melphalan and carbogen

Many anticancer drugs require oxygen to be cytotoxic or are selectively cytotoxic toward cells under oxygenated conditions. The effects of the dilute perfluorochemical emuolsion Fluosol with a wide variety of chemotherapeutic agents have been explored; however, it has not been possible to determine the optimal level of circulating perfluorochemical emulsion with anticancer drugs because the volume of Fluosol that may be administered is limiting. Using a new concentrated perfluorochemical emulsion, a wide range of perfluorochemical doses has been examined in combination with melphalan, cyclophosphamide and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in the FSaIIC fibrosarcoma. When the perfluorochemical emulsion was administered by injection i.v. just prior to the injection of melphalan (10 mg/kg), cyclophosphamide (150 mg/kg) or BCNU (50 mg/kg), the greatest tumor growth delays were obtained with dosage levels between 4 g and 12 g of the perfluorochemical perfluorooctyl bromide/kg. With each drug the greatest tumor growth delays were obtained when the drug was prepared in the emulsion and the combination injected i.v. In each case, each dose of drug was followed by 6 h of breathing carbogen. The addition of the perfluorochemical emulsion/carbogen breathing to treatment with melphalan, BCNU or cyclophosphamide resulted in significant increases in the killing of tumor cells by these drugs without a concomitant increase in toxicity to bone marrow granulocyte/macrophage-colony-forming units. In each case, preparing the drug in the perfluorochemical emulsion was most effective. These results indicate that clinical trial of this perfluorochemical emulsion/carbogen breathing in combination with cancer chemotherapy may be warranted.

Topics: Administration, Inhalation; Alkylating Agents; Animals; Antineoplastic Combined Chemotherapy Protocols; Carbon Dioxide; Carmustine; Cell Survival; Cyclophosphamide; Drug Administration Schedule; Drug Synergism; Emulsions; Fibrosarcoma; Fluorocarbons; Hematopoietic Stem Cells; Hydrocarbons, Brominated; Male; Melphalan; Mice; Mice, Inbred C3H; Neoplasm Transplantation; Oxygen; Tumor Cells, Cultured

Polymerized bovine hemoglobin solutions (PBHS) are being actively investigated as blood substitutes. In studies analogous to those we conducted with perfluorochemical emulsions/carbogen, we have examined the effect of PBHS +/- carbogen (95% O2, 5% CO2) breathing on the antitumor efficacy of melphalan, cyclophosphamide, N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU) and cis-diamminedichloroplatinum(II) (cis-platin). The tumor growth delay of the FSaIIC fibrosarcoma treated with melphalan (10 mg/kg), cyclophosphamide (150 mg/kg), cisplatin (10 mg/kg) and BCNU (15 mg/kg) was increased about 2.2-fold, about 2.1-fold, about 1.2-fold and about 1.5-fold, respectively, when PBHS (12 mg/kg) was administered i.v. before each drug was injected i.p. The tumor growth delay produced by each drug was further increased when carbogen breathing for 6 h was allowed after administration of the drug and PBHS. In tumor cell survival experiments 24 h following drug treatment, the addition of PBHS increased the tumor cell killing of both melphalan and cyclophosphamide by about a factor of 10 at the lowest doses of each drug tested (10 mg/kg for melphalan and 100 mg/kg for cyclophosphamide) compared to the drug alone. However, at higher drug doses this effect was lost. The toxicity of each antitumor agent toward bone marrow (granulocyte/macrophage-colony-forming units) was increased 2- to 3-fold by the combined treatment. These results suggest that use of PBHS +/- carbogen breathing may add significantly to the efficacy of antitumor alkylating agents, however, the in vivo/in vitro data suggest that there will be increased bone marrow toxicity with this approach. This needs to be taken into account in the design of clinical trials.

Topics: Alkylating Agents; Animals; Carbon Dioxide; Carmustine; Cattle; Cisplatin; Cyclophosphamide; Drug Synergism; Fibrosarcoma; Hemoglobins; Male; Melphalan; Mice; Mice, Inbred C3H; Oxygen

