The role of high-dose therapy and autologous stem cell transplantation for pediatric bone and soft tissue sarcomas

Autologous peripheral blood stem cell mobilization and apheresis in pediatric patients with cancer: A single-center report of 64 procedures

BACKGROUND

The published experience concerning autologous peripheral blood stem cell collection in children is very limited.

METHODS

The data of pediatric patients who underwent autologous stem cell mobilization and apheresis between January 2011 and April 2020 were analyzed retrospectively.

RESULTS

We studied retrospectively 64 mobilization and apheresis procedures in 48 pediatric patients (34 males, 14 females), mean age of 7.31 ± 5.38 (range, 1.5-19.7) years, the underlying disease was mostly neuroblastoma (NBL). The body weight of 21 patients (43.75%) was 15 kg or less. The targeted autologous peripheral stem cell apheresis (APSCA) was successfully achieved in 98% of patients. Neuroblastoma patients were younger than the rest of the patients and underwent apheresis after receiving fewer chemotherapy cycles than others and all of them mobilized within the first session successfully. Plerixafor was added to mobilization in nine heavily pretreated patients (18.7%), median two doses (range, 1-4 doses). 11 patients (22.9%) underwent radiotherapy (RT) before mobilization with doses of median 24 Gy (range, 10.8-54.0 Gy). Patients with RT were older at the time of apheresis and had received more chemotherapy courses than patients without RT. As a result, patients with a history of RT had significantly lower peripheral CD34+ cells and CD34+ yields than those without RT. In 17 patients (35.4%), 22 different complications were noted. The most common complications were catheter-related infections (n:10, 20.8%), followed by catheter-related thrombosis in eight patients (16.7%).

CONCLUSIONS

Patients who had far less therapy before apheresis were more likely to mobilize successfully. Our study provides a detailed practice approach including complications during APSCA aiming to increase the success rates of apheresis in transplantation centers.

Histologic Response and Toxicity following Interval-Compressed Four-Drug Therapy Given Preoperatively in Children and Young Adults with Osteosarcoma: A Retrospective Study

OBJECTIVES

The histologic response to chemotherapy is an important prognostic factor in osteosarcoma. Thus, we attempted to develop an effective neoadjuvant regimen to achieve an improvement in histologic response.

METHODS

Twenty-nine patients with a high-grade osteosarcoma received 2 courses of neoadjuvant chemotherapy non-randomly with either the MAP regimen (methotrexate 12 g/m2, cisplatin 120 mg/m2, and doxorubicin 75 mg/m2) or MAPI regimen (MAP plus ifosfamide 9 g/m2). We applied interval compression to MAPI by shortening the preoperative period to be aligned with that of MAP. Adjuvant chemotherapy was tailored according to the necrosis rate of resected tumor specimens. Necrosis rate, toxicity, and survival outcome were compared retrospectively between the 2 groups.

RESULTS

The median interval between the beginning of neoadjuvant chemotherapy and surgery was 97.0 days in the MAPI group (17 patients) and 90.5 days in the MAP group (12 patients; p = 0.19). The good histologic response (>90% of necrosis) was observed in 71% of MAPI and in 42% of MAP (p = 0.12). Major toxicities of grade 3 or worse were not different between the 2 groups. The probability of 5-year progression-free survival and overall survival of the MAPI group were 74 and 83%, and those in the MAP group were 50 and 75%, showing no difference.

CONCLUSIONS

Interval-compressed MAPI therapy given in a similar duration of the preoperative phase to that of conventional MAP therapy showed a marginal trend toward a better histologic response without a significant increase in major toxicities. Regarding the proportion of good histologic response, 71% is one of the highest values ever reported in the literature. The results warrant further testing in a prospective way in a larger cohort.

Glaucocalyxin A reverses EMT and TGF-β1-induced EMT by inhibiting TGF-β1/Smad2/3 signaling pathway in osteosarcoma

Metastatic osteosarcoma usually has an unsatisfactory response to the current standard chemotherapy and causes poor prognosis. Currently, epithelial-mesenchymal transition (EMT) is reported as a critical event in osteosarcoma metastasis. Glaucocalyxin A, a bioactive ent-kauranoid diterpenoid, exerts anti-cancer effect on osteosarcoma by inducing apoptosis in previous study. However, the effect of Glaucocalyxin A on EMT and metastasis of osteosarcoma is unclear. In this study, we investigated the potential mechanisms of Glaucocalyxin A on EMT and metastasis of osteosarcoma. We found that Glaucocalyxin A inhibited migration and invasion of MG-63 and 143B cells. Moreover, Glaucocalyxin A increased the protein and mRNA levels of E-cadherin and decreased the protein and transcription expression of N-cadherin, Vimentin. Glaucocalyxin A also inhibited the protein and mRNA levels of EMT-associated transcription factor including Snail and Slug. Furthermore, Glaucocalyxin A inhibited transforming growth factor-β1 (TGF-β1)-induced migration, invasion and EMT of low-metastatic osteosarcoma U2OS cells. Glaucocalyxin A inhibited TGF-β-induced phosphorylation of Smad 2/3 in osteosarcoma U2OS cells. Finally, we established transplanted metastatic models of highly metastatic osteosarcoma 143B cells. Glaucocalyxin A inhibited lung metastasis in vivo. Interestingly, Glaucocalyxin A increased the protein expression of E-cadherin and reduced the protein expression of N-cadherin and Vimentin. Glaucocalyxin A inhibited the protein expression of Snail and Slug in vivo. In summary, this study demonstrated that Glaucocalyxin A inhibited EMT and TGF-β1-induced EMT by inhibiting TGF-β1/Smad2/3 signaling pathway in osteosarcoma. Therefore, Glaucocalyxin A might be a promising candidate against the metastasis of human osteosarcoma.

