Current treatment of osteosarcoma

Redox-active vitamin C suppresses human osteosarcoma growth by triggering intracellular ROS-iron-calcium signaling crosstalk and mitochondrial dysfunction

Pharmacological vitamin C (VC) has gained attention for its pro-oxidant characteristics and selective ability to induce cancer cell death. However, defining its role in cancer has been challenging due to its complex redox properties. In this study, using a human osteosarcoma (OS) model, we show that the redox-active property of VC is critical for inducing non-apoptotic cancer cell death via intracellular reactive oxygen species (ROS)-iron-calcium crosstalk and mitochondrial dysfunction. In both 2D and 3D OS cell culture models, only the oxidizable form of VC demonstrated potent dose-dependent cytotoxicity, while non-oxidizable and oxidized VC derivatives had minimal effects. Live-cell imaging showed that only oxidizable VC caused a surge in cytotoxic ROS, dependent on iron rather than copper. Inhibitors of ferroptosis, a form of iron-dependent cell death, along with classical apoptosis inhibitors, were unable to completely counteract the cytotoxic effects induced by VC. Further pharmacological and genetic inhibition analyses showed that VC triggers calcium release through inositol 1,4,5-trisphosphate receptors (IP3Rs), leading to mitochondrial ROS production and eventual cell death. RNA sequencing revealed down-regulation of genes involved in the mitochondrial electron transport chain and oxidative phosphorylation upon pharmacological VC treatment. Consistently, high-dose VC reduced mitochondrial membrane potential, oxidative phosphorylation, and ATP levels, with ATP reconstitution rescuing VC-induced cytotoxicity. In vivo OS xenograft studies demonstrated reduced tumor growth with high-dose VC administration, concomitant with the altered expression of mitochondrial ATP synthase (MT-ATP). These findings emphasize VC's potential clinical utility in osteosarcoma treatment by inducing mitochondrial metabolic dysfunction through a vicious intracellular ROS-iron-calcium cycle.

Sociodemographic Disparities in Presentation and Survival of Pediatric Bone Cancers

Osteosarcoma (OST) and Ewing sarcoma (ES) are the most common pediatric bone cancers. Patients with metastatic disease at diagnosis have poorer outcomes compared with localized disease. Using the Surveillance, Epidemiology, and End Results registries, we identified children and adolescents diagnosed with OST or ES between 2004 and 2015. We examined whether demographic and socioeconomic disparities were associated with a higher likelihood of metastatic disease at diagnosis and poor survival outcomes. In OST, Hispanic patients and those living in areas of high language isolation were more likely to have metastatic disease at diagnosis. Regardless of metastatic status, OST patients with public insurance had increased odds of death compared to those with private insurance. Living in counties with lower education levels increased odds of death for adolescents with metastatic disease. In ES, non-White adolescents had higher odds of death compared with white patients. Adolescents with metastatic ES living in higher poverty areas had increased odds of death compared with those living in less impoverished areas. Disparities in both diagnostic and survival outcomes based on race, ethnicity, and socioeconomic factors exist in pediatric bone cancers, potentially due to barriers to care and treatment inequities.

Cellular functions and molecular mechanisms of ubiquitination in osteosarcoma

Although some advances have been made in the treatment of osteosarcoma in recent years, surgical resection remains the mainstream treatment. Initial and early diagnosis of osteosarcoma could be very difficult to achieve due to the insufficient sensitivity for the means of examination. The distal metastasis of osteosarcoma also predicts the poor prognosis of osteosarcoma. In order to solve this series of problems, people begin to discover a new method of diagnosing and treating osteosarcoma. Ubiquitination, as an emerging posttranslational modification, has been shown to be closely related to osteosarcoma in studies over the past decades. In general, this review describes the cellular functions and molecular mechanisms of ubiquitination during the development of osteosarcoma.

Risk factors associated with 30-day complications following lower extremity sarcoma surgery: A national surgical quality improvement project analysis

BACKGROUND

Our study aims to identify risk factors associated with complications in lower extremity (LE) sarcoma surgery, as well as the prevalence and complications associated with concurrent plastic surgery procedures (CPSP).

METHODS

ACS-NSQIP database was accessed to identify patients treated for LE sarcoma (2010-2019). Patient demographics, preoperative lab, comorbidities, tumor type, location, principle procedure, and presence/characteristics of CPSPs were recorded. Thirty-day soft tissue complications were analyzed. Bivariate and multivariate logistic regression was performed on IBM SPSS.™ RESULTS: Nine hundred eighteen patients were included (483 males and 435 females), average age and body mass index (BMI) of 57 and 27.4 kg/m,² respectively. Comorbidities included smoking (13.9%, 128), hypertension (37.3%, 342), and insulin-dependent diabetes (3.7%, 34). Preoperative lab values included albumin <3.5 (6.8%, 63), hematocrit <30% (8.2%, 75), and platelet count <150 000 (5.9%, 54). Thirty-day soft tissue complication rate was 5.7% (52 of 918). On multivariate logistic regression, increased age (p = 0.039), higher BMI (p = 0.017), and longer operative times (p = 0.002) were significant risk factors independently associated with soft tissue complications.

CONCLUSIONS

Soft tissue complications within 30 days occur in 6% of patients. Graft procedures carry a 20% risk of complications. Risk factors independently associated with complications include increased age, increased BMI, and longer operative times.

Surgical Treatment of Bone Sarcoma

Bone sarcomas are rare primary malignant mesenchymal bone tumors. The three main entities are osteosarcoma, chondrosarcoma, and Ewing sarcoma. While prognosis has improved for affected patients over the past decades, bone sarcomas are still critical conditions that require an interdisciplinary diagnostic and therapeutic approach. While radiotherapy plays a role especially in Ewing sarcoma and chemotherapy in Ewing sarcoma and osteosarcoma, surgery remains the main pillar of treatment in all three entities. After complete tumor resection, the created bone defects need to be reconstructed. Possible strategies are implantation of allografts or autografts including vascularized bone grafts (e.g., of the fibula). Around the knee joint, rotationplasty can be performed or, as an alternative, the implantation of (expandable) megaprostheses can be performed. Challenges still associated with the implantation of foreign materials are aseptic loosening and infection. Future improvements may come with advances in 3D printing of individualized resection blades/implants, thus also securing safe tumor resection margins while at the same time shortening the required surgical time. Faster osseointegration and lower infection rates may possibly be achieved through more elaborate implant surface structures.

Bone tumors effective therapy through functionalized hydrogels: current developments and future expectations

Primary bone tumors especially, sarcomas affect adolescents the most because it originates from osteoblasts cells responsible for bone growth. Chemotherapy, surgery, and radiation therapy are the most often used clinical treatments. Regrettably, surgical resection frequently fails to entirely eradicate the tumor, which is the primary cause of metastasis and postoperative recurrence, leading to a high death rate. Additionally, bone tumors frequently penetrate significant regions of bone, rendering them incapable of self-repair, and impairing patients' quality of life. As a result, treating bone tumors and regenerating bone in the clinic is difficult. In recent decades, numerous sorts of alternative therapy approaches have been investigated due to a lack of approved treatments. Among the novel therapeutic approaches, hydrogel-based anticancer therapy has cleared the way for the development of new targeted techniques for treating bone cancer and bone regeneration. They include strategies such as co-delivery of several drug payloads, enhancing their biodistribution and transport capabilities, normalizing accumulation, and optimizing drug release profiles to decrease the limitations of current therapy. This review discusses current advances in functionalized hydrogels to develop a new technique for treating bone tumors by reducing postoperative tumor recurrence and promoting tissue repair.

