Surgical Strategy and Application of Robotic-Assisted Benign Sacral Neurogenic Tumor Resection

BACKGROUND

Robotic surgery may be advantageous in neurogenic sacral tumor resection but only a few studies reported robotic-assisted neurogenic sacral tumor resection.

OBJECTIVE

To propose a new surgical strategy for robotic-assisted benign sacral neurogenic tumor resection and introduce the ultrasonic osteotomy surgical system in robotic surgery.

METHODS

Twelve patients who had robotic-assisted primary benign sacral neurogenic tumor resection between May 2015 and March 2021 were included. Our surgical strategy divides tumors into 4 types. Type I: Presacral tumors with diameter <10 cm. Type II: Narrow-base tumors involving the sacrum with diameter <10 cm. Type III: Broad-base tumors involving the sacrum with diameter <10 cm. Type IV: Tumors involving sacral nerve roots ≥2 levels and/or with diameter ≥10 cm.

RESULTS

Five type I, 5 type II, and 1 type III patients underwent tumor resection via an anterior approach, and 1 type IV patient via a combined approach. The median operation time, blood loss, and postoperative hospital stay of type I and II were much less than those of type IV. The ultrasonic osteotomy surgical system facilitated osteotomy in 2 type II and 1 type III patients. Eleven patients had total resections, and 1 type III patient had a partial resection. During the follow-up period of 7.9 to 70.9 months (median: 28.5 months), no local recurrences or deaths were noted.

CONCLUSION

With the largest single-center series to our knowledge, this surgical strategy helped to guide robotic-assisted benign sacral neurogenic tumor resection. The ultrasonic osteotomy surgical system was effective for type II and III.

METTL14-mediated epitranscriptome modification of MN1 mRNA promote tumorigenicity and all-trans-retinoic acid resistance in osteosarcoma

Background

Osteosarcoma (OS) is the most common primary malignant bone tumor in adolescents. The molecular mechanism behind OS progression and metastasis remains poorly understood, which limits the effectiveness of current therapies. RNA N⁶-methyladenosine (m⁶A) modification plays a critical role in influencing RNA fate. However, the biological significance of m⁶A modification and its potential regulatory mechanisms in the development of OS remain unclear.

Methods

Liquid chromatography-tandem mass spectrometry (LC-MS/MS), dot blotting, and colorimetric ELISA were used to detect m⁶A levels. Western blotting, quantitative real-time PCR (RT-qPCR) and immunohistochemistry (IHC) were used to investigate METTL14 expression levels. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and transcriptomic RNA sequencing (RNA-seq) were used to screen the target genes of METTL14. RNA pull-down and RNA immunoprecipitation (RIP) assays were conducted to explore the specific binding of target genes and relevant m⁶A “readers”. RNA stability and polysome analysis assays were used to detect the half-lives and translation efficiencies of the downstream genes of METTL14. IHC and clinical data were applied to explore the clinical correlations of METTL14 and its downstream target genes with the prognosis of OS.

Findings

We observed the abundance of m⁶A modifications in OS and revealed that METTL14 plays an oncogenic role in facilitating OS progression. MeRIP-seq and RNA-seq revealed that MN1 is a downstream gene of METTL14. MN1 contributes to tumor progression and all-trans-retinoic acid (ATRA) chemotherapy resistance in OS. Mechanistically, MN1 is methylated by METTL14, specifically in the coding sequence (CDS) regions, and this modification is recognized by the specific m⁶A reader insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) to prevent MN1 mRNA degradation and promote it translation efficiency. IHC showed that MN1 expression was positively correlated with METTL14 and IGF2BP2 expression in OS tissues. The METTL14-IGF2BP2-MN1 panel demonstrated more promising prognostic value for OS patients than any of these molecules individually.

Interpretation

Our study revealed that METTL14 contributes to OS progression and ATRA resistance as an m⁶A RNA methylase by regulating the stability and translation efficiency of MN1 and thus provides both an underlying biomarker panel for prognosis prediction in OS patients.

Funding

This work was supported by the National Natural Science Foundation of China (Grants 81972510 and 81772864).

Cordycepin augments the chemosensitivity of osteosarcoma to cisplatin by activating AMPK and suppressing the AKT signaling pathway

Background

Osteosarcoma is the most common primary bone tumor in children and adolescents. However, some patients with osteosarcoma develop resistance to chemotherapy, leading to a poor clinical prognosis. Hence, effective therapeutic agents that can improve the response to chemotherapy drugs to improve the prognosis of patients with osteosarcoma are urgently needed. Cordycepin has recently emerged as a promising antitumor drug candidate. This study aims to explore the effect of cordycepin in suppressing osteosarcoma in vivo and in vitro and the synergistic effect of cordycepin combined with cisplatin and to demonstrate the underlying molecular mechanism.

Methods

CCK-8 assay was performed to investigate the inhibition effect of cordycepin combined with cisplatin in osteosarcoma cell lines. The colony formation and invasion abilities were measured by colony formation assay and Transwell assay. Osteosarcoma cells apoptosis was detected by flow cytometry. Western blot analysis were used to detect the expression of cell apoptosis-related proteins and AMPK and AKT/mTOR signaling pathway-related proteins. Finally, we performed the in vivo animal model to further explore whether cordycepin and cisplatin exert synergistic antitumor effects.

