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Atri Y, Bharti H, Sahani N, Sarkar DP, Nag A. CUL4A silencing attenuates cervical carcinogenesis and improves Cisplatin sensitivity. Mol Cell Biochem 2024; 479:1041-1058. [PMID: 37285039 DOI: 10.1007/s11010-023-04776-2] [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: 07/28/2022] [Accepted: 05/21/2023] [Indexed: 06/08/2023]
Abstract
CUL4A is an ubiquitin ligase deregulated in numerous pathologies including cancer and even hijacked by viruses for facilitating their survival and propagation. However, its role in Human papilloma virus (HPV)-mediated cervical carcinogenesis remains elusive. The UALCAN and GEPIA datasets were analyzed to ascertain the transcript levels of CUL4A in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) patients. Subsequently, various biochemical assays were employed to explore the functional contribution of CUL4A in cervical carcinogenesis and to shed some light on its involvement in Cisplatin resistance in cervical cancer. Our UALCAN and GEPIA datasets analyses reveal elevated CUL4A transcript levels in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) patients that correlate with adverse clinicopathological parameters such as tumor stage and lymph node metastasis. Kaplan-Meier plot and GEPIA assessment depict poor prognosis of CESC patients having high CUL4A expression. Varied biochemical assays illustrate that CUL4A inhibition severely curtails hallmark malignant properties such as cellular proliferation, migration, and invasion of cervical cancer cells. We also show that CUL4A knockdown in HeLa cells causes increased susceptibility and better apoptotic induction toward Cisplatin, a mainstay drug used in cervical cancer treatment. More interestingly, we find reversion of Cisplatin-resistant phenotype of HeLa cells and an augmented cytotoxicity towards the platinum compound upon CUL4A downregulation. Taken together, our study underscores CUL4A as a cervical cancer oncogene and illustrates its potential as a prognosis indicator. Our investigation provides a novel avenue in improving current anti-cervical cancer therapy and overcoming the bottle-neck of Cisplatin resistance.
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Affiliation(s)
- Yama Atri
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Hina Bharti
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Nandini Sahani
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Debi P Sarkar
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Alo Nag
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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2
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Porto E, Loula P, Strand S, Hankeln T. Molecular analysis of the human cytoglobin mRNA isoforms. J Inorg Biochem 2024; 251:112422. [PMID: 38016326 DOI: 10.1016/j.jinorgbio.2023.112422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/26/2023] [Accepted: 10/29/2023] [Indexed: 11/30/2023]
Abstract
Multiple functions have been proposed for the ubiquitously expressed vertebrate globin cytoglobin (Cygb), including nitric oxide (NO) metabolism, lipid peroxidation/signalling, superoxide dismutase activity, reactive oxygen/nitrogen species (RONS) scavenging, regulation of blood pressure, antifibrosis, and both tumour suppressor and oncogenic effects. Since alternative splicing can expand the biological roles of a gene, we investigated whether this mechanism contributes to the functional diversity of Cygb. By mining of cDNA data and molecular analysis, we identified five alternative mRNA isoforms for the human CYGB gene (V-1 to V-5). Comprehensive RNA-seq analyses of public datasets from human tissues and cells confirmed that the canonical CYGB V-1 isoform is the primary CYGB transcript in the majority of analysed datasets. Interestingly, we revealed that isoform V-3 represented the predominant CYGB variant in hepatoblastoma (HB) cell lines and in the majority of analysed normal and HB liver tissues. CYGB V-3 mRNA is transcribed from an alternate upstream promoter and hypothetically encodes a N-terminally truncated CYGB protein, which is not recognized by some antibodies used in published studies. Little to no transcriptional evidence was found for the other CYGB isoforms. Comparative transcriptomics and flow cytometry on CYGB+/+ and gene-edited CYGB-/- HepG2 HB cells did not unveil a knockout phenotype and, thus, a potential function for CYGB V-3. Our study reveals that the CYGB gene is transcriptionally more complex than previously described as it expresses alternative mRNA isoforms of unknown function. Additional experimental data are needed to clarify the biological meaning of those alternative CYGB transcripts.
