Calcaneal Lengthening after Tarsal Bone Fusion for Massive Calcaneus Defect Reconstruction.

OBJECTIVES: Calcaneus defect remains challenging with limited strategies for reconstruction. Current methods, including graft transplantation, substitution, and distraction osteogenesis, showed limited advantages with certain shortcomings. Current calcaneus lengthening for partial calcaneus loss reconstruction requires bone loss of less than 35%. We introduced our combination of tarsal bone fusion and gradual lengthening method in treating massive calcaneus loss. METHODS: From January 2015 to December 2021, tarsal bone fusion and calcaneus gradual lengthening were performed in six patients with unilateral massive traumatic loss of the calcaneal tuberosity. A retrospective study was held to evaluate the outcomes of this novel technique. Clinical outcomes were assessed based on the American Orthopedic Foot and Ankle Score (AOFAS). Radiological data were assessed, which included tibio-calcaneal angle (TCA), calcaneal interface angle (CIA), metatarsal declination angle (MDA), angle of longitudinal arch (ALA), and the amount of calcaneus axial lengthening (CAL). RESULTS: The mean calcaneal axial lengthening was 43.8 ± 3.1 mm (range, 39-49.5 mm), and the mean proportion of the lengthened calcaneus was 47.8% ± 3.7% (range, 42.8-55.3%). The mean external fixation time was 104.8 ± 67.5 days (range, 69 to 242 days), and the mean external fixation index was 2.4 ± 1.6 days/cm. All patients stuck to the postoperative follow-up plan with an average follow-up time (FT) of 35.0 ± 6.7 months (range, 26-40 months). Deformities of the injured limbs were all corrected according to radiography. Based on the AOFAS, three excellent and three good results were achieved. CONCLUSION: The Ilizarov technique remains an option for calcaneus reconstruction with a great amount of loss once combined with tarsal bone fusion. The function of the injured foot and ankle can be satisfactorily restored using these techniques in our study. Apart from calcaneus elongation, tarsal bone fusion is somehow necessary to reinforce the proximal segment of the distracted calcaneus for creating a larger distraction callus, correcting concomitant foot deformities, and enhancing hindfoot stability. It is necessary to choose flexibly when tarsal bones should be fused.

Disrupting YAP1-mediated glutamine metabolism induces synthetic lethality alongside ODC1 inhibition in osteosarcoma.

PURPOSE: Osteosarcoma, a highly malignant primary bone tumor primarily affecting adolescents, frequently develops resistance to initial chemotherapy, leading to metastasis and limited treatment options. Our study aims to uncover novel therapeutic targets for metastatic and recurrent osteosarcoma. METHODS: In this study, we proved the potential of modulating the YAP1-regulated glutamine metabolic pathway to augment the response of OS to DFMO. We initially employed single-cell transcriptomic data to gauge the activation level of polyamine metabolism in MTAP-deleted OS patients. This was further substantiated by transcriptome sequencing data from recurrent and non-recurrent patient tissues, confirming the activation of polyamine metabolism in progressive OS. Through high-throughput drug screening, we pinpointed CIL56, a YAP1 inhibitor, as a promising candidate for a combined therapeutic strategy with DFMO. In vivo, we utilized PDX and CDX models to validate the therapeutic efficacy of this drug combination. In vitro, we conducted western blot analysis, qPCR analysis, immunofluorescence staining, and PuMA experiments to monitor alterations in molecular expression, distribution, and tumor metastasis capability. We employed CCK-8 and colony formation assays to assess the proliferative capacity of cells in the experimental group. We used flow cytometry and reactive oxygen probes to observe changes in ROS and glutamine metabolism within the cells. Finally, we applied RNA-seq in tandem with metabolomics to identify metabolic alterations in OS cells treated with a DFMO and CIL56 combination. This enabled us to intervene and validate the role of the YAP1-mediated glutamine metabolic pathway in DFMO resistance. RESULTS: Through single-cell RNA-seq data analysis, we pinpointed a subset of late-stage OS cells with significantly upregulated polyamine metabolism. This upregulation was further substantiated by transcriptomic profiling of recurrent and non-recurrent OS tissues. High-throughput drug screening revealed a promising combination strategy involving DFMO and CIL56. DFMO treatment curbs the phosphorylation of YAP1 protein in OS cells, promoting nuclear entry and initiating the YAP1-mediated glutamine metabolic pathway. This reduces intracellular ROS levels, countering DFMO's anticancer effect. The therapeutic efficacy of DFMO can be amplified both in vivo and in vitro by combining it with the YAP1 inhibitor CIL56 or the glutaminase inhibitor CB-839. This underscores the significant potential of targeting the YAP1-mediated glutamine metabolic pathway to enhance efficacy of DFMO. CONCLUSION: Our findings elucidate YAP1-mediated glutamine metabolism as a crucial bypass mechanism against DFMO, following the inhibition of polyamine metabolism. Our study provides valuable insights into the potential role of DFMO in an "One-two Punch" therapy of metastatic and recurrent osteosarcoma.

