701
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Dong GL, Xing LN, Liu XB, Liu W, Jin Q, Zhang SY. Properties of radiation-induced apoptosis and cell cycle changes in liver cancer cell lines. Shijie Huaren Xiaohua Zazhi 2006; 14:2834-2837. [DOI: 10.11569/wcjd.v14.i29.2834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To analyze the properties of radiation-induced apoptosis and cell cycle changes in liver cancer cell lines.
METHODS: Liver cancer cell lines HepG2 and SMMC-7721 were included in this study, and normal liver cell line HL-7702, pulmonary small cell carcinoma cell line HCI-H460 and lung adenocarcinoma cell line A549 were used as controls. After routine culture for 48 h, all the cells were irradiated under 4Gy X-radiation. The cell cycle and apoptosis were detected by flow cytometry (FCM) before and 6, 12, 24, 36, 48 h after irradiation.
RESULTS: After irradiation, cell apoptosis started from the 6th h and reached to the peak at 12 h in HepG2 cells (ΔApoHepG2= 45.16%, t = 8.864, P < 0.0025), while at 24 h in SMMC-7721 cells (ΔApo7721 = 24.94%). In comparison with SMMC-7721 cells, HepG2 cells had an earlier and higher apoptosis peak. The cell cycle and apoptosis were generally in the same situation in HCI-H460 and A549 cells as those in SMMC-7721 and HepG2 cells. The pre-S-phase cell apoptosis was found in both kinds of liver cancer cells. Significant blockage of G2/M phase occurred 12 h after irradiation.
CONCLUSION: After 4Gy X-radiation, premitotic apoptosis occurs both in HepG2 and SMMC-7721 cells. Furthermore, X-radiation may induce G2/M-phase cell injuries and deaths in HepG2 cells.
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702
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Cordes N. Integrin-mediated cell–matrix interactions for prosurvival and antiapoptotic signaling after genotoxic injury. Cancer Lett 2006; 242:11-9. [PMID: 16448744 DOI: 10.1016/j.canlet.2005.12.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 11/22/2005] [Accepted: 12/04/2005] [Indexed: 01/10/2023]
Abstract
Interactions of cells with their microenvironment modify the cellular sensitivity of normal and tumor cells for radiation- and drug-induced genotoxic injury. The preexistent or acquired cellular resistance against such agents aggravates anticancer therapies and, therefore, complicates the recovery of patients. Recently, integrin-mediated adhesion was shown to improve cell survival of both normal and cancer cells following DNA damage. Here, I will discuss the role of integrins and integrin-mediated signaling cascades in the survival or death response upon genotoxic stress. Detailed knowledge of the responsible molecular processes might provide implications for putative therapies targeting integrins or integrin-associated molecules to achieve an optimization of anticancer treatments.
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Affiliation(s)
- Nils Cordes
- OncoRay-Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, University of Technology Dresden,Fetscherstrasse 74/PF 86, 01307 Dresden, Germany.
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703
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Zhao W, Kridel S, Thorburn A, Kooshki M, Little J, Hebbar S, Robbins M. Fatty acid synthase: a novel target for antiglioma therapy. Br J Cancer 2006; 95:869-78. [PMID: 16969344 PMCID: PMC2360524 DOI: 10.1038/sj.bjc.6603350] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
High levels of fatty acid synthase (FAS) expression have been observed in several cancers, including breast, prostate, colon and lung carcinoma, compared with their respective normal tissue. We present data that show high levels of FAS protein in human and rat glioma cell lines and human glioma tissue samples, as compared to normal rat astrocytes and normal human brain. Incubating glioma cells with the FAS inhibitor cerulenin decreased endogenous fatty acid synthesis by approximately 50%. Cell cycle analysis demonstrated a time- and dose-dependent increase in S-phase cell arrest following cerulenin treatment for 24 h. Further, treatment with cerulenin resulted in time- and dose-dependent decreases in glioma cell viability, as well as reduced clonogenic survival. Increased apoptotic cell death and PARP cleavage were observed in U251 and SNB-19 cells treated with cerulenin, which was independent of the death receptor pathway. Overexpressing Bcl-2 inhibited cerulenin-mediated cell death. In contrast, primary rat astrocytes appeared unaffected. Finally, RNAi-mediated knockdown of FAS leading to reduced FAS enzymatic activity was associated with decreased glioma cell viability. These findings suggest that FAS might be a novel target for antiglioma therapy.
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Affiliation(s)
- W Zhao
- Department of Radiation Oncology, Brain Tumor Center of Excellence, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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704
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Albert JM, Kim KW, Cao C, Lu B. Targeting the Akt/mammalian target of rapamycin pathway for radiosensitization of breast cancer. Mol Cancer Ther 2006; 5:1183-9. [PMID: 16731750 DOI: 10.1158/1535-7163.mct-05-0400] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is known to be activated by radiation. The mammalian target of rapamycin (mTOR) is downstream of Akt, and we investigated the effects of radiation on Akt/mTOR signaling in breast cancer cell models. RAD001 (everolimus), a potent derivative of the mTOR inhibitor rapamycin, was used to study the effects of mTOR inhibition, as the role of mTOR inhibition in enhancing radiation remains unexplored. RAD001 decreased clonogenic cell survival in both breast cancer cell lines MDA-MB-231 and MCF-7, although the effect is greater in MDA-MB-231 cells. Irradiation induced Akt and mTOR signaling, and this signaling is attenuated by RAD001. The radiation-induced signaling activation is mediated by PI3K because inhibition of PI3K with LY294002 inhibited the increase in downstream mTOR signaling. Additionally, caspase-dependent apoptosis is an important mechanism of cell death when RAD001 is combined with 3 Gy radiation, as shown by induction of caspase-3 cleavage. An increase in G(2)-M cell cycle arrest was seen in the combination treatment group when compared with controls, suggesting that cell cycle arrest may have been a contributing factor in the increased radiosensitization seen in this study. We conclude that RAD001 attenuates radiation-induced prosurvival Akt/mTOR signaling and enhances the cytotoxic effects of radiation in breast cancer cell models, showing promise as a method of radiosensitization of breast cancer.
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Affiliation(s)
- Jeffrey M Albert
- Department of Radiation Oncology, Vanderbilt University, B-902 The Vanderbilt Clinic, 1301 22nd Avenue South, Nashville, TN 37232-5671, USA
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705
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Chen MF, Lin CT, Chen WC, Yang CT, Chen CC, Liao SK, Liu JM, Lu CH, Lee KD. The sensitivity of human mesenchymal stem cells to ionizing radiation. Int J Radiat Oncol Biol Phys 2006; 66:244-53. [PMID: 16839703 DOI: 10.1016/j.ijrobp.2006.03.062] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 03/17/2006] [Accepted: 03/17/2006] [Indexed: 12/20/2022]
Abstract
PURPOSE Recent studies have shown that mesenchymal stem cells (MSCs) obtained from bone marrow transplantation patients originate from the host. This clinical observation suggests that MSCs in their niches could be resistant to irradiation. However, the biologic responses of bone marrow MSCs to irradiation have rarely been described in the literature. METHODS AND MATERIALS In this study, human bone marrow-derived, clonally expanded MSCs were used to investigate their sensitivity to irradiation in vitro, and the cellular mechanisms that may facilitate resistance to irradiation. The human lung cancer cell line A549 and the breast cancer cell line HCC1937 were used as controls for radiosensitivity; the former line has been shown to be radioresistant and the latter radiosensitive. We then examined their in vitro biologic changes and sensitivities to radiation therapy. RESULTS Our results suggest that MSCs are characterized as resistant to irradiation. Several cellular mechanisms were demonstrated that may facilitate resistance to irradiation: ATM protein phosphorylation, activation of cell-cycle checkpoints, double-strand break repair by homologous recombination and nonhomologous end joining (NHEJ), and the antioxidant capacity for scavenging reactive oxygen species. CONCLUSIONS As demonstrated, MSCs possess a better antioxidant reactive oxygen species-scavenging capacity and active double-strand break repair to facilitate their radioresistance. These findings provide a better understanding of radiation-induced biologic responses in MSCs and may lead to the development of better strategies for stem cell treatment and cancer therapy.
