vitamin-k-semiquinone-radical and Leukemia-P388

The effect of vitamin K3 (2-methyl-1,4-naphthoquinone) on Adriamycin (ADR) induced growth inhibition of drug sensitive and multidrug resistant P388 leukemia cells was evaluated. Exposure to ADR concentrations of 100-5000 ng simultaneously with 1 microM vitamin K3 elicited an enhanced inhibition of tumor cell survival. The effect of treatment with ADR alone, or in combination with vitamin K3 on DNA and RNA biosynthesis in the sensitive and resistant tumor cells, was also assessed. DNA and RNA biosynthesis inhibition was increased in P388/S (the parental cell line) and P388/ADR cells (the ADR resistant cell line which exhibits the multidrug resistant (MDR) phenotype) exposed to ADR after pretreatment for 3 h with vitamin K3. Concurrent administration in vivo of vitamin K3 and ADR illustrated a therapeutically significant increase (P less than 0.05) in the life span of sensitive and resistant tumor cell bearing animals. Vitamin K3 caused a depletion of the intracellular glutathione (GSH) levels in P388/S and P388/ADR leukemia cells but at concentrations greater than those that enhanced ADR cytotoxicity. Pretreatment of the tumor cells with 1 microM vitamin K3 induced a 35-50% (P less than 0.001) elevation in the intracellular ADR accumulation in MDR P388 leukemia cells, while such an effect was absent in P388/S tumor cells. DNA binding studies performed utilizing calf thymus DNA, indicated that vitamin K3 enhanced the intercalation potential of ADR and also altered the equilibrium between the free and bound form of ADR in a cell free system. These factors and their possible effects on the potentiation of ADR cytotoxicity and the therapeutic significance of utilizing vitamin K3 as an adjuvant in the chemotherapy of MDR tumors is discussed.

Topics: Animals; Cell Survival; DNA; DNA, Neoplasm; Doxorubicin; Drug Resistance; In Vitro Techniques; Leukemia P388; Leukemia, Experimental; Mice; RNA, Neoplasm; Spectrum Analysis; Tumor Cells, Cultured; Vitamin K

Cytotoxic effects of vitamin K3 were evaluated utilizing the P388/S, L1210, EAT, S-180 and a multidrug-resistant variant of the P388 leukemia cells (P388/ADR). Antitumorigenic potential of vitamin K3 was assessed by MTT and DNA and RNA biosynthesis inhibition assay. A dose-dependent inhibition of P388/S and P388/ADR cell survival and [3H]thymidine and [3H]uridine incorporation (as a function of DNA and RNA biosynthesis) was observed in tumor cell types exposed to vitamin K3 concentrations ranging from 1 to 100 microM. One hundred mg/kg vitamin K3 caused a 32 and 52% increase in life span of the sensitive and resistant P388 leukemia tumor-bearing mice. Induction of DNA strand breaks at 100 microM vitamin K3 was greater in P388/S than in P388/ADR cells. In vitro treatment with vitamin K3 (100 microM) reduced the intracellular levels of GSH by 40, 47, 6, 15 and 14% in P388/S, P388/ADR, EAT, S-180 and L1210 tumor cells, respectively. In vivo treatment with 100 mg/kg vitamin K3 reduced the GSH content by 18 and 38% and increased the activity of the enzyme GSH-S-transferase and gamma-glutamyl transpeptidase. Effects of free radical scavengers and of compounds that modulate the GSH metabolism on the cytotoxicity of vitamin K3 were also investigated. Results indicate that vitamin K3 interacts with the tumor cell thiol pools while eliciting its antitumor effects and suggest the utility of vitamin K3 in dealing with the growing problem of multidrug resistance.

Topics: Animals; Cell Survival; DNA Damage; DNA, Neoplasm; Doxorubicin; Drug Resistance; Free Radical Scavengers; gamma-Glutamyltransferase; Glutathione; Glutathione Transferase; Kinetics; Leukemia L1210; Leukemia P388; Mice; Mice, Inbred DBA; Neoplasm Transplantation; Neoplasms, Experimental; RNA, Neoplasm; Sulfhydryl Compounds; Tumor Cells, Cultured; Vitamin K

Vitamin K3 was employed as a resistance-modifying agent to investigate its activity in enhancing mitoxantrone (MITO)-induced cytotoxicity in parental (P388/S) and multidrug resistant (P388/ADR) P388 leukemia cells. Vitamin K3 potentiated the antitumor effects of MITO in P388/S and P388/ADR tumor cells as monitored by inhibition of tumor cell survival (MTT assay). MITO and vitamin K3 in combination effected an enhanced inhibition of [3H]thymidine (DNA synthesis) and [3H]uridine (RNA synthesis) and also increased the life span of the sensitive and resistant tumor-bearing animals. The effect of vitamin K3 on the induction of DNA strand breaks by MITO was also examined. Increased fragmentation of DNA was illustrated in the sensitive and resistant P388 leukemia cells exposed to the combination. Observations indicate the restoration of sensitivity in P388/ADR cells to MITO by vitamin K3 that may be due to its ability to increase the MITO-induced DNA strand breaks.

Topics: Animals; Cell Division; DNA Damage; DNA, Neoplasm; DNA, Single-Stranded; Doxorubicin; Drug Resistance; Drug Synergism; Female; Leukemia P388; Male; Mice; Mice, Inbred DBA; Mitoxantrone; RNA, Neoplasm; Vitamin K

The toxicity of daily subcutaneously applied 500 mg/kg N-methylformamide (NMF) during a period of 8 days in female CD-mice was ameliorated when 100 mg/kg sodium ascorbate, 60 mg/kg menadione bisulfite or 80 mg/kg pyridoxal hydrochloride were applied simultaneously. The comparison of the daily s.c. application of 360 mg/kg NMF with the intermittent s.c. injection of 720 mg/kg NMF with an interval of 48 h in P 388 leukemia showed that the daily application of NMF induced an increase of life span of 82% whereas the intermittent schedule effected a 142% increase of life span. The simultaneous combination of 360 mg/kg NMF with 60 mg/kg sodium ascorbate applied daily caused a 133% increase of life span and the simultaneous combination of 360 mg/kg NMF with 30 mg/kg menadione sodium bisulfite lead to a 126% increase of life span. The combined daily s.c. application of 360 mg/kg NMF with 30 mg/kg pyridoxal hydrochloride induced only a minimal difference compared to the daily application of 360 mg/kg NMF alone. The combination of 720 mg/kg NMF with 120 mg/kg sodium ascorbate applied in intervals of 48 h showed a 164% increase of life span. In advanced M 5076 sarcoma the daily s.c. application of 360 mg/kg NMF effected a 82% increase of life span and the combination of 360 mg/kg NMF with 60 mg/kg sodium ascorbate effected a 135% increase of life span.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Drug Synergism; Female; Formamides; Leukemia P388; Life Expectancy; Mice; Pyridoxal; Sarcoma, Experimental; Vitamin K; Vitamin K 3