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.

Outcomes of 35 dogs with craniomaxillofacial osteosarcoma treated with stereotactic body radiation therapy.

Canine craniomaxillofacial osteosarcoma (OSA) is most commonly treated surgically; however, in cases where surgery is not feasible or non-invasive treatment is desired, stereotactic body radiation therapy (SBRT) may be elected for local tumour control. In this study, we evaluated 35 dogs treated with SBRT. Nine dogs (26%) had calvarial, seven (20%) had mandibular and 19 (54%) had maxillary OSA. Median time to first event (TFE) was 171 days, and overall median survival time (MST) was 232 days. Site-specific MSTs were 144 days for mandible, 236 days for calvarium and 232 days for maxilla (p = .49). Pulmonary metastatic disease was observed in 12/35 (34%) patients and was detected pre-SBRT in six dogs (17%) and post-SBRT in the remaining six dogs (17%). Eighteen adverse events post-SBRT were documented. Per veterinary radiation therapy oncology group criteria, five were acute (14%) and three were late (9%) grade 3 events. Neurological signs in two dogs were suspected to be early-delayed effects. Cause of death was local progression for 22/35 (63%) patients, metastasis for 9/35 (26%) patients and unknown for four. On univariate analysis, administration of chemotherapy was associated with a longer TFE (p = .0163), whereas volume of gross tumour volume was associated with a shorter TFE (p = .023). Administration of chemotherapy and five fractions versus single fraction of SBRT was associated with increased survival time (p = .0021 and .049). Based on these findings, a treatment protocol incorporating chemotherapy and five fractions of SBRT could be considered for dogs with craniomaxillofacial OSA electing SBRT with careful consideration of normal tissues in the field.

Therapeutic efficacy of an alpha-particle emitter labeled anti-GD2 humanized antibody against osteosarcoma-a proof of concept study.

PURPOSE: Current treatments for osteosarcoma (OS) have a poor prognosis, particularly for patients with metastasis and recurrence, underscoring an urgent need for new targeted therapies to improve survival. Targeted alpha-particle therapy selectively delivers cytotoxic payloads to tumors with radiolabeled molecules that recognize tumor-associated antigens. We have recently demonstrated the potential of an FDA approved, humanized anti-GD2 antibody, hu3F8, as a targeted delivery vector for radiopharmaceutical imaging of OS. The current study aims to advance this system for alpha-particle therapy of OS. METHODS: The hu3F8 antibody was radiolabeled with actinium-225, and the safety and therapeutic efficacy of the [225Ac]Ac-DOTA-hu3F8 were evaluated in both orthotopic murine xenografts of OS and spontaneously occurring OS in canines. RESULTS: Significant antitumor activity was proven in both cases, leading to improved overall survival. In the murine xenograft's case, tumor growth was delayed by 16-18 days compared to the untreated cohort as demonstrated by bioluminescence imaging. The results were further validated with magnetic resonance imaging at 33 days after treatment, and microcomputed tomography and planar microradiography post-mortem. Histological evaluations revealed radiation-induced renal toxicity, manifested as epithelial cell karyomegaly and suggestive polyploidy in the kidneys, suggesting rapid recovery of renal function after radiation damage. Treatment of the two canine patients delayed the progression of metastatic spread, with an overall survival time of 211 and 437 days and survival beyond documented metastasis of 111 and 84 days, respectively. CONCLUSION: This study highlights the potential of hu3F8-based alpha-particle therapy as a promising treatment strategy for OS.

Dose Distribution Degradation of Carbon-ion Radiotherapy Caused by Tumor Cell-specific Relative Biological Effectiveness of Osteosarcoma: A Simulation Study Using In Vitro Experimental Results.

