Osteosarcoma Patients Research Articles

Predictive value of serum alkaline phosphatase, tumor-specific growth factor, and macrophage migration inhibitory factor for the efficacy of immunotargeted therapy in osteosarcoma patients.

To assess the predictive value of serum alkaline phosphatase (ALP), tumor-specific growth factor (TSGF), and macrophage migration inhibitory factor (MIF) for the efficacy of combined immunosuppressive and targeted therapy in osteosarcoma (OS). We retrospectively analyzed clinical data from 161 OS patients treated at Xi'an Honghui Hospital from October 2020 to October 2022. Patients received 12 weeks of therapy with interferon-α (IFN-α) and bevacizumab. Serum levels of ALP, TSGF, and MIF were measured before and after treatment. Based on treatment efficacy, patients were categorized into effective and ineffective groups. Both univariate and logistic regression analyses were utilized to evaluate the influence of these biomarkers on therapy outcomes. A significant reduction in serum ALP, TSGF, and MIF levels post-treatment was found (all P<0.001). Higher pre-treatment levels of these biomarkers were associated with less effective outcomes (P<0.001). Pre-treatment levels of ALP, TSGF, and MIF are significant independent predictors of response to immunotargeted therapy in OS patients, suggesting their potential role in guiding treatment strategies.

Age-dependent molecular variations in osteosarcoma: implications for precision oncology across pediatric, adolescent, and adult patients.

Osteosarcoma is a leading subtype of bone tumor affecting adolescents and adults. Comparative molecular characterization among different age groups, especially in pediatric, adolescents and adults, is scarce. We collected samples from 194 osteosarcoma patients, encompassing pediatric, adolescent, and adult cohorts. Genomic analyses were conducted to reveal prevalent mutations and compare molecular features in pediatric, adolescent, and adult patients. Samples from 194 osteosarcoma patients across pediatric to adult ages were analyzed, revealing key mutations such as TP53, FLCN, NCOR1, and others. Children and adolescents showed more gene amplifications and HRD mutations, while adults had a greater Tumor Mutational Burden (TMB). Mutations in those over 15 were mainly in cell cycle and PI3K/mTOR pathways, while under 15s had more in cell cycle and angiogenesis with higher VEGFA, CCND3, TFEB mutations. CNV patterns varied with age: VEGFA and XPO5 amplifications more in under 25s, and CDKN2A/B deletions in over 25s. Genetic alterations in genes like MCL1 and MYC were associated with poor prognosis, with VEGFA mutations also indicating worse outcomes. 58% of patients had actionable mutations, suggesting opportunities for targeted therapies. Age-specific patterns were observed, with Multi-TKI mutations more common in younger patients and CDK4/6 inhibitor mutations in adults, highlighting the need for personalized treatment approaches in osteosarcoma. In a small group of patients with VEGFR amplification, postoperative treatment with multi-kinase inhibitors resulted in a PR in 3 of 13 cases, especially in patients under 15. A significant case involved a 13-year-old with a notable tumor size reduction achieving PR, even with other genetic alterations present in some patients with PD. This study delineates the molecular differences among pediatric, adolescent, and adult osteosarcoma patients at the genomic level, emphasizing the necessity for precision diagnostics and treatment strategies, and may offer novel prognostic biomarkers for patients with osteosarcoma. These findings provide a significant scientific foundation for the development of individualized treatment approaches tailored to patients of different age groups.

Circular RNA IARS modulates the progression and ferroptosis of osteosarcoma via sponging miR-188-5p from RAB14.

Osteosarcoma (OS) is a common primary bone tumor in children and adolescents. Circular RNA (circRNA)-IARS acts as an oncogene in multiple human tumors. However, the circ-IARS function in OS is unclear. This research aimed to elucidate the roles and mechanisms of circ-IARS in OS. In this study, circ-IARS expressions were raised in OS tissues and cells. circ-IARS expressions were closely related to clinical stage and distant metastasis. Furthermore, overall survival rates were reduced in OS patients with high circ-IARS levels. Also, silencing circ-IARS weakened OS cell proliferation and invasion, yet enhanced cell ferroptosis. Mechanistically, circ-IARS targeted miR-188-5p to regulate RAB14 expressions in OS cells. Moreover, circ-IARS knockdown repressed OS cell proliferation, invasion, and induced ferroptosis, yet these impacts were abolished by co-transfection with anti-miR-188-5p or pcDNA-RAB14. Meanwhile, interference with circ-IARS reduced OS cell proliferation, and decreased RAB14 (a member of the RAS oncogene family), GPX4, and xCT (crucial ferroptosis regulators) expressions in vivo. In conclusion, circ-IARS facilitated OS progression via miR-188-5p/RAB14.

