Comparison of oncological and functional outcomes in Lower-limb osteosarcoma pediatric patient : A large single-center retrospective cohort study.

OBJECTIVE: Treating pediatric osteosarcoma in long bones is challenging due to skeletal immaturity, which restricts the generalizability of insights derived from adult patients. Are there disparities in outcomes? How should surgical protocols be tailored for children of varying ages? What are the specific postoperative complications? A large single-center retrospective cohort study of 345 patients under 14 years old with lower-limb osteosarcoma treated in our department since 2000 was conducted to address these inquiries. METHODS: A retrospective analysis of 345 pediatric patients with lower-limb osteosarcoma admitted to our department between 2000 and 2019 was conducted. Clinical and functional outcomes were compared based on age groups, surgical methods, type of prosthesis, and primary tumor location. Patients were divided into the Low-age group (≤10 y old) and the High-age group (>10 y old). Overall Survival rate (OS), Progression-Free Survival rate (PFS), and prosthesis survival rate were assessed using Kaplan-Meier curves, Non-parametric survival analysis (log-rank test) and Univariate cox regression were used for comparison. The incidence of complications, local relapse rate (LRR), metastasis rate, final limb-salvage and amputation rate, and Musculoskeletal Tumor Society (MSTS) score of different independent groups were further evaluated using χ2 test or Fisher's exact test, and t-test was employed to evaluate the measurement data. RESULTS: The average age of the patients was 11.10±2.32 years (ranging from 4 to 14 y), with an average follow-up duration of 48.17 months. The 5, 10, and 15-year OS rates were 50.3%, 43.8%, and 37.9%, respectively. The Progression-Free survival rate was 44.8% at 5 years and 41.1% at 10 years. The final limb salvage rate was 61.45%, while the final amputation rate was 38.55%. The low-age group had a higher amputation rate compared to the high-age group (48.00% vs. 33.18%, P =0.009). The overall LRR was 9.28%, and the incidence of metastasis was 28.99%. The LRR of the limb-salvage group was higher than the amputation group ( P =0.004). The low-age group experienced more prosthesis-related complications than the high-age group ( P =0.001). The most common prosthesis-related complication in the low-age group was soft-tissue failure, while the periprosthetic infection was most frequent in the high-age group. The high-age group had a higher cumulative prosthesis survival compared to the low-age group ( P =0.0097). Modular prosthesis showed better MSTS scores and higher cumulative prosthetic survival than expandable prosthesis in pediatric patients ( P <0.05). CONCLUSION: Limb preservation in pediatric patients becomes increasingly efficacious with advancing age, while consideration of amputation is warranted for younger patients. The prevailing postoperative complications associated with prosthesis encompass soft tissue failure and periprosthetic infection. Younger patients diagnosed with lower limb osteosarcoma exhibit a heightened amputation rate and a greater incidence of prosthesis-related complications.

Prognostic and predictive value of super-enhancer-derived signatures for survival and lung metastasis in osteosarcoma.

BACKGROUND: Risk stratification and personalized care are crucial in managing osteosarcoma due to its complexity and heterogeneity. However, current prognostic prediction using clinical variables has limited accuracy. Thus, this study aimed to explore potential molecular biomarkers to improve prognostic assessment. METHODS: High-throughput inhibitor screening of 150 compounds with broad targeting properties was performed and indicated a direction towards super-enhancers (SEs). Bulk RNA-seq, scRNA-seq, and immunohistochemistry (IHC) were used to investigate SE-associated gene expression profiles in osteosarcoma cells and patient tissue specimens. Data of 212 osteosarcoma patients who received standard treatment were collected and randomized into training and validation groups for retrospective analysis. Prognostic signatures and nomograms for overall survival (OS) and lung metastasis-free survival (LMFS) were developed using Cox regression analyses. The discriminatory power, calibration, and clinical value of nomograms were evaluated. RESULTS: High-throughput inhibitor screening showed that SEs significantly contribute to the oncogenic transcriptional output in osteosarcoma. Based on this finding, focus was given to 10 SE-associated genes with distinct characteristics and potential oncogenic function. With multi-omics approaches, the hyperexpression of these genes was observed in tumor cell subclusters of patient specimens, which were consistently correlated with poor outcomes and rapid metastasis, and the majority of these identified SE-associated genes were confirmed as independent risk factors for poor outcomes. Two molecular signatures were then developed to predict survival and occurrence of lung metastasis: the SE-derived OS-signature (comprising LACTB, CEP55, SRSF3, TCF7L2, and FOXP1) and the SE-derived LMFS-signature (comprising SRSF3, TCF7L2, FOXP1, and APOLD1). Both signatures significantly improved prognostic accuracy beyond conventional clinical factors. CONCLUSIONS: Oncogenic transcription driven by SEs exhibit strong associations with osteosarcoma outcomes. The SE-derived signatures developed in this study hold promise as prognostic biomarkers for predicting OS and LMFS in patients undergoing standard treatments. Integrative prognostic models that combine conventional clinical factors with these SE-derived signatures demonstrate substantially improved accuracy, and have the potential to facilitate patient counseling and individualized management.

