Chromosome studies on lymphocytes of patients under cytostatic therapy. I. Conventional chromosome studies in cytostatic interval therapy.
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Adult↗
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CCNU-adriamycin association induces earlier and more severe nephropathy in rats.
Adriamycin (ADR) has a broad spectrum of antitumoral activity but is ineffective against human brain tumors. However, such tumors can be sensitive to a combination of adriamycin and lipophilic antineoplastic agents such as the nitrosoureas. CCNU, a nitrosourea, induces cholestasis in the rat and ADR is predominantly excreted via the biliary route. We decided to investigate the effect of CCNU on the nephrotic syndrome induced by ADR. Female Wistar rats were injected with a single dose of 10 mg/kg ADR and 24 h later were force fed 20 mg/kg CCNU in a single dose. Animals were sacrificed 4, 8, 15, 21, 28 or 60 days after the injection of ADR. A high rate of fatality (60%) occurred after the 21st day of treatment. Biological changes (alkaline phosphatase, SGPT, bilirubin) and ultrastructural studies showed that CCNU and CCNU + ADR induced the same degree of cholestasis. With the administered dose, CCNU is not nephrotoxic, ADR induces a nephrotic syndrome and ADR + CCNU appeared more nephrotoxic. With ADR, visceral epithelial foot process fusion was seen on day 15 and tubulo-interstitial lesions and glomerulosclerosis on day 60. With ADR + CCNU fusion of the foot process was seen on day 4, glomerular vacuolation on day 8, tubulo-interstitial alterations on day 15 and glomerulosclerosis on day 60. For both ADR and ADR + CCNU wrinkling and thickening of the basement membrane of proximal tubular cells were seen on day 60. Lipid mesangial overload was seen with ADR and was more intense with ADR + CCNU on day 60. CCNU hepatoxicity modifies the excretion of ADR and the predominantly renal excretion of ADR seems to induce earlier renal alterations in ADR + CCNU-treated rats. This study supports the concept that lipid mesangial overload may play an important role in chronic progressive glomerulosclerosis and thus the ADR + CCNU combination appears to be an interesting model in which to study these relationships.
Animals↗
Carcinogenic N-nitroso compounds and their environmental significance.
A short review is given on the potent and organ-specific carcinogenic effects of N-nitroso compounds. Like many other chemical carcinogens, nitrosamino compounds require activation in vivo via enzymatic alpha-hydroxylation to form alkylating agents as ultimate carcinogens. Since no epidemiological data in man are available, extrapolation of animal data to man are important as well as dose-response studies in risk evaluations. Important aspects of these problems are presented. Finally the environmental impact of N-nitroso compounds is summarized.
Alkylation↗
Acute leukemia in a patient cured of diffuse histiocytic lymphoma.
A patient is described who, after completing treatment for diffuse histiocytic lymphoma, remained disease-free for 7 years (presumably cured), then developed acute nonlymphocytic leukemia (ANLL) after a brief preleukemic phase. Marrow cytogenetic analysis at the onset of frank leukemia revealed loss of chromosomes 5 and 7, which is consistent with secondary leukemia. She received only chemotherapy for her lymphoma, including high doses of an alkylating agent and a nitrosourea, which may have contributed to the development of the leukemia. This case report suggests that secondary ANLL may complicate the course of some long-term disease-free survivors of diffuse histiocytic lymphoma.
Antineoplastic Combined Chemotherapy Protocols↗
DNA adducts and DNA damage by antineoplastic and carcinogenic N-nitrosocompounds.