Results

Notably, we found that treatment with cordycepin inhibited cell proliferation, invasion, and induced apoptosis in osteosarcoma cells in vitro and in vivo. Moreover, the combination of cordycepin and cisplatin led to marked inhibition of osteosarcoma cell proliferation and invasion and promoted osteosarcoma cell apoptosis in vitro and in vivo. Mechanistically, we demonstrated that cordycepin enhanced the sensitivity of osteosarcoma cells to cisplatin by activating AMPK and inhibiting the AKT/mTOR signaling pathway.

Conclusions

In brief, this study provides comprehensive evidence that cordycepin inhibits osteosarcoma cell growth and invasion and induces osteosarcoma cell apoptosis by activating AMPK and inhibiting the AKT/mTOR signaling pathway and enhances the sensitivity of osteosarcoma cells to cisplatin, suggesting that cordycepin is a promising treatment for osteosarcoma.

[Psychological and behavioral functioning of children and adolescents during long-term home-schooling]

Objective: To study the characteristics and risk factors of psychological and behavioral problems of children and adolescents of different ages and genders in long-term home-schooling during the coronavirus disease-2019 pandemic. Further, to provide scientific basis for more targeted psychological intervention and coping strategies in the future. Methods: A cross-sectional survey using an online questionnaire was conducted on students aged 6-16 years old in five representative cities of North (Beijing), East (Shanghai), West (Chongqing), South (Guangzhou) and Middle (Wuhan) in China. In this study, the social behavior and psychological abnormalities which was defined as the positive of any dimension were investigated in multiple dimensions during long-term home-schooling. The influencing factors of psycho-behavioral problems were analyzed by Logistic regression, and the confounding factors were corrected with graded multivariable adjustment. Results: A total of 6 906 valid questionnaires were collected including 3 592 boys and 3 314 girls, of whom 3 626 were children (6-11 years old) and 3 280 were adolescents (12-16 years old). The positive detection rate of psychosocial-behavioral problems were 13.0% (900/6 906) totally, 9.6% (344/3 592) in boys and 16.8% (556/3 314) in girls respectively, and 7.3%(142/1 946) in boys aged 6-11, 14.0%(235/1 680) in girls aged 6-11, 12.3%(202/1 646) in boys aged 12-16, 19.6%(321/1 634) in girls aged 12-16 respectively. There were significant differences between the psychological problems group and the non-psychological problems group in gender, parent-offspring conflict, number of close friends, family income change, sedentary time, homework time, screen exposure time, physical activity, dietary problems (χ²=78.851, 285.264, 52.839, 26.284, 22.778, 11.024, 10.688, 36.814, 70.982, all P<0.01). The most common symptoms in boys aged 6-11 years were compulsive activity, schizoid and depression, in girls aged 6-11 years were schizoid/compulsive activity, hyperactivity and social withdrawal, in boys aged 12-16 years were hyperactivity, compulsive activity and aggressive behavior, and in girls aged 12-16 years were schizoid, anxiety/compulsive activity and depression/withdrawal, respectively. After graded multivariable adjustment, besides the common risk factors, homework time and online study time were the risk factors of 6-11 years old groups [boys OR(95%CI): 1.750 (1.32-2.32), 1.214(1.00-1.47), girls: 1.579(1.25-1.99), 1.222(1.05-1.42), all P<0.05], videogames time were the risk factors of 12-16 years old groups [ boys: 2.237 (1.60-3.13), girls: 1.272 (1.00-1.61), all P<0.05]. Conclusions: Some children and adolescents may have psychological and behavioral problems during long-term home-schooling. The psychological and behavioral manifestations differed in age and gender subgroups, which deserve special attention in each subgroups. Schools, families and specialists should actively provide precise psychological support and comprehensive intervention strategies according to special features and risk factors.

A Novel Method to Treat Progressive Desmoid Tumors Involving Neurovascular Bundles: A Retrospective Cohort Study

BACKGROUND

More effective therapies are needed to treat progressive desmoid tumors when active surveillance and systemic therapy fail.

OBJECTIVE

To assess the efficacy and safety of sandwich isolation surgery on the local control of progressive desmoid tumors involving neurovascular bundles.

METHODS

A total of 27 patients with progressive desmoid tumors at extremities involving neurovascular bundles who received surgery at our hospital between August 2014 and August 2018 were identified. A total of 13 patients received sandwich isolation surgery, in which R2 resection was performed in neurovasculature-involving regions, and a biomaterial patch was used to envelop involved neurovascular structures and isolate residual tumors. In non-neurovasculature-involving regions, wide resection was performed without isolation. A total of 14 patients received traditional surgery, which included tumor resection without isolation procedure.

