Xuhui Zhou

MALAT1 promotes the proliferation and metastasis of osteosarcoma cells by activating the PI3K/Akt pathway

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), one of the first found cancer-associated long noncoding RNAs (lncRNAs), involves in the development and progression of many types of tumors. An aberrant expression of MALAT1 was observed in hepatocellular carcinoma, cervical cancer, breast cancer, ovarian cancer, and colorectal cancer. However, the exact effects and molecular mechanisms of MALAT1 in osteosarcoma progression are still unknown up to now. Here, we investigated the role of MALAT1 in human osteosarcoma cell lines and clinical tumor samples in order to determine the function of this molecule. In our research, the MALAT1 messenger RNA (mRNA) was highly expressed in human osteosarcoma tissues, and its expression level was closely correlated with pulmonary metastasis. Then, we employed lentivirus-mediated knockdown of MALAT1 in U-2 OS and SaO2 to determine the role of MALAT1 in osteosarcoma cell lines. Lentivirus-mediated MALAT1 small interfering RNA (siRNA) could efficiently downregulated the expression level of MALAT1 in osteosarcoma cell lines. Knockdown of MALAT1 inhibited the proliferation and invasion of human osteosarcoma cell and suppressed its metastasis in vitro and vivo. At the same time, the proliferating cell nuclear antigen (PCNA), matrix metallopeptidase 9 (MMP-9), phosphorylated PI3Kp85α, and Akt expressions were significantly inhibited in MALAT1-deleted cells. These findings indicated that MALAT1 might suppress the tumor growth and metastasis via PI3K/AKT signaling pathway. Taken together, our data indicated that MALAT1 might be an oncogenic lncRNA that promoted proliferation and metastasis of osteosarcoma and could be regarded as a therapeutic target in human osteosarcoma.

Neuron-derived FGF10 ameliorates cerebral ischemia injury via inhibiting NF-κB-dependent neuroinflammation and activating PI3K/Akt survival signaling pathway in mice.

FGF10 is a member of fibroblast growth factors (FGFs). We previously showed that FGF10 protects neuron against oxygen-glucose deprivation injury in vitro; however, the effect of FGF10 in ischemic stroke in vivo is unknown. In the present study, we showed that FGF10 was mainly expressed in neurons but not astrocytes, and detected FGF10 in mouse cerebrospinal fluid. The FGF10 levels in neurons culture medium and cell lysate were much higher than those in astrocytes. FGF10 expression in brain tissue and FGF10 level in CSF were increased in mouse middle cerebral artery occlusion (MCAO) model. Administration of FGF10 into lateral cerebroventricle not only decreased MCAO-induced brain infarct volume and neurological deficit, but also reduced the number of TUNEL-positive cells and activities of Caspases. Moreover, FGF10 treatment depressed the triggered inflammatory factors (TNF-α and IL-6) and NF-κB signaling pathway, and increased phosphorylation of PI3K/Akt signaling pathway. Blockade of PI3K/Akt signaling pathway by wortmannin and Akt1/2-kinase inhibitor, partly compromised the neuroprotection of FGF10. However, blockade of PI3K/Akt signaling pathway did not impair the anti-inflammation action of FGF10. Collectively, our results demonstrate that neuron-derived FGF10 ameliorates cerebral ischemia injury via inhibiting NF-κB-dependent neuroinflammation and activating PI3K/Akt survival signaling pathway in mice.

miR-146b-5p promotes invasion and metastasis contributing to chemoresistance in osteosarcoma by targeting zinc and ring finger 3