Mechanisms of DNA adduct formation by antineoplastic 2-chloroethyl-N-nitrosoureas (CNUs) and of DNA damage induced by these compounds as well as by carcinogenic 2-hydroxyalkylnitrosamines are discussed. CNUs are monofunctional and bifunctional alkylating agents that form, in a quantitatively minor reaction, DNA-DNA crosslinks (XL). In vitro, by far the most abundant alkylation products of DNA are those resulting from 2-hydroxyethylation. The reaction sequence responsible for 2-hydroxyethylation comprises intermediate oxazolidine ring closure followed by generation of 2-hydroxyethylnitrosourea and ethylene oxide. Oxadiazolium intermediates have not been found to play a role. In contrast to the in vitro experiments, in vivo 2-hydroxyethyl adducts are formed to a much lesser extent und 2-chloroethyl adducts are predominant in rat kidney DNA. 2-Hydroxyethylation of phosphate groups introduces extreme instability into the sugar-phosphate backbone since the resulting phosphotriester rapidly breaks down through a dioxaphospholane ring intermediate. Measurements of DNA XL in target tumor tissue and in bone marrow provides a sensitive tool for evaluation in bone marrow provides a sensitive tool for evaluation of hormone-linked cytotoxic agents. The potent environmental carcinogen N-nitrosodiethanolamine (NDELA) has been found to be activated in the rat liver by a two-step metabolic transformation sequence involving alcohol dehydrogenase and, subsequently, sulfotransferase. Evidence for this mechanism is provided by measuring DNA single strand breaks in rat liver DNA and by studying the effect of various enzyme inhibitors on the extent of DNA damage induced in vivo by NDELA and its metabolites.
Alkylation↗
Carcinogenesis in F-344 rats induced by nitrosohydroxyalkyl-chloroethylureas.
The two isomeric N-nitroso derivatives of 1-chloroethyl-3-(2-hydroxyethyl)-urea and of 1-chloroethyl-3-(2-hydroxypropyl)-urea were prepared and isolated. They were given by gavage in ethyl acetate/corn oil to groups of 20 male and female F-344 rats. The two nitroso-1-chloroethyl compounds were nephrotoxic and most animals died within 20 weeks; no neoplasms were seen in any of these animals. Nitroso-1-hydroxyethyl-3-chloroethylurea was given at 2 concentrations, 21 and 10.5 mg/ml; in both groups almost all animals died with neoplasms related to the treatment. These included hepatocellular and cholangiocellular neoplasms of the liver; many of the former metastasized. Many rats also had tubular cell neoplasms in the kidney. Nitroso-1-(2-hydroxypropyl)-3-chloroethylurea was a less potent carcinogen at equimolar doses, inducing fewer liver neoplasms than the nitrosohydroxyethyl analog and only few kidney neoplasms. Both of these carcinogens were less effective in female rats than in males, although the females, which were smaller, received a higher dose per unit body weight. The spectrum of neoplasms induced by the nitrosohydroxyalkyl-chloroethylureas was quite different from that induced by equimolar doses of each corresponding nitrosohydroxyalkylurea, neither of which induced neoplasms of the liver, although they were potent inducers of neoplasms in other organs.
Animals↗
Chemotherapy in intracerebrally transplanted tumors induced with transplacental administration of ethylnitrosourea in rats.
Four tumors of the spinal cord were induced with ethylnitrosourea in rats by transplacental administration and transplanted into the brains of animals of the same strain. One of these intracerebrally grafted tumor lines (G-XIII) was followed up over the first 10 passages and treated with CCNU and other alkylating drugs. The results were compared with findings in an earlier established line (G-XII) in passage 12 and 59, which in the first instance was sensitive to CCNU. The CCNU application prolonged survival in treated animals in various treatment schedules in the first 10 intracerebrally grafted generations of the tumor up to 59%. Induction times of tumors became increasingly shorter. The susceptibility of early passages was similar in both lines. Its loss in late passages went together with diffuse growth of the tumor and reticulin fiber production. In addition, glial fibrillary acid protein expression and formation of intermediate filaments in perivascular tumor cells was lost.
Animals↗
Brain tumor chemotherapy using a rat glioma model.
The antitumor agent chloroethylcyclohexyl-nitrosourea (CCNU) was examined using a rat glioma model. A i.p. administration of three times 40 mg/kg CCNU was highly effective and increased the life-span of tumor-bearing rats from 53 to 86%. A total quantity of CCNU amounting to less than 30 mg/kg was not effective. On the other hand, large dosages exceeding LD10 proved to be toxic. The depression of platelets and white blood cells was mild after a single dosage of 40 mg/kg CCNU which recovered on about the 6th day. In the CCNU-treated animals there was an increase of the extent of necrobiosis. Ballooning of tumor cells with nuclear pyknoses and a lack of mitotic features occurred. Microcystic changes appeared sometimes to be more frequent than in control groups.
