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Biomedical subjects

W Pahlke

Publications and source records attributed to W Pahlke.

10 recordsLinked to original sources

In vivo antitumor activity of ilmofosine.

Ilmofosine is a cytostatic/cytotoxic thioether phospholipid derivative. The in vivo anti-tumour activity of this compound was investigated in a methylcholanthrene (MethA)-induced fibrosarcoma and in the 3Lewis-lung carcinoma systems, respectively. Ilmofosine showed antineoplastic and antimetastatic properties at oral doses ranging from 0.625 to 40 mg/kg/day. Combination of Ilmofosine (p.o.) together with either cyclophosphamide (p.o.) or cis-DDP (i.v.) resulted in synergistic effects in vivo. These results demonstrate the in vivo antitumour activity of Ilmofosine in two tumour systems. The data indicate that direct cytostatic/cytotoxic effects of Ilmofosine are mainly responsible for its antitumour activity in vivo and which are increased by other cytotoxics.

Animals↗

Antineoplastic activity of the thioether lysophospholipid derivative BM 41.440 in vitro.

Thioether lysophospholipid derivatives (TLP) inhibited the in vitro uptake of [3H]thymidine into blasts of eight leukemias and cells of 12 different solid tumors of human origin. This effect correlated with trypan blue dye exclusion, which was used to assess cell damage. Cytostatic and cytotoxic effects of TLP were dependent on dosage and incubation time. Destruction of leukemic blasts was completed with greater than 5 micrograms/ml after an incubation of greater than 48 hr, but 10 to 20 micrograms/ml were necessary in solid tumors. Ester-linked 2-lysophosphatidylcholine was ineffective in the same dose range, which points to the requirement of the alkyl moiety in sn-1 and a stable sn-2 substitution of the molecule for the antineoplastic effect. To assess putative antileukemic selectivity, the cytotoxicity (trypan blue dye exclusion) of TLP was compared in human cell samples of 19 non-neoplastic bone marrows and 9 leukemias. Results revealed a significantly higher activity of the TLP BM 41.440 in leukemic blasts.

Antineoplastic Agents↗

Synthesis of thioether phosphocholine analogues.

The synthesis of thioether phospholipids, which represent a new class of antitumor agents, is reported here. In particular, the route of synthesis of 3-hexadecylmercapto-2-methoxymethylpropyl-2'-trimethylammoni o-ethyl phosphate (BM 41.440, Ilmofosine), one of the most potent cytostatic/cytotoxic derivatives, is described in detail. Starting with diethyl bis-hydroxymethylmalonate, ethyl 2-phenyl-1,3-dioxane-5-carboxylate is formed via diethyl 2-phenyl-1,3-dioxane-5,5-dicarboxylate and 5-ethoxycar-bonyl-2-phenyl-1,3-dioxane-5-carboxylic acid. Reduction of ethyl 2-phenyl-1,3-dioxane-5-carboxylate with LiAlH4 affords 5-hydroxymethyl-2-phenyl-1,3-dioxane. Alkylation with dimethyl sulfate gives 5-methoxymethyl-2-phenyl-1,3-dioxane. The ring structure then is opened by N-bromosuccinimide, resulting in the formation of 3-bromo-2-methoxymethylproply benzoate. Reaction of 3-bromo-2-methoxymethylpropyl benzoate with the sodium salt of hexadecanethiol leads to 3-hexadecylmercapto-2-methoxy-methylpropanol, which is reacted with a cyclic chlorophosphate to give the corresponding phosphorylated 3-hexadecylmercapto-2-methoxymethylpropanol. Treatment with trimethylamine yields BM 41.440. This compound already has been tested in clinical phase I/II trials in West Germany.

Antineoplastic Agents↗

Pharmacokinetics of the thioether phospholipid analogue BM 41.440 in rats.

BM 41.440 (1-hexadecylmercapto-2-methoxymethyl-rac-glycero-3-phosphocholine) is a cytotoxic thioether phospholipid analogue that recently has entered phase I trials in cancer patients. The objective of this study was to evaluate the pharmacokinetics of this compound in female rats after administration of a single oral dose (15 mg/kg body weight [bw] ). Furthermore, BM 41.440 serum concentrations were determined under a daily oral treatment of up to 13 weeks. Blood samples were obtained via permanent catheters from the femoral arteries before and after drug administration for a total of 120 hr. Urine was collected in 24 hr-intervals for 120 hr; the volume was measured, and aliquots were stored at -20 C until analytical determination of the thioether derivative. BM 41.440 was assayed in serum and urine by means of a specific, newly developed reverse-phase high pressure liquid chromatography technique. Mean maximum serum concentrations (1.7 micrograms/ml, n = 4 animals) were attained after seven hr. A terminal half-life of ca. 27 hr was calculated from the rate constant for the terminal elimination phase (lambda z approximately 0.026/hr). The mean serum BM 41.440 concentration-time-area-under-the-curve was 52.9 mg X hr/l. The ratio of total body clearance to absorption fraction was 4.7 ml/min X kg bw. Only a small amount of the drug was found in the urine. The quantity excreted in the urine during a 24 hr-interval never exceeded 1.5% of the administered dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

BM 41.440: a new antineoplastic, antimetastatic, and immune-stimulating drug.