A Disulfidptosis-Related Gene Signature Associated with Prognosis and Immune Cell Infiltration in Osteosarcoma.

Osteosarcoma (OS) stands as a leading aggressive bone malignancy that primarily affects children and adolescents worldwide. A recently identified form of programmed cell death, termed Disulfidptosis, may have implications for cancer progression. Yet, its role in OS remains elusive. To elucidate this, we undertook a thorough examination of Disulfidptosis-related genes (DRGs) within OS. This involved parsing expression data, clinical attributes, and survival metrics from the TARGET and GEO databases. Our analysis unveiled a pronounced association between the expression of specific DRGs, particularly MYH9 and LRPPRC, and OS outcome. Subsequent to this, we crafted a risk model and a nomogram, both honed for precise prognostication of OS prognosis. Intriguingly, risks associated with DRGs strongly resonated with immune cell infiltration levels, myriad immune checkpoints, genes tethered to immunotherapy, and sensitivities to systematic treatments. To conclude, our study posits that DRGs, especially MYH9 and LRPPRC, hold potential as pivotal architects of the tumor immune milieu in OS. Moreover, they may offer predictive insights into treatment responses and serve as reliable prognostic markers for those diagnosed with OS.

Preoperative denosumab treatment in patients with giant cell bone tumors in limbs: A retrospective study using propensity score matching.

BACKGROUND AND OBJECTIVES: Denosumab is recommended for advanced giant cell tumor of bone (GCTB) that is unresectable or resectable with unacceptable morbidity. But the effect of preoperative denosumab treatment on the local control GCTB remains controversial. METHODS: We conducted a study of 49 patients with GCTB in the limbs treated with denosumab before surgery and 125 patients without in our hospital from 2010 to 2017. Propensity-score matching (PSM) at a 1:1 ratio between the denosumab and control groups was performed to minimize possible selection bias, and compared the recurrence rate, limb function, and surgical degradation between the two groups. RESULTS: The 3-year recurrence rates in the denosumab group and the control group were 20.4% and 22.9% after PSM, respectively (p = 0.702). In the denosumab group, 75.5% (n = 37/49) of patients experienced surgical downgrading. Limb joint preservation rates were 92.1% (35) for 38 patients treated with denosumab and 60.2% (71) for 118 control subjects. (p ≺ 0.001). Postoperative MSTS were higher in patients in the denosumab group than in the control group (24.1 vs. 22.6, p = 0.034). CONCLUSIONS: Preoperative denosumab treatment did not result in an increased risk of local recurrence of GCTB. Patients with advanced GCTB may benefit from preoperative denosumab treatment for surgical downgrading and the preservation of the joint.

Lactate regulates cell cycle by remodelling the anaphase promoting complex.

