Tonglian Decoction () arrests the cell cycle in S-phase by targeting the nuclear factor-kappa B signal pathway in esophageal carcinoma Eca109 cells

Objective: To investigate the anti-tumor activity and molecular mechanism of Tonglian Decoction (, TLD) on esophageal carcinoma Eca109 cells.

Methods: Eca109 cells were treated with TLD and its separated formulae, including the clearing-heat and detoxification formula (Q), activating-blood and promoting-qi formula (H) and nourishing-yin and blood formula (Z). Cell proliferation was measured using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, cell morphology was observed using a microscope, the cell cycle was measured using flow cytometry and the activity of the nuclear factor-kappa B (NF-κB) signal pathway was detected by Western blot.

Results: The half maximal inhibitory concentrations of TLD, Q and H were 386, 771 and 729 mg/L, respectively. TLD, Q and H significantly inhibited cell proliferation, with 69.43%, 60.84% and 61.90% of treated cells in the G phase of the cell cycle. The percentage of cells in S phase increased significantly after treatment with TLD, Q, and H compared with the control group (P<0.05), and TLD showed the strongest effect. Z had no influence on the cell cycle compared with the control group (P>0.05). Western blot detection indicated slight differences in the inhibition of the NF-κB pathway by the different formulae. TLD formula strongly inhibited IKKβ, NF-κB, interleukin-6 and tumor necrosis factor-α expression compared with the control group.

Conclusions: TLD inhibited Eca109 cell proliferation by arresting cells in S phase. The possible mechanism might be related to inhibiting the NF-κB transduction cascade. The combination of the herbs found in the three separate formulae, H, Q and Z, work synergistically in TLD to produce the inhibitory effects of TLD treatment on Eca109 proliferation.