Circular RNA circBLNK promotes osteosarcoma progression and inhibits ferroptosis in osteosarcoma cells by sponging miR­188­3p and regulating GPX4 expression.

As a newly identified circular RNA (circRNA), the role of circBLNK in cancer progression has not been probed. The objective of the present study was to functionally dissect the role of circBLNK in osteosarcoma (OS) tumorigenesis and progression. With regards of the experimental procedure, the levels of mRNAs and proteins were assessed using reverse transcription­quantitative PCR and western blot analysis, respectively. The subcellular location of circBLNK in OS cells was determined by cell cytosolic/nuclear fractionation assay. Cell ferroptosis ability was assessed through MTT assay. Cell proliferative abilities were assessed by clonogenic and Cell Counting Kit­8 assays, and cell apoptosis was measured using flow cytometry. The relationships among circBLNK, miR­188­3p, and glutathione peroxidase 4 (GPX4) were validated by luciferase reporter and RNA pull­down assays, as well as RNA immunoprecipitation. The stability of circBLNK and linear BLNK was confirmed using RNase R treatment assay. The association between circBLNK expression and overall survival rate was assessed by Kaplan­Meier plot. The correlation between the expression levels of circBLNK, miR­188­3p, and GPX4 in OS tissues was assessed by Pearson's χ2 test. The results revealed that CircBLNK and GPX4 were significantly upregulated in OS tissues, which predicted the poor prognosis. CircBLNK knockdown led to suppressed cell proliferation and enhanced cell apoptosis, an effect that could be reversed by the inhibition of miR­188­3p. In an in vivo circBLNK deficiency model, tumor growth was observed to be markedly suppressed. Moreover, circBLNK deficiency elevated levels of intracellular free iron (Fe2+), malondialdehyde, lipid reactive oxygen species and mitochondrial superoxide, while diminishing mitochondrial membrane potential in Erastin­treated OS cells, which were eliminated by overexpressing GPX4. Furthermore, mechanistic investigations revealed that circBLNK sponged miR­188­3p to regulate the expression of GPX4, thereby affecting OS progression. In conclusion, the present study delineated a new regulatory axis involving circBLNK/miR­188­3p/GPX4 in OS progression, adding to the growing evidence that circRNAs are critical gene regulators in cancer progression.

Zbtb7b suppresses aseptic inflammation by regulating m6A modification of IL6 mRNA.

Radiotherapy is a crucial approach for treating tumors. However, radiation-induced aseptic inflammation is a common complication. Radiation pneumonitis is the acute manifestation of radiation-induced lung disease, and interleukin 6 (IL-6) is a major proinflammatory cytokine involved in radiation-induced lung injury. Here we found that silencing Zinc finger and BTB domain-containing protein 7B (Zbtb7b) resulted in higher radiation-induced IL-6 production in THP1 cells and BEAS-2B lung bronchial epithelial cells. Mechanistically, Zbtb7b recruited RNA demethylase ALKBH5 to IL6 mRNA. Subsequentially, it demethylated N6-methyladenosine (m6A) modification of IL6 mRNA and inhibited its nuclear export. Thus, Zbtb2b epigenetically suppresses irradiation-induced IL-6 production in the lungs via inhibiting the m6A modification and nucleocytoplasmic transport of IL6 mRNA, serving as a new potential predictive marker and therapeutic target in radiation pneumonitis treatment.

FGF5 promotes osteosarcoma cells proliferation via activating MAPK signaling pathway.

Objective: This study aimed to investigate the role of fibroblast growth factor-5 (FGF5) in osteosarcoma (OS) and explore the potential mechanisms. Methods: OS gene expression data was downloaded from the Gene Expression Omnibus (GEO; GSE12865) and analyzed by R software. OS tissues and cell lines were collected. The expression level of FGF5 in tumor tissues and cell lines was detected using qRT-PCR. Knockout of FGF5 was performed using CRISPR/Cas9 system. The effects of FGF5 knockout on OS cell proliferation and tumor growth were determined through cell counting kit-8 assay and xenograft nude mice, respectively. Additionally, recombinant FGF5 (rFGF5) was added into OS cell and the effects of rFGF5 on the proliferation and apoptosis of OS cell lines were assayed. Furthermore, the protein expression levels of mitogen-activated protein kinase (MAPK) signaling pathway were detected through Western blot. Results: FGF5 was significantly upregulated in OS tissues and cells, and closely associated with poor differentiation, larger tumor size, lymph node metastasis, and advanced TNM stage. FGF5 knockout could inhibit proliferation of OS cells and tumor growth in nude mouse model. Addition of exogenous rFGF5 promoted OS cell proliferation while inhibited OS cell apoptosis. The expression levels of MAPK signaling pathway proteins in FGF5 knockout group were significantly lower than that in control when there was no rFGF5. Additionally, their expression level in rFGF5 addition group was higher than that in without rFGF5 group. Conclusion: We demonstrated for the first time that FGF5 was overexpressed in OS cell lines and clinical tissue samples and promotes OS cell proliferation by activating MAPK signaling pathway, which indicated that FGF5 was a potential therapeutic target for OS.

