The Effect of Epigallocatechin gallate on Cross-talk Between Autophagy and Apoptosis in NALM-6 Cell Line

Abstract

Background: Acute lymphoblastic leukemia is a prevalent hematological malignancy in 2-5-year-old children. Chemotherapy, as the most common treatment for ALL, is not usually responsive. Epigallocatechin gallate (EGCG), a small molecule extracted from green tea, has significant effects on tumor cells through different mechanisms, such as DNA damage, cell cycle arrest, oxidative stress, apoptosis, and autophagy. In this study, we investigated the impact of EGCG on autophagy and apoptosis in NALM-6 cell line. Methods and results: Cell viability and apoptosis were assessed by MTT and Trypan blue exclusion assay, and flow cytometry. It was shown that EGCG remarkably inhibited proliferation, reduced cell viability, and induced apoptosis in NALM-6 cell line (P<0.05). In addition, real-time PCR and western blot analysis were used to examine autophagy. It was observed that EGCG resulted in a 4-fold increase in LC3 protein level (P<0.05) while reducing the mRNA expression level of LC3B, P62/SQSTM1, and Atg2B genes (P<0.01). It also caused around 1.3-fold increase in DRAM1 mRNA expression level (P<0.05). Finally, it was indicated that the inhibition of autophagy affects apoptosis neither in untreated nor treated cells with EGCG.Conclusion: These results show that EGCG can induce apoptosis and autophagy in NALM-6 cell line while inhibition of autophagy cannot affect apoptosis in this cell line.