Methotrexate, doxorubicin, and cisplatinum regimen is still the preferred option for osteosarcoma chemotherapy: A meta-analysis and clinical observation

Vibrational microspectroscopy as a tool to unveil new chemotherapeutic strategies against osteosarcoma

Over the years, osteosarcoma therapy has had a significative improvement with the use of a multidrug regime strategy, increasing the survival rates from less than 20 % to circa 70 %. Different types of development of new antineoplastic agents are critical to achieve irreversible damage to cancer cells, while preserving the integrity of their healthy counterparts. In the present study, complexes with two and three Pd(II) centres linked by the biogenic polyamines: spermine (Pd2SpmCl4) and spermidine (Pd3Spd2Cl6) were tested against non-malignant (osteoblasts, HOb) and cancer (osteosarcoma, MG-63) human cell lines. Either alone or in combination according to the EURAMOS-1 protocol, they were used versus cisplatin as a drug reference. By evaluating the cytotoxic effects of both therapeutic approaches (single and drug combination) in HOb and MG-63 cell lines, the selective anti-tumoral potential is assessed. To understand the different treatments at a molecular level, Synchrotron Radiation Fourier Transform Infrared and Raman microspectroscopies were applied. Principal component analysis and hierarchical cluster analysis are applied to the vibrational data, revealing the major metabolic changes caused by each drug, which were found to rely on DNA, lipids, and proteins, acting as biomarkers of drug-to-cell impact. The main changes were observed for the B-DNA native conformation to either Z-DNA (higher in the presence of polynuclear complexes) or A-DNA (preferably after cisplatin exposure). Additionally, a higher effect upon variation in proteins content was detected in drug combination when compared to single drug administration proving the efficacy of the EURAMOS-1 protocol with the new drugs tested.

Correlation of High-Grade Osteosarcoma Response to Chemotherapy with Enhanced Tissue Immunological Response: Analysis of CD95R, IFN-γ, Catalase, Hsp70, and VEGF

High-grade osteosarcoma, a primary malignant bone tumour, is experiencing a global increase in reported incidence with varied prevalence. Despite advances in management, which include surgery and neoadjuvant chemotherapy often an unsatisfactory outcome is found due to poor or heterogeneous response to chemotherapy. Our study delved into chemotherapy responses in osteosarcoma patients and associated molecular expressions, focusing on CD95 receptor (CD95R), interferon (IFN)-γ, catalase, heat-shock protein (Hsp)70, and vascular endothelial growth factor (VEGF). Employing immunohistochemistry and Huvos grading of post-chemo specimens, we analysed formalin-fixed paraffin-embedded (FFPE) osteosarcoma tissue of resected post-chemotherapy specimens from Dr. Soetomo General Academic Hospital in Surabaya, Indonesia (DSGAH), spanning from 2016 to 2020. Results revealed varied responses (poor 40.38%, moderate 48.08%, good 11.54%) and distinct patterns in CD95R, IFN-γ, catalase, Hsp70, and VEGF expression. Significant differences among response groups were observed in CD95R and IFN-γ expression in tumour-infiltrating lymphocytes. The trend of diminishing CD95R expression from poor to good responses, accompanied by an increase in IFN-γ, implied a reduction in the count of viable osteosarcoma cells with the progression of Huvos grading. Catalase expression in osteosarcoma cells was consistently elevated in the poor response group, while Hsp70 expression was highest. VEGF expression in macrophages was significantly higher in the good response group. In conclusion, this study enhances our understanding of immune-chemotherapy interactions in osteosarcoma and identifies potential biomarkers for targeted interventions.

Niclosamide: A career builder

My contribution to honoring Professor Kinam Park celebrates and resonates with his scholarly career in drug delivery, his commitment to encouraging the next generation(s), and his efforts to keep us focused on clinically effective formulations. To do this I take as my example, niclosamide, a small molecule protonophore that, uniquely, can "target" all cell membranes, both plasma and organelle. As such, it acts upstream of many cell pathways and so has the potential to affect many of the essential events that a cell, and particularly a diseased cell or other entities like a virus, use to stay alive and prosper. Literature shows that it has so far been discovered to positively influence (at least): cancer, bacterial and viral infection, metabolic diseases such as Type II diabetes, NASH and NAFLD, artery constriction, endometriosis, neuropathic pain, rheumatoid arthritis, sclerodermatous graft-versus-host disease, systemic sclerosis, Parkinson's, and COPD. With such a fundamental action and broad-spectrum activity, I believe that studying niclosamide in all its manifestations, discovering if and to what extent it can contribute positively to disease control (and also where it can't), formulating it as effective therapeutics, and testing them in preclinical and clinical trials is a career builder for our next generation(s). The article is divided into two parts: Part I introduces niclosamide and other proton shunts mainly in cancer and viral infections and reviews an exponentially growing literature with some concepts and physicochemical properties that lead to its proton shunt mechanism. Part II focuses on repurposing by reformulation of niclosamide. I give two examples of "carrier-free formulations", - one for cancer (as a prodrug therapeutic of niclosamide stearate for i.v. and other administration routes, exemplified by our recent work on Osteosarcoma in mice and canine patients), and the other as a niclosamide solution formulation (that could provide the basis for a preventative nasal spray and early treatment option for COVID19 and other respiratory virus infections). My goal is to excite and enthuse, encourage, and motivate all involved in the drug development and testing process in academia, institutes, and industry, to learn more about this interesting molecule and others like it. To enable such endeavors, I give many proposed ideas throughout the document, that have been stimulated and inspired by gaps in the literature, urgent needs in disease, and new studies arising from our own work. The hope is that, by reading through this document and studying the suggested topics and references, the drug delivery and development community will continue our lineage and benefit from our legacy to achieve niclosamide's potential as an effective contributor to the treatment and control of many diseases and conditions.

Dual targeting Bcl-2 and Bcl-xL augments osteosarcoma response to doxorubicin

Chemotherapy resistance is the major cause of treatment failure in osteosarcoma, the most common primary bone malignancy, and sensitizing therapeutic strategy is required to improve the clinical outcome. In this study, we discovered that navitoclax, a selective inhibitor of Bcl-2/Bcl-xL, effectively combats chemoresistance in osteosarcoma. Our research revealed that Bcl-2, but not Bcl-xL, is upregulated in osteosarcoma cells that are resistant to doxorubicin. However, venetoclax, a specific inhibitor of Bcl-2, did not exhibit activity against doxorubicin-resistant cells. Further analysis showed that depleting either Bcl-2 or Bcl-xL alone was insufficient to overcome doxorubicin resistance. Only by depleting both Bcl-2 and Bcl-xL significantly reduce the viability of doxorubicin-resistant cells. Similarly, navitoclax not only decreased the viability of doxorubicin-resistant cells but also acted synergistically with doxorubicin in cells sensitive to the drug. To confirm the ability of navitoclax to overcome doxorubicin resistance, we conducted experiments using multiple mouse models of osteosarcoma, both doxorubicin-sensitive and doxorubicin-resistant. The results provided confirmation that navitoclax is effective in overcoming doxorubicin resistance. Our findings demonstrate that simultaneous inhibition of Bcl-2 and Bcl-xL could serve as a novel strategy to sensitize chemoresistant osteosarcoma cells. Moreover, our study presents preclinical evidence supporting the potential of a navitoclax and doxorubicin combination therapy for the treatment of osteosarcoma, paving the way for future clinical investigations.

5-Hydroxytryptophan acts as a gap junction inhibitor to limit the spread of chemotherapy-induced cardiomyocyte injury and mitochondrial dysfunction

Anthracycline chemotherapeutics like doxorubicin (DOX) are widely used against various cancers but are accompanied by severe cardiotoxic effects that can lead to heart failure. Through whole transcriptome sequencing and pathological tissue analysis in a murine model, our study has revealed that DOX impairs collagen expression in the early phase, causing extracellular matrix anomalies that weaken the mechanical integrity of the heart. This results in ventricular wall thinning and dilation, exacerbating cardiac dysfunction. In this work, we have identified 5-hydroxytryptophan (5-HTP) as a potent inhibitor of gap junction communication. This inhibition is key to limiting the spread of DOX-induced cardiotoxicity. Treatment with 5-HTP effectively countered the adverse effects of DOX on the heart, preserving ventricular structure and ejection fraction. Moreover, 5-HTP enhanced mitochondrial respiratory function, as shown by the O2k mitochondrial function assay, by improving mitochondrial complex activity and ATP production. Importantly, the cardioprotective benefits of 5-HTP did not interfere with DOX's ability to combat cancer. These findings shed light on the cardiotoxic mechanisms of DOX and suggest that 5-HTP could be a viable strategy to prevent heart damage during chemotherapy, offering a foundation for future clinical development. This research opens the door for 5-HTP to be considered a dual-purpose agent that can protect the heart without compromising the oncological efficacy of anthracycline chemotherapy.

