AIM To determine NO, NO synthase (NOS) and NOSmRNA of the esophageal carcinoma cells (SHEEC1)in apoptotic process induced by As2O3 and to explore the relationship between NO and apoptosis.METHODS The apoptosis of the cell line (SHEEC1) was induced by arsenite (As2O3, 5 μmol/L and10 μmol/L). In the process, at 2 h, 4 h, 8 h, 16 h and 24 h after administration of As2O3, NO production incultural medium was detected quantitatively by spectrophotometry; NOS Ⅱ was detected byimmunohistochemistry and NOS mRNA by in situ hybridization (ISH). The cells at endpoint of theexperiment were examined under transmitted electron microscope (TEM) for apoptosis.RESULTS The amount of NO released from SHEEC1 were increased from the basal condition (0.68×10-2μmol/L) up to the high level (2.38×10-2μmol/L) at h 16. The increment of NOS Ⅱ was found afteradministration of As2O3; the intracytoplasmic ISH signals of NOSmRNA in small size was found firstly at4 h, and then became highly predominant. Apoptotic changes of SHEEC1 occurred at 24 h under TEM.CONCLUSION After administration of As2O3, NO released from cultured SHEEC1 cells was detected withincreasing amount up to 16 h. The expression of NOS H and transcription of NOSmRNA are upregulated.The present findings suggest a concept that the NO may be a mediated and effective factor in apoptosisinduced by As2O3,

Cancer as an Environmental Disease:Liver Cancer in Bangladesh

Although cancer is considered a common human genetic disease,there has been no significant evidence showing that it is caused by DNA mutations.DNA mutations as drivers or passengers associated with cancer development have been described in many reports.In addition,it has been shown that environmental factors can induce cancer,and thus,cancer can be considered an environmental disease.Liver cancer has become prevalent in Bangladesh,most l ikely due to environmental pollution as the groundwater is naturally contaminated with toxic levels of arsenic.The harm caused by contamination has not been l imited to l iver cancer,as other cancer types have been reported.Moreover,in worst-case scenarios,intake of arsenic has even caused death.As arsenic is usually found in groundwater worldwide,anyone can be affected.However,intake of only a tiny amount is not considered poisonous.Bangladesh has been greatly suffering from arsenic contamination,and as a result,toxicity and cancer have become prevalent.