USP5 promotes tumorigenesis by activating Hedgehog/Gli1 signaling pathway in osteosarcoma.

Changes in protein ubiquitination have been linked to cancer. Deubiquitinating enzymes (DUBs) counteract E3 ligase activities and have emerged as promising targets for cancer treatment. Ubiquitin-specific peptidase 5 (USP5) is a member of the DUBs family and has been implicated in promoting tumorigenesis in numerous cancers. However, the clinical significance and biological function of USP5 in osteosarcoma (OS) remains unclear. Here, we found elevated USP5 expression in OS tissues compared with normal bone tissues. Furthermore, we observed significant associations of elevated USP5 levels with increased mortality and more malignant phenotypes in OS patients. Moreover, our results revealed that USP5 could facilitate metastasis and cell progression in OS by activating the hedgehog (Hh) signaling pathway using cultured cells and animal tumor models. Mechanistically, USP5 appeared to stabilize and deubiquitinate Gli1, a key mediator of the Hh signaling pathway. Additionally, the oncogenic effect of USP5 in OS was dependent on Gli1 stability. Our findings support the model where USP5 contributes to OS pathogenesis by activating the Hh/Gli1 signaling pathway, making USP5 a potential diagnostic and therapeutic target for OS.

A Specific, Measurable, Achievable, Relevant, Timed (SMART) Nursing Project Reduces Anxiety, Depression, and Post-Traumatic Stress Disorder in Parents of Childhood or Adolescent Osteosarcoma Patients.

Specific, measurable, achievable, relevant, timed (SMART) principle improves the nursing utility by setting individual goals for participants and helping them to achieve these goals. Our study intended to investigate the impact of a SMART nursing project on reducing mental stress and post-traumatic stress disorder (PTSD) in parents of childhood or adolescent osteosarcoma patients. In this randomized, controlled study, 66 childhood or adolescent osteosarcoma patients and 126 corresponding parents were enrolled and divided into SMART or normal care (NC) groups at a 1:1 ratio. All parents received a 3-month corresponding intervention and a 6-month interview. Our study revealed that the self-rating anxiety scale score at the 3rd month (M3) (P < 0.05) and the 6th month (M6) (P < 0.01), and anxiety rate at M3 (P < 0.05) and M6 (P < 0.05) were lower in parents in SMART group vs. NC group. The self-rating depression scale score at M3 and M6, and depression rate at M3 and M6 were lower in parents in SMART group vs. NC group (all P < 0.05). Impact of events scale-revised score at the 1st month (M1) (P < 0.05), M3 (P < 0.05), and M6 (P < 0.01) were lower in parents in SMART group vs. NC group. By subgroup analyses, the SMART nursing project showed better impacts on decreasing anxiety, depression, and PTSD in parents with an undergraduate education or above than in those with a high school education or less. Conclusively, SMART nursing project reduces anxiety, depression, and PTSD in parents of childhood or adolescent osteosarcoma patients, which is more effective in those with higher education.

Sox9: A potential regulator of cancer stem cells in osteosarcoma.

Osteosarcoma is a highly aggressive bone tumor primarily affecting children and adolescents. Despite advancements in treatment modalities, the prognosis for osteosarcoma patients remains poor, emphasizing the need for a deeper understanding of its underlying mechanisms. In recent years, the concept of cancer stem cells (CSCs) has emerged as a crucial factor in tumor initiation, progression, and therapy resistance. These specialized subpopulations of cells possess self-renewal capacity, tumorigenic potential, and contribute to tumor heterogeneity. Sox9, a transcription factor known for its critical role in embryonic development and tissue homeostasis, has been implicated in various malignancies, including osteosarcoma. This review aims to summarize the current knowledge regarding the role of Sox9 in CSCs in osteosarcoma and its potential implications as a prognosis and therapeutic target.