Evaluation of tumor-prostheses over time: Complications, functional outcome, and comparative statistical analysis after resection and reconstruction in orthopedic oncologic conditions in the lower extremities

Objectives:

Previous multicenter studies report variable outcomes and failure rates after tumor-prosthetic reconstructions. The purpose of this study was (1) to evaluate implant survival, limb survival, and functional outcome in a cohort of patients who underwent resection of primary malignancies or aggressive benign bone tumors and reconstruction with modern tumor-prostheses in the lower extremities and (2) to provide comparison to a historical cohort on previous generations of tumor-prostheses from the same center.

Methods:

A longitudinal retrospective single-center study of 72 consecutive patients (F/M = 30/42), mean age = 44 (range = 7–84) years with bone, soft tissue sarcoma adjacent to bone (n = 69), and aggressive benign bone tumors (n = 3) having surgery between 2006 and 2016 with bone resection and reconstruction with tumor-prostheses were compared to a historical cohort from1985 to 2005. Revisions were classified as major and minor revisions. Causes of failure were classified according to the Henderson classification. Fine and Gray competing risk analysis was used for assessing cumulative incidence for implant revision and limb amputation. Functional outcome was evaluated with Musculoskeletal Tumor Society Score system.

Results:

Forty-seven patients were alive at the end of the study. Mean follow-up was 6 years (range = 2–13 years). Ten-year cumulative risk of major revision was 18% (95% confidence interval = 9%–28%). Deep infection and recurrence of tumor caused most revisions in modern tumor-prostheses. Ten-year cumulative incidence of limb amputation was 11% (95% confidence interval = 3%–18%). According to the Henderson classification, the overall predominant failure mode was non-mechanical (n = 20, 51%). Mean Musculoskeletal Tumor Society Score was 20 (67%) (range = 0–30).

Conclusion:

A minimum of 2 years follow-up with modern modular tumor-prostheses demonstrated a relatively low risk of implant failure and amputation and also an acceptable functional outcome. No statistical difference of, implant survival, limb survival and functional outcome between tumor-prostheses over two time periods was observed, possibly explained by Type 2 error.

Research Progress of Natural Small-Molecule Compounds Related to Tumor Differentiation

Tumor differentiation is a therapeutic strategy aimed at reactivating the endogenous differentiation program of cancer cells and inducing cancer cells to mature and differentiate into other types of cells. It has been found that a variety of natural small-molecule drugs can induce tumor cell differentiation both in vitro and in vivo. Relevant molecules involved in the differentiation process may be potential therapeutic targets for tumor cells. Compared with synthetic drugs, natural small-molecule antitumor compounds have the characteristics of wide sources, structural diversity and low toxicity. In addition, natural drugs with structural modification and transformation have relatively concentrated targets and enhanced efficacy. Therefore, using natural small-molecule compounds to induce malignant cell differentiation represents a more targeted and potential low-toxicity means of tumor treatment. In this review, we focus on natural small-molecule compounds that induce differentiation of myeloid leukemia cells, osteoblasts and other malignant cells into functional cells by regulating signaling pathways and the expression of specific genes. We provide a reference for the subsequent development of natural small molecules for antitumor applications and promote the development of differentiation therapy.

A Novel Predictive Model Associated with Osteosarcoma Metastasis

Purpose

Long non-coding RNAs (lncRNAs) have diverse roles in modulating gene expression on both transcriptional and translational levels, but their involvement in osteosarcoma (OS) metastasis remains unknown.

Patients and Methods

Transcriptional and clinical data were downloaded from TARGET datasets. A total of seven lncRNAs screened by univariate cox regression, lasso regression, and multivariate cox regression analysis were used to establish the OS metastasis model. The area under the receiver operating characteristic curve (AUC) was used to evaluate the model.

Results

The established model showed exceptional predictive performance (1 year: AUC = 0.92, 95% Cl = 0.83-0.99; 3 years: AUC = 0.87, 95% Cl = 0.79-0.96; 5 years: AUC = 0.86, 95% Cl = 0.76-0.96). Patients in the high group had a poor survival outcome than those in the low group (p < 0.0001). GSEA analysis revealed that "NOTCH_SIGNALING" and "WNT_BETA_CATENIN_SIGNALING" were significantly enriched and that resting dendritic cells were associated with AL512422.1, AL357507.1, and AC006033.2 (p < 0.05).

Conclusion

Based on seven prognosis-related lncRNAs, we constructed a novel model with high reliability and accuracy for predicting metastasis in OS patients.

The cancer-related transcription factor Runx2 combined with osteopontin: a novel prognostic biomarker in resected osteosarcoma

PURPOSE

Osteosarcoma is the most common primary bone cancer in children and young adults. Recent experimental evidence has indicated that Runx2/OPN axis play important roles in the metastasis of osteosarcoma cells. The present study aimed to explore their relationship and prognostic significance in surgically resected osteosarcoma.

METHODS

The expression of runt-related transcription factor2(Runx2) and osteopontin (OPN) in clinical specimens from 105 osteosarcoma patients were detected by immunohistochemistry. The correlations between Runx2, OPN, and clinicopathologic data were analyzed by Chi-square (χ²) tests. The prognostic values were determined by univariate and multivariate survival analysis. The accuracy of oncologic outcome prediction was evaluated by receiver-operating characteristics curves.

RESULTS

The results showed there is a significant positive correlation between Runx2 and OPN expression at protein levels (P = 0.015). Runx2 and OPN were both independent predictors for overall survival and metastasis-free survival. When Runx2 and OPN were taken into consideration together, the predictive range was extended and the sensitivity was improved, and more significant and better biomarkers for osteosarcoma metastasis and survival.

CONCLUSIONS

These results suggest that a combined Runx2/OPN expression could be a valuable independent predictor of tumor metastasis and survival in osteosarcoma patients.

Transcriptional activators YAP/TAZ and AXL orchestrate dedifferentiation, cell fate, and metastasis in human osteosarcoma

Osteosarcoma (OS) is a molecularly heterogeneous, aggressive, poorly differentiated pediatric bone cancer that frequently spreads to the lung. Relatively little is known about phenotypic and epigenetic changes that promote lung metastases. To identify key drivers of metastasis, we studied human CCH-OS-D OS cells within a previously described rat acellular lung (ACL) model that preserves the native lung architecture, extracellular matrix, and capillary network. This system identified a subset of cells—termed derived circulating tumor cells (dCTCs)—that can migrate, intravasate, and spread within a bioreactor-perfused capillary network. Remarkably, dCTCs highly expressed epithelial-to-mesenchymal transition (EMT)-associated transcription factors (EMT-TFs), such as ZEB1, TWIST, and SOX9, which suggests that they undergo cellular reprogramming toward a less differentiated state by coopting the same epigenetic machinery used by carcinomas. Since YAP/TAZ and AXL tightly regulate the fate and plasticity of normal mesenchymal cells in response to microenvironmental cues, we explored whether these proteins contributed to OS metastatic potential using an isogenic pair of human OS cell lines that differ in AXL expression. We show that AXL inhibition significantly reduced the number of MG63.2 pulmonary metastases in murine models. Collectively, we present a laboratory-based method to detect and characterize a pure population of dCTCs, which provides a unique opportunity to study how OS cell fate and differentiation contributes to metastatic potential. Though the important step of clinical validation remains, our identification of AXL, ZEB1, and TWIST upregulation raises the tantalizing prospect that EMT-TF-directed therapies might expand the arsenal of therapies used to combat advanced-stage OS.

Mesenchymal stem cell-derived exosomes carrying microRNA-150 suppresses the proliferation and migration of osteosarcoma cells via targeting IGF2BP1

BACKGROUND

MicroRNA-150 (miR-150) plays a critical role in varied types of human cancers. In this study, we explored the effect and mechanism of mesenchymal stem cell (MSC)-derived exosomes (exo) carrying miR-150 (MSC-Exo-150) on the proliferation, migration, invasion, and apoptosis of osteosarcoma (OS) cells.

