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Significance of DNA cross-links on 1-(4-amino-2-methylpyrimidin-5-yl)methyl-3-(2-chloroethyl)-3- nitrosourea (ACNU)-induced cytotoxicity against ACNU-sensitive and -resistant lines of 9L rat glioma cells.

The formation and removal of DNA cross-links caused by treatment with 1-(4-amino-2-methylpyrimidin-5-yl)-methyl-3-(2-chloroethyl)-3-nitr osourea (ACNU) were assayed by the technique of alkaline elution for DNA in comparison with the cytotoxicities in ACNU-sensitive rat 9L cells or ACNU-resistant subclones of 9L cells (9L/R cells). The ACNU-resistant 9L/R cells appeared to be about 16 times more resistant against ACNU than were the 9L cells. The DNA cross-links immediately after the treatment with ACNU were not detectable in 9L or 9L/R cells. Although the level of cross-links for 9L cells had reached a maximum at 6 hours and then persisted at almost the same level as that at 24 hours after the treatment with ACNU, the level for 9L/R cells was very low at 6 hours and then gradually decreased at 24 hours after treatment with ACNU. Inhibition of the formation of DNA interstrand cross-links caused by the treatment with ACNU might be a factor for the ACNU resistance in 9L/R cells. Also, the capacity for the repair of DNA interstrand cross-links might participate in the mechanisms of the ACNU resistance in 9L/R cells.

Animals↗

[Overcoming of ACNU resistance in an ACNU-resistant subline of rat C6 glioma in vivo through enhanced effect of ACNU by calmodulin inhibitor].

A calmodulin inhibitor, trifluoperazine, was found to enhance the cytotoxic action of ACNU in C6, especially in ACNU-resistant (C6/ACNU) glioma cells in vitro. In order to clarify the efficacy of trifluoperazine in vivo, 1 X 10(7) C6 or C6/ACNU cells were percutaneously implanted into the cisterna magna of Wistar rats to produce meningeal gliomatosis (MG) models as a chemosensitivity assay system. MG rats were treated with ACNU and trifluoperazine according to a variety of schedules. Trifluoperazine in doses of 250 to 500 micrograms/kg intrathecally (it) administered with 1 mg/kg ACNU 1 day after the tumor inoculation significantly increased the life span of the C6/ACNU bearing (C6/ACNU MG) rats. At doses of 250 and 500 micrograms/kg of trifluoperazine in the C6/ACNU MG rats, values of increased life span of 22 and 30% were obtained with a 1 mg/kg dose of ACNU, respectively. These values were statistically significant compared with that obtained in the C6/ACNU MG rats treated with ACNU alone at 1 mg/kg. It might be concluded that the combination chemotherapy with ACNU and such a calmodulin inhibitor as trifluoperazine could overcome ACNU resistance in malignant brain tumors.

Animals↗

[Assessment of functional status in children with brain tumors].

Thirty children treated for brain tumors between 1978-1985 at Kurume university hospital were evaluated for alternation in intellectual, emotional, and social function. They were 15 males and 15 females, aged 3 to 16 years, on the averaged 1.7 years after treatment. Twenty-eight children had no neurological deficits and 2 children had slight neurological deficits. It was possible for twenty-eight children to be evaluated for intelligence quotient by Wechsler Intelligence Scale for Children-revised and Tanaka-Binet. The median score and standard deviation of intelligence quotient (IQ) test in children with brain tumors were as follows; verbal IQ: 84 +/- 16, performance IQ: 77 +/- 20, full scale IQ: 80 +/- 20. There children with brain tumors obtained significant low IQ scores than children (t-test, P less than 0.01). Twenty-one (72%) children showed subnormal IQ scores (IQ less than 90) and 7 children showed normal IQ scores (IQ greater than or equal to 90). Concerning social and emotional function, twelve children (45.7%) showed abnormal behaviour. The median scores and standard deviation of IQ scores in cranial irradiated patients were as follows; verbal IQ: 79 +/- 13, performance IQ: 71 +/- 15, full scale IQ: 71 +/- 14. Especially, ten of twelve cranial irradiated patients showed subnormal IQ scores. Also, cranial irradiated patients obtained significant low IQ scores than non-cranial irradiated patients (t-test, P less than 0.05). Serial evaluation of three cranial irradiated patients revealed further deterioration without recurrence of tumor and hydrocephalus, The results are discussed to: (1) the effects and mechanism of cranial irradiation on cognitive development.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Strategy of cancer treatment using human recombinant interleukin 2 and lymphokine activated killer cells].

