Local and systemic control for osteosarcoma of the extremity treated with neoadjuvant chemotherapy and limb salvage surgery: the Rizzoli experience

Identification of mitochondrial-related signature and molecular subtype for the prognosis of osteosarcoma

Mitochondria play a vital role in osteosarcoma. Therefore, the purpose of this study was to investigate the potential role of mitochondrial-related genes (MRGs) in osteosarcoma. Based on 92 differentially expressed MRGs, osteosarcoma samples were divided into two subtypes using the nonnegative matrix factorization (NMF). Ultimately, a univariate, least absolute shrinkage and selection operator (LASSO), and multivariate Cox analysis were performed to construct a prognostic risk model. The single-sample gene set enrichment analysis assessed the immune infiltration characteristics of osteosarcoma patients. Finally, we identified an osteosarcoma biomarker, malonyl-CoA decarboxylase (MLYCD), which showed downregulation. Osteosarcoma cells proliferation, migration, and invasion were effectively inhibited by the overexpression of MLYCD. Our findings will help us to further understand the molecular mechanisms of osteosarcoma and contribute to the discovery of new diagnostic biomarkers and therapeutic targets.

Transcriptional activators YAP/TAZ and AXL orchestrate dedifferentiation, cell fate, and metastasis in human osteosarcoma

Osteosarcoma (OS) is a molecularly heterogeneous, aggressive, poorly differentiated pediatric bone cancer that frequently spreads to the lung. Relatively little is known about phenotypic and epigenetic changes that promote lung metastases. To identify key drivers of metastasis, we studied human CCH-OS-D OS cells within a previously described rat acellular lung (ACL) model that preserves the native lung architecture, extracellular matrix, and capillary network. This system identified a subset of cells—termed derived circulating tumor cells (dCTCs)—that can migrate, intravasate, and spread within a bioreactor-perfused capillary network. Remarkably, dCTCs highly expressed epithelial-to-mesenchymal transition (EMT)-associated transcription factors (EMT-TFs), such as ZEB1, TWIST, and SOX9, which suggests that they undergo cellular reprogramming toward a less differentiated state by coopting the same epigenetic machinery used by carcinomas. Since YAP/TAZ and AXL tightly regulate the fate and plasticity of normal mesenchymal cells in response to microenvironmental cues, we explored whether these proteins contributed to OS metastatic potential using an isogenic pair of human OS cell lines that differ in AXL expression. We show that AXL inhibition significantly reduced the number of MG63.2 pulmonary metastases in murine models. Collectively, we present a laboratory-based method to detect and characterize a pure population of dCTCs, which provides a unique opportunity to study how OS cell fate and differentiation contributes to metastatic potential. Though the important step of clinical validation remains, our identification of AXL, ZEB1, and TWIST upregulation raises the tantalizing prospect that EMT-TF-directed therapies might expand the arsenal of therapies used to combat advanced-stage OS.

BMP-2 and miR-29c in osteosarcoma tissues on proliferation and invasion of osteosarcoma cells

Expression of bone morphogenetic protein (BMP)-2 and microRNA (miR)-29c in osteosarcoma tissues and effects on proliferation and invasion of osteosarcoma cells were investigated. A retrospective analysis of 75 patients with osteosarcoma who underwent surgery in Tianjin Baodi Hospital from May 2013 to June 2017 was conducted. A total of 75 osteosarcoma tissues and 51 normal paraneoplastic tissues were collected. RT-PCR was used to compare the expression difference of BMP-2 and miR-29c. miR-29c mimics (experimental group A) and BMP-2 siRNA plasmid (experimental group B) were transfected into human osteosarcoma cells MG-63, respectively. The transfected cells were divided into miRNA negative control (miR-NC) group (cells transfected with miR-negative control), siRNA negative control group (cells transfected with non-silent siRNA) and blank group (cells without any transfection). MTT assay was used to detect cell proliferation in each group at different time periods. Transwell insert was used to detect invasion of cells in vitro. The relative expression of BMP-2 in osteosarcoma tissue was significantly higher than that in paraneoplastic tissue (P<0.05). Τhe relative expression of miR-29c in osteosarcoma tissue was significantly lower than that in paraneoplastic tissue (P<0.05). The cell survival rates in experimental groups A and B were significantly lower than those in the blank, miR-NC negative control and siRNA negative control groups on day 5 (P<0.05). The number of cell transmembranes in experimental groups A and B was significantly lower than those in the blank, miR-NC negative control and siRNA negative control groups (P<0.05). BMP-2 is over-expressed in osteosarcoma tissues, and miR-29c is under-expressed in osteosarcoma tissues. Interfering with the expression of BMP-2 and overexpression of miR-29c can inhibit the proliferation and invasion of osteosarcoma cells, indicating that BMP-2 and miR-29c may be involved in the regulation of proliferation and metastasis of osteosarcoma cells and could be used as new molecular target markers for the diagnosis and treatment of osteosarcoma.

