Methylprednisolone Inhibits Autophagy of Vascular Endothelial Cells in Rat Femoral Head Via PI3K/Akt/mTOR Pathway.

OBJECTIVE: To study the relationship between vascular endothelial cells (VEC) and autophagy, and its regulatory mechanism in steroid-induced avascular necrosis of the femoral head (SANFH). METHODS: In cell experiment, VEC were isolated and cultured from the femoral head of Sprague-Dawley rats and divided into three groups: blank control group (Ctrl), methylprednisolone group (MP), and methylprednisolone+mTOR-shRNA group (MP + shmTOR). The autophagy formation was observed by transmission electron microscope. The mRNA expression of PI3K, Akt, mTOR, Beclin1 and MAP1LC3 was detected by RT-PCR and the protein expression was detected by Western blot and immunofluorescence. Expression of the damage marker 6-keto-PGF1α was detected by the ELISA method. In vivo experiment, after establishing the model, the grouping method was the same as cell experiment. Autophagosomes were observed by same method, and the expression of related factors was detected by the same method in cell experiment. RESULTS: In the cell experiment, autophagosomes in the MP group were significantly lower than in the Ctrl group, and the autophagosomes in the MP + shmTOR group were intermediate between two groups (P < 0.05). The mRNA expression levels of PI3K, Akt and mTOR in the MP group were significantly higher than in the Ctrl group, while the MP+ shmTOR group presented intermediate levels between these groups (average gray value were 3837.90, 2996.30, 3005.60, F = 428.64, P < 0.05). MRNA expression levels of Beclin1 and MAP1LC3 in the MP group were significantly lower than that in Ctrl group (P < 0.05). The content of 6-keto-PGF1α in the MP + shmTOR group was higher than in the Ctrl group and lower than in the MP group at the evaluated time intervals (average absorbance value were 104.98, 206.83, 145.91, F = 352.83, P < 0.01). In vivo experiment, the content of 6-Keto-PGF1α in the hormone group increased as time went on; the mTOR-si group was higher than that in control group, but lower than that in the hormone group (P < 0.01). The mRNA expressions of Beclin1 and MAP1LC3 in the control group were higher than those in the hormone group, while the mRNA expressions of PI3K, Akt and mTOR were lower than those in the mTOR-si group (P < 0.05). CONCLUSION: The steroid inhibited the physiological protective effect of autophagy on SANFH by increasing the expression of PI3K/Akt/mTOR signaling pathway related factors and decreasing the expression of Beclin1 and MAP1LC3 in the femoral head VEC.

Sacral and thoracic chordoma with pulmonary metastases: A case report and review of the literature.

Chordoma is a sporadic type of cancer that affects the spine and is particularly challenging to treat due to the paucity of reported cases and scientific literature. In particular, primary chordomas affecting both the sacral and thoracic vertebrae are extremely rare. We herein report a rare case of chordoma in the sacral and thoracic vertebrae with pulmonary metastasis, along with a literature review. The objective of the present study was to explore treatment options and long-term outcomes in patients with metastatic chordoma. Posterior decompression was performed for the thoracic tumor, followed by extended resection of the sacral tumor. The symptoms of the patient were relieved after surgery, and the postoperative Nurick score decreased from grade 3 to grade 2, while the postoperative McCormick score was I. Therefore, complete chordoma excision and internal spinal fixation may effectively reduce tumor recurrence and metastasis.

MicroRNA­22 regulates autophagy and apoptosis in cisplatin resistance of osteosarcoma.

