Qingjun Ma

Simvastatin induces osteoblastic differentiation and inhibits adipocytic differentiation in mouse bone marrow stromal cells

To clarify the mechanism of the stimulatory effect of statins on bone formation, we investigated the effect of simvastatin, a widely used statin, on osteoblastic and adipocytic differentiation in primary cultured mouse bone marrow stromal cells (BMSCs). Simvastatin treatment enhanced the expression level of mRNA for osteocalcin and protein for osteocalcin and osteopontin, and increased alkaline phosphatase activity significantly (p<0.05). After BMSCs were exposed to an adipocyte differentiation agonist, Oil Red O staining, fluorescence activated cell sorting, and decreased expression level of lipoprotein lipase mRNA showed that treatment with simvastatin significantly inhibits adipocytic differentiation compared to controls that did not receive simvastatin (p<0.05). Lastly, we found that simvastatin induces high expression of BMP(2) in BMSCs. These observations suggested that simvastatin acts on BMSCs to enhance osteoblastic differentiation and inhibits adipocytic differentiation; this effect is at least partially mediated by inducing BMP(2) expression in BMSCs.

Cbfa1/osf2 Transduced Bone Marrow Stromal Cells Facilitate Bone Formation In Vitro and In Vivo

It has been well established that core binding factor a-1/osteoblast-specific factor-2 (cbfa1/osf2) is a key regulator of osteoblast differentiation and function, however, it is not known whether it can induce bone formation in vitro and in vivo. To investigate the effect of cbfa1/osf2 on bone formation, we used a recombinant adenoviral vector carrying the mouse cbfa1/osf2 gene to transduce primary cultured bone marrow stromal cells (MSCs) of BALB/c mice. We found that Ad-cbfa1/osf2-transduced MSCs produced cbfa1/osf2 protein and differentiated into osteoblast-like cells. The transduced MSCs had increased alkaline phosphatase activity, increased expression of osteocalcin, osteopontin and bone sialoprotein, and increased matrix mineralization in vitro. To observe the induction of bone formation in vivo, MSCs transduced with Ad-cbfa1/osf2 were transplanted into a 5 mm diameter critical-sized skull defect in BALB/c mice, with type I collagen as scaffolding material. Healing of the defect in treatment and control groups was examined grossly and histologically at four weeks. Skull defects transplanted with Ad-cbfa1/osf2-transduced MSCs had an average of 85% osseous closure at four weeks. Control groups in which the defects were not treated (group 1), treated with collagen only (group 2), or treated with collagen and nontransduced MSCs (group 3) showed little or no osseous healing. These studies indicate that cbfa1/osf2 can induce osteoblast differentiation and bone formation both in vitro and in vivo, suggesting that MSCs transduced with the cbfa1/osf2 gene may be useful in treating bone defects.

Interferon alfa-2b for recurrent and metastatic giant cell tumor of the spine: report of two cases.

Study Design. Case report. Objective. To demonstrate that interferon alfa-2b is a therapeutic option for obtaining long-term control of recurrent and metastatic giant cell tumor of spine. Summary of Background Data. Interferon alfa served as angiogenesis inhibitor and has been successfully used to treat giant cell tumor of long bones and facial bones. Up to date, no report is found with regard to the use of interferon as a stand-alone treatment for unresectable, recurrent, and metastatic giant cell tumor originated from the spine. Methods. A 29-year-old woman with C1 and C2 giant cell tumor was treated by radiotherapy, intralesional curet, and chemotherapy orderly. Tumor recurred after 2 years. A second curet was undertaken. Tumor recurred second time and caused severe spinal cord compression. Lung metastasis was diagnosed simultaneously. A 24-year-old man with recurrent giant cell tumor of T5 and T6 was treated by spondylectomy of T5 and T6. Six months later, a giant metastatic lesion was found in sacrococcygeal region, which was excised and proved to be giant cell tumor of bone. Four months later, 2 recurrent lesions were found beside the rectum. Interferon alfa-2b at a dose of 3,000,000 U/m2 was then administered subcutaneously everyday for both patients for 3.5 and 3 years, respectively. Results. No major complications related to the use of interferon occurred. The lesion in C1-C2 of the first patient regressed steadily and was restricted and encircled within the lateral mass. The metastatic lesions in the lungs also significantly reduced. The pararectal lesions of the second patient disappeared completely. Conclusion. Interferon therapy may be an effective and safe treatment for spine giant cell tumor recurrence and metastasis in soft tissue. The effectiveness may be time and dosage dependent.