Osteosarcoma is the most common human primary malignant bone tumor and recurrences are common due to the development of chemoresistance. However, the underlying molecular mechanism for chemoresistance remains unclear. Recent studies demonstrated that miR-146b-5p, an important regulator in tumorigenesis, was involved in chemoresistance in thyroid cancer, lymphoma. Thus, to confirm the role of miR‑146b-5p in osteosarcoma, the study was divided into three steps: first, miR-146b-5p in paired samples were assessed using a quantitative real-time PCR (qRT-PCR) assay from osteosarcoma patients. Second, to confirm the role of miR-146b-5p, we applied lentivirus system to overexpression and knockdown of miR-146b-5p, respectively, in MG-63 osteosarcoma cell line. Third, luciferase assays were performed to determine whether Wnt/β-catenin pathway participated in the role of miR-146b-5p on chemoresistance. As a result, miR-146b-5p was highly expressed in human osteosarcoma tissues and an elevated expression of miR-146b-5p was observed in human osteosarcoma tissues after chemotherapy. Furthermore, it was shown that miR-146b-5p overexpression promoted migration and invasiveness. miR-146b-5p overexpression also increased resistance to chemotherapy. Moreover, knockdown of miR-146b-5p substantially inhibited migration and invasion of osteosarcoma cells as well as rendered them significantly more sensitive to chemotherapy. Results of western blot assay indicated that miR-146b-5p increased MMP-16 protein expression and showed a decrease of ZNRF3 protein. Whereas, IWR-1-endo, an inhibitor of Wnt/β-catenin, suppressed the decrease in apoptosis of osteosarcoma cells caused by miR-146b-5p overexpression. These results indicated that miR-146b-5p promoted proliferation, migration and invasiveness. It also increased resistance to chemotherapy through the regulation of ZNRF3, and suggested novel potential therapeutic targets for the treatment of osteosarcoma.

High-mobility group nucleosome-binding domain 5 increases drug resistance in osteosarcoma through upregulating autophagy

Although tumor therapy has been improved in the past decades, the survival outcomes for osteosarcoma remain unsatisfactory, and one of the primary reasons for the failure of current treatment is that patients with late-stage cancer often develop resistance to anticancer drugs. High-mobility group nucleosome-binding domain 5 (HMGN5) is a newly identified gene associated with cancer and autophagy, which could inhibit apoptosis induced by anticancer agents. However, it is still unclear whether HMGN5 regulated autophagy in osteosarcoma, and the mechanism and significance of HMGN5-mediated autophagy in tumor therapy is never investigated. In this study, we first detected HMGN5 in vivo and in vitro. HMGN5 was highly expressed in osteosarcoma tumor, especially in posttreatment tumor. Next, we employed adenovirus-mediated overexpression of HMGN5 in U-2OS and MG63 to investigate the role of HMGN5 in osteosarcoma cell lines. Adenovirus-mediated overexpression of HMGN5 could efficiently upregulate the expression level of HMGN5 in osteosarcoma cell lines at both messenger RNA (mRNA) and protein levels. Anticancer agents namely doxorubicin, cisplatin, and methotrexate each induced HMGN5 upregulation in human U-2OS and MG63 osteosarcoma cell lines. In addition, overexpression of HMGN5 reduced the chemosensitivity of osteosarcoma cells in vitro, and the mechanistic investigation revealed that HMGN5 increased drug resistance by upregulating autophagy. Therefore, HMGN5 is a critical factor in the development of chemoresistance through regulating autophagy, and it offers a novel target for improving osteosarcoma therapy.

Knockdown of TNFAIP1 inhibits growth and induces apoptosis in osteosarcoma cells through inhibition of the nuclear factor-κB pathway

Tumor necrosis factor-α-inducible protein-1 (TNFAIP1) plays a role in DNA synthesis, DNA repair, cell apoptosis and human diseases including cancer, and may be involved in tumor progression and metastases. However, little is known concerning the function of TNFAIP1 in human osteosarcoma (OS). The aim of the present study was to investigate the function and underlying mechanisms of TNFAIP1 in human OS. The expression of TNFAIP1 was examined by immunohistochemical assay using a tissue microarray procedure. A loss-of-function experiment was performed to explore the effects of lentiviral-mediated TNFAIP1 siRNA (siTNFAIP1) on cell proliferation, invasive potential and apoptosis by MTT and Transwell assays and flow cytometric analysis in OS (MG-63 and U-2 OS) cells. The results showed that the expression of TNFAIP1 protein was significantly increased in OS tissues compared with that in adjacent non-cancerous tissues (ANCTs) (73.3 vs. 48.9%, P=0.018), and was correlated with the distant metastasis of the patients with OS (P=0.029). Knockdown of TNFAIP1 suppressed cell proliferation and invasion, and induced cell apoptosis in the OS cells together with the downregulation of p65 nuclear factor-κB (NF-κB), proliferating cell nuclear antigen (PCNA) and matrix metalloproteinase-2 (MMP-2) and upregulation of caspase-3. Collectively, our findings indicate that high expression of TNFAIP1 is associated with distant metastasis of OS, and knockdown of TNFAIP1 inhibits the growth and invasion, and induces apoptosis in OS cells through inhibition of the NF-κB pathway, suggesting that TNFAIP1 may act as a potential therapeutic target for the treatment of cancer.

