Integrating single-cell and spatial transcriptomics reveals endoplasmic reticulum stress-related CAF subpopulations associated with chordoma progression.

BACKGROUND: With cancer-associated fibroblasts (CAFs) as the main cell type, the rich myxoid stromal components in chordoma tissues may likely contribute to its development and progression. METHODS: Single-cell RNA sequencing (scRNA-seq), spatial transcriptomics, bulk RNA-seq, and multiplexed quantitative immunofluorescence (QIF) were used to dissect the heterogeneity, spatial distribution, and clinical implication of CAFs in chordoma. RESULTS: We sequenced here 72 097 single cells from 3 primary and 3 recurrent tumor samples, as well as 3 nucleus pulposus samples as controls using scRNA-seq. We identified a unique cluster of CAF in recurrent tumors that highly expressed hypoxic genes and was functionally enriched in endoplasmic reticulum stress (ERS). Pseudotime trajectory and cell communication analyses showed that this ERS-CAF subpopulation originated from normal fibroblasts and widely interacted with tumoral and immune cells. Analyzing the bulk RNA-seq data from 126 patients, we found that the ERS-CAF signature score was associated with the invasion and poor prognosis of chordoma. By integrating the results of scRNA-seq with spatial transcriptomics, we demonstrated the existence of ERS-CAF in chordoma tissues and revealed that this CAF subtype displayed the most proximity to its surrounding tumor cells. In subsequent QIF validation involving 105 additional patients, we confirmed that ERS-CAF was abundant in the chordoma microenvironment and located close to tumor cells. Furthermore, both ERS-CAF density and its distance to tumor cells were correlated with tumor malignant phenotype and adverse patient outcomes. CONCLUSIONS: These findings depict the CAF landscape for chordoma and may provide insights into the development of novel treatment approaches.

Corrigendum: Coexpression of HHLA2 and PD-L1 on tumor cells independently predicts the survival of spinal chordoma patients.

[This corrects the article DOI: 10.3389/fimmu.2021.797407.].

Clinicopathological and Prognostic Characteristics in Spinal Chondroblastomas: A Pooled Analysis of Individual Patient Data From a Single Institute and 27 Studies.

STUDY DESIGN: Retrospective pooled analysis of individual patient data. OBJECTIVES: Spinal chondroblastoma (CB) is a very rare pathology and its clinicopathological and prognostic features remain unclear. Here, we sought to characterize the clinicopathological data of a large spinal CB cohort and determine factors affecting the local recurrence-free survival (LRFS) and overall survival (OS) of patients. METHODS: Electronic searches using Medline, Embase, Google Scholar and Wanfang databases were performed to identify eligible studies per predefined criteria. A retrospective review was also conducted to include additional patients at our center. RESULTS: Twenty-seven studies from the literature and 8 patients from our local institute were identified, yielding a total of 61 patients for analysis. Overall, there were no differences in clinicopathological characteristics between the local and literature cohorts, except for absence or presence of spinal canal invasion by tumor on imagings and chicken-wire calcification in tumor tissues. Univariate Kaplan-Meier analysis revealed that previous treatment, preoperative or postoperative neurological deficits, type of tumor resection, secondary aneurysmal bone cyst (ABC), chicken-wire calcification and radiotherapy correlated closely with LRFS, though only type of tumor resection, chicken-wire calcification and radiotherapy were predictive of outcome based on multivariate Cox analysis. Analyzing OS, we found that a history of preoperative treatment, concurrent ABC, chicken-wire calcification, type of tumor resection and adjuvant radiotherapy had a significant association with survival, whereas only type of tumor resection remained statistically significant after adjusting for other covariables. CONCLUSION: These data may be helpful in prognostic risk stratification and individualized therapy decision making for patients.

Incidence and Risk Factors for Cerebrovascular-Specific Mortality in Patients with Colorectal Cancer: A Registry-Based Cohort Study Involving 563,298 Patients.