Diagnostic value of combined detection of AKP, TSGF, and LDH for pediatric osteosarcoma: a case-control study.

To evaluate the diagnostic value of serum alkaline phosphatase (AKP), tumor-supplied growth factor group (TSGF), and lactate dehydrogenase (LDH) for pediatric osteosarcoma. A retrospective analysis of clinical data from 81 pediatric osteosarcoma patients (osteosarcoma group) and 63 patients with benign bone tumors (benign bone tumor group) admitted to Yantaishan Hospital from February 2023 to November 2023 was conducted. Basic and clinical data differences between the two groups of children were compared. A multivariate regression model was established to determine predictive factors for pediatric osteosarcoma, and the diagnostic value of identified indicators for pediatric osteosarcoma was evaluated. Osteosarcoma group demonstrated significantly higher serum AKP (375.76±73.47 vs 286.12±76.50 U/L), TSGF (69.01±16.30 vs 53.57±16.37 U/mL), and LDH (269.55±66.96 vs 207.46±59.20 U/L) levels as compared to the benign bone tumor group. Correlation analysis suggested significant positive correlations between AKP (rho=0.505), TSGF (rho=406), LDH (rho=0.449) and pediatric osteosarcoma. Multivariate regression analysis showed serum AKP, TSGF, and LDH were independent predictive factor for pediatric osteosarcoma. The AUC value for AKP was 0.794, with a Youden index of 0.459; the AUC value for TSGF was 0.736, with a Youden index of 0.406; and the AUC value for LDH was 0.761, with a Youden index of 0.462. The combined use of these three biomarkers yielded an AUC of 0.886. The combined detection of serum AKP, TSGF, and LDH can enhance the diagnostic accuracy of pediatric osteosarcoma, providing important evidence for clinical treatment.

Clinical and therapeutical significances of the cluster and signature based on oxidative stress for osteosarcoma.

It is of great clinical significance to find out the ideal tumor biomarkers and therapeutic targets to improve the prognosis of patients with osteosarcoma (OS). Oxidative stress (OXS) can directly target intracellular macromolecules and exhibit dual effects of tumor promotion and suppression. OXS-related genes (OXRGs) were extracted from public databases, including TARGET and GEO. Univariate Cox regression analysis, Random Survival Forest algorithm, and LASSO regression were performed to identify prognostic genes and establish the OXS-signature. The efficacy of the OXS-signature was further evaluated by Kaplan-Meier curves and timeROC package. Evaluation of immunological characteristics was achieved based on ESTIMATE algorithm and ssGSEA. Submap algorithm was used to explore the response to anti-PD1 and anti-CTLA4 therapy for OS. Drug response prediction was conducted by using pRRophetic package. The expression values of related genes in the OXS-signature were detected with PCR assays. Two OXS-clusters were identified for OS, with remarkable differences of clusters presented in prognosis. Kyoto Encyclopedia of Genes Genomes (KEGG) analysis showed that differentially expressed genes (DEGs) between the OXS-clusters were significantly enriched in several immune-related pathways. Patients with lower OS-scores attained better clinical outcomes, and presented more sensitivity to ICB therapy. By contrast, OS patients with higher OS-scores revealed more sensitivity to certain drugs. Furthermore, critical genes, RHBDL2 and CGREF1 from the model, were significantly higher expressed in OS cell lines. Our study identified the clusters and signature based on OXS, which would lay the foundation for molecular experimental research, disease prevention and treatment of OS.

PROGNOSTIC IMPLICATIONS OF PD-L1 EXPRESSION AND LOSS OF PTEN IN PATIENTS WITH RHABDOMYOSARCOMA, EWING'S SARCOMA AND OSTEOSARCOMA.

