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Biomedical subjects

M R Berger

Publications and source records attributed to M R Berger.

At least 19 recordsLinked to original sources
PubMed2003

Effect of 2-methoxyestradiol on the growth of methyl-nitroso-urea (MNU)-induced rat mammary carcinoma.

The present study investigated the influence of the endogenous estradiol metabolite 2-methoxyestradiol (2ME) on the growth of methyl-nitroso-urea (MNU)-induced mammary carcinoma in the rat. 2ME was administered by means of subcutaneously implanted osmotic pumps for a period of 4 weeks. The dosages of 2ME were 1 and 5mg/kg per day, the control animals received saline. At the low dosage of 2ME a stimulation of tumor growth was observed, whereas at the high dosage an inhibition was found. The urinary excretion of 15 estradiol metabolites revealed that 2ME triggered strong changes in estrogen metabolism in the organism. Our data show that 2ME may elicit both stimulation and inhibition of tumor growth depending on the dosage used, a fact which should be considered in case of therapeutic use.

2-Methoxyestradiol↗
PubMed2002

Cytotoxic efficacy of bendamustine in human leukemia and breast cancer cell lines.

PURPOSE: The purpose of this study was to characterise bendamustine's cytotoxic and apoptotic activity in a panel of leukemia and breast cancer cell lines in comparison to its clastogenicity in murine bone marrow. METHODS: The cytotoxic effect of bendamustine was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT)-dye reduction assay. Induction of apoptosis was evidenced by DNA gel electrophoresis, nuclear staining, Western blot poly-(adenosine diphosphate-ribose) polymerase (PARP) cleavage, and flow cytometry. As a measure of hematological toxicity, the formation of chromosomal aberrations was investigated in bone marrow cells isolated from mice treated with low non-toxic doses of bendamustine and lomustine. RESULTS: Bendamustine was preferably active against leukemic cells of lymphoid origin and was found to induce apoptosis in SKW-3 and BV-173 cells as shown by oligonucleosomal DNA and nuclear fragmentation, PARP cleavage, and formation of a sub-G1 fraction. Myeloid and breast carcinoma cell lines were resistant towards bendamustine with the exception of HL-60 cells which exhibit an intermediate sensitivity. Bendamustine was found to have a very low clastogenic effect as compared with equimolar doses of lomustine. CONCLUSION: Taken together, the mode of action of bendamustine includes induction of apoptosis. The specific spectrum of activity and the unexpectedly low clastogenicity support the hypothesis that bendamustine in not a typical alkylating agent but exerts an additional mode of action, possibly as a purine antimetabolite.

Animals↗
PubMed1999

Sensitive detection of K-ras mutations augments diagnosis of colorectal cancer metastases in the liver.

Postoperative survival of colorectal cancer patients is often delineated by metastases spreading to the liver. Current clinical diagnostic procedures are unable to discover micrometastases in this organ. Our aim was to develop a diagnostic tool for detecting micrometastases that are present at the time of surgery. Therefore, a PCR-RFLP assay was set up tracking point mutations of the K-ras oncogene at codons 12 and 13, based on mismatch primers and restriction enzymes BstXI and XcmI. The detection limit of this assay was one mutant in one million wild-type cells. One hundred forty-two patients with colorectal carcinoma were screened for these mutations in tissue samples from their tumor, proximally adjacent mucosa, and liver. Of these, 67 patients (46%) were positive for a K-ras mutation, of which 58 had codon 12 and 9 had codon 13 mutations. No patient without a K-ras-positive tumor showed a mutation in mucosa, but 11 patients with a K-ras-positive tumor (11 of 58; 19%) were found to bear a K-ras mutation in their mucosa, and in 21 patients (21 of 64; 33%), a K-ras mutation was detected in liver tissue. Sequencing of all mutated samples revealed a 92% confirmation of PCR-RFLP results. In summary, the assay is a useful tool for detecting K-ras codon 12 and 13 mutations and allows early proof of molecular determinants of liver metastases. Such knowledge will improve the staging of colorectal cancer patients and could beneficially influence their prognosis if followed by an effective therapy.