BACKGROUND/AIM: Dose distributions of carbon-ion radiotherapy (C-ion RT) have been created with the relative biological effectiveness (RBE) of human salivary gland cells (HSG). However, no dose distributions have been created using various tumor cell-specific RBE values. Hence, we conducted in vitro experiments to determine the RBE of human osteosarcoma cells (U2OS) and used this RBE value (RBEU2OS) to calculate the dose distribution for C-ion RT. MATERIALS AND METHODS: To obtain RBE values for various linear energy transfer (LET) levels, we exposed U2OS cells to different doses of X-rays and varying doses and LET levels of C-ion beams (13, 30, 50, and 70 keV/µm). Subsequently, we converted the RBE of HSG (RBEHSG) to RBEU2OS in the treatment planning system and reconstructed the dose distribution for a typical osteosarcoma case. We performed a dose-volume histogram (DVH) analysis, evaluating the percentage of the minimum dose that covered 98%, 50%, and 2% (D98%, D50%, and D2%, respectively), as well as the homogeneity index [HI; calculated as (D2%-D98%)/D50%]. RESULTS: The RBEU2OS values for C-ion beams with LET of 13, 30, 50, and 70 keV/µm were 1.77, 2.25, 2.72, and 4.50, respectively. When comparing DVH parameters with the planning target volume, we observed the following values: D98%, D50%, D2%, and HI for RBEHSG were 64.1, 70.1, 72.4 Gy (RBE), and 0.12, respectively. For RBEU2OS, these values were 86.2, 95.0, 107.9 Gy (RBE), and 0.23, respectively. CONCLUSION: We utilized RBEU2OS to calculate the dose distribution of carbon ion radiotherapy, revealing potential degradation in dose distribution and particularly worsening of the HI.

Blue light photobiomodulation induced apoptosis by increasing ROS level and regulating SOCS3 and PTEN/PI3K/AKT pathway in osteosarcoma cells.

Blue light photobiomodulation (PBM) has attracted great attention in diminishing proliferation and inducing death of cancer cells recently. Osteosarcoma (OS) primarily occurring in children and adolescents, the limitations of drug resistance and limb salvage make it urgent to develop and identify new adjuvant therapeutic strategies. In this work, we attempted to research the anticancer effects and biological mechanisms of blue light PBM in human OS MG63 cells. The effects of various blue light parameters on MG63 cells indicated that suppressed cell proliferation and cell migration, induced cell apoptosis which are experimentally assessed using multiple assays including CCK, LDH, wound healing assay and Hoechst staining. Concurrently, the increases of ROS level and the inhibition of PI3K and AKT expression were identified under high-dose blue light PBM in MG63 cells. Meanwhile, SOCS3 is a major inducible anti-tumor molecule, we also found that blue light LED substantially promoted its expression. Thus, this study proposed that bule light PBM may be a hopeful therapeutic approach in OS clinical treatment in the future.

Extracorporeal irradiation in malignant bone tumors: Single institution experience and review of literature.

In the last couple of decades, the management of malignant bone tumor (MBT) has seen a sea change. With the advent in surgical technics, radiation therapy, and chemotherapy, it has moved from disabling amputation to limb salvage surgery. Extracorporeal irradiation (ECI) and re-implantation of resected bone is a useful method of limb salvage of MBTs. In our study, we analyzed and presented the results of 8 cases of MBTs treated with this modality. Between 2014 and 2017, 8 patients with primary MBT were enrolled for ECI technique who are meeting the eligibility criteria. Before taking the patient for ECI treatment, a multispecialty tumor board discussion was done for each patient. All of them received neo-adjuvant and adjuvant chemotherapy except the patients with histology of giant cell tumor. Following neoadjuvant chemotherapy bone excision surgery was performed, and the resected bone was taken for ECI with the dose of 50 Gray in a single fraction. After ECI, bone segment was re-implanted at osteotomy site in the same setting. After completion of adjuvant chemotherapy, the patients were then followed up for any sequelae, local and systemic control, ambulation, and functional outcome. Out of 8 patients, there were 5 males and 3 females with mean age of 22 (range 13-36). The involved bone was the tibia in 6 patients, ischium in 1 patient, and femur in 1 patient. Histopathologically, the malignancies included 3 osteosarcoma, 3 Giant cell tumor, 1 Ewing's sarcoma and 1 chondrosarcoma. At median follow-up of 12 months (range 6-26 months), local control rate was 87.5% and systemic control rate was 75%. Perioperative ECI and re-implantation is a useful, convenient, and inexpensive technique. The overall treatment time is reduced. The patient's own bone fits perfectly to the resection site with reduced risk of graft site infection. The risk of local recurrence due to tumor re-implantation is negligible with tumoricidal radiation doses of ECI, and it is usually associated with manageable sequelae. Recurrence rates are acceptable and salvageable with surgery.