Biochemical hallmarks-targeting antineoplastic nanotherapeutics.

Tumor microenvironments (TMEs) have received increasing attention in recent years as they play pivotal roles in tumorigenesis, progression, metastases, and resistance to the traditional modalities of cancer therapy like chemotherapy. With the rapid development of nanotechnology, effective antineoplastic nanotherapeutics targeting the aberrant hallmarks of TMEs have been proposed. The appropriate design and fabrication endow nanomedicines with the abilities for active targeting, TMEs-responsiveness, and optimization of physicochemical properties of tumors, thereby overcoming transport barriers and significantly improving antineoplastic therapeutic benefits. This review begins with the origins and characteristics of TMEs and discusses the latest strategies for modulating the TMEs by focusing on the regulation of biochemical microenvironments, such as tumor acidosis, hypoxia, and dysregulated metabolism. Finally, this review summarizes the challenges in the development of smart anti-cancer nanotherapeutics for TME modulation and examines the promising strategies for combination therapies with traditional treatments for further clinical translation.

Magnetic-driven hydrogel microrobots for promoting osteosarcoma chemo-therapy with synthetic lethality strategy.

The advancements in the field of micro-robots for drug delivery systems have garnered considerable attention. In contrast to traditional drug delivery systems, which are dependent on blood circulation to reach their target, these engineered micro/nano robots possess the unique ability to navigate autonomously, thereby enabling the delivery of drugs to otherwise inaccessible regions. Precise drug delivery systems can improve the effectiveness and safety of synthetic lethality strategies, which are used for targeted therapy of solid tumors. MYC-overexpressing tumors show sensitivity to CDK1 inhibition. This study delves into the potential of Ro-3306 loaded magnetic-driven hydrogel micro-robots in the treatment of MYC-dependent osteosarcoma. Ro-3306, a specific inhibitor of CDK1, has been demonstrated to suppress tumor growth across various types of cancer. We have designed and fabricated this micro-robot, capable of delivering Ro-3306 precisely to tumor cells under the influence of a magnetic field, and evaluated its chemosensitizing effects, thereby augmenting the therapeutic efficacy and introducing a novel possibility for osteosarcoma treatment. The clinical translation of this method necessitates further investigation and validation. In summary, the Ro-3306-loaded magnetic-driven hydrogel micro-robots present a novel strategy for enhancing the chemosensitivity of MYC-dependent osteosarcoma, paving the way for new possibilities in future clinical applications.

Alternative splicing and related RNA binding proteins in human health and disease.

Alternative splicing (AS) serves as a pivotal mechanism in transcriptional regulation, engendering transcript diversity, and modifications in protein structure and functionality. Across varying tissues, developmental stages, or under specific conditions, AS gives rise to distinct splice isoforms. This implies that these isoforms possess unique temporal and spatial roles, thereby associating AS with standard biological activities and diseases. Among these, AS-related RNA-binding proteins (RBPs) play an instrumental role in regulating alternative splicing events. Under physiological conditions, the diversity of proteins mediated by AS influences the structure, function, interaction, and localization of proteins, thereby participating in the differentiation and development of an array of tissues and organs. Under pathological conditions, alterations in AS are linked with various diseases, particularly cancer. These changes can lead to modifications in gene splicing patterns, culminating in changes or loss of protein functionality. For instance, in cancer, abnormalities in AS and RBPs may result in aberrant expression of cancer-associated genes, thereby promoting the onset and progression of tumors. AS and RBPs are also associated with numerous neurodegenerative diseases and autoimmune diseases. Consequently, the study of AS across different tissues holds significant value. This review provides a detailed account of the recent advancements in the study of alternative splicing and AS-related RNA-binding proteins in tissue development and diseases, which aids in deepening the understanding of gene expression complexity and offers new insights and methodologies for precision medicine.

Telocinobufagin inhibits osteosarcoma growth and metastasis by inhibiting the JAK2/STAT3 signaling pathway.