There are two strategies for evaluating the antitumor effect of IL-2. In the first approach IL-2 has been used to support the proliferation of T-effector cells or LAK cells in vitro in the hope that large quantities of these effector cells can be used therapeutically. This approach has shown some efficacy in animal models if LAK cells are administered in combination with IL-2. However, it is extremely difficult to standardize the numbers of lymphocytes and the biological activity of effector cells for clinical use. Recently the cloning of IL-2 has made available large quantities of purified recombinant IL-2 (rIL-2) for preclinical and clinical trials. Accordingly there have been recent attempts at injecting rIL-2 directly to stimulate effector cells in vivo. In this study, in vivo and in vitro augmentation of the cytotoxicity of spleen lymphocytes against syngeneic B-16 melanoma cells (induction of LAK cells) and the suppression of artificial pulmonary and liver metastases of B-16 melanoma in C57BL/6 mice was tried by subcutaneous multiple injections of high-dose human rIL-2. In addition, the immunosuppressive effect of a water-soluble nitrosourea derivative (ACNU) was determined in terms of the cytotoxicity of spleen lymphocytes, and the restoring effect of lymphokine-activated killer (LAK) cells and/or human recombinant interleukin-2 (rIL-2) on the cytotoxicities of spleen lymphocytes were examined in ACNU-treated C57 BL/6 mice. It was also tested whether the administration of LAK cells and/or rIL-2 could reduce the increased numbers of pulmonary metastases in ACNU-treated mice. The cytotoxicity of spleen lymphocytes against YAC-1 cells as well as against syngeneic B-16 and F-10 melanoma cells was augmented not only by incubation of spleen lymphocytes with human recombinant interleukin-2 (rIL-2) in vitro but also by injecting high-dose rIL-2 into C57BL/6 mice for more than 3 consecutive days. In animals injected with multiple high doses of rIL-2 subcutaneously, the numbers of tumor nodules in the lung were significantly decreased 21 days after intravenous tumor inoculation. In addition, in these groups of animals no liver metastases were observed although liver metastases were detected in 6/11 of control mice. The maximum effective dose of ACNU suppressed the cytotoxicity of spleen lymphocytes and pretreatment with ACNU enhanced the induction of artificial pulmonary metastases.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Involvement of cytotoxic T-lymphocytes in the antitumor activity of spergualin against L1210 cells.

Spergualin exhibited a strong antitumor effect against L1210(IMC), a tumor cell line which has been maintained in BALB/c X DBA/2 F1 (hereafter called CD2F1) mice in the Institute of Microbial Chemistry. Mice inoculated i.p. with 10(5) cells of L1210(IMC) survived more than 60 days by daily i.p. administration of spergualin for 9 days at 5 mg/kg/day, which was started 1 day after the tumor inoculation. These cured mice rejected a second inoculation of 10(6) cells of L1210(IMC), but they did not reject the inoculation of 10(2) P388 cells. In Winn's tumor neutralization assay and in the 51Cr release assay, the T-cell fraction prepared from the spleens of the cured mice had higher cytotoxic activity against L1210(IMC) than whole spleen cells. The cytotoxic activity of spleen cells was diminished by treatment with anti-Thy-1.2 or anti-Lyt-2.1 antibody and complement. Therefore, the effector cells involved in the immunological rejection should be regarded as cytotoxic T-lymphocytes. The cytotoxic activity of these T-lymphocytes was measured during and after the spergualin administration for 9 days, and high activity was observed from 1 day after the final spergualin administration. The antitumor effect of spergualin against L1210(IMC) was much lower in T-cell-deficient athymic mice. These results suggest that cytotoxic T-lymphocytes are involved in the antitumor action of spergualin against L1210(IMC) in vivo.

