Maintaining telomere integrity is essential for cellular survival, and reactivation of telomerase or alternative lengthening of telomeres (ALT) represents a hallmark of cancer, ensuring replicative immortality. Osteosarcoma (OS), a malignancy in which many tumors rely on ALT for telomere maintenance, lacks effective therapeutic strategies targeting this pathway. This study aimed to identify and characterize novel molecular regulators of ALT activity and explore their potential as therapeutic targets in OS. Methods: Immunohistochemistry was performed to evaluate the expression of phosphorylated NPM1 (pT199-NPM1) in OS tissues. Functional experiments including NPM1 knockdown and rescue assays were conducted to assess the impact of NPM1 on break-induced telomere replication (BITR) and cell viability in ALT-positive cells. Mechanistic studies involving phosphorylation analysis, ubiquitination assays, and co-immunoprecipitation were used to determine how ATR-mediated phosphorylation of NPM1 regulates POLD3 stability and its interaction with the CST complex. Pharmacological screening was performed to identify compounds that inhibit ALT activity, followed by in vitro proliferation assays and in vivo mouse xenograft experiments to evaluate therapeutic efficacy and synergy with doxorubicin. Results: We identified pT199-NPM1 as a novel, highly expressed protein factor in ALT-positive OS tissues. NPM1 depletion impaired break-induced telomere replication and significantly reduced the viability of ALT-positive cells. ATR signaling phosphorylated NPM1 at Thr199, which stabilized POLD3 by preventing its ubiquitin-mediated degradation. Recruitment and function of pT199-NPM1 at telomeric damage sites required STN1, defining a CST/pT199-NPM1/POLD3 regulatory axis essential for ALT activity. Clinically, elevated Thr199 phosphorylation correlated with poor survival in OS patients, while expression of a phosphorylation-deficient T199A mutant failed to sustain ALT telomere maintenance. Pharmacological screening identified EPZ-6438, an EZH2 inhibitor, as a potent ALT suppressor that reduced NPM1 transcription, inhibited homologous recombination-mediated telomere synthesis, and suppressed OS cell proliferation. In mouse xenografts, EPZ-6438 enhanced OS cell sensitivity to doxorubicin, suggesting therapeutic synergy. Conclusions: This study uncovers a novel CST/pT199-NPM1/POLD3 regulatory module that is critical for ALT telomere maintenance in OS. Targeting NPM1 or its downstream effectors effectively suppresses ALT activity and enhances chemotherapy response. These findings provide new mechanistic insights into telomere regulation in ALT-positive tumors and highlight the therapeutic potential of NPM1-centered pathways in OS.

Tropomyosin receptor kinases (TRK) tyrosine kinase inhibitors (TKIs) have demonstrated marked efficacy in neurotrophic receptor tyrosine kinase (NTRK) fusion positive tumors. However, resistance inevitably develops. Eratrectinib (VC004) is a next-generation selective TRK TKI which can overcome drug resistance. In this phase 1 study, patients with locally advanced or metastatic solid tumors were enrolled in the dose-escalation part. A standard 3 + 3 design was adopted to sequentially assign patients at 25 mg twice daily (BID), 50 mg BID, 100 mg BID, and 200 mg BID dose levels of oral eratrectinib. After each dose had been established, we expanded specific dose cohorts in patients with NTRK fusion positive locally advanced or metastatic solid tumors to obtain adequate data for safety, pharmacokinetics (PK), and efficacy. The primary endpoints of this study were safety, maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Between December 4, 2020 and November 4, 2021, 16 patients were enrolled in the dose-escalation part and a dose of 100 mg BID was identified as MTD. Between May 8, 2021 and March 19, 2025, 75 patients were enrolled in the dose-expansion part at doses of eratrectinib 25 mg BID, 50 mg BID, and 75 mg BID. Treatment-emergent adverse events (TEAEs) occurred in 94.7