Animals↗
Examination of four newly synthesized 2-chloroethylnitrosoureas in comparison with BCNU, CCNU, MeCCNU, chlorozotocin and hydroxyethyl-CNU in preterminal rat leukemia L 5222.
The newly synthesized nitrosoureas 1-(2-chloroethyl)-1-nitroso-3-(methylenecarboxamido)-urea (Acetamido-CNU), 1-(2-chloroethyl)-1-nitroso-3-(4-morpholino)-urea (Morpholino-CNU), 1-(2-chloroethyl)-1-nitroso-3-(1-piperidino)-urea (Piperidino-CNU), and 2-[3-(2-chloroethyl)-3-nitrosoureido]-ethylmethanesulfonate (Ethylmethanesulfonato-CNU) were compared in their chemotherapeutic activity against preterminal rat leukemia L 5222 with BCNU, CCNU, MeCCNU, Chlorozotocin, and Hydroxyethyl-CNU. With respect to the dose range effecting a median survival time of more than 90 days, MeCCNU was superior to the other substances. Chlorozotocin, on the other hand, was the only substance which achieved no cures in this experimental arrangement. From the four newly introduced substances the water-soluble substances Acetamido-CNU and Morpholino-CNU were approximately comparable to CCNU with regard to the dose range effecting a median survival time of greater than 90 days. Piperidino-CNU and Ethylmethanesulfonato-CNU also effected cures; however, only Piperidino-CNU in one dosage effected a median survival time of greater than 90 days.
Animals↗
Stability of solutions of antineoplastic agents during preparation and storage for in vitro assays. General considerations, the nitrosoureas and alkylating agents.
In vitro drug sensitivity of tumour biopsies is currently being determined using a variety of methods. For these chemosensitivity assays many drugs are required at short notice, and this in turn means that the drugs must generally be stored in solution. There are, however, a number of potential problems associated with dissolving and storing drugs for in vitro use, which include (a) drug adsorption; (b) effects of freezing; (c) drug stability under the normal conditions of dilution and setting up of an in vitro assay; and (d) insolubility of drugs in normal saline (NS) or phosphate-buffered saline (PBS). These problems are considered in general, and some recommendations for use of solutions of drugs in in vitro assays are suggested. The nitrosoureas and alkylating agents are also investigated in greater detail in this respect. The nitrosoureas are found to be very labile in PBS at pH 7, with 5% degradation (t0.95) occurring in 10-50 min at room temperature. These values are increased about 10-fold on refrigeration and about 5- to 10-fold on reduction of the pH of the medium to pH 4-5. At pH 7 and room temperature, t0.95 is observed in under 1 h with the alkylating agents nitrogen mustard, chlorambucil, melphalan, 2,5-diaziridinyl-3,6-bis(2-hydroxyethylamino)-1,4-benzoquinone (BZQ), dibromodulcitol, dibromomannitol, treosulphan, and procarbazine. Of the other alkylating agents, 4-hydroperoxycylophosphamide (sometimes used in vitro in place of cyclophosphamide), busulphan, dianhydrogalactitol, aziridinylbenzoquinone (AZQ), and dacarbazine have a t0.95 of between 2 and 24 h, while ifosfamide and pentamethylmelamine are both stable in aqueous solution for greater than 7 days. About half the drugs studied in detail have been stored frozen in solution for in vitro use, although very little is known about their stability under these conditions.
Alkylation↗
Effect of nitrosoureas on calmodulin activity in vitro and in mouse intestine in vivo.
The effects of BCNU, CCNU, methyl-CCNU, streptozotocin, and chlorozotocin on calmodulin activity were studied in vitro and in vivo. Preincubation of BCNU, CCNU, and methyl-CCNU with calmodulin produced a concentration-dependent inhibition of in vitro calmodulin activity expressed as stimulation of cyclic nucleotide phosphodiesterase. Cyclohexylisocyanate produced a similar inhibition. Streptozotocin and chlorozotocin had no effect. Calmodulin inhibition by methyl-CCNU was dependent on the concentration of calcium in the preincubation mixture. Administration of methyl-CCNU or chlorozotocin IP to CF1 mice produced a dose-dependent inhibition of calmodulin activity in the small intestine. Methyl-CCNU produced a significant decrease in intestinal calmodulin activity as early as 1 h after treatment, an effect that persisted up to 52 h. Morphologic changes in the intestinal crypt epithelial cells were evident between 27 h and 5 days after treatment, but not earlier than 27 h. Renal and testicular calmodulin activity and morphology were unaffected. Although it was not possible to correlate the extent of calmodulin inhibition with severity of the intestinal lesions, the data suggested a relationship between reduced activity of calmodulin in a tissue and the ultimate appearance of lesions. This apparent interaction between an antitumor drug and calmodulin in vivo could have multiple implications for cancer chemotherapy.
