Osteosarcoma

Osteosarcoma growth suppression by riluzole delivery via iron oxide nanocage in nude mice

Osteosarcomas are the most commonly occurring malignant bone cancer in young individuals. The survival rate of patients with metastatic osteosarcoma is low and has been stagnant for over two decades. We previously demonstrated that the glutamate release inhibitor, riluzole inhibits osteosarcoma cell growth. Towards the development of more effective therapy, we investigated the delivery of riluzole in human metastatic osteosarcoma xenografts in mice. We compared the efficacy of riluzole delivery by intraperitoneally injecting either free riluzole or riluzole released via two different shapes of iron oxide nanoparticles (nanocage or nanosphere) of size 15±2.5 nm. We monitored tumor size using Vernier calipers and bioluminescence assay and found a significant reduction in tumor size in the riluzole-treated groups when injected, either in free form or via nanoparticles, compared to the control groups (PBS, nanosphere or nanocage). Importantly, nanocage-delivered riluzole was most effective in reducing tumor size in the xenograft nude mice. While riluzole delivery induced apoptosis in tumor tissues in all three groups of riluzole-treated animals, it was highest in tumors from the nanocage-delivered riluzole group. Therefore, we conclude that riluzole is an effective drug to reduce tumor size in osteosarcoma and the efficacy of riluzole as a apoptotic and tumor-reducing drug is enhanced when delivered via nanocage.

Establishment and characterization of a novel human osteosarcoma cell line for spontaneous pulmonary metastasis research in vivo

Background

A large number of osteosarcoma patients are dying of pulmonary metastasis in spite of the recent progress achieved in treatment research. Therefore, there is an urgent need for an in vivo experiment, whose purpose is to investigate the growth and metastasis of human osteosarcoma tumor. In this study, a novel human osteosarcoma cell line was established and characterized for osteosarcoma metastatic research in vivo.

Methods

Small pieces of parental primary osteosarcoma samples from a 16-year-old boy were xeno-transplanted into NOD/SCID mice. Then, osteosarcoma cells from the xeno-grafts were isolated and further passaged in vitro. Expression profiling was confirmed using HE staining and immunohistochemistry. The tumorigenic and metastatic ability of the established cell line was analyzed by cell scratch and CCK8 assay in vitro, and tumor transplantation in NOD/SCID mice.

Results

Parental cells were pleomorphic and positive with ALP, SSEA-4, and CD44. Osteosarcoma cells, named Well5 cells, were successfully isolated and had the ability of adipogenesis and osteogenesis. Well5 cells were mostly positive for SSEA-4 protein, and possessed morphological characteristics such as osteoblastic nature during the cultivation and hetero transplantation. Cell scratch and CCK8 assay indicated Well5 cells obtained a better capacity for migration and proliferation than the MG63 cell line. In NOD/SCID mice, orthotopic tumors were established at the primary site, and spontaneous pulmonary metastases were developed.

Conclusions

A novel human osteosarcoma cell line was successfully established, which may be helpful for spontaneous pulmonary metastasis research in vivo.

Primary Osteosarcoma in the Elderly Revisited: Current Concepts in Diagnosis and Treatment

PURPOSE OF REVIEW

Osteosarcoma is mostly seen in bones of children and young adults. When it occurs in older persons, the tumor is considered secondary usually complicating Paget disease or irradiated bone. However, there is a second incidence peak of primary osteosarcoma later in life when these tumors occur de novo. This article describes the clinical, imaging, and treatment of POS in older patients, including demographic data of patients from our institution.

FINDINGS

We present our experience with 920 cases of osteosarcoma that were seen between 1984 and 2003 at the University of Texas MD Anderson Cancer Center in Houston, TX, USA. Among the 868 primary osteosarcoma of bones, there were 100 (11.52%), which comprised 69% of the tumors in patients over the age of 50 years. Older patients with primary osteosarcoma tend to have relatively more common axial skeleton involvement, have more distant disease, and are difficult to treat because of concomitant comorbidities. Despite that, most adult patients treated with chemotherapy have shown good results with longer disease-free survival. A lytic bone lesion seen in radiographs of elderly patients should include primary osteosarcoma among differential diagnoses. Radical surgery and chemotherapy seem to ensure long-term disease-free survival in most cases. The elderly patients with POS in pelvis, spine, and upper extremities and those with distant disease (metastases) have worse prognosis.

Osteosarcoma cell proliferation and survival requires mGluR5 receptor activity and is blocked by Riluzole

Osteosarcomas are malignant tumors of bone, most commonly seen in children and adolescents. Despite advances in modern medicine, the poor survival rate of metastatic osteosarcoma has not improved in two decades. In the present study we have investigated the effect of Riluzole on a human and mouse metastatic osteosarcoma cells. We show that LM7 cells secrete glutamate in the media and that mGluR5 receptors are required for the proliferation of LM7 cells. Riluzole, which is known to inhibit glutamate release, inhibits proliferation, induces apoptosis and prevents migration of LM7 cells. This is also seen with Fenobam, a specific blocker of mGluR5. We also show that Riluzole alters the phosphorylation status of AKT/P70 S6 kinase, ERK1/2 and JNK1/2. Thus Riluzole is an effective drug to inhibit proliferation and survival of osteosarcoma cells and has therapeutic potential for the treatment of osteosarcoma exhibiting autocrine glutamate signaling.

An improved intrafemoral injection with minimized leakage as an orthotopic mouse model of osteosarcoma

Osteosarcoma, the most common type of primary bone cancer, is the second highest cause of cancer-related death in pediatric patients. To understand the mechanisms behind osteosarcoma progression and to discover novel therapeutic strategies for this disease, a reliable and appropriate mouse model is essential. For this purpose, osteosarcoma cells need to be injected into the bone marrow. Previously, the intratibial and intrafemoral injection methods were reported; however, the major drawback of these methods is the potential leakage of tumor cells from the injection site during or after these procedures. To overcome this, we have established an improved method to minimize leakage in an orthotopic mouse model of osteosarcoma. By taking advantage of the anatomical benefits of the femur with less bowing and larger medullary cavity than those of the tibia, osteosarcoma cells are injected directly into the femoral cavity following reaming of its intramedullary space. To prevent potential leakage of tumor cells during and after the surgery, the injection site is sealed with bone wax. This method requires a minor surgery of approximately 15min under anesthesia. Our established orthotopic osteosarcoma model could serve as a valuable and reliable tool for examining progression of various types of bone tumors.