Tumor cell survival assay in the FSaIIC murine fibrosarcoma demonstrated that when the modulator Fluosol-DA (0.3 ml; 12 ml/kg i.v.) was administered just prior to an alkylating agent plus carbogen breathing for 6 h or the modulator etanidazole (1 g/kg i.p.) was administered just prior to an alkylating agent, the combination treatment produced significantly more tumor cell killing across the dosage range of each alkylating agent tested compared with the alkylating agent alone. Each alkylating agent produced a dose-dependent log-linear tumor cell survival curve. There was an increase in tumor cell killing of 5-10-fold when either Fluosol-DA/carbogen or etanidazole was added to treatment with the alkylating agent. For cis-diamminedichloroplatinum(II) (CDDP) and N,N',N''-triethylenethiophosphoramide, the modulators used in combination increased tumor cell killing by only 2-3-fold over that obtained with a single modulator, but for the other alkylating agents, tumor cell killing was increased by 10-50-fold when the combination of modulators was used. Bone marrow granulocyte-macrophage colony-forming unit survival assays showed that the combination of modulators with the alkylating agents resulted in only small increases in bone marrow toxicity of the alkylating agents except for N,N',N''-triethylenethiophosphoramide and L-phenylalanine mustard (L-PAM), for which the toxicity to the bone marrow granulocyte-macrophage colony-forming unit was increased by 5-10-fold compared with the alkylating agents alone. The Hoechst 33342 dye diffusion defined tumor cell subpopulation assay, also in the FSaIIC tumor, demonstrated that the combination of modulators increased the toxicity of CDDP, cyclophosphamide, L-PAM, and 1,3-bis(2-chloroethyl)-1-nitrosourea by 9-55-fold compared with the alkylating agent alone in both the bright (euxoic-enriched) and dim (hypoxic-enriched) cells. For each alkylating agent except 1,3-bis(2-chloroethyl)-1-nitrosourea, the increase in tumor cell killing was greater in the dim cells than in the bright cells. Finally, tumor growth delay studies in both the FSaIIC tumor and the EMT-6 murine mammary adenocarcinoma confirmed that the combination of modulators significantly increased the tumor growth delay caused by CDDP, carboplatin, cyclophosphamide, N,N'N"-triethylenethiophosphoramide, L-PAM, and 1,3-bis(2-chloroethyl)-1-nitrosourea. The greatest increases (4-5-fold) were observed for carboplatin and L-PAM in the FSaIIC tumor and CDDP and cycloph

Topics: Alkylating Agents; Animals; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow; Carbon Dioxide; Carboplatin; Carmustine; Cell Survival; Colony-Forming Units Assay; Cyclophosphamide; Dose-Response Relationship, Drug; Drug Combinations; Drug Synergism; Etanidazole; Fibrosarcoma; Flow Cytometry; Fluorocarbons; Hydroxyethyl Starch Derivatives; Mammary Neoplasms, Experimental; Melphalan; Mice; Nitroimidazoles; Organoplatinum Compounds; Oxygen; Radiation-Sensitizing Agents; Thiotepa

Adding Fluosol-DA and carbogen breathing to treatment with various anticancer drugs can result in a significant enhancement of tumor growth delay compared to the drug and air breathing. The optimal conditions for tumor response depend upon the drug, oxygenation level and duration, and perfluorochemical emulsion dosage. In this study, representative chemotherapeutic agents from several classes were tested in a tumor growth delay assay in combination with various doses of Fluosol-DA under conditions of normal aeration, carbogen breathing either for 1-2 hours or 6 hours, or with hyperbaric 100% oxygen (3 atmospheres) breathing for 1 hour to determine whether the antitumor activity of these drugs would be improved.

Topics: Animals; Antineoplastic Agents; Bleomycin; Breast Neoplasms; Carbon Dioxide; Cyclophosphamide; Dose-Response Relationship, Drug; Doxorubicin; Drug Combinations; Fibrosarcoma; Fluorocarbons; Fluorouracil; Humans; Hydroxyethyl Starch Derivatives; Male; Melphalan; Methotrexate; Mice; Mice, Inbred C3H; Mice, Nude; Neoplasm Transplantation; Neoplasms; Organoplatinum Compounds; Oxygen; Tumor Cells, Cultured

Fluosol-DA with carbogen (95% oxygen and 5% carbon dioxide) breathing can increase the efficacy of melphalan. Addition of Fluosol-DA to treatment with melphalan leads to a greater increase in tumor growth delay under conditions of air breathing and carbogen breathing than does the fat emulsion Intralipid. The ability of melphalan to kill tumor cells increased with dose over the range of drug examined. At the lower doses of drug there is some increase in tumor cell killing seen with the addition of carbogen breathing or Fluosol-DA and air breathing; however, at the highest dose of the drug this difference disappeared. Throughout the melphalan dosage range examined there is approximately 1 log greater tumor cell kill observed with the addition of Fluosol-DA and carbogen breathing compared to the drug treatment alone. There was no significant difference in the survival of bone marrow cells under any of the treatment conditions. Fluosol-DA itself with air or carbogen breathing produced no detectable cross-links in DNA from tumors treated in vivo. The cross-linking factors for melphalan with air or carbogen breathing and for melphalan plus Fluosol-DA and air breathing were similar; when carbogen breathing was added to the treatment combination, the cross-linking factor increased almost 3-fold. When melphalan was dissolved in Fluosol-DA, the melphalan moved quickly into the lipophilic perfluorochemical particles so that after 1 h 60% of the drug was in the perfluorochemical layer. At 24 h, 85-90% of the melphalan was sequestered in the perfluorochemical particles. The pharmacokinetics of [14C]melphalan alone, [14C]melphalan plus Fluosol-DA, and [14C]melphalan prepared in Fluosol-DA were studied in several tissues of FSaIIC fibrosarcoma-bearing mice. In general, the tissue absorption and distribution t1/2s for melphalan were shortened in the presence of Fluosol-DA (except for kidneys). Shifting the t1/2s for absorption and distribution to shorter times produces a much sharper and earlier peak in the drug exposure of the tumor. Fluosol-DA provides a relatively nontoxic means of increasing oxygen delivery to tumors and a therapeutically meaningful way of improving melphalan antitumor activity.