Animals↗

[Experimental studies on the treatment of recurrent gliomas].

For the purpose to study reasonable treatment for recurrent gliomas, in vitro immunochemosensitivity tests were performed by using human malignant glioma cell line (ONS-12) and its ACNU-resistant cell line (ONS-12/ACNU), which were established in our laboratory. ONS-12/ACNU cells showed a cross-resistance to Ara-C, but not for cisplatin and methotrexate. The lymphokine-activated killer (LAK) cells induced in vitro from the peripheral blood lymphocytes (PBL) of healthy subjects, showed stronger cytotoxicity to ONS-12/ACNU than ONS-12 cells. From these data, selection of appropriate anti-tumor agents on the in vitro sensitivity tests was a most useful method for the treatment of recurrent gliomas, and the adoptive immunotherapy with LAK cells may be useful for ACNU-resistant gliomas.

Antineoplastic Agents↗

[Combination therapy with HU IFN-beta and ACNU against malignant brain tumors, Part 1. Experimental study in vitro].

Augmentation of cytotoxicity against malignant glioma using a combination of Hu IFN-beta and ACNU was analyzed in vitro from the points of cell growth inhibition and alteration of the DNA histogram. Cytotoxicity was tested by exposing 13 human glioma cell lines to ACNU at a concentration of 5 micrograms/ml and/or Hu IFN-beta at a concentration of 10(3) IU/microliters. These concentrations were considered to be clinical doses. Additive or synergistic effects of the combination of the two agents were observed in all cell lines tested. The cytotoxic effect of two log kill was seen in two cell lines given ACNU treatment alone, one cell line treated with Hu IFN-beta alone, and nine treated with the combination. Flow-cytometry studies of the DNA histogram showed accumulation in the G2+M phase with ACNU and in the S phase with Hu IFN-beta. On the other hand, marked accumulation using the combination in the S phase followed by the G2+M phase was observed and this accumulation lasted for over a week. The present results show an augmentation of antitumor activity and suggest the effectiveness of combined Hu IFN-beta/ACNU therapy in the treatment of patients with malignant glioma.

Antineoplastic Agents↗

[Drug administration in combination for management of cancer].

The use of drugs in combination for the management of cancer patients aims at the increased therapeutic advantage by elimination the problem of the heterogeneous sensitivity of cancer cells to anticancer drugs, and by delaying or preventing the development of drug resistance within given tumors. Theoretically, the effects of drugs in combination are classified as antagonistic, subadditive, additive and synergistic. Since these results hold for both tumors and hosts, the effects of combined drugs should be considered in terms of therapeutic index. From this viewpoint, the choice and administration schedule of drugs in combination must be synergistic or additive for the tumors and antagonistic or subadditive for the hosts in regard to combined effects. Thus, the rationale for combined drug therapy should be considered from the aspects of biochemical basis, drug resistance, cytokinetic and pharmacologic rationales, and toxicologic basis.

Antineoplastic Combined Chemotherapy Protocols↗

[Regional blood flow of experimental brain tumors with special reference to effects of chemotherapy and radiotherapy].

Regional blood flow and capillary permeability in the experimental brain tumors and their surrounding brain tissue of rats were measured with quantitative 14C-antipyrine and 14C-alpha-aminoisobutyric acid (AIB) autoradiographic method. The pharmacokinetic implications with respect to drug delivery to tumor tissue and the effect of ionizing irradiation were discussed in these physiological measurement. A suspension of 1 X 10(4) rat glioma cells (E239 RG 12) was stereotactically implanted into the right basal ganglia of CD-Fisher rats, and spherical brain tumors developed 10-17 days after implantation with a diameter of 1--5 mm. Autoradiographic investigations were performed for rats with small tumors (1--2 mm in diameter) and large tumors (4--5 mm in diameter). The uniform blood flow (91.7 +/- 13.1 ml/100 g/min: mean +/- S.E.) was observed in small tumors with the patchy low flow area (56.7 +/- 12.5 ml/100 g/min) surrounding the tumor. In large tumors, the blood flow was markedly decreased in the central part of the tumor (28.3 +/- 2.4 ml/100 g/min) with a ring shaped high flow area in the peripheral part (59.3 +/- 5.9 ml/100 mg/min). The blood flow in the brain adjacent to the tumor (30.5 +/- 2.5 ml/100 g/min) was lower than that in the peripheral part of the tumor. The uptake of 14C-AIB was quite similar to that of 14C-antipyrine suggesting the smaller permeability in the central part of the tumor. Neuropathological studies did not reveal necrotic foci, but viable cells in these areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Investigation of resistance to DNA cross-linking agents in 9L cell lines with different sensitivities to chloroethylnitrosoureas.