METHODS

MiR-150 expression in OS cell lines was assessed by quantitative reverse-transcription PCR (qRT-PCR). MSCs were transfected with cell-miR-67 or has-miR-150, and grouped as MSC-67 or MSC-150. Exosomes were isolated from each group, and separately named MSC-Exo-67, MSC-Exo-150 and MSC-Exo. MTT or flow cytometry assay was used to analyze the proliferation or apoptosis of U2SO and HOS cells, respectively. Wound healing or transwell assay was utilized to examine the migration or invasion of U2SO and HOS cells, respectively. The target relationship of miR-150 and insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) was established using StarBase2.0 and verified by dual-luciferase reporter gene analysis. Xenografted tumor model was established in rats to confirm the inhibitory effect of MSC-Exo-150 on the growth of xenografted tumor in vivo.

RESULTS

The expression of miR-150 was downregulated in OS cell lines, and significantly higher in MSC-150 cells than that in MSCs. MiR-150 was overexpressed in MSC-Exo-150 group compared with MSC-Exo group. After transfection of MSC-Exo-150 into U2SO and HOS cells, cell viability, mobility and invasion rate were decreased, and the cell apoptosis was increased. MiR-150 targeted IGF2BP1 and IGF2BP1 expression was negatively modulated by miR-150. Overexpression of IGF2BP1 reversed the anti-tumor effect of MSC-Exo-150 on HOS cells.

CONCLUSIONS

MSC-Exo-150 inhibited proliferation, migration, invasion, and induced apoptosis of OS cells by targeting IGF2BP1.

Triggering of Apoptosis in Osteosarcoma 143B Cell Line by Carbon Quantum Dots via the Mitochondrial Apoptotic Signal Pathway

Objectives

Carbon-based nanomaterials have gained attention in the field of biomedicine in recent years, especially for the treatment of complicated diseases such as cancer. Here, we report a novel carbon-based nanomaterial, named carbon quantum dots (CQDs), which has potential for cancer therapy. We performed a systematic study on the effects of CQDs on the osteosarcoma 143B cell line in vitro and in vivo.

Methods

Cell counting assay, the neutral red assay, lactic dehydrogenase assay, and fluorescein isothiocyanate (FITC) Annexin V/Propidium iodide (PI) were used to detect the cytotoxicity and apoptosis of CQDs on the 143B cell line. Intracellular reactive oxygen species (ROS) were detected by the oxidation-sensitive fluorescent probe 2′,7′-dichlorofluorescein diacetate. The JC-10 assay was used to detect the mitochondrial membrane potential (MMP) of 143B cells incubated with CQDs. The effects of CQDs on the 143B cell line were evaluated by Western blot and immunofluorescence analysis of apoptosis-related proteins Bax, Bcl-2, cytochrome-C, caspase-3, cleaved-caspase-3, PARP1, and cleaved-PARP1. Male tumor-bearing BALB/c nude mice were used to investigate the antitumor effects of CQDs, and the biosafety of CQDs in vivo was tested in male BALB/c mice by measuring weight changes, hematology tests, and histological analyses of major organs.

Results

CQDs exhibited a high cytotoxicity and induced apoptosis toward the 143B cell line. CQDs can also significantly increase the intracellular level of ROS and lower the mitochondrial membrane potential levels of 143B cells. CQDs increase apoptotic protein expression to induce apoptosis of 143B cells by triggering the mitochondrial apoptotic signaling pathway. The tumor volume in the CQD-treated mice was smaller than that in the control group, the tumor volume inhibition rate was 38.9%, and the inhibitory rate by tumor weight was 30.1%. All biosafety test indexes were within reference ranges, and neither necrosis nor inflammation was observed in major organs.

Conclusions

CQDs induced cytotoxicity in the 143B cell line through the mitochondrial apoptotic signaling pathway. CQDs not only showed an antitumor effect but also high biocompatibility in vivo. As a new carbon-based nanomaterial, CQDs usage is a promising method for novel cancer treatments.

Surgical Reconstruction Methods following Radical Excision of Distal Ulna Osteosarcoma in Both Skeletally Mature and Immature Patients

The distal ulna has always been considered to be expendable and its removal has been advocated for a variety of post-traumatic degenerative and oncological conditions but recent studies showed that the distal radioulnar joint allows supination and protonation of the forearm and is important to one's grip strength and lifting ability. Several prosthesis models have already been made to replace the mechanical functionality of the distal radioulnar joint. We present two cases of females aged 22 and 12 years, respectively, who presented with wrist pain and swelling without any history of trauma and with terminal degree limitation in wrist movements due to tenderness and swelling. Both of them did not have any distant metastasis upon radiographic staging. The skeletally mature patient underwent radical excision of the distal ulnar osteosarcoma and received a distal radioulnar joint replacement prosthesis (Scheker prosthesis). The other skeletally immature patient underwent radical excision of the involved distal ulnar osteosarcoma with stabilization of the residual ulnar stump using the extensor carpi ulnaris sling in a modified version of the Goldner and Hayes technique. Both of our patients were treated according to the protocols of our multidisciplinary clinic sarcoma team by starting with neoadjuvant chemotherapy, followed by surgery and adjuvant chemotherapy. Both registered an almost complete restoration of the normal wrist and hand function and were in complete remission for 26 and 24 months, respectively. Based on our literature review, these are some of the extremely rare cases in which the osteosarcoma affected an unusual site (the distal ulna where they underwent a rare type of reconstruction status following radical excision of a malignant tumor).

Thirty-Day Outcomes after Surgery for Primary Sarcomas of the Extremities: An Analysis of the NSQIP Database

Background

Primary bone and soft tissue sarcomas are rare tumors requiring wide surgical resection and reconstruction to achieve local control. Postoperative complications can lead to delays in adjuvant therapy, potentially affecting long-term oncologic outcomes. Understanding postoperative complication risks is essential; however, past studies are limited by small sample sizes.

Purpose

This study uses a large national registry to characterize the incidence of complications and mortality in the first thirty days following surgical management of primary bone and soft tissue sarcomas of the extremities.

Methods

A retrospective review of patients in the National Surgical Quality Improvement Program database was performed. Cases were identified using diagnosis codes for malignant neoplasm of soft tissue or bone and procedure codes for amputation and radical resection. The cohort was subdivided by bone versus soft tissue sarcoma, upper versus lower extremity, and amputation versus limb salvage.

Results

One thousand, one hundred eleven patients were identified. The most frequent complications were surgical site infections, sepsis, and venous thromboembolism. The overall incidence of complications was 14.0%. Unplanned readmission and reoperation occurred after 7.0% and 8.0% of cases, respectively. Thirty-day mortality was 0.3%, with one intraoperative death. Patient factors and complication rates varied by tumor location and surgical modality. Lower extremity cases were associated with higher rates of wound complications and infectious etiologies such as surgical site infections, urinary tract infections, and systemic sepsis. In contrast, patients undergoing amputation were more likely to experience major medical complications including acute renal failure, cardiac arrest, and myocardial infarction.

Conclusion

Approximately 1 in 7 patients will experience a complication in the first thirty days following surgery for primary bone and soft tissue sarcomas of the extremities. The unique risk profiles of lower extremity and amputation cases should be considered during perioperative planning and surveillance.

Outcomes for pediatric patients with osteosarcoma treated with palliative radiotherapy

BACKGROUND

Few studies have addressed the efficacy of palliative radiotherapy (RT) for pediatric osteosarcoma (OS), a disease generally considered to be radioresistant. We describe symptom relief, local control, and toxicity associated with palliative RT among children with OS.