Inhibition of human osteosarcoma cell migration and invasion by a gene silencer, pyrrole-imidazole polyamide, targeted at the human MMP9 NF-κB binding site

Osteosarcoma is one of the most prevalent bone tumors, occurring mostly in adolescence. However, no noticeable progress has been achieved in developing new therapeutic agents for this disease. Matrix metalloproteinase 9 (MMP9), a type IV collagenase, is a known anticancer target and is overexpressed in osteosarcomas. MMPs can degrade components of the extracellular matrix and are known to be involved in tumor invasion and metastasis. In the present study, we designed and synthesized a pyrrole-imidazole polyamide (HN.49), a gene-silencing agent that specifically targets the nuclear factor-kappa B (NF-κB) binding site of the human MMP9 promoter. We then examined the effect of HN.49 on the enzyme activity of MMP9 and the migration activity of osteosarcoma cells in vitro. It was clearly shown that HN.49 polyamide reduced the expression level of MMP9 mRNA and the enzymatic activity of MMP-9 in SaOS-2 cells. Moreover, HN.49 polyamide inhibited migration and invasion by SaOS-2 cells in in vitro wound-closure and matrigel-invasion assays. These results indicate that HN.49 may be a potential therapeutic agent for inhibiting the invasion and metastasis of osteosarcoma.

Focal adhesion kinase is involved in the migration of human osteosarcoma cells

The aim of the present study was to analyze the expression of focal adhesion kinase (FAK) in osteosarcoma (OS) cell lines with different migration abilities in order to determine the role of FAK in migration. A number of different 143B subclone cell lines (A1, A2, A3, A4 and A5) were obtained by a limiting dilution method, and the expression of FAK was detected using western blot analysis. The role of FAK in the migration of OS cells was investigated using small interfering RNA (siRNA), and the ratio of the number of lamellipodia was compared by immunofluorescence staining. The A2 and A3 OS 143B subclone cell lines demonstrated a stronger migration ability and exhibited higher FAK expression compared with the A1 cell line (P<0.05). Following transfection with FAK-siRNA, the migration ability of the A3 cells was significantly decreased (P<0.05), and the ratio of the number of lamellipodia formed was reduced from 35 to 11% (P<0.05). In conclusion, the level of FAK expression was higher in the cell lines with a stronger migration ability. FAK affects the migration ability of OS cells by suppressing the formation of lamellipodia.

Sarcomas

Malignant bone tumors (osteosarcoma, Ewing sarcoma) and soft-tissue sarcomas (rhabdomyosarcoma, nonrhabdomyosarcoma) account for approximately 14% of childhood malignancies. Successful treatment of patients with sarcoma depends on a multidisciplinary approach to therapy, including oncology, surgery, radiation oncology, radiology, pathology, and physiatry. By combining systemic treatment with chemotherapy and primary tumor control using surgery and/or radiation, survival rates for localized disease range from 70% to 75%. However, children with metastatic or recurrent disease continue to have dismal outcomes. A better understanding of the biology underlying both bone and soft-tissue sarcomas is required to further improve outcomes for children with these tumors.

Synthesis, characterization and anti-proliferative activity of Cd(II) complexes with NNN type pyrazole-based ligand and pseudohalide ligands as coligand

Cd(II) complexes of tridentate nitrogen donor ligand, 2,6-bis(3,4,5-trimethylpyrazolyl)pyridine (btmpp), Cd(btmpp)X2 (X:Cl, ONO or N(CN)2) have been synthesized and characterized by elemental and spectral (FT-IR, (1)H NMR, (13)C NMR, UV-Vis) analyses, differential thermal analysis and single crystal X-ray diffraction studies. The molecular structure of reported complex 1, revealed distorted square-pyramidal geometry around Cadmium. Complexes 1-3 and corresponding ligand were tested for cytotoxic activity against the human carcinoma cell lines HEP3B (hepatocellular carcinoma), PC3 (prostate adenocarcinoma), MCF7 (breast adenocarcinoma) and Saos2 (osteosarcoma). The results show that, complexes are more cytotoxic than the free ligand and complex 2 is the most cytotoxic complex for PC3.

Dihydroartemisinin inhibits tumor growth of human osteosarcoma cells by suppressing Wnt/β-catenin signaling

Osteosarcoma (OS) is the most common type of bone cancer. Even with early diagnosis and aggressive treatment, the prognosis for OS is poor. In the present study, we investigated the proliferation and invasion inhibitory effect of dihydroartemisinin (DHA) on human OS cells and the possible molecular mechanisms involved. We demonstrated that DHA can inhibit proliferation, decrease migration, reduce invasion and induce apoptosis in human OS cells. Using an in vivo tumor animal model, we confirmed that DHA can prevent OS formation and maintain intact bone structure in athymic mice. In addition, we examined the possible molecular mechanisms mediating the function of DHA. We found that the total protein levels and transcriptional activity of β-catenin in OS cells are reduced by DHA treatment, and this may result from the increased catalytic activity of glycogen synthase kinase 3β (GSK3β). Moreover, the inhibitory effect of DHA on OS cells is reversed by overexpression of β-catenin, but is further enhanced by knockdown of β-catenin, respectively. Collectively, our results reveal that DHA can inhibit tumor growth of OS cells by inactivating Wnt/β-catenin signaling. Therefore, DHA is a promising chemotherapy agent in the treatment of human OS.