The FBXO32/ATR/ATM axis acts as a molecular switch to control the sensitivity of osteosarcoma cells to irradiation through its regulation of EXO1 expression.

Osteosarcoma (OS) is the most common primary bone cancer in children and adolescents. In clinical treatments, the insensitivity of OS to conventional radiotherapy regimens significantly contributes to poor patient prognosis and survival. EXO1 is responsible for DNA repair pathways and telomere maintenance. Meanwhile, ATM and ATR are considered switches because they can regulate the expression of EXO1. However, their expression and interaction in OS cells under irradiation (IR) remain unclear. This study aims to investigate the roles of FBXO32, ATM, ATR and EXO1 in OS radiotherapy insensitivity and poor patient prognosis and explore potential pathogenic mechanisms. Bioinformatics is employed to analyse differential gene expression and correlations with prognosis in OS. Cell counting kit 8 assay, clone formation assay, and flow cytometry are used to evaluate cell survival and apopotosis under IR. Co-IP assay is used to detect protein‒protein interactions. Bioinformatics analysis reveals that EXO1 is closely related to survival, apoptosis and poor prognosis in OS. Silencing of EXO1 suppresses cell proliferation and increases the sensitivity of OS cells. Molecular biological experiments show that ATM and ATR act as switches to regulate EXO1 expression under IR. Higher expression of EXO1, which is closely correlated with IR insensitivity and poorer prognosis, might be used as a prognostic indicator for OS. Phosphorylated ATM enhances the expression of EXO1, and phosphorylated ATR induces the degradation of EXO1. More importantly, FBXO32 degrades ATR via ubiquitination in a time-dependent manner. Our data may provide a reference for future research in the mechanisms, clinical diagnosis, and treatment of OS.

Spectral computed tomography-guided radiotherapy of osteosarcoma utilizing BiOI nanosheets.

As an aggressive malignant bone tumor, osteosarcoma (OS) is usually found in children and adolescents. Computed tomography (CT) is an important tool for the clinical evaluation of osteosarcoma, but limits to low diagnostic specificity due to single parameters of traditional CT and modest signal-to-noise ratio of clinical iodinated contrast agents. As one kind of spectral CT, dual-energy CT (DECT), with the advantage of a provision of multi-parameter information, makes it possible to acquire the best signal-to-noise ratio image, accurate detection, as well as imaging-guided therapy of bone tumors. Hereby, we synthesized BiOI nanosheets (BiOI NSs) as a DECT contrast agent with superior imaging capability compared to iodine agents for clinical detection of OS. Meanwhile, the synthesized BiOI NSs with great biocompatibility is able to achieve effective radiotherapy (RT) by enhancing X-ray dose deposition at the tumor site, leading to DNA damage, which in turn inhibits tumor growth. This study offers a promising new avenue for DECT imaging-guided treatment of OS. STATEMENT OF SIGNIFICANCE: Osteosarcoma (OS) is a common primary malignant bone tumor. Traditional surgical procedures and conventional CT scans are often used for the treatment and monitoring of OS, but the effects are generally unsatisfactory. In this work, BiOI nanosheets (NSs) was reported for dual-energy CT (DECT) imaging-guided OS radiotherapy. The powerful and constant X-ray absorption of BiOI NSs at any energy guarantees excellent enhanced DECT imaging performance, allowing detailed visualization of OS through images with a better signal-to-noise ratio and guiding radiotherapy process. The deposition of X-rays could be greatly enhanced by Bi atoms to induce serious DNA damage in radiotherapy. Taken together, the BiOI NSs for DECT-guided radiotherapy will greatly improve the current treatment status of OS.

