Effect of CCL2 siRNA on proliferation and apoptosis in the U251 human glioma cell line.

Glioma is one of the most common types of tumor of the central nervous system. Increased expression of C‑C motif chemokine 2 (CCL2) has previously been observed in various types of cancer. The effect of CCL2 small interfering (si)RNA on the proliferation, angiogenesis and apoptosis of the glioma cell line U251 was investigated in the present study. Data on CCL2 expression in glioma and normal tissues were obtained from The Cancer Genome Atlas. A total of 30 patients with glioma were enrolled in the present study. Cell proliferation was measured using a Cell Counting kit‑8 assay, while cellular apoptosis and cell cycle distribution were examined using flow cytometric analysis. The reverse transcription‑quantitative polymerase chain reaction and western blot analysis were used to measure the expression levels of biological pathway‑associated proteins caspase‑3, caspase‑7, tumor necrosis factor receptor superfamily member 10C (TNFRSF10C), growth regulated α protein (CXCL1), C‑X‑C motif chemokine 2 (CXCL2), C‑X‑C chemokine receptor type 2 (CXCR2), vascular endothelial growth factor (VEGF)A, VEGFB and VEGF. In addition, the mechanism of cellular apoptosis was analyzed by examining the phosphorylation of extracellular signal‑related kinase (ERK)1/2 and p38 mitogen‑activated protein kinase (p38) in cells treated with the C‑C chemokine receptor type 2 inhibitor RS‑102895. CCL2 was observed to be expressed in the glioma cell line U251 and was inhibited by CCL2 siRNA. Cells transfected with CCL2 siRNA exhibited inhibited cell proliferation, cell cycle arrest and increased cellular apoptosis. The expression levels of the apoptosis‑associated proteins caspase‑3, caspase‑7 and TNFRSF10C were observed to be downregulated, in addition to those of the angiogenesis‑associated proteins CXCL1, CXCL2, CXCR2, VEGFA, VEGFB and VEGF. The decrease in the rate of phosphorylation of ERK1/2 and p38 demonstrated the involvement of the mitogen‑activated protein kinase/ERK pathway in apoptosis. In conclusion, CCL2 siRNA exhibited effective inhibition of cell proliferation and angiogenesis in the glioma cell line U251, which may provide a theoretical basis for the use of CCL2 in in vivo research and clinical treatment as a novel anticancer agent.