BACKGROUND: Colorectal cancer (CRC) is one of the most prevalent diseases and the second leading cause of death worldwide. However, the relationship between CRC and cerebrovascular-specific mortality (CVSM) remains elusive, and less is known about the influencing factors associated with CVSM in CRC. Here, we aimed to analyze the incidence as well as the risk factors of CVSM in CRC. METHODS: Patients with a primary CRC diagnosed between 1973 and 2015 were identified from the Surveillance Epidemiology and End Results database, with follow-up data available until 31 December 2016. Conditional standardized mortality ratios were calculated to compare the incidence of CVSM between CRC patients and the general U.S. POPULATION: Univariate and multivariate survival analyses with a competing risk model were used to interrogate the risk factors for CVSM. RESULTS: A total of 563,298 CRC individuals were included. The CVSM in CRC patients was significantly higher than the general population in all age subgroups. Among the competing causes of death in patients, the cumulative mortality caused by cerebrovascular-specific diseases steadily increased during the study period. While age, surgery, other/unknown race and tumors located at the transverse colon positively influenced CVSM on both univariate and multivariate analyses, male patients and those who had radiotherapy, chemotherapy, a more recent year (2001-2015) of diagnosis, a grade II or III CRC, rectal cancer, or multiple primary or distant tumors experienced a lower risk of CVSM. INTERPRETATION: Our data suggest a potential role for CRC in the incidence of CVSM and also identify several significant predictors of CVSM that may be helpful for risk stratification and the therapeutic optimization of cerebrovascular-specific diseases in CRC patients.

LncRNA HOTAIR influences cell proliferation via miR-130b/PTEN/AKT axis in IDD.

Intervertebral disc degeneration (IDD) constitutes the pathological foundation of most musculoskeletal disorders of the spine. Previous studies have noted that cell proliferation is a common feature of IDD. Bioinformatics indicated that aberrantly expressed long non-coding RNAs (lncRNAs) were involved in the development of IDD. In this study, we aimed to investigate the function of lncRNA HOTAIR in the proliferation of human nucleus pulposus (NP) cells of IDD in vitro and further clarified its mechanism. The expression of HOTAIR and miR-130b was quantified by qRT-PCR in nucleus pulposus (NP) tissues. Furthermore, NP cells proliferation were assayed by CCK8 and Immunostaining. Dual-luciferase reporter and RIP assay were used to examine the expression of HOTAIR, PTEN, and their co-target gene miR-130b. Western blotting was used to test AKT expression. Our in vitro experiments on human normal NP cells observed that HOTAIR was significantly dysregulated in IDD. Further, HOTAIR can suppress proliferation by directly targeting miR-130b. In addition, Both HOTAIR and PTEN were confirmed to target miR-130b, and miR-130b upregulation reversed the phenomenon of ectopic expression of HOTAIR. More importantly, HOTAIR upregulation significantly reduced CyclinD1 protein expression by PTEN/AKT signaling pathway. Our findings suggest that HOTAIR may bind to miR-130b and subsequently increased CyclinD1 expression via PTEN/Akt pathway. Thereby, HOTAIR could become a potential target for the treatment of IDD.Abbreviations : IDD; intervertebral disc degeneration ncRNAs; non-coding RNAs lncRNAs; long non-coding RNAs miRNAs; microRNAs NP; nucleus pulposus qRT-PCR; quantitative reverse transcription-PCR LBP; Low back pain ORF; open reading frame HOTAIR; Hox transcript antisense intergenic RNA FAF1; Fas-associated protein factor-1 Erk; extracellular signal-regulated kinase TUG1; Taurine Up-regulated Gene 1 HIF1A hypoxia-inducible factor 1-alpha PI3K; phosphoinositide-3 kinase AIS; adolescent idiopathic scoliosis ECM; extracellular matrix LN;lupus nephritis CT;computed tomography MRI; magnetic resonance imaging PBS; phosphate-buffered salin PBS; phosphate-buffered salin PVDF; polyvinylidene fluoride TBST; Tris-buffered saline Tween ECL; enhanced chemiluminescence RIP; RNA immunoprecipitation.

A novel rat model of interbody fusion based on anterior lumbar corpectomy and fusion (ALCF).

