Green tea catechin, epigallocatechin-3-gallate, attenuates the cell viability of human non-small-cell lung cancer A549 cells via reducing Bcl-xL expression

Abstract

Clinical and epidemiological studies have indicated that the consumption of green tea has a number of beneficial effects on health. Epigallocatechin-3-gallate (EGCg), the major polyphenolic compound present in green tea, has received much attention as an active ingredient. Among the numerous promising profiles of EGCg, the present study focused on the anticancer effects. Apoptosis induced by EGCg and subsequent cell growth suppression have been demonstrated in a number of cell culture studies. However, the underlying mechanism of apoptotic cell death remains unclear. Thus, the aim of the present study was to identify the major molecule that mediates proapoptotic cell death by EGCg. The effect of EGCg on cell proliferation and the induction of mRNA that modulates apoptotic cell death was evaluated in the A549 human non-small-cell lung cancer cell line. In addition, morphological changes were assessed by microscopy in A549 cells that had been treated with 100 μM EGCg for 24 h. The MTT assay revealed that cell proliferation was significantly reduced by EGCg in a dose-dependent manner (3–100 μM). The mRNA expression level of B-cell lymphoma-extra large (Bcl-xL) was decreased in A549 cells following 24 h incubation with 100 μM EGCg. Therefore, the results indicated that the inhibition of cell proliferation by EGCg may be achieved via suppressing the expression of the cell death-inhibiting gene, Bcl-xL.

Green tea polyphenols and their potential role in health and disease

“…The mechanism of apoptotic cell death is believed to be through down-regulation and/or suppression of cell deathinhibiting gene Bcl-xL (Sonoda et al 2014). A down-regulation of ku70 by interrupting its binding with Bax mRNA and drug-metabolizing enzymes such as cytochrome P450 and peroxidoredoxin-V has been suggested as possible mechanism of action for cancer treatment Maliakal et al 2011;Ren et al 2011).…”

Responses of Different Cancer Cells to White Tea Aqueous Extract

“…Most previous studies evaluated the capability of teas inhibiting the proliferation of cancer cells or tumor growth utilizing either ethanol extracts or the main bioactive ingredient of teas as agents, such as catechins and EGCG (Chen et al., 2015; Shi et al., ; Sonoda et al. ; Tsai and Chen ). Tea remains one of the most popular beverages in the world, and the most common method of tea infusion preparation is by placing tea leaves or leaf powder into boiling water.…”

Molecular mechanisms of natural compounds in cell death induction and sensitization to chemotherapeutic drugs in lung cancer

“…The other polyphenolic compound epigallocatechin‐3‐gallate (EGCG) that is mostly found in green tea ( Camellia sinensis ) leaves, has been shown to be beneficial for human health and to have antioxidant and anticancer activities (Kim, Quon, & Kim, ). It has shown that mRNA expression of antiapoptotic Bcl‐xL in A549 lung cancer cells was significantly downregulated after treatment with EGCG in vitro (Sonoda et al, ). Considering NF‐κB signaling governs Bcl‐xL transcription, EGCG suppresses Bcl‐xL mRNA and protein expression through the regulation of NF‐κB signaling (Sonoda et al, ).…”

“…It has shown that mRNA expression of antiapoptotic Bcl‐xL in A549 lung cancer cells was significantly downregulated after treatment with EGCG in vitro (Sonoda et al, ). Considering NF‐κB signaling governs Bcl‐xL transcription, EGCG suppresses Bcl‐xL mRNA and protein expression through the regulation of NF‐κB signaling (Sonoda et al, ).…”