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PubMed1993

[Treatment results of intra-arterial ACNU infusion chemotherapy for primary cerebral malignant lymphoma].

From May, 1987 to January, 1991, eight patients harboring primary cerebral malignant lymphoma (primary, six cases; recurrent, two cases) were treated by intra-arterial ACNU infusion chemotherapy. All but two cases also had hyperosmotic blood brain barrier (BBB) modification. Six primary cases had conventional teletherapy of 46-58.7 Gy (average 54.1 Gy) and one recurrent case had been irradiated again by 18 Gy. The follow-up period was 3 to 67.5 months (average 21.4 months). In six cases demonstrating measurable tumors on diagnostic images, all showed a complete response. The 1- and 2-year survival time was 50.0% and 37.5%, respectively, with a median survival time of 13.0 months. These were somewhat better than our previous results, but not better than those in the literature. Although intra-arterial ACNU infusion chemotherapy with BBB modification was not considered superior to other chemotherapy regimens, it yielded some long-surviving cases. Hence this chemotherapy is still worth using for treatment of primary cerebral malignant lymphoma.

Adult↗
PubMed1995

[Modulation of the antitumor activity of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosoure a by O(6)-methyl-2'-deoxyguanosine--a new inhibitor of O(6)-alkylguanine-DNA-alkyltransferase].

O6-Methyl-2'-deoxyguanosine (O6-MedG), a novel inhibitor of O6-alkylguanine-DNA alkyltransferase (O6-AGT), has been synthesized. The ability of O6-MedG to deplete the O6-AGT activity in leukemia L1210 and melanoma B16 cells in vivo has been studied. After intraperitoneal administration of O6-MedG to mice bearing leukemia L1210 or melanoma B16, the activity of O6-AGT in tumour cells decreased by 50%. Pretreatment of leukemia L1210 bearing mice with O6-MedG (200 mg/kg) 24 hours prior to ACNU (15 mg/kg) administration resulted in six out of seven 60-day survivors. Treatment of mice with ACNU (15 mg/kg) alone increased the life span by 200%. Treatment of melanoma B16 bearing mice with O6-MedG and 3 hours thereafter with ACNU resulted in a 50% inhibition of tumour growth, whereas the inhibiting effect of ACNU alone was 16%. There was no difference in leukemia growth when L1210/BCNU bearing mice were treated with O6-MedG followed by ACNU treatment. In vivo ACNU (15 mg/kg) produced a deep and prolonged inhibition of DNA, RNA and protein synthesis in leukemia L1210 cells. The DNA synthesis in leukemia L1210/BCNU cells was shown to recover more rapidly than in L1210 cells. The activities of DNA-polymerases alpha and beta and, especially, of O6-AGT were elevated in ACNU-resistant leukemia cells as compared with ACNU-sensitive cells. The activation of some repairing enzymes, such as O6-AGT, DNA-polymerases alpha and beta as well as increased levels of GSH may play a role in the development of drug resistance to ACNU.

Animals↗
PubMedDate not supplied

In vitro assessment for neurotoxicity of antitumor agents before local administration into central nervous system.

In vitro assays for neurotoxicity with the aid of cultured mouse fetal neurons and glial cells were applied to investigate neurotoxicity of recombinant murine interferon-beta (rMuIFN-beta). These data were compared with those for MTX, ADR, and ACNU. The range of concentrations of the drugs used in these experiments spanned their clinically achievable concentrations in patient serum (IFN-beta: 1 x 10(4) IU/ml, MTX: 100 micrograms/ml, ADR: 20 micrograms/ml, ACNU: 20 micrograms/ml). rMuIFN- beta damaged both neurons and glial cells at concentrations of more than 1 x 10(5) IU/ml but did not damage them at 1 x 10(4) IU/ml or less. Microtubule-associated protein 1A (MAP1A) staining was decreased in rMuIFN-beta-treated (more than 1 x 10(5) IU/ml) neutrons. In conclusion, since IFN-beta may have some neurotoxic effects at concentrations higher than 1 x 10(5) IU/ml, it should be administered carefully, as should other antitumor agents, into the tumor cavity in the CNS following surgery.

Animals↗
PubMed1995

[Flow cytometric analysis of cell cycle for the action mechanism of antineoplastic agents].