PROCEDURE

Patients diagnosed with OS at age 18 and under and treated with RT for palliation of symptomatic metastases or local recurrence at the primary site from 1997 to 2017 were included. We retrospectively reviewed details of RT, symptom improvement, local control, survival, and toxicity.

RESULTS

Thirty-two courses of palliative RT were given to 20 patients with symptomatic metastatic and/or locally recurrent primary disease. The median equivalent dose in 2 Gy fractions (EQD2) was 40.0 Gy (range, 20.0-60.4). The median number of fractions per course was 15 (range, 5-39). Symptom improvement occurred in 24 (75%) courses of RT at a median time of 15.5 days (range, 3-43). In nine courses (37.5%), symptoms recurred after a median duration of symptom relief of 140 days (range, 1-882). Higher EQD2 correlated with longer duration of response (r = 0.39, P = 0.0003). Imaging revealed local failure in 3 of 14 courses followed with surveillance imaging studies (21.4%). The median time to progression was 12.9 months (range, 4.4-21.8). The median follow-up time following the first course of palliative RT was 17.5 months (range, 1.74-102.24), and median time to overall survival was 19.4 months. Toxicity was mild, with grade 2 toxicity occurring in one course (3.1%).

CONCLUSIONS

RT is an effective method of symptom palliation for patients with recurrent or metastatic OS, with higher delivered dose correlating with longer symptom relief and with little associated toxicity.

Extracellular vesicle-mediated delivery of miR-101 inhibits lung metastasis in osteosarcoma

Rationale: Extracellular vesicles (EVs) have emerged as novel mediators of cell-to-cell communication that are capable of the stable transfer of therapeutic microRNAs (miRNAs), and thus, EVs hold immense promise as a miRNA delivery system for cancer therapy. Additionally, as miRNA-containing EVs are secreted into circulation, miRNAs contained within plasma EVs may represent ideal biomarkers for diseases. The objective of this study was to characterize a potential tumor suppressor miRNA, miR-101, and explore the potential of miR-101 delivery via EVs for in vivo therapy of metastatic osteosarcoma as well as the potential value of plasma EV-packaged miR-101 (EV-miR-101) level for predicting osteosarcoma metastasis.

Methods: The relationship of miR-101 expression and osteosarcoma progression was investigated in osteosarcoma specimens by in situ hybridization (ISH), and the potential inhibitory effect of miR-101 was further investigated using in vivo models. Using prediction software analysis, the mechanism of action of miR-101 in osteosarcoma was explored using quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting and dual-luciferase assay. Adipose tissue-derived mesenchymal stromal cells (AD-MSCs) were transduced with lentiviral particles to obtain miR-101-enriched EVs. A Transwell assay and lung metastasis models of osteosarcoma were used to observe the effect of miR-101-enriched EVs on osteosarcoma invasiveness and metastasis. Detection of plasma EV-miR-101 levels was carried out in osteosarcoma patients and healthy controls by qRT-PCR.

Results: miR-101 expression was markedly lower in metastatic osteosarcoma specimens compared to non-metastatic specimens. Significantly fewer metastatic lung nodules were formed by Saos-2 cells overexpressing miR-101 and SOSP-9607 cells overexpressing miR-101 injected into mice. With increased miR-101 expression, B cell lymphoma 6 (BCL6) mRNA and protein expression levels were reduced, and miR-101 was found to exert its effects by directly targeting BCL6. AD-MSCs were successfully engineered to secrete miR-101-enriched EVs. Once taken up by osteosarcoma cells, these EVs showed suppressive effects on cell invasion and migration in vitro, and systemic administration of these EVs effectively suppressed metastasis in vivo with no significant side effects. Finally, the EV-miR-101 level was lower in osteosarcoma patients than in healthy controls and even lower in osteosarcoma patients with metastasis than in those without metastasis.

Conclusion: Our data support the function of miR-101 as a tumor suppressor in osteosarcoma via downregulation of BCL6. AD-MSC derived miR-101-enriched EVs represent a potential innovative therapy for metastatic osteosarcoma. EV-miR-101 also represents a promising circulating biomarker of osteosarcoma metastasis.

microRNA-26a-5p Promotes Proliferation and Migration of Osteosarcoma Cells by Targeting HOXA5 in vitro and in vivo

Background

Osteosarcoma is the most common primary malignant tumor of bone. However, the underlying pathogenic mechanisms are still unclear. miR-26a was an endogenous non-coding small RNAs that have been showed to play a critical role in regulating varieties of biological and pathological processes. In this study, we will investigate the function of miR-26a-5p in osteosarcoma cells.

Methods

In this study, we explored the role of miR-26a-5p in osteosarcoma cell lines using qPCR, detected the proliferation, cell cycle and cell migration by CCK-8, PI and transwell.

Results

We found that compared with noncancerous cells, miR-26a-5p was highly expressed in osteosarcoma cell lines, especially in U2OS cells. Overexpression of miR-26a-5p promotes cell proliferation, cell cycle, and cell migration, but inhibits cell apoptosis. But down-regulation of miR-26a-5p in U2OS cells exhibits opposite effects. We also confirmed that miR-26a-5p directly targets HOXA5 in U2OS cells. Overexpression of HOXA5 reversed the effect of miR-26a-5p on cell proliferation, migration, and apoptosis. Besides, we showed in that knock-down of miR-26a-5p or overexpression of HOXA5 increased cell sensitivity to chemotherapeutic drug paclitaxel.

Conclusion

These findings indicate that highly expressed miR-26a-5p in osteosarcoma cells, and promotes proliferation and migration, but inhibits apoptosis of osteosarcoma cells by targeting HOXA5 which suggest that miR-26a-5p could serve as a novel therapeutic target for osteosarcoma.

In vitro and in vivo effects of toceranib phosphate on canine osteosarcoma cell lines and xenograft orthotopic models

Canine osteosarcoma (OSA) is the most common primary malignant bone tumour in dogs, and it has a high metastatic rate and poor prognosis. Toceranib phosphate (TOC; Palladia, Zoetis) is a veterinary tyrosine kinase inhibitor that selectively inhibits VEGFR-2, PDGFRs and c-Kit, but its efficacy is not yet fully understood in the treatment of canine OSA. Here, we evaluated the functional effects of TOC on six OSA cell lines by transwell, wound healing and colony formation assays. Subsequently, two cell lines (Wall and Penny) were selected and were inoculated in mice by intrafemoral injection to develop an orthotopic xenograft model of canine OSA. For each cell line, 30 mice were xenografted; half of them were used as controls, and the other half were treated with TOC at 40 mg/kg body weight for 20 days. TOC inhibited cell growth of all cell lines, but reduced invasion and migration was only observed in Penny and Wall cell lines. In mice engrafted with Penny cells and subjected to TOC treatment, decreased tumour growth was observed, and PDGFRs and c-Kit mRNA were downregulated. Immunohistochemical analyses demonstrated a significant reduction of Ki67 staining in treated mice when compared to controls. The results obtained here demonstrate that TOC is able to slightly inhibit cell growth in vitro, while its effect is evident only in a Penny cell xenograft model, in which TOC significantly reduced tumour size and the Ki67 index without modifying apoptosis markers.