Exploring the Patient Perspective of Bone Sarcoma Survivors Who Have Undergone Particle Radiotherapy Abroad.

BACKGROUND/AIM: Sarcoma patients' experiences of their health-related quality of life and late effects following particle therapy are sparse. Such knowledge is essential to optimize treatment compliance and follow-up care related to this rapidly developing, but still centralized treatment modality. PATIENTS AND METHODS: This qualitative study has an explorative design and applies a phenomenological and hermeneutical approach based on semi-structured interviews with 12 bone sarcoma patients who had undergone particle therapy abroad. The data were interpreted using thematic analysis. RESULTS: Several of the participants called for more information about how the treatment would be carried out, its acute side effects and late complications. Most participants had positive experiences from the treatment and their stay abroad, but several struggled with late effects and other challenges. Themes that emerged from the analysis were "importance of being prepared", "treatment and stay abroad", "basically healthy, but with health problems and challenges". CONCLUSION: Oncologists who inform and refer patients to particle therapy abroad must have sufficient experience of this treatment modality, prognoses, acute side effects, and late complications. Findings derived from this study may improve treatment preparation and compliance, enhance understanding of individual patient challenges to reduce stress and worry, and lead to better follow-up care and consequently quality of life of this selected group of bone sarcoma patients.

3D bioprinted osteosarcoma model for experimental boron neutron capture therapy (BNCT) applications: Preliminary assessment.

Osteosarcoma is the most frequently primary malignant bone tumor characterized by infiltrative growth responsible for relapses and metastases. Treatment options are limited, and a new therapeutic option is required. Boron neutron capture therapy (BNCT) is an experimental alternative radiotherapy able to kill infiltrative tumor cells spearing surrounding healthy tissues. BNCT studies are performed on 2D in vitro models that are not able to reproduce pathological tumor tissue organization or on in vivo animal models that are expensive, time-consuming and must follow the 3R's principles. A 3D in vitro model is a solution to better recapitulate the complexity of solid tumors meanwhile limiting the animal's use. Objective of this study is to optimize the technical assessment for developing a 3D in vitro osteosarcoma model as a platform for BNCT studies: printing protocol, biomaterial selection, cell density, and crosslinking process. The best parameters that allow a fully colonized 3D bioprinted construct by rat osteosarcoma cell line UMR-106 are 6 × 106 cells/ml of hydrogel and 1% CaCl2 as a crosslinking agent. The proposed model could be an alternative or a parallel approach to 2D in vitro culture and in vivo animal models for BNCT experimental study.

Effect of stimulator of interferon genes (STING) signaling on radiation-induced chemokine expression in human osteosarcoma cells.

Cancer cell-intrinsic mechanisms affecting radiation immunomodulation could be exploited to optimize systemic effects of localized radiation. Radiation-induced DNA damage is sensed by cyclic GMP-AMP synthase (cGAS), which ultimately activates stimulator of interferon (IFN) genes (STING). Resultant expression of soluble mediators such as CCL5 and CXCL10 can facilitate recruitment of dendritic cells and immune effector cells into the tumor. The primary objectives of this study were to determine the baseline expression levels of cGAS and STING in OSA cells and evaluate the dependence of OSA cells on STING signaling for eliciting radiation-induced expression of CCL5 and CXCL10. cGAS and STING expression, and CCL5/CXCL10 expression in control cells, STING-agonist treated cells, and cells treated with 5 Gy ionizing radiation were assessed utilizing RTqPCR, Western blot, and ELISA. U2OS and SAOS-2 OSA cells were deficient in STING relative to human osteoblasts (hObs), while SAOS-2-LM6 and MG63 OSA cells expressed equivalent amounts of STING compared to hObs. A dependence on baseline or induced STING expression was observed for STING-agonist, and radiation-induced, expression of CCL5 and CXCL10. This finding was confirmed by performing siRNA knockdown of STING in MG63 cells. These results show that STING signaling is necessary for radiation-induced expression of CCL5 and CXCL10 in OSA cells. Additional studies are necessary to determine whether STING expression in OSA cells in vivo alters immune cell infiltrates after radiation exposure. These data may also have implications for other potentially STING-dependent characteristics such as resistance to oncolytic virus cytotoxicity.

