Therapeutic Targets for Bone and Soft-Tissue Sarcomas

Precision Oncology in Soft Tissue Sarcomas and Gastrointestinal Stromal Tumors

Soft tissue sarcomas (STSs), including gastrointestinal stromal tumors (GISTs), are mesenchymal neoplasms with heterogeneous clinical behavior and represent broad categories comprising multiple distinct biologic entities. Multidisciplinary management of these rare tumors is critical. To date, multiple studies have outlined the importance of biological characterization of mesenchymal tumors and have identified key molecular alterations which drive tumor biology. GIST has represented a flagship for targeted therapy in solid tumors with the advent of imatinib which has revolutionized the way we treat this malignancy. Herein, the authors discuss the importance of biological and molecular diagnostics in managing STS and GIST patients.

Trabectedin and Lurbinectedin Modulate the Interplay between Cells in the Tumour Microenvironment-Progresses in Their Use in Combined Cancer Therapy

Trabectedin (TRB) and Lurbinectedin (LUR) are alkaloid compounds originally isolated from Ecteinascidia turbinata with proven antitumoral activity. Both molecules are structural analogues that differ on the tetrahydroisoquinoline moiety of the C subunit in TRB, which is replaced by a tetrahydro-β-carboline in LUR. TRB is indicated for patients with relapsed ovarian cancer in combination with pegylated liposomal doxorubicin, as well as for advanced soft tissue sarcoma in adults in monotherapy. LUR was approved by the FDA in 2020 to treat metastatic small cell lung cancer. Herein, we systematically summarise the origin and structure of TRB and LUR, as well as the molecular mechanisms that they trigger to induce cell death in tumoral cells and supporting stroma cells of the tumoral microenvironment, and how these compounds regulate immune cell function and fate. Finally, the novel therapeutic venues that are currently under exploration, in combination with a plethora of different immunotherapeutic strategies or specific molecular-targeted inhibitors, are reviewed, with particular emphasis on the usage of immune checkpoint inhibitors, or other bioactive molecules that have shown synergistic effects in terms of tumour regression and ablation. These approaches intend to tackle the complexity of managing cancer patients in the context of precision medicine and the application of tailor-made strategies aiming at the reduction of undesired side effects.

Predicting prognosis and immune status in sarcomas by identifying necroptosis-related lncRNAs

BACKGROUND

Sarcomas are a type of highly heterogeneous malignant tumors originating from mesenchymal tissues. Necroptosis is intricately connected to the oncogenesis and progression of tumors. The main goal of this research is to assess the prognostic value of necroptosis-related lncRNAs (NRlncRNAs) in sarcomas and to develop a risk model based on NRlncRNAs to evaluate prognostic and immune status of the sarcomas.

METHODS

We screened NRlncRNAs using the gene co-expression network, developed a prognostic risk model of sarcomas, and then verified the model. Following that, various bioinformatics analysis algorithms were employed to analyze the distinct characteristics of patients of the risk model. Furthermore, the function and regulatory mechanism of NRlncRNA SNHG6 in sarcomas were investigated through osteosarcoma cell experiments, such as qRT-PCR, Western blot, CCK-8, clone formation, and transwell assay.

RESULTS

We successfully developed a NRlncRNAs-related prognostic risk model and screened 5 prognosis-related NRlncRNAs, with SNGH6 being the most significant for prognosis of patients. According to results, the significant differences exist in prognosis, clinical characteristics, and tumor immune status among patients of the risk model. The experiments of osteosarcoma cells demonstrated that NRlncRNA SNHG6 knockdown significantly attenuated the cells' proliferation, migration, and invasion. qRT-PCR and WB results showed that SNHG6 regulated AXL and AKT signaling.

CONCLUSIONS

We have developed an innovative investigation on NRlncRNAs, which can serve as a reference for diagnosis, therapy, and prognosis of sarcomas. Additionally, we demonstrated that NRlncRNA SNHG6 regulated AXL and AKT signaling in osteosarcoma cells and the proliferation, migration, and invasion of tumor cells.

Identification of TNFRSF1A as a potential biomarker for osteosarcoma

BACKGROUND

Osteosarcoma (OS) is a relatively rare malignant bone tumor in teenagers; however, its molecular mechanisms are not yet understood comprehensively.

OBJECTIVE

The study aimed to use necroptosis-related genes (NRGs) and their relationships with immune-related genes to construct a prognostic signature for OS.

METHODS

TARGET-OS was used as the training dataset, and GSE 16091 and GSE 21257 were used as the validation datasets. Univariate regression, survival analysis, and Kaplan-Meier curves were used to screen for hub genes. The immune-related targets were screened using immune infiltration assays and immune checkpoints. The results were validated using nomogram and decision curve analyses (DCA).

RESULTS

Using univariate Cox regression analysis, TNFRSF1A was screened from 14 NRGs as an OS prognostic signature. Functional enrichment was analyzed based on the median expression of TNFRSF1A. The prognosis of the TNFRSF1A low-expression group in the Kaplan-Meier curve was notably worse. Immunohistochemistry analysis showed that the number of activated T cells and tumor purity increased considerably. Furthermore, the immune checkpoint lymphocyte activation gene 3 (LAG-3) is a possible target for intervention. The nomogram accurately predicted 1-, 3-, and 5-year survival rates. DCA validated the model (C = 0.669).

Conclusion

TNFRSF1A can be used to elucidate the potential relationship between the immune microenvironment and NRGs in OS pathogenesis.

The expression changes of PD-L1 and immune response mediators are related to the severity of primary bone tumors

The expression pattern, diagnostic value, and association of PD-L1, IFN-γ and TGF-β with bone tumor type, severity, and relapse are determined in this study. 300 human samples from patients with osteosarcoma, Ewing sarcoma, and GCT were enrolled. The PD-L1 gene and protein expression were assessed by qRT-PCR and immunohistochemistry, respectively. ELISA and flow cytometry was used to detect cytokines and CD4/CD8 T cell percentages, respectively. A considerable increase in PD-L1 level was detected in bone tumor tissues at both gene and protein levels that was considerable in osteosarcoma and Ewing sarcoma. A positive correlation was detected regarding the PD-L1 and tumor metastasis and recurrence in osteosarcoma and Ewing sarcoma. The increased IFN-γ level was detected in patients with metastatic, and recurrent osteosarcoma tumors that were in accordance with the level of TGF-β in these samples. The simultaneous elevation of IFN-γ and TGF-β was detected in Ewing sarcoma and GCT, also the CD4 + /CD8 + ratio was decreased significantly in patients with osteosarcoma compared to GCT tumors. The elevated levels of PD-L1, TGF- β, and IFN-γ were associated with bone tumor severity that can provide insights into the possible role of this axis in promoting immune system escape, suppression, and tumor invasion.

Special Issue: "Pediatric Orthopedic Malignancy: Types, Symptoms, and Treatment"

Pediatric orthopedic malignancies are extremely rare and require appropriate diagnosis and treatment by a multidisciplinary team [...].

Combination of Everolimus and Bortezomib Inhibits the Growth and Metastasis of Bone and Soft Tissue Sarcomas via JNK/p38/ERK MAPK and AKT Pathways

The combination of the mammalian target of rapamycin and proteasome inhibitors is a new treatment strategy for various tumors. Herein, we investigated the synergistic effect of everolimus and bortezomib on tumor growth and metastasis in bone and soft tissue sarcomas. The antitumor effects of everolimus and bortezomib were assessed in a human fibrosarcoma (FS) cell line (HT1080) and mouse osteosarcoma (OS) cell line (LM8) by MTS assays and Western blotting. The effects of everolimus and bortezomib on HT1080 and LM8 tumor growth in xenograft mouse models were evaluated using tumor volume and the number of metastatic nodes of the resected lungs. Immunohistochemistry was used to evaluate cleaved PARP expression. The combination therapy decreased FS and OS cell proliferation compared with either drug alone. This combination induced more intense p-p38, p-JNK, and p-ERK and activated apoptosis signals, such as caspase-3, compared with single-agent treatment. The combination treatment reduced p-AKT and MYC expression, decreased FS and OS tumor volumes, and suppressed lung metastases of OS. The combination therapy inhibited tumor growth in FS and OS and metastatic progression of OS via the JNK/p38/ERK MAPK and AKT pathways. These results could aid in the development of new therapeutic strategies for sarcomas.

