1
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Kaplan AR, Glazer PM. Impact of hypoxia on DNA repair and genome integrity. Mutagenesis 2021; 35:61-68. [PMID: 31282537 DOI: 10.1093/mutage/gez019] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/24/2019] [Indexed: 12/12/2022] Open
Abstract
Hypoxia is a hallmark of the tumour microenvironment with profound effects on tumour biology, influencing cancer progression, the development of metastasis and patient outcome. Hypoxia also contributes to genomic instability and mutation frequency by inhibiting DNA repair pathways. This review summarises the diverse mechanisms by which hypoxia affects DNA repair, including suppression of homology-directed repair, mismatch repair and base excision repair. We also discuss the effects of hypoxia mimetics and agents that induce hypoxia on DNA repair, and we highlight areas of potential clinical relevance as well as future directions.
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Affiliation(s)
- Alanna R Kaplan
- Department of Therapeutic Radiology, New Haven, CT, USA.,Department of Experimental Pathology, New Haven, CT, USA
| | - Peter M Glazer
- Department of Therapeutic Radiology, New Haven, CT, USA.,Department of Genetics, Yale University, New Haven, CT, USA
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2
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Efficacy of Surface-Modified PLGA Nanoparticles as a Function of Cervical Cancer Type. Pharm Res 2019; 36:66. [PMID: 30868271 DOI: 10.1007/s11095-019-2602-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/04/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE Hypovascularization of cervical tumors, coupled with intrinsic and acquired drug resistance, has contributed to marginal therapeutic outcomes by hindering chemotherapeutic transport and efficacy. Recently, the heterogeneous penetration and distribution of cell penetrating peptide (CPP, here MPG) and polyethylene glycol (PEG) modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were evaluated as a function of tumor type and morphology in cervical cancer spheroids modeling hypovascularized tumor nodules. Building upon this work, this study investigates the efficacy imparted by surface-modified Doxorubicin-loaded NPs transported into hypovascularized tissue. METHODS NP efficacy was measured in HeLa, CaSki, and SiHa cells. NP internalization and association, and associated cell viability, were determined in monolayer and spheroid models. RESULTS MPG and PEG-NP co-treatment was most efficacious in HeLa cells, while PEG NPs were most efficacious in CaSki cells. NP surface-modifications were unable to improve efficacy, relative to unmodified NPs, in SiHa cells. CONCLUSIONS The results highlight the dependence of efficacy on tumor type and the associated microenvironment. The results further relate previous NP transport studies to efficacy, as a function of surface-modification and cell type. Longer-term, this information may help guide the design of NP-mediated strategies to maximize efficacy based on patient-specific cervical tumor origin and characteristics.
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3
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Jo Y, Choi N, Kim K, Koo HJ, Choi J, Kim HN. Chemoresistance of Cancer Cells: Requirements of Tumor Microenvironment-mimicking In Vitro Models in Anti-Cancer Drug Development. Am J Cancer Res 2018; 8:5259-5275. [PMID: 30555545 PMCID: PMC6276092 DOI: 10.7150/thno.29098] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 10/04/2018] [Indexed: 01/09/2023] Open
Abstract
For decades, scientists have been using two-dimensional cell culture platforms for high-throughput drug screening of anticancer drugs. Growing evidence indicates that the results of anti-cancer drug screening vary with the cell culture microenvironment, and this variation has been proposed as a reason for the high failure rate of clinical trials. Since the culture condition-dependent drug sensitivity of anti-cancer drugs may negatively impact the identification of clinically effective drug candidates, more reliable in vitro cancer platforms are urgently needed. In this review article, we provide an overview of how cell culture conditions can alter drug efficacy and highlight the importance of developing more reliable cancer drug testing platforms for use in the drug discovery process. The environmental factors that can alter drug delivery and efficacy are reviewed. Based on these observations of chemoresistant tumor physiology, we summarize the recent advances in the fabrication of in vitro cancer models and the model-dependent cytotoxicity of anti-cancer drugs, with a particular focus on engineered environmental factors in these platforms. It is believed that more physiologically relevant cancer models can revolutionize the drug discovery process.
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4
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Nikolaou M, Pavlopoulou A, Georgakilas AG, Kyrodimos E. The challenge of drug resistance in cancer treatment: a current overview. Clin Exp Metastasis 2018; 35:309-318. [DOI: 10.1007/s10585-018-9903-0] [Citation(s) in RCA: 248] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 05/16/2018] [Indexed: 12/14/2022]
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5
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Scanlon SE, Hegan DC, Sulkowski PL, Glazer PM. Suppression of homology-dependent DNA double-strand break repair induces PARP inhibitor sensitivity in VHL-deficient human renal cell carcinoma. Oncotarget 2018; 9:4647-4660. [PMID: 29435132 PMCID: PMC5797003 DOI: 10.18632/oncotarget.23470] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 11/28/2017] [Indexed: 11/25/2022] Open
Abstract
The von Hippel-Lindau (VHL) tumor suppressor gene is inactivated in the vast majority of human clear cell renal carcinomas. The pathogenesis of VHL loss is currently best understood to occur through stabilization of the hypoxia-inducible factors, activation of hypoxia-induced signaling pathways, and transcriptional reprogramming towards a pro-angiogenic and pro-growth state. However, hypoxia also drives other pro-tumorigenic processes, including the development of genomic instability via down-regulation of DNA repair gene expression. Here, we find that DNA repair genes involved in double-strand break repair by homologous recombination (HR) and in mismatch repair, which are down-regulated by hypoxic stress, are decreased in VHL-deficient renal cancer cells relative to wild type VHL-complemented cells. Functionally, this gene repression is associated with impaired DNA double-strand break repair in VHL-deficient cells, as determined by the persistence of ionizing radiation-induced DNA double-strand breaks and reduced repair activity in a homology-dependent plasmid reactivation assay. Furthermore, VHL deficiency conferred increased sensitivity to PARP inhibitors, analogous to the synthetic lethality observed between hypoxia and these agents. Finally, we discovered a correlation between VHL inactivation and reduced HR gene expression in a large panel of human renal carcinoma samples. Together, our data elucidate a novel connection between VHL-deficient renal carcinoma and hypoxia-induced down-regulation of DNA repair, and identify potential opportunities for targeting DNA repair defects in human renal cell carcinoma.
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Affiliation(s)
- Susan E. Scanlon
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
- Department of Experimental Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Denise C. Hegan
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Parker L. Sulkowski
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Peter M. Glazer
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
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6
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Qi X, Wong BL, Lau SH, Ng KTP, Kwok SY, Kin-Wai Sun C, Tzang FC, Shao Y, Li CX, Geng W, Ling CC, Ma YY, Liu XB, Liu H, Liu J, Yeung WH, Lo CM, Man K. A hemoglobin-based oxygen carrier sensitized Cisplatin based chemotherapy in hepatocellular carcinoma. Oncotarget 2017; 8:85311-85325. [PMID: 29156721 PMCID: PMC5689611 DOI: 10.18632/oncotarget.19672] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/11/2017] [Indexed: 12/13/2022] Open
Abstract
Background and Objective Our previous study showed that liver graft injury not only promotes tumor recurrence, but also induces chemoresistance in recurrent HCC after liver transplantation. Recently, we found that the hemoglobin-based oxygen carrier“YQ23” significantly ameliorates hepatic IR injury and prevent tumor recurrence. Here, we intended to explore the novel therapeutic strategy using oxygen carrier “YQ23”to sensitize chemotherapy in HCC. Methods To investigate the role of YQ23 combined with Cisplatin, the proliferation of HCC cells was examined under combined treatment by MTT and colony formation. To explore the effect of YQ23 on sensitization of Cisplatin based chemotherapy, the orthotopic liver cancer model was established. To characterize the delivery of YQ23 in tumor tissue, the intravital imaging system was applied for longitudinal observation in ectopic liver cancer model. The distribution of YQ23 was examined by IVIS spectrum. Results YQ23 significantly suppressed the proliferation of HCC cells under Cisplatin treatment in a dose and time dependent manner. Moreover, YQ23 administration significantly sensitized Cisplatin based chemotherapy in orthotopic liver cancer model. Down-regulation of DHFR may be one of the reasons for YQ23 sensitizing Cisplatin based chemotherapy. Real-time intravital imaging showed that YQ23 accumulated in the tumor tissue and maintained as long as 3 days in ectopic liver cancer model. The IVIS spectrum examination showed that YQ23 distributed mainly at liver and bladder within the first 36 hours after administration in orthotopic liver cancer model. Conclusion YQ23 treatment may be a potential therapeutic strategy to sensitize chemotherapy in HCC.
