Frequencies of micronucleated cells (MNCs) were analyzed in the exfoliated buccal mucosa of normal healthy individuals from different parts of India who were regularly using either areca nut alone, mava, tamol, tobacco with lime, dry snuff or masheri. The analyses were also carried out among oral submucous fibrosis patients who had the habit of chewing either mava or areca nut. Compared with 'no habit' healthy individuals, all the groups, irrespective of their type of habit, had significantly higher frequencies of MNCs.

Turmeric (Curcuma longa Linn.) has been shown to inhibit chemical carcinogenesis. In this study, we compared the chemopreventive efficacy of an aqueous turmeric extract (AqTE) and its constituents, curcumin-free aqueous turmeric extract (CFAqTE) and curcumin, using the Salmonella typhimurium mutagenicity assay and the bone marrow micronucleus test in female Swiss mice. AqTE exhibited antimutagenic activity against direct-acting mutagens, 4-nitro-O-phenylenediamine and 1-methyl-3-nitro-1-nitrosoguanidine, in strains TA 98 and TA 100 respectively. Both AqTE and CFAqTE inhibited the mutagenicity of benzo [alpha]pyrene in the two strains in the presence of Aroclor-1254-induced rat liver homogenate. The inhibition in both studies was dose-dependent. Administration of AqTE, CFAqTE and curcumin at a dose of 3 mg/animal 18 h prior to i.p. benzo [alpha]pyrene injection (250 mg/kg) significantly inhibited bone marrow micronuclei formation in female Swiss mice by 43%, 76%, and 65% respectively. Furthermore, the incidence and multiplicity of forestomach tumours induced by benzo [alpha]pyrene (1 mg/animal, twice weekly, p.o. for 4 weeks) in female Swiss mice were significantly inhibited by AqTE, CFAqTE and curcumin given 2 weeks before, during and after the carcinogen treatment. These data indicate that the protection against genomic damage by turmeric extract and its components tested could be necessary for some aspects of its cancer chemoprevention.

Four carotenoids, canthaxanthin, beta-carotene, 8H-apo-beta-carotenal, and 8'-apo-beta-carotene methylester were tested for their ability to suppress the mutagenicity of 1-methyl-3-nitro-1-nitrosoguanidine and benzo[a]pyrene (BP) in Salmonella typhimurium tester strain TA 100. The anticarcinogenic efficacy of the four carotenoids was further assessed in the BP-induced forestomach tumor model in female Swiss mice. The effect of dietary palm oil was also examined in BP-induced neoplasia in the female Haffkine Swiss mouse strain. Canthaxanthin, beta-carotene, 8'-apo-beta-carotenal, and 8'-apo-beta-carotene methylester showed a dose-dependent decrease in the mutagenicity compared with 1-methyl-3-nitro-1-nitrosoguanidine and BP in strain TA 100. In the BP-induced forestomach tumor model, all four carotenoids showed a similar significant anticarcinogenic effect. Dietary administration of palm oil showed a dose-dependent antitumor activity in the animals. Our results show that the intrinsic antimutagenic and anticarcinogenic properties of the carotenoids are not significantly influenced by their conversion to vitamin A.

CD cell line has been established from a poorly differentiated squamous cell carcinoma of tongue. This is a first ever cell line established from an Indian gutka chewer. Cell line was characterized for morphology, ultrastructure, doubling time, expression of epithelial markers, DNA content, karyotyping, STR markers, p53 mutations, HPV status, and tumorigenicity in SCID mice with all-trans-retinoic acid and cisplatin. The epithelial phenotype of the cell line was confirmed with surface markers and ultrastructure. The cell line is hyperploid with chromosomal alterations like gain of chromosomes 8q and 11q. CD cell line shows a unique pattern on STR genotyping and carries a missense mutation R273C inTP53. It does not show genomic integration of HPV. The cells are nontumorigenic to SCID mice and show growth inhibition upon treatment with cisplatin, and all-trans-retinoic acid. This cell line may be useful as an in vitro tool to understand the molecular changes associated with oral cancers.

No abstract

The activities of several activating enzymes and that of glutathione S-transferase as well as levels of glutathione were measured in the upper alimentary tract, lung, and liver of Swiss mice, Sprague-Dawley rats, and Syrian golden hamsters treated with 10% masheri (pyrolyzed tobacco) in diet for 20 months. Significant increase in activities of phase I activating enzymes and a remarkable decrease in the phase II detoxification system in most extrahepatic tissues of the treated animals of all three species was observed. These observations suggest that the prolonged exposure to environmental xenobiotics/carcinogens affects the drug-metabolizing enzymes of the gastrointestinal tract, which may be an important factor in determining the susceptibility of different organs to carcinogen exposure.