Umberto Saffiotti

α and β-Retinyl acetate reverse metaplasias of vitamin A deficiency in hamster trachea in organ culture

DEFICIENCY of vitamin A causes a well-defined lesion, namely keratinised squamous metaplasia, in tracheobronchial epithelium1. In this lesion, the normal columnar ciliated and mucus cells of the epithelium, which depend on vitamin A for their formation, are totally replaced by squamous cells which produce keratin. The mechanism of action of vitamin A in controlling this normal differentiation of ciliated and mucus cells is still unknown. We report here an in vitro system for studying this process, using organ culture of hamster tracheas in a chemically defined, serum-free medium. Growth of tracheas in this medium without vitamin A causes keratinised squamous lesions. Addition of vitamin A to the organ cultures after development of such lesions causes reversal of the process of keratinisation and replacement of the squamous cells by columnar ciliated and mucus cells.

Second Primary Tumors in Head and Neck Cancer Patients

XAVIER LEÓN, ALFIO FERLITO, CHARLES M. MYER III, UMBERTO SAFFIOTTI, ASHOK R. SHAHA, PATRICK J. BRADLEY, MARGARET S. BRANDWEIN, MATTI ANNIKO, RAVINDHRA G. ELLURU and ALESSANDRA RINALDO From the Department of Otolaryngology, Hospital de Santa Creu i Sant Pau, Barcelona, Spain, Department of Otolaryngology—Head and Neck Surgery, University of Udine, Udine, Italy, Department of Pediatric Otolaryngology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland , USA, Head and Neck Service, Memorial Sloan–Kettering Cancer Center, New York, New York, USA, Department of Otorhinolaryngology —Head and Neck Surgery, Queen’s Medical Centre, Nottingham, UK, Department of Otolaryngology and Pathology, Mount Sinai School of Medicine, New York, New York, USA and Department of Otolaryngology—Head and Neck Surgery, University Hospital, Uppsala, Sweden

Generation of Reactive Oxygen Species by Quartz Particles and Its Implication for Cellular Damage

Abstract Using wet analytical chemistry and electron spin resonance spin trapping, we have shown that aqueous suspensions of freshly fractured quartz particles generated hydrogen peroxide, hydroxyl radical, superoxide radical, and singlet oxygen. Superoxide dismutase partially inhibited the hydroxyl radical yield, whereas catalase suppressed it. Hydrogen peroxide enhanced the hydroxyl radical generation, while deferoxamine decreased it. Oxygen consumption measurements showed that freshly fractured quartz particles consumed molecular oxygen. Electrophoretic assays showed that freshly fractured quartz particles induced DNA double-strand breakage, which was inhibited by catalase. In an argon atmosphere DNA damage was suppressed, showing that molecular oxygen is required for quartz-induced DNA damage. Quartz particles also caused dose-dependent lipid peroxidation as measured by malondialdehyde formation. Superoxide dismutase, catalase, and sodium benzoate inhibited quartz-induced lipid peroxidation by 49, 52,...

Dietary Cooked Navy Beans and Their Fractions Attenuate Colon Carcinogenesis in Azoxymethane-Induced Ob/Ob Mice

Based on the protective effects of cooked dry bean consumption in a human intervention study, we evaluated which fraction of cooked dry beans is responsible for its cancer-preventive effects. Cooked navy beans (whole beans), the insoluble fraction (bean residue) or soluble fraction of the 60% (vol:vol) ethanol extract of cooked navy beans (bean extract), or a modified AIN-93G diet (16.6% fat including 12.9% lard) as control diet were fed to 160 male obese ob/ob mice after 2 azoxymethane injections. In comparison to control-fed mice, dysplasia, adenomas, or adenocarcinomas were detected in fewer mice on either bean fraction diet (percent reduction from control: whole beans 54%, P = 0.10; bean residue 81%, P = 0.003; bean extract 91%, P = 0.007), and any type of colon lesions, including focal hyperplasia, were found in fewer mice on each of the 3 bean diets percent reduction from control: whole bean 56%, P = 0.04; bean residue 67%, P = 0.01; bean extract 87%, P = 0.0003. These results suggest that both the soluble and the insoluble fraction of the extract contribute to the cancer-protective effect of cooked navy beans.

Generation of thiyl and ascorbyl radicals in the reaction of peroxynitrite with thiols and ascorbate at physiological pH

Electron spin resonance (ESR) spin trapping was utilized to investigate the reaction of peroxynitrite with thiols and ascorbate at physiological pH. The spin trap used was 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The reaction of peroxynitrite with DMPO generated 5,5-dimethylpyrrolidone-(2)-oxy-(1) (DMPOX). Formate enhanced the peroxynitrite decomposition but did not generate any detectable amount of formate-derived free radicals. Thus, the spin trapping measurements provided no evidence for hydroxyl (.OH) radical generation in peroxynitrite decomposition at physiological pH. Thiols (glutathione, cysteine, and penicillamine) and ascorbate reacted with peroxynitrite to generate the corresponding thiyl and ascorbyl radicals. The one-electron oxidation of thiols by peroxynitrite may be one of the important mechanisms for peroxynitrite-induced toxicity and ascorbate may provide a detoxification pathway.

RNA Metabolism in Tracheal Epithelium: Alteration in Hamsters Deficient in Vitamin A

The electrophoretic pattern of RNA molecules that are synthesized in vitro in tracheal epithelium from hamsters deficient in vitamin A differs from that of RNA synthesized in normal, pair-fed control hamsters. There is less RNA of low electrophoretic mobility in the epithelial cells deficient in vitamin A. This alteration is reversed after the deficient animals have been treated with vitamin A.