BACKGROUND: Rats have been widely used as experimental animals when performing fundamental research because they are economical, rapidly reproducing, and heal quickly. While the rat interbody fusion model has been applied in basic studies, existing rat models generally have shortcomings, such as insufficiently simulating clinical surgery. The purpose of this study was to develop a novel rat model of interbody fusion which more closely represents clinical surgery. METHODS: The internal fixation was designed based on physical measurements of the rats' lumbar spine. Then, ten rats divided into two groups (A and B) underwent anterior lumbar corpectomy and fusion of the L5 vertebrae. Groups A and B were sacrificed four and 8 weeks post-surgery, respectively. Micro-CT and histological examination were used to evaluate the model. Fusion rate, bone volume fraction (BV/TV), trabecular bone number (Tb.N), trabecular bone thickness (Tb.Th), and the area ratio of newly formed bone (NB) were calculated for quantitative analysis. RESULTS: Based on the L5 body dimensions of individual rats, 3D-printed titanium cage of the appropriate size were printed. The operations were successfully completed in all ten rats, and X-ray confirmed that internal fixation was good without migration. Micro-CT suggested that fusion rates in group B (100%) were greater than group A (40%, P < 0.05). The BV/TV (B: 42.20 ± 10.50 vs. A: 29.02 ± 3.25, P < 0.05) and Tb.N (B: 4.66 ± 1.23 vs. A: 1.97 ± 0.40, P < 0.05) were greater in group B than A, and the Tb.Th in group B was lower than group A (B: 0.10 ± 0.04 vs. A: 0.15 ± 0.02, P < 0.05). Histomorphometry results demonstrated that the area ratio of NB in group B were greater than group A (B: 35.72 ± 12.80 vs. A: 12.36 ± 16.93, P < 0.05). CONCLUSION: A rat interbody fusion model based on anterior lumbar corpectomy and fusion has successfully been constructed and verified. It could provide a new choice for fundamental research using animal models of spinal fusion.

Clinicopathological and Prognostic Characteristics in Dedifferentiated/Poorly Differentiated Chordomas: A Pooled Analysis of Individual Patient Data From 58 Studies and Comparison With Conventional Chordomas.

BACKGROUND: Currently, the clinicopathological and prognostic characteristics of dedifferentiated chordoma (DC) and poorly differentiated chordoma (PDC) remain poorly understood. In this study, we sought to characterize clinicopathological parameters in a large PDC/DC cohort and determine their correlations with progression-free survival (PFS) and overall survival (OS) of patients. We also attempted to compare clinical features between PDC/DC and conventional chordoma (CC). METHODS: Literature searches (from inception to June 01, 2020) using Medline, Embase, Google Scholar and Wanfang databases were conducted to identify eligible studies according to predefined criteria. The local database at our center was also retrospectively reviewed to include CC patients for comparative analysis. RESULTS: Fifty-eight studies from the literature and 90 CC patients from our local institute were identified; in total, 54 PDC patients and 96 DC patients were analyzed. Overall, PDC or DC had distinct characteristics from CC, while PDC and DC shared similar clinical features. Adjuvant radiotherapy and chemotherapy were associated with both PFS and OS in PDC patients in the univariate and/or multivariate analyses. In the DC cohort, tumor resection type, adjuvant chemotherapy and tumor dedifferentiation components significantly affected PFS, whereas none of them were predictive of outcome in the multivariate analysis. By analyzing OS, we found that surgery, resection type and the time to dedifferentiation predicted the survival of DC patients; however, only surgery remained significant after adjusting for other covariables. CONCLUSIONS: These data may offer useful information to better understand the clinical characteristics of PDC/DC and may be helpful in improving the outcome prediction of patients.

Prognostic Significance of Tumor-Associated Macrophages in Chondroblastoma and Their Association with Response to Adjuvant Radiotherapy.

