1
|
Long Y, Hu Z, Yang D, Wang F, Zhao C, Zhang Y, Zhang Y, Ma H, Lv H. Pharmacological inhibition of the ubiquitin-specific protease 8 effectively suppresses glioblastoma cell growth. Open Life Sci 2023; 18:20220562. [PMID: 36816802 PMCID: PMC9922063 DOI: 10.1515/biol-2022-0562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/08/2022] [Accepted: 01/04/2023] [Indexed: 02/11/2023] Open
Abstract
Glioblastoma (GBM) is a malignant brain tumor. The purpose of this study is to estimate the potential effects and underlying mechanisms of a ubiquitin-specific protease 8 (USP8) small-molecule inhibitor on the phenotypic characteristics of GBM cells. The growth, migration, invasion, and stemness of GBM LN229 and T98G cells were evaluated by conducting cell proliferation, colony formation, wound healing, transwell, Ki-67 staining, spheroid formation, and ionizing radiation assays, and the results collectively showed the suppressive effects of USP8 inhibition on GBM cells. Furthermore, transcriptomic profiling of GBM cells treated with the USP8 inhibitor deubiquitinase (DUB)-IN-1 revealed significantly altered mRNA expression induced by pharmacological USP8 inhibition, from which we confirmed downregulated Aurora kinase A (AURKA) protein levels using immunoblotting assays. Our findings indicated that the proliferation, invasion, and stemness of LN229 and T98G cells were markedly suppressed by USP8 inhibition. Pharmacological USP8 suppression elicits multiple tumor-inhibitory effects, likely through dysregulating various mRNA expression events, including that of the key cell cycle regulator and oncogenic protein AURKA. Therefore, our observations corroborate the GBM-supportive roles of USP8 and suggest pharmacological USP8 inhibition is a viable therapeutic approach to target GBM. The purpose of this study was to investigate the effect and mechanism of action of the USP8 inhibitor DUB-IN-1 on GBM.
Collapse
Affiliation(s)
- Yu Long
- Department of Pharmacy, The Second Affiliated Hospital, Dalian Medical University, No. 467 Zhongshan Road, Dalian 116000, China
| | - Zengchun Hu
- Department of Neurosurgery, The Second Affiliated Hospital, Dalian Medical University, Dalian 116000, China
| | - Dian Yang
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian 116000, China
| | - Fuqiang Wang
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian 116000, China
| | - Chen’ge Zhao
- Department of Pharmacy, The Second Affiliated Hospital, Dalian Medical University, No. 467 Zhongshan Road, Dalian 116000, China
| | - Yang Zhang
- Department of Pharmacy, The Second Affiliated Hospital, Dalian Medical University, No. 467 Zhongshan Road, Dalian 116000, China
| | - Yingqiu Zhang
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian 116000, China
| | - Hui Ma
- Department of Pharmacy, The Second Affiliated Hospital, Dalian Medical University, No. 467 Zhongshan Road, Dalian 116000, China
| | - Huiyi Lv
- Department of Pharmacy, The Second Affiliated Hospital, Dalian Medical University, No. 467 Zhongshan Road, Dalian 116000, China,Dalian Kexiang Technology Development Co., LTD, No. 467 Zhongshan Road, Dalian 116000, China
| |
Collapse
|
2
|
Degl’Innocenti E, Poloni TE, Medici V, Recupero L, Dell’Amico C, Vannini E, Borello U, Mazzanti CM, Onorati M, Dell’Anno MT. Centrin 2: A Novel Marker of Mature and Neoplastic Human Astrocytes. Front Cell Neurosci 2022; 16:858347. [PMID: 35573835 PMCID: PMC9100563 DOI: 10.3389/fncel.2022.858347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
As microtubule-organizing centers (MTOCs), centrosomes play a pivotal role in cell division, neurodevelopment and neuronal maturation. Among centrosomal proteins, centrin-2 (CETN2) also contributes to DNA repair mechanisms which are fundamental to prevent genomic instability during neural stem cell pool expansion. Nevertheless, the expression profile of CETN2 in human neural stem cells and their progeny is currently unknown. To address this question, we interrogated a platform of human neuroepithelial stem (NES) cells derived from post mortem developing brain or established from pluripotent cells and demonstrated that while CETN2 retains its centrosomal location in proliferating NES cells, its expression pattern changes upon differentiation. In particular, we found that CETN2 is selectively expressed in mature astrocytes with a broad cytoplasmic distribution. We then extended our findings on human autoptic nervous tissue samples. We investigated CETN2 distribution in diverse anatomical areas along the rostro-caudal neuraxis and pointed out a peculiar topography of CETN2-labeled astrocytes in humans which was not appreciable in murine tissues, where CETN2 was mostly confined to ependymal cells. As a prototypical condition with glial overproliferation, we also explored CETN2 expression in glioblastoma multiforme (GBM), reporting a focal concentration of CETN2 in neoplastic astrocytes. This study expands CETN2 localization beyond centrosomes and reveals a unique expression pattern that makes it eligible as a novel astrocytic molecular marker, thus opening new roads to glial biology and human neural conditions.
