The safety of current pharmacotherapeutic strategies for osteosarcoma

Casticin induces ferroptosis in human osteosarcoma cells through Fe2+ overload and ROS production mediated by HMOX1 and LC3-NCOA4

Osteosarcoma is a primary solid bone malignancy, and surgery + chemotherapy is the most commonly used treatment. However, chemotherapeutic drugs can cause a range of side effects. Casticin, a polymethoxyflavonoid, has anti-tumor therapeutic effects. This study is aim to investigate the anti-osteosarcoma activity of casticin and explore the mechanism. Crystal violet staining, MTT assay, colony formation assay, wound healing assay, transwell assay, hoechst 33,258 staining, and flow cytometry analysis were used to investigate the effects of casticin on proliferation, migration, invasion, and apoptosis of osteosarcoma cells in vitro. The intracellular Fe2+, ROS, MDA, GSH/GSSG content changes were detected using the corresponding assay kits. The mRNA sequencing + bioinformatics analysis and western blot were used to detect the possible mechanism. We found that casticin caused G2/M phase cell cycle arrest in human osteosarcoma cells, inhibited the migration and invasion, and induced cell apoptosis and ferroptosis. Mechanistic studies showed the ferroptosis pathway was enriched stronger than apoptosis. Casticin up-regulated the expression of HMOX1, LC3 and NCOA4, meanwhile it activated MAPK signaling pathways. Animal experiments proved that casticin also inhibited the growth and metastasis of osteosarcoma cell xenograft tumor in vivo. In conclusion, casticin can induce ferroptosis in osteosarcoma cells through Fe2+ overload and ROS production mediated by HMOX1 and LC3-NCOA4. This provides a new strategy for osteosarcoma treatment.

EphA2-specific microvesicles derived from tumor cells facilitate the targeted delivery of chemotherapeutic drugs for osteosarcoma therapy

Despite advances in surgery and chemotherapy, the survival of patients with osteosarcoma (OS) has not been fundamentally improved over the last two decades. Microvesicles (MVs) have a high cargo-loading capacity and are emerging as a promising drug delivery nanoplatform. The aim of this study was to develop MVs as specifically designed vehicles to enable OS-specific targeting and efficient treatment of OS. Herein, we designed and constructed a nanoplatform (YSA-SPION-MV/MTX) consisting of methotrexate (MTX)-loaded MVs coated with surface-carboxyl Fe3O4 superparamagnetic nanoparticles (SPIONs) conjugated with ephrin alpha 2 (EphA2)-targeted peptides (YSAYPDSVPMMS, YSA). YSA-SPION-MV/MTX showed an effective targeting effect on OS cells, which was depended on the binding of the YSA peptide to EphA2. In the orthotopic OS mouse model, YSA-SPION-MV/MTX effectively delivered drugs to tumor sites with specific targeting, resulting in superior anti-tumor activity compared to MTX or MV/MTX. And YSA-SPION-MV/MTX also reduced the side effects of high-dose MTX. Taken together, this strategy opens up a new avenue for OS therapy. And we expect this MV-based therapy to serve as a promising platform for the next generation of precision cancer nanomedicines.

Palladium (II) compounds containing oximes as promising antitumor agents for the treatment of osteosarcoma: An in vitro and in vivo comparative study with cisplatin

Drug resistance, evasion of cell death and metastasis are factors that contribute to the low cure rate and disease-free survival in osteosarcomas (OS). In this study, we demonstrated that a new class of oxime-containing organometallic complexes called Pd-BPO (O3) and Pd-BMO (O4) are more cytotoxic than cisplatin (CDDP) for SaOS-2 and U2OS cells using the MTT assay. Annexin-FITC/7-AAD staining demonstrated a greater potential for palladium-oxime complexes to induce death in SaOS-2 cells than CDDP, an event confirmed using the pan-caspase inhibitor Z-VAD-FMK. Compared to CDDP, only palladium-oxime complexes eradicated the clonogenicity of SaOS-2 cells after 7 days of treatment. The involvement of the lysosome-mitochondria axis in the cell death-inducing properties of the complexes was also evaluated. Using LysoTracker Red to label the acidic organelles of SaOS-2 cells treated with the O3 and O4 complexes, a decrease in the fluorescence intensity of this probe was observed in relation to CDDP and the control. Lysosomal membrane permeabilization (LMP) was also induced by the O3 and O4 complexes in an assay using acridine orange (A/O). The greater efficiency of the complexes in depolarizing the mitochondrial membrane compared to SaOS-2 cells treated with CDDP was also observed using TMRE (tetramethyl rhodamine, ethyl ester). For in vivo studies, C. elegans was used and demonstrated that both complexes reduce body bends and pharyngeal pumping after 24 h of treatment to the same extent as CDDP. We conclude that both palladium-oxime complexes are more effective than CDDP in inducing tumor cell death. The toxicity of these complexes to C. elegans was like that induced by CDDP. These results encourage preclinical studies aimed at developing more effective drugs for the treatment of osteosarcoma (OS). Furthermore, we propose palladium-oxime complexes as a new class of antineoplastic agents.

