015; 406:19-26. [PMID: 25700604 PMCID: PMC4773199 DOI: 10.1016/j.mce.2015.02.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 12/15/2022]
Abstract
Although estrogen receptor alpha (ERα) and 17β-estradiol play critical roles in protecting the cerebral cortex from ischemia-induced damage, there has been some controversy about the expression of ERα in this region of the brain. We have examined ERα mRNA and protein levels in the cerebral cortices of female mice at postnatal days 5 and 17 and at 4, 13, and 18 months of age. We found that although ERα transcript levels declined from postnatal day 5 through 18 months of age, ERα protein levels remained stable. Importantly, expression of the E2-regulated progesterone receptor gene was sustained in younger and in older females suggesting that age-related changes in estrogen responsiveness in the cerebral cortex are not due to the absence of ERα protein.
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Affiliation(s)
- Alicia K Dietrich
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Gwendolyn I Humphreys
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Ann M Nardulli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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10
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Thakur S, Dhiman M, Tell G, Mantha AK. A review on protein-protein interaction network of APE1/Ref-1 and its associated biological functions. Cell Biochem Funct 2015; 33:101-12. [DOI: 10.1002/cbf.3100] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 02/10/2015] [Accepted: 02/24/2015] [Indexed: 12/17/2022]
Affiliation(s)
- S. Thakur
- Center for Biosciences, School of Basic and Applied Sciences; Central University of Punjab; Bathinda Punjab India
| | - M. Dhiman
- Center for Genetic Diseases and Molecular Medicine, School of Emerging Life Science Technologies; Central University of Punjab; Bathinda Punjab India
| | - G. Tell
- Department of Medical and Biological Sciences; University of Udine; Udine Italy
| | - A. K. Mantha
- Center for Biosciences, School of Basic and Applied Sciences; Central University of Punjab; Bathinda Punjab India
- Department of Biochemistry and Molecular Biology; University of Texas Medical Branch; Galveston TX USA
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11
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Kaur G, Cholia RP, Mantha AK, Kumar R. DNA repair and redox activities and inhibitors of apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1): a comparative analysis and their scope and limitations toward anticancer drug development. J Med Chem 2014; 57:10241-56. [PMID: 25280182 DOI: 10.1021/jm500865u] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1) is a multifunctional enzyme involved in DNA repair and activation of transcription factors through its redox function. The evolutionarily conserved C- and N-termini are involved in these functions independently. It is also reported that the activity of APE1/Ref-1 abruptly increases several-fold in various human cancers. The control over the outcomes of these two functions is emerging as a new strategy to combine enhanced DNA damage and chemotherapy in order to tackle the major hurdle of increased cancer cell growth and proliferation. Studies have targeted these two domains individually for the design and development of inhibitors for APE1/Ref-1. Here, we have made, for the first time, an attempt at a comparative analysis of APE1/Ref-1 inhibitors that target both DNA repair and redox activities simultaneously. We further discuss their scope and limitations with respect to the development of potential anticancer agents.