RESULTS

In sandwich isolation group, tumor progressions and local recurrences occurred in 3 patients outside the isolated neurovasculature-involving regions. However, no progressions or recurrences occurred in any patients in the isolated neurovasculature-involving regions where R2 resection was performed. Sandwich isolation surgery group and traditional surgery group shared similar baseline clinical characteristics. The estimated 3-yr event-free survival rate was 76.9% after sandwich isolation surgery, and 32.7% after traditional surgery (P = .025). Patients who received sandwich isolation surgery were less likely to have local recurrence (hazard ratio: 0.257, P = .040). No complications were noted except intermittent mild pain in operative regions (2 cases).

CONCLUSION

Sandwich isolation surgery is effective and safe for local control of desmoid tumors involving neurovascular bundles.

Discontinuous polyostotic fibrous dysplasia with multiple systemic disorders and unique genetic mutations: A case report

BACKGROUND

Polyostotic fibrous dysplasia (PFD) is an uncommon developmental bone disease in which normal bone and marrow are replaced by pseudotumoral tissue. The etiology of PFD is unclear, but it is generally thought to be caused by sporadic, post-zygotic mutations in the GNAS gene. Herein, we report the case of a young female with bone pain and lesions consistent with PFD, unique physical findings, and gene mutations.

CASE SUMMARY

A 27-year-old female presented with unbearable bone pain in her left foot for 4 years. Multiple bone lesions were detected by radiographic examinations, and a diagnosis of PFD was made after a biopsy of her left calcaneus with symptoms including pre-axial polydactyly on her left hand and severe ophthalmological problems such as high myopia, vitreous opacity, and choroidal atrophy. Her serum cortisol level was high, consistent with Cushing syndrome. Due to consanguineous marriage of her grandparents, boosted whole exome screening was performed to identify gene mutations. The results revealed mutations in HSPG2 and RIMS1, which may be contributing factors to her unique findings.

CONCLUSION

The unique findings in this patient with PFD may be related to mutations in the HSPG2 and RIMS1 genes.

Chromosomal translocation-derived aberrant Rab22a drives metastasis of osteosarcoma

Osteosarcoma is a type of aggressive malignant bone tumour that frequently metastasizes to lungs, resulting in poor prognosis. However, the molecular mechanisms of lung metastasis of osteosarcoma remain poorly understood. Here we identify exon-intron fusion genes in osteosarcoma cell lines and tissues. These fusion genes are derived from chromosomal translocations that juxtapose the coding region for amino acids 1-38 of Rab22a (Rab22a1-38) with multiple inverted introns and untranslated regions of chromosome 20. The resulting translation products, designated Rab22a-NeoFs, acquire the ability to drive lung metastasis of osteosarcoma. The Rab22a1-38 moiety governs the function of Rab22a-NeoFs by binding to SmgGDS-607, a GTP-GDP exchange factor of RhoA. This association facilitates the release of GTP-bound RhoA from SmgGDS-607, which induces increased activity of RhoA and promotes metastasis. Disrupting the interaction between Rab22a-NeoF1 and SmgGDS-607 with a synthetic peptide prevents lung metastasis in an orthotopic model of osteosarcoma. Our findings may provide a promising strategy for a subset of osteosarcoma patients with lung metastases.

Author Correction: Chromosomal translocation-derived aberrant Rab22a drives metastasis of osteosarcoma

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A novel layer-by-layer heterogeneous cation exchange membrane for heavy metal ions removal from water

A novel layer-by-layer (LbL) cation exchange membrane was prepared for heavy metal ions removal from water via electrodialysis. LBL membranes fabricated by coating of [chitosan-co-activated carbon nanoparticles] layer on polyvinyl chloride-based heterogeneous cation exchange membrane. Betterment in adherence of layers was achieved through glutaraldehyde cross linking. FTIR, FESEM, 3D-surface images and BET analysis were used for LBL membrane characterization. Membrane surface hydrophilicity, flux, membrane potential, transport number, and their permselectivity were studied. FTIR spectra confirm LbL formation decisively. FESEM images and BET analysis demonstrated that coating of second layer on PVC membrane led to a compact structure. LbL membrane showed smoother and more hydrophilic surface compared to pristine membrane. The transport number and permselectivity increased by deposition of second layer whereas sodium flux showed up-down trend. ED experiment showed good ability in heavy metal ions removal for LBL membrane that follows (Cu²⁺> Ni²⁺> Pb²⁺) sequence. EDX analysis showed a competitive adsorption for heavy metal ions on LBL membrane as (Pb²⁺> Cu²⁺≥Ni²⁺). The effect of ultrasonic waves on regeneration of fouled membranes by heavy metals was investigated. The results showed improved performance for the regenerated membrane. Mechanical resistance also improved by utilizing of ACNs in chitosan layer.

Telangiectatic osteosarcoma: Outcome analyses and a diagnostic model for differentiation from aneurysmal bone cyst

BACKGROUND AND PURPOSE

Telangiectatic osteosarcoma (TOS), a rare variant of osteosarcoma, may be easily misdiagnosed as aneurysmal bone cyst (ABC). The aims of this study were to investigate the diagnostic and prognostic factors of TOS by reviewing our experience with TOS and to develop a diagnostic model that may distinguish TOS from ABC.