Three-dimensional-printed MPBI@ß-TCP scaffold promotes bone regeneration and impedes osteosarcoma under near-infrared laser irradiation.

Beta-tricalcium phosphate (ß-TCP) is considered as one of the most promising biomaterials for bone reconstruction. This study generated a functional molybdenum disulfide (MoS2 )/polydopamine (PDA)/-bone morphogenetic protein 2 (BMP2)-insulin-like growth factor-1 (IGF-1) coating on the ß-TCP scaffold and analyzed the outcomes. The MoS2 /PDA-BMP2-IGF-1@ß-TCP (MPBI@ß-TCP) scaffold was prepared by 3D printing and physical adsorption, followed by characterization to validate its successful construction. The in vitro osteogenic effect of the MPBI@ß-TCP scaffold was evaluated. It was found that MPBI@ß-TCP augmented the adhesion, diffusion and proliferation of mesenchymal stem cells (MSCs). The alkaline phosphatase (ALP) activity, collagen secretion and extracellular matrix (ECM) mineralization along with the expression of Runx2, ALP and OCN were also enhanced in the presence of MPBI@ß-TCP. Additionally, MPBI@ß-TCP stimulated endothelial cells to secrete VEGF and promoted capillary-like tubule formation. We then confirmed the biocompatibility of MPBI@ß-TCP to macrophages and its anti-inflammatory effects. Furthermore, under near-infrared (NIR) laser irradiation, MPBI@ß-TCP produced photothermal effect to not only kill MG-63 osteosarcoma cells, but also enhance bone regeneration in vivo with biosafety. Overall, this work demonstrates that 3D-printed MPBI@ß-TCP with enhanced osteogenic activity under NIR laser irradiation has a vast potential in the field of tissue defects.

Factors affecting the incorporation of extracorporeally irradiated autograft for the treatment of bone tumours-a retrospective analysis from a tertiary referral centre.

PURPOSE: Re-implantation of the tumor bearing autograft following extracorporeal radiation therapy (ECRT) has been established as an oncologically safe biological reconstruction technique following resection of bone sarcomas. However, factors affecting the ECRT graft-host bone incorporation have not been fully investigated. An insight into the factors that influence graft incorporation can circumvent the complications and increase graft survival. METHODS: A total of 96 osteotomies in 48 patients with intercalary resections of primary extremity bone sarcomas (mean age 15.8 years, mean follow-up 42.1 months) were analyzed retrospectively for factors ECRT autograft-host bone union. RESULTS: On univariate analysis, age < 20 years, metaphyseal osteotomy site, V-shaped diaphyseal osteotomy, and use of additional plate at diaphyseal osteotomy had a significantly faster time to union, while gender, tumour type, bone involved, resection length, chemotherapy, type of fixation, and use of intra-medullary fibula did not influence union time. In multivariate analysis, V-shaped diaphyseal osteotomy and use of additional plate at diaphyseal ostetomy were the independent factors with favourable time to union. None of the analyzed factors was found to have a significant effect on the union rate. The major complications were non-union in 11.4% patients, graft failure in 2.1%, infection in 12.5%, and soft tissue local recurrences in 14.5% patients. CONCLUSION: Modified diaphyseal osteotomy and augmentation of the stability of the reconstruction using additional small plates enhance the incorporation of ECRT autograft.