Adult↗
PubMed1999

Human urinary bladder carcinoma cell lines respond to treatment with alkylphosphocholines.

Alkylphosphocholines (APC) constitute a new group of antineoplastic agents without haematological toxicity. Their first clinically available derivative hexadecylphosphocholine (miltefosine) is locally used to control skin metastases of breast cancer. Since intravesical chemotherapy represents a form of topical treatment we investigated whether a new APC with a long alkyl chain would be active against 5637 and EJ bladder cancer cell lines. Their antineoplastic activity was inversely related to the alkyl chain length of the respective APC. Erucylphosphocholine and its congener with modified phosphocholine head erucylphospho-N,N,N-trimethylpropanolamine were the most effective derivatives. APC with alkyl chains over 16 carbons in length induced programmed cell death in both cell lines, as determined by oligonucleosomal DNA fragmentation and morphology. The distinct antineoplastic effects lead us to predict that urinary bladder instillation of APC will be of therapeutic benefit for patients with urinary bladder neoplasia.

Antineoplastic Agents↗
PubMed1999

Quantitative detection of lac-Z-transfected CC531 colon carcinoma cells in an orthotopic rat liver metastasis model.

Disseminated colon carcinoma metastases in the liver are associated with low cure rates and constitute a serious therapeutic problem. Appropriate experimental models which mimic metastases development and outgrowth can provide insight into the mechanism of this lethal process and facilitate the finding of new approaches for its control. We established an orthotopic liver metastases model based on CC531 rat colon adenocarcinoma cells which were transfected with a beta-galactosidase gene as marker to facilitate their detection. Intraportal injection of CC531-lac-Z cells resulted in a rapid and locally aggressive growth within the liver and was characterised by a tumour volume doubling time of 20 h and abundant angiogenesis. A commercially available chemi-luminescence assay allowed rapid, quantitative and sensitive detection of the diffusely growing tumour cells. Immunogenicity of CC531-lac-Z cells induced by the marker gene was significantly reduced by co-administering the tumour cells with matrigel. Within an observation period of three weeks following tumour cell injection only 6% of the animals showed lung involvement, thus indicating a specific homing of CC531-lac-Z cells to the liver. This period appears long enough to allow therapeutic manipulations at various stages of tumour growth in the liver. It is envisaged that the model will have applications for various therapeutic strategies.

Animals↗
PubMed1999

BCR-ABL influences the antileukaemic efficacy of alkylphosphocholines.

We have compared the antileukaemic efficacy of a series of new i.v. injectable alkylphosphocholines (APC) with their clinically used congeners miltefosine and perifosine. The test system consisted of four leukaemic cell lines carrying the bcr-abl rearrangement (K-562, LAMA-84, CML-T1 and BV-173) and two other leukaemic cell lines (HL-60 and SKW-3) without this genetic alteration. The prototype of i.v. injectable APC, erucylphosphocholine, was more active against BCR-ABL-positive cell lines than the two reference APC. It induced programmed cell death in HL-60 and SKW-3 cells after exposure for 24 h, and in bcr-abl expressing cells after a prolonged incubation period (48 h). LAMA-84 cells responded to i.v. injectable APC with increased conversion to an adherent, fibroblast-like phenotype. Experiments with a cell-free system showed that the target structures of APC are localized within the cytoplasmic compartment. Blockade of ceramide synthase by fumonisin B1 was insufficient to prevent oligonucleosomal DNA fragmentation. Using RT-PCR we confirmed that K-562 and LAMA-84 cells carry the b3a2 fusion type, and CML-T1 and BV-173 the b2a2 variant. BV-173 cells had the lowest level of bcr-abl mRNA which correlated with their increased sensitivity. Transfection of K-562 cells with antisense oligonucleotides directed against bcr-abl caused a specific suppression of K-562 clonogenicity. Our data indicated that i.v. injectable alkylphosphocholines are potent inducers of apoptosis and display increased antileukaemic efficacy against BCR-ABL-positive blasts as compared with miltefosine and perifosine. The expression of BCR-ABL cannot prevent apoptosis but delays erucylphosphocholine-induced programmed cell death. Transfection with bcr-abl directed antisense oligonucleotides reduces the clonogenicity of K-562 cells.