EVI2B Is a Prognostic Biomarker and Is Correlated with Monocyte and Macrophage Infiltration in Osteosarcoma Based on an Integrative Analysis

Osteosarcoma (OS) is the most common malignant bone tumor. However, treatment strategies have not changed over the past 30 years. The relationship between OS and the immune microenvironment may provide a basis for the establishment of novel therapeutic targets. In this study, a large-scale gene expression dataset (GSE42352) was used to identify key genes in OS. A Target-OS dataset from the Cancer Genome Atlas was used as a validation set. Ecotropic viral integration site 2B (EVI2B) was significantly upregulated in OS tumor samples. Differentially expressed genes (DEGs) were identified between samples with high and low EVI2B expression in both the test and validation cohorts. The top three functions of DEGs determined by a gene set enrichment analysis (GSEA) were chemokine signaling, cytokine-cytokine receptor interaction, and Human T-cell leukemia virus 1 infection. A prognostic prediction model including EVI2B, DOCK2, and CD33 was constructed by a Cox regression analysis. This model indicated that EVI2B is an independent protective prognostic marker in OS. An analysis of immune infiltration further showed that high EVI2B expression levels were correlated with high levels of macrophage infiltration. Protein expression data derived from the Human Protein Atlas suggested EVI2B to be highly expressed in monocytes. Finally, we validated the elevated expression of EVI2B in OS cell lines and OS tissue samples; these results were consistent with those of the analyses of the GSE42352 and Target-OS datasets. Our integrative bioinformatics analysis and experimental results provide clear evidence for the prognostic value of EVI2B in OS and its close relationship with monocyte and macrophage infiltration.

Trends in Overall Survival among Patients Treated for Sarcoma at a Large Tertiary Cancer Center between 1986 and 2014

Sarcomas are relatively rare malignancies accounting for about 1% of all cancer diagnoses. Studies on sarcomas comprising large cohorts covering extended time periods are lacking. Therefore, this study aimed to evaluate the impact of demographic, behavioral, and clinical characteristics on overall survival (OS) among individuals diagnosed with soft tissue sarcoma (STS) or bone sarcoma at the Moffitt Cancer Center between 1986 and 2014. Unadjusted and multivariable Cox proportional hazard regression (CPHR) models were constructed to generate hazard ratios (HRs) and 95% confidence intervals (CIs) to evaluate associations between a range of demographic, behavioral, and clinical characteristics, and OS. Additionally, Kaplan-Meier survival curves, associated log-rank statistics, and adjusted CPHR models were generated by time periods based on the year of first contact (1986-1994, 1995-1999, 2000-2005, 2006-2010, 2011-2014) to evaluate for temporal differences in OS. Of the 2570 patients, 2037 were diagnosed with STS, whereas 533 were diagnosed with bone sarcoma. At the time of analysis, 50% of the population were alive. In multivariable analyses, we observed poorer survival for patients ≥ 40 years of age (HR = 1.54, 95% CI = 1.34-1.78), current smokers (HR = 1.18, 95% CI = 1.01-1.37), patients with metastasis (HR = 2.19, 95% CI = 1.95-2.47), and patients not receiving first-line surgery treatment (HR = 2.11, 95% CI = 1.82-2.45). We discovered limited improvements in OS over time among individuals diagnosed with STS or bone sarcomas with the exception of gastrointestinal stromal tumors (GIST), which showed a significant improvement in OS across time periods (p = 0.0034). Overall, we identified well-established characteristics associated with OS (e.g., metastasis) in addition to factors (e.g., smoking status) not previously reported to impact OS. Improvements in survival over time have been relatively modest, suggesting the need for improved therapeutic options, especially for those diagnosed with less frequent sarcomas.

EZH2/hSULF1 axis mediates receptor tyrosine kinase signaling to shape cartilage tumor progression

Chondrosarcomas are primary cancers of cartilaginous tissue and capable of alteration to highly aggressive, metastatic, and treatment-refractory states, leading to a poor prognosis with a five-year survival rate at 11 months for dedifferentiated subtype. At present, the surgical resection of chondrosarcoma is the only effective treatment, and no other treatment options including targeted therapies, conventional chemotherapies, or immunotherapies are available for these patients. Here, we identify a signal pathway way involving EZH2/SULF1/cMET axis that contributes to malignancy of chondrosarcoma and provides a potential therapeutic option for the disease. A non-biased chromatin immunoprecipitation sequence, cDNA microarray analysis, and validation of chondrosarcoma cell lines identified sulfatase 1 (SULF1) as the top EZH2-targeted gene to regulate chondrosarcoma progression. Overexpressed EZH2 resulted in downregulation of SULF1 in chondrosarcoma cell lines, which in turn activated cMET pathway. Pharmaceutical inhibition of cMET or genetically silenced cMET pathway significantly retards the chondrosarcoma growth and extends mice survival. The regulation of EZH2/SULF1/cMET axis were further validated in patient samples with chondrosarcoma. The results not only established a signal pathway promoting malignancy of chondrosarcoma but also provided a therapeutic potential for further development of effective target therapy to treat chondrosarcoma.

The Role of a Multidisciplinary Team in the Diagnosis and Treatment of Bone and Soft Tissue Sarcomas: A Single-Center Experience

Bone and soft tissue sarcomas with complex and varied clinical, imaging, and pathological characteristics cannot be diagnosed and treated by a single discipline, as each discipline has some limitations. This study aimed to explore the role of a multidisciplinary team (MDT) in the diagnosis and treatment of bone and soft tissue sarcomas over the past four consecutive years. The subjects were 269 patients discussed during MDT meetings at a Bone and Soft Tissue Sarcomas Center in South China. The diagnosis, relapse diagnosis, unplanned resection, management of pulmonary nodules, and treatment of refractory and advanced tumors were compared to similar data provided in the literature to (i) determine whether the MDT significantly affected the diagnosis and treatment of bone and soft tissue sarcomas, and (ii) explore trends in the types of patients with bone and soft tissue sarcomas and treatment decision-making since the establishment of the MDT. Results revealed that the MDT significantly improved preoperative diagnostic accuracy for patients with bone and soft tissue sarcomas; the accuracy of diagnosis and relapse diagnosis by the MDT reached 95.42% and 100%, respectively. After an MDT discussion, the positive pathology rate for extended resection after unplanned resection was 81.2%. The overall accuracy of the MDT in determining the nature of pulmonary nodules was 87.1-91.9%. For patients presenting with pulmonary nodules in osteosarcoma, no statistically significant difference in survival was shown between cases discussed by the MDT and those without an MDT discussion (p = 0.5751). Collectively, the MDT can play a positive role in accurate preoperative diagnosis, relapse diagnosis, the decision to extend resection after an unplanned resection, and the diagnostic accuracy of pulmonary nodules.

Targeted therapies and checkpoint inhibitors in sarcoma

Sarcomas are defined as a group of mesenchymal malignancies with over 100 heterogeneous subtypes. As a rare and difficult to diagnose entity, micrometastasis is already present at the time of diagnosis in many cases. Current treatment practice of sarcomas consists mainly of surgery, (neo)adjuvant chemo- and/or radiotherapy. Although the past decade has shown that particular genetic abnormalities can promote the development of sarcomas, such as translocations, gain-of-function mutations, amplifications or tumor suppressor gene losses, these insights have not led to established alternative treatment strategies so far. Novel therapeutic concepts with immunotherapy at its forefront have experienced some remarkable success in different solid tumors while their impact in sarcoma remains limited. In this review, the most common immunotherapy strategies in sarcomas, such as immune checkpoint inhibitors, targeted therapy and cytokine therapy are concisely discussed. The programmed cell death (PD)-1/PD-1L axis and apoptosis-inducing cytokines, such as TNF-related apoptosis-inducing ligand (TRAIL), have not yielded the same success like in other solid tumors. However, in certain sarcoma subtypes, e.g. liposarcoma or undifferentiated pleomorphic sarcoma, encouraging results in some cases when employing immune checkpoint inhibitors in combination with other treatment options were found. Moreover, newer strategies such as the targeted therapy against the ancient cytokine macrophage migration inhibitory factor (MIF) may represent an interesting approach worth investigation in the future.

