Cancer letters
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Randomized Controlled Trial Clinical Trial
Inhibition of oxidative DNA damage, 8-OHdG, and carbonyl contents in smokers treated with antioxidants (vitamin E, vitamin C, beta-carotene and red ginseng).
The chemopreventive effects of antioxidants (vitamin E, beta-carotene, vitamin C and red ginseng) on oxidative DNA and protein (globin) damages were comparatively investigated in the peripheral blood of smokers (> or = 20 cigarettes/day). Smokers showed a lower baseline level of plasma micronutrients (vitamin C and beta-carotene) (P < 0.01) and higher baseline level of oxidative DNA or protein damage than non-smokers (N = 5; P < 0.05). ⋯ Levels of urinary and plasma cotinine remained steady in smokers regardless of supplementation with antioxidants. 8-OHdG and carbonyl content decreased in a time-dependent manner (as the total intake dose increased) after supplementation with vitamin E (8-OHdG, 33.8%; carbonyl content, 43.6%) or red ginseng (8-OHdG, 31.7%; carbonyl content, 21.3%). These preliminary data suggest that supplementation with antioxidants might protect smokers from oxidative damages and could reduce cancer risk or other diseases caused by free radicals associated with smoking.
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Comparative Study
Comparison of the therapeutic effects of two vanadium complexes administered at low dose on benzo[a]pyrene-induced malignant tumors in rats.
The antitumor effects of low dose administration of the vanadium(III) complexes with L-cysteine (complex 1) and N-(2-mercaptopropionyl)-glycine (complex 2) were compared on benzo[a]pyrene (BaP)-induced tumors in Wistar rats. Male Wistar rats, injected with 10.0 mg of BaP, were divided into one control (C-G) and two treatment (TR-G) groups of 17 animals each. Animals of the first treatment group were administered complex 2 (TR-2 group) and those of the second group were administered complex 1 (TR-1 group) at doses of 100 microg of vanadium per os daily, starting from the day a palpable tumor was developed till their death. ⋯ Administration of complex 1 to the animals resulted in a significant prolongation of the mean survival time, a complete remission of 17.6% of the tumors developed, a significant reduction of the carcinogenic potency (CP) of BaP and of the tumor growth rate (TGR) in TR-1 group animals, compared to the control and the TR-2 group. In marked contrast, complex 2 failed at the doses administered to exert any significant modulation of the above mentioned parameters. Results indicate that at low (100 micro/day) concentrations of vanadium, complex 1 exerts a significant anticarcinogenic effect on experimentally-induced leiomyosarcomas in rats, whereas complex 2 has no effect when administered at the same low concentrations of vanadium.
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Randomized Controlled Trial Clinical Trial
Retinoids in prevention of skin cancer.
Two chemoprevention randomized clinical trials were begun in 1984 to evaluate retinoids in the prevention of skin cancers. Moderate risk subjects with a history of at least 10 actinic keratoses and at most two prior skin cancers were enrolled in the SKICAP-AK trial and randomized to 25,000 IU retinol or placebo daily for 5 years. ⋯ The effect of retinoids had no significant benefit on squamous or basal cell skin cancers in the high risk subjects on the SKICAP-S/B trial, although intervention duration was less than planned. Daily retinol was effective in preventing squamous cell cancers in moderate risk subjects.
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Cryptophycin 1 is a new cytotoxic antimicrotubule agent with excellent antitumor activity. The methods of Sackett (Biochemistry, 34, 7010-7019, 1995), utilizing the selective and specific proteolysis of alpha- and beta-tubulin by trypsin and chymotrypsin, was used to identify the cryptophycin 1 binding site on tubulin. ⋯ The effects of cryptophycin 1 on the tryptic digests are identical to the effects seen with vinblastine and differ saliently from the effects of maytansine and rhizoxin, other agents known to bind to the vinca site. The data suggest that the binding site of cryptophycin 1 may overlap the vinca binding site on tubulin.