• genomics
• metabolomics
• multi‑omics
• osteosarcoma
• proteomics
• single‑cell sequencing
• transcriptomics

• Humans
• Osteosarcoma/genetics
• Osteosarcoma/therapy
• Osteosarcoma/metabolism
• Osteosarcoma/pathology
• Precision Medicine/methods
• Bone Neoplasms/genetics
• Bone Neoplasms/metabolism
• Bone Neoplasms/therapy
• Genomics/methods
• Metabolomics/methods
• Proteomics/methods
• Biomarkers, Tumor/genetics
• Transcriptome
• Multiomics

• bone regeneration
• immunomodulation
• mesenchymal stem/stromal stem cells
• osteosarcoma
• tumor microenvironment

• R21 AR080388 NIAMS NIH HHS

• Metastasis
• Osteosarcoma
• Tumor associated macrophage
• Tumor immunotherapy
• Tumor microenvironment

Mesenchymal stem stromal cells (MSC) are characterized by the intriguing capacity to home toward cancer cells after systemic administration. Thus, MSC can be harnessed as targeted delivery vehicles of cytotoxic agents against tumors. In cancer patients, MSC based advanced cellular therapies were shown to be safe but their clinical efficacy was limited. Indeed, the amount of systemically infused MSC actually homing to human cancer masses is insufficient to reduce tumor growth. Moreover, induction of an unequivocal anticancer cytotoxic phenotype in expanded MSC is necessary to achieve significant therapeutic efficacy. Ex vivo cell modifications are, thus, required to improve anti-cancer properties of MSC. MSC based cellular therapy products must be handled in compliance with good manufacturing practice (GMP) guidelines. In the present review we include MSC-improving manipulation approaches that, even though actually tested at preclinical level, could be compatible with GMP guidelines. In particular, we describe possible approaches to improve MSC homing on cancer, including genetic engineering, membrane modification and cytokine priming. Similarly, we discuss appropriate modalities aimed at inducing a marked cytotoxic phenotype in expanded MSC by direct chemotherapeutic drug loading or by genetic methods. In conclusion, we suggest that, to configure MSC as a powerful weapon against cancer, combinations of clinical grade compatible modification protocols that are currently selected, should be introduced in the final product. Highly standardized cancer clinical trials are required to test the efficacy of ameliorated MSC based cell therapies.

• Cancer
• Mesenchymal stem stromal cells
• Good manufacturing practice
• Homing
• Targeted therapy
• Ex vivo cell modification

It is the hope of clinicians and patients alike that stem cell-based therapeutic products will increasingly become applicable remedies for many diseases and injuries. Whereas some multipotent stem cells are already routinely used in regenerative medicine, the efficacious and safe clinical translation of pluripotent stem cells is still hampered by their inherent immunogenicity and tumorigenicity. In addition, stem cells harbor the paracrine potential to affect the behavior of cells in their microenvironment. On the one hand, this property can mediate advantageous supportive effects on the overall therapeutic concept. However, in the last years, it became evident that both, multipotent and pluripotent stem cells, are capable of inducing adjacent cells to become motile. Not only in the context of tumor development but generally, deregulated mobilization and uncontrolled navigation of patient’s cells can have deleterious consequences for the therapeutic outcome. A more comprehensive understanding of this ubiquitous stem cell feature could allow its proper clinical handling and could thereby constitute an important building block for the further development of safe therapies.

• Cell Movement
• Humans
• Multipotent Stem Cells
• Pluripotent Stem Cells/metabolism
• Regenerative Medicine
• Stem Cell Transplantation

• MHA/Coll scaffold
• Osteosarcoma
• biomimetic
• bone regeneration
• chemotherapy
• osteogenesis

Osteosarcoma is the most common primary bone malignancy in adolescents. Its high propensity to metastasize is the leading cause for treatment failure and poor prognosis. Although the research of osteosarcoma has greatly expanded in the past decades, the knowledge and new therapy strategies targeting metastatic progression remain sparse. The prognosis of patients with metastasis is still unsatisfactory. There is resonating urgency for a thorough and deeper understanding of molecular mechanisms underlying osteosarcoma to develop innovative therapies targeting metastasis. Toward the goal of elaborating the characteristics and biological behavior of metastatic osteosarcoma, it is essential to combine the diverse investigations that are performed at molecular, cellular, and animal levels from basic research to clinical translation spanning chemical, physical sciences, and biology. This review focuses on the metastatic process, regulatory networks involving key molecules and signaling pathways, the role of microenvironment, osteoclast, angiogenesis, metabolism, immunity, and noncoding RNAs in osteosarcoma metastasis. The aim of this review is to provide an overview of current research advances, with the hope to discovery druggable targets and promising therapy strategies for osteosarcoma metastasis and thus to overcome this clinical impasse.