Cell kinetics of cancers have been described in books, texts and other reports, but the correlation with action mechanism of antineoplastic agents has rarely been mentioned in the literature. The action mechanism of the antineoplastic agents such as interferon, ACNU and cisplatin was analyzed with use of propidium iodide and BrdU double staining by flow cytometer. Interferon showed S phase accumulation, ACNU and cisplatin blocked the stage of G(2)M phase. Flow cytometry was useful for the analysis of cell kinetics.

Antineoplastic Agents↗
PubMed1995

[Chemosensitivity of cultured meningiomas].

Meningioma is one of the popular benign brain tumors. However, the recurrence of this tumor is not infrequently encountered. In an attempt to establish the useful adjuvant therapy for the recurrent meningioma, in vitro chemosensitivity study for meningioma was conducted. Among various chemotherapeutic agents tested here, cisplatin showed highest cytotoxicity on cultured meningioma cells. In conclusion, cisplatin may be useful in adjuvant chemotherapy for the recurrent meningioma.

Antineoplastic Agents↗
PubMedDate not supplied

Superselective angio-CT of brain tumors.

PURPOSE: To determine the efficacy of superselective angio-CT in the diagnosis of astrocytoma. METHODS: Nineteen patients with astrocytoma had superselective angio-CT before chemotherapeutic agents were administered via superselective intraarterial infusion. CT was performed after contrast material was delivered through a microcatheter, which had been advanced into the feeding arteries of the tumor. Superselective angio-CT scans were compared with digital subtraction angiograms, conventional contrast-enhanced CT scans, and contrast-enhanced T1-weighted MR images. RESULTS: Superselective angio-CT scans depicted contrast enhancement of the tumor in all of the patients and the medullary veins of the tumors in 32% of the patients. Digital subtraction angiograms showed tumor stains in 68% of the patients and the medullary veins in only 5%. Conventional CT scans and MR images showed contrast enhancement of the tumor in 89% of the patients. Superselective angio-CT scans confirmed the proper position of the catheter tip for the infusion of a chemotherapeutic agent. CONCLUSIONS: Superselective angio-CT can be used to depict contrast enhancement of tumors and the vascular structures that are characteristic of astrocytomas.

Adult↗
PubMed1997

[Treatment of malignant melanoma: recent advances and perspectives].

Because malignant melanoma is a highly malignant neoplasm, correct diagnosis and appropriate treatment are essential to improve the prognosis. In the present paper the author summarizes the advancements in the therapy of malignant melanoma, reviewing papers recently published in this field. It is noteworthy that a narrow excision margin has been recommended even for the surgery of this neoplasm. This narrow margin has been approved by the prospective randomized trial performed by the WHO melanoma study group. The study group also confirmed that elective lymph node dissection is not significant in the improvement of the prognosis, when compared to the delayed lymph node dissection. Considering these findings, the author proposes a revised guideline for the treatment of malignant melanoma according to UICC stages. A brief comment is made on a new drug, fotemustine, that has an effect on brain metastases. In addition, high response rates obtained by the Dartmouth regimen (BCDT regimen), including tamoxifen, an estrogen antagonist, are reported. "Sequential" biochemoimmunotherapy based on a new concept of rational combination of chemotherapeutic and biologic agents seems highly effective against metastatic melanoma, showing more than 50% response rates. In the regimens, chemotherapy including CDDP is followed by administration of the cytokines, IL-2 and IFN-alpha. These regimens possibly induce specific and/or non-specific immune reactions against melanoma cells, which may contribute to the high response rates.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

[Study on potentiation of nitrosourea-cytotoxicity by DNA repair enzyme inhibitors in human brain tumor cells].

