The adolescent and young adult with cancer: state of the art -- bone tumors

Deubiquitinase USP10 promotes osteosarcoma autophagy and progression through regulating GSK3β-ULK1 axis

BACKGROUND

Deubiquitinating enzymes (DUBs) are pivotal in maintaining cell homeostasis by regulating substrate protein ubiquitination in both healthy and cancer cells. Ubiquitin-specific protease 10 (USP10) belongs to the DUB family. In this study, we investigated the clinical and pathological significance of USP10 and Unc-51-like autophagy activating kinase 1 (ULK1) in osteosarcoma (OS), as well as the mechanism of USP10 action in ULK1-mediated autophagy and disease progression.

RESULTS

The analysis of OS and adjacent normal tissues demonstrated that USP10 and ULK1 were significantly overexpressed in OS, and a positive association between their expression and malignant properties was observed. USP10 knockdown in OS cells reduced ULK1 mRNA and protein expression, whereas USP10 overexpression increased ULK1 mRNA and protein expression. In vitro experiments showed that USP10 induced autophagy, cell proliferation, and invasion by enhancing ULK1 expression in OS cell lines. Furthermore, we found that the regulation of ULK1-mediated autophagy, cell proliferation, and invasion in OS by USP10 was dependent on glycogen synthase kinase 3β (GSK3β) activity. Mechanistically, USP10 promoted ULK1 transcription by interacting with and stabilising GSK3β through deubiquitination, which, in turn, increased the activity of the ULK1 promoter, thereby accelerating OS progression. Using a xenograft mouse model, we showed that Spautin-1, a small-molecule inhibitor targeting USP10, significantly reduced OS development, with its anti-tumour activity significantly enhanced when combined with the chemotherapeutic agent cisplatin.

CONCLUSION

Collectively, we demonstrated that the USP10-GSK3β-ULK1 axis promoted autophagy, cell proliferation, and invasion in OS. The findings imply that targeting USP10 may offer a promising therapeutic avenue for treating OS.

The survival disparity between children and adolescents and young adults (AYAs) with Ewing sarcoma in the Netherlands did not change since the 1990s despite improved survival: A population-based study

BACKGROUND

Adolescents and young adults (AYAs) with Ewing sarcoma have a worse prognosis than children. Population-based survival evaluations stratifying findings by important clinical factors are, however, limited. This Dutch population study comprehensively compared survival of children and AYAs with Ewing sarcoma over three decades considering diagnostic period, tissue of origin, tumor site, and disease stage.

METHODS

Data on all children (0-17 years, N = 463) and AYAs (18-39 years, N = 379) diagnosed with Ewing sarcoma in the Netherlands between 1990-2018 were collected from the Netherlands Cancer Registry with follow-up until February 2023. Five-year relative survival was calculated using the cohort method. Multivariable analyses were conducted through Poisson regression.

RESULTS

Children with Ewing sarcoma had a significantly higher 5-year relative survival than AYAs (65 % vs. 44 %). An increasing trend in survival was noted reaching 70 % in children and 53 % in AYAs in 2010-2018. Results were similar for Ewing bone sarcoma and extraosseous Ewing sarcoma. AYAs had a poorer prognosis than children for most tumor sites and regardless of disease stage. Survival probabilities were 60 % vs. 78 % for localized disease and 20 % vs. 33 % for metastatic disease. Multivariable-regression analysis, adjusted for follow-up time, diagnostic period, sex, disease stage, and tumor site, confirmed increased excess mortality among AYAs compared with children (excess HR: 1.7, 95 % CI: 1.3-2.1).

CONCLUSIONS

Despite survival improvements since the 1990s, AYAs with Ewing sarcoma in the Netherlands continue to fare considerably worse than children. This survival disparity was present irrespective of tissue of origin, tumor site, and disease stage.

Cellular senescence-driven transcriptional reprogramming of the MAFB/NOTCH3 axis activates the PI3K/AKT pathway and promotes osteosarcoma progression

Osteosarcoma is the most common primary malignancy of bones and primarily occurs in adolescents and young adults. However, a second smaller peak of osteosarcoma incidence was reported in the elderly aged more than 60. Elderly patients with osteosarcoma exhibit different characteristics compared to young patients, which usually results in a poor prognosis. The mechanism underlying osteosarcoma development in elderly patients is intriguing and of significant value in clinical applications. Senescent cells can accelerate tumor progression by metabolic reprogramming. Recent research has shown that methylmalonic acid (MMA) was significantly up-regulated in the serum of older individuals and played a central role in the development of aggressive characteristics. We found that the significant accumulation of MMA in elderly patients imparted proliferative potential to osteosarcoma cells. The expression of MAFB was excessively up-regulated in osteosarcoma specimens and was further enhanced in response to MMA accumulation as the patient aged. Specifically, we first confirmed a novel molecular mechanism between cellular senescence and cancer, in which the MMA-driven transcriptional reprogramming of the MAFB-NOTCH3 axis accelerated osteosarcoma progression via the activation of PI3K-AKT pathways. Moreover, the down-regulation of the MAFB-NOTCH3 axis increased the sensitivity and effect of AKT inhibitors in osteosarcoma through significant inhibition of AKT phosphorylation. In conclusion, we confirmed that MAFB is a novel age-dependent biomarker for osteosarcoma, and targeting the MAFB-NOTCH3 axis in combination with AKT inhibition can serve as a novel therapeutic strategy for elderly patients with osteosarcoma in experimental and clinical trials.

A multifunctional nano-hydroxyapatite/MXene scaffold for the photothermal/dynamic treatment of bone tumours and simultaneous tissue regeneration

After resection of bone tumour, the risk of cancer recurrence and numerous bone defects continues to threaten the health of patients. To overcome the challenge, we developed a novel multifunctional scaffold material consisting mainly of nano-hydroxyapatite particles (n-HA), MXene nanosheets and g-C3N4 to prevent tumour recurrence and promote bone formation. N-HA has the potential to restrict the growth of osteosarcoma cells, and the combination of MXene and g-C3N4 enables the scaffolds to produce photodynamic and photothermal effects simultaneously under near infrared (NIR) irradiation. Surprisingly, n-HA can further enhance the synergistic anti-tumour function of photodynamic and photothermal, and the scaffolds can eradicate osteosarcoma cells in only 10 min at a mild temperature of 45 ℃. Moreover, the scaffold exhibit exceptional cytocompatibility and possesses the capacity to induce osteogenic differentiation of bone marrow mesenchymal stem cells. Therefore, this multifunctional scaffold can not only inhibits the proliferation of bone tumour cells and rapidly eradicate bone tumour through NIR irradiation, but also enhances osteogenic activity. This promising measure can be used to treat tissue damage after bone tumour resection.

Diagnostic Value of Dual-Energy CT Virtual Non-Calcium and Rho/Z Images for Bone Marrow Infiltration in Primary Malignant Bone Tumors

RATIONALE AND OBJECTIVES

We investigated the diagnostic performance of dual-energy CT (DECT) virtual non-calcium (VNCa) and Rho/Z images for bone marrow infiltration of primary malignant bone tumors (PMBTs).

MATERIALS AND METHODS

We retrospectively analyzed 65 patients with PMBT who underwent DECT and MRI within 2 weeks. DECT was used to evaluate the presence and extent of marrow involvement surrounding PMBTs using the SCT, VNCa, and Rho/Z images. MRI was used as the reference standard for measurements. CT values of normal and involved bone marrow areas were measured on VNCa images, and Zeff values were measured on Rho/Z images. The statistical methods used were the 2*C chi-square test, ANOVA test, paired samples t test, and diagnostic performance of the different variables were evaluated using receiver operating characteristic curves.

RESULTS

VNCa and Rho/Z images showed higher accuracy (91%, 92% vs. 67%) and sensitivity (90%, 92% vs. 69%) than SCT images for diagnosing bone marrow infiltration in patients with PMBT. The maximum longitudinal diameter of tumor involvement measurements was statistically different between VNCa and SCT, Rho/Z and SCT, MRI, and SCT (all p < 0.05, p = 0.047, p = 0.049, and p = 0.023, respectively). The maximum transverse diameter was statistically significant between SCT and MRI, VNCa and MRI, Rho/Z and MRI (all p < 0.05, and p = 0.015, and p = 0.044, and p = 0.047, respectively). The HU or Zeff values based on the area of interest of VNCa and Rho/Z images differed significantly between the normal and infiltrated bone marrow area (p < 0.001). Receiver operating characteristic curve analysis revealed area under the curves of 0.995 and 0.988, respectively, with cut-off values of -31.57 HU and 7.8, and the sensitivity of both was 96.9%.