Animals↗
MItomycin C, methyl-CCNU and 5-fluorouracil in the treatment of metastatic colorectal carcinoma.
The combination of mitomycin C, methyl-CCNU and 5-fluorouracil produced no objective tumor regressions in 25 evaluable patients with metastatic colorectal carcinoma. Patients who achieved stable disease survived significantly longer than patients who had progressive disease. This difference appeared to be more probably related to pre-treatment characteristics of the patients than caused by treatment. Serial CEA determinations revealed a parallel relationship with tumor behavior in 17 of 19 patients.
Adult↗
Two randomized trials for alternating polychemotherapy of small cell lung cancer.
Patients with small cell carcinoma of the lung (SCCL) were treated in two multicenter trials with different cytostatic drug regimens including ifosfamide. In the first randomized study, including 306 patients, alternating chemotherapy with VP 16, ifosfamide, vindesine (VPIV), adriamycin, cisplatinum, vincristine (APO), and cyclophosphamide, methotrexate, CCNU (CMCC) was compared against standard treatment with ACO (adriamycin, cyclophosphamide, vincristine). It was shown that the alternating therapy resulted in a higher response rate (88% vs 78%) and a longer median survival time (11 months vs 10 months). Regarding toxicity, VPIV was similar to ACO, whereas APO and CMCC had more side-effects, leading to an increase in the number of drop-outs. In the second randomized study 144 patients were treated either with ifosfamide/VP 16 (IVP) or with cisplatinum/VP 16 (PVP). In the case of no further response, no change, or progression the induction therapy was changed to ACO. Interim analyses show that both regimens have similar therapeutic effects; but higher toxicity was observed in patients treated with cis-platinum/VP 16 than in patients treated with ifosfamide/VP 16. According to the response rate in patients treated with ACO after first-line therapy there was less cross-resistance of IVP than of PVP to ACO.
Age Factors↗
In vitro chemosensitivity testing of Fotemustine (S 10036), a new antitumor nitrosourea.
Fotemustine (S 10036) is a new anti-tumor nitrosourea characterized by a phosphonoalanine carrier group coupled to the nitrosourea moiety, which potentially increases the cellular penetration of the drug. Using human tumor cell lines, the activity of S 10036 was compared with that of the more established nitrosoureas BCNU and CCNU. Growth-inhibiting effects were evaluated by the [3H]-thymidine incorporation test. In a panel of 12 human cancer cell lines [melanoma (4), ovary (2), head and neck (3), lung (1), bladder (1), breast (1)], the dose-response curves of S 10036 (0-100 microM) were similar to those obtained with equimolar concentrations of BCNU and CCNU; they indicated a moderately more marked effect for two and an equal effect for six melanoma cell lines with S 10036 as compared with BCNU. Moderate but significant synergistic combinations were obtained when S 10036 (0-80 microM) and CDDP (0-100 microM) or DTIC (250-6,500 microM) were combined in melanoma cell lines. In conclusion, the new nitrosourea S 10036 shows promising activity, particularly against human melanoma cell lines.
Antineoplastic Agents↗
Astroblastoma revisited: a report of three cases.
The very existence of astroblastoma has been a question of considerable controversy, although there appears now to be sufficient documentation to establish it as a tenable entity. Due to the rarity of this tumor, little information exists in the literature as to its natural history, efficacy of therapy and its pathological and radiological appearance. We report three cases of astroblastoma, describing their natural history, the response to therapeutic interventions and their light microscopic, ultrastructural and immunohistochemical characteristics.
Adult↗
Depletion of O6-alkylguanine-DNA alkyltransferase activity in mammalian tissues and human tumor xenografts in nude mice by treatment with O6-methylguanine.