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Affiliation(s)
- Gagandeep Kaur
- Laboratory for Drug Design and Synthesis, Centre for Chemical and Pharmaceutical Sciences, School of Basic and Applied Sciences, Central University of Punjab , Bathinda, 151001, Punjab, India
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12
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Li Y, Liu X, Zhou T, Kelley MR, Edwards PA, Gao H, Qiao X. Suppression of choroidal neovascularization through inhibition of APE1/Ref-1 redox activity. Invest Ophthalmol Vis Sci 2014; 55:4461-9. [PMID: 24970265 DOI: 10.1167/iovs.14-14451] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE The redox function of APE1/Ref-1 is a key regulator in pathological angiogenesis, such as retinal neovascularization and tumor growth. In this study, we examined whether inhibition of APE1/Ref-1 redox function by a small molecule inhibitor E3330 suppresses experimental choroidal neovascularization (CNV) in vitro and in vivo. METHODS Primate choroid endothelial cells (CECs) received treatment of 0 to 100 μM E3330 alone or cotreatment of E3330 and 500 μg/mL anti-VEGF antibody bevacizumab. Choroid endothelial cell angiogenic function was examined by cell proliferation, migration, and tube formation assays. The effects of E3330 on NF-κB and STAT3 signaling pathways were determined by reporter gene assay, Western blot, and ELISA. Laser-induced CNV mouse model was used to test the effects of E3330 in vivo. Potential toxicity of E3330 was evaluated by TUNEL assay. RESULTS The E3330 of 25 to 100 μM dose-dependently suppressed CEC proliferation, migration, and tube formation, in the absence of noticeable cell toxicity. Lower doses of E3330 (10-20 μM) reduced the transcriptional activity of NF-κB and STAT3 without affecting protein phosphorylation of both molecules. At the same time, E3330 downregulated MCP-1 production in CECs. The antiangiogenic effect of E3330 was comparable and additive to bevacizumab. The E3330 effectively attenuated the progression of laser-induced CNV in mice after a single intravitreal injection. CONCLUSIONS The APE1/Ref-1 redox function regulates multiple transcription factors and inflammatory molecules, and is essential for CEC angiogenesis. Specific inhibition of APE1/Ref-1 redox function with E3330 may represent a promising novel treatment for wet AMD.
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Affiliation(s)
- Yue Li
- Department of Ophthalmology, Henry Ford Health System, Detroit, Michigan, United States Department of Ophthalmology, Shaanxi Maternity and Child Healthcare Hospital, Xi'an, Shaanxi, People's Republic of China
| | - Xiuli Liu
- Department of Ophthalmology, Henry Ford Health System, Detroit, Michigan, United States
| | - Tongrong Zhou
- Department of Ophthalmology, Henry Ford Health System, Detroit, Michigan, United States
| | - Mark R Kelley
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Paul A Edwards
- Department of Ophthalmology, Henry Ford Health System, Detroit, Michigan, United States
| | - Hua Gao
- Department of Ophthalmology, Henry Ford Health System, Detroit, Michigan, United States
| | - Xiaoxi Qiao
- Department of Ophthalmology, Henry Ford Health System, Detroit, Michigan, United States
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13
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Woo J, Park H, Sung SH, Moon BI, Suh H, Lim W. Prognostic value of human apurinic/apyrimidinic endonuclease 1 (APE1) expression in breast cancer. PLoS One 2014; 9:e99528. [PMID: 24914806 PMCID: PMC4051707 DOI: 10.1371/journal.pone.0099528] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 05/15/2014] [Indexed: 01/10/2023] Open
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) is an essential protein for DNA base excision repair (BER) and redox regulation. The ability of cancer cells to recognize DNA damage and initiate DNA repair is an important mechanism for therapeutic resistance. Several recent studies have suggested that APE1 expression levels and/or subcellular dysregulation may be used to indicate the sensitivity of tumors to radiotherapy or chemotherapy. In this study, we assessed the prognostic significance of APE1 and differences in APE1 expression levels according to breast cancer molecular subtypes. We analyzed formalin-fixed, paraffin-embedded tumor tissue sections from 243 cases diagnosed as invasive breast cancer at Ewha Womans University Medical Center between January 2003 and December 2008. Immunohistochemistry was performed and the nuclear level of APE1 was scored by taking into account the percentage of positive cells. Medical records were reviewed to investigate clinicopathologic characteristics. We found that nuclear APE1 high-level expression (proportion ≥50%) in breast cancer showed a tendency towards unfavorable prognosis regarding disease-free survival (p = 0.093). However, there was no significant difference in overall survival between low and high-level expression groups (p = 0.294). Interestingly, within the Ki-67 low-level expression group, APE1 low-level expression was significantly associated with poor overall survival (p = 0.007). A significant positive correlation was observed between APE1 nuclear expression and estrogen receptor status (75.7% vs. 59.7%, p = 0.022). Also, the luminal A subtype was the most commonly observed breast cancer subtype in the APE1 high-level expression group (61.6% vs. 45.2%, p = 0.000). This study suggests that APE1 expression may be associated with breast cancer prognosis. In particular, its role as a prognostic factor would be significant for breast cancers with a low Ki-67 proliferation index. It is proposed that nuclear APE1 may be a novel target in breast cancer with a low proliferation rate to obtain better outcome.
