Benzo(a)pyrene-induced cytotoxicity, cell proliferation, DNA damage, and altered gene expression profiles in HT-29 human colon cancer cells.

In the US alone, around 60,000 lives/year are lost to colon cancer. In order to study the mechanisms of colon carcinogenesis, in vitro model systems are required in addition to in vivo models. Towards this end, we have used the HT-29 colon cancer cells, cultured in Dulbecco's Modified Eagle Medium (DMEM), which were exposed to benzo(a)pyrene (BaP), a ubiquitous and prototypical environmental and dietary toxicant at 1, 10, 100 nM and 1, 5, 10, and 25 μM concentrations for 96 h.

Metabolism of benzo(a)pyrene by subcellular fractions of gastrointestinal (GI) tract and liver in Apc(Min) mouse model of colon cancer.

Given the fact that increased dietary intake of polycyclic aromatic hydrocarbons (PAHs; a family of environmental toxicants) leads to the formation and development of colon tumors, the ability of the gastrointestinal tract to process these compounds is important from the viewpoint of toxicity/carcinogenesis. Benzo(a)pyrene (BaP), a prototypical PAH compound is released into the environment from automobile exhausts, cigarette smoke, and industrial emissions. Additionally, considerable intake of BaP is expected in people who consume barbecued foods and a diet rich in saturated fat.

Tumor microsomal metabolism of the food toxicant, benzo(a)pyrene, in ApcMin mouse model of colon cancer.

The present study was conducted to investigate whether colon tumors were capable of metabolizing benzo(a)pyrene (BaP), and fluoranthene (FLA), two toxicants that belong to the polycyclic aromatic hydrocarbon family of compounds. Microsomes were isolated from the colon tumors of Apc( Min ) mice that received subchronic doses of 50 μg/kg BaP and incubated with either BaP or FLA (3 μM each) alone or in combination and appropriate control groups that received nothing. Subsequent to incubation, samples were extracted with ethyl acetate and analyzed for BaP and FLA metabolites by reverse-phase HPLC equipped with fluorescence detection.

Polycyclic aromatic hydrocarbons and digestive tract cancers: a perspective.

Cancers of the colon are most common in the Western world. In majority of these cases, there is no familial history and sporadic gene damage seems to play an important role in the development of tumors in the colon. Studies have shown that environmental factors, especially diet, play an important role in susceptibility to gastrointestinal (GI) tract cancers.

Comparative evaluation of different cell lysis and extraction methods for studying benzo(a)pyrene metabolism in HT-29 colon cancer cell cultures.

Lysis and extraction of cells are essential sample processing steps for investigations pertaining to metabolism of xenobiotics in cell culture studies. Of particular importance to these procedures are maintaining high lysis efficiency and analyte integrity as they influence the qualitative and quantitative distribution of drug and toxicant metabolites in the intra- and extracellular milieus. In this study we have compared the efficiency of different procedures viz.

Genotoxicity in filling station attendants exposed to petroleum hydrocarbons.

Objectives: Biomonitoring of exposure in workplaces has gained importance in evaluation of human health hazards. Since occupational exposure to petroleum hydrocarbons may have deleterious effects, genotoxicity risk among 200 fuel filling station attendants (FFSAs) and 200 matched controls was investigated.

Methods: The probable genetic damage was determined by comet assay and micronucleus test in peripheral blood lymphocytes (PBL) of study subjects.