Small interfering RNA targeting paul-like kinase 1 gene silencing inhibits colon cancer invasion and proliferation in clinical, cellular and mouse studies

Abstract

Objective To investigate the clinical, cellular and mouse studies of small interfering RNA (siRNA) targeting silencing of paul-like kinase 1 (PLK1) on colon cancer invasion and proliferation. Methods Sixty-eight patients with colon cancer admitted to the Second Affiliated Hospital of Hainan Medical College from July 2013 to September 2018 were enrolled, including 40 males and 28 females. The average age was (47.5±6.2) years. Western blotting and real-time quantitative PCR (RT-qPCR) were used to detect PLK1 protein and mRNA levels, respectively. In vitro invasion assay (Transwell) and cell proliferation and toxicity (CCK-8) assays detect cell invasion and proliferation. A subcutaneous xenograft nude mouse colon cancer model was constructed for animal experiments. The F-test was used to compare the measurement data among groups, and the t-test was used for the comparison between the two groups. The rate was compared using the χ2 test. Correlation analysis was performed using the Spearman method. Results Compared with adjacent tissues (8.72±2.19), the mRNA level of PLK1 in colon cancer tissues (15.34±3.86) was significantly increased (t=12.593, P<0.05). The level of PLK1 was positively correlated with tumor invasion depth (r=0.368, P<0.05) and TNM stage (r=0.403, P<0.05). Compared with the siRNA negative control [invasion: (37.20±4.50)], the invasive ability of SW480 cells was significantly decreased after PLK1-siRNA-1 [invasion: (15.00±3.75)] and PLK1-siRNA-2 [invasion: (14.60±3.40)] treatments (t=5.073, t=4.985, P<0.05). At 24 h, 48 h, and 72 h, compared to the siRNA negative control [absorbance (A) values: 0.53±0.12, 0.73±0.16, 0.86±0.18], the proliferation of PLK1-siRNA-1 (0.32±0.10, 0.40±0.08, 0.53±0.10) and PLK1-siRNA-2 (0.34±0.08, 0.41±0.09, 0.54±0.11) decreased significantly (t=4.167, t=4.990, t=4.833, t=4.001, t=4.708, t=4.665, P<0.05). Compared with the siRNA negative control [tumor volume: (849.12±65.37) mm3; number of nodules: (9.35±2.15)], the mean tumor volume and the number of tumor nodules in nude mice treated with PLK1-siRNA-1 [tumor volume: (135.06±9.11) mm3; number of nodules: 1.46±0.20] and PLK1-siRNA-2 [tumor volume: (127.45±8.86) mm3; number of nodules: (1.30±0.15)] were significantly lower (t=19.168, t=7.004, t=20.365, t=7.659, P<0.05). Conclusion Targeted silencing of PLK1 can inhibit the invasion and proliferation of colon cancer, and provide a theoretical basis for the targeted prevention and treatment of colon cancer. Key words: Colon cancer; Paul-like kinase 1; Invasion; Proliferation