Association between SET expression and glioblastoma cell apoptosis and proliferation

Abstract

Glioblastoma multiforme (GBM) was one of the first cancer types systematically studied at a genomic and transcriptomic level due to its high incidence and aggressivity; however, the detailed mechanism remains unclear, even though it is known that numerous cytokines are involved in the occurrence and development of GBM. The present study aimed to determine whether the SET gene has a role in human glioblastoma carcinogenesis. A total of 32 samples, including 18 cases of glioma, 2 cases of meningioma and 12 normal brain tissue samples, were detected using the streptavidin-peroxidase method through immunohistochemistry. To reduce SET gene expression in U251 and U87MG cell lines, the RNA interference technique was used and transfection with small interfering (si)RNA of the SET gene was performed. Cell apoptosis was detected by flow cytometry, cell migration was examined by Transwell migration assay and cell proliferation was determined by Cell Counting Kit-8. SET, Bcl-2, Bax and caspase-3 mRNA and protein expression levels were detected by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Positive protein expression of SET was observed in the cell nucleus, with the expression level of SET significantly higher in glioma tissues compared with normal brain tissue (P=0.001). Elevated expression of SET was significantly associated with gender (P=0.002), tumors classified as World Health Organization grade II (P=0.031), III (P=0.003) or IV (P=0.001), and moderately (P=0.031) or poorly differentiated (P=0.001) tumors. Compared with the negative and non-treatment (blank) control cells, SET gene expression was significantly inhibited (P=0.006 and P<0.001), cell apoptosis was significantly increased (P=0.001 and P<0.001), cell proliferation was significantly inhibited (P=0.002 and P=0.015), and cell migration was significantly decreased (P=0.001 and P=0.001) in siRNA-transfected U87MG−SET and U251−SET cells, respectively. In addition, mRNA and protein expression levels of Bcl-2 were significantly inhibited in U87MG−SET and U251−SET cells, while mRNA and protein expression levels of Bax and caspase-3 were significantly increased, compared with the two control groups. Thus, the current data suggests that SET may regulate the proliferation and apoptosis of glioblastoma cells by upregulating Bcl-2, and downregulating Bax and caspase-3.

Interaction between C2ORF68 and HuR in human colorectal cancer

“…Immunohistochemistry (IHC) of the rectal cancer tissue microarray. IHC was performed as previously described (19). Clinicopathological parameters of the CRC patients are shown in Table I.…”

“…Cell proliferation assay. The cell proliferation assay was performed as previously described (19). Plates were read at an absorbance wavelength of 450 nm with the help of a microplate reader (Model 680; Bio-Rad Laboratories, Hercules, CA, USA).…”

“…Flow cytometry. Flow cytometry was performed as previously described (19). Then, the results were analyzed by flow cytometry (FACSAria II Cell Sorter; BD Biosciences, Franklin Lakes, NJ, USA).…”

“…Cell migration assay. Cell migration assay was performed as previously described (19). Migrated cells were quantified by counting the stained cells under a microscope (Model 680; Bio-Rad Laboratories) at x200 magnification.…”

“…qRT-PCR analysis. qRT-PCR analysis was performed as previously described (19). The sequences of forward and reverse primers are shown in Table II.…”