mitoguazone and Prostatic-Neoplasms

The prostate is a rich factory of polyamine production. In spite of this, the prostate is also able to accumulate polyamines from the circulation. Intracellular polyamine depletion has been observed to enhance the accumulation of diamines such as putrescine. This needs to be taken advantage of either as a means for imaging prostatic tumour spread to the lymph nodes or as a means of targeting toxins to the prostatic tumour. Putrescine is a small molecule that may prove difficult for use for synthesizing stable toxin derivatives that can take advantage of the targeting potential of the polyamine transporter. The cloning and sequencing characterization of the transporter is under way. When the prostatic transporter is identified, it will be possible to understand the role of the transporter in normal and cancerous prostatic cell growth and functioning and should serve to aid our understanding of how we can better optimize agents to use the transporter for delivery of antitumour agents.

Topics: Aziridines; Biological Transport; Cell Division; Dihydrotestosterone; Eflornithine; Guanidines; Humans; Male; Mitoguazone; Ornithine Decarboxylase; Polyamines; Prostate; Prostatic Neoplasms; Putrescine

Mitoguazone (methylglyoxal-bis(guanyl-hydrazone), MGBG) was studied by its first-pass mechanism in both cancer patients and experimental cancer models. It appears from the study that 90% of MGBG is cleared from the plasma within minutes. 24-h recovery in the urine, however, did not exceed 16% so that 84% of the drug seems to be bound to subcellular compartments. Tissue levels of MGBG in the normal prostate ranged higher than in experimental prostate cancer type 3327 M/G, i.e. enhanced clearance from cancer tissues: polyamine biosynthetic enzymes ornithine decarboxylase as well as S-adenosylmethionine decarboxylase are contrarily affected by MGBG.

Topics: Adenocarcinoma; Adenosylmethionine Decarboxylase; Animals; Carcinoma, Renal Cell; Cell Line; Cells, Cultured; Clinical Trials as Topic; Dose-Response Relationship, Drug; Drug Administration Schedule; Humans; Infusions, Parenteral; Kidney Neoplasms; Male; Mice; Mice, Inbred Strains; Mitoguazone; Ornithine Decarboxylase; Prostatic Neoplasms; Rats; Rats, Inbred Strains; Tissue Distribution

Mitoguazone (methylglyoxal bisguanylhydrazone, methyl-GAG or MGBG) is a synthetic polycarbonyl derivative with activity in patients with Hodgkin's and non-Hodgkin's lymphoma, head and neck cancer, prostate cancer, and esophageal cancer. Mitoguazone has also recently been documented to have activity in patients with AIDS-related lymphoma. Among anticancer drugs, mitoguazone has a unique mechanism of action via interference with the polyamine biosynthetic pathway. Polyamines stabilize DNA structure by non-covalent cross-bridging between phosphate groups on opposite strands. In addition, mitoguazone causes uncoupling of oxidative phosphorylation. In this study, the ability of mitoguazone to induce apoptosis by inhibiting the polyamine pathway was assessed in three Burkitt's lymphoma cell lines (Raji, Ramos and Daudi) and one prostate carcinoma cell line (MPC 3). Additional evaluations were performed in two human breast cancer cell lines (MCF7 with wild-type p53 and VM4K with mutated p53) to determine whether the p53 tumor suppressor gene was required for efficient apoptosis induction. The present study demonstrated that mitoguazone induces apoptosis in all the different human cancer cell lines tested in a concentration- and time-dependent way, and triggers a p53-independent programmed cell death in the human breast cancer MCF7 cell line.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Burkitt Lymphoma; Genes, p53; Humans; Male; Mitoguazone; Prostatic Neoplasms; Tumor Cells, Cultured