Cytotoxicity Enhancement in Osteosarcoma with Multifunctional I-131 Radiotherapeutic Nanoparticles: In Vitro Three-Dimensional Spheroid Model and Release Kinetics Modeling

This novel radiolabeled chitosan nanoparticle, facilitated with curcumin, increased doxorubicin cytotoxicity and radiosensitivity to MG-63 osteosarcoma cells in a three-dimensional model. Delivery of the anti-epidermal growth factor receptor (EGFR) targeted carboxymethyl chitosan nanoparticles, directly labeled with Na131I (ICED-N), achieved deep tumor penetration in a three-dimensional model. Of three kinetic models, the Higuchi model more closely matched the experimental curve and release profiles. The anti-EGFR targeting resulted in a 513-fold greater targeting efficacy to MG-63 (EGFR+) cells than the control fibroblast (EGFR-) cells. The curcumin-enhanced ICED-N (4 × 0.925 MBq) fractionated-dose regime achieved an 18.3-fold increase in cell cytotoxicity compared to the single-dose (1 × 3.70 MBq) doxorubicin-loaded nanoparticle, and a 13.6-fold increase in cell cytotoxicity compared to the single-dose Na131I nanoparticle. Moreover, the ICED-N fractionated dose increased cells in the G2/M phase 8.78-fold, indicating the cell cycle arrest in the G2/M phase is associated with DNA fragmentation, and the intracellular damage is unable to be repaired. Overall, the results indicate that the fractionated dose was more efficacious than a single dose, and curcumin substantially increased doxorubicin cytotoxicity and amplified osteosarcoma cell radiosensitivity to Na131I.

A CRISPR-drug perturbational map for identifying compounds to combine with commonly used chemotherapeutics

Combination chemotherapy is crucial for successfully treating cancer. However, the enormous number of possible drug combinations means discovering safe and effective combinations remains a significant challenge. To improve this process, we conduct large-scale targeted CRISPR knockout screens in drug-treated cells, creating a genetic map of druggable genes that sensitize cells to commonly used chemotherapeutics. We prioritize neuroblastoma, the most common extracranial pediatric solid tumor, where ~50% of high-risk patients do not survive. Our screen examines all druggable gene knockouts in 18 cell lines (10 neuroblastoma, 8 others) treated with 8 widely used drugs, resulting in 94,320 unique combination-cell line perturbations, which is comparable to the largest existing drug combination screens. Using dense drug-drug rescreening, we find that the top CRISPR-nominated drug combinations are more synergistic than standard-of-care combinations, suggesting existing combinations could be improved. As proof of principle, we discover that inhibition of PRKDC, a component of the non-homologous end-joining pathway, sensitizes high-risk neuroblastoma cells to the standard-of-care drug doxorubicin in vitro and in vivo using patient-derived xenograft (PDX) models. Our findings provide a valuable resource and demonstrate the feasibility of using targeted CRISPR knockout to discover combinations with common chemotherapeutics, a methodology with application across all cancers.

Enhancement of the therapeutic efficacy of the MAP regimen using thiamine pyrophosphate-decorated albumin nanoclusters in osteosarcoma treatment

Recent studies on osteosarcoma regimens have mainly focused on modifying the combination of antineoplastic agents rather than enhancing the therapeutic efficacy of each component. Here, an albumin nanocluster (NC)-assisted methotrexate (MTX), doxorubicin (DOX), and cisplatin (MAP) regimen with improved antitumor efficacy is presented. Human serum albumin (HSA) is decorated with thiamine pyrophosphate (TPP) to increase the affinity to the bone tumor microenvironment (TME). MTX or DOX (hydrophobic MAP components) is adsorbed to HSA-TPP via hydrophobic interactions. MTX- or DOX-adsorbed HSA-TPP NCs exhibit 20.8- and 1.64-fold higher binding affinity to hydroxyapatite, respectively, than corresponding HSA NCs, suggesting improved targeting ability to the bone TME via TPP decoration. A modified MAP regimen consisting of MTX- or DOX-adsorbed HSA-TPP NCs and free cisplatin displays a higher synergistic anticancer effect in HOS/MNNG human osteosarcoma cells than conventional MAP. TPP-decorated NCs show 1.53-fold higher tumor accumulation than unmodified NCs in an orthotopic osteosarcoma mouse model, indicating increased bone tumor distribution. As a result, the modified regimen more significantly suppresses tumor growth in vivo than solution-based conventional MAP, suggesting that HSA-TPP NC-assisted MAP may be a promising strategy for osteosarcoma treatment.

Oxidative stress induction by narasin augments doxorubicin's efficacy in osteosarcoma

Complications and fata toxicity induced by chemotherapy are the main challenge for clinical management of osteosarcoma. The identification of agents that can augment the efficacy of chemotherapy at lower doses may represent an alternative therapeutic strategy. Narasin is a polyether antibiotic widely used in veterinary medicine. In this study, we show that narasin is active against osteosarcoma cells at the same concentrations that are less toxic to normal cells. This effect is achieved by growth inhibition and apoptosis induction, which is mediated by oxidative stress and damage, and mitochondrial dysfunction. The antioxidant N-acetyl-l-cysteine (NAC) abolishes the anti-osteosarcoma activity. Importantly, narasin significantly augments doxorubicin's efficacy in both osteosarcoma cell culturing system and subcutaneous implantation mouse model. The combination of narasin and doxorubicin at non-toxic doses completely arrests osteosarcoma growth in mice. Our results suggest that the concurrent administration of doxorubicin and narasin could present a viable alternative therapeutic approach for osteosarcoma.

Cardiac osteosarcoma: a case report and literature review

Background

Primary cardiac tumors are rare, and malignant primary cardiac tumors are even rarer. Cardiac osteosarcoma is a very rare type of malignant primary cardiac tumor with limited reported cases. We present a case report of cardiac osteosarcoma and review its characteristics and the related literature.

Case summary

A 44-year-old female patient without a specific medical history presented with intermittent dyspnea that started 1 month prior to presentation. A heterogeneous mass was observed in the left atrium on echocardiography and a large mass was observed in the left atrium on computed tomography. Surgery was performed under the suspicion of atypical cardiac myxoma, and the tumor was successfully removed. However, postoperative histopathological examination revealed cardiac osteosarcoma. The patient underwent chemotherapy and has been well maintained without recurrence for 10 years.

Conclusion

We present a case report of the echocardiographic features and treatment strategies for cardiac osteosarcoma, an extremely rare cardiac tumor. Multimodal imaging can be helpful; however, a histological diagnosis through surgical resection is essential. Appropriate treatment and follow-up based on histological findings are necessary.

PLGA-based drug delivery systems in treating bone tumors

Bone tumor has become a common disease that endangers human health. Surgical resection of bone tumors not only causes biomechanical defects of bone but also destroys the continuity and integrity of bone and cannot completely remove the local tumor cells. The remaining tumor cells in the lesion bring a hidden danger of local recurrence. To improve the chemotherapeutic effect and effectively clear tumor cells, traditional systemic chemotherapy often requires higher doses, and high doses of chemotherapeutic drugs inevitably cause a series of systemic toxic side effects, often intolerable to patients. PLGA-based drug delivery systems, such as nano delivery systems and scaffold-based local delivery systems, can help eliminate tumors and promote bone regeneration and therefore have more significant potential for application in bone tumor treatment. In this review, we summarize the research progress of PLGA nano drug delivery systems and PLGA scaffold-based local delivery systems in bone tumor treatment applications, expecting to provide a theoretical basis for developing novel bone tumor treatment strategies.

Targeting strategies for bone diseases: signaling pathways and clinical studies

Since the proposal of Paul Ehrlich's magic bullet concept over 100 years ago, tremendous advances have occurred in targeted therapy. From the initial selective antibody, antitoxin to targeted drug delivery that emerged in the past decades, more precise therapeutic efficacy is realized in specific pathological sites of clinical diseases. As a highly pyknotic mineralized tissue with lessened blood flow, bone is characterized by a complex remodeling and homeostatic regulation mechanism, which makes drug therapy for skeletal diseases more challenging than other tissues. Bone-targeted therapy has been considered a promising therapeutic approach for handling such drawbacks. With the deepening understanding of bone biology, improvements in some established bone-targeted drugs and novel therapeutic targets for drugs and deliveries have emerged on the horizon. In this review, we provide a panoramic summary of recent advances in therapeutic strategies based on bone targeting. We highlight targeting strategies based on bone structure and remodeling biology. For bone-targeted therapeutic agents, in addition to improvements of the classic denosumab, romosozumab, and PTH1R ligands, potential regulation of the remodeling process targeting other key membrane expressions, cellular crosstalk, and gene expression, of all bone cells has been exploited. For bone-targeted drug delivery, different delivery strategies targeting bone matrix, bone marrow, and specific bone cells are summarized with a comparison between different targeting ligands. Ultimately, this review will summarize recent advances in the clinical translation of bone-targeted therapies and provide a perspective on the challenges for the application of bone-targeted therapy in the clinic and future trends in this area.

Baicalin induces ferroptosis in osteosarcomas through a novel Nrf2/xCT/GPX4 regulatory axis

BACKGROUND

Osteosarcomas (OS) is a kind of malignant bone tumor which occurs primarily in children and adolescents, and the clinical therapeutics remain disappointing. As a new programmed cell death, ferroptosis is characterized by iron dependent and intracellular oxidative accumulation, which provides a potential alternative intervene for the OS treatment. Baicalin, a major bioactive flavone derived from traditional Chinese medicine Scutellaria baicalensis, has been proved to have anti-tumor properties in OS. Whether ferroptosis participated in the baicalin mediated anti-OS activity is an interesting project.

PURPOSE

To explore the pro-ferroptosis effect and mechanisms of baicalin in OS.

METHODS/STUDY DESIGN

Pro-ferroptosis effect of baicalin on cell death, cell proliferation, iron accumulation, lipid peroxidation production was determined in MG63 and 143B cells. The levels of glutathione (GSH), oxidized (GSSG) glutathione and malondialdehyde (MDA) were determined by enzyme linked immunosorbent assay (ELISA). The expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), Glutathione peroxidase 4 (GPX4) and xCT were detected by western blot in baicalin-mediated ferroptosis regulation. In vivo, a xenograft mice model was adopted to explore the anticancer effect of baicalin.