Lactate is abundant in rapidly dividing cells owing to the requirement for elevated glucose catabolism to support proliferation1-6. However, it is not known whether accumulated lactate affects the proliferative state. Here we use a systematic approach to determine lactate-dependent regulation of proteins across the human proteome. From these data, we identify a mechanism of cell cycle regulation whereby accumulated lactate remodels the anaphase promoting complex (APC/C). Remodelling of APC/C in this way is caused by direct inhibition of the SUMO protease SENP1 by lactate. We find that accumulated lactate binds and inhibits SENP1 by forming a complex with zinc in the SENP1 active site. SENP1 inhibition by lactate stabilizes SUMOylation of two residues on APC4, which drives UBE2C binding to APC/C. This direct regulation of APC/C by lactate stimulates timed degradation of cell cycle proteins, and efficient mitotic exit in proliferative human cells. This mechanism is initiated upon mitotic entry when lactate abundance reaches its apex. In this way, accumulation of lactate communicates the consequences of a nutrient-replete growth phase to stimulate timed opening of APC/C, cell division and proliferation. Conversely, persistent accumulation of lactate drives aberrant APC/C remodelling and can overcome anti-mitotic pharmacology via mitotic slippage. In sum, we define a biochemical mechanism through which lactate directly regulates protein function to control the cell cycle and proliferation.

Autologous menisci-cruciate ligament composite as a flap for soft tissue reconstruction following malignant bone tumor resection around the knee.

BACKGROUND: Despite significant improvements in oncological treatment, the management of soft tissue defects following malignant tumor resection remains challenging. We investigated whether autologous menisci and cruciate ligament, which are traditionally discarded, can be recycled as a supplemental flap in repairing soft tissue defects following malignant bone tumor resection and endoprosthetic reconstruction around the knee. METHODS: Four knee specimens were dissected to provide a basis for the design of the menisci-cruciate ligament composite. Then, 40 patients with bone malignancies around the knee were enrolled and underwent reconstruction with free or vascularized composite following malignant tumor resection. The clinical, radiographic, and functional outcomes of this technique were evaluated in >1-year follow-up in each patient and compared with 87 patients who suffered from bone malignancies around the knee and were treated by limb salvage but without composite at our center over the same period. During the follow-up, a composite from one patient who underwent secondary amputation was retrieved and examined for in vivo remodeling. RESULTS: Fourteen patients were treated with vascularized composite transfer (10 distal femurs and 4 proximal tibias) and 26 patients with free composite transfer (19 distal femurs and 7 proximal tibias). The composite can be used to cover the area of soft tissue defect from 22 to 48.38 cm2 (34.67 ± 6.48 cm2 ). With contrast-enhanced ultrasound, peripheral rim healing and dotted blood flow signal at the side of anastomosis were detected on a patient 16 months after free composite transfer. Gross macroscopic remodeling and histopathologic analysis of a retrieved composite also indicated good healing with surrounding tissues and living cells in the composite. The complications and oncologic outcomes were comparable between study and control cohorts, but better Musculoskeletal Tumor Society (MSTS) score for patients reconstructed with composite (26.68 vs. 25.66, p  = 0.004). Of note, MSTS score was higher for patients reconstructed with composite at distal femur subdivision compared with the same subdivision in the control cohort (26.97 vs. 25.90, p  = 0.009). No statically significant difference was noted in complications, oncologic, and functional outcomes for patients reconstructed with free or vascularized composite. CONCLUSION: Autogenous menisci-cruciate ligament composite is an alternative option for soft tissue reconstruction. Either vascularized or free composite can be applied, depending on the size and localization of the defect.

Surgical Strategy and Application of Robotic-Assisted Benign Sacral Neurogenic Tumor Resection.

