Macrophage infiltration predicts a poor prognosis for human ewing sarcoma.

Ewing sarcoma-primitive neuroectodermal tumor (EWS) is associated with the most unfavorable prognosis of all primary musculoskeletal tumors. The objective of the present study was to investigate whether tumor-associated macrophages (TAMs) affect the development of EWS. TAMs were isolated from mouse xenografts using CD11b magnetic beads and examined for their cytokine expression and osteoclastic differentiation. To evaluate the role of TAMs in xenograft formation, liposome-encapsulated clodronate was used to deplete TAMs in mice. Macrophage infiltration and tumor microvascular density were histologically evaluated in 41 patients with EWS, and association with prognosis was examined using Kaplan-Meier survival analysis. In mouse EWS xenografts, TAMs expressed higher concentrations of cytokines including interleukin-6, keratinocyte-derived chemokine, and monocyte chemotactic protein-1. TAMs were more capable than normal monocytes of differentiating into tartrate-resistant acid phosphatase-positive giant cells. Depleting macrophages using liposome-encapsulated clodronate significantly inhibited development of EWS xenografts. In human EWS samples, higher levels of CD68-positive macrophages were associated with poorer overall survival. In addition, enhanced vascularity, increase in the amount of C-reactive protein, and higher white blood cell counts were also associated with poor prognosis and macrophage infiltration. TAMs seem to enhance the progression of EWS by stimulating both angiogenesis and osteoclastogenesis. Further investigation of the behavior of TAMs may lead to development of biologically targeted therapies for EWS.

Inhibition of the transcriptional function of p53 by EWS-Fli1 chimeric protein in Ewing Family Tumors.

The chromosomal translocation t(11;22)(q24;q12) generates the EWS-Fli1 fusion gene, which contributes to the development of Ewing Family Tumors (EFTs). Although p53 mutations are found only in 5-20% of EFTs, the p53 pathway is thought to be abrogated in EFTs. The role of EWS-Fli1 in the p53 pathway in the tumor is still poorly understood. In this study, using immunoprecipitation and co-localization, we show that EWS-Fli1 interacts with p53 within the nucleus in vivo. The introduction of EWS-Fli1 resulted in significant reduction of promoter activities and mRNA levels of p21 and mdm2, meanwhile it canceled p53-dependent growth suppression. In contrast, knockdown of EWS-Fli1 expression mediated by small interfering RNAs (siRNA) also augmented the induction of p21 and mdm2 in response to DNA damage. Furthermore, using serial deletion constructs of the EWS-Fli1 fusion protein, we determined that EWS-Fli1 binding to p53 as well as inhibition of p21 and mdm2 promoter activities was mediated by its N-terminal domain (amino acid residues 65-109). These observations suggest that the N-terminal region of EWS-Fli1 might associate with p53 and impair its transcriptional activity, subsequently inhibiting the expression of its downstream genes. These results might provide new insight into the oncogenesis of EFTs by EWS-Fli1 via the inhibition of p53 function.

Suberoylanilide hydroxamic acid (SAHA) induces apoptosis or autophagy-associated cell death in chondrosarcoma cell lines.

BACKGROUND: Since chondrosarcoma has a high resistance to conventional chemotherapy and radiotherapy, surgical resection is currently the only effective treatment. Histone deacetylase (HDAC) inhibitor exert anticancer effects, but have not been tested in chondrosarcoma. MATERIALS AND METHODS: We investigated the phenotypic change in chondrosarcoma cells treated with SAHA by cell viability assay, Western blot, flow cytometric analysis and electron microscopy. RESULTS: SAHA inhibited the growth of chondrosarcoma cell lines and induced apoptosis in SW1353 with a cleaved-PARP expression and sub-G1 fragmentation according to flow cytometric analysis. On the other hand, in RCS and OUMS-27, SAHA induced autophagy-associated cell death as shown by the detection of autophagosome-specific protein and specific ultrastructural morphology in the cytoplasm. In addition, SAHA significantly inhibited tumor growth in an in vivo xenograft model. CONCLUSION: These results suggest that SAHA might be a promising agent for performing clinically useful chemotherapy against chondrosarcomas.

Cyclin-dependent kinase inhibitor, flavopiridol, induces apoptosis and inhibits tumor growth in drug-resistant osteosarcoma and Ewing's family tumor cells.

Multimodal therapies play important roles in the treatment of osteosarcoma (OS) and Ewing's family of tumors (EFTs), two most frequent malignant bone tumors. Although the clinical outcome of primary OS and EFTs is greatly improved, the relapsed cases often are associated with multidrug resistance of the tumors and the prognosis of these patients is still poor. Flavopiridol, a pan cyclin-dependent kinase (CDK) inhibitor is a novel antitumor agent that can induce cell cycle arrest and apoptosis in many cancer cells. However, there have been no studies about the effects of flavopiridol on drug-resistant OS and EFTs. Here, we demonstrated that flavopiridol induced the cleavage of poly-ADP-ribose polymerase (PARP) in a time and dose dependent manner in adriamycin-resistant OS and EFTs cells expressing P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP(1)) as effectively as in their parental cells. Our data also showed that flavopiridol caused the release of mitochondrial cytochrome c and the activation of caspase-9, caspase-8 and caspase-3, with an increase ratio of the proapoptotic protein level (Bax) to the antiapoptotic protein level (Bcl-2 and Bcl-X(L)), while apoptosis was inhibited by pan caspase inhibitor (Z-VAD-FMK) and caspase-3 inhibitor (Z-DEVD-FMK), not by caspase-8 inhibitor (Z-IETD-FMK). The treatment with flavopiridol further inhibited the tumor growth in mouse models of the drug-resistant OS and EFTs. These results suggest that flavopiridol might be promising in clinical therapy for the relapsed OS and EFTs.

Effects of the Second National Acute Spinal Cord Injury Study of high-dose methylprednisolone therapy on acute cervical spinal cord injury-results in spinal injuries center.

STUDY DESIGN: Retrospective single-center study. OBJECTIVE: To evaluate the recovery of motor function and the early complications in patients with acute cervical spinal cord injury after receiving a high dose of methylprednisolone sodium succinate (MPSS) within 8 hours of injury. SUMMARY OF BACKGROUND DATA: High-dose MPSS therapy has been demonstrated to improve the neurologic recovery in patients with acute spinal cord injury. However, it remains a controversial treatment. METHODS: Seventy patients were included in this study: 37 in the MPSS group who were treated with MPSS within 8 hours of their injury according to the Second National Acute Spinal Cord Injury Study protocol, and 33 in non-MPSS group who were not administered with MPSS. Improvements in the American Spinal Injury Association motor score were compared between the MPSS group and the non-MPSS group. In patients with complete motor loss at admission and follow-up periods, improvements of myotomal levels between the MPSS (n = 15) and non-MPSS groups (n = 21) were compared. Early complications within 6 weeks of high-dose MPSS therapy were compared with those of no MPSS therapy. RESULTS: Among the patients with incomplete paralysis at admission, the American Spinal Injury Association motor scores in the MPSS group were improved more significantly than those in the non-MPSS group at 6 weeks and 6 months after injury. Meanwhile, among the patients with complete paralysis at admission, the patients in the MPSS group did not show significantly more change in motor score than those in the non-MPSS group. Improvement in myotomal level had no significant difference between the MPSS and non-MPSS groups. The MPSS group had 10 patients with early complications, while the non-MPSS group had 14. The differences between the 2 groups showed no statistical significance. CONCLUSIONS: MPSS should be administered to patients with incomplete cervical spinal cord injury according to the Second National Acute Spinal Cord Injury Study protocol.