RESULTS

In the present study, it was found that baicalin significantly suppress tumor cell growth in vitro and in vivo. By promoting the Fe accumulation, ROS formation, MDA production and suppressing the ratio of GSH/GSSG, baicalin was found to trigger ferroptosis in OS and ferroptosis inhibitor ferrostatin-1 (Fer-1) successfully reversed these suppressive effects, indicating that ferroptosis participated in the baicalin mediated anti-OS activity. Mechanistically, baicalin physically interacted with Nrf2, a critical regulator of ferroptosis, and influenced its stability via inducing ubiquitin degradation, which suppressed the Nrf2 downstream targets GPX4 and xCT expression, and led to stimulating ferroptosis.

CONCLUSIONS

Our findings for the first time indicated that baicalin exerted anti-OS activity through a novel Nrf2/xCT/GPX4-dependent ferroptosis regulatory axis, which hopefully provides a promising candidate for OS treatment.

The Survival Outcomes, Prognostic Factors and Adverse Events following Systemic Chemotherapy Treatment in Bone Sarcomas: A Retrospective Observational Study from the Experience of the Cancer Referral Center in Northern Thailand

This study aimed to assess survival outcomes, prognostic factors, and adverse events following chemotherapy treatment for osteosarcoma and Ewing’s sarcoma. This retrospective observational study was conducted to collect the data of the patients with osteosarcoma or Ewing’s sarcoma who received chemotherapy treatment between 2008 and 2019. The flexible parametric survival model was performed to explore the adjusted survival probability and the prognostic factors. A total of 102 patients (79 with osteosarcoma and 23 with Ewing’s sarcoma) were included. The estimated 5-year disease-free survival (DFS) and 5-year overall survival (OS) probabilities in patients with resectable disease were 60.9% and 63.3% for osteosarcoma, and 54.4% and 88.3% for Ewing’s sarcoma, respectively, whereas the 5-year DFS and 5-year OS for those with unresectable/metastatic disease remained below 25%. Two prognostic factors for osteosarcoma included a response to neoadjuvant chemotherapy and female gender. Ewing’s sarcoma patients aged 25 years and older were significantly associated with poorer survival outcomes. Of 181 chemotherapy treatment cycles, common self-reported adverse symptoms included tumor pain (n = 32, 17.7%), fever (n = 21, 11.6%), and fatigue (n = 16, 8.8%), while common grade III adverse events included febrile neutropenia (n = 13, 7.3%) and neutropenia (n = 9, 5.1%). There was no chemotherapy-related mortality (grade V) or anaphylaxis events.

The Use of Hydrogels for the Treatment of Bone Osteosarcoma via Localized Drug-Delivery and Tissue Regeneration: A Narrative Review

Osteosarcoma is a malignant tumor of bone that leads to poor mortality and morbidity. Management of this cancer through conventional methods involves invasive treatment options that place patients at an increased risk of adverse events. The use of hydrogels to target osteosarcoma has shown promising results both in vitro and in vivo to eradicate tumor cells while promoting bone regeneration. The loading of hydrogels with chemotherapeutic drugs provides a route for site-specific targeted therapy for osteosarcoma. Current studies demonstrate tumor regression in vivo and lysis of tumor cells in vitro when exposed to doped hydrogel scaffolds. Additionally, novel stimuli-responsive hydrogels are able to react with the tissue microenvironment to facilitate the controlled release of anti-tumor drugs and with biomechanical properties that can be modulated. This narrative review of the current literature discusses both in vitro and in vivo studies of different hydrogels, including stimuli-responsive, designed to treat bone osteosarcoma. Future applications to address patient treatment for this bone cancer are also discussed.

Naturally occurring canine sarcomas: Bridging the gap from mouse models to human patients through cross-disciplinary research partnerships

Fueled by support from the National Cancer Institute's "Cancer Moonshot" program, the past few years have witnessed a renewed interest in the canine spontaneous cancer model as an invaluable resource in translational oncology research. Increasingly, there is awareness that pet dogs with cancer provide an accessible bridge to improving the efficiency of cancer drug discovery and clinical therapeutic development. Canine tumors share many biological, genetic, and histologic features with their human tumor counterparts, and most importantly, retain the complexities of naturally occurring drug resistance, metastasis, and tumor-host immune interactions, all of which are difficult to recapitulate in induced or genetically engineered murine tumor models. The utility of canine models has been particularly apparent in sarcoma research, where the increased incidence of sarcomas in dogs as compared to people has facilitated comparative research resulting in treatment advances benefitting both species. Although there is an increasing awareness of the advantages in using spontaneous canine sarcoma models for research, these models remain underutilized, in part due to a lack of more permanent institutional and cross-institutional infrastructure to support partnerships between veterinary and human clinician-scientists. In this review, we provide an updated overview of historical and current applications of spontaneously occurring canine tumor models in sarcoma research, with particular attention to knowledge gaps, limitations, and growth opportunities within these applications. Furthermore, we propose considerations for working within existing veterinary translational and comparative oncology research infrastructures to maximize the benefit of partnerships between veterinary and human biomedical researchers within and across institutions to improve the utility and application of spontaneous canine sarcomas in translational oncology research.

Osteosarcoma-enriched transcripts paradoxically generate osteosarcoma-suppressing extracellular proteins

Osteosarcoma (OS) is the common primary bone cancer that affects mostly children and young adults. To augment the standard-of-care chemotherapy, we examined the possibility of protein-based therapy using mesenchymal stem cells (MSCs)-derived proteomes and OS-elevated proteins. While a conditioned medium (CM), collected from MSCs, did not present tumor-suppressing ability, the activation of PKA converted MSCs into induced tumor-suppressing cells (iTSCs). In a mouse model, the direct and hydrogel-assisted administration of CM inhibited tumor-induced bone destruction, and its effect was additive with cisplatin. CM was enriched with proteins such as calreticulin, which acted as an extracellular tumor suppressor by interacting with CD47. Notably, the level of CALR transcripts was elevated in OS tissues, together with other tumor-suppressing proteins, including histone H4, and PCOLCE. PCOLCE acted as an extracellular tumor-suppressing protein by interacting with amyloid precursor protein, a prognostic OS marker with poor survival. The results supported the possibility of employing a paradoxical strategy of utilizing OS transcriptomes for the treatment of OS.

Abnormal signal pathways and tumor heterogeneity in osteosarcoma

BACKGROUND

Osteosarcoma (OS) is the most frequent and aggressive primary malignant sarcoma among adolescents and chemotherapy has not substantially progressed for decades. New insights into OS development and therapeutic strategies are urgently needed.

METHODS

We analyzed integrated single-cell transcriptomes, bulk RNA-seq, and microarray data from Gene Expression Omnibus (GEO) datasets. We also used Weighted Gene Co-expression Network Analysis (WGCNA), Gene set enrichment analysis (GSEA), and Gene set variation analysis (GSVA), along with Simple ClinVar and Enrichr web servers.

RESULTS

The findings of integrated single-cell analysis showed that OS arises from imperfect osteogenesis during development. Novel abnormalities comprised deficient TGFβ and P53 signal pathways, and cell cycle pathway activation, and a potentially new driver mutation in the interferon induced transmembrane protein 5 (IFITM5) that might function as a pathogenic factor in OS. Osteosarcoma is characterized by oncocyte heterogeneity, especially in immunogenic and adipocyte-like subtypes that respectively promote and hamper OS treatment. Etoposide is a promising chemotherapeutic that provides palliation by affecting the subtype of OS and correcting the abnormal pathways.

CONCLUSION

Various abnormal signal pathways play indispensable roles in OS development. We explored the heterogeneity and underlying mechanisms of OS and generated findings that will assist with OS assessment and selecting optimal therapies.

Analysis of prognostic factors and histopathological response to neoadjuvant chemotherapy in osteosarcoma

OBJECTIVES

This study aims to examine the clinical results of patients who underwent medical and surgical treatment for osteosarcoma, to determine the overall survival (OS) and disease-free survival (DFS) rates, and to examine the effects of prognostic factors on these rates.

PATIENTS AND METHODS

Between January 2005 and January 2020, a total of 64 patients (38 males, 26 females; mean age: 20.9±11.5 years; range, 6 to 70 years) who received medical and surgical treatment for osteosarcoma were retrospectively analyzed. Demographic characteristics, follow-up period, tumor location and size, tumor stage and necrosis rate, metastatic disease, surgical treatments, postoperative complications, local recurrence, and metastasis were recorded. The relationship of these factors with the survival was examined.

RESULTS

The median follow-up was 51.6 (range, 3 to 156) months. The most common tumor localization was in the distal femur with 42 (65.6%) patients and the most common histopathological subtypes were conventional osteosarcoma in 50 (78.1%) patients. The OS rates were 91.6% at one year, 65.9% at five years, and 51.6% at 10 years. With the exception of two patients who died during neoadjuvant chemotherapy, all patients underwent surgical treatment. The addition of chemotherapy + radiotherapy in the treatment did not provide any benefits in terms of survival and recurrence compared to the group that was not added, and the five-year OS rate was 79.3% compared to 20.7%, respectively. The overall 10-year survival rates were 83.9% and 37.2% in the group with a good response (≥90%) and poor response (<90%) to treatment (p=0.012). The mean survival time of three patients who presented with pathological fractures was shorter than the others (p>0.05). Surgical margin was ≤2 mm in 27 (42.2%) patients, >2 mm in 30 (46.9%) patients, and surgical margin was positive in five (7.8%) patients. The mean OS in the group with a surgical margin closure of >2 mm was 10.8±1.9 years and was longer than the other groups (p=0.047).