BACKGROUND: Robotic surgery may be advantageous in neurogenic sacral tumor resection but only a few studies reported robotic-assisted neurogenic sacral tumor resection. OBJECTIVE: To propose a new surgical strategy for robotic-assisted benign sacral neurogenic tumor resection and introduce the ultrasonic osteotomy surgical system in robotic surgery. METHODS: Twelve patients who had robotic-assisted primary benign sacral neurogenic tumor resection between May 2015 and March 2021 were included. Our surgical strategy divides tumors into 4 types. Type I: Presacral tumors with diameter <10 cm. Type II: Narrow-base tumors involving the sacrum with diameter <10 cm. Type III: Broad-base tumors involving the sacrum with diameter <10 cm. Type IV: Tumors involving sacral nerve roots ≥2 levels and/or with diameter ≥10 cm. RESULTS: Five type I, 5 type II, and 1 type III patients underwent tumor resection via an anterior approach, and 1 type IV patient via a combined approach. The median operation time, blood loss, and postoperative hospital stay of type I and II were much less than those of type IV. The ultrasonic osteotomy surgical system facilitated osteotomy in 2 type II and 1 type III patients. Eleven patients had total resections, and 1 type III patient had a partial resection. During the follow-up period of 7.9 to 70.9 months (median: 28.5 months), no local recurrences or deaths were noted. CONCLUSION: With the largest single-center series to our knowledge, this surgical strategy helped to guide robotic-assisted benign sacral neurogenic tumor resection. The ultrasonic osteotomy surgical system was effective for type II and III.

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

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

The hexosamine biosynthesis pathway-related gene signature correlates with immune infiltration and predicts prognosis of patients with osteosarcoma.

Objectives: Osteosarcoma is a malignant bone tumor with poor outcomes affecting the adolescents and elderly. In this study, we comprehensively assessed the metabolic characteristics of osteosarcoma patients and constructed a hexosamine biosynthesis pathway (HBP)-based risk score model to predict the prognosis and tumor immune infiltration in patients with osteosarcoma. Methods: Gene expression matrices of osteosarcoma were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO) databases. GSVA and univariate Cox regression analysis were performed to screen the metabolic features associated with prognoses. LASSO regression analysis was conducted to construct the metabolism-related risk model. Differentially expressed genes (DEGs) were identified and enrichment analysis was performed based on the risk model. CIBERSORT and ESTIMATE algorithms were executed to evaluate the characteristics of tumor immune infiltration. Comparative analyses for immune checkpoints were performed and the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm was used to predict immunotherapeutic response. Finally, hub genes with good prognostic value were comprehensive analyzed including drug sensitivity screening and immunohistochemistry (IHC) experiments. Results: Through GSVA and survival analysis, the HBP pathway was identified as the significant prognostic related metabolism feature. Five genes in the HBP pathway including GPI, PGM3, UAP1, OGT and MGEA5 were used to construct the HBP-related risk model. Subsequent DEGs and enrichment analyses showed a strong correlation with immunity. Further, CIBERSORT and ESTIMATE algorithms showed differential immune infiltration characteristics correlated with the HBP-related risk model. TIDE algorithms and immune checkpoint analyses suggested poor immunotherapeutic responses with low expression of immune checkpoints in the high-risk group. Further analysis revealed that the UAP1 gene can predict metastasis. IHC experiments suggested that UAP1 expression correlated significantly with the prognosis and metastasis of osteosarcoma patients. When screening for drug sensitivity, high UAP1 expression was suggestive of great sensitivity to antineoplastic drugs including cobimetinib and selumetinib. Conclusion: We constructed an HBP-related gene signature containing five key genes (GPI, PGM3, UAP1, OGT, MGEA5) which showed a remarkable prognostic value for predicting prognosis and can guide immunotherapy and targeted therapy for osteosarcoma.

