The biological function and clinical significance of STIL in osteosarcoma

Abstract

Background: SCL/TAL1 interrupting locus (STIL) is associated with the progression of several tumors; however, the biological role of STIL in osteosarcoma remains poorly understood.

Methods: In this study, the clinical significance of STIL in osteosarcoma was analyzed by gene chip data recorded in public databases. STIL expression was silenced in osteosarcoma cell lines to observe the effects on proliferation, apoptosis, invasion, and migration. Differentially expressed genes (DEGs) in the osteosarcoma chip were analyzed using The Limma package, and STIL co-expressed genes were obtained via the Pearson correlation coefficient. The potential molecular mechanism of STIL in osteosarcoma was further explored by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways.

Results: Osteosarcoma was associated with higher STIL expression compared to the control samples, and the standardized mean difference (SMD) was 1.52. STIL also had a good ability to distinguish osteosarcoma from non-osteosarcoma samples [area under the curve (AUC) = 0.96]. After silencing STIL, osteosarcoma cell proliferation decreased, apoptosis increased, and the migratory and invasion ability decreased. A total of 294 STIL differentially co-expressed genes were screened, and a bioinformatics analysis found that differentially co-expressed genes were primarily enriched in the cell signaling pathways. The protein-protein interaction (PPI) network indicated that the hub differentially co-expressed genes of STIL were CDK1, CCNB2, CDC20, CCNA2, BUB1, and AURKB.

Conclusions: STIL is associated with osteosarcoma proliferation and invasion, and may be promote the progression of osteosarcoma by regulating the expression of CDK1, CCNB2, CDC20, CCNA2, BUB1 and AURKB.

Keywords: Biomarkers; Invasion; Osteosarcoma; Proliferation; STIL.

Fig. 1

Flow diagram of the study

Fig. 2

STIL scatter plot based on osteosarcoma chips in the GEO and ArrayExpress databases. a E-MEXP-3628, b GSE11414, c GSE12865, d GSE14359, e GSE126209, f GSE33383, g GSE36001, h GSE39262, i GSE42352, j GSE68591, k GSE87625, l GSE99671, and m GSE19276. STIL, SCL/TAL1 interrupting locus. GEO Gene Expression Omnibus

Fig. 3

Evaluation of the level of STIL expression. a The level of STIL expression in osteosarcoma expressed as a forest plot based on a random effects model. b Sensitivity analysis of STIL expression in osteosarcoma. c Egger’s test to detect publication bias

Fig. 4

The ability of STIL to differentiate between osteosarcoma tissue and normal tissue. a SROC curve of STIL and b combined sensitivity and specificity of STIL. c The combined positive and negative likelihood ratio of STIL. d The combined diagnostic score and diagnostic odds ratio of STIL. SROC summarized receiver operating characteristic

Fig. 5

Effect of silencing STIL on the proliferation and apoptosis of osteosarcoma cells. a qRT-PCR detection of STIL expression in osteoblast and osteosarcoma cell lines. b WB detects the silencing efficiency of STIL. c CCK8 analysis showing that silencing STIL inhibited the proliferation of U-2 OS and HOS cell lines. d Apoptosis tests showed that silencing STIL promoted the apoptosis of the U-2 OS cell line. *p < 0.05; **p < 0.01 vs. hFOB1.19 or si-NC

Fig. 6

The effect of silencing STIL on the migration and invasion of osteosarcoma cells. a Transwell migration experiment showing that silencing STIL inhibits the migratory ability of osteosarcoma cell lines. b Transwell invasion experiment demonstrating the ability of silencing STIL to inhibit the invasion of osteosarcoma cell lines. *p < 0.05; **p < 0.01

Fig. 7

Survival analysis of STIL and differentially co-expressed genes. a Survival analysis of STIL based on the GSE21257 chip. b Venn diagram showing the STIL differentially co-expressed genes in osteosarcoma in the GEO and ArrayExpress databases. GEO Gene Expression Omnibus

Fig. 8

GO and KEGG analysis of 294 STIL differentially co-expressed genes. a Bubble chart of the first 10 Biological processes. b Bubble chart of the first 10 cellular components. c Bubble chart of the first 10 molecular functions. d The first 10 KEGG pathways. GO Gene Ontology, KEGG Kyoto Encyclopedia of Genes and Genomes

Fig. 9

PPI analysis of the STIL differentially co-expressed genes in osteosarcoma. Six Hub genes were selected in the PPI network of STIL differentially co-expressed genes. PPI protein-protein interaction

Fig. 10

Evaluation of levels of Hub gene expression in the GEO and ArrayExpress databases. a CDK1, b CCNB2, c CDC20, d CCNA2, e BUB1, and f AURKB. GEO Gene Expression Omnibus, GEO Gene Expression Omnibus

Fig. 11

SROC curve based on Hub gene expression in the GEO and ArrayExpress databases. a CDK1, b CCNB2, c CDC20, d CCNA2, e BUB1, and f AURKB. GEO Gene Expression Omnibus, SROC summarized receiver operating characteristic