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Affiliation(s)
- Xiang Qi
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Bing L Wong
- New β Innovation Limited, 18/F Chevalier Commercial Centre, Hong Kong, China
| | - Sze Hang Lau
- New β Innovation Limited, 18/F Chevalier Commercial Centre, Hong Kong, China
| | - Kevin Tak-Pan Ng
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Sui Yi Kwok
- New β Innovation Limited, 18/F Chevalier Commercial Centre, Hong Kong, China
| | - Chris Kin-Wai Sun
- New β Innovation Limited, 18/F Chevalier Commercial Centre, Hong Kong, China
| | - Fei Chuen Tzang
- New β Innovation Limited, 18/F Chevalier Commercial Centre, Hong Kong, China
| | - Yan Shao
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Chang Xian Li
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Wei Geng
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Chang Chun Ling
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Yuen Yuen Ma
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Xiao Bing Liu
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Hui Liu
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Jiang Liu
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Wai Ho Yeung
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Chung Mau Lo
- Department of Surgery, The University of Hong Kong, Hong Kong, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Kwan Man
- Department of Surgery, The University of Hong Kong, Hong Kong, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
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7
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Lucas AT, Price LS, Schorzman A, Zamboni WC. Complex effects of tumor microenvironment on the tumor disposition of carrier-mediated agents. Nanomedicine (Lond) 2017; 12:2021-2042. [PMID: 28745129 DOI: 10.2217/nnm-2017-0101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Major advances in carrier-mediated agents, including nanoparticle, conjugates and antibody-drug conjugates, have created revolutionary drug delivery systems in cancer over the past two decades. While these agents provide several advantages, such as greater duration of exposure and solubility, compared with their small-molecule counterparts, there is substantial variability in delivery of these agents to tissues and especially tumors. This review provides an overview of tumor microenvironment factors that affect the pharmacokinetics and pharmacodynamics of carrier-mediated agents observed in preclinical models and patients.
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Affiliation(s)
- Andrew T Lucas
- Division of Pharmacotherapy & Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Carolina Institute for Nanomedicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lauren Sl Price
- Division of Pharmacotherapy & Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Carolina Institute for Nanomedicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Allison Schorzman
- Division of Pharmacotherapy & Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - William C Zamboni
- Division of Pharmacotherapy & Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Carolina Institute for Nanomedicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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8
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Kandemir EG, Mayadagli A, Turken O, Yaylaci M, Ozturk A. Pre-treatment Haemoglobin Concentration is a Prognostic Factor in Patients with Early-stage Breast Cancer. J Int Med Res 2016; 33:319-28. [PMID: 15938593 DOI: 10.1177/147323000503300307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We investigated the prevalence of anaemia (haemoglobin concentration < 12 g/dl) in 336 women with early-stage breast cancer and its association with other known prognostic factors. The median follow-up period was 60.5 months (range 9-123 months). Seventy-nine women (23.5%) had a low pre-treatment haemoglobin concentration, but anaemia was not correlated with age, tumour size, nodal status, histological grade or hormone receptor status. Univariate analysis revealed that disease-free survival and overall survival were shorter in patients with anaemia at the time of diagnosis than in patients with normal haemoglobin concentrations. Anaemia remained a significant prognostic factor for disease-free survival and overall survival in the multivariate analysis (relative risk, 1.884 and 1.785, respectively). These results suggest that pre-treatment haemoglobin concentration is an independent prognostic factor in patients with early-stage breast cancer.
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Affiliation(s)
- E G Kandemir
- Medical Oncology Department, GATA Haydarpasa Training Hospital, Kadikoy, Istanbul, Turkey.
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9
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Abstract
In the last decades, several studies demonstrated that the tumor microenvironment is a critical determinant not only of tumor progression and metastasis, but also of resistance to therapy. Exosomes are small membrane vesicles of endocytic origin, which contain mRNAs, DNA fragments, and proteins, and are released by many different cell types, including cancer cells. Mounting evidence has shown that cancer-derived exosomes contribute to the recruitment and reprogramming of constituents associated with the tumor microenvironment. Understanding how exosomes and the tumor microenvironment impact drug resistance will allow novel and better strategies to overcome drug resistance and treat cancer. Here, we describe a technique for exosome purification from cell culture, and fresh and frozen plasma, and further analysis by electron microscopy, NanoSight microscope, and Western blot.
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Affiliation(s)
- Maria do Rosário André
- Champalimaud Foundation, Lisbon, Portugal.
- Department of Genetics, Oncology and Human Toxicology, NOVA Medical School/Faculty of Medical Sciences, NOVA University, Lisbon, Portugal.
| | - Ana Pedro
- Champalimaud Foundation, Lisbon, Portugal
- Department of Genetics, Oncology and Human Toxicology, NOVA Medical School/Faculty of Medical Sciences, NOVA University, Lisbon, Portugal
| | - David Lyden
- Champalimaud Foundation, Lisbon, Portugal
- Department of Genetics, Oncology and Human Toxicology, NOVA Medical School/Faculty of Medical Sciences, NOVA University, Lisbon, Portugal
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10
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Womeldorff M, Gillespie D, Jensen RL. Hypoxia-inducible factor-1 and associated upstream and downstream proteins in the pathophysiology and management of glioblastoma. Neurosurg Focus 2015; 37:E8. [PMID: 25581937 DOI: 10.3171/2014.9.focus14496] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with an exceptionally poor patient outcome despite aggressive therapy including surgery, radiation, and chemotherapy. This aggressive phenotype may be associated with intratumoral hypoxia, which probably plays a key role in GBM tumor growth, development, and angiogenesis. A key regulator of cellular response to hypoxia is the protein hypoxia-inducible factor–1 (HIF-1). An examination of upstream hypoxic and nonhypoxic regulation of HIF-1 as well as a review of the downstream HIF-1– regulated proteins may provide further insight into the role of this transcription factor in GBM pathophysiology. Recent insights into upstream regulators that intimately interact with HIF-1 could provide potential therapeutic targets for treatment of this tumor. The same is potentially true for HIF-1–mediated pathways of glycolysis-, angiogenesis-, and invasion-promoting proteins. Thus, an understanding of the relationship between HIF-1, its upstream protein regulators, and its downstream transcribed genes in GBM pathogenesis could provide future treatment options for the care of patients with these tumors.
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11
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Scanlon SE, Glazer PM. Multifaceted control of DNA repair pathways by the hypoxic tumor microenvironment. DNA Repair (Amst) 2015; 32:180-189. [PMID: 25956861 DOI: 10.1016/j.dnarep.2015.04.030] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hypoxia, as a pervasive feature in the microenvironment of solid tumors, plays a significant role in cancer progression, metastasis, and ultimately clinical outcome. One key cellular consequence of hypoxic stress is the regulation of DNA repair pathways, which contributes to the genomic instability and mutator phenotype observed in human cancers. Tumor hypoxia can vary in severity and duration, ranging from acute fluctuating hypoxia arising from temporary blockages in the immature microvasculature, to chronic moderate hypoxia due to sparse vasculature, to complete anoxia at distances more than 150 μM from the nearest blood vessel. Paralleling the intra-tumor heterogeneity of hypoxia, the effects of hypoxia on DNA repair occur through diverse mechanisms. Acutely, hypoxia activates DNA damage signaling pathways, primarily via post-translational modifications. On a longer timescale, hypoxia leads to transcriptional and/or translational downregulation of most DNA repair pathways including DNA double-strand break repair, mismatch repair, and nucleotide excision repair. Furthermore, extended hypoxia can lead to long-term persistent silencing of certain DNA repair genes, including BRCA1 and MLH1, revealing a mechanism by which tumor suppressor genes can be inactivated. The discoveries of the hypoxic modulation of DNA repair pathways have highlighted many potential ways to target susceptibilities of hypoxic cancer cells. In this review, we will discuss the multifaceted hypoxic control of DNA repair at the transcriptional, post-transcriptional, and epigenetic levels, and we will offer perspective on the future of its clinical implications.
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Affiliation(s)
- Susan E Scanlon
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA; Department of Experimental Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Peter M Glazer
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.
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12
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Verduzco D, Lloyd M, Xu L, Ibrahim-Hashim A, Balagurunathan Y, Gatenby RA, Gillies RJ. Intermittent hypoxia selects for genotypes and phenotypes that increase survival, invasion, and therapy resistance. PLoS One 2015; 10:e0120958. [PMID: 25811878 PMCID: PMC4374837 DOI: 10.1371/journal.pone.0120958] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 02/08/2015] [Indexed: 01/06/2023] Open
Abstract
Hypoxia in tumors correlates with greater risk of metastases, increased invasiveness, and resistance to systemic and radiation therapy. The evolutionary dynamics that links specific adaptations to hypoxia with these observed tumor properties have not been well investigated. While some tumor populations may experience fixed hypoxia, cyclical and stochastic transitions from normoxia to hypoxia are commonly observed in vivo. Although some phenotypic adaptations to this cyclic hypoxia are likely reversible, we hypothesize that some adaptations may become fixed through mutations promoted by hypoxia-induced genomic instability. Here we seek to identify genetic alterations and corresponding stable phenotypes that emerge following cyclic hypoxia. Although these changes may originate as adaptations to this specific environmental stress, their fixation in the tumor genome may result in their observation in tumors from regions of normoxia, a condition known as pseudohypoxia. We exposed several epithelial cell lines to 50 cycles of hypoxia-normoxia, followed by culture in normoxia over a period of several months. Molecular analyses demonstrated permanent changes in expression of several oncogenes and tumor-suppressors, including p53, E-cadherin, and Hif-1α. These changes were associated with increased resistance to multiple cytotoxins, increased survival in hypoxia and increased anchorage-independent growth. These results suggest cycles of hypoxia encountered in early cancers can select for specific and stable genotypic and phenotypic properties that persist even in normoxic conditions, which may promote tumor progression and resistance to therapy.