IGFBP5 domains exert distinct inhibitory effects on the tumorigenicity and metastasis of human osteosarcoma

Osteosarcoma (OS) is the most common primary malignancy of bone. We investigated the roles of insulin-like growth factor binding protein 5 (IGFBP5) domains in modulating OS tumorigenicity and metastasis. The N-terminal (to a lesser extent the C-terminal) domain inhibited cell proliferation and induced apoptosis while the C-terminal domain inhibited cell migration and invasion. The Linker domain had no independent effects. In vivo, the N-terminal domain decreased tumor growth without affecting pulmonary metastases while the C-terminal domain inhibited tumor growth and metastases. In summary, the N- and C-terminal domains modulated OS tumorigenic phenotypes while the C-terminal domain inhibited OS metastatic phenotypes.

Expression and localization of TASK-1, -2 and -3 channels in MG63 human osteoblast-like cells

It is well known that a number of ion channels are involved in the proliferation, migration and invasion of tumor cells. TASK channels, an acid-sensitive subgroup of the two-pore-domain K⁺ channel (K2P) family, are expressed in numerous types of tissue and exhibit various physiological functions depending on the cell type. In the present study, we employed RT-PCR and western blot analysis to determine the expression of TASK-1, -2 and -3 at the mRNA and protein levels in MG63 human osteoblast-like cells. Immunofluorescence with specific antibodies against the TASK channels revealed the localization patterns at the plasma membrane and the juxtanuclear compartment. The induced fluctuations in the extracellular pH from 7.4 to 6.9 and to 6.4 significantly reduced the proliferation rate of MG63 cells by 44.3 and 90.1%, respectively. These data revealed the expression of TASK-1, -2 and -3, and the correlation between TASK channels and cell proliferation in MG63 cells, suggesting that these channels may be involved in the tumorigenesis of osteosarcoma.

Comparison of the outcome of conventional osteosarcoma at two specialist international orthopaedic oncology centres

OBJECTIVE

To determine the prognostic value of patient and treatment parameters in osteosarcoma, and whether these are equally important across international boundaries.

DESIGN

Retrospective, cross-sectional study of 428 patients diagnosed with around-knee osteosarcoma, between 1990 and 1997 in Birmingham, UK, and Bologna, Italy. Disease-free survival (DFS) and overall survival (OS) assessed by Kaplan-Meier, Fisher's PLSD and Cox proportional hazard regression.

RESULTS

Five-year DFS and OS were 56 and 73% at Centre 1, compared to 43 and 60% at Centre 2 (P=0.0022 and P = 0.025, respectively). The most important bad prognostic factors for DFS and OS respectively were raised alkaline phosphatase at diagnosis (P=0.002 and P=0.003), tumour necrosis < 90% following chemotherapy (P=0.001 and P = 0.004) and volume > 150 cm(3) at diagnosis (P=0.04 and P=0.006). The most significant combination of bad prognostic factors was alkaline phosphatase and tumour necrosis. A total of 73% of patients at Centre 1 had greater than 90% necrosis of the tumour following neoadjuvant chemotherapy compared with 29% at Centre 2.

CONCLUSIONS

Tumour-based prognostic factors have similar significance across international boundaries. Chemotherapy effectiveness appears to be a major factor in explaining the survival difference between the two centres.

Phosphorylated c-Jun and Fra-1 induce matrix metalloproteinase-1 and thereby regulate invasion activity of 143B osteosarcoma cells

Osteosarcoma is the most common primary malignancy of bone and patients often develop pulmonary metastases. Despite the advances in surgical and medical management, the mechanisms underlying human osteosarcoma progression and metastasis remain to be elucidated. Gene expression profiles were compared by the cDNA microarray technique between two different human osteosarcoma sublines, MNNG/HOS and 143B, which differ greatly in spontaneous pulmonary metastatic potential. Here we report an enhanced expression of matrix metalloproteinase (MMP)-1 in the highly metastatic human osteosarcoma cell line 143B. Moreover, the in vitro invasion activity of 143B cells was MMP-1-dependent. The activator protein (AP)-1 binding site in the MMP-1 gene promoter was required for the constitutive expression of MMP-1 in 143B cells. Two AP-1 components, c-Jun and Fra-1, were phosphorylated, and bound to the AP-1 binding site of the MMP-1 promoter in 143B cells. Activated c-Jun and Fra-1 were essential for MMP-1 gene expression in 143B cells. Mitogen-activated protein kinase pathways including the c-Jun NH(2)-terminal kinase and the extracellular signal-regulated kinase activate c-Jun and Fra-1 and thereby regulate c-Jun/Fra-1 mediated events, establishing the mitogen-activated protein kinase/AP-1/MMP-1 axis as important in 143B cells. These data suggest that MMP-1 plays a central role in osteosarcoma invasion. Accordingly, MMP-1 might be a biomarker and therapeutic target for invasive osteosarcomas and pulmonary metastases.

Insulin-like growth factor binding protein 5 suppresses tumor growth and metastasis of human osteosarcoma

Osteosarcoma (OS) is the most common primary malignancy of bone. There is a critical need to identify the events that lead to the poorly understood mechanism of OS development and metastasis. The goal of this investigation is to identify and characterize a novel marker of OS progression. We have established and characterized a highly metastatic OS subline that is derived from the less metastatic human MG63 line through serial passages in nude mice via intratibial injections. Microarray analysis of the parental MG63, the highly metastatic MG63.2 subline, as well as the corresponding primary tumors and pulmonary metastases revealed insulin-like growth factor binding protein 5 (IGFBP5) to be one of the significantly downregulated genes in the metastatic subline. Confirmatory quantitative RT-PCR on 20 genes of interest demonstrated IGFBP5 to be the most differentially expressed and was therefore chosen to be one of the genes for further investigation. Adenoviral mediated overexpression and knockdown of IGFBP5 in the MG63 and MG63.2 cell lines, as well as other OS lines (143B and MNNG/HOS) that are independent of our MG63 lines, were employed to examine the role of IGFBP5. We found that overexpression of IGFBP5 inhibited in vitro cell proliferation, migration and invasion of OS cells. Additionally, IGFBP5 overexpression promoted apoptosis and cell cycle arrest in the G1 phase. In an orthotopic xenograft animal model, overexpression of IGFBP5 inhibited OS tumor growth and pulmonary metastases. Conversely, siRNA-mediated knockdown of IGFBP5 promoted OS tumor growth and pulmonary metastases in vivo. Immunohistochemical staining of patient-matched primary and metastatic OS samples demonstrated decreased IGFBP5 expression in the metastases. These results suggest 1) a role for IGFBP5 as a novel marker that has an important role in the pathogenesis of OS, and 2) that the loss of IGFBP5 function may contribute to more metastatic phenotypes in OS.

