Improved performance of the anion-exchange centrifugation technique for studies with human infective African trypanosomes.
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Animals↗
Biomedical subjects
M R Berger
Publications and source records attributed to M R Berger.
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↗
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↗
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↗
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↗
Combination treatment based on metabolic effects of dinaline.
The human colon carcinoma cell line SW 707 was exposed for up to 72 h to the new antineoplastic agent 4-amino-N-(2'-aminophenyl)benzamide (GOE 1734, dinaline). Thereafter, uptake measurements with fluorodeoxy-[14C]glucose (FdGlc) were performed and cell-cycle fractions as well as adenine nucleotide pools were determined by flow cytometry and HPLC. One day after a 24 h exposure to 20-540 microM dinaline a 2.0-to 2.5-fold enhancement of FdGlc uptake was observed, and the values after 48-h or 72-h incubations showed a 2.5- to 3.5-fold or a 2.0-fold increase respectively. For all periods of exposure a diminished S phase (3%-71% of control) was found initially after incubation, demonstrating the antiproliferative effect of dinaline, with total recovery after 1 day. Adenine nucleotide pools were not diminished concomitantly. The enhanced FdGlc uptake caused by dinaline was the basis for choosing 2-deoxyglucose (dGlc) as the combination partner, which acts as an antimetabolite to enzymes involved in glucose metabolism. Several combinations of dinaline and dGlc were analyzed for their effects on growth inhibition. Almost 50% additional decrease in cell number as compared to monotherapy with dinaline was found after coexposure to 12 mM dGlc and 20 microM dinaline 24 h after incubation. Similar effects were observed 2 days after incubation with the two drugs. After 3 days, the cell numbers reached monotherapy levels. Since the cytostatic effect of dinaline could be enhanced by dGlc although incubation with dGlc alone caused no changes in cell number, the combined effect of both agents is synergistic. These results imply that dinaline might have applications in combination treatment in vivo.
Adenine Nucleotides↗
Pharmacokinetic behavior and antineoplastic activity of liposomal hexadecylphosphocholine.
Hexadecylphosphocholine (HePC) shows remarkable antineoplastic efficacy in Sprague-Dawley rats bearing methylnitrosourea-induced mammary carcinoma. Unfortunately, this is accompanied by detrimental side effects that include gastrointestinal damage, body weight loss, and thrombophlebitis after i.v. injection, which has precluded the use of the HePC in humans, where nausea and vomiting can occur at noneffective dose levels. We have developed small unilamellar vesicles (SUVs) composed of HePC, cholesterol, and 1,2-dipalmitoyl-sn-gly-cero-3-phosphoglycerol, which can be given p.o. and i.v. In contrast to the free drug, the toxicity of liposomal HePC is shown to be greatly reduced, and there is no risk of thrombophlebitis. Single administration of equimolar HePC doses results in differing pharmacokinetic values for free HePC (p.o.) and HePC-SUVs (p.o., i.v.).
Administration, Oral↗
Conference on carcinogenic risk factors in the occupational environment (Krebserzeugende Gefahrstoffe in der Arbeitsumwelt). Frankfurt/Main, October 1993.
In this summary, J. Konietzko (Mainz) stressed the exceptional position of occupational cancer, which is due to the long latent period between exposure to specific carcinogens and cancer manifestation. Obviously, this long latent period of years to decades poses problems in the search for the etiology of occupational cancer. Three methodological areas are instrumental in overcoming these problems. They include epidemiological investigations, in vitro experiments and animal experiments, which have to complement each other. A highly important area within the aetiological research is the field of syncarcinogenesis. Up to now, some research on combined effects has been done, but this field urgently needs further efforts and promotion since the threat of more than additive carcinogenic effects can be ruled out or prevented only after the necessary knowledge has been gathered from properly conducted basic research. Within the discussion of occupational cancer, three areas have to be discriminated; they relate to cancer as an occupational disease, as a problem within the insurance laws, and as a risk that requires preventive measures. Its acknowledgement as an occupational disease is based on strict legal preconditions that limit any generosity. Such a procedure is too reserved, however, as far as preventive measures are concerned. In this area, more generous criteria are required, which do not only result from scientific procedures. Prevention is subject to a clear ranking; primary prevention, i.e. the elimination of carcinogens from the workplace, has priority. If the elimination of occupational hazards is impossible, a quantitative risk assessment that takes account of synergistic carcinogenic effects can help to set priorities. The impossibility of a complete primary prevention necessitates secondary and tertiary prevention, which correspond to early diagnosis and follow-up management of occupational cancer. Each of these areas needs continued attention.
