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Purpose: The overall survival rate for metastatic osteosarcoma hovers around 20%. Responses to second-line chemotherapy, targeted therapies, and immunotherapies have demonstrated limited efficacy in metastatic osteosarcoma. Our objective is to validate differentially expressed genes and signaling pathways between non-metastatic and metastatic osteosarcoma, employing single-cell RNA sequencing (scRNA-seq) and additional functional investigations. We aim to enhance comprehension of metastatic mechanisms and potentially unveil a therapeutic target., Methods: scRNA-seq was performed on two primary osteosarcoma lesions (1 non-metastatic and 1 metastatic). Seurat package facilitated dimensionality reduction and cluster identification. Copy number variation (CNV) was predicted using InferCNV. CellChat characterized ligand-receptor-based intercellular communication networks. Differentially expressed genes underwent GO function enrichment analysis and GSEA. Validation was achieved through the GSE152048 dataset, which identified PDGFD-PDGFRB as a common ligand-receptor pair with significant contribution. Immunohistochemistry assessed PDGFD and PDGFRB expression, while multicolor immunofluorescence and flow cytometry provided insight into spatial relationships and the tumor immune microenvironment. Kaplan-Meier survival analysis compared metastasis-free survival and overall survival between high and low levels of PDGFD and PDGFRB. Manipulation of PDGFD expression in primary osteosarcoma cells examined invasion abilities and related markers., Results: Ten clusters encompassing osteoblasts, osteoclasts, osteocytes, fibroblasts, pericytes, endothelial cells, myeloid cells, T cells, B cells, and proliferating cells were identified. Osteoblasts, osteoclasts, and osteocytes exhibited heightened CNV levels. Ligand-receptor-based communication networks exposed significant fibroblast crosstalk with other cell types, and the PDGF signaling pathway was activated in non-metastatic osteosarcoma primary lesion. These results were corroborated by the GSE152048 dataset, confirming the prominence of PDGFD-PDGFRB as a common ligand-receptor pair. Immunohistochemistry demonstrated considerably greater PDGFD expression in non-metastatic osteosarcoma tissues and organoids, correlating with extended metastasis-free and overall survival. PDGFRB expression showed no significant variation between non-metastatic and metastatic osteosarcoma, nor strong correlations with survival times. Multicolor immunofluorescence suggested co-localization of PDGFD with PDGFRB. Flow cytometry unveiled a highly immunosuppressive microenvironment in metastatic osteosarcoma. Manipulating PDGFD expression demonstrated altered invasive abilities and marker expressions in primary osteosarcoma cells from both non-metastatic and metastatic lesions., Conclusions: scRNA-seq illuminated the activation of the PDGF signaling pathway in primary lesion of non-metastatic osteosarcoma. PDGFD displayed an inhibitory effect on osteosarcoma metastasis, likely through the suppression of the EMT signaling pathway., (© 2024. The Author(s).)

Purpose: We investigated the safety and preliminary efficacy of anti-PD-L1 antibody (ZKAB001) as maintenance therapy for localized patients with high-grade osteosarcoma to reduce the risk of recurrence and metastasis., Patients and Methods: This open-label Phase I/II study was divided into dose-escalation Phase I and expansion Phase II. Phase I used a 3+3 design with ZKAB001 at three escalating doses ranging: 5, 10, 15 mg/kg every 2 weeks in 9 patients with localized high-grade osteosarcoma and Phase II tested 10 mg/kg in 12 patients for up to 24 cycles. Primary endpoints were safety and tolerability assessed using CTCAE4.0.3., Results: Between October 2018 and 2019, 21 eligible patients were enrolled and accepted ZKAB001 treatment: 9 in the dose-escalation phase, and 12 in expansion phase. Six patients with disease progression withdrew from this study and follow-up is ongoing. The MTD was not defined in Phase I. All doses had a manageable safety profile. The recommended dose in Phase II was set at 10 mg/kg. Most frequent immune-related adverse events were thyroiditis (76.2%) and dermatitis (42.9%). Only 1 (4.8%) of 21 patients had a Grade 3 skin rash. The median 3-year event-free survival (EFS) and overall survival (OS) were not established; however, 24-month EFS was 71.4% (95% confidence interval, 47.2-86.0) and 2-year OS was 100%. Preliminary efficacy data showed EFS benefits in patients with PD-L1 positive or an MSI-H sub-population., Conclusions: Switching to maintenance using ZKAB001 showed an acceptable safety profile and provided preliminary evidence of clinical activity in localized patients with osteosarcoma., (©2022 American Association for Cancer Research.)