INTRODUCTION:Osteosarcoma is a highly aggressive cancer with a notably low five-year survival rate. Although aspirin has demonstrated potential in inhibiting the malignant progression of osteosarcoma, the underlying mechanisms remain unclear. METHODS:In this study, RNA sequencing (RNA-seq) was employed to identify the downstream targets of aspirin in osteosarcoma cells. Then, we examined the expression and clinical significance of PDE4D using osteosarcoma patient samples, tissue microarrays, and data from the TARGET and GTEx databases. The effects of PDE4D on cell growth and mobility were assessed by CCK-8, colony formation, transwell, and wound-healing assays. To explore how aspirin influenced the NF-κB/p65/PDE4D axis, we performed qRT-PCR, Western blotting, luciferase reporter assays, etc. Additionally, mouse models with subcutaneous tumors were used to confirm the roles of aspirin and PDE4D. RESULTS:Our results showed that aspirin significantly impeded the proliferation, migration, and invasion of osteosarcoma cells by various functional assays. RNA-seq identified PDE4D as a key target modulated by aspirin treatment in osteosarcoma. Clinically, PDE4D was highly expressed in osteosarcoma cells and tissues, and higher levels of PDE4D were linked to poorer patient outcomes. Functionally, PDE4D served as an oncogene that promoted the malignant traits of osteosarcoma both in vitro and in vivo. Mechanistically, our findings revealed that NF-κB/p65 directly interacted with the core region of the PDE4D promoter, increasing its expression. DISCUSSION:The findings of this study reveal a novel mechanism whereby aspirin exerts its anti-tumor effects by inhibiting the NF-κB/p65/PDE4D axis, providing a mechanistic basis for its therapeutic potential. Further validation in different animal models of osteosarcoma is warranted. CONCLUSION:Aspirin suppressed the malignant progression of osteosarcoma by targeting the NF-κB/p65/PDE4D axis, positioning PDE4D as a potential therapeutic target for aspirin- based treatment strategies.

Multiple myeloma(MM)is a clonal plasma cell malignancy that arises within the bone marrow(BM),leading to disrup-tions in normal hematopoiesis,immune dysfunction,oste-olytic bone lesions,anemia,and renal impairment1.

Abstract Background The role of extrachromosomal DNA (ecDNA)-related genes in osteosarcoma remains largely unexplored. The aim of this study is to investigate the association between ecDNA-related genes and prognosis and tumor microenvironment (TME) in osteosarcoma. Methods Differential gene expression analysis of GEO datasets was conducted to identify ecDNA-related genes in osteosarcoma. Based on bulk RNA-seq data, a novel ecDNA-related Gene Prognostic Score Model (EGPSM) was developed using an integrated framework of 101 machine learning algorithms, which was validated in training, testing, and external cohorts. The associations between risk scores, prognosis, and TME characteristics were comprehensively evaluated. Single-cell RNA sequencing (scRNA-seq) data were further analyzed to elucidate the relationship between EGPSM, pro-tumor behaviors, and immune modulation in osteosarcoma, as well as to identify key prognostic genes involved in tumor progression. Lastly, we conducted in vitro and in vivo assays to characterize the biological roles of MTDH and to elucidate its regulatory effects on CD8⁺ T cell function. Results A robust EGPSM was constructed, demonstrating superior predictive accuracy with a maximum C-index of 0.803. High-risk patients exhibited poorer survival, higher metastatic potential, and an "immune-cold" TME characterized by diminished CD8⁺ T/NK cell infiltration and impaired effector functions. Single-cell analysis confirmed the enrichment of malignant cells and depletion of T/NK populations with lower effector scores in the high-risk group. MTDH was identified as a key driver; functional assays showed it promotes proliferation and invasion while inhibiting apoptosis. Notably, MTDH knockdown potentiated CD8⁺ T-cell cytotoxicity by increasing the levels of granzyme B, IFN-γ, and perforin. Conclusion The newly developed EGPSM represents an effective tool for prognostic assessment and therapeutic stratification in osteosarcoma. MTDH may serve as a promising prognostic biomarker and therapeutic target.

