Curcumin inhibits the proliferation and migration of osteosarcoma by regulating the expression of super-enhancer-associated genes. / å§œé»„ç´ é€šè¿‡è°ƒæŽ§è¶ çº§å¢žå¼ºå­ç›¸å ³åŸºå› æŠ‘åˆ¶éª¨è‚‰ç˜¤çš„å¢žæ®–å’Œè¿ç§».

OBJECTIVES: Super-enhancer-associated genes may be closely related to the progression of osteosarcoma, curcumin exhibits a certain inhibitory effect on tumors such as osteosarcoma. This study aims to investigate the effects of curcumin on osteosarcoma in vitro and in vivo, and to determine whether curcumin can inhibit the progression of osteosarcoma by suppressing the expression of super-enhancer-associated genes LIM and senescent cell antigen-like-containing domain 1 (LIMS1), secreted protein acidic and rich in cysteine (SPARC), and sterile alpha motif domain containing 4A (SAMD4A). METHODS: Human osteosarcoma cell lines (MG63 cells or U2OS cells) were treated with 5 to 50 µmol/L curcumin for 24, 48, and 72 hours, followed by the methyl thiazolyl tetrazolium (MTT) assay to detect cell viability. Cells were incubated with dimethyl sulfoxide (DMSO) or curcumin (2.5, 5.0 µmol/L) for 7 days, and a colony formation assay was used to measure in vitro cell proliferation. After treatment with DMSO or curcumin (10, 15 µmol/L), a scratch healing assay and a transwell migration assay were performed to evaluate cell migration ability. Real-time reverse transcription polymerase chain reaction (real-time RT-PCR) and Western blotting were used to detect mRNA and protein expression levels of LIMS1, SPARC, and SAMD4A in the cells. An osteosarcoma-bearing nude mouse model was established, and curcumin was administered via gavage for 14 days to assess the impact of curcumin on tumor volume and weight in vivo. Real-time RT-PCR was used to measure mRNA expression levels of LIMS1, SPARC, and SAMD4A in the cancer and adjacent tissues from 12 osteosarcoma patients. RESULTS: After treating cells with different concentrations of curcumin for 24, 48, and 72 hours, cell viability were all significantly decreased. Compared with the DMSO group, the colony formation rates in the 2.5 µmol/L and 5.0 µmol/L curcumin groups significantly declined (both P<0.01). The scratch healing assay showed that, compared with the DMSO group, the migration rates of cells in the 10 µmol/L and 15 µmol/L curcumin groups were significantly reduced. The exception was the 10 µmol/L curcumin group at 24 h, where the migration rate of U2OS cells did not show a statistically significant difference (P>0.05), while all other differences were statistically significant (P<0.01 or P<0.001). The transwell migration assay results showed that the number of migrating cells in the 10 µmol/L and 15 µmol/L curcumin groups was significantly lower than that in the DMSO group (both P<0.001). In the in vivo tumor-bearing mouse experiment, the curcumin group showed a reduction in tumor mass (P<0.01) and a significant reduction in tumor volume (P<0.001) compared with the control group. Compared with the DMSO group, the mRNA expression levels of LIMS1, SPARC, and SAMD4A in the 10 µmol/L and 15 µmol/L curcumin groups were significantly down-regulated (all P<0.05). Additionally, the protein expression level of LIMS1 in U2OS cells in the 10 µmol/L curcumin group was significantly lower than that in the DMSO group (P<0.05). Compared with adjacent tissues, the mRNA expression level of SPARC in osteosarcoma tissues was significantly increased (P<0.001), while the mRNA expression levels of LIMS1 and SAMD4A did not show statistically significant differences (both P>0.05). CONCLUSIONS: Curcumin inhibits the proliferation and migration of osteosarcoma both in vitro and in vivo, which may be associated with the inactivation of super-enhancer-associated gene LIMS1.

Construction of a Five-Super-Enhancer-Associated-Genes Prognostic Model for Osteosarcoma Patients.