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Affiliation(s)
- Joohyun Woo
- Department of Surgery, Ewha Womans University School of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea
| | - Heejung Park
- Department of Pathology, Ewha Womans University School of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea
| | - Sun Hee Sung
- Department of Pathology, Ewha Womans University School of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea
| | - Byung-In Moon
- Department of Surgery, Ewha Womans University School of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea
| | - Hyunsuk Suh
- Department of Plastic surgery, Ewha Womans University School of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea
| | - Woosung Lim
- Department of Surgery, Ewha Womans University School of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea
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14
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Caldon CE. Estrogen signaling and the DNA damage response in hormone dependent breast cancers. Front Oncol 2014; 4:106. [PMID: 24860786 PMCID: PMC4030134 DOI: 10.3389/fonc.2014.00106] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 04/28/2014] [Indexed: 12/21/2022] Open
Abstract
Estrogen is necessary for the normal growth and development of breast tissue, but high levels of estrogen are a major risk factor for breast cancer. One mechanism by which estrogen could contribute to breast cancer is via the induction of DNA damage. This perspective discusses the mechanisms by which estrogen alters the DNA damage response (DDR) and DNA repair through the regulation of key effector proteins including ATM, ATR, CHK1, BRCA1, and p53 and the feedback on estrogen receptor signaling from these proteins. We put forward the hypothesis that estrogen receptor signaling converges to suppress effective DNA repair and apoptosis in favor of proliferation. This is important in hormone-dependent breast cancer as it will affect processing of estrogen-induced DNA damage, as well as other genotoxic insults. DDR and DNA repair proteins are frequently mutated or altered in estrogen responsive breast cancer, which will further change the processing of DNA damage. Finally, the action of estrogen signaling on DNA damage is also relevant to the therapeutic setting as the suppression of a DDR by estrogen has the potential to alter the response of cancers to anti-hormone treatment or chemotherapy that induces DNA damage.
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Affiliation(s)
- C Elizabeth Caldon
- Genome and Replication Stability Group, The Kinghorn Cancer Centre, Garvan Institute of Medical Research , Sydney, NSW , Australia ; St Vincent's Clinical School, Faculty of Medicine, UNSW Australia , Sydney, NSW , Australia
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15
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Yuan L, Dietrich AK, Nardulli AM. 17β-Estradiol alters oxidative stress response protein expression and oxidative damage in the uterus. Mol Cell Endocrinol 2014; 382:218-226. [PMID: 24103313 PMCID: PMC3900311 DOI: 10.1016/j.mce.2013.09.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/16/2013] [Accepted: 09/18/2013] [Indexed: 11/19/2022]
Abstract
The steroid hormone 17β-estradiol (E2) has profound effects on the uterus. However, with the E2-induced increase in uterine cell proliferation and metabolism comes increased production of reactive oxygen species (ROS). We examined the expression of an interactive network of oxidative stress response proteins including thioredoxin (Trx), Cu/Zn superoxide dismutase (SOD1), apurinic endonuclease (Ape1), and protein disulfide isomerase (PDI). We demonstrated that treatment of ovariectomized C57BL/6J female mice with E2 increased the mRNA and protein levels of Trx, but decreased SOD1 and Ape1 mRNA and protein expression. In contrast, E2 treatment increased PDI protein levels but had no effect on PDI transcript levels. Interestingly, E2 treatment also increased two markers of cellular damage, lipid peroxidation and protein carbonylation. Our studies suggest that the decreased expression of SOD1 and Ape1 caused by E2 treatment may in the long term result in disruption of ROS regulation and play a role in endometrial carcinogenesis.