Lysophosphatidic acid acyltransferase β (LPAATβ) promotes the tumor growth of human osteosarcoma

Background

Osteosarcoma is the most common primary malignancy of bone with poorly characterized molecular pathways important in its pathogenesis. Increasing evidence indicates that elevated lipid biosynthesis is a characteristic feature of cancer. We sought to investigate the role of lysophosphatidic acid acyltransferase β (LPAATβ, aka, AGPAT2) in regulating the proliferation and growth of human osteosarcoma cells. LPAATβ can generate phosphatidic acid, which plays a key role in lipid biosynthesis as well as in cell proliferation and survival. Although elevated expression of LPAATβ has been reported in several types of human tumors, the role of LPAATβ in osteosarcoma progression has yet to be elucidated.

Methodology/Principal Findings

Endogenous expression of LPAATβ in osteosarcoma cell lines is analyzed by using semi-quantitative PCR and immunohistochemical staining. Adenovirus-mediated overexpression of LPAATβ and silencing LPAATβ expression is employed to determine the effect of LPAATβ on osteosarcoma cell proliferation and migration in vitro and osteosarcoma tumor growth in vivo. We have found that expression of LPAATβ is readily detected in 8 of the 10 analyzed human osteosarcoma lines. Exogenous expression of LPAATβ promotes osteosarcoma cell proliferation and migration, while silencing LPAATβ expression inhibits these cellular characteristics. We further demonstrate that exogenous expression of LPAATβ effectively promotes tumor growth, while knockdown of LPAATβ expression inhibits tumor growth in an orthotopic xenograft model of human osteosarcoma.

Conclusions/Significance

Our results strongly suggest that LPAATβ expression may be associated with the aggressive phenotypes of human osteosarcoma and that LPAATβ may play an important role in regulating osteosarcoma cell proliferation and tumor growth. Thus, targeting LPAATβ may be exploited as a novel therapeutic strategy for the clinical management of osteosarcoma. This is especially attractive given the availability of selective pharmacological inhibitors.

Establishment and characterization of a new highly metastatic human osteosarcoma cell line

Osteosarcoma is the most common primary malignancy of bone in children and young adults. There is a paucity of tumorigenic and highly metastatic human osteosarcoma cell lines that have not been further transformed by exogenous means. Here we establish and characterize a highly metastatic human osteosarcoma cell line that is derived from a poorly metastatic MG63 line through serial passage in nude mice via intratibial injections. The occasional pulmonary metastases developed from MG63 were harvested and repassaged in mice until a highly metastatic subline (MG63.2) was established. The parental MG63 and highly metastatic MG63.2 cells were further characterized in vitro and in vivo. MG63.2 cells demonstrated increased cell migration and invasion compared to the parental MG63 cells. Conversely, cell adhesion was significantly greater in MG63 cells when compared to the MG63.2 cells. MG63.2 cells grew at a slightly slower rate than that of the parental cells. When injected into nude mice, MG63.2 cells had a greater than 200-fold increase in developing pulmonary metastases compared to the parental MG63 cells. MG63.2 cells also formed larger primary tumors when compared to the parental MG63 cells. Further analysis revealed that ezrin expression was up-regulated in the metastatic MG63.2 cells. Interestingly, expressions of MMP-2 and MMP-9 were down-regulated, and expression of TIMP-2 was up-regulated in the MG63.2 cells. Taken together, we have established and characterized a highly metastatic human osteosarcoma cell line that should serve as a valuable tool for future investigations on the pathogenesis, metastasis, and potential treatments of human osteosarcoma.

Detection of somatostatin receptors in human osteosarcoma

Background

The location of osteosarcoma in the metaphysis as well as the age of the patients during the most rapid tumour growth suggest that factors related to skeletal growth are involved in the pathogenesis of this tumour. In this aspect this study aims to detect somatostatin receptors in human osteosarcomas and correlate this finding with the clinical outcome of the tumour.

Patients and methods

Immunohistochemical staining for the presence of somatostatin receptors as well as overall survival and disease free survival rates were retrospectively studied in twenty-nine osteosarcoma patients.

Results

Four osteosarcomas with several aggressive biologic behaviour expressed somatostatin receptors. In these four young patients the event free rate was 0% and the overall survival rate was 50% at 4, 3 years. In contrast the event free survival rate of the twenty-five patients with negative somatostatin receptor status was 72% with an overall survival rate of 76% at 4,3 years.

Conclusion

The present study demonstrates the existence of somatostatin receptors in human osteosarcoma. Tumours expressing somatostatin receptors seemed to be aggressive with a very low disease free and overall survival rate compared to osteosarcoma with negative receptor status.

S100A6 expression and function in human osteosarcoma

There is a critical need to identify markers that can accurately identify existing or predict future metastatic disease in patients with osteosarcoma since the majority of patients present with undetectable micrometastatic disease. We previously reported S100A6 is overexpressed in human osteosarcoma and increased expression of S100A6 by immunohistochemistry correlated with decreased clinical metastasis. We have established 11 primary cultures from biopsies of patients with osteosarcoma and ten of the 11 primary cultures have increased expression of S100A6 relative to normal human osteoblasts. To further explore possible mechanisms for metastasis suppression previously reported, we used in this report siRNA-mediated knockdown of S100A6 in four commonly used human osteosarcoma lines, then examined their cell adhesion, migration, and invasion properties. Knockdown of S100A6 expression inhibited cell adhesion and promoted cell migration and invasion in these lines. Conversely, S100A6 overexpression enhanced cell adhesion and inhibited cell invasion. Our data demonstrate S100A6 is commonly overexpressed in human osteosarcoma. S100A6 may inhibit osteosarcoma metastasis by promoting cell adhesion and inhibiting cell motility and invasion. Thus, S100A6 may be considered a potential marker for human osteosarcoma with prognostic value for identifying patients without metastases.