Bacterial extracellular vesicles-based therapeutic strategies for bone and soft tissue tumors therapy

Bone and soft tissue tumors are complex mesenchymal neoplasms that seriously endanger human health. Over the past decade, the relationship between microorganisms and human health and diseases is getting more attention. The extracellular vesicles derived from bacteria have been shown to regulate bacterial-host cell communication by transferring their contents, including nucleic acids, proteins, metabolites, lipopolysaccharides, and peptidoglycans. Bacteria extracellular vesicles (BEVs) are promising lipid-bilayer nanocarriers for the treatment of many diseases due to their low toxicity, drug loading capacity, ease of modification and industrialization. Specially, BEVs-based cancer therapy has attracted much attention because of their ability to effectively stimulate immune responses. In this review, we provide an overview of the biogenesis, composition, isolation, classification, and internalization of BEVs. We then comprehensively summarize the sources of BEVs in cancer therapy and the BEVs-related cancer treatment strategies. We further highlight the great potential of BEVs in bone and soft tissue tumors. Finally, we conclude the major advantages and challenges of BEVs-based cancer therapy. We believe that the comprehensive understanding of BEVs in the field of cancer therapy will generate innovative solutions to bone and soft tissue tumors and achieve clinical applications.

Evaluation of the expression pattern and diagnostic value of PPARγ in malignant and benign primary bone tumors

PURPOSE

The quantifiable description of PPARγ expression pattern beside mechanistic in-vitro evidence will provide insights into the involvement of this mediator in tumor pathogenesis. This study is focused on illuminating the PPARγ gene and protein expression pattern, its association with tumor deterioration and its diagnostic value in different types of primary bone tumors.

METHODS

The expression pattern of PPARγ was investigated in the 180 bone tissues including 90 bone tumor tissues and 90 non-cancerous bone tissues. The local PPARγ expression level was assessed using real-time qRT-PCR and the PPARγ protein expression pattern was measured using immunohistochemistry. The correlation of PPARγ expression level with patients' clinic-pathological features, also the value of the variables in predicting PPARγ expression level in tumors and the value of PPARγ to discriminate tumor subtypes were assessed.

RESULTS

The mean PPARγ mRNA expression was significantly higher in bone tumors compared to healthy bone tissues, also the malignant tumors including osteosarcoma and Ewing sarcoma had the elevated level of PPARγ mRNA compared to GCT tumors. Consistently, the protein expression of PPARγ in the tumor site was significantly higher in the bone tumors and malignant tumors compared to non-cancerous and benign tumors, respectively. The PPARγ protein could predict malignant tumor features including tumor grade, metastasis and recurrence significantly. Moreover, PPARγ could potentially discriminate the patients from the controls also malignant tumors from benign tumors with significant sensitivity and specificity.

CONCLUSIONS

PPARγ might be involved in primary bone tumor pathogenesis and determining its molecular mechanism regarding bone cancer pathogenesis is of grave importance.

Expression pattern and clinical significance of β-catenin gene and protein in patients with primary malignant and benign bone tumors

This study is aimed to unravel the status of local and circulating β-catenin in different primary bone tumors and its relevance to tumor types, severity, and chemotherapy. The β-catenin mRNA expression level and the expression of the protein (intensity level) were evaluated in tumor tissue and peripheral blood mononuclear cells of 150 patients with different types of primary bone tumors (78 malignant and 72 benign tumors) using Real-Time PCR and immunohistochemistry. The β-catenin mRNA expression level and the expression of the protein were increased in bone tumors which was positively correlated with the tumor malignancy. Amongst osteosarcoma, Ewing's Sarcoma, chondrosarcoma, osteochondroma, Giant Cell Tumor, and exostosis tumors, the osteosarcoma, and Giant Cell Tumor groups showed the highest level of β-catenin expression. The β-catenin expression in malignant bone tumors was significantly correlated with tumor grade, size, metastasis, tumor recurrent, and the level of response to chemotherapy. A similar pattern of β-catenin gene expression and its association with tumor characteristics was detected in the patient's peripheral blood cells. The simultaneous increase in the expression of the β-catenin gene and protein in tumor tissue and in circulating blood cells and its relationship with tumor severity indicates the possible promoting role of β-catenin in primary bone tumor pathogenesis.

The EPH/Ephrin System in Bone and Soft Tissue Sarcomas' Pathogenesis and Therapy: New Advancements and a Literature Review

Musculoskeletal sarcomas represent rare heterogenous malignancies of mesenchymal origin that can be divided in two distinct subtypes, bone and soft tissue sarcomas. Current treatment options combine the surgical excision of local tumors and multidrug chemotherapy to prevent metastatic widespread disease. Due to the grim prognosis that usually accompanies such tumors, researchers have attempted to shed light on the molecular pathways implicated in their pathogenesis in order to develop novel, innovative, personalized therapeutic strategies. Erythropoietin-producing human hepatocellular receptors (EPHs) are tyrosine-kinase transmembrane receptors that, along with their ligands, ephrins, participate in both tumor-suppressive or tumor-promoting signaling pathways in bone and soft tissue sarcomas. The EPH/ephrin axis orchestrates cancerous processes such as cell–cell and cell–substrate adhesion and enhances the remodeling of the intracellular cytoskeleton to stimulate the motility and invasiveness of sarcoma cells. The purpose of our study was to review published PubMed literature to extract results from in vitro, in vivo and clinical trials indicative of the role of EPH/ephrin signaling in bone and soft tissue sarcomas. Based on these reports, significant interactions between the EPH/ephrin signaling pathway and a plethora of normal and abnormal cascades contribute to molecular mechanisms enhancing malignancy during sarcoma progression. In addition, EPHs and ephrins are prospective candidates for diagnostic, monitoring and therapeutic purposes in the clinical setting against bone and soft tissue sarcomas.

Pembrolizumab Achieves a Complete Response in an NF-1 Mutated, PD-L1 Positive Malignant Peripheral Nerve Sheath Tumor: A Case Report and Review of the Benchmarks

Malignant peripheral nerve sheath tumors (MPNSTs) represent a rare subtype of neural crest cell-derived soft tissue sarcomas (STS). Standard of care therapy comprises surgical resection followed by adjuvant radiation, and most clinical studies have demonstrated finite survival benefit of radiation and chemotherapy. In metastatic disease, palliative chemotherapy provides very limited efficacy. We report a 60-year-old male patient with a primary para vertebral tumor at T7-T8 with lung metastases who recurred after surgical resection and later progressed on epirubicin plus ifosfamide. He was an international patient and referred to the phase 1 clinic. Molecular profiling and immunohistochemistry of the tumor revealed a PD-L1 expression of 70% (2+) and pathogenic genetic alterations by next-generation sequencing in ARID1A, CDKN2A, KMT2A, NF1, and TP53. Immune checkpoint therapy (ICT) with pembrolizumab was commenced, and interval computed tomography revealed a complete remission by cycle 6. Randomized clinical trials illustrate that ICTs such as anti-PD-1 and anti-CTLA4 monoclonal antibodies in STS cohorts display low or modest response rates by variable PD-L1 expression. This and 3 other case reports of disparate PD-L1 expression demonstrate complete responses in PD-L1 positive MPNSTs treated with ICT. These case reports necessitate further study of ICT in neural crest cell subtype of STS.