Tantalum-Zirconium Co-Doped Metal-Organic Frameworks Sequentially Sensitize Radio-Radiodynamic-Immunotherapy for Metastatic Osteosarcoma.

Due to radiation resistance and the immunosuppressive microenvironment of metastatic osteosarcoma, novel radiosensitizers that can sensitize radiotherapy (RT) and antitumor immunity synchronously urgently needed. Here, the authors developed a nanoscale metal-organic framework (MOF, named TZM) by co-doping high-atomic elements Ta and Zr as metal nodes and porphyrinic molecules (tetrakis(4-carboxyphenyl)porphyrin (TCPP)) as a photosensitizing ligand. Given the 3D arrays of ultra-small heavy metals, porous TZM serves as an efficient attenuator absorbing X-ray energy and sensitizing hydroxyl radical generation for RT. Ta-Zr co-doping narrowed the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap and exhibited close energy levels between the singlet and triplet photoexcited states, facilitating TZM transfer energy to the photosensitizer TCPP to sensitize singlet oxygen (1 O2 ) generation for radiodynamic therapy (RDT). The sensitized RT-RDT effects of TZM elicit a robust antitumor immune response by inducing immunogenic cell death, promoting dendritic cell maturation, and upregulating programmed cell death protein 1 (PD-L1) expression via the cGAS-STING pathway. Furthermore, a combination of TZM, X-ray, and anti-PD-L1 treatments amplify antitumor immunotherapy and efficiently arrest osteosarcoma growth and metastasis. These results indicate that TZM is a promising radiosensitizer for the synergistic RT and immunotherapy of metastatic osteosarcoma.

Development of nomogram and discussion of radiotherapy effect for osteosarcoma survival.

This study aimed to develop a predictive system for prognostic evaluation of osteosarcoma patients. We obtained osteosarcoma sample data from 1998 to 2016 using SEER*Stat software version 8.3.8, and established a multivariable Cox regression model using R-4.0.3 software. Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The diagnosis of the model was completed through influential cases, proportionality, and multicollinearity. The predictive ability of the model was tested using area under the curve (AUC), calibration curves, and Brier scores. Finally, the bootstrap method was used to internally verify the model. In total, data from 3566 patients with osteosarcoma were included in this study. The multivariate Cox regression model was used to determine the independent prognostic variables. A nomogram and Kaplan-Meier survival curve were established. The AUC and Brier scores indicated that the model had a good predictive calibration. In addition, we found that the radiotherapy appears to be a risk factor of patients with osteosarcoma and made a discussion. We developed a prognostic evaluation system for patients with osteosarcoma for 1-, 3-, and 5-year overall survival with good predictive ability using sample data extracted from the SEER database. This has important clinical significance for the early identification and treatment of high-risk groups of osteosarcoma patients.

Configuration of pathologic fractures in dogs with osteosarcoma following stereotactic body radiation therapy: A retrospective analysis.

For some cases of canine appendicular osteosarcoma (OSA), limb-sparing treatment options are often desired, one of which is stereotactic body radiation therapy (SBRT). A major complication of SBRT is fracture of the irradiated bone at the site of treatment. The present study evaluated 127 appendicular OSA sites in 122 dogs treated with SBRT to identify the most common pathologic fracture locations and configurations. A total of 50 tumours experienced a pathologic fracture, and 38 had imaging sufficient to identify fracture configuration. The distal tibia was more likely to develop a fracture than other sites. Multiple types of fracture configuration (transverse, oblique, spiral and comminuted) were observed. The distal radius was significantly more likely to develop a transverse fracture than other sites. Documentation of fracture location and configuration leads to the identification of the forces contributing to fracture occurrence, since each configuration is a result of different forces acting on each affected bone. Such knowledge is imperative for the development of new approaches to diminish the occurrence of pathologic fractures.

