novobiocin and Lung-Neoplasms

Novobiocin, a commercially available oral antibiotic, inhibits DNA topoisomerase II in a manner shown in cell culture to enhance the cytotoxicity of alkylating agents and cisplatin. Thirty-six patients were entered on a Phase II trial using high-dose cisplatin (100 mg/m2 on days 1 and 8 for four cycles) after steady-state dosing with novobiocin (1000 mg or four 250-mg capsules every 12 hours for six doses, four of which were administered before each dose of cisplatin). One patient remains on study and cannot be evaluated for response. No complete responses were seen. Three patients (8%) had partial responses and an additional patient had an unconfirmed partial response. The median survival time of all patients was just less than 7 months. These results are comparable with those of other concurrent Southwest Oncology Group (SWOG) Phase II and III trials of high-dose cisplatin in non-small cell lung cancer (NSCLC). Novobiocin plasma levels were obtained for three patients and were approximately 50% of the optimal concentration as reported in cell culture for potentiation of cytotoxicity. It was concluded that an optimum test of novobiocin as a modulator of cytotoxicity may require the availability of an intravenous preparation.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Capsules; Carcinoma, Non-Small-Cell Lung; Cisplatin; Drug Evaluation; Female; Humans; Infusions, Intravenous; Kidney; Lung Neoplasms; Male; Middle Aged; Novobiocin; Remission Induction; Southwestern United States

Heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90) chaperones are indispensable to lung cancer cells for their survival and proliferation. In this study we evaluated and compared anticancer potential of methylene blue (MB) as an Hsp70 inhibitor, novobiocin (NB) a well-known Hsp90 inhibitor and their combination.. In vitro evaluation was done by cell viability assays, fluorescent staining, and flow cytometry analysis using A549 non-small cell lung cancer cells. In vivo anticancer activity was investigated by evaluating oxidative stress, tumor biomarkers, weight, lung microarchitecture, and Hsp70 and Hsp90 inhibitions via immunoblotting in benzo[a]pyrene induced lung carcinogenesis mice model.. Using A549 NSCLC cells, we found MB demonstrated lower cell viability versus NB. Together, MB + NB resulted in further decrease in cell viability. SRB assay revealed significantly superior and similar potency for MB versus NB and MB + NB (1:1) versus MB, respectively. Fluorescent staining and flow cytometry analysis displayed early apoptosis by MB (11.4%); early and late apoptosis by MB + NB (13.8%). In vivo, MB significantly inhibited Hsp70. Furthermore, MB significantly alleviated tumor biomarkers (ADA and LDH) and improved lung histopathological features more than NB. Additionally, MB significantly improved SOD, not more than MB + NB or NB and improved LPO.. MB demonstrated potent anticancer activity in vitro and in vivo via inhibition of Hsp70 in benzo[a]pyrene induced lung carcinogenesis in mice.

Topics: A549 Cells; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzo(a)pyrene; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Cell Proliferation; Cell Survival; Flow Cytometry; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Humans; Lung Neoplasms; Male; Methylene Blue; Mice; Novobiocin; Oxidative Stress

Breast cancer resistance protein (BCRP/ABCG2) of an ATP-binding cassette half-transporter confers resistance against mitoxantrone and camptothecin derivatives of topotecan and irinotecan. Novobiocin, a coumermycin antibiotic, is known to enhance anticancer drug sensitivity of cancer cells in vitro and in vivo, the mechanism of which remains undetermined. Here we focused on drug efflux pump and examined whether novobiocin reversed drug resistance in multidrug-resistant cells highly expressing BCRP. To explore the reversal mechanisms, intracellular drug accumulation was measured by flow cytometry, and a topotecan transport study using plasma membrane vesicles was performed. We used PC-6/SN2-5H2 small cell lung cancer and MCF-7/MX breast cancer cells selected with SN-38 of the active irinotecan metabolite and mitoxantrone, respectively, and the BCRP cDNA transfectant MCF-7/clone 8 cells. These cells expressed high levels of BCRP mRNA but not other known transporters. Compared to the parental PC-6 cells, PC-6/SN2-5H2 cells were 141-, 173- and 57.2-fold resistant to topotecan, SN-38 and mitoxantrone, respectively. Novobiocin at 60 microM decreased the degree of the above resistance by approximately 26-fold in PC-6/SN2-5H2 cells, and similarly reversed resistance in MCF-7/MX, MCF-7/clone 8 and un-selected NCI-H460 cells highly expressing BCRP. Furthermore, novobiocin increased the intracellular topotecan accumulation in these cells and inhibited the topotecan transport into the membrane vesicles of PC-6/SN2-5H2 cells. No effects of novobiocin in these assay were observed in the parental PC-6 and MCF-7 cells. The kinetic parameters in the transport study indicated that novobiocin was a inhibitor for BCRP, resulting in competitive inhibition of BCRP-mediated topotecan transport. These findings suggest that novobiocin effectively overcomes BCRP-mediated drug resistance at acceptable concentrations.

