Expression of NOD-like receptor family pyrin domain-containing protein 3 in colorectal cancer and its role in cell proliferation and migration

Abstract

Objective To investigate the expression of NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) and its role in biological behaviors of colorectal cancer (CRC) cells. Methods The expression of NLRP3 was determined by immunohistochemistry in CRC samples and normal colon mucosal tissues. Kaplan-Meier method and Log-rank test were used to estimate survival rate. Cox proportional hazards model was used to calculate multivariate hazard ratios for the study variables. The real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) and Western blotting were used to determine the mRNA and protein expression of NLRP3 respectively. Methyl thiazol tetrazolium (MTT) and Transwell invasion assay were used to determine the effect of NLRP3 on CRC cells. Results The NLRP3 expression was down-regulated in most of the CRC cells, with 46 cases low expression and 10 cases of high expression. Low NLRP3 expression was correlated with depth of invasion (P=0.024), lymph node metastasis (P=0.009), liver metastasis (P=0.038), and TNM stages (P=0.024). Patients with low NLRP3 expression had shorter overall survival than those with high expression (P=0.010). Low NLRP3 expression was an independent prognostic factor for CRC (P=0.047). NLRP3 over-expression could significant inhibit CRC cell proliferation and migration. The A values of SW480 in control group and p-NLRP group at 72 h were 0.63±0.06 and 0.91±0.03, respectively (P=0.010), and at 96 h 1.07±0.05 and 1.48±0.05, respectively (P=0.003). The optical density value (A) values of HCT116 in control group and p-NLRP group at 72nd h were 0.80±0.05 and 1.20±0.08, respectively (P=0.005), and at 96 h 1.02±0.08 and 1.64±0.05, respectively (P=0.003). The number of SW480 cells penetrating the membrane in control group and p-NLRP group was 104±8 and 30±4, respectively (P=0.008). The number of HCT116 cells penetrating the membrane in control group and p-NLRP group was 123±6 and 36±3, respectively (P=0.022). Conclusion These results indicate that NLRP3 is a novel prognostic marker in CRC patients, and plays a critical role in CRC progression. Key words: Colorectal cancer; NOD-like receptor family pyrin domain-containing protein 3; Proliferation; Migration