Gang Han

C-Myc overexpression promotes osteosarcoma cell invasion via activation of MEK-ERK pathway.

Osteosarcoma is a highly metastatic malignancy often with poor prognosis. c-Myc amplification is implicated in osteosarcoma pathogenesis. However, the role of c-myc overexpression in osteosarcoma cell invasion remains unexplored. This study showed that c-myc overexpression enhanced MG-63 and SAOS-2 osteosarcoma cell invasion. Treatment of MEK inhibitor PD98059 or PI3K inhibitor LY294002 decreased cell invasion along with downregulation of MMP-2 and MMP-9 expression. c-Myc overexpression stimulated MEK-ERK pathway whereas inhibited the activity of PI3K-AKT pathway. Specifically, inhibition of MEK-ERK pathway by PD98509 blocked the enhancement effect on cell invasion as well as MMP-2 and MMP-9 expression. The present study demonstrates that c-myc overexpression promotes osteosarcoma cell invasion, probably via activation of MEK-ERK pathway.

MicroRNA-124 functions as a tumor suppressor and indicates prognosis in human osteosarcoma

MicroRNA-124 (miR-124) has been demonstrated to be downregulated in numerous human malignancies and correlated with tumor progression. However, its expression and clinical significance in osteosarcoma remains unclear. Thus, the aim of the present study was to explore the effects of miR-124 in osteosarcoma tumorigenesis and development. Using reverse transcription-quantitative polymerase chain reaction, miR-124 expression was detected in primary osteosarcoma tissues and osteosarcoma cell lines. The correlation of miR-124 expression with clinicopathological factors and prognosis was statistically analyzed. MTT, flow cytometric, and Transwell invasion and migration assays were used to test the proliferation, apoptosis, invasion and migration of osteosarcoma cells transfected with miR-124 mimic. It was found that the expression levels of miR-124 in osteosarcoma tissues were significantly lower than those in corresponding noncancerous bone tissues (P<0.001). In addition, miR-124 downregulation more frequently occurred in osteosarcoma specimens with advanced clinical stage (P<0.001), positive distant metastasis (P=0.005) and poor response to neoadjuvant chemotherapy (P=0.013). Univariate and multivariate analysis identified low miR-124 expression as an unfavorable prognostic factor for overall survival. Furthermore, transfection of miR-124 mimic into MG63 cells was able to reduce cell proliferation, invasion and migration, and promote cell apoptosis. These findings indicate that miR-124 may act not only as a novel diagnostic and prognostic marker, but also as a potential target for the molecular therapy of osteosarcoma.

Hippo/YAP signaling pathway is involved in osteosarcoma chemoresistance

BackgroundOsteosarcoma is the most common bone malignancy in children and adolescents, and 20%–30% of the patients suffer from poor prognosis because of individual chemoresistance. The Hippo/yes-associated protein (YAP) signaling pathway has been shown to play a role in tumor chemoresistance, but no previous report has focused on its involvement in osteosarcoma chemoresistance. This study aimed to investigate the role of the Hippo/YAP signaling pathway in osteosarcoma chemoresistance and to determine potential treatment targets.MethodsUsing the Cell Titer-Glo Luminescent cell viability assay and flow cytometry analysis, we determined the proliferation and chemosensitivity of YAP-overexpressing and YAP-knockdown osteosarcoma cells. In addition, using western blotting and the real-time polymerase chain reaction technique, we investigated the alteration of the Hippo/YAP signaling pathway in osteosarcoma cells treated with chemotherapeutic agents.ResultsMammalian sterile 20-like kinase 1 (MST1) degradation was increased, and large tumor suppressor kinase 1/2 (LATS1/2) total protein levels were decreased by methotrexate and doxorubicin, which increased activation and nuclear translocation of YAP. Moreover, YAP increased the proliferation and chemoresistance of MG63 cells.ConclusionsThe Hippo/YAP signaling pathway plays a role in osteosarcoma chemoresistance, and YAP is a potential target for reducing chemoresistance.

IL-17A stimulates the progression of giant cell tumors of bone.