MATERIALS AND METHODS

We identified 51 cases of TOS treated at the First Affiliated Hospital of Sun Yat-Sen University from March 2001 to January 2016 and reviewed their records, imaging information and pathological studies. A diagnostic model was developed to differentiate TOS and ABC by Bayes discriminant analysis and was evaluated. The log-rank test was used to analyze the prognostic factors of TOS and to compare the outcome differences between TOS and other high-grade osteosarcoma subtypes.

RESULTS

The multi-disciplinary diagnostic method employed that combined clinical, imaging, and pathological studies enhanced the diagnostic accuracy. Age 18 years or younger and pathologic fracture were more common among the TOS patients than among the ABC patients (P = .004 and .005, respectively). The average white blood cell (WBC), platelet, lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) values of the TOS patients were higher than those of the ABC patients (P = .002, .003, .007, and .007, respectively). Our diagnostic model, including the aforementioned factors, accurately predicted 62% and 78% of the TOS patients in the training and validation sets, respectively. The 5-year estimates of event-free survival and overall survival of the TOS patients were 52.5 ± 9.4% and 54.9 ± 8.8%, respectively, which were similar to those of patients with other osteosarcoma subtypes (P = .950 and .615, respectively). Tumor volume and the LDH level were predictive prognostic factors (P = .040 and .044) but not the presence of pathologic fracture or misdiagnosis (P = .424 and .632, all respectively).

CONCLUSIONS

The multi-disciplinary diagnostic method and diagnostic model based on predictive factors, i.e., age, the presence of pathologic fracture, and platelet, LDH, ALP and WBC levels, aided the differentiation of TOS and ABC. Smaller tumors and normal LDH levels were associated with better outcomes.

Metformin reduces SATB2-mediated osteosarcoma stem cell-like phenotype and tumor growth via inhibition of N-cadherin/NF-kB signaling

OBJECTIVE

To investigate the role of SATB2 in stem cell-like properties of osteosarcoma and identify new strategies to eliminate cancer stem cells of osteosarcoma.

MATERIALS AND METHODS

Osteosarcoma cancer stem cells were derived by sarcosphere generation or chemo drug enrichment. SATB2 and pluripotency-associated gene expression in osteosarcoma CSCs were analyzed using qRT-PCR and Western blotting. The sphere formation assay, cell counting kit-8 assay and anti-chemotherapy proteins were used to measure the effects of altered SATB2, N-cadherin expression or metformin treatment in CSCs. Nude mice were injected with SATB2-deficient U2OS/MTX cells to assess the role of SATB2 in osteosarcoma growth and chemoresistance in vivo. Bioinformatics analyses were performed to identify SATB2 downstream target genes and immunochemistry to determine the correlation between SATB2 expression and patient outcome. Western blotting and luciferase reporter assays were used to examine the effects of N-cadherin and SATB2 inhibition on the NF-kB pathway.

RESULTS

SATB2 was upregulated in osteosarcoma stem cells. Knockdown of SATB2 decreased sarcosphere formation, cell proliferation and stem cell-like gene expression in vitro, meanwhile reduced tumor growth and chemoresistance in vivo. High SATB2 expression in osteosarcoma patient samples was associated with poor clinical outcome. N-cadherin was one critical downstream target gene of SATB2 that mediated the stem cell-like phenotype. Reduction of SATB2 or N-cadherin resulted in NF-kB inactivation, which led to impaired osteosarcoma sphere formation and tumor cell proliferation. Metformin treatment of osteosarcoma cells enhanced the effects of chemotherapy via suppression of N-cadherin.

CONCLUSIONS

SATB2 plays an important role in regulating osteosarcoma stem cell-like properties and tumor growth. The combination of conventional chemotherapy and metformin may be a promising therapeutic strategy for osteosarcoma patients.

LDOC1 regulates Wnt5a expression and osteosarcoma cell metastasis and is correlated with the survival of osteosarcoma patients

Osteosarcomas are common bone malignancies in children and adolescents. LDOC1 (leucine zipper, down-regulated in cancer 1), a tumor suppressor, is down-regulated in many cancers. In this study, we investigated the role of LDOC1 in tumor metastasis and its prognostic significance in osteosarcomas. We established osteosarcoma cells stably expressing LDOC1, driven by an HIV-based lentiviral system. We investigated the impact of LDOC1 on migration and invasion abilities in these cells using a transwell assay. LDOC1-associated changes in expression of metastasis-promoting genes were analyzed with a quantitative real-time polymerase chain reaction primer array. A xenograft tumor model (n = 7 mice/group) was used to assess the effect of LDOC1 on osteosarcoma metastasis in vivo. The overall survival and disease-free survival of osteosarcoma patients (n = 74) were analyzed retrospectively based on immunohistochemical analysis of LDOC1 levels in tumors and Kaplan-Meier analysis. LDOC1-expressing osteosarcoma cells displayed decreased migration and invasion in vitro. The quantitative real-time polymerase chain reaction primer array data showed that increased LDOC1 expression up-regulated many metastasis-suppressor genes. In the xenograft model, micro-computed tomography imaging data indicated that increased LDOC1 expression is associated with weaker lung metastasis ability. The Wnt5a signaling pathway promotes osteosarcoma metastasis; LDOC1 expression decreased Wnt5a levels in osteosarcoma cells. Kaplan-Meier analysis showed that higher LDOC1 expression was associated with improved osteosarcoma patient overall survival and disease free survival (p = 0.022). Our data show that LDOC1 is a tumor suppressor in osteosarcoma, and that it regulates metastasis of osteosarcoma cells. Furthermore, LDOC1 might be a valuable prognostic marker in osteosarcomas.