Prognostic significance of downregulated expression of programmed cell death 5 in chondrosarcoma.

Programmed Cell Death 5 (PDCD5) is a novel apoptosis‐related gene and deregulation of PDCD5 is involved in tumorigenicity. This study was designed to investigate the expression level of PDCD5 and to clarify its clinical significance in chondrosarcoma.

Increased levels of hypoxia-inducible factor-1α are associated with Bcl-xL expression, tumor apoptosis, and clinical outcome in chondrosarcoma

Hypoxia‐inducible factor (HIF)‐1α is a key nuclear transcription factor that regulates the cellular response to hypoxia, and is important for solid tumor growth and survival. However, the underlying role of HIF‐1α in human chondrosarcoma has not been well characterized. This study aims to investigate the expression patterns of HIF‐1α in chondrosarcoma, and its association with clinicopathologic features, Bcl‐xL expression, apoptosis index (AI), and overall survival of patients with chondrosarcoma. Our results shown that the protein levels of HIF‐1α were increased, and the mRNA and protein levels of Bcl‐xL were also increased in SW1353 cells under hypoxic conditions. In eight patients with chondrosarcoma, increased expression of HIF‐1α and Bcl‐xL was detected in chondrosarcoma tissues compared with the paired adjacent normal tissues. Of 34 archival specimens of chondrosarcomas, 20 (58.8%) showed high HIF‐1α protein expression as compared to benign cartilage tumors. Increased HIF‐1α expression was correlated with a higher pathological grade and MSTS stage of chondrosarcoma. Moreover, HIF‐1α expression was significantly associated with Bcl‐xL expression and AI. More significantly, the survival rate of patients with HIF‐1α high tumors was significantly lower than that of patients with HIF‐1α low tumors. These findings suggest that increased HIF‐1α levels mediated up‐regulation of Bcl‐xL play a prominent role in evasion of apoptosis and tumor progression, and can be predictive for the prognosis in human chondrosarcoma.

Differential proteomic profiling of chordomas and analysis of prognostic factors

The recurrence rate of chordoma is high, and the prognosis is poor.

Association of elevated HIF-2α levels with low Beclin 1 expression and poor prognosis in patients with chondrosarcoma.

BackgroundHypoxia inducible factor (HIF)-2α is an important transcription factor that contributes to tumor proliferation and progression. Beclin 1 is a key mediator of autophagy, and dysfunction of Beclin 1 is implicated in tumorigenicity. This study was designed to investigate the expression patterns of HIF-2α and Beclin 1 and to clarify their clinical significance in chondrosarcoma.MethodsThe mRNA and protein levels of HIF-2α and Beclin 1 in chondrosarcoma and the corresponding nontumor tissues were analyzed by real-time polymerase chain reaction and Western blot, respectively. The protein expression of HIF-2α and Beclin 1 was investigated by immunohistochemistry, and their associations with clinicopathological factors and overall survival were evaluated.ResultsHIF-2α was remarkably elevated, whereas Beclin 1 was significantly reduced in chondrosarcoma compared with the corresponding nontumor tissues. High HIF-2α level and negative Beclin 1 expression were 52.9% and 58.8% in chondrosarcoma specimens, respectively. HIF-2α and Beclin 1 were associated with histological grade and Musculoskeletal Tumor Society stage. There was a significant inverse relationship between HIF-2α and Beclin 1. HIF-2α and Beclin 1 had significant impacts on the prognosis of chondrosarcoma patients. Multivariate analysis revealed that Beclin 1 was an independent prognostic factor for overall survival of patients with chondrosarcoma.ConclusionsElevated HIF-2α levels assocaited with low Beclin 1 expression play a role in the development of chondrosarcoma. Beclin 1 can serve as a novel biomarker to predict survival of chondrosarcoma patients, and may represent a potential therapeutic target.