• metabolism
• metastasis
• microenvironment
• noncoding RNAs
• osteosarcoma

Osteosarcoma (OS), a primary malignant bone tumor, stems from bone marrow-derived mesenchymal stem cells (BMSCs) and/or committed osteoblast precursors. Distant metastases, in particular pulmonary and skeletal metastases, are common in patients with OS. Moreover, extensive resection of the primary tumor and bone metastases usually leads to bone defects in these patients. Bone morphogenic protein-2 (BMP-2) has been widely applied in bone regeneration with the rationale that BMP-2 promotes osteoblastic differentiation of BMSCs. Thus, BMP-2 might be useful after OS resection to repair bone defects. However, the potential tumorigenicity of BMP-2 remains a concern that has impeded the administration of BMP-2 in patients with OS and in populations susceptible to OS with severe bone deficiency (e.g., in patients with genetic mutation diseases and aberrant activities of bone metabolism). In fact, some studies have drawn the opposite conclusion about the effect of BMP-2 on OS progression. Given the roles of BMSCs in the origination of OS and osteogenesis, we hypothesized that the responses of BMSCs to BMP-2 in the tumor milieu may be responsible for OS development. This review focuses on the relationship among BMSCs, BMP-2, and OS cells; a better understanding of this relationship may elucidate the accurate mechanisms of actions of BMP-2 in osteosarcomagenesis and thereby pave the way for clinically safer and broader administration of BMP-2 in the future. For example, a low dosage of and a slow-release delivery strategy for BMP-2 are potential topics for exploration to treat OS.

• bone morphogenetic protein-2
• bone-marrow-derived mesenchymal stem cell
• mesenchymal stem cells
• osteogenesis
• osteogenic differentiation
• osteosarcoma
• tumor heterogeneity

• extracellular vesicles
• mesenchymal stem cells
• osteosarcoma
• therapy

• Bone Neoplasms/pathology
• Bone Neoplasms/therapy
• Cancer-Associated Fibroblasts/cytology
• Cancer-Associated Fibroblasts/metabolism
• Cell Communication
• Extracellular Vesicles/metabolism
• Extracellular Vesicles/transplantation
• Humans
• Mesenchymal Stem Cells/cytology
• Mesenchymal Stem Cells/metabolism
• MicroRNAs/metabolism
• Neoplasm Metastasis
• Osteosarcoma/pathology
• Osteosarcoma/therapy
• Tumor Microenvironment

• VTR 2021 232 Helsinki University Hospital

• bone marrow
• macrophages
• mesenchymal stem cells
• osteoclasts
• osteosarcoma
• tumor microenvironment

• ACE-2
• AIDS
• COVID-19
• HIV
• SARS-CoV-2
• remdesivir

• BMSCs
• JAK2/STAT3 pathway
• exosomal LCP1
• miR-135a-5p
• osteosarcoma

• cancer-stem cells
• mesenchymal stem cells
• metastasis
• osteosarcomas (OSs)
• therapy
• tumor microenvironment
• tumor-associated macrophages (TAMs)

• Bone Neoplasms/immunology
• Bone Neoplasms/metabolism
• Bone Neoplasms/pathology
• Bone Neoplasms/therapy
• Humans
• Neoplasm Metastasis
• Osteosarcoma/immunology
• Osteosarcoma/metabolism
• Osteosarcoma/pathology
• Osteosarcoma/therapy
• Signal Transduction/immunology
• Tumor Microenvironment/immunology
• Tumor-Associated Macrophages/immunology
• Tumor-Associated Macrophages/metabolism
• Tumor-Associated Macrophages/pathology

Osteosarcomas (OS) is one the most common primary bone malignancy in humans with the lungs metastasis in most cases. Metastasis and recurrence of OS is attributed to cancer stem cells (CSCs). Our study aimed to evaluate the clinical significance of CD133 and C-X-C chemokine receptor type 4 (CXCR4) as the frequently applied markers for CSCs in OS patients.

In this cross-sectional, a total of 50 tissue samples from the patients with primary OS were immunohistochemically examined to detect the expression of CD133 and CXCR4. The associations of the relative expression and clinical significance of each marker were also evaluated.

High level expression of CD133 was detected in 26% of OS patient tissues. Of the 12 patients who showed lung metastasis, 5 cases showed high expression of CD133 with marginal trend correlation (P=0.06). No significant correlation was observed between CD133 expression and clinicopathological factors. Only 36% of cases showed CXCR4 expression which was not significantly correlated with gender, age, tumor size, necrosis, stage and metastasis (P>0.05). Clinically, patients with concomitant CD133/CXCR4 expression had significant association with lung metastasis (P=0.05).