Alkyllysophospholipids are analogs of the cell membrane component lysophosphocholine. The thioether lysophospholipid BM 41.440 (1-hexadecylmercapto-2-methoxymethyl-rac-glycero-3-phosphocholine) is already in use in phase I and II trials in human cancer therapy. A direct antitumor effect of this new compound has been shown in vitro using 35 different cell types of murine and human origin. All normal cells investigated were not affected in the concentration range (1-10 micrograms/ml) that was cytotoxic for most tumor cells studied. In vivo, antimalignant and antimetastatic actions have been documented in the Meth A sarcoma, L1210 leukemia, B 16 melanoma and the 3Lewis-lung carcinoma tumor models, respectively. Murine, bone marrow-derived macrophages (M phi), preincubated with BM 41.440, showed an increased cytotoxicity in vitro. Addition of syngeneic spleen cells and low doses of BM 41.440 to this system enhanced tumor cell destruction 20- to 100-fold compared to controls dependent on the target cells used (YAC, ABLS-8.1, L1210, and P815). In vivo, Meth A sarcoma growth was dose and time dependently reduced in CB6F1 mice under therapeutic IV application of BM 41.440-activated M phi. The mean survival time of DBA mice, treated once IP with BM 41.440 4 days before L1210 challenge, increased from 24 to 38 days.

Alkaline Phosphatase↗

Ciamexone--a new highly selective immunosuppressive compound.

A local graft versus host reaction between lymphocytes of Balb-c mice and its F-1-generation CB6F1 can be induced because of differences in products of the class II of the major histocompatibility complex (Ir). In this local mixed lymphocyte reaction mainly T-helper cells and B-cells are involved. An induction of a delayed type hypersensitivity reaction with oxazolon significantly decreases the local graft versus host reaction. Cyclosporin A depresses the local graft versus host reaction and the delayed type hypersensitivity in mice whereas Ciamexone, a 2-cyanaziridine derivative, very selectively only suppresses the local graft versus host reaction and increases the delayed type hypersensitivity.

Animals↗

Treatment of autochthonous rat colonic adenocarcinomas with a thioether-lysophospholipid derivative in mono- and combination chemotherapy.

In 361 Sprague-Dawley rats autochthonous colorectal carcinomas were induced by intrarectal application of the carcinogen AMMN. Tumor-bearing animals were treated with a synthetic thioether-lysophospholipid (TLP) derivative and in combination chemotherapy with 5-fluorouracil (5-FU) and carmustine (BCNU). There was no difference in the survival time of treated and untreated animals. The median large-bowel tumor weight was significantly lower in the TLP/5-FU and TLP/5-FU/BCNU combination therapy groups than in the control groups. Transient hepatotoxicity was observed in the high-dosage (50 mg/kg body weight twice weekly) TLP group. This study confirmed the relative resistance of AMMN-induced colorectal carcinomas to antineoplastic treatment.

Adenocarcinoma↗

Cytotoxicity of thioether-lysophospholipids in leukemias and tumors of human origin.

Thioether-lysophospholipids inhibited the in vitro incorporation of [3H]thymidine into blasts of 8 leukemias, lymphocytes of 3 chronic lymphocytic leukemias, and cells of 12 different solid tumors of human origin. This effect correlated with trypan blue dye exclusion, which was used to assess cell damage. Scanning electron microscopy revealed severe membrane destruction after incubation with thioether-lysophospholipids. Cytostatic and cytotoxic effects of thioether-lysophospholipids were dependent on dosage and incubation time. Destruction of leukemic blasts was completed with greater than or equal to 5 micrograms/ml after an incubation of greater than or equal to 48 hr, but 10 to 20 micrograms/ml were necessary in solid tumors. Ester-linked 2-lysophosphatidylcholine was ineffective in the same dose range, which points to the requirement of the alkyl moiety in SN1 of the molecule for the antineoplastic properties of lysophospholipid analogues.

Adenocarcinoma↗

Disturbance of phospholipid metabolism during the selective destruction of tumor cells induced by alkyl-lysophospholipids.

Alkyl-lysophospholipids inhibit the growth of Meth A sarcoma cells in vitro. In contrast, murine bone marrow macrophages are not sensitive to the destructive effect of these substances. Since alkyl-lysophospholipids are antimetabolites in the synthesis of 3-sn-phosphatidylcholine, tumor cell destruction can be correlated with the disturbance of this metabolism. A decreased synthesis of 3-sn-phosphatidylcholine is accompanied by an increased degradation of cellular 3-sn-phosphatidylcholine in the presence of alkyl-lysophospholipids. As a consequence, endogeneously formed lysophospholipid accumulates, although the lysophospholipase is found to be stimulated. This accumulation of endogeneous lysophospholipids might be due to the fact that a high percentage of these compounds contain an alkyl bond which cannot be split by a lysophospholipase. On the other hand, the reacylation of the formed lysophospholipids is partially blocked as the lysophosphatidylcholine acyltransferase is inhibited by the added alkyllysophospholipids. An accumulation of potentially cytotoxic lysophospholipids in tumor cells might be an additional factor in the tumor cell destruction by alkyl-lysophospholipids.

Animals↗