WIR TUN GUTES UND SCHREIBEN DRÜBER:
UNSERE PUBLIKATIONEN

Retinoids are used in the clinical treatment of oral squamous carcinoma, including both early and late stages. Inter-individual variation in responsiveness, including a common insensitivity of advanced stages, suggest that changes in retinoid-related functions might characterize tumor development. To investigate a genetic basis for this hypothesis, an in vitro multi-step model of carcinogenesis involving normal (NOK), SV40 T antigen-immortalized (SVpgC2a) and malignant (SqCC/Y1) oral keratinocytes was analysed under identical culture conditions using micro-array technique (Affymetrix HG_U95A chip) for expression of 52 genes related to retinoid metabolism and actions.

Cigarette smoke is widely believed to increase free radical concentrations causing subsequent oxidative processes that lead to DNA damage and hence, to several diseases including lung cancer and atherosclerosis. Vitamin C is a reducing agent that can terminate free-radical-driven oxidation by being converted to a resonance-stabilized free radical. To investigate whether short-term supplementation with the antioxidants vitamin C and E decreases free-radical-driven oxidation and thus decreases DNA damage in smokers, we determined the frequency of micronuclei in lymphocytes in 24 subjects and monitored the electron paramagnetic resonance signal of ascorbate free radical formation in plasma. Further parameters comprised sister-chromatid exchanges and thiobarbituric acid-reactive substances.

BC. Two days after supplementation with 5 microM BC in MbetaCD, cellular BC levels reached a maximum of 140+/-11 pmol/microg DNA, leveling off to 100+/-15 pmol/microg DNA until day 8. Incubation with BC dissolved in THF/DMSO resulted in a lower BC uptake of 105+/-14 pmol/microg DNA and 64+/-20 pmol/microg DNA respectively. No cytotoxic effects of these formulations were detected. The results show that the MbetaCD formulation is an improved method for investigations of carotenoids and other lipophilic compounds in in vitro test systems compared to methods using organic solvents.