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Affiliation(s)
- Lisi Yuan
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Alicia K Dietrich
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Ann M Nardulli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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16
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Carter EL, Ragsdale SW. Modulation of nuclear receptor function by cellular redox poise. J Inorg Biochem 2014; 133:92-103. [PMID: 24495544 DOI: 10.1016/j.jinorgbio.2014.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/28/2013] [Accepted: 01/09/2014] [Indexed: 02/09/2023]
Abstract
Nuclear receptors (NRs) are ligand-responsive transcription factors involved in diverse cellular processes ranging from metabolism to circadian rhythms. This review focuses on NRs that contain redox-active thiol groups, a common feature within the superfamily. We will begin by describing NRs, how they regulate various cellular processes and how binding ligands, corepressors and/or coactivators modulate their activity. We will then describe the general area of redox regulation, especially as it pertains to thiol-disulfide interconversion and the cellular systems that respond to and govern this redox equilibrium. Lastly, we will discuss specific examples of NRs whose activities are regulated by redox-active thiols. Glucocorticoid, estrogen, and the heme-responsive receptor, Rev-erb, will be described in the most detail as they exhibit archetypal redox regulatory mechanisms.
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Affiliation(s)
- Eric L Carter
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Stephen W Ragsdale
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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17
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Abdel-Fatah TMA, Perry C, Moseley P, Johnson K, Arora A, Chan S, Ellis IO, Madhusudan S. Clinicopathological significance of human apurinic/apyrimidinic endonuclease 1 (APE1) expression in oestrogen-receptor-positive breast cancer. Breast Cancer Res Treat 2014; 143:411-21. [PMID: 24381055 DOI: 10.1007/s10549-013-2820-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 01/28/2023]
Abstract
Oestrogen metabolites can induce oxidative DNA base damage and generate potentially mutagenic apurinic sites (AP sites) in the genomic DNA. If unrepaired, mutagenic AP sites could drive breast cancer pathogenesis and aggressive phenotypes. Human apurinic/apyrimidinic endonuclease 1 (APE1) is a key DNA base excision repair (BER) protein and essential for processing AP sites generated either directly by oestrogen metabolites or during BER of oxidative base damage. Our hypothesis is that altered APE1 expression may be associated with aggressive tumour biology and impact upon clinical outcomes in breast cancer. In the current study, we have investigated APE1 protein expression in a large cohort of breast cancers (n = 1285) and correlated to clinicopathological features and survival outcomes. Low APE1 protein expression was associated with high histological grade (p < 0.000001), high mitotic index (p < 0.000001), glandular de-differentiation (p < 0.000001), pleomorphism (p = 0.003), absence of hormonal receptors (ER-/PgR-/AR-) (p < 0.0001) and presence of triple negative phenotype (p = 0.001). Low APE1 protein expression was associated with loss of BRCA1, low XRCC1, low FEN1, low SMUG1 and low pol β (ps < 0.0001). High MIB1 (p = 0.048), bcl-2 negativity (p < 0.0001) and low TOP2A (p < 0.0001) were likely in low APE1 tumours. In the ER-positive sub-group, specifically, low APE1 remains significantly associated with high histological grade, high mitotic index, glandular de-differentiation (ps < 0.00001) and poor breast cancer specific survival (p = 0.007). In the ER-positive cohort that received adjuvant endocrine therapy, low APE1 protein expression is associated with poor survival (p = 0.006). In multivariate analysis, low APE1 remains independently associated with poor survival in ER-positive tumours (p = 0.048). We conclude that low APE1 expression may have prognostic and predictive significance in ER-positive breast cancers.
