Tumor necrosis factor-related apoptosis-inducing ligand additive with Iodine-131 of inhibits non-small cell lung cancer cells through promoting apoptosis

Abstract

Non-small-cell lung cancer (NSCLC) accounts for ~80% of human lung cancer cases and is the most common cause of cancer-associated mortality worldwide. Reports have indicated that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Iodine-131 (I-131) can induce tumor cell apoptosis. The purpose of the present study was to investigate the additive efficacy of TRAIL and I-131 on NSCLC cells. The present study demonstrated that additive treatment of TRAIL and I-131 (TRAIL-I-131) significantly inhibited the growth and aggressiveness of NSCLC cells compared with single TRAIL or I-131 treatment. Results demonstrated that TRAIL-I-131 treatment induced apoptosis of NSCLC cells, with western blot analysis confirming that TRAIL-I-131 treatment increased proapoptotic Bad and Bax expression levels, while antiapoptotic Bcl-2 and Bcl-w protein levels were decreased in NSCLC cells. The present study demonstrated that TRAIL-I-131 treatment inhibited vascular endothelial growth factor (VEGF) and activator protein-1 (AP-1) in NSCLC cells. Potential mechanism analyses identified that TRAIL-I-131 treatment induced apoptosis of NSCLC cells through caspase-9 activation. In vivo assays revealed that TRAIL-I-131 treatment significantly inhibited NSCLC tumor growth and increased apoptotic bodies in tumor tissues. Immunohistology demonstrated that caspase-9 was upregulated and VEGF was downregulated in tumor tissues in TRAIL-I-131-treated tumors. In conclusion, these results indicate that TRAIL combined with I-131 promoted apoptosis of NSCLC through caspase-9 activation, which may be a promising anticancer therapeutic schedule for the treatment of NSCLC.

Keywords: Iodine-131; apoptosis; caspase-9; non-small cell lung cancer; tumor necrosis factor-related apoptosis-inducing ligand.

Figure 1.

Additive treatment of TRAIL and I-131 inhibits the growth and aggressiveness of NSCLC cells. (A) Additive treatment of TRAIL and I-131 inhibited the growth of A549 and H358 cells. (B and C) Additive treatment of TRAIL and I-131 achieved the maximum inhibitory effect for (B) A549 and (C) H358 cells after 48 h incubation. (D and E) Additive treatment of TRAIL and I-131 inhibited (D) migration and (E) invasion of A549 and H358 cells. All data are expressed as the mean and standard deviation, and were analyzed using one-way analysis of variance with Tukey HSD test. *P<0.05; **P<0.01; TRAIL vs. I-131, I-131 vs. control, combination vs. TRAIL. TRAIL, tumor necrosis factor-related apoptosis-inducing ligand; I-131, Iodine-131.

Figure 2.

Additive treatment of TRAIL and I-131 promotes apoptosis of NSCLC cells. (A) TRAIL-I-131 treatment promoted the apoptosis of A549 and H358 cells compared with either TRAIL, I-131 or control treatment. (B) TRAIL-I-131 treatment increased proapoptosic Bad and Bax protein levels, and decreased antiapoptotic Bcl-2 and Bcl-w protein levels in A549 and H358 cells. (C and D) TRAIL-I-131 treatment increased (C) caspase-8 and (D) caspase-9 activation in A549 and H358 cells. (E) TRAIL-I-131 treatment downregulated VEGF and AP-1 expression levels in A549 and H358 cells. All data are expressed as the mean and standard deviation, and were analyzed using one-way analysis of variance with Tukey HSD test. *P<0.05, TRAIL vs. I-131; **P<0.01, I-131 vs. control, combination vs. TRAIL. TRAIL, tumor necrosis factor related apoptosis-inducing ligand; I-131, Iodine-131; PI, propidium iodide; FITC, fluorescein isothiocyanate; VEGF, vascular endothelial growth factor; AP-1, activator protein-1.

Figure 3.

Additive treatment of TRAIL and I-131 downregulates metastasis-associated gene expression levels. (A and B) TRAIL-I-131 treatment downregulated FN, VN and EN mRNA expression levels in (A) A549 and (B) H358 cells. TRAIL-I-131 treatment downregulated FN, VN and EN protein expression levels in (C) A549 and (D) H358 cells. All data are expressed as the mean and standard deviation, and were analyzed using one-way analysis of variance with Tukey HSD test. *P<0.05; **P<0.01; I-131 vs. control, TRAIL vs. I-131, combination vs. I-131 or TRAIL. TRAIL, tumor necrosis factor-related apoptosis-inducing ligand; I-131, Iodine-131; FN, fibronectin; VN, vimentin; EN, E-cadherin.

Figure 4.

Additive treatment of TRAIL and I-131 inhibited tumor growth and promotes apoptosis of tumor cells. TRAIL-I-131 treatment inhibits tumor growth in (A) A549- and (B) H358-bearing mice compared with the TRAIL, I-131 and PBS groups. (C) TRAIL-I-131 treatment increased numbers of apoptotic cells in tumor tissues. (D) TRAIL-I-131 treatment upregulated caspase-9 expression in tumor tissues. All data are expressed as the mean and SD and analyzed using one-way ANOVA (with Tukey HSD test). *P<0.05; **P<0.01; I-131 or TRAIL vs. control, combination vs. I-131 or TRAIL. TRAIL, tumor necrosis factor-related apoptosis-inducing ligand; I-131, Iodine-131.