Ergostane steroids from the ethanol extract of Dysoxylum mollissimum.

Three new ergostane steroids, 7α-acetoxyl-ergosta-5,24(28)-diene-3ß,4ß,20S-triol (1), 7α-acetoxyl-ergosta-5,24(28)-diene-3ß,4ß-diol (2), and 7α-acetoxyl-ergosta-5,24(28)-3ß-ol (3) were isolated from the ethanol extract of stem bark of Dysoxylum mollissimum BI. Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. All the isolated steroids were in vitro evaluated for their anti-inflammatory activity against COX-1 and COX-2. As a result, steroids 1-3 exhibited modest selective inhibition for COX-1 (>60%).

Plasma Hemopexin ameliorates murine spinal cord injury by switching microglia from the M1 state to the M2 state.

Spinal cord injury (SCI) is a devastating type of central nervous system (CNS) trauma with limited therapeutic treatments. The polarization of microglia into the M1 or M2 state has been documented to play important roles in the pathogenesis of SCI, although the complete repertoire of underlying factors has not been identified. Interestingly, the time point at which hematomyelia (intramedullary spinal cord hemorrhage) is alleviated coincides with a decrease in the number of M2 microglia. Here the function of Hemopexin (Hpx), a hematogenous glycoprotein, was examined in the crush model of SCI. Hpx levels were elevated at the lesion site during hematomyelia and were synchronously correlated with the level of the M2 marker Arginase-1 (Arg-1). Ablation of Hpx in vivo affected the polarization state of lipopolysaccharide (LPS)-stimulated microglia, as mirrored by a lower percentage of M2 microglia and a higher percentage of M1 microglia in the lesion site, which delayed the recovery and exacerbated the behavioral dysfunction after SCI. However, Hpx induced a rapid switch from the M1 to M2 phenotype in LPS-stimulated primary cultured microglia in a heme scavenging-independent manner. The supernant of Hpx-treated microglia ameliorated neuronal degeneration, alleviated demyelination, and promoted oligodendrocyte precursor cell (OPC) maturation. This modulatory effect of Hpx on microglia polarization was at least partially mediated by the LRP-1 receptor. Based on these results, Hpx is considered a novel modulator of the polarization of microglia during the pathogenesis of SCI and may play a crucial role in the recovery from SCI.

Monoterpenoid indole alkaloids from Alstonia mairei and their cytotoxicity.

Phytochemical investigation on the 70% ethanol extract of the leaves of Alstonia mairei resulted in the isolation of three new monoterpenoid indole alkaloids, alstomairines A-C (1-3), along with one known compound, alpneumine A (4). Structural elucidation of all the compounds was accomplished by spectral methods such as 1D and 2D NMR, IR, UV, and HRESIMS. The isolated compounds were tested in vitro for cytotoxic activities against four osteosarcoma cell lines. Consequently, alkaloids 2 and 3 exhibited cytotoxic activities for all tested tumor cell lines with IC50 values from 9.2 to 13.0 µM.

Insulin-like growth factor-binding protein 7 is up-regulated during EAE and inhibits the differentiation of oligodendrocyte precursor cells.

Oligodendrocyte precursor cells (OPCs) differentiation failure is one of the leading causes for remyelination defects in the demyelinating lesions of multiple sclerosis (MS). In this study, we explored the roles of insulin-like growth factor-binding proteins 7 (IGFBP-7) on OPCs differentiation during experimental autoimmune encephalomyelitis (EAE). We first investigated the expression pattern of IGFBP-7 by real-time PCR and immunofluorescence staining. It showed that IGFBP-7 was expressed in astrocytes (ACs), oligodendrocytes (OLs) and neurons both in vitro and in vivo. The mRNA and protein level of IGFBP-7 was also increased in the spinal cord from mice at the peak of EAE disease. Next we found that IGFBP-7 acted as a negatively regulator of the OPCs differentiation. Together, these data suggest that IGFBP-7 was up regulated during EAE and inhibit the transition from OPCs to mature OLs, implying its use as a potential therapeutic target for the treatment of inflammatory demyelinating diseases.