Development of an Oriental Medicine Discrimination Method through Analysis of Steroidal Saponins in Dioscorea nipponica Makino and Their Anti-Osteosarcoma Effects

To prevent confusing Dioscorea nipponica (DN), an Oriental medicine, with Dioscorea quinquelobata (DQ) and Dioscorea septemloba (DS), a simple and accurate quantitative analysis method using HPLC combined with ultraviolet (UV) detection was developed and verified with UPLC-QTOF/MS through identification of five saponin glycosides: protodioscin (1), protogracillin (2), pseudoprotodioscin (3), dioscin (4), and gracillin (5). The newly developed analysis method showed sufficient reproducibility (<1.91%) and accuracy (92.1%–102.6%) and was able to identify DN based on the presence of compound 3 (13.821 ± 0.037 mg/mL) and the absence of 5. Compound 1, which is present in DN at a relatively high level (159.983 ± 0.064 mg/mL), was also an important marker for identification. Among the three species, DN showed the strongest activation of apoptotic signaling in osteosarcoma cells, while the four compounds detected in DN showed IC₅₀ values of 6.43 (1), 10.61 (2), 10.48 (3), and 6.90 (4). In conclusion, the strong inhibitory effect of DN against osteosarcoma was confirmed to be associated with 1 and 4, which is also related to the quantitative results. Therefore, the results of this study might provide important information for quality control related to Oriental medicine.

Cisplatin bioconjugated enzymatic GNPs amplify the effect of cisplatin with acquiescence

Enzymatic gold nanoparticles (B-GNPs) have been synthesized using a natural anticancer agent bromelain (a cysteine protease) and these nanoparticles were used to bioconjugate Cisplatin (highly effective against osteosarcoma and lung cancer). Cisplatin bioconjugated bromelain encapsulated gold nanoparticles (B-C-GNPs) were found profoundly potent against same cancers at much lower concentration with minimum side effects due to the synergistic effect of bromelain. The B-C-GNPs have been observed to inhibit the proliferation of osteosarcoma cell lines Saos-2 and MG-63 with IC₅₀ estimation of 4.51 µg/ml and 3.21 µg/ml, respectively, and against small lung cancer cell line A-549 with IC₅₀ 2.5 µg/ml which is lower than IC₅₀ of cisplatin against same cell lines. The B-GNPs/B-C-GNPs were characterized by TEM, UV-Visible spectroscopy, Zeta potential and DLS to confirm the production, purity, crystalline nature, stability of nanoemulsion, size and shape distribution. The change in 2D and 3D conformation of bromelain after encapsulation was studied by Circular Dichroism and Fluorometry, respectively. It was found that after encapsulation, a 19.4% loss in secondary structure was observed, but tertiary structure was not altered significantly and this loss improved the anticancer activity. The confirmation of bioconjugation of cisplatin with B-GNPs was done by UV-Visible spectroscopy, TEM, FTIR, 2D ¹H NMR DOSY and ICP-MS. Further, it was found that almost ~4 cisplatin molecules bound with each B-GNPs nanoparticle.

Differential expression and bioinformatics analysis of circRNA in osteosarcoma

AIM

This research aims to investigate the expression profile of circRNA in osteosarcoma and to identify the underlying pathogenesis core genes of osteosarcoma.Methods: Illumina HiSeq was used to screen differentially expressed circRNAs between the tumour tissues and paracancerous tissues of three osteosarcoma patients. Bioinformatics analysis was used to analyse their potential functions. Five differentially expressed circRNAs were selected to detect the relative expression level in tumour and paracancerous tissues of ten osteosarcoma patients by real-time PCR. The databases such as DisGeNET and miRWalk were used to collect related genes or miRNAs.

RESULTS

A total of 259 differentially expressed circRNAs were evaluated in patients with osteosarcoma, of which 132 were up-regulated and 127 were down-regulated. Compared with that in paracancerous tissues, circ_32279 and circ_24831 were significantly down-regulated while circ_2137 and circ_20403 were significantly up-regulated in osteosarcoma tissues. The differential expression of circRNA is closely linked to biological processes and molecular functions. The difference in circRNA was mainly linked to the 'phosphatidylinositol signalling system' signal pathway and the 'inositol phosphate metabolism' signal pathway.

CONCLUSION

The present study identified a profile of abnormal regulation of circRNA in osteosarcoma. Bioinformatics analysis indicates that the deregulated circRNAs may be related to the occurrence and development of osteosarcoma.

Inter-rater Variability in the Interpretation of Pre and Post Contrast MRI for Pre-Surgical Evaluation of Osteosarcoma in Long Bones in Pediatric Patients and Young Adults

BACKGROUND AND OBJECTIVES

The value of gadolinium enhanced magnetic resonance imaging (MRI) sequences for extremity osteosarcoma resection planning is unverified. We evaluate the performance of intravenous gadolinium enhanced MRI for identification of neurovascular bundle involvement (NBI) and intraarticular extension (IAE) in patients with osteosarcoma.

METHODS

Two pediatric radiologists independently analyzed MRI examinations of patients with pathology proven extremity osteosarcoma for NBI and IAE. Initial evaluation utilized only non-contrast MRI images (PRE) and, after 2 weeks, subsequent evaluation included both the pre and post contrast images (POST). Cohen's Kappa and McNemar's test were calculated to assess agreement between PRE and POST image interpretations of NBI and IAE.

RESULTS

56 patients with 90 preoperative MRI examinations were analyzed. PRE and POST interpretations were rarely discordant; 4/90 cases for NBI (Kappa 0.91) and 2/90 cases for IAE (Kappa 0.95). McNemar's test did not show a difference between PRE and POST imaging (NBI p=0.62; IAE p=0.48).

CONCLUSION

No significant difference between PRE and POST image interpretation was found. A high level of agreement between PRE and POST image interpretation suggests that pre-contrast MRI may be sufficient for pre-surgical planning for pediatric patients with long bone osteosarcoma.

Insights into the roles of miRNAs; miR-193 as one of small molecular silencer in osteosarcoma therapy

Today, cancer is one of the most common causes of death. Osteosarcoma (OS) is a tumor in long bones and its prevalence is high in teenagers and young people. Among the methods that used to treat cancer, one can name chemotherapy, surgery, and radiotherapy. Since these methods have some disadvantages and they are not absolutely successful, the use of microRNAs (miRNAs) is very useful in diagnosis and treatment of OS. MiRNAs are small non-coding RNA molecules, containing 18-25 nucleotides, which are involved in the regulation of gene expression via binding to messenger RNA (mRNA). These RNAs are divided into two classes of suppressors and oncogenes. During OS, there is aberrant expression of several miRNAs. Among these miRNAs are downregulation of miR-193 that has been associated with cancer occurrence. The aim of the current manuscript is to have overview on the treatment approaches of OS with special focus on miR-193.

Genetic polymorphisms of ERCC-1 and ERCC-2 are not prognostic markers in osteosarcoma patients with chemotherapy: A meta-analysis in Chinese population

AIM

To make an accurate estimation of the association of ERCC1 and ERCC2 polymorphisms with osteosarcoma (OS) prognosis in Chinese population.

METHODS

Total 7 qualified studies with 1404 osteosarcoma patients were included. Odds ratios (OR) with 95% CIs were pooled for the survival rate in different osteosarcoma patients with ERCC1 and ERCC2 genetic polymorphisms. The heterogeneity was assessed by I test. Potential publication bias was assessed by Begg funnel plot and Egger linear regression test.

RESULTS

In rs11615, no significant association was found under dominant [TT+TC vs. CC: OR = 1.252, 95% CI:0.864-1.815, P = .235], recessive [TT vs. TC+CC: OR = 0.850, 95% CI: 0.695-1.030, P = .095] or allelic model [T vs. C Allele: OR = 1.219, 95% CI: 0.922-1.612, P = .165]. In rs13181, no significant association was found under dominant [AA+AC vs. CC: OR = 1.031, 95% CI: 0.800-1.329, P = .801], recessive [AA vs. AC+CC: OR = 1.005, 95% CI: 0.875, 1.154, P = .944] or allelic model [A vs. C Allele: OR = 1.009, 95% CI: 0.903-1.128, P = .870]. In rs1799793, no significant association was found under dominant [GG+GA vs. AA: OR = 1.134, 95% CI: 0.884-1.454, P = .322, recessive [GG vs. AG+AA: OR = 1.025, 95% CI: 0.881-1.192, P = .750], or allelic model [G vs. A Allele: OR = 1.046, 95% CI: 0.930-1.177, P = .450].