Osteosarcoma development and stem cell differentiation

Osteosarcoma is the most common nonhematologic malignancy of bone in children and adults. The peak incidence occurs in the second decade of life, with a smaller peak after age 50. Osteosarcoma typically arises around the growth plate of long bones. Most osteosarcoma tumors are of high grade and tend to develop pulmonary metastases. Despite clinical improvements, patients with metastatic or recurrent diseases have a poor prognosis. Here, we reviewed the current understanding of human osteosarcoma, with an emphasis on potential links between defective osteogenic differentiation and bone tumorigenesis. Existing data indicate osteosarcoma tumors display a broad range of genetic and molecular alterations, including the gains, losses, or arrangements of chromosomal regions, inactivation of tumor suppressor genes, and the deregulation of major signaling pathways. However, except for p53 and/or RB mutations, most alterations are not constantly detected in the majority of osteosarcoma tumors. With a rapid expansion of our knowledge about stem cell biology, emerging evidence suggests osteosarcoma should be regarded as a differentiation disease caused by genetic and epigenetic changes that interrupt osteoblast differentiation from mesenchymal stem cells. Understanding the molecular pathogenesis of human osteosarcoma could ultimately lead to the development of diagnostic and prognostic markers, as well as targeted therapeutics for osteosarcoma patients.

Gene therapy for osteosarcoma: steps towards clinical studies

Gene therapy, an applied form of biotechnology, relies on the delivery of foreign DNA into cells. More than 50% of all reported clinical trials for gene therapy are for cancer, though only a scant number for osteosarcoma. Osteosarcoma is a neoplasm afflicting young adults, who in their prime years of life suffer debilitation if not death. The disease is not entirely curable, even with surgery combined with aggressive chemotherapy. Thus, other forms of therapies are being evaluated, including gene therapy. There exist two major forms of gene transfer: viral and non-viral. This review only covers proof-of-principle work carried out in cancer beyond the cell culture stage, in animals. Drawing from the experiences of gene therapy against other cancers, studies for which have already reached the clinical phase, the review discusses potential pitfalls and solutions to enhance gene therapy for osteosarcoma.

Parthenolide, a natural inhibitor of Nuclear Factor-kappaB, inhibits lung colonization of murine osteosarcoma cells

PURPOSE

The transcription factor nuclear factor-kappaB (NF-kappaB) regulates the expression of several genes important for tumor metastasis and is constitutively active in the highly metastatic murine osteosarcoma cell line LM8. Parthenolide, a sesquiterpene lactone, was reported to inhibit the DNA binding of NF-kappaB. The purpose of this study is to investigate the usefulness of parthenolide as target for antimetastatic therapies.

EXPERIMENTAL DESIGN

We examined the effect of parthenolide on metastasis-associated phenotypes in vitro and in murine experimental lung metastasis models by s.c. and i.v. inoculation of LM8 cells.

RESULTS

We found that parthenolide strongly induced apoptosis and inhibited cell proliferation and the expression of vascular endothelial growth factor in vitro. In the in vivo metastasis models, parthenolide treatment suppressed lung metastasis when treatment was initiated concurrently with s.c. or i.v. inoculation of tumor cells, whereas lung metastasis was not reduced when parthenolide was given after the homing of tumor cells. The growth of s.c. tumors that developed at the inoculation site was not suppressed by parthenolide. We also found that the genetic inhibition of NF-kappaB activity by expressing mutant IkappaBalpha suppressed lung metastasis in vivo but not s.c. tumor growth. This supports our notion that the metastasis-preventing effect of parthenolide is mediated at least in part by inhibition of NF-kappaB activity.

CONCLUSIONS

These findings suggested that NF-kappaB is a potential molecular target for designing specific prophylactic interventions against distant metastasis and that parthenolide is a hopeful candidate for an antimetastatic drug.

Human xenograft osteosarcoma models with spontaneous metastasis in mice: clinical relevance and applicability for drug testing

Osteosarcoma cells derived from patients have been isolated and subsequently cultured for the past 35 years. To date though, there have been no major breakthroughs in the development of a model for osteosarcoma that uses orthotopic implantation of human osteosarcoma cells and that closely emulates the clinical progression of this debilitating and fatal disease. Such a model is long overdue given the devastating demographics (second highest cause of cancer-related death in the paediatric age group) of the ailment and the lack of solid options for control, if not cure, for the disease, as it also is the most common primary tumour of bone. Only then can more robust R & D be undertaken in the search for efficacious anti-osteosarcoma agents. This review tackles this conundrum and lists the variety of models (that use human osteosarcoma cells) available and the types of studies performed with these.

Osteosarcoma of rib in a seven-year-old child: a case report

Primary tumours of ribs are relatively uncommon in adults and are even rarer in children. (William in Am Surg June: 338-342, 1972; Eskenasy in Rev Roum Morph Embryol Physio 1:35-50, 1985) Osteosarcoma is the most common primary bone malignancy in children and young adults. (Whelan in Eur J Can 33(10):1611-1619, 1997) Very few cases of osteosacoma of the rib have been described in literature. We report a 7-year-old girl with primary osteosarcoma of the rib which was managed by wide excision followed by adjuvant chemotherapy. She is disease free after 12 months of follow-up. We believe our case to be the youngest with primary osteosarcoma of the rib. Primary osteosarcoma of the rib should be considered in the differential diagnosis in a child with rib swelling. Early diagnosis and treatment improves the outcome.

Increased expression of S100A6 is associated with decreased metastasis and inhibition of cell migration and anchorage independent growth in human osteosarcoma

While most osteosarcoma patients have metastatic or micrometastatic lesions, less than 15% of them have clinically detectable metastatic diseases at presentation. To identify potential markers that may predict osteosarcoma metastasis, we analyzed the expression of S100A6 in 50 osteosarcoma cases and found that 84% of the analyzed specimens stained positive for S100A6. There is a trend towards decreased clinically evident metastasis with increased S100A6 staining. Overexpression of S100A6 in osteosarcoma cells decreases cell motility and anchorage independent growth on collagen gels. Our findings provide evidence that, while S100A6 is commonly overexpressed in human osteosarcoma, loss of its expression correlates with a metastatic phenotype.