T-box transcription factor 20 (TBX20) serves a crucial regulatory role in the process of tumor occurrence. In lung cancer, the upregulation of TBX20 expression is positively associated with a poor prognosis; however, the specific underlying mechanism remains unclear. Therefore, in the present study, the expression of TBX20 in normal lung epithelial BEAS-2B and cancer cells A549 was detected by quantitative PCR and western blot. Lung cancer cell lines with overexpression and interference of TBX20 were constructed. Cell proliferation was detected by Cell Counting Kit-8, cell migration and invasion were detected by Transwell, and cell spheroid formation was assessed. The expression of EMT markers (E-cadherin, N-cadherin, vimentin), stemness markers (CD44, Sox2, Nanog), and immune factors (PD-L1, IL-6, CCL2) was detected by qPCR and WB. A subcutaneous lung cancer model in nude mice was established. After 4 weeks, the tumor volume was observed. The expression of E-cadherin, N-cadherin, vimentin, CD44, and PD-L1 in tumor tissues was detected by IHC. The infiltration of immune cells (CD8+T, CD4+T, M1/M2 macrophages) was detected by flow cytometry. In vitro experiments revealed that the expression levels of TBX20 were increased in the A549 lung cancer cells compared with those in BEAS-2B normal lung epithelial cells. In addition, cell viability, migration, invasion and spheroid formation capacity were greater in the A549 group than in the BEAS-2B group. Compared with in the negative control (NC) group, the TBX20 overexpression plasmid (oe-TBX20) group exhibited enhanced cell viability, migration, invasion and spheroid formation capacity. Furthermore, E-cadherin expression was reduced, whereas N-cadherin, vimentin, Sox2, CD44, Nanog, PD-L1, IL-6 and CCL2 expression levels were elevated. Notably, these changes were reversed in the TBX20 knockdown group. In vivo experiments revealed that compared with in the NC group, the oe-TBX20 group had significantly increased tumor volume, decreased E-cadherin levels, and elevated expression levels of TBX20, N-cadherin, vimentin, CD44 and PD-L1. Compared with NC group, the oe-TBX20 group exhibited significantly lower infiltration of CD4+ T and CD8+ T cells and M1-type macrophage, whereas that of M2-type macrophages and regulatory T cells increased. Conversely, these indicators were reversed in the short hairpin RNA-TBX20 group. In conclusion, TBX20 may induce epithelial-mesenchymal transition and stem cell characteristics, enhance the malignant behavior of lung cancer cells, and upregulate PD-L1 expression to promote immune escape.

BackgroundOsteosarcoma is a highly aggressive bone malignancy characterized by frequent metastasis and therapy resistance. Although mitophagy and pyruvate metabolism are increasingly recognized as critical metabolic regulators, their interaction in osteosarcoma remains poorly understood. The autophagy-related protein GABARAP, central to mitochondrial quality control, has not been systematically evaluated in osteosarcoma.MethodsSingle-cell RNA sequencing (scRNA-seq) datasets (GSE162454, GSE237070) were analyzed to delineate cellular heterogeneity and malignant states, with prognostic clusters identified by Scissor and inferCNV. Tumor microenvironment (TME) composition and intercellular signaling were profiled using CellChat. Pathway enrichment and multi-omics integration across TARGET, GSE21257, and GSE32981 highlighted mitophagy-pyruvate coupling, which were further validated by spatial transcriptomics and in vitro functional assays.ResultsWe mapped the osteosarcoma ecosystem and identified two malignant subpopulations, Ost_1 and Cho_2 (Mal_Ost/Cho), exhibiting high genomic instability, stemness, and poor prognosis. The osteosarcoma TME displayed profound immune remodeling, characterized by infiltration of T/NK cells alongside enrichment of immunosuppressive Tregs and M2-polarized macrophages. Enhanced MIF-mediated signaling between Mal_Ost/Cho and T/NK compartments suggested a key mechanism of immune evasion. Both malignant subtypes demonstrated coordinated activation of mitophagy and pyruvate metabolism, sustaining metabolic adaptation and tumor progression. Multi-omics integration pinpointed GABARAP as a central hub regulating this mitophagy-metabolism axis, spatially enriched within metabolic hotspots and immunosuppressive niches. Functionally, GABARAP depletion disrupted mitophagy flux, mitochondrial integrity, and energy production, thereby impairing osteosarcoma cell proliferation and migration.ConclusionThese findings reveal that GABARAP links mitophagy-driven metabolic adaptation with immune evasion, representing a key regulator and potential therapeutic target in osteosarcoma.