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Affiliation(s)
- Miao-Fen Chen
- Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, Taiwan
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706
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Liliensiek SJ, Schell K, Howard E, Nealey P, Murphy CJ. Cell sorting but not serum starvation is effective for SV40 human corneal epithelial cell cycle synchronization. Exp Eye Res 2006; 83:61-8. [PMID: 16545370 PMCID: PMC3061619 DOI: 10.1016/j.exer.2005.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 10/28/2005] [Accepted: 11/01/2005] [Indexed: 11/22/2022]
Abstract
SV40 human corneal epithelial cell (HCEC) populations are readily used as a substitute for primary corneal epithelial cells that are difficult to maintain in vitro. To initiate cell-cycle experiments with the SV40-HCEC cells, two separate methods of cell synchronization were compared including serum starvation and sterile cell sorting. We hypothesized that SV40 cells are synchronized at higher efficiencies into each cell cycle phase (G1, S, G2M) when cell sorting is performed when compared to alternative methods of synchronization. SV40 cells were synchronized by deprivation of serum over 96 h or labeled with Höechst 33342 dye and sorted based on DNA content. Cells were synchronized using both methods and harvested at time points up to 72 h after release. To define more precisely the nature of sorted fractions, cells were pulsed with BrdU prior to sorting. SV40-HCEC cells exhibit a well-defined cell cycle profile. Serum deprivation up to 96 h was ineffective for cell synchronization of SV40-HCECs. In comparison, we achieved efficient synchronization of the SV40-HCECs with sterile cell sorting. SV40-HCEC cells gated into G1, S and G2M were synchronized up to 85% following the sort and maintained synchronization up to 24 h. Our findings indicate that serum starvation is not effective for synchronization of the SV40-HCEC cell line. We present a more effective approach, the use of cell sorting for cell synchronization of the SV40-HCEC cells.
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Affiliation(s)
- Sara J Liliensiek
- Department of Surgical Sciences, School of Veterinary Medicine, 2015 Linden Drive, University of Wisconsin, Madison, WI 53706, USA.
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707
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Turnbull C, Mirugaesu N, Eeles R. Radiotherapy and genetic predisposition to breast cancer. Clin Oncol (R Coll Radiol) 2006; 18:257-67. [PMID: 16605057 DOI: 10.1016/j.clon.2005.11.013] [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: 10/25/2022]
Abstract
Cancer genetics is becoming increasingly integrated into oncological care; particularly in breast cancer management. The recognition of monogenic breast cancer predisposition syndromes, such as BRCA, is critical as there is also a risk of other cancers in addition to a markedly elevated risk of contralateral breast cancer. In individuals with breast cancer due to some predisposition genes, radiation should be avoided, e.g. the ATM and TP53 genes, but there is still controversy as to whether radiation should be used in BRCA1/2 mutation carriers and more follow-up is needed. There are some radiation-sensitive genetic conditions where, if breast cancer occurs (as it may occur in any individual, not necessarily due to an increased risk associated with the condition), radiation should be avoided. These conditions are often associated with dysmorphic features. If such features are noticed then the advice of a geneticist should be sought urgently prior to giving radiation.
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Affiliation(s)
- C Turnbull
- Great Ormond Street Hospital, London and Royal Marsden NHS Foundation Trust, London, UK
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708
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Xavier S, Macdonald S, Roth J, Caunt M, Akalu A, Morais D, Buckley MT, Liebes L, Formenti SC, Brooks PC. The vitamin-like dietary supplement para-aminobenzoic acid enhances the antitumor activity of ionizing radiation. Int J Radiat Oncol Biol Phys 2006; 65:517-27. [PMID: 16690434 DOI: 10.1016/j.ijrobp.2006.01.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 01/04/2006] [Accepted: 01/06/2006] [Indexed: 11/17/2022]
Abstract
PURPOSE To determine whether para-aminobenzoic acid (PABA) alters the sensitivity of tumor cells to ionizing radiation in vitro and in vivo. METHODS AND MATERIALS Cellular proliferation was assessed by WST-1 assays. The effects of PABA and radiation on tumor growth were examined with chick embryo and murine models. Real-time reverse transcriptase-polymerase chain reaction and Western blotting were used to quantify p21CIP1 and CDC25A levels. RESULTS Para-aminobenzoic acid enhanced (by 50%) the growth inhibitory activity of radiation on B16F10 cells, whereas it had no effect on melanocytes. Para-aminobenzoic acid enhanced (50-80%) the antitumor activity of radiation on B16F10 and 4T1 tumors in vivo. The combination of PABA and radiation therapy increased tumor apoptosis. Treatment of tumor cells with PABA increased expression of CDC25A and decreased levels of p21CIP1. CONCLUSIONS Our findings suggest that PABA might represent a compound capable of enhancing the antitumor activity of ionizing radiation by a mechanism involving altered expression of proteins known to regulate cell cycle arrest.
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Affiliation(s)
- Sandhya Xavier
- Department of Radiation Oncology and Cell Biology, The NYU Cancer Institute, New York University School of Medicine, New York, NY 10016, USA
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709
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Guo HR, Chen CH, Ho SY, Ho YS, Chen RJ, Wang YJ. Staurosporine modulates radiosensitivity and radiation-induced apoptosis in U937 cells. Int J Radiat Biol 2006; 82:97-109. [PMID: 16546908 DOI: 10.1080/09553000600589149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE The present study aims at investigating the involvement of several genes in the cell cycle distribution and apoptosis in U937 cells, a cell line lacking functional p53 protein, after combined treatment with staurosporine and irradiation. MATERIALS AND METHODS Using a DNA fragmentation assay, flow cytometry and western blot analysis, the molecular basis for the effects of staurosporine in combination with the irradiation of leukemia cells was investigated. RESULTS Our results indicated that combined treatment led to an increased apoptotic cell death in U937 cells, which is correlated with the phosphorylation of the V-Jun sarcoma virus 17 oncogene homolog (c-JUN) NH(2)-terminal kinase protein (JNK), the activation of caspases, the increase in B cell leukemia/lymphoma 2 (Bcl-2) associated X protein (Bax), the decrease in Bcl xL protein (Bcl-XL) levels, the loss of mitochondria membrane potential and the release of cytochrome c. CONCLUSIONS Abrogation of the G2 checkpoint should be an effective strategy against p53-deficient leukemia cells to irradiation-induced cell killing.