CONCLUSION

This study did not support rs11615, rs13181 or rs1799793 to be used as surrogate markers for clinical outcome of osteosarcoma with chemotherapy.

Hesperidin exhibits in vitro and in vivo antitumor effects in human osteosarcoma MG-63 cells and xenograft mice models via inhibition of cell migration and invasion, cell cycle arrest and induction of mitochondrial-mediated apoptosis

The objective of the present study was to investigate the anticancer properties of hesperidin against human osteosarcoma MG-63 cells. Its effects on apoptosis, cell migration, cell invasion and cell cycle arrest, and its effects on tumor volume and weight were also evaluated in the present study. MTS assay was used to study the cytotoxic effects of the compound on cell viability. Effects on apoptosis and cell cycle arrest were evaluated by flow cytometry. In vitro wound healing assay and Matrigel assay were performed to study the effects of hesperidin on cell migration and cell invasion, respectively. Hesperidin exerted dose-dependent and time-dependent growth inhibitory effects on cervical cancer cells with IC50 values of 33.5, 23.8 and 17.6 µM, respectively, at 24, 48 and 72 h time intervals. Hesperidin led to early and late apoptosis induction in these cells. Hesperidin-treated cells also led to G2/M phase cell cycle arrest, which exhibited strong dose-dependence. Hesperidin treatment also led to inhibition of cell migration and invasion.

Silencing of cytoskeleton-associated protein 2 represses cell proliferation and induces cell cycle arrest and cell apoptosis in osteosarcoma cells

Osteosarcoma is the most common primary bone malignancy, mainly occurring in children and adolescents. Cytoskeleton-associated protein 2 (CKAP2), which plays important roles in cell proliferation, has been reported to be overexpressed in diverse human cancers. In the present study, we aimed at exploring the expression and functions of CKAP2 in osteosarcoma. The mRNA and protein expression of CKAP2 was analyzed on collected osteosarcoma and control bone cyst tissues. The results indicated that CKAP2 expression was remarkably elevated in osteosarcoma tissues compared with bone cysts tissues. The expression level of CKAP2 in osteosarcoma was associated with overall survival, tumor size and tumor stage. In addition, down-regulation of CKAP2 by RNA interference in osteosarcoma cell lines, MG63 and SW1353, caused a remarkable inhibition in cell proliferation in vitro and xenograft growth in nude mice. Silencing of CKAP2 also significantly induced G0/G1 arrest and cell apoptosis of osteosarcoma cells. Furthermore, phosphorylation levels of Janus kinase 2 (JAK2) and Signal transducers and activators of transcription 3 (STAT3) were significantly reduced in CKAP2 knockdown cells. The expression of downstream targets of JAK2/STAT3 signaling, Cyclin D1, Bcl-2 and survivin, was also decreased in CKAP2 knockdown cells. Such aberrations can be rescued by re-expression of RNAi-resistant CKAP2. Collectively, the present study indicates that CKAP2 is a potential oncogene by targeting JAK2/STAT3 signaling, and that CKAP2 may serve as a novel target for osteosarcoma therapy.

Inhibition of LCMR1 and ATG12 by demethylation-activated miR-570-3p is involved in the anti-metastasis effects of metformin on human osteosarcoma

Epidemiological studies have demonstrated that metformin could mitigate the progression of several tumors. Although it has been proved that metformin could cause demethylation of DNA and lead to up-regulation of some encoding genes and non-coding RNAs, there is little data about the effects of metformin on metastasis, and the interaction between metastasis and autophagy in human osteosarcoma cells. Here, we found miR-570-3p was significantly down-regulated in human metastatic osteosarcoma tissues but not in non-metastatic osteosarcoma tissues. Metformin attenuates the metastasis and autophagy in osteosarcoma. Interestingly, this autophagy favors osteosarcoma cells invasion. Moreover, reduction of metformin-induced inhibition of autophagy could reverse the invasion suppression in osteosarcoma. Mechanistically, metformin increases miR-570-3p by the demethylation of DNA, and the upregulation of miR-570-3p repressed the translation of its target, LCMR1 and ATG12. Our results, for the first time, presents evidence that the miR-570-3p-mediated suppression of LCMR1 and ATG12 is involved in the metformin-induced inhibition of metastasis in osteosarcoma cells.

Overexpression of p62 is associated with poor prognosis and aggressive phenotypes in osteosarcoma

p62 (also known as sequestosome 1) protein, is a small regulatory protein that accumulates in autophagy-defective cells that has been demonstrated to be involved in the prognosis and survival of patients with several types of cancer. However, to the best of our knowledge, there have been no such studies for osteosarcoma (OS). In the present study, the expression of p62 in 70 OS samples was determined using immunohistochemistry and its association with various clinicopathological factors was assessed. The results demonstrated that the overexpression of p62 protein was detected in 77.1% (54/70) samples, and the expression levels were significantly associated with tumor size (P=0.001), metastasis (P=0.036), clinical staging (P=0.003) and poor prognosis (P=0.0058). Furthermore, suppression of the p62 expression by short hairpin RNA interference in F5M2 and F4 cells lines led to decreased cell proliferation, migration and invasion in vitro. These results suggested that increased expression of p62 may be involved in OS progression, and therefore the excess expression of p62 may serve as a novel prognostic biomarker for patients with OS.

MicroRNA-192 inhibits the proliferation, migration and invasion of osteosarcoma cells and promotes apoptosis by targeting matrix metalloproteinase-11

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression during stem cell growth, proliferation and differentiation. miRNAs are also involved in the development and progression of a number of cancer types, including osteosarcoma (OS). miR-192 is significantly downregulated in various tumors, including lung, bladder and rectal cancer. miR-192 expression is associated with the migration and invasion of OS cells. However, the expression of miR-192 and its effects on the development of OS have not been reported. In the present study, the involvement of miR-192 and its molecular mechanisms in the development of OS was investigated. The results indicate that miR-192 expression was significantly downregulated in OS tissues compared with non-tumor tissues (P<0.05). Next, a miR-192 agomir was transfected into the OS cell line MG-63 to upregulate miR-192. The effects of miR-192 overexpression were then investigated by examining cell proliferation, apoptosis, migration and invasion. Matrix metalloproteinase (MMP)-11 belongs to a family of nine or more highly homologous Zn²⁺-endopeptidases. It was demonstrated that the mRNA and protein expression of MMP-11 were upregulated in OS tissues compared with non-tumor tissues (P<0.05). MMP-11 was predicted by TargetScan and miRanda as a miR-192 target, which was confirmed by western blotting and dual-luciferase assays. Finally, it was demonstrated that the overexpression of miR-192 was able to downregulate MMP-11 expression and reduce proliferation, migration and invasion, and promote apoptosis in OS cells. Together, these data indicate that miR-192 may be a tumor suppressor that inhibits the progression and invasion of OS by targeting MMP-11. Therefore, miR-192 may be useful for the diagnosis and treatment of OS.

Primary Osteosarcoma in the Elderly Revisited: Current Concepts in Diagnosis and Treatment

PURPOSE OF REVIEW

Osteosarcoma is mostly seen in bones of children and young adults. When it occurs in older persons, the tumor is considered secondary usually complicating Paget disease or irradiated bone. However, there is a second incidence peak of primary osteosarcoma later in life when these tumors occur de novo. This article describes the clinical, imaging, and treatment of POS in older patients, including demographic data of patients from our institution.