METTL14-mediated epitranscriptome modification of MN1 mRNA promote tumorigenicity and all-trans-retinoic acid resistance in osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is the most common primary malignant bone tumor in adolescents. The molecular mechanism behind OS progression and metastasis remains poorly understood, which limits the effectiveness of current therapies. RNA N6-methyladenosine (m6A) modification plays a critical role in influencing RNA fate. However, the biological significance of m6A modification and its potential regulatory mechanisms in the development of OS remain unclear. METHODS: Liquid chromatography-tandem mass spectrometry (LC-MS/MS), dot blotting, and colorimetric ELISA were used to detect m6A levels. Western blotting, quantitative real-time PCR (RT-qPCR) and immunohistochemistry (IHC) were used to investigate METTL14 expression levels. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and transcriptomic RNA sequencing (RNA-seq) were used to screen the target genes of METTL14. RNA pull-down and RNA immunoprecipitation (RIP) assays were conducted to explore the specific binding of target genes and relevant m6A "readers". RNA stability and polysome analysis assays were used to detect the half-lives and translation efficiencies of the downstream genes of METTL14. IHC and clinical data were applied to explore the clinical correlations of METTL14 and its downstream target genes with the prognosis of OS. FINDINGS: We observed the abundance of m6A modifications in OS and revealed that METTL14 plays an oncogenic role in facilitating OS progression. MeRIP-seq and RNA-seq revealed that MN1 is a downstream gene of METTL14. MN1 contributes to tumor progression and all-trans-retinoic acid (ATRA) chemotherapy resistance in OS. Mechanistically, MN1 is methylated by METTL14, specifically in the coding sequence (CDS) regions, and this modification is recognized by the specific m6A reader insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) to prevent MN1 mRNA degradation and promote it translation efficiency. IHC showed that MN1 expression was positively correlated with METTL14 and IGF2BP2 expression in OS tissues. The METTL14-IGF2BP2-MN1 panel demonstrated more promising prognostic value for OS patients than any of these molecules individually. INTERPRETATION: Our study revealed that METTL14 contributes to OS progression and ATRA resistance as an m6A RNA methylase by regulating the stability and translation efficiency of MN1 and thus provides both an underlying biomarker panel for prognosis prediction in OS patients. FUNDING: This work was supported by the National Natural Science Foundation of China (Grants 81972510 and 81772864).

Landscape of somatic alterations in large-scale solid tumors from an Asian population.

Extending the benefits of tumor molecular profiling for all cancer patients requires a comprehensive analysis of tumor genomes across distinct patient populations worldwide. In this study, we perform deep next-generation DNA sequencing (NGS) from tumor tissues and matched blood specimens from over 10,000 patients in China by using a 450-gene comprehensive assay, developed and implemented under international clinical regulations. We perform a comprehensive comparison of somatically altered genes, the distribution of tumor mutational burden (TMB), gene fusion patterns, and the spectrum of various somatic alterations between Chinese and American patient populations. Here, we show 64% of cancers from Chinese patients in this study have clinically actionable genomic alterations, which may affect clinical decisions related to targeted therapy or immunotherapy. These findings describe the similarities and differences between tumors from Chinese and American patients, providing valuable information for personalized medicine.

A Comprehensive Understanding of the Genomic Bone Tumor Landscape: A Multicenter Prospective Study.

Complexity and heterogeneity increases the difficulty of diagnosis and treatment of bone tumors. We aimed to identify the mutational characterization and potential biomarkers of bone tumors. In this study, a total of 357 bone tumor patients were recruited and the next generation sequencing (NGS)-based YuanSu450 panel, that includes both DNA and RNA sequencing, was performed for genomic alteration identification. The most common mutated genes in bone tumors included TP53, NCOR1, VEGFA, RB1, CCND3, CDKN2A, GID4, CCNE1, TERT, and MAP2K4. The amplification of genes such as NCOR1, VEGFA, and CCND3 mainly occurred in osteosarcoma. Germline mutation analysis reveal a high frequency of HRD related mutations (46.4%, 13/28) in this cohort. With the assistance of RNA sequencing, 16.8% (19/113) gene fusions were independently detected in 20% (16/79) of patients. Nearly 34.2% of patients harbored actionable targeted mutations, of which the most common mutation is CDKN2A deletion. The different mutational characterizations between juvenile patients and adult patients indicated the potential effect of age in bone tumor treatment. According to the genomic alterations, the diagnosis of 26 (7.28%) bone tumors were corrected. The most easily misdiagnosed bone tumor included malignant giant cell tumors of bone (2.8%, 10/357) and fibrous dysplasia of bone (1.7%, 6/357). Meanwhile, we found that the mutations of MUC16 may be a potential biomarker for the diagnosis of mesenchymal chondrosarcomas. Our results indicated that RNA sequencing effectively complements DNA sequencing and increased the detection rate of gene fusions, supporting that NGS technology can effectively assist the diagnosis of bone tumors.