Oridonin prevents epithelial-mesenchymal transition and TGF-β1-induced epithelial-mesenchymal transition by inhibiting TGF-β1/Smad2/3 in osteosarcoma

Osteosarcoma is the most common primary bone tumor with highly invasive characteristic and low long-term survival. Recently, epithelial-mesenchymal transition (EMT) is reported as a key event in cancer invasion and metastasis. Oridonin, a bioactive diterpenoid, has been proved to possess anti-cancer effects. However, the effect of oridonin on EMT and metastasis of osteosarcoma is unclear. In this study, we investigated the underlying mechanism of oridonin on EMT and metastasis of osteosarcoma. We found that oridonin inhibited migration and invasion of MG-63 and 143B cells. Moreover, oridonin increased the protein expression of E-cadherin and decreased that of N-cadherin and Vimentin. Oridonin upregulated the transcription of E-cadherin and downregulated N-cadherin and Vimentin. Oridonin inhibited the protein and mRNA levels of Snail and Slug. Furthermore, oridonin inhibited TGF-β-induced phosphorylation of Smad 2/3, prevented Smad dimer translocation into the nucleus. Finally, we established metastatic models of osteosarcoma 143B cells, and found that oridonin inhibited lung metastasis in vivo. Oridonin increased the protein expression of E-cadherin and reduced N-cadherin and Vimentin. Oridonin inhibited the protein expression of Snail and Slug as well as Smad 2/3 activation. In conclusion, our study demonstrated that oridonin inhibited EMT and TGF-β1-induced EMT by inhibiting TGF-β1/Smad2/3 signaling pathway in osteosarcoma.

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for nonrhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Nonrhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In people with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity. The rationale for this update is to determine whether any randomized controlled trials (RCTs) have been conducted and to clarify whether HDCT followed by autologous HSCT has a survival advantage.

OBJECTIVES

To assess the efficacy and safety of high-dose chemotherapy (HDCT) followed by autologous hematopoietic stem cell transplantation (HSCT) for all stages of nonrhabdomyosarcoma soft tissue sarcomas (NRSTS) in children and adults.

SEARCH METHODS

For this update, we revised the search strategy to improve the precision and reduce the number of irrelevant hits. We searched the following electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), PubMed from 2012 to 6 September 2016, and Embase from 2012 to 26 September 2016. We searched online trial registries and congress proceedings from 2012 to 26 September 2016.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title or abstract. We restricted the study design to RCTs. We included studies if at least 80% of participants had a diagnosis listed in any version of the World Health Organization (WHO) classification and classified as malignant. The search included children and adults with no age limits.

DATA COLLECTION AND ANALYSIS

We used standard methodologic procedures expected by Cochrane. The primary outcomes were overall survival and treatment-related mortality.

MAIN RESULTS

We identified 1549 records; 85 items from electronic databases, 45 from study registries, and 1419 from congress proceedings. The revised search strategy did not identify any additional RCTs. In the previous version of the review, we identified one RCT comparing HDCT followed by autologous HSCT versus standard-dose chemotherapy (SDCT). The trial randomized 87 participants who were considerably heterogeneous with respect to 19 different tumor entities. The data from 83 participants were available for analysis.In the single included trial, overall survival at three years was 32.7% in the HDCT arm versus 49.4% in the SDCT arm and there was no difference between the treatment groups (hazard ratio (HR) 1.26, 95% confidence interval (CI) 0.70 to 2.29, P = 0.44; 1 study, 83 participants; high quality evidence). In a subgroup of participants who had a complete response before HDCT, overall survival was higher in both treatment groups and overall survival at three years was 42.8% in the HDCT arm versus 83.9% in the SDCT arm and favored the SDCT group (HR 2.92, 95% CI 1.1 to 7.6, P = 0.028; 1 study, 39 participants).In the single included trial, the authors reported one treatment-related leukemia death two years after HDCT. They also evaluated severe adverse events WHO grade 3 to 4 in 22 participants in the HDCT arm and in 51 participants in the SDCT arm. The authors reported 11 events concerning digestive-, infection-, pain-, or asthenia-related toxicity in the HDCT arm and one event in the SDCT arm (moderate quality evidence). The development of secondary neoplasia was not addressed. We judged the study to have an overall unclear risk of bias as three of seven items had unclear and four items had low risk of bias. For GRADE, we judged three items as high quality and three items were not reported.

AUTHORS' CONCLUSIONS

The limited data of a single RCT with an unclear risk of bias and moderate to high quality evidence showed no survival advantage for HDCT. If this treatment is offered it should only be given after careful consideration on an individual person basis and possibly only as part of a well-designed RCT.

Anticancer effect of thalidomide in vitro on human osteosarcoma cells

Osteosarcoma is a high‑grade malignant tumor frequently found in children and adolescents. Thalidomide has been reported for treatment of various malignancies. Thalidomide was added to osteosarcoma cells and studied by cytotoxicity assay, evaluating apoptosis, cell cycle arrest, mitochondrial membrane potential (ΔΨm), and reactive oxygen species (ROS) levels and the expression of Bcl‑2, Bax, caspase‑3 and NF‑κB. The results showed that thalidomide could inhibit the proliferation of MG‑63 and U2OS cells in a concentration‑ and time‑dependent manner. Morphological changes of apoptosis were also observed. Thalidomide increased the apoptosis rate of MG‑63 cells and induced cell cycle arrest by increasing the number of cells in the G0/G1 phase and decreasing the percentage of S phase in MG‑63 cells. Further investigation showed that a disruption of ΔΨm and upregulation of ROS were induced by thalidomide in high concentration. By western blot analysis, thalidomide resulted in the decreasing expression of Bcl‑2 and NF‑κB, and the increasing expression of Bcl‑2/Bax and caspase‑3. Here, we provide evidence that thalidomide could cause apoptosis in osteosarcoma cells. Taken together, these results indicate that thalidomide could be an antitumor drug in the therapy of osteosarcoma.

Comparison of two apheresis systems for autologous stem cell collections in pediatric oncology patients

BACKGROUND

Peripheral stem cell collections can be challenging in the pediatric population and respective experience is limited. Since February 2015 our institution is utilizing the new Spectra Optia (Optia) apheresis device, which has replaced the former COBE Spectra (COBE) device. As a quality initiative we collected and compared collection efficiency (CE2) and other collection variables between the two devices.

STUDY DESIGN AND METHODS

In this retrospective study we collected and compared clinical, laboratory, and technical collection data from stem cell collection procedures done with the Optia and COBE devices. The collected data included patient demographics, precollection peripheral CD34+ cell counts, total CD34+ cells collected, complete blood count, electrolytes before and after collection, side effects attributed to the collection, total blood volumes processed (TBVs), collection times, and calculated CE2 and collection ratios.