Carcinogens↗
Structure-activity relationships of four anti-cancer alkylphosphocholine derivatives in vitro and in vivo.
This study was carried out to investigate whether structure-activity relationships of alkylphosphocholines, a new group of anti-neoplastic agents, which had been detected in methylnitrosourea(MNU)-induced rat mammary carcinoma, can be transferred to in vitro systems. Therefore, the anti-neoplastic activity of 4 alkylphosphocholines (APCs) was compared in 6 tumor cell lines in vitro and in MNU-induced rat mammary carcinoma in vivo. The in vitro system consisted of 2 rat mammary-carcinoma-derived cell lines (1/C2 and 1/C32), as well as 2 human mammary-gland (MDA-MB-231 and MCF-7)- and gastrointestinal tract (HT-29 and KB)-derived tumor cell lines. As assessed by both cell counting and MTT-assay, the ranking of concentrations effecting 50% growth inhibition (IC50) was parallel in all cell lines for octadecylphosphocholine (18:0-PC), octadecenyl-(trans-9.10)-phosphocholine (t-18:1-PC) and octadecenyl-(cis-9.10)-phosphocholine (c-18:1-PC). Only hexadecylphosphocholine (16:0-PC) differed in its activity, being least active in 1/C2, 1/C32 and MDA-MB-231 cells, moderately active in KB and MCF-7 cells, and most active in HT-29 cells. The IC50 concentrations of APCs in the 2 rat mammary carcinoma cell lines significantly correlated with dosages effecting a 50% tumor growth delay in vivo. Remarkably, the 2 gastrointestinal cell lines were more sensitive to APC exposure than the mammary-carcinoma cell lines. In all cell lines except KB cells, growth-stimulation effects were seen in the concentration range preceding the anti-proliferative activity; in vivo, however, no accelerated cancer growth was observed. The in vitro system failed to describe the superior therapeutic ratio of c-18:1-PC, as assessed in vivo, because it does not take the relative sensitivity of tumor vs. normal cells into account. Complementary in vivo trials are therefore indispensable for a final evaluation. Comparison of the 2 in vitro assays shows good agreement of the interrelationship of IC50 values, those obtained by MTT assay being on average 25% higher than those obtained from cell counting.
Animals↗
Hexadecylphosphocholine differs from conventional cytostatic agents.
Alkylphosphocholines, and especially their main representative hexadecylphosphocholine (HPC), show high anticancer activity in methylnitrosourea (MNU)-induced autochthonous rat mammary carcinoma. The regression of MNU-induced rat mammary carcinoma during HPC treatment can be evaluated by computed tomography and sonography. This allows a noninvasive monitoring of therapy in vivo (tumor size, morphology, and blood supply). Both diagnostic modalities can show a rapid concentric decrease in tumor volume as well as the appearance of cystic, scarry, and necrotic areas in the tumor tissue as a result of HPC treatment. In addition, prior to, during and after therapy tumor perfusion can be assessed by color Doppler sonography in vivo. A more than 4-fold difference in HPC efficacy was observed when the colony growth of explanted MNU-induced mammary carcinoma cells was measured in the methylcellulose colony assay (IC50 = 180 mumol HPC/l) and the Hamburger Salmon colony assay (IC50 = 740 mumol HPC/l). In the latter assay, growth of concomitantly seeded untransformed cells, especially of fibroblasts, is much lower than in the methyl-cellulose colony assay. We therefore assume that the antitumor efficacy of HPC against MNU-induced mammary carcinoma is enhanced by neighboring cells such as fibroblasts. Cell culture experiments with the three MNU-induced rat mammary carcinoma cell clones 1-C-2, 1-C-30, and 1-C-32 revealed IC50 values in the range of 50-70 mumol HPC/l. The volume of 1-C-2 cells increased up to 4-fold after 72 h of permanent exposure to 100 mumol HPC/l, a concentration that completely inhibited proliferation of tumor cell numbers without being cytotoxic. Nucleotide triphosphate levels dropped significantly after 24 h and were slowly restored in spite of continued exposure. After 72 h, they nearly reached those levels observed in plateau-phase cells. This suggests that HPC-induced growth inhibition has similarities with physiologically occurring growth arrest. Finally, replication of RNA viruses and DNA viruses was suppressed 30-fold and 7-fold, respectively, at low concentrations of HPC (12 mumol/l), which caused no or negligible growth inhibition in the virus-harboring cells, thus demonstrating specific antiviral activity of HPC. From these observations we conclude that HPC differs in many important aspects from conventional cytostatic agents and is certainly worth following-up in further investigations.