OBJECTIVE: Chondroblastoma (CB) is a rare and locally growing cartilage-derived tumor. Currently, clinical implications of tumor-associated macrophages (TAMs) in CB remain unclear. In this study, we sought to analyze the relationship between TAM parameters (including densities of CD68+ and CD163+ cells as well as the CD163+/CD68+ ratio) and clinicopathological characteristics and survival of patients. METHODS: Immunohistochemistry was used to assess TAM subtypes for CD68 and CD163, as well as the expression levels of p53, CD34, and Ki-67 on tumor cells in 132 tissue specimens retrieved between July 2002 and April 2020. Then, TAM parameters were retrospectively analyzed for their associations with patient outcomes (local recurrence-free survival [LRFS] and overall survival [OS]) and clinicopathological features. RESULTS: TAM densities were significantly higher in axial chondroblastoma tissue than in extra-axial chondroblastoma tissue. Moreover, the number of CD163+ TAMs was positively correlated with tumor invasion of surrounding tissues and high expression of CD34 and Ki-67 on tumor cells, whereas CD163+ cell density and the CD163/CD68 ratio were negatively associated with patient response to adjuvant radiotherapy. Univariate Kaplan-Meier analysis revealed that the number of CD68+ and CD163+ lymphocytes was significantly associated with both LRFS and OS. Multivariate Cox regression analysis showed that CD163+ and CD68+ cell levels were independent prognostic factors of LRFS, while TAM data independently predicted OS. More importantly, in subgroup analysis based on three significant factors in univariate survival analysis (including tumor location, adjuvant radiotherapy, and surrounding tissue invasion by tumors), the TAM parameters still displayed good prognostic performance. CONCLUSION: These data suggest that TAM may significantly affect the biological behavior of CB. We hypothesize that modulating the TAM level or polarization status in the microenvironment may be an effective approach for CB treatment.

Coexpression of HHLA2 and PD-L1 on Tumor Cells Independently Predicts the Survival of Spinal Chordoma Patients.

Background: Immunotherapy only achieves efficacy in some cancer patients, and less is known about other immune checkpoint molecules in chordoma. Here, we aimed to determine the expression of PD-L1, HHLA2, B7H3, IDO-1 and Galectin-9 in spinal chordoma and evaluated their association with tumor infiltrating lymphocytes (TILs), clinicopathological characteristics and survival of patients. Methods: Using multiplexed quantitative immunofluorescence (QIF), we simultaneously measured the levels of five different immune checkpoint molecules and major TIL subsets in 92 human spinal chordoma samples. Results: Tumor HHLA2 and PD-L1 were positive in 80.0% and 86.0% of cases, respectively. However, B7H3, IDO-1 and Galectin-9 positivity on tumor cells were only seen in 21.0% of cases, despite all showing predominantly stromal expression. Coexpression of these QIF markers in the tumor compartment was scarcely detected except for PD-L1 and HHLA2, which was observed in 69.6% of cases. While tumoral HHLA2 and stromal B7H3 expressions were associated with an aggressive tumor phenotype, suppressive immune response (specifically including elevated PD-1+ TILs level and decreased CD8+ TIL density) and poor prognosis, stromal levels of PD-L1 and Galectin-9 predicted the opposite outcomes. Importantly, HHLA2 and PD-L1 coexpression on tumor cells independently predicted both worse local recurrence-free survival and overall survival. Conclusion: These data provide a better understanding of the immunosuppressive mechanism in chordoma and may be useful for the development of combination or novel immunotherapy approaches aiming to improve therapeutic efficacy and survival.

Development and Validation of a 6-miRNA Prognostic Signature in Spinal Chordoma.

BACKGROUND: Published data have suggested a critical role for microRNA (miRNA) expression in chordoma progression. However, most of these studies focus on single miRNA and no multi-miRNA prognostic signature has been currently established for chordoma. In this study, we sought to develop and validate a 6-miRNA risk score (miRscore) model for survival prediction. METHODS: Medline, Embase, and Google scholar searches (from inception to July 20, 2018) were conducted to identify candidate miRNAs with prognostic value as per predefined criteria. Quantitative RT-PCR was used to measure miRNA levels in 114 spinal chordoma (54 in the training and 60 in the validation cohort) and 20 control specimens. Subsequently, the miRscore was built based on miRNAs data. RESULTS: Literature searches identified six prognostic miRNAs (miR-574-3p, miR-1237-3p, miR-140-3p, miR-1, miR-155, and miR-1290) with differential expression in tumor tissues. Bioinformatical analysis revealed an important regulatory role for miR-574-3p/EGFR signaling in chordoma and showed that the target genes of these prognostic miRNAs were mainly enriched in transcription regulation, protein binding and cancer-related pathways. In both cohorts, the miRscore was associated with surrounding muscle invasion by tumor and/or other aggressive features. The miRscore model well predicted local recurrence-free survival and overall survival, which remained after adjusting for other relevant covariates. Further time-dependent receiver operating characteristics analysis in the two cohorts found that the miRscore classifier had stronger prognostic power than known clinical predictors and improved the ability of Enneking staging to predict outcomes. Importantly, recursive-partitioning analysis of both samples combined separated patients into four prognostically distinct risk subgroups for recurrence and survival (both P < 0.001). CONCLUSIONS: These data suggest the miRscore as a useful prognostic stratification tool in spinal chordoma and may represent an important step toward future personalized treatment of patients.