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Affiliation(s)
- How-Ran Guo
- Department of Environmental and Occupational Health, National Cheng Kung University, Medical College, Tainan, Taiwan
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710
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An JH, Seong JS. Proteomics analysis of apoptosis-regulating proteins in tissues with different radiosensitivity. JOURNAL OF RADIATION RESEARCH 2006; 47:147-55. [PMID: 16819141 DOI: 10.1269/jrr.47.147] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The aim of this study was to identify of radiosusceptibility proteins in tissues with different radiosensitivity. C3H/HeJ mice were exposed to 10 Gy. The tissues were processed for proteins extraction and were analyzed by 2-dimensional electrophoresis. The proteins were identified by matrix-assisted laser desorption ionizing time-of-flight mass spectrometry and validated by immunohistochemical staining and Western blotting. The peaks of apoptosis levels were 35.3 +/- 1.7% and 0.6 +/- 0.2% in the spleen and the liver, respectively, after ionizing radiation. Analysis of liver tissue showed that the expression level of ROS related proteins such as cytochrome c, glutathione S transferase, NADH dehydrogenase and peroxiredoxin VI increased after radiation. The expression level of cytochrome c increased to 3-fold after ionizing radiation in both tissues. However in spleen tissue, the expression level of various kinds of apoptosis regulating proteins increased after radiation. These involved iodothyronine, CD 59A glycoprotein precursor, fas antigen and tumor necrosis factor -inducible protein TSG-6n precursor after radiation. The difference in the apoptosis index between the liver and spleen tissues is closely associated with the expression of various kinds of apoptosis-related proteins. The result suggests that the expression of apoptosis-related protein and redox proteins play important roles in this radiosusceptibility.
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Affiliation(s)
- Jeung Hee An
- Department of Radiation Oncology, Brain Korea 21 Project for Medical Science, Yonsei University Medical College, Seoul Korea.
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711
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Du Y, Yin F, Liu C, Hu S, Wang J, Xie H, Hong L, Fan D. Depression of MAD2 inhibits apoptosis of gastric cancer cells by upregulating Bcl-2 and interfering mitochondrion pathway. Biochem Biophys Res Commun 2006; 345:1092-8. [PMID: 16714000 DOI: 10.1016/j.bbrc.2006.04.172] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 04/27/2006] [Indexed: 01/22/2023]
Abstract
Mitotic arrest deficient 2 (MAD2) is an essential component of the mitotic spindle checkpoint pathway. It was previously shown to be associated with drug resistance of tumor cells. To further explore the roles of MAD2 in responses of gastric cancer cells to chemotherapy drugs, we constructed the siRNA vectors of MAD2 and transfected them into gastric cancer SGC7901 cells to inhibit expression of MAD2. MTT assay showed that the downregulation of MAD2 increased the resistance of SGC7901 cells to spindle inhibitors and DNA damaging agents. The apoptosis rates of gastric cancer cells transfected with MAD2-siRNA were 10.7% and 10%, respectively, after treated by 1.0microg/ml VCR and cisplatin. In contrast, the apoptosis rates of SGC7901 and SGC7901/psilencer3.1 induced by VCR were 43.2%, 38.7%; and that induced by cispaltin were 34.1%, 31.4%. The ratio of Bcl-2 to Bax was much higher in the MAD2-siRNA transfectants compared with the SGC7901/psilencer. In SGC7901/psilencer, cytochrome c and cleaved caspase 3 protein levels increased along with the exposure time increased. However, these protein levels of SGC7901/MAD2-siRNA had no changes during the drug treatment. These results indicate that down regulation of MAD2 could promote the drug resistance of gastric cancer cells and inhibit anticancer drugs induced-apoptosis by upregulating Bcl-2 and interfering the mitochondrion apoptosis pathway.
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Affiliation(s)
- Yulei Du
- State Key Laboratory of Cancer Biology, Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China
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712
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Vink SR, Lagerwerf S, Mesman E, Schellens JHM, Begg AC, van Blitterswijk WJ, Verheij M. Radiosensitization of squamous cell carcinoma by the alkylphospholipid perifosine in cell culture and xenografts. Clin Cancer Res 2006; 12:1615-22. [PMID: 16533789 DOI: 10.1158/1078-0432.ccr-05-2033] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Combined modality treatment has improved outcome in various solid tumors. Besides classic anticancer drugs, a new generation of biological response modifiers has emerged that increases the efficacy of radiation. Here, we have investigated whether perifosine, an orally applicable, membrane-targeted alkylphospholipid, enhances the antitumor effect of radiation in vitro and in vivo. EXPERIMENTAL DESIGN Several long-term and short-term in vitro assays (clonogenic survival, sulforhodamine B cytotoxicity, apoptosis, and cell cycle analysis) were used to assess the cytotoxic effect of perifosine in combination with radiation. In vivo, the response of human KB squamous cell carcinoma xenografts was measured after treatment with perifosine, irradiation, and the combination. Radiolabeled perifosine was used to determine drug disposition in tumor and normal tissues. At various intervals after treatment, tumor specimens were collected to document histopathologic changes. RESULTS In vitro, perifosine reduced clonogenic survival, enhanced apoptosis, and increased cell cycle arrest after radiation. In vivo, radiation and perifosine alone induced a dose-dependent tumor growth delay. When combining multiple perifosine administrations with single or split doses of radiation, complete and sustained tumor regression was observed. Histopathologic analysis of tumor specimens revealed a prominent apoptotic response after combined treatment with radiation and perifosine. Radiation-enhanced tumor response was observed at clinically relevant plasma perifosine concentrations and accumulating drug disposition of >100 microg/g in tumor tissue. CONCLUSIONS Perifosine enhances radiation-induced cytotoxicity, as evidenced by reduced clonogenic survival and increased apoptosis induction in vitro and by complete tumor regression in vivo. These data provide strong support for further development of this combination in clinical studies.
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Affiliation(s)
- Stefan R Vink
- Division of Experimental Therapy and Cellular Biochemistry, the Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands
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713
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Ishikawa KI, Koyama-Saegusa K, Otsuka Y, Ishikawa A, Kawai S, Yasuda K, Suga T, Michikawa Y, Suzuki M, Iwakawa M, Imai T. Gene expression profile changes correlating with radioresistance in human cell lines. Int J Radiat Oncol Biol Phys 2006; 65:234-45. [PMID: 16618578 DOI: 10.1016/j.ijrobp.2005.12.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 12/09/2005] [Accepted: 12/09/2005] [Indexed: 11/19/2022]
Abstract
PURPOSE To identify gene expression profiles specific to radioresistance of human cells. METHODS AND MATERIALS Global gene expression profiles of a total of 15 tumor and normal fibroblast cell lines were analyzed using DNA microarrays and statistical clustering methods. Initially, six of the cell lines were categorized into radioresistant (RG) or nonradioresistant (NRG) groups according to the radiation dose required to reduce their survival to 10% (D10). Genes for which expression was specific to each group at 1 or 3 h after irradiation were identified using statistical procedures including analysis of variance and a two-dimensional hierarchical clustering method. The remaining nine cell lines were subjected to the k-nearest neighbor pattern classification. RESULTS The nine test cell lines were successfully classified by their D10 value using 46 and 44 genes for which transcription levels had significantly changed at 1 and 3 h after irradiation, respectively. Of these genes, 25 showed altered expression at both time points in the NRG or RG, but independently were unable to classify the test cell lines. CONCLUSIONS Radioresistant cell lines analyzed in this study showed certain radiation-induced changes in gene expression profiles that are different from the profile changes of the more-sensitive cell lines.