A novel limb-salvage reconstruction strategy with a custom hemipelvic endoprosthesis and preserved femoral head following the resection of periacetabular tumors: A preliminary study.

The treatment of periacetabular malignancy frequently challenges surgeons. To simplify the surgical procedure, we performed a novel reconstruction strategy preserving the femoral head for patients with periacetabular malignancies. We retrospectively reviewed 14 patients who underwent total en bloc resection of a periacetabular tumor and reconstruction of the hip joint with an individualized hemipelvic endoprosthesis and remaining femoral head from July 2015 to January 2019 at our center. Regions of pelvic resection: region II-4 (28.6%), region I + II-5 (35.7%), region II + III-2 (14.3%) and region I + II + III-3 (21.4%). The oncological outcomes were that 13 patients survived without disease and one patient survived with lung metastasis. None of the patients experienced local recurrence (range: 20-62 months; mean: 32 months). The incidence of postoperative complications was 35.7%, including delayed wound healing and deep venous thrombosis. No prosthesis-related complications occurred until the last follow-up in this study (range: 20-62 months; mean: 32 months). The mean Musculoskeletal Tumor Society functional outcome score was 23.2. The mean Toronto Extremity Salvage Score of the patients was 75.7 points, with a mean limb discrepancy of 1.51 cm (range: 0.5-3.2 cm). Reconstruction with preservation of the femoral head showed acceptable early functional and oncological outcomes, and it had an acceptable complication rate.

Construction of survival-related co-expression modules and identification of potential prognostic biomarkers of osteosarcoma using WGCNA.

Background: Osteosarcoma (OS) is a primary malignant bone tumor. Patients with different immune characteristics respond differently to chemotherapy and have a lower chance of survival. The potential pathogenesis and therapeutic targets of OS must be investigated further. Methods: OS expression profile data and clinical information were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and the Gene Expression Omnibus (GEO) databases. The immune-related gene set was obtained from the ImmPort database, and the immune-related gene expression profiles were used for non-negative matrix factorization (NMF) cluster analysis of patients in the 2 databases to find the best clustering number. In the TARGET database, OS patients were classified into low-risk and high-risk groups based on the differences in their survival rates. Weighted correlation network analysis (WGCNA) was applied to the low-risk and high-risk groups to determine the module with the lowest conservatism in order to differentiate the prognosis of the 2 groups. Results: A total of 500 key genes associated with poor prognosis were identified. Gene Ontology (GO) enrichment analysis revealed that the biological processes of these genes were primarily focused on the regulation of small guanosine triphosphatase (GTPase) mediated signal transduction, collagen-containing extracellular matrix, and Rho GTPase binding. A random survival forest identified EPHB3, TEAD1, and KRR1P1 as key genes. Their expression level was linked to overall survival. We discovered that the core genes were associated to immune cell infiltration. Simultaneously, paired survival analysis of two genes revealed differences in survival. We also reverse-predicted the main genes and developed their competitive endogenous RNA (ceRNA) network. Finally, utilizing the CellMiner database, we observed that the genes TEAD1 and EPHB3 were connected to drug sensitivity. Conclusions: In this study, we identified the modules and key genes related to the poor prognosis of OS patients by using WGCNA, and verified their impact on the prognosis of OS patients and their role in the immune microenvironment of OS. In addition, targeted gene related antitumor drugs were screened out. The discoveries may lead to novel molecular targets and treatment methods for OS patients. Keywords: Osteosarcoma (OS); weighted gene co-expression network analysis (WGCNA); gene.

Hereditary retinoblastoma iPSC model reveals aberrant spliceosome function driving bone malignancies.