Evaluating physical function in an adolescent bone tumor population

BACKGROUND

Survival rates for patients with bone tumors have increased dramatically over the past few decades. Unfortunately, many patients face functional limitations resulting from disease management, but there is little evidence regarding physical functioning in adolescents with bone tumors. This lack is largely due to the absence of a standardized measure for evaluating adolescent sarcoma physical functioning. This review discusses considerations in searching for a measure of adolescent physical functioning, evaluates measures previously used in assessing functional outcome in young sarcoma patients, reviews self-report measures of pediatric physical functioning, and makes recommendations for future research.

PROCEDURE

Electronic databases were searched for studies published between 1980 and 2004. Studies examining physical functioning in adolescent sarcoma patients and those describing measures of pediatric physical functioning were included.

RESULTS

The study includes measures previously used in the adolescent bone tumor literature (Musculoskeletal Tumor Society, Mankin, Groningen Activity Restriction Scale, Toronto Extremity Salvage Score [TESS]), and three measures of pediatric physical function (Functional Disability Inventory, Pediatric Outcomes Data Collection Instrument [PODCI], Activities Scale for Kids [ASK]). The TESS, PODCI, and ASK each met at least four of the outlined applicability and feasibility components.

CONCLUSION

The search for a measure of physical functioning for adolescent sarcoma patients requires an exploration of many developmental and measurement issues. Based on the sensibility review presented, the TESS, PODCI, and ASK are recommended for further evaluation of content and of the measurement properties of reliability, validity, and responsiveness, prior to their use in evaluating adolescent sarcoma patients.

Limb salvage in the skeletally immature patient

The most common tumors of bone, osteosarcoma and Ewing sarcoma, commonly occur in the skeletally immature patient. Historically, amputation was the procedure of choice; however, improved oncologic outcome and technical advances in limb salvage surgery have made limb salvage therapy a feasible and valuable treatment option. Nevertheless, depending on the extent of the lesion within the long bone, it may be difficult to spare the physis, and hence, in the skeletally immature patient, resection of a sarcoma of bone can create a limb-length discrepancy and gait abnormalities. This article reviews the limb salvage options available for the skeletally immature patient who requires reconstruction of a segmental long bone defect.

An Orthotopic Model of Human Osteosarcoma Growth and Spontaneous Pulmonary Metastasis

Osteosarcoma is the most common primary malignancy of bone and patients often develop pulmonary metastases. In order to investigate the pathogenesis of human osteosarcoma, there is a great need to develop a clinically relevant animal model. Here we report the development of an osteosarcoma animal model using three related human osteosarcoma lines, the parental TE-85 and two derivative lines MNNG/HOS and 143B. In vitro characterization demonstrated that the 143B line had the greatest cell migration and the least cell adhesion activities among the three lines. The 143B line also exhibited the greatest ability for anchorage independent growth. When GFP-tagged osteosarcoma cells were injected into the proximal tibia of athymic mice, we found that 143B cells were highly tumorigenic and metastatic, and MNNG/HOS cells were tumorigenic but significantly less metastatic. TE85 cells were neither tumorigenic nor metastatic. The number of pulmonary metastases was found 50-fold higher in 143B injected animals than that in MNNG/HOS injected mice. No pulmonary metastases were detected in TE85 injected animals for up to 8 weeks. Primary tumors formed by MNNG/HOS and 143B cells could be visualized by whole body fluorescence imaging, while the pulmonary metastases were visualized on the necropsied samples. The GFP tagged 143B cells (and to a lesser extent, MNNG/HOS cells) were readily recovered from lung metastases. This clinically relevant model of human osteosarcoma provides varying degrees of tumor growth at the primary site and metastatic potential. Thus, this orthotopic model should be a valuable tool to investigate factors that promote or inhibit osteosarcoma growth and/or metastasis.

Multiple Primary Cancers in Patients With Osteosarcoma

One hundred thirty-five patients younger than 30 years with osteosarcoma were treated at the Chiba Cancer Center between 1976 and 1999. They included six patients with second cancer after cure of osteosarcoma (group A) and three patients with osteosarcoma as second cancer after cure of childhood cancers (group B). Third cancer occurred in one patient of group A. The clinical features of these nine patients were studied. The diagnoses of second cancer in group A consisted of two acute myelogenous leukemias, two breast carcinomas, one malignant phyllodes tumor of breast, and one ovarian carcinoma. The third cancer was uterine leiomyosarcoma. Second cancer occurred an average of 7.2 years after occurrence of osteosarcoma. The diagnoses of first cancer in group B consisted of one adrenocortical carcinoma, one malignant teratoma of sacrum, and one ovarian carcinoma (yolk sac tumor). Osteosarcoma occurred on average 12.7 years after occurrence of first cancer. Two patients had germ-line p53 gene mutation. Anticancer drugs and genetic factors are presumed to be concerned with occurrence of second cancer. The frequency of multiple primary cancers in patients with osteosarcoma is by no means low. Strict follow-up is thus needed over a long period.

HER-2/neu and p53 in osteosarcoma: an immunohistochemical and fluorescence in situ hybridization analysis

The overexpression of HER-2/neu and p53 has been associated with poor outcome in many neoplasms. Their role in patients with osteosarcoma is unclear. We studied the expression of HER-2/neu and p53 in 22 osteosarcoma samples (from 20 patients--2 had locally recurrent disease) biopsied at the University of Medicine and Dentistry of New Jersey (UMDNJ) from 1996-2000 using both immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) analysis. Fourteen patients (14 samples) presented with Stage II and 6 patients (8 samples) presented with Stage III disease. Median follow-up is two years (range one year to five years). Four of 22 (18%) samples showed focal membranous or cytoplasmic positivity for HER-2/neu and six of 22 samples (27%) showed nuclear positivity for p53 by IHC analysis. In contrast, none of 22 tested samples showed gene amplification for HER-2/neu by FISH analysis. Seven of 13 HER-2/neu and p53 negative patients (54%) are currently disease free (between one year to five years). In this sample of patients, the HER-2/neu oncogene is not overexpressed or amplified in osteosarcoma; six of 22 samples (27%) showed overexpression of p53 by IHC analysis. By FISH, none of the samples demonstrated deletion of p53. Neither HER2/neu nor p53 expression was important for the biology of osteosarcoma in this population.