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18
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Hashimoto S, Imaoka S. Protein-disulfide isomerase regulates the thyroid hormone receptor-mediated gene expression via redox factor-1 through thiol reduction-oxidation. J Biol Chem 2012; 288:1706-16. [PMID: 23148211 DOI: 10.1074/jbc.m112.365239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Protein-disulfide isomerase (PDI) is a dithiol/disulfide oxidoreductase that regulates the redox state of proteins. We previously found that overexpression of PDI in rat pituitary tumor (GH3) cells suppresses 3,3',5-triiodothyronine (T(3))-stimulated growth hormone (GH) expression, suggesting the contribution of PDI to the T(3)-mediated gene expression via thyroid hormone receptor (TR). In the present study, we have clarified the mechanism of regulation by which TR function is regulated by PDI. Overexpression of wild-type but not redox-inactive mutant PDI suppressed the T(3)-induced GH expression, suggesting that the redox activity of PDI contributes to the suppression of GH. We considered that PDI regulates the redox state of the TR and focused on redox factor-1 (Ref-1) as a mediator of the redox regulation of TR by PDI. Interaction between Ref-1 and TRβ1 was detected. Overexpression of wild-type but not C64S Ref-1 facilitated the GH expression, suggesting that redox activity of Cys-64 in Ref-1 is involved in the TR-mediated gene expression. Moreover, PDI interacted with Ref-1 and changed the redox state of Ref-1, suggesting that PDI controls the redox state of Ref-1. Our studies suggested that Ref-1 contributes to TR-mediated gene expression and that the redox state of Ref-1 is regulated by PDI. Redox regulation of PDI via Ref-1 is a new aspect of PDI function.
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Affiliation(s)
- Shoko Hashimoto
- Research Center for Environmental Bioscience and Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Hyogo, Sanda 669-1337, Japan
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19
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Artacho-Cordón A, Artacho-Cordón F, Ríos-Arrabal S, Calvente I, Núñez MI. Tumor microenvironment and breast cancer progression: a complex scenario. Cancer Biol Ther 2012; 13:14-24. [PMID: 22336584 DOI: 10.4161/cbt.13.1.18869] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It is now widely accepted that the development and progression of a tumor toward the malignant phenotype is highly dependent on interactions between tumor cells and the tumor microenvironment. Different components of the tumor microenvironment may have stimulatory or inhibitory effects on tumor progression by regulating the gene expression repertoire in tumor cells and stromal cells. This review analyzes novel research findings on breast cancer progression, discussing acquisition of the metastatic phenotype in breast disease in relation to different aspects of cross-talk among components of the tumor microenvironment. Knowledge of the interaction of all of these factors would contribute to elucidating the mechanisms that disrupt regulatory/signaling cascades and downstream effects in breast cancer.
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20
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Kelley MR, Georgiadis MM, Fishel ML. APE1/Ref-1 role in redox signaling: translational applications of targeting the redox function of the DNA repair/redox protein APE1/Ref-1. Curr Mol Pharmacol 2012; 5:36-53. [PMID: 22122463 DOI: 10.2174/1874467211205010036] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 08/18/2010] [Accepted: 08/25/2010] [Indexed: 12/22/2022]
Abstract
The heterogeneity of most cancers diminishes the treatment effectiveness of many cancer-killing regimens. Thus, treatments that hold the most promise are ones that block multiple signaling pathways essential to cancer survival. One of the most promising proteins in that regard is APE1, whose reduction-oxidation activity influences multiple cancer survival mechanisms, including growth, proliferation, metastasis, angiogenesis, and stress responses. With the continued research using APE1 redox specific inhibitors alone or coupled with developing APE1 DNA repair inhibitors it will now be possible to further delineate the role of APE1 redox, repair and protein-protein interactions. Previously, use of siRNA or over expression approaches, while valuable, do not give a clear picture of the two major functions of APE1 since both techniques severely alter the cellular milieu. Additionally, use of the redox-specific APE1 inhibitor, APX3330, now makes it possible to study how inhibition of APE1's redox signaling can affect multiple tumor pathways and can potentiate the effectiveness of existing cancer regimens. Because APE1 is an upstream effector of VEGF, as well as other molecules that relate to angiogenesis and the tumor microenvironment, it is also being studied as a possible treatment for agerelated macular degeneration and diabetic retinopathy. This paper reviews all of APE1's functions, while heavily focusing on its redox activities. It also discusses APE1's altered expression in many cancers and the therapeutic potential of selective inhibition of redox regulation, which is the subject of intense preclinical studies.