Nitrosoureas are antitumor alkylating agents widely used in the chemotherapy of malignant brain tumors. However, the effectiveness of adjuvant nitrosourea chemotherapy has proved inadequate, failing to provide any significant prolongation of survival time. One of the reasons for the poor results is a drug resistance system in the form of the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT). O6-alkylguanine derivatives are well known to be inhibitors of MGMT, and inactivation of MGMT by these derivatives leads to increased tumor cell sensitivity to nitrosoureas. In this study, the authors tested the ability of O6-benzylguanine, O6-(4-, 3- and 2-fluorobenzyl) guanines, O6-(4-, 3- and 2-trifluoromethylbenzyl) guanines, O6-(4-, 3- and 2-pyridylmethyl) guanines and O6-(2- and 1-naphthylmethyl) guanines to reduce MGMT activity in SF-188 cell-free extract by using [3H] methylated substrate DNA and analyzed their enhancing effect on the cytotoxicity of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl) -3-nitrosourea hydrochloride (ACNU) by using a calorimetric cytotoxicity assay. The MGMT activity in the SF-188 cell-free extract was 944 +/- 43 fmol/mg protein (Mean +/- SD, n = 5). O6-(4- and 3-fluorobenzyl) guanines were found to be more effective in inactivating MGMT than O6-benzylguanine. O6-(4-trifluoromethylbenzyl) guanine considerably reduced MGMT activity as did O6-benzylguanine. O6-(3-trifluoromethylbenzyl) guanine, O6-(4- and 3-pyridylmethyl) guanines, and O6-(2-naphthylmethyl) guanine were intermediately effective, but O6-(2-fluorobenzyl) guanine, O6-(2-trifluoromethylbenzyl) guanine and O6-(1-naphthylmethyl) guanine were less effective. ACNU cytotoxicity in SF-188 cells was strongly enhanced by pretreatment with O6-(4- and 3-fluorobenzyl) guanines and O6-(4-trifluoromethylbenzyl) guanine and moderately enhanced by O6-(3- trifluoromethylbenzyl) guanine and O6-(4- and 3-pyridylmethyl) guanines, but not enhanced by O6-(2-fluorobenzyl) guanine, O6-(2-trifluoromethylbenzyl) guanine and O6-(1-naphthylmethyl) guanine. The test compounds were not cytotoxic at concentrations between 0.5 and 5.0 microM. The enhancing effects on ACNU cytotoxicity were consistent with the inhibition of MGMT activity after two-hour pretreatment with O6-arylmethylguanine derivatives. These results indicate that the 2-position of the O6-benzyl group plays an important role in the inactivation of the MGMT activity and the potentiation of ACNU cytotoxicity.

Antineoplastic Agents↗
PubMedDate not supplied

Transformation of human glioma cell lines with the p16 gene inhibits cell proliferation.

We examined the genomic status of the p16 gene in 5 human glioma cell lines by Southern blot analysis. The p16 gene was located in the 9p21 chromosomal region and homozygous deletion was detected in 4 of 5 (80%) human glioma cell lines and 5 of 15 (33%) clinical samples. We transfected the full-length human p16 gene into p16-null human glioma cell line, U251MG cells, using the plasmid vector pRc/CMV-p16 and evaluated the effect of p16 gene transfer on the growth suppression of malignant glioma cells. The transfection of p16 cDNA caused growth suppression through G1 cell cycle arrest in U251MG cells. We also examined the effect of p16 gene transfer on the chemosensitivity to cis-diamminedichloroplatinum II (CDDP), 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl) -3-nitrosourea hydrochloride (ACNU), and 5'-azacytidine (AZC). We did not detect any change in them after p16 gene transfer. These results might suggest that deletion of p16 genes promoted unrestrained growth in human glioma but has no relationship to the chemosensitivity to CDDP, ACNU and AZC.

Antineoplastic Agents↗
PubMed1997

Intrathecal ACNU against experimental leptomeningeal tumors.

Therapeutic efficacy and cell kinetics of intrathecal ACNU, 3-(4-amino-2-methyl-5-pyrimidinyl) methyl-1-(2-chloroethyl)-1-nitrosourea, were investigated in experimental meningeal carcinomatosis rats. Therapeutic effect of intrathecal ACNU (IT ACNU) against meningeal carcinomatosis model was evaluated in rats induced by intracisternal inoculation of Walker 256 carcinosarcoma cells. The median survival time of the rats treated with IT ACNU 1.5 mg/kg on day 5 after tumor inoculation was significantly increased by 145% as compared with that of non-treatment rats. The cell kinetics was studied immunohistochemically using indirect immunoperoxidase method with bromodeoxyuridine (BrdU) and anti-BrdU monoclonal antibody (Becton-Dickinson). The meningeal carcinomatosis rats were treated with IT ACNU (1.5 mg/kg) on the fifth day after tumor inoculation. Before and 12, 24, 48, 96 or 144 hours after treatment, the rats received intravenous BrdU (200 mg/kg) injection. Thirty minutes later, the rats were sacrificed and the brains were removed. Brain sections were stained immunohistochemically with anti-BrdU monoclonal antibody. Labeling index (LI) which represented the percentage of tumor cells in synthetic phase was obtained by counting immunoreactive cells under the microscope. Before treatment, LI was around 34% on day 5 after tumor inoculation and dropped to below 20% 12 to 48 hours after IT ACNU. However, it increased to around 36% on day 4 after IT ACNU. The antineoplastic effect of IT ACNU against meningeal carcinomatosis rats might be expected in the early stage of intrathecal administration.