The RB1 gene is frequently mutated in human cancers but its role in tumorigenesis remains incompletely defined. Using an induced pluripotent stem cell (iPSC) model of hereditary retinoblastoma (RB), we report that the spliceosome is an up-regulated target responding to oncogenic stress in RB1-mutant cells. By investigating transcriptomes and genome occupancies in RB iPSC­derived osteoblasts (OBs), we discover that both E2F3a, which mediates spliceosomal gene expression, and pRB, which antagonizes E2F3a, coregulate more than one-third of spliceosomal genes by cobinding to their promoters or enhancers. Pharmacological inhibition of the spliceosome in RB1-mutant cells leads to global intron retention, decreased cell proliferation, and impaired tumorigenesis. Tumor specimen studies and genome-wide TCGA (The Cancer Genome Atlas) expression profile analyses support the clinical relevance of pRB and E2F3a in modulating spliceosomal gene expression in multiple cancer types including osteosarcoma (OS). High levels of pRB/E2F3a­regulated spliceosomal genes are associated with poor OS patient survival. Collectively, these findings reveal an undiscovered connection between pRB, E2F3a, the spliceosome, and tumorigenesis, pointing to the spliceosomal machinery as a potentially widespread therapeutic vulnerability of pRB-deficient cancers.

Medication therapy of high-dose methotrexate: An evidence-based practice guideline of the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society.

AIMS: A lot of medication risks related to high-dose methotrexate (HDMTX) therapy still remain to be identified and standardized. This study aims to establish an evidence-based practice guideline for individualized medication of HDMTX. METHODS: The practice guideline was launched by the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society. The guideline was developed following the WHO handbook for guideline development and the methodology of evidence-based medicine (EBM). The guideline was initially registered in the International Practice Guidelines Registry Platform (IPGRP-2017CN021). Systematic reviews were conducted to synthesize available evidence. A multicentre cross-sectional study was conducted using questionnaires to evaluate patients' perception and willingness concerning individualized medication of HDMTX. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to rate the quality of evidence and to grade the strength of recommendations. RESULTS: Multidisciplinary working groups were included in this guideline, including clinicians, pharmacists, methodologists, pharmacologists and pharmacoeconomic specialists. A total of 124 patients were involved to integrate patient values and preferences. Finally, the guideline presents 28 recommendations, regarding evaluation prior to administration (renal function, liver function, pleural effusion, comedications, genetic testing), pre-treatment and routine dosing regimen, therapeutic drug monitoring (necessity, method, timing, target concentration), leucovorin rescue (initial timing, dosage regimen and optimization), and management of toxicities. Of these, 12 are strong recommendations. CONCLUSIONS: We developed an evidence-based practice guideline with respect to HDMTX medication using a rigorous and multidisciplinary approach. This guideline provides comprehensive and practical recommendations involving the whole process of HDMTX administration to health care providers.

Survival after pulmonary metastasectomy for relapsed osteosarcoma.

OBJECTIVES: The purpose of this study was to evaluate the postrelapse survival of relapsed osteosarcoma with pulmonary metastases in patients who received pulmonary metastasectomy using intent to treat and propensity score analysis. METHODS: Patients with osteosarcoma who relapsed with pulmonary metastases between 2004 and 2018 who were treated in a hospital affiliated with a medical school were included. All the enrolled patients were evaluated as operable with assessment algorithm at the time of diagnosis of pulmonary relapse and intent to treat analysis was done. Multiple propensity score methods (eg, matching, stratification, covariate adjustment, and inverse probability of treatment weighting) were performed to balance confounding bias. Cox proportional hazards regression and the Kaplan-Meier method were used to evaluate patient survival. RESULTS: A total of 125 patients met the study criteria. Of these, 59 (47.2%) patients received pulmonary metastasectomy combined with chemotherapy and 66 (52.8%) received chemotherapy alone. The 2-year and 5-year postrelapse survival rate of metastasectomy group and nonmetastasectomy group were 68.4% versus 25.0% and 41.0% versus 0%, respectively. The median postrelapse survival was 24.9 versus 13.5 months, respectively. Pulmonary metastasectomy was independently associated with improved survival (hazard ratio, 0.185; 95% confidence interval, 0.103-0.330; P < .001). These results were confirmed by multiple propensity score analyses. Further stratified analysis revealed that the survival advantage associated with metastasectomy was not significant in patients with metastases involving ≥3 lung lobes and patients with very high pretreatment serum alkaline phosphatase (more than twice the upper limit). CONCLUSIONS: Pulmonary metastasectomy is associated with improved survival in patients with recurrent osteosarcoma.