Oridonin induced apoptosis through Akt and MAPKs signaling pathways in human osteosarcoma cells

Previous studies have shown that oridonin, a diterpenoid isolated from Rabdosia rubescens, was able to inhibit proliferation and induce apoptosis in several cell types. But the mechanisms remain poorly understood. In this study, we investigated the apoptosis-inducing effect and mechanisms of action of oridonin in human osteosarcoma cells. Our results demonstrated that oridonin induced concentration- and time-dependent suppression of proliferation and activation of apoptosis in U2OS, MG63 and SaOS-2 osteosarcoma cell lines. Oridonin induced the release of cytochrome c accompanied by activation of caspase-9, caspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP). These events were all inhibited by z-VAD-fmk, a universal inhibitor of caspases. Oridonin treatment dephosphorylated constitutively active AKT, FOXO transcription factor, and glycogen synthase kinase 3 (GSK3). In addition, oridonin decreased the phosphorylation of ERK and increased the phosphorylation of p38 MAPK and JNK. Furthermore, oridonin treatment down-regulated the expression of the inhibitor of apoptosis protein(IAP) in osteosarcoma cells. All together, our results suggested that oridonin is able to inactivate Akt and ERK and activate p38 MAPK and JNK signalling pathways in osteosarcoma cells causing the suppression of proliferation and induction of mitochondria- and caspase-dependent apoptosis.

[Proteomics research of bufalin-induced apoptosis in osteosarcoma cell lines]

OBJECTIVE

To study the apoptosis inducing effects of bufalin on various human osteosarcoma cells and the concerning molecular mechanisms.

METHOD

MTT assay was used to detect the growth inhibition rates of osteosarcoma cells U-20S, U-20S/MTX300, SaOS-2, IOR/OS9 treated with bufalin in different concentrations and times. The apoptosis of cells was observed flow cytometry 48 h following bufalin treatment. The proteomic techniques were used to separate and compare the treated and control groups 48 h after bufalin-incubation. Then, the proteomic results were validated by western blot.

RESULT

Bufalin inhibited the growth of human osteosarcoma cells U20S, U20S/MTX300 (methotrexate resistant cells), SAOS2, IOR/OS9 in a dose- and time-dependent manner. The 72 h IC50 were (37.43 +/- 4.1), (32.24 +/- 5.3) nmol x L(-1) in U20S,U20S/MTX300 cells,respectivly. Flow cytometry showed that the apoptosis cells were increased following bufalin treatment. The protein expression profile showed 24 differentiated expression proteins. Among these proteins, the level of an anti-apoptotic protein, heat shock protein 27 (Hsp27) decreased significantly and the result was then validated by western blot. Ectopic expression of Hsp27 could reduce the bufalin-induced apoptosis remarkably in U20S and U20S/MTX300 cells.

CONCLUSION

Bufalin could inhibit the cell growth and induce apoptosis on human osteosarcoma cells. The effect of bufalin may be related to the joint intervention with multiple protein targets. Among them, downregulation of Hsp27 plays a critical role in the bufalin-induced apoptosis in human osteosarcoma cells.

The glycogen synthase kinase-3β/nuclear factor-kappa B pathway is involved in cinobufagin-induced apoptosis in cultured osteosarcoma cells

Cinobufagin, a major component of cinobufacini (huachansu), is an important cardenolidal steroid. Several studies have suggested that cinobufagin has potent anti-cancer effects. The present study examines the apoptosis-inducing activity and the underlying mechanism of action of cinobufagin in osteosarcoma (OS) cells. Our results showed that cinobufagin potently inhibited the proliferation of U2OS, MG63 and SaOS-2 cells. Significant increases in G2/M cell-cycle arrest and apoptosis in OS cells were also observed. The expression levels of several apoptotic proteins were assessed after cinobufagin treatment in U2OS cells. Among them, xIAP, cIAP-1, survivin and Bcl-2 levels decreased remarkably, while the levels of Bax and cleaved-PARP increased. Furthermore, we validated the inhibition of GSK-3β/NF-κB signaling following cinobufagin treatment. Western blots showed a decrease in nuclear p65 protein expression after exposure to different concentrations of cinobufagin, while the phosphorylation of GSK-3β was simultaneously increased. Transduction with constitutively active forms of GSK-3β could protect against the downregulation of p65 and upregulation of cleaved-PARP that are induced by cinobufagin treatment. However, combined treatment with cinobufagin and SB216367 resulted in a significant reduction in p65 and an increase in cleaved-PARP in U2OS cells. Altogether, these results show that cinobufagin is a promising agent for the treatment of OS. These studies are the first to reveal the involvement of the GSK-3β/NF-κB pathway in cinobufagin-induced apoptosis.