11509 Background: There was limited therapeutic advancement for decades for patients (pts) with relapsed and refractory (R/R) osteosarcoma. Pts with R/R osteosarcoma urgently need effective and safe treatment options after standard therapy failure. ALMB-0168, a first-in-class humanized IgG4 monoclonal antibody targeted to hemichannel protein Cx43, activates hemichannels to release key substances including ATP into the extracellular environment, to inhibit the growth and migration of osteosarcoma and other cancers bone metastases. Here reported the phase 2 study result based on ASCO 2023 Poster (11530). Methods: Pts ≥ 12 years (yrs) with pathologically confirmed osteosarcoma who had failed standard therapy were enrolled. In the phase I dose escalation with an accelerated titration followed by 3+3 design, pts were dosed with 7 planned ALMB-0168 dose levels (1, 3, 6, 12, 18, 24, and 30mg/kg), Q3W, until their disease progressed or intolerable toxicity occurred. Then the cohort at effective dose 6mg/kg was expanded. This trial used RECIST1.1 for efficacy evaluation. Primary endpoints were safety and tolerability. Key secondary endpoints were overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS). The CD73/CD39 expressions evaluated by IHC in osteosarcoma FFPE tissue with the efficacy were retrospectively analyzed. Results: As of Aug 19, 2024, total 27 pts with median age 29 yrs (range 16–69 yrs) were enrolled, of which 17 pts for dose escalation and 10 for dose expansion at 6mg/kg. No dose-limiting toxicity was observed. Treatment related adverse events (TRAEs) of any grade occurred in 18 (66.7%) pts, most of them were grade 1-2. Grade 3 TRAEs occurred in 1 (3.7%) patient (infectious pneumonia); no events were Grade 4 or 5. Common TRAEs observed in ≥ 10% pts were anemia (22.2%), proteinuria (14.8%) and alpha hydroxybutyrate dehydrogenase increased (11.1%). The DCR of whole evaluable pts was 68.2% (15/22), including 3 PR and 12 SD. At the 6mg/kg dose level which was expanded, among 10 evaluable pts, 2 pts achieved partial response (ORR: 20%), of which 1 patient achieved durable PR for 17 months (mo), PFS for 23 mo and OS for 36 mo (not reached). In 6mg/kg group, the DCR was 90% (9/10, 95% CI: 55.5, 99.7%) with 2 PR and 7 SD. And the PFS rate of 6mg/kg group at 4th mo was 70% (95% CI: 22.48, 91.83%). The relationship between the efficacy and the CD73/CD39 expression and other exploratory results will be presented in the future. Conclusion: The maximum tolerated dose of ALMB-0168 was not reached. The recommended phase 2 dose is 6mg/kg. In this study, ALMB-0168 showed encouraging anti-tumor activity, safe profile and durable benefit for pts with R/R osteosarcoma, which might be one of the potential treatment options for R/R osteosarcoma in the future. Clinical trial information: NCT04886765 .