Osteosarcoma is the most frequent primary bone tumor with poor prognosis. Through RNA-sequencing of 100,987 individual cells from 7 primary, 2 recurrent, and 2 lung metastatic osteosarcoma lesions, 11 major cell clusters are identified based on unbiased clustering of gene expression profiles and canonical markers. The transcriptomic properties, regulators and dynamics of osteosarcoma malignant cells together with their tumor microenvironment particularly stromal and immune cells are characterized. The transdifferentiation of malignant osteoblastic cells from malignant chondroblastic cells is revealed by analyses of inferred copy-number variation and trajectory. A proinflammatory FABP4 + macrophages infiltration is noticed in lung metastatic osteosarcoma lesions. Lower osteoclasts infiltration is observed in chondroblastic, recurrent and lung metastatic osteosarcoma lesions compared to primary osteoblastic osteosarcoma lesions. Importantly, TIGIT blockade enhances the cytotoxicity effects of the primary CD3 + T cells with high proportion of TIGIT + cells against osteosarcoma. These results present a single-cell atlas, explore intratumor heterogeneity, and provide potential therapeutic targets for osteosarcoma.

Osteosarcoma (OS) is the most common primary bone malignancy with high rates of recurrence and metastasis. OS often spreads to lungs, an optimized model for studying lung metastatic OS cells may help develop potential therapies for patients with lung metastasis. Here we firstly report an organoid culture system for lung metastatic OS tissues. We provided a fully described formula that was required for establishing lung metastatic OS organoids (OSOs). Using this protocol, the lung OSOs were able to be maintained and serially propagated for at least six months; the OSOs can also be generated from cryopreserved patient samples without damaging the morphology. The patient-derived lung OSOs retained the cellular morphology and expression of OS markers (Vimentin and Sox9) that recapitulate the histological features of the human OS. The microenvironment of primary lung metastatic OSOs preserved a similar T cell distribution with the human lung OS lesions; this provided a possible condition to explore how OS cells may react to immunotherapy. OSOs established from this protocol can be further utilized for studying various aspects of OS biology (e.g., tumorigenesis and drug screen/discovery) for precision medicine.

Osteosarcoma (OS) is a primary malignant bone neoplasm with high frequencies of tumor metastasis and recurrence. Although the Akt/PKB signaling pathway is known to play key roles in tumorigenesis, the roles of cyclin-dependent kinase-like 3 (CDKL3) in OS progression remain largely elusive. We have demonstrated the high expression levels of CDKL3 in OS human specimens and comprehensively investigated the role of CDKL3 in promoting OS progression both in vitro and in vivo. We found that CDKL3 regulates Akt activation and its downstream effects, including cell growth and autophagy. The up-regulation of CDKL3 in OS specimens appeared to be associated with Akt activation and shorter overall patient survival ( P = 0.003). Our findings identify CDKL3 as a critical regulator that stimulates OS progression by enhancing Akt activation. CDKL3 represents both a biomarker for OS prognosis, and a potential therapeutic target in precision medicine by targeting CDKL3 to treat Akt hyper-activated OS., (© 2020 He et al.)

Systemic inflammation responses have been associated with cancer development and progression. C-reactive protein (CRP), Glasgow prognostic score (GPS), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), lymphocyte-monocyte ratio (LMR), and neutrophil-platelet score (NPS) have been shown to be independent risk factors in various types of malignant tumors. This retrospective analysis of 162 osteosarcoma cases was performed to estimate their predictive value of survival in osteosarcoma. All statistical analyses were performed by SPSS statistical software. Receiver operating characteristic (ROC) analysis was generated to set optimal thresholds; area under the curve (AUC) was used to show the discriminatory abilities of inflammation-based scores; Kaplan-Meier analysis was performed to plot the survival curve; cox regression models were employed to determine the independent prognostic factors. The optimal cut-off points of NLR, PLR, and LMR were 2.57, 123.5 and 4.73, respectively. GPS and NLR had a markedly larger AUC than CRP, PLR and LMR. High levels of CRP, GPS, NLR, PLR, and low level of LMR were significantly associated with adverse prognosis (P < 0.05). Multivariate Cox regression analyses revealed that GPS, NLR, and occurrence of metastasis were top risk factors associated with death of osteosarcoma patients.

