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AIM: This research aims to investigate the expression profile of circRNA in osteosarcoma and to identify the underlying pathogenesis core genes of osteosarcoma.Methods: Illumina HiSeq was used to screen differentially expressed circRNAs between the tumour tissues and paracancerous tissues of three osteosarcoma patients. Bioinformatics analysis was used to analyse their potential functions. Five differentially expressed circRNAs were selected to detect the relative expression level in tumour and paracancerous tissues of ten osteosarcoma patients by real-time PCR. The databases such as DisGeNET and miRWalk were used to collect related genes or miRNAs. RESULTS: A total of 259 differentially expressed circRNAs were evaluated in patients with osteosarcoma, of which 132 were up-regulated and 127 were down-regulated. Compared with that in paracancerous tissues, circ_32279 and circ_24831 were significantly down-regulated while circ_2137 and circ_20403 were significantly up-regulated in osteosarcoma tissues. The differential expression of circRNA is closely linked to biological processes and molecular functions. The difference in circRNA was mainly linked to the 'phosphatidylinositol signalling system' signal pathway and the 'inositol phosphate metabolism' signal pathway. CONCLUSION: The present study identified a profile of abnormal regulation of circRNA in osteosarcoma. Bioinformatics analysis indicates that the deregulated circRNAs may be related to the occurrence and development of osteosarcoma.

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BACKGROUND: This study aims to explore the effect of knockdown of the ribosomal protein L34 (RPL34) on osteosarcoma cell proliferation through EIF3/FAU. METHODS: The mRNA expression levels of RPL34, EIF3A, EIF3F, EIF3G, UBA52, UBC, and FAU were quantified using quantitative real-time PCR (qRT-PCR) in two human cell lines: the hFOB1.19 osteoblast cell line and the Saos-2 osteosarcoma cell line. The qRT-PCR analysis was performed to confirm the shRNA-mediated depletion of RPL34, and a western blot analysis was done to confirm the knockdown of protein levels. qRT-PCR was also used to examine the effects of RPL34 knockdown on the above genes. RESULTS: The mRNA expression levels of RPL34, EIF3A, EIF3G, UBA52, UBC, and FAU were increased in the Saos-2 cells relative to the hFOB1.19 osteoblast cells. EIF3F expression was decreased in Saos-2 cells relative to hFOB1.19 cells. Knockdown of RPL34 mRNA significantly suppressed EIF3A and EIF3F expression and significantly up-regulated FAU expression in the Saos-2 cell line, but there were no remarkable differences in the relative expression in the EIF3G, UBA52, and UBC genes. CONCLUSIONS: Knockdown of RPL34 suppresses osteosarcoma cells proliferation probably through EIF3A, EIF3F, and FAU.

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BACKGROUND Glutamate metabotropic receptor 4 (GRM4) has been correlated with the pathogenesis of osteosarcoma. The objective of this study was to explore the underlying molecular mechanism of GRM4 in osteosarcoma. MATERIAL AND METHODS The expression levels of GRM4 in four human osteosarcoma cell lines and hFOB1.19 cells were examined by real-time quantitative PCR (RT-qPCR). The U2OS cells of the highest GRM4 expression were transfected with lentivirus-mediated small interfering RNA (siRNA). The differentially expressed genes (DEGs) after GRM4 gene silencing were screened through RNA sequencing, and analyzed by bioinformatics. Additionally, the transcription factors (TFs) targeting GRM4 were predicted and the downstream protein-protein interaction (PPI) network was constructed using the bioinformatics approach. RESULTS A total of 51 significant DEGs were obtained, including 14 upregulated and 37 downregulated DEGs. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the DEGs indicated that four significant enrichment pathways were obtained. A total of six TFs that could be involved in the transcriptional regulation of GRM4 were detected. The results showed that 182 genes in the PPI network were significantly enriched in 14 pathways. The chemokines and chemokine receptors were found to be significantly enriched in three pathways. CONCLUSIONS The DEGs in the four significant enrichment pathways might participate in the development and progression of osteosarcoma through GRM4. The results revealed that EGR1 and CTCF are probably involved in the transcriptional regulation of GRM4, which participates in the progress of osteosarcoma by interacting with chemokines and their receptors.