Chemoresistance is a major factor contributing to the poor prognosis of osteosarcoma. Increasing evidence underscores the pivotal role of enhanced tumor stemness in driving drug resistance. In this study we investigated the molecular mechanisms underlying the chemoresistance and stemness in osteosarcoma. Two cisplatin-resistant osteosarcoma cell line models (U2OS-DDPr and 143B-DDPr) were established by culturing parental U2OS and 143B cells with escalating cisplatin concentrations (250 ng/mL to 2.5 µg/mL) over a 6-month period. We found that the expression levels of suppressor of cytokine signaling 1 (SOCS1), an E3 ubiquitin ligase, were markedly downregulated in both chemo-resistant osteosarcoma cells and osteosarcoma tumor specimens, and the reduced expression in tumor specimens was correlated to poor prognosis in osteosarcoma patients. Silencing SOCS1 significantly reduced cisplatin sensitivity, enhanced spheroid formation capacity, and upregulated the expression of stem cell markers including SOX2, OCT4, and CD44. Conversely, restoring SOCS1 expression reversed these effects both in vitro and in vivo. Immunoprecipitation-mass spectrometry analysis revealed that SOCS1 bound to ACTN4 and suppressed its protein expression by promoting K63-linked ubiquitination, ultimately leading to proteasomal degradation. Specifically, the SH2 domain of SOCS1 interacted with the N-terminal region of ACTN4, with Lys66 of ACTN4 playing a critical role in facilitating this interaction and subsequent ubiquitination. In addition, the expression of ACTN4 was highly enriched in chemo-resistant tissues, and its overexpression was positively associated with advanced tumor staging. Importantly, ACTN4 functioned as an oncogene to promote cisplatin resistance and stemness in osteosarcoma. Furthermore, we found that wortmannin, an inhibitor of ACTN4, could markedly block the effect of SOCS1 silencing on osteosarcoma aggressiveness. In conclusion, SOCS1 deletion promotes stemness and chemoresistance in osteosarcoma by inhibiting ACTN4 ubiquitination and degradation, which offers promising therapeutic targets for potentiating chemosensitivity in osteosarcoma.

Chemoresistance remains the main obstacle limiting the treatment of osteosarcoma, seriously affecting the prognosis of adolescent patients with osteosarcoma. Recently, long non-coding RNAs (lncRNAs) were reported to be involved in chemoresistance, while the mechanisms of lncRNAs underlying osteosarcoma resistance to chemotherapy remain elusive. Here, LINC00520 was identified as a novel cisplatin resistance-related lncRNA in osteosarcoma, and its high expression was associated with poor prognosis of osteosarcoma patients. Functionally, LINC00520 could potentiate osteosarcoma resistance to cisplatin in vitro and in vivo. Mechanistically, LINC00520 bound to ENO1 and upregulated ENO1 protein expression by blocking FBXW7-mediated ENO1 ubiquitination and proteasomal degradation, thereby promoting glycolysis and ultimately inducing cisplatin resistance in osteosarcoma. Furthermore, METTL3 could stabilize and upregulate LINC00520 in an m6A-YTHDF2-dependent manner in osteosarcoma. This study proposes a novel lncRNA-driven mechanism for cisplatin resistance in osteosarcoma, and offers a promising therapeutic strategy for reversing chemoresistance in osteosarcoma by targeting the METTL3/LINC00520/ENO1/glycolysis axis.

BackgroundHepatocellular carcinoma (HCC) is one of the most prevalent causes of cancer-related morbidity and mortality worldwide. Late-stage detection and the complex molecular mechanisms driving tumor progression contribute significantly to its poor prognosis. Dysregulated R-loops, three-stranded nucleic acid structures associated with genome instability, play a key role in the malignant characteristics of various tumors. However, the detailed role and mechanism of R-loops in HCC progression remain elusive and require further exploration. This study aimed to construct an R-loop scoring signature centered on prognosis and lipid metabolism, thereby enhancing our understanding of HCC progression and identifying potential therapeutic targets.MethodsIn this study, we utilized the single-cell RNA-sequencing (scRNA-seq) data from HCC patients (GSE149614 and CRA002308) to construct an R-loop scoring model based on the identified R-loop regulator genes (RLRGs) related to HBV infection through WGCNA analysis. We also explored the tumor microenvironment and intercellular communication related to R-loop score. Additionally, a prognostic risk model based on the fatty acid metabolism-associated RLRGs was constructed using data from the TCGA database, and its association with immune infiltration, mutations, and drug sensitivity was analyzed. In vitro and in vivo experiments were performed to investigate the role of RLRG CLTC in lipid metabolism and HCC progression.ResultsUsing scRNA-seq data from HCC, we established an R-loop scoring model based on identified RLRGs related to HBV infection. Moreover, the more suppressive tumor immune microenvironment and stronger intercellular communication were displayed in malignant cells with high R-loop scores. The cell trajectory and cellular metabolism analysis exhibited a significant association between lipid metabolism and RLRGs. Additionally, we constructed a prognostic risk model consisting of 8 RLRGs related to fatty acid metabolism, which effectively evaluated the prognostic value, status of tumor immune microenvironment, gene mutations, and chemotherapeutic drug sensitivity for HCC patients. Notably, validation experiments suggested that CLTC could regulate lipid metabolism through R-loop formation and facilitate tumor progression in HCC.ConclusionCollectively, our study proposes an R-loop scoring model associated with tumor immune microenvironment, lipid metabolism and prognostic value. CLTC, an R-loop regulator, emerges as a promising prognostic biomarker and therapeutic target, offering new insights into potential treatment strategies for HCC patients.