PLOD Family: A Novel Biomarker for Prognosis and Personalized Treatment in Soft Tissue Sarcoma

Despite various treatment attempts, the heterogenous group of soft tissue sarcomata (STS) with more than 100 subtypes still shows poor outcomes. Therefore, effective biomarkers for prognosis prediction and personalized treatment are of high importance. The Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase (PLOD) gene family, which is related to multiple cancer entities, consists of three members which encode important enzymes for the formation of connective tissue. The relation to STS, however, has not yet been explored. In this study, data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases were used to analyze the role of PLOD1–3 in STS. It was found that an overexpression of PLOD family members correlates with poor prognosis, which might be due to an increased infiltration of immune-related cells in the tumor microenvironment. In STS, the expression of PLOD genes could be a novel biomarker for prognosis and a personalized, more aggressive treatment in these patients.

CDK7-dependent transcriptional addiction in bone and soft tissue sarcomas: Present and Future

Cancer arises from genetic alterations that invariably contribute to dysregulated transcriptional programs. These dysregulated programs establish and maintain specific cancer cell states, leading to an intensive dependence on a set of certain regulators of gene expression. The CDK7 functions as the core of transcription, and governs RNA polymerase II and the downstream oncogenes expression in cancers. CDK7 inhibition leads to reduced recruitment of super-enhancers-driven oncogenic transcription factors, and the depression of these associated oncogenes expression, which indicates the dependence of transcriptional addiction of cancers on CDK7. Given that specified oncoproteins of sarcomas commonly function at oncogenic transcription, targeting CDK7-denpendent transcriptional addiction may be of guiding significance for the treatment of sarcomas. In this review, we summarize the advances in mechanism of targeted CDK7-dependent transcriptional addiction and discuss the path ahead to potential application discovery in bone and soft tissue sarcomas, providing theoretical considerations for bio-orthogonal therapeutic strategies.

Sarcomas of the extremities and the pelvis: comparing local recurrence after incisional and after core-needle biopsy

BACKGROUND

The degree of contamination of healthy tissue with tumor cells during a biopsy in bone or soft tissue sarcomas is clearly dependant on the type of biopsy. Some studies have confirmed a clinically relevant contamination of the biopsy tract after incisional biopsies, as opposed to core-needle biopsies. The aim of our prospective study was to evaluate the risk of local recurrence depending on the biopsy type in extremity and pelvis sarcomas.

METHODS

We included 162 patients with a minimum follow-up of 6 months after wide resection of extremity sarcomas. All diagnostic and therapeutic procedures were performed at a single, dedicated sarcoma center. The excision of the biopsy tract after an incisional biopsy was performed as a standard with all tumor resections. All patients received their follow-up after the conclusion of therapy at our center by means of regional MRI studies and, at a minimum, CT of the thorax to rule out pulmonary metastatic disease. The aim of the study was the evaluation of the influence of the biopsy type and of several other clinical factors on the rate of local recurrence and on the time of local recurrence-free survival.

RESULTS

One hundred sixty-two patients with bone or soft tissue tumors of the extremities and the pelvis underwent either an incisional or a core-needle biopsy of their tumor, with 70 sarcomas (43.2%) being located in the bone. 84.6% of all biopsies were performed as core-needle biopsies. The median follow-up time was 55.6 months, and 22 patients (13.6%) developed a local recurrence after a median time of 22.4 months. There were no significant differences between incisional and core-needle biopsy regarding the risk of local recurrence in our subgroup analysis with differentiation by kind of tissue, grading of the sarcoma, and perioperative multimodal therapy.

CONCLUSIONS

In a large and homogenous cohort of extremity and pelvic sarcomas, we did not find significant differences between the groups of incisional and core-needle biopsy regarding the risk of local recurrence. The excision of the biopsy tract after incisional biopsy in the context of the definitive tumor resection seems to be the decisive factor for this result.

T-LAK cell-originated protein kinase (TOPK): an emerging prognostic biomarker and therapeutic target in osteosarcoma

T-lymphokine-activated killer (T-LAK) cell-originated protein kinase (TOPK) is an emerging target with critical roles in various cancers; however, its expression and function in osteosarcoma remain unexplored. We evaluated TOPK expression using RNA sequencing and gene expression data from public databases (TARGET-OS, CCLE, GTEx, and GENT2) and immunohistochemistry in an osteosarcoma tissue microarray (TMA). TOPK gene expression was significantly higher in osteosarcoma than normal tissues and directly correlated with shorter overall survival. TOPK was overexpressed in 83.3% of the osteosarcoma specimens within our TMA and all osteosarcoma cell lines, whereas normal osteoblast cells had no aberrant expression. High expression of TOPK associated with metastasis, disease status, and shorter overall survival. Silencing of TOPK with small interfering RNA (siRNA) decreased cell viability, and inhibition with the selective inhibitor OTS514 suppressed osteosarcoma cell proliferation, migration, colony-forming ability, and spheroid growth. Enhanced chemotherapeutic sensitivity and a synergistic effect were also observed with the combination of OTS514 and either doxorubicin or cisplatin in osteosarcoma cell lines. Taken together, our study demonstrated that TOPK is a potential prognostic biomarker and therapeutic target for osteosarcoma treatment.

The basic characteristics of extracellular vesicles and their potential application in bone sarcomas

Bone sarcomas are rare cancers accompanied by metastatic disease, mainly including osteosarcoma, Ewing sarcoma and chondrosarcoma. Extracellular vesicles (EVs) are membrane vesicles released by cells in the extracellular matrix, which carry important signal molecules, can stably and widely present in various body fluids, such as plasma, saliva and scalp fluid, spinal cord, breast milk, and urine liquid. EVs can transport almost all types of biologically active molecules (DNA, mRNA, microRNA (miRNA), proteins, metabolites, and even pharmacological compounds). In this review, we summarized the basic biological characteristics of EVs and focused on their application in bone sarcomas. EVs can be use as biomarker vehicles for diagnosis and prognosis in bone sarcomas. The role of EVs in bone sarcoma has been analyzed point-by-point. In the microenvironment of bone sarcoma, bone sarcoma cells, mesenchymal stem cells, immune cells, fibroblasts, osteoclasts, osteoblasts, and endothelial cells coexist and interact with each other. EVs play an important role in the communication between cells. Based on multiple functions in bone sarcoma, this review provides new ideas for the discovery of new therapeutic targets and new diagnostic analysis.

Osteosarcoma in Children: Not Only Chemotherapy

Osteosarcoma (OS) is the most severe bone malignant tumor, responsible for altered osteoid deposition and with a high rate of metastasis. It is characterized by heterogeneity, chemoresistance and its interaction with bone microenvironment. The 5-year survival rate is about 67% for patients with localized OS, while it remains at 20% in case of metastases. The standard therapy for OS patients is represented by neoadjuvant chemotherapy, surgical resection, and adjuvant chemotherapy. The most used chemotherapy regimen for children is the combination of high-dose methotrexate, doxorubicin, and cisplatin. Considered that the necessary administration of high-dose chemotherapy is responsible for a lot of acute and chronic side effects, the identification of novel therapeutic strategies to ameliorate OS outcome and the patients' life expectancy is necessary. In this review we provide an overview on new possible innovative therapeutic strategies in OS.

Development of a Novel Immune Infiltration-Related ceRNA Network and Prognostic Model for Sarcoma

Due to the rarity and heterogeneity, it is challenging to explore and develop new therapeutic targets for patients with sarcoma. Recently, immune cell infiltration in the tumor microenvironment (TME) was widely studied, which provided a novel potential approach for cancer treatment. The competing endogenous RNA (ceRNA) regulatory network has been reported as a critical molecular mechanism of tumor development. However, the role of the ceRNA regulatory network in the TME of sarcoma remains unclear. In this study, gene expression data and clinical information were obtained from The Cancer Genome Atlas (TCGA) sarcoma datasets, and an immune infiltration-related ceRNA network was constructed, which comprised 14 lncRNAs, 13 miRNAs, and 23 mRNAs. Afterward, we constructed an immune infiltration-related risk score model based on the expression of IRF1, MFNG, hsa-miR-940, and hsa-miR-378a-5p, presenting a promising performance in predicting the prognosis of patients with sarcoma.