CONCLUSION

DECT-VNCa and Rho/Z images have good diagnostic value when evaluating bone marrow infiltration in PMBTs.

Injectable thermosensitive black phosphorus nanosheet- and doxorubicin-loaded hydrogel for synergistic bone tumor photothermal-chemotherapy and osteogenesis enhancement

Removing residual tumor cells around bone tissue and promoting bone defect repair pose significant challenges after osteosarcoma resection. Herein, we designed an injectable multifunctional hydrogel therapeutic platform for synergistic photothermal chemotherapy of tumors and promoting osteogenesis. In this study, the black phosphorus nanosheets (BPNS) and doxorubicin (DOX) were encapsulated in an injectable chitosan-based hydrogel (BP/DOX/CS). The BP/DOX/CS hydrogel exhibited excellent photothermal effects under NIR irradiation due to incorporating BPNS. The prepared hydrogel has good drug-loading capacity and can continuously release DOX. In addition, K7M2-WT tumor cells are effectively eliminated under the combined effect of chemotherapy and photothermal stimulation. Furthermore, the BP/DOX/CS hydrogel has good biocompatibility and promotes osteogenic differentiation of MC3T3-E1 cells by releasing phosphate. In vivo results also confirmed that the BP/DOX/CS hydrogel can be injected at the tumor site to eliminate the tumor efficiently without systemic toxicity. This easily prepared multifunctional hydrogel with a synergistic photothermal-chemotherapy effect has excellent potential for clinically treating bone-related tumors.

Establishing and Validating an Aging-Related Prognostic Signature in Osteosarcoma

Aging is an inevitable process that biological changes accumulate with time and results in increased susceptibility to different tumors. But currently, aging-related genes (ARGs) in osteosarcoma were not clear. We investigated the potential prognostic role of ARGs and established an ARG-based prognostic signature for osteosarcoma. The transcriptome data and corresponding clinicopathological information of patients with osteosarcoma were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Molecular subtypes were generated based on prognosis-related ARGs obtained from univariate Cox analysis. With ARGs, a risk signature was built by univariate, least absolute shrinkage and selection operator (LASSO), and multivariate Cox regression analyses. Differences in clinicopathological features, immune infiltration, immune checkpoints, responsiveness to immunotherapy and chemotherapy, and biological pathways were assessed according to molecular subtypes and the risk signature. Based on risk signature and clinicopathological variables, a nomogram was established and validated. Three molecular subtypes with distinct clinical outcomes were classified based on 36 prognostic ARGs for osteosarcoma. A nine-ARG-based signature in the TCGA cohort, including BMP8A, CORT, SLC17A9, VEGFA, GAL, SSX1, RASGRP2, SDC3, and EVI2B, has been created and developed and could well perform patient stratification into the high- and low-risk groups. There were significant differences in clinicopathological features, immune checkpoints and infiltration, responsiveness to immunotherapy and chemotherapy, cancer stem cell, and biological pathways among the molecular subtypes. The risk signature and metastatic status were identified as independent prognostic factors for osteosarcoma. A nomogram combining ARG-based risk signature and metastatic status was established, showing great prediction accuracy and clinical benefit for osteosarcoma OS. We characterized three ARG-based molecular subtypes with distinct characteristics and built an ARG-based risk signature for osteosarcoma prognosis, which could facilitate prognosis prediction and making personalized treatment in osteosarcoma.

A deep belief network-based clinical decision system for patients with osteosarcoma

Osteosarcoma was the most frequent type of malignant primary bone tumor with a poor survival rate mainly occurring in children and adolescents. For precision treatment, an accurate individualized prognosis for Osteosarcoma patients is highly desired. In recent years, many machine learning-based approaches have been used to predict distant metastasis and overall survival based on available individual information. In this study, we compared the performance of the deep belief networks (DBN) algorithm with six other machine learning algorithms, including Random Forest, XGBoost, Decision Tree, Gradient Boosting Machine, Logistic Regression, and Naive Bayes Classifier, to predict lung metastasis for Osteosarcoma patients. Therefore the DBN-based lung metastasis prediction model was integrated as a parameter into the Cox proportional hazards model to predict the overall survival of Osteosarcoma patients. The accuracy, precision, recall, and F1 score of the DBN algorithm were 0.917/0.888, 0.896/0.643, 0.956/0.900, and 0.925/0.750 in the training/validation sets, respectively, which were better than the other six machine-learning algorithms. For the performance of the DBN survival Cox model, the areas under the curve (AUCs) for the 1-, 3- and 5-year survival in the training set were 0.851, 0.806 and 0.793, respectively, indicating good discrimination, and the calibration curves showed good agreement between the prediction and actual observations. The DBN survival Cox model also demonstrated promising performance in the validation set. In addition, a nomogram integrating the DBN output was designed as a tool to aid clinical decision-making.

Integrated DNA Copy Number and Expression Profiling Identifies IGF1R as a Prognostic Biomarker in Pediatric Osteosarcoma

Osteosarcoma is a primary malignant bone tumor arising from bone-forming mesenchymal cells in children and adolescents. Despite efforts to understand the biology of the disease and identify novel therapeutics, the survival of osteosarcoma patients remains dismal. We have concurrently profiled the copy number and gene expression of 226 osteosarcoma samples as part of the Strategic Partnering to Evaluate Cancer Signatures (SPECS) initiative. Our results demonstrate the heterogeneous landscape of osteosarcoma in younger populations by showing the presence of genome-wide copy number abnormalities occurring both recurrently among samples and in a high frequency. Insulin growth factor receptor 1 (IGF1R) is a receptor tyrosine kinase which binds IGF1 and IGF2 to activate downstream pathways involved in cell apoptosis and proliferation. We identify prevalent amplification of IGF1R corresponding with increased gene expression in patients with poor survival outcomes. Our results substantiate previously tenuously associated copy number abnormalities identified in smaller datasets (13q34+, 20p13+, 4q35-, 20q13.33-), and indicate the significance of high fibroblast growth factor receptor 2 (FGFR2) expression in distinguishing patients with poor prognosis. FGFR2 is involved in cellular proliferation processes such as division, growth and angiogenesis. In summary, our findings demonstrate the prognostic significance of several genes associated with osteosarcoma pathogenesis.

Multifunctional mesoporous silica nanoparticles for pH-response and photothermy enhanced osteosarcoma therapy

The recurrence and bone defect of malignant osteosarcoma postsurgical treatment have gained remarkable attention. Therefore, the development of multifunctional treatment platform is urgently desirable to achieve efficient tumor treatment and bone regeneration. In this paper, a multifunctional nanomaterial using mesoporous silica (MSN) as platform modified with quercetin (Qr), collagen (Col) and dopamine (PDA) was developed. Our findings demonstrated that the nanoparticles designed in this work had excellent photothermal properties and pH responsiveness. In addition, the nanoparticles had outstanding anti-tumor ability and could killed Saos-2 cells within 10 min under 808 nm laser irradiation owing to the synergistic effect of hyperthermia and Qr. Besides, the modification of PDA and Col endows the nanoparticles with excellent osteogenic activity.

Tspan9 Induces EMT and Promotes Osteosarcoma Metastasis via Activating FAK-Ras-ERK1/2 Pathway

Object

At present, there are few effective treatment options available to patients suffering from osteosarcoma (OS). Clarifying the signaling pathways that govern OS oncogenesis may highlight novel approaches to treating this deadly form of cancer. Recent experimental evidence suggests that the transmembrane protein tetraspanin-9 (Tspan9) plays a role in tumor development. This study was thus formulated to assess the molecular role of Tspan9 as a regulator of OS cell metastasis.

Methods

Gene expression in OS cell lines was evaluated via qRT-PCR, while CCK-8, colony formation, Transwell, and wound healing assays were used to explore the in vitro proliferative, invasive, and migratory activities of OS cells. The relationship between Tspan9 and in vivo OS cell metastasis was assessed by injecting these cells into the tail vein of nude mice. Interactions between the Tspan9 and integrin β1 proteins were explored through mass spectrometric and co-immunoprecipitation, and Western blotting to assess the functional mechanisms whereby Tspan9 shapes OS pathogenesis.

Results

Both primary OS tumors and OS cell lines commonly exhibited Tspan9 upregulation, and the knockdown of this tetraspanin suppressed the migration, invasion, and epithelial-mesenchymal transition (EMT) activity in OS cells, whereas Tspan9 overexpression resulted in opposite phenotypes. Tumor lung metastasis were significantly impaired in mice implanted with HOS cells in which Tspan9 was downregulated as compared to mice implanted with control HOS cells. Tspan9 was also found to interact with β1 integrin and to contribute to OS metastasis via the amplification of integrin-mediated downstream FAK/Ras/ERK1/2 signaling pathway.