FINDINGS

We present our experience with 920 cases of osteosarcoma that were seen between 1984 and 2003 at the University of Texas MD Anderson Cancer Center in Houston, TX, USA. Among the 868 primary osteosarcoma of bones, there were 100 (11.52%), which comprised 69% of the tumors in patients over the age of 50 years. Older patients with primary osteosarcoma tend to have relatively more common axial skeleton involvement, have more distant disease, and are difficult to treat because of concomitant comorbidities. Despite that, most adult patients treated with chemotherapy have shown good results with longer disease-free survival. A lytic bone lesion seen in radiographs of elderly patients should include primary osteosarcoma among differential diagnoses. Radical surgery and chemotherapy seem to ensure long-term disease-free survival in most cases. The elderly patients with POS in pelvis, spine, and upper extremities and those with distant disease (metastases) have worse prognosis.

Downregulation of SOX3 leads to the inhibition of the proliferation, migration and invasion of osteosarcoma cells

Sex determining region Y-box protein 3 (SOX3) is involved in embryonic development and tumorigenesis. However, the expression and precise role of SOX3 in osteosarcoma remain unclear. In this study, we reported that SOX3 expression was upregulated in osteosarcoma tissues compared with non-cancerous bone cyst tissues. To elucidate the cellular and molecular function of SOX3, we examined the consequences of SOX3 knockdown in osteosarcoma cells. We found that the downregulation of SOX3 inhibited the proliferation, migration and invasion of osteosarcoma cells. SOX3 downregulation also increased the cell population in the G1 phase and induced cell apoptosis. SOX3 knockdown-mediated cell cycle arrest and cell apoptosis were associated with decreased levels of Cdc25A, cyclin D1, proliferating cell nuclear antigen (PCNA) and Bcl-2, as well as an increased Bax expression. We also found that the downregulation of SOX3 decreased the expression of Snail, Twist and matrix metalloproteinase-9 (MMP-9), and increased E-cadherin expression, resulting in the inhibition of cell migration and invasion. Taken together, our data indicate that SOX3 may serve as an oncogene in osteosarcoma, and SOX3 downregulation may prove to be a novel approach for the inhibition of osteosarcoma progression.

MicroRNA-567 inhibits cell proliferation, migration and invasion by targeting FGF5 in osteosarcoma

MicroRNAs (miRNAs) have been widely reported to have important regulatory roles in various human tumors, including osteosarcoma (OS). The aim of this study was to focus on the role of less well-known miRNA-567 (miR-567) in OS. We found the expression of miR-567 was significantly reduced in OS tissues and cell lines (MG-63, U2OS and Saos-2) compared with the adjacent normal tissues and normal osteoblastic cells (hFOB), respectively. Moreover, exogenous miR-567 overexpression inhibited OS cell proliferation, migration and invasion by CCK-8, Transwell assays, respectively. We further explored the mechanism underlying the suppressive effects of miR-567 on OS cells and identified a potential target of miR-567 binds to the 3'UTR of fibroblast growth factor 5 (FGF5) using TargetScan program. Furthermore, enforced expression of miR-567 decreased the expression of FGF5 in both MG-63 and U2OS cells using luciferase reporter assay and Western blotting. We also showed that overexpression of FGF5 could partially antagonize the suppressive effects of miR-567 on OS cell proliferation, migration and invasion. Taken together, our data indicated that miR-567 may function as a tumor suppressor by negatively regulating FGF5 and be potential therapeutic targets for the treatment of OS.

MiR-564 is down-regulated in osteosarcoma and inhibits the proliferation of osteosarcoma cells via targeting Akt

Aberrant expression of miRNAs has been observed in a variety of human cancers. In this study, we reported that miR-564 was down-regulated in human osteosarcoma (OS) cell lines and patients. Overexpression of miR-564 in OS cells suppressed the cell proliferation and induced cell apoptosis. Mechanistically, we identified Akt as a direct target of miR-564. Highly expressed miR-564 decreased the expression of Akt at both mRNA and protein level and consequently, inhibited the essential role of Akt in the glycolysis of OS cells. Notably, restoring the expression of Akt in miR-564 overexpressing cells recovered the glucose metabolism and cell growth. These results suggested that miR-564 inhibited the glycolysis and cell proliferation through directly targeting Akt, which highlighted the potential application of miR-564-Akt axis in the treatment of osteosarcoma.

miR‑328‑3p enhances the radiosensitivity of osteosarcoma and regulates apoptosis and cell viability via H2AX

Osteosarcoma is a kind of high-risk sarcoma of the skeleton typically observed in people under 25 years old. Currently, radiotherapy is widely applied in cancer treatment. However, osteosarcoma is radioresistant and accordingly new, more effective radiosensitizers are needed. miRNAs have been reported to play an important role in osteosarcoma radiosensitivity. We examined the modulating effect of miR-328-3p in vivo and in vitro. miR-328-3p was downregulated in HOS-2R cells. The overexpression of miR-328-3p enhanced the radiosensitivity of osteosarcoma cells. miR-328-3p inhibited proliferation and promoted apoptosis in osteosarcoma cells under radiation conditions. In cells overexpressing miR-328-3p, H2AX expression was downregulated. We found that miR-328-3p targets H2AX and inhibits its expression. It was concluded, that miR-328-3p enhances the radiosensitization of osteosarcoma following X-ray irradiation, and determined that it directly targets H2AX to regulate radiosensitization.

An EGFR and AKT Signaling Pathway was Identified with Mediation Model in Osteosarcomas Clinical Study

Identification of correlation pattern and signal pathway among biomarkers in patients has become increasingly interesting for its potential values in diagnosis, treatment and prognosis. EGFR and p-AKT signaling in osteosarcoma (OS) patients were analyzed for its relationship with cancer cell proliferation maker, Ki-67, using causal procedures and statistical tests. A total of 69 patients were collected who present to Vanderbilt University Medical Center with newly diagnosed, previously untreated osteosarcomas during the clinical study period 1994 through 2003. Tissue microarrays were constructed for EGFR, p-AKT and Ki-67. The mediation model was constructed with structural equation model (SEM) for the causal analysis of the three biomarkers in osteosarcoma patients. The results suggested a mediating effect of p-AKT for the causal relationship between EGFR and Ki-67. The study also found significant associations between EGFR and Ki-67 (p = 0.002), EGFR and p-AKT (p = 0.027), and p-AKT and Ki-67 controlling EGFR (p = 0.004). After the impact of EGFR on Ki-67 was accounted for by p-AKT, the relation between EGFR and Ki-67 was no longer significant (p = 0.381). The mediating effect was confirmed with Sobel test (p < 0.001) and Goodman (I) test (p < 0.001). The study indicated that a mediation model could be an approach to exploring the correlation pattern of EGFR and AKT signal pathway for cancer cell proliferation in OS patients in clinical study.

Interleukin-6 upregulates SOX18 expression in osteosarcoma

Aim

SOX18 is a potential oncogene in osteosarcoma via controlling osteosarcoma cell proliferation and metastasis. Interleukin-6 (IL-6), a major activator of Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) signaling, plays an important role in the growth of carcinoma cells. The present study aims to investigate the correlation between IL-6 and SOX18 in osteosarcoma.

Materials and methods

Protein expression and mRNA expression were determined by Western blot and real-time polymerase chain reaction (PCR) analysis, respectively. Cell proliferation and apoptosis were identified by Cell Counting Kit-8 assay and flow cytometry analysis, respectively.