Osteosarcoma (OS) is a primary malignant tumor of bone tissue. Effective chemotherapy may improve the survival of patients with OS. MicroRNAs (miRs) serve significant roles in the regulatory function of tumorigenesis and chemosensitivity of different types of cancer. miR­22 has been revealed to inhibit the proliferation and migration of OS cells, as well as increasing their sensitivity to cisplatin (CDDP). The mechanisms of action behind the functions of miR­22 in OS drug resistance require investigation. Therefore, in the present study, the human OS cell lines (MG­63, U2OS, Saos2 and OS9901) and a drug­resistant cell line (MG­63/CDDP) were cultured. Cell proliferation, apoptosis and autophagy assays were performed to investigate the proliferation, apoptosis and autophagy of cell lines transfected with miR­22 mimic. Reverse transcription­quantitative polymerase chain reaction and western blot analysis were performed to investigate the expression levels of associated genes. The results revealed that miR­22 inhibited the proliferation of MG­63 cells and MG­63/CDDP cells, and enhanced the anti­proliferative ability of CDDP. miR­22 induced apoptosis and inhibited autophagy of MG­63 cells and MG­63/CDDP cells. Apoptosis­related genes, including caspase­3 and Bcl­2­associated X protein were upregulated, while B­cell lymphoma­2 was downregulated in both cell lines transfected with the miR­22 mimic. Autophagy protein 5, beclin1 and microtubules­associated protein 1 light chain 3 were downregulated in both cell lines transfected with miR­22 mimic. Furthermore, the in vitro and in vivo expression levels of metadherin (MTDH) in the OS/OS­CDDP­resistant models were downregulated following transfection with the miR­22 mimic. Therefore, the results of the present study suggested that miR­22 promoted CDDP sensitivity by inhibiting autophagy and inducing apoptosis in OS cells, while MTDH may serve a positive role in inducing CDDP resistance of OS cells.

MicroRNA­22 mediates the cisplatin resistance of osteosarcoma cells by inhibiting autophagy via the PI3K/Akt/mTOR pathway.

Osteosarcoma (OS) is the most common primary malignant tumor of the bone affecting children and adolescents. Chemotherapy is now considered as a standard component of OS treatment, not only for children, but also for adults. However, chemoresistance continues to pose a challenge to therapy. Inhibition of autophagy has been demonstrated to decrease chemoresistance in OS. Moreover, microRNA­22 (miR­22) inhibits autophagy, leading to an improvement in the sensitivity of cisplatin (CDDP) in OS. The aim of the present study was therefore to investigate whether miR­22 could mediate the CDDP resistance of OS cells by inhibiting autophagy via the phosphoinositide 3­kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway. Cell proliferation assay, LC3 flow cytometry assay and monodansylcadaverine staining in MG63 cells and CDDP resistance cells (MG63/CDDP) were performed to explore to role of miR­22 and CDDP in OS chemoresistance. Inoculation of tumor cells in an in vivo model, reverse transcription­quantitative PCR (RT­qPCR) assay, western blot analysis, and immunohistochemistry analysis were performed to investigate the role of miR­22 and CDDP in the PI3K/Akt/mTOR pathway as it is affected by autophagy. The results revealed that miR­22 inhibited the proliferation of MG63 and MG63/CDDP cells, and enhanced the anti­proliferative ability of CDDP in vivo and in vitro. miR­22 mediated the CDDP resistance of OS cells by inhibiting autophagy and decreasing CDDP­induced autophagy via downregulation of the expression of PI3K, Akt, and mTOR at the mRNA level, and the expression of PI3K, phosphorylated (p)­Akt, and p­mTOR at the protein level. It was also convincingly demonstrated that miR­22 mediates the CDDP resistance of OS by inhibiting autophagy via the PI3K/Akt/mTOR pathway. Furthermore, in the MG63 cells that were affected by CDDP, the role of miR­22 was shown to be similar to that of the investigated inhibitor of PI3K (wortmannin) in terms of regulating the PI3K/Akt/mTOR pathway, and wortmannin could also promote the effect of miR­22. Interestingly, CDDP was demonstrated to induce autophagy by inhibiting the PI3K/Akt/mTOR pathway, whereas the pathway was upregulated in the state of chemoresistance. In conclusion, downregulation of the PI3K/Akt/mTOR pathway was shown to assist in the process of preventing chemoresistance.

Mechanism of Methylprednisolone-Induced Primary Cilia Formation Disorder and Autophagy in Osteoblasts.