Animals↗
Antiproliferative activity of retinoic acid and some novel retinoid derivatives in breast and colorectal cancer cell lines of human origin.
Antiproliferative activities of all-trans-retinoic acid (RA, CAS 302-79-4) and some retinoid derivatives (all-trans-retinyl-beta-D-glucuronide (RYG), methyl-(1-O-retinoyl-beta-D-glucopyranoside) uronate (MRG), all-trans-retinoic acid beta-D-galactopyranosyl ester (RGA), and all-trans-retinoic acid beta-D-glucopyranosyl ester (RGU)) were determined by microculture tetrazolium assay (MTT assay) and cell counting by Coulter Counter (CC) in breast (MCF7, MDA MB 231) and colon (SW 948) cancer cell lines of human origin. RA, MRG, RGU, and RGA (5, 25 mumol/l) were significantly more growth-inhibitory in MCF7 cells, which are known to be cellular retinoic acid-binding protein (cRABP) and cellular retinol binding protein (cRBP) positive, than in MDA MB 231 cells which are cRABP and cRBP negative. RYG was active only in MDA MB 231 cells. RA, MRG, RGA and RGU (25 mumol/l) stimulated the proliferation of SW 948 cells as determined by CC, whereas the MTT assay indicated an inhibition of cell growth.
Breast Neoplasms↗
Nucleotide preparation from cells and determination of nucleotides by ion-pair high-performance liquid chromatography.
Procedures for the analysis of cellular purine and pyrimidine nucleotides are described. The commonly used perchloric acid and especially the trichloroacetic acid methods for nucleotide extraction interfere with ion-pair high-performance liquid chromatography, but we have developed such a system for the separation and determination of major cellular nucleotides in biological matrices, including tri-, di-, monophosphates, cAMP, cGMP, NAD, NADP, UDP-glucose and UDP-galactose. Compared with perchloric acid extraction, no degradation of the nucleotide standards used was observed with respect to triphosphates and other relatively unstable nucleotides. Cellular nucleotides were extracted by lysing cells in a hypotonic buffer containing an ion-pair reagent (tetrabutylammonium hydrogen-sulphate) to decrease enzymic degradation of nucleotides in combination with ultrafiltration of the cell lysate to remove compounds of higher molecular mass, for example enzymes. This method is a simple and reproducible procedure for investigating nucleotide pools in cells.
Animals↗
Alkylphosphocholines: influence of structural variation on biodistribution at antineoplastically active concentrations.
Hexadecylphosphocholine (HPC) and octadecylphosphocholine (OPC) show very potent antitumor activity against autochthonous methylnitrosourea-induced mammary carcinomas in rats. The longer-chain and unsaturated homologue erucylphosphocholine (EPC) forms lamellar structures rather than micelles, but nonetheless exhibits antineoplastic activity. Methylnitrosourea was used in the present study to induce autochthonous mammary carcinomas in virgin Sprague-Dawley rats. At 6 and 11 days following oral therapy, the biodistribution of HPC, OPC and EPC was analyzed in the serum, tumor, liver, kidney, lung, small intestine, brain and spleen of rats by high-performance thin-layer chromatography. In contrast to the almost identical tumor response noted, the distribution of the three homologues differed markedly. The serum levels of 50 nmol/ml obtained for OPC and EPC were much lower than the value of 120 nmol/ml measured for HPC. Nevertheless, the quite different serum levels resulted in similar tumor concentrations of about 200 nmol/g for all three of the compounds. Whereas HPC preferably accumulated in the kidney (1 mumol/g), OPC was found at increased concentrations (400 nmol/g) in the spleen, kidney and lung. In spite of the high daily dose of 120 mumol/kg EPC as compared with 51 mumol/kg HPC or OPC, EPC concentrations (100-200 nmol/g) were low in most tissues. High EPC concentrations were found in the small intestine (628 nmol/g). Values of 170 nmol/g were found for HPC and OPC in the brain, whereas the EPC concentration was 120 nmol/g. Obviously, structural modifications in the alkyl chain strongly influence the distribution pattern of alkylphosphocholines in animals. Since EPC yielded the highest tissue-to-serum concentration ratio in tumor tissue (5.1) and the lowest levels in other organs, we conclude that EPC is the most promising candidate for drug development in cancer therapy.