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Affiliation(s)
- Ken-ichi Ishikawa
- RadGenomics Project, Frontier Research Center, National Institute of Radiological Sciences, Inage, Chiba, Japan
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714
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Yan T, Seo Y, Schupp JE, Zeng X, Desai AB, Kinsella TJ. Methoxyamine potentiates iododeoxyuridine-induced radiosensitization by altering cell cycle kinetics and enhancing senescence. Mol Cancer Ther 2006; 5:893-902. [PMID: 16648559 DOI: 10.1158/1535-7163.mct-05-0364] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We previously reported that methoxyamine (an inhibitor of base excision repair) potentiates iododeoxyuridine (IUdR)-induced radiosensitization in human tumor cells. In this study, we investigated the potential mechanisms of this enhanced cell death. Human colorectal carcinoma RKO cells were exposed to IUdR (3 micromol/L) and/or methoxyamine (3 mmol/L) for 48 hours before ionizing radiation (5 Gy). We found that IUdR/methoxyamine altered cell cycle kinetics and led to an increased G1 population but a decreased S population before ionizing radiation. Immediately following ionizing radiation (up to 6 hours), IUdR/methoxyamine-pretreated cells showed a stringent G1-S checkpoint but an insufficient G2-M checkpoint, whereas a prolonged G1 arrest, containing 2CG1 and 4CG1 cells, was found at later times up to 72 hours. Levels of cell cycle-specific markers [p21, p27, cyclin A, cyclin B1, and pcdc2(Y15)] and DNA damage signaling proteins [gammaH2AX, pChk1(S317), and pChk2(T68)] supported these altered cell cycle kinetics. Interestingly, we found that IUdR/methoxyamine pretreatment reduced ionizing radiation-induced apoptosis. Additionally, the extent of cell death through necrosis or autophagy seemed similar in all (IUdR +/- methoxyamine + ionizing radiation) treatment groups. However, a larger population of senescence-activated beta-galactosidase-positive cells was seen in IUdR/methoxyamine/ionizing radiation-treated cells, which was correlated with the increased activation of the senescence factors p53 and pRb. These data indicate that IUdR/methoxyamine pretreatment enhanced the effects of ionizing radiation by causing a prolonged G1 cell cycle arrest and by promoting stress-induced premature senescence. Thus, senescence, a novel ionizing radiation-induced tumor suppression pathway, may be effectively targeted by IUdR/methoxyamine pretreatment, resulting in an improved therapeutic gain for ionizing radiation.
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Affiliation(s)
- Tao Yan
- Department of Radiation Oncology, Case Comprehensive Cancer Center, University Hospitals of Cleveland, Cleveland, OH 44106-6068, USA
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715
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Raffoul JJ, Wang Y, Kucuk O, Forman JD, Sarkar FH, Hillman GG. Genistein inhibits radiation-induced activation of NF-kappaB in prostate cancer cells promoting apoptosis and G2/M cell cycle arrest. BMC Cancer 2006; 6:107. [PMID: 16640785 PMCID: PMC1464148 DOI: 10.1186/1471-2407-6-107] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 04/26/2006] [Indexed: 11/25/2022] Open
Abstract
Background New cancer therapeutic strategies must be investigated that enhance prostate cancer treatment while minimizing associated toxicities. We have previously shown that genistein, the major isoflavone found in soy, enhanced prostate cancer radiotherapy in vitro and in vivo. In this study, we investigated the cellular and molecular interaction between genistein and radiation using PC-3 human prostate cancer cells. Methods Tumor cell survival and progression was determined by clonogenic analysis, flow cytometry, EMSA analysis of NF-κB, and western blot analysis of cyclin B1, p21WAF1/Cip1, and cleaved PARP protein. Results Genistein combined with radiation caused greater inhibition in PC-3 colony formation compared to genistein or radiation alone. Treatment sequence of genistein followed by radiation and continuous exposure to genistein showed optimal effect. Cell cycle analysis demonstrated a significant dose- and time-dependent G2/M arrest induced by genistein and radiation that correlated with increased p21WAF1/Cip1 and decreased cyclin B1 expression. NF-κB activity was significantly decreased by genistein, yet increased by radiation. Radiation-induced activation of NF-κB activity was strongly inhibited by genistein pre-treatment. A significant and striking increase in cleaved PARP protein was measured following combined genistein and radiation treatment, indicating increased apoptosis. Conclusion A mechanism of increased cell death by genistein and radiation is proposed to occur via inhibition of NF-κB, leading to altered expression of regulatory cell cycle proteins such as cyclin B and/or p21WAF1/Cip1, thus promoting G2/M arrest and increased radiosensitivity. These findings support the important and novel strategy of combining genistein with radiation for the treatment of prostate cancer.
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Affiliation(s)
- Julian J Raffoul
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Yu Wang
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Omer Kucuk
- Division of Hematology/Oncology, Department of Internal Medicine, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
- Harper University Hospital, Detroit, MI, 48201, USA
| | - Jeffrey D Forman
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
- Harper University Hospital, Detroit, MI, 48201, USA
| | - Fazlul H Sarkar
- Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Gilda G Hillman
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
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716
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Misra A, Pellarin M, Hu L, Kunwar S, Perhouse M, Lamborn KR, Deen DF, Feuerstein BG. Chromosome transfer experiments link regions on chromosome 7 to radiation resistance in human glioblastoma multiforme. Genes Chromosomes Cancer 2006; 45:20-30. [PMID: 16130123 DOI: 10.1002/gcc.20257] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Glioblastoma multiforme (GM) is the most lethal form of brain tumor, with a median survival of approximately 1 year. Treatment options are limited. Radiation therapy is a common form of treatment, but many tumors are resistant. In earlier studies, we found that gain of chromosome 7 is associated with radiation resistance in human primary GM. In this study, we extend that result to a model system in which we transferred chromosome 7 to recipient cells and confirmed radiation resistance as a function of chromosome 7 gain. We identified three candidate regions on chromosome 7 that conferred radiation resistance in our model system.
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Affiliation(s)
- Anjan Misra
- Brain Tumor Research Center, Department of Neurosurgery, University of California San Francisco, San Francisco, CA 94143-0808, USA.