OBJECTIVE: To study the role of primary cilia formation disorder and osteoblasts autophagy in the pathogenesis of steroid-induced avascular necrosis of the femoral head (SANFH). METHODS: Osteoblasts were isolated from rabbit bones and treated with 1 µM Methylprednisolone for 0, 12, 24, 48, and 72 h. The Beclin1, MAP1LC3, Atg-5, Atg-12, IFT20 and OFD1 mRNAs and proteins were detected by PCR and Western blotting, and their correlation was statistically analyzed. The lengths of osteoblast cilia were measured under a laser confocal microscope, and the autophagy flux was tracked by transfecting the osteoblasts with GFP-RFP-LC3 lentivirus. RESULTS: Methylprednisolone significantly upregulated Beclin1, MAP1LC3, Atg-5, Atg-12 and OFD1 mRNAs and proteins in a time-dependent manner, and decreased that of IFT20 (P < 0.05). In addition, the autophagy flux in the osteoblasts also increased and the ciliary length decreased in a time-dependent manner after Methylprednisolone treatment. The length of the cilia were 5.46 ± 0.11 um at 0 h, 4.08 ± 0.09 um at 12 h, 3.07 ± 0.07 um at 24 h, 2.31 ± 0.10 um at 48 h, and finally 1.15 ± 0.04 um at 72 h. Methylprednisolone treatment also affects primary cilium numbers in cultures, for 0 to 72 h. The autophagy regulatory genes, Beclin1, MAP1LC3, Atg-5 and Atg-12, were found to be negatively correlated with IFT20, with an average correlation coefficient of -0.81. A negative correlation was also found between OFD1 and IFT20, with an average correlation coefficient of -0.53. CONCLUSION: Methylprednisolone inhibits primary cilia formation and promotes autophagy, which could be the pathological basis of SANFH. The exact regulatory mechanism needs to be further studied in vivo.

Influence of MicroRNA-141 on Inhibition of the Proliferation of Bone Marrow Mesenchymal Stem Cells in Steroid-Induced Osteonecrosis via SOX11.

OBJECTIVE: To investigate whether miR-141 and the sex determination region of Y chromosome box 11 (SOX11) play roles in steroid-induced avascular necrosis of the femoral head (SANFH), and to explore whether miR-141 could target SOX11 to influence the proliferation of bone marrow mesenchymal stem cells (BMSC). METHODS: Bone marrow mesenchymal stem cells (BMSC) were isolated and cultured from 4-week-old Sprague Dawley rats. A flow cytometry assay was performed to identify BMSC. BMSC were divided into two groups: a control group and a dexamethasone (DEX) group. BMSC were transfected by miR-141 mimic, miR-141 inhibitor, and SOX11. Real-time polymerase chain reaction (PCR) assay was performed to investigate the mRNA expression of miR-141 and SOX11. The results were used to determine the effect of transfection and to verify the expression in each group and the association between miR-141 and SOX11. Luciferase reporter assay revealed the targeted binding site between miR-141 and the 3'-untranslated region of SOX11 mRNA. MTT assays were performed to investigate the proliferation of BMSC in the miR-141 mimic, miR-141 inhibitor, and SOX11 groups. RESULT: The results of the flow cytometry assay suggested that cells were positive for CD29 and CD90 while negative for CD45. This meant that the isolated and cultured cells were not hematopoietic stem cells. In addition, cell transfection was successful based on the expression of miR-141 and SOX11. According to the results of real-time PCR assay, the mRNA expression of miR-141 in SANFH was upregulated (4.117 ± 0.042 vs 1 ± 0.027, P < 0.001), while SOX11 was downregulated (0.611 ± 0.055 vs 1 ± 0.027, P < 0.001) compared with the control group. Based on the results of the luciferase experiment, MiR-141 could directly target the expression of SOX11. Inhibition of miR-141 could upregulate the expression of SOX11 (2.623 ± 0.220 vs 1 ± 0.095, P < 0.001) according to the results of a real-time PCR assay. MiR-141 inhibited the proliferation of BMSC (0.618 ± 0.092 vs 1.004 ± 0.082, P < 0.001), while suppression of miR-141 increased the proliferation of BMSC (0.960 ± 0.095 vs 0.742 ± 0.091, P < 0.001). Furthermore, according to the results of the MTT assay, SOX11 promoted the proliferation of BMSC (1.064 ± 0.093 vs 0.747 ± 0.090, P < 0.001). CONCLUSION: MiR-141 inhibited the proliferation of BMSC in SANFH by targeting SOX11. Inhibition of miR-141 upregulated the expression of SOX11 and promoted the proliferation of BMSC. MiR-141 and SOX11 could be new targets for investigating the mechanism of SANFH.