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Affiliation(s)
- Elena Porto
- Institute of Organismic and Molecular Evolution, Molecular Genetics & Genome Analysis Group, Johannes Gutenberg University Mainz, J. J. Becher-Weg 30A, D-55128 Mainz, Germany
| | - Paraskevi Loula
- Institute of Organismic and Molecular Evolution, Molecular Genetics & Genome Analysis Group, Johannes Gutenberg University Mainz, J. J. Becher-Weg 30A, D-55128 Mainz, Germany
| | - Susanne Strand
- Department of Internal Medicine I, Molecular Hepatology, University Medical Center, Johannes Gutenberg University Mainz, Obere Zahlbacher Strasse 63, 55131 Mainz, Germany
| | - Thomas Hankeln
- Institute of Organismic and Molecular Evolution, Molecular Genetics & Genome Analysis Group, Johannes Gutenberg University Mainz, J. J. Becher-Weg 30A, D-55128 Mainz, Germany.
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Reeder BJ. Insights into the function of cytoglobin. Biochem Soc Trans 2023; 51:1907-1919. [PMID: 37721133 PMCID: PMC10657185 DOI: 10.1042/bst20230081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/19/2023]
Abstract
Since its discovery in 2001, the function of cytoglobin has remained elusive. Through extensive in vitro and in vivo research, a range of potential physiological and pathological mechanisms has emerged for this multifunctional member of the hemoglobin family. Currently, over 200 research publications have examined different aspects of cytoglobin structure, redox chemistry and potential roles in cell signalling pathways. This research is wide ranging, but common themes have emerged throughout the research. This review examines the current structural, biochemical and in vivo knowledge of cytoglobin published over the past two decades. Radical scavenging, nitric oxide homeostasis, lipid binding and oxidation and the role of an intramolecular disulfide bond on the redox chemistry are examined, together with aspects and roles for Cygb in cancer progression and liver fibrosis.
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Affiliation(s)
- Brandon J Reeder
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, U.K
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Jaiswal N, Nandi D, Cheema PS, Nag A. The anaphase-promoting complex/cyclosome co-activator, Cdh1, is a novel target of human papillomavirus 16 E7 oncoprotein in cervical oncogenesis. Carcinogenesis 2022; 43:988-1001. [PMID: 35738876 DOI: 10.1093/carcin/bgac057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/01/2022] [Accepted: 06/23/2022] [Indexed: 01/13/2023] Open
Abstract
The transforming properties of the high-risk human papillomavirus (HPV) E7 oncoprotein are indispensable for driving the virus life cycle and pathogenesis. Besides inactivation of the retinoblastoma family of tumor suppressors as part of its oncogenic endeavors, E7-mediated perturbations of eminent cell cycle regulators, checkpoint proteins and proto-oncogenes are considered to be the tricks of its transformative traits. However, many such critical interactions are still unknown. In the present study, we have identified the anaphase-promoting complex/cyclosome (APC) co-activator, Cdh1, as a novel interacting partner and a degradation target of E7. We found that HPV16 E7-induced inactivation of Cdh1 promoted abnormal accumulation of multiple Cdh1 substrates. Such a mode of deregulation possibly contributes to HPV-mediated cervical oncogenesis. Our mapping studies recognized the C-terminal zinc-finger motif of E7 to associate with Cdh1 and interfere with the timely degradation of FoxM1, a bona fide Cdh1 substrate and a potent oncogene. Importantly, the E7 mutant with impaired interaction with Cdh1 exhibited defects in its ability for overriding typical cell cycle transition and oncogenic transformation, thereby validating the functional and pathological significance of the E7-Cdh1 axis during cervical carcinoma progression. Altogether, the findings from our study discover a unique nexus between E7 and APC/C-Cdh1, thereby adding to our understanding of the mechanism of E7-induced carcinogenesis and provide a promising target for the management of cervical carcinoma.
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Affiliation(s)
- Neha Jaiswal
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
| | - Deeptashree Nandi
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
| | - Pradeep Singh Cheema
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
| | - Alo Nag
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
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DeMartino AW, Amdahl MB, Bocian K, Rose JJ, Tejero J, Gladwin MT. Redox sensor properties of human cytoglobin allosterically regulate heme pocket reactivity. Free Radic Biol Med 2021; 162:423-434. [PMID: 33144263 PMCID: PMC7889637 DOI: 10.1016/j.freeradbiomed.2020.10.321] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/21/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022]
Abstract
Cytoglobin is a conserved hemoprotein ubiquitously expressed in mammalian tissues, which conducts electron transfer reactions with proposed signaling functions in nitric oxide (NO) and lipid metabolism. Cytoglobin has an E7 distal histidine (His81), which unlike related globins such as myoglobin and hemoglobin, is in equilibrium between a bound, hexacoordinate state and an unbound, pentacoordinate state. The His81 binding equilibrium appears to be allosterically modulated by the presence of an intramolecular disulfide between two cysteines (Cys38 and Cys83). The formation of this disulfide bridge regulates nitrite reductase activity and lipid binding. Herein, we attempt to clarify the effects of defined thiol oxidation states on small molecule binding of cytoglobin heme, using cyanide binding to probe the ferric state. Cyanide binding kinetics to wild-type cytoglobin reveal at least two kinetically distinct subpopulations, depending on thiol oxidation states. Experiments with covalent thiol modification by NEM, glutathione, and amino acid substitutions (C38S, C83S and H81A), indicate that subpopulations ranging from fully reduced thiols, single thiol oxidation, and intramolecular disulfide formation determine heme binding properties by modulating the histidine-heme affinity and ligand binding. The redox modulation of ligand binding is sensitive to physiological levels of hydrogen peroxide, with a functional midpoint redox potential for the native cytoglobin intramolecular disulfide bond of -189 ± 4 mV, a value within the boundaries of intracellular redox potentials. These results support the hypothesis that Cys38 and Cys83 on cytoglobin serve as sensitive redox sensors that modulate the cytoglobin distal heme pocket reactivity and ligand binding.
