ACTA BIOLOGICA CRACOVIENSIA

16 TH INTERNATIONAL SYMPOSIUM ON CAROTENOIDS
Among other parameters we analyzed the formation of
thymine dimers, as a measure of direct DNA damage, in hdF
exposed to UVB-light in the presence and absence of the
carotenoids mentioned above. In cells preincubated with DHIR
and IR a significant decrease in formation of thymine dimers was
found, whereas the treatment with luteine had no effect. In the
alkaline Comet assay similar effects were determined for the aromatic
carotenoids. In this assay also luteine showed some protection
but less pronounced than DHIR and IR. Additionly, the
formation of reactive oxygen species (ROS) and intracellular zinc
release were determined. Both parameters were decreased in
cells preincubated with DHIR in comparison to untreated cells or
to those treated with luteine, which had no effect (Lutter et al.,
2010). The data provide further evidence for the high antioxidative
capacity of DHIR and confirm the hypothesis that DHIR is
protective against UVB-induced damage. As expected from the
structure DHIR acts as a multifunctional antioxidant with radical
scavenging and UVB absorbing properties.
REFERENCES
MARTIN HDD, KOCK S, SCHERRERS R, LUTTER K, WAGENER T, HUNDSDÖRFER
C, FRIXEL S, SCHAPER K, ERNST H, SCHRADER W, GÖRNER H,STAHL
W. 2009. 3,3´-Dihydroxyisoreniera-tene, a natural carotenoid
with superior antioxidant and photoprotective properties. Angew
Chem Int Ed 48: 400-403.
LUTTER K, DE SPIRT S, KOCK S, KRÖNKE KD, MARTIN HD, WAGENER T,
STAHL W. 2010. 3,3´-Dihydroxyisorenieratene prevents UV-induced
formation of reactive oxygen species and the release of proteinbound
zinc ions in human skin fibroblasts. Mol Nutr Food Res
54: 285-91.
4.6.
Beta-cryptoxanthin inhibits lung tumor by
suppressing α7 nicotinic receptor expression
and AKT activation in A/J mouse model
Anita Iskandar, Chun Liu, Hansgeorg Ernst,
Xiang-Dong Wang
Human Nutrition Research Center on Aging, Tufts University,
711 Washington St., Boston, MA, U.S.A., 02111,
Anita.iskandar@tufts.edu, Chun.liu@tufts.edu,
Xiang-dong.wang@tufts.edu
The efficacy of beta-cryptoxanthin (BCX) for lung carcinogenesis
has not been studied despite its association with a reduced risk
of lung cancer in epidemiological studies. The activation of nicotinic
acetylcholine receptor α7 subunit (α7-nAChR) and its downstream
pathway can promote lung tumor growth. We hypothesize
that BCX prevents the tobacco carcinogen-induced lung tumorigenesis
by targeting α7-nAChR signaling. Male A/J mice were randomly
assigned to six groups (n=16): the experimental arm
received the NNK (4-[N-nitrosomethylamino]-l-[3-pyridyl]-lbutanone)
injection with or without supplementation with BCX at
two doses (0.2 and 2 mg/kg/day); and the control arm without
NNK injection received the same BCX supplementation. The incidence
and multiplicity of lung tumor and α7-nAChR expression
and AKT activation were examined after 16 weeks post the carcinogen
injection. There were 52% and 63% reductions of lung
tumor multiplicity in mice supplemented with BCX at two doses,
respectively (P