Collapse
Affiliation(s)
- Elisa Degl’Innocenti
- Fondazione Pisana per la Scienza ONLUS, San Giuliano Terme, Italy
- Department of Translational Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Tino Emanuele Poloni
- Department of Neurology and Neuropathology, Golgi-Cenci Foundation and ASP Golgi-Redaelli, Abbiategrasso, Italy
| | - Valentina Medici
- Department of Neurology and Neuropathology, Golgi-Cenci Foundation and ASP Golgi-Redaelli, Abbiategrasso, Italy
| | - Luca Recupero
- Fondazione Pisana per la Scienza ONLUS, San Giuliano Terme, Italy
| | - Claudia Dell’Amico
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy
| | | | - Ugo Borello
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy
| | | | - Marco Onorati
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy
| | - Maria Teresa Dell’Anno
- Fondazione Pisana per la Scienza ONLUS, San Giuliano Terme, Italy
- *Correspondence: Maria Teresa Dell’Anno,
| |
Collapse
|
3
|
Dráber P, Dráberová E. Dysregulation of Microtubule Nucleating Proteins in Cancer Cells. Cancers (Basel) 2021; 13:cancers13225638. [PMID: 34830792 PMCID: PMC8616210 DOI: 10.3390/cancers13225638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary The dysfunction of microtubule nucleation in cancer cells changes the overall cytoskeleton organization and cellular physiology. This review focuses on the dysregulation of the γ-tubulin ring complex (γ-TuRC) proteins that are essential for microtubule nucleation. Recent research on the high-resolution structure of γ-TuRC has brought new insight into the microtubule nucleation mechanism. We discuss the effect of γ-TuRC protein overexpression on cancer cell behavior and new drugs directed to γ-tubulin that may offer a viable alternative to microtubule-targeting agents currently used in cancer chemotherapy. Abstract In cells, microtubules typically nucleate from microtubule organizing centers, such as centrosomes. γ-Tubulin, which forms multiprotein complexes, is essential for nucleation. The γ-tubulin ring complex (γ-TuRC) is an efficient microtubule nucleator that requires additional centrosomal proteins for its activation and targeting. Evidence suggests that there is a dysfunction of centrosomal microtubule nucleation in cancer cells. Despite decades of molecular analysis of γ-TuRC and its interacting factors, the mechanisms of microtubule nucleation in normal and cancer cells remains obscure. Here, we review recent work on the high-resolution structure of γ-TuRC, which brings new insight into the mechanism of microtubule nucleation. We discuss the effects of γ-TuRC protein dysregulation on cancer cell behavior and new compounds targeting γ-tubulin. Drugs inhibiting γ-TuRC functions could represent an alternative to microtubule targeting agents in cancer chemotherapy.
Collapse
|
4
|
Mittal K, Kaur J, Jaczko M, Wei G, Toss MS, Rakha EA, Janssen EAM, Søiland H, Kucuk O, Reid MD, Gupta MV, Aneja R. Centrosome amplification: a quantifiable cancer cell trait with prognostic value in solid malignancies. Cancer Metastasis Rev 2021; 40:319-339. [PMID: 33106971 PMCID: PMC7897259 DOI: 10.1007/s10555-020-09937-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/12/2020] [Indexed: 02/07/2023]
Abstract
Numerical and/or structural centrosome amplification (CA) is a hallmark of cancers that is often associated with the aberrant tumor karyotypes and poor clinical outcomes. Mechanistically, CA compromises mitotic fidelity and leads to chromosome instability (CIN), which underlies tumor initiation and progression. Recent technological advances in microscopy and image analysis platforms have enabled better-than-ever detection and quantification of centrosomal aberrancies in cancer. Numerous studies have thenceforth correlated the presence and the degree of CA with indicators of poor prognosis such as higher tumor grade and ability to recur and metastasize. We have pioneered a novel semi-automated pipeline that integrates immunofluorescence confocal microscopy with digital image analysis to yield a quantitative centrosome amplification score (CAS), which is a summation of the severity and frequency of structural and numerical centrosome aberrations in tumor samples. Recent studies in breast cancer show that CA increases across the disease progression continuum, while normal breast tissue exhibited the lowest CA, followed by cancer-adjacent apparently normal, ductal carcinoma in situ and invasive tumors, which showed the highest CA. This finding strengthens the notion that CA could be evolutionarily favored and can promote tumor progression and metastasis. In this review, we discuss the prevalence, extent, and severity of CA in various solid cancer types, the utility of quantifying amplified centrosomes as an independent prognostic marker. We also highlight the clinical feasibility of a CA-based risk score for predicting recurrence, metastasis, and overall prognosis in patients with solid cancers.