Osteosarcoma is the most common primary bone malignancy in children and adolescents; it exhibits rapid growth and a high metastatic potential and may thus lead to relatively high mortality. The JAK2/STAT3 signaling pathway, which plays a critical role in the occurrence and development of osteosarcoma, is a potential target for the treatment of osteosarcoma. Here, we identified the natural product telocinobufagin (TCB), which is a component isolated from toad cake, as a potent candidate with anti-osteosarcoma effects. TCB inhibited osteosarcoma cell growth, migration, invasion and induced cancer cell apoptosis. Mechanistically, TCB specifically inhibited the JAK2/STAT3 signaling pathway. More importantly, TCB significantly suppressed tumor growth and metastasis in an osteosarcoma xenograft animal model. Moreover, TCB also showed strong inhibitory effects in other cancer types, such as lung cancer, liver cancer, colon cancer, breast cancer and gastric cancer. Hence, our study reveals TCB as a potent anti-osteosarcoma therapeutic agent that inhibits the JAK2/STAT3 signaling pathway.

Multi-omics analysis identifies osteosarcoma subtypes with distinct prognosis indicating stratified treatment.

Osteosarcoma (OS) is a primary malignant bone tumor that most commonly affects children, adolescents, and young adults. Here, we comprehensively analyze genomic, epigenomic and transcriptomic data from 121 OS patients. Somatic mutations are diverse within the cohort, and only TP53 is significantly mutated. Through unsupervised integrative clustering of the multi-omics data, we classify OS into four subtypes with distinct molecular features and clinical prognosis: (1) Immune activated (S-IA), (2) Immune suppressed (S-IS), (3) Homologous recombination deficiency dominant (S-HRD), and (4) MYC driven (S-MD). MYC amplification with HR proficiency tumors is identified with a high oxidative phosphorylation signature resulting in resistance to neoadjuvant chemotherapy. Potential therapeutic targets are identified for each subtype, including platinum-based chemotherapy, immune checkpoint inhibitors, anti-VEGFR, anti-MYC and PARPi-based synthetic lethal strategies. Our comprehensive integrated characterization provides a valuable resource that deepens our understanding of the disease, and may guide future clinical strategies for the precision treatment of OS.

O-arm-guided percutaneous microwave ablation and cementoplasty for the treatment of pelvic acetabulum bone metastasis.

Objective: This study aims to evaluate the indications, safety, and efficacy of microwave ablation combined with cementoplasty under O-arm navigation for the treatment of painful pelvic bone metastasis. Methods: We retrospectively collected data from 25 patients with acetabulum bone metastasis who underwent microwave ablation combined with cementoplasty. All patients underwent percutaneous microwave ablation combined with cementoplasty under O-arm navigation. The postoperative follow-up included evaluations of pain, quality of life, function, the incidence of bone cement leakage, and the presence of perioperative complications. Pain and quality of life were evaluated using the visual analog scale (VAS) and the QLQ-BM22 quality of life questionnaire for patients with bone metastases, respectively. The functional scores were calculated using the MSTS93 scoring system of the Bone and Soft Tissue Oncology Society. Results: There were 10 males and 15 females with an average age of 52.5 ± 6.5 years, all 25 patients received percutaneous procedures, and no technical failure occurred. Major complications, including pulmonary embolism, vascular or nervous injury, hip joint cement leakage, and infection, were not observed in the current study. Pain regression was achieved in 24 of 25 patients. The mean VAS scores significantly decreased to 3.4 ± 1.0, 2.5 ± 1.2, and 1.2 ± 0.6 points at 1 week, 1 month, and 3 months after the procedure, respectively, compared with 7.0 points before the procedure (P < .05). The mean QLQ-BM22 score significantly decreased to 36.2 ± 4.9, 30 ± 5.6, and 25.4 ± 2.3 points at 1 week, 1 month, and 3 months after the procedure, respectively, compared with 55.8 points before the procedure (P < .05). The preoperative Musculoskeletal tumour society (MSTS) functional score of 25 patients was 18.5 ± 5.3 points, and MSTS score was 20.0 ± 3.0, 21.4 ± 4.9, and 22.8 ± 2.3 at 1 week, 1 month, and 3 months after the procedure, respectively (P < .05). The average bone cement injection volume was 8.8 ± 4.6 ml. Conclusion: The use of O-arm-guided percutaneous microwave ablation combined with cementoplasty for the treatment of pelvic metastases could quickly and significantly alleviate local pain, prevent pathological fracture, and improve the quality of life of patients with reduced complications.

Detection and surveillance of circulating tumor cells in osteosarcoma for predicting therapy response and prognosis.