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Affiliation(s)
- Daniel Verduzco
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America
| | - Mark Lloyd
- Analytic Microscopy Core, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America
| | - Liping Xu
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America
| | - Arig Ibrahim-Hashim
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America
| | - Yoganand Balagurunathan
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America
| | - Robert A. Gatenby
- Department of Radiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America
| | - Robert J. Gillies
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America
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13
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Environmental stress induces trinucleotide repeat mutagenesis in human cells. Proc Natl Acad Sci U S A 2015; 112:3764-9. [PMID: 25775519 DOI: 10.1073/pnas.1421917112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The dynamic mutability of microsatellite repeats is implicated in the modification of gene function and disease phenotype. Studies of the enhanced instability of long trinucleotide repeats (TNRs)-the cause of multiple human diseases-have revealed a remarkable complexity of mutagenic mechanisms. Here, we show that cold, heat, hypoxic, and oxidative stresses induce mutagenesis of a long CAG repeat tract in human cells. We show that stress-response factors mediate the stress-induced mutagenesis (SIM) of CAG repeats. We show further that SIM of CAG repeats does not involve mismatch repair, nucleotide excision repair, or transcription, processes that are known to promote TNR mutagenesis in other pathways of instability. Instead, we find that these stresses stimulate DNA rereplication, increasing the proportion of cells with >4 C-value (C) DNA content. Knockdown of the replication origin-licensing factor CDT1 eliminates both stress-induced rereplication and CAG repeat mutagenesis. In addition, direct induction of rereplication in the absence of stress also increases the proportion of cells with >4C DNA content and promotes repeat mutagenesis. Thus, environmental stress triggers a unique pathway for TNR mutagenesis that likely is mediated by DNA rereplication. This pathway may impact normal cells as they encounter stresses in their environment or during development or abnormal cells as they evolve metastatic potential.
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14
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Citrate concentrations increase with hypoperfusion in pediatric diffuse intrinsic pontine glioma. J Neurooncol 2015; 122:383-9. [PMID: 25670389 DOI: 10.1007/s11060-015-1726-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 02/01/2015] [Indexed: 12/22/2022]
Abstract
Citrate, a tricarboxylic acid cycle intermediate, is present in high concentrations in pediatric diffuse intrinsic pontine gliomas (DIPG). Since citrate increases during hypoxia in animal studies, we hypothesized that it accumulates in DIPG when hypoperfused. Relative tumor blood volumes (rTBV) were determined, using dynamic susceptibility contrast-enhanced magnetic resonance imaging, in twelve children [median age 8.2 (range 3.2-14.5) years] with DIPG and compared to citrate concentrations measured with in vivo proton magnetic resonance spectroscopy ((1)H MRS). Tissue perfusion and metabolite concentration were assessed at initial presentation and over the clinical course, yielding 36 and 46 perfusion and MR spectroscopy datasets, respectively. At presentation, DIPG blood volume was 60 ± 27 % of that measured for normal cerebellum. Citrate, which is not detectable in normal brain tissue, was present in DIPG at concentrations of 3.81 ± 1.44 mmol/kg tissue. Over the course of the disease and treatment, rTBV increased and citrate decreased (both p < 0.05) with an inverse correlation (p = 0.028). Citrate accumulation is associated with tissue hypoperfusion in DIPG.
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15
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Dutta B, Yan R, Lim SK, Tam JP, Sze SK. Quantitative profiling of chromatome dynamics reveals a novel role for HP1BP3 in hypoxia-induced oncogenesis. Mol Cell Proteomics 2014; 13:3236-49. [PMID: 25100860 DOI: 10.1074/mcp.m114.038232] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In contrast to the intensely studied genetic and epigenetic changes that induce host cell transformation to initiate tumor development, those that promote the malignant progression of cancer remain poorly defined. As emerging evidence suggests that the hypoxic tumor microenvironment could re-model the chromatin-associated proteome (chromatome) to induce epigenetic changes and alter gene expression in cancer cells, we hypothesized that hypoxia-driven evolution of the chromatome promotes malignant changes and the development of therapy resistance in tumor cells. To test this hypothesis, we isolated chromatins from tumor cells treated with varying conditions of normoxia, hypoxia, and re-oxygenation and then partially digested them with DNase I and analyzed them for changes in euchromatin- and heterochromatin-associated proteins using an iTRAQ-based quantitative proteomic approach. We identified a total of 1446 proteins with a high level of confidence, including 819 proteins that were observed to change their chromatin association topology under hypoxic conditions. These hypoxia-sensitive proteins included key mediators of chromatin organization, transcriptional regulation, and DNA repair. Furthermore, our proteomic and functional experiments revealed a novel role for the chromatin organizer protein HP1BP3 in mediating chromatin condensation during hypoxia, leading to increased tumor cell viability, radio-resistance, chemo-resistance, and self-renewal. Taken together, our findings indicate that HP1BP3 is a key mediator of tumor progression and cancer cell acquisition of therapy-resistant traits, and thus might represent a novel therapeutic target in a range of human malignancies.
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Affiliation(s)
- Bamaprasad Dutta
- From the ‡School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr., Singapore 637551
| | - Ren Yan
- From the ‡School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr., Singapore 637551
| | - Sai Kiang Lim
- §Institute of Medical Biology, A*STAR, 8A Biomedical Grove, Immunos, Singapore 138648
| | - James P Tam
- From the ‡School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr., Singapore 637551
| | - Siu Kwan Sze
- From the ‡School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr., Singapore 637551;
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16
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Scanlon SE, Glazer PM. Hypoxic stress facilitates acute activation and chronic downregulation of fanconi anemia proteins. Mol Cancer Res 2014; 12:1016-28. [PMID: 24688021 DOI: 10.1158/1541-7786.mcr-13-0628] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
UNLABELLED Hypoxia induces genomic instability through replication stress and dysregulation of vital DNA repair pathways. The Fanconi anemia (FA) proteins, FANCD2 and FANCI, are key members of a DNA repair pathway that responds to replicative stress, suggesting that they undergo regulation by hypoxic conditions. Here acute hypoxic stress activates the FA pathway via ubiquitination of FANCD2 and FANCI in an ATR-dependent manner. In addition, the presence of an intact FA pathway is required for preventing hypoxia-induced DNA damage measurable by the comet assay, limiting the accumulation of γH2AX (a marker of DNA damage or stalled replication), and protecting cells from hypoxia-induced apoptosis. Furthermore, prolonged hypoxia induces transcriptional repression of FANCD2 in a manner analogous to the hypoxic downregulation of BRCA1 and RAD51. Thus, hypoxia-induced FA pathway activation plays a key role in maintaining genome integrity and cell survival, while FA protein downregulation with prolonged hypoxia contributes to genomic instability. IMPLICATIONS This work highlights the critical role of the FA pathway in response to hypoxic stress and identifies the pathway as a therapeutic target under hypoxic conditions.
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Affiliation(s)
- Susan E Scanlon
- Authors' Affiliations: Departments of Therapeutic Radiology, Experimental Pathology, and
| | - Peter M Glazer
- Authors' Affiliations: Departments of Therapeutic Radiology, Genetics, Yale University School of Medicine, New Haven, Connecticut
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Raz S, Sheban D, Gonen N, Stark M, Berman B, Assaraf YG. Severe hypoxia induces complete antifolate resistance in carcinoma cells due to cell cycle arrest. Cell Death Dis 2014; 5:e1067. [PMID: 24556682 PMCID: PMC3944254 DOI: 10.1038/cddis.2014.39] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/14/2014] [Indexed: 02/08/2023]
Abstract
Antifolates have a crucial role in the treatment of various cancers by inhibiting key enzymes in purine and thymidylate biosynthesis. However, the frequent emergence of inherent and acquired antifolate resistance in solid tumors calls for the development of novel therapeutic strategies to overcome this chemoresistance. The core of solid tumors is highly hypoxic due to poor blood circulation, and this hypoxia is considered to be a major contributor to drug resistance. However, the cytotoxic activity of antifolates under hypoxia is poorly characterized. Here we show that under severe hypoxia, gene expression of ubiquitously expressed key enzymes and transporters in folate metabolism and nucleoside homeostasis is downregulated. We further demonstrate that carcinoma cells become completely refractory, even at sub-millimolar concentrations, to all hydrophilic and lipophilic antifolates tested. Moreover, tumor cells retained sensitivity to the proteasome inhibitor bortezomib and the topoisomerase II inhibitor doxorubicin, which are independent of cell cycle. We provide evidence that this antifolate resistance, associated with repression of folate metabolism, is a result of the inability of antifolates to induce DNA damage under hypoxia, and is attributable to a hypoxia-induced cell cycle arrest, rather than a general anti-apoptotic mechanism. Our findings suggest that solid tumors harboring a hypoxic core of cell cycle-arrested cells may display antifolate resistance while retaining sensitivity to the chemotherapeutics bortezomib and doxorubicin. This study bears important implications for the molecular basis underlying antifolate resistance under hypoxia and its rational overcoming in solid tumors.
