EGCG's anticancer potential unveiled: triggering apoptosis in lung cancer cell lines through in vitro investigation

Abstract

Background: Novel treatment techniques are needed since lung cancer is still a major worldwide health concern. Green tea contains a component called epigallocatechin-3-gallate (EGCG), which has demonstrated potential anticancer properties. This work sought to understand how EGCG affects the phosphatidylinositol-3-kinase protein kinase B (PI3K/Akt) signaling pathway, which in turn causes apoptosis in H1299 lung cancer cells.

Methods: In this experiment, multiple dosages of EGCG were applied to five H1299 cells and five A549 cell lines for a duration of 72 h. Apoptotic pathways, cellular responses, and protein expression levels were investigated in relation to EGCG by morphological, biochemical, and proliferation/migration investigations.

Results: In H1299 and A549 cells, EGCG raised apoptosis rates and, in a dose-dependent way, hindered cell growth. The levels of phosphorylated Akt (p-Akt) and PI3K (p-PI3K) dramatically reduced following EGCG administration, despite no significant alterations in Akt and PI3K expressions. These results imply that EGCG inhibits the activation of the PI3K/Akt signaling pathway, which in turn causes apoptosis in H1299 and A549 cells.

Conclusion: The research provides insights into the effects of EGCG on proliferation and migratory inhibition, as well as highlighting its potential to induce apoptosis in lung cancer cells. These results support EGCG's promise as a therapeutic agent in the treatment of lung cancer and further our understanding of the processes underlying its anticancer activities.

Keywords: A549 cells; Apoptosis rate; Cell proliferation; Epigallocatechin -3- gallate (EGCG); H1299 cell; Lung cancer; Protein expression.

Figure 1. Morphological assessment of H1299 cells after 7 days of culture (magnification of 20X).

This figure presents the morphological characteristics of H1299 cells, a non-small cell lung cancer cell line, observed under a phase-contrast microscope. The typical polygonal shape and size H1299 cells at 70% confluence.

Figure 2. Morphological assessment of A549 cells after 7 days of culture (magnification of 20X).

This figure illustrates the morphological characteristics of A549 cells, a human lung adenocarcinoma cell line, after 7 days of culture. The cell line displays the typical fibroblast-like morphology, characterized by elongated shapes and a relatively high degree of motility. This assessment provides valuable insights into the growth dynamics and cellular characteristics of A549 cells in culture.

Figure 3. Inhibitory effect of EGCG on cell viability.

(A–B) The inhibitory effects of different concentrations of epigallocatechin gallate (EGCG) (0, 5, 30, and 50 µM) on cell viability, as measured by % inhibitory effect. Increasing concentrations of EGCG demonstrate a dose-dependent decrease in cell viability in both conditions represented in (A) and (B).

Figure 4. Effect of EGCG on apoptosis of A-H1299 cell line B- A549 cell line.

This figure illustrates the effects of epigallocatechin gallate (EGCG) on apoptosis in H1299 (A) and A549 (B) cell lines. An increase in EGCG concentration showed a decrease in cell viability by MTT assay.

Figure 5. Flow cytometric analysis of cell apoptosis using annexin V-FITC and PI staining.

(A) Control group showing low apoptosis rates. (B) Moderate apoptotic response at 30 µM EGCG concentration. (C) High apoptosis rate after treatment with 50 µM EGCG. The dot plots illustrate the distribution of cells in different stages of apoptosis: lower-left quadrant represents live cells, lower-right quadrant early apoptosis, upper-right quadrant late apoptosis, and upper-left quadrant necrotic cells.

Figure 6. Western blot analysis of PI3K/AKT signaling pathway in response to EGCG treatment.

(A–B) Western blot images representing the protein expression levels of PI3K, phosphorylated PI3K (p-PI3K), AKT, and phosphorylated AKT (p-AKT) across different EGCG concentrations (0, 5, 30, and 50 µM). GAPDH was used as the loading control.