Conclusion

These data suggest that Tspan9 can serve as a promising therapeutic target in OS.

A bone implant with NIR-responsiveness for eliminating osteosarcoma cells and promoting osteogenic differentiation of BMSCs

Incomplete removal of tumor cells and insufficient osseointegration are the main causes of bone tumor recurrence and implantation failure. In the present study, a multifunctional titanium-based bioactive implant for near-infrared-triggered synergy therapy to overcome these hurdles is engineered, composed of titanium dioxide (TiO₂) nanoparticles doped with fluorine (F)/dopamine (PDA)/collagen. The TiO₂ nanoparticles designed in this work can simultaneously exhibit excellent near-infrared-activated photothermal and photocatalytic properties. Besides, the layer designed in this work show excellent anti-tumor activity under irradiation with 808 nm light due to the synergetic effect of hyperthermia and reactive oxygen species (ROS), and Saos-2 cells can be eradicated within 10 min. Moreover, modification of PDA and collagen endue the Ti alloy excellent osteogenic activity.

Targeting the IGF/PI3K/mTOR Pathway and AXL/YAP1/TAZ pathways in Primary Bone Cancer

Primary bone cancers (PBC) belong to the family of mesenchymal tumors classified based on their cellular origin, extracellular matrix, genetic regulation, and epigenetic modification. The three major PBC types, Ewing sarcoma, osteosarcoma, and chondrosarcoma, are frequently aggressive tumors, highly metastatic, and typically occur in children and young adults. Despite their distinct origins and pathogenesis, these sarcoma subtypes rely upon common signaling pathways to promote tumor progression, metastasis, and survival. The IGF/PI3K/mTOR and AXL/YAP/TAZ pathways, in particular, have gained significant attention recently given their ties to oncogenesis, cell fate and differentiation, metastasis, and drug resistance. Naturally, these pathways – and their protein constituents – have caught the eye of the pharmaceutical industry, and a wide array of small molecule inhibitors and antibody drug-conjugates have emerged. Here, we review how the IGF/PI3K/mTOR and AXL/YAP/TAZ pathways promote PBC and highlight the drug candidates under clinical trial investigation.

The prominent role of miR-942 in carcinogenesis of tumors

As a family of short noncoding RNAs, MicroRNAs have been identified as possible biomarkers for cancer discovery and assist in therapy control due to their epigenetic involvement in gene expression and other cellular biological processes. In the present review, the evidence for reaching the clinical effect and the molecular mechanism of miR-942 in various kinds of cancer is amassed. Dysregulation of miR-942 amounts in different kinds of malignancies, as bladder cancer, esophageal squamous cell carcinoma, breast cancer, cervical cancer, gastric cancer, colorectal cancer, Kaposi's sarcoma, melanoma, Hepatocellular carcinoma, nonsmall-cell lung cancer, oral squamous cell carcinoma, osteosarcoma, ovarian cancer, pancreatic ductal adenocarcinoma, renal cell carcinoma, and prostate cancer has stated a considerable increase or decrease in its level indicating its function as oncogene or tumor suppressor. MiR-942 is included in cell proliferation, migration, and invasion through cell cycle pathways, including pathways of transforming growth factor-beta signaling pathways, Wnt pathway, JAK/STAT pathway, PI3K/AKT pathway, apoptosis pathway, hippo signaling pathway, lectin pathway, interferon-gamma signaling, signaling by G-protein coupled receptor, developmental genes, nuclear factor-kappa B pathway, Mesodermal commitment pathway, and T-cell receptor signaling in cancer. An important biomarker, MiR-942 is a potential candidate for prediction in several cancers. The present investigation introduced miR-942 as a prognostic marker for early discovery of tumor progression, metastasis, and development.

Progress of Phototherapy Applications in the Treatment of Bone Cancer

Bone cancer including primary bone cancer and metastatic bone cancer, remains a challenge claiming millions of lives and affecting the life quality of survivors. Conventional treatments of bone cancer include wide surgical resection, radiotherapy, and chemotherapy. However, some bone cancer cells may remain or recur in the local area after resection, some are highly resistant to chemotherapy, and some are insensitive to radiotherapy. Phototherapy (PT) including photodynamic therapy (PDT) and photothermal therapy (PTT), is a clinically approved, minimally invasive, and highly selective treatment, and has been widely reported for cancer therapy. Under the irradiation of light of a specific wavelength, the photosensitizer (PS) in PDT can cause the increase of intracellular ROS and the photothermal agent (PTA) in PTT can induce photothermal conversion, leading to the tumoricidal effects. In this review, the progress of PT applications in the treatment of bone cancer has been outlined and summarized, and some envisioned challenges and future perspectives have been mentioned. This review provides the current state of the art regarding PDT and PTT in bone cancer and inspiration for future studies on PT.

Knockdown of lncRNA C5orf66-AS1 inhibits osteosarcoma cell proliferation and invasion via miR-149-5p upregulation

Osteosarcoma (OS) is the most common primary malignant bone tumor in the pediatric age group. Despite the various potential treatments for OS, the cure rate of patients with OS remains very low. An increasing number of long non-coding RNAs (lncRNAs) have been identified as key regulators of the progression of malignant human tumors. However, the biological functions of the lncRNA C5orf66-antisense 1 (C5orf66-AS1) in OS are yet to be fully elucidated. The present study aimed to investigate the functions and underlying mechanisms of C5orf66-AS1 in OS tissues and cell lines. Expression levels of C5orf66-AS1 and microRNA (miRNA/miR)-149-5p in tissues from patients with OS and OS cells lines were evaluated using reverse transcription quantitative (RT-q)PCR. The miRNA target interaction between C5orf66-AS1 and miR-149-5p was predicted and verified using StarBase and dual-luciferase reporter assays. Cell viability, migration, invasion and apoptosis were analyzed using Cell Counting Kit-8, Transwell assays and flow cytometry, respectively. In addition, the expression levels of migration- and apoptosis-associated proteins [matrix metalloproteinase-9 (MMP-9), Bcl-2 and Bax] were determined using western blotting and RT-qPCR. The results demonstrated that C5orf66-AS1 was significantly upregulated and miR-149-5p was significantly downregulated in OS tissues and cells (MG63 and U2OS). Bioinformatics analysis further confirmed that miR-149-5p could directly bind to C5orf66-AS1. Furthermore, it was revealed that C5orf66-AS1 negatively regulated the expression of miR-149-5p in OS cells, as confirmed by the inhibition of C5orf66-AS1 expression and miR-149-5p upregulation in cells transfected with small interfering (si RNA targeting C5orf66-AS1. In addition, C5orf66-AS1 silencing significantly inhibited the proliferation, invasion and migration of U2OS cells, and stimulated cell apoptosis. These findings were reversed using miR-149-5p inhibitor. Increased Bax expression and decreased Bcl-2 and MMP-9 expression were also observed in C5orf66-AS1-siRNA transfected U2OS cells, compared with the control group. In summary, the results from the present study indicated that C5orf66-AS1 knockdown inhibits OS cell proliferation and invasion via the upregulation of miR-149-5p. This findings may provide a promising novel target for the treatment of OS.

Comprehensive analysis of metabolism-related lncRNAs related to the progression and prognosis in osteosarcoma from TCGA

Background

Osteosarcoma is one of the most common malignant neoplasms in children and adolescents. Studies have shown that metabolism-related pathways are vital for the development and metastasis of osteosarcoma. Long non-coding RNA (lncRNA) plays a key role in the occurrence and progression of cancer in a variety of ways. However, the detailed molecular mechanisms of metabolism-related lncRNA in osteosarcoma remain to be deeply elucidated.

Methods

In this study, all metabolism-related mRNAs and lncRNAs in osteosarcoma were extracted and identified based on transcriptomic data from the TCGA database. Usingsurvival analysis, univariate and multivariate independent prognostic analysis, gene set enrichment analysis, and nomogram, a prognostic signature with metabolic lncRNAs as prognostic factors was constructed.

Results

Nine prognostic factors included lncRNA AC009779.2, lncRNA AL591895.1, lncRNA AC026271.3, lncRNA LPP-AS2, lncRNA LINC01857, lncRNA AP005264.1, lncRNA LINC02454, lncRNA AL133338.1, and lncRNA AC135178.5, respectively. Survival analysis indicated that alterations of specific lncRNA expression were strongly correlated with poor prognosis in osteosarcoma. Univariate and multivariate independent prognostic analysis showed that the prognostic signature had a good independent predictive ability for patient survival. The results of GSEA suggested that these predictors may be involved in the metabolism of certain substances or energy in cancer. The nomogram was further drawn for clinical guidance and assistance in clinical decision-making.