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717
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Moon MS, Kim JS, Kim TL, Yum JJ, Cho EW, Kim IG. Polyamine depletion partially reduces the radiation-induced cell death via cell cycle delay mediated by thioredoxin. Cell Biol Toxicol 2006; 22:137-47. [PMID: 16532286 DOI: 10.1007/s10565-006-0042-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Accepted: 01/05/2006] [Indexed: 11/29/2022]
Abstract
In previous studies, polyamine depletion by DFMO (alpha-difluoromethylornithine)-treatment reduced H(2)O(2)-induced apoptotic cell death by reduction of ferric ion uptake. In the present study, we analyzed the reduction of radiation-induced cell death by polyamine depletion. Exposure of HT29 cells to radiation induced severe cell death, but when cells were pretreated with DFMO, a specific inhibitor of polyamine biosynthesis, radiation-induced cell death was reduced to 50-60% of control. Cell cycle analysis showed that, in these cells, the time to reach the G(2)/M phase arrest was delayed for 20-24 h compared to the control cells, at which stage the fate of cells exposed to ionizing radiation is determined. DFMO-treated cells also showed a low level of thioredoxin, which is a high-level determinant of the cellular fate. To investigate the relationship between the G(2)/M phase arrest and the reduction of thioredoxin caused by polyamine depletion, we also analyzed thioredoxin-antisensed (asTRX) HT29 cells as for DFMO-treated cells. In asTRX-transfected cells, the gamma-irradiation-induced G(2)/M phase arrest was also significantly delayed and radiation-induced cell death was profoundly reduced, as in the DFMO-treated cells. Both sets of cells showed a decrease of cyclin D1 and an increment of HSP25, which are involved in radiation-induced cell cycle progress. Overall, these results suggest that polyamines are essential for normal cell death of HT29 cells triggered by gamma-radiation and that this is partially mediated by the regulation of thioredoxin expression.
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Affiliation(s)
- M S Moon
- Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, Yuseong, Daejon, Korea
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718
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Ribba B, Colin T, Schnell S. A multiscale mathematical model of cancer, and its use in analyzing irradiation therapies. Theor Biol Med Model 2006; 3:7. [PMID: 16472396 PMCID: PMC1388194 DOI: 10.1186/1742-4682-3-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Accepted: 02/10/2006] [Indexed: 12/21/2022] Open
Abstract
Background Radiotherapy outcomes are usually predicted using the Linear Quadratic model. However, this model does not integrate complex features of tumor growth, in particular cell cycle regulation. Methods In this paper, we propose a multiscale model of cancer growth based on the genetic and molecular features of the evolution of colorectal cancer. The model includes key genes, cellular kinetics, tissue dynamics, macroscopic tumor evolution and radiosensitivity dependence on the cell cycle phase. We investigate the role of gene-dependent cell cycle regulation in the response of tumors to therapeutic irradiation protocols. Results Simulation results emphasize the importance of tumor tissue features and the need to consider regulating factors such as hypoxia, as well as tumor geometry and tissue dynamics, in predicting and improving radiotherapeutic efficacy. Conclusion This model provides insight into the coupling of complex biological processes, which leads to a better understanding of oncogenesis. This will hopefully lead to improved irradiation therapy.
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Affiliation(s)
- Benjamin Ribba
- Institute for Theoretical Medicine and Clinical Pharmacology Department, Faculty of Medicine R.T.H Laennec, University of Lyon, Paradin St., P.O.B 8071, 69376 Lyon Cedex 08, France
| | - Thierry Colin
- Mathématiques Appliquées de Bordeaux, CNRS UMR 5466 and INRIA futurs, University of Bordeaux 1, 351 cours de la liberation, 33405 Talence Cedex, France
| | - Santiago Schnell
- Indiana University School of Informatics and Biocomplexity Institute, 1900 East Tenth Street, Eigenmann Hall 906, Bloomington, IN 47406, USA
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719
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Zlobec I, Steele R, Compton CC. VEGF as a predictive marker of rectal tumor response to preoperative radiotherapy. Cancer 2006; 104:2517-21. [PMID: 16222693 DOI: 10.1002/cncr.21484] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Neoadjuvant radiotherapy for rectal cancer may result in tumor downstaging or complete tumor regression leading to greater sphincter preservation. The identification of molecular predictive markers of tumor response to preoperative radiotherapy would provide an additional tool for selecting patients most likely to benefit from treatment. The aim of this study was to determine whether VEGF expression in preirradiation tumor biopsies is a useful predictive marker of tumor response in patients with rectal cancer undergoing preoperative radiotherapy. METHODS Immunohistochemistry for VEGF was performed on 59 preirradiation biopsies from patients with completely responsive (ypT0) or nonresponsive tumors after preoperative radiotherapy. VEGF positivity was evaluated using several scoring methods and the association between VEGF and tumor response was compared. The distribution of VEGF scores was obtained as well as the mean VEGF expression in the two response groups. RESULTS The mean VEGF expression in nonresponsive tumors (NR) was significantly greater than in completely responsive tumors (CR) (P = 0.0035). Nearly half (47%) of all CR tumors had a VEGF expression of 10% or less. Eleven tumors were negative (0% immunoreactivity) for the protein and all of these (100%) were complete responders. Fifty-two percent of the NR tumors had VEGF scores of 80% or greater. The four scoring methods used to determine the association between VEGF and tumor response each produced significant results (P < 0.05). CONCLUSIONS The results of this study indicate that VEGF assessed immunohistochemically from preirradiation tumor biopsies may be a useful marker of rectal tumor response to preoperative radiotherapy.
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Affiliation(s)
- Inti Zlobec
- Department of Pathology, McGill University, Montreal, Quebec, Canada.
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720
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Hata T, Yamamoto H, Ngan CY, Koi M, Takagi A, Damdinsuren B, Yasui M, Fujie Y, Matsuzaki T, Hemmi H, Xu X, Kitani K, Seki Y, Takemasa I, Ikeda M, Sekimoto M, Matsuura N, Monden M. Role of p21waf1/cip1 in effects of oxaliplatin in colorectal cancer cells. Mol Cancer Ther 2006; 4:1585-94. [PMID: 16227409 DOI: 10.1158/1535-7163.mct-05-0011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Clinical studies have shown that oxaliplatin, a novel platinum derivative, is a potent chemotherapeutic agent for colorectal cancer when combined with 5-fluorouracil and leucovorin. Although the toxic activity is based on covalent adducts between platinum and DNA, its actual biological behavior is mostly unknown. In an effort to explore the mechanism of tumor susceptibility to oxaliplatin, we examined the cytotoxic effects of oxaliplatin in colorectal cancer cell lines in reference to p53 gene status. Although p53 gene status did not clearly predict sensitivity to oxaliplatin, p53 wild-type cells including HCT116 were sensitive but HCT116 p53-/- were found to be resistant to oxaliplatin. Oxaliplatin caused strong p21waf1/cip1 induction and G0-G1 arrest in p53 wild-type cells, whereas cisplatin did not induce G0-G1 arrest. Assays using p53 wild but p21waf1/cip1 null HCT116 cells revealed that oxaliplatin did not show G0-G1 arrest and reduced growth-inhibitory effects, suggesting that p21waf1/cip1 may be a key element in oxaliplatin-treated p53 wild-type cells. Although HCT116 is DNA mismatch repair-deficient, a mismatch repair-proficient HCT116+ch3 cell line displayed similar responses with regard to p21waf1/cip1-mediated growth inhibition and G0-G1 arrest. In p53 mutant cells, on the other hand, oxaliplatin caused an abrupt transition from G1 to S phase and eventually resulted in G2-M arrest. This abrupt entry into S phase was associated with loss of the p21waf1/cip1 protein via proteasome-mediated degradation. These findings suggest that p21waf1/cip1 plays a role in oxaliplatin-mediated cell cycle and growth control in p53-dependent and -independent pathways.
