DNA adduct burden and tobacco carcinogenesis

Sanguinarine and chelerythrine: assessment of safety on pigs in ninety days feeding experiment

Sanguinaria canadesis, Chelidonium majus and Macleya cordata have been used for centuries as alternative medicines. Currently the extracts from these medicinal plants are components of veterinary and human phytopreparations, and of oral-hygiene agents. Sanguinarine and chelerythrine (SA/CHE) are biologically active components of these extracts. They display distinct antibacterial and anti-inflammatory properties, but, on the other hand, they have been reported as having adverse effects - genotoxicity and hepatotoxicity. This paper is aimed at evaluation of the effects of daily administration of the extract from Macleya cordata (2 mg and 100 mg in 1 kg feed, sanguinarine:chelerythrine 3:1) in the diet on the health status of swine. After 90-day administration, alkaloids were retained to a different extent in tissues. The highest SA/CHE retention was detected in the gingiva (0.55 microg/g) and liver (0.15 microg/g), no SA/CHE were detected in muscles. Plasma SA levels attained 0.11 microg/ml. Treated animals did not display any results of hematological, biochemical or histological assay different from controls. A (32)P-postlabeling assay proved that no DNA-adducts with SA/CHE were detected in pig livers. We did not observe any symptom linked to epidemic dropsy syndrome often attributed to sanguinarine. In conclusion, an average daily oral dose of alkaloids up to 5 mg per 1 kg animal body weight proved to be safe.

Genotypic analysis of pulmonary Langerhans cell histiocytosis

Reported studies show that the systemic form of Langerhans cell histiocytosis (LCH) is a clonal expansion of Langerhans cells (LC) associated with aberrant expression of several oncogenes or tumor-suppressor genes. LCH of the lung is a heterogenous group of lesions thought to be a reactive rather than neoplastic process. The histogenesis of the LCH of the lung is uncertain, and to date there are no studies investigating its underlying molecular abnormalities. We performed comparative genotypic analysis by using allelic loss (LOH) of polymorphic microsatellite markers associated with tumor suppressor genes. Fourteen cases of formalin-fixed, paraffin-embedded LCH of the lung were studied. Microdissection of a total of 26 nodules from 14 patients and paired reference lung tissue was performed under stereomicroscopic visualization. To evaluate allelic loss, we used a panel of 11 polymorphic microsatellite markers that were situated at or near tumor suppressor genes on chromosomes 1p, 1q, 3p, 5p, 9p, 17p, and 22q. The PCR products were analyzed by using capillary electrophoresis to identify germline heterozygous alleles and LOH. Allelic loss at 1 or more tumor suppressor gene loci was identified in 19 of 24 nodules. The total fractional allelic loss (FAL) ranged from 6% (1q) to 41% (22q), with a mean of 22%. The FAL in individual cases ranged from 0 (7 nodules) to 57% (1 nodule). Fifteen discordant allelic losses at 1 to 3 chromosomal loci were identified in 8 patients with multiple synchronous nodules. Our results show that LOH of tumor suppressor genes is present in the LCH of the lung, and they indicate that the putative tumor suppressor genes situated on chromosomes 9p and 22q may play a role in the development of a subset of the LCH of the lung.

Monitoring of DNA Adducts in Humans and 32P-Postlabelling Methods. A Review

DNA adduct formation in humans is a promising biomarker for elucidating the molecular epidemiology of cancer. For detection of DNA adducts, the most widely used methods include mass spectroscopy, fluorescence spectroscopy, immunoassays and 32P-postlabelling. Among them, the 32P-postlabelling method appears to meet best the criteria of sensitivity and amount of DNA needed, and, therefore, is one of the most appropriate methods for biomonitoring of human DNA adducts. Most classes of carcinogens have been subjected to 32P-postlabelling analysis, ranging from bulky and/or aromatic compounds to small and/or aliphatic compounds; it has also been used, with modifications, to detect apurinic sites in DNA, oxidative damage to DNA, UV-induced photodimers and, to a lesser extent, DNA damage caused by cytotoxic drugs. It has been used in human biomonitoring studies to detect DNA damage from occupational exposure to carcinogens, and also from environmental (i.e. non-occupational) exposures. It has also led to the discovery of the presence of numerous modifications in DNA arising from endogenous processes. The principle of the method is the enzymatic digestion of DNA to nucleotides, 5'-labelling of these nucleotides with an isotopically labelled phosphate group, and the resolution, detection and quantitation of the labelled products. Since the development of the original procedure in the early 1980s, many methods have been developed to increase the sensitivity by enrichment of modified nucleotides prior to labelling. The review presents the individual 32P-postlabelling techniques (standard procedure, enrichment methods) and a critical evaluation of these assays, besides reviewing the applications of the method to different DNA modifications, and its utilization in human biomonitoring studies. A review with 179 references.

The molecular basis of lung cancer: molecular abnormalities and therapeutic implications

Lung cancer is the number one cause of cancer-related death in the western world. Its incidence is highly correlated with cigarette smoking, and about 10% of long-term smokers will eventually be diagnosed with lung cancer, underscoring the need for strengthened anti-tobacco policies. Among the 10% of patients who develop lung cancer without a smoking history, the environmental or inherited causes of lung cancer are usually unclear. There is no validated screening method for lung cancer even in high-risk populations and the overall five-year survival has not changed significantly in the last 20 years. However, major progress has been made in the understanding of the disease and we are beginning to see this knowledge translated into the clinic.

In this review, we will summarize the current state of knowledge regarding the cascade of events associated with lung cancer development. From subclinical DNA damage to overt invasive disease, the mechanisms leading to clinically and molecularly heterogeneous tumors are being unraveled. These lesions allow cells to escape the normal regulation of cell division, apoptosis and invasion. While all subtypes of non-small cell lung cancer have historically been treated the same, stage-for-stage, recent technological advances have allowed a better understanding of the molecular classification of the disease and provide hypotheses for molecular early detection and targeted therapeutic strategies.

Tobacco carcinogens, their biomarkers and tobacco-induced cancer

The devastating link between tobacco products and human cancers results from a powerful alliance of two factors - nicotine and carcinogens. Without either one of these, tobacco would be just another commodity, instead of being the single greatest cause of death due to preventable cancer. Nicotine is addictive and toxic, but it is not carcinogenic. This addiction, however, causes people to use tobacco products continually, and these products contain many carcinogens. What are the mechanisms by which this deadly combination leads to 30% of cancer-related deaths in developed countries, and how can carcinogen biomarkers help to reveal these mechanisms?