In this study the usefulness of the MTT assay for the quantitation of growth modulating effects on cultured prostate cancer lines (PC-3, PC-93, and LNCaP) was investigated. The MTT test is based on the enzymatic reduction of the tetrazolium salt MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide++ +] in living, metabolically active cells but not in dead cells. The reaction is carried out in situ in multiwell plates, and the reaction product, a purple-colored formazan soluble in dimethylsulfoxide, is measured colorimetrically, using a multiwell plate reader. Optimal test conditions were established for each of the cell lines used. With the hormone-sensitive cell line LNCaP, and stimulatory effect of the synthetic androgen R1881 was demonstrable by the MTT test. A sharp optimum occurred at a concentration of 10(-10) M R1881. Treatment of cells of either cell line with antineoplastic agents resulted in a dose-dependent reduction of MTT converting activity, reflecting the impaired survival of the drug-treated cells. Good correlations of the results obtained with the MTT-test, as compared with a thymidine incorporation assay or with direct DNA measurements, were observed. As the MTT test offers a high degree of precision and is easy to do, it is suitable for the purpose of (large-scale) chemosensitivity testing. Moreover, serial measurements might easily be performed in order to provide additional information on the mode of action of the drugs tested, i.e., to discriminate between cytostatic and cytotoxic drug effects.

Topics: Androgens; Cell Count; Cell Division; Coloring Agents; Drug Screening Assays, Antitumor; Eflornithine; Estrenes; Humans; Male; Metribolone; Mitoguazone; Oxidation-Reduction; Prostatic Neoplasms; Tetrazolium Salts; Thiazoles; Tumor Cells, Cultured

The effects of two inhibitors of ornithine decarboxylase activity, alpha-difluoromethylornithine (DMFO) and (2R,5R) 6-heptyne-2,5 diamine (HDA), and an inhibitor of S-adenosylmethionine decarboxylase, methylglyoxal bis-guanylhydrazone (MGBG), were tested on casein kinase activity and endogenous phosphorylation in the cytosol fractions of mouse thyroid and a rat prostate tumor model, Dunning R 3327 MAT LyLu subline. When tested at 5 mM, spermine, DMFO, HDA, and MGBG stimulated mouse thyroid casein kinase activity by 230%, 14%, 65% and 106%, respectively. Similar responses were observed in prostate tumor cytosol. In mouse thyroid cytosol, spermine stimulates 32P incorporation primarily into 3 proteins (MW: 107, 88, and 56 kDa). At 5 mM, MGBG partially reproduces the effects of spermine; HDA is less effective and DMFO is without effect. Similar effects were observed on 3 proteins in prostate tumor cytosol with molecular weights of 91, 41, and 32 kDa. These data provide additional support for the hypothesis that the observed synergistic inhibitory effect of DMFO and MGBG on cell growth may not be due solely to the inhibition of polyamine biosynthesis. Our findings suggest that MGBG-mediated reduction in the phosphorylation of casein kinase substrate should be considered as one locus of action.

Topics: Adenocarcinoma; Adenosylmethionine Decarboxylase; Alkynes; Animals; Antineoplastic Agents; Casein Kinases; Cytosol; Diamines; Eflornithine; Female; Male; Mice; Mitoguazone; Ornithine Decarboxylase Inhibitors; Phosphoproteins; Phosphorylation; Prostatic Neoplasms; Protein Kinases; Rats; Spermine; Thyroid Gland

Topics: Aged; Drug Evaluation; Humans; Male; Mitoguazone; Neoplasm Metastasis; Prostatic Neoplasms

Both alpha-difluoromethyl ornithine (DFMO) and methylglyoxal bis (guanylhydrazone) (MGBG) inhibit sequential enzymatic reactions in the pathway of polyamine biosynthesis. Since polyamines may be important factors in proliferation of cancer cells and DFMO combined with MGBG has shown synergistic cytotoxicity in an experimental prostatic tumor, we evaluated these agents in phase I clinical trial involving 5 patients with advanced, hormone-resistant prostatic cancer. Toxic reaction to combined DFMO and MGBG was dose-related and included nausea, fatigue, and diarrhea especially with the higher doses of MGBG. No therapeutic responses of significance were seen, but toxicity precluded adequate evaluation. Future Phase II studies of combined DFMO and MGBG should employ low, nontoxic doses of MGBG combined with evaluation of polyamine levels and inhibition of polyamine enzymatic activity to minimize toxicity.