The 9L-2, 9L-7, and 9L-8 cell lines, derived from the 9L in vivo rat brain tumor, were treated with nitrosoureas that can alkylate and cross-link DNA and carbamoylate intracellular molecules to various extents. Compared to 9L cells, 9L-2 cells were very resistant to the cytotoxic effects of 1,3-bis(2-chloroethyl)-1-nitrosourea, and to 2-[3-(2-chloroethyl)-3-nitrosoureido]-D-deoxyglucopyranose. The sensitivity of 9L-7 and 9L-8 cell lines to these drugs was intermediate between 9L and 9L-2. Treatment of 9L, 9L-2, 9L-7, and 9L-8 cell lines with 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea produced approximately the same level of cell kill. Compared to 9L cells, 9L-2 cells are 10-fold more resistant to the cytotoxic effects, 34-fold more resistant to the induction of sister chromatid exchanges, and have 40% fewer DNA interstrand cross-links caused by treatment with 3-(4-amino-2-methyl-5-pyrimidinyl)methyl-1-(2-chloroethyl)-1-nitrosourea . In contrast, treatment of 9L and 9L-2 cells with 1-ethylnitrosourea produced approximately the same level of cell kill and induction of sister chromatid exchanges. Our results suggest that the resistance of 9L-2, 9L-7, and 9L-8 cells is related to DNA cross-linking and not to alkylation or carbamoylation. We studied the effects of other agents that form DNA cross-links with structures different from those formed by treatment with chloroethylnitrosoureas (CENUs) in 9L and 9L-2 cells. In contrast to results obtained with CENUs, 9L-2 cells were 2-fold more sensitive to the cytotoxic effects, 2-fold more sensitive to the induction of sister chromatid exchanges, and had 3-fold more cross-links formed than 9L cells treated with nitrogen mustard. However, the amount of cell kill, number of sister chromatid exchanges induced, and the DNA cross-linking were the same for 9L and 9L-2 cells treated with cis-diamminedichlorplatinum(II). Our results indicate that cellular resistance to CENUs is highly specific and that the mechanism of resistance does not allow cross-resistance with other DNA cross-linking agents. These and other results suggest that when DNA repair processes mediate cellular resistance to CENUs, other cross-linking agents will not be cross-resistant unless they form alkylation products that are affected by repair processes that mediate resistance to CENUs.

Animals↗

Central nervous system toxicity and cerebrospinal fluid pharmacokinetics of intraventricular 3-[(4-amino-2-methyl-5-pyrimidinyl)ethyl]-1-(2-chloroethyl)-1-nitro soureas and other nitrosoureas in beagles.

The central nervous system toxicity and cerebrospinal fluid (CSF) pharmacokinetics of 3-[(4-amino-2-methyl-5-pyrimidinyl)ethyl]-1-(2-chloroethyl)-1- nitrosoureas, a (ACNU) were determined in beagles and compared to those for three other nitrosoureas, 1-(2-chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea, 1,3-bis(2-chloroethyl)-1-nitrosourea, and chlorozotocin. Of the four drugs, ACNU was tolerated best and at doses of 0.2 to 0.8 mg/week for 8 consecutive weeks. We found that the average half-time for CSF elimination of ACNU was 18 min (range, 12 to 38 min). This value exceeded the known rate of ACNU decomposition in aqueous solution (28 to 29 min), implying that the disappearance of ACNU from CSF was due to hydrolytic decomposition and cellular entry and/or transcapillary loss across central nervous system capillaries. The drug exposure integral (C X t) of ACNU in the CSF after a "toxic dose low" of 0.8 mg in the dogs would achieve the equivalent of in vitro cell kills in excess of 3 logs for rat 9L and human glioma 126 cells. As a potential therapeutic agent for meningeal neoplasia, the major limiting factor may be that the CSF elimination of ACNU is rapid compared to its equilibration time from ventricle to spinal- and cerebral convexity-subarachnoid space. Based on these results, we have instituted clinical Phase I trials of intra-CSF ACNU.