Purpose: Giant cell tumors of bone (GCTB) exhibit aggressive bone lytic behavior. Studies have shown that interleukin 17A (IL-17A) is involved pathologic bone resorption in various skeletal disorders. Thus, we have investigated the role of IL-17A in GCTBs. Experimental Design: We evaluated the progression of GCTBs using Campanacci grading and Enneking staging systems in 74 patients with GCTB. The expression of IL-17A and the IL-17A receptor A (IL-17RA) was assessed in GCTB tissues and in both multinucleated giant cells (MNGC) and stromal cells cultured in vitro using immunostaining and reverse transcription PCR (RT-PCR). The effects of IL-17A on the osteolytic activity of the MNGCs and the proliferation of the stromal cells were investigated using the “pit” formation and MTT assays, respectively. The effects of IL-17A on the expression of proosteolytic factors were examined in primary cultured MNGCs and stromal cells using RT-PCR, Western blotting, and gene expression microarrays. Results: In GCTBs, we detected abundant levels of IL-17A, which were associated with tumor extension and grade. IL-17A is predominantly produced by MNGCs, whereas IL-17RA is expressed by both MNGCs and stromal cells in GCTBs. In the MNGCs, the IL-17A increased the mRNA expression of IL-17A and proosteolytic enzymes, and also enhanced osteolytic ability. In the stromal cells, the IL-17A stimulated cellular proliferation and the expression of proosteolytic factors, including RANKL through myc and STAT3, respectively. In addition, IL-17A stimulated in vivo tumor growth and the extent of angiogenesis in GCTBs. Conclusion: IL-17A stimulates the progression of GCTBs and might represent a useful candidate marker for progression and as a therapeutic target for GCTBs. Clin Cancer Res; 19(17); 4697–705. ©2013 AACR.

Reconstruction using massive allografts after resection of extremity osteosarcomas the study design: A retrospective cohort study

PURPOSE Allografts have been shown useful in the reconstruction of bone defects after tumor resection. This study aimed to investigate the feasibility of using massive allografts to reconstruct bone defects after resection of extremity osteosarcomas. METHODS The clinical data of 15 patients treated with massive allograft reconstruction after resection of extremity osteosarcomas from January 2005 to January 2008 were retrospectively reviewed. Neoadjuvant and postoperative chemotherapy was used in all patients. The postoperative functions of the salvaged limbs were evaluated using the scoring system proposed by the Musculoskeletal Tumor Society (MSTS). RESULTS All patients were followed up for a mean of 61 months (range, 14-99 months). No nonunion occurred during follow-up. The mean time to union was 9 months (range, 3-21 months). No immune rejection, allograft infection, allograft fracture, and limb length disparity occurred. However, 2 patients had broken implants. The mean MSTS score at the last follow-up was 26 points. Four patients died and 2 patients had tumor recurrence. The 5-year disease free survival rate was 73.3%. CONCLUSION Massive allograft reconstruction is safe and effective for bone defects caused by resection of extremity osteosarcomas.

Study on the Health-related Quality of Life in Patients after Surgery for Malignant Bone Tumors

AIM We conducted a study in China to assess the health-related quality of life (HRQoL) in patients treated on for malignant bone tumors after surgery, and investigate the possible determinants. METHODS The subjects were 120 patients surgically treated by amputation and limb-salvage for bone tumors during the period of June 2008 to June 2010. The Medical Outcomes Study Short Form 36 (SF-36) was employed to measure the HRQoL of all the patients before and after surgery. RESULTS With regard to the results of the general quality of life tool (SF-36), we observed a significant improvement of all the indexes of HRQoL after 6 months (p<0.05). PF, RP and BP scores showed significant increase between surgery after 6 and 12 months (p<0.05). The means of the HRQoL of bone tumor patients in our study were still much lower than those of general population in every domain, even 12 months after surgery. Logistic regression showed that female patients were found to have lower scores in physical component summary (PCS) than males (OR=0.64, 95% CI=0.35-0.89). Patients older than 15 years had lower scores in mental component summary (MCS) (OR=0.60, 95% CI=0.32-0.86). Ablative surgery was related to both lower MCS and PCS scores (For MCS, OR=0.54, 95% CI=0.31-0.83; for PCS, OR=0.43, 95% CI=0.25-0.73). CONCLUSION Our study showed the treatment for bone tumor could greatly alter the HRQoL of patients. Age, sex and type of surgery were associated with physical or mental HRQoL after surgery.