Antioxidant activity of tetrandrine and its inhibition of quartz-induced lipid peroxidation.

Tetrandrine is a benzylisoquinoline alkaloid that has been used in China as an antifibrotic drug to treat the lesions of silicosis. Its mechanism in the treatment of silicosis is unclear. Electron spin resonance (ESR) spin trapping was employed to investigate the antioxidant properties of tetrandrine. The spin trap used was 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Tetrandine efficiently reacted with hydroxyl (.OH) radicals with a reaction rate of approximately 1.4 x 10(10) M-1 s-1. The .OH radicals were generated by the Fenton reaction [Fe(II) + H2O2) as well as by reaction of chromium(V) with H2O2. Similar results were obtained using .OH radicals generated by reaction of freshly fractured quartz particles with aqueous medium. Tetrandrine also scavenged superoxide (O2-) radicals produced from xanthine/xanthine oxidase. The effect of tetrandrine on lipid peroxidation induced by freshly fractured quartz particles was evaluated using linoleic acid as a model lipid. The results showed that tetrandrine caused a significant inhibition on freshly fractured quartz-induced lipid peroxidation.

Neoplastic transformation by quartz in the BALB/3T3/A31-1-1 cell line and the effects of associated minerals.

Quartz, the most common form of crystalline silica, was tested quantitatively for neoplastic transformation in the mouse embryo cell line, BALB/3T3/A31-1-1. Five quartz dust samples of respirable size [Min-U-Sil 5 (MQZ); hydrofluoric-acid-etched MQZ (HFMQZ); Chinese standard quartz (CSQZ); DQ12; and F600] all induced significant levels of neoplastic transformation, showing dose-dependent increases in the frequency of morphologically transformed foci at lower tested doses and a plateau level of response at higher doses. The plateau levels reached by the five tested samples did not differ substantially (maximum transformation frequencies per 10(5) cells ranging from 53.2 for MQZ to 28.3 for HFMQZ). F600 had minimal cytotoxicity but transforming activity comparable to the other samples. Cells from all tested transformed foci, when injected s.c. in nude mice, grew as sarcomas. Cytogenetic analysis showed that all tested silica-transformed cell lines had acquired one to five additional marker chromosomes, of types not seen in untreated control lines, indicative of induced chromosomal translocations and amplification. Increased expression of one or more of five genes (p53, myc, H-ras, K-ras, and abl) was observed in several quartz-transformed cell lines. No transforming activity was found for hematite and anatase (both nontoxic), and for rutile (more toxic than MQZ). Combined exposure (1:1 w/w per unit culture area) of each of these dusts with MQZ showed that hematite and anatase inhibited MQZ toxicity as well as transformation, whereas rutile markedly enhanced MQZ toxicity but not MQZ-induced transformation.

Transforming growth factor beta expression and transformation of rat lung epithelial cells by crystalline silica (quartz)

Crystalline silica (quartz) induces silicosis and associated peripheral lung carcinomas in rats. The role and pattern of expression of transforming growth factor (TGF)‐β1/β2 mRNA transcripts were investigated in the fetal rat lung epithelial cell line FRLE, its neoplastic transformants and derived tumors in athymic nude mice. FRLE cells, treated with 100 μg/cm2 of quartz in serum‐free medium, gave rise to phenotypically altered, tumorigenic cells. Quartz‐treated, transformed and tumorigenic cells, subcultured directly (QTT‐C1) or after growth in soft agar (QTT‐C2), formed tumors in athymic nude mice (QTT‐T1). Cells subcultured from the tumors (QTT‐TIC) were also tumorigenic in nude mice (QTT‐T2). QTT‐T1 and QTT‐T2 tumors were poorly differentiated carcinomas with variable amounts of extracellular matrix‐associated TGF‐β1 and desmoplasia. For comparison, a tumorigenic cell line derived from FRLE cells transformed with a mutated K‐ras plasmid (RT‐CI) and cells subcultured from a corresponding nude mouse tumor (RT‐TI) and designated RT‐TIC were used. Whereas TGF‐β1 and TGF‐β2 inhibited the growth of QTT‐TIC and FRLE cells in a dose‐dependent fashion. RT‐TIC cells, containing an activated ras gene, were relatively unaffected. TGF‐β1 and TGF‐β2 mRNAs were expressed at higher levels in QTT‐TIC cells than in FRLE and RT‐TIC cells, and there was an increase in TGF‐βtype II receptor (TGF‐βR) mRNA expression in QTT‐TIC and RT‐TIC cells compared to FRLE cells. Carcinomas in nude mice derived from QTT and RT cells and silicosis‐associated lung carcinomas induced in rats by intra‐tracheal quartz did not express either active or latent forms of TGF‐β1 protein on immunohistochemistry. The disparity between TGF‐β1 mRNA and TGF‐β1 protein expression in QTT tumors may be due to post‐transcriptional regulation of TGF‐β1.

Laryngeal cancer in non-smoking and non-drinking patients.

XAVIER LEÓN, ALESSANDRA RINALDO, UMBERTO SAFFIOTTI and ALFIO FERLITO From the Department of Otolaryngology, Hospital de Santa Creu i Sant Pau, Barcelona, Spain, Department of Surgical Sciences, ENT Clinic, University of Udine, Udine, Italy and Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA and Department of Environmental and Occupational Health, The George Washington University, Washington, D.C., USA