Enrichment of osteosarcoma stem cells by chemotherapy

Osteosarcoma is the most common primary malignant bone cancer in children and adolescents. Emerging evidence has suggested that the capability of a tumor to grow is driven by a small subset of cells within a tumor, termed cancer stem cells (CSCs). Although several methods have been explored to identify or enrich CSCs in osteosarcoma, these methods sometimes seem impractical, and chemotherapy enrichment for CSCs in osteosarcoma is rarely investigated. In the present study, we found that short exposure to chemotherapy could change the morphology of osteosarcoma cells and increase sarcosphere formation in vitro, as well as increase tumor formation in vivo. Furthermore, methotrexate (MTX)-resistant U2OS/MTX300 osteosarcoma cells were larger in size and grew much more tightly than parental U2OS cells. More importantly, U2OS/MTX300 cells possessed a higher potential to generate sarcospheres in serum-free conditions compared to parental U2OS cells. Also, U2OS/MTX300 cells exhibited the side population (SP) phenotype and expressed CSC surface markers CD117 and Stro-1. Notably, U2OS/MTX300 cells showed a substantially higher tumorigenicity in nude mice relative to U2OS cells. Therefore, we conclude that chemotherapy enrichment is a feasible and practical way to enrich osteosarcoma stem cells.

Analysis of the efficacy and prognosis of limb-salvage surgery for osteosarcoma around the knee

AIM

Limb-salvage surgery has become the standard of care for extremity osteosarcoma. In this study, we investigated the survival and functional outcomes of patients with osteosarcoma around the knee who were treated with limb-salvage surgery.

METHODS

We retrospectively reviewed the clinical data for 120 patients with osteosarcoma around the knee who were treated with limb-salvage surgery between 1998 and 2008. The sample included 75 males and 45 females. The mean age of the patients was 18.9 years. Osteosarcoma was diagnosed in the distal femur in 78 patients and in the proximal tibia in 42 patients. Statistical analyses were conducted to process and record the patient data and analyse the surgery's efficacy, prognosis and survival rates.

RESULTS

All patients were followed for 6-144 months (mean of 56.8 months). The overall 5-year survival rate was 61.8%. Lung metastasis developed in 31 patients. Local recurrence developed in 9 patients. The average Musculoskeletal Tumor Society Score (MSTS) was 25.5 points on a 30-point scale. Sixteen patients underwent prosthesis revision and twelve patients underwent amputation. The overall survivorship of the prosthesis based on Kaplan-Meier estimates was 77% at five years and 71% at ten years. There was a higher incidence of extensor lag for the patients with osteosarcoma in the proximal tibia than for those with osteosarcoma in the distal femur (P < 0.01).

CONCLUSIONS

Treating osteosarcoma around the knee with limb-salvage surgery can preserve most of the knee's functionality. Attention must be paid to prevent the relatively high incidence of postoperative complications.

Glycogen synthase kinase-3β, NF-κB signaling, and tumorigenesis of human osteosarcoma

Background

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, may function as a tumor suppressor or an oncogene, depending on the tumor type. We sought to determine the biological function of GSK-3β in osteosarcoma, a rare pediatric cancer for which the identification of new therapeutic targets is urgent.

Methods

We used cell viability assays, colony formation assays, and apoptosis assays to analyze the effects of altered GSK-3β expression in U2OS, MG63, SAOS2, U2OS/MTX300, and ZOS osteosarcoma cell lines. Nude mice (n = 5–8 mice per group) were injected with U2OS/MTX300, and ZOS cells to assess the role of GSK-3β in osteosarcoma growth in vivo and to evaluate the effects of inhibitors and/or anticancer drugs on tumor growth. We used an antibody array, polymerase chain reaction, western blotting, and a luciferase reporter assay to establish the effect of GSK-3β inhibition on the nuclear factor-κB (NF-κB) pathway. Immunochemistry was performed on primary tumor specimens from osteosarcoma patients (n = 74) to determine the relationship of GSK-3β activity with overall survival.

Results

Osteosarcoma cells with low levels of inactive p-Ser9-GSK-3β formed colonies in vitro and tumors in vivo more readily than cells with higher levels and cells in which GSK-3β had been silenced formed fewer colonies and smaller tumors than parental cells. Silencing or pharmacological inhibition of GSK-3β resulted in apoptosis of osteosarcoma cells. Inhibition of GSK-3β resulted in inhibition of the NF-κB pathway and reduction of NF-κB-mediated transcription. Combination treatments with GSK-3β inhibitors, NF-κB inhibitors, and chemotherapy drugs increased the effectiveness of chemotherapy drugs in vitro and in vivo. Patients whose osteosarcoma specimens had hyperactive GSK-3β, and nuclear NF-κB had a shorter median overall survival time (49.2 months) compared with patients whose tumors had inactive GSK-3β and NF-κB (109.2 months).

Conclusion

GSK-3β activity may promote osteosarcoma tumor growth, and therapeutic targeting of the GSK-3β and/or NF-κB pathways may be an effective way to enhance the therapeutic activity of anticancer drugs against osteosarcoma.