Supplementary materials and methods, Supplementary figures, Supplementary figure legends, Supplementary tables

Objective: The aim of our study was to explore the effect of IORT on survival outcome of patients with musculoskeletal malignancy. The prognostic factors of patients with IORT treatment were also identified in this study. Methods: The retrospective analysis was conducted based on the Surveillance, Epidemiology, and End Results (SEER) database spanning from 2000 to 2020. The musculoskeletal malignancy patients who received both surgery and radiation therapy (RT) treatment were included into the study. Survival differences between groups were explored by Kaplan-Meier method and log-rank test. Potential prognostic factors of patients with IORT treatment were identified by Cox proportional hazards regression analysis. Results: A total of 24,297 patients were selected finally, including 23,877 cases with neoadjuvant/adjuvant RT alone, 190 cases with IORT alone, and other 230 cases received both neoadjuvant/adjuvant RT and IORT. The median survival time of these patients was 141.0 (95%CI: 101.1-180.9) months. Patients who received both IORT and neoadjuvant/adjuvant RT treatment presented the best survival outcome when compared with those underwent either IORT or neoadjuvant/adjuvant RT only. Further subgroup analyses verified the survival benefit of the combination of IORT and neoadjuvant/adjuvant RT in female patients with tumor located on limb and in patients who received the performance of chemotherapy. A series of variables, including age at diagnosis, gender, primary tumor site, tumor Grade, SEER stage, T stage, N stage, IORT only or the combination of IORT and neoadjuvant/adjuvant RT, the performance of chemotherapy, were identified as independent prognostic factors of patients with IORT treatment. Conclusions: The current study is distinguished by its large-scale analysis of the SEER database, encompassing a comprehensive cohort of musculoskeletal malignancy patients treated with IORT, as well as the rigorous subgroup analysis. We concluded that IORT during surgery procedure, accompanied with neoadjuvant/adjuvant RT, might confer a survival benefit for selected patients diagnosed with musculoskeletal malignancy.