Conclusions

This study identified multiple metabolism-related lncRNAs, which may be novel therapeutic targets for osteosarcoma, and contributed to better explore the specific metabolic regulatory mechanisms of lncRNA in osteosarcoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02647-4.

Hematopoietic cell kinase enhances osteosarcoma development via the MEK/ERK pathway

Osteosarcoma (OS) is a sarcoma with high rates of pulmonary metastases and mortality. The mechanisms underlying tumour generation and development in OS are not well‐understood. Haematopoietic cell kinase (HCK), a vital member of the Src family of kinase proteins, plays crucial roles in cancer progression and may act as an anticancer target; however, the mechanism by which HCK enhances OS development remains unexplored. Therefore, we investigated the role of HCK in OS development in vitro and in vivo. Downregulation of HCK attenuated OS cell proliferation, migration and invasion and increased OS cell apoptosis, whereas overexpression of HCK enhanced these processes. Mechanistically, HCK expression enhanced OS tumorigenesis via the mitogen‐activated protein kinase (MEK)/extracellular signal‐regulated kinase (ERK) pathway; HCK upregulation increased the phosphorylation of MEK and ERK and promoted epithelial‐mesenchymal transition, with a reduction in E‐cadherin in vitro. Furthermore, HCK downregulation decreased the tumour volume and weight in mice transplanted with OS cells. In conclusion, HCK plays a crucial role in OS tumorigenesis, progression and metastasis via the MEK/ERK pathway, suggesting that HCK is a potential target for developing treatments for OS.

Gold nanorods and nanohydroxyapatite hybrid hydrogel for preventing bone tumor recurrence via postoperative photothermal therapy and bone regeneration promotion

Osteosarcoma is a malignant bone tumor, which often occurs in adolescents. However, surgical resection usually fails to completely remove the tumor clinically, which has been the main cause of postoperative recurrence and metastasis, resulting in the high death rate of patients. At the same time, osteosarcoma invades a large area of the bone defect, which cannot be self-repaired and seriously affects the life quality of the patients. Herein, a bifunctional methacrylated gelatin/methacrylated chondroitin sulfate hydrogel hybrid gold nanorods (GNRs) and nanohydroxyapatite (nHA), which possessed excellent photothermal effect, was constructed to eradicate residual tumor after surgery and bone regeneration. In vitro, K7M2wt cells (a mouse bone tumor cell line) can be efficiently eradicated by photothermal therapy of the hybrid hydrogel. Meanwhile, the hydrogel mimics the extracellular matrix to promote proliferation and osteogenic differentiation of mesenchymal stem cells. The GNRs/nHA hybrid hydrogel was capable of photothermal treatment of postoperative tumors and bone defect repair in a mice model of tibia osteosarcoma. Therefore, the hybrid hydrogel possesses dual functions of tumor therapy and bone regeneration, which shows great potential in curing bone tumors and provides a new hope for tumor-related bone complex disease.

Curcumin-Microsphere/IR820 Hybrid Bifunctional Hydrogels for In Situ Osteosarcoma Chemo-co-Thermal Therapy and Bone Reconstruction

Conventional biomaterial-mediated osteosarcoma therapy mainly focuses on its antitumor effect yet often fails to overcome the problem of post-treatment bone tissue defect repair. Simultaneously, minimally invasive drug delivery methods are becoming spotlights for normal tissue preservation. Herein, an injectable curcumin-microsphere/IR820 coloaded hybrid methylcellulose hydrogel (Cur-MP/IR820 gel) platform was designed for osteosarcoma therapy and bone regeneration. In vitro, the K7M2wt osteosarcoma cells were eradicated by hyperthermia and curcumin. Later, the sustained release of curcumin promoted alkaline phosphatase expression and calcium deposition of bone mesenchymal stem cells. In vivo, this hybrid hydrogel could reach tumor site via injection and turned into hydrogel due to heat sensitivity. Under the irradiation of an 808 nm laser, localized hyperthermia (∼51 °C) generated in 5 min to ablate the tumor. Meanwhile, the thermal-accelerated curcumin release and thermal-increased cell membrane permeability led to tumor cell apoptosis. Tumors in photothermal-co-chemotherapy group were successfully restrained from day 2 after treatment. After that, bone reconstruction was promoted because of sustained released curcumin. The chemo-co-thermal efficacy and osteogenic capacity of Cur-MP/IR820 hydrogel suggest a promising approach to the treatment of osteosarcoma and provide provoking inspiration for treating bone tumors and repairing bone tissue.

The outstanding role of miR-132-3p in carcinogenesis of solid tumors

MicroRNAs are a group of short non-coding RNAs (miRNAs), which are epigenetically involved in gene expression and other cellular biological processes and can be considered as potential biomarkers for cancer detection and support for treatment management. This review aims to amass the evidence to reach the molecular mechanism and clinical significance of miR-132 in different types of cancer. Dysregulation of miR-132 level in various types of malignancies, including hepatocellular carcinoma, breast cancer, colorectal cancer, gastric cancer, lung cancer, prostate cancer, osteosarcoma, pancreatic cancer, and ovarian cancer have reported, significantly decrease in its level, which can be indicated to its function as a tumor suppressor. miR-132 is involved in cell proliferation, migration, and invasion through cell cycle pathways, such as PI3K, TGFβ or hippo signaling pathways, or on oncogenes such as Ras, AKT, mTOR, glycolysis. miR-132 could be potentially a candidate as a valuable biomarker for prognosis in various cancers. Through this study, we proposed that miR-132 can potentially be a candidate as a prognostic marker for early detection of tumor development, progression, as well as metastasis.

Investigation of Mg-xLi-Zn alloys for potential application of biodegradable bone implant materials

Implant therapy after osteosarcoma surgery is a major clinical challenge currently, especially the requirements for mechanical properties, degradability of the implants, and their inhibition of residual tumor cells. Biodegradable magnesium (Mg) alloy as medical bone implant material has full advantages and huge potential development space. Wherein, Mg-lithium (Li) based alloy, as an ultra-light alloy, has good properties for implants under certain conditions, and both Mg and Li have inhibitory effects on tumor cells. Therefore, Mg-Li alloy is expected to be applied in bone implant materials for mechanical supporting and inhibiting tumor cells simultaneously. In this contribution, the Mg-xLi-Zinc (Zn) series alloys (x = 3 wt%, 6 wt%, 9 wt%) were prepared to study the influence of different elements and contents on the structure and properties of the alloy, and the biosafety of the alloy was also evaluated. Our data showed that the yield strength, tensile strength, and elongation of as-cast Mg-xLi-Zn alloy were higher than those of as-cast Mg-Zn alloy; Mg-xLi-Zn alloy can kill osteosarcoma cells (MG-63) in a concentration-dependent manner, wherein Mg-3Li-Zn alloy (x = 3 wt%) and Mg-6Li-Zn alloy (x = 6 wt%) promoted the proliferation of osteoblasts (MC3T3) at a certain concentration of Li. In summary, our study demonstrated that the Mg-6Li-Zn alloy could be potentially applied as a material of orthopedic implant for its excellent multi-functions.

DNA damage response and repair in osteosarcoma: Defects, regulation and therapeutic implications

Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents which has the survival rate of 20% in its advanced stages. Osteosarcomas are mostly resistance to our common treatments. DNA damage response (DDR) is a specialized multistep process containing abundant proteins which are necessary for the survival of any cell and organism. DDR machinery detects a diversity of DNA lesions and inhibits the cell cycle progression if these lesions are not repairable. DDR is involved in aging, age-related diseases, and cancer. In recent years, DDR inhibitors have gained the attention of researches due to their potentials in offering novel therapeutic targets and improving the response of many cancers to either chemo- or radio-therapy. In this regard, we tried to gather a great body of evidence about the role of DDR ingredients in osteosarcoma's initiation/progression, prognosis, and treatment.

Pathogenesis and Current Treatment of Osteosarcoma: Perspectives for Future Therapies

Osteosarcoma is the most common primary malignant bone tumor in children and young adults. The standard-of-care curative treatment for osteosarcoma utilizes doxorubicin, cisplatin, and high-dose methotrexate, a standard that has not changed in more than 40 years. The development of patient-specific therapies requires an in-depth understanding of the unique genetics and biology of the tumor. Here, we discuss the role of normal bone biology in osteosarcomagenesis, highlighting the factors that drive normal osteoblast production, as well as abnormal osteosarcoma development. We then describe the pathology and current standard of care of osteosarcoma. Given the complex heterogeneity of osteosarcoma tumors, we explore the development of novel therapeutics for osteosarcoma that encompass a series of molecular targets. This analysis of pathogenic mechanisms will shed light on promising avenues for future therapeutic research in osteosarcoma.