In children, osteosarcoma (OS), Ewing's sarcoma (ES), and rhabdomyosarcoma (RMS) are the most common sarcomas. A link between the anti-programmed death ligand-1 PD-L1 and the tumor suppressor phosphatase and tensin homologue (PTEN) expression has been described in many tumors. The aim of this work is to determine clinicopathological relationships and the possible prognostic significance of PD-L1 and PTEN expression in rhabdomyosarcoma (RMS), Ewing's sarcoma (ES), and osteosarcoma (OS). Expression of PD-L1 and PTEN were examined by immunohistochemistry in 45 archival RMS, ES, and OS cases. The positive expression of PD-L1 was found in 16.7% and 31.6% of ES and OS, respectively. The negative PD-L1 was related to a substantially longer survival in ES cases (p = 0.045), but positive PD-L1 expression was significantly associated with the increased tumor stage and vascular invasion in the OS cases (p = 0.005 and p = 0.002), respectively. On the other hand, PTEN loss was strongly associated with deep tumor, high tumor grade, and recurrence in RMS (p = 0.002, p = 0.045, and p = 0.026, respectively). However, PTEN loss was significantly absent in ES as tumor grade increased (p = 0.031). It is noteworthy that tumor recurrence, the loss of PTEN, and positive PD-L1 were all considered predictive factors in OS patients (p = 0.045, p = 0.032, and p = 0.02, respectively). In children, OS and ES have positive PD-L1 expression, which has an independent unfavorable prognostic effect and raises the possibility of using PD-L1 as a therapeutic target. OS, ES, and RMS prognosis are all predicted by PTEN loss.

FRS2 regulated by miR-429 and miR-206 promotes angiogenesis in osteosarcoma

FRS2 has demonstrated oncogenic roles in various malignancies, including liposarcoma and giant cell tumor of bone. However, its role in osteosarcoma remains less understood, and the upstream regulatory molecules influencing FRS2 remain unclear. This study aims to explore the clinical implications and biological function of FRS2 in osteosarcoma, and the potential regulatory microRNAs (miRNAs) governing its expression. Our study indicated significant upregulation of FRS2 in osteosarcoma cells and tissues by Western blotting and immunohistochemical staining. Elevated FRS2 expression correlated positively with increased angiogenesis and poor prognosis, possibly serving as an independent prognostic indicator for osteosarcoma patients. Functional assays revealed that attenuating FRS2 in osteosarcoma cells could mitigate proliferation, migration, and angiogenesis of vascular endothelial cells. Further investigations revealed that miR-429 and miR-206 directly targeted FRS2, exerting a negative regulation on its expression. Furthermore, FRS2 played a role in repressing osteosarcoma advancement influenced by miR-429 or miR-206. In summary, FRS2, influenced by miR-429 and miR-206, emerges as a promising therapeutic candidate for antiangiogenic osteosarcoma treatments.

Solute carrier family 35 member A2 regulates mitophagy through the PI3K/AKT/mTOR axis, promoting the proliferation, migration, and invasion of osteosarcoma cells

The treatment of osteosarcoma patients exhibits individual variability, underscoring the critical importance of targeted therapy. Although (Solute carrier family 35 member A2) SLC35A2′s role in the progression of various cancers has been extensively investigated, its specific implications in osteosarcoma remain unexplored. Leveraging data from the (The Cancer Genome Atlas) TCGA and (Genotype-Tissue Expression) GTEx databases, we have discerned that SLC35A2 is notably upregulated in osteosarcoma and correlates with the prognosis of osteosarcoma patients. Consequently, it becomes imperative to delve into the role of SLC35A2 in the context of osteosarcoma. Our research substantiates that SLC35A2 exerts a notable influence on mitochondrial autophagy in osteosarcoma, thereby exerting cascading effects on the proliferation, migration, invasion, and apoptosis of osteosarcoma cells. Mechanistically, SLC35A2 orchestrates mitochondrial autophagy via the PI3K/AKT/mTOR signaling pathway. Moreover, we have conducted rigorous animal experiments to further corroborate the repercussions of SLC35A2 on osteosarcoma growth. In summation, our study elucidates that SLC35A2′s modulation of mitochondrial autophagy through the PI3K/AKT/mTOR signaling pathway constitutes a pivotal factor in the malignant progression of osteosarcoma, unveiling promising therapeutic targets for patients grappling with this condition.

Establishment and Characterization of Cell Lines from Canine Metastatic Osteosarcoma.