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Affiliation(s)
- Mark R Kelley
- Department of Pediatrics (Section of Hematology/Oncology), Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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21
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Acetylation on critical lysine residues of Apurinic/apyrimidinic endonuclease 1 (APE1) in triple negative breast cancers. Biochem Biophys Res Commun 2012; 424:34-9. [PMID: 22713458 DOI: 10.1016/j.bbrc.2012.06.039] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Accepted: 06/09/2012] [Indexed: 12/18/2022]
Abstract
Protein acetylation plays many roles within living cells, modulating metabolism, signaling and cell response to environmental stimuli, as well as having an impact on pathological conditions, such as cancer pathogenesis and progression. The Apurinic/apyrimidinic endonuclease APE1 is a vital protein that exerts many functions in mammalian cells, acting as a pivotal enzyme in the base excision repair (BER) pathway of DNA lesions, as transcriptional modulator and being also involved in RNA metabolism. As an eclectic and abundant protein, APE1 is extensively modulated through post-translational modifications, including acetylation. Many findings have linked APE1 to cancer development and onset of chemo- and radio-resistance. Here, we focus on APE1 acetylation pattern in triple negative breast cancer (TNBC). We describe the validation and characterization of a polyclonal antibody that is specific for the acetylation on lysine 35 of the protein. Finally, we use the new antibody to analyze the APE1 acetylation pattern on a cohort of TNBC specimens, exploiting immunohistochemistry. Our findings reveal a profound deregulation of APE1 acetylation status in TNBC, opening new perspectives for future improvements on treatment and prognosis of this molecular subtype of breast carcinomas.
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22
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Schultz-Norton JR, Ziegler YS, Nardulli AM. ERα-associated protein networks. Trends Endocrinol Metab 2011; 22:124-9. [PMID: 21371903 DOI: 10.1016/j.tem.2010.11.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Revised: 11/30/2010] [Accepted: 11/30/2010] [Indexed: 11/21/2022]
Abstract
Estrogen receptor α (ERα) is a ligand-activated transcription factor that, upon binding hormone, interacts with specific recognition sequences in DNA. An extensive body of literature has documented the association of individual regulatory proteins with ERα. It has recently become apparent that, instead of simply recruiting individual proteins, ERα recruits interconnected networks of proteins with discrete activities that play crucial roles in maintaining the structure and function of the receptor, stabilizing the receptor-DNA interaction, influencing estrogen-responsive gene expression, and repairing misfolded proteins and damaged DNA. Together these studies suggest that the DNA-bound ERα serves as a nucleating factor for the recruitment of protein complexes involved in key processes including the oxidative stress response, DNA repair, and transcription regulation.
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Affiliation(s)
- Jennifer R Schultz-Norton
- Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 407 South Goodwin Avenue, Urbana, IL 61801, USA
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23
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Jedinak A, Dudhgaonkar S, Kelley MR, Sliva D. Apurinic/Apyrimidinic endonuclease 1 regulates inflammatory response in macrophages. Anticancer Res 2011; 31:379-385. [PMID: 21378315 PMCID: PMC3256557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The multi-functional apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) DNA repair and redox signaling protein has been shown to have a role in cancer growth and survival, however, little has been investigated concerning its role in inflammation. In this study, an APE1 redox-specific inhibitor (E3330) was used in lypopolysaccharide (LPS)-stimulated macrophages (RAW264.7). E3330 clearly suppressed secretion of inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin (IL-6) and IL-12 and inflammatory mediators nitric oxide (NO) as well as prostaglandin E(2) (PGE(2)) from the LPS-stimulated RAW264.7 cells. These data were supported by the down-regulation of the LPS-dependent expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) genes in the RAW264.7 cells. The effects of E3330 were mediated by the inhibition of transcription factors nuclear factor-κB (NF-κB) and activator protein 1 (AP-1) in the LPS-stimulated macrophages, both known targets of APE1. In conclusion, pharmacological inhibition of APE1 by E3330 suppresses inflammatory response in activated macrophages and can be considered as a novel therapeutic strategy for the inhibition of tumor-associated macrophages.