Beyond 5-year survival. A report from the Cooperative Osteosarcoma Study Group (COSS)

PURPOSE

Prognostic factors have been well described for osteosarcoma, but analyses evaluating the further course of long-term survivors are lacking. We used the large database of the Cooperative Osteosarcoma Study Group (COSS) to perform such an analysis.

PATIENTS AND METHODS

The COSS database 1980-04/2019 was searched for 5-year survivors of primary high-grade central osteosarcoma of the extremities or trunk. Identified patients were analyzed for their further survival outcomes, assessing potentially prognostic and predictive factors already evident at initial disease presentation and treatment as well as their disease course during the first 5 years of follow-up.

RESULTS

Two thousand and nine former eligible patients were identified (median age at initial diagnosis 15.1 (2.5-63.0) years; male vs. female 1149 (57.2%) vs. 860 (42.8%); extremities vs. trunk 1927 (95.9%) vs. 82 (4.1%); extremity primaries <1/3 vs. ≥1/3 of the involved bone 997 (67.8%) vs. 474 (32.2%) (456 unknown); localized vs. primary metastatic 1881 (93.6%) vs. 128 (6.4%); osteosarcoma as a secondary malignancy 41/2009 (2.0%)). Therapy starting by chemotherapy versus primary surgery 1860 (92.6%) versus 149 (7.4%); definitive tumor surgery by limb salvage versus ablative 1347 (67.0%) versus 659 (1 no surgery, 2 unknown); tumor response to preoperative chemotherapy documented for 1765 (94.9%) patients receiving neoadjuvant chemotherapy, good (<10% viable tumor) versus poor 1130 (64.0%) versus 635 (36.0%), local radiotherapy documented for 19 (0.9%) tumors. Recurrence during preceding 5 years no versus yes 1681 (83.7%) versus 328 (16.3%). Median follow-up starting 5 years after initial diagnosis 6.1 (0.002-32.2) years; 1815 survivors and 194 deaths. Overall survival after another 5/10/15/20 years 91.7%/88.9%/85.8%/83.4% for all patients; 97.5%/95.2%/92.4%/89.9% if in remission years 1-5 versus 62.7%/57.3%/53.0%/51.2% if recurrence year 1-5 (p < 0.001). Significant predictors of survival for all patients age at diagnosis (p = 0.038), tumor site (p = 0.030), having experienced the osteosarcoma as secondary malignancy (p < 0.001), tumor response to preoperative chemotherapy (p = 0.002). Multivariate Cox regression testing possible for 1759 (87.6%) patients with complete dataset: Having had a recurrence in years 1-5 (p < 0.001), older age at diagnosis (p = 0.009), and osteosarcoma as secondary malignancy (p = 0.013) retained significance.

DISCUSSION

Highly important predictors of death such as the extent of tumor response to chemotherapy no longer remain valid after 5-year survival. The individual history of malignancies and their outcomes seems to gain pivotal importance.

CONCLUSION

This benchmark analysis clearly defined risk factors for the further course of 5-year survivors from osteosarcoma. It argues for large disease-oriented databases as well as for very long follow-up periods. Novel findings will most likely require innovative statistical models to analyze such cohorts.

Engineered biomaterial delivery strategies are used to reduce cardiotoxicity in osteosarcoma

Osteosarcoma (OS) is the most common malignant bone tumor in children and adolescents. Chemotherapy drugs play an integral role in OS treatment. Preoperative neoadjuvant chemotherapy and postoperative conventional adjuvant chemotherapy improve survival in patients with OS. However, the toxic side effects of chemotherapy drugs are unavoidable. Cardiotoxicity is one of the common side effects of chemotherapy drugs that cannot be ignored. Chemotherapy drugs affect the destruction of mitochondrial autophagy and mitochondria-associated proteins to cause a decrease in cardiac ejection fraction and cardiomyocyte necrosis, which in turn causes heart failure and irreversible cardiomyopathy. Biomaterials play an important role in nanomedicine. Biomaterials act as carriers to deliver chemotherapy drugs precisely around tumor cells and continuously release carriers around the tumor. It not only promotes anti-tumor effects but also reduces the cardiotoxicity of chemotherapy drugs. In this paper, we first introduce the mechanism by which chemotherapy drugs commonly used in OS cause cardiotoxicity. Subsequently, we introduce biomaterials for reducing cardiotoxicity in OS chemotherapy. Finally, we prospect biomaterial delivery strategies to reduce cardiotoxicity in OS.