Osteosarcoma is a malignant tumor most commonly arising in children and adolescents and associated with poor prognosis. In recent years, some prognostic models have been constructed to assist clinicians in the treatment of osteosarcoma. However, the prognosis and treatment of patients with osteosarcoma remain unsatisfactory. Notably, super-enhancer (SE)-associated genes strongly promote the progression of osteosarcoma. In the present study, we constructed a novel effective prognostic model using SE-associated genes from osteosarcoma. Five SE-associated genes were initially screened through the least absolute shrinkage and selection operator (Lasso) penalized Cox regression, as well as univariate and multivariate Cox regression analyses. Meanwhile, a risk score model was constructed using the expression of these five genes. The excellent performance of the five-SE-associated-gene-based prognostic model was determined via time-dependent receiver operating characteristic (ROC) curves and Kaplan-Meier curves. Inferior outcome of overall survival (OS) was predicted in the high-risk group. A nomogram based on the polygenic risk score model was further established to validate the performance of the prognostic model. It showed that our prognostic model performed outstandingly in predicting 1-, 3-, and 5-year OS of patients with osteosarcoma. Meanwhile, these five genes also belonged to the hub genes associated with survival and necrosis of osteosarcoma according to the result of weighted gene co-expression network analysis based on the dataset of GSE39058. Therefore, we believe that the five-SE-associated-gene-based prognostic model established in this study can accurately predict the prognosis of patients with osteosarcoma and effectively assist clinicians in treating osteosarcoma in the future.

Functions and Clinical Significance of Super-Enhancers in Bone-Related Diseases.

Super-enhancers (SEs) are a large cluster of cis-regulatory DNA elements that contain many binding motifs, which master transcription factors and cofactors bind to with high density. SEs usually regulate the expression of genes that can control the cell identity and fate, and SEs can be used to explain the patterns of the expression of cell-specific genes. Hence, it shows great potential for application in the treatment of diseases like cancer. At present, the clinical treatments for osteosarcoma, Ewing sarcoma, and other bone-related diseases remain challenging. The poor prognosis and difficult treatment of these diseases imposes heavy economic burden on patients and society. In recent years, research on SEs with respect to bone-related diseases has attracted increasing attention. In this paper, we first review the identification and functional mechanisms of SEs. Then, we integrate the findings of the emerging studies on SEs in bone-related diseases. Finally, we summarize recent strategies for targeting SEs for the treatment of bone-related diseases. This review aims to provide comprehensive insights into the roles of SEs in bone-related diseases.

Corrigendum: Construction of a Five-Super-Enhancer-Associated-Genes Prognostic Model for Osteosarcoma Patients.

[This corrects the article DOI: 10.3389/fcell.2020.598660.].

Relationship between serum level of growth differentiation factors 8, 11 and bone mineral density in girls with anorexia nervosa.

BACKGROUND: Adolescents with anorexia nervosa (AN) have low body mass and low bone mineral density (BMD). Growth differentiation factor 8 (Myostatin, GDF8) and its homologue growth differentiation factor 11 (GDF11), members of the TGF-ß super-family, play an important role in muscle regeneration and bone metabolism in healthy individuals. However, their association with BMD in AN is unknown. The present study was undertaken to investigate the relationship between GDF8, GDF11 and BMD in adolescent girls with AN. METHODS: Serum GDF8, GDF11 and BMD were determined in 25 girls (12-16 years old) with AN and 31 healthy girls (12-16 years old). RESULTS: Growth differentiation factor 8 levels were lower in AN subjects. On the contrary, GDF11 levels were higher in AN subjects than controls. There was no relationship between GDF8 and BMD. A significant negative correlation between GDF11 and BMD was found. In multiple linear stepwise regression analysis, BMI, 25-hydroxyvitamin D, GDF11, or lean mass, but not fat mass and GDF8, were independent predictors of BMD in the AN and control groups separately. CONCLUSIONS: Growth differentiation factor 11 was independent predictor of BMD in girls with AN. It suggested that GDF11 exerts a negative effect on bone mass.