Randomised phase 2 study comparing the efficacy and safety of the oral tyrosine kinase inhibitor nintedanib with single agent ifosfamide in patients with advanced, inoperable, metastatic soft tissue sarcoma after failure of first-line chemotherapy: EORTC-1506-STBSG "ANITA"

PURPOSE

EORTC-1506-STBSG was a prospective, multicentric, randomised, open-label phase 2 trial to assess the efficacy and safety of second-line nintedanib versus ifosfamide in patients with advanced, inoperable metastatic soft tissue sarcoma (STS). The primary end-point was progression-free survival.

PATIENTS/METHODS

Patients with a variety of STS subtypes were randomised 1:1 to nintedanib (200 mg b.i.d. p.o. until disease progression) or ifosfamide (3 g/m² i.v. days 1-3, every 21 days for ≤6 cycles). A Korn design was applied aiming to detect an improvement in median progression-free survival (mPFS) from 3 to 4.5 months (HR = 0.667). An interim look was incorporated to stop the trial for futility if <19 of the first 36 patients treated with nintedanib were progression-free at week 12.

RESULTS

At the interim analysis, among the first 36 eligible and evaluable patients randomised for nintedanib, only 13 (36%) were progression-free at week 12. The trial was closed for further accrual as per protocol. In total, 80 patients were randomised (40 per treatment group). The mPFS was 2.5 months (95% CI: 1.5-3.4) for nintedanib and 4.4 months (95% CI: 2.9-6.7) on ifosfamide (adjusted HR = 1.56 [80% CI: 1.14-2.13], p = 0.070). The median overall survival was 13.7 months (95% CI: 9.4-23.4) on nintedanib and 24.1 months (95% CI: 10.9-NE) on ifosfamide (adjusted HR = 1.65 [95%CI:0.89-3.06], p = 0.111). The clinical benefit rate for nintedanib and ifosfamide was 50% versus 62.5% (p = 0.368), respectively. Common treatment-related adverse events (all grades) were diarrhoea (35.9% of patients), fatigue (25.6%) and nausea (20.5%) for nintedanib; and fatigue (52.6%), nausea (44.7%) and vomiting, anorexia and alopecia (28.9% each) for ifosfamide.

CONCLUSION

The trial was stopped for futility. The activity of nintedanib did not warrant further exploration in non-selected, advanced STSs.

Anlotinib: A Novel Targeted Drug for Bone and Soft Tissue Sarcoma

Bone and soft tissue sarcomas account for approximately 15% of pediatric solid malignant tumors and 1% of adult solid malignant tumors. There are over 50 subtypes of sarcomas, each of which is notably heterogeneous and manifested by remarkable phenotypic and morphological variability. Anlotinib is a novel oral tyrosine kinase inhibitor (TKI) targeting c-kit, platelet-derived growth factor receptors, fibroblast growth factor receptor, and vascular endothelial growth factor receptor. In comparison with the placebo, anlotinib was associated with better overall survival and progression-free survival (PFS) in a phase III trial of patients with advanced non-small cell lung cancer (NSCLC), albeit with cancer progression after two previous lines of treatment. Recently, the National Medical Products Administration approved anlotinib monotherapy as a third-line treatment for patients with advanced NSCLC. Additionally, a phase IIB randomized trial substantiated that anlotinib is associated with a significant longer median PFS in patients with advanced soft tissue sarcoma. Moreover, anlotinib is also effective in patients with advanced medullary thyroid carcinoma and metastatic renal cell carcinoma. Anlotinib has similar tolerability to other TKIs targeting vascular endothelial growth factor receptors and other tyrosine kinase-mediated pathways. However, anlotinib has a notably lower rate of side effects ≥grade 3 relative to sunitinib. This review discussed the remarkable characteristics and major dilemmas of anlotinib as a targeted therapy for sarcomas.

Prognosis prediction of extremity and trunk wall soft-tissue sarcomas treated with surgical resection with radiomic analysis based on random survival forest

Many researches have applied machine learning methods to find associations between radiomic features and clinical outcomes. Random survival forests (RSF), as an accurate classifier, sort all candidate variables as the rank of importance values. There was no study concerning on finding radiomic predictors in patients with extremity and trunk wall soft-tissue sarcomas using RSF. This study aimed to determine associations between radiomic features and overall survival (OS) by RSF analysis. To identify radiomic features with important values by RSF analysis, construct predictive models for OS incorporating clinical characteristics, and evaluate models' performance with different method. We collected clinical characteristics and radiomic features extracted from plain and contrast-enhanced computed tomography (CT) from 353 patients with extremity and trunk wall soft-tissue sarcomas treated with surgical resection. All radiomic features were analyzed by Cox proportional hazard (CPH) and followed RSF analysis. The association between radiomics-predicted risks and OS was assessed by Kaplan-Meier analysis. All clinical features were screened by CPH analysis. Prognostic clinical and radiomic parameters were fitted into RSF and CPH integrative models for OS in the training cohort, respectively. The concordance indexes (C-index) and Brier scores of both two models were evaluated in both training and testing cohorts. The model with better predictive performance was interpreted with nomogram and calibration plots. Among all 86 radiomic features, there were three variables selected with high importance values. The RSF on these three features distinguished patients with high predicted risks from patients with low predicted risks for OS in the training set (P < 0.001) using Kaplan-Meier analysis. Age, lymph node involvement and grade were incorporated into the combined models for OS (P < 0.05). The C-indexes in both two integrative models fluctuated above 0.80 whose Brier scores maintained less than 15.0 in the training and testing datasets. The RSF model performed little advantages over the CPH model that the calibration curve of the RSF model showed favorable agreement between predicted and actual survival probabilities for the 3-year and 5-year survival prediction. The multimodality RSF model including clinical and radiomic characteristics conducted high capacity in prediction of OS which might assist individualized therapeutic regimens. Level III, prognostic study.

Anti-tumour drugs of marine origin currently at various stages of clinical trials (review)

Oncological diseases for a long time have remained one of the most significant health problems of modern society, which causes great losses in its labour and vital potential. Contemporary oncology still faces unsolved issues as insufficient efficacy of treatment of progressing and metastatic cancer, chemoresistance, and side-effects of the traditional therapy which lead to disabilities among or death of a high number of patients. Development of new anti-tumour preparations with a broad range of pharmaceutical properties and low toxicity is becoming increasingly relevant every year. The objective of the study was to provide a review of the recent data about anti-tumour preparations of marine origin currently being at various phases of clinical trials in order to present the biological value of marine organisms – producers of cytotoxic compounds, and the perspectives of their use in modern biomedical technologies. Unlike the synthetic oncological preparations, natural compounds are safer, have broader range of cytotoxic activity, can inhibit the processes of tumour development and metastasis, and at the same time have effects on several etiopathogenic links of carcinogenesis. Currently, practical oncology uses 12 anti-tumour preparations of marine origin (Fludarabine, Cytarabine, Midostaurin, Nelarabine, Eribulin mesylate, Brentuximab vedotin, Trabectedin, Plitidepsin, Enfortumab vedotin, Polatuzumab vedotin, Belantamab mafodotin, Lurbinectedin), 27 substances are at different stages of clinical trials. Contemporary approaches to the treatment of oncological diseases are based on targeted methods such as immune and genetic therapies, antibody-drug conjugates, nanoparticles of biopolymers, and metals. All those methods employ bioactive compounds of marine origin. Numerous literature data from recent years indicate heightened attention to the marine pharmacology and the high potential of marine organisms for the biomedicinal and pharmaceutic industries.

Integrated analysis of lncRNA-miRNA-mRNA ceRNA network and the potential prognosis indicators in sarcomas

BACKGROUND

Competitive endogenous RNA (ceRNA) networks have revealed a new mechanism of interaction between RNAs, and play crucial roles in multiple biological processes and development of neoplasms. They might serve as diagnostic and prognosis markers as well as therapeutic targets.