Animals↗
Activity of two platinum-linked phosphonic acids against autochthonous rat colorectal cancer as well as in two human colon-cancer cell lines.
Two new platinum-containing phosphonate compounds, cis-diammine[nitrilotris(methylphosphonato)(2-)- O1,N1]platinum(II) (AMDP) and cis-cyclohexane-1,2-diamine[nitrilotris(methylphosphonato) (2-)-O1,N1]platinum(II) (DADP) were investigated in acetoxy-methyl-methylnitrosamine-induced autochthonous colorectal rat adenocarcinoma in vivo as well as in two human colon-cancer cell lines (SW707 and SW948) in vitro. In the in vivo model, the two compounds were given i.v. at doses of 8 and 13 mg/kg as well as p.o. at 16 and 26 mg/kg twice a week for 10 weeks, respectively. AMDP produced more intensive toxicity at both doses but showed higher antitumour activity only following i.v. administration. On the other hand, DADP caused significant tumour-growth inhibition after both modes of application, but as it produced only low toxicity, its use should be favoured. The in vitro assays were performed using two cell lines derived from human colorectal adenocarcinomas. According to the microculture tetrazolium test (MTT) AMDP (IC50, 34 and 59 microM in SW707 and SW948, respectively) was more effective than DADP (IC50, 412 and 660 microM in SW707 and SW948, respectively) in inhibiting cell growth. Based on cell counts AMDP (IC50, 8 and 11 microM in SW707 and SW948, respectively) and DADP (IC50, 266 and 285 microM in SW707 and SW948, respectively) showed more intensive antiproliferative efficacy as determined by the Coulter Counter method vs the MTT assay. The promising activities of these new platinum-linked phosphonic acids in autochthonous rat colorectal carcinoma and in human colorectal cancer cell lines warrant further investigations of compounds of this class to elucidate their role in the treatment of colorectal cancer.
Adenocarcinoma↗
Assessment of antineoplastic agents by MTT assay: partial underestimation of antiproliferative properties.
In the present study a slightly modified MTT assay was used in conjunction with cell counting to determine the antiproliferative efficacy of N-(2-chloroethyl)-N-nitroso-N'-2-hydroxyethylurea (HECNU), vinblastine, and hexadecylphosphocholine (HPC) in a panel of six tumor cell lines. This panel consisted of two human (MDA-MB231, MCF-7) and two rodents (1/C2, 1/C32) mammary-carcinoma cell lines as well as of two tumor cell lines of gastrointestinal origin (HT-29, KB). It was shown that the use of acid isopropanol as a solvent of the formazan crystals produced correlations between cell number and absorption that were as good as, if not better than, those seen after dimethylsulfoxide (DMSO) application. The optimal period of incubation with the MTT dye was 2 h. A comparison of the antiproliferative activity of HECNU revealed that the HT-29 cell line was most resistant [50% inhibition concentration (IC50), 138.7 mumol/l], followed by MCF-7 cells (IC50, 127.7 mumol/l), whereas MDA-MB231 cells showed the highest sensitivity (IC50, 6 mumol/l). Vinblastine induced the highest (MCF-7 cells; IC50, 0.68 nmol/l) and the lowest (1/C2 cells; IC50, 7.69 nmol/l) degrees of growth inhibition in cell lines derived from mammary carcinoma. This contrasted with the activity of HPC, which was considerably less effective in the four mammary-carcinoma cell lines (IC50 from 29.4 to 69.9 mumol/l) than in the two cell lines of gastrointestinal origin (IC50, 1.9 and 3.1 mumol/l). Interestingly, treatment with HPC stimulated the growth of 1/C32 cells in the lower dose range. After treatment with HECNU, the average IC50 value determined in the MTT assay was 2.4-fold that disclosed by cell counting, whereas the average values found for HPC and vinblastine by both methods corresponded fairly well, with the respective values obtained using the MTT assay being only 26% and 14% higher than those measured by cell counting. A dose-dependent increase in the mean size of MCF-7 cells was observed after exposure to HECNU, which--if taken into account--considerably reduced underestimation of this parameter by the MTT assay. No variation in cell size was noted following treatment with HPC and vinblastine. Thus, depending on the antitumor agent used, the MTT assay can result in slight or even considerable underestimation of the antitumor efficacy of certain compounds and may need correction by consideration of the effect of the drugs on cell size.