Surgical Therapy of Cervical Spine Fracture in Patients With Ankylosing Spondylitis

AbstractThe present study aimed to explore surgical treatments and assess the effects based on the features of cervical spine fracture in patients with ankylosing spondylitis (AS) and to summarize the experiences in perioperative management. Retrospective analysis was performed in 25 AS patients with cervical spine fracture treated in our hospital from January 2011 to December 2013. The patients were divided according to fracture segments, including 4 cases at C4 to C5, 8 cases at C5 to C6, and 13 cases at C6 to C7. Among them, 12 belonged to I type, 5 to II type, and 8 to III type based on the improved classification method for AS cervical spine fracture. The Subaxial Cervical Spine Injury Classification score for these patients was 7.2 ± 1.3, and the assessment of their neurological function states showed 6 patients (24%) were in American Spinal Injury Association (ASIA) A grade, 1 (4%) in ASIA B grade, 3 (12%) in ASIA C grade, 12 (48%) in ASIA D grade, and 3 (12%) in ASIA E grade. Surgical methods contained simple anterior approach alone, posterior approach alone, and combined posterior–anterior or anterior–posterior approach. The average duration of patients’ hospital stay was 38.6 ± 37.6, and the first surgical methods were as follows: anterior approach alone on 6 cases, posterior surgery alone on 9 cases, and combined posterior–anterior or anterior–posterior approach on 10 patients. The median segments of fixation and fusion were 4.1 ± 1.4 sections. Thirteen patients developed complications. During 2 to 36 months of postoperative follow-up, 1 patient died of respiratory failure caused by pulmonary infections 2 months after leaving hospital. At the end of the follow-up, bone graft fusion was achieved in the rest of patients, and obvious looseness or migration of internal fixation was not observed. In addition, the preoperative neurological injury in 12 patients (54.5%) was also alleviated in different levels. AS cervical spine fracture, an unstable fracture, should be treated with operation, and satisfactory effects will be achieved after the individualized surgical treatment according to the improved classification method for AS cervical spine fracture.

Potential prevention: Orally administered statins may retard the pathologic process of disc degeneration

Intervertebral disc (IVD) is the largest avascular tissue in the human, and disc degeneration is generally considered to result from chronic disc cell nutrition insufficiency. Responsible for making and maintaining the extracellular matrix, the cells of IVDs are supplied with essential nutrients by diffusion from the blood supply through mainly the cartilaginous endplates and the periphery of the annulus. Many researches have demonstrated a strong association between atherosclerosis and IVD degeneration. The plaques in the artery can disturb the blood supply to IVDs. In addition, local injection of simvastatin was preliminarily found to promote autogenous chondrogenic disc repair and retard disc degeneration. Herein we postulate that orally administered statins may not only improve nutrition supply of IVDs through decreasing the influence of plaques on disturbance of blood supply, but also may promote disc repair, which may provide an alternative strategy for disc repair in a less expensive and easily applied method.

Modified partial pedicle subtraction osteotomy for the correction of post-traumatic thoracolumbar kyphosis

BACKGROUND CONTEXT Pedicle subtraction osteotomy (PSO) is the most commonly recommended technique for the correction of local post-traumatic thoracolumbar deformity; however, the surgical results are not always satisfactory because the possibly damaged upper disc is preserved, and all the posterior elements are resected. PURPOSE The aim was to compare the results of standard PSO and modified PSO in the treatment of post-traumatic thoracolumbar kyphosis. STUDY DESIGN This was a retrospective multicenter comparative clinical study. PATIENT SAMPLE A total of 86 patients were included in the final analysis. OUTCOME MEASURES The outcome measures included local Cobb angle of the kyphosis, visual analog scale (VAS) score, and Oswestry disability index (ODI) score. METHODS The upper disc was resected, and the inferior wall of the index pedicle and the lower facet joint were preserved in the modified PSO. Patients with focal kyphosis greater than 30° who were treated with one-level osteotomy, without the presence of spine neoplasm, infection, or previous surgery, were included. The measurements included the VAS score, ODI score, and preoperative and postoperative Cobb angles. RESULTS Forty-two patients in the modified PSO group and 44 in the standard PSO group were included in the final analysis. The mean surgical time and blood loss were similar between the two groups. Both the VAS and ODI scores had improved significantly at the final follow-up in the two groups. The mean Cobb angle significantly improved from 39.6° to 5.6° in the modified PSO group and from 39.1° to 4.8° in the standard PSO group, with no significant difference between the two groups preoperatively or at the final follow-up. CONCLUSIONS The modified PSO provides an alternative method with which to correct kyphotic deformity in patients with post-traumatic thoracolumbar kyphosis.