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Affiliation(s)
- S Raz
- Department of Biology, The Fred Wyszkowski Cancer Research Laboratory, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - D Sheban
- Department of Biology, The Fred Wyszkowski Cancer Research Laboratory, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - N Gonen
- Department of Biology, The Fred Wyszkowski Cancer Research Laboratory, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - M Stark
- Department of Biology, The Fred Wyszkowski Cancer Research Laboratory, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - B Berman
- Department of Biology, The Fred Wyszkowski Cancer Research Laboratory, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Y G Assaraf
- Department of Biology, The Fred Wyszkowski Cancer Research Laboratory, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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Gillies RJ, Flowers CI, Drukteinis JS, Gatenby RA. A unifying theory of carcinogenesis, and why targeted therapy doesn't work. Eur J Radiol 2013; 81 Suppl 1:S48-50. [PMID: 23083599 DOI: 10.1016/s0720-048x(12)70018-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Robert J Gillies
- Department of Radiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33602, USA.
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Luoto KR, Kumareswaran R, Bristow RG. Tumor hypoxia as a driving force in genetic instability. Genome Integr 2013; 4:5. [PMID: 24152759 PMCID: PMC4016142 DOI: 10.1186/2041-9414-4-5] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 10/16/2013] [Indexed: 12/26/2022] Open
Abstract
Sub-regions of hypoxia exist within all tumors and the presence of intratumoral hypoxia has an adverse impact on patient prognosis. Tumor hypoxia can increase metastatic capacity and lead to resistance to chemotherapy and radiotherapy. Hypoxia also leads to altered transcription and translation of a number of DNA damage response and repair genes. This can lead to inhibition of recombination-mediated repair of DNA double-strand breaks. Hypoxia can also increase the rate of mutation. Therefore, tumor cell adaptation to the hypoxic microenvironment can drive genetic instability and malignant progression. In this review, we focus on hypoxia-mediated genetic instability in the context of aberrant DNA damage signaling and DNA repair. Additionally, we discuss potential therapeutic approaches to specifically target repair-deficient hypoxic tumor cells.
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Affiliation(s)
- Kaisa R Luoto
- Ontario Cancer Institute, Radiation Medicine Program, Princess Margaret Cancer Centre (University Health Network), Toronto, ON, Canada
| | - Ramya Kumareswaran
- Ontario Cancer Institute, Radiation Medicine Program, Princess Margaret Cancer Centre (University Health Network), Toronto, ON, Canada.,Departments of Medical Biophysics and Radiation Oncology, University of Toronto, Radiation Medicine Program, Princess Margaret Cancer Centre (University Health Network), 610 University Avenue, Toronto, ON M5G2M9, Canada
| | - Robert G Bristow
- Ontario Cancer Institute, Radiation Medicine Program, Princess Margaret Cancer Centre (University Health Network), Toronto, ON, Canada.,Departments of Medical Biophysics and Radiation Oncology, University of Toronto, Radiation Medicine Program, Princess Margaret Cancer Centre (University Health Network), 610 University Avenue, Toronto, ON M5G2M9, Canada
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Abstract
Hypoxia plays a central role in tumour development, angiogenesis, growth and resistance to treatment. Owing to constant developments in medical imaging technology, significant advances have been made towards in vitro and in vivo imaging of hypoxia in a variety of tumours, including gliomas of the central nervous system. The aim of this article is to review the literature on imaging approaches currently available for measuring hypoxia in human gliomas and provide an insight into recent advances and future directions in this field. After a brief overview of hypoxia and its importance in gliomas, several methods of measuring hypoxia will be presented. These range from invasive monitoring by Eppendorf polarographic O(2) microelectrodes, positron electron tomography (PET) tracers based on 2-nitroimidazole compounds [(18)F-labelled fluoro-misonidazole ((18)F-MISO) or 1-(2-[((18))F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole (FRP-170)], (64)Cu-ATSM Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) or (99m)Tc- and (68)Ga-labelled metronidazole (MN) agents to advanced MRI methods, such as blood oxygenation level dependent (BOLD) MRI, oxygen-enhanced MRI, diffusion-weighted MRI (DWI-MRI), dynamic contrast-enhanced MRI (DCE-MRI) and (1)H-magnetic resonance spectroscopy.
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Affiliation(s)
- I Mendichovszky
- Wolfson Molecular Imaging Centre, University of Manchester, Withington, Manchester, UK
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21
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Mattern J, Volm M. Role of oxygenation and vascularization in drug resistance. Cytotechnology 2012; 27:249-56. [PMID: 19002796 DOI: 10.1023/a:1008033326059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Oxygenation status and tumor vascularization seem to be important factors in determining therapeutic effectiveness and patient prognosis. An abundance of data on tumor oxygenation and vascularization is available and it clearly shows that most human solid tumors are heterogeneously oxygenated and vascularized. They contain hypoxic regions. Such regions and areas of reduced vascularization can affect the response to a variety of drugs. Direct measurements of pO(2) and the vascular density in various types of tumors have, upon correlation of the data to therapeutic outcome, shown that low pO(2) values and low vascular density are associated with a decreased response to therapy. Therefore, oxygenation status and the extent of tumor vascularization may well be important factors contributing to the difficulty of successful therapy in certain types of tumors.
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Gillies RJ, Verduzco D, Gatenby RA. Evolutionary dynamics of carcinogenesis and why targeted therapy does not work. Nat Rev Cancer 2012; 12:487-93. [PMID: 22695393 PMCID: PMC4122506 DOI: 10.1038/nrc3298] [Citation(s) in RCA: 455] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
All malignant cancers, whether inherited or sporadic, are fundamentally governed by Darwinian dynamics. The process of carcinogenesis requires genetic instability and highly selective local microenvironments, the combination of which promotes somatic evolution. These microenvironmental forces, specifically hypoxia, acidosis and reactive oxygen species, are not only highly selective, but are also able to induce genetic instability. As a result, malignant cancers are dynamically evolving clades of cells living in distinct microhabitats that almost certainly ensure the emergence of therapy-resistant populations. Cytotoxic cancer therapies also impose intense evolutionary selection pressures on the surviving cells and thus increase the evolutionary rate. Importantly, the principles of Darwinian dynamics also embody fundamental principles that can illuminate strategies for the successful management of cancer.
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Affiliation(s)
- Robert J Gillies
- Department of Cancer Physiology and Biophysics, H. Lee Moffitt Cancer Center and Research Institute, Tampa FL 33602, USA.
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Pal A, Srivastava T, Sharma MK, Mehndiratta M, Das P, Sinha S, Chattopadhyay P. Aberrant methylation and associated transcriptional mobilization of Alu elements contributes to genomic instability in hypoxia. J Cell Mol Med 2011; 14:2646-54. [PMID: 19508390 PMCID: PMC4373486 DOI: 10.1111/j.1582-4934.2009.00792.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hypoxia is an integral part of tumorigenesis and contributes extensively to the neoplastic phenotype including drug resistance and genomic instability. It has also been reported that hypoxia results in global demethylation. Because a majority of the cytosine-phosphate-guanine (CpG) islands are found within the repeat elements of DNA, and are usually methylated under normoxic conditions, we suggested that retrotransposable Alu or short interspersed nuclear elements (SINEs) which show altered methylation and associated changes of gene expression during hypoxia, could be associated with genomic instability. U87MG glioblastoma cells were cultured in 0.1% O2 for 6 weeks and compared with cells cultured in 21% O2 for the same duration. Real-time PCR analysis showed a significant increase in SINE and reverse transcriptase coding long interspersed nuclear element (LINE) transcripts during hypoxia. Sequencing of bisulphite treated DNA as well as the Combined Bisulfite Restriction Analysis (COBRA) assay showed that the SINE loci studied underwent significant hypomethylation though there was patchy hypermethylation at a few sites. The inter-alu PCR profile of DNA from cells cultured under 6-week hypoxia, its 4-week revert back to normoxia and 6-week normoxia showed several changes in the band pattern indicating increased alu mediated genomic alteration. Our results show that aberrant methylation leading to increased transcription of SINE and reverse transcriptase associated LINE elements could lead to increased genomic instability in hypoxia. This might be a cause of genetic heterogeneity in tumours especially in variegated hypoxic environment and lead to a development of foci of more aggressive tumour cells.
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Affiliation(s)
- Arnab Pal
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
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Affiliation(s)
- Minoru Koi
- Division of Gastroenterology, Department of Internal Medicine, Sammons Cancer Center, Baylor Research Institute, Dallas, Texas 75246, USA.
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Abstract
Genetic instability is one of the hallmarks of cancer cells. As tumors grow, they progressively acquire mutations that ultimately allow them to invade normal tissues and metastasize to distant sites. This increased propensity for mutation also leads to cancers that are resistant to therapeutic intervention. Recent evidence has shown that the tumor microenvironment plays a major role in the etiology of this phenomenon; as tumors are exposed to repeated cycles of hypoxia and reoxygenation, they downregulate a number of DNA repair pathways, thus leading to genetic instability. Understanding the mechanisms involved in this process may provide insights into the development of novel treatment strategies.