Despite the advancements in treatments for other cancers, the outcomes for osteosarcoma (OSA) patients have not improved in the past forty years, especially in metastatic patients. Moreover, the major cause of death in OSA patients is due to metastatic lesions. In the current study, we report on the establishment of three cell lines derived from metastatic canine OSA patients and their transcriptome as compared to normal canine osteoblasts. All the OSA cell lines displayed significant upregulation of genes in the epithelial mesenchymal transition (EMT) pathway, and upregulation of key cytokines such as CXCL8, CXCL10 and IL6. The two most upregulated genes are MX1 and ISG15. Interestingly, ISG15 has recently been identified as a potential therapeutic target for OSA. In addition, there is notable downregulation of cell cycle control genes, including CDKN2A, CDKN2B and THBS1. At the protein level, p16INK4A, coded by CDKN2A, was undetectable in all the canine OSA cell lines, while expression of the tumor suppressor PTEN was variable, with one cell line showing complete absence and others showing low levels of expression. In addition, the cells express a variety of actionable genes, including KIT, ERBB2, VEGF and immune checkpoint genes. These findings, similar to those reported in human OSA, point to some genes that can be used for prognosis, targeted therapies and novel drug development for both canine and human OSA patients.

Exploring the immune microenvironment of osteosarcoma through T cell exhaustion-associated gene expression: a study on prognosis prediction.

Osteosarcoma is a highly aggressive type of bone cancer with a poor prognosis. In the tumor immune microenvironment, T-cell exhaustion can occur due to various factors, leading to reduced tumor-killing ability. The purpose of this study was to construct a prognostic model based on T-cell exhaustion-associated genes in osteosarcoma. Patient data for osteosarcoma were retrieved from the TARGET and GEO databases. Consensus clustering was employed to identify two novel molecular subgroups. The dissimilarities in the tumor immune microenvironment between these subgroups were evaluated using the "xCell" algorithm. GO and KEGG analyses were conducted to elucidate the underlying mechanisms of gene expression. Predictive risk models were constructed using the least absolute shrinkage and selection operator algorithm and Cox regression analysis. To validate the prognostic significance of the risk gene expression model at the protein level, immunohistochemistry assays were performed on osteosarcoma patient samples. Subsequently, functional analysis of the key risk gene was carried out through in vitro experimentation. Four gene expression signatures (PLEKHO2, GBP2, MPP1, and VSIG4) linked to osteosarcoma prognosis were identified within the TARGET-osteosarcoma cohort, categorizing patients into two subgroups. The resulting prognostic model showed strong predictive capability, with area under the receiver operating characteristic curve (AUC) values of 0.728/0.740, 0.781/0.658, and 0.788/0.642 for 1, 3, and 5-year survival in both training and validation datasets. Notably, patients in the low-risk group had significantly higher stromal, immune, and ESTIMATE scores compared to high-risk counterparts. Additionally, a nomogram was developed, exhibiting high accuracy in predicting the survival outcome of osteosarcoma patients. Immunohistochemistry, Kaplan-Meier, and time-dependent AUC analyses consistently supported the prognostic value of the risk model within our osteosarcoma patient cohort. In vitro experiments provided additional validation by demonstrating that the downregulation of GBP2 promoted the proliferation, migration, and invasion of osteosarcoma cells while inhibiting apoptosis. The current study established a prognostic signature associated with TEX-related genes and elucidated the impact of the pivotal gene GBP2 on osteosarcoma cells via in vitro experiments. Consequently, it introduces a fresh outlook for clinical prognosis prediction and sets the groundwork for targeted therapy investigations in osteosarcoma.

Necrotizing apoptosis-related genes prognosis and treatment effect analysis of osteosarcoma in children.

Immune cell homeostasis plays a crucial role in cancer research and therapeutic response. While chemotherapy and immunotherapy hold promise in treating osteosarcoma (OS), identifying patients who are likely to respond would significantly improve clinical practices. Necroptosis, a fundamental mechanism mediating chemotherapy and immunotherapy efficacy, offers valuable insights. In this context, subtypes based on necroptosis-related genes have been established to predict the response of OS patients to immunotherapy and chemotherapy. We conducted a high-throughput screening test to identify necroptosis-associated genes that regulate the development of osteosarcoma. Subsequently, the ConsensusClusterPlus package was employed to classify OS patients into subtypes, enabling comparisons of prognosis and clinical information between these subtypes. Patients from the TARGET-OS and GSE21257 datasets were stratified into high-risk and low-risk groups, and their prognoses were compared. Additionally, we assessed the accuracy of the Risk Scoring Model in predicting prognosis, identified independent prognostic factors and explored potential chemotherapeutic agents and immunotherapy drugs. Through the intersection of expression profiles from the TARGET-OS and GSE21257 datasets, we have identified a total of 92 genes associated with necroptosis. Based on differences in the expression of these genes, patients were divided into three subtypes, and we investigated the differences in tumor-infiltrating immune cells, immune-related pathways, and prognosis among these subtypes. Our nomogram effectively differentiated subtypes with distinct responses to chemotherapy and immunotherapy. The established signature demonstrated superior prediction ability compared with single clinical indicators. This pioneering study unveils the prognostic role of necroptosis-related genes in OS patients, providing a promising alternative for prognostic prediction in clinical disease management. Moreover, our findings highlight the significance of immune cell homeostasis in cancer research and therapeutic response, underscoring its relevance in advancing current treatment strategies.