METHODS

In this work, we identified differentially expressed mRNAs (DEGs), lncRNAs (DELs) and miRNAs (DEMs) in sarcomas by comparing the gene expression profiles between sarcoma and normal muscle samples in Gene Expression Omnibus (GEO) datasets. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses were applied to investigate the primary functions of the overlapped DEGs. Then, lncRNA-miRNA and miRNA-mRNA interactions were predicted, and the ceRNA regulatory network was constructed using Cytoscape software. In addition, the protein-protein interaction (PPI) network and survival analysis were performed.

RESULTS

A total of 1296 DEGs were identified in sarcoma samples by combining the GO and KEGG enrichment analyses, 338 DELs were discovered after the probes were reannotated, and 36 DEMs were ascertained through intersecting two different expression miRNAs sets. Further, through target gene prediction, a lncRNA-miRNA-mRNA ceRNA network that contained 113 mRNAs, 69 lncRNAs and 29 miRNAs was constructed. The PPI network identified the six most significant hub proteins. Survival analysis revealed that seven mRNAs, four miRNAs and one lncRNA were associated with overall survival of sarcoma patients.

CONCLUSIONS

Overall, we constructed a ceRNA network in sarcomas, which might provide insights for further research on the molecular mechanism and potential prognosis biomarkers.

Identification of prognostic biomarkers associated with metastasis and immune infiltration in osteosarcoma

Osteosarcoma is the most common primary malignancy of the bones, and is associated with a high rate of metastasis and a poor prognosis. A tight association between the tumor microenvironment (TME) and osteosarcoma metastasis has been established. In the present study, the Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) algorithm was applied to calculate the immune and stromal scores of patients with osteosarcoma based on data from The Cancer Genome Atlas database. A metagene approach and deconvolution method were used to reveal distinct TME landscapes in patients with osteosarcoma. Bioinformatics analysis was used to identify differentially expressed genes (DEGs) associated with metastasis and immune infiltration in osteosarcoma, and a risk model was constructed using the DEGs with potential prognostic significance. Subsequently, gene set enrichment and Spearman's correlation analyses were used to delineate the biological processes associated with these prognostic biomarkers. Finally, immunohistochemical (IHC) analysis was performed to evaluate the expression levels of immune infiltrates and prognostic biomarkers in clinical osteosarcoma tissues. The results of the ESTIMATE demonstrated that patients with non-metastatic osteosarcoma presented with higher immune/stromal scores and a more favorable prognosis compared with those with metastatic osteosarcoma. The TME landscapes in patients with osteosarcoma suggested that high levels of tumor-infiltrating immune cells (TIICs) may suppress metastasis. Increased numbers of CD56bright natural killer cells, immature B cells, M1 macrophages and neutrophils, and lower levels of M2 macrophages were observed in the non-metastatic tissues compared with those in the metastatic tissues. A total of 69 DEGs were identified to be associated with metastasis and immune infiltration in osteosarcoma. Of these, GATA3, LPAR5, EVI2B, RIAM and CFH exhibited prognostic potential and were highly expressed in non-metastatic osteosarcoma tissues based on the IHC analysis results. These biomarkers were involved in various immune-related biological processes and were positively associated with multiple TIICs and immune signatures. The risk model constructed using these prognostic biomarkers demonstrated high predictive accuracy for the prognosis of osteosarcoma. In conclusion, the present study proposed a five-biomarker prognostic signature for the prediction of metastasis and immune infiltration in patients with osteosarcoma.

Combination Methionine-methylation-axis Blockade: A Novel Approach to Target the Methionine Addiction of Cancer

BACKGROUND/AIM

Cancers are selectively sensitive to methionine (MET) restriction (MR) due to their addiction to MET which is overused for elevated methylation reactions. MET addiction of cancer was discovered by us 45 years ago. MR of cancer results in depletion of S-adenosylmethionine (SAM) for transmethylation reactions, resulting in selective cancer-growth arrest in the late S/G₂-phase of the cell cycle. The aim of the present study was to determine if blockade of the MET-methylation axis is a highly-effective strategy for cancer chemotherapy.

MATERIALS AND METHODS

In the present study, we demonstrated the efficacy of MET-methylation-axis blockade using MR by oral-recombinant methioninase (o-rMETase) combined with decitabine (DAC), an inhibitor of DNA methylation, and an inhibitor of SAM synthesis, cycloleucine (CL). We determined a proof-of-concept of the efficacy of the MET-methylation-axis blockade on a recalcitrant undifferentiated/unclassified soft-tissue sarcoma (USTS) patient-derived orthotopic xenograft (PDOX) mouse model.

RESULTS

The o-rMETase-CL-DAC combination regressed the USTS PDOX with extensive cancer necrosis.

CONCLUSION

The new concept of combination MET-methylation-axis blockade is effective and can now be tested on many types of recalcitrant cancer.

miR-140 inhibits osteosarcoma progression by impairing USP22-mediated LSD1 stabilization and promoting p21 expression

Osteosarcoma is a bone tumor frequently diagnosed in children and young adults. Despite advances in chemotherapy and surgical resection, tumors metastasize in 30% of osteosarcoma patients. In addition, side effects caused by chemotherapeutic drugs, as well as the development of chemoresistance, highlight the need to identify the molecular mechanisms involved in the pathogenesis of osteosarcoma. We compared 65 osteosarcoma samples to their adjacent normal tissues, as well as commercially obtained osteosarcoma cell lines with normal osteoblast cell lines, and identified a role for the microRNA (miR)-140/ubiquitin-specific protease 22 (USP22)/lysine-specific demethylase 1 (LSD1)/p21 axis in the development of osteosarcoma. Osteosarcoma tissues and cells exhibited poor miR-140 and p21 expression, whereas the expression of USP22 and LSD1 was increased. Overexpression of miR-140 inhibited cell proliferation, migration, and invasion and promoted cell apoptosis by directly targeting USP22, resulting in its decreased expression. Overexpression of USP22 reversed the effects of miR-140 overexpression in osteosarcoma cells. Overexpression of miR-140 or USP22 knockdown led to the ubiquitination and degradation of LSD1. miR-140 overexpression also suppressed tumorigenesis in vivo. This study revealed a role for miR-140 in the restriction of osteosarcoma development and identified miR-140 as a potential target for therapeutic intervention.

Real-Time Fluorescence Image-Guided Oncolytic Virotherapy for Precise Cancer Treatment

Oncolytic virotherapy is one of the most promising, emerging cancer therapeutics. We generated three types of telomerase-specific replication-competent oncolytic adenovirus: OBP-301; a green fluorescent protein (GFP)-expressing adenovirus, OBP-401; and Killer-Red-armed OBP-301. These oncolytic adenoviruses are driven by the human telomerase reverse transcriptase (hTERT) promoter; therefore, they conditionally replicate preferentially in cancer cells. Fluorescence imaging enables visualization of invasion and metastasis in vivo at the subcellular level; including molecular dynamics of cancer cells, resulting in greater precision therapy. In the present review, we focused on fluorescence imaging applications to develop precision targeting for oncolytic virotherapy. Cell-cycle imaging with the fluorescence ubiquitination cell cycle indicator (FUCCI) demonstrated that combination therapy of an oncolytic adenovirus and a cytotoxic agent could precisely target quiescent, chemoresistant cancer stem cells (CSCs) based on decoying the cancer cells to cycle to S-phase by viral treatment, thereby rendering them chemosensitive. Non-invasive fluorescence imaging demonstrated that complete tumor resection with a precise margin, preservation of function, and prevention of distant metastasis, was achieved with fluorescence-guided surgery (FGS) with a GFP-reporter adenovirus. A combination of fluorescence imaging and laser ablation using a KillerRed-protein reporter adenovirus resulted in effective photodynamic cancer therapy (PDT). Thus, imaging technology and the designer oncolytic adenoviruses may have clinical potential for precise cancer targeting by indicating the optimal time for administering therapeutic agents; accurate surgical guidance for complete resection of tumors; and precise targeted cancer-specific photosensitization.