Carotenoid-Enriched Nanoemulsions and γ-Rays Synergistically Induce Cell Death in a Novel Radioresistant Osteosarcoma Cell Line.

We previously demonstrated that SAOS human osteosarcoma cells, incubated with carotenoid-enriched nanoemulsions (CEN), activated a nonprotective form of autophagy and delayed cell proliferation. The present work focuses on the biological effects of CEN on a derivative of SAOS cells named SAOS400, recently described for their radiation resistance and higher expression of therapy-induced senescence (TIS) markers. SAOS400 cells, incubated with CEN, activated a "cytostatic" form of autophagy confirmed by cell cycle arrest in the G2/M phase and increased expression of autophagic proteins. Treatment of SAOS400 cells with CEN also resulted in decreased expression of the senescence marker p16INK4. However, when SAOS400 cells were γ-irradiated in combination with CEN, the threshold for cell death was reached (>60% after 96 h). We showed that this type of cell death corresponded to 'cytotoxic' or 'lethal' autophagy and that the combined treatment of CEN plus γ-rays was synergistic, with the combination index < 1. Since CEN contained ß-carotene, the pure compound was used in SAOS400 cells at the same concentration present in CEN and up to 10 times higher. However, no radio-sensitizing effect of ß-carotene was observed, suggesting that the biological effect of CEN was due to less abundant but more bioactive molecules, or to the synergistic activity of multiple components present in the extracts, confirming the functional pleiotropy of natural extracts enriched in bioactive molecules.

Efficacy and safety of carbon ion radiotherapy for bone sarcomas: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to systematically evaluate and conduct a meta-analysis of the efficacy and safety of carbon ion radiotherapy for bone sarcomas. METHODS: We searched for articles using the PubMed, Embase, Cochrane Library, and the Web of Science databases from their inception to January 12, 2022. Two researchers independently screened the literature and extracted data based on the inclusion and exclusion criteria. Statistical analyses were performed using STATA version 14.0. RESULTS: We searched for 4378 candidate articles, of which 12 studies were included in our study according to the inclusion and exclusion criteria. Of the 897 BSs patients who received carbon ion radiotherapy in the studies, 526 patients had chordoma, 255 patients had chondrosarcoma, 112 patients had osteosarcoma, and 4 patients had other sarcomas. The local control rate at 1, 2, 3, 4, 5, and 10 years in these studies were 98.5% (95% confidence interval [CI] = 0.961-1.009, I2 = 0%), 85.8% (95% CI = 0.687-1.030, I2 = 91%), 86% (95% CI = 0.763-0.957, I2 = 85.3%), 91.1% (95% CI = 0.849-0.974), 74.3% (95% CI = 0.666-0.820, I2 = 85.2%), and 64.7% (95% CI = 0.451-0.843, I2 = 95.3%), respectively. The overall survival rate at 1, 2, 3, 4, 5, and 10 years in these studies were 99.9% (95% CI = 0.995-1.004, I2 = 0%), 89.6% (95% CI = 0.811-0.980, I2 = 96.6%), 85% (95% CI = 0.750-0.950, I2 = 89.4%), 92.4% (95% CI = 0.866-0.982), 72.7% (95% CI = 0.609-0.844, I2 = 95.3%), and 72.1% (95% CI = 0.661-0.781, I2 = 46.5%), respectively. Across all studies, the incidence of acute and late toxicities was mainly grade 1 to grade 2, and grade 1 to grade 3, respectively. CONCLUSION: As an advanced radiotherapy, carbon ion radiotherapy is promising for patients with bone sarcomas that are unresectable or residual after incomplete surgery. The data indicated that carbon ion radiotherapy was safe and effective for bone sarcomas, showing promising results for local control, overall survival, and lower acute and late toxicity. PROSPERO REGISTRATION NUMBER: CRD42021258480.