Essential genes analysis reveals small ribosomal subunit protein eS28 may be a prognostic factor and potential vulnerability in osteosarcoma

BackgroundOsteosarcoma, the most common primary malignant bone tumor, is currently treated with surgery combined with chemotherapy, but the limited availability of targeted drugs contributes to a poor prognosis. Identifying effective therapeutic targets is crucial for improving the prognosis of osteosarcoma patients. MethodsWe screened the DepMap database to identify essential genes as potential therapeutic targets for osteosarcoma. Gene Set Enrichment Analysis (GSEA) was employed to elucidate the biological roles of these essential genes. Promising candidates were filtered through univariate and multivariate Cox analyses, as well as Kaplan-Meier survival analyses using the GSE21257-OSA and TARGET-OSA datasets. The functional role of the target gene was assessed through cell experiments. Additionally, an in situ nude mice model was established to observe the gene's function, and RNA sequencing was utilized to explore the underlying molecular mechanism. ResultsA total of 934 essential genes were identified based on their effects (Chronos) using the DepMap database. These genes were primarily enriched in the ribosome pathway according to GSEA analysis. Among them, 195 genes were associated with the ribosome pathway. Rps28, Rps7, and Rps25 were validated as promising candidates following univariate and multivariate Cox analyses of the TARGET-OSA and GSE21257-OSA datasets. Kaplan-Meier survival analyses indicated Rps28 represented an especially promising target, with high expression correlating with poor prognosis. Knockdown of small ribosomal subunit protein eS28, the protein of Rps28, inhibited proliferation, migration, and invasion in both in vitro and in vivo experiments. Silencing RPS28 affected the MAPK signaling pathway in osteosarcoma. ConclusionIn summary, Rps28 has been identified as an essential gene for osteosarcoma cell survival and eS28 may serve as a potential vulnerability in osteosarcoma.

Various Treatment Options in Osteosarcoma

The surgical treatment of osteosarcoma has historically been amputation/disarticulation. While there has been improvement in survival from inclusion of chemotherapy on the one hand, it has been paralleled by a shift of surgical treatment from amputation toward limb salvage surgery. Limb salvage should be considered in a patient only if the surgeon is reasonably confident that surgical excision of the tumor with wide margins is feasible, and that the expected function of the limb after limb salvage surgery will be better than ablative surgery in the form of amputation/disarticulation. Aim of this study is study the various treatment options in patients of osteosarcoma. Keywords: OS- osteosarcoma, CT-chemotherapy, RT-radiotherapy

Construction and validation of a novel NAD+ metabolism-related risk model for prognostic prediction in osteosarcoma.

Currently, the prognosis of osteosarcoma (OS) remains discouraging, especially in elderly/metastatic OS patients. By impairing the antitumor effect of immune cells, tumor immune microenvironment (TIME) provides an environment conducive to tumor proliferation, which highly requires accelerated nicotinamide adenine dinucleotide (NAD+) metabolism for energy. Recently, many genes involved in the sustained production of NAD+ in malignant tumors have been verified to be possible prognostic indicators and therapeutic targets. Therefore, the current study was to probe into the association of NAD+ metabolism-related genes with TIME, immunotherapeutic response, and prognosis in OS. All OS data for the study were acquired from TARGET and GEO databases. In bioinformatics analysis, we performed Cox analysis, consensus clustering, principal component analysis, t-distributed stochastic neighbor embedding, uniform manifold approximation and projection, gene set enrichment analysis, gene set variation analysis, Lasso analysis, survival and ROC curves, nomogram, immune-related analysis, drug sensitivity analysis, and single-cell RNA sequencing (scRNA-seq) analysis. Cell transfection assay, RT-qPCR, western blot analysis, as well as cell wound healing, migration, and invasion assays were performed in vitro. Bioinformatics analysis identified A&B clusters and six NAD+ metabolism-related differentially expressed genes, constructed risk model and nomogram, and performed immune-related analysis, drug susceptibility analysis, and scRNA-seq analysis to inform the clinical treatment framework. In vitro experiment revealed that CBS and INPP1 can promote migration, proliferation as well as invasion of OS cells through TGF-β1/Smad2/3 pathway. Based on bioinformatics analysis and in vitro validation, this study confirmed that NAD+ metabolism affects TIME to suggest the prognosis of OS.