Topics: Adenocarcinoma; Antineoplastic Combined Chemotherapy Protocols; Dose-Response Relationship, Drug; Drug Evaluation; Eflornithine; Humans; Male; Mitoguazone; Prostatic Neoplasms

Transplantable prostate adenocarcinoma were treated with polyamine biosynthetic inhibitors. alpha-difluoromethylornithine (alpha-DFMO), an inhibitor of ornithine decarboxylase and by s-methylglyoxal-bisguanylhydrazone (MGBG), an inhibitor of s-adenosylmethionine decarboxylase. The therapeutic regimen of 0.8-1.11 g/kg DFMO reduced the tumor growth by 40% whilst the combination with 10.5 mg/kg MGBG completely destroyed the prostate adenocarcinomas in the tumor-bearing animals. The polyamine content of spermidine and spermine in the cancerous tissues is significantly lower whereas the putrescine levels remain unchanged. The MGBG therapy distinctly stimulates the activity of ornithine decarboxylase and increases the putrescine concentration up to toxic levels. The application of alpha-DFMO prevented the toxic accumulation of putrescine and allowed higher doses of MGBG. Clinical trials with polyamine antimetabolites appeared useful due to pathological polyamine excretion of patients with metastatic prostate cancer. The therapy with 0.2-0.3 g/kg DFMO in patients with hormone-resistent prostate cancer and metastasis displayed a moderate anti-tumor activity following 2 months additional treatment. High levels of side effects, however, were registered and were similar to those of other cytotoxic compounds. A combined therapy with DFMO/MGBG in a patient with metastatic anaplastic prostate cancer did not improve the survival rate but showed regressive effects of the histological pattern.

Topics: Adenocarcinoma; Adenosylmethionine Decarboxylase; Animals; Antineoplastic Agents; Carboxy-Lyases; Carcinoma; Eflornithine; Estrogens; Humans; Male; Mitoguazone; Neoplasm Metastasis; Ornithine; Ornithine Decarboxylase Inhibitors; Prostatic Hyperplasia; Prostatic Neoplasms; Prostatitis; Putrescine; Rats; Spermidine; Spermine

The polyamine metabolism is pathologically changed in tumor tissues, and especially putrescine and spermidine demonstrate abnormally high values in kidney, bladder, and prostate cancer. The inductive processes which activate the biosynthetic polyamine enzymes in cancer are completely unknown. Of therapeutic interest is the fact that increased enzyme activities through irreversible inhibitors become significantly reduced, which consequently slows the tumor growth. Experimental therapy, especially in transplantable bladder and prostate cancer, displayed a 50% tumor destruction. In clinical studies using inhibitors of the polyamine biosynthesis, the dose had to be significantly reduced because of expressed toxicity. Additional investigations which tried a combination of reversible and irreversible inhibitors proved a similar antitumor activity, but less severe side effects.

Topics: Adenosylmethionine Decarboxylase; Antimetabolites, Antineoplastic; Carboxy-Lyases; Drug Combinations; Eflornithine; Enzyme Induction; Enzyme Inhibitors; Humans; Kidney Neoplasms; Male; Mitoguazone; Ornithine; Polyamines; Prostatic Neoplasms; Urogenital Neoplasms

Methylglyoxal-bis(guanylhydrazone) (MGBG), an inhibitor of polyamine synthesis, was administered to 35 patients with hormone-resistant advanced adenocarcinoma of the prostate in doses of 500 or 600 mg/m2 per week intravenously. Of 31 patients with bidimensional measurable soft-tissue lesions, 25 had an adequate trial, defined as four or more doses. Six (24%; 95% confidence limits, 8% to 32%) patients achieved a partial remission (greater than or equal to 50% reduction in tumor size) in soft-tissue disease. Response was noted to start after one to two doses and persisted for a median of three months (range, 1 to 4 months). Toxicity was tolerable, and significant myelosuppression was not observed. The lack of response in osseous metastases may be secondary to the short duration of remission or to the presence or inducibility of the enzyme ornithine decarboxylase in bone. Since some animal prostatic cancer tumor models are sensitive to cytotoxic drugs that produce polyamine inhibition, clinical trials of MGBG combined with other inhibitors of the polyamine pathway should be explored.