Animals↗
PubMed1997

[Chemoradiation for rectal cancer].

Based on the results of the Study Group for Surgical Adjuvant Radiochemotherapy for Rectal Cancer and the Study Group for Surgical Therapy and Combined Irradiation in Rectal Cancer, we examined the clinical aspects of the relatively new field of chemoradiation for rectal cancer and examined improvements in the therapeutic results. Furthermore, we examined the future outlook with particular regard to selection of therapeutic drugs and autonomic nerve preserving operation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Transient induction of the MRP/GS-X pump and gamma-glutamylcysteine synthetase by 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3- nitrosourea in human glioma cells.

Treatment of human glioma A172 cells with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU), an alkylating antitumor agent the primary target of which has been thought to be DNA, resulted in elevated expression of mRNA for multidrug resistance-associated protein (MRP) within the first 2 h and then a decrease in expression 24 h after the treatment. Western blot analyses revealed that levels of MRP in these ACNU-treated cells paralleled mRNA levels. Membrane vesicles prepared from ACNU-treated cells also displayed elevated transport activities for leukotriene C4, a known substrate for MRP. Gamma-glutamylcysteine synthetase (gamma-GCS) mRNA expression was coinduced with MRP by ACNU. Because gamma-GCS is the rate-limiting enzyme involved in the de novo biosynthesis of glutathione, increases in glutathione were also transiently induced by ACNU. These results demonstrate for the first time that the expression of functional MRP and gamma-GCS can be transiently coinduced by ACNU. Multiple short exposures (1 h) of ACNU following a long duration (1 week) of drug-free conditions resulted in the development of an ACNU-resistant population (designated A172R) that overexpressed MRP/gamma-GCS mRNA and had elevated transport activities for leukotriene C4. A172R exhibited cross-resistance to the antitumor drug doxorubicin and heavy metal sodium arsenate but not to cisplatin. Our results also demonstrate that intermittent treatments of human glioma cells with ACNU can lead to the development of MRP-related multidrug resistance. These results, taken together, reveal a possible new mechanism of the development of drug resistance for the antitumor nitrosoureas.

ATP-Binding Cassette Transporters↗
PubMed1997

[Comprehensive therapy of malignant glioma of the brain].

The paper deals with the results of therapy of malignant glioma of the brain using a complex of procedures (surgical removal, nidran chemotherapy and telegammatherapy (1991-1997). Therapy and follow-up lasted 2-64 months. Mean survival after treatment was 16 months; 63% survived more than 24 months; post-operative mortality was 2.4%.

Adolescent↗
PubMed1998

[Evaluation of brain tumor by 99mTc-MIBI: comparison study with 201Tl and predictivity of therapeutic effect].

We compared the detectability of 99mTc-MIBI and 201Tl-chloride for brain tumor in relationship with histopathology. We also evaluated correlation between therapeutic effect using ACNU, Cisplatine and the degree of MIBI tumor uptake. The subjects were 31 brain tumor histologically confirmed by operation or biopsy. Dual-isotope SPECT technique was performed at both 20 min and 180 min after tracer injection. A tumor to normal lung ratio on both early (ER) and delayed image (DR) and retention index (RI) were calculated. The positive rates of 99mTc-MIBI (90.3% and 77.4%) were comparable to that of 201Tl (90.3% and 80.6%). In the relationship with histopathology, both MIBI and Tl accumulated in 100% of glioblastoma (GBM), metastasis (meta), anaplastic astrocytoma and 25% of low grade astrocytoma on both early and delayed images. On semiquantitative analysis, there were no statistical significance among GBM, meta and anaplastic astrocytoma of ER, DR, RI in the both radiopharmaceuticals. However, both ER and DR in GBM tended to be higher than those of anaplastic astrocytoma. In spite of intense MIBI uptake, GBM patients died within six months except one patient. We concluded that MIBI can be helpful in detecting brain tumor as Tl. MIBI also might be useful in estimating the degree of malignancy in glioma. However, intense MIBI uptake did not mean favorable therapeutic effect in patients with GBM treated with ACNU and Cisplatine.