Our findings showed that concomitant expression of CSC markers CD133/CXCR4 might had a synergistic effect on the OS poor prognosis. These markers could be considered as potential therapeutic candidates of OS targeted therapy.

• CD133
• CXCR4
• Prognosis
• bone cancer
• osteosarcoma

Background: The transfusion of blood that has been stored for some time was found to be associated with transfusion-related immune modulation (TRIM) responses in cancer patients, which could result in poor clinical outcomes, such as tumor recurrence, metastasis and reduced survival rate. Given the prior observation of the positive correlation between ubiquitin content in whole blood and storage duration by the investigators of the present study, it was hypothesized that this could be the causal link behind the association between the transfusion of stored blood and poor cancer prognosis.

Methods: In the present study, a melanoma mouse model was used to study the potential clinical impact of ubiquitin present in stored blood on cancer prognosis through a variety of cell biology methods, such as flow cytometry and immunohistochemistry.

Results: Both extracellular ubiquitin and the infusion of stored mice blood that comprised of ubiquitin reduced the apoptotic rate of melanoma cells, promoted lung tumor metastasis and tumor progression, and reduced the long-term survival rate of melanoma mice. In addition, the upregulation of tumor markers and tumorigenic TH2 cytokine generation, as well as reduced immune cell numbers, were observed in the presence of ubiquitin.

Conclusions: The present findings provide novel insights into the role of ubiquitin in immune regulation in a melanoma mouse model, and suggest ubiquitin as the causal link between allogeneic blood transfusion therapy and poor cancer prognosis.

• allogeneic blood transfusion
• melanoma
• metastasis
• transfusion-related immune modulation (TRIM)
• ubiquitin

• 5-FC, 5-fluorocytosine
• AAT, a1-antitrypsin
• APCs, antigen presenting cells
• ASC, adipose-derived stromal/stem cells
• Abs, antibodies
• Ang1, angiopoietin-1
• BD, bone defect
• BMMSCs, bone marrow-derived mesenchymal stromal cells
• Biology
• Bone
• CAM, cell adhesion molecules
• CCL5, chemokine ligand 5
• CCR2, chemokine receptor 2
• CD, classification determinants
• CD, cytosine deaminase
• CLUAP1, clusterin associated protein 1
• CSPG4, Chondroitin sulfate proteoglycan 4
• CX3CL1, chemokine (C-X3-C motif) ligand 1
• CXCL12/CXCR4, C-X-C chemokine ligand 12/ C-X-C chemokine receptor 4
• CXCL12/CXCR7, C-X-C chemokine ligand 12/ C-X-C chemokine receptor 7
• CXCR4, chemokine receptor type 4
• Cell
• DBM, Demineralized Bone Marrow
• DKK1, dickkopf-related protein 1
• ECM, extracellular matrix
• EMT, epithelial-mesenchymal transition
• FGF-2, fibroblast growth factors-2
• FGF-7, fibroblast growth factors-7
• GD2, disialoganglioside 2
• HER2, human epidermal growth factor receptor 2
• HGF, hepatocyte growth factor
• HMGB1/RACE, high mobility group box-1 protein/ receptor for advanced glycation end-products
• IDO, indoleamine 2,3-dioxygenase
• IFN-α, interferon alpha
• IFN-β, interferon beta
• IFN-γ, interferon gamma
• IGF-1R, insulin-like growth factor 1 receptor
• IL-10, interleukin-10
• IL-12, interleukin-12
• IL-18, interleukin-18
• IL-1b, interleukin-1b
• IL-21, interleukin-21
• IL-2a, interleukin-2a
• IL-6, interleukin-6
• IL-8, interleukin-8
• IL11RA, Interleukin 11 Receptor Subunit Alpha
• MAGE, melanoma antigen gene
• MCP-1, monocyte chemoattractant protein-1
• MMP-2, matrix metalloproteinase-2
• MMP2/9, matrix metalloproteinase-2/9
• MRP, multidrug resistance protein
• MSCs, mesenchymal stem/stromal cells
• Mesenchymal
• NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells
• OPG, osteoprotegerin
• Orthopaedic
• PBS, phosphate-buffered saline
• PDGF, platelet-derived growth factor
• PDX, patient derived xenograft
• PEDF, pigment epithelium-derived factor
• PGE2, prostaglandin E2
• PI3K/Akt, phosphoinositide 3-kinase/protein kinase B
• PTX, paclitaxel
• RANK, receptor activator of nuclear factor kappa-B
• RANKL, receptor activator of nuclear factor kappa-B ligand
• RBCs, red blood cells
• RES, reticuloendothelial system
• RNA, ribonucleic acid
• Regeneration
• SC, stem cells
• SCF, stem cells factor
• SDF-1, stromal cell-derived factor 1
• STAT-3, signal transducer and activator of transcription 3
• Sarcoma
• Stromal
• TAAs, tumour-associated antigens
• TCR, T cell receptor
• TGF-b, transforming growth factor beta
• TGF-b1, transforming growth factor beta 1
• TNF, tumour necrosis factor
• TNF-a, tumour necrosis factor alpha
• TRAIL, tumour necrosis factor related apoptosis-inducing ligand
• Tissue
• VEGF, vascular endothelial growth factor
• VEGFR, vascular endothelial growth factor receptor
• WBCs, white blood cell
• hMSCs, human mesenchymal stromal cells
• rh-TRAIL, recombinant human tumour necrosis factor related apoptosis-inducing ligand

