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Li D, Ren T, Wang X, Xiao Z, Sun G, Zhang N, Zhao L, Zhong R. Development and in vitro evaluation of carmustine delivery platform: A hypoxia-sensitive anti-drug resistant nanomicelle with BBB penetrating ability. Biomed Pharmacother 2023; 167:115631. [PMID: 37804814 DOI: 10.1016/j.biopha.2023.115631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/09/2023] Open
Abstract
Glioma is extremely difficult to be completely excised by surgery due to its invasive nature. Thus, chemotherapy still is the mainstay in the treatment of glioma after surgery. However, the natural blood-brain barrier (BBB) greatly restricts the penetration of chemotherapeutic agents into the central nervous system. As a front-line anti-glioma agent in clinical, carmustine (BCNU) exerts antitumor effect by inducing DNA damage at the O6 position of guanine. However, the therapeutic effect of BCNU was largely decreased because of the drug resistance mediated by O6-alkylguanine-DNA alkyltransferase (AGT) and insufficient local drug concentrations. To overcome these obstacles, we synthesized a BCNU-loaded hypoxia-responsive nano-micelle with BBB penetrating capacity and AGT inhibitory activity, named as T80-HA-AZO-BG/BCNU NPs. In this nano-system, Tween 80 (T80) serves as a functional coating on the surface of the micelle, promoting transportation across the BBB. Hyaluronic acid (HA) with active tumor-targeting capability was linked with the hydrophobic O6-benzylguanine (BG) analog via a hypoxia-sensitive azo bond. Under hypoxic tumor microenvironment, the azo bond selectively breaks to release O6-BG as AGT inhibitor and BCNU as DNA alkylating agent. The synthesized T80-HA-AZO-BG/BCNU NPs showed good stability, favorable biocompatibility and hypoxia-responsive drug-releasing ability. T80 modification improved the transportation of the micelle across an in vitro BBB model. Moreover, T80-HA-AZO-BG/BCNU NPs exhibited significantly enhanced cytotoxicity against glioma cell lines with high AGT expression compared with traditional combined medication of BCNU plus O6-BG. We expect that the tumor-targeting nano-micelle designed for chloroethylnitrosourea will provide new tools for the development of effective glioma therapy.
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Affiliation(s)
- Duo Li
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Ting Ren
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Xiaoli Wang
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Zhixuan Xiao
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Guohui Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Na Zhang
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China.
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
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Li D, Wang X, Han K, Sun Y, Ren T, Sun G, Zhang N, Zhao L, Zhong R. Hypoxia and CD44 receptors dual-targeted nano-micelles with AGT-inhibitory activity for the targeting delivery of carmustine. Int J Biol Macromol 2023; 246:125657. [PMID: 37399878 DOI: 10.1016/j.ijbiomac.2023.125657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 02/17/2023] [Accepted: 06/30/2023] [Indexed: 07/05/2023]
Abstract
Carmustine (BCNU) is a typical chemotherapy used for treatment of cerebroma and other solid tumors, which exerts antitumor effect by inducing DNA damage at O6 position of guanine. However, the clinical application of BCNU was extremely limited due to the drug resistance mainly mediated by O6-alkylguanine-DNA alkyltransferase (AGT) and absence of tumor-targeting ability. To overcome these limitations, we developed a hypoxia-responsive nanomicelle with AGT inhibitory activity, which was successfully loaded with BCNU. In this nano-system, hyaluronic acid (HA) acts as an active tumor-targeting ligand to bind the overexpressing CD44 receptors on the surface of tumor cells. An azo bond selectively breaks in hypoxic tumor microenvironment to release O6-benzylguanine (BG) as AGT inhibitor and BCNU as DNA alkylating agent. The obtained HA-AZO-BG NPs with shell core structure had an average particle size of 176.98 ± 11.19 nm and exhibited good stability. Meanwhile, HA-AZO-BG NPs possessed a hypoxia-responsive drug release profile. After immobilizing BCNU into HA-AZO-BG NPs, the obtained HA-AZO-BG/BCNU NPs exhibited obvious hypoxia-selectivity and superior cytotoxicity in T98G, A549, MCF-7 and SMMC-7721 cells with IC50 at 189.0, 183.2, 90.1 and 100.1 μm, respectively, under hypoxic condition. Near-infrared imaging in HeLa tumor xenograft models showed that HA-AZO-BG/DiR NPs could effectively accumulate in tumor site at 4 h of post-injection, suggesting its good tumor-targetability. In addition, in vivo anti-tumor efficacy and toxicity evaluation indicated that HA-AZO-BG/BCNU NPs was more effective and less harmful compared to the other groups. After treatment, the tumor weight of HA-AZO-BG/BCNU NPs group was 58.46 % and 63.33 % of the control group and BCNU group, respectively. Overall, HA-AZO-BG/BCNU NPs was expected to be a promising candidate for targeted delivery of BCNU and elimination of chemoresistance.