Increased expression of serum gelsolin in patients with osteosarcoma

BACKGROUND

Identification of potential serum biomarkers of osteosarcoma to aid in its early diagnosis and in the discovery of possible therapeutic targets is an area of increasing interest.

METHODS

Two-dimensional difference-in-gel electrophoresis was used to assess multiple serum samples in patients with osteosarcoma. In addition, differential expression of protein biomarkers was characterized in osteosarcoma serum by using matrix-assisted desorption/ionization time-of-flight mass spectrometry coupled with database interrogation. Serum samples from four individuals with osteosarcoma and four age- and sex-matched healthy control subjects were compared.

RESULTS

Fifty-eight significant protein spot features in the osteosarcoma sera were found. These spot features were excised, digested with trypsin, and analyzed with mass spectrometry. Gelsolin was down-regulated only in osteosarcoma. Furthermore, Western blotting and enzyme linked immunosorbent assay (ELISA) confirmed decreased levels of gelsolin in the osteosarcoma serum samples.

CONCLUSIONS

These results indicated that gelsolin might have great potential as a biomarker of osteosarcoma and as a potential target for gene therapy.

Salinomycin inhibits osteosarcoma by targeting its tumor stem cells

Osteosarcoma is the most common primary bone tumor in children and adolescents and is typically associated with a poor prognosis. Tumor stem cells (TSCs) are presumed to drive tumor initiation and tumor relapse or metastasis. Hence, the poor prognosis of osteosarcoma likely results from a failure to target the osteosarcoma stem cells. Here, we have utilized three different methods to enrich TSCs in osteosarcoma and further evaluated whether salinomycin could selectively target TSCs in osteosarcoma. Our results indicated that sarcosphere selection, chemotherapy selection and stem cell marker OCT4 or SOX2 over-expression are all effective in the enrichment of TSCs from osteosarcoma cell lines. Further investigation found that salinomycin inhibited osteosarcoma by selectively targeting its stem cells both in vitro and in vivo without severe side effects, and the Wnt/β-catenin signaling pathway may be involved in this inhibition of salinomycin. Taken together, we have identified that salinomycin is an effective inhibitor of osteosarcoma stem cells, supporting the use of salinomycin for elimination of osteosarcoma stem cells and implying a need for further clinical evaluation.

Eosinophilic granuloma of bilateral humerus with unusual diagnostic process

A 15-year-old boy presented with a right shoulder pain and the inability to use his right upper limb after carrying a heavy object. Physical examination and local imaging revealed a benign tumor or tumor-like lesion in the upper ends of both humeri and a pathologic fracture in the right humerus. An initial biopsy was reported as fibroblastic osteosarcoma. But the CT-guided biopsy was diagnosed as eosinophilic granuloma (EG). Bone curretage and grafting confirmed diagnosis of EG. This case illustrates the importance of combining a clinical impression with imaging and pathology in bone and soft tissue tumors.

[Detection of serum biomakers of osteosarcoma by proteomic profiling]

OBJECTIVE

To detect differentially expressed proteins in serum of patient with osteosarcoma.

METHODS

8 serum protein samples were recruited (4 cases of osteosarcoma and 4 cases of normal adults), cross-labeled with variant CyDye, followed by two-dimensional differential in-gel electrophoresis (2-D DIGE), image analysis, and identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS).

RESULTS

24 protein spot-features were significantly increased, and 34 were significantly decreased in the serum from patients with osteosarcoma relative to the controls. The mass spectrometry analysis revealed 18 unique proteins that were increased, and 25 unique proteins decreased in the serum of patients with osteosarcoma. Gelsolin was down-regulated in osteosarcoma, and Western blotting also confirmed a decreased level of gelsolin in the serum of patients with osteosarcoma.

CONCLUSION

Our results indicate that gelsolin may have great potential as a biomarker of osteosarcoma and as a potential target for therapy. These preliminary data suggest that incorporation of more samples and new datasets will permit the identification of serum biomarkers for osteosarcoma.

[Reconstruction of the hemipelvis with saddle prosthesis after excision of malignant tumors around the pelvis and acetabulum: a report of 12 cases]

BACKGROUND & OBJECTIVE

Malignant tumors around the pelvis and acetabulum locate deeply with complex anatomic structure, meanwhile, the resection area involves the weight-loading alignment. Therefore, tumor resection plus acetabular joint reconstruction is a complicated operation. This study was to summarize our experience of tumor resection plus prosthesis reconstruction of the acetabular joint for this disease.

METHODS

Clinical data of 12 patients with malignant tumors around the pelvis and acetabulum, treated with tumor resection plus prosthesis reconstruction of the acetabular joint from 1995 to 2006, were reviewed. The characteristics of the operating for this disease were analyzed in terms of preoperative preparation, operating strategy, prosthesis design, operating procedure, acetabular reconstruction, and postoperative rehabilitation.