CONCLUSION

Metastasis at the time of diagnosis, <90% tumor necrosis, a tumor size of ≥10 cm, and metastasis development were significantly associated with poor survival and were found to be independent prognostic factors. The OS rate in the patient group with Stage III-IV response after neoadjuvant chemotherapy given the cisplatin + doxorubicin protocol was found to be better than those given the European and American Osteosarcoma Studies (EURAMOS) protocol. More research is needed to determine the most optimal chemotherapy protocols in this patient population. In addition, a multidisciplinary approach in treatment is of utmost importance to improve oncological outcomes.

ROS-Generating Hyaluronic Acid-Modified Zirconium Dioxide-Acetylacetonate Nanoparticles as a Theranostic Platform for the Treatment of Osteosarcoma

Materials that are able to produce free radicals have gained increasing attention for environmental and biomedical purposes. Free radicals, such as the superoxide anion (O₂^•-), act as secondary messengers in many physiological pathways, such as cell survival. Therefore, the production of free radicals over physiological levels has been exploited in the treatment of different types of cancer, including osteosarcoma (OS). In most cases, the production of reactive oxygen species (ROS) by materials is light-induced and requires the use of chemical photosensitisers, making it difficult and expensive. Here, for the first time, we propose photoluminescent hybrid ZrO₂-acetylacetonate nanoparticles (ZrO₂-acac NPs) that are capable of generating O₂^•- without light activation as an adjuvant for the treatment of OS. To increase the uptake and ROS generation in cancer cells, we modify the surface of ZrO₂-acac NPs with hyaluronic acid (HA), which recognizes and binds to the surface antigen CD44 overexpressed on OS cells. Since these nanoparticles emit in the visible range, their uptake into cancer cells can be followed by a label-free approach. Overall, we show that the generation of O₂^•- is toxic to OS cells and can be used as an adjuvant treatment to increase the efficacy of conventional drugs.

Nanocarriers in Veterinary Medicine: A Challenge for Improving Osteosarcoma Conventional Treatments

In recent years, several nanocarrier-based drug delivery systems, such as polymeric nanoparticles, solid lipid nanoparticles, metallic nanoparticles, liposomes, and others, have been explored to target and treat a wide variety of diseases. Their employment has brought many benefits, not only to human medicine but also to veterinary medicine, albeit at a slower rate. Soon, the use of nanocarriers could revolutionize the animal health sector, and many veterinary therapies will be more effective as a result. The purpose of this review is to offer an overview of the main applications of nanocarriers in the veterinary field, from supplements for animal health and reproduction to nanovaccines and nanotherapies. Among the major pathologies that can affect animals, special attention is given to canine osteosarcoma (OSA): a comparison with human OSA is provided and the main treatment options are reviewed emphasizing the benefits that nanocarriers could bring in the treatment of this widespread disease.

The Osteosarcoma Stem Cell Activity of a Gallium(III)-Phenanthroline Complex Appended to Salicylate

We report the synthesis, characterisation, and anti-osteosarcoma properties of a gallium(III) complex (1) comprising of two 1,10-phenanthroline ligands and salicylate, a non-steroidal anti-inflammatory drug. The gallium(III) complex 1 displays micromolar potency towards bulk osteosarcoma cells and osteosarcoma stem cells (OSCs). Notably, the gallium(III) complex 1 exhibits significantly higher toxicity towards OSCs grown in monolayer and three-dimensional cultures than cisplatin, a frontline anti-osteosarcoma drug. Nuclei isolation and immunoblotting studies show that the gallium(III) complex 1 enters osteosarcoma cell nuclei and induces DNA damage. Flow cytometry and cytotoxicity studies (in the presence of prostaglandin E2) indicate that the gallium(III) complex 1 downregulates cyclooxygenase-2 (COX-2) expression and kills osteosarcoma cells in a COX-2-dependent manner. Further, the mode of osteosarcoma cell death evoked by the gallium(III) complex 1 is characterised as caspase-dependent apoptosis.

ADCK1 is a potential therapeutic target of osteosarcoma

We here showed that ADCK1 (AarF domain-containing kinase 1), a mitochondrial protein, is upregulated in human osteosarcoma (OS) tissues and OS cells. In primary and established OS cells, ADCK1 shRNA or CRISPR/Cas9-induced ADCK1 knockout (KO) remarkably inhibited cell viability, proliferation and migration, and provoked apoptosis activation. Conversely, ectopic ADCK1 overexpression exerted pro-cancerous activity by promoting OS cell proliferation and migration. ADCK1 depletion disrupted mitochondrial functions in OS cells and induced mitochondrial membrane potential reduction, ATP depletion, reactive oxygen species production. Significantly, ADCK1 silencing augmented doxorubicin-induced apoptosis in primary OS cells. mTOR activation is important for ADCK1 expression in OS cells. The mTOR inhibitors, rapamycin and AZD2014, as well as mTOR shRNA, potently decreased ADCK1 expression in primary OS cells. In nude mice, the growth of subcutaneous pOS-1 xenografts was largely inhibited when bearing ADCK1 shRNA or ADCK1 KO construct. Moreover, ADCK1 KO largely inhibited pOS-1 xenograft in situ growth in proximal tibia of nude mice. ADCK1 depletion, apoptosis activation and ATP reduction were detected in pOS-1 xenografts bearing ADCK1 shRNA or ADCK1 KO construct. Together, the mitochondrial protein ADCK1 is required for OS cell growth and is a novel therapeutic target of OS.

Mediating effect assessment of ifosfamide on limb salvage rate in osteosarcoma: A study from a single center in China

Osteosarcoma is one of the most prevalent primary bone malignancies in children and adolescents. Surgery and chemotherapy are the standard treatment methods of osteosarcoma. Methotrexate, adriamycin, and cisplatin, and methotrexate, adriamycin, cisplatin, and ifosfamide regimens are both first-line neoadjuvant chemotherapy regimens for osteosarcoma. Moreover, the use of ifosfamide is highly controversial. Most studies of ifosfamide focused on the overall survival rate and event-free survival rate; few studies concentrated on surgical options. We conducted this retrospective study to compare the baseline characteristic of amputation and limb salvage osteosarcoma patients. Furthermore, we analyzed the direct and indirect roles in surgical decision-making and found that ifosfamide may play a partial mediating role in the surgery option choice by mediating tumor mass volume change, tumor response, and the shortest distance from the center of main blood vessels to the margin of the tumor lesion.

Therapeutic Potential of Ex Vivo Expanded γδ T Cells against Osteosarcoma Cells

Immunotherapy is an attractive therapeutic strategy for the treatment of osteosarcoma (OS). The unique features of γδ T cells have made them popular for cancer immunotherapy. Here, we expanded γδ T cells using human peripheral blood mononuclear cells (PBMCs) and investigated their therapeutic potential against OS cells. PBMCs from healthy donors were cultured for 10 days with CON medium (unstimulated control); EX media, CON with recombinant human interleukin-2 (rhIL-2) and zoledronate; and EX28 media, CON with rhIL-2, zoledronate, and CD3/CD28 activator. The expanded γδ T cells were isolated by magnetic cell separation or fluorescence-activated cell sorting, cultured with two OS cell lines (KHOS/NP and MG-63) at various cell ratios with or without doxorubicin or ifosfamide, and analyzed for cytotoxicity and cytokine secretion. The number of CD3+γδTCR+Vγ9+ triple-positive γδ T cells and concentrations of IFN-γ and TNF-α were highest in the rhIL-2 (100 IU) and zoledronate (1 μM) supplemented culture conditions. The CD3/CD28 agonist did not show any additional effects on γδ T cell expansion. The expanded γδ T cells exhibited potent in vitro cytotoxicity against OS in a ratio- and time-dependent manner. The γδ T cells may enhance the effect of chemotherapeutic agents against OS and may be a new treatment strategy, including chemo-immunotherapy, for OS.

Identification of Small-Molecule Inhibitors for Osteosarcoma Targeted Therapy: Synchronizing In Silico, In Vitro, and In Vivo Analyses

Objective: The study aimed to explore a new approach for the treatment of osteosarcoma through combining biomaterials with next-generation small molecule–based targeted therapy.

Methods: The model of osteosarcoma was established by 4-hydroxyaminoquinoline 1-oxide (4-HAQO) in mice while the collagen-thermosensitive hydrogel–calcium phosphate (CTC) biocomposites were prepared, and the small molecule inhibitors were virtually screened and synthesized. Then, for the osteosarcoma cell line, MG-63 cells were used to validate our bioinformatic findings in vitro, and the mouse osteosarcoma models were treated by combing CTC composites and small-molecule inhibitors after debridement.

Results: Five compounds, namely, ZINC150338698, ZINC14768621, ZINC4217203, ZINC169291448, and ZINC85537017, were found in the ZINK database. Finally, ZINC150338698 was selected for chemical synthesis and experimental verification. The results of the MTT assay and Hoechst staining showed that the small-molecule inhibitor ZINC150338698 could significantly induce MG-63 cell death. Furthermore, CTC composites and ZINC150338698 could repair the bone defects well after the debridement of osteosarcoma. In addition, the biomaterials and small-molecule inhibitors have good biocompatibility and biosafety.