Tumor progression from an expanded cell population in a primary location to disseminated lethal growths subverts attempts at cures. It has become evident that these steps are driven in a large part by cancer cell-extrinsic signaling from the tumor microenvironment (TME), one cellular component of which is becoming more appreciated for potential modulation of the cancer cells directly and the TME globally. That cell is a heterogenous population referred to as adult mesenchymal stem cells/multipotent stromal cells (MSCs). Herein, we review emerging evidence as to how these cells, both from distant sources, mainly the bone marrow, or local resident cells, can impact the progression of solid tumors. These nascent investigations raise more questions than they answer but paint a picture of an orchestrated web of signals and interactions that can be modulated to impact tumor progression.

• cancer-associated epithelial-to-mesenchymal transition
• matricellular proteins
• secretome

• Adult Stem Cells/metabolism
• Adult Stem Cells/pathology
• Animals
• Disease Progression
• Epithelial-Mesenchymal Transition
• Humans
• Mesenchymal Stem Cells/metabolism
• Mesenchymal Stem Cells/pathology
• Neoplasms/metabolism
• Neoplasms/pathology
• Signal Transduction
• Tumor Microenvironment

• I01 BX001017 BLRD VA
• I01 BX003368 BLRD VA
• UH3 TR000496 NIH HHS

AMD3100 (plerixafor, Mozobil®) was first identified as an anti-HIV agent specifically active against the T4-lymphotropic HIV strains, as it selectively blocked the CXCR4 receptor. Through interference with the interaction of CXCR4 with its natural ligand, SDF-1 (also named CXCL12), it also mobilized the CD34⁺stem cells from the bone marrow into the peripheral blood stream. In December 2008, AMD3100 was formally approved by the US FDA for autologous transplantation in patients with Non-Hodgkin’s Lymphoma or multiple myeloma. It may be beneficially used in various other malignant diseases as well as hereditary immunological disorders such as WHIM syndrome, and physiopathological processes such as hepatopulmonary syndrome.

• AMD3100
• CXCR4
• MM
• Mozobil®
• NHL
• WHIM
• stem cells

• Adult mesenchymal stem cells
• Experimental cancer cytotherapy
• Gene delivery vehicles
• Tumor microenvironment
• Umbilical cord matrix stem cells
• Wharton’s jelly

Osteosarcoma is the most common primary bone malignancy. Recently, studies showed chemokine receptor 4 (CXCR4) played a critical role in osteosarcoma. However, the regulation of CXCR4 is not fully understood. microRNAs are short, non‐coding RNAs that play an important roles in post‐transcriptional regulation of gene expression in a variety of diseases including osteosarcoma. miR‐613 is a newly discovered miRNA and has been reported to function as a tumor suppressor in many cancers. In this study, we confirmed that both Stromal Cell‐Derived Factor (SDF‐1) and CXCR4 could be prognostic markers for osteosarcoma. Meanwhile this study found that SDF‐1/CXCR4 pathway regulated osteosarcoma cells proliferation, migration and reduced apoptosis. Besides, we demonstrated that miR‐613 was significantly downregulated in osteosarcoma patients. Elevated expression of miR‐613 directly suppressed CXCR4 expression and then decreased the proliferation, migration and induced apoptosis of osteosarcoma cells. Moreover, our study found that CXCR4 promoted the development of lung metastases and inhibition of CXCR4 by miR‐613 reduced lung metastases. These data indicated that CXCR4 mediated osteosarcoma cell growth and lung metastases and this effect can be suppressed by miR‐613 through directly downregulating CXCR4.