Outcome of flat bone sarcomas (other than Ewing's) in children and adolescents: a study of 25 cases

We analysed the clinical features and outcome of young patients with non-Ewing's flat bone sarcoma treated during the era of contemporary chemotherapy. The characteristics and outcome of 25 patients (15 males and 10 females) with primary or radiation-related flat bone sarcoma treated in the Pediatrics Department at the Institut Gustave Roussy from 1981 to 1999 were reviewed. In all, 20 patients had osteosarcoma, four chondrosarcoma and one malignant fibrous histiocytoma. The age at diagnosis ranged from 2 to 23 years (median, 15 years). Nine tumours were located in the craniofacial bones, 11 in the pelvis and five in flat bones at other sites. Four patients had metastatic disease at diagnosis. Radiation-associated flat bone osteosarcoma was diagnosed in 10 out of 25 cases. The projected overall survival and event-free survival (EFS) rates at 5 years were 45.1 and 34.3% for all the 25 patients. The EFS rate of patients with second bone sarcoma was similar to that of patients with de novo flat bone sarcoma (P=0.1). The aim of treatment was curative for 24 patients, 23 of whom were treated with intensive chemotherapy regimens and 19 with surgery. Significant adverse prognostic factors on survival included incomplete surgical resection (P=0.001) and use of regimens without pre- and postoperative chemotherapy (P=0.007). Nine of the 25 patients were treated with pre- and postoperative chemotherapy and complete surgical resection. Among them, eight are alive with no disease. Radical surgical resection is the overriding prognostic factor for flat bone sarcomas in young patients. Nevertheless, our results suggest a more favourable outcome since the advent of intensive chemotherapy.

Marriage and fertility in long-term survivors of high grade osteosarcoma

One hundred fifteen patients with high grade osteosarcoma were treated at our hospital between 1976 and 1995. Of these, 45 patients still surviving and disease free for more than 5 years since the conclusion of treatment were enrolled as the subjects. The marriage proportion (number of married persons/number of all persons) and fertility proportion (number of persons having an offspring/number of married persons) of these 45 patients were investigated. The marriage proportion of male patients was 20.8% (5/24), whereas that of female patients was 76.2% (16/21). The marriage proportion in male patients was dramatically lower than that in female patients (p = 0.0003). The marriage proportion in male patients was significantly lower than that in brothers of the patients (p = 0.0223). In female patients, the treatment of osteosarcoma had no influence on marriage, whereas in male patients it had a great influence on marriage. The fertility proportion in married patients was 76.2% (16/21) and that in siblings of the patients was 81.0% (17/21). A total of 18 offspring were born to married patients. These offspring had no birth defects or congenital anomalies. The chemotherapy used in the treatment of osteosarcoma had little influence on the fertility of patients or the health of their offspring.

Overexpression of cadherins suppresses pulmonary metastasis of osteosarcoma in vivo

Osteosarcoma by nature shows aggressive pulmonary metastasis; however, the underlying molecular mechanisms remain unclear. We previously showed that N-cadherin and cadherin-11 (OB-cadherin), which are highly expressed in normal osteoblasts, are anomalously expressed in human osteosarcoma (Kashima et al., Am J Pathol 1999;155:1549-55). In the present study, we examined the role of cadherins in osteosarcoma metastasis using the mouse osteosarcoma cell line Dunn and its highly metastatic subline LM8. Oligonucleotide array and RT-PCR analyses demonstrated that Dunn and LM8 cells did not express appreciable levels of several members of the cadherin family, and Western blot analysis confirmed that Dunn and LM8 cells did not express P-cadherin, E-cadherin, N-cadherin or cadherin-11 protein. We therefore investigated the functional consequences of cadherin overexpression on cell migration and in vivo metastatic potential of LM8 cells. Several LM8 clones were isolated which expressed exogenous N-cadherin and cadherin-11 localized to the cell membrane and able to bind to beta-catenin. Overexpression of N-cadherin or cadherin-11 in LM8 cells did not affect cell proliferation but caused an inhibitory effect on cell migration in vitro. In vivo analysis showed that N-cadherin- and cadherin-11-overexpressing cells exhibited a marked reduction in their ability to form pulmonary metastases, with significant decreases in lung weight and the number and weight of metastatic lesions, as well as the size and weight of primary lesions at the s.c.-inoculated site. These observations demonstrate that disruption of N-cadherin- and cadherin-11-mediated cell-cell adhesion is critical in the pulmonary metastasis of osteosarcoma.

Osteogenic sarcoma of the rib: a case presentation and literature review

STUDY DESIGN

A case report is presented.

OBJECTIVES

Primary tumors of the rib are relatively uncommon in the adult population, and even more rare in children. A case of osteogenic sarcoma of the rib and a literature review are presented.

SUMMARY OF BACKGROUND DATA

Osteogenic sarcoma represents approximately 30% of all malignant sarcomas diagnosed in the United States. A single case of osteogenic sarcoma of the rib has been reported in the literature involving a 9-year-old child.

METHODS

Clinical data analysis.

RESULTS

A 9-year-old white boy presented with a mass of the left posterior thorax. The initial chest radiograph showed a nonhomogeneous mass with calcifications adjacent to the 11th rib. The final diagnosis was osteogenic sarcoma. Chemotherapy was initiated. The patient underwent radical excision of the mass. Given the extent of the patient's resection, it was thought that he would be at high risk for the development of spinal deformity. He was placed in a TLSO brace (Bolt Systems, Orlando, FL) and followed closely. At 15 months after excision of his tumor, he was noted to have progression of a thoracolumbar scoliosis and significant kyphosis. At this writing, it has been 52 months since resection. The patient has no evidence of local recurrence or metastatic disease, and his spinal curvature remains stable.