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Affiliation(s)
- Taishi Hata
- Department of Surgery and Clinical Oncology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita City, Osaka 565-0871, Japan
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721
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Chen JH, Ozanne SE, Hales CN. Heterogeneity in premature senescence by oxidative stress correlates with differential DNA damage during the cell cycle. DNA Repair (Amst) 2006; 4:1140-8. [PMID: 16006199 DOI: 10.1016/j.dnarep.2005.06.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 05/31/2005] [Accepted: 06/02/2005] [Indexed: 11/23/2022]
Abstract
The development of cellular senescence both by replication and by oxidative stress is not homogenous in cultured primary human fibroblasts. To investigate whether this is due to the heterogeneity in the susceptibility of DNA in different phases of the cell cycle, we subjected synchronised cells to oxidative stress and examined the extent of DNA damage and its long-term effects on the induction of cellular senescence. Here, we first show marked heterogeneity in DNA damage as detected by markers of double strand breaks caused by oxidative stress in an asynchronous human fibroblast culture. Cell cycle synchronization followed by oxidative stress demonstrated that DNA in S-phase is most susceptible to oxidative stress whereas DNA in the quiescent phase is most resistant. DNA repair is an ongoing process after sensing DNA damage; reparable DNA damage is repaired even in cells that contain persistent DNA damage. The extent of persistent DNA damage is tightly correlated with permanent cessation of DNA replication and SA-beta-gal activity. Oxidative stress encountered by cells in S-phase resulted in more persistent DNA damage, more permanent cell cycle arrest and the induction of premature senescence.
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Affiliation(s)
- Jian-Hua Chen
- Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital Level 4, Hills Road, Cambridge CB2 2QR, UK.
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722
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Verheyde J, de Saint-Georges L, Leyns L, Benotmane MA. The Role of Trp53 in the Transcriptional Response to Ionizing Radiation in the Developing Brain. DNA Res 2006; 13:65-75. [PMID: 16766514 DOI: 10.1093/dnares/dsi028] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Brain formation results from a series of well-timed consecutive waves of cellular proliferation, migration and differentiation. Acute irradiation during pregnancy selectively interferes with these events to result in malformations such as microcephaly, reduced cortical thickness and mental retardation. In the present study we performed a straight-through cDNA-microarray analysis of the developing mouse brain at embryonic day E13, 3 h after in utero exposure to 50 cGy X-radiation. This dataset was used as an indication of genes involved in different pathways that are activated upon early radiation exposure, and for further evaluation using quantitative PCR (qPCR). Microarray and qPCR data revealed that the main activated pathways in irradiated wild-type embryos are involved in the regulation of a p53-mediated pathway that may lead to cell cycle delay/arrest and increased levels of apoptosis. To define whether the transcriptional radiation response was solely p53 mediated, we analysed the expression of cell cycle regulating genes in a Trp53 null mutant. The modulated expression of cell cycle regulating genes such as cyclins and Cdk genes indicated the induction of a cell cycle arrest, without evidence for the onset of apoptosis. Additional gene-expression studies have shown that various E2F transcription factors may be involved in this event. Together, these results provide a detailed view of the different p53-related mechanisms that are triggered in response to ionizing radiation in the developing brain.
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Affiliation(s)
- J Verheyde
- Laboratory of Radiobiology, Studiecentrum voor Kernenergie/Centre d'étude de l'Energie Nucléaire (SCK.CEN) Boeretang 200, Mol B-2400, Belgium
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723
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Hemström TH, Sandström M, Zhivotovsky B. Inhibitors of the PI3-kinase/Akt pathway induce mitotic catastrophe in non-small cell lung cancer cells. Int J Cancer 2006; 119:1028-38. [PMID: 16570272 DOI: 10.1002/ijc.21927] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Non-small cell lung cancer cells (NSCLC) are more resistant to anticancer treatment as compared with other types of cancer cells. Recently (Hemström et al., Exp Cell Res 2005;305:200-13) we showed that apoptosis of U1810 NSCLC cells induced by the staurosporine analog PKC 412 correlated with inhibition of Akt and ERK1/2, suggesting the involvement of these kinases in cell survival. Here we investigated the contribution of the PI3-kinase/Akt and MEK/ERK pathways to survival of NSCLC cells. The two signaling pathways were studied by using different combinations of the PI3-kinase inhibitors LY-294002 and wortmannin, the Akt activator Ro 31-8220, the MEK inhibitor PD 98059 and PKC 412. PI3-kinase inhibitors induced apoptosis-like death in U1810 cells. H157 cells in general were relatively resistant to PI3 kinase/Akt inhibitors yet these compounds sensitized cells to the DNA-damaging drug VP-16, while Ro 31-8220 could not. PD 98059 only had a sensitizing effect on H157 cells when combined with PI3-kinase inhibition and VP-16. Morphological data indicated that LY-294002 and PKC 412 induced cell death at anaphase and metaphase, respectively, suggesting death by mitotic catastrophe. Analyzes of cells blocked in G2/M-phase by nocodazol revealed that LY-294002 increased, while PKC 412 decreased histone H3 phosphorylation, suggesting that LY-294002 allowed, while PKC 412 inhibited cells to leave M-phase. Flow cytometric analysis of cell cycle distribution demonstrated that LY-294002 allowed cells to leave G2/M phase, while PKC 412 inhibited cytokinesis, resulting in formation of multinucleated cells. These results indicate that sensitization of NSCLC cells by PI3-kinase inhibition involves interplay between cell cycle regulation, mitotic catastrophe and apoptosis.
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Affiliation(s)
- Therese H Hemström
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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724
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Crokart N, Jordan BF, Baudelet C, Ansiaux R, Sonveaux P, Grégoire V, Beghein N, DeWever J, Bouzin C, Feron O, Gallez B. Early reoxygenation in tumors after irradiation: determining factors and consequences for radiotherapy regimens using daily multiple fractions. Int J Radiat Oncol Biol Phys 2005; 63:901-10. [PMID: 16199320 DOI: 10.1016/j.ijrobp.2005.02.038] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Revised: 01/19/2005] [Accepted: 02/21/2005] [Indexed: 11/24/2022]
Abstract
PURPOSE To characterize changes in the tumor microenvironment early after irradiation and determine the factors responsible for early reoxygenation. METHODS AND MATERIALS Fibrosarcoma type II (FSaII) and hepatocarcinoma transplantable liver tumor tumor oxygenation were determined using electron paramagnetic resonance oximetry and a fiberoptic device. Perfusion was assessed by laser Doppler, dynamic contrast-enhanced MRI, and dye penetration. Oxygen consumption was determined by electron paramagnetic resonance. The interstitial fluid pressure was evaluated by the wick-in-needle technique. RESULTS An increase in oxygen partial pressure was observed 3-4 h after irradiation. This increase resulted from a decrease in global oxygen consumption and an increase in oxygen delivery. The increase in oxygen delivery was due to radiation-induced acute inflammation (that was partially inhibited by the antiinflammatory agent diclofenac) and to a decrease in interstitial fluid pressure. The endothelial nitric oxide synthase pathway, identified as a contributing factor at 24 h after irradiation, did not play a role in the early stage after irradiation. We also observed that splitting a treatment of 18 Gy into two fractions separated by 4 h (time of maximal reoxygenation) had a greater effect on tumor regrowth delay than when applied as a single dose. CONCLUSION Although the cell cycle redistribution effect is important for treatment protocols using multiple daily radiation fractions, the results of this work emphasize that the oxygen effect must be also considered to optimize the treatment strategy.
