56 research outputs found
Molecular Alterations Associated with Osteosarcoma Development
Osteosarcoma is the most frequent malignant primary bone tumor characterized by a high potency to form lung metastases which is the main cause of death. Unfortunately, the conventional chemotherapy is not fully effective on osteosarcoma metastases. The progression of a primary tumor to metastasis requires multiple processes, which are neovascularization, proliferation, invasion, survival in the bloodstream, apoptosis resistance, arrest at a distant organ, and outgrowth in secondary sites. Consequently, recent studies have revealed new insights into the molecular mechanisms of metastasis development. The understanding of the mechanism of molecular alterations can provide the identification of novel therapeutic targets and/or prognostic markers for osteosarcoma treatment to improve the clinical outcome
A combination of methotrexate and zoledronic acid prevents bone erosions and systemic bone mass loss in collagen induced arthritis
Introduction Osteoclasts play a key role in the pathogenesis of
bone erosion and systemic bone mass loss during rheumatoid
arthritis (RA). In this study, we aimed to determine the effect of
methotrexate (MTX) and zoledronic acid (ZA), used alone or in
combination, on osteoclast-mediated bone erosions and
systemic bone mass loss in a rat model of collagen induced
arthritis (CIA). We hypothesized that MTX and ZA could have an
additive effect to prevent both bone erosion and systemic bone
loss.
Methods Arthritis was induced in 64 female Sprague-Dawley
rats. After the clinical onset of CIA, rats were assigned to
treatment with MTX (1 mg/kg/week), ZA (100 ÎŒg/kg twice
weekly), both treatments at the same regimens, or vehicle.
Arthritis score and paw thickness were recorded twice weekly.
The rats were sacrificed on D28 and hind paws were removed
for radiographic, histological and immunohistochemical
analysis. The effects of treatments on osteoclastogenesis were
determined by Tartrate resistant acid phosphatase (TRAP)
staining. Micro-CT of the tibia was carried out for
histomorphometric analysis. Bone mass density was evaluated
by densitometry.
Results MTX significantly decreased the severity of CIA,
whereas ZA slightly exacerbated it. When these two drugs were
used in combination, MTX prevented the pro-inflammatory effect
of ZA. The combination of ZA with MTX was more effective than
MTX alone for reducing structural joint damage with a dramatic
decrease of osteoclasts' number in the eroded joints. However,
MTX alone also significantly reduced the number of osteoclasts
and the number of CD68+ mononuclear cells. ZA alone, or ZA
with MTX, significantly increased the systemic bone mass
density measured by densitometry and bone volume on
histomorphometric analysis.
Conclusions A combination of MTX and ZA prevented both
bone erosion and systemic bone loss in a rat model of arthritis.
Both treatments independently decreased the number of
osteoclasts in the eroded joint. However, while MTX probably
acts mainly through a decrease of inflammation, ZA has a direct
effect on osteoclasts, allowing a dramatic down-regulation of
these cells in inflamed joints. These two different mechanisms of
action provide support for the use of a combination of these two
drugs to improve the prevention of structural joint damage in RA
Ewing sarcoma from molecular biology to the clinic
In Europe, with an incidence of 7.5 cases per million, Ewing sarcoma (ES) is the second most common primary malignant bone tumor in children, adolescents and young adults, after osteosarcoma. Since the 1980s, conventional treatment has been based on the use of neoadjuvant and adjuvant chemotherapeutic agents combined with surgical resection of the tumor when possible. These treatments have increased the patient survival rate to 70% for localized forms, which drops drastically to less than 30% when patients are resistant to chemotherapy or when pulmonary metastases are present at diagnosis. However, the lack of improvement in these survival rates over the last decades points to the urgent need for new therapies. Genetically, ES is characterized by a chromosomal translocation between a member of the FET family and a member of the ETS family. In 85% of cases, the chromosomal translocation found is (11; 22) (q24; q12), between the EWS RNA-binding protein and the FLI1 transcription factor, leading to the EWS-FLI1 fusion protein. This chimeric protein acts as an oncogenic factor playing a crucial role in the development of ES. This review provides a non-exhaustive overview of ES from a clinical and biological point of view, describing its main clinical, cellular and molecular aspects
Current Therapeutic Strategies and Novel Approaches in Osteosarcoma
Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of cancer-related death in children and adolescents. Although long-term survival in localized osteosarcoma has improved to about 60% during the 1960s and 1970s, long-term survival in both localized and metastatic osteosarcoma has stagnated in the past several decades. Thus, current conventional therapy consists of multi-agent chemotherapy, surgery and radiation, which is not fully adequate for osteosarcoma treatment. Innovative drugs and approaches are needed to further improve outcome in osteosarcoma patients. This review describes the current management of osteosarcoma as well as potential new therapies
Characterization of Macrophages and Osteoclasts in the Osteosarcoma Tumor Microenvironment at Diagnosis: New Perspective for Osteosarcoma Treatment?