Microvascular Density, Endothelial Area, and Ki-67 Proliferative Index Correlate Each Other in Cat Post-Injection Fibrosarcoma

Soft tissue sarcomas are a large group of different tumor types both in humans and in animals. Among them, fibrosarcoma is the most frequent malignant mesenchymal tumoral form in cats, representing up to 28% of all cat skin tumors, while human fibrosarcoma, fortunately, only represents 5% of all sarcomas and 0.025% of the world-wide burden of tumors. This low incidence in humans leads to consideration of this group of tumoral diseases as rare, so therapeutic options are few due to the difficulty of starting clinical trials. In this context, the identification of research models for fibrosarcomas could be of great interest to deepen knowledge in this field and recognize new or possible biological pathways involved in tumor progression and metastasis. Angiogenesis is considered a fundamental scattering cause of tumor aggressiveness and progression in all forms of cancer, but only a few research parameters were developed and reported to express them quantitatively and qualitatively. The role in angiogenesis of microenvironmental stromal cells, such as fibroblasts, lymphocytes, mast cells, and macrophages, was largely demonstrated since this topic was first approached, while quantification of new vessels and their blood capacity in tumoral area is a relatively recent approach that could be well developed thanks to expertise in immunohistochemistry and image analysis. In this paper, a crossing study evaluating microvascular density (MVD), endothelial area (EA), and Ki-67 proliferative index was reported for a series of formalin-fixed and paraffin-embedded tissue samples from 99 cat patients, affected by cat post-injection fibrosarcoma, by using a till ×400 magnification light microscopy. We aim to demonstrate that cat pets may be considered a useful animal model for better studying the correspondent human diseases and we report, for the first time to our knowledge, experimental data in terms of correlation among MVD, EA, and Ki-67 strictly involved in aggressiveness and tumoral progression.

Selection of Effective Therapies Using Three-Dimensional in vitro Modeling of Chondrosarcoma

Purpose: Chondrosarcomas are a group of cartilaginous malignant neoplasms characterized by the deposition of chondrogenic extracellular matrix. Surgical resection is currently the only curative treatment option, due to their high resistance to conventional chemotherapy and radiotherapy. Novel therapeutic treatment options may improve outcome. Predominantly used cell line monolayer in vitro models lack in vivo complexity, such as the presence of extracellular matrix, and differing oxygen access. Hence, we aimed to improve pre-clinical chondrosarcoma research by developing an alginate-based 3D cell culture model.

Method: An alginate scaffold was applied to generate spheroids of three chondrosarcoma cell lines (CH2879, JJ012, SW1353). Morphological, histological and immunohistochemical assessment of the spheroids were used to characterize the chondrosarcoma model. Presto blue assay, morphological and immunohistochemical assessment were applied to assess spheroid response to a panel of chemotherapeutics and targeted therapies, which was compared to conventional 2D monolayer models. Synergistic effect of doxorubicin and ABT-737 (Bcl-2 inhibitor) was compared between monolayer and spheroid models using excess over Bliss. A 3D colony formation assay was developed for assessment of radiotherapy response.

Results: Chondrosarcoma spheroids produced chondrogenic matrix and remained proliferative after 2 weeks of culture. When treated with chemotherapeutics, the spheroids were more resistant than their monolayer counterparts, in line with animal models and clinical data. Moreover, for sapanisertib (mTOR inhibitor) treatment, a recovery in chondrosarcoma growth, previously observed in mice models, was also observed using long-term treatment. Morphological assessment was useful in the case of YM-155 (survivin inhibitor) treatment where a fraction of the spheroids underwent cell death, however a large fraction remained proliferative and unaffected. Synergy was less pronounced in 3D compared to 2D. A 3D clonogenic assay confirmed increased resistance to radiotherapy in 3D chondrosarcoma spheroids.

Conclusion: We demonstrate that the chondrosarcoma alginate spheroid model is more representative of chondrosarcoma in vivo and should be used instead of the monolayer model for therapy testing. Improved selection at in vitro stage of therapeutic testing will increase the amount of information available for experimental design of in vivo animal testing and later, clinical stages. This can potentially lead to increased likelihood of approval and success at clinical trials.

Will Next-Generation Immunotherapy Overcome the Intrinsic Diversity and Low Immunogenicity of Sarcomas to Improve Clinical Benefit?

Sarcomas are a rare type of a heterogeneous group of tumours arising from mesenchymal cells that form connective tissues. Surgery is the most common treatment for these tumours, but additional neoadjuvant or adjuvant chemotherapy or radiation therapies may be necessary. Unfortunately, a significant proportion of patients treated with conventional therapies will develop metastatic disease that is resistant to therapies. Currently, there is an urgent need to develop more effective and durable therapies for the treatment of sarcomas. In recent years immunotherapies have revolutionised the treatment of a variety of cancers by restoring patient anti-tumour immune responses or through the adoptive infusion of immune effectors able to kill and eliminate malignant cells. The clinicopathologic and genetic heterogeneity of sarcomas, together with the generally low burden of somatic mutations potentially generating neoantigens, are currently limited to broad application of immunotherapy for patients with sarcomas. Nevertheless, a better understanding of the microenvironmental factors hampering the efficacy of immunotherapy and the identification of new and suitable therapeutic targets may help to overcome current limitations. Moreover, the recent advances in the development of immunotherapies based on the direct exploitation or targeting of T cells and/or NK cells may offer new opportunities to improve the treatment of sarcomas, particularly those showing recurrence or resistance to standard of care treatments.

Development of a novel immune-related genes prognostic signature for osteosarcoma

Immune-related genes (IRGs) are responsible for osteosarcoma (OS) initiation and development. We aimed to develop an optimal IRGs-based signature to assess of OS prognosis. Sample gene expression profiles and clinical information were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Genotype-Tissue Expression (GTEx) databases. IRGs were obtained from the ImmPort database. R software was used to screen differentially expressed IRGs (DEIRGs) and functional correlation analysis. DEIRGs were analyzed by univariate Cox regression and iterative LASSO Cox regression analysis to develop an optimal prognostic signature, and the signature was further verified by independent cohort (GSE39055) and clinical correlation analysis. The analyses yielded 604 DEIRGs and 10 hub IRGs. A prognostic signature consisting of 13 IRGs was constructed, which strikingly correlated with OS overall survival and distant metastasis (p < 0.05, p < 0.01), and clinical subgroup showed that the signature's prognostic ability was independent of clinicopathological factors. Univariate and multivariate Cox regression analyses also supported its prognostic value. In conclusion, we developed an IRGs signature that is a prognostic indicator in OS patients, and the signature might serve as potential prognostic indicator to identify outcome of OS and facilitate personalized management of the high-risk patients.

The local and circulating SOX9 as a potential biomarker for the diagnosis of primary bone cancer

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The SOX9 expression increased in tumor tissues and peripheral blood of malignant and benign bone tumors.

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The protein level of SOX9 is enhanced in malignant bone tumor tissues.

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SOX9 over-expression correlated with tumor severity, grade, invasion feature, poor response to therapy, and recurrence.

Purpose

The status of the local and circulating SOX9, a master regulator of the tumor fate, and its relevance to tumor types, severity, invasion feature, response to therapy, and chemotherapy treatment were surveyed in bone cancer in the current study.

Methods

The SOX9 expression level was evaluated in tissue and peripheral blood mononuclear cells from patients with different types of malignant and benign bone tumors also tumor margin tissues using Real-Time PCR. The protein level of SOX9 was assessed using immunohistochemistry and western blot analysis. Also, the correlations of the SOX9 expression level with the patient’s clinical and pathological features were considered.