Adult↗
PubMed1998

[Clinical evaluation of intraoperative radiotherapy using photon radiosurgery system for brain tumors].

The photon radiosurgery system is a miniature X-ray generator that can be placed stereotactically and intraoperatively into intracranial tumors to deliver a single fraction of high-dose interstitial irradiation. This battery-powered device produces low energy X-ray photons in a spherical and symmetrical pattern at the probe tip. Dose rates of up to 200 cGy/Mim are possible, allowing for the administration of 15 Gy to a lesion 3 cm in diameter in less than 1 hr. Background exposure is minimal, and no special shielding of the patient or health care personnel is required. Thirty-nine patients with brain tumor were treated in this method. There were no adverse effects. During the follow-up period of 1-30 months, 3 cases with 5 metastatic brain tumors died about 8 months after this treatment. Five recurrent cases of 21 malignant gliomas died about 4 months after treatment. Interstitial radiotherapy using photon the radiosurgery system promises to be a useful treatment for brain tumors.

Aged↗
PubMed1998

Changes in immunological parameters after combination adjuvant therapy with intravenous DTIC, ACNU, and VCR, and local injection of IFN-beta (DAV + IFN-beta therapy) into malignant melanoma.

Combination adjuvant therapy with intravenous dimethyl triazeno imidazole carboxamide (DTIC), 1-[4-amino-2-methyl-5-pyrimidinyl]-methyl-3-[2-chloroethyl]-3-nitrosoure a hydrochloride (ACNU) and vincristine (VCR) and local injection of interferon-beta (IFN-beta) (DAV + IFN-beta therapy) has been widely applied to treat malignant melanoma, and its therapeutic effect is accepted in Japan. Natural killer (NK) activity, CD4+ and CD8+ T cell counts, CD4/CD8 ratio, and white blood cell counts were analyzed before and after DAV + IFN-beta therapy in order to validate its efficacy. After DAV + IFN-beta therapy, the CD4/CD8 ratio was elevated; however, numbers of both CD4+ and CD8+ T cells and NK activity were consecutively depressed. Peripheral lymphocytes were also decreased, possibly by myelosuppression due to the DAV therapy. The posttreatment suppression of NK activity appeared in spite of the administration of IFN-beta. It is suggested that a more effective adjuvant immunomodulator should be introduced to improve the therapeutic effect of the combination adjuvant chemotherapy in malignant melanoma.

Adult↗
PubMed1997

Retroviral coexpression of two different types of drug resistance genes to protect normal cells from combination chemotherapy.

Drug resistance genes can protect normal hematopoietic cells from the toxicity of anticancer agents. Because chemotherapeutic agents are often used in combination in current clinical protocols, coexpression of two different drug resistance genes should be useful in protecting normal bone marrow cells from the hematotoxicities caused by combination chemotherapy. In this study, we have combined the human multidrug resistance gene (MDR1) and human O6-methylguanine DNA methyltransferase (MGMT) gene as drug resistance genes. For the coexpression of two drug resistance genes, we have constructed two bicistronic retrovirus vectors. One vector is Ha-MDR-IRES-MGMT, in which translation of the MDR1 cDNA is cap-dependent and MGMT translation is dependent on an internal ribosome entry site (IRES). The other is Ha-MGMT-IRES-MDR, which has cap-dependent MGMT translation and IRES-dependent MDR1 translation. MGMT-negative HeLa derivative (MR) cells transduced with these retroviruses showed resistance to vincristine (from MDR1) and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosou rea (ACN; from MGMT). Cells transduced with Ha-MDR-IRES-MGMT showed higher resistance to vincristine and lower resistance to ACNU than those transduced with Ha-MGMT-IRES-MDR. In any case, the resistance levels of cells transduced with either vector were high enough to select transduced cells with vincristine or ACNU. The expression levels of P-glycoprotein or MGMT in the transduced cells determined by FACS and Western blot analysis correlated well with the extent of resistance to vincristine and ACNU, respectively. All of the MGMT-transduced cells expressed higher amounts of MGMT than the MGMT-expressing parental cell line HeLa S3. Murine bone marrow cells transduced with Ha-MDR-IRES-MGMT and selected with vincristine also showed simultaneous resistance to vincristine and ACNU. These results suggest that bicistronic retroviral vectors allow the functional coexpression of two different types of drug resistance genes. This strategy could be applicable to any combination of drug resistance genes.

3T3 Cells↗