Heme oxygenase-l (HO-l) exhibits cyt oprotective effects in many different cell types and is induced by nicotine exposure in human gingival fibroblasts‘ However‘ therole of HO- l in cancer cells exposed to nicotine has not previously been descnbed We investigated the effects of nicotine on HO-l protein expression and cell viability in immortalized (IHOK) and malignant (HN12) human ora l keratinocyte cells using the MTT assay and Western blotting. We al so examined the involvement of t he phosphoinosit ide-3-0H- kinase (PI3K), mitogen-acti vated protein kinase (MAPK) , and nucJear factor-κ B (NF-κ B) signaling pathways in nicotine-induced cytotoxicity and HO- l levels in IHOK and HN12 cell s‘ Nicotine induced HO- l pro ducti on and had cytotoxic effects on cells in both a concentration- and time-dependent manner. Nicotine-induced cytotox icity and accumulation of HO- l were greater in JJ-IOK cells than in HN12 cells Molecular inhibitors of the ERK, p38 MAP kinase, PI3K, and NF-κ B signaling pathways blocked the cytotoxic effects and induction of J-IO-l expression by nicotine. Treatmen t with an t ioxida nts (bil irubin, N-acetyl cysteine) protected cells against nicotine-induced cytotoxicity and blocked the upregula tion of J-IO- l, the effects of which were more pronounced in II-IOK cells than in HN12 cells Collecti vely, these results suggest that J-IO- l plays a principal role in the protective response to nicotine in oral cancel and immortalized keratinocytes. Moreover, the addition of exogenous antioxidants may help to protect oral epithelial cells as chemopreventive agents against nicotine-induced oxidative stress.

Heme oxygenase-l (HO-l) exhibits cyt oprotective effects in many different cell types and is induced by nicotine exposure in human gingival fibroblasts‘ However‘ therole of HO- l in cancer cells exposed to nicotine has not previously been descnbed We investigated the effects of nicotine on HO-l protein expression and cell viability in immortalized (IHOK) and malignant (HN12) human ora l keratinocyte cells using the MTT assay and Western blotting. We al so examined the involvement of t he phosphoinosit ide-3-0H- kinase (PI3K), mitogen-acti vated protein kinase (MAPK) , and nucJear factor-κ B (NF-κ B) signaling pathways in nicotine-induced cytotoxicity and HO- l levels in IHOK and HN12 cell s‘ Nicotine induced HO- l pro ducti on and had cytotoxic effects on cells in both a concentration- and time-dependent manner. Nicotine-induced cytotox icity and accumulation of HO- l were greater in JJ-IOK cells than in HN12 cells Molecular inhibitors of the ERK, p38 MAP kinase, PI3K, and NF-κ B signaling pathways blocked the cytotoxic effects and induction of J-IO-l expression by nicotine. Treatmen t with an t ioxida nts (bil irubin, N-acetyl cysteine) protected cells against nicotine-induced cytotoxicity and blocked the upregula tion of J-IO- l, the effects of which were more pronounced in II-IOK cells than in HN12 cells Collecti vely, these results suggest that J-IO- l plays a principal role in the protective response to nicotine in oral cancel and immortalized keratinocytes. Moreover, the addition of exogenous antioxidants may help to protect oral epithelial cells as chemopreventive agents against nicotine-induced oxidative stress.

Sulfur is commonly used in Asia as a n herba l medicine to treat infl ammation and cancel‘. and potent chemopreventive effects have been demonstrated in various in vivo and in vitromodels for sulfur-containing compounds found in naturally occun‘ ing products. Here, we report the growth inhibitory and apoptosis-related effects of a newly developedhigh- purity eclible sulfur (ES) on immortali zecl human oral keratinocytes (IHOKs) and on oral cancer cells representing two stages of oral can cer (HN4‘ HN12) basecl on an 3-(4. 5-Dimethylt hiazol-2-yl)-2.5-cliphenyl tetrazolium bromide (MTT) a ssay, Western blotting, cell cycle analysis, ancl nuclear staining. The puri ty of the ES used in th is s tucly was verified by high performance liquid chromat ography (HPLC) , amino acid analysis and energy di spersive spectroscopy (EDS). ES inhibitecl the proliferation of immor talized and malignant oral kerati nocytes in a dose- and time-dependent manner FITC-Annexin V staining. DNA fragmentation testing. and Hoechst 33258 staining revealed that ES inhibits cell growth via apoptosis . ES blocked cell-cycle progression at the sub- Gl phase, with decreased expression 0 1' cyclins Dl, D2, and E, and t heir activating partners cdk2, cdk4, and cdk6‘ and a concomitant induction of p53 and p21/WAF1. Furthermore, ES treatment increased the cytosolic level of cytochrome c a nd resulted in caspase-3 activation‘ and thi s effect was correlated wi th Bax up- regulation and Bcl-2 down- regulation Taken together, these clata suggest that ES is a potential chemopreventive and chemotherapeutic agent for oral cancel

Insulin-like growth factor II (IGF2) and H19 genes are mutually imprinted genes which may be responsible for abnormalities in the cloned fetuses and offspring. This study was performed to identify putative differentially methylated regions (DMRs) of porcine H19 locus and to explore its genomic imprinting in in vitro fertilized (IVF) and somatic cell nuclear transferred (SCNT) embryos. Based on mice genomic data, we identified DMRs on H19 and found porcine H19 DMRs that included three CTCF binding sites. Methylation patterns in IVF and SCNT embryos at the 2-, 4-, 8～16-cells and blastocyst stages were analyzed by BS (Bisulfite Sequencing)-PCR. The CpGs in CTCF1 was significantly unmethylated in the 2-cell stage IVF embryos. However, the 4- (29.1%) and 8～16-cell (68.2%) and blastocyst (48.2%) stages showed higher methylation levels (p<0.01). On the other hand, SCNT embryos were unmethylayted (0～2%) at all stages of development. The CpGs in CTCF2 showed almost unmethylation levels at the 2-, 4- and 8～16-cell and blastocyst stages of development in both IVF (0～14.1%) and SCNT (0～6.4%) embryos. At all stages of development, CTCF3 was unmethylated in IVF (0～17.3%) and SCNT (0～1.2%) embryos except at the blastocyst stage (54.5%) of IVF embryos. In conclusion, porcine SCNT embryos showed an aberrant methylation pattern comprised to IVF embryos. Therefore, we suggest that the aberrant methylation pattern of H19 loci may be a reason for increased abnormal fetus after embryo transfer of porcine SCNT embryos.