• CXCR4
• SDF-1
• lung metastasis
• miR-613
• steosarcoma

It has been reported mesenchymal stem cells (MSCs) are recruited to and become integral parts of the tumor microenvironment. MSCs might have an active role in solid tumor progression, especially cancer metastasis. However, the contribution of MSCs in the process of cancer metastasis is still controversial. In this review, we performed a meta-analysis on the effects of MSCs administration on cancer metastasis based on published preclinical studies.

The PRISMA guidelines were used. A total of 42 publications met the inclusion criteria. Outcome data on the incidence and the number of cancer metastasis as well as study characteristics were extracted. Quality of the studies was assessed according to SYRCLE Risk of Bias tool. Random-effects meta-analysis was used to pool estimates.

Of the 42 studies included, 32 reported that MSCs administration promoted outcome events (numbers or incidences of cancer metastasis), and 39 reported data suitable for meta-analysis. The median effect size (RR) was 2.04 for the incidence of cancer metastasis (95% CI 1.57–2.65, I² = 21%), and the median effect size (SMD) was 1.23 for the number of cancer metastasis (95% CI 0.43–2.03, I² = 89%). Heterogeneity was observed, with the greater impact based on study length and different ways of metastasis measurement and MSCs administration.

Our results suggested MSCs administration increased the number and the incidence of cancer metastasis in experimental cancer models. High heterogeneity and poor reported risk of bias limit the quality of these findings. Further preclinical studies with better design and adequate reporting are still needed.

The online version of this article (10.1186/s12967-018-1484-9) contains supplementary material, which is available to authorized users.

• Animal model
• Mesenchymal stem cells
• Meta-analysis
• Neoplasm metastasis

• bone
• cancer-associated fibroblasts
• dormancy
• mesenchymal stem cells
• metastasis
• metastatic niche
• stromal cells
• tumor microenvironment

• Animals
• Bone Neoplasms/pathology
• Bone Neoplasms/secondary
• Cell Proliferation
• Homeostasis
• Humans
• Mesenchymal Stem Cells/physiology
• Stem Cell Niche
• Tumor Microenvironment

• 17367 Cancer Research UK
• MR/N022556/1 Medical Research Council

• colon cancer
• hypoxia-inducible factor 1-1α
• oxaliplatin
• thalidomide
• vascular endothelial growth factor-A

During tumorigenesis and development, participation of the tumor microenvironment is not negligible. As an important component in the tumor microenvironment, mesenchymal stem cells (MSCs) have been corroborated to mediate proliferation, metastasis, and drug resistance in many cancers, including osteosarcoma. What’s more, because of tumor site tropism, MSCs can be engineered to be loaded with therapeutic agents so that drugs can be precisely delivered to tumor lesions. In this review, we mainly discuss recent advances concerning the functions of MSCs in osteosarcoma and their possible clinical applications in the future.

• Clinical applications
• Drug resistance
• MSCs
• Metastasis
• Osteosarcoma

• Extracellular vesicles
• IL-6
• Mesenchymal stroma
• Metabolites
• Microenvironment
• Osteosarcoma

Osteosarcoma (OS) is the most common malignant primary bone tumor disease. HIF-1α was predicted to be the target gene of microRNA-20b (miR-20b). The present study was designed to illustrate the effect of miR-20b in regulating osteosarcoma via targeting HIF-1α. In this study, we found that the expression of HIF-1α was significantly increased, while miR-20b obviously decreased in OS patients and OS cell lines compared with healthy controls. Moreover, the luciferase report confirmed the targeting reaction between miR-20b and HIF-1α. Additionally, the overexpression of miR-20b suppressed the invasion and growth of both MG63 and U2OS cells, and inhibited the expressions of HIF-1α and VEGF pathway proteins, while the inhibition of miR-20b led to the reverse results. Furthermore, the overexpression of HIF-1α affected the suppression effect of miR-20b in MG63 cells, indicating that miR-20b suppresses the tumor cell process via inhibiting the expression of HIF-1α. Taken together, our results suggest that the upregulation of miR-20b affects the expression of HIF-1α, downregulates the VEGF pathway proteins, and suppresses cell invasion and proliferation rate. These results provide a potential therapeutic strategy for osteosarcoma.