Animals↗
Antineoplastic activity of three ruthenium derivatives against chemically induced colorectal carcinoma in rats.
The antineoplastic activity of the ruthenium complexes trans-imidazolium[tetracholorobisimidazole-ruthenate(III)], HIm(RuIm2Cl4), trans-indazolium-[tetrachlorobis(1H-indazole)ruthenate (III, N2)], HInd [RuInd2Cl4(N2)], and trans-indazolium[tetrachloro-bis(2H-indazole)ruthenate(III,N 1)], HInd[RuInd2Cl4-(N1)] was assessed in acetoxymethylmethylnitrosamine-induced autochthonous colorectal carcinomas of Sprague-Dawley rats. The model is not sensitive to clinically established antineoplastic agents, including cisplatin. An exception is the combination therapy with 5-fluorouracil/leucovorin, which shows moderate activity against the tumour model. In contrast to this general trend, the new substances were all active against this tumour. HIm(RuIm2Cl4) was very effective at all dosages applied (7.5 mg/kg, 5.3 mg/kg, and 3.8 mg/kg), as indicated by percentage treated/control (T/C values of 23%, 34.5%, and 44%. Toxicity was considerable as shown by a body weight change of -30%, -19%, and -9%. Nevertheless, the medium dose seems to be the optimum in terms of mortality (0% vs 15% in the control group), whereas at the highest dose, mortality increased as a result of substance toxicity, and at the lowest dose mortality increased through tumor growth combined with substance toxicity. HInd[RuInd2Cl4(N2)] showed high efficacy at the highest dosage of 13 mg/kg, reaching a T/C value of 27% combined with 0% mortality versus 15% in the control group. In equimolar dosages (10 mg/kg, 7.1 mg/kg and 5.1 mg/kg), the compound is not as active as HIm-(RuIm2Cl4), as indicated by T/C values of 50.2%, 45.7%, and 38.6%. HInd[RuInd2Cl4(N1)] was slightly but not significantly better than HInd[RuInd2Cl4(N2)] at a dosage of 7.1 mg/kg and is advantageous over combination therapy with 5-fluorouracil and leucovorin (20/20 mg/kg) in terms of efficacy (T/C = 37.6% versus 44.7%) and mortality (6% versus 33.3%).
Animals↗
Influence of reducing luxury calories in the treatment of experimental mammary carcinoma.
The aim of this study was to investigate the influence of dietary calorie intake at three different fat levels on (a) the growth of established methylnitrosourea (MNU)-induced mammary carcinoma, (b) the reappearance of mammary carcinomas after surgical removal, and (c) the growth of manifest lesions in animals treated with the cytostatic agent hexadecylphosphocholine (HPC). A reduction of calories by 30% significantly inhibited tumour growth of manifest mammary carcinomas in rats, without having a negative influence on body weight gain. After chemotherapeutic treatment no significant dietary influence was observed besides the high antineoplastic efficacy of HPC, but when feeding calorically restricted diets to surgically treated animals the number of reappearing tumours was considerably smaller (P = 0.06) than after feeding the diets ad libitum. The fat content of the diets did not influence the growth of manifest mammary carcinomas. No significant dietary effects were exerted on oestradiol or testosterone levels in untreated tumour bearing animals. An elevation of oestradiol levels was observed when animals were subjected to HPC and fed a high calorie diet. An elevation of testosterone levels was assessed after surgical treatment of the rats, irrespective of fat content and calorie level. Our results suggest that a reduction of calories can inhibit growth of manifest mammary carcinomas and has impeding effects on tumour development after surgical removal. After effective chemotherapeutic treatment the additional influence of dietary changes was of less relevance. Furthermore, our data do not establish any association between growth inhibition of mammary tumours, caused by the mild caloric restriction, and altered oestradiol or testosterone production.
Animals↗
Antitumor activity of alkylphosphocholines and analogues in methylnitrosourea-induced rat mammary carcinomas.
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Animals↗