Single-cell RNA sequencing reveals the immune microenvironment landscape of osteosarcoma before and after chemotherapy

Chemotherapy, a primary treatment for osteosarcoma (OS), has limited knowledge regarding its impact on tumor immune microenvironment (TIME). Here, tissues from 6 chemotherapy-naive OS patients underwent single-cell RNA sequencing (scRNA-seq) and were analyzed alongside public dataset (GSE152048) containing 7 post-chemotherapy OS tissues. CD45+ (PTPRC+) cells were used for cell clustering and annotation. Changes in immune cell composition pre- and post-chemotherapy were characterized. Totally, 28,636 high-quality CD45+ (PTPRC+) cells were extracted. Following chemotherapy, the proportions of regulatory T cells (Tregs) and activated CD8 T cells decreased, while CD8 effector T cells increased. GO analysis indicated that differentially expressed genes (DEGs) in T cells were associated with cell activation, adaptive immune response, and immune response to tumor cells. Furthermore, the proportions of plasma cells increased, while naive B cells decreased. B cell surface receptors expression was upregulated, and GO analysis revealed DEGs of B cells were mainly enriched in B cell-mediated immunity and B cell activation. Moreover, M2 polarization of macrophages was suppressed post-chemotherapy. Overall, this study elucidates chemotherapy remodels the OS TIME landscape, triggering immune heterogeneity and enhancing anti-tumor properties.

Lipid metabolism-derived FAAH is a sensitive marker for the prognosis and immunotherapy of osteosarcoma patients

Lipid metabolism in cancer refers to the alterations in how cancer cells process and utilize lipids, a type of fat molecule. It was investigated how lipid metabolism relates to osteosarcoma. Genes relevant to lipid metabolism were gathered to create lipid metabolism-associated clusters and locate the dangerous marker. We investigated FAAH's prognostic significance, route annotation, immunotherapy response, and medication prediction. Besides, FAAH is proven to be a potent, dangerous marker that may promote growth and migration and inhibit the apoptosis of osteosarcoma. FAAH exhibits higher expression levels in tumor tissues as compared to normal tissues. In conclusion, FAAH is identified in this work as a potentially dangerous gene and immunotherapy determinant. This study requires more investigation to determine how FAAH influences the immune response in osteosarcoma.

Identification and experimental validation of Stearoyl-CoA desaturase is a new drug therapeutic target for osteosarcoma

Osteosarcoma (OS) is the most common malignant bone tumor. Fatty acid reprogramming plays an essential role in OS progression. However, new fatty acid related therapeutic targets of OS have not been completely elucidated. Therefore, we firstly identified 113 differentially expressed fatty acid metabolism genes using bioinformatic analysis, 19 of which were found to be associated with OS prognosis. Then, 7 hub genes were screened out and yielded a strong prediction accuracy (AUC value = 0.88, at 3 years) for predicting the survival status of OS patients. Furthermore, we confirmed that SCD was highly expressed in OS cells and patients. And Knock-down of SCD impaired proliferation and migration of OS cells. Moreover, SCD was transcriptionally activated by c-Myc to promote proliferation and migration of OS cells. Finally, SCD inhibitor could significantly induce OS ferroptosis in vitro and in vivo. In conclusion, we identified that SCD was a reliable risk factor for OS patients. And SCD was activated by c-Myc. The inhibitor of SCD could significantly impaired OS growth and induce OS ferroptosis, which indicated that SCD was a potential drug target for OS treatment.