Critical limb ischemia (CLI) is one of the most severe forms of peripheral artery diseases, but current treatment strategies do not guarantee complete recovery of vascular blood flow or reduce the risk of mortality. Recently, human bone marrow derived mesenchymal stem cells (MSCs) have been reported to have a paracrine influence on angiogenesis in several ischemic diseases. However, little evidence is available regarding optimal cell doses and injection frequencies. Thus, the authors undertook this study to investigate the effects of cell dose and injection frequency on cell survival and paracrine effects. MSCs were injected at 10⁶ or 10⁵ per injection (high and low doses) either once (single injection) or once in two consecutive weeks (double injection) into ischemic legs. Mice were sacrificed 4 weeks after first injection. Angiogenic effects were confirmed in vitro and in vivo, and M2 macrophage infiltration into ischemic tissues and rates of limb salvage were documented. MSCs were found to induce angiogenesis through a paracrine effect in vitro, and were found to survive in ischemic muscle for up to 4 weeks dependent on cell dose and injection frequency. In addition, double high dose and low dose of MSC injections increased vessel formation, and decreased fibrosis volumes and apoptotic cell numbers, whereas a single high dose did not. Our results showed MSCs protect against ischemic injury in a paracrine manner, and suggest that increasing injection frequency is more important than MSC dosage for the treatment CLI.

• Bone marrow derived mesenchymal stem cells
• Critical limb ischemia
• High MSCs dose injection
• High frequency injection

• AQP1
• BM-MSCs
• hepatocellular carcinoma
• invasion
• migration
• osteosarcoma

• Aquaporin 1/antagonists & inhibitors
• Aquaporin 1/metabolism
• Bone Marrow Cells/cytology
• Bone Neoplasms/metabolism
• Bone Neoplasms/pathology
• Carcinoma, Hepatocellular/metabolism
• Carcinoma, Hepatocellular/pathology
• Cell Line, Tumor
• Cell Movement/drug effects
• Cell Proliferation/drug effects
• Culture Media, Conditioned/pharmacology
• Hematopoietic Stem Cells/cytology
• Hematopoietic Stem Cells/metabolism
• Humans
• Liver Neoplasms/metabolism
• Liver Neoplasms/pathology
• Osteosarcoma/metabolism
• Osteosarcoma/pathology
• Tetraethylammonium/pharmacology
• Tumor Microenvironment/drug effects

• migration
• matrix metalloproteinases
• osteosarcoma
• tectorigenin

• Antineoplastic Agents/pharmacology
• Bone Neoplasms/drug therapy
• Bone Neoplasms/genetics
• Bone Neoplasms/pathology
• Caspase 3/metabolism
• Cell Line, Tumor
• Down-Regulation/drug effects
• Gene Expression Regulation, Neoplastic/drug effects
• Humans
• Isoflavones/pharmacology
• Matrix Metalloproteinase Inhibitors/pharmacology
• Matrix Metalloproteinases/metabolism
• Osteosarcoma/drug therapy
• Osteosarcoma/genetics
• Osteosarcoma/pathology

Endothelial progenitor cells (EPCs) are important in tumor angiogenesis. Stromal cell-derived factor-1α (SDF-1α) and its receptor C-X-C chemokine receptor type 4 (CXCR4) are key in stem cell homing. Melittin, a component of bee venom, exerts antitumor activity, however, the underlying mechanisms remain to be elucidated. The present study aimed to assess the effects of melittin on EPCs and angiogenesis in a mouse model of osteosarcoma. UMR-106 cells and EPCs were treated with various concentrations of melittin and cell viability was determined using the MTT assay. EPC adherence, migration and tube forming ability were assessed. Furthermore, SDF-1α, AKT and extracellular signal-regulated kinase (ERK)1/2 expression levels were detected by western blotting. Nude mice were inoculated with UMR-106 cells to establish an osteosarcoma mouse model. The tumors were injected with melittin, and its effects were assessed by immunohistochemistry and immunofluorescence. Melittin decreased the viability of UMR-106 cells and EPCs. In addition, it decreased EPC adhesion, migration and tube formation when compared with control and SDF-1α-treated cells. Melittin decreased the expression of phosphorylated (p)-AKT, p-ERK1/2, SDF-1α and CXCR4 in UMR-106 cells and EPCs when compared with the control. The proportions of cluster of differentiation (CD)34/CD133 double-positive cells were 16.4±10.4% in the control, and 7.0±4.4, 2.9±1.2 and 1.3±0.3% in tumors treated with 160, 320 and 640 µg/kg melittin per day, respectively (P<0.05). At 11 days, melittin reduced the tumor size when compared with that of the control (control, 4.8±1.3 cm³; melittin, 3.2±0.6, 2.6±0.5, and 2.0±0.2 cm³ for 160, 320 and 640 µg/kg, respectively; all P<0.05). Melittin decreased the microvessel density, and SDF-1α and CXCR4 protein expression levels in the tumors. Melittin may decrease the effect of osteosarcoma on EPC-mediated angiogenesis, possibly via inhibition of the SDF-1α/CXCR4 signaling pathway.