Interleukin-17A Promotes Human Disc Degeneration by Inhibiting Autophagy Through the Activation of the Phosphatidylinositol 3-Kinase/Akt/Bcl2 Signaling Pathway.

BACKGROUND: Previous studies have suggested that interleukin (IL)-17A is a key factor that contributes to intervertebral disc degeneration (IDD), whereas autophagy has been shown to be a protective mechanism in IDD. However, the relationship between IL-17A and autophagy in IDD remains to be fully elucidated. This study sought to evaluate the association between IL-17 and autophagy and the potential mechanism through which IL-17A affects autophagy in IDD. METHODS: Intervertebral disc specimens were collected from 10 patients with lumbar disc herniation. Human degenerated nucleus pulposus (NP) cells were cultured in the presence or absence of IL-17A treatment. Western blot and monodansylcadaverine staining were used to measure autophagy levels in human degenerated NP cells. Subsequently, phosphatidylinositol 3-kinase (PI3K)/Akt/Bcl-2 pathway inhibitors were used to reveal the potential mechanism. RESULTS: IL-17A treatment inhibited the autophagic activity in human NP cells in a time- and dose-dependent manner. Moreover, monodansylcadaverine staining showed that cells treated with IL-17A had significantly fewer changes in their autophagic vacuoles compared with control-treated cells. After IL-17A treatment, expression levels of PI3K, p-Akt, and Bcl-2 in NP cells were significantly increased. Further assays with PI3K/Akt/Bcl-2 inhibitors revealed that IL-17A suppressed autophagy in NP cells by activating the PI3K/Akt/Bcl-2 signaling pathway. CONCLUSIONS: These data suggest that IL-17A promotes IDD by inhibiting autophagy through activation of the PI3K/Akt/Bcl-2 signaling pathway and may offer new insights for targeted therapy of this disease.

[New external spinal skeletal fixation combined with percutaneous injury vertebra bone grafting for the treatment of two-segment thoracolumbar fractures].

OBJECTIVE: To investigate the clinical results of new external spinal skeletal fixation combined with percutaneous injury vertebra bone grafting in the treatment of two-segment thoracolumbar fractures without neural dysfunction. METHODS: The clinical data of 28 patients with two-segment thoracolumbar fractures without neural dysfunction treated from January 2013 to August 2015 were retrospectively analyzed. There were 17 males and 11 females, with a mean age of(37.5±10.3) years (ranging from 19 to 55 years). According to fracture AO classification, all 28 cases were type A, including 2 cases of T10,11, 3 cases of T11,12, 9 cases of T12-L1, 4 cases of L1,2, 5 cases of L2,3, 4 cases of L3,4, 1 case of L4,5. All 28 patients received treatment of new external spinal skeletal fixation and percutaneous injury vertebra bone grafting. Operation time, intraoperative bleeding and related complications were recorded. The informations of vertebral anterior border height percentage and bone fusion were observed by radiography before and after operation, before removed external fixation and final follow-up. Visual analogue scale(VAS) was used to evaluate the clinical effects. RESULTS: All the patients were followed up for 13 to 32 months with an average of (24.5±3.5) months. There was significant difference by the time of 3 days postoperatively, before removed external fixation, final follow-up comparing with the preoperative in vertebral anterior border height percentage and VAS score(P<0.05). There was no significant difference in vertebral anterior border height percentage by the time of 3 days postoperatively, before removed external fixation comparing with final follow-up(P>0.05). While the VAS score showed a gradually declining trend, screw lossening ocurred in 2 cases and nail tracker infection occurred in 1 case after operation, and no other complications were found. CONCLUSIONS: New external spinal skeletal fixation and percutaneous injury vertebra bone grafting can got satisfactory clinical effect in treating two-segment thoracolumbar fractures without neural dysfunction, which is an effective method of minimally invasive surgery.