Simvastatin induces estrogen receptor-alpha (ER-α) in murine bone marrow stromal cells

Simvastatin has been shown to stimulate osteogenesis both in vitro and in vivo. However, the mechanism by which simvastatin exerts its effects is still unclear. We previously reported that simvastatin promotes bone morphogenetic protein 2 (BMP-2) expression, induces osteoblastic differentiation, and inhibits adipocytic differentiation in mouse bone marrow stromal cells (BMSCs), and that this occurs, at least in part, via a BMP-2-dependent pathway. The aim of this study was to investigate further the mechanisms by which simvastatin stimulates osteogenesis in mouse BMSCs. To determine whether simvastatin-mediated osteogenesis was dependent on BMP-2, mouse BMSCs were treated with nonimmune normal mouse IgG or BMP-2 neutralizing antibodies combined with different concentrations of simvastatin. Surprisingly, the stimulatory effect of simvastatin on alkaline phosphatase (ALP) activity was not completely blocked by neutralizing BMP-2 monoclonal antibody treatment. Interestingly, we found that estrogen receptor-alpha (ER-α) protein levels increased after mouse BMSCs were treated with simvastatin for 72 h in a concentration-dependent manner. Moreover, the stimulatory effect of simvastatin on ALP activity in BMSCs was blocked by the estrogen receptor agonist ICI 182,780, and cotreatment with 17-β-estradiol and simvastatin increased ALP activities by two-to threefold in the BMSCs compared with treatment with simvastatin alone. These results suggest that simvastatin-induced in vitro osteogenesis in mouse BMSCs is mediated, at least in part, by induction of ER-α and not by BMP-2 alone. These results provide new insight into the mechanisms of simvastatin-induced bone formation in BMSCs.

Reduced expression of von Hippel-Lindau protein correlates with decreased apoptosis and high chondrosarcoma grade.

BACKGROUND Mutations and loss of the von Hippel-Lindau (VHL) tumor suppressor gene are associated with most renal cancers as well as several other types of human tumors, but the potential role of the VHL protein (pVHL) in patients with chondrosarcoma has not been characterized. The purpose of the present study was to investigate the expression profiles of pVHL in chondrosarcoma and its association with clinicopathologic parameters, Bax expression, the apoptosis index, and overall survival of patients with chondrosarcoma. METHODS The messenger RNA (mRNA) and protein levels of VHL in fresh specimens from eight chondrosarcomas were studied with use of real-time polymerase chain reaction and Western blot, respectively. The protein expression of VHL and Bax was investigated by means of immunohistochemical analysis of paraffin-embedded clinical specimens from seventeen benign cartilage tumors and thirty-four chondrosarcomas. The apoptosis index in chondrosarcoma was examined by means of the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) assay. Curves for overall survival were drawn according to the Kaplan-Meier method, and differences were analyzed with the log-rank test. The association of pVHL expression with the clinicopathologic parameters, Bax expression, apoptosis index, and overall survival for patients with chondrosarcoma was also analyzed. RESULTS Levels of VHL protein (p = 0.005) and mRNA (p = 0.008) were significantly reduced in chondrosarcoma tissues as compared with the paired adjacent normal tissues. Immunohistochemical analysis showed decreased pVHL in a significantly higher proportion of chondrosarcomas (64.7%) than benign cartilage tumors (29.4%). pVHL expression was positively correlated with Bax expression and the apoptosis index in chondrosarcoma. Longitudinal studies of a cohort of patients with chondrosarcomas showed that decreased pVHL expression significantly correlated with increased tumor grade (p = 0.026) but was not independently predictive of overall survival. CONCLUSIONS Reduced pVHL expression was associated with decreased apoptosis and increasing chondrosarcoma grade, but the relationship between these findings and chondrosarcoma pathogenesis requires further study.

Cervical Chordoma in Childhood Without Typical Vertebral Bony Destruction: Case Report and Review of the Literature

Study Design. Case report. Objective. We present a giant cervical chordoma without typical vertebral bony destruction in an 11-year-old girl. Summary of Background Data. Chordomas are rare malignant bone tumors that arise at both the cranial and the caudal ends of the axial skeleton, characteristically destroying the bone. Cervical chordomas comprise only 3% to 7% of all chordomas. To our knowledge, there is no case of cervical chordoma in a child, presenting without vertebral body involvement, in English literature. Methods. Discussion on the patient’s clinical, radiologic history, and histopathologic diagnosis of the resected tumor, with a review of the relevant background literature. Results. We report the first case of cervical chordoma in a child without typical vertebral bony destruction, the diagnosis of which was difficult to confirm before and after operation. Conclusion. Giant notochordal rest and benign notochordal cell tumors (BNCTs) need to be recognized for differential diagnosis of this atypical chordoma. A long-term follow-up might be necessary for the diagnosis of this nontypical patient.