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Affiliation(s)
- Nathalie Crokart
- Laboratory of Medicinal Chemistry and Radiopharmacy, Université Catholique de Louvain, Brussels, Belgium
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725
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Wu DT, Bitzer M, Ju W, Mundel P, Böttinger EP. TGF-β Concentration Specifies Differential Signaling Profiles of Growth Arrest/Differentiation and Apoptosis in Podocytes. J Am Soc Nephrol 2005; 16:3211-21. [PMID: 16207831 DOI: 10.1681/asn.2004121055] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Podocyte depletion occurs in most progressive glomerular diseases and is thought to result from podocyte loss while the remaining podocytes are unable to proliferate. The underlying mechanisms for podocyte growth arrest/differentiation and depletion remain poorly understood but may involve TGF-beta, which is typically upregulated in injured glomeruli. The TGF-beta are multifunctional cytokines that regulate growth, differentiation, and apoptosis in most cells. Determinants of functional specificity of TGF-beta signaling in cell-cycle control and apoptosis remain poorly understood. Using a unique system of conditionally immortalized podocytes, it is demonstrated that autocrine TGF-beta2 induces G0/G1 arrest and differentiation under nonpermissive culture through Smad3-dependent induction of the cyclin-dependent kinase inhibitor p15(Ink4b) (Cdkn2b). When exposed to recombinant TGF-beta1 (or TGF-beta2), nonpermissive culture podocytes switch to G2/M arrest and apoptosis, selectively at advanced TGF-beta concentrations and specifically in association with suppression of Cdkn2b and activation of proapoptotic p38 mitogen-activated protein kinase. Thus, distinct signaling profiles activated in a concentration-dependent manner by TGF-beta were identified. Autocrine TGF-beta2/Smad3/Cdkn2b signaling in podocytes specifies G0/G1 arrest associated with podocyte differentiation, whereas increasing TGF-beta concentrations beyond a critical threshold induces G2/M block and apoptosis associated with selective p38 mitogen-activated protein kinase activation and with suppression of Cdkn2b. In summary, the results suggest a new functional requirement of TGF-beta2 in growth arrest and differentiation of murine podocytes in vitro and demonstrate that a critical TGF-beta concentration threshold may specify a molecular switch to proapoptotic signaling profiles and apoptosis.
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Affiliation(s)
- Dona T Wu
- Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
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726
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Bolige A, Kiyota M, Goto K. Circadian rhythms of resistance to UV-C and UV-B radiation in Euglena as related to ‘escape from light’ and ‘resistance to light’. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2005; 81:43-54. [PMID: 16111890 DOI: 10.1016/j.jphotobiol.2005.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2005] [Revised: 05/18/2005] [Accepted: 06/12/2005] [Indexed: 11/24/2022]
Abstract
Radiation-induced stress, either from visible or UV light, is strongest at midday. We found that, in the absence of stress or time cues, Euglena gracilis Z was the most resistant to UV-C and UV-B at subjective midday, whether judged from immediate or reproductive survival. The circadian UV-resistance rhythms were free-running in stationary cultures under 1-h light/1-h dark cycles or continuous darkness, indicating that cell-cycle dependent DNA susceptibility to UV was not involved. We moreover examined what was the primary cause of the circadian UV resistance, estimated as the immediate cell survival. The half-maximal lethal dose (LD(50)) of UV-C at subjective midday (the most resistant phase) was 156 J/m(2), which is approximately 3-fold that at subjective midnight. The same was true for UV-B, except the LD(50) was approximately 13-fold that of UV-C. Temperature during UV irradiation had little effect, indicating that survival was not mediated via enzymatic reactions. Non-enzymatic antioxidants were added 5 min before UV irradiation. Dimethylsulfoxide (a hydroxyl radical scavenger) increased survival after UV-B, but had little effect after UV-C; conversely, sodium ascorbate increased survival after UV-C, but not after UV-B. These findings suggest that circadian rhythms of resistance to UVs involve a common mechanism for maximizing non-enzymatic antioxidative capacity at subjective midday, but the specific antioxidants differ.
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Affiliation(s)
- Aoen Bolige
- Laboratory of Biological Rhythms, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan
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727
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Toillon RA, Magné N, Laïos I, Lacroix M, Duvillier H, Lagneaux L, Devriendt D, Van Houtte P, Leclercq G. Interaction Between Estrogen Receptor Alpha, Ionizing Radiation and (anti-) Estrogens in Breast Cancer Cells. Breast Cancer Res Treat 2005; 93:207-15. [PMID: 16136271 DOI: 10.1007/s10549-005-5148-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE Estrogen receptor alpha (ERalpha) plays a major role in breast cancer development. It acts as ligand-inducible transcription factor which determines growth, survival and differentiation of breast cancer cells. The aim of this study is to evaluate the potential interference between radiotherapy and estrogen receptor responsiveness. Materials and methods. The effect of ionizing radiation was assessed on the estrogen receptor alpha status, growth (proliferation and apoptosis) and sensitivity of MCF-7 breast cancer cells to estrogenic (17beta-estradiol (E2)), selective estrogen receptor modulator (SERM) and anti-estrogenic compounds. Results. We have observed a ligand-independent decrease in ERalpha expression after radiation, resulting from a specific reduction in mRNA level and protein synthesis. This ERalpha disappearance occurred 72 h post-irradiation at 8 Gy and decreased the transcriptional activity in ERalpha of these cells. On the other hand, E2 impedes the growth inhibitory effects (essentially on proliferation) of ionizing radiation in MCF-7 cells, which potentially decreases radiosensitivity of these cells. This effect was totally blocked by SERM and anti-estrogenic treatments. Moreover, this growth effect of concurrent anti-estrogenic drugs and ionizing radiation appeared to be strongly synergistic. CONCLUSIONS This study may increase general comprehension of ERalpha modulation by radiotherapy and improve adjuvant therapeutic approaches based on co-administration of radiation and endocrine therapy.
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Affiliation(s)
- R A Toillon
- Laboratoire Jean-Claude Heuson de Cancérologie Mammaire Institut Jules Bordet, Université Libre de Bruxelles, Bruxelles, Belgium
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728
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Zlobec I, Steele R, Nigam N, Compton CC. A Predictive Model of Rectal Tumor Response to Preoperative Radiotherapy Using Classification and Regression Tree Methods. Clin Cancer Res 2005; 11:5440-3. [PMID: 16061859 DOI: 10.1158/1078-0432.ccr-04-2587] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The ability to predict rectal tumor response to preoperative radiotherapy before treatment would significantly impact patient selection. In this study, classification and regression tree (CART) methods were used to model tumor response to preoperative conformal high-dose rate brachytherapy by assessing the predictive value of vascular endothelial growth factor (VEGF), Bcl-2, p21, p53, and APAF-1. EXPERIMENTAL DESIGN Immunohistochemistry was used to detect VEGF, Bcl-2, p21, p53, and APAF-1 from 62 pretreatment rectal tumor biopsies. Scores were assigned as percentages of positive tumor cell staining and were used in CART analysis to identify the proteins that best predicted response to radiotherapy. Ten-fold cross-validation was used to prevent overfitting and multiple cross-validation experiments were run to estimate the prediction error. RESULTS Postoperative pathologic evaluation of the irradiated tumor bed revealed 43 responsive tumors [20 with complete response (T(0)) and 23 with partial response] and 19 nonresponsive tumors. The optimal tree resulting from CART analysis had five terminal nodes with a misclassification rate of 18%. Of the five proteins selected for their predictive value, VEGF and Bcl-2 contributed most to the classification of responsive and nonresponsive tumors. All 10 tumors with no VEGF were completely responsive (T(0)) to radiotherapy; 85% of those with VEGF and negative for Bcl-2 were responsive to therapy. CONCLUSIONS VEGF and Bcl-2 status in pretreatment rectal tumor biopsies may be predictive of response to preoperative high-dose rate brachytherapy.