11507 Background: Patients (pts) with relapsed and refractory (R/R) osteosarcoma have a poor prognosis with limited therapeutic options. HS-20093 is a novel antibody-drug conjugate (ADC) targeting B7-H3, which showed preliminary anti-tumor activity in phase 1 ARTEMIS-001 study (NCT05276609). Here we report results in R/R osteosarcoma pts treated with HS-20093 from ARTEMIS-002 study (NCT05830123). Methods: ARTEMIS-002 trial is an open label, two-arm phase 2 trial in pts with R/R osteosarcoma or other sarcomas progressed upon standard systemic treatment. Based on the results of the phase 1 trial that the maximum tolerated dose was 12 mg/kg once every 3 weeks (Q3W) intravenous infusion, the osteosarcoma pts in the phase 2 trial were randomized to receiving HS-20093 either at 8 mg/kg or 12 mg/kg Q3W at a ratio of 1:1. The primary endpoint was objective response rate (ORR) according to RECIST1.1. B7-H3 expression was retrospectively evaluated by IHC in osteosarcoma FFPE tissue. Results: A total of 34 pts with R/R osteosarcoma were enrolled from June to December in 2023, receiving HS-20093 at the dose of either 8.0 mg/kg (N = 15) or 12.0 mg/kg (N = 19). Median age was 21.5 years (range: 18~65). At baseline, most pts were evaluated with clinical stage IV disease (32/34, 94.1%) and pulmonary metastasis (28/34, 82.4%). Twenty-two pts (64.7%) had received ≥3 prior lines therapy. Twenty-six pts (76.5%) had received 4 types of standard chemotherapies consisting of platinum, anthracyclines, ifosfamide and methotrexate. Treatment emergent adverse event (TEAEs) occurred in 33 pts (97.1%). The common grade 3/4 TEAEs (≥5%) were: neutropenia, leukopenia, thrombocytopenia, lymphopenia and anemia. The incidences of discontinuations, dose withhold and dose reductions were 2.9%, 11.8% and 23.5%, respectively. There was no TEAE leading to death. As of cut-off date (25 December, 2023), the median follow-up time was 4.1 months (95% CI: 1.4~5.5) among 21 response-evaluable pts (11 treated with 8 mg/kg and 10 with 12.0 mg/kg). The ORR of 12.0 mg/kg HS-20093 was 20.0%. Two confirmed partial responses were observed in pts with 12.0 mg/kg and remained on response until last follow-up, of which the longest duration of response was 4.0 months. The disease control rate was 81.8% (9/11) and 100% (10/10) in pts with 8 mg/kg and 12.0 mg/kg. The median progression-free survival of all 21 pts was not mature. B7-H3 is highly expressed in osteosarcoma with median H-score 185 (0~260). No correlation was observed between tumor response and B7-H3 expression level. The PK exposure of HS-20093 ADC, total Ab and payload increased with dose, approximately proportional to dose, with a half-life of 4 to 6 days, and no or minor accumulation after multiple doses of Q3W. Conclusions: The data has demonstrated that HS-20093 exhibited promising antitumor activity with acceptable toxicity in pts of heavily-pretreated R/R osteosarcoma. The enrollment of ARTEMIS-002 is continuing. Clinical trial information: NCT05830123 .

BACKGROUND:Osteosarcoma is the most familiar primary malignant tumor occurred in bone in young people and is featured by complicated genetic changes. CD93 has been affirmed to exhibit the facilitative roles in multiple cancers. METHODS:But, the detailed impacts and related regulatory pathway of CD93 in osteosarcoma progression maintain unclear. RESULTS:In this study, the elevated expression of CD93 was verified in osteosarcoma tissues from GEO database. Additionally, it was illustrated that CD93 existed the aggrandized mRNA and protein expressions in osteosarcoma cell lines. Moreover, suppression of CD93 restrained cell proliferation and angiogenesis in osteosarcoma. It was demonstrated that inhibition of CD93 retarded immune escape in osteosarcoma. Furthermore, CD93 triggered the PI3K/AKT pathway to aggravate the progression of osteosarcoma. At last, it was discovered that knockdown of CD93 attenuated tumor growth in vivo. CONCLUSIONS:In conclusion, this study disclosed that CD93 aggravated cell proliferation, angiogenesis and immune escape in osteosarcoma through triggering the PI3K/AKT pathway. This work may supply useful opinions of CD93 on the cure of osteosarcoma.

BACKGROUND:Osteosarcoma is a prevalent malignant tumor that originates from mesenchymal tissue. It typically affects children and adolescents. Although it is known that the growth of osteosarcoma relies on oxidative phosphorylation for energy production, limited attention has been paid to exploring the potential of oxidative phosphorylation-related genes in predicting the prognosis of individuals suffering from osteosarcoma. METHODS:All the data were retrieved from the UCSC Xena and GEO (GENE EXPRESSION OMNIBUS). Identification of the oxidative phosphorylation genes linked to the prognosis of individuals with osteosarcoma was done by means of univariate COX and LASSO regression analyses. Following that, patients were categorized into a high-risk group and a low-risk group as per the risk score determined by the identified oxidative phosphorylation genes. Furthermore, a comparison was made in terms of the survival and immune infiltration between both groups, and the prognostic model was established. RESULTS:Five oxidative phosphorylation genes (ATP6V0D1, LHPP, COX6A2, MTHFD2, NDUFB9) associated with the prognosis of individuals with osteosarcoma were identified and the risk prognostic models were constructed. In the current research, the analysis of the ROC curves indicated a superior predictive accuracy exhibited by the risk model. The prognosis was adversely affected by immune infiltration in the high-risk group in comparison with the low-risk group. The function of the oxidative phosphorylation-related prognostic gene set was verified by GO and KEGG analysis. Furthermore, the link between oxidative phosphorylation-related genes and osteosarcoma immune infiltration was examined by GSEA analysis. CONCLUSIONS:In this study, a prognostic model that demonstrated good predictive performance was constructed. Additionally, this study highlighted a correlation between oxidative phosphorylation-related genes and immune infiltration.