Results

The remarkable overexpression of SOX9 was detected in bone tumors compared to tumor margin tissues (P < 0.0001). Malignant bone tumors revealed a higher expression of SOX9 compared to benign tumors (P < 0.0001) while osteosarcoma tumors showed higher expression levels compared to Ewing sarcoma, and chondrosarcoma. Overexpression of SOX9 was observed in high grade, metastatic, recurrent tumors also tumors with poor response to therapy. Besides, the patients under the chemotherapy treatment demonstrated higher levels of SOX9 compared to the rest of malignant tumors (P = 0.02). The simultaneous up-regulation of circulating SOX9 in the patients with bone cancer was observed compared to healthy individuals (P < 0.0001) accompanying with overexpression of SOX9 in malignant tumors compared to benign tumors (P < 0.0001). The circulating SOX9 expression was up-regulated in the patients with malignant bone tumors who receive chemotherapy treatment also patients with high grade, metastatic, recurrent tumors. The protein level of SOX9 was in line with our data on the SOX9 gene expression.

Conclusion

The simultaneous overexpression of local and circulating SOX9 in bone cancer besides its positive correlation with tumor severity, malignancy, size, and chemotherapy may deserve receiving more attention in bone cancer diagnosis and therapy.

Calcium-Dependent Calpain Activation-Mediated Mitochondrial Dysfunction and Oxidative Stress Are Required for Cytotoxicity of Epinecidin-1 in Human Synovial Sarcoma SW982 Cells

Synovial sarcoma is a rare but highly malignant and metastatic disease. Despite its relative sensitivity to chemotherapies, the high recurrence and low 5-year survival rate for this disease suggest that new effective therapeutic agents are urgently needed. Marine antimicrobial peptide epinecidin-1 (epi-1), which was identified from orange-spotted grouper (Epinephelus coioides), exhibits multiple biological effects, including bactericidal, immunomodulatory, and anticancer activities. However, the cytotoxic effects and mechanisms of epi-1 on human synovial sarcoma cells are still unclear. In this study, we report that epi-1 exhibits prominent antisynovial sarcoma activity in vitro and in a human SW982 synovial sarcoma xenograft model. Furthermore, we determined that calcium overload-induced calpain activation and subsequent oxidative stress and mitochondrial dysfunction are required for epi-1-mediated cytotoxicity. Interestingly, reactive oxygen species (ROS)-mediated activation of extracellular signal-regulated kinase (ERK) plays a protective role against epi-1-induced cytotoxicity. Our results provide insight into the molecular mechanisms underlying epi-1-induced cell death in human SW982 cells.

Bone and Soft-Tissue Sarcoma: A New Target for Telomerase-Specific Oncolytic Virotherapy

Adenovirus serotype 5 (Ad5) is widely and frequently used as a virus vector in cancer gene therapy and oncolytic virotherapy. Oncolytic virotherapy is a novel antitumor treatment for inducing lytic cell death in tumor cells without affecting normal cells. Based on the Ad5 genome, we have generated three types of telomerase-specific replication-competent oncolytic adenoviruses: OBP-301 (Telomelysin), green fluorescent protein (GFP)-expressing OBP-401 (TelomeScan), and tumor suppressor p53-armed OBP-702. These viruses drive the expression of the adenoviral E1A and E1B genes under the control of the hTERT (human telomerase reverse transcriptase-encoding gene) promoter, providing tumor-specific virus replication. This review focuses on the therapeutic potential of three hTERT promoter-driven oncolytic adenoviruses against bone and soft-tissue sarcoma cells with telomerase activity. OBP-301 induces the antitumor effect in monotherapy or combination therapy with chemotherapeutic drugs via induction of autophagy and apoptosis. OBP-401 enables visualization of sarcoma cells within normal tissues by serving as a tumor-specific labeling reagent for fluorescence-guided surgery via induction of GFP expression. OBP-702 exhibits a profound antitumor effect in OBP-301-resistant sarcoma cells via activation of the p53 signaling pathway. Taken together, telomerase-specific oncolytic adenoviruses are promising antitumor reagents that are expected to provide novel therapeutic options for the treatment of bone and soft-tissue sarcomas.

hsa_circ0021347 as a Potential Target Regulated by B7-H3 in Modulating the Malignant Characteristics of Osteosarcoma

In our previous study, we showed that B7-H3 played crucial roles in osteosarcoma (OS) development and might serve as a negative regulator of in osteoimmunology and help tumor cells escape immune surveillance. However, little is known about B7-H3 deficiency and its corresponding circRNA alteration or their relationship with osteosarcoma progression. Therefore, we established stable silencing of B7-H3 in OS cells and validated our results with western blotting and real-time PCR detection. Then, we performed a circRNA array to analyze the differential expression of circRNAs between the control and B7-H3 knockdown cells. The association between target circRNA expression and the clinicopathological features of patients with OS was further analyzed. As a result, hsa_circ0021347 was selected and validated to be significantly downregulated in OS tissues and cell lines and showed a strong negative relationship with B7-H3 expression in OS. In addition, clinicopathological features showed that hsa_circ0021347 in OS tissues was negatively associated with Enneking stage and positively associated with patients' survival. Finally, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and PANTHER pathway analyses were performed to predict a network of hsa_circ0021347/miRNAs interactions to help us develop potential biomarkers for clinical diagnosis and design therapeutic strategies for OS.

Combination of oral recombinant methioninase and decitabine arrests a chemotherapy-resistant undifferentiated soft-tissue sarcoma patient-derived orthotopic xenograft mouse model

Cancer cells are methionine (MET) and methylation addicted and are highly sensitive to MET restriction. The present study determined the efficacy of oral-recombinant methioninase (o-rMETase) and the DNA methylation inhibitor, decitabine (DAC) on restricting MET in an undifferentiated-soft tissue sarcoma (USTS) patient-derived orthotopic xenograft (PDOX) nude-mouse model. The USTS PDOX models were randomized into five treatment groups of six mice: Control; doxorubicin (DOX) alone; DAC alone; o-rMETase alone; and o-rMETase-DAC combination. Tumor size and body weight were measured during the 14 days of treatment. Tumor growth was arrested only in the o-rMETase-DAC condition. Tumors treated with the o-rMETase-DAC combination exhibited tumor necrosis with degenerative changes. This study demonstrates that the o-rMETase-DAC combination could arrest the USTS PDOX tumor suggesting clinical promise.

Undifferentiated Pleomorphic Sarcoma of the Hand with Lung Metastases

Undifferentiated pleomorphic sarcoma (UPS) is a rare tumor of mesenchymal origin affecting the hand in less than 3% of cases. A 92-year-old male reported an enlarging, painless mass on his left hand of three months duration. Examination of the hand revealed a soft, non-tender, immobile mass over the wrist joint, just proximal to his thumb. Immunohistochemistry findings on ultrasound-guided biopsy were consistent with UPS. Further intractable pain, ulceration, and bleeding necessitated urgent radiotherapy, which provided no relief. This was followed by amputation above the elbow. Seven months later, the patient presented with confusion. A chest X-ray revealed extensive bilateral pulmonary metastases. In light of this result, the patient was referred to the palliative care team. UPS carries a poor prognosis, with a high risk of metastases. Early diagnosis and treatment is required for optimal clinical outcomes. Through this case, we highlight the need for a more effective treatment strategy to improve clinical outcomes.

An update on emerging drugs in osteosarcoma: towards tailored therapies?

Introduction: Current treatment of conventional and non-conventional high-grade osteosarcoma (HGOS) is based on the surgical removal of primary tumor and, when possible, of metastases and local reccurrence, together with systemic pre- and post-operative chemotherapy with drugs that have been used since decades. Areas covered: This review is intended to summarize the new agents and therapeutic strategies that are under clinical evaluation in HGOS, with the aim to increase the cure probability of this highly malignant bone tumor, which has not significantly improved during the last 30-40 years. The list of drugs, compounds and treatment modalities presented and discussed here has been generated by considering only those that are included in presently ongoing and recruiting clinical trials, or which have been completed in the last 2 years with reported results, on the basis of the information obtained from different and continuously updated databases. Expert opinion: Despite HGOS is a rare tumor, several clinical trials are presently evaluating different treatment strategies, which may hopefully positively impact on the outcome of patients who experience unfavorable prognosis when treated with conventional therapies.