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Affiliation(s)
- Duo Li
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Xiaoli Wang
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Kaishuo Han
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Yaqian Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Ting Ren
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Guohui Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Na Zhang
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China.
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
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Tang Q, Cao H, Tong N, Liu Y, Wang W, Zou Y, Xu L, Zeng Z, Xu W, Yin Z, Ma W, Wang Q. Tubeimoside-I sensitizes temozolomide-resistant glioblastoma cells to chemotherapy by reducing MGMT expression and suppressing EGFR induced PI3K/Akt/mTOR/NF-κB-mediated signaling pathway. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 99:154016. [PMID: 35278900 DOI: 10.1016/j.phymed.2022.154016] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/20/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Glioblastoma multiforme (GBM, World Health Organization [WHO] grade IV) is one of the malignant Central Nerve System (CNS) tumors with high incidence rate and poor prognosis. The use of alkylating agents, such as temozolomide (TMZ), has been the main method of cytotoxic therapy for glioma patients for decades. However, TMZ resistance may be one of the major reasons for treatment failure, so far. In searching for effective agents to reverse TMZ resistance, we found that Tubeimoside-I (TBMS1), a saponin from traditional Chinese medicine, Bolbostemma paniculatum (Maxim.) Franquet, showed activities of reversing TMZ resistance of GBM. However, the ability of TBMS1 enhancing the chemosensitivity of GBM has been rarely studied, and its underlying mechanisms remain unclear. PURPOSE This study purposes to reveal the synergistic effects and mechanism of TBMS1 and TMZ against TMZ-resistant GBM cells. METHODS CCK8 assay was used to investigate the anti-proliferative effects on grade IV glioblastoma human T98G and U118 MG cells. Cell proliferation was determined by EdU assay and clonogenic assay after TMZ plus TBMS1 treatment. Apoptosis was analyzed by flow cytometry. DNA damage and DNA Double Strand Break (DSB) were assessed by cleaved Poly (ADP-ribose) polymerase (PARP), γH2AX Foci Assay and Comet Assay, respectively. Expression of proteins associated with apoptosis and DNA repair enzymes were measured by Western blot analysis. The prognostic significance of key proteins of the epidermal growth factor receptor (EGFR) induced PI3K/Akt/mTOR/NF-κB signaling pathway was analyzed using GEPIA (http://gepia.cancer-pku.cn) and validated by Western blotting. RESULTS Here we demonstrated that TBMS1 sensitized TMZ-resistant T98G and U118 MG glioblastoma cells to chemotherapy and exhibited promotion of apoptosis and inhibition on cell viability, proliferation and clone formation. Coefficient of drug in interaction (CDI) values showed a notable synergistic effect between TBMS1 and TMZ. Moreover, we observed that combination of TBMS1 and TMZ induced apoptosis was accompanied by robust DSB, γH2AX Foci formation and increasing cleaved PARP, as well as the heightened ratio of Bax/Bcl-2, cleavages of caspase-3 and caspase-9. In addition, the synergistic anti-glioma effect between TBMS1 and TMZ was intimately related to the reduction of MGMT expression in TMZ-resistant GBM cells. Moreover, it was also associated with attenuated expression of EGFR, p-PI3K-p85, p-Akt (Ser473), p-mTOR (Ser2481) and p-NF-κB p65(Ser536), which implying deactivation of the EGFR induced PI3K/Akt/mTOR/NF-κB signaling pathway. CONCLUSION We first demonstrated that synergistic effects of TBMS1 and TMZ induced apoptosis in GBM cells through reducing MGMT expression and inhibiting the EGFR induced PI3K/Akt/mTOR/NF-κB signaling pathway. This study provides a rationale for combined application of TMZ and TBMS1 as a potential chemotherapeutic treatment for MGMT+ GBM patients.