Background: Placenta-associated 8 protein (PLAC8) has been documented to play a role in tumorigenesis and tumor progression in various malignancies. However, there is still limited understanding of its function in Osteosarcoma (OS). This study aimed to analyze the potential effects and understand the underlying molecular mechanism of PLAC8 in OS.Methods: The expression patterns of PLAC8 were investigated in OS cell lines and clinical tissue samples. The effects of PLAC8 on cell proliferation and movement were assessed by Cell Counting Kit-8 (CCK-8), colony formation, Transwell (R), and woundhealing assays. Additionally, qRT-PCR, Western blotting, and luciferase reporter assays were performed to examine the expression and explore the molecular mechanisms behind PLAC8. Finally, to further determine the effect of PLAC8 in vivo, tumorigenesis and metastasis assays were employed in a mouse xenograft tumor model.Results: The current study revealed that PLAC8 was significantly overexpressed in clinical OS samples (p < 0.01) and in indicated cell lines (p < 0.05). In vitro experiments uncovered that PLAC8 could enhance the proliferative and metastatic probability of OS (p < 0.05). In addition, PLAC8 knockdown attenuated OS tumorigenesis in vivo. Moreover, PLAC8 was positively associated with the levels of C-X-C motif chemokine ligand 5 (CXCL5) in osteosarcoma, and PLAC8 overexpression upregulated CXCL5 mRNA (p < 0.01) and protein (p < 0.05). Mechanistically, microRNA-363-3p (miR-363-3p), suppressed by PLAC8, could directly target CXCL5 mRNA, leading to a decrease in CXCL5. Functionally, rescue and blocking assays validated that PLAC8 could promote the growth and mobility of osteosarcoma cells by releasing the targeting of CXCL5 by miR-363-3p.Conclusions: In summary, the oncogenic role of PLAC8 contributed to the development of osteosarcoma by mediating the miR363-3p/CXCL5 axis. The finding may serve as a valuable reference for precise treatment and therapeutic development in osteosarcoma.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor response to all therapeutic modalities and dismal prognosis. The presence of tertiary lymphoid structures (TLSs) in various solid cancers is of crucial prognostic significance, highlighting the intricate interplay between the tumor microenvironment and immune cells aggregation. However, the extent to which TLSs and immune status affect PDAC prognosis remains incompletely understood. Here, we sought to unveil the unique properties of TLSs in PDAC by leveraging both single-cell and bulk transcriptomics, culminating in a risk model that predicts clinical outcomes. We used TLS scores based on a 12-gene (CCL2, CCL3, CCL4, CCL5, CCL8, CCL18, CCL19, CCL21, CXCL9, CXCL10, CXCL11, and CXCL13) and 9-gene (PTGDS, RBP5, EIF1AY, CETP, SKAP1, LAT, CCR6, CD1D, and CD79B) signature, respectively, and examined their distribution in cell clusters of single-cell data from PDAC samples. The markers involved in these clusters were selected to develop a prognostic model using The Cancer Genome Atlas Program database as the training cohort and Gene Expression Omnibus database as the validation cohort. Further, we compared the immune infiltration, drug sensitivity, and enriched and differentially expressed genes between the high- and low-risk groups in our model. Therefore, we established a risk model that has significant implications for the prognostic assessment of PADC patients with remarkable differences in immune infiltration and chemosensitivity between the low- and high-risk groups. This paradigm established by TLS-related cell marker genes provides a prognostic prediction and a panel of novel therapeutic targets for exploring potential immunotherapy. We established a computational model to serve as a prognostic indicator for pancreatic cancer patients using the signatures of TLSs before treatment initiation.