RESULTS

Forty-one collection procedures performed on 29 pediatric patients with the Optia device were compared to 41 collections performed on 27 patients with the COBE device. The TBVs through the Optia device were significantly smaller than the COBE (3.9 ± 0.2 × TBV vs. 5.5 ± 0.1 × TBV, respectively; p < 0.001), requiring significantly less anticoagulant and providing similar amounts of stem cells while collection times were significantly shorter (mean, 238 ± 9 min vs. 264 ± 9 min, respectively; p < 0.05). Collections on the Optia caused significantly smaller reductions of plasma calcium and magnesium. No significant side effects attributed to the procedure were noted.

CONCLUSION

Stem cell apheresis with the Optia device in children is safe and feasible with smaller blood volumes with shorter collection times.

Nimbolide Induces ROS-Regulated Apoptosis and Inhibits Cell Migration in Osteosarcoma

Osteosarcoma (OS) is a primary malignant tumor of bone and is most prevalent in children and adolescents. OS is frequently associated with pulmonary metastasis, which is the main cause of OS-related mortality. OS has a poor prognosis and is often unresponsive to conventional chemotherapy. In this study, we determined that Nimbolide, a novel anti-cancer therapy, acts by modulating multiple mechanisms in osteosarcoma cells. Nimbolide induces apoptosis by increasing endoplasmic reticulum (ER) stress, mitochondrial dysfunction, accumulation of reactive oxygen species (ROS), and finally, caspase activation. We also determined that Nimbolide inhibits cell migration, which is crucial for metastasis, by reducing the expression of integrin αvβ5. In addition, our results demonstrate that integrin αvβ5 expression is modulated by the PI3K/Akt and NF-κB signaling cascade. Nimbolide has potential as an anti-tumor drug given its multifunctional effects in OS. Collectively, these results help us to understand the mechanisms of action of Nimbolide and will aid in the development of effective therapies for OS.

Depression of focal adhesion kinase induces apoptosis in rat osteosarcoma OSR-6 cells in a caspase-dependent pathway

Focal adhesion kinase (FAK), a nonreceptor tyrosine kinase protein, acts as an early modulator of integrin signaling cascade, regulating basic cellular functions. In transformed cells, unopposed FAK signaling has been considered to promote tumor growth, progression, and metastasis. The aim of this study was to assess the role of FAK in rat osteosarcoma OSR-6 cells. OSR-6 cells were transfected with PGPU6/GFP/shNC (shNC), and PGPU6/GFP/FAK-2434 (shRNA-2434), separately. Expression of FAK was detected by Real-time PCR and Western blots. MTT assay was used to examine changes in cell proliferation. Cell apoptosis was analyzed by flow cytometry. The expression of caspase-3,-7,-9 was measured by Western blots. The expression of FAK in OSR-6 cells significantly decreased in shRNA-2434 group in contrast to the control group (P < 0.01). Cell proliferation was inhibited by shRNA-2434 and shRNA-2434+ cisplatin, and the effects were clearly enhanced when cells were treated with anticancer agents. The level of cell apoptosis in shRNA-2434 and shRNA-2434+ cisplatin group was higher than that in the control group (P < 0.01). The current data support evidence that down-regulation of FAK could induce rat osteosarcoma cells (OSR-6) apoptosis through the caspase-dependent cell death pathway. Inhibition of the kinases may be important for therapies designed to enhance the apoptosis in osteosarcoma.

Cyr61 promotes epithelial-mesenchymal transition and tumor metastasis of osteosarcoma by Raf-1/MEK/ERK/Elk-1/TWIST-1 signaling pathway

Background

Osteosarcoma is the most common primary malignant tumor in children and young adults, and its treatment requires effective therapeutic approaches because of a high mortality rate for lung metastasis. Epithelial to mesenchymal transition (EMT) has received considerable attention as a conceptual paradigm for explaining the invasive and metastatic behavior during cancer progression. The cysteine-rich angiogenic inducer 61 (Cyr61) gene, a member of the CCN gene family, is responsible for the secretion of Cyr61, a matrix-associated protein that is involved in several cellular functions. A previous study showed that Cyr61 expression is related to osteosarcoma progression. In addition, Cyr61 could promote cell migration and metastasis in osteosarcoma. However, discussions on the molecular mechanism involved in Cyr61-regulated metastasis in osteosarcoma is poorly discussed.

Results

We determined that the expression level of Cyr61 induced cell migration ability in osteosarcoma cells. The Cyr61 protein promoted the mesenchymal transition of osteosarcoma cells by upregulating mesenchymal markers (TWIST-1 and N-cadherin) and inhibiting the epithelial marker (E-cadherin). Moreover, the Cyr61-induced cell migration was mediated by EMT. The Cyr61 protein elicited a signaling cascade that included αvβ5 integrin, Raf-1, mitogen-activated protein kinase (MEK), extracellular signal-regulated kinase (ERK), and Elk-1. The reagent or gene knockdown of these signaling proteins could inhibit Cyr61-promoted EMT in osteosarcoma. Finally, the knockdown of Cyr61 expression obviously inhibited cell migration and repressed mesenchymal phenotypes, reducing lung metastasis.

Conclusion

Our results indicate that Cyr61 promotes the EMT of osteosarcoma cells by regulating EMT markers via a signal transduction pathway that involves αvβ5 integrin, Raf-1, MEK, ERK, and Elk-1.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-236) contains supplementary material, which is available to authorized users.

Bufalin inhibited the growth of human osteosarcoma MG-63 cells via down-regulation of Bcl-2/Bax and triggering of the mitochondrial pathway

Cinobufacini (Huachansu), a Chinese medicine prepared from the skin of Bufo bufo gargarizans Cantor (Bufonidae), has potent anti-tumor activity in vitro and in vivo. However, the molecular mechanism of cell apoptosis induced by Bufalin remains elusive. Here, we investigated the apoptosis in Bufalin-treated human osteosarcoma MG-63 cells. The results showed that Bufalin could inhibit cell proliferation and induce apoptosis in a dose- and time-dependent manner. Further investigation revealed that a disruption of mitochondrial transmembrane potential (MMP) and an up-regulation of reactive oxygen species (ROS) in Bufalin-treated cells. By western blot analysis, we found that the up-regulation of Apaf-1, cleaved PARP, cleaved caspase-3, cleaved caspase-9, and Bax/Bcl-2, varies with different concentration of Bufalin. These protein interactions may play a pivotal role in the regulation of apoptosis. Taken together, these results overall indicate that Bufalin could be used as an effective anti-tumor agent in therapy of osteosarcoma targets the mitochondrial-dependent signaling pathway.