Noncoding RNAs in osteosarcoma: Implications for drug resistance

Osteosarcoma is the most frequent bone malignancy in children and adolescents. Despite advances of surgery and chemotherapy in osteosarcoma over the past decades, overall survival rates of osteosarcoma have reached a plateau. The development of multi-drug resistance (MDR) has become the main obstacle in improving chemotherapeutic effects in osteosarcoma treatment. Therefore, understanding detailed mechanisms of chemoresistance and developing novel therapeutic targets to overcome chemoresistance are crucial to improve the prognosis of osteosarcoma patients. Accumulating evidence has proved that multiple noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) play pivotal roles in osteosarcoma progression. Notably, a great number of ncRNAs are abnormally expressed and can regulate chemosensitivity through various mechanisms in osteosarcoma. In this review, we systematically summarize the roles of ncRNAs as well as the molecular mechanisms in modulating drug resistance of osteosarcoma and discuss the potential roles of ncRNAs as biomarkers and novel therapeutic targets for osteosarcoma.

The microRNA-424/503 cluster: A master regulator of tumorigenesis and tumor progression with paradoxical roles in cancer

MicroRNAs (miRNAs) are a group of non-coding RNAs that play a crucial role in post-transcriptional gene regulation and act as indispensable mediators in several critical biological processes, including tumorigenesis, tissue homeostasis, and regeneration. MiR-424 and miR-503 are intragenic miRNAs that are clustered on human chromosome Xq26.3. Previous studies have reported that both miRNAs are dysregulated and play crucial but paradoxical roles in tumor initiation and progression, involving different target genes and molecular pathways. Moreover, these two miRNAs are concomitantly expressed in several cancer cells, indicating a coordinating function as a cluster. In this review, the roles and regulatory mechanisms of miR-424, miR-503, and miR-424/503 cluster are summarized in different types of cancers.

An update on the roles of circular RNAs in osteosarcoma

Osteosarcoma is the most common primary bone malignancy and is a neoplasm thought to be derived from the bone‐forming mesenchymal stem cells. Aberrant activation of oncogenes and inactivation of tumour suppressor genes by somatic mutations and epigenetic mechanisms play a pivotal pathogenic role in osteosarcoma. Aside from alterations in these protein‐coding genes, it has now been realized that dysregulation of non‐coding RNAs (ncRNAs), including microRNAs (miRNAs), long non‐coding RNAs (lncRNAs) and the recently discovered circular RNAs (circRNAs), is crucial to the initiation and progression of osteosarcoma. CircRNAs are single‐stranded RNAs that form covalently closed loops and function as an important regulatory element of the genome through multiple machineries. Recently, an increasing number of studies suggested that circRNAs also played critical roles in osteosarcoma. This review summarizes recent development and progression in circRNA transcriptome analysis and their functions in the modulation of osteosarcoma progression.

Clinical management of adolescents and young adults suffering from sarcoma in the French Rhône-Alpes region: A prospective exhaustive cohort with 10 years follow up

INTRODUCTION

Survival of adolescents and young adults (AYA) with sarcoma is lower than in younger patients. The objective of this study was to describe the regional healthcare circuits, the differences in the management between adult, paediatric and mixed units and to assess the prognostic impact of compliance with clinical practice guidelines (CPGs) on overall survival (OS) and on relapse free survival (RFS).

MATERIALS AND METHODS

Retrospective analysis of the management and long term follow-up of all 13-25 year old patients with a sarcoma diagnosed in the Rhône-Alpes area between 2000 and 2005.

RESULTS

140 patients satisfied inclusion criteria and were selected. The majority of 13-25 year old patients were treated in paediatric units. Joint management resulted in a higher rate of discussion in multidisciplinary tumour board, inclusion in clinical trials, and fertility preservation. Non-compliance with guidelines was observed in 65% of cases. Overall compliance was not reported to correlate to survival. Compliance of radiotherapy with CPG's seemed associated with a better prognosis for OS (HR = 0.20, 95% CI = [0.10-0.40]; p < 0.0001) and RFS (HR = 0.18, 95% CI = [0.09-0.37; p < 0.0001) as well as compliance of surgery for OS (HR = 0.43, 95% CI = [0.23-0.81]; p = 0.01). Multivariate Cox regression analysis revealed other independent predictors of OS like age at diagnosis, stage and histological subtype.

CONCLUSIONS

Management of AYA in joint units seems to improve the quality of care. Compliance of surgery and radiotherapy with CGP's seems to improve survival.

MicroRNA-509-3p inhibits cellular migration, invasion, and proliferation, and sensitizes osteosarcoma to cisplatin

Osteosarcoma (OS) is the most common primary pediatric malignancy of the bone having poor prognosis and long-term survival rates of less than 30% in patients with metastasis. MicroRNA-509 was reported to be downregulated in OS. We and others previously published that miR-509-3p can strongly attenuate cellular migration/invasion and sensitize ovarian cancer to cisplatin. Here, we show that overexpression of miR-509-3p inhibited migration of primary OS cell lines U2OS, HOS, and SaOS2 as well as metastatic derivatives 143B and LM7. miR-509-3p overexpression also inhibited proliferation and invasion of HOS and 143B cells and sensitized cells to cisplatin. Luciferase reporter assays using 3'-UTRs of predicted miR-509-3p targets associated with metastatic phenotypes revealed ARHGAP1 could be one of the downstream effectors of miR-509-3p in HOS. To find the global impact of miR-509-3p overexpression and cisplatin treatment we performed Reverse Phase Protein Analysis (RPPA). AXL, which has been reported to play a critical role in cisplatin resistance and confirmed as direct target of miR-509-3p was downregulated upon miR-509-3p treatment and further down-regulated upon miR-509-3p + cisplatin treatment. We propose that the miR-509-3p/AXL and miR-509-3p/ARHGAP1 axes have the potential to uncover new druggable targets for the treatment of drug resistant metastatic osteosarcoma.

A multicentric randomized phase II clinical trial evaluating high-dose thiotepa as adjuvant treatment to standard chemotherapy in patients with resectable relapsed osteosarcoma

BACKGROUND

The role of high-dose chemotherapy in relapsing osteosarcomas has not been established. We evaluated the efficacy and tolerance of high-dose thiotepa (HDTp) after standard chemotherapy (SCT) in patients with relapsed osteosarcoma.

PATIENTS AND METHODS

This randomised open-label phase II study enrolled patients 1-50 years, with local or metastatic relapse of a high-grade osteosarcoma, not progressive after two cycles of SCT, for whom a complete surgery can be achievable following treatment. The trial assigned enrolled patients in a 1:1 ratio to receive two additional courses of SCT + HDTp and autologous transplantation (Arm A), or SCT alone (Arm B). Surgery for complete resection was scheduled as soon as feasible. Primary endpoint was overall survival (OS). Secondary objectives included progression-free survival (PFS) and safety.

RESULTS

From September 2009 to November 2016, 44 patients were randomised (A:22; B:22). In total, 54.5% were males, and the median age was 16 years (9-32years). The two-year OS rate was 66.7% (95% CI 42.5-82.5) (SCT + HDTp, Arm A) versus 50.0% (95% CI 28.2-68.4) for SCT alone (Arm B). Median OS was 27.4 and 24.8 months, respectively (hazard ratio [HR] 0.826, 95% CI 0.393-1.734; p = 0.6123). Median PFS was 15.6 (8.9-24.9) months in Arm A versus 7.2 (4.8-33.3) months in Arm B, p = 0.3845. Among the 22 patients treated with SCT + HDTp, 16 (72.7%) experienced at least one grade ≥3 adverse events versus 18/22 (81.8%) patients treated with SCT. No toxic death occurred.

CONCLUSION

Adjuvant HDTp failed to significantly improve OS and PFS in resectable relapsed osteosarcomas. Despite a trend of prolonged survival and an acceptable toxicity, thiotepa cannot be recommended.

KEY MESSAGE

HDTp and autologous transplantation added to SCT did not improve OS and PFS in patients with resectable relapsed osteosarcomas. Despite a trend of prolonged survival, thiotepa cannot be recommended.

