Circular RNA 0086996 regulates growth and migration of osteosarcoma cells via miR-125b-5p

MiR-125b-5p/STAT3 Axis Regulates Drug Resistance in Osteosarcoma Cells by Acting on ABC Transporters

Background

The poor prognosis of the highly malignant tumor osteosarcoma stems from its drug resistance and therefore exploring its resistance mechanisms will help us identify more effective treatment options. However, the effects of miR-125b-5p on drug resistance in osteosarcoma cells are still unclear.

Methods

To study the effects of miR-125b-5p on drug resistance in osteosarcoma cells. Osteosarcoma-resistant miR-125b-5p was obtained from the databases GeneCards and g:Profiler. CCK8, western blot, and transwell were applied for the detection of the miR-125b-5p effects on proliferation, migration, invasion, apoptosis, and drug resistance in osteosarcoma. Bioinformatics is aimed at demonstrating the targeting factor miR-125b-5p, performing protein interaction enrichment analysis by Metascape, and finally validating by binding sites.

Results

Upregulation of miR-125b-5p restrains proliferation, migration, and invasion of osteosarcoma and promotes apoptosis. In addition, miR-125b-5p can restore drug sensitivity in drug-resistant osteosarcoma. miR-125-5p restrains the signal transducer and inhibits the transcription 3 (STAT3) expression activator via targeting its 3'-UTR. STAT3 affects drug-resistant osteosarcoma to regulate the ABC transporter.

Conclusion

miR-125b-5p/STAT3 axis mediates the drug resistance of osteosarcoma by acting on ABC transporter.

Hypoxic glioma cell-secreted exosomal circ101491 promotes the progression of glioma by regulating miR-125b-5p/EDN1

Hypoxia and exosomes play important roles in the occurrence and development of glioma. While circRNAs are involved in biological processes of various tumors, the mechanism underlying exosome-dependent regulatory effects of circRNAs on the progression of glioma under hypoxia is unclear. Results suggested that circ101491 was overexpressed in tumor tissues and plasma exosomes of glioma patients, while the overexpression of circ101491 was closely related to the differentiation degree and TNM staging of the patients. Moreover, circ101491 overexpression promoted viability, invasion and migration of glioma cells both in vivo and in vitro; the above regulatory effects can be reversed by inhibition of circ101491 expression. Mechanistic studies revealed that circ101491 upregulated EDN1 expression through sponging miR-125b-5p, thus facilitating glioma progression. In summary, hypoxia could promote circ101491 overexpression in glioma cell-derived exosomes, and circ101491/miR-125b-5p/EDN1 regulatory axis might be implicated in the malignant progression of glioma.

Circ_0051079 functions as an oncogenic regulator in osteosarcoma by leading to MAFB expression upregulation by competitively interacting with miR-1286

Background

Circular RNAs are involved in various cellular processes of bone diseases by acting as miRNA sponges to regulate gene expression levels, including osteosarcoma (OS). This research concentrated on the molecular mechanism of circ_0051079 in OS progression.

Methods

Reverse transcription-quantitative polymerase chain reaction assay was used for expression detection of circ_0051079, microRNA-1286 (miR-1286), and musculoaponeurotic fibrosarcoma oncogene homolog B (MAFB). Cell Counting Kit-8 assay and Edu assay were used for cell proliferation analysis. Cell apoptosis was evaluated using flow cytometry. Western blot was performed to measure protein levels. Migration and invasion were assessed via transwell assay. Interaction of circ_0051079/miR-1286 or miR-1286/MAFB was explored through a dual-luciferase reporter assay. In vivo research was carried out via tumor xenograft assay and immunohistochemistry staining.

Results

Circ_0051079 expression was upregulated in OS. Downregulation of circ_0051079 reduced OS cell proliferation, migration, invasion, and accelerated apoptosis. Circ_0051079 interacted with miR-1286, and the tumor-inhibitory function of si-circ_0051079 was abolished by miR-1286 inhibition in OS cells. MAFB served as a target for miR-1286. OS cell progression was suppressed by miR-1286 overexpression via downregulating MAFB. Circ_0051079/miR-1286 resulted in expression change of MAFB in OS cells. Silencing circ_0051079 inhibited tumor growth in vivo via regulating the miR-1286/MAFB axis.

Conclusion

The collective results elucidated that circ_0051079 contributed to OS progression via miR-1286-mediated upregulation of MAFB, confirming the interaction of circ_0051079/miR-1286/MAFB axis in OS.

Circular RNA circMRPS35 regulates progression and autophagy in osteosarcoma cells by recruiting KAT6B to govern FOXO3

Osteosarcoma serves as frequently occurred bone malignancy that displays low survival rate and high incidence of metastasis. Circular RNAs (circRNAs) have been reported as the crucial molecules in osteosarcoma development. However, the effect of circRNA circMRPS35 on osteosarcoma remains unclear. Here, we aimed to explore the function of circMRPS35 in the regulation of autophagy and progression of osteosarcoma. The colony formation numbers and Edu-positive osteosarcoma cells were repressed by the overexpression of circMRPS35. Meanwhile, the overexpression of circMRPS35 increased the apoptosis rate of osteosarcoma cells. The expression levels of autophagy markers, including LC3 and Beclin1, were enhanced by the overexpression of circMRPS35 in osteosarcoma cells. Mechanically, the depletion of circMRPS35 reduced the enrichment of histone H3 lysine 23 acetylation (H3K23ac) on forkhead box O3 (FOXO3) promoter in osteosarcoma cells. The interaction of circMRPS35 and KAT6B was identified. The knockdown of KAT6B reduced the enrichment of H3K23ac on FOXO3 promoter in osteosarcoma cells. The depletion of circMRPS35 repressed the expression of FOXO3 in the MG63 and MNNG/HOS cells, whereas the overexpression of KAT6B reversed the effect. Significantly, KAT6B promotes apoptosis and autophagy of osteosarcoma cells. The overexpression of circMRPS35 induced the apoptosis and autophagy of osteosarcoma cells, in which the depletion of KAT6B or FOXO3 reversed the effect. The overexpression of circMRPS35 inhibited the tumor growth in vivo , whereas the depletion of KAT6B could reverse the effect in the mice. Therefore, we concluded that circRNA circMRPS35 repressed progression and induced autophagy of osteosarcoma cells.