Survival and prognostic factors in Chinese patients with osteosarcoma: 13-year experience in 365 patients treated at a single institution

This study was designed to retrospectively analyze the survival and prognostic factors in Chinese osteosarcoma patients received neoadjuvant chemotherapy or/and surgery in a single institution. A total of 365 patients with pathological proved osteosarcoma undergoing neoadjuvant chemotherapy or/and surgery in a single institution between December 1999 and December 2012 were retrospectively analyzed for the demographic, tumor-related, and treatment-related variables, prognostic factors for survival rate and chemotherapy response. There were 231 males and 134 females (ratio, 1.72:1). The average age was 21±10years, with peak age between 10 and 20 years old (62%, 226/365). Of 365 patients, 319 (87.4%) suffered from primary tumor only, and 46 (12.6%) had metastases upon initial presentation. The overall 5-year survival rate was 65%. Upon univariate analysis, tumor site (femur 60.3%; other long bone 70.2%; trunk 33.6%; P=0.012), primary metastases (yes 36.7%; no 68.9%; P=0.000), tumor response to preoperative chemotherapy (good 89.8%; poor 47.5%; P=0.001) and recurrence/metastases after treatment (yes 36.2%; no 63.8%; P=0.000) were associated with higher 5-year survival rate. All factors except tumor site maintained their significance in multivariate testing. Male sex and nonconventional subtype of tumor were related to a higher likelihood of poor chemotherapy response.The absence of metastases at initial presentation, negative local recurrence or metastases after treatment, and tumor response to chemotherapy are of independent prognostic value in osteosarcoma. The overall prognostic factors and survival in Chinese patients are similar to those patients reported in western countries.

Osteosarcoma around the knee treated with neoadjuvant chemotherapy and a custom-designed prosthesis.

This article describes a novel approach using high-dose neoadjuvant chemotherapy with wide tissue resection and a specially designed artificial joint in 104 patients with stage IIB osteosarcoma near the knee. Sixty-four lesions were located at the distal femur, 39 at the proximal tibia, and 1 invaded the proximal tibia from the distal femur. Pathological fracture was present in 9 patients. Three courses of high-dose methotrexate, doxorubicin, and ifosfamide were administered preoperatively, and 6 courses were administered postoperatively. Preoperative radiographs and magnetic resonance images were obtained to determine the required tumor resection range and prosthesis size. Osteotomy of 3 cm of normal bone outside the tumor and wide resection of normal peripheral soft tissue were performed. Reconstruction with a rotary hinge or simple hinge prosthesis, as appropriate, was then performed. The Musculoskeletal Tumor Society 93 scoring system was used to evaluate limb function 6 months postoperatively. At final follow-up, recurrence, complication, survival, and amputation rates were 4%, 18%, 85%, and 4%, respectively. No recurrences were observed at the ends of amputated bones. Complications included infection (6%), nerve injury (3%), and prosthesis-related events (2% dislocation, 3% breakage, and 1% dislocation-related). Mean Musculoskeletal Tumor Society 93 score was 28 points, which indicated an excellent functional outcome. The low recurrence rate is attributed to the efficacy of the chemotherapy and the accuracy of the margin of resection.Effective chemotherapy reduces the risk of tumor metastasis and clarifies the tumor margin. Accurate identification of the resection margin reduces the risk of local recurrence.

Pelvic reconstruction with allogeneic bone graft after tumor resection

OBJECTIVES : Pelvic reconstruction after tumor resection is challenging. METHODS: A retrospective study had been preformed to compare the outcomes among patients who received pelvic reconstructive surgery with allogeneic bone graft after en bloc resection of pelvic tumors and patients who received en bloc resection only. RESULTS: Patients without reconstruction had significantly lower functional scores at 3 months (10 vs. 15, P = 0.001) and 6 months after surgery (18.5 vs. 22, P = 0.0024), a shorter duration of hospitalization (16 day vs. 40 days, P < 0.001), and lower hospitalization costs (97,500 vs. 193,000 RMB, P < 0.001) than those who received pelvic reconstruction. Functional scores were similar at 12 months after surgery (21.5 vs. 23, P = 0.365) with no difference in the rate of complications between the two groups (P > 0.05). CONCLUSIONS : Pelvic reconstruction with allogeneic bone graft after surgical management of pelvic tumors is associated with satisfactory surgical and functional outcomes. Further clinical studies are required to explore how to select the best reconstruction method. Level of Evidence IV, Case Series.