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Affiliation(s)
- Thomas J Klein
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520-8040, USA
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Albertini RJ, Carson ML, Kirman CR, Gargas ML. 1,3-Butadiene: II. Genotoxicity profile. Crit Rev Toxicol 2010; 40 Suppl 1:12-73. [PMID: 20868267 DOI: 10.3109/10408444.2010.507182] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1,3-Butadiene’s (BD’s) major electrophilic metabolites 1,2-epoxy-3-butene (EB), 1,2-dihydroxy-3,4-epoxybutane (EBD), and 1,2,3,4-diepoxybutane (DEB) are responsible for both its mutagenicity and carcinogenicity. EB, EBD, and DEB are DNA reactive, forming a variety of adducts. All three metabolites are genotoxic in vitro and in vivo, with relative mutagenic potencies of DEB >> EB > EBD. DEB also effectively produces gene deletions and chromosome aberrations. BD’s greater mutagenicity and carcinogenicity in mice over rats as well as its failure to induce chromosome-level mutations in vivo in rats appear to be due to greater production of DEB in mice. Concentrations of EB and DEB in vivo in humans are even lower than in rats. Although most studies of BD-exposed humans have failed to find increases in gene mutations, one group has reported positive findings. Reasons for these discordant results are examined. BD-related chromosome aberrations have never been demonstrated in humans except for the possible production of micronuclei in lymphocytes of workers exposed to extremely high levels of BD in the workplace. The relative potencies of the BD metabolites, their relative abundance in the different species, and the kinds of mutations they can induce are major considerations in BD’s overall genotoxicity profile.
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Affiliation(s)
- Richard J Albertini
- Pathology Department, College of Medicine, University of Vermont, Burlington, Vermont, USA
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Hypoxia and the metabolic phenotype of prostate cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1433-43. [DOI: 10.1016/j.bbabio.2009.06.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/21/2009] [Accepted: 06/07/2009] [Indexed: 12/27/2022]
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Yoo YG, Hayashi M, Christensen J, Huang LE. An essential role of the HIF-1alpha-c-Myc axis in malignant progression. Ann N Y Acad Sci 2009; 1177:198-204. [PMID: 19845622 DOI: 10.1111/j.1749-6632.2009.05043.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cancer is a disease of genomic aberration. The hypoxic microenvironment is believed to promote tumor progression via the induction of genetic instability. To understand how hypoxia drives tumor progression, we have shown recently that the hypoxia-inducible transcription factor, HIF-1alpha, is critical for transcriptional repression of DNA repair genes by a noncanonical mode of action referred to as the "HIF-1alpha-c-Myc axis." HIF-1alpha action via the HIF-1alpha-c-Myc axis is independent of its DNA-binding and transactivation domains; instead it requires the PAS-B domain to displace the transcription activator c-Myc from the target gene promoter for gene repression. Owing to the functional compromise on DNA repair, tumor cells with activated HIF-1alpha-c-Myc axis display persistent DNA damage, genetic alterations, and malignant progression. However, apoptosis-proficient cells are resistant to such changes. These findings argue that the hypoxic microenvironment plays a critical role in driving genetic alterations especially in apoptosis-deficient cells for malignant progression.
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Affiliation(s)
- Young-Gun Yoo
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, UT 84132, USA
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High resolution ultra high field magnetic resonance imaging of glioma microvascularity and hypoxia using ultra-small particles of iron oxide. Invest Radiol 2009; 44:375-83. [PMID: 19448552 DOI: 10.1097/rli.0b013e3181a8afea] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES This study assessed whether ultra-small particles of iron oxide (USPIO) intravascular contrast agent could enhance visualization of tumor microvascularity in F98 glioma bearing rats by means of ultra high field (UHF) high-resolution gradient echo (GRE) magnetic resonance imaging (MRI). In an effort to explain differences in visualization of microvascularity before and after USPIO administration, hypoxia and vessel diameters were assessed on corresponding histopathologic sections. MATERIALS AND METHODS F98 glioma cells were implanted stereotactically into the brains of syngeneic Fischer rats. Based on clinical criteria, rats were imaged 1 to 2 days before their death with and without USPIO contrast on an 8 Tesla MRI. To identify hypoxic regions of the brain tumor by immunohistochemical staining, a subset of animals also received a nitroimidazole-based hypoxia marker, EF5, before euthanasia. These sections then were compared with noncontrast enhanced MR images. The relative caliber of tumor microvasculature, compared with that of normal brain, was analyzed in a third group of animals. RESULTS After USPIO administration, UHF high-resolution GRE MRI consistently predicted increased microvascular density relative to normal gray matter when correlated with histopathology. The in-plane visibility of glioma microvascularity in 22 rats increased by an average of 115% and signal intensity within the tumor decreased by 13% relative to normal brain. Tumor microvascularity identified on noncontrast MR images matched hypoxic regions identified by immunohistochemical staining with a sensitivity of 83% and specificity of 89%. UHF GRE MRI was able to resolve microvessels less than 20 micro in diameter, although differences in tumor vessel size did not consistently account for differences in visualization of microvascularity. CONCLUSIONS USPIO administration significantly enhanced visualization of tumor microvascularity on gradient echo 8 T MRI and significantly improved visualization of tumor microvascularity. Microvascularity identified on precontrast images is suspected to be partly associated with hypoxia.
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Brain tumor hypoxia: tumorigenesis, angiogenesis, imaging, pseudoprogression, and as a therapeutic target. J Neurooncol 2009; 92:317-35. [PMID: 19357959 DOI: 10.1007/s11060-009-9827-2] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 02/23/2009] [Indexed: 02/07/2023]
Abstract
Hypoxia is implicated in many aspects of tumor development, angiogenesis, and growth in many different tumors. Brain tumors, particularly the highly aggressive glioblastoma multiforme (GBM) with its necrotic tissues, are likely affected similarly by hypoxia, although this involvement has not been closely studied. Invasion, apoptosis, chemoresistance, resistance to antiangiogenic therapy, and radiation resistance may all have hypoxic mechanisms. The extent of the influence of hypoxia in these processes makes it an attractive therapeutic target for GBM. Because of their relationship to glioma and meningioma growth and angiogenesis, hypoxia-regulated molecules, including hypoxia inducible factor-1, carbonic anhydrase IX, glucose transporter 1, and vascular endothelial growth factor, may be suitable subjects for therapies. Furthermore, other novel hypoxia-regulated molecules that may play a role in GBM may provide further options. Emerging imaging techniques may allow for improved determination of hypoxia in human brain tumors to better focus therapeutic treatments; however, tumor pseudoprogression, which may be prompted by hypoxia, poses further challenges. An understanding of the role of hypoxia in tumor development and growth is important for physicians involved in the care of patients with brain tumors.
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Vaupel P. Physiological Mechanisms of Treatment Resistance. THE IMPACT OF TUMOR BIOLOGY ON CANCER TREATMENT AND MULTIDISCIPLINARY STRATEGIES 2009. [DOI: 10.1007/978-3-540-74386-6_15] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Kuo MT. Redox regulation of multidrug resistance in cancer chemotherapy: molecular mechanisms and therapeutic opportunities. Antioxid Redox Signal 2009; 11:99-133. [PMID: 18699730 PMCID: PMC2577715 DOI: 10.1089/ars.2008.2095] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The development of multidrug resistance to cancer chemotherapy is a major obstacle to the effective treatment of human malignancies. It has been established that membrane proteins, notably multidrug resistance (MDR), multidrug resistance protein (MRP), and breast cancer resistance protein (BCRP) of the ATP binding cassette (ABC) transporter family encoding efflux pumps, play important roles in the development of multidrug resistance. Overexpression of these transporters has been observed frequently in many types of human malignancies and correlated with poor responses to chemotherapeutic agents. Evidence has accumulated showing that redox signals are activated in response to drug treatments that affect the expression and activity of these transporters by multiple mechanisms, including (a) conformational changes in the transporters, (b) regulation of the biosynthesis cofactors required for the transporter's function, (c) regulation of the expression of transporters at transcriptional, posttranscriptional, and epigenetic levels, and (d) amplification of the copy number of genes encoding these transporters. This review describes various specific factors and their relevant signaling pathways that are involved in the regulation. Finally, the roles of redox signaling in the maintenance and evolution of cancer stem cells and their implications in the development of intrinsic and acquired multidrug resistance in cancer chemotherapy are discussed.
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Affiliation(s)
- Macus Tien Kuo
- Department of Molecular Pathology (Unit 951), The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
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Abstract
Regional chemotherapy was developed in the 1950s and continues to play an integral part in the development of newer therapies for advanced solid malignancies. Regional therapies have evolved in complexity but are still based on the pharmacokinetics of drug delivery to solid malignancies. Newer techniques demonstrate that the combination of regional therapies, hyperthermia, and surgery is essential in promoting improved patient outcomes.
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Rebuzzini P, Neri T, Zuccotti M, Redi CA, Garagna S. Chromosome number variation in three mouse embryonic stem cell lines during culture. Cytotechnology 2008; 58:17-23. [PMID: 19002773 DOI: 10.1007/s10616-008-9164-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 09/12/2008] [Indexed: 12/30/2022] Open
Abstract
Although mouse embryonic stem cell lines (mESCs) have been established since 1981, systematic studies about chromosomal changes during culture are lacking. In this study, we report the results of a cytogenetic analysis performed on three mESC lines (named UPV02, UPV06 and UPV08) cultured for a period of 3 months. At time intervals, the variation of the chromosome number together with the expression of markers of the undifferentiated status, i.e., OCT-4, SSEA-1, FOM-1 and alkaline phosphatase activity, were determined. The three mESC lines showed a progressive loss of euploid metaphases during the 3 months period of culture. Chromosome abnormalities were accumulated at the latest passages analysed. Metacentric chromosomes were the most frequent chromosome abnormality observed throughout the period of culture. Interestingly, in coincidence with, or few passages after, the drop of euploidy, the alkaline phosphatase activity was partially or totally lost, whereas the OCT-4, SSEA-1 and FOM-1 stem markers were always positive throughout the period of culture. Our results remark the necessity to perform the karyotype analysis during culture in order to develop new culture conditions to maintain the correct chromosome complement in long-term culture of mESC lines.