Up-regulated isocitrate dehydrogenase 1 suppresses proliferation, migration and invasion in osteosarcoma: in vitro and in vivo

Very few studies have been reported the function of wild type IDH1 in tumor progress. Previously, we reported that IDH1 correlated with pathological grade and metastatic potential inversely in human osteosarcoma. Here, IDH1 was found lower expressed in osteosarcoma tissues than that of adjacent normal bone tissues. In addition, we observed in vitro anti-proliferation and pro-apoptosis effects of up-regulated IDH1 on osteosarcoma cell lines. The migration and invasion activity was also markedly reduced by IDH1 up-regulation. Unexpectedly, IDH1 up-regulation also suppressed tumor growth and metastasis in vivo. Therefore, IDH1 may represent a potential novel treatment and preventive strategy for osteosarcoma.

Inhibition of focal adhesion kinase induces apoptosis in human osteosarcoma SAOS-2 cells

Focal adhesion kinase (FAK), a non-receptor tyrosine kinase protein, acts as an early modulator of integrin signaling cascade, regulating basic cellular functions. In transformed cells, unopposed FAK signaling has been considered to promote tumor growth, progression, and metastasis. The aim of this study was to assess the role of focal adhesion kinase in human osteosarcoma SAOS-2 cells. SAOS-2 cells were transfected with PGPU6/GFP/shNC, and PGPU6/GFP/FAK-334 (shRNA-334), respectively. Expression of FAK was detected by real-time PCR and western blots. MTT assay was used to examine changes in cell proliferation. Cell apoptosis was analyzed by flow cytometry. The expression of caspase-3,-7,-9 was measured by Western blots. The expression of FAK in SAOS-2 cells significantly decreased in shRNA-334 group contrast to the control group (P < 0.01). Cells proliferation was inhibited by shRNA-334 and shRNA-334 + cisplatin, and the effects were clearly enhanced when cells treated with the anticancer agents. The level of cell apoptosis in shRNA-334 and shRNA-334 + cisplatin group was higher than in the control group (P < 0.01). The current data support evidence that down-regulation of FAK could induce SAOS-2 apoptosis through the caspase-dependent cell death pathway. Inhibition of the kinases may be important for therapies designed to enhance the apoptosis in osteosarcoma.

Autologous hematopoietic stem cell transplantation following high dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity. The rationale for this update is to determine whether any randomized controlled trials (RCTs) have been conducted and to clarify whether HDCT followed by autologous HSCT has a survival advantage.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) in children and adults.

SEARCH METHODS

For this update we modified the search strategy to improve the precision and reduce the number of irrelevant hits. All studies included in the original review were considered for re-evaluation in the update. We searched the electronic databases CENTRAL (2012, Issue 11) in The Cochrane Library , MEDLINE and EMBASE (05 December 2012) from their inception using the newly developed search strategy. Online trials registers and reference lists of systematic reviews were searched.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title or abstract. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Single-arm studies were included in addition to studies with a control arm because the number of comparative studies was expected to be very low.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted study data. Some studies identified in the original review were re-examined and found not to meet the inclusion criteria and were excluded in this update. For studies with no comparator group, we synthesized the results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM).

MAIN RESULTS

The selection process was carried out from the start of the search dates for the update. We included 57 studies, from 260 full text articles screened, reporting on 275 participants that were allocated to HDCT followed by autologous HSCT. All studies were not comparable due to various subtypes. We identified a single comparative study, an RCT comparing HDCT followed by autologous HSCT versus standard chemotherapy (SDCT). The overall survival (OS) at three years was 32.7% versus 49.4% with a hazard ratio (HR) of 1.26 (95% confidence interval (CI) 0.70 to 2.29, P value 0.44) and thus not significantly different between the treatment groups. In a subgroup of patients that had a complete response before treatment, OS was higher in both treatment groups and OS at three years was 42.8% versus 83.9% with a HR of 2.92 (95% CI 1.1 to 7.6, P value 0.028) and thus was statistically significantly better in the SDCT group. We did not identify any other comparative studies. We included six single-arm studies reporting aggregate data of cases; three reported the OS at two years as 20%, 48%, and 51.4%. One other study reported the OS at three years as 40% and one further study reported a median OS of 13 months (range 3 to 19 months). In two of the single-arm studies with aggregate data, subgroup analysis showed a better OS in patients with versus without a complete response before treatment. In a survival analysis of pooled individual data of 80 participants, OS at two years was estimated as 50.6% (95% CI 38.7 to 62.5) and at three years as 36.7% (95% CI 24.4 to 49.0). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. The one included RCT had a low risk of bias and the remaining 56 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

A single RCT with a low risk of bias shows that OS after HDCT followed by autologous HSCT is not statistically significantly different from standard-dose chemotherapy. Therefore, HDCT followed by autologous HSCT for patients with NRSTS may not improve the survival of patients and should only be used within controlled trials if ever considered.

Matrine inhibited the growth of rat osteosarcoma UMR-108 cells by inducing apoptosis in a mitochondrial-caspase-dependent pathway

Matrine, one of the main active components of the extracts from the dry roots of Sophora flavescens, has a potent antitumor activity in vitro and in vivo. However, the molecular mechanism of cell apoptosis induced by matrine remains elusive. Here, we investigated the apoptosis in matrine-treated rat osteosarcoma UMR-108 cells. The results showed that matrine could inhibit cell proliferation and induce apoptosis in a dose- and time-dependent manner. Further investigation revealed a disruption of mitochondrial transmembrane potential and an upregulation of reactive oxygen species in matrine-treated cells. By western blot analysis, we found the upregulation of cleaved poly(ADP-ribose) polymerase, cleaved caspase-3, and cleaved caspase-9 and the downregulation of Bax/Bcl-2 with different concentrations of matrine. These protein interactions may play a pivotal role in the regulation of apoptosis. Taken together, these results overall indicate that matrine could be used as an effective antitumor agent in therapy of osteosarcoma targets the caspase-dependent signaling pathway.