Topics: Adenocarcinoma; Aged; Drug Evaluation; Guanidines; Humans; Male; Middle Aged; Mitoguazone; Neoplasm Metastasis; Prostatic Neoplasms; Tomography, X-Ray Computed

The polyamines, putrescine, spermidine, and spermine, are fundamentally related to both normal and neoplastic cell proliferation. The prostate gland and prostatic tumors in man and rodents contain large amounts of polyamines. This suggests that inhibition of polyamine biosynthetic enzymes, ornithine decarboxylase (ODC) and S-adenosyl-methionine decarboxylase (SAMDC) may retard the growth of prostatic cancer. Since alpha-difluoromethylornithine (DFMO) and methylglyoxal-bis-guanylhydrazone (MGBG) are irreversible and competitive inhibitors of ODC and SAMDC, respectively, they were tested as single agents and in combination on a transplantable rapidly growing and hormone-resistant G subline of the Dunning R-3327 rat prostatic adenocarcinoma. Groups of rats bearing tumors were treated with various regimens of DFMO, MGBG, and DFMO plus MGBG, daily for 21 days. Analysis of differences in tumor growth between treatment groups and controls showed DFMO had no antitumor effect but was well tolerated, MGBG retarded growth rate significantly but resulted in drug deaths in over 50% of the animals, and the combination of DFMO and MGBG resulted in rapid decline in tumor growth rates after 5 to 9 days of treatment with reduced toxicity. At 21 days, or death, 38 of 60 (63%) rats had no viable tumor on histologic study, whereas tumor was present in each of the animals in the other groups. Alpha-difluoromethylornithine increased the intracellular uptake of MGBG and potentiated the antigrowth activity of MGBG on a hormone refractory rat prostatic tumor with less toxicity than MGBG alone.

Topics: Adenocarcinoma; Animals; Antineoplastic Combined Chemotherapy Protocols; Body Weight; Cell Line; Drug Synergism; Eflornithine; Guanidines; Humans; Male; Mitoguazone; Neoplasm Transplantation; Ornithine; Prostatic Neoplasms; Rats; Rats, Inbred Strains

The uptake of exogenously administered radiolabeled polyamines by a rat prostate-derived tumor line, the Dunning R3327 MAT-Lu, and various normal tissues was studied. Pretreatment of tumor cells in vitro with alpha-difluoromethylornithine (DFMO), a polyamine synthesis inhibitor, resulted in a markedly enhanced uptake of both [14C]putrescine and [14 C]spermidine. The in vitro uptake of [14C]putrescine by these cells was effectively inhibited by unlabeled spermine, spermidine, 1,8-diaminooctane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1,4-diaminopentane, and 1,4-diaminobutane, but less effectively by 1,4-diamino-2,3-butene and 1,4-diamino-2,3-butyne. The diamines, 1,3-diaminopropane and 1,2-diaminoethane, were ineffective in inhibiting [14C]putrescine uptake in vitro into the R3327 MAT-Lu cell line. When tumor-bearing animals were pretreated with DFMO or with DFMO and 5-alpha-dihydrotestosterone propionate, the tumor and prostate uptake of [14C]putrescine and [14C]-cadaverine was enhanced but not substantially increased in other tissues. In contrast to the in vitro results, spermidine and spermine were not enhanced substantially by DFMO pretreatment into any tissue, and their uptake into the tumor actually decreased. Ethylenediamine, which does not utilize the polyamine transport system, did not have its uptake increased into any tissue following DFMO pretreatment. The chemotherapeutic agent, methylglyoxal bis(guanylhydrazone), which utilizes the polyamine transport system for uptake into cells, exhibited uptake behavior different from that of the polyamines. Thus, methylglyoxal bis(guanylhydrazone) uptake into the tumor was not significantly increased or decreased by DFMO or by DFMO + 5-alpha-dihydrotestosterone propionate pretreatment, and only the ventral, but not the dorsal-lateral, lobe of the prostate showed increased uptake of methylglyoxal bis(guanylhydrazone) following DFMO + 5-alpha-dihydrotestosterone propionate pretreatment.