OBJECTIVE: Osteosarcoma (OS) is an aggressive, highly metastatic, relatively drug-resistant bone tumor with poor long-term survival rates. The presence and persistence of circulating tumor cells (CTCs) in the peripheral blood are believed to be associated with treatment inefficiency and distant metastases. A blood-based CTC test is thus greatly needed for monitoring disease progression and predicting clinical outcomes. However, traditional methods cannot detect CTCs from tumors of mesenchymal origin such as OS, and research on CTC detection in mesenchymal tumors has been hindered for years. METHODS: In this study, we developed a CTC test based on hexokinase 2, a metabolic function-associated marker, for the detection and surveillance of OS CTCs, and subsequently explored its clinical value. Twelve patients with OS were enrolled as the training cohort for serial CTC tests. Dynamic CTC counting, in combination with therapy evaluation and post-treatment follow-up, was used to establish a model for predicting post-chemotherapy evaluation and disease-free survival, and the model was further validated with a cohort of 8 patients with OS. RESULTS: Two dynamic CTC number patterns were identified, and the resulting predictive model exhibited 92% consistency with the clinical outcomes. This model suggested that a single CTC test has similar predictive power to serial CTC analysis. In the validation cohort, the single CTC test exhibited 100% and 87.5% consistency with therapy response and disease-free survival, respectively. CONCLUSIONS: Our non-invasive test for detection and surveillance of CTCs enables accurate prediction of therapy efficiency and prognosis, and may be clinically valuable for avoiding inefficient therapy and prolonging survival.

Magnetic-Driven Hydrogel Microrobots Selectively Enhance Synthetic Lethality in MTAP-Deleted Osteosarcoma.

Background: Drugs based on synthetic lethality have advantages such as inhibiting tumor growth and affecting normal tissue in vivo. However, specific targets for osteosarcoma have not been acknowledged yet. In this study, a non-targeted but controllable drug delivery system has been applied to selectively enhance synthetic lethality in osteosarcoma in vitro, using the magnetic-driven hydrogel microrobots. Methods: In this study, EPZ015666, a PRMT5 inhibitor, was selected as the synthetic lethality drug. Then, the drug was carried by hydrogel microrobots containing Fe3O4. Morphological characteristics of the microrobots were detected using electron microscopy. In vitro drug effect was detected by the CCK-8 assay kit, Western blotting, etc. Swimming of microrobots was observed by a timing microscope. Selective inhibition was verified by cultured tumors in an increasing magnetic field. Results: Genomic mutation of MTAP deletion occurred commonly in pan-cancer in the TCGA database (nearly 10.00%) and in osteosarcoma in the TARGET database (23.86%). HOS and its derivatives, 143B and HOS/MNNG, were detected by MTAP deletion according to the CCLE database and RT-PCR. EPZ015666, the PRMT5 inhibitor, could reduce the SDMA modification and inhibition of tumor growth of 143B and HOS/MNNG. The hydrogel microrobot drug delivery system was synthesized, and the drug was stained by rhodamine. The microrobots were powered actively by a magnetic field. A simulation of the selected inhibition of microrobots was performed and lower cell viability of tumor cells was detected by adding a high dose of microrobots. Conclusion: Our magnetic-driven drug delivery system could carry synthetic lethality drugs. Meanwhile, the selective inhibition of this system could be easily controlled by programming the strength of the magnetic field.

PLCD1-Induced DNA Damage Inhibits the Tumor Growth via Downregulating CDKs in Chondrosarcoma.

Purpose: Typical genes for the treatment and diagnosis of high-grade chondrosarcoma are still in need. Our study aimed to explore the PLCD1 function in chondrosarcoma for further treatment. Materials and Methods: Our study collected the information of 49 patients in our department. The PLCD1 expression in our cohort was detected and was compared with the TCGA database. PLCD1 knockdown and overexpression cell lines were established stably. Cell viability assay and colony formation assay were performed for cell proliferation. Flow cytometry analysis was performed for cell cycle and apoptosis. Western blotting was performed for PLCD1-related protein expression. Animal xenografts were established to verify the effect of PLCD1 in high-grade chondrosarcoma. Results: Compared with the TCGA database, the relation between PLCD1 expression and the malignancy of chondrosarcoma was demonstrated. A lower PLCD1 expression was detected mainly in high-grade chondrosarcoma. PLCD1 overexpression in high-grade chondrosarcoma suppressed CDKs/cyclins and induced DNA damage causing cell cycle blocking and apoptosis. Antitumor effect of PLCD1 overexpression was verified in vivo. Conclusion: Lower PLCD1 was expressed in high-grade chondrosarcoma. Overexpressed PLCD1-induced DNA damage caused cell cycle blocking and apoptosis in vitro and in vivo. PLCD1 could be a novel target in high-grade chondrosarcoma for further drug development.

THz Filters Made by Laser Ablation of Stainless Steel and Kapton Film.

THz band-pass filters were fabricated by femtosecond-laser ablation of 25-µm-thick micro-foils of stainless steel and