MiR-21 promotes ECM degradation through inhibiting autophagy via the PTEN/akt/mTOR signaling pathway in human degenerated NP cells.

Intervertebral disc degeneration (IDD) is the most common cause leading to low back pain, a highly prevalent, costly and crippling condition worldwide. Overexpression of miR-21 has been shown to promote proliferation of nucleus pulposus (NP) cells. However, it remains unclear whether miR-21 can promote the degradation of type II collagen (Col II) and aggrecan, two main extracellular matrix components within the disc. Here, the miRNA microassay assay identified 29 differentially expressed miRNAs in NP tissues from IDD patients compared with healthy controls. Following qRT-PCR validation, miR-21 expression was significantly upregulated in degenerated NP tissues, and showed a positive correlation with disc degeneration grade. Through gain-of-function and loss-of-function studies in human NP cells, miR-21 was shown to inhibit autophagy and then upregulate the expression of matrix metalloproteinase (MMP)-3 and MMP-9, leading to increased degradation of Col II and aggrecan. Mechanistically, phosphatase and tensin homolog (PTEN) was identified as a direct target of miR-21, and activated PTEN/ Akt/mammalian target of rapamycin (mTOR) signaling pathway was involved in miR-21-induced autophagy inhibition and Col II and aggrecan breakdown. Taken together, these results suggest that miR-21 contributes to Col II and aggrecan catabolism by inhibiting autophagy via the PTEN/Akt/mTOR signaling pathway in human NP cells.

Application of vascularized fibular graft for reconstruction and stabilization of multilevel cervical tuberculosis: A case report.

Multilevel cervical reconstruction and fusion after cervical tuberculosis has always been a challenge. The current implantation materials for cervical fusion, including titanium mesh, cage, and plate are limited by its inferior biological mechanical characteristics and the properties of the metallic material. This has led to the increased risk of recurrent infection after surgery. In addition, the unique nature of tuberculosis infection results in the low rate of cervical fusion and high risk of recurrence. This case report presents 1 patient who suffered from long segmental cervical tuberculosis and had reconstruction surgery using a vascularized fibula graft. The patient had successful graft incorporation 3 months postsurgery and was followed-up for 30 months. In this review, we detail the advantages of using vascularized fibular grafts and compare it with other types of grafts.

Application of anterior debridement and reconstruction with anatomical screw-plate fixation for lumbosacral tuberculosis: A 2-year-plus follow-up.

This study aimed to determine the efficacy and safety of anterior debridement and reconstruction with anatomical screw-plate fixation in patients with lumbosacral junction tuberculosis (TB).A total of 48 patients (30 males and 18 females) diagnosed with lumbosacral junction TB were included in this study. All patients underwent surgery in our institution from January 2008 to July 2014, using anterior debridement and reconstruction with anatomical screw-plate. Outcome data were evaluated before and after surgery and included lumbosacral angle, Frankel classification, bone fusion, and visual analog scale (VAS) scores.All patients were then followed up for an average of 49.4 months (range, 24-96 months). The mean lumbosacral angle improved from 8.36°â€Š±â€Š5.92° pre-operation to 22.38°â€Š±â€Š4.52° post-operation and 21.13°â€Š±â€Š3.73° during the final follow-up (both P < .05). Solid vertebral fusion was achieved in all patients after 7.6 months on average (range, 6-12 months). No severe complications appeared during operation and post-operation. Neurological performance and VAS scores were significantly improved compared with pre-operation (P < .05).Following standard anti-TB chemotherapy, anterior debridement and reconstruction with anatomical screw-plate fixation may be a feasible and effective therapeutical option for lumbosacral junction TB. This procedure can result in satisfactory bone fusion and deformity correction, and effectively restore lumbosacral junction stability.