MicroRNA-150 functions as a tumor suppressor and sensitizes osteosarcoma to doxorubicin-induced apoptosis by targeting RUNX2

Osteosarcoma (OS) is the most common form of bone malignancy in children and adolescents. MicroRNAs (miRNAs) have been associated with the development and progression of OS. In the present study, reverse transcription-quantitative PCR, western blotting, Cell Counting Kit-8, luciferase and Transwell assays were performed to investigate the biological function of microRNA-150 (miR-150) in OS. The results revealed that miR-150 was significantly downregulated in OS cell lines (HOS, SAOS2, MG-63 and U2OS) in comparison with the normal osteoblast cells (hFOB1.19). Overexpression of miR-150 significantly inhibited cell proliferation in OS cells. miR-150 could sensitize OS cells to chemotherapy treatment of doxorubicin. Runt-related transcription factor 2 (RUNX2) was identified as a target gene of miR-150. RUNX2 knockdown exhibited similar inhibitory effects on both OS cell proliferation and chemotherapy sensitivity. Restoration of RUNX2 reversed the biological function of miR-150. Finally, miR-150 overexpression and RUNX2 knockdown enhanced caspase-3 cleavage. Taken together, the present study established a novel molecular mechanism, in that miR-150 plays tumor suppressor and chemoprotective roles by targeting RUNX2 in OS, indicating that miR-150 may be a potential therapeutic target for OS therapy in the future.

Doxorubicin·Hydrochloride/Cisplatin-Loaded Hydrogel/Nanosized (2-Hydroxypropyl)-Beta-Cyclodextrin Local Drug-Delivery System for Osteosarcoma Treatment In Vivo

Osteosarcoma (OSA) is a difficult cancer to treat due to its tendency for relapse and metastasis; advanced methods are therefore required for OSA treatment. In this study, we prepared a local drug-delivery system for OSA treatment based on doxorubicin·hydrochloride (DOX·HCl)/cisplatin (CP)-loaded visible light-cured glycol chitosan (GC) hydrogel/(2-hydroxypropyl)-beta-cyclodextrin (GDHCP), and compared its therapeutic efficiency with that of DOX·HCl- and CP-loaded GC hydrogels (GD and GHCP). Because of diffusion driven by concentration gradients in the swollen matrix, the three hydrogels showed sustained releases of DOX·HCl and CP over 7 days, along with initial 3-h bursts. Results of in vitro cell viability and in vivo animal testing revealed that GDHCP had a stronger anticancer effect than GD and GHCP even though there were no significant differences. Body weight measurement and histological evaluations demonstrated that the drug-loaded GC hydrogels had biocompatibility without cardiotoxicity or nephrotoxicity. These results suggested that GDHCP could be a good platform as a local drug-delivery system for clinical use in OSA treatment.

Methotrexate-Etoposide-Ifosfamide Compared with Doxorubicin-Cisplatin-Ifosfamide Chemotherapy in Osteosarcoma Treatment, Patients Aged 18-25 Years

Purpose: The French standard chemotherapy for osteosarcoma combines high-dose methotrexate (HDM) and etoposide-ifosfamide (EI) in children and adolescents, and API-AI (doxorubicin-cisplatin-ifosfamide) in adults. We herein present the results of M-EI and API-AI in 18- to 25-year-old patients. Methods: Patients, 18-25 years old, received either M-EI or API-AI regimens. M-EI comprised seven M and two EI doses preoperatively then M-EI in standard-risk patients (good histological response without metastasis) and five M-AP (methotrexate-doxorubicin-cisplatin) in high-risk patients (poor histological response, metastasis, and/or unresectable primary), postoperatively. API-AI comprised three API and two AI doses preoperatively, then two AI and two PI in standard-risk patients and five EI in high-risk patients, postoperatively. Results: We analyzed 95 patients 18-25 years of age: 55 received M-EI and 40 API-AI. The groups had similar baseline characteristics. Eighty-nine patients (94%) had surgery. Twenty-nine of 55 M-EI patients (60%) and 16/40 API-AI patients (41%) had good histological responses to preoperative chemotherapy. At 5 years, event-free survival was 50% (95% confidence interval [CI]: 39-60) and overall survival was 65% (95% CI: 54-74). Acute toxicity was similar, without treatment-related deaths. Conclusions: Survival outcomes with M-EI and API-AI were not significantly different. Tolerance was acceptable with both regimens. HDM is thus feasible for young adults. However, our study limitations preclude any definitive conclusions.

Primary Bone Tumors: Challenges and Opportunities for CAR-T Therapies

Primary malignant bone tumors are rare, occur in all age groups, and include distinct entities such as osteosarcoma, Ewing sarcoma, and chondrosarcoma. Traditional treatment with some combination of chemotherapy, surgery, and radiation has reached the limit of efficacy, with substantial room for improvement in patient outcome. Furthermore, genomic characterization of these tumors reveals a paucity of actionable molecular targets. Against this backdrop, recent advances in cancer immunotherapy represent a silver lining in the treatment of primary bone cancer. Major strategies in cancer immunotherapy include stimulating naturally occurring anti-tumor T cells and adoptive transfer of tumor-specific cytotoxic T cells. Chimeric antigen receptor T cells (CAR-T cells) belong to the latter strategy and are an impressive application of both insights into T cell biology and advances in genetic engineering. In this review, we briefly describe the CAR-T approach and discuss its applications in primary bone tumors. © 2019 American Society for Bone and Mineral Research.

Polydopamine-based surface modification of paclitaxel nanoparticles for osteosarcoma targeted therapy

In order to achieve the purpose of targeting treatment of osteosarcoma, we developed novel paclitaxel (PTX) nanoparticles (Nps) coated with polydopamine (PDA) and grafted by alendronate (ALN) as ligand. Dopamine can be easily polymerized on various surfaces to form a thin PDA film in alkaline environment, which provided a versatile platform to perform secondary reactions for compounds without functional groups. The targeting Nps had a mean particle size of 290.6 ± 2.2 nm and a zeta potential of -13.4 ± 2.7. It was stable in phosphate buffer saline (PBS, pH 7.4), 5% glucose, plasma and displayed sustained drug release behavior. In vitro assay demonstrated the targeting Nps had stronger cytotoxicity against K₇M₂ wt osteosarcoma cells than the non-targeting Nps. Furthermore, in vivo distribution study indicated they could accumulate much more in tumor than non-targeting Nps. This is consistent with the in vivo antitumor study, targeting Nps achieved a better therapeutic effect than Taxol (8 mg kg^-1, i.v.) (71.85% versus 66.53%) and prominently decreased the side effects of PTX. In general, the PTX-PDA-ALN-Nps may offer a feasible and effective strategy for osteosarcoma targeted therapy.

Upregulation of miR‑95-3p inhibits growth of osteosarcoma by targeting HDGF

Osteosarcoma is the most common bone malignancy and miR-95-3p plays an important role in multiple cancers. The purpose of this study was to explore the effect and potential mechanism of miR-95-3p on the growth of osteosarcoma. In vitro, the osteosarcoma cell lines, SAOS-2 and U2OS cells, were transfected with miR-95-agomir to assess the role of miR-95-3p in proliferation and apoptosis of osteosarcoma cells. We determined that overexpression of miR-95-3p significantly attenuated cell proliferation but enhanced apoptosis in SAOS-2 and U2OS cells. We also found that overexpression of miR-95-3p in osteosarcoma cells downregulated the expression of hepatoma-derived growth factor (HDGF). Next, knockdown of HDGF by siRNA targeting HDGF clearly inhibited cell proliferation and induced apoptosis in U2OS cells. In vivo, a tumor formation assay in BALB/c nude mice was conducted by injecting the pre-miR-95 or control vector lentivirus-infected U2OS cells to determine the effect of miR-95-3p on the growth of osteosarcoma. Results showed miR-95-3p overexpression inhibited the osteosarcoma growth and downregulated the HDGF expression in xenografted tumor. For mechanism study, we co-transfected HDGF/pcDNA3.1 plasmid and miR-95-agomir to U2OS cells, and we demonstrated that overexpression of HDGF could attenuate the effects of miR-95-3p on U2OS cell proliferation, apoptosis and migration. These findings indicated that miR-95-3p might act as a potential tumor suppressor in osteosarcoma by targeting HDGF. Thus, miR-95-3p may become a potential therapeutic in treatment of osteosarcoma.

Incidence and mortality of bone cancer among children, adolescents and young adults of Brazil

OBJECTIVES

Bone cancers occur frequently in children, adolescents, and young adults aging 15 to 29 years. Osteosarcoma and Ewing sarcoma are the most frequent subtypes in this population. The aim of this study was to describe incidence and mortality trends of bone cancers among Brazilian children, adolescents and young adults.

METHODS

Incidence information was obtained from 23 population-based cancer registries. Mortality data were extracted from the Atlas of Cancer Mortality from 1979 to 2013. Specific and adjusted rates per million were analyzed according to gender, morphology and age at diagnosis. Median rates were used as a measure of central tendency. Joinpoint regression was applied to analyze trends.

RESULTS

Median incidence rates were 5.74 and 11.25 cases per million in children and young adults respectively. Osteosarcoma in the 15-19 years aged group had the highest incidence rates. Stable incidence rates were observed among five registries in 0-14 year's age group. Four registries had a decreased incidence trend among adolescents and young adults. Median mortality rates were 1.22 and 5.07 deaths per million in children and young adults respectively. Increased mortality was observed on the North and Northeast regions. Decreased mortality trends were seen in the South (children) and Southeast (adolescents and young adults).