Interleukin-6 induces vascular endothelial growth factor expression and promotes angiogenesis through apoptosis signal-regulating kinase 1 in human osteosarcoma

Osteosarcoma is characterized by a high malignant and metastatic potential. Angiogenesis is essential for the caner metastasis. Interleukin-6 (IL-6) is a multifunctional cytokine that is associated with the disease status and outcomes of cancers. However, the relationship between IL-6 and vascular endothelial growth factor (VEGF) expression in human osteosarcoma is mostly unknown. Here we found that the IL-6 and VEGF expression was correlated with tumor stage and significantly higher than that in normal bone. Incubation of osteosarcoma cells with IL-6 increased VEGF mRNA and protein expression. Pretreatment of cells with IL-6R antibody reduced IL-6-mediated VEGF production. The apoptosis signal-regulating kinase 1 (ASK1)/p38/AP-1 pathway was activated after IL-6 treatment, and IL-6-induced VEGF expression was abolished by the specific inhibitor and siRNA of ASK1, p38, and AP-1 cascades. Importantly, knockdown IL-6 reduced VEGF expression and abolished osteosarcoma conditional medium-mediated angiogenesis. Taken together, these results indicate that IL-6 occurs through ASK1 and p38, which in turn activates AP-1, resulting in the activations of VEGF expression and contributing the angiogenesis of human osteosarcoma cells.

Clinical results of high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation in children with advanced stage rhabdomyosarcoma

Regardless of improvement in cure of Rhabdomyosarcoma (RMS), the results in treatment of advanced stage of RMS in children are still dismal. Recently, high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (HDC/APBSCT) has been tried to manage the advanced high-risk RMS patients. We investigated the effectiveness of HDC/APBSCT by reviewing the clinical records of high-risk pediatric RMS patients in single institute database. Over twenty years, 37 patients were diagnosed as RMS with high-risk at the time of first diagnosis. These patients were classified as two groups according to treatment method. The first group was HDC/APBSCT and the other was conventional multi-agent chemotherapy group. Differences of clinical results between the two groups were analyzed. The median age of patients was 5 yr, ranging from 6 months to 15 yr. The 5-yr event free survival rate (EFS) of all patients was 24.8% ± 4.8%. HDC/APBSCT group and conventional multi-agent chemotherapy group were 41.3% ± 17.8% and 16.7% ± 7.6% for 5-yr EFS, respectively (P = 0.023). There was a significant difference in the result of HDC/APBSCT between complete remission or very good partial response group and poor response group (50% ± 20.4% vs 37.5% ± 28.6%, P = 0.018). HDC/APBSCT can be a promising treatment modality in high-risk RMS patients.

CCL5 and CCR5 interaction promotes cell motility in human osteosarcoma

BACKGROUND

Osteosarcoma is characterized by a high malignant and metastatic potential. CCL5 (previously called RANTES) was originally recognized as a product of activated T cells, and plays a crucial role in the migration and metastasis of human cancer cells. It has been reported that the effect of CCL5 is mediated via CCR receptors. However, the effect of CCL5 on migration activity and integrin expression in human osteosarcoma cells is mostly unknown.

METHODOLOGY/PRINCIPAL FINDINGS

Here we found that CCL5 increased the migration and expression of αvβ3 integrin in human osteosarcoma cells. Stimulation of cells with CCL5 increased CCR5 but not CCR1 and CCR3 expression. CCR5 mAb, inhibitor, and siRNA reduced the CCL5-enhanced the migration and integrin up-regulation of osteosarcoma cells. Activations of MEK, ERK, and NF-κB pathways after CCL5 treatment were demonstrated, and CCL5-induced expression of integrin and migration activity was inhibited by the specific inhibitor and mutant of MEK, ERK, and NF-κB cascades. In addition, over-expression of CCL5 shRNA inhibited the migratory ability and integrin expression in osteosarcoma cells.

CONCLUSIONS/SIGNIFICANCE

CCL5 and CCR5 interaction acts through MEK, ERK, which in turn activates NF-κB, resulting in the activations of αvβ3 integrin and contributing the migration of human osteosarcoma cells.

Reduced-intensity allogeneic stem cell transplantation in children and young adults with ultrahigh-risk pediatric sarcomas

Some subsets of pediatric sarcoma patients have very poor survival rates. We sought to determine the feasibility and efficacy of allogeneic hematopoietic stem cell transplantation (alloHSCT) in pediatric sarcoma populations with <25% predicted overall survival (OS). Patients with ultrahigh-risk Ewing's sarcoma family of tumors (ESFT), alveolar rhabdomyosarcoma, or desmoplastic small round cell tumors received EPOCH-fludarabine induction, a cyclophosphamide/fludarabine/melphalan preparative regimen, and HLA matched related peripheral blood stem cells. Thirty patients enrolled; 7 did not undergo alloHSCT because of progressive disease with diminishing performance status during induction. All 23 alloHSCT recipients experienced rapid full-donor engraftment, with no peritransplantation mortality. Five of 23 alloHSCT recipients (22%) remain alive (OS of 30% by Kaplan-Meier analysis at 3 years), including 3 of 7 (42%) transplanted without overt disease (median survival 14.5 versus 29.0 months from alloHSCT for patients transplanted with versus without overt disease, respectively). Among the 28 patients who progressed on the study, the median survival from date of progression was 1.9 months for the 7 who did not receive a transplant compared with 11.4 months for the 21 transplanted (P = .0003). We found prolonged survival after posttransplantation progression with several patients exhibiting indolent tumor growth. We also saw several patients with enhanced antitumor effects from posttransplantation chemotherapy (objective response to pretransplantation EPOCH-F was 24% versus 67% to posttransplantation EOCH); however, this was associated with increased toxicity. This largest reported series of alloHSCT in sarcomas demonstrates that alloHSCT is safe in this population, and that patients undergoing alloHSCT without overt disease show higher survival rates than reported using standard therapies. Enhanced chemo- and radiosensitivity of tumors and normal tissues was observed posttransplantation.

