Fibroblast growth factor receptor 1 promotes MG63 cell proliferation and is associated with increased expression of cyclin-dependent kinase 1 in osteosarcoma

Abstract

Osteosarcoma is the most common type of malignant bone tumor in adolescents and young adults. However, current understanding of osteosarcomagenesis remains limited. In the present study, the role of fibroblast growth factor receptor 1 (FGFR1) in human osteosarcoma cell proliferation was investigated, and the possible pathways that contribute to FGFR1‑mediated osteosarcoma cell proliferation were examined using microarray analysis. The expression of FGFR1 in osteosarcoma tissues was assessed by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. The results demonstrated that FGFR1 was markedly increased in osteosarcoma tissues, and that the overexpression of FGFR1 in MG63 cells significantly promoted cell proliferation, as observed using the cell viability assay. In addition, FGFR1‑mediated cell proliferation was closely associated with cell cycle re‑distribution, as determined by microarray analysis. Western blotting identified that the expression of cyclin-dependent kinase 1 (CDK1) was correspondingly increased in response to the overexpression of FGFR1. These results indicated that FGFR1 contributes to cell proliferation in osteosarcoma MG63 cells, and FGFR1 mediated cell proliferation may be attributed to the regulation of the cell cycle regulator, CDK1. These findings provide evidence to support the potential use of molecule target therapy against FGFR1 as a promising strategy in osteosarcoma treatment and prevention.

Figure 1

Expression of FGFR1 is high in osteosarcoma tissues. (A) IHC analysis of osteosarcoma and paired normal bone tissues with the FGFR1 antibody. The protein level of FGFR1 was significantly elevated in the osteosarcoma tissues (magnification, ×200). (B) Determination of the mRNA level of FGFR1 in osteosarcoma and paired normal tissues. The changes in the mRNA expression levels were consistent with the results of the IHC analysis. Data are expressed as the mean ± standard deviation. FGFR1, fibroblast growth factor receptor 1; ICH, immunohistochemisty.

Figure 2

FGFR1 affects the cell cycle in osteosarcoma. (A) Kyoto Encyclopedia of Genes and Genomes analysis revealed that the (a) cell cycle was significantly affected in osteosarcoma (P=0.003), whereas no significant change was observed in the (b) bone remodeling process (P=0.369). (B) Heatmap analysis revealed increases in the experession of a broad spectrum of genes associated with the cell cycle, whereas the expression of other genes decreased. (C and D) Multiple cell cycle-associated genes were upregulated, while other genes were downregulated. FGFR1, fibroblast growth factor receptor 1.

Figure 3

CDK1 is upregulated by FGFR1 in MG63 osteosarcoma cells. (A) Transfection efficiency was verified using a fluorescence microscope (magnification, ×200). (B) Reverse transcription-quantitative polymerase chain reaction analysis of the mRNA levels of CDK1 and CDK2 in FGFR1-overexpressed MG63 cells. The mRNA expression of CDK1 was upregulated by FGFR1 overexpression (^*P<0.05). Data are expressed as the mean ± standard deviation. (C) Western blotting revealed that the protein expression of CDK1 increased following transfection of the MG63 cells with the FLAG-FGFR1 plasmid. CDK, cyclin-dependent kinase; FGFR1, fibroblast growth factor receptor 1.

Figure 4

Overexpression of FGFR1 promotes MG63 cell proliferation. The MG63 cells were transfected with the FGFR1 expression plasmid. At 48 h post-transfection, the cells from FGFR1-overexpression group and control group were examined using a cell viability assay. The cells in the FGFR1-overexpressed group exhibited increased proliferative activity from day 2. On day 4, the number of cells in the FGFR1-overexpressed group were ~1.7-fold higher than those in the control group. FGFR1, fibroblast growth factor receptor 1; OD, optical density.