Conclusion: Our findings not only offer systems biology approach-based drug target identification but also provide new clues for developing novel treatment methods for future osteosarcoma research.

MicroRNAs and osteosarcoma: Potential targets for inhibiting metastasis and increasing chemosensitivity

Osteosarcoma (OS) is the third most common cancer in young adults after lymphoma and brain cancer. Metastasis, like other cellular events, is dependent on signaling pathways; a series of changes in some proteins and signaling pathways pave the way for OS cells to invade and migrate. Ezrin, TGF-β, Notch, RUNX2, matrix metalloproteinases (MMPs), Wnt/β-catenin, and phosphoinositide 3-kinase (PI3K)/AKT are among the most important of these proteins and signaling pathways. Despite the improvements in treating OS, the overall survival of patients suffering from the metastatic disease has not experienced any significant change after surgical treatments and chemotherapy and 5-years overall survival in patients with metastatic OS is about 20%. Studies have shown that overexpression or inhibition of some microRNAs (miRNAs) has significant effects in limiting the invasion and migration of OS cells. The results of these studies highlight the potential of the clinical application of some miRNA mimics and miRNA inhibitors (antagomiRs) to inhibit OS metastasis in the future. In addition, some studies have shown that miRNAs are associated with the most important drug resistance mechanisms in OS, and some miRNAs are highly effective targets to increase chemosensitivity. The results of these studies suggest that miRNA mimics and antagomiRs may be helpful to increase the efficacy of conventional chemotherapy drugs in the treatment of metastatic OS. In this article, we discussed the role of various signaling pathways and the involved miRNAs in the metastasis of OS, attempting to provide a comprehensive review of the literature on OS metastasis and chemosensitivity.

Canine and murine models of osteosarcoma

Osteosarcoma (OS) is the most common malignant bone tumor in children. Despite efforts to develop and implement new therapies, patient outcomes have not measurably improved since the 1980s. Metastasis continues to be the main source of patient mortality, with 30% of cases developing metastatic disease within 5 years of diagnosis. Research models are critical in the advancement of cancer research and include a variety of species. For example, xenograft and patient-derived xenograft (PDX) mouse models provide opportunities to study human tumor cells in vivo while transgenic models have offered significant insight into the molecular mechanisms underlying OS development. A growing recognition of naturally occurring cancers in companion species has led to new insights into how veterinary patients can contribute to studies of cancer biology and drug development. The study of canine cases, including the use of diagnostic tissue archives and clinical trials, offers a potential mechanism to further canine and human cancer research. Advancement in the field of OS research requires continued development and appropriate use of animal models. In this review, animal models of OS are described with a focus on the mouse and tumor-bearing pet dog as parallel and complementary models of human OS.

Application of Approved Cisplatin Derivatives in Combination Therapy against Different Cancer Diseases

The problems with anticancer therapy are resistance and toxicity. From 3000 Cisplatin derivatives tested as antitumor agents, most of them have been rejected, due to toxicity. The aim of current study is the comparison of therapeutic combinations of the currently applied in clinical practice: Cisplatin, Carboplatin, Oxaliplatin, Nedaplatin, Lobaplatin, Heptaplatin, and Satraplatin. The literature data show that the strategies for the development of platinum anticancer agents and bypassing of resistance to Cisplatin derivatives and their toxicity are: combination therapy, Pt IV prodrugs, the targeted nanocarriers. The very important strategy for the improvement of the antitumor effect against different cancers is synergistic combination of Cisplatin derivatives with: (1) anticancer agents—Fluorouracil, Gemcitabine, Cytarabine, Fludarabine, Pemetrexed, Ifosfamide, Irinotecan, Topotecan, Etoposide, Amrubicin, Doxorubicin, Epirubicin, Vinorelbine, Docetaxel, Paclitaxel, Nab-Paclitaxel; (2) modulators of resistant mechanisms; (3) signaling protein inhibitors—Erlotinib; Bortezomib; Everolimus; (4) and immunotherapeutic drugs—Atezolizumab, Avelumab, Bevacizumab, Cemiplimab, Cetuximab, Durvalumab, Erlotinib, Imatinib, Necitumumab, Nimotuzumab, Nivolumab, Onartuzumab, Panitumumab, Pembrolizumab, Rilotumumab, Trastuzumab, Tremelimumab, and Sintilimab. An important approach for overcoming the drug resistance and reduction of toxicity of Cisplatin derivatives is the application of nanocarriers (polymers and liposomes), which provide improved targeted delivery, increased intracellular penetration, selective accumulation in tumor tissue, and enhanced therapeutic efficacy. The advantages of combination therapy are maximum removal of tumor cells in different phases; prevention of resistance; inhibition of the adaptation of tumor cells and their mutations; and reduction of toxicity.

Quercetin and Methotrexate in Combination have Anticancer Activity in Osteosarcoma Cells and Repress Oncogenic MicroRNA-223

INTRODUCTION

Osteosarcoma (OS) is one of the most common bone neoplasms in adolescents. Notable short- and long-term toxic effects of OS chemotherapy regimens have been reported. Hence, new chemotherapeutic agents with the ability to potentiate OS chemotherapy drugs and protect non-tumorous tissues are required.

METHODS

Saos-2 cells were treated with Methotrexate (MTX) and Quercetin (Que) (a polyphenolic flavonoid with anti-tumor effects) alone and in combination. MTT assay was performed to investigate the cytotoxicity of the drugs. Moreover, apoptosis-involved genes, including miR-223, p53, BCL-2, CBX7, and CYLD expression were analyzed via qRT-PCR. Annexin V-FITC/PI kit was employed to assess the apoptosis rate.

RESULTS

The MTT results showed that Que increases MTX cytotoxicity on OS cells. The measured IC50s are 142.3 µM for QUE and 13.7 ng/ml for MTX. A decline in MTX IC50 value was observed from 13.7 ng/ml to 8.45 ng/ml in the presence of Que. Moreover, the mRNA expression outcomes indicated that the combination therapy significantly up-regulates the tumor suppressor genes, such as p53, CBX7, and CYLD, and declines anti-apoptotic genes BCL-2 and miR-223, which can lead to proliferation inhibition and apoptosis inducement. Furthermore, the apoptosis rate increased significantly from 6.03% in the control group to 38.35% in Saos-2 cells that were treated with the combination of MTX and Que.

CONCLUSION

Que, with the potential to boost the anticancer activity of MTX on Saos-2 cancer cells through proliferation inhibition and apoptosis induction, is a good candidate for combination therapy.

Thymoquinone Augments Methotrexate-Induced Apoptosis on Osteosarcoma Cells

BACKGROUND

Osteosarcoma (OS) as the most frequent primary bone malignancy in children and adolescents has a short survival rate in advanced stages. Alternative herbal medicines with fewer side effects or the potency to protect common therapy's side effects can be helpful in combinational therapies. Herein, we aim to explore the effects of Thymoquinone (TQ) combined with Methotrexate (MTX) on Saos-2 cells apoptosis.

METHODS

The effects of TQ and MTX alone or in combination on Saos-2 cell viability were measured by MTT assay. Real-time PCR was applied for the measurement of Bax, BCL-2, and caspase-9 mRNA expression. Apoptosis evaluation was conducted by flow cytometry.

RESULTS

TQ improves the cytotoxic effects of MTX on Saos-2 cells proliferation at lower doses. Indeed, the IC50 of MTX decreased from 26 μM to 15 μM when it combined with TQ. TQ and MTX can induce the expression level of pro-apoptotic factors, Bax and caspase-9 while inhibiting anti-apoptotic protein BCL-2. Moreover, the combination of TQ and MTX potentiates apoptosis to 73%, compared to either TQ (48%) or MTX (53%) treated cells.

CONCLUSION

The co-treatment of TQ and MTX is associated with the up-regulation of apoptotic factors and down-regulation of anti-apoptotic factors, conducting apoptosis aggravation and OS cell death.

Prevalence, Risk Factors, and Prognostic Factors of Primary Malignant Bone Neoplasms with Bone Metastasis at Initial Diagnosis: A Population-Based Study

Background. Bone metastasis (BM) has been proven to be responsible for the poor prognosis of primary malignant bone neoplasms (PMBNs). We aimed to identify the prevalence, risk factors, and prognostic factors for PMBNs patients with BM based on the Surveillance, Epidemiology, and End Results (SEER) database. Methods. 4,758 patients diagnosed with PMBNs from 2010 to 2018 were selected from the SEER database. All patients were divided into two groups: the BM group or the non-BM group. Pearson’s chi-square test and Fisher’s exact method were used to assess baseline characteristics, and logistic regression analysis was applied to assess risk factors. In addition, a nomogram was constructed based on the results of Cox regression analysis among 227 patients with BM. The good performance and clinical applicability of the nomogram were tested by the concordance index, operating characteristic curve, area under the curve, calibration curves, and decision curve analysis. Results. 227 (4.8%) patients had metastasis to bone at diagnosis. Primary site outside the extremities (axial: odds ratio, $\text{OR}=1.770$ ; others: $\text{OR}=1.951$ ), Ewing sarcoma ( $\text{OR}=2.845$ ), larger tumor size (5–8 cm: $\text{OR}=3.403$ ; >8 cm: $\text{OR}=5.562$ ), tumor extension beyond the periosteum ( $\text{OR}=2.477$ ), and regional lymph node metastasis ( $\text{OR}=2.900$ ) were associated with a higher risk of BM at the initial diagnosis of PMBNs. Five independent prognostic factors were found in the survival analysis: pathological type (chondrosarcoma vs. osteosarcoma: hazard ratio, $\text{HR}=0.342$ ; Ewing sarcoma vs. osteosarcoma: $\text{HR}=0.592$ ; and chordoma vs. osteosarcoma: $\text{HR}=0.015$ ), marital status ( $\text{HR}=2.457$ ), pulmonary metastasis ( $\text{HR}=1.934$ ), surgery at the primary site ( $\text{HR}=0.164$ ), and chemotherapy ( $\text{HR}=0.084$ ). A nomogram based on these prognostic factors could be a good predictor of cancer-specific survival. Conclusions. We identified the prevalence, risk factors, and prognostic factors correlated with BM in PMBNs patients. The related nomogram could be a practical tool for therapeutic decision-making and individual counseling.