RESULTS

The patients were followed for 8-86 months, with a median of 46 months. Of the 4 patients with tumor relapse, 2 osteosarcoma patients died of lung metastasis at 15 months and 22 months after operation; 1 chondrosarcoma patient relapsed locally at 26 months after operation and died at 38 months after operation; 1 giant cell tumor patient relapsed locally at 13 months after operation and was treated by clearance of focal lesion, and survived tumor-freely till the end of follow-up. The other 9 patients still survived tumor-freely till the end of follow-up. The 1-year survival rate was 75.0%; the 3-and 5-year survival rates were 33.3%; the 7-year survival rate was 25.0%. According to Harris scoring criteria after total hip replacement, 3 patients scored 60-69, 5 scored 70-79, and 4 scored 80-90 in limb function.

CONCLUSIONS

Pelvic tumor resection and prosthesis reconstruction of the acetabular joint has the characteristics of difficulty and high-risk. For bone tumors with relatively low malignancy, this surgical treatment is an ideal option.

Comparative proteomic analysis of human osteosarcoma and SV40-immortalized normal osteoblastic cell lines

AIM

Comparative proteomics provide a powerful approach in screening for alterations in protein levels and post-translational modifications that are associated with tumors. In the present study, we aimed to identify candidate biomarkers to distinguish osteosarcoma (OS) cells from normal osteoblastic cells.

METHODS

We employed 3 OS cell lines (U2OS, IOR/OS9, and SaOS-2), and used the SV40-immortalized normal osteoblastic cell line (hFOB1.19) as the control. The differential protein levels in OS and osteoblastic cells were identified using 2-D gel electrophoresis followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry analyses. Two proteins of interest, the levels of which were significantly increased in OS cells, were further characterized by Western blot analyses.

RESULTS

Twenty-six proteins were identified, the expression level of which was either significantly increased or decreased in the OS cells as compared to the control cells. The expression level of the activator of 90 kDa shock protein ATPase homolog 1 (AHA1), was enhanced 12.4-, 24.1-, and 23.8-fold in SaOS-2, IOR/OS9, and U2OS cells, respectively, and the level of the stomatin-like protein 2 (SLP-2) was increased by 10.4- and 7.8-fold in IOR/OS9 and U2OS cells, respectively, as compared to normal osteoblastic cells. Those observations were confirmed by Western blot analyses.

CONCLUSION

A differential proteomic analysis was successfully used to identify AHA1 and SLP-2 that were significantly overproduced in OS cells as compared to normal osteoblastic cells, suggesting that those proteins among others may be effective biomarker candidates for the identification of OS cells.

Bufalin induces apoptosis in human osteosarcoma U-2OS and U-2OS methotrexate300-resistant cell lines

AIM

To investigate the antiproliferative activity and apoptosis-inducing effects of bufalin on human osteosarcoma cell lines.

METHODS

U-2OS and U-2OS methotrexate (MTX) 300-resistant cell lines were treated with bufalin. Cell viability was assessed using the MTT assay. Cell-cycle status, apoptosis-inducing effects, and the expression of apoptosis-related proteins were evaluated by flow cytometry, fluorescent staining, DNA fragmentation assays, and Western blotting. The effect of bufalin on dihydrofolate reductase (DHFR) expression was studied by RTPCR and Western blotting.

RESULTS

Bufalin inhibited cell growth in both U-2OS and U-2OS MTX300 cells. The induction of G2/M cell-cycle arrest was also seen in the cells treated with bufalin. The induction of apoptosis by bufalin was confirmed by increased expression of the tumor suppressor protein p53 and the increased ratio of the Bax/Bcl-2 proteins. Bufalin induced apoptosis to the same extent in both cell lines without regard to DHFR levels in the cells.

CONCLUSION

Bufalin inhibited the growth of and induced apoptosis in both MTX-sensitive and MTX-resistant human osteosarcoma U-2OS cells. The apoptosis-inducing effect of bufalin was not influenced by the presence of high levels of the DHFR protein.

Grifolin induces apoptosis via inhibition of PI3K/AKT signalling pathway in human osteosarcoma cells

Grifolin, a natural biologically active substance isolated from the edible bodies of the mushroom Albatrellus confluens, has been shown to inhibit proliferation and induce apoptosis in several cancer cell lines. But the mechanisms remain poorly understood. In this study, we investigated the apoptosis-inducing effects and the mechanisms of grifolin on human osteosarcoma cells. Our results demonstrated that grifolin induced concentration- and time-dependent suppression of proliferation and induction of apoptosis in U2OS and MG63 osteosarcoma cell lines. Grifolin induced the release of cytochrome c accompanied by activation of caspase-9, caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP). In addition, z-VAD-fmk, a universal inhibitor of caspases, prevented caspase-3 activation and PARP cleavage and inhibted grifolin-induced cell growth inhibition. Furthermore, grifolin treatment resulted in a reduction in level of phosphorylated AKT, FOXO transcription factor, and glycogen synthase kinase 3 (GSK3). Knockdown of GSK3 with siRNA inhibited the apoptotic effects of grifolin. On the other hand, grifolin treatment down-regulated the expression of the inhibitor of apoptosis protein(IAP) in both osteosarcoma cells. Taken together, our results suggested that grifolin is able to suppress the phosphorylation of Akt and its substrates FOXO transcription factor and GSK3 in osteosarcoma cells causing the suppression of proliferation and induction of mitochondria- and caspase-dependent apoptosis.