Comparison of outcomes of 2 surgical treatments for proximal humerus giant cell tumors: a multicenter retrospective study.

BACKGROUND: The incidence of giant cell tumors in the proximal humerus is low. We evaluated 2 surgical treatments for giant cell tumors of the proximal humerus and postoperative upper-extremity function. METHODS: This study retrospectively analyzed the clinical data of 27 cases of giant cell tumors of the proximal humerus at 4 Chinese medical centers specializing in bone oncology collected between January 2002 and June 2015. All patients were followed up for more than 2 years. The surgical procedures performed for treatment included curettage in 14 patients and segmental resection in 13. The Campanacci grade, occurrence of pathologic fracture, surgical method, complications, and Musculoskeletal Tumor Society score were recorded for each cohort. RESULTS: The recurrence rate was 7.1% in the curettage group and 15.4% in the segmental resection group. Other postoperative complications occurred in 4 patients with segmental resection, including resorption of the osteoarticular allograft in 2, subluxation of the glenohumeral joint in 1, and prosthetic loosening and exposure in 1. A significant difference in postoperative upper-extremity function was noted between the 2 groups (P < .001). CONCLUSIONS: Postoperative upper-extremity function in the curettage group was significantly better than that in the segmental resection group. Segmental resection and reconstruction with a large segmental osteoarticular allograft were considered unadvisable. We suggest that extensive curettage should be selected to treat proximal humerus giant cell tumors as much as possible.

Roles of microRNA-22 in Suppressing Proliferation and Promoting Sensitivity of Osteosarcoma Cells via Metadherin-mediated Autophagy.

OBJECTIVE: To analyze the effect of microRNA-22 on autophagy and proliferation and to investigate the underlying molecular mechanism of osteosarcoma cell chemotherapy sensitivity. METHODS: MG-63 cells were divided into four groups, including a control group, a negative control (NC) group, a cisplatin group, and a cisplatin + miR-22 group. Proliferation of MG-63 cells that had been treated with cisplatin and transfected with miR-22 mimics was determined using MTT assay and colony formation assay. We assessed the degree of autophagy using flow cytometry through cellular staining of the autophagy lysosomal marker monodansylcadaverine (MDC). The effect of microRNA-22 on autophagy was observed along with the expression levels of Beclin1, LC3, metadherin (MTDH) and ATG5 by western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Luciferase reporter assay revealed the targeted binding site between miR-22 and the 3'-untranslated region (3'-UTR) of MTDH mRNA. Western blot and qRT-PCR were used to explore the level of MTDH in the control group, the NC group, the cisplatin group, and the miR-22 group for 6, 12, and 24 h. RESULTS: In the in vitro study, the MTT results indicated that the MG-63 cells with overexpression of miR-22 exhibited a significant decline in the proliferation capacity compared with the control group (0.513 ± 0.001, P < 0.0005). Similar to the MTT results, MG-63 cells that were transfected with miR-22 mimic (101.0 ± 10.58) formed fewer colonies compared with the cisplatin group (129.7 ± 4.163). MDC staining revealed that miR-22-overexpressing osteosarcoma (OS) cells treated with cisplatin showed a significant decrease in the expression of autophagy (7.747 ± 0.117, P < 0.0001). Our data revealed that miR-22 could regulate not only autophagy but also proliferation in the chemosensitivity of osteosarcoma cells. We found that miR-22 sensitized osteosarcoma cells to cisplatin treatment by regulating autophagy-related genes. In addition, Luciferase Reporter Assay revealed that miR-22 negatively regulated autophagy through direct targeting of MTDH. We performed western blot analysis to detect the MTDH expression level. The results revealed that the overexpression of miR-22 obviously decreased the expression of MTDH (1.081 ± 0.023, P < 0.001). CONCLUSION: Inhibition of miR-22 ameliorated the anticancer drug-induced cell proliferation decrease in osteosarcoma cells. MTDH was identified as the miR-22 target in OS cells and MTDH-triggered autophagy played a key function in the miR-22-associated chemotherapy sensitivity.