Matrine induces caspase-dependent apoptosis in human osteosarcoma cells in vitro and in vivo through the upregulation of Bax and Fas/FasL and downregulation of Bcl-2

PURPOSE

Matrine, one of the main active components of extracts from the dry roots of Sophora flavescens, has potent anti-tumor activity in various cancer cell lines. However, the activity of matrine against osteosarcoma remains unclear. In the present study, we examined the effects of matrine on human osteosarcoma cells and explored the underlying mechanism.

METHODS

Four human osteosarcoma cell lines: MG-63, U-2OS, Saos-2, and MNNG/HOS were treated by matrine and subjected to MTT assay, annexin V-FITC/PI double staining, and TUNEL assay. The activation of caspases and the expression of pro-apoptotic and anti-apoptotic factors were examined by qRT-PCR and Western blot. In addition, MNNG/HOS xenograft tumors were established in female nude BALB/c mice, and matrine was intraperitoneally (i.p.) administered to evaluate the anti-cancer capacity of matrine in vivo.

RESULTS

We found that matrine inhibited the proliferation and induced apoptosis of the four osteosarcoma cell lines in vitro and induced the activation of caspase-3, -8, and -9 in a dose-dependent manner. Furthermore, the pro-apoptotic factors Bax and Fas/FasL were upregulated, and the anti-apoptotic Bcl-2 was downregulated. More importantly our in vivo, studies showed that administration of matrine decreased tumor growth in a dose-dependent manner. Immunohistochemistry analysis demonstrated the downregulation of Bcl-2 and upregulation of Bax and Fas/FasL in MNNG/HOS tumor tissues following matrine treatment, consistent with the in vitro results.

CONCLUSION

Our results demonstrate that matrine inhibits the proliferation and induces apoptosis of human osteosarcoma cells in vitro and in vivo. The induction of apoptosis appears to occur through the upregulation of Fas/FasL and Bax, downregulation of Bcl-2, and activation of caspase-3, -8, and -9, which then trigger major apoptotic cascades.

High-dose chemotherapy followed by autologous stem cell transplantation for metastatic rhabdomyosarcoma--a systematic review

INTRODUCTION

Patients with metastatic rhabdomyosarcoma (RMS) have a poor prognosis. The aim of this systematic review is to investigate whether high-dose chemotherapy (HDCT) followed by autologous hematopoietic stem cell transplantation (HSCT) in patients with metastatic RMS has additional benefit or harm compared to standard chemotherapy.

METHODS

Systematic literature searches were performed in MEDLINE, EMBASE, and The Cochrane Library. All databases were searched from inception to February 2010. PubMed was searched in June 2010 for a last update. In addition to randomized and non-randomized controlled trials, case series and case reports were included to complement results from scant data. The primary outcome was overall survival. A meta-analysis was performed using the hazard ratio as primary effect measure, which was estimated from Cox proportional hazard models or from summary statistics of Kaplan Meier product-limit estimations.

RESULTS

A total of 40 studies with 287 transplant patients with metastatic RMS (age range 0 to 32 years) were included in the assessment. We identified 3 non-randomized controlled trials. The 3-year overall survival ranged from 22% to 53% in the transplant groups vs. 18% to 55% in the control groups. Meta-analysis on overall survival in controlled trials showed no difference between treatments. Result of meta-analysis of pooled individual survival data of case series and case reports, and results from uncontrolled studies with aggregate data were in the range of those from controlled data. The risk of bias was high in all studies due to methodological flaws.

CONCLUSIONS

HDCT followed by autologous HSCT in patients with RMS remains an experimental treatment. At present, it does not appear justifiable to use this treatment except in appropriately designed controlled trials.

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of soft tissue sarcomas in children and adults.

SEARCH STRATEGY

We searched the electronic databases CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE and EMBASE (February 2010). Online trial registers, congress abstracts and reference lists of reviews were searched and expert panels and authors were contacted.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title, abstract or keywords. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Comparative non-randomized studies were included because randomized controlled trials (RCTs) were not expected. Case series and case reports were considered for an additional descriptive analysis.

DATA COLLECTION AND ANALYSIS

Study data were recorded by two review authors independently. For studies with no comparator group, we synthesised results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM).

MAIN RESULTS

We included 54 studies, from 467 full texts articles screened (11.5%), reporting on 177 participants that received HSCT and 69 participants that received standard care. Only one study reported comparative data. In the one comparative study, OS at two years after HSCT was estimated as statistically significantly higher (62.3%) compared with participants that received standard care (23.2%). In a single-arm study, the OS two years after HSCT was reported as 20%. In a pooled analysis of the individual data of 54 participants, OS at two years was estimated as 49% (95% CI 34% to 64%). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. All 54 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

Due to a lack of comparative studies, it is unclear whether participants with NRSTS have improved survival from autologous HSCT following HDCT. Owing to this current gap in knowledge, at present HDCT and autologous HSCT for NRSTS should only be used within controlled trials.

Microarray: an instrument for cancer surgeons of the future?

Microarray enables the study of thousands of genes simultaneously. While still in its infancy as a technique and with a number of barriers to be overcome, microarray is allowing scientists to thoroughly examine the molecular pathways of cancer pathogenesis. However, the adoption of microarray as a clinically applicable technique has been slow coming. Current literature suggests roles in the diagnosis of tumours of unknown origin, in the evaluation of prognostic markers, and in guiding treatment for recurrent and resistant malignancy. This review outlines the science of microarray and draws on clinical examples, including osteosarcoma, breast, prostate and pancreatic carcinomas, to highlight the potential of microarray as a technique of surgical importance.