We performed a retrospective analysis of 32 metastatic osteosarcoma cases to examine the prognostic value of the plasma D-dimer level. We assessed the D-dimer level before second-line chemotherapy (D1) and the D-dimer level after two cycles of second-line chemotherapy (D2). The change in D-dimer level (ΔD) was defined as D2 minus D1. The overall survival (OS) of patients with a high D1 was significantly shorter than those with a low D1 (median OS, 4.7 vs. 16.2 months, P=0.001). Similar results were observed for the D2 (median OS, 4.7 vs. 8.6 months, P=0.033). Multivariable analysis demonstrated that a high D1 (hazard ratio, 3.375; 95% confidence interval, 1.133-10.053; P=0.029) was an unfavorable independent prognostic factor. The mean D2 of 11 patients with stable disease decreased by 0.69 mg/mL compared to the D1 (P = 0.016). The mean D2 increased by 1.47 mg/mL compared to the D1 in 21 patients with progressive disease (P = 0.004). The data suggest that D-dimer may serve as a prognostic biomarker for metastatic osteosarcoma patients treated with second-line chemotherapy.

CD133 and CD44 are commonly used markers of cancer stem cells (CSCs), which are characterized by their ability for self-renewal and tumorigenicity. However, the clinical value and significance of CD133 and CD44 in lung metastasis of osteosarcoma (OS) remains controversial. The purpose of this study was to investigate whether CD133(+) CD44(+) cells mediates the metastasis of OS. We identified the CD133(+) CD44(+) cells in lung metastatic lesions and OS cell lines, and next demonstrated CD133(+) CD44(+) cells were more aggressive in sphere formation, migration and invasiveness compared with CD133(+) CD44(-) , CD133(-) CD44(+) , or CD133(-) CD44(-) cells. We finally sorted the CD133(+) CD44(+) and CD133(-) CD44(-) cells from Saos-2 cell lines, after intratibial xenograft in nude mice, these cells developed primary tumors, and CD133(+) CD44(+) cells are more potential to form lung metastatic tumors. Thus we concluded that CD133(+) CD44(+) cells may mediate in the lung metastasis of OS., (© 2015 Wiley Periodicals, Inc.)

Osteosarcoma is the most common type of malignant bone tumor in children and adolescents. Numerous patients are unable to be cured due to the development of resistance of the osteosarcoma cells to chemotherapeutic drugs. Therefore, reversion of drug resistance is urgently required for the treatment of osteosarcoma. Arsenic trioxide (As2O3) is an active ingredient in Traditional Chinese Medicine, but the therapeutic potential of As2O3 in osteosarcoma remains largely unexplored. The current study investigated the effects of As2O3 on MG63 osteosarcoma cells using a cell proliferation assay, flow cytometric analysis of the cell cycle and cell apoptosis, reverse transcription polymerase chain reaction to detect stathmin mRNA expression levels and western blot analysis to detect the stathmin protein expression levels. As2O3 and doxorubicin (ADM) combination treatment markedly inhibited cell proliferation in ADM-resistant MG63 (MG63/dox) osteosarcoma cells, clearly induced G2/M phase cell cycle arrest and increased the number of apoptotic MG63/dox cells. Furthermore, stathmin expression was found to be downregulated in MG63/dox cells and was sensitive to ADM treatment. Additional investigation revealed that the downregulation of stathmin expression in MG63/dox cells by stathmin small interfering RNA significantly enhanced the reversion of ADM resistance in MG63/dox by As2O3. The data indicated that As2O3 reversed ADM resistance in MG63/dox cells through downregulation of stathmin and may be a potential drug for the treatment of ADM-resistant osteosarcoma.