Apoptosis↗
PubMed1999

Sampling technique influences the detection of K-ras mutations in normal appearing mucosa of colorectal cancer patients.

Based on three colorectal cancer cell lines with specified K-ras status, a sensitive PCR-RFLP assay was established detecting one K-ras mutant among 106 wild-type cells. Using this assay for tissues of 124 colorectal cancer patients, 59 tumor (46%) and 11 mucosa samples (9%) were found to harbor a K-ras mutation. When using the same scalpel for collecting tumor and mucosa tissues (group A), 18% of the patients had a matching K-ras mutation in both tissues, but this coincidence was seen in 3% of patients only, when separate scalpels were used (group B). Thus we conclude that the sampling technique used for collecting specimens is a major contributor to the detection of K-ras mutations in normal appearing mucosa when a highly sensitive detection technique is used.

Aged↗
PubMed1998

Alkylphosphocholines: Effects on human leukemic cell lines and normal bone marrow cells.

The anti-leukemic activity of a series of alkylphosphocholines (APCs) was studied against a panel of human leukemic cell lines (HL-60, K-562, Reh, MOLT-4, Jurkat, Ramos and Raji). Cytotoxic efficacy was measured by the MTT cell survival assay. All cell lines were found to be sensitive, except the multipotential CML-derived K-562 cell line. Flow cytometry of HL-60 cells showed a significant decrease of cells in S phase and the formation of a sub-G fraction. DNA fragmentation typical for programmed cell death was detected by DNA gel electrophoresis in these cells but not in any of the other leukemic lines. At concentrations below the cytotoxic range, mitogenic effects were seen in HL-60 cells after 14-hr exposure. Colony formation by K-562 cells revealed an augmented clonogenicity after exposure to APC with a short alkyl chain. In contrast, cells of lymphoid origin did not undergo DNA fragmentation or show mitogenic stimulation after exposure to APC. Normal bone marrow cells were also investigated for mitogenic and genotoxic effects. No decrease was found in the number of hematopoietic progenitors in long-term bone marrow cell cultures after exposure to APC. On the contrary, a significant increase was found after short exposure. Dodecylphosphocholine, hexadecylphosphocholine (HPC) and (octadecyl-[2-(N-methylpiperidino)-ethyl]phosphate exhibited a mild clastogenicity at equimolar high doses on murine bone marrow cells in vivo, which is unusual for the majority of classical DNA-interacting anti-cancer drugs. In conclusion, APCs are agents with a broad spectrum of in vitro anti-leukemic effects, which lack hematological toxicity.

Alkylation↗
PubMed1998

Alkylphosphocholines induce apoptosis in HL-60 and U-937 leukemic cells.

Alkylphosphocholines (APC) represent a new group of ether-lipid-related compounds with remarkable activity against transformed cells in vitro and good tolerability in vivo. Their mechanism of action remains unknown. The aim of the present study was to investigate the effects of a series of APC on three human leukemic cell lines: K-562, HL-60, and U-937. The tetrazolium dye-reduction (MTT) assay and cell counting were used to determine the cytotoxicity of the APC used. DNA gel electrophoresis and enzyme-linked immunosorbent assay (ELISA) detection of oligonucleosomes were performed to identify and quantify DNA fragmentation. Electron and phase-contrast microscopy were used to detect morphologic changes specific for programmed cell death. HL-60 and U-937 cells were found to be sensitive, but K-562 cells were relatively resistant to APC exposure. APC with long alkyl chains exerted stronger cytotoxicity than did those with short alkyl chains. DNA fragmentation was found after treatment with APC in HL-60 and U-937 cells but not in K-562 cells. In HL-60 cells the increase in mono- and oligonucleosome formation as measured by ELISA was correlated with the length of the alkyl chains at 14 h of exposure to APC but plateaued at 20 h. The morphologic alterations in HL-60 and U-937 cell lines, such as cell shrinkage, chromatin condensation, and formation of apoptotic bodies, confirmed the induction of apoptosis after APC exposure. It is concluded that programmed cell death plays an important role in the cytotoxicity of APC against certain human leukemic cell lines. The antineoplastic profiles of APC with long alkyl chains render them attractive for further therapeutic application.

