Black tea polyphenols restrict benzopyrene-induced mouse lung cancer progression through inhibition of Cox-2 and induction of caspase-3 expression.

Lung cancer is one of the leading causes of cancer related death in most developed and many developing countries of the world. Due to lack of validated screening methods and poor prognosis, treatment of lung cancer has not improved significantly over the last two decades. Therefore the risk of the disease needs to be minimized by preventive measures. One approach for lung cancer prevention envisages reversal or restriction of precancerous lesions by chemopreventive intervention. It demands a deeper understanding of the pathogenesis of the disease and identification of the ideal point of intervention. In the present investigation, tea components, epigallocatechin gallate (EGCG) and theaflavins (TF) were assessed for their chemopreventive potential when administered in the post initiation phase of lung carcinogenesis in an experimental mouse model. Histopathological changes in lungs of mice administered benzo(a)pyrene (BP) were followed serially and correlated with the expression of Cox-2, caspase-3 and caspase-7, which play key roles in histopathogenesis of neoplasia. The observations strongly indicate that both EGCG and TF can influence the expression of these genes to modulate the process of carcinogenesis, resulting in delayed onset and lowered incidence of pre-invasive lung lesions.