Biological and histopathological techniques identified osteoclasts and macrophages as targets of zoledronic acid (ZA), a therapeutic agent that was detrimental for patients in the French OS2006 trial. Conventional and multiplex immunohistochemistry of microenvironmental and OS cells were performed on biopsies of 124 OS2006 patients and 17 surgical (âOSNewâ) biopsies respectively. CSF-1R (common osteoclast/macrophage progenitor) and TRAP (osteoclast activity) levels in serum of 108 patients were correlated to response to chemotherapy and to prognosis. TRAP levels at surgery and at the end of the protocol were significantly lower in ZA+ than ZAâ patients (padj = 0.0011; 0.0132). For ZA+-patients, an increase in the CSF-1R level between diagnosis and surgery and a high TRAP level in the serum at biopsy were associated with a better response to chemotherapy (p = 0.0091; p = 0.0251). At diagnosis, high CD163+ was associated with good prognosis, while low TRAP activity was associated with better overall survival in ZAâ patients only. Multiplex immunohistochemistry demonstrated remarkable bipotent CD68+/CD163+ macrophages, homogeneously distributed throughout OS regions, aside osteoclasts (CD68+/CD163â) mostly residing in osteolytic territories and osteoid-matrix-associated CD68â/CD163+ macrophages. We demonstrate that ZA not only acts on harmful osteoclasts but also on protective macrophages, and hypothesize that the bipotent CD68+/CD163+ macrophages might present novel therapeutic targets
Safety Concern between Autologous Fat Graft, Mesenchymal Stem Cell and Osteosarcoma Recurrence
Background: Osteosarcoma is the most common malignant primary bone tumour in young adult treated by neo adjuvant
chemotherapy, surgical tumor removal and adjuvant multidrug chemotherapy. For correction of soft tissue defect
consecutive to surgery and/or tumor treatment, autologous fat graft has been proposed in plastic and reconstructive
surgery.
Principal Findings: We report here a case of a late local recurrence of osteosarcoma which occurred 13 years after the initial
pathology and 18 months after a lipofilling procedure. Because such recurrence was highly unexpected, we investigated the
possible relationship of tumor growth with fat injections and with mesenchymal stem/stromal cell like cells which are
largely found in fatty tissue. Results obtained in osteosarcoma pre-clinical models show that fat grafts or progenitor cells
promoted tumor growth.
Significance: These observations and results raise the question of whether autologous fat grafting is a safe reconstructive
procedure in a known post neoplasic context
Transforming Growth Factor-ÎČ Signaling Plays a Pivotal Role in the Interplay Between Osteosarcoma Cells and Their Microenvironment
Osteosarcomas are the most frequent form of primary bone tumors and mainly affect children, adolescents, and young adults. Despite encouraging progress in therapeutic management, including the advent of multidrug chemotherapy, the survival rates have remained unchanged for more than four decades: 75% at 5âyears for localized disease, but two groups of patients are still at high risk: metastatic at diagnosis (overall survival around 40% at 5âyears) and/or poor responders to chemotherapy (20% at 5âyears). Because these tumors are classified as âcomplex genomic,â it is extremely difficult to determine the signaling pathways that might be targeted by specific therapies. A hypothesis has thus emerged, stating that the particular microenvironment of these tumors may interfere with the tumor cells that promote chemoresistance and the dissemination of metastases. The stroma is composed of a large number of cell types (immune cells, endothelial cells, mesenchymal stromal cells, etc.) which secrete growth factors, such as transforming growth factor-ÎČ (TGF-ÎČ), which favors the development of primary tumors and dissemination of metastases by constituting a permissive niche at primary and distant sites. Rather than targeting the tumor cells themselves, which are very heterogeneous in osteosarcoma, the hypothesis is instead to target the key actors secreted in the microenvironment, such as TGF-ÎČs, which play a part in tumor progression. In the last decade, numerous studies have shown that overexpression of TGF-ÎČ is a hallmark of many cancers, including primary bone tumors. In this context, TGF-ÎČ signaling has emerged as a crucial factor in the cross talk between tumor cells and stroma cells in poor-prognosis cancers. Secretion of TGF-ÎČ by tumor cells or stroma cells can effectively act in a paracrine manner to regulate the phenotype and functions of the microenvironment to stimulate protumorigenic microenvironmental changes. TGF-ÎČ can thus exert its protumorigenic function in primary bone tumors by promoting angiogenesis, bone remodeling and cell migration, and by inhibiting immunosurveillance. This review focuses on the involvement of TGF-ÎČ signaling in primary bone tumor development, and the related therapeutic options that may be possible for these tumors
Human rheumatoid synovial cells (HRSC) in culture express TGF-ÎČ receptors and are growth stimulated by the factor
International audienceTGF-ÎČ (5 ng/ml) increased the proliferation rate of HRSC by 30 % after 96 h of treatment. One type of TGF-ÎČ binding system, with apparent Kd of 953 pM and a number of 29400 receptors/cell, was detected by Scatchard analysis of [125I]-TGF-ÎČ binding. Howewer, crosslinking experiments and SDS-PAGE separation showed five TGF-ÎČ binding proteins: 50, 70, 110, 140 and 400 kDa. We may suggest that the affinities of these receptors are too close to be revealed by-Scatchard plot. All together, the data suggest that TGF-ÎČ plays a role in the hyperplasia of RA synovial tissue
The Osteosarcoma Microenvironment: A Complex but Targetable Ecosystem
International audienceOsteosarcomas are the most frequent primary bone sarcomas, affecting mainly children, adolescents, and young adults, and with a second peak of incidence in elderly individuals. The current therapeutic management, a combined regimen of poly-chemotherapy and surgery, still remains largely insufficient, as patient survival has not improved in recent decades. Osteosarcomas are very heterogeneous tumors, both at the intra-and inter-tumor level, with no identified driver mutation. Consequently, efforts to improve treatments using targeted therapies have faced this lack of specific osteosarcoma targets. Nevertheless, these tumors are inextricably linked to their local microenvironment, composed of bone, stromal, vascular and immune cells and the osteosarcoma microenvironment is now considered to be essential and supportive for growth and dissemination. This review describes the different actors of the osteosarcoma microenvironment and gives an overview of the past, current, and future strategies of therapy targeting this complex ecosystem, with a focus on the role of extracellular vesicles and on the emergence of multi-kinase inhibitors
Differential expression of membrane-anchored proteoglycans in rabbit articular chondrocytes cultured in monolayers and in alginate beads. Effect of transforming growth factor-ÎČ1
International audienc
- âŠ