• Bone marrow-derived mesenchymal stem cells (BM-MSCs)
• Chemokine receptor type 4 (CXCR4)
• Novel CXCR4 inhibitor
• Tumor invasion

• Bone Neoplasms/drug therapy
• Bone Neoplasms/pathology
• Carcinoma, Hepatocellular/drug therapy
• Carcinoma, Hepatocellular/pathology
• Cell Line, Tumor
• Cell Movement
• Epithelial-Mesenchymal Transition
• Extracellular Signal-Regulated MAP Kinases/metabolism
• Humans
• Liver Neoplasms/drug therapy
• Liver Neoplasms/pathology
• Mesenchymal Stem Cells/physiology
• Neoplasm Invasiveness
• Osteosarcoma/drug therapy
• Osteosarcoma/pathology
• Proto-Oncogene Proteins c-akt/metabolism
• Receptors, CXCR4/antagonists & inhibitors
• Wound Healing

Conventional therapy of primary bone tumors includes surgical excision with wide resection, which leads to physical and aesthetic defects. For reconstruction of bone and joints, allografts can be supplemented with mesenchymal stem cells (MSCs). Similarly, adipose tissue transfer (ATT) is supplemented with adipose-derived stem cells (ADSCs) to improve the efficient grafting in the correction of soft tissue defects. MSC-like cells may also be used in tumor-targeted cell therapy. However, MSC may have adverse effects on sarcoma development. In the present study, human ADSCs, MSCs and pre-osteoclasts were co-injected with human MNNG-HOS osteosarcoma cells in immunodeficient mice. ADSCs and MSCs, but not the osteoclast precursors, accelerated the local proliferation of MNNG-HOS osteosarcoma cells. However, the osteolysis and the metastasis process were not exacerbated by ADSCs, MSCs, or pre-osteoclasts. In vitro proliferation of MNNG-HOS and Saos-2 osteosarcoma cells was increased up to 2-fold in the presence of ADSC-conditioned medium. In contrast, ADSC-conditioned medium did not change the dormant, quiescent state of osteosarcoma cells cultured in oncospheres. Due to the enhancing effect of ADSCs/MSCs on in vivo/in vitro proliferation of osteosarcoma cells, MSCs may not be good candidates for osteosarcoma-targeted cell therapy. Although conditioned medium of ADSCs accelerated the cell cycle of proliferating osteosarcoma cells, it did not change the quiescent state of dormant osteosarcoma cells, indicating that ADSC-secreted factors may not be involved in the risk of local recurrence.

• Adipose tissue transfer
• Cell cycle
• Mesenchymal stem cell
• Osteosarcoma
• Quiescence

To determine the clinical significance of C-X-C chemokine receptor type 4 (CXCR4) and β-catenin in osteosarcoma, their protein expression levels were assessed in 96 osteosarcoma and 20 osteochondroma cases using immunohistochemistry. Additionally, CXCR4 and β-catenin mRNA expression levels were measured in 16 fresh osteosarcoma and 16 adjacent healthy tissue samples using fluorescent reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In the osteosarcoma samples, the positive CXCR4 protein expression rate was significantly higher than the rate in the osteochondroma samples (68.75 vs. 20.00%; P<0.01). Furthermore, β-catenin protein expression was detected in 61.46% of osteosarcoma cases and 25.00% of osteochondroma cases. Similarly, the RT-qPCR data identified increased CXCR4 and β-catenin mRNA expression levels in the osteosarcoma compared with adjacent control tissues. It was determined that CXCR4 (P<0.01) and β-catenin (P<0.05) expression were significantly associated with the clinical Enneking stage, metastasis and survival of osteosarcoma. Furthermore, multivariate analysis identified CXCR4 and β-catenin protein expression levels, as well as clinical stage and metastasis, as significant risk factors for survival in patients with osteosarcoma (P<0.05). In conclusion, the present study determined that CXCR4 and β-catenin are abnormally expressed in osteosarcoma tissues, and, therefore, may be important during osteosarcoma progression.

• C-X-C chemokine receptor type 4
• immunohistochemistry
• osteosarcoma
• survival
• β-catenin

