Search tips
Search criteria

Results 1-2 (2)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
1.  The Biology of Tobacco and Nicotine: Bench to Bedside 
Strong epidemiologic evidence links smoking and cancer. An increased understanding of the molecular biology of tobacco-related cancers could advance progress toward improving smoking cessation and patient management. Knowledge gaps between tobacco addiction, tumorigenesis, and cancer brought an interdisciplinary group of investigators together to discuss “The Biology of Nicotine and Tobacco: Bench to Bedside.” Presentations on the signaling pathways and pathogenesis in tobacco-related cancers, mouse models of addiction, imaging and regulation of nicotinic receptors, the genetic basis for tobacco carcinogenesis and development of lung cancer, and molecular mechanisms of carcinogenesis were heard. Importantly, new opportunities to use molecular biology to identify and abrogate tobacco-mediated carcinogenesis and to identify high-risk individuals were recognized.
PMCID: PMC3459058  PMID: 15824140
2.  Modulation of Carcinogen Activation and Detoxification by Novel Dithiolethione-Modified NSAIDs in Human Hepatoma HepG2 and Colon LS180 Cells 
Nonsteroidal anti-inflammatory drugs (NSAIDs) are promising chemopreventive agents against colon and other cancers. However the molecular basis mediated by NSAIDs for chemoprevention has not been fully elucidated. Environmental carcinogens induce DNA mutation and cellular transformation; therefore, we examined the effect of NSAIDs on carcinogenesis mediated by the aryl hydrocarbon receptor signaling pathway. In this study we investigated the activities of a new class of NSAIDs containing dithiolethione moieties (S-NSAIDs) on both arms of carcinogenesis.
Experimental Design
We investigated the effects of the S-NSAIDs, S-diclofenac and S-sulindac, on carcinogen activation and detoxification mechanisms in human hepatoma HepG2 and human colonic adenocarcinoma LS180 cells.
We found that S-diclofenac and S-sulindac inhibited the activity and expression of the carcinogen activating enzymes, cytochromes P-450 (CYP) CYP1A1, CYP1B1, and CYP1A2. Inhibition was mediated by transcriptional regulation of the aryl hydrocarbon receptor (AhR) pathway. The S-NSAIDs down-regulated carcinogen-induced expression of CYP1A1 heterogeneous nuclear RNA, a measure of transcription rate. Both compounds blocked carcinogen-activated AhR from binding to the xenobiotic responsive element as shown by chromatin immunoprecipitation. S-diclofenac and S-sulindac inhibited carcinogen-induced CYP enzyme activity through direct inhibition as well as through decreased transcriptional activation of the AhR. S-sulindac induced expression of several carcinogen detoxification enzymes of the glutathione cycle including glutathione S-transferase A2 (GSTA2), glutamate cysteine ligase catalytic subunit (GCLC), glutamate cysteine ligase modifier subunit (GCLM), and glutathione reductase (GR).
These results indicate that S-diclofenac and S-sulindac may serve as effective chemoprevention agents by favorably balancing the equation of carcinogen activation and detoxification mechanisms.
PMCID: PMC2755634  PMID: 19276279
aryl hydrocarbon receptor; CYP1A1; dithiolethione; sulindac; diclofenac

Results 1-2 (2)