Cordycepin augments the chemosensitivity of osteosarcoma to cisplatin by activating AMPK and suppressing the AKT signaling pathway.

BACKGROUND: Osteosarcoma is the most common primary bone tumor in children and adolescents. However, some patients with osteosarcoma develop resistance to chemotherapy, leading to a poor clinical prognosis. Hence, effective therapeutic agents that can improve the response to chemotherapy drugs to improve the prognosis of patients with osteosarcoma are urgently needed. Cordycepin has recently emerged as a promising antitumor drug candidate. This study aims to explore the effect of cordycepin in suppressing osteosarcoma in vivo and in vitro and the synergistic effect of cordycepin combined with cisplatin and to demonstrate the underlying molecular mechanism. METHODS: CCK-8 assay was performed to investigate the inhibition effect of cordycepin combined with cisplatin in osteosarcoma cell lines. The colony formation and invasion abilities were measured by colony formation assay and Transwell assay. Osteosarcoma cells apoptosis was detected by flow cytometry. Western blot analysis were used to detect the expression of cell apoptosis-related proteins and AMPK and AKT/mTOR signaling pathway-related proteins. Finally, we performed the in vivo animal model to further explore whether cordycepin and cisplatin exert synergistic antitumor effects. RESULTS: Notably, we found that treatment with cordycepin inhibited cell proliferation, invasion, and induced apoptosis in osteosarcoma cells in vitro and in vivo. Moreover, the combination of cordycepin and cisplatin led to marked inhibition of osteosarcoma cell proliferation and invasion and promoted osteosarcoma cell apoptosis in vitro and in vivo. Mechanistically, we demonstrated that cordycepin enhanced the sensitivity of osteosarcoma cells to cisplatin by activating AMPK and inhibiting the AKT/mTOR signaling pathway. CONCLUSIONS: In brief, this study provides comprehensive evidence that cordycepin inhibits osteosarcoma cell growth and invasion and induces osteosarcoma cell apoptosis by activating AMPK and inhibiting the AKT/mTOR signaling pathway and enhances the sensitivity of osteosarcoma cells to cisplatin, suggesting that cordycepin is a promising treatment for osteosarcoma.

GTSE1 is possibly involved in the DNA damage repair and cisplatin resistance in osteosarcoma.

BACKGROUND: G2 and S phase-expressed-1 (GTSE1) negatively regulates the tumor-suppressive protein p53 and is potentially correlated with chemoresistance of cancer cells. This study aims to explore the effect of GTSE1 on the DNA damage repair and cisplatin (CDDP) resistance in osteosarcoma (OS). MATERIALS AND METHODS: Expression of GTSE1 in OS was predicted in bioinformatics system GEPIA and then validated in clinically obtained tissues and acquired cell lines using RT-qPCR, immunohistochemical staining, and western blot assays. Gain- and loss-of-function studies of GTSE1 were performed in MG-63 and 143B cells to examine its function in cell cycle progression, DNA replication, and CDDP resistance. Stably transfected MG-63 cells were administrated into mice, followed by CDDP treatment to detect the role of GTSE1 in CDDP resistance in vivo. RESULTS: GTSE1 was highly expressed in patients with OS and correlated with poor survival according to the bioinformatics predictions. Elevated GTSE1 expression was detected in OS tissues and cell lines. GTSE1 silencing reduced S/G2 transition and DNA replication, and it increased the CDDP sensitivity and decreased the expression of DNA repair-related biomarkers in MG-63 cells. GTSE1 overexpression in 143B cells led to inverse trends. In vivo, downregulation of GTSE1 strengthened the treating effect of CDDP and significantly repressed growth of xenograft tumors in nude mice. However, overexpression of GTSE1 blocked the anti-tumor effect of CDDP. CONCLUSION: This study demonstrates that GTSE1 is possibly involved in the DNA damage repair and cisplatin resistance in OS.