Background: The prognoses for patients with relapsed and refractory osteosarcoma are poor and the optimal treatment strategy is still to be defined. We conducted this retrospective study to compare the feasibility and efficacy of pirarubicin-based chemotherapy with gemcitabine-docetaxel combination regimens for the salvage of these patients., Methods: The clinical data of 75 patients who received pirarubicin-based (n = 52) or gemcitabine-docetaxel (n = 23) chemotherapy as a second-line treatment for relapsed and refractory osteosarcoma between January 2005 and September 2011were reviewed retrospectively. Tumor response was evaluated every two chemotherapy cycles by computed tomography/magnetic resonance imaging (CT/MRI) scans using the Response Evaluation Criteria in Solid Tumors. Progression-free survival and overall survival (OS) were evaluated by Kaplan-Meier analysis. Toxicity was examined according to the National Cancer Institute Toxicity Criteria grading system., Results: Patient characteristics were well balanced in the two groups. The response rate was 25.0 % in patients who received pirarubicin-based chemotherapy, while it was 13.0 % in the gemcitabine-docetaxel group. Moreover, the median OS was longer in the pirarubicin-based chemotherapy group (14.0 vs. 9.0 months, P < 0.05), especially in the pirarubicin-ifosfamide (14.0 months) and pirarubicin-cisplatin (15.0 months) subgroups. The incidence of grade 3-4 neutropenia was higher in the gemcitabine-docetaxel group (5.8 vs. 43.5 %, P < 0.05); other grade 3-4 toxicities were comparable in the two groups., Conclusions: In our experience, pirarubicin-based chemotherapy was comparable with gemcitabine-docetaxel as a second-line treatment for relapsed and refractory osteosarcoma, and it even seemed to show greater efficacy, with milder toxicity. Further studies, especially prospective clinical trials, focusing on pirarubicin-based treatments for relapsed and refractory osteosarcoma patients should be strongly considered.

Background: Cell-based immunotherapy shows the therapeutic potential in sarcomas, in addition to angiogenesis-targeted tyrosine kinase inhibitor (TKI) and immune checkpoint inhibitor (ICI). Multi-antigen stimulated cell therapy-I (MASCT-I) technology is a sequential immune cell therapy for cancer, which composes of multiple antigen-loaded dendritic cell (DC) vaccines followed by the adoptive transfer of anti-tumor effector T-cells. Methods: In this phase 1 study, we assessed MASCT-I plus camrelizumab (an ICI against PD-1) and apatinib (a highly selective TKI targeting VEGFR2) in patients with unresectable recurrent or metastatic bone and soft-tissue sarcoma after at least one line of prior systemic therapy. One MASCT-I course consisted of 3 DC subcutaneous injections, followed by 3 active T cell infusions administered 18–27 days after each DC injection. In schedule-I group, 3 DC injections were administered with a 28-day interval in all courses; in schedule-II group, 3 DC injections were administered with a 7-day interval in the first course and with a 28-day interval thereafter. All patients received intravenous camrelizumab 200 mg every 3 weeks and oral apatinib 250 mg daily. Results: From October 30, 2019, to August 12, 2021, 19 patients were enrolled and randomly assigned to schedule-I group (n = 9) and schedule-II group (n = 10). Of the 19 patients, 11 (57.9%) experienced grade 3 or 4 treatment-related adverse events. No treatment-related deaths occurred. Patients in schedule-II group showed similar objective response rate (ORR) with those in schedule-I group (30.0% versus 33.3%) but had higher disease control rate (DCR; 90.0% versus 44.4%) and longer median progression-free survival (PFS; 7.7 versus 4.0 months). For the 13 patients with soft-tissue sarcomas, the ORR was 30.8%, DCR was 76.9%, and median PFS was 12.9 months; for the 6 patients with osteosarcomas, the ORR was 33.3%, the DCR was 50.0%, and median PFS was 5.7 months. Conclusions: Overall, MASCT-I plus camrelizumab and apatinib was safe and showed encouraging efficacy in advanced bone and soft-tissue sarcoma, and schedule-II administration method was recommended. Trial registration: ClinicalTrials.gov, NCT04074564. [ABSTRACT FROM AUTHOR]

Purpose: The options for the second-line treatment of metastatic osteosarcoma are still limited. Anlotinib is a multi-kinase inhibitor which has shown promising efficacy and good tolerability in various cancer types. This retrospective study was conducted to evaluate the efficacy and safety of anlotinib combined with gemcitabine/docetaxel (GD) in patients with metastatic osteosarcoma who have failed first-line chemotherapy. Patients and Methods: The data of patients who received anlotinib combined with GD or GD were collected. The primary endpoint was progression-free survival. Secondary endpoints included objective response rate and safety. Results: From July 2013 to November 2020, a total of 32 patients were enrolled, 13 received anlotinib combined with GD and 19 received GD. Median PFS was 9.0 months (95% CI 6.7– 39.1) in the combination group and 5.0 months (95% CI 1.2– 6.7) in the chemotherapy group. ORR were 38.4% and 15.8%, DCR were 69.2% and 38.1% in the combination and chemotherapy group, respectively. The most common adverse events included fatigue (78.9% in the combination group vs 69.2% in the chemotherapy group), hypertension (46.2% vs 10.5%), diarrhea (38.5% vs 21.1%), hypothyroidism (38.5% vs 15.8%), neutropenia (23.1% vs 36.8%) and AST elevation (30.8% vs 21.1%). The most common grade 3 or worse adverse events included hand-foot reaction (7.7% vs 5.3%), hypothyroidism (15.4% vs 0), neutropenia (0 vs 10.5%). Conclusion: The combination of anlotinib and GD showed favorable efficacy with manageable toxicities compared with GD in the second-line treatment for metastatic osteosarcoma. This combination therapy deserves further investigations in patients with osteosarcoma. [ABSTRACT FROM AUTHOR]