Apoptosis↗
PubMed1997

Efficacy of anticancer alkylphosphocholines in Trypanosoma brucei subspecies.

Tetradecylphosphocholine (TPC), hexadecylphosphocholine (HPC), hexadecylphospho(N-N-N-trimethyl)hexanolamine (HPC6), octadecylphosphocholine (OPC), and octadecyl-[2-(N-methylpiperidinio)ethyl]-phosphate (OMPEP) were investigated for antitrypanosomal activity in vitro and in vivo. OMPEP showed the best trypanocidal efficacy in vitro; it was superior to the model compound HPC and comparable to the reference compound alpha-DFMO. HPC showed moderate activity in vivo in terms of increased life expectancy (up to 35% in the acute NMRI-mouse model or 49% if combined with phenylbutazone) and increased packed cell volume, if administered daily. However, HPC and the other alkylphosphocholines failed to prolong survival time of treated mice if given intermittently. Phenylbutazone had no own trypanocidal effect but increased the efficacy of alkylphosphocholines in vitro and in vivo: the combination of HPC and phenylbutazone acted apparently synergistic.

Animals↗
PubMed1996

Application of alpha-aminoisobutyric acid, L-methionine, thymidine and 2-fluoro-2-deoxy-D-glucose to monitor effects of chemotherapy in a human colon carcinoma cell line.

Up to 4 h after treatment of human SW 707 colon carcinoma cells with the antineoplastic drug 4-amino-N-(2'-aminophenyl)-benzamide (GOE 1734, dinaline), the effects of tumour cell metabolism and proliferation were examined in vitro. Four tracers which can be labelled with isotopes suitable for positron emission tomography (PET) were used for this purpose: alpha-aminoisobutyric acid (AIB) and methionine to study changes in amino acid transport and protein synthesis, thymidine to observe changes in tumour proliferation and 2-fluoro-2-deoxy-D-glucose (FDG) to estimate glucose metabolism. Dinaline showed an inhibition of the sodium-dependent and -independent uptake of AIB. The methionine uptake was found to increase shortly after therapy. Thymidine incorporation into DNA was impaired and the FDG uptake showed a maximally 2.2-fold enhancement. Inhibition of AIB uptake suggests changes in amino acid transport, whereas increased uptake of methionine and FDG points to an enhancement of protein synthesis and glycolysis caused by repair mechanisms. The cytostatic and antiproliferative effect of dinaline, observed in cell growth curves, could be demonstrated by the impaired thymidine incorporation into DNA. This study demonstrates that in vitro screening with radiotracers suitable for PET can help to clarify effects of new antineoplastic substances on tumour cell metabolism. These data may be applied to choose the appropriate time schedule for monitoring therapeutic effects on tumour tissue.

Aminoisobutyric Acids↗
PubMed1996

Efficacy of dinaline and its methyl and acetyl derivatives against colorectal cancer in vivo and in vitro.

Dinaline [4-amino-N-(2'-aminophenyl)-benzamide, Din], p-N-methyldinaline (Me-Din) and p-N-acetyldinaline (Ac-Din) were evaluated for their antineoplastic efficacy in acetoxymethylmethylnitrosamine-induced colorectal carcinomas in Sprague-Dawley rats and in two human colon cancer cell lines. Din was very effective at all dosages (10, 7.7 and 5.9 mg/kg) as indicated by the ratio of median tumour volume of treated and control groups (T/C%) values of 0.4, 16 and 10.6, respectively, but also caused a corresponding mortality of 87, 47 and 13%, respectively, as opposed to 15% in the control group. Me-Din also showed significant tumour growth inhibition at all dosages (13.8, 10.6, 8.2 and 6.2 mg/kg), as evidenced by T/C% values of 2, 5.7, 8.4 and 25, respectively. The corresponding mortality was 47, 20, 27 and 30%, respectively. Ac-Din showed the lowest mortality with 20, 13 and 20% at dosages of 9.1, 7.0 and 5.3 mg/kg, respectively, whereas application of 11.9 mg/kg resulted in 100% mortality. T/C values of 18.3, 11.1 and 21.6%, respectively, demonstrated again high anticancer efficacy. Compared to the combination therapy with 5-FU and leucovorin (25 mg/kg each), p-N-acetyldinaline (7.0 mg/kg) was 4-fold more effective as indicated by T/C% values of 81.4 versus 21.9 at similar toxicity. In vitro, all three compounds were similarly active with IC50 concentrations between 1 and 2.2 micrograms/ml after 48 h of exposure and 0.6 to 1.6 micrograms/ml after 72 h of incubation. The MTT dye conversion assay correlated well with cell counts obtained by cell counting except for low dosages after short incubation periods when it stimulated cell proliferation. These results suggest that dinaline and its derivatives have clinical potential.

