Melatonin Inhibits Reactive Oxygen Species-Driven Proliferation, Epithelial-Mesenchymal Transition, and Vasculogenic Mimicry in Oral Cancer

Figure 4

Melatonin suppressed vasculogenic mimicry of oral cancer cells by blocking ROS-dependent ERK/Akt signaling. (a and b) Cal27 and FaDu cells were treated with melatonin (1 mM), NAC (5 mM), or vehicle (control) for 24 h. CMs were harvested to incubate HUVECs for 36 h. (a) Representative images of vascular mimicry. (b) The number of tubules was calculated. (c) Cal27 and FaDu cells were treated with melatonin (1 mM), NAC (5 mM), or vehicle (control) for 24 h. CMs were collected for VEGF measurement by using ELISA assay. (d) Cal27 and FaDu cells were treated with melatonin (1 mM) or vehicle (control) for 24 h. Representative Western blot results of p-Ak, Akt, p-ERK, ERK, HIF-1α, and VEGF. GAPDH was used as endogenous control. (e) Cal27 and FaDu cells were incubated with U0126 (20 μM), LY294002 (20 μM), NAC (5 mM), or the vehicle (control) for 24 h. The expression of p-ERK, ERK, p-Akt, Akt, HIF-1α, and VEGF was measured by Western blot assays. GAPDH was used as endogenous control. The ratios from the indicated proteins to GAPDH are indicated below the bands. Data are represented as the mean ± SD of three independent experiments. , versus control group. CMs: conditional medium; Ctrl: control; Mel: melatonin; NAC: N-acetyl-L-cysteine.

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