Topics: Aminocoumarins; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Breast Neoplasms; Camptothecin; Coumarins; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Irinotecan; Lung Neoplasms; Mitoxantrone; Neoplasm Proteins; Novobiocin; Topoisomerase I Inhibitors; Topotecan; Tumor Cells, Cultured

Previous reports from this laboratory have demonstrated that novobiocin produces supraadditive cytotoxicity and increases the formation of drug-stabilized topoisomerase II-DNA covalent complexes in WEHI-3B myelomonocytic leukemia and A549 lung carcinoma cells when combined with etoposide (VP-16). Inhibition of the efflux of VP-16 by novobiocin is responsible for the increase in VP-16 accumulation, which in turn leads to increased formation of VP-16-stabilized topoisomerase II-DNA covalent complexes and increased cytotoxicity. We now report that novobiocin synergistically enhanced the sensitivity of the multidrug resistant variants, WEHI-3B/NOVO and A549(VP)28, to VP-16, causing almost complete reversal of the resistance to the epipodophyllotoxin. These two tumor cell variants are resistant to several topoisomerase II-targeted drugs, particularly VP-16, but not to Vinca alkaloids; this finding corresponds to the fact that they do not overexpress the P-glycoprotein. The effects of novobiocin in these resistant sublines are mediated through the intracellular accumulation of VP-16, resulting in an increase in the formation of lethal VP-16-induced topoisomerase II-DNA covalent complexes. In the P-glycoprotein expressing multidrug resistant HCT116(VM)34 colon carcinoma and L1210/VMDRC0.06 leukemia cell lines, the latter being transfected with the human mdr-1 gene, novobiocin did not potentiate the cytotoxic activity of VP-16 nor increase the intracellular accumulation of VP-16 and the formation of covalent complexes, whereas their normal counterparts were sensitive to the potentiating activity of novobiocin when used in combination with VP-16. These results indicate that the action of novobiocin on the intracellular transport of VP-16 is not directed at the level of the P-glycoprotein, but that the action of novobiocin is antagonized by the presence of the P-glycoprotein. Since novobiocin is a clinically available antibiotic, has numerous structural analogues available for comparative studies, and has a relatively low toxicity profile, this drug, as well as structurally related agents, would appear to have significant clinical potential in combination with an epipodophyllotoxin for the treatment of non-P-glycoprotein expressing multidrug resistant tumors.

Topics: Adenocarcinoma; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Carrier Proteins; Colonic Neoplasms; DNA Topoisomerases, Type II; DNA, Neoplasm; Drug Resistance; Etoposide; Flow Cytometry; Humans; Leukemia L1210; Lung Neoplasms; Membrane Glycoproteins; Mice; Novobiocin; Tumor Cells, Cultured

The coumermycin antibiotic novobiocin, which interacts with the nuclear enzyme topoisomerase II, produced supra-additive toxicity to WEHI-3B D+ leukemia cells at clinically achievable concentrations, when combined with teniposide (VM-26) or etoposide (VP-16). Simultaneous exposure of cells to both agents was required for maximum efficacy of the combination. Novobiocin also produced supra-additive toxicity to A549 human lung carcinoma cells when combined with VM-26 or VP-16. At concentrations above the peak plasma levels achievable in patients, novobiocin lost its potentiating activity. Exposure of WEHI-3B D+ cells to novobiocin did not modify the cytotoxicity produced by the topoisomerase II inhibitor m-AMSA, whereas, in contrast, novobiocin antagonized the cytotoxicity of m-AMSA in A549 cells. Although it has been suggested that inhibitors of the syntheses of DNA and RNA interfere with the cytotoxic activity of the epipodophyllotoxins, maximum potentiation of the cytotoxicities of VP-16 and VM-26 occurred at novobiocin concentrations that decreased the rates of synthesis of both DNA and RNA in WEHI-3B D+ cells by about 50%. The number of DNA-topoisomerase-II covalent complexes stabilized by VM-26 in WEHI-3B D+ cells was greatly increased when cells were exposed simultaneously to VM-26 and novobiocin for 1 hr, but not when cells were treated with m-AMSA and novobiocin for the same period of time. Novobiocin did not affect the amount of covalent complexes produced by VM-26 in isolated nuclei, suggesting that the potentiating activity of novobiocin was not due to its direct interaction with the nuclear topoisomerase II enzyme. Our findings suggest that therapeutic levels of novobiocin may be capable of enhancing the clinical activities of VP-16 and VM-26.

Topics: Adenocarcinoma; Amsacrine; Antineoplastic Combined Chemotherapy Protocols; Cell Survival; DNA; DNA Topoisomerases, Type II; Drug Synergism; Etoposide; Humans; Leukemia; Lung Neoplasms; Novobiocin; RNA; Teniposide; Topoisomerase II Inhibitors; Tumor Cells, Cultured

Comparisons have been made of the DNA polymerases of normal human lung and cecum, primary carcinomas of human lung, breast, and cecum, and resting and regeneration rat liver. The picture for the normal human tissues is similar to the one for unstimulated rat liver, that for the human carcinomas resembles regenerating rat liver. The human tissues contain two polymerases with sedimentation coefficients of about 3 and 7 S, the enzymes are restricted to the nucleus, and the specific activities of the 7 S polymerase, but not of the 3 S enzyme, are elevated in the cancers. Just as with the regenerating rat liver polymerases, the 3 S activity of a bronchogenic carcinoma is unaffected by cytosine arabinoside 5'-triphosphate and only little reduced by novobiocin, whereas DNA synthesis by the 7 S enzyme is abolished by both compounds. A variety of other inhibitory agents have similar effects on the 7 S polymerases of the human carcinomas and regenerating rat liver.

Topics: Animals; Breast Neoplasms; Cecal Neoplasms; Cecum; Cell Nucleus; Cytarabine; DNA-Directed DNA Polymerase; DNA, Neoplasm; Humans; Isoenzymes; Liver; Liver Regeneration; Lung; Lung Neoplasms; Neoplasms; Novobiocin; Nucleic Acid Synthesis Inhibitors; Rats