Clinicopathological correlation of insulin-like growth factor binding protein 3 and their death receptor in patients with gastric cancer

Abstract

Background and purpose: The insulin-like growth factor binding protein 3 (IGFBP-3) and its novel death receptor (IGFBP-3R) have been exhibited to have tumor suppressor effects. Despite their prognostic value in some cancers, they have not been elucidated in gastric cancer.

Experimental approach: We collected 68 samples from patients with gastric cancer. IGFBP-3 and IGFBP-3R expression levels were evaluated with quantitative real-time polymerase chain reaction (RT-PCR) and western blotting in patients. The relationship between prognostic factors and IGFBP-3/IGFBP-3R expression was also evaluated.

Findings/results: Our results showed that IGFBP-3 and IGFBP-3R expression was reduced significantly in tumor tissues. We found that there was an association between the reduction of IGFBP-3 with lymph node metastasis and tumor-node-metastasis (TNM) staging. Besides, IGFBP-3R expression was associated with tumor size, lymph node metastasis, differentiation, and TNM classification. Interestingly, we presented that the downregulation of IGFBP-3R was stage-dependent. In survival analysis, our findings showed that low levels of IGFBP-3R mRNA expression exhibited a close correlation with survival rate.

Conclusion and implications: The findings of this study showed that the expression levels of IGFBP-3 and IGFBP-3R are valuable prognostic factors. Despite the potential of IGFBP-3, IGFBP-3R plays a significant role as a prognostic factor in gastric cancer. However, these findings need to be developed and confirmed by further studies.

Keywords: Gastric cancer; IGFBP-3; IGFBP-3R; Prognostic factor; TNM classification..

Fig. 1.

Down-regulation of the mRNA expression level of IGFBP-3 and tumor-node-metastasis stage analysis in gastric cancer. Relative expression was performed with quantitative real-time polymerase chain reaction and calculated with the 2^-ΔΔCt method, normalized all curve thresholds using GAPDH as an internal control. (A) Comparison of relative expression of IGFBP-3 in cancer tissue and normal adjacent tissues; (B) analyzing IGFBP-3 fold-changes relative expression in gastric cancer stages. Data are expressed as mean ± SEM. ^***P < 0.001 represents significant differences in comparison with the control group. IGFBP, Insulin-like growth factor binding protein; GAPDH glyceraldehyde 3-phosphate dehydrogenase.

Fig. 2.

Protein expression of IGFBP-3 determined with western blotting. All bands were normalized with β-actin as an internal control, and the intensity of all bands was calculated with Image J software. (A) a representative image of IGFBP-3 bands in tumoral cancer and normal adjacent tissue; (B) ratio protein expression in gastric cancer tissue in comparison with normal adjacent tissue; and (C) analysis of protein fold change according to tumor-node-metastasis stage classification. Data are expressed as mean ± SEM. ^**P < 0.01 and ^***P < 0.001 represent significant differences in comparison with the control group; ^###P < 0.001 indicates differences between a column and its previous one. T, Tumoral cancer; N, normal tissue; IGFBP, insulin-like growth factor binding protein.

Fig. 3.

Analyzing of IGFBP-3R mRNA expression fold change in gastric cancer. (A) Comparison of IGFBP-3R relative expression gastric cancer tissue in comparison with normal adjacent tissue; (B) analyzing IGFBP-3R mRNA fold change in different stages. Data are expressed as mean ± SEM. ^*P < 0.05 and ^***P < 0.001 represent significant differences in comparison with the control group; ^##P < 0.01 and ^###P < 0.001 indicate differences between a column and its previous one. IGFBP-3R, Insulin-like growth factor binding protein 3 receptor.

Fig. 4.

Analyzing of IGFBP-3R protein expression in gastric cancer and stages by western blotting. All bands normalized with β-actin. (A) The bands indicate the protein expression of IGFBP-3R and β-actin in the tumor and normal tissues; (B) IGFBP-3R protein expression reduced in all patient samples; (C) analysis of IGFBP-3R pattern according to tumor-node-metastasis stage classification. ^***P < 0.001 represents significant differences in comparison with the control group; ^###P < 0.001 indicates differences between a column and its previous one. T, Tumoral cancer; N, normal tissue; IGFBP-3R, insulin-like growth factor binding protein 3 receptor.

Fig. 5.

Correlation of IGFBP-3 and IGFBP-3R expression with cumulative survival patient for 68 gastric cancer patients. Favored or non-favored patient with different expressions (low and high expressions based on mean) was calculated and analyzed with the log-rank test and presented with a Kaplan-Meier plot. (A) The low or high expression level of IGFBP-3R correlates with a poorer overall; (B) relative expression of IGFBP-3 has no significant correlation with the overall survival of a patient with gastric cancer. IGFBP-3, Insulin-like growth factor binding protein 3; IGFBP-3R, insulin-like growth factor binding protein 3 receptor.