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Affiliation(s)
- Andrej Jedinak
- Cancer Research Laboratory, Methodist Research Institute, Indiana University Health, 1800 N Capitol Ave, E504, Indianapolis, IN 46202, USA
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24
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Tell G, Fantini D, Quadrifoglio F. Understanding different functions of mammalian AP endonuclease (APE1) as a promising tool for cancer treatment. Cell Mol Life Sci 2010; 67:3589-608. [PMID: 20706766 PMCID: PMC11115856 DOI: 10.1007/s00018-010-0486-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 12/27/2022]
Abstract
The apurinic endonuclease 1/redox factor-1 (APE1) has a crucial function in DNA repair and in redox signaling in mammals, and recent studies identify it as an excellent target for sensitizing tumor cells to chemotherapy. APE1 is an essential enzyme in the base excision repair pathway of DNA lesions caused by oxidation and alkylation. As importantly, APE1 also functions as a redox agent maintaining transcription factors involved in cancer promotion and progression in an active reduced state. Very recently, a new unsuspected function of APE1 in RNA metabolism was discovered, opening new perspectives for this multifunctional protein. These observations underline the necessity to understand the molecular mechanisms responsible for fine-tuning its different biological functions. This survey intends to give an overview of the multifunctional roles of APE1 and their regulation in the context of considering this protein a promising tool for anticancer therapy.
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Affiliation(s)
- Gianluca Tell
- Department of Biomedical Sciences and Technologies, University of Udine, Piazzale Kolbe 4, 33100, Udine, Italy.
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25
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Human AP endonuclease (APE1/Ref-1) and its acetylation regulate YB-1-p300 recruitment and RNA polymerase II loading in the drug-induced activation of multidrug resistance gene MDR1. Oncogene 2010; 30:482-93. [PMID: 20856196 PMCID: PMC3010319 DOI: 10.1038/onc.2010.435] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Overexpression of human AP-endonuclease (APE1/Ref-1), a key enzyme in the DNA base excision repair (BER) pathway, is often associated with tumor cell resistance to various anticancer drugs. In this study, we examined the molecular basis of transcriptional regulatory (non repair) function of APE1 in promoting resistance to certain types of drugs. We have recently shown that APE1 stably interacts with Y-box-binding protein 1 (YB-1), and acts as its coactivator for the expression of multidrug resistance gene MDR1, thereby causing drug-resistance. Here we show for the first time that APE1 is stably associated with the basic transcription factor RNA polymerase II (RNA pol II) and the coactivator p300 on the endogenous MDR1 promoter. APE1’s depletion significantly reduces YB-1/p300 recruitment to the promoter, resulting in reduced RNA pol II loading. Drug-induced APE1 acetylation which is mediated by p300 enhances formation of acetylated APE1 (AcAPE1)/YB-1/p300 complex on the MDR1 promoter. Enhanced recruitment of this complex increases MDR1 promoter dependent luciferase activity and its endogenous expression. Using APE1 downregulated cells and cells overexpressing wild type APE1 or its nonacetylable mutant we have demonstrated that the loss of APE1’s acetylation impaired MDR1 activation and sensitizes the cells to cisplatin or etoposide. We have thus established the basis for APE1’s acetylation-dependent regulatory function in inducing MDR1-mediated drug resistance.