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Affiliation(s)
- Anthony W DeMartino
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthew B Amdahl
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kaitlin Bocian
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jason J Rose
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, United States; Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, United States
| | - Jesús Tejero
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, United States; Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, United States; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15261, United States.
| | - Mark T Gladwin
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, United States; Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, United States.
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Cai Z, Moten A, Peng D, Hsu CC, Pan BS, Manne R, Li HY, Lin HK. The Skp2 Pathway: A Critical Target for Cancer Therapy. Semin Cancer Biol 2020; 67:16-33. [PMID: 32014608 DOI: 10.1016/j.semcancer.2020.01.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/22/2020] [Accepted: 01/25/2020] [Indexed: 12/16/2022]
Abstract
Strictly regulated protein degradation by ubiquitin-proteasome system (UPS) is essential for various cellular processes whose dysregulation is linked to serious diseases including cancer. Skp2, a well characterized component of Skp2-SCF E3 ligase complex, is able to conjugate both K48-linked ubiquitin chains and K63-linked ubiquitin chains on its diverse substrates, inducing proteasome mediated proteolysis or modulating the function of tagged substrates respectively. Overexpression of Skp2 is observed in various human cancers associated with poor survival and adverse therapeutic outcomes, which in turn suggests that Skp2 engages in tumorigenic activity. To that end, the oncogenic properties of Skp2 are demonstrated by various genetic mouse models, highlighting the potential of Skp2 as a target for tackling cancer. In this article, we will describe the downstream substrates of Skp2 as well as upstream regulators for Skp2-SCF complex activity. We will further summarize the comprehensive oncogenic functions of Skp2 while describing diverse strategies and therapeutic platforms currently available for developing Skp2 inhibitors.
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Affiliation(s)
- Zhen Cai
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA.
| | - Asad Moten
- National Capital Consortium, Department of Defense, Washington DC, 20307, USA; Institute for Complex Systems, HealthNovations International, Houston, TX, 77089, USA; Center for Cancer Research, National Institutes of Health, Bethesda, MD, 20814, USA; Center on Genomics, Vulnerable Populations, and Health Disparities, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Danni Peng
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Che-Chia Hsu
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Bo-Syong Pan
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Rajeshkumar Manne
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Hong-Yu Li
- University of Arkansas for Medical Sciences, College of Pharmacy, Division of Pharmaceutical Science, 200 South Cedar, Little Rock AR 72202, USA
| | - Hui-Kuan Lin
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA; Graduate Institute of Basic Medical Science, China Medical University, Taichung 404, Taiwan; Department of Biotechnology, Asia University, Taichung 41354, Taiwan.
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7
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Du S, Wang S, Zhang F, Lv Y. SKP2, positively regulated by circ_ODC1/miR‐422a axis, promotes the proliferation of retinoblastoma. J Cell Biochem 2019; 121:322-331. [PMID: 31297892 DOI: 10.1002/jcb.29177] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Shanshan Du
- Department of Ophthalmology The First Affiliated Hospital of Zhengzhou University Zhengzhou Henan China
| | - Shuai Wang
- Department of Ophthalmology The First Affiliated Hospital of Zhengzhou University Zhengzhou Henan China
| | - Fengyan Zhang
- Department of Ophthalmology The First Affiliated Hospital of Zhengzhou University Zhengzhou Henan China
| | - Yong Lv
- Department of Ophthalmology The First Affiliated Hospital of Zhengzhou University Zhengzhou Henan China
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