Prevention of chemotherapy toxicity by agents that neutralize or degrade cell-free chromatin.

BACKGROUND: Toxicity associated with chemotherapy is a major therapeutic challenge and is caused by chemotherapy-induced DNA damage and inflammation. We have recently reported that cell-free chromatin (cfCh) fragments released from dying cells can readily enter into healthy cells of the body to integrate into their genomes and induce DNA double-strand breaks, apoptosis and inflammation in them. We hypothesized that much of the toxicity of chemotherapy might be due to release of large quantities of cfCh from dying cells that could trigger an exaggerated DNA damage, apoptotic and inflammatory response in healthy cells over and above that caused by the drugs themselves. METHODS: We tested this hypothesis by administering cfCh neutralizing/degrading agents namely, anti-histone antibody complexed nanoparticles, DNase I and a novel DNA degrading agent-Resveratrol-Cu concurrently with five different chemotherapeutic agents to examine if chemotherapy-induced toxicity could be minimized. RESULTS: We observed (i) significant reduction in chemotherapy-induced surge of cfCh in blood; (ii) significant reduction in chemotherapy-induced surge of inflammatory cytokines CRP, IL-6, IFNγ and TNFα in blood; (iii) abolition of chemotherapy-induced tissue DNA damage (γH2AX), apoptosis (active caspase-3) and inflammation (NFκB and IL-6) in multiple organs and peripheral blood mononuclear cells; (iv) prevention of prolonged neutropenia following a single injection of adriamycin and (v) significant reduction in death following a lethal dose of adriamycin. CONCLUSION: Our results suggest that toxicity of chemotherapy is caused to a large extent by cfCh released from dying cells and can be prevented by concurrent treatment with cfCh neutralizing/degrading agents.

Two oligosaccharides from Marsdenia roylei.

Phytochemical analysis of dried twigs of Marsdenia roylei (family Asclepiadaceae) has resulted in the isolation of a trisaccharide, maryal, and a diglycoside, rolinose. Their structures were determined as O-beta-D-oleandropyranosyl-(1-->4)-O-beta-D-digitoxopyranosyl++ +-(1-->4)-D- cymaral and ethyl O-beta-D-oleandropyranosyl-(1-->4)-O-3-O-methyl-6-deoxy-beta-D- allopyranoside, respectively, by chemical degradation and spectroscopic methods.

Trisaccharides from Marsdenia roylei.

The structures of two novel trisaccharides viz. royleose and deniose isolated from Marsdenia roylei were elucidated with the help of modern physico-chemical techniques and chemical transformations. They were defined as O-beta-D-oleandropyranosyl-(1-->4)-O-beta- D-cymaropyranosyl-(1-->4)-beta-D-oleandropyranose and O-beta-D-oleandropyranosyl-(1-->4)-O-beta-D-digitoxopyranosyl++ +-(1-->4)- beta-D-oleandropyranose respectively. This is the first report on the isolation of trisaccharides of rare deoxy sugars in free state from nature.

Structure of the glycopeptidolipid antigen of serovar 20 of the Mycobacterium avium serocomplex, synthesis of allyl glycosides of the outer di- and tri-saccharide units of the antigens of serovars 14 and 20, and serology of the derived neoglycoproteins.

The tetrasaccharide hapten released from the glycopeptidolipid (GPL) antigen of Mycobacterium avium serovar 20 has been characterized as O-(2-O-methyl-alpha-D-rhamnopyranosyl)-(1----3)-O-(2-O-methyl-alpha-L- fucopyranosyl)-(1----3)-alpha-L-rhamnopyranosyl-(1----2)-6-deoxy-L-talos e. Syntheses are reported of allyl glycosides of the outer disaccharide unit of this hapten, O-(2-O-methyl-alpha-D-rhamnopyranosyl)-(1----3)-2-O-methyl-alpha-L-fu copyranose , and also of the outer di- and tri-saccharide units of the GPL antigen of M. avium serovar 14, O-(N-formyl-alpha-L-kansosaminyl)-(1----3)-2-O-methyl-alpha-D-rham nopyranose and O-(N-formyl-alpha-L-kansosaminyl)-(1----3)-O-(2-O-methyl-alpha-D- rhamnopyranosyl)-(1----3)-2-O-methyl-alpha-L-fucopyranose. The key steps in the latter synthesis involve the preparation of allyl 4-azido-4,6-dideoxy-3-C-methyl-2-O-methyl-alpha-L-mannopyranoside as a precursor for the N-formylkansosamine unit, followed sequentially by conversion into and use of a trichloroacetimidate as glycosyl donor for di- and tri-saccharide formation, O-deacylation, reduction, and N-formylation. The allyl glycosides, representative of the haptens from both serovars, have been converted into neoglycoproteins (NGPs) and their serological activities have been compared in the light of the structural relationship between them.

Synthesis of allyl glycosides for conversion into neoglycoproteins bearing epitopes of mycobacterial glycolipid antigens.

Neoglycoproteins bearing key glycosyl substituents of several glycopeptidolipid antigens of pathogenic Mycobacterium species have been synthesized. Allyl glycosides of the terminal 6-deoxyhexose-containing units of the antigens were prepared, with appropriate ether and ester substituents in place. Ozonolysis of the allyl glycosides was then followed by reductive coupling with epsilon-amino groups of lysine residues in bovine serum albumin, using sodium cyanoborohydride at pH 7.8. The resulting neoglycoproteins emulated the antigenicity of the native molecule in several serological tests.

Effects of subtoxic levels of lead and cadmium on urogenital organs of male rats.

Higher incidence of prostate cancer among lead and cadmium smelter workers has been reported. Forty male rats were divided into four groups. Group I served as control; Group II was injected intraperitoneally, close to the site of the prostate, with 0.05 mg lead acetate; Group III was injected with 0.05 mg cadmium chloride; and Group IV was injected with a combination of 0.025 mg lead and 0.025 mg cadmium chloride. After daily injection for one month, lead and cadmium had a synergistic effect on testicular damage and prostatic cytology; although no tumor formation was observed in the prostate, there was replacement of columnar epithelium by squamous epithelium, suggestive of progressive, precancerous changes. There was an increase in incidence of stone formation in the kidney and urinary bladder.

A novel pregnane derivative from Sarcostemma brevistigma.

A new pregnane derivative designated as bregenin [1] has been isolated from the dried twigs of Sarcostemma brevistigma. Chemical and spectroscopic evidence is consistent with the structure 3 beta, 14 beta, 16 alpha, 17 beta tetrahydroxypregn-5-en-20-one for bregenin.

Synthesis of disaccharides related to the mycobacterial arabinogalactan.

Several novel glycofuranoses disaccharides related to mycobacterial cell wall polysaccharides were synthesized regio- and stereoselectively using 2,3,5-tri-O-benzoyl-alpha-D-arabinofuranosyl trichloroacetimidate as a glycosyl donor.