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Affiliation(s)
- Paola Rebuzzini
- Dipartimento di Biologia Animale, Laboratorio di Biologia dello Sviluppo, Universita' degli Studi di Pavia, Piazza Botta 9, 27100, Pavia, Italy
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Kitajima Y, Ide T, Ohtsuka T, Miyazaki K. Induction of hepatocyte growth factor activator gene expression under hypoxia activates the hepatocyte growth factor/c-Met system via hypoxia inducible factor-1 in pancreatic cancer. Cancer Sci 2008; 99:1341-7. [PMID: 18422749 DOI: 10.1111/j.1349-7006.2008.00828.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Hepatocyte growth facor activator (HGFA) is a serine protease that converts hepatocyte growth factor (HGF) into its active form. Our previous study demonstrated that tumor-stromal interaction under hypoxia augments the aggressive invasive features of pancreatic cancer line PK8 through activated HGF/c-Met signaling. The present study investigated whether or not hypoxia increases HGFA expression in PK8 cells and promotes the processing of HGF, and leads to c-Met activation. Moreover, HGFA promoter assays were performed to define whether hypoxia inducible factor-1 alpha (HIF-1alpha) directly activates the HGFA promoter in a hypoxia-dependent fashion. As a result, hypoxia induced the HGFA mRNA and protein expression in PK8 and the elevation under hypoxia was inhibited by the transfection of HIF-1alpha siRNA, thus indicating HIF-1alpha-dependent induction of HGFA. The transfection of siRNA against HGFA to PK8 cells suppressed the conversion to the active HGF, which is secreted from fibroblast MRC5. Furthermore, the phosphorylation of c-Met and cancer invasion of PK8 cells were decreased by the transfection of HGFA siRNA under hypoxia. Using the luciferase reporter system, HIF-1alpha was shown to transactivate the HGFA promoter under hypoxia. These experiments demonstrated for the first time that HGFA is a novel HIF-1 target gene. Under hypoxia, HGFA might be overexpressed and secreted from pancreatic cancer cells, which contributes to accelerate processing of HGF from fibroblast, resulting in the activation of the c-Met pathway. HGF/HGFA/c-Met recruited between cancer-stromal fibroblasts is activated under hypoxic conditions and therefore might play a central role in the aggressive invasion of pancreatic cancer.
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Affiliation(s)
- Yoshihiko Kitajima
- Department of Surgery, Saga University Faculty of Medicine, Saga, B49-8501 Japan
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Macapinlac HA. Clinical applications of positron emission tomography/computed tomography treatment planning. Semin Nucl Med 2008; 38:137-40. [PMID: 18243849 DOI: 10.1053/j.semnuclmed.2007.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Positron emission tomography/computed tomography (PET/CT) has provided an incremental dimension to the management of cancer patients by allowing the incorporation of important molecular images in radiotherapy treatment planning, ie, direct evaluation of tumor metabolism, cell proliferation, apoptosis, hypoxia, and angiogenesis. The CT component allows 4D imaging techniques, allowing improvements in the accuracy of treatment delivery by compensating for tumor/normal organ motion, improving PET quantification, and correcting PET and CT image misregistration. The combination of PET and CT in a single imaging system to obtain a fused anatomical and functional image data is now emerging as a promising tool in radiotherapy departments for improved delineation of tumor volumes and optimization of treatment plans. PET has the potential to improve radiotherapy planning by minimizing unnecessary irradiation of normal tissues and by reducing the risk of geographic miss. PET influences treatment planning in a high proportion of cases and therefore radiotherapy dose escalation without PET may be futile. This article examines the increasing role of hybrid PET/CT imaging techniques in process of improving treatment planning in oncology with emphasis on non small cell lung cancer.
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Affiliation(s)
- Homer A Macapinlac
- Department of Nuclear Medicine, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Reshmi SC, Huang X, Schoppy DW, Black RC, Saunders WS, Smith DI, Gollin SM. Relationship between FRA11F and 11q13 gene amplification in oral cancer. Genes Chromosomes Cancer 2007; 46:143-54. [PMID: 17099871 DOI: 10.1002/gcc.20394] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Common fragile sites (CFS) are nonstaining gaps or breaks in chromosomes that are expressed under conditions inducing replicative stress. CFS have been suggested to play a role in epithelial cancers by their association with loss of heterozygosity, loss of gene expression, and/or gene amplification in the form of homogeneously staining regions (hsrs). In oral squamous-cell carcinomas (OSCC), amplification of chromosomal band 11q13 occurs in the form of an hsr. We suggested previously that CFS flanking 11q13 may be susceptible to breakage induced by tobacco or other carcinogens and/or human papillomavirus, promoting formation of the 11q13 amplicon. Examination of OSCC cell lines with 11q13 amplification using fluorescence in situ hybridization showed loss of FRA11F sequences, whereas cell lines without 11q13 amplification displayed an intact FRA11F site. Cell lines with more complex 11q rearrangements expressed FRA11F in the form of an inverted duplication, characteristic of breakage-fusion-bridge cycles. Our findings suggest that gene amplification involving chromosomal band 11q13 in OSCC may be initiated by breakage at FRA11F.
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Affiliation(s)
- Shalini C Reshmi
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261, USA
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Trédan O, Galmarini CM, Patel K, Tannock IF. Drug Resistance and the Solid Tumor Microenvironment. J Natl Cancer Inst 2007; 99:1441-54. [PMID: 17895480 DOI: 10.1093/jnci/djm135] [Citation(s) in RCA: 1496] [Impact Index Per Article: 88.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Resistance of human tumors to anticancer drugs is most often ascribed to gene mutations, gene amplification, or epigenetic changes that influence the uptake, metabolism, or export of drugs from single cells. Another important yet little-appreciated cause of anticancer drug resistance is the limited ability of drugs to penetrate tumor tissue and to reach all of the tumor cells in a potentially lethal concentration. To reach all viable cells in the tumor, anticancer drugs must be delivered efficiently through the tumor vasculature, cross the vessel wall, and traverse the tumor tissue. In addition, heterogeneity within the tumor microenvironment leads to marked gradients in the rate of cell proliferation and to regions of hypoxia and acidity, all of which can influence the sensitivity of the tumor cells to drug treatment. In this review, we describe how the tumor microenvironment may be involved in the resistance of solid tumors to chemotherapy and discuss potential strategies to improve the effectiveness of drug treatment by modifying factors relating to the tumor microenvironment.
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Affiliation(s)
- Olivier Trédan
- Division of Applied Molecular Oncology and Department of Medical Oncology and Hematology, Princess Margaret Hospital, 610 University Ave, Toronto, ON M5G 2M9, Canada
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Wouters A, Pauwels B, Lardon F, Vermorken JB. Review: implications of in vitro research on the effect of radiotherapy and chemotherapy under hypoxic conditions. Oncologist 2007; 12:690-712. [PMID: 17602059 DOI: 10.1634/theoncologist.12-6-690] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
As it is now well established that human solid tumors frequently contain a substantial fraction of cells that are hypoxic, more and more in vitro research is focusing on the impact of hypoxia on the outcome of radiotherapy and chemotherapy. Indeed, the efficacy of irradiation and many cytotoxic drugs relies on an adequate oxygen supply. Consequently, hypoxic regions in solid tumors often contain viable cells that are intrinsically more resistant to treatment with radiotherapy or chemotherapy. Moreover, efforts have been made to exploit hypoxia as a potential difference between malignant and normal tissues.Nowadays, a body of evidence indicates that oxygen deficiency clearly influences some major intracellular pathways such as those involved in cell proliferation, cell cycle progression, apoptosis, cell adhesion, and others. Obviously, when investigating the effects of radiotherapy or chemotherapy or both combined under hypoxic conditions, it is essential to consider the influences of hypoxia itself on the cell. In this review, we first focus on the effects of hypoxia per se on some critical biological pathways. Next, we sketch an overview of preclinical and clinical research on radiotherapy, chemotherapy, and chemoradiation under hypoxic conditions.