Two Beats One: Osteosarcoma Therapy with Light-Activated and Chemo-Releasing Keratin Nanoformulation in a Preclinical Mouse Model

Osteosarcoma treatment is moving towards more effective combination therapies. Nevertheless, these approaches present distinctive challenges that can complicate the clinical translation, such as increased toxicity and multi-drug resistance. Drug co-encapsulation within a nanoparticle formulation can overcome these challenges and improve the therapeutic index. We previously synthetized keratin nanoparticles functionalized with Chlorin-e6 (Ce6) and paclitaxel (PTX) to combine photo (PDT) and chemotherapy (PTX) regimens, and the inhibition of osteosarcoma cells growth in vitro was demonstrated. In the current study, we generated an orthotopic osteosarcoma murine model for the preclinical evaluation of our combination therapy. To achieve maximum reproducibility, we systematically established key parameters, such as the number of cells to generate the tumor, the nanoparticles dose, the design of the light-delivery device, the treatment schedule, and the irradiation settings. A 60% engrafting rate was obtained using 10 million OS cells inoculated intratibial, with the tumor model recapitulating the histological hallmarks of the human counterpart. By scheduling the treatment as two cycles of injections, a 32% tumor reduction was obtained with PTX mono-therapy and a 78% reduction with the combined PTX-PDT therapy. Our findings provide the in vivo proof of concept for the subsequent clinical development of a combination therapy to fight osteosarcoma.

Circular RNA_ANKIB1 accelerates chemo-resistance of osteosarcoma via binding microRNA-26b-5p and modulating enhancer of zeste homolog 2

Osteosarcoma is a common bone malignancy in children and adolescents. Chemotherapeutic drug resistance is the major factor impacting the surgical outcome and prognosis of patients with osteosarcoma. This investigation assessed the role and mechanism of circular RNA_ANKIB1 in the development of osteosarcoma. The circular RNA (circ) _ANKIB1, microRNA (miR)-26b-5p, enhancer of zeste homolog 2 (EZH2) expression in OS samples was investigated through RT-qPCR. The EZH2, multidrug resistance protein 1 (MRP1), P-gp, and lipoprotein receptor-related protein (LRP) protein expressions were analyzed through western blot. The association between circ_ANKIB1 and the occurrence of clinic-pathological features in OS patients was assessed; the circular features of circ_ANKIB1 were analyzed. The hFOB1.19, KHOS, U2-OS OS cells were used to study the semi-inhibitory concentration IC50 of Doxorubicin (DXR)-resistant cells, clone formation, invasion, and apoptosis. The luciferase assay was used to study the binding of circ-ANKIB1 with miR-26b-5p and the targeting of miR-26b-5p with EZH2. In vivo experiments were performed via subcutaneous tumorigenic experiments. MiR-26b-5p in OS tissues and cells and DXR-resistant OS tissues and cells was silenced while circ_ANKIB1 and EZH2 were elevated. Circ_ANKIB1 silencing elevated miR-26b-5p, repressed EZH2, MRP1, P-gp, LRP, IC50, and elevated OS advancement. Circ_ANKIB1 bind miR-26b-5p. Reduced miR-26b-5p revered the influence of silencing circ_ANKIB1 on DXR resistant OS cells. MiR-26b-5p targeted EZH2, and EZH2 elevation reversed the impact of increasing miR-26b-5p on DXR resistant cells. Circ_ANKIB1 silencing suppressed DXR-resistant OS cells in vivo. In conclusion, Circ_ANKIB1 binds miR-26b-5p and modulates EZH2 to accelerate the chemo-resistance of osteosarcoma.

Efficacy of ifosfamide combined with liposome doxorubicin on osteosarcoma and its effects on serum IL-10, TNF-α, and IFN-γ in patients with osteosarcoma

OBJECTIVE

To evaluate the effects of ifosfamide combined with liposome doxorubicin on osteosarcoma (OS) and its effects on serum IL-10, TNF-α, and IFN-γ in patients with OS.

METHODS

A total of 86 patients with OS who received chemotherapy in Honghui Hospital, Xi'an Jiaotong University from Jan. 2017 to Dec. 2019 were enrolled. Patients treated by conventional doxorubicin + ifosfamide were assigned to the regular group (n=40). Others treated by liposome doxorubicin + ifosfamide were assigned to the research group (n=46). The clinical efficacy, 2-year survival rate, and adverse reactions of the two groups were evaluated and compared. ELISA was adopted for quantification of tumor specific growth factor (TSGF), vascular endothelial growth factor (VEGF), erb-b2 receptor tyrosine kinase 3 (ERBB3), tumor necrosis factor-α (TNF-α), interferon-gamma-γ (IFN-γ), and interleukin-10 (IL-10). The EORTC Quality of Life Questionnaire (QLQ-C30) was adopted to evaluate a patient's life quality.

RESULTS

The research group showed a higher total effective rate and a higher 2-year survival rate than the regular group, but lower incidences of liver and kidney function injury, thrombocytopenia, and cardiotoxicity than the regular group. After therapy, lower levels of serum TSGF, VEGF, ERBB3, and TNF-α were found in the research group than those in the regular group. Higher levels of IFN-γ and IL-10 were found in the former than those in the latter. The research group got higher scores of QLQ-C30 than the regular group.

CONCLUSION

Liposome doxorubicin + ifosfamide can improve the clinical efficacy on patients with OS and improve their recovery and life quality.

Abemaciclib is synergistic with doxorubicin in osteosarcoma pre-clinical models via inhibition of CDK4/6-Cyclin D-Rb pathway

BACKGROUND

Osteosarcoma is a prevalent type of bone tumor in children and adolescents, with limited treatment and poor prognosis. Abemaciclib, an inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), is approved for the treatment of advanced breast cancer as single agent therapy and is currently under investigation in clinical trials for the treatment of several solid tumors.

METHODS

The efficacy of abemaciclib was determined using osteosarcoma cellular assays and xenograft mouse model. The combination studies were performed based on the Chou-Talalay method. Immunoblotting analysis was performed to determine the underlying mechanisms of abemaciclib in osteosarcoma cell lines.

RESULTS

Abemaciclib potently inhibits growth, anchorage-independent colony formation and survival of a panel of osteosarcoma cell lines, with IC50 range from 90 nM to >20 μM. In addition, the combination of abemaciclib and doxorubicin is synergistic and antagonistic in abemaciclib-sensitive (IC50 <1 μM) and abemaciclib-resistant (IC50 >1 μM), respectively. Abemaciclib inhibits tumor formation and growth in a dose-dependent manner without causing significant drug toxicity in mice. The combination of abemaciclib and doxorubicin results in much greater efficacy than doxorubicin alone in inhibiting tumor growth throughout the whole treatment duration. Abemaciclib acts on osteosarcoma via suppressing CDK4/6-Cyclin D-Rb pathway.

CONCLUSIONS

Our pre-clinical evidence provides a rationale of initializing clinical trial of investigating the efficacy of abemaciclib in combination with doxorubicin in osteosarcoma patients. Our work also highlights the therapeutic value of CDK4/6 inhibition in osteosarcoma with proper function of Rb.

Osteogenesis in the presence of chemotherapy: A biomimetic approach

Osteosarcoma (OS) is the most common bone tumor in pediatrics. After resection, allografts or metal endoprostheses reconstruct bone voids, and systemic chemotherapy is used to prevent recurrence. This urges the development of novel treatment options for the regeneration of bone after excision. We utilized a previously developed biomimetic, biodegradable magnesium-doped hydroxyapatite/type I collagen composite material (MHA/Coll) to promote bone regeneration in the presence of chemotherapy. We also performed experiments to determine if human mesenchymal stem cells (hMSCs) seeded on MHA/Coll scaffold migrate less toward OS cells, suggesting that hMSCs will not contribute to tumor growth and therefore the potential of oncologic safety in vitro. Also, hMSCs seeded on MHA/Coll had increased expression of osteogenic genes ( BGLAP, SPP1, ALP) compared to hMSCs in the 2D condition, even when exposed to chemotherapeutics. This is the first study to demonstrate that a highly osteogenic scaffold can potentially be oncologically safe because hMSCs on MHA/Coll tend to differentiate and lose the ability to migrate toward tumor cells. Therefore, hMSCs on MHA/Coll could potentially be utilized for bone regeneration after OS excision.

