Results of Three Consecutive Combined Treatments for Malignant Gliomas

Arcicasa, M.; Roncadin, M.; Bortolus, Roberto; Bassignano, G.; Boz, G.; Franchin, Giovanni; Paoli, A. De; Trovò, Marco

doi:10.1097/00000421-199410000-00017

Cited by 8 publications

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“…[1][2][3][4] Over the past decade, novel treatment approaches utilizing virus-based gene therapeutic vectors have become a topic of intense study worldwide. A prominent strategy advanced to the stage of clinical trials involves the delivery of 'suicide genes' such as the herpes simplex virus thymidine kinase (HSVtk) or Escherichia coli cytosine deaminase (CD) genes whose products have the ability to convert largely harmless prodrugs into potent inhibitors of DNA synthesis.…”

Section: Introductionmentioning

confidence: 99%

Double suicide gene therapy using a replication defective herpes simplex virus vector reveals reciprocal interference in a malignant glioma model

et al. 2002

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Section: Introductionmentioning

confidence: 99%

Double suicide gene therapy using a replication defective herpes simplex virus vector reveals reciprocal interference in a malignant glioma model

et al. 2002

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“…8,9 Individualization of glioma therapy is recommended. We carried out a new adjuvant therapy that was individualized based on the results of the reverse transcription-polymerase chain reaction (RT-PCR) for MGMT to treat malignant gliomas.…”

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confidence: 99%

O⁶‐methylguanine‐DNA methyltranspherase gene expression in gliomas by means of real‐time quantitative RT‐PCR and clinical response to nitrosoureas

Tanaka

Kobayashi

Utsuki

et al. 2002

Intl Journal of Cancer

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Key words: MGMT; real-time RT-PCR; ACNU; gliomaNitrosoureas are alkylating agents that cause cell death by binding to DNA. Among nitrosoureas, 1-(4-amino-2-methyl-5-pyrimidynyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) is widely used in Japan to treat gliomas because of its ability to permeate the blood-brain-barrier and excellent clinical effects in combination with radiation and interferon (IFN)-␤. [1][2][3] Drug-resistance genes are some of the most important elements of tumors themselves in determining drug-resistance, 4 and O 6 -methylguanine-DNA methyltransferase (MGMT) is a drug-resistance gene for nitrosoureas. 5,6 The cross-linking of doublestranded DNA by alkylating agents is inhibited by the cellular DNA-repair protein MGMT. MGMT rapidly reverses alkylation at the O 6 position of guanine, thereby averting lethal cross-linking. 7 This is the mechanism by which MGMT induces resistance to alkylating agents such as ACNU.Protocol studies for malignant gliomas have not provided encouraging therapeutic results because of the heterogeneity and various drug-sensitivities of the tumors. 8,9 Individualization of glioma therapy is recommended. We carried out a new adjuvant therapy that was individualized based on the results of the reverse transcription-polymerase chain reaction (RT-PCR) for MGMT to treat malignant gliomas. 2 Our preliminary individual adjuvant therapies (IAT) based on RT-PCR results regarding MGMT expression seemed to be more effective than conventional therapies for malignant gliomas.The level of MGMT varies widely according to the type of tumor, and even varies among tumors of the same histological classification. 5,10 Approximately 30 -50% of gliomas lack MGMT. 11 The fact that more than 50% of gliomas express MGMT limits the indications for ACNU. In our preliminary IAT, platinum (Pt)-compounds were used instead of ACNU even though Ptcompounds had not been accepted as being effective in gliomas. 12,13 To ensure IAT for gliomas, quantitative evaluation is needed for a higher initial response and prolongation of survival.We carried out the present study to determine more appropriate indications for the use of ACNU in gliomas. Real-time quantitative RT-PCR was used to re-evaluate the treated gliomas. MATERIAL AND METHODS Real-time quantitative RT-PCRIn 100 frozen sample of neuroepithelial tumors (19 low-grade neuroepithelial tumors, 28 Grade III gliomas, 41 glioblastomas, and 12 medulloblastomas), MGMT was quantitated by real-time quantitative RT-PCR using SYBR Green dye. RT-PCR was basically carried out as described previously. 14 -16 Briefly, total RNA was extracted from frozen tissue specimens weighing about 1 g, which had been homogenized using a glass Teflon homogenizer, via the guanidinium thiocyanate-phenol-chloroform single-step extraction method with Isogen (Nippon Gene, Toyama, Japan). 17 After ethanol precipitation, about 100 g of total RNA was extracted. Forty microliters of complementary deoxyribonucleic acid (cDNA) solution was synthesized from 2 g of total RNA wi...

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“…Protocol studies for malignant gliomas have not provided encouraging therapeutic results because of the heterogeneity and various drug-sensitivities of the tumors (Arcicasa et al, 1994). Individualization of glioma therapy is recommended.…”

Section: Introductionmentioning

confidence: 99%

Quantitation of O6-Methylguanine-DNA Methyltransferase Gene Messenger RNA in Gliomas by Means of Real-Time RT-PCR and Clinical Response to Nitrosoureas

et al. 2005

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1. O6-methylguanine-DNA methyltransferase (MGMT) mRNA was measured in 50 malignant gliomas that had received 1-(4-amino-2-methyl-5-pyrimidynyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) after the resection of the tumor by real-time reverse transcription-polymerase chain reaction (RT-PCR) using TaqMan probe. 2. The mean absolute value of MGMTmRNA normalized to the level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) for 50 tumors was 1.29 x 10(4)+/- 1.28 x 10(4) copy/microg RNA (mean +/- SD). The amount of MGMTmRNA less than 6 x 10(3) copy/microg RNA was the most significant factor in predicting the initial effect of treatment with ACNU by multi-variant regression analysis (p = 0.0157). 3. These results suggest that quantitation of MGMTmRNA is the excellent method for predicting for the effect of ACNU in glioma therapy.

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Results of Three Consecutive Combined Treatments for Malignant Gliomas

Cited by 8 publications

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Double suicide gene therapy using a replication defective herpes simplex virus vector reveals reciprocal interference in a malignant glioma model

Double suicide gene therapy using a replication defective herpes simplex virus vector reveals reciprocal interference in a malignant glioma model

O⁶‐methylguanine‐DNA methyltranspherase gene expression in gliomas by means of real‐time quantitative RT‐PCR and clinical response to nitrosoureas

Quantitation of O6-Methylguanine-DNA Methyltransferase Gene Messenger RNA in Gliomas by Means of Real-Time RT-PCR and Clinical Response to Nitrosoureas

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Results of Three Consecutive Combined Treatments for Malignant Gliomas

Cited by 8 publications

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Double suicide gene therapy using a replication defective herpes simplex virus vector reveals reciprocal interference in a malignant glioma model

Double suicide gene therapy using a replication defective herpes simplex virus vector reveals reciprocal interference in a malignant glioma model

O6‐methylguanine‐DNA methyltranspherase gene expression in gliomas by means of real‐time quantitative RT‐PCR and clinical response to nitrosoureas

Quantitation of O6-Methylguanine-DNA Methyltransferase Gene Messenger RNA in Gliomas by Means of Real-Time RT-PCR and Clinical Response to Nitrosoureas

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O⁶‐methylguanine‐DNA methyltranspherase gene expression in gliomas by means of real‐time quantitative RT‐PCR and clinical response to nitrosoureas