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26
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Curtis CD, Thorngren DL, Nardulli AM. Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues. BMC Cancer 2010; 10:9. [PMID: 20064251 PMCID: PMC2830938 DOI: 10.1186/1471-2407-10-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 01/11/2010] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND During the course of normal cellular metabolism, oxygen is consumed and reactive oxygen species (ROS) are produced. If not effectively dissipated, ROS can accumulate and damage resident proteins, lipids, and DNA. Enzymes involved in redox regulation and DNA repair dissipate ROS and repair the resulting damage in order to preserve a functional cellular environment. Because increased ROS accumulation and/or unrepaired DNA damage can lead to initiation and progression of cancer and we had identified a number of oxidative stress and DNA repair proteins that influence estrogen responsiveness of MCF-7 breast cancer cells, it seemed possible that these proteins might be differentially expressed in normal mammary tissue, benign hyperplasia (BH), ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC). METHODS Immunohistochemistry was used to examine the expression of a number of oxidative stress proteins, DNA repair proteins, and damage markers in 60 human mammary tissues which were classified as BH, DCIS or IBC. The relative mean intensity was determined for each tissue section and ANOVA was used to detect statistical differences in the relative expression of BH, DCIS and IBC compared to normal mammary tissue. RESULTS We found that a number of these proteins were overexpressed and that the cellular localization was altered in human breast cancer tissue. CONCLUSIONS Our studies suggest that oxidative stress and DNA repair proteins not only protect normal cells from the damaging effects of ROS, but may also promote survival of mammary tumor cells.
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Affiliation(s)
- Carol D Curtis
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana IL 61801, USA
| | - Daniel L Thorngren
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana IL 61801, USA
| | - Ann M Nardulli
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana IL 61801, USA
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27
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Rao AK, Ziegler YS, McLeod IX, Yates JR, Nardulli AM. Thioredoxin and thioredoxin reductase influence estrogen receptor alpha-mediated gene expression in human breast cancer cells. J Mol Endocrinol 2009; 43:251-61. [PMID: 19620238 PMCID: PMC2994277 DOI: 10.1677/jme-09-0053] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Accumulation of reactive oxygen species (ROS) in cells damages resident proteins, lipids, and DNA. In order to overcome the oxidative stress that occurs with ROS accumulation, cells must balance free radical production with an increase in the level of antioxidant enzymes that convert free radicals to less harmful species. We identified two antioxidant enzymes, thioredoxin (Trx) and Trx reductase (TrxR), in a complex associated with the DNA-bound estrogen receptor alpha (ERalpha). Western analysis and immunocytochemistry were used to demonstrate that Trx and TrxR are expressed in the cytoplasm and in the nuclei of MCF-7 human breast cancer cells. More importantly, endogenously expressed ERalpha, Trx, and TrxR interact and ERalpha and TrxR associate with the native, estrogen-responsive pS2 and progesterone receptor genes in MCF-7 cells. RNA interference assays demonstrated that Trx and TrxR differentially influence estrogen-responsive gene expression and that together, 17beta-estradiol, Trx, and TrxR alter hydrogen peroxide (H(2)O(2)) levels in MCF-7 cells. Our findings suggest that Trx and TrxR are multifunctional proteins that, in addition to modulating H(2)O(2) levels and transcription factor activity, aid ERalpha in regulating the expression of estrogen-responsive genes in target cells.
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Affiliation(s)
- Abhi K Rao
- Department of Cellular and Developmental Biology, University of Illinois at Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, Illinois 61801, USA
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28
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Abstract
Regulating gene expression is a complex process requiring the interaction of multiple transcription factors with their cognate recognition sequences. While these DNA-bound transcription factors are the primary drivers of gene expression, the capacity of a transcription factor to alter gene expression is tempered by its association with a host of coregulatory proteins that are recruited to the DNA-bound transcription factor. We have developed a novel approach to isolate large complexes of proteins associated with the DNA-bound estrogen receptor alpha (ERalpha) using an agarose-based electrophoretic mobility shift assay (EMSA). This method should be readily adapted to a variety of cultured cell lines, DNA sequences, and transcription factors and has the potential to provide valuable information about a wide variety of regulatory proteins involved in influencing gene expression.
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