We recently demonstrated that heat shock protein 90 (HSP90) is involved in the regulation of runt-related transcription factor 2 via the AKT/GSK-3β/β-catenin signaling pathway in OS.
Using next-generation RNA-sequencing, protein-based assays, as well as the loss- and gain-of-function approaches in selected osteosarcoma cell lines, we show that osteopontin messenger RNA levels closely correlate with RUNX2 expression and that RUNX2 controls the levels of secreted osteopontin.
NNT-As1 functions as a cancer-promoting lncRNA by downregulating miR-320a, thus increasing the protein expression level of beta-catenin, RUNX2 and IGF-1R as well as activation of Akt in osteosarcoma.
<b>Materials and methods:</b> The levels of 3,4-dihydroxyphenylacetic acid, norepinephrine, serotonin, and 5-hydroxyindoleacetic acid in cancer tissue and in adjacent and non-oncological bone tissue were analysed by high-performance liquid chromatography, and the gene expression of catecholamine receptors and of dopamine β-hydroxylase, monoaminoxidase, ki67, and Runx2 in the osteosarcoma tissue, tissue adjacent to the tumour, non-oncological bone, and human brain tissue was analysed by RT-PCR.
Intriguingly, runt-related transcription factor 2 (RUNX2) is expressed at higher level in numerous human cancers such as pancreatic cancer and osteosarcoma, indicating that, in addition to its pro-osteogenic role, RUNX2 has a pro-oncogenic potential.
Finally, we revealed that silybin inhibited OS cell viability by altering the protein levels of β-catenin and Runt-related transcription factor 2 (RUNX2) as determined by western blot and immunocytochemistry (ICC).
In conclusion, our data reveals that lncRNA SNHG20/miR-139/RUNX2 axis modulates the osteosarcoma tumorigenesis and apoptosis via mitochondrial apoptosis pathway, providing a novel insight for the pathophysiological process.
We analyzed protein levels and nuclear localization of β-catenin and RUNX2 in a panel of human osteosarcoma cell lines (SAOS, MG63, U2OS, HOS, G292, and 143B).
Vitamin D Impacts the Expression of Runx2 Target Genes and Modulates Inflammation, Oxidative Stress and Membrane Vesicle Biogenesis Gene Networks in 143B Osteosarcoma Cells.
Taken together, our results indicate that miR-302b functions as a tumour repressor in the invasion and migration of osteosarcoma by directly downregulating Runx2 expression and may be a potential therapeutic target for osteosarcoma.
Furthermore, the RUNX2 binding site, which encompasses positions ‑496 to ‑501 bp, was required to achieve maximal IPO8 promoter activity in Saos‑2 human osteosarcoma cells.
Overexpression of RUNX2 protected JQ1-sensitive OS cells from the effect of JQ1, and siRNA-mediated inhibition of RUNX2 sensitized the same cells to JQ1.
Based on this knowledge, we found more genes related to the pathogenesis of osteosarcoma and these genes could exert similar function as Runx2, a risk factor confirmed in osteosarcoma, this study may help better understand the genetic mechanism and provide new molecular markers and therapies for osteosarcoma.
A loss-of-function approach was used to investigate the effects of small hairpin RNA-mediated knockdown of YAP1 on the expression of RUNX2, CyclinD1, and matrix metalloproteinase-9 (MMP-9) as well as the proliferative activities and invasive potential in OS MG-63 cells (evaluated by MTT and Transwell assays, respectively).
Analysis of previously published OS aCGH data (GSE9654) and aCGH data from this study (GSE19180) identified significant deletion of WWOX in 30% (6/20) of OS samples, whilst significant increase in both RUNX2 and VEGFA gene copy numbers were detected in 55% (11/20) and 60% (12/20) of OS samples, respectively.
Thus, regulatory mechanisms controlling Runx2 expression in osteosarcoma cells must balance Runx2 protein levels to promote its putative oncogenic functions, while avoiding suppression of bone tumor growth.
With real-time polymerase chain reaction, the RUNX2 mRNA level was correlated with BMP-2 mRNA level, and both levels were significantly higher in three osteosarcoma cell lines than in three chondrosarcoma cell lines.