didimethylsulfoxide-dichloroplatinum(ii) and Fibrosarcoma

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

We are searching for relatively nontoxic compounds that can positively modulate the efficacy of antitumor alkylating agents. Lonidamine inhibits cellular energy metabolism and could potentially increase damage by alkylating agents if cellular defenses are energy requiring. Exposure of cells to lonidamine (500 microM) for 2 h under hypoxic conditions followed by 1-h exposures to lonidamine plus alkylating agents under normally oxygenated conditions in vitro significantly increased the cell kill achieved by cis-diamminedichloroplatinum(II) (CDDP) approximately 5-fold and by D-tetraplatin approximately 10-fold at 90% inhibitory concentration in MCF-7/CDDP (CDDP-resistant) cells. Carboplatin cytotoxicity, however, was little changed. In the MCF-7 parent cell line, treatment with lonidamine increased CDDP cytotoxicity by approximately 10-fold, D-tetraplatin by approximately 10-fold, and carboplatin by approximately 8-fold at the 90% inhibitory concentration. For L-phenylalanine mustard (melphalan), N,N',N"-triethylenethiophosphoramide (thiotepa), and N,N'-bis(2-chloroethyl)-N-nitrosourea, little resistance was evident in the MCF-7/CDDP lines compared with the parent line. Treatment with lonidamine increased the cytotoxicity of each drug by 1.5- to 3-fold in both cell lines. When exposure to lonidamine was extended to 24 h before and 12 h after drug exposure in MCF-7 normally oxygenated cultures, CDDP (250 microM) cytotoxicity was increased by approximately 100-fold, but melphalan cytotoxicity was increased only 2- to 3-fold over the concentration range tested. In the FSaIIC murine fibrosarcoma tumor system, five i.p. injections of 50 mg/kg of lonidamine over 36 h increased the tumor cell kill by CDDP and carboplatin approximately 2- to 3-fold over the dose range tested when the platinum complexes were given i.p. immediately after the third lonidamine injection. When cyclophosphamide and thiotepa were given in the same schedule, 10-fold increases in tumor cell killing were evident on tumor excision assay over the dosage ranges. The increase in bone marrow toxicity caused by lonidamine in addition to the alkylating agents was less than for tumor cells. Finally, in the EMT6 murine mammary carcinoma, use of lonidamine at 500 mg/kg twice daily along with CDDP, carboplatin, thiotepa, and cyclophosphamide significantly increased tumor growth delays by approximately 1.6- to 3.0-fold. The results suggest that lonidamine can positively modulate antitumor alkylating agen

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Carboplatin; Carmustine; Drug Resistance; Drug Screening Assays, Antitumor; Drug Synergism; Fibrosarcoma; Humans; Indazoles; Mammary Neoplasms, Animal; Mice; Organoplatinum Compounds; Tumor Cells, Cultured; Tumor Stem Cell Assay

In order to investigate the effect of environmentally determined conditions on the cytotoxicity of anticancer treatments, Hoechst 33342 dye selected tumor subpopulations were separated after in vivo treatment and plated for single cell colony survival. The 10% brightest cells were assayed as putative normally oxygenated cells and the 20% dimmest as putative hypoxic cells. At single therapeutic doses, cyclophosphamide treatment resulted in the largest differential killing between bright and dim cells (6.3-fold bright greater than dim); 1,3-bis(2-chloroethyl)-1-nitrosourea was 3.2-fold more cytotoxic toward bright cells and carboplatin was 2.4-fold more toxic toward bright cells. Both radiation (10 Gy) and melphalan were 2.2-fold more toxic to bright cells, while cis-diamminedichloroplatinum(II) was 1.8-fold, thiotepa was 1.2-fold and procarbazine was 1.3-fold more toxic to bright cells. Actinomycin D was 3.4-fold more toxic to bright cells. Adriamycin was 2.2-fold, vincristine was 2.1-fold, and etoposide was 1.6-fold more toxic to bright cells. Bleomycin and 5-fluorouracil were also tested and were 1.5- and 2.3-fold more toxic to bright cells, respectively. Only four treatments were more toxic to dim cells: mitomycin C (3.5-fold), misonidazole (1.5-fold), etanidazole (3.5-fold), and 43 degrees C, 30 min local hyperthermia (2.6-fold). In an attempt to shift the pattern of dim cell sparing, Fluosol-DA plus carbogen (95% O2/5% CO2) breathing was added to treatment with radiation (10 Gy), melphalan, cis-diamminedichloroplatinum(II), and etoposide. Although each of these treatments became significantly more toxic with the addition of Fluosol-DA/carbogen, only with melphalan did the combination overcome the sparing of dim cells. These results indicate that cells located distally from the tumor vasculature are significantly less affected by most anticancer drugs and suggest that successful therapeutic strategies against solid tumors will involve greater use of the few treatments which are more toxic toward this tumor subpopulation.

Topics: Animals; Antineoplastic Agents; Cell Hypoxia; Cell Survival; Cyclophosphamide; Drug Combinations; Etoposide; Fibrosarcoma; Fluorocarbons; Hydroxyethyl Starch Derivatives; Male; Melphalan; Mice; Mice, Inbred C3H; Organoplatinum Compounds

Our previous in vitro studies demonstrated marked synergy with alkylating agents when novobiocin was present during and after alkylating agent exposure. To determine whether this effect is observed in vivo, novobiocin was administered daily for 3 days prior to alkylating agent treatment, during alkylating agent treatment, and for 2 days after completion of alkylating agent treatment. When combined with cis-diamminedichloroplatinum(II), 1,3-bis(2-chloroethyl)-1-nitrosourea, or cyclophosphamide, there was significant enhancement of the growth delay of the FSaIIC fibrosarcoma implanted s.c. in C3H mice when compared with alkylating agents alone. In a second assay using ex vivo studies of tumor cells exposed in vivo, single doses of 100 mg/kg of novobiocin followed by cis-diamminedichloroplatinum(II) resulted in a 3- to 4-fold increase in tumor cell killing by cis-diamminedichloroplatinum(II). At a dose of 100 mg/kg of 1,3-bis(2-chloroethyl)-1-nitrosourea there was about a 7-fold increase in tumor cell kill upon addition of novobiocin. Cyclophosphamide showed a dose response effect with novobiocin, reaching 13-fold at a dose of 300 mg/kg of cyclophosphamide. In all cases bone marrow elements were affected less than were neoplastic cells, suggesting that the combination of novobiocin and alkylating agents may be a clinically useful strategy.

Topics: Alkylating Agents; Animals; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow; Carmustine; Cell Survival; Cyclophosphamide; Fibrosarcoma; Male; Mice; Mice, Inbred C3H; Neoplasm Transplantation; Novobiocin; Organoplatinum Compounds

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