Animals↗

Potentiation by vitamin A of the action of anticancer agents against murine tumors.

Combinations of retinol palmitate (RP) and six different anticancer agents were examined to determine their effects on the life-span of mice bearing ascites sarcoma 180 or P388 leukemia. With ascites sarcoma 180, administration of a fixed dose of RP (3.3 mg/kg) considerably enhanced the antitumor effects of 5-fluorouracil (5-FU) (5 mg/kg, or 20 mg/kg), methotrexate (MTX) (0.5 mg/kg, or 1 mg/kg) and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) (12.5 mg/kg), when given by intraperitoneal injection. However RP failed to potentiate the antitumor effects of adriamycin (ADM) and 6-mercaptopurine (6-MP) against sarcoma 180. With P388 leukemia, RP (167 mg/kg, or 333 mg/kg) enhanced the antitumor effects of 6-MP (25 mg/kg, or 50 mg/kg), MTX (1 mg/kg, or 2 mg/kg), ADM (0.2 mg/kg), ACNU (5 mg/kg) and cis-dichlorodiammine-platinum (CDDP) (1 mg/kg) to a considerable extent, but it did not potentiate the antitumor effect of 5-FU. The combination of RP with ACNU or CDDP was particularly effective against P388 leukemia.

Animals↗

[Multimodality therapy of colorectal cancer].

Multimodality therapy for colorectal cancer is composed of surgery, chemotherapy and irradiation; and hyperthermia joins them recently. As patients with operable colorectal cancer are a good candidate for a chemotherapeutic approach, we began postoperative adjuvant chemotherapy since 1971. On the other hand, our treatment policy towards inoperable cases is various treatments combined with the four therapies described above. The most patients with hepatic metastasis are unamenable for surgery, and they have been mainly treated with intra-arterial chemotherapy. With conventional infusion treatment, however, the infusion drugs are eliminated rapidly from the drainage vein. Thus, we prepared biodegradable albumin microspheres containing MMC (mean diameter 45 +/- 8 micron); and in 6 patients with liver metastasis, we infused MMC microspheres into the proper hepatic artery, with marked tumor regression. Hyperthermia treatment has been performed with ThermaTech 2000 (International Institute for Medical Sciences, U.S.A.), which has a complete capacitive, 3-channel, "crossfire" heating system operating by RF at 13.56 MHz. Six patients with local recurrence and/or hepatic metastasis were treated by hyperthermia combined with chemotherapy or irradiation, with a fair success in tumor response and improvement of subjective symptoms.

Aged↗

Potentiation by squalene of antitumor effect of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-nitros ourea in a murine tumor system.

The effect of squalene (SQ) on the antitumor activity of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitros our ea (ACNU) was studied in a murine tumor system. SQ at 4.2 g/kg exhibited a significant potentiating effect on the activity of 10 mg/kg of ACNU against lymphocytic leukemia P388 and resulted in some long-term survivors without toxicity to the host. Simultaneous administration of SQ and ACNU was most effective.

Animals↗

Clinical evaluation of two combination chemotherapies for the treatment of small cell carcinoma of the lung.

The effects of two different combination chemotherapies, i.e. cyclophosphamide (CPM) + vincristine (VCR) + methotrexate (MTX) and ACNU + VCR, with or without radiotherapy, were studied in twenty patients with untreated small cell carcinoma of the lung. Respective response rates were 66.7% for CVM and 50% for AV. Median survival time was 51 weeks for CVM and 27 weeks for AV. There was no statistically significant difference between the survival probability curves of CVM and AV. Concerning toxicity, two hazardous side effects, myelosuppression and interstitial pneumonitis, were observed although the incidences were low. We concluded that both regimens are useful as chemotherapy of small cell carcinoma.

Aged↗