CONCLUSION

Osteosarcoma and Ewing Sarcoma are the most incident bone cancers in all Brazilian regions. Bone cancers showed incidence and mortality patterns variation within the geographic regions and across age groups, although not significant. Despite limitations, it is crucial to monitor cancer epidemiology trends across geographic Brazilian regions.

Exploration of TiO2 nanoparticle mediated microdynamic therapy on cancer treatment

Radical therapy takes advantage of the reactive oxygen species produced in greater quantities within tumor cells than in normal cells. Here, for the first time, we explore a TiO₂ nanoparticle mediated microwave induced radical therapy (termed as Microdynamic Therapy) as a new cancer treatment method. The experiments in vitro and in vivo demonstrate that colloidal TiO₂ nanoparticles could significantly suppress the growth of osteosarcomas, even under low power (5 W) microwave (MW) irradiation for 5 min. The high photocatalytic activity of TiO₂ nanoparticles efficiently utilizes the microwave-induced plasmonic effect for the formation of reactive oxygen species (ROS). Furthermore, TiO₂ nanoparticles exhibit a higher cytotoxicity on cancer cells (osteosarcoma UMR-106 cells) than on normal cells (mouse fibroblast L929 cells). The effectiveness of TiO₂ nanoparticles for microwave induced radical therapy demonstrates that this is a new landmark approach to treating cancers.

Abemaciclib Is Active in Preclinical Models of Ewing Sarcoma via Multipronged Regulation of Cell Cycle, DNA Methylation, and Interferon Pathway Signaling

PURPOSE

Ewing sarcoma (ES) is a rare and highly malignant cancer that occurs in the bone and surrounding tissue of children and adolescents. The EWS/ETS fusion transcription factor that drives ES pathobiology was previously demonstrated to modulate cyclin D1 expression. In this study, we evaluated abemaciclib, a small-molecule CDK4 and CDK6 (CDK4 and 6) inhibitor currently under clinical investigation in pediatric solid tumors, in preclinical models of ES.

EXPERIMENTAL DESIGN

Using Western blot, high-content imaging, flow cytometry, ELISA, RNA sequencing, and CpG methylation assays, we characterized the in vitro response of ES cell lines to abemaciclib. We then evaluated abemaciclib in vivo in cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) mouse models of ES as either a monotherapy or in combination with chemotherapy.

RESULTS

Abemaciclib induced quiescence in ES cell lines via a G₁ cell-cycle block, characterized by decreased proliferation and reduction of Ki-67 and FOXM1 expression and retinoblastoma protein (RB) phosphorylation. In addition, abemaciclib reduced DNMT1 expression and promoted an inflammatory immune response as measured by cytokine secretion, antigen presentation, and interferon pathway upregulation. Single-agent abemaciclib reduced ES tumor volume in preclinical mouse models and, when given in combination with doxorubicin or temozolomide plus irinotecan, durable disease control was observed.

CONCLUSIONS

Collectively, our data demonstrate that the antitumor effects of abemaciclib in preclinical ES models are multifaceted and include cell-cycle inhibition, DNA demethylation, and immunogenic changes.

Sox2 is required for tumor development and cancer cell proliferation in osteosarcoma

The stem cell transcription factor Sox2 is highly expressed in many cancers where it is thought to mark cancer stem cells (CSC). In osteosarcomas, the most common bone malignancy, high Sox2 expression marks and maintains a fraction of tumor initiating cells that show all the properties of CSC. Knock down of Sox2 expression abolishes tumorigenicity and suppresses the CSC phenotype. Here we show that, in a mouse model of osteosarcoma, osteoblast-specific Sox2 conditional knockout (CKO) causes a drastic reduction in the frequency and onset of tumors. The rare tumors detected in the Sox2 CKO animals were all Sox2 positive, indicating that they arose from cells that had escaped Sox2 deletion. Furthermore Sox2 inactivation in cultured osteosarcoma cells by CRISPR/CAS technology leads to a loss of viability and proliferation of the entire cell population. Inactivation of the YAP gene, a major Hippo Pathway effector which is a direct Sox2 target, causes similar results and YAP overexpression rescues cells from the lethality caused by Sox2 inactivation. These effects were osteosarcoma-specific, suggesting a mechanism of cell “addiction” to Sox2 initiated pathways. The requirement for Sox2 for osteosarcoma formation as well as for the survival of the tumor cells suggests that disruption of Sox2-initiated pathways could be an effective strategy for the treatment of osteosarcoma.

PPARγ agonists promote differentiation of cancer stem cells by restraining YAP transcriptional activity

Osteosarcoma (OS) is a highly aggressive pediatric bone cancer in which most tumor cells remain immature and fail to differentiate into bone-forming osteoblasts. However, OS cells readily respond to adipogenic stimuli suggesting they retain mesenchymal stem cell-like properties. Here we demonstrate that nuclear receptor PPARγ agonists such as the anti-diabetic, thiazolidinedione (TZD) drugs induce growth arrest and cause adipogenic differentiation in human, mouse and canine OS cells as well as in tumors in mice. Gene expression analysis reveals that TZDs induce lipid metabolism pathways while suppressing targets of the Hippo-YAP pathway, Wnt signaling and cancer-related proliferation pathways. Significantly, TZD action appears to be restricted to the high Sox2 expressing cancer stem cell population and is dependent on PPARγ expression. TZDs also affect growth and cell fate by causing the cytoplasmic sequestration of the transcription factors SOX2 and YAP that are required for tumorigenicity. Finally, we identify a TZD-regulated gene signature based on Wnt/Hippo target genes and PPARγ that predicts patient outcomes. Together, this work highlights a novel connection between PPARγ agonist in inducing adipogenesis and mimicking the tumor suppressive hippo pathway. It also illustrates the potential of drug repurposing for TZD-based differentiation therapy for osteosarcoma.

SOX6 is downregulated in osteosarcoma and suppresses the migration, invasion and epithelial-mesenchymal transition via TWIST1 regulation

Transcription factor SOX6 (SOX6) has been reported to serve essential roles in numerous types of cancers. However, the expression and functions of SOX6 in osteosarcoma (OS) have not been analyzed. In the present study, the patterns of SOX6 expression in OS cell lines and tissues were investigated by reverse transcription‑quantitative polymerase chain reaction and western blotting. The results of the present study revealed that SOX6 was notably downregulated in OS tissues and cell lines. Subsequently, gain‑ and loss‑of‑function studies demonstrated that SOX6 inhibited OS cell migration and invasion. In addition, SOX6 may have suppressed epithelial‑mesenchymal transition via twist‑related protein 1 (TWIST1) modulation. Chromatin immunoprecipitation (ChIP), quantitative ChIP and dual luciferase activity assays were used to confirm the binding of SOX6 to the promoter region of TWIST1. Additionally, colony formation assays and Cell Counting Kit‑8 assays demonstrated that SOX6 suppressed cell proliferation. The findings of the present study indicated that SOX6 serves as a tumor suppressor in OS and may be a potential therapeutic target for OS.

PAK5 overexpression is associated with lung metastasis in osteosarcoma

p21-activated kinases (PAKs) are multifunctional effectors of Rho GTPases, which are associated with cytoskeletal organization, cellular morphogenesis, migration and survival. PAKs are overactive in a number of tumor tissues and have attracted attention as a potential target for cancer therapy. In the present study, PAK5 levels were analyzed in primary osteosarcoma (OS) samples (n=65) using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) methods. In the primary OS tissue, increased PAK5 expression (IHC score >2, n=37) was associated with significantly decreased overall survival (P=0.036) compared with decreased PAK5 expression (IHC score ≤2, n=28). PAK5 expression was identified to be significantly associated with metastasis (P=0.010). The lung is the most common metastasis site for OS. In addition, the level of PAK5 in lung metastasis tissue (n=13) was detected using RT-qPCR and IHC methods. PAK5 expression was increased in lung metastasis tissue compared with in primary OS samples. PAK5 was silenced using short hairpin RNA in OS cell lines. Wound healing, migration and nude mice model assay results consistently demonstrated that PAK5 knockdown was able to significantly inhibit OS migration. In PAK5-knockdown cells, the alteration in the expression of a number of metastasis-associated factors, including epithelial cadherin, vimentin, fibronectin and matrix metalloproteinase 2 (MMP2), was analyzed. Only MMP2 expression was decreased significantly (P<0.05). The expression level of MMP2 was analyzed in primary OS tissue and lung metastasis tissue using RT-qPCR and IHC methods. Expression of MMP2 was identified to be associated with expression of PAK5. The results of the present study suggest that PAK5 promotes OS cell migration and that PAK5 expression may be used to predict lung metastasis.