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Affiliation(s)
- An Wouters
- Laboratory of Cancer Research and Clinical Oncology, Department of Medical Oncology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
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Ide T, Kitajima Y, Miyoshi A, Ohtsuka T, Mitsuno M, Ohtaka K, Miyazaki K. The hypoxic environment in tumor-stromal cells accelerates pancreatic cancer progression via the activation of paracrine hepatocyte growth factor/c-Met signaling. Ann Surg Oncol 2007; 14:2600-7. [PMID: 17534684 DOI: 10.1245/s10434-007-9435-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 04/05/2007] [Indexed: 12/26/2022]
Abstract
BACKGROUND Pancreatic cancer is one of the representative solid tumors, in which the hypoxic microenvironment plays a crucial role in malignant progression. We previously demonstrated that tumor-stromal interaction under hypoxia enhances the invasiveness of pancreatic cancer cells through hepatocyte growth factor (HGF)/c-Met signaling. METHODS We investigated the immunohistochemical expression of hypoxia inducible factor-1alpha (HIF-1alpha) c-Met, and HGF in both cancer and stromal cells using 41 pancreatic cancer tissue specimens, and tried to identify any correlations with the clinical features and survival. RESULTS Positive staining for HIF-1alpha was observed in both pancreatic cancer and the surrounding stromal cells in more than 30% of the cases, and it significantly correlated with lymph node metastasis (P < .05). A significant correlation was observed between the expression of HIF-1alpha and HGF in stromal cells (P < .05). In addition, the c-Met expression in cancer cells was found to significantly correlate with the HGF expression in not only cancer but also stromal cells. The disease-free survival rates of the patients with HIF-1alpha in cancer, stromal, c-Met in cancer, and an HGF expression in stromal cells was significantly worse than those without such expressions (P < .05). CONCLUSIONS These data suggest that the HGF/c-Met signaling via HIF-1alpha ?may therefore negatively affect the prognosis in patients with pancreatic cancer, and targeting tumor stroma under hypoxia might thus be potentially useful as a novel therapy for this cancer.
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Affiliation(s)
- Takao Ide
- Department of Surgery, Saga University Faculty of Medicine, Saga, Japan
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Abstract
Positron emission tomography (PTE) is a technique that allows imaging of the temporal and spatial distribution of positron-emitting radionuclides. The purpose of this article is to outline the current clinical use for PET imaging in the brain and other radiopharmaceutical used for assessing various physiologic parameters pertaining to tumor metabolism.
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Affiliation(s)
- Homer A Macapinlac
- Department of Nuclear Medicine, Division of Diagnostic Imaging, University of Texas, MD Anderson Cancer Center, 1515 Holcombe Boulevard, Box 83, Houston, TX 77030, USA.
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Abstract
Positron emission tomography (PET) is a technique that allows imaging of the temporal and spatial distribution of positron-emitting radionuclides. The purpose of this article is to outline the current clinical use for PET imaging in the brain and other radiopharmaceuticals used for assessing various physiologic parameters pertaining to tumor metabolism.
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Affiliation(s)
- Homer A Macapinlac
- Department of Nuclear Medicine, Division of Diagnostic Imaging, University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Box 83, Houston, TX 77030, USA.
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Huang LE, Bindra RS, Glazer PM, Harris AL. Hypoxia-induced genetic instability--a calculated mechanism underlying tumor progression. J Mol Med (Berl) 2006; 85:139-48. [PMID: 17180667 DOI: 10.1007/s00109-006-0133-6] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 10/18/2006] [Accepted: 10/20/2006] [Indexed: 12/13/2022]
Abstract
The cause of human cancers is imputed to the genetic alterations at nucleotide and chromosomal levels of ill-fated cells. It has long been recognized that genetic instability-the hallmark of human cancers-is responsible for the cellular changes that confer progressive transformation on cancerous cells. How cancer cells acquire genetic instability, however, is unclear. We propose that tumor development is a result of expansion and progression-two complementary aspects that collaborate with the tumor microenvironment-hypoxia in particular, on genetic alterations through the induction of genetic instability. In this article, we review the recent literature regarding how hypoxia functionally impairs various DNA repair pathways resulting in genetic instability and discuss the biomedical implications in cancer biology and treatment.
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Affiliation(s)
- L Eric Huang
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
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Jensen RL. Hypoxia in the tumorigenesis of gliomas and as a potential target for therapeutic measures. Neurosurg Focus 2006; 20:E24. [PMID: 16709030 DOI: 10.3171/foc.2006.20.4.16] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
✓ In this article, the author provides a brief description of the role of hypoxia in the tumorigenesis of gliomas and suggests potential ways of exploiting this role to design treatment modalities. Tumor hypoxia predicts the likelihood of metastases, tumor recurrence, resistance to chemotherapy and radiation therapy, invasive potential, and decreased patient survival for many human malignancies. Various methods of measurement of tumor hypoxia are discussed, including direct measurement and imaging methods.
The role of hypoxia-responsive molecules, especially hypoxia-inducible factor-1 (HIF-1), in glioma tumorigenesis is explored. Treatment modalities regulated by hypoxia are proposed and some potential strategies reviewed. The progression of a low-grade astrocytoma to a glioblastoma multiforme may be mediated by hypoxia-induced phenotypic changes and subsequent clonal selection of cells that overexpress hypoxia-responsive molecules, such as HIF-1. In this model, intratumoral hypoxia causes genetic changes that produce a microenvironment that selects for cells of a more aggressive phenotype.
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Affiliation(s)
- Randy L Jensen
- Department of Neurosurgery, University of Utah, Salt Lake City, Utah 84132, USA.
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Koshikawa N, Maejima C, Miyazaki K, Nakagawara A, Takenaga K. Hypoxia selects for high-metastatic Lewis lung carcinoma cells overexpressing Mcl-1 and exhibiting reduced apoptotic potential in solid tumors. Oncogene 2006; 25:917-28. [PMID: 16247470 DOI: 10.1038/sj.onc.1209128] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Low oxygen tension (hypoxia) is a common feature of solid tumors and stimulates the expressions of a variety of genes including those related to angiogenesis, apoptosis and endoplasmic reticulum (ER) stress response. Here we show a close correlation between metastatic potential and the resistance to hypoxia- and ER stress-induced apoptosis among the cell lines with differing metastatic potential derived from Lewis lung carcinoma. An apoptosis-specific expression profiling and immunoblot analyses revealed that the expression of antiapoptotic Mcl-1 increased as the resistance to apoptosis increased. Downregulation of the Mcl-1 expression in the high-metastatic cells by Mcl-1 small interfering RNA increased the sensitivity to hypoxia-induced apoptosis and decreased the metastatic ability. The hypoxia-induced apoptosis was not associated with p53 accumulation, although at present it is not possible to conclude that apoptosis-induced apoptosis is p53-independent. There was no correlation between the expression levels of ER stress-response proteins GADD153, GRP78 and ORP150 and the resistance to hypoxia or ER stresses. In vitro, small numbers of the high-metastatic cells overtook the low-metastatic cells after exposure to several rounds of hypoxia and reoxygenation. In solid tumors initially established from equal mixtures, the proportion of the high-metastatic cells to low-metastatic cells was significantly higher in hypoxic areas. Moreover, the high-metastatic cells were overtaking the low-metastatic cells in some of the tumors. Thus, tumor hypoxia and ER stress may provide a physiological selective pressure for the expansion of the high-metastatic cells overexpressing Mcl-1 and exhibiting reduced apoptotic potential in solid tumors.
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Affiliation(s)
- N Koshikawa
- Division of Chemotherapy, Chiba Cancer Center Research Institute, Chuoh-ku, Chiba, Japan
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Koshikawa N, Takenaga K. Hypoxia-regulated expression of attenuated diphtheria toxin A fused with hypoxia-inducible factor-1alpha oxygen-dependent degradation domain preferentially induces apoptosis of hypoxic cells in solid tumor. Cancer Res 2006; 65:11622-30. [PMID: 16357173 DOI: 10.1158/0008-5472.can-05-0111] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tumor cells in hypoxic areas of solid tumors are resistant to conventional chemotherapy and radiotherapy and thus are obstacles of cancer therapy. We report here the feasibility of applying hypoxia-regulated expression of diphtheria toxin A (DT-A) for killing hypoxic tumor cells. The expression vector was constructed to express DT-A fused with hypoxia-inducible factor-1alpha (HIF-1alpha) oxygen-dependent degradation (ODD) domain under the control of vascular endothelial growth factor gene promoter and contain erythropoietin mRNA-binding protein (ERBP)-binding sequence downstream of the DT-A/ODD sequence. In vitro ubiquitination assay showed that DT-A/ODD, but not DT-A, was ubiquitinated as efficient as HIF-1alpha under normoxic conditions in a von Hippel-Lindau- and oxygen-dependent manner. DT-A/ODD exhibited a comparable translation inhibitory activity to DT-A. ERBP-binding sequence was effective in stabilizing mRNA under hypoxic conditions in various cell types. Transfection of the vector expressing DT-A/ODD into high-metastatic Lewis lung carcinoma (3LL) A11 cells resulted in induction of apoptosis independently of hypoxia, probably due to its extreme toxicity. However, transfection of the vector expressing attenuated DT-A(W153F)/ODD or DT-A(H21A)/ODD resulted in a hypoxia-dependent induction of apoptosis. Liposomal gene transfer of the vector encoding DT-A(W153F)/ODD induced apoptosis in hypoxic, but not in normoxic, areas of solid tumors established by A11 variant cells with higher resistance to hypoxia-induced apoptosis and inhibited the growth of hypoxic tumors established by 3LL-P29 cells. These results suggest that hypoxia-regulated expression of attenuated DT-A(W153F)/ODD fusion protein is potentially of use for killing hypoxic tumor cells with minimizing the damage to normoxic normal tissues.