Purpose: This retrospective study explored the clinical value of the plasma D-dimer level in osteosarcoma. Materials and Methods: We measured the plasma D-dimer level before neoadjuvant chemotherapy (D0) and the plasma D-dimer level after four courses of neoadjuvant chemotherapy (D1) in 103 patients with stage-IIB high-grade osteosarcoma of the limb. The change in the D-dimer level (ΔD) was defined as D1 minus D0. The chi-square test was used to compare categorical variables. Analyses of receiver operating characteristic (ROC) curves were undertaken to determine the optimal cutoff points for D0, D1, and ΔD. The area under the ROC (AUC) of D0, D1, and ΔD was calculated to evaluate their discriminatory abilities in monitoring the response to neoadjuvant chemotherapy (tumor necrosis). Survival curves were generated according to Kaplan–Meier analyses and compared using the Log rank test. Univariate analyses and multivariate analyses were carried out to determine independent prognostic factors. Results: Kaplan–Meier curves showed that a high D-dimer level at D0 and tumor diameter ≥ 8 cm were associated significantly with worse overall survival (OS) (P< 0.05). Multivariate Cox regression analyses revealed a high D-dimer level at D0 (hazard ratio, 3.92; 95% confidence interval, 1.756– 5.804; P=0.000) was an independent unfavorable prognostic factor. The chi-square test showed ΔD to be associated significantly with tumor necrosis. Analyses of ROC curves showed the D-dimer level at D0 and ΔD had better ability compared to that at D1 to discriminate the response to neoadjuvant chemotherapy. Conclusion: The D-dimer level was correlated with the prognosis and response to chemotherapy in patients with stage-IIB high-grade osteosarcoma of the limb. The D-dimer level may serve as a risk factor of the response to chemotherapy and prognosis of localized osteosarcoma. [ABSTRACT FROM AUTHOR]

Purpose: The aims of this study were to determine the effect of curcumin on osteosarcoma (OS) cells due to inactivation of the p-JAK2/p-STAT3 pathway and evaluate the prognostic value of this pathway in OS. Materials and methods: We exposed a human OS cell line (MG-63) to different concentrations of curcumin. Then, we characterized the effects on MG-63 cells using assays (cell viability, colony formation, cell cycle, wound healing, invasion), flow cytometry, Western blot, immunohistochemical analyses, and tumor xenograft. Results: The half-maximal inhibitory of curcumin for MG-63 cells at 24 hours was 27.6 µM. The number of colonies of MG-63 cells was decreased obviously upon curcumin (10 and 20 µM) treatment. We also found increased accumulation of MG-63 cells in the G2/M phase upon curcumin (10 and 20 µM) treatment. Apoptosis was increased in 10 and 20 µM curcumin-treated MG-63 cells. After incubation of physically wounded cells for 24 hours, the percentage wound width increased upon curcumin exposure. Curcumin obviously decreased the expression of pJAK-2 and pSTAT-3 in MG-63 cells in a dose-dependent manner. Curcumin dose-dependently inhibited the proliferation, migration, and invasion of MG-63 cells and induced arrest of the G0/G1 phase and apoptosis by inhibiting the p-JAK2/p-STAT3 pathway. The linear correlativity between expression of p-JAK2 and STAT3 was very prominent, and both were closely associated with lung metastasis. In vivo study suggested that curcumin suppressed tumor growth through JAK2/STAT3 signaling. Conclusion: Curcumin-mediated inhibition of the proliferation and migration of MG-63 cells was associated with inactivation of JAK/STAT signaling. [ABSTRACT FROM AUTHOR]