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Affiliation(s)
- Qingfa Tang
- Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong 510282, China; School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China; Guangdong Provincial Key Laboratory of Chinese Medicine Pharmaceutics, Guangzhou, 510515, China
| | - Haihong Cao
- Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong 510282, China; School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Ni Tong
- Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong 510282, China; School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Yuanliang Liu
- Department of Pathology, Guangzhou First People's Hospital, Guangzhou, Guangdong 510180, China
| | - Wanyu Wang
- Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong 510282, China; School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Yuheng Zou
- Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong 510282, China; School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Lanyang Xu
- Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong 510282, China; School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Zhiyun Zeng
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Wei Xu
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Zhixin Yin
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Wenjuan Ma
- Department of Intensive Care Unit, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong, 510060, China.
| | - Qirui Wang
- Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong 510282, China; School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China.
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Liu Q, Wang X, Li J, Wang J, Sun G, Zhang N, Ren T, Zhao L, Zhong R. Development and biological evaluation of AzoBGNU: A novel hypoxia-activated DNA crosslinking prodrug with AGT-inhibitory activity. Biomed Pharmacother 2021; 144:112338. [PMID: 34678728 DOI: 10.1016/j.biopha.2021.112338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/09/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022] Open
Abstract
Chloroethylnitrosoureas (CENUs) are an important family of chemotherapies in clinical treatment of cancers, which exert antitumor activity by inducing the formation of DNA interstrand crosslinks (dG-dC ICLs). However, the drug resistance mediated by O6-alkylguanine-DNA alkyltransferase (AGT) and absence of tumor-targeting ability largely decrease the antitumor efficacy of CENUs. In this study, we synthesized an azobenzene-based hypoxia-activated combi-nitrosourea prodrug, AzoBGNU, and evaluated its hypoxic selectivity and antitumor activity. The prodrug was composed of a CENU pharmacophore and an O6-benzylguanine (O6-BG) analog moiety masked by a N,N-dimethyl-4-(phenyldiazenyl)aniline segment as a hypoxia-activated trigger, which was designed to be selectively reduced via azo bond break in hypoxic tumor microenvironment, accompanied with releasing of an O6-BG analog to inhibit AGT and a chloroethylating agent to induce dG-dC ICLs. AzoBGNU exhibited significantly increased cytotoxicity and apoptosis-inducing ability toward DU145 cells under hypoxia compared with normoxia, indicating the hypoxia-responsiveness as expected. Predominant higher cytotoxicity was observed in the cells treated by AzoBGNU than those by traditional CENU chemotherapy ACNU and its combination with O6-BG. The levels of dG-dC ICLs in DU145 cells induced by AzoBGNU was remarkably enhanced under hypoxia, which was approximately 6-fold higher than those in the AzoBGNU-treated groups under normoxia and those in the ACNU-treated groups. The results demonstrated that azobenzene-based combi-nitrosourea prodrug possessed desirable tumor-hypoxia targeting ability and eliminated chemoresistance compared with the conventional CENUs.
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Affiliation(s)
- Qi Liu
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Xiaoli Wang
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Jun Li
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Jiaojiao Wang
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Guohui Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Na Zhang
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Ting Ren
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China.