Impact of limb amputation and cisplatin chemotherapy on metastatic progression in mouse models of osteosarcoma

Development of animal models that accurately recapitulate human cancer is an ongoing challenge. This is particularly relevant in the study of osteosarcoma (OS), a highly malignant bone tumor diagnosed in approximately 1000 pediatric/adolescent patients each year. Metastasis is the leading cause of patient death underscoring the need for relevant animal models of metastatic OS. In this study, we describe how existing OS mouse models can be interrogated in a time-course context to determine the kinetics of spontaneous metastasis from an orthotopically implanted primary tumor. We evaluated four highly metastatic OS cell lines (3 human, 1 mouse) to establish a timeline for metastatic progression in immune deficient NSG mice. To discern the effects of therapy on tumor development and metastasis in these models, we investigated cisplatin therapy and surgical limb amputation at early and late timepoints. These data help define the appropriate observational periods for studies of metastatic progression in OS and further our understanding of existing mouse models. Efforts to advance the study of metastatic OS are critical for facilitating the identification of novel therapeutics and for improving patient survival.

Unveiling Metabolic Vulnerability and Plasticity of Human Osteosarcoma Stem and Differentiated Cells to Improve Cancer Therapy

Defining the metabolic phenotypes of cancer-initiating cells or cancer stem cells and of their differentiated counterparts might provide fundamental knowledge for improving or developing more effective therapies. In this context we extensively characterized the metabolic profiles of two osteosarcoma-derived cell lines, the 3AB-OS cancer stem cells and the parental MG-63 cells. To this aim Seahorse methodology-based metabolic flux analysis under a variety of conditions complemented with real time monitoring of cell growth by impedentiometric technique and confocal imaging were carried out. The results attained by selective substrate deprivation or metabolic pathway inhibition clearly show reliance of 3AB-OS on glycolysis and of MG-63 on glutamine oxidation. Treatment of the osteosarcoma cell lines with cisplatin resulted in additive inhibitory effects in MG-63 cells depleted of glutamine whereas it antagonized under selective withdrawal of glucose in 3AB-OS cells thereby manifesting a paradoxical pro-survival, cell-cycle arrest in S phase and antioxidant outcome. All together the results of this study highlight that the efficacy of specific metabolite starvation combined with chemotherapeutic drugs depends on the cancer compartment and suggest cautions in using it as a generalizable curative strategy.

Evaluation of the Chemotherapy Drug Response Using Organotypic Cultures of Osteosarcoma Tumours from Mice Models and Canine Patients

Simple Summary

Osteosarcoma is a bone cancer with 75% of cases occurring in people younger than 25 years old. 35–45% of patients demonstrate resistance to chemotherapeutics and critically, survival rates for osteosarcoma is only 10–30% for patients with metastases. Therefore, reliable and patient-specific drug testing modalities are needed. Organotypic slice culture consists of sections of tumours, which survive and preserve the tumours mechanical and cellular properties, thereby enabling personalised testing of drugs. This study aimed to characterise organotypic slice cultures of osteosarcoma bone tumours derived from mice and dogs and to use these models for testing of anti-tumoural drugs. This study reports the various cell constituents of the model and the maintenance of osteosarcoma organotypic cultures over several weeks. A significantly decreased sensitivity to chemotherapy in 3D organotypic culture relative to 2D monolayer was found, highlighting the need to test anti-cancer drugs in a more personalized and biomimetic manner.

Abstract

Improvements in the clinical outcome of osteosarcoma have plateaued in recent decades with poor translation between preclinical testing and clinical efficacy. Organotypic cultures retain key features of patient tumours, such as a myriad of cell types organized within an extracellular matrix, thereby presenting a more realistic and personalised screening of chemotherapeutic agents ex vivo. To test this concept for the first time in osteosarcoma, murine and canine osteosarcoma organotypic models were maintained for up to 21 days and in-depth analysis identified proportions of immune and stromal cells present at levels comparable to that reported in vivo in the literature. Cytotoxicity testing of a range of chemotherapeutic drugs (mafosfamide, cisplatin, methotrexate, etoposide, and doxorubicin) on murine organotypic culture ex vivo found limited response to treatment, with immune and stromal cells demonstrating enhanced survival over the global tumour cell population. Furthermore, significantly decreased sensitivity to a range of chemotherapeutics in 3D organotypic culture relative to 2D monolayer was observed, with subsequent investigation confirming reduced sensitivity in 3D than in 2D, even at equivalent levels of drug uptake. Finally, as proof of concept for the application of this model to personalised drug screening, chemotherapy testing with doxorubicin was performed on biopsies obtained from canine osteosarcoma patients. Together, this study highlights the importance of recapitulating the 3D tumour multicellular microenvironment to better predict drug response and provides evidence for the utility and possibilities of organotypic culture for enhanced preclinical selection and evaluation of chemotherapeutics targeting osteosarcoma.

Chlorogenic Acid Enhances Doxorubicin-Mediated Cytotoxic Effect in Osteosarcoma Cells

Despite the recurring outbreak of resistance mechanisms and adverse reactions, doxorubicin (Doxo) still remains the standard-of-care for several cancers, including osteosarcoma (OS). As an appealing source of phytochemical compounds, naturally occurring molecules have extensively been reported to overcome Doxo limitations in preclinical models. Unlike other dietary polyphenols, only few studies recognize chlorogenic acid (CGA) as a potential partner in combination therapy, while, conversely, its anticancer evidence is steadily growing, ultimately in OS. On this basis, herein we examine the cooperating effects between CGA and Doxo in U2OS and MG-63 human OS cells. With respect to Doxo alone, the concomitant administration of CGA further decreased cell viability and growth, promoting cell death potentially via apoptosis induction. Furthermore, a longer-lasting reduction in clonogenic potential deeply supported the CGA ability to improve Doxo efficacy in those cells. Remarkably, CGA treatment ameliorated Doxo-induced cytotoxicity in H9c2 rat cardiomyocyte cells instead. Although inactivation of p44/42 MAPK was detected in response to CGA plus Doxo, PD98059-mediated p44/42 MAPK impairment enhanced the combination outcome in OS cells. These findings firstly propose CGA as a promising chemosensitizer and cardioprotective agent in OS therapy, suggesting the p44/42 MAPK pathway as relevantly involved in CGA-mediated Doxo susceptibility.

Investigating Optimal Chemotherapy Options for Osteosarcoma Patients through a Mathematical Model

Simple Summary

Osteosarcoma is a rare type of cancer with poor prognoses. However, to the best of our knowledge, there are no mathematical models that study the impact of chemotherapy treatments on the osteosarcoma microenvironment. In this study, we developed a data driven mathematical model to analyze the dynamics of the important players in three groups of osteosarcoma tumors with distinct immune patterns in the presence of the most common chemotherapy drugs. The results indicate that the treatments’ start times and optimal dosages depend on the unique growth rate of the tumor, which implies the necessity of personalized medicine. Furthermore, the developed model can be extended by others to build models that can recommend individual-specific optimal dosages.

Abstract

Since all tumors are unique, they may respond differently to the same treatments. Therefore, it is necessary to study their characteristics individually to find their best treatment options. We built a mathematical model for the interactions between the most common chemotherapy drugs and the osteosarcoma microenvironments of three clusters of tumors with unique immune profiles. We then investigated the effects of chemotherapy with different treatment regimens and various treatment start times on the behaviors of immune and cancer cells in each cluster. Saliently, we suggest the optimal drug dosages for the tumors in each cluster. The results show that abundances of dendritic cells and HMGB1 increase when drugs are given and decrease when drugs are absent. Populations of helper T cells, cytotoxic cells, and IFN-γ grow, and populations of cancer cells and other immune cells shrink during treatment. According to the model, the MAP regimen does a good job at killing cancer, and is more effective than doxorubicin and cisplatin combined or methotrexate alone. The results also indicate that it is important to consider the tumor’s unique growth rate when deciding the treatment details, as fast growing tumors need early treatment start times and high dosages.

Combination Therapy of Cisplatin and other Agents for Osteosarcoma: A Review

Background:

Osteosarcoma is the most common type of primary bone tumor in children and adolescents, which is associated with rapid progression and poor prognosis. Multimodal therapy is the most common approach utilized for osteosarcoma management, such as the application of chemotherapy in combination with surgery or radiation therapy. Cisplatin is one of the predominantly used chemotherapeutic agents for osteosarcoma. Optimally, it is employed in combination with other chemotherapeutic drugs along with surgery or radiation therapy. Despite the availability of numerous treatment approaches, the patient survival rate has not definitively improved over the past three decades.

Methods:

We have summarized all findings regarding the combination of cisplatin with other chemotherapeutic agents as well as with phytochemical compounds.

Results:

A combination of cisplatin with a phytochemical compound synergistically enhances the killing effect of cisplatin on osteosarcoma cells with fewer side effects compared to combination with other chemotherapeutic agents.

Conclusion:

Conclusively, a combination of cisplatin with selected chemotherapeutic drugs has been shown to be effective. However, the unchanged survival rate has posed an urge to search for a new combination regimen. As a collaborative effort to substantiate the therapeutic efficacy, the combination with phytochemical compounds shows a promising response both in vitro as well as in the preclinical study.

Circular RNA circPVT1 Contributes to Doxorubicin (DXR) Resistance of Osteosarcoma Cells by Regulating TRIAP1 via miR-137

Background

Chemoresistance is a major obstacle to the treatment of osteosarcoma patients. Circular RNA (circRNA) circPVT1 has been reported to be related to the doxorubicin (DXR) resistance in osteosarcoma. This study is designed to explore the role and mechanism of circPVT1 in the DXR resistance of osteosarcoma.