Targeting Bone Tumor and Subcellular Endoplasmic Reticulum via Near Infrared II Fluorescent Polymer for Photodynamic-Immunotherapy to Break the Step-Reduction Delivery Dilemma

Specific localization of photosensitizers (PSs) to a certain organelle could result in targeted attack to cause greater trauma to cancer cells, eventually maximizing photodynamic therapy (PDT). However, currently, efficient and precise transportation of PSs via drug delivery to tumor cells and subcellular organelles is still challenging, due to a so-called step-reduction delivery dilemma (SRDD) which also threatens anticancer drug delivery to exert their efficacy. Herein, a cascade targeting near infrared II (NIR II) fluorescent nanoparticles (NPER/BO-PDT ) is designed that can target bone tumor first and then target the subcellular organelle of endoplasmic reticulum (ER). It is found that NPER/BO-PDT achieves the targeted accumulation of the bone tumor and then ER. NPER/BO-PDT generates reactive oxygen species (ROS) in the subcellular organelles of ER under near infrared light irradiation. The continuous ER stress by ROS promotes the release of more damage-associated molecular patterns, induces immunogenic cell death, stimulates the adaptive immune response, and further synergistically inhibits tumor growth, achieving the so-called photodynamic-immunotherapy. Overall, this study exemplifies a safe and efficient nano-drug delivery system for a bone and ER cascade targeting via delivery of PSs to break the SRDD and highlights potential clinical translation.

Epithelial to Mesenchymal Transition Relevant Subtypes with Distinct Prognosis and Responses to Chemo- or Immunotherapies in Osteosarcoma

Objective

Currently, clinical classification of osteosarcoma cannot accurately predict the survival outcomes and responses to chemo- or immunotherapies. Our goal was to classify osteosarcoma patients into clinical/biological subtypes based on EMT molecules.

Methods

This study retrospectively curated the RNA expression profiling of osteosarcoma patients from the TARGET and GSE21257 cohorts. Consensus clustering analyses were conducted in accordance with the expression profiling of prognostic EMT genes derived from univariate analyses. Immunological features were evaluated through immune cell infiltration, immune checkpoint expression, and activity of cancer immunity cycle. Drug sensitivity was estimated with the GDSC database. WGCNA approach was adopted to determine the EMT-derived genes. Following univariate analyses, a multivariate cox regression model was developed and externally verified. Predictive independency was evaluated with uni- and multivariate analyses. GSEA was presented to uncover relevant molecular mechanisms.

Results

Prognostic EMT genes across osteosarcoma patients were stratified into distinct subtypes, namely, subtypes A and B. Patients in subtype B presented desirable prognosis, high immune activation, and enhanced sensitivity to cisplatin. Meanwhile, patients in subtype A were more sensitive to gemcitabine. In total, 86 EMT-derived hub genes were determined, and an EMT score was conducted for osteosarcoma prognosis. Following external verification, this EMT score was reliably and independently predictive of patients' survival outcomes. Additionally, it was positively linked to steroid biosynthesis.

Conclusion

Overall, our findings proposed EMT-relevant molecular subtypes and signatures for predicting prognosis and therapeutic responses, contributing to personalized treatment and clinical implication for osteosarcoma.

Effects of butein on human osteosarcoma cell proliferation, apoptosis, and autophagy through oxidative stress

PURPOSE

Osteosarcoma (OS) is a primary malignant bone tumor, and the cure rate has stagnated in the past three decades. Butein, a plant polyphenol extracted from many herbs, has been proved to possess anti-tumor activity. However, the effect of butein on human OS and the underlying mechanisms remain to be elucidated.

MATERIALS AND METHODS

The OS cell line 143B was used. The effects of butein were evaluated through the cell proliferation assay, flow cytometry, florescence and transmission electron microscopy, and western blotting. All statistical analyses were performed using GraphPad Prism 7.0.

RESULTS

Butein was found to inhibit cell proliferation by causing G2/ M phase arrest in the 143B cells. In addition, butein suppressed the invasion of 143B cells upon IL-6 treatment. Additionally, we found that butein inhibited the invasion of 143B cells stimulated with IL-6 via the p-STAT3-MMP9 signaling pathway. Remarkably, butein triggered extrinsic and intrinsic apoptosis and autophagy of 143B cells. The process of autophagy may have tumor-supporting effects. Furthermore, butein induced oxidative stress as evidenced by ROS generation, increase in malondialdehyde (MDA) level, and decrease in GSH/GSSH ratio and GPX4 expression. N-acetylcysteine can reverse the change of ROS. Further experiments indicated apoptosis and autophagy could be attenuated by the N-acetyl-L-cysteine and c-Jun N-terminal kinase (JNK) inhibitor SP600125. Additionally, butein inhibited the Akt/mammalian target of rapamycin (mTOR) signaling pathway, and suppressed the Akt kinase activity increased apoptosis and autophagy.

CONCLUSION

Our results revealed butein induced apoptosis and autophagy by regulating oxidative stress, activating the JNK signaling pathway and blocking the Akt/mTOR signaling pathway in OS cells. Additionally, butein inhibited the invasion of 143B cells stimulated with IL-6 through the pSTAT3- MMP9 signaling pathway. In view of these results, butein may be a potential anti-tumor drug targeting osteosarcoma.