OPG rs2073617 polymorphism is associated with upregulated OPG protein expression and an increased risk of intervertebral disc degeneration.

The present study aimed to investigate the associations between three distinct osteoprotegerin (OPG) gene polymorphisms and the risk of intervertebral disc degeneration (IDD). A total of 200 IDD patients and 200 healthy controls were recruited from the Department of Spine Surgery at the First Affiliated Hospital of the University of South China (Hengyang, China) between January 2013 and May 2014. The allele, genotype and haplotype frequency distributions of three OPG polymorphisms in the study and control populations were analyzed by polymerase chain reaction prior to restriction fragment length polymorphism or high resolution melting assays. In addition, serum OPG levels were measured via an ELISA. The genotype and allele frequencies of the OPG rs2073617 polymorphisms were significantly higher in the IDD patients, as compared with the control group (P<0.05). Furthermore, carriers of the C allele exhibited a higher risk of IDD, as compared with carriers of the T allele (P<0.001). Conversely, the genotype and allele frequencies of the two other gene polymorphisms, rs2073618 and rs3102735, showed no significant differences between the patients and controls (P>0.05). The serum OPG levels were significantly higher in IDD patients with TT, TC and CC genotypes at the OPG rs2073617 polymorphism, as compared with the control group (P<0.05). Logistic-regression analysis suggested that high serum levels of OPG were positively correlated with IDD risk, whereas the T-C-A, T-G-A and T-G-G haplotypes were negatively correlated with IDD risk (P<0.05). Furthermore, the G-T-G haplotype was associated with protection against IDD (P=0.008), whereas the G-C-G haplotype was associated with an elevated susceptibility to IDD (P=0.007). The results of the present study suggested that OPG rs2073617 polymorphisms and upregulated serum levels of OPG were associated with an increased risk of IDD, whereas the T-C-A, T-G-A and T-G-G haplotypes were protective factors for IDD. The results of the present study suggested that the OPG gene polymorphism may have an important role in the progression of IDD, and its serum level may function as a valuable predictive indicator of the severity of degenerative disc diseases.

MicroRNAs in osteosarcoma.

Osteosarcoma (OS) is a primary malignant bone tumor with high morbidity that principally emerges in children and adolescents. Presently, the prognosis of OS patients remains poor due to resistance to chemotherapy, highlighting the need for new therapeutic approaches. MicroRNAs (miRNAs), a class of small noncoding RNA molecules, can negatively modulate protein expression at the post-transcriptional level. miRNAs regulate a variety of normal physiologic processes and are involved in tumorigenesis and development of multiple malignancies, including OS. Some miRNAs are differentially expressed in OS tissues, cell lines and serum, and have been shown to correlate with the malignant phenotype and prognosis. These altered miRNAs function as oncogenes or tumor suppressor genes in this process. Moreover, restoration of miRNA expression has shown promise for the treatment of OS. Here, we describe miRNA biochemistry with a focus on expression profile, role and therapeutic potential in OS. A better understanding will facilitate the identification and characterization of novel biomarkers and development of miRNA-targeted therapies.

PI3K/Akt signaling in osteosarcoma.

Osteosarcoma (OS) is the most common nonhematologic bone malignancy in children and adolescents. Despite the advances of adjuvant chemotherapy and significant improvement of survival, the prognosis remains generally poor. As such, the search for more effective anti-OS agents is urgent. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is thought to be one of the most important oncogenic pathways in human cancer. An increasing body of evidence has shown that this pathway is frequently hyperactivated in OS and contributes to disease initiation and development, including tumorigenesis, proliferation, invasion, cell cycle progression, inhibition of apoptosis, angiogenesis, metastasis and chemoresistance. Inhibition of this pathway through small molecule compounds represents an attractive potential therapeutic approach for OS. The aim of this review is to summarize the roles of the PI3K/Akt pathway in the development and progression of OS, and to highlight the therapeutic potential of targeting this signaling pathway. Knowledge obtained from the application of these compounds will help in further understanding the pathogenesis of OS and designing subsequent treatment strategies.