Neoadjuvant chemotherapy combined with limb salvage surgery in patients with limb osteosarcoma of Enneking stage II: a retrospective study

Objective

To explore the effect of neoadjuvant chemotherapy combined with limb salvage surgery in patients with limb osteosarcoma of Enneking stage II.

Patients and methods

Medical records of 98 patients who met the inclusion criteria were retrospectively analyzed. Of these patients, 56 cases who received neoadjuvant chemotherapy combined with limb salvage surgery were listed as group A, while another 42 patients who received limb salvage surgery combined with adjuvant chemotherapy were listed as group B. The recurrence and metastasis rate, survival rate, limb function and incidence of adverse reactions were compared between the two groups.

Results

All 98 patients completed the treatment in this study. Baseline characteristics showed no significant differences between group A and group B, including age, gender, tumor location, maximum tumor diameter and Enneking stage (all P>0.05). The total metastasis and recurrence rate of group A was significantly lower than that of group B (25.0% vs 47.6%, χ²=5.419, P=0.020). The Kaplan–Meier method showed that progression-free survival (PFS) (log-rank χ²=4.014, P=0.045) and overall survival (OS) (log-rank χ²=3.859, P=0.049) of group A were both significantly higher than those of group B. There was no significant difference in the incidence of grades III–IV adverse reactions between the two groups (all P>0.05). The excellent and good rate of limb function in group A was significantly higher than that in group B (83.9% vs 66.7%, χ²=3.982, P=0.046).

Conclusion

Neoadjuvant chemotherapy combined with limb salvage surgery for patients with Enneking stage IIA or IIB limb osteosarcoma patients has better efficacy and can significantly improve limb function of patients.

Results of the Brazilian Osteosarcoma Treatment Group Studies III and IV: prognostic factors and impact on survival

PURPOSE

To evaluate the impact of chemotherapy and surgery on the outcome of osteosarcoma (OS) of the extremities and to identify prognostic factors in Brazilian patients.

PATIENTS AND METHODS

A total of 225 patients with metastatic and nonmetastatic OS of the extremities were enrolled and assessed in two consecutive studies designed and implemented by the Brazilian Osteosarcoma Treatment Group.

RESULTS

The 5-year survival and event-free survival rates for the 209 assessable patients were 50.1% and 39%, respectively; for the 178 patients with nonmetastatic disease at diagnosis, the rates were 60.5% and 45.5%, respectively. The multivariate analysis showed that the following variables were associated with a shorter survival: metastases at diagnosis (P < .001), necrosis grades 1 and 2 (P = .046), and tumor size (P = .0071).

CONCLUSION

The overall 5- and 10-year survival rates were lower than the rates reported in North American and European trials. A pattern of advanced disease at diagnosis was often present, with a high proportion of patients having metastases (20.8%) and large tumor size (42.9%). However, these features were not necessarily associated with longer duration of prediagnostic symptoms. These findings were considered in the strategic planning of the current Brazilian cooperative study, with the aim of improving survival and quality of life of a large number of patients with OS.

Research: Is resection of tumours involving the pelvic ring justified? : A review of 49 consecutive cases

Introduction

Pelvic surgery is challenging and impacts significantly on limb and visceral function, thus, raising the question "is heroic surgery justifiable". This study assessed the functional, oncologic and surgical outcomes following pelvis tumour resections.

Methods

Between 1996–2003, 49 patients (mean age 43 years) underwent pelvic tumour resections- 38 primary malignant tumours, 5 secondary tumours and 6 benign tumours. Bone tumours comprised 5 osteosarcomas, 5 Ewings sarcomas, and 12 chondrosarcomas. Of the soft tumours, 9 were of neural origin. Tumours involved the ilium, acetabulum, pubic bones, sacrum or a combination of these. Functional assessment was performed and no patient had metastases at presentation.

Results

There were 41 limb sparing resections and 8 hindquarter amputations. Surgical margins were intralesional (1), marginal (13), wide (26), and radical (3). Of limb sparing surgery, prosthetic reconstructions were performed in 10 patients, biologic reconstructions in 6, a combination of these in 3 and no reconstruction in others. There was 1 intraoperative death, 7 local recurrences and 19 metastases. Death from disease occurred at a mean of 14.2 months with a mean followup of 27 (1–96) months. Amputation and periacetabular resections had worse functional outcomes. Emotional acceptance was surprisingly high.

Conclusion

Pelvic resections are complex. Functional outcome is significantly affected by surgery. Disease control is similar to limb tumours. Emotional acceptance of surgery in survivors was surprisingly high. Major pelvic resection for malignancy appears justified.