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental & Viral Oncology, Faculty of Environment & Life, Beijing University of Technology, Beijing 100124, China
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Depletion of tyrosyl DNA phosphodiesterase 2 activity enhances etoposide-mediated double-strand break formation and cell killing. DNA Repair (Amst) 2016; 43:38-47. [DOI: 10.1016/j.dnarep.2016.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 11/20/2022]
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Shirakami Y, Gottesman ME, Blaner WS. Diethylnitrosamine-induced hepatocarcinogenesis is suppressed in lecithin:retinol acyltransferase-deficient mice primarily through retinoid actions immediately after carcinogen administration. Carcinogenesis 2011; 33:268-74. [PMID: 22116467 DOI: 10.1093/carcin/bgr275] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Loss of retinoid-containing lipid droplets upon hepatic stellate cell (HSC) activation is one of the first events in the development of liver disease leading to hepatocellular carcinoma. Although retinoid stores are progressively lost from HSCs during the development of hepatic disease, how this affects hepatocarcinogenesis is unclear. To investigate this, we used diethylnitrosamine (DEN) to induce hepatic tumorigenesis in matched wild-type (WT) and lecithin:retinol acyltransferase (LRAT) knockout (KO) mice, which lack stored retinoid and HSC lipid droplets. Male 15-day-old WT or Lrat KO mice were given intraperitoneal injections of DEN (25 mg/kg body wt). Eight months later, Lrat KO mice showed significantly less liver tumor development compared with WT mice, characterized by less liver tumor incidence and smaller tumor size. Two days after DEN injection, lower serum levels of alanine aminotransferase and decreased hepatic levels of cyclin D1 were observed in Lrat KO mice. Lrat KO mice also exhibited increased levels of retinoic acid-responsive genes, including p21, lower levels of cytochrome P450 enzymes required for DEN bioactivation and higher levels of the DNA repair enzyme O(6)-methylguanine-DNA methyltransferase (MGMT), both before and after DEN treatment. Our results indicate that Lrat KO mice are less susceptible to DEN-induced hepatocarcinogenesis due to increased retinoid signaling and higher expression of p21, which is accompanied by altered hepatic levels of DEN-activating enzymes and MGMT in Lrat KO mice also contribute to decreased cancer initiation and suppressed liver tumor development.
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Affiliation(s)
- Yohei Shirakami
- Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA
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Pytel P, Lukas RV. Update on diagnostic practice: tumors of the nervous system. Arch Pathol Lab Med 2009; 133:1062-77. [PMID: 19642733 DOI: 10.5858/133.7.1062] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2008] [Indexed: 11/06/2022]
Abstract
CONTEXT Changes in the practice of diagnosing brain tumors are formally reflected in the evolution of the World Health Organization classification. Beyond this classification, the practice of diagnostic pathology is also changing with the availability of new tests and the introduction of new treatment options. OBJECTIVE Glioblastomas, oligodendrogliomas, glioneuronal tumors, and primitive pediatric tumors are discussed in an exemplary way to illustrate these changes. DATA SOURCES Review of relevant publications through Medline database searches. CONCLUSIONS The example of glioblastomas shows how new predictive markers may help identify subgroups of tumors that respond to certain therapy regimens. The development of new treatment strategies also leads to different questions in the assessment of brain tumors, as seen in the example of pseudoprogression or the changes in tumor growth pattern in patients taking bevacizumab. Oligodendrogliomas illustrate how the identification of 1p/19q loss as a cytogenetic aberration aids our understanding of these tumors and changes diagnostic practice but also introduces new challenges in classification. Glioneuronal tumors are an evolving group of lesions. Besides a growing list of usually low-grade entities with well-defined morphologic features, these also include more poorly defined cases in which a component of infiltrating glioma is often associated with focal neuronal elements. The latter is biologically interesting but of uncertain clinical significance. Oligodendrogliomas and glioneuronal tumors both illustrate the importance of effective communication between the pathologist and the treating oncologist in the discussion of these patients. Finally, the discussion of primitive pediatric tumors stresses the clinical importance of the distinction between different entities, like atypical teratoid rhabdoid tumor, "central" (supratentorial) primitive neuroectodermal tumor, "peripheral" primitive neuroectodermal tumor, and medulloblastoma. In medulloblastomas, the recognition of different variants is emerging as a prognostic factor that may in the future also predict therapy responsiveness.