We have previously shown that exposure of cells in culture to O6-methylguanine significantly reduces their level of the repair protein, O6-alkylguanine-DNA-alkyltransferase (AGT), thus rendering cells more sensitive to the cytotoxic effects of chemotherapeutic chloroethylating agents. Experiments were carried out in mice to determine whether the AGT content of tissues and tumors could be reduced by in vivo treatment with O6-methylguanine. There was a dose-dependent decrease in AGT activity in liver tissues of CD-1 mice to 24% of basal levels after four hourly intraperitoneal injections of O6-methylguanine (110 mg/kg). Although the decline in AGT activity in the liver was reversible, the activity remained at 75% of basal levels for up to 25 h after the final injection. The effect of O6-methylguanine treatment on AGT activity was measured in mouse tissues as well as human colonic carcinoma tumors (HT29 and BE) grown in Swiss athymic nude mice. The activity in the liver, kidney, and spleen of these mice decreased to 33%-35% of control levels, whereas the activity in HT29 tumors was likewise diminished to 25% of control levels after four hourly injections of O6-methylguanine (100 mg/kg). There was no enhancement of the tumoricidal effectiveness of chloroethylating agents on the HT29 tumor after O6-methylguanine treatment, probably due to a disproportionately higher level of AGT in human tissue than in murine tissue. However, these studies suggest that O6-methylguanine can be given in vivo to examine the role of the AGT protein in protecting against the toxic and carcinogenic effects of alkylating agents.
Animals↗
Pre-irradiation chemotherapy in children with high-grade astrocytoma: tumor response to two cycles of the '8-drugs-in-1-day' regimen. A Childrens Cancer Group study, CCG-945.
PURPOSE: This study was undertaken to evaluate the radiographic response to two cycles of chemotherapy prior to irradiation in newly diagnosed children with high-grade astrocytomas. PATIENTS AND METHODS: One hundred and thirty children less than 21 years of age with newly-diagnosed high-grade astrocytoma were treated with the 'eight-drugs-in-one-day' chemotherapy regimen as part of a phase III multi-institutional Childrens Cancer Group (CCG) trial. Computerized Tomographic (CT) or Magnetic Resonance Image (MRI) scans, obtained after two cycles of chemotherapy had been administered, were compared with post-operative scans to determine treatment response. Scans were evaluated by institutional radiologists, and were reviewed centrally by a single neuroradiologist. RESULTS: Of 79 patients with evaluable post-operative residual tumor on CT or MRI scans, 26 (33%) were determined on institutional evaluation to have had an objective response. However, central review of scans documented responses on only 14/79 (18%). A significantly higher response rate on central review was observed for those children 36 months of age or less at study entry than for older children (33% v 11%; p < 0.001). However, a higher disease progression rate was also observed for those children 36 months of age or less than for older children (21% v 2.6%; p < 0.001). CONCLUSION: In this study, the largest yet reported in newly-diagnosed children with high-grade astrocytomas, the chemotherapy regimen has activity in younger children. The differences in response rates reported by institutional and central review highlight the difficulties inherent in assessing response to brain tumor therapy. However, the study does demonstrate the consistent ability of radiologists to identify disease progression within the institutional and central reviews.
Adolescent↗
Malignant gliomas treated after surgery by combination chemotherapy and delayed irradiation. Part I: Analysis of results.
Forty-six patients with gliomas were introduced after surgery into a therapeutic programme of six cycles of combination chemotherapy with VM26 and CCNU, followed by delayed irradiation six months after surgery with an average dose of 5,800 rads. After irradiation the same preradiation chemotherapy was readministered for an average of four cycles. The results were compared to those from another group of 28 patients treated only by the same chemotherapy (CRC and C groups sucessively). Twelve patients (26%) died before irradiation in the CRC group, six patients (13%) had recurrences at the time of irradiation, and 28 patients (61%) had no clinical or radiological signs of recurrence at the time of irradiation. For the total of treated patients the median survival after surgery was 17 months, and 46% of the patients were surviving at 18 months. The percentage of survivors at 18 months was significantly more elevated in the group treated by combination chemotherapy and delayed irradiation than in a control group treated by the same combination chemotherapy alone. This result suggests that in approximately 50% of cases combination chemotherapy after surgery, and delayed irradiation six months after surgery, cumulated their effects on survival time.
Adolescent↗