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Affiliation(s)
- Inti Zlobec
- Department of Pathology, McGill University Health Centre, Montreal, Quebec, Canada.
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729
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Hofstetter B, Vuong V, Broggini-Tenzer A, Bodis S, Ciernik IF, Fabbro D, Wartmann M, Folkers G, Pruschy M. Patupilone acts as radiosensitizing agent in multidrug-resistant cancer cells in vitro and in vivo. Clin Cancer Res 2005; 11:1588-96. [PMID: 15746064 DOI: 10.1158/1078-0432.ccr-04-1800] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Interference with microtubule function is a promising antitumoral concept. Paclitaxel is a clinically validated tubulin-targeting agent; however, treatment with paclitaxel is often limited by taxane-related toxicities and is ineffective in tumors with multidrug-resistant cells. Patupilone (EPO906, epothilone B) is a novel non-taxane-related microtubule-stabilizing natural compound that retains full activity in multidrug-resistant tumors and is clinically less toxic than paclitaxel. Here we have investigated the effect of combined treatment with ionizing radiation and patupilone or paclitaxel in the P-glycoprotein-overexpressing, p53-mutated human colon adenocarcinoma cell line SW480 and in murine, genetically defined E1A/ras-transformed paclitaxel-sensitive embryo fibroblasts. Patupilone and paclitaxel alone and in combination with ionizing radiation reduced the proliferative activity of the E1A/ras-transformed cell line with similar potency in the sub and low nanomolar range. SW480 cells were only sensitive to patupilone, and combined treatment with low-dose patupilone (0.1 nmol/L) followed by clinically relevant doses of ionizing radiation (2 and 5 Gy) resulted in a supra-additive cytotoxic effect. Inhibition of the drug efflux protein P-glycoprotein with verapamil resensitized SW480 cells to treatment with low doses of paclitaxel alone and in combination with IR. In tumor xenografts derived from SW480 cells a minimal treatment regimen with patupilone and fractionated irradiation (1 x 2 mg/kg plus 4 x 3 Gy) resulted in an at least additive tumor response with extended tumor growth arrest. Analysis by flow cytometry in vitro revealed an apoptosis- and G(2)-M-independent mode of radiosensitization by patupilone. Interestingly though, a transient accumulation of cells in S phase was observed on combined treatment.Overall, patupilone might be a promising alternative in paclitaxel-resistant, P-glycoprotein-overexpressing tumors for a combined treatment regimen using ionizing radiation and a microtubule inhibitor.
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Affiliation(s)
- Barbara Hofstetter
- Department of Radiation Oncology, University Hospital Zurich, Ramistr. 100, CH-8091 Zurich, Switzerland
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730
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Goel A, Dispenzieri A, Greipp PR, Witzig TE, Mesa RA, Russell SJ. PS-341–mediated selective targeting of multiple myeloma cells by synergistic increase in ionizing radiation-induced apoptosis. Exp Hematol 2005; 33:784-95. [PMID: 15963854 DOI: 10.1016/j.exphem.2005.04.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 03/28/2005] [Accepted: 04/14/2005] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Multiple myeloma remains incurable with current therapy. The proteosome inhibitor, PS-341, has shown objective clinical responses in relapsed refractory myeloma patients. We investigated the potential of enhancing the radiosensitivity of myeloma cells by combining with PS-341; the underlying mechanisms were delineated. MATERIALS AND METHODS Clonogenic assays were used to evaluate cell survival after exposure to PS-341, ionizing radiation (IR), or PS-341 followed by IR. Apoptosis was studied by annexin V-propidium iodide staining and caspase activation. Cell-cycle phase distribution of cells was determined. Nuclear factor-kappaB (NF-kappaB) activity was monitored by enzyme-linked immunosorbent assay and Western blotting. The expression of death receptor Fas/APO-1/CD95 was analyzed by flow cytometry. The consequential caspase-8 activation was detected by Western blotting. RESULTS In clonogenic assays, sequential exposure to nontoxic doses of PS-341 (10 nM) and IR (6 Gy) resulted in synergistic inhibition of proliferation of myeloma cells by modulating the apoptotic sensitivity of these cells. Biochemically, sublethal dose of IR led to potent induction of NF-kappaB activity, and this response was significantly inhibited by pretreatment with PS-341, or by the NF-kappaB inhibitory peptide SN-50. Enhanced Fas expression was seen in myeloma cells exposed sequentially to PS-341 and IR. Finally, PS-341 sensitized primary myeloma (CD138+ve) cells to IR but had little effect on CD138-ve bone marrow cells from myeloma patients. CONCLUSION These data indicate that PS-341 can sensitize myeloma cells to IR by both intrinsic and extrinsic apoptotic pathways. The study indicates improved therapeutic benefits in treatment of multiple myeloma by combining PS-341 with conventional radiotherapy.
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Affiliation(s)
- Apollina Goel
- Molecular Medicine Program, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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McHugh MM, Gawron LS, Matsui SI, Beerman TA. The Antitumor Enediyne C-1027 Alters Cell Cycle Progression and Induces Chromosomal Aberrations and Telomere Dysfunction. Cancer Res 2005; 65:5344-51. [PMID: 15958582 DOI: 10.1158/0008-5472.can-05-0015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study examined the extent of chromosome instability induced in cultured human colon carcinoma HCT116 cells by the antitumor radiomimetic enediyne antibiotic C-1027. Spectral karyotype analysis showed frequent intrachromosomal fusions and fragmentations 26 hours after addition of as little as 0.035 nmol/L C-1027. When the concentration was increased to 0.14 nmol/L C-1027, 92% of cells showed chromosomal aberrations compared with only 2.9% after treatment with an equivalent growth inhibitory dose of ionizing radiation (20 Gy). Thus, chromosome misrejoining was associated to a much greater extent with C-1027-induced than with ionizing radiation-induced cell growth inhibition. Despite these aberrations, a large fraction of C-1027-treated cells progressed into G1. Comet analysis showed that these extensive chromosomal anomalies were not due to increased induction or reduced repair of C-1027-induced compared with ionizing radiation-induced strand breaks. Fluorescence in situ hybridization analysis showed that misrejoining of telomere repeats (i.e., chromosomes joined end to end at their telomeres or fused together after complete loss of telomere sequences) was observed within 26 hours of C-1027 addition. The extreme cytotoxicity of C-1027 may reflect both induction and erroneous repair of DNA double-strand break in the whole genome and/or in subgenomic targets such as telomere sequences.
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Affiliation(s)
- Mary M McHugh
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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