Nephroblastoma overexpressed gene (NOV) enhances cell motility and COX-2 upregulation of human osteosarcoma involves αvβ5 integrin, ILK and AP-1-dependent pathways

Osteosarcoma is characterized by a high malignant and metastatic potential. Cyclooxygenase (COX)-2, the inducible isoform of prostaglandin synthase, has been implicated in tumor metastasis. Nephroblastoma overexpressed gene (NOV), also called CCN3, was regulated proliferation and differentiation of cancer cells. However, the effect of NOV on migration activity and COX-2 expression in human osteosarcoma cells is mostly unknown. Here we found that NOV increased the migration and expression of COX-2 in human osteosarcoma cells. αvβ5 monoclonal antibody (mAb), integrin-linked kinase (ILK) and Akt inhibitor reduced the NOV-enhanced the migration and COX-2 up-regulation of osteosarcoma cells. NOV stimulation increased the ILK kinase activity and phosphorylation of Akt. In addition, c-Jun siRNA also antagonized the NOV-mediated migration and COX-2 expression. Moreover, NOV enhanced the AP-1 binding activity and promoter activity. Taken together, these results suggest that the NOV acts through αvβ5 integrin to activate ILK and Akt, which in turn activates c-Jun and AP-1, resulting in the activations of COX-2 and contributing the migration of human osteosarcoma cells.

Evaluation of protein pigment epithelium-derived factor (PEDF) and microvessel density (MVD) as prognostic indicators in breast cancer

PURPOSE

Angiogenesis, which plays an important role in tumor growth and metastasis, is regulated by a balance between angiogenic stimulators and inhibitors. Pigment epithelium-derived factor (PEDF), a secreted glycoprotein is an important inhibitor of angiogenesis. Although the precise mechanisms by which PEDF exerts its actions remain poorly understood, there is growing evidence supporting the role of PEDF as a candidate antitumor agent. In this study, we investigated the role of PEDF in breast cancer.

METHODS

We investigated the correlation of PEDF protein levels with cancer progression and prognosis in patients with invasive ductal breast cancer (IDC). We used immunohistochemistry in a cohort of 119 breast cancer patients to examine the expression of PEDF protein with an anti-PEDF antibody and to measure the microvessel density (MVD) with an anti-CD34 antibody.

RESULTS

PEDF was an endogenous inhibitor of angiogenesis in endothelial cells. Decreased intratumoral expression of PEDF was associated with a higher microvessel density (MVD), a more metastatic phenotype, and poorer clinical outcome. PEDF was positive in 43.7% patients. Patients with low PEDF expression had a significantly higher MVD count when compared with patients with high PEDF expression. In univariate and multivariate analysis, PEDF was an independent prognostic factor.

CONCLUSION

The inverse correlation between PEDF expression and MVD in human breast cancer suggests that low PEDF expression is associated with angiogenesis in breast cancer. PEDF expression is therefore a potentially useful prognostic marker for breast cancer.

Feasibility of sequential high-dose chemotherapy in advanced pediatric solid tumors

The purpose of this study was to evaluate the feasibility and tumor response of 3 cycles of sequential high-dose chemotherapy (HDCT) in advanced pediatric solid tumor patients. Medical records of 11 children who underwent 2 consequent courses of reduced conditioning HDCT followed by final HDCT with autologous HSC infusion were reviewed in a retrospective manner. Each median time to an absolute neutrophil count > 0.5 x 10(9)/L was 12, 13, and 12 days. Major toxic reactions were fever, infection, and vomiting. One patient experienced transplantation-related mortality. Nine patients showed complete and partial responses to the therapy at 6 months follow-up after final HDCT. Finally, 6 patients are alive without evidence of disease at median follow-up of 24 months. Even though it is a preliminary result, the authors think that this treatment could be a feasible treatment option for advanced pediatric solid tumor patients.

In vitro and in vivo biological activity of PEDF against a range of tumors

BACKGROUND

Pigment epithelium-derived factor (PEDF) is an emerging anti-cancer agent that targets both tumor tissue and its supporting vasculature. These direct and indirect effects of PEDF have been examined in vitro and in vivo for a range of malignancies.

OBJECTIVE

This review seeks to present PEDF as a potential anti-cancer agent with applications across multiple malignancies. We refer closely to experimental methodology whilst still highlighting the clinical significance of PEDF in cancer, drawing on biological findings in vitro and in vivo.

METHODS

A Pubmed database search was performed limiting the scope of this discussion paper mainly to PEDF's biological role in cancer, specifically lung, breast, prostatic, ovarian and pancreatic carcinomas, melanoma, glioma and osteosarcoma.

CONCLUSIONS

The biological roles of PEDF are diverse and multidimensional. As an anti-cancer agent, PEDF has great potential as a focused anti-neoplastic therapy against a variety of tumor types.

Non-viral methods for gene transfer towards osteosarcoma therapy

Osteosarcoma, a class of cancer that originates from bone, afflicts mainly young people usually in their teenage years of life. Despite surgery and chemotherapy, the outlook for sufferers is not that positive, with a third of patients with metastatic disease not surviving past the 10-year mark. Like other neoplasms, other forms of therapeutics are being evaluated, and amongst these is gene therapy. This review discusses approaches for gene therapy of osteosarcoma using cationic liposomes and polyethylenimine in vivo. The field is still in its infancy as far as osteosarcoma is concerned and much more needs to be done to test its true potential as a feasible therapeutic modality.

DDTD, an isoflavone derivative, induces cell apoptosis through the reactive oxygen species/apoptosis signal-regulating kinase 1 pathway in human osteosarcoma cells

Osteosarcoma is the most common primary bone tumor associated with childhood and adolescence. In the present study, we investigated the anticancer effect of a new isoflavone derivative, 3',4'-dichloro-3-(3,4-dichlorophenylacetyl)-2,4,6-trihydroxydeoxybenzoin (DDTD) in human osteosarcoma cells. DDTD induced cell apoptosis in human osteosarcoma cell lines (including: U2OS, MG-63, Saos2 and ROS 17/2.8). We found that the accumulation of reactive oxygen species is a critical mediator in DDTD-induced cell death. DDTD induced apoptosis signal-regulating kinase 1 (ASK1) dephosphorylation and its dissociation from 14-3-3. Treatment of osteosarcoma cells with DDTD induced p38 and p53 phosphorylation. Transfection with ASK1, mitogen activated protein kinase (MAPK) kinase (MKK)3/6, and p38 small interfering RNA (siRNA) antagonized the DDTD-induced cell apoptosis. DDTD also triggered the mitochondrial apoptotic pathway, as indicated by a change in Bax/Bcl2 ratio and Caspase-9 activation. Bax knockdown using a Bax siRNA strategy reduced Bax expression and subsequent cell death. In addition, transfection of cells with ASK1, MKK3/6, and p38 siRNA reduced DDTD-induced p38 activation, p53 phosphorylation and Bax expression. These results suggest that DDTD generates reactive oxygen species and activates the ASK1-MKK3/6-p38-p53-Bax pathway to cause osteosarcoma cell death.