Animals↗
PubMed1995

Acute oral toxicity in rats of 3,7-bis-(4-trifluoromethylphenyl)-1,5,3,7-dioxadiazocane compared with 3,7-bis-(3-trifluoromethylphenyl)-1,5,3,7-dioxadiazocane and N,N'-oxydimethylenebis(2-trifluoromethylaniline).

The acute oral toxicity of 3,7-bis-(4-trifluoromethylphenyl)-1,5,3,7-dioxadiazocane (4-TFMPD) was compared with its 3-substituted isomer, 3,7-bis-(3-trifluoromethylphenyl)-1,5,3,7-dioxadiazocane (3-TFMPD) and with N,N'-oxydimethylenebis(2-trifluoromethylaniline) (N,N'-oxy-DM-bis (2-TFMA)). 4-TFMPD, 3-TFMPD, N,N'-oxy-DM-bis (2-TFMA) and their precursors (4-trifluoromethylaniline (4-TFMA), 3-trifluoromethylaniline (3-TFMA) and 2-trifluoromethylaniline (2-TFMA), respectively) were administered intragastrically to male Wistar rats at a dose of 0.12 mmol/kg body weight/day for three consecutive days and the resulting effects on haematological variables were determined. 4-TFMPD induced the highest methaemoglobinemia as compared with 3-TFMPD and N,N'-oxy-DM-bis (2-TFMA). Haemolytic anaemia with Heinz bodies, neutrophilia, lymphocytosis, enlargement of the spleen and enhanced production of granulocytes/macrophages from multipotential bone marrow cells (as determined by CFU-C test) were observed in animals treated with 4-TFMPD and 4-TFMA, whereas no such effects were observed in the other treatment groups. In conclusion, 4-substituted aniline derivatives exert special haematotoxicity on the red blood cells and induce leucocytosis, which differs from the effects of their 2- and 3-substituted congeners.

Administration, Oral↗
PubMed1995

Tumor induction and prophylaxis following different forms of intestinal urinary diversion in a rat model.

Eighty Wistar rats were randomized into two groups. In group 1 vesicosigmoidostomy with proximal colostomy was performed, in group 2, vesicosigmoidostomy. The total tumor incidence did not significantly (group 1 10/40, 25%; group 2 13/40, 32.5%). The tumor spectrum differed, with more adenocarcinomas in group 2 (11/40, 27.5% vs 4/40, 10%; P = 0.047) and urothelial carcinomas only in group 1 (5/40, 2.5%). One hundred and ten other Wistar rats were randomized into three groups. Animals in group A received vesicoileosigmoidostomy, group B, two-step vesicosigmoidostomy with initial separation of urine and the urocolonic anastomosis, group C, vesicosigmoidostomy. Significantly fewer adenocarcinomas were observed in group A (2/40, 5%) than in group B (16/40, 40%; P < 0.002) and group C (9/30, 30%; P < 0.007). These results indicate a similar cancer risk in all continent forms of urinary diversion, at least via colon. Ileal interposition seems to be an effective carcinoma prophylaxis following ureterosigmoidostomy. The proliferative instability at the urointestinal anastomosis is crucial for the pathogenesis and prophylaxis of this form of carcinogenesis, whereas urine seems to play only a minor role.

Adenocarcinoma↗