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MESH Headings
- Animals
- Apoptosis
- Carcinoma, Lewis Lung/metabolism
- Carcinoma, Lewis Lung/pathology
- Carcinoma, Lewis Lung/secondary
- Cell Hypoxia
- Diphtheria Toxin/genetics
- Diphtheria Toxin/metabolism
- Erythropoietin/genetics
- Female
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Kidney Neoplasms/metabolism
- Kidney Neoplasms/pathology
- Liposomes
- Liver Neoplasms, Experimental/metabolism
- Liver Neoplasms, Experimental/pathology
- Lung Neoplasms/metabolism
- Lung Neoplasms/pathology
- Lung Neoplasms/secondary
- Mice
- Mice, Inbred C57BL
- Oxygen/metabolism
- Peptide Fragments/genetics
- Peptide Fragments/metabolism
- Promoter Regions, Genetic/genetics
- Protein Biosynthesis
- Protein Structure, Tertiary
- RNA, Messenger
- RNA-Binding Proteins/genetics
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Transfection
- Tumor Cells, Cultured
- Ubiquitin/metabolism
- Vascular Endothelial Growth Factor A/genetics
- Von Hippel-Lindau Tumor Suppressor Protein/genetics
- Von Hippel-Lindau Tumor Suppressor Protein/metabolism
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Affiliation(s)
- Nobuko Koshikawa
- Division of Chemotherapy, Chiba Cancer Center Research Institute, Japan
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Hara S, Nakashiro KI, Klosek SK, Ishikawa T, Shintani S, Hamakawa H. Hypoxia enhances c-Met/HGF receptor expression and signaling by activating HIF-1alpha in human salivary gland cancer cells. Oral Oncol 2006; 42:593-8. [PMID: 16469527 DOI: 10.1016/j.oraloncology.2005.10.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 10/20/2005] [Indexed: 11/28/2022]
Abstract
Hypoxia increases the invasive and metastatic potential of tumor cells. Increased expression of c-Met/hepatocyte growth factor (HGF)-receptor protein in response to hypoxia in thyroid papillary carcinomas is hypoxia-inducible factor-1 (HIF-1) dependent. Both HGF and c-Met are expressed in human salivary gland cancers. In the current study, we tested whether c-Met expression was regulated by hypoxia and HIF-1alpha using two human salivary gland cancer cell lines: GFP-ACC2 and GFP-ACCM. Hypoxia enhanced the expression of HIF-1alpha in both cell lines, whereas c-Met was markedly induced only in the GFP-ACCM cells, which have metastatic potential. In the latter, hypoxia also promoted HGF-induced invasiveness. Synthetic small-interfering RNA specific for HIF-1alpha inhibited HIF-1alpha expression in the GFP-ACCM cells, and also suppressed the increase in c-Met expression and HGF-induced invasiveness under hypoxic conditions. These results suggest that hypoxia activates the HGF/c-Met system via HIF-1alpha in human salivary gland cancers and might be involved in their metastasis.
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Affiliation(s)
- Shingo Hara
- Department of Oral and Maxillofacial Surgery, Ehime University School of Medicine, 454 Shitsukawa, Toon, Ehime 791-0295, Japan
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Yao K, Gietema JA, Shida S, Selvakumaran M, Fonrose X, Haas NB, Testa J, O'Dwyer PJ. In vitro hypoxia-conditioned colon cancer cell lines derived from HCT116 and HT29 exhibit altered apoptosis susceptibility and a more angiogenic profile in vivo. Br J Cancer 2006; 93:1356-63. [PMID: 16333244 PMCID: PMC2361533 DOI: 10.1038/sj.bjc.6602864] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypoxia is an important selective force in the clonal evolution of tumours. Through HIF-1 and other transcription factors combined with tumour-specific genetic alterations, hypoxia is a dominant factor in the angiogenic phenotype. Cellular adaptation to hypoxia is an important requirement of tumour progression independent of angiogenesis. The adaptive changes, insofar as they alter hypoxia-induced apoptosis, are likely to determine responsiveness to antiangiogenic strategies. To investigate this adaptation of tumour cells to hypoxia, we recreated in vitro the in vivo situation of chronic intermittent exposure to low-oxygen levels. The colon carcinoma cell lines HT29 and HCT116 were subjected to 40 episodes of sublethal hypoxia (4 h) three times a week. The resulting two hypoxia-conditioned cell lines have been maintained in culture for more than 2 years. In both cell lines changes in doubling times occurred: in HT29 an increase, and in HCT116 a decrease. Cell survival in response to hypoxia and to DNA damage differed strikingly in the two cell lines. The HT29 hypoxia-conditioned cells were more resistant than the parental line to a 24 h hypoxic challenge, while those from HCT116 surprisingly were more sensitive. Sensitivity to cisplatin in vitro was also significantly different for the hypoxia-conditioned compared with the parental lines, suggesting a change in pathways leading to apoptosis following DNA damage signaling. The growth of both conditioned cell lines in vivo as xenografts in immunodeficient (SCID) mice was more rapid than their parental lines, and was accompanied in each by evidence of enhanced vascular proliferation as a consequence of the hypoxia-conditioning. Thus the changes in apoptotic susceptibility were independent of altered angiogenesis. The derivation of these lines provides a model for events within hypoxic regions of colon cancers, and for the acquisition of resistance and sensitivity characteristics that may have therapeutic implications for the use of antiangiogenesis drugs.
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Affiliation(s)
- K Yao
- University of Pennsylvania Cancer Center, Philadelphia, 51 N. 39st street, MAB Suite 103, PA 19104, USA
| | - J A Gietema
- Groningen University Hospital, Groningen The Netherlands
| | - S Shida
- University of Pennsylvania Cancer Center, Philadelphia, 51 N. 39st street, MAB Suite 103, PA 19104, USA
| | - M Selvakumaran
- University of Pennsylvania Cancer Center, Philadelphia, 51 N. 39st street, MAB Suite 103, PA 19104, USA
| | - X Fonrose
- University of Pennsylvania Cancer Center, Philadelphia, 51 N. 39st street, MAB Suite 103, PA 19104, USA
| | - N B Haas
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - J Testa
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - P J O'Dwyer
- University of Pennsylvania Cancer Center, Philadelphia, 51 N. 39st street, MAB Suite 103, PA 19104, USA
- University of Pennsylvania Cancer Center, Philadelphia, 51 N. 39st street, MAB Suite 103, PA 19104, USA. E-mail:
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Banáth JP, Sinnott L, Larrivée B, MacPhail SH, Olive PL. Growth of V79 Cells as Xenograft Tumors Promotes Multicellular Resistance but does not Increase Spontaneous or Radiation-Induced Mutant Frequency. Radiat Res 2005; 164:733-44. [PMID: 16296879 DOI: 10.1667/3474.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A Chinese hamster V79 xenograft model was developed to determine whether cells subjected to a hypoxic tumor microenvironment would be more likely to undergo mutation at the HPRT locus. V79-171b cells stably transfected with VEGF and EGFP were grown subcutaneously in immunodeficient NOD/ SCID mice. V79-VE tumors were characterized for host cell infiltration, doubling time, hypoxic fraction, vascular perfusion, and response to ionizing radiation. When irradiated in vitro, the mutant frequency for a given surviving fraction did not differ for cells grown in vivo or in vitro. Similar results were obtained using HCT116 human colorectal carcinoma cells grown as xenografts. However, V79-VE cells grown as xenografts were significantly more resistant to killing than monolayers. The background mutant frequency and the radiation-induced mutant frequency did not differ for tumor cells close to or distant from blood vessels. Similarly, tumor cells from well-perfused regions showed the same rate of strand break rejoining and the same rate of loss of phosphorylated histone H2AX as cells sorted from poorly perfused regions. Therefore, deleterious effects of the tumor microenvironment on DNA repair efficiency or mutation induction could not be demonstrated in these tumors. Rather, development of multicellular resistance in V79-VE tumors acted to reduce mutant frequency for a given dose of radiation.
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Affiliation(s)
- J P Banáth
- British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada, V5Z 1L3
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50
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Koshiji M, To KKW, Hammer S, Kumamoto K, Harris AL, Modrich P, Huang LE. HIF-1alpha induces genetic instability by transcriptionally downregulating MutSalpha expression. Mol Cell 2005; 17:793-803. [PMID: 15780936 DOI: 10.1016/j.molcel.2005.02.015] [Citation(s) in RCA: 258] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Revised: 01/14/2005] [Accepted: 02/14/2005] [Indexed: 12/27/2022]
Abstract
Hypoxia promotes genetic instability by undefined mechanisms. The transcription factor HIF-1alpha is crucial for the cellular response to hypoxia and is frequently overexpressed in human cancers, resulting in the activation of genes essential for cell survival. Here, we demonstrate that HIF-1alpha is responsible for genetic instability at the nucleotide level by inhibiting MSH2 and MSH6, thereby decreasing levels of the MSH2-MSH6 complex, MutSalpha, which recognizes base mismatches. HIF-1alpha displaces the transcriptional activator Myc from Sp1 binding to repress MutSalpha expression in a p53-dependent manner; Sp1 serves as a molecular switch by recruiting HIF-1alpha to the gene promoter under hypoxia. Furthermore, in human sporadic colon cancers, HIF-1alpha overexpression is statistically associated with the loss of MSH2 expression, especially when p53 is immunochemically undetectable. These findings indicate that the regulation of DNA repair is an integral part of the hypoxic response, providing molecular insights into the mechanisms underlying hypoxia-induced genetic instability.
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Affiliation(s)
- Minori Koshiji
- Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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