Effect of dual screws across the vertebral neurocentral synchondrosis on spinal canal development in an immature spine: a porcine model.

BACKGROUND Questions remain as to the effect of pedicle screws on spinal canal development in young children. The purpose of this study was to determine the effects of unilateral placement of dual screws across the neurocentral synchondrosis on spinal canal development as assessed with histological analysis and measurement of the canal dimensions in an immature pig model. METHOD Twenty-seven one-month-old pigs were assigned to two groups on the basis of the surgical approach used to place unilateral double screws that did or did not cross the neurocentral synchondrosis. In one group, sixteen pigs underwent a posterior approach from T7 to T14 and were divided into four subgroups: no screws (without screw fixation), short screws (dual pedicle screws that did not cross the neurocentral synchondrosis), long screws (dual pedicle screws that crossed the neurocentral synchondrosis), and screw removal (long dual pedicle screws that were removed at six weeks postoperatively). In the other group, eleven pigs underwent an anterior approach, with double vertebral body screws placed via thoracotomy. These animals were divided into two subgroups: short screws (dual vertebral body screws that did not cross the neurocentral synchondrosis) and long screws (dual vertebral screws that crossed the neurocentral synchondrosis). All animals were killed at seventeen weeks. The total area, width, and depth of the spinal canal were measured on axial computed tomography (CT) images. Quantitative histological analysis was performed to measure the rate of neurocentral synchondrosis closure. RESULTS Use of unilateral double pedicle screws across the neurocentral synchondrosis through a posterior approach resulted in 97% neurocentral synchondrosis closure with a 20% decrease in the canal area and a 15% decrease in the canal depth. Use of unilateral double vertebral body screws across the neurocentral synchondrosis through an anterior approach resulted in 71% neurocentral synchondrosis closure with a 15% decrease in the canal area and an 8% decrease in the canal width. CONCLUSIONS Unilateral double pedicle screws crossing the neurocentral synchondrosis adversely affected spinal canal growth in immature pigs. CLINICAL RELEVANCE Pedicle screws should be used with caution in very young children, and a delay in surgical treatment until they are older should be considered.

A comparison of the Gallie technique and casting versus the harms technique for the treatment of odontoid fractures.

Objective: The objective of this study was to compare perioperative, clinical parameters, complications, and reoperation rate of the Gallie technique and head–neck–chest plaster with the Harms technique in the treatment of odontoid fractures. Design: A retrospective study. Setting: Level I spine center. Patients: Fifty-seven patients with odontoid fractures treated either with the Gallie technique and casting or the Harms technique between July 2002 and June 2008. Intervention: Surgery. Main Outcome Measurements: At a minimum of 2-year follow-up, comparison of the two groups was conducted in terms of hospital stay, blood loss, operation time, cost of the first admission, total cost, time to fusion, time to return to previous occupation, Japanese Orthopedic Association scores, visual analog scale scores of neck pain, complications (nonunion, delayed union, hardware breakage, wound infection), and reoperation rate. Results: There were no significant differences in terms of hospital stay, time to fusion, Japanese Orthopedic Association scores, neck pain visual analog scale scores, complications, or reoperation rate between the two groups. Blood loss, operation time, cost of the first admission, and total cost were significantly lower in the Gallie group than that in the Harms group. However, the Gallie group took longer to return to previous occupation than the Harms group (P < 0.001). Conclusions: Management of odontoid fractures by either the Gallie technique and casting or the Harms technique was found to be similar in clinical outcomes. Although the Harms technique was associated with more blood loss, operation time, and cost, the Harms technique was found to be superior to the Gallie technique with casting in terms of time to return to previous occupation.