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Affiliation(s)
- Peter Pytel
- Department of Pathology, University of Chicago Medical Center, Chicago, Illinois 60637, USA.
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Mimeault M, Batra SK. Recent advances in the development of novel anti-cancer drugs targeting cancer stem/progenitor cells. Drug Dev Res 2008. [DOI: 10.1002/ddr.20273] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Buccoliero AM, Castiglione F, Rossi Degl'Innocenti D, Paglierani M, Maio V, Gheri CF, Garbini F, Moncini D, Taddei A, Sardi I, Sanzo M, Giordano F, Mussa F, Genitori L, Taddei GL. O6-Methylguanine-DNA-methyltransferase in recurring anaplastic ependymomas: PCR and immunohistochemistry. J Chemother 2008; 20:263-8. [PMID: 18467255 DOI: 10.1179/joc.2008.20.2.263] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Ependymomas are the third most common brain tumor in children. The post surgical management is controversial. There are no convincing data on an effective role for chemotherapy. O(6)-Methylguanine-DNA-Methyltransferase (MGMT) is a DNA repair protein considered to be a chemosensitivity predictor. Hypermethylation of the MGMT gene promoter is an important cause of MGMT inactivation. We evaluated the MGMT gene promoter methylation and the immunohistochemical MGMT protein expression in 12 recurrent anaplastic ependymomas affecting children. Our purpose was to investigate the molecular rationale of the administration of alkylating agents to children affected by recurrent anaplastic ependymomas. All ependymomas lacked MGMT promoter hypermethylation and 9 (75%) showed high MGMT protein expression (>50% tumoral cells). Differences between different recurrences in the same patient were not observed. These results may indicate MGMT as a factor of chemoresistance to alkylating drugs in anaplastic ependymomas and support the uncertainties regarding the actual benefit of chemotherapy for patients with anaplastic ependymomas.
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Affiliation(s)
- A M Buccoliero
- Department of Human Pathology and Oncology, University of Florence, Florence, Italy.
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Juillerat-Jeanneret L, Bernasconi CC, Bricod C, Gros S, Trepey S, Benhattar J, Janzer RC. Heterogeneity of human glioblastoma: glutathione-S-transferase and methylguanine-methyltransferase. Cancer Invest 2008; 26:597-609. [PMID: 18584351 DOI: 10.1080/07357900802072913] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The DNA repair and detoxifying enzymes, O(6)-methylguanine-DNA-methyltransferase (MGMT) and glutathione-S-transferase (GST), may be responsible fpr poor response to alkylating agents in glioblastoma treatment. The methylation of MGMT promoter and the expression of MGMT and GST were highly heterogeneous in surgical specimens of human glioblastoma and in established human glioblastoma cells under 2-D and 3-D culture conditions, suggesting an intrinsic property of these cells. MGMT and GST expression did not predict the sensitivity of glioblastoma cells to alkylating agents. Combination of alkylating agents with inhibitors of GST disclosed additive effects, suggesting that inhibition of GST should be considered in glioblastoma therapy.
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Rapp M, Maurizis JC, Papon J, Labarre P, Wu TD, Croisy A, Guerquin-Kern JL, Madelmont JC, Mounetou E. A New O6-Alkylguanine-DNA Alkyltransferase Inhibitor Associated with a Nitrosourea (Cystemustine) Validates a Strategy of Melanoma-Targeted Therapy in Murine B16 and Human-Resistant M4Beu Melanoma Xenograft Models. J Pharmacol Exp Ther 2008; 326:171-7. [DOI: 10.1124/jpet.108.137737] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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