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Osteosarcoma has devastating health implications on children and adolescents. However, due to its low incidence and high tumor heterogeneity, it is hard to achieve any further improvements in therapy and overall survival. Ribosomal protein L34 (RPL34) has been increasingly recognized to promote the proliferation of malignant cells, but its role in osteosarcoma has not been investigated. In this study, real-time quantitative PCR (RT-qPCR) and immunohistochemistry revealed that RPL34 was highly expressed in osteosarcoma tissues when compared to adjacent tissues and normal bone tissues. Survival analysis showed that high expression of RPL34 predicted a poor prognosis for osteosarcoma patients. Knockdown of RPL34 in Saos-2 cells via lentivirus-mediated small interfering RNA (siRNA) significantly inhibited cell proliferation, induced cell apoptosis and G2/M phase arrest. Moreover, screening of transcription factors using University of California Santa Cruz (UCSC) Genome Browser, protein-protein interaction (PPI) network analysis, Gene Ontology (GO) and pathway enrichment analysis revealed that MYC participates in the transcriptional regulation of RPL34, which interacts with the subunits of eukaryotic translation initiation factor 3 (eIF3) and probably involves the translational control of growth-promoting proteins. Our findings suggest that RPL34 plays an important role in the proliferation of osteosarcoma cells.

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Osteosarcoma is the most frequent malignant primary bone tumor. GRM4 is expressed in human osteosarcoma cells, and high expression of mGluR4 in osteosarcoma tissues is related to poor prognosis. The aim of this study was to investigate the association between polymorphism of the GRM4 gene and the susceptibility to osteosarcoma in a Chinese population. In a case-control study, we investigated polymorphisms in the GRM4 gene (rs2229901, rs733457, and rs1906953) with a real-time quantitative polymerase chain reaction (PCR) assay (TaqMan). The study was conducted with 126 Chinese patients with osteosarcoma and 168 Chinese subjects in a control group. Unconditional logistic regression was used to analyze the correlation between single nucleotide polymorphisms (SNPs) and osteosarcoma risk. Different survival rates of different genotypic patients with osteosarcoma were analyzed through Kaplan-Meier. There were statistically significant differences in the distributions of the rs1906953 genotypes between the cases and control group (P = 0.034). However, there was no remarkable difference in the three genotypes of GRM4 gene rs2229901 locus between the patient group and control group (P = 0.369). Survival analysis for rs1906953 showed that the median survival time of osteosarcoma patients with the CC genotype was significantly shorter compared to the CT and TT genotypes; patients carrying CC genotype have apparently got a decrease in their recurrence-free survival time in comparison with patients carrying TT genotype. Our data suggest that GRM4 gene polymorphism is closely related to the morbidity and metastasis of osteosarcoma in a Chinese population.

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STUDY STRATEGY: A retrospective clinic study. PURPOSE: To evaluate the efficacy of conservative and surgical treatment for lumbosacral tuberculosis. METHODS: This study retrospectively reviewed 53 patients with lumbosacral tuberculosis who were treated in our institution between January 2005 and January 2011. There were 29 males and 24 females with average ages of 37.53 ± 17.28 years (range 6-72 years). 11 patients were given only anti-TB drugs; the remainder underwent anterior debridement, interbody fusion with and without instrumentation, or one-stage anterior debridement combined with posterior instrumentation. Outcome data for these patients included neurologic status, lumbosacral angle, erythrocyte sedimentation rate value(ESR) and C-reactive protein value(CRP) were assessed before and after treatment. RESULTS: The mean lumbosacral angles were 23.00°± 2.90° in the conservatively treated patients and 22.36°± 3.92o in the surgically treated patients. At the final follow-up, this had improved to 24.10o ± 2.96° in the conservatively treated patients and 28.13° ± 1.93° in the surgically treated patients (all P < 0.05). There were statistically significant differences before and after treatment in terms of ESR and CRP (all P < 0.05). All patients achieved bone fusion. The mean follow-up period was 32.34 ± 8.13 months (range 18 to 55 months). The neurological deficit did not worsen in any of the patients. CONCLUSIONS: It has been proven that conservative and surgical treatments are safe and effective and produce good clinical outcomes for patients with lumbosacral tuberculosis. The advantages of operation include thoroughness of debridement, decompression of the spinal cord, and adequate spinal stabilization.

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