CONCLUSIONS

The patient's short-term (4-year) disease-free survival illustrates the efficacy of neoadjuvant chemotherapy and radical surgical resection. Patients with osteogenic sarcoma of the rib should be monitored closely for the development of spinal deformity if the required resection includes the vertebral column. Casting and bracing may help to limit progression of the deformity.

Inhibition of proliferation in human MNNG/HOS osteosarcoma and SK-ES-1 Ewing sarcoma cell lines in vitro and in vivo by antagonists of growth hormone-releasing hormone: effects on insulin-like growth factor II

BACKGROUND

Antagonists of growth hormone-releasing hormone (GH-RH) can inhibit the proliferation of various tumors either indirectly through the suppression of the pituitary growth hormone/hepatic insulin-like growth factor I (IGF-I) axis and the lowering of serum IGF-I concentration or directly by reducing the levels of IGF-I and IGF-II and their mRNA expression in tumors and blocking the effect of autocrine GH-RH. In this study, the authors investigated the effects of the GH-RH antagonist JV-1-38 on MNNG/HOS human osteosarcoma and SK-ES-1 human Ewing sarcoma cell lines.

METHODS

Male nude mice bearing subcutaneous xenografts of MNNG/HOS or SK-ES-1 tumors were treated subcutaneously with JV-1-38 at a dose of 20 microg twice daily for 4 weeks. The concentrations of IGF-I and IGF-II in serum and in tumor tissue were measured by radioimmunoassay. Tumor and liver levels of mRNA for IGF-I and IGF-II were determined by reverse transcriptase-polymerase chain reaction analysis. The effects of JV-1-38, IGF-I, and IGF-II on cell proliferation in vitro were evaluated.

RESULTS

GH-RH antagonist significantly (P < 0.05) inhibited the tumor volume and tumor weight of MNNG/HOS and SK-ES-1 tumors by > 50% after 4 weeks and increased tumor doubling time. JV-1-38 lowered the serum IGF-I level, decreased the expression of mRNA for IGF-I in the liver, and significantly (P < 0.05-0.01) reduced the concentration of IGF-II and mRNA levels for IGF-II in both sarcomas. The concentration of IGF-I was lowered only in SK-ES-1 tumors. In vitro, the proliferation of SK-ES-1 and MNNG/HOS cells was inhibited by JV-1-38 and by antisera to IGF-I and IGF-II.

CONCLUSIONS

The inhibition of MNNG/HOS osteosarcoma and SK-ES-1 Ewing sarcoma by GH-RH antagonists was linked to a suppression of IGF-II production in tumors. However, in SK-ES-1 tumors, the effects on IGF-I also may be involved.

Clinical and radiographic evaluation of bone tumors

Timely diagnosis of osseous tumors is essential in providing proper management. Appropriate imaging studies are essential to this process, however, if inconclusive, they can be superceded by information obtained through the patient history and physical examination.

Osteosarcomas of flat bones in adolescents and adults

BACKGROUND

Osteosarcomas typically are long bone tumors and rarely affect the flat bones of the axial or appendicular skeleton.

METHODS

The authors examined cases of high grade osteosarcoma of flat bones diagnosed at La Timone Adults University Hospital during a 16-year period.

RESULTS

Sixteen patients with flat bone osteosarcomas were treated between 1980-1997. The median age of the patients was 25 years, with a male-to-female ratio of 14:2. Common presenting symptoms were swelling, pain, or both. Primary therapy included resection (n = 11 patients: alone in 8 patients and with radiation therapy in 3 patients), radiation therapy (n = 2 patients), or no local treatment (n = 3 patients). All patients received polychemotherapy, 7 preoperatively and postoperatively and 9 in the adjuvant setting. The overall 5-year survival rate was 47.7%; the overall median survival was 39 months (range, 4-211 months). The adequate local control rate was 68.7%. The local recurrence rate in patients who benefited from local treatment was 54%. Significant adverse prognostic factors on survival included the presence of synchronous metastases (three patients), metastases at any time during the course of the disease (eight patients), and inadequate local control (five patients). The overriding predictor of survival appeared to be the presence of metastases. Local recurrence appeared to have no influence on survival. No patient with metastases was alive at 3 years, whereas patients without recurrence or with local recurrence alone had a 5-year survival rate of 100%. Because the majority of patients with flat bone osteosarcomas ultimately die of metastatic disease, intensive systematic polychemotherapy should be an important component of treating these tumors.

CONCLUSIONS

Based on the very encouraging results observed in the treatment of long bone osteosarcomas, the therapy for flat bone osteosarcomas should combine radical surgery with preoperative and postoperative adjuvant chemotherapy.

Long-term results after combined modality treatment for non-metastatic osteosarcoma

Since the introduction of multimodality treatment, the prognosis of patients with high-grade non-metastatic osteosarcoma has significantly improved. A retrospective review was performed to assess the long-term results of this approach in a single centre setting, and to investigate the impact of potential clinical prognostic factors. Between 1985 and 1993, 35 patients with stage II-A and II-B osteosarcoma underwent preoperative chemotherapy (high-dose methotrexate), wide surgery, and adjuvant chemotherapy (cisplatin-doxorubicin/bleo-mycin-cyclophosphamide-dactinomycin) (modified T-10A protocol). There were 19 males and 16 females. Median patient age was 17 y (range 12-42). Primary tumour sites were the extremities (83%) and axial bones (17%). In spite of an unfavourable grade 3-4 histologic response rate to high-dose methotrexate of 12%, 31 (88%) patients were able to undergo limb-sparing surgery and 28 (80%) were rendered disease free after the planned therapy. Median follow-up was 8 y. The actuarial overall survival and disease-free survival rates were 64% and 49% at 5 y, and 59% and 49% at 10 y, respectively. Tumour size and primary site were significant prognostic factors for survival in univariate analyses. In conclusion, long-term survival after combined modality treatment can be achieved in more than 60% of patients with localised osteosarcoma, including non-appendicular lesions. Limb-sparing surgery is a realistic goal for most cases. The prognostic value of tumour necrosis and the efficacy of neoadjuvant chemotherapy should be interpreted according to individual high-dose methotrexate scheduling.