Collapse
Affiliation(s)
- Karuna Mittal
- Department of Biology, Georgia State University, 100 Piedmont Ave, Atlanta, GA, 30303, USA
| | - Jaspreet Kaur
- Department of Biology, Georgia State University, 100 Piedmont Ave, Atlanta, GA, 30303, USA
| | - Meghan Jaczko
- Department of Biology, Georgia State University, 100 Piedmont Ave, Atlanta, GA, 30303, USA
| | - Guanhao Wei
- Department of Biology, Georgia State University, 100 Piedmont Ave, Atlanta, GA, 30303, USA
| | - Michael S Toss
- Department of Pathology, University of Nottingham and Nottingham University Hospitals, Nottingham, UK
| | - Emad A Rakha
- Department of Pathology, University of Nottingham and Nottingham University Hospitals, Nottingham, UK
| | | | - Håvard Søiland
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, Stavanger, Norway
| | - Omer Kucuk
- Winship Cancer Institute, Department of Hematology and Medical Oncology, Emory University Hospital, Atlanta, GA, USA
| | | | | | - Ritu Aneja
- Department of Biology, Georgia State University, 100 Piedmont Ave, Atlanta, GA, 30303, USA.
| |
Collapse
|
5
|
Borgenvik A, Čančer M, Hutter S, Swartling FJ. Targeting MYCN in Molecularly Defined Malignant Brain Tumors. Front Oncol 2021; 10:626751. [PMID: 33585252 PMCID: PMC7877538 DOI: 10.3389/fonc.2020.626751] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/09/2020] [Indexed: 12/21/2022] Open
Abstract
Misregulation of MYC genes, causing MYC overexpression or protein stabilization, is frequently found in malignant brain tumors highlighting their important roles as oncogenes. Brain tumors in children are the most lethal of all pediatric malignancies and the most common malignant primary adult brain tumor, glioblastoma, is still practically incurable. MYCN is one of three MYC family members and is crucial for normal brain development. It is associated with poor prognosis in many malignant pediatric brain tumor types and is focally amplified in specific adult brain tumors. Targeting MYCN has proved to be challenging due to its undruggable nature as a transcription factor and for its importance in regulating developmental programs also in healthy cells. In this review, we will discuss efforts made to circumvent the difficulty of targeting MYCN specifically by using direct or indirect measures to treat MYCN-driven brain tumors. We will further consider the mechanism of action of these measures and suggest which molecularly defined brain tumor patients that might benefit from MYCN-directed precision therapies.
Collapse
Affiliation(s)
- Anna Borgenvik
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Matko Čančer
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Sonja Hutter
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Fredrik J Swartling
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| |
Collapse
|
6
|
The therapeutic potential of Aurora kinases targeting in glioblastoma: from preclinical research to translational oncology. J Mol Med (Berl) 2020; 98:495-512. [PMID: 32219470 DOI: 10.1007/s00109-020-01895-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/28/2020] [Accepted: 03/03/2020] [Indexed: 12/21/2022]
Abstract
Glioblastoma is the most common aggressive primary brain tumor. Standard care includes maximal safe surgical resection, radiation, and chemotherapy with temozolomide. However, the impact of this therapeutic approach on patient survival is disappointing and poor outcomes are frequently observed. Therefore, new therapeutic targets are needed to treat this potentially deadly tumor. Aurora kinases are one of today's most sought-after classes of therapeutic targets to glioblastoma therapy. They are a family of proteins composed of three members: Aurora-A, Aurora-B, and Aurora-C that play different roles in the cell division through regulation of chromosome segregation. Deregulation of these genes has been reported in glioblastoma and a progressive number of studies have shown that inhibition of these proteins could be a promising strategy for the treatment of this tumor. This review discusses the preclinical and early clinical findings on the potential use of the Aurora kinases as new targets for the treatment of glioblastoma. KEY MESSAGES: GBM is a very aggressive tumor with limited therapeutic options. Aurora kinases are a family of serine/threonine kinases implicated in GBM pathology. Aurora kinases are critical for glioblastoma cell growth, apoptosis, and chemoresistance. Inhibition of Aurora kinases has a synergistic or sensitizing effect with chemotherapy drugs, radiotherapy, or with other targeted molecules in GBM. Several Aurora kinase inhibitors are currently in clinical trials.
Collapse
|
7
|
Ryu J, Pyo J, Lee CW, Kim JE. An Aurora kinase inhibitor, AMG900, inhibits glioblastoma cell proliferation by disrupting mitotic progression. Cancer Med 2018; 7:5589-5603. [PMID: 30221846 PMCID: PMC6246935 DOI: 10.1002/cam4.1771] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/09/2018] [Accepted: 08/17/2018] [Indexed: 12/18/2022] Open
Abstract
The Aurora kinase family of serine/threonine protein kinases comprises Aurora A, B, and C and plays an important role in mitotic progression. Several inhibitors of Aurora kinase have been developed as anti‐cancer therapeutics. Here, we examined the effects of a pan‐Aurora kinase inhibitor, AMG900, against glioblastoma cells. AMG900 inhibited proliferation of A172, U‐87MG, and U‐118MG glioblastoma cells by upregulating p53 and p21 and subsequently inducing cell cycle arrest and senescence. Abnormal cell cycle progression was triggered by dysregulated mitosis. Mitosis was prolonged due to a defect in mitotic spindle assembly. Despite the presence of an unattached kinetochore, BubR1, a component of the spindle assembly checkpoint, was not recruited. In addition, Aurora B was not recruited to central spindle at anaphase. Abnormal mitotic progression resulted in accumulation of multinuclei and micronuclei, a type of chromosome missegregation, and ultimately inhibited cell survival. Therefore, the data suggest that AMG900‐mediated inhibition of Aurora kinase is a potential anti‐cancer therapy for glioblastoma.