Osteosarcoma (OS) has an unfavorable prognosis and tends to metastasize to lung tissue. Although the CXCL12-CXCR4 axis appears to affect progression and metastasis in numerous tumors, its mechanism and downstream pathways in OS remain unclear. We used western blotting and flow cytometry to detect CXCR4 and CXCR7 expression in two OS cell lines (LM8 and Dunn). An MTT assay was used to evaluate the effects of CXCL12 and AMD3100, a specific CXCR4 antagonist, on cell viability. Flow cytometry was utilized to analyze changes in apoptosis induced by serum deprivation following treatment with CXCL12 and AMD3100. A Transwell assay was used to assess cell migration in response to CXCL12 and AMD3100. Western blotting was performed to identify the phosphorylation of signaling molecules (JNK, c-Jun, Akt, p38 and Erk1/2) and expression of caspase-3 and -8, and PARP. Mouse models were employed to evaluate AMD3100 inhibition of primary OS growth and lung metastasis in vivo. CXCR4 expression was detected in LM8 but not Dunn cells, and neither cell line expressed CXCR7. The addition of CXCL12 induced the survival and migration of serum-starved CXCR4⁺ LM8 cells activating JNK and Akt pathways, which were abrogated by adding AMD3100. However, similar results were not observed in CXCR4⁻ Dunn cells. CXCL12 protected LM8, but not Dunn cells, from apoptosis induced by serum deprivation by suppressing PARP cleavage, which was partly reversed by AMD3100. In a mouse model, AMD3100 reduced primary tumor growth and lung metastasis compared with the controls. Thus, the CXCL12-CXCR4 axis regulated OS survival and metastasis through the JNK and Akt pathways, and blocking them with AMD3100 was found to be a potential OS treatment.

Human bone marrow mesenchymal stem cells (hBM-MSCs) favor tumor growth and metastasis in vivo and in vitro. Neovascularization is involved in several pathological conditions, including tumor growth and metastasis. Previous studies have demonstrated that human bone marrow MSC-derived conditioned medium (hBM-MSC-CM) can promote tumor growth by inducing the expression of vascular epidermal growth factor (VEGF) in tumor cells. However, the effect of BM-MSCs on tumor lymph vessel formation has yet to be elucidated. In the present study, the effect of BM-MSCs on processes involved in lymph vessel formation, including tube formation, migration and proliferation, was investigated in human-derived lymphatic endothelial cells (HDLECs). It was identified that hBM-MSC-CM promoted the tube formation and migration of HDLECs. In addition, tumor cells were revealed to participate in lymph vessel formation. In the present study, the SGC-7901, HGC-27 and GFP-MCF-7 cell lines were treated with hBM-MSC-CM. The results demonstrated that the expression of the lymph-associated markers, prospero homeobox protein 1 and VEGF receptor-3, were increased in the SGC-7901 and HGC-27 cell lines, but not in the GFP-MCF-7 cells. The tube formation assay demonstrated that the HGC-27 cells treated with hBM-MSC-CM for 20 days underwent tube formation. These findings indicate that hBM-MSC-CM can promote tube formation in HDLECs and HGC-27 cells, which may be associated with lymph vessel formation during tumor growth and metastasis.

• lymph vessel
• mesenchymal stem cell
• tumor growth

• Cell Migration
• Lung Injury
• Mesenchymal Stem Cells (MSCs)
• Migration
• Transplantation

Osteosarcoma (OS) is the most frequent primary bone sarcoma and tends to develop pulmonary metastasis. Studies have shown that mesenchymal stem cells (MSCs) are involved in OS growth and metastasis, but the mechanism remains unclear. The aim of the present study was to identify whether homologous MSCs could promote the growth and metastasis of OS in rats with a normal immune system. The OS cell line, UMR-106, which originally derives from a Sprague-Dawley (SD) rat-transplantable osteogenic sarcoma with an osteoblastic phenotype, has a strong carcinogenic capability and a high lung metastasis. Xenotransplanted models of UMR-106 with or without MSCs injected through the tibia (IT) or caudal vein (IV) were established. SD rats were randomly divided into six groups: Control, UMR-106 (IT), MSCs (IV), UMR-106 (IT) + MSCs (IV), UMR-106 (IV) and UMR-106 (IV) + MSCs (IV). Following injection, all rats were sacrificed at week 5, and the volume and quantity of metastatic sarcoma and the serum alkaline phosphatase levels were measured. There was no metastatic sarcoma in the liver, spleen and kidney in all groups. The rats in the MSCs (IV) + UMR-106 (IV) group showed a significantly higher volume and number of pulmonary metastatic tumors than those of the UMR-106 (IV) group. In pulmonary metastatic tissues, MSCs were found in the MSCs (IV) + UMR-106 (IV) group, but not in the UMR-106 (IT) + MSCs (IV) group. Notably, the expression of vascular endothelial growth factor (VEGF) was increased in the MSCs + UMR-106 cells co-culture system. The present study indicated that MSCs can significantly promote the pulmonary metastasis of the rat OS cell line, UMR-106, with a normal immune system, and VEGF was involved in MSC-promoted UMR-106 emergence and growth of pulmonary metastasis.

• mesenchymal stem cells
• metastasis
• osteosarcoma
• rat
• vascular endothelial growth factor