Topics: Animals; Antineoplastic Agents; Biological Transport; Carbon Radioisotopes; Cells, Cultured; Eflornithine; Guanidines; Male; Mitoguazone; Ornithine; Polyamines; Prostatic Neoplasms; Putrescine; Rats; Rats, Inbred Strains; Spermidine

Difluoromethylornithine (DFMO) and methylglyoxal-bis(guanyl-hydrazone) (MGBG), inhibitors of ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AMDC), respectively, were tested in two experimental prostatic cancer models. DFMO resulted in a reduction in tumor size in both the rapidly growing R-3327 rat prostatic adenocarcinoma (30.5 +/- 15 versus 61 +/- 9.5 in control animals) and the human DU-145 adenocarcinomas (1.7 ml versus 3.3 ml in control animals) in nude mice. MGBG was tested only in the rat tumor, where it induced a reduction of 22.9 +/- 9.5 ml versus 61 +/- 9.5 in control animals in tumor size but was highly toxic. Flutamide or 9-B-D-arabinofuranosyladenine (Ara-A) proved ineffective per se in reducing tumor growth of the human DU-145 or of the R-3327-G strain, respectively, but increased the efficacy of DFMO against the DU-145 tumor had a high level of ODC which was reduced by DFMO of by Ara-A; the R-3327 tumor had a low level of ODC which was too low to be decreased by DFMO.

Topics: Adenine; Adenocarcinoma; Adenosylmethionine Decarboxylase; Animals; Carboxy-Lyases; Eflornithine; Guanidines; Male; Mice; Mice, Nude; Mitoguazone; Ornithine; Ornithine Decarboxylase Inhibitors; Polyamines; Prostatic Neoplasms; Rats; Vidarabine

alpha-Difluoromethylornithine (DFMO) and methylglyoxal-bis-guanylhydrazone (MGBG), when administered simultaneously, inhibited growth and were highly toxic to the Dunning R 3327-G hormone-resistant prostatic adenocarcinoma transplanted into Copenhagen rats. Neither DFMO (2%) nor MGBG at a nontoxic dose (15 mg/kg) inhibited tumor growth, but total (47% early cure rate) or near total suppression of growth of established tumors was observed in rats receiving both treatments.

Topics: Adenocarcinoma; Animals; Body Weight; Cell Division; Drug Therapy, Combination; Eflornithine; Guanidines; Male; Mitoguazone; Ornithine; Polyamines; Prostatic Neoplasms; Rats; Rats, Inbred Strains

Inhibitors of polyamine synthesis were tested for therapeutic effectiveness on transplantable prostate cancer. Inhibition of either ornithine decarboxylase or S-adenosyl-L-methionine decarboxylase (AMDC) by alpha-difluormethylornithine (DFMO) or methylglyoxal-bis[guanylhydrazone] (MGBG), respectively, was associated with significant antitumor effect. The combination of DFMO with MGBG was not only more effective but no more toxic than MGBG alone. Combination of MGBG with 9-B-D-arabinofuranosyladenine, an indirect effector of SAMDC, failed to increase therapeutic effectiveness of MGBG.

Topics: Animals; Body Weight; Drug Therapy, Combination; Eflornithine; Guanidines; Male; Mitoguazone; Neoplasm Transplantation; Neoplasms, Experimental; Ornithine; Polyamines; Prostatic Neoplasms; Rats; Vidarabine