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.

Ewing sarcoma: prognostic criteria, outcomes and future treatment

Ewing sarcoma (EWS) is a bone tumor occurring primarily in adolescence and young adulthood. Multi-institutional clinical trials have improved the outcome for patients with nonmetastatic EWS, but not with metastatic EWS. Furthermore, although 30% of EWS recur, multi-institutional studies have not been completed for this high-risk group. Planning such studies has been hampered by both the lack of novel therapies and the inability to incorporate the biology of EWS. While the importance and detail of the EWS-FLI-1 translocation between chromosomes 11 and 22 are described, these have not yet led to new drug development for this orphan tumor. However, recent evidence supporting novel cytotoxic therapy, antiangiogenic therapy, and receptor-targeted therapy provides reason for optimism for patients with high-risk disease.

Zoledronic acid inhibits osteosarcoma growth in an orthotopic model

Zoledronic acid (ZOL) has been shown to reduce osteolysis in bone metastasis. Its efficacy in osteosarcoma has not been convincingly proved in a clinically relevant model for the disease. In vitro, ZOL decreased osteosarcoma cell proliferation, mainly due to an increase in apoptosis in a dose-dependent fashion. There was a decrease in cell migration at >or=10 micromol/L concentrations, but invasion was inhibited at a much lower dose of 0.1 micromol/L. Reverse transcription-PCR showed that ZOL overall caused an increased expression of osteocalcin and decreased expression of alkaline phosphatase, osteopontin, osteonectin, and vascular endothelial growth factor, with no change in expression of osteoprotegerin. ZOL administration s.c. twice weekly at 0.12 mg/kg to SaOS-2 tumor-bearing mice resulted in primary tumor growth inhibition, reduction in lung metastases, and dramatic decrease in osteolysis. Furthermore, in the ZOL cohort, there was a clear reduction in the number of osteoclasts in bone exposed to tumor and a lower tumor vessel density. These data point to the adjuvant potential of ZOL in the management of osteosarcoma not only for its antiosteolytic properties but also for its ability to directly halt tumor cell growth and metastasis via its effects on viability, invasion, differentiation, and angiogenesis.

Inhibition of orthotopic osteosarcoma growth and metastasis by multitargeted antitumor activities of pigment epithelium-derived factor

Osteosarcoma is major cause of cancer-related death in the pediatric age group, and this is due to the development of pulmonary metastases that fail to be eradicated with current treatment regimes. Although there have been significant improvements in the long-term survival of such patients, 25-50% with initially non-metastatic disease, subsequently develop metastases and this remains the major cause of death for these patients. In this study, we report the multimodal activity of pigment epithelium-derived factor (PEDF) in inhibiting osteosarcoma growth, angiogenesis and metastasis. In vitro, we found that administration of recombinant PEDF (rPEDF) on two osteosarcoma cell lines (rat UMR 106-01 and human SaOS-2) significantly reduced tumor cell proliferation and increased apoptosis, as well as decreased cell invasion, angiogenesis, and increased adhesion to collagen type-1. Administration of rPEDF upregulated the mRNA expression of phenotypic osteoblast differentiation markers (ALP, pro-alpha(1) collagen and osteocalcin) in a pre-osteoblastic cell line, UMR 201, and also increased mineralized nodule formation in both UMR 106-01 and SaOS-2. In vivo, rPEDF dramatically suppressed primary osteosarcoma growth and the development of macroscopic pulmonary metastases in an orthotopic model of human osteosarcoma (SaOS-2). Interestingly, no activity was seen in tumors grown subcutaneously, suggesting a paracrine interaction between PEDF and the bone microenvironment. Preliminary pharmacoevaluation studies demonstrated rPEDF stability within media containing serum and osteosarcoma cells, and no gross systemic toxicity was observed in vivo with rPEDF administration. These results suggest that PEDF is emerging as an attractive and clinically appealing drug candidate for the treatment of osteosarcoma.

Chitosan microparticles encapsulating PEDF plasmid demonstrate efficacy in an orthotopic metastatic model of osteosarcoma

The major stumbling block for most therapies against deep-seated disease, including tumours, is inefficient drug delivery. Such a concern is particularly important for osteosarcoma, the predominant form of bone cancer, and the largest cancer of its type in the paediatric age group. Pigment epithelium-derived factor (PEDF) is the most potent anti-angiogenic factor found endogenously in the body, with an increasing number of reports pointing to its direct antitumour activity. In this report, when a plasmid expressing PEDF (pPEDF) was encapsulated within two types of chitosan microparticles, anti-invasion and increased adhesion of the osteosarcoma cell line SaOS-2 was noted. Microparticles were formulated using two methods of complex coacervation and were approximately 400-600 nm in diameter. The plasmids were strongly attached to the particles which were polymorphic in shape as determined by electron microscopy. Preliminary experiments with the green fluorescent protein (GFP) reporter plasmid revealed that cells were efficiently transfected with the particles, with particles outlasting transfection with lipofectamine cationic liposomes at 5 days. In vivo, the better pPEDF microparticle resulted in a decrease in primary tumour growth, reduced bone lysis and reduced establishment of lung metastases in a clinically relevant orthotopic model of osteosarcoma. Thus, this new mode of localised gene delivery may hold promise for molecular therapy of osteosarcoma.

PEDF: a potential molecular therapeutic target with multiple anti-cancer activities

Pigment epithelium-derived factor (PEDF) is an endogenously produced protein that is widely expressed throughout the human body, and exhibits multiple and varied biological activities. Already established as a potent anti-angiogenic molecule, PEDF has recently shown promise as a potential anti-tumour agent, causing both direct and indirect tumour suppression. Here, we explore the unique anti-tumour properties of PEDF and discuss its role as an effective anti-angiogenic, anti-proliferative and pro-differentiation factor. We also discuss the prospects for PEDF therapy and the need for a closer evaluation of issues such as delivery, stability and potential toxicity.