Methods

circPVT1, microRNA-137 (miR-137), and TP53-regulated inhibitor of apoptosis 1 (TRIAP1) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The protein levels of ATP-binding cassette, subfamily C, member 1 (ABCC1), multidrug resistance-associated protein 1 (MRP-1), cleaved- (c-) caspase-3, B-cell lymphoma-2 (Bcl-2), and TRIAP1 were examined by a western blot assay. Cell viability, proliferation, and apoptosis were detected by cell counting kit-8 (CCK-8), colony formation, and flow cytometry assays, severally. The binding relationship between miR-137 and circPVT1 or TRIAP1 was predicted by starbase 3.0 and then verified by dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. The biological role of circPVT1 in osteosarcoma tumor growth and drug resistance was examined by the xenograft tumor model in vivo. Results. circPVT1 and TRIAP1 were highly expressed, and miR-137 was decreased in DXR-resistant osteosarcoma tissues and cells. Moreover, circPVT1 knockdown could boost DXR sensitivity by inhibiting DXR-caused proliferation and DXR-induced apoptosis in DXR-resistant osteosarcoma cells in vitro. The mechanical analysis discovered that circPVT1 acted as a sponge of miR-137 to regulate TRIAP1 expression. circPVT1 silencing increased the drug sensitivity of osteosarcoma in vivo. Conclusion. circPVT1 boosted DXR resistance of osteosarcoma cells partly by regulating the miR-137/TRIAP1 axis, hinting a promising therapeutic target for the osteosarcoma treatment.

What's New in Pediatric Orthopaedic Tumor Surgery

BACKGROUND

Pediatric Orthopaedic Oncology is a developing subspecialty within the field of Pediatric Orthopaedics. Traditionally, the field of Orthopaedic Oncology has been focused on the skeletally mature individual, and the research tends to be all encompassing rather than truly evaluating isolated populations. The purpose of this review is to summarize the most clinically relevant literature in the field of Pediatric Orthopaedic Oncology over the last 6 years.

METHODS

We evaluated the PubMed database utilizing keywords for pediatric orthopaedic oncology: sarcoma, osteosarcoma, Ewing sarcoma, bone cyst. In additionally, we further broadened our search by searching for relevant articles in the contents sections of major orthopaedic surgery journals that routinely publish both pediatric and orthopaedic oncology literature. In keeping with "What's New," we selected the most clinically relevant articles published in the last 6 years from January 1, 2014 through February 2020. Basic science and systemic therapies literature was widely reviewed and the research and clinical trials most relevant to pediatric sarcoma and neoplastic processes found in the pediatric population were included.

RESULTS

Our search yielded 60 articles that met general criteria, from which 14 were determined to be most relevant to the goals of this paper. Of the papers presented in this review, there were papers related to management of benign tumors/tumor-like conditions, bone cysts, limb salvage procedures, and amputation procedures. Ultimately included in the review were 5 studies related to limb salvage, 4 related to bone cysts, 1 related to multiple hereditary exostoses, 2 related to osteofibrous dysplasia, 1 related to chondroblastoma, and 1 discussing cementation in skeletally immature patients. They were level III, IV, and V studies. Basic science and systemic therapies literature was widely reviewed and the research and clinical trials most relevant to pediatric sarcoma and neoplastic processes found in the pediatric population were included. Our search of the basic science and systemic therapies literature yielded 19 sources were found to be pertinent to our aims and 18 of those sources were published between 2015 and 2020.

CONCLUSIONS

There are many, varied, and creative procedures in the realm of limb salvage, though there remains a lack of high-level evidence to support some of the more novel procedures. In regards to benign bone tumors, despite a more solid base of literature, there still does not seem to be consensus as to the best treatment. In particular, there continue to be many schools of thought on the treatment of benign bone cysts. Research in the basic science arena and systemic therapies are advancing in exciting ways in regards to pediatric sarcoma. Orthopaedic oncologic research specific to the pediatric population overall continues to be impeded by low sample sizes and inadequate levels of evidence, which limits the ability of surgeons to draw definitive conclusions from the literature.

ROCK2 Promotes Osteosarcoma Growth and Glycolysis by Up-Regulating HKII via Phospho-PI3K/AKT Signalling

Background

Osteosarcoma (OS) is a malignant bone tumour that exhibits a high mortality. While tumours thrive in a state of malnutrition, the mechanism by which OS cells adapt to metabolic stress through metabolic reprogramming remains unclear.

Methods

We analysed the expression of ROCK2 in osteosarcoma tissues by RT-qPCR and Western blot. Cell proliferation were analysed using CCK8, EdU and colony formation assays. The level of cell glycolysis was detected by glucose-6 phosphate, glucose consumption, lactate production and ATP levels.

Results

Herein, our study showed that ROCK2 expression in OS tissues was higher than in adjacent tissues. Functional assays have demonstrated that ROCK2 contributes to the growth of OS cells by inducing aerobic glycolysis. The current study revealed that ROCK2 knockdown decreased the levels of mitochondrial hexokinase II (HKII). And also indicated that ROCK2 served as a key enzyme in glycolysis and that it served an important role in tumour growth. A significant positive correlation was identified between the mRNA and protein expressions of ROCK2 and HKII, further demonstrating that ROCK2-induced glycolysis and proliferation was dependent on HKII expression in OS cells. Mechanistically, ROCK2 promotes HKII expression by activating the phospho-PI3K/AKT signalling pathway.

Conclusion

Taken together, the results of the current study linked the two drivers of OS growth and aerobic glycolysis and identified a new mechanism of ROCK2 control in OS.

Creating In Vitro Three-Dimensional Tumor Models: A Guide for the Biofabrication of a Primary Osteosarcoma Model

Osteosarcoma (OS) is a highly aggressive primary bone tumor. The mainstay for its treatment is multiagent chemotherapy and surgical resection, with a 50-70% 5-year survival rate. Despite the huge effort made by clinicians and researchers in the past 30 years, limited progress has been made to improve patient outcomes. As novel therapeutic approaches for OS become available, such as monoclonal antibodies, small molecules, and immunotherapies, the need for OS preclinical model development becomes equally pressing. Three-dimensional (3D) OS models represent an alternative system to study this tumor: In contrast to two-dimensional monolayers, 3D matrices can recapitulate key elements of the tumor microenvironment (TME), such as the cellular interaction with the bone mineralized matrix. The advancement of tissue engineering and biofabrication techniques enables the incorporation of specific TME aspects into 3D models, to investigate the contribution of individual components to tumor progression and enhance understanding of basic OS biology. The use of biomaterials that mimic the extracellular matrix could also facilitate the testing of drugs targeting the TME itself, allowing a larger range of therapeutics to be tested, while averting the ethical implications and high cost associated with in vivo preclinical models. This review aims at serving as a practical guide by delineating the OS TME ("what it is like") and, in turn, propose various biofabrication strategies to create a 3D model ("how to recreate it"), to improve the in vitro representation of the OS tumor and ultimately generate more accurate drug response profiles.

Enhanced Antiproliferative Effect of Combined Treatment with Calcitriol and All-Trans Retinoic Acid in Relation to Vitamin D Receptor and Retinoic Acid Receptor α Expression in Osteosarcoma Cell Lines

The main objective of this study was to analyze changes in the antiproliferative effect of vitamin D3, in the form of calcitriol and calcidiol, via its combined application with all-trans retinoic acid (ATRA) in osteosarcoma cell lines. The response to treatment with calcitriol and calcidiol alone was specific for each cell line. Nevertheless, we observed an enhanced effect of combined treatment with ATRA and calcitriol in the majority of the cell lines. Although the levels of respective nuclear receptors did not correlate with the sensitivity of cells to these drugs, vitamin D receptor (VDR) upregulation induced by ATRA was found in cell lines that were the most sensitive to the combined treatment. In addition, all these cell lines showed high endogenous levels of retinoic acid receptor α (RARα). Our study confirmed that the combination of calcitriol and ATRA can achieve enhanced antiproliferative effects in human osteosarcoma cell lines in vitro. Moreover, we provide the first evidence that ATRA is able to upregulate VDR expression in human osteosarcoma cells. According to our results, the endogenous levels of RARα and VDR could be used as a predictor of possible synergy between ATRA and calcitriol in osteosarcoma cells.

Vanillin Prevents Doxorubicin-Induced Apoptosis and Oxidative Stress in Rat H9c2 Cardiomyocytes

Doxorubicin (doxo) is an effective anticancer compound in several tumor types. However, as a consequence of oxidative stress induction and ROS overproduction, its high cardiotoxicity demands urgent attention. Vanillin possesses antioxidant, antiproliferative, antidepressant and anti-glycating properties. Therefore, we investigated the potential vanillin protective effects against doxo-induced cardiotoxicity in H9c2 cells. Using multiparametric approach, we demonstrated that vanillin restored both cell viability and damage in response to doxo exposure. Contextually, vanillin decreased sub-G1 appearance and caspase-3 and PARP1 activation, reducing the doxo-related apoptosis induction. From a mechanistic point of view, vanillin hindered doxo-induced ROS accumulation and impaired the ERK phosphorylation. Notably, besides the cardioprotective effects, vanillin did not counteract the doxo effectiveness in osteosarcoma cells. Taken together, our results suggest that vanillin ameliorates doxo-induced toxicity in H9c2 cells, opening new avenues for developing alternative therapeutic approaches to prevent the anthracycline-related cardiotoxicity and to improve the long-term outcome of antineoplastic treatment.