Paeoniflorin induces G2/M cell cycle arrest and caspase-dependent apoptosis through the upregulation of Bcl-2 X-associated protein and downregulation of B-cell lymphoma 2 in human osteosarcoma cells

Paeoniflorin (PF), extracted from the peony root, has been proved to possess antineoplastic activity in different cancer cell lines. However, it remains unclear whether PF has an antineoplastic effect against osteosarcoma cells. The present study investigated the effects and the specific mechanism of PF on various human osteosarcoma cell lines. Using the multiple methods to detect the activity of PF on HOS and Saos-2 human osteosarcoma cell lines, including an MTS assay, flow cytometry, transmission electron microscopy and western blotting, it was demonstrated that PF induces inhibition of proliferation, G2/M phase cell cycle arrest and apoptosis in the osteosarcoma cell lines in vitro, and activation of cleaved-caspase-3 and cleaved-poly (ADPribose) polymerase in a dose-dependent manner. Furthermore, the pro-apoptotic factors Bcl-2 X-associated protein and BH3 interacting domain death agonist were uregulated, while the anti-apoptotic factors B-cell lymphoma 2 (Bcl-2) and Bcl-2-extra large were downregulated. In conclusion, these results demonstrated that PF has a promising therapeutic potential in for osteosarcoma.

ATF4 regulated by MYC has an important function in anoikis resistance in human osteosarcoma cells

Anoikis resistance is a crucial step in the process of tumor metastasis. This step determines whether the tumor cells will survive when they become detached from the extracellular matrix. However, the specific mechanism of tumor cells to bypass anoikis and become resistant remains to be elucidated. The present study aimed to determine the internal mechanism of bypassing anoikis through comparison of human osteosarcoma cell lines with human normal cell lines. High activating transcription factor 4 (ATF4) and myelocytomatosis oncogene (MYC) expression levels were observed in MG-63 and U-2 OS human osteosarcoma cell lines. It is possible that ATF4 and MYC contribute to tumor progression. Subsequently, the expression levels of ATF4 and MYC in HUVEC and CHON-001 human normal cell lines were upregulated and their adhesion abilities were reduced; whereas their ability to bypass anoikis increased significantly. Simultaneously, after we Following a knock-down of ATF4 and MYC expression levels in MG-63 and U-2 OS human osteosarcoma cell lines, their adhesion ability increased and their ability to bypassing anoikis was significantly reduced. Upregulation of MYC resulted in an upregulation of ATF4, and chromatin immunoprecipitation and luciferase reporter gene technology demonstrated that MYC binds to the promoter of ATF4. These findings suggest that ATF4 regulated by MYC might contribute to resistance to anoikis in human osteosarcoma cells.

Tetrahydrocurcumin induces mesenchymal-epithelial transition and suppresses angiogenesis by targeting HIF-1α and autophagy in human osteosarcoma

Human osteosarcoma is considered a malignant tumor with poor prognosis that readily metastasizes. Tetrahydrocurcumin (THC) has been reported to have anti-tumor activity in numerous tumors. In addition, hypoxia-inducible factor-1α (HIF-1α) has been demonstrated to be associated with tumor metastasis by regulating epithelial-mesenchymal transition (EMT). However, the role of THC in osteosarcoma remains uncertain. Therefore, this study aimed to elucidate the potential mechanisms. We found that THC significantly reduced the growth of osteosarcoma cells and suppressed migration and invasion, as tested in a nude mouse lung metastasis model. Additionally, the mesenchymal-epithelial transition (MET) process was facilitated by THC. Mechanistically, our study showed that HIF-1α had a pivotal role in the anti-metastatic effect of THC. Importantly, HIF-1α expression was downregulated by THC by inhibiting Akt/mTOR and p38 MAPK pathways. Moreover, THC exhibited a remarkable inhibitory effect on HIF-1α expression and angiogenesis under hypoxic conditions. Furthermore, THC activated autophagy and induced MET and suppressed angiogenesis in a HIF-1α-related manner. Taken together, our findings suggest that THC suppresses metastasis and invasion and this may be associated with HIF-1α and autophagy, which would potentially provide therapeutic strategies for human osteosarcoma.

Foscan and foslip based photodynamic therapy in osteosarcoma in vitro and in intratibial mouse models

Current osteosarcoma therapies cause severe treatment-related side effects and chemoresistance, and have low success rates. Consequently, alternative treatment options are urgently needed. Photodynamic therapy (PDT) is a minimally invasive, local therapy with proven clinical efficacy for a variety of tumor types. PDT is cytotoxic, provokes anti-vascular effects and stimulates tumor cell targeting mechanisms of the immune system and, consequently, has potential as a novel therapy for osteosarcoma patients. This study investigated the uptake and the dark- and phototoxicity and cytotoxic mechanisms of the photosensitizer (PS) 5,10,15,20-tetrakis(meta-hydroxyphenyl) chlorine (mTHPC, Foscan) and a liposomal mTHPC formulation (Foslip) in the human 143B and a mouse K7M2-derived osteosaroma cell line (K7M2L2) in vitro. Second, the tumor- and metastasis-suppressive efficacies of mTHPC formulations based PDT and associated mechanisms in intratibial, metastasizing osteosarcoma mouse models (143B/SCID and syngeneic K7M2L2/BALB/c) were studied. The uptake of Foscan and Foslip in vitro was time- and dose-dependent and resulted in mTHPC and light dose-dependent phototoxicity associated with apoptosis. In vivo, the uptake of both i.v. administered mTHPC formulations was higher in tumor than in healthy control tissue. PDT caused significant (Foscan p < 0.05, Foslip p < 0.001) tumor growth inhibition in both models. A significant (Foscan p < 0.001, Foslip p < 0.001) immune system-dependent suppression of lung metastasis was only observed in the K7M2L2/BALB/c model and was associated with a marked infiltration of T-lymphocytes at the primary tumor site. In conclusion, mTHPC-based PDT is effective in clinically relevant experimental osteosarcoma and suppresses lung metastasis in immunocompetent mice with beneficial effects of the liposomal mTHPC formulation Foslip.

Knockdown of Long Noncoding RNA TUG1 Inhibits the Proliferation and Cellular Invasion of Osteosarcoma Cells by Sponging miR-153

Long noncoding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) has been confirmed to be involved in the progression of various cancers; however, its mechanism of action in osteosarcoma has not been well addressed. In our study, TUG1 was overexpressed and miR-153 was downregulated in osteosarcoma tissues and cell lines. A loss-of-function assay showed that TUG1 knockdown suppressed the viability, colony formation, and invasion of osteosarcoma cells in vitro. Moreover, TUG1 was confirmed to be an miR-153 sponge. Ectopic expression of TUG1 reversed the inhibitory effect of miR-153 on the proliferation and invasion of osteosarcoma cells. Further transplantation experiments proved the carcinogenesis of TUG1 in osteosarcoma in vivo. Collectively, our study elucidated that TUG1 contributes to the development of osteosarcoma by sponging miR-153. These findings may provide a novel lncRNA-targeted therapy for patients with osteosarcoma.

Heat shock transcription factor 1 promotes the proliferation, migration and invasion of osteosarcoma cells

OBJECTIVES

Osteosarcoma is the most commonly diagnosed primary malignancy of bone and its overall survival rate is still very low. The molecular mechanisms underlying the progression of osteosarcoma have not been clearly illuminated. Heat shock transcription factor 1 (HSF1) is a key regulator of the heat shock response and also plays important roles in many cancers, but its function in osteosarcoma remains unexplored.

MATERIALS AND METHODS

In this study, the proliferation of osteosarcoma cells was determined by Cell Counting Kit-8 assays and colony formation assays. Transwell assays were used to demonstrate the migration and invasion abilities of osteosarcoma cells. A tumour formation assay in a nude mouse model was performed to assess the effect of HSF1 on osteosarcoma cell growth in vivo. The protein levels of HSF1 were analysed with immunohistochemical staining in samples from osteosarcoma patients.

RESULTS

We demonstrated that knockdown of HSF1 reduced the proliferation, migration and invasion of osteosarcoma cells, while overexpression of HSF1 promoted the proliferation, migration and invasion of osteosarcoma cells. Furthermore, HSF1 promoted the proliferation of osteosarcoma cells in vivo. In addition, high levels of HSF1 were associated with a poor prognosis in osteosarcoma.

CONCLUSIONS

These data highlight an important role of HSF1 in proliferation, migration and invasion of osteosarcoma cells. Moreover, the expression of HSF1 was associated with prognosis in osteosarcoma.