Topics: Animals; Bone Marrow; Carbon Dioxide; Cell Survival; DNA Damage; Drug Combinations; Fat Emulsions, Intravenous; Fluorocarbons; Hydroxyethyl Starch Derivatives; Kinetics; Male; Melphalan; Mice; Oxygen; Sarcoma, Experimental; Solubility; Tissue Distribution

The cytotoxicity of melphalan toward exponentially growing FSaIIC fibrosarcoma cells under hypoxia, normal aeration, hyperoxygenation, and stationary phase normally oxygenated cells was examined. Through 4 logs of cell kill by melphalan, there was no difference in survival of FSaIIC cells under any of the four conditions. In the fifth and sixth logs of cell kill, melphalan was most cytotoxic toward normally aerated cells. DNA alkaline elution was performed in FSaIIC cells treated for 1 h with melphalan under the various atmospheres. Both upon immediate elution and after a 6-h delay period the greatest number of DNA cross-links were formed in the normally oxygenated cells. Tumor growth delay studies of the FSaIIC fibrosarcoma treated with melphalan were performed under four levels of oxygenation. From air breathing to 100% oxygen at 3 atm, the tumor growth delay produced by melphalan increased from about 3 days to about 9 days. With the addition of Fluosol-DA, there was an increase in tumor growth delay by melphalan from about 6.5 days with air breathing to about 13 days with 100% oxygen at 3 atm (1 h). When FSaIIC fibrosarcoma tumors were treated with melphalan, and tumor cell survival was measured by colony formation in culture, increasing doses of melphalan produced increasing levels of tumor cell kill in a relatively log linear manner. The addition of Fluosol-DA to treatment with melphalan produced approximately 1 log greater tumor cell kill than melphalan and air breathing under the various oxygenation conditions. There was approximately a 4-fold increase in toxicity to bone marrow granulocyte-macrophage colony-forming units under both extended carbogen breathing conditions (6 h) and hyperbaric oxygenation conditions (100% oxygen, 1 h, 3 atm). The response of the spleen to these various treatment regimens appeared to be immediate and shortlived. Necrotic cells were seen on day 1 posttreatment, with a substantial reduction by day 4 posttreatment. Mitotic figures were essentially absent from the liver on day 1 posttreatment, but by day 4 were significantly increased in treatment groups receiving Fluosol-DA, with the largest number seen in the melphalan/Fluosol-DA with carbogen-breathing group. In conclusion, Fluosol-DA and 1 h of carbogen breathing significantly increases the antitumor activity of melphalan without a concomitant increase in normal tissue toxicity. Although increasing the oxygenation level increased the response of the tumor, normal tiss

Topics: Animals; Carbon Dioxide; Cell Survival; Cells, Cultured; Drug Combinations; Drug Synergism; Fluorocarbons; Hydroxyethyl Starch Derivatives; Male; Melphalan; Mice; Neoplasms, Experimental; Oxygen; Spleen

The addition of Fluosol-DA carbogen breathing to melphalan treatment of the FSa-IIC fibrosarcoma was assessed by tumor growth delay and cell survival assays. Melphalan (10 mg/kg) administered intraperitoneally (i.p.) was preceded by Fluosol-DA (0.3 ml) administered intravenously (i.v.) and followed by 1 hr of carbogen breathing; this resulted in a tumor growth delay of 9.5 +/- 1.4 days or an approximately 3-fold increase compared to melphalan alone. Melphalan produced about 1.7 logs of cell killing; neither carbogen breathing nor Fluosol-DA pretreatment altered the cell killing observed. There was a 10-fold increase in tumor-cell killing when Fluosol-DA was administered immediately prior to melphalan administration followed by carbogen breathing for 1 hr. Density gradient separation identified a population of denser FSa-IIC cells which showed increased sensitivity to melphalan after Fluosol-DA administration. There was no additional toxicity to bone marrow as measured by CFU-GM with the combination of melphalan/Fluosol-DA/O2 compared to melphalan alone.

Topics: Animals; Carbon Dioxide; Cell Survival; Drug Combinations; Drug Synergism; Fluorocarbons; Hematopoietic Stem Cells; Hydroxyethyl Starch Derivatives; Male; Melphalan; Mice; Mice, Inbred C3H; Neoplasms, Experimental; Oxygen; Respiration