Results

We found that SOX18, IL-6 and p-STAT3 were elevated in osteosarcoma compared with bone cyst tissues. A positive correlation between the mRNA levels of IL-6 and SOX18 was observed in osteosarcoma tissues. IL-6 stimulation dose dependently induced the mRNA and protein levels of SOX18 in U-2OS and MG63 cells. Furthermore, IL-6 significantly rescued the inhibitory and induction effects of SOX18 knockdown on osteosarcoma cell proliferation and apoptosis, respectively. The changes in cell proliferation (PCNA) and apoptosis-related proteins (Bcl-2, Bax and Cleaved-Caspase 3) were in line with the results of cell proliferation and apoptosis assays.

Conclusion

Our data suggest that IL-6 is a possible upstream regulator for SOX18 in osteosarcoma.

In vivo pharmacological evaluation and efficacy study of methotrexate-encapsulated polymer-coated layered double hydroxide nanoparticles for possible application in the treatment of osteosarcoma

Considering the existing drawbacks of methotrexate (MTX) with respect to its solubility and toxicity, we incorporated it in a nanoceramic matrix, Mg-Al-layered double hydroxide (LDH) to form LDH-MTX nanoparticles, and the same was in turn encapsulated in a nontoxic and biodegradable polymer, poly (D,L-lactide-co-glycolide) (PLGA), to arrest the initial burst release and dose-dumping-related toxicity, already reported by our group. Our present study was designed to evaluate the pharmacokinetics, tissue distribution, survival rate of the test animals, and antitumor efficacy of the PLGA-LDH-MTX nanoparticles and its counterpart without LDH, PLGA-MTX nanoparticles compared with bare MTX. The median lethal dose (LD₅₀) of the former was higher, compared with bare MTX, using Balb/c nude mice, indicating it to be completely safe for use. Also, a comparative pharmacokinetic and antitumour efficacy study using MTX, PLGA-MTX, and PLGA-LDH-MTX nanoparticles in osteosarcoma-induced Balb/c nude mice in vivo demonstrated superiority of PLGA-LDH-MTX as compared to PLGA-MTX and bare MTX. The results suggest that PLGA-LDH-MTX nanoparticles might exhibit potential advantages over the present-day chemotherapy over bare MTX, for the possibility of treatment of osteosarcoma.

Long noncoding RNA MALAT1 promotes cell proliferation through suppressing miR-205 and promoting SMAD4 expression in osteosarcoma

Increasing evidences have indicated that long non-coding RNAs (lncRNAs) play an important role in multiply biological processes including cell development, differentiation, proliferation and invasion. The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), is a highly conserved nuclear ncRNA and a key regulator of metastasis development in several cancers. However, its role in osteosarcoma progression is not well known. In this study, we sought to determine the clinical and bilogical role of MALAT1 in osteosarcoma progression. RT-qPCR analysis showed that MALAT1 expression was significantly increased in primary osteosarcoma tissues and cell lines. Kaplan-Meier analysis indicated that patients with high expression of MALAT1 was associated with poor overall survival compared with the low expressing patients. Furthermore, the gain and loss function assay showed that miR-205 was suppressed by MALAT1 in osteosarcoma and this interaction between miR-205 and MALAT1 has reciprocal effects. Cell viability assay showed that MALAT1 promoted MG-63 and SAOS-2 cell growth through suppressing miR-205. Subsequently, the downstream gene SMAD4 was identified as a direct functional target of miR-205, and miR-205 suppressed osteosarcoma cell growth through suppressing SMAD4. Finally, we demonstrated that MALAT1 promoted osteosarcoma progression via a miR-205-SMAD4 axis. In conclusion, we revealed that enhanced MALAT1 expression predicted unfavourable outcome in osteosarcoma and promoted cell proliferation through suppressing miR-205 and activating SMAD4 function. Thus, lncRNA MALAT1 may serve as a promising prognostic and therapeutic target for osteosarcoma patients.

LncRNA-ANCR regulates the cell growth of osteosarcoma by interacting with EZH2 and affecting the expression of p21 and p27

Background

Osteosarcoma (OS) is one of the most common malignant tumors developed in the bone. EZH2 has been found to play pivotal roles in the development of various cancers. LncRNA-ANCR (anti-differentiation ncRNA) has been reported to interact with EZH2 and regulated osteoblast differentiation. Our study aimed to investigate the effect of lncRNA-ANCR on the tumorigenesis of osteosarcoma and explore the underlying molecular mechanism.

Methods

RT-PCR was performed to detect the messenger RNA (mRNA) levels of lncRNA-ANCR, EZH2, p21, and p27 in OS tissues and cell lines. The cell proliferation, transwell invasion, and migration assays were conducted to evaluate the influence of lncRNA-ANCR depletion on the growth of OS cells. RNA pull-down assay was carried out to detect the interaction between lncRNA-ANCR and EZH2. Correlation between the expression of lncRNA-ANCR and the expression of EZH2 were analyzed by cross-tabulation.

Results

LncRNA-ANCR is highly expressed in both OS tissues and cell lines. Reduced expression of lncRNA-ANCR inhibited the cell proliferation, invasion, and migration of OS cells. The cell apoptosis rate was also increased with the overexpression of lncRNA-ANCR. Mechanistically, downregulation of lncRNA-ANCR reduced the mRNA level of EZH2 and increased the expression of p21 and p27 at both mRNA and protein levels. LncRNA-ANCR interacted with EZH2 and their expression abundance was positively correlated in OS patients.

Conclusion

LncRNA-ANCR inhibited the cell proliferation, migration, and invasion of OS cells possibly through interacting with EZH2 and regulating the expression of p21 and p27.

MicroRNA-25 suppresses proliferation, migration, and invasion of osteosarcoma by targeting SOX4

Altered expression of the miR-25 has been implicated in many human malignant progression as oncogene or tumor suppressor. However, the precise role of miR-25 in osteosarcoma progression remains largely unclear. This study aimed to investigate the role and underlying mechanism of miR-25 in osteosarcoma. In this study, we demonstrated that miR-25 was significantly downregulated in osteosarcoma cell lines and tissues and that lower miR-25 was associated with advanced tumor-node-metastasis stage and lymph node metastasis. Then, we found that introduction of miR-25 significantly suppressed the proliferation, colony formation, migration, and invasion of osteosarcoma cells in vitro and retarded tumor growth in vivo. Further studies indicated that the epithelial-mesenchymal transition-related transcription factor, SOX4 (SRY-related high-mobility group box 4), was a direct target gene of miR-25, evidenced by bioinformatics analysis predicted and luciferase reporter assay. Furthermore, miR-25 could decrease the expression of SOX4 levels and inhibited epithelial-mesenchymal transition process. The levels of miR-25 were inversely correlated with those of SOX4 expression in osteosarcoma tissues. SOX4 overexpression rescued miR-25-induced suppression of proliferation, migration, and invasion of osteosarcoma cells. Taken together, these results suggest that miR-25 functions as a tumor suppressor in the progression of osteosarcoma by repressing SOX4.

Increased circular RNA UBAP2 acts as a sponge of miR-143 to promote osteosarcoma progression

Deregulated expression of circular RNA (circRNA) has been determined to be important in carcinogenesis and progression; however, in the most common type of primary malignant bone tumor osteosarcoma, the roles of circRNA in cancer development still remain to be elucidated. Here, we found that circRNA UBAP2 (circUBAP2) expression is significantly increased in human osteosarcoma tissues as compared to those in matched controls. Increased circUBAP2 expression was significantly correlated with human osteosarcoma progression and prognosis. Furthermore, increased circUBAP2 could promote osteosarcoma growth and inhibit apoptosis both in vitro and in vivo. Mechanistically, circUBAP2 was found to inhibit the expression of microRNA-143 (miR-143), thus enhancing the expression and function of anti-apoptotic Bcl-2, which is a direct target of miR-143. Together, our results suggest the roles of circUBAP2 in osteosarcoma development and implicate its potential in prognosis prediction and cancer therapy.