Activated bleomycin

Hecht SM, Long EC, van Atta RB, De Vroom E, Carter BJ (1990) On the mechanism of bleomycin activation and polynucleotide strand scission. In Bleasdale C, Golding BT (eds) Mol. Mech. Bioorg. Processes, Conference Proceedings. Royal. Soc. Chem., London, pp 100-114 Held AM, Halko DJ, Hurst JK (1978) Mechanisms of chlorine oxidation of hydrogen peroxide. J Am Chem Soc 100 5732-5740... 

Chemotherapeutic agents are grouped by cytotoxic mechanism. The alkylating agents, such as cyclophosphamide [50-18-0] and melphalan [148-82-3] interfere with normal cellular activity by alkylation deoxyribonucleic acid (DNA). Antimetabohtes, interfering with complex metaboHc pathways in the cell, include methotrexate [59-05-2] 5-fluorouracil [51-21-8] and cytosine arabinoside hydrochloride [69-74-9]. Antibiotics such as bleomycin [11056-06-7] and doxombicin [23214-92-8] h.a.ve been used, as have the plant alkaloids vincristine [57-22-7] and vinblastine [865-21-4]. 

The phleomycin, bleomycin and related families are widespectrum antibiotics containing the pyrimidine (987) in addition, they have antineoplastic activity and bleomycin is already in clinical use for certain tumours. They were isolated about 1956 from Streptomyces verticillus, and in addition to the pyrimidine portion the molecules contain an amide part (R ) and a complicated part (R ) consisting of polypeptide, an imidazole, two sugars, a bithiazole and a polybasic side chain which can vary widely phleomycin and bleomycin differ by only one double bond in the bithiazole section (78MI21303). The activity of such antibiotics is increased by the addition of simple heterocycles (including inter alia pyrimidines and fused pyrimidines) and other amplifiers (82MI21300). 

Oligosaccharides also occur widely as components (via glycosidic bonds) of antibiotics derived from various sources. Figure 7.20 shows the structures of a few representative carbohydrate-containing antibiotics. Some of these antibiotics also show antitumor activity. One of the most important of this type is bleomycin A2, which is used clinically against certain tumors. 

In 400 ml of dimethylformamide was dissolved 15.0 g of bleomycinic acid (copper-containing form). To the solution kept at 0°C by cooling were added 1.1 ml of N-methylmorpholine and 10.3 g of 6-chloro-1 -p-chlorobenzenesulfonyloxybenzotriazole (CCBT) as an activating compound. The mixture was stirred for 5 minutes at 0°C, then admixed with 5.3 g of N-[(S)-1 -phenylethyl] -1 3-diaminopropane and further stirred for 1 hour. 

In general, the mechanisms of action are not cell cycle specific, although some members of the class show greatest activity at certain phases of the cell cycle, such as S-phase (anthracyclins, mitoxantrone), Gl- and early S-phases (mitomycin C) and G2- and M-phases (bleomycins). 

To mimic the square-pyramidal coordination of iron bleomycin, a series of iron (Il)complexes with pyridine-containing macrocycles 4 was synthesized and used for the epoxidation of alkenes with H2O2 (Scheme 4) [35]. These macrocycles bear an aminopropyl pendant arm and in presence of poorly coordinating acids like triflic acid a reversible dissociation of the arm is possible and the catalytic active species is formed. These complexes perform well in alkene epoxidations (66-89% yield with 90-98% selectivity in 5 min at room temperature). Furthermore, recyclable terpyridines 5 lead to highly active Fe -complexes, which show good to excellent results (up to 96% yield) for the epoxidation with oxone at room temperature (Scheme 4) [36]. 

Gutteridge, J.M.C. (1987). Bleomycin-detectable iron in knee-joint synovial fluid from arthritic patients and its relationship to the extracellular activities of caeruloplasmin, transferrin and lactoferrin. Biochem. J. 245, 415-421. 

Metal-mediated antibiotics like bleomycin, which requires iron or other metals for activity... 

Kumar A, Brown DT, Leno GH (2004) DNA intercalators differentially affect chromatin structure and DNA repUcation in Xenopus egg extract. Anticancer Drugs 15(6) 633—639 Kuo MT (1981) Preferential damage of active chromatin by bleomycin. Cancer Res 41(6) 2439—2443 Kuo MT, Sarny TS (1978) Effects of neocarzinostatin on mammalian nuclei release of nucleosomes. Biochim Biophys Acta 518(1) 186—190... 

Bleomycin is a complex of no less than 16 glycopeptide antibiotics made from the family Streptomyces verticilus, which have different R groups [88-94]. Bleomycines exhibit antitumor, antiviral, and antibacterial activity. When bound to DNA, they disturb the spiraling of both single and double strands of DNA. To a lesser degree, they inhibit RNA and protein synthesis. It is administered both intravenously and intramuscularly. 

Short term treatment with TPA sensitized human 2008 ovarian carcinoma cells to cis-platin. This sensitization disappeared completely by seven hours after treatment, indicating that not inhibition, but activation of PKC sensitizes 2008 cells to the antiproliferative activity of cis-platin (Isonishi et al., 1990). Pretreatment of HeLa cells with TPA or PdBu caused a 9-fold increase in cellular sensitivity to cis-platin and 2.5-fold to melphalan, but had now effect on the antiproliferative activity of bleomycin, adriamycin, vincristine, or mitomycin C. The sensitization of HeLa cells by TPA was associated with a 6-fold stimulation of PKC activation and a concentration- and time-dependent increase in cellular platinum content. (Basu et al. 1990). PKC activity was found to be decreased significantly in cis-platin-resistant human small cell lung H69/CP cancer cells compared to the drug-sensitive variant. A similar reduction in PKC activity was noted in ovarian carcinoma 2008 cells that were resistant to cis-platin. A modest decrease in PKC activity was also observed in etoposide-resistant H69 cells but not in taxol-resistant H69 cells or bleomycin-resistant human head and neck carcinoma A-253 cells (Basu et al., 1996), indicating that reduced PKC activity leads to decreased sensitivity in this system. 

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