naphthoquinones and Lymphoma

1-(2-Methoxyethyl)-2-methyl-4,9-dioxo-3-(pyrazin-2-ylmethyl)-4,9-dihydro-1H-naphtho[2,3-d]imidazolium bromide (YM155 monobromide) is a novel small-molecule survivin suppressant that induces the down-regulation of survivin and exhibits potent antitumor activity in nude mice bearing the human hormone refractory prostate carcinoma cell line PC-3. In this study, radioluminographic determination of the in vivo distribution of radioactivity after administration of [(14)C]YM155 to PC-3-xenografted nude mice revealed a relatively high level of radioactivity in the PC-3 xenograft. Therefore, the uptake of [(14)C]YM155 was further characterized in vitro using PC-3, lung cancer (Calu-6 and NCI-H358), malignant melanoma (A375 and SK-MEL-5), and non-Hodgkin's lymphoma (RL and Ramos) cell lines. The uptake of [(14)C]YM155 in these cell lines was dependent on incubation time, temperature, and drug concentration. The Michaelis-Menten constant values were similar among the seven cell lines (0.189-0.367 microM). The effects of various compounds on the uptake of [(14)C]YM155 were tested in PC-3, Calu-6, A375, RL, and Ramos cell lines. Of the compounds tested, the cationic transporter substrates/inhibitors (tetraethylammonium, 1-methyl-4-phenylpyridium, cimetidine, prazosin, corticosterone, verapamil, amantadine, procainamide, and N-methylnicotinamide) inhibited the uptake of [(14)C]YM155 to a similar extent among the five cell lines. The half-maximal inhibitory concentration values (IC(50)) of several compounds for the uptake of [(14)C]YM155 into PC-3 differed from those reported in the literature for human organic cation transporter 1 (OCT1/SLC22A1), OCT2 (SLC22A2), and OCT3 (SLC22A3). To summarize, YM155 was taken up into cancer cells in a carrier-mediated manner and with a similar affinity among all the cancer cell lines tested. An influx transporter(s) may contribute to this process.

Topics: Animals; Carbon Radioisotopes; Cell Line, Tumor; Drug Carriers; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Lymphoma; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Microtubule-Associated Proteins; Naphthoquinones; Neoplasms; Survivin

Plumbagin, a naphtoquinone present in the roots of Plumbago zeylanica, has been reported to have many beneficial effects such as antibacterial, antifungal, anticancer, antimutagenic and antioxidant effects, but this compound has also been reported to have many side effects. Given the wide use of P. zeylanica in traditional medicine and the various potential therapeutic uses of plumbagin, the present study was carried out to further elucidate the potential genotoxicity and antigenotoxicity of plumbagin in mouse lymphoma L5178Y cells, using the comet assay. Without affecting the cell viability, plumbagin itself was found to induce significant DNA damage at concentrations as low as 0.25 ng/ml. When the cells were exposed to non-DNA damaging concentrations of plumbagin, together with NQNO (known to interact with DNA in many different ways) or catechol (known to induce oxidative DNA damage), plumbagin was found to significantly reduce the catechol-induced DNA damage, but to be without protective effect against the NQNO-induced damage. The fact that non-DNA damaging concentrations of plumbagin diminished the DNA damage induced by catechol, provides further support for the idea that plumbagin may act as an antioxidative agent at low concentrations.

Topics: Animals; Antimutagenic Agents; Antineoplastic Agents, Phytogenic; Catechols; Cell Line, Tumor; Cell Survival; Comet Assay; DNA Damage; Dose-Response Relationship, Drug; Drug Combinations; Drug Interactions; Drug Screening Assays, Antitumor; Hydroxyquinolines; Lymphoma; Mice; Naphthoquinones

The peptidyl-prolyl isomerase Pin1 is frequently up-regulated in human cancers in which Rel/nuclear factor-kappaB (NF-kappaB) is constitutively activated, but its role in these cancers remains to be determined, and evidence is still lacking to show that Pin1 contributes to cell transformation by Rel/NF-kappaB. Rel/NF-kappaB transcriptional and oncogenic activities are modulated by several posttranslational modifications and coregulatory proteins, and previous studies showed that cytokine treatment induces binding of Pin1 to the RelA subunit of NF-kappaB, thereby enhancing RelA nuclear localization and stability. Here we show that Pin1 associates with the Rel subunits of NF-kappaB that are implicated in leukemia/lymphomagenesis and modulates their transcriptional and oncogenic activities. Pin1 markedly enhanced transformation of primary lymphocytes by the human c-Rel protein and also increased cell transformation by the potent viral Rel/NF-kappaB oncoprotein v-Rel, in contrast to a Pin1 mutant in the WW domain involved in interaction with NF-kappaB. Pin1 promoted nuclear accumulation of Rel proteins in the absence of activating stimuli. Importantly, inhibition of Pin1 function with the pharmacologic inhibitor juglone or with Pin1-specific shRNA led to cytoplasmic relocalization of endogenous c-Rel in human lymphoma-derived cell lines, markedly interfered with lymphoma cell proliferation, and suppressed endogenous Rel/NF-kappaB-dependent gene expression. Together, these results show that Pin1 is an important regulator of Rel/NF-kappaB transforming activity and suggest that Pin1 may be a potential therapeutic target in Rel/NF-kappaB-dependent leukemia/lymphomas.

Topics: Amino Acid Sequence; Animals; Cell Nucleus; Cell Proliferation; Cell Transformation, Neoplastic; Cells, Cultured; Chickens; Humans; Lymphoma; Molecular Sequence Data; Multigene Family; Naphthoquinones; NF-kappa B; NIMA-Interacting Peptidylprolyl Isomerase; Oncogene Proteins v-rel; Peptidylprolyl Isomerase; Protein Binding; Protein Transport; Sequence Homology, Amino Acid; Up-Regulation

The antitumour activity of Rhinacanthone (3,4-dihydro-3,3-dimethyl-2H-naphtho-[1,2-B] pyran-5,6-dione) has been evaluated against Dalton's ascitic lymphoma (DAL) in Swiss albino mice. A significant enhancement of mean survival time of tumour bearing mice and peritoneal cell count in normal mice was observed with respect to the control group. When these Rhinacanthone treated animals underwent i.p. inoculation with DAL cells, tumour cell growth was found to be inhibited. After 14 d of inoculation, Rhinacanthone was able to reverse the changes in the haemotological parameters, protein and packed cellular volume consequent to tumour inoculation.

Topics: Animals; Antineoplastic Agents, Phytogenic; Ascitic Fluid; Benzopyrans; Lymphoma; Male; Mice; Naphthoquinones; Neoplasm Transplantation; Plant Extracts; Plants, Medicinal; Tumor Cells, Cultured

Topics: Animals; Ascites; Carbohydrate Metabolism; Cell Respiration; Glycolysis; Lymphoma; Metabolism; Mice; Naphthoquinones; Neoplasms, Experimental; Vitamin K

Topics: Animals; Antifibrinolytic Agents; Ascites; Carcinoma; Glycolysis; Lymphoma; Metabolism; Mice; Naphthoquinones; Neoplasms, Experimental; Vitamin K; Vitamin K 1; Vitamins