Collapse
Affiliation(s)
- Jaewook Ryu
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Jaehyuk Pyo
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Chang-Woo Lee
- Department of Molecular Cell Biology, School of Medicine, Sungkyunkwan University, Suwon, Korea
| | - Ja-Eun Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea.,Department of Pharmacology, School of Medicine, Kyung Hee University, Seoul, Korea
| |
Collapse
|
8
|
Kurokawa C, Geekiyanage H, Allen C, Iankov I, Schroeder M, Carlson B, Bakken K, Sarkaria J, Ecsedy JA, D'Assoro A, Friday B, Galanis E. Alisertib demonstrates significant antitumor activity in bevacizumab resistant, patient derived orthotopic models of glioblastoma. J Neurooncol 2016; 131:41-48. [PMID: 27816996 DOI: 10.1007/s11060-016-2285-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/09/2016] [Indexed: 10/20/2022]
Abstract
Aurora A kinase (AURKA), a member of the serine/threonine kinase family, plays a critical role in cell division, and it is widely overexpressed in a variety of tumors including glioblastoma (GBM). Alisertib (MLN8237) is an orally administered selective AURKA inhibitor with potent antiproliferative activity, currently undergoing clinical testing in different tumor types. In vitro evaluation of alisertib against the primary GBM lines, GBM6, GBM10, GBM12 and GBM39 showed significant antitumor activity with IC50s ranging between 30 and 95 nM. Orthotopic xenografts of GBM10 and the bevacizumab resistant lines GBM6 and GBM39 were established by implantating 3 × 105 cells in the caudate nucleus of nude mice; animals were randomized to treatment with either alisertib 30 mg/kg/day or vehicle. In all three models, treatment with alisertib resulted in a statistically significant prolongation of survival (p < 0.0001). In addition, alisertib administration in these mice decreased phosphorylated aurora-A, induced mitotic arrest and significantly decreased histone H3 phosphorylation in tumors. In conclusion, alisertib displays significant antitumor activity against primary GBM lines and xenografts, including patient derived GBM lines resistant to bevacizumab; these data support clinical translation in GBM.
Collapse
Affiliation(s)
- C Kurokawa
- Department of Molecular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - H Geekiyanage
- Department of Molecular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - C Allen
- Department of Molecular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - I Iankov
- Department of Molecular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - M Schroeder
- Department of Radiation Oncology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - B Carlson
- Department of Radiation Oncology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - K Bakken
- Department of Radiation Oncology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - J Sarkaria
- Department of Radiation Oncology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - J A Ecsedy
- Translational Medicine, Millennium Pharmaceuticals, Inc. (A Wholly Owned Subsidiary of Takeda Pharmaceutical Company Limited), Cambridge, MA, 02139, USA
| | - A D'Assoro
- Department of Molecular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - B Friday
- Essentia Health Oncology, 420 E 1st St, Duluth, MN, 55805, USA
| | - E Galanis
- Departments of Oncology and Molecular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
| |
Collapse
|
9
|
Willems E, Lombard A, Dedobbeleer M, Goffart N, Rogister B. The Unexpected Roles of Aurora A Kinase in Gliobastoma Recurrences. Target Oncol 2016; 12:11-18. [DOI: 10.1007/s11523-016-0457-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
10
|
Overexpression and Nucleolar Localization of γ-Tubulin Small Complex Proteins GCP2 and GCP3 in Glioblastoma. J Neuropathol Exp Neurol 2015; 74:723-42. [PMID: 26079448 DOI: 10.1097/nen.0000000000000212] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The expression, cellular distribution, and subcellular sorting of the microtubule (MT)-nucleating γ-tubulin small complex (γTuSC) proteins, GCP2 and GCP3, were studied in human glioblastoma cell lines and in clinical tissue samples representing all histologic grades of adult diffuse astrocytic gliomas (n = 54). Quantitative real-time polymerase chain reaction revealed a significant increase in the expression of GCP2 and GCP3 transcripts in glioblastoma cells versus normal human astrocytes; these were associated with higher amounts of both γTuSC proteins. GCP2 and GCP3 were concentrated in the centrosomes in interphase glioblastoma cells, but punctate and diffuse localizations were also detected in the cytosol and nuclei/nucleoli. Nucleolar localization was fixation dependent. GCP2 and GCP3 formed complexes with γ-tubulin in the nucleoli as confirmed by reciprocal immunoprecipitation experiments and immunoelectron microscopy. GCP2 and GCP3 depletion caused accumulation of cells in G2/M and mitotic delay but did not affect nucleolar integrity. Overexpression of GCP2 antagonized the inhibitory effect of the CDK5 regulatory subunit-associated tumor suppressor protein 3 (C53) on DNA damage G2/M checkpoint activity. Tumor cell GCP2 and GCP3 immunoreactivity was significantly increased over that in normal brains in glioblastoma samples; it was also associated with microvascular proliferation. These findings suggest that γTuSC protein dysregulation in glioblastomas may be linked to altered transcriptional checkpoint activity or interaction with signaling pathways associated with a malignant phenotype.
Collapse
|
11
|
Venghateri JB, Jindal B, Panda D. The centrosome: a prospective entrant in cancer therapy. Expert Opin Ther Targets 2015; 19:957-72. [PMID: 25787715 DOI: 10.1517/14728222.2015.1018823] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION The centrosome plays an essential role in the cell cycle. The centrosome and its associated proteins assist in nucleating and organizing microtubules. A structural or a functional aberration in the centrosome is known to cause abnormal cell proliferation leading to tumors. Therefore, the centrosome is considered as a promising anti-cancer target. AREAS COVERED This review begins with a brief introduction to the centrosome and its role in the cell cycle. We elaborate on the centrosome-associated proteins that regulate microtubule dynamics. In addition, we discuss the centrosomal protein kinase targets such as cyclin-dependent, polo-like and aurora kinases. Inhibitors targeting these kinases are undergoing clinical trials for cancer chemotherapy. Further, we shed light on new approaches to target the centrosomal proteins for cancer therapy. EXPERT OPINION Insights into the functioning of the centrosomal proteins will be extremely beneficial in validating the centrosome as a target in cancer therapy. New strategies either as a single entity or in combination with current chemotherapeutic agents should be researched or exploited to reveal the promises that the centrosome holds for future cancer therapy.
Collapse
Affiliation(s)
- Jubina B Venghateri
- Indian Institute of Technology Bombay, IITB-Monash Research Academy , Powai, Mumbai 400076 , India
| | | | | |
Collapse
|
12
|
Katsetos CD, Reginato MJ, Baas PW, D'Agostino L, Legido A, Tuszyn Ski JA, Dráberová E, Dráber P. Emerging microtubule targets in glioma therapy. Semin Pediatr Neurol 2015; 22:49-72. [PMID: 25976261 DOI: 10.1016/j.spen.2015.03.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.
Collapse
Affiliation(s)
- Christos D Katsetos
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA; Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, PA.
| | - Mauricio J Reginato
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA
| | - Luca D'Agostino
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Agustin Legido
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Jack A Tuszyn Ski
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| |
Collapse
|
13
|
Telentschak S, Soliwoda M, Nohroudi K, Addicks K, Klinz FJ. Cytokinesis failure and successful multipolar mitoses drive aneuploidy in glioblastoma cells. Oncol Rep 2015; 33:2001-8. [PMID: 25625503 DOI: 10.3892/or.2015.3751] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/22/2014] [Indexed: 11/05/2022] Open
Abstract
Glioblastoma (GB) is the most frequent human brain tumor and is associated with a poor prognosis. Multipolar mitosis and spindles have occasionally been observed in cultured glioblastoma cells and in glioblastoma tissues, but their mode of origin and relevance have remained unclear. In the present study, we investigated a novel GB cell line (SGB4) exhibiting mitotic aberrations and established a functional link between cytokinesis failure, centrosome amplification, multipolar mitosis and aneuploidy in glioblastoma. Long-term live cell imaging showed that >3% of mitotic SGB4 cells underwent multipolar mitosis (tripolar>tetrapolar>pentapolar). A significant amount of daugther cells generated by multipolar mitosis were viable and completed several rounds of mitosis. Pedigree analysis of mitotic events revealed that in many cases a bipolar mitosis with failed cytokinesis occurred prior to a multipolar mitosis. Additionally, we observed that SGB4 cells were also able to undergo a bipolar mitosis after failed cytokinesis. Colchicine-induced mitotic arrest and metaphase spreads demonstrated that SGB4 cells had a modal chromosome number of 58 ranging from 23 to 170. Approximately 82% of SGB4 cells were hyperdiploid (47-57 chromosomes) or hypotriploid (58-68 chromosomes). In conclusion, SGB4 cells passed through multipolar cell divisions and generated viable progeny by reductive mitoses. Our results identified cytokinesis failure occurring before and after multipolar or bipolar mitoses as important mechanisms to generate chromosomal heterogeneity in glioblastoma cells.
Collapse
Affiliation(s)
- Sergej Telentschak
- Department I of Anatomy, University of Cologne, D-50931 Cologne, Germany
| | - Mark Soliwoda
- Department I of Anatomy, University of Cologne, D-50931 Cologne, Germany
| | - Klaus Nohroudi
- Department I of Anatomy, University of Cologne, D-50931 Cologne, Germany
| | - Klaus Addicks
- Department I of Anatomy, University of Cologne, D-50931 Cologne, Germany
| | - Franz-Josef Klinz
- Department I of Anatomy, University of Cologne, D-50931 Cologne, Germany
| |
Collapse
|
14
|
Olmsted ZT, Colliver AG, Riehlman TD, Paluh JL. Kinesin-14 and kinesin-5 antagonistically regulate microtubule nucleation by γ-TuRC in yeast and human cells. Nat Commun 2014; 5:5339. [PMID: 25348260 PMCID: PMC4220466 DOI: 10.1038/ncomms6339] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 09/20/2014] [Indexed: 02/07/2023] Open
Abstract
Bipolar spindle assembly is a critical control point for initiation of mitosis through nucleation and organization of spindle microtubules and is regulated by kinesin-like proteins. In fission yeast, the kinesin-14 Pkl1 binds the γ-tubulin ring complex (γ-TuRC) microtubule-organizing centre at spindle poles and can alter its structure and function. Here we show that kinesin-14 blocks microtubule nucleation in yeast and reveal that this inhibition is countered by the kinesin-5 protein, Cut7. Furthermore, we demonstrate that Cut7 binding to γ-TuRC and the Cut7 BimC domain are both required for inhibition of Pkl1. We also demonstrate that a yeast kinesin-14 peptide blocks microtubule nucleation in two human breast cancer cell lines, suggesting that this mechanism is evolutionarily conserved. In conclusion, using genetic, biochemical and cell biology approaches we uncover antagonistic control of microtubule nucleation at γ-TuRC by two kinesin-like proteins, which may represent an attractive anti-mitotic target for cancer therapies. Mitotic spindle assembly requires strict control of microtubule nucleation by γ-tubulin ring complexes. Olmsted et al. report that the kinesin-like proteins Pkl1 and Cut7 antagonistically regulate nucleation in fission yeast, and show that a Pkl1 peptide blocks spindle assembly in human cancer cells.
Collapse
Affiliation(s)
- Zachary T Olmsted
- State University of New York Polytechnic Institute, College of Nanoscale Science, Nanobioscience Constellation, Albany, New York 12203, USA
| | - Andrew G Colliver
- State University of New York Polytechnic Institute, College of Nanoscale Science, Nanobioscience Constellation, Albany, New York 12203, USA
| | - Timothy D Riehlman
- State University of New York Polytechnic Institute, College of Nanoscale Science, Nanobioscience Constellation, Albany, New York 12203, USA
| | - Janet L Paluh
- State University of New York Polytechnic Institute, College of Nanoscale Science, Nanobioscience Constellation, Albany, New York 12203, USA
| |
Collapse
|
15
|
Mannino M, Gomez-Roman N, Hochegger H, Chalmers AJ. Differential sensitivity of Glioma stem cells to Aurora kinase A inhibitors: implications for stem cell mitosis and centrosome dynamics. Stem Cell Res 2014; 13:135-43. [PMID: 24879067 PMCID: PMC4085484 DOI: 10.1016/j.scr.2014.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 04/01/2014] [Accepted: 05/02/2014] [Indexed: 11/28/2022] Open
Abstract
Glioma stem-cell-like cells are considered to be responsible for treatment resistance and tumour recurrence following chemo-radiation in glioblastoma patients, but specific targets by which to kill the cancer stem cell population remain elusive. A characteristic feature of stem cells is their ability to undergo both symmetric and asymmetric cell divisions. In this study we have analysed specific features of glioma stem cell mitosis. We found that glioma stem cells appear to be highly prone to undergo aberrant cell division and polyploidization. Moreover, we discovered a pronounced change in the dynamic of mitotic centrosome maturation in these cells. Accordingly, glioma stem cell survival appeared to be strongly dependent on Aurora A activity. Unlike differentiated cells, glioma stem cells responded to moderate Aurora A inhibition with spindle defects, polyploidization and a dramatic increase in cellular senescence, and were selectively sensitive to Aurora A and Plk1 inhibitor treatment. Our study proposes inhibition of centrosomal kinases as a novel strategy to selectively target glioma stem cells.
Collapse
Affiliation(s)
- Mariella Mannino
- Genome Damage and Stability Centre, University of Sussex, Brighton BN19RQ, UK
| | | | - Helfrid Hochegger
- Genome Damage and Stability Centre, University of Sussex, Brighton BN19RQ, UK.
| | - Anthony J Chalmers
- Institute of Cancer Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| |
Collapse
|
16
|
Tsai HP, Tsai CY, Lieu AS, Chai CY, Kwan AL, Howng SL, Loh JK. Association of Aurora A and gamma-tubulin expression in astrocytomas and patient survival. Neurol Res 2014; 36:746-51. [PMID: 24620973 DOI: 10.1179/1743132813y.0000000310] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES The purpose was to evaluate the association of Aurora A and gamma-tubulin expression with disease characteristics and survival in patients with astrocytoma. METHODS This is a retrospective study of patients who had surgical specimens that were pathologically diagnosed as astrocytoma. The expression level of Aurora A and gamma-tubulin in tumor tissue was evaluated by immunohistochemistry. Clinical information, Karnofsky performance status scale, and survival status of patients were collected. RESULTS We found that high protein levels of gamma-tubulin or Aurora A were associated with patients 45 years of age, high tumor grade, more advanced non-fully resectable tumors, and poorer survival status. The survival time for patients whose tumors had high gamma-tubulin and Aurora A expression was about 12 months compared with approximately 41 months for patients with low levels of expression of these proteins. Poor patient performance status following resection was also associated with high levels of gamma-tubulin and Aurora A expression. DISCUSSION The expression levels of gamma-tubulin or Aurora A kinase were associated with patients' age, astrocytoma grade, respectability, as well as patient survival and performance. These findings support the idea that these factors may potentially be important prognostic indicators for patients with astrocytomas.
Collapse
|
17
|
Ruban A, Berkutzki T, Cooper I, Mohar B, Teichberg VI. Blood glutamate scavengers prolong the survival of rats and mice with brain-implanted gliomas. Invest New Drugs 2012; 30:2226-35. [PMID: 22392507 PMCID: PMC3484283 DOI: 10.1007/s10637-012-9799-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Accepted: 01/10/2012] [Indexed: 10/28/2022]
Abstract
L-Glutamate (Glu) plays a crucial role in the growth of malignant gliomas. We have established the feasibility of accelerating a naturally occurring brain to-blood Glu efflux by decreasing blood Glu levels with intravenous oxaloacetate, the respective Glu co-substrate of the blood resident enzyme humane glutamate–oxaloacetate transaminase(hGOT). We wished to demonstrate that blood Glu scavenging provides neuroprotection in the case of glioma.We now describe the neuroprotective effects of blood Glu scavenging in a fatal condition such as brain-implanted C6 glioma in rats and brain-implanted human U87 MG glioma in nude mice. Rat (C-6) or human (U87) glioma cells were grafted stereotactically in the brain of rats or mice. After development of tumors, the animals were drinking oxaloacetate with or without injections of hGOT. In addition, mice were treated with combination treatment, which included drinking oxaloacetate with intracutaneous injections of hGOT and intraperitoneal injection of Temozolomide. Animals drinking oxaloacetate with or without injections of hGOT displayed a smaller tumor volume, reduced invasiveness and prolonged survival than control animals drinking saline. These effects were significantly enhanced by Temozolomide in mice, which increased survival by 237%. This is the first demonstration of blood Glu scavenging in brain cancer, and because of its safety, is likely to be of clinical significance for the future treatment of human gliomas. As we demonstrated, the blood glutamate scavenging treatment in combination with TMZ could be a good candidate or as an alternative treatment to the patients that do not respond to TMZ.
Collapse
Affiliation(s)
- Angela Ruban
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel.
| | | | | | | | | |
Collapse
|
18
|
Ribeiro-Varandas E, Viegas W, Sofia Pereira H, Delgado M. Bisphenol A at concentrations found in human serum induces aneugenic effects in endothelial cells. Mutat Res 2012; 751:27-33. [PMID: 23142537 DOI: 10.1016/j.mrgentox.2012.10.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 08/17/2012] [Accepted: 10/21/2012] [Indexed: 12/21/2022]
Abstract
Bisphenol A (BPA) is an endocrine disrupting chemical to which humans are exposed. Continuous environmental exposure to BPA leads to its detection in the majority of individuals from developed countries, with serum concentrations ranging from 0.5 to 10ng/ml in the general population and much higher when associated with occupational exposure. In this work, human umbilical vascular endothelial cells (HUVEC) and human colon adenocarcinona (HT29) cell lines were used to represent endothelial and digestive-tract tissues, which are in direct contact to BPA in vivo. Our results demonstrate that BPA has cell-type differential effects. Notably, BPA concentrations commonly found in humans induce micronucleus formation and interfere with cell-division processes in endothelial cells, resulting in mitotic abnormalities. We also found that BPA induces up-regulation of two genes encoding proteins associated with chromosome segregation, namely CDCA8 (borealin/cell division cycle A8) and SGOL2 (shugoshin-like2). Taken together, the aneugenic effects observed in endothelial cells (HUVECs) substantiate increasing concerns about BPA exposure at levels currently detected in humans.
Collapse
Affiliation(s)
- Edna Ribeiro-Varandas
- CBAA-Genetics, Instituto Superior de Agronomia, Technical University of Lisbon, Portugal
| | | | | | | |
Collapse
|
19
|
Loh JK, Lieu AS, Chou CH, Lin CC, Yang MC, Lin FY, Hong YR, Howng SL. Differential expression of centrosome-associated proteins in human brain tumors: a possible role of hNinein isoform 6 in cell differentiation. Biofactors 2012; 38:470-7. [PMID: 23047184 DOI: 10.1002/biof.1053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 09/02/2012] [Indexed: 01/02/2023]
Abstract
Dysregulated centrosomal expression has been observed in high grade gliomas. Thus, this study aimed to examine the expression of Aurora family kinase and various centrosomal proteins, including centrin, γ-tubulin, and hNinein isoforms, in human brain tumors, including 29 meningiomas, 34 astrocytomas, 6 pituitary adenomas, and 6 metastatic tumors. mRNA expression was evaluated using reverse transcription polymerase chain reaction. The role of hNinein isoform 6 expression in cell differentiation was assessed in BrdU-treated IMR-32 cells. Differential expression of centrosomal proteins of brain tumors and cell lines was observed. Specifically, centrin 2 and centrin 3 expression levels were classified as moderate or abundant in >97% of samples in the meningioma group, 63% of astrocytomas, >83% of metastatic and pituitary tumors. Alternatively, hNinein isoform 6 expression was only detected in normal brain and astrocytoma tumors (17/34); however, it was not expressed in meningioma (0/29), metastatic tumors (0/6) (P < 0.001). Of the six neuroblastoma cell lines analyzed only IMR-32 cells expressed hNinein isoform 6. Furthermore, downregulated expression of hNinein isoform 6 and upregulation of γ-tubulin was correlated to astrocytoma tumor grade (P < 0.001). Increased hNinein isoform 6 mRNA expression was observed in response to BrdU treatment, and its expression was greater in teratomas as compared to embryonic stem cells. Further studies are necessary to determine if hNinein isoform 6 functions as a tumor-suppressor gene in brain tumors. Differential centrosomal protein expression may result in altered centrosome function that is observed the in progression of various brain tumors.
Collapse
Affiliation(s)
- Joon-Khim Loh
- Department of Neurosurgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | | | | | | | | | | | | | | |
Collapse
|
20
|
|
21
|
Ruban A, Berkutzki T, Cooper I, Mohar B, Teichberg VI. Blood glutamate scavengers prolong the survival of rats and mice with brain-implanted gliomas. Invest New Drugs 2012; 30:2226-2235. [PMID: 22297683 PMCID: PMC3484283 DOI: 10.1007/s10637-012-9794-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Accepted: 01/10/2012] [Indexed: 11/29/2022]
Abstract
L-Glutamate (Glu) plays a crucial role in the growth of malignant gliomas. We have established the feasibility of accelerating a naturally occurring brain to-blood Glu efflux by decreasing blood Glu levels with intravenous oxaloacetate, the respective Glu co-substrate of the blood resident enzyme humane glutamate-oxaloacetate transaminase (hGOT). We wished to demonstrate that blood Glu scavenging provides neuroprotection in the case of glioma. We now describe the neuroprotective effects of blood Glu scavenging in a fatal condition such as brain-implanted C6 glioma in rats and brain-implanted human U87 MG glioma in nude mice. Rat (C-6) or human (U87) glioma cells were grafted stereotactically in the brain of rats or mice. After development of tumors, the animals were drinking oxaloacetate with or without injections of hGOT. In addition, mice were treated with combination treatment, which included drinking oxaloacetate with intracutaneous injections of hGOT and intraperitoneal injection of Temozolomide. Animals drinking oxaloacetate with or without injections of hGOT displayed a smaller tumor volume, reduced invasiveness and prolonged survival than control animals drinking saline. These effects were significantly enhanced by Temozolomide in mice, which increased survival by 237%. This is the first demonstration of blood Glu scavenging in brain cancer, and because of its safety, is likely to be of clinical significance for the future treatment of human gliomas. As we demonstrated, the blood glutamate scavenging treatment in combination with TMZ could be a good candidate or as an alternative treatment to the patients that do not respond to TMZ.
Collapse
Affiliation(s)
- Angela Ruban
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 76100, Israel,
| | | | | | | | | |
Collapse
|
22
|
γ-Tubulin 2 nucleates microtubules and is downregulated in mouse early embryogenesis. PLoS One 2012; 7:e29919. [PMID: 22235350 PMCID: PMC3250491 DOI: 10.1371/journal.pone.0029919] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/06/2011] [Indexed: 01/09/2023] Open
Abstract
γ-Tubulin is the key protein for microtubule nucleation. Duplication of the γ-tubulin gene occurred several times during evolution, and in mammals γ-tubulin genes encode proteins which share ∼97% sequence identity. Previous analysis of Tubg1 and Tubg2 knock-out mice has suggested that γ-tubulins are not functionally equivalent. Tubg1 knock-out mice died at the blastocyst stage, whereas Tubg2 knock-out mice developed normally and were fertile. It was proposed that γ-tubulin 1 represents ubiquitous γ-tubulin, while γ-tubulin 2 may have some specific functions and cannot substitute for γ-tubulin 1 deficiency in blastocysts. The molecular basis of the suggested functional difference between γ-tubulins remains unknown. Here we show that exogenous γ-tubulin 2 is targeted to centrosomes and interacts with γ-tubulin complex proteins 2 and 4. Depletion of γ-tubulin 1 by RNAi in U2OS cells causes impaired microtubule nucleation and metaphase arrest. Wild-type phenotype in γ-tubulin 1-depleted cells is restored by expression of exogenous mouse or human γ-tubulin 2. Further, we show at both mRNA and protein levels using RT-qPCR and 2D-PAGE, respectively, that in contrast to Tubg1, the Tubg2 expression is dramatically reduced in mouse blastocysts. This indicates that γ-tubulin 2 cannot rescue γ-tubulin 1 deficiency in knock-out blastocysts, owing to its very low amount. The combined data suggest that γ-tubulin 2 is able to nucleate microtubules and substitute for γ-tubulin 1. We propose that mammalian γ-tubulins are functionally redundant with respect to the nucleation activity.
Collapse
|
23
|
Chan JY. A clinical overview of centrosome amplification in human cancers. Int J Biol Sci 2011; 7:1122-44. [PMID: 22043171 PMCID: PMC3204404 DOI: 10.7150/ijbs.7.1122] [Citation(s) in RCA: 272] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 10/06/2011] [Indexed: 01/11/2023] Open
Abstract
The turn of the 21st century had witnessed a surge of interest in the centrosome and its causal relation to human cancer development - a postulate that has existed for almost a century. Centrosome amplification (CA) is frequently detected in a growing list of human cancers, both solid and haematological, and is a candidate "hallmark" of cancer cells. Several lines of evidence support the progressive involvement of CA in the transition from early to advanced stages of carcinogenesis, being also found in pre-neoplastic lesions and even in histopathologically-normal tissue. CA constitutes the major mechanism leading to chromosomal instability and aneuploidy, via the formation of multipolar spindles and chromosomal missegregation. Clinically, CA may translate to a greater risk for initiation of malignant transformation, tumour progression, chemoresistance and ultimately, poor patient prognosis. As mechanisms underlying CA are progressively being unravelled, the centrosome has emerged as a novel candidate target for cancer treatment. This Review summarizes mainly the clinical studies performed to date focusing on the mechanisms underlying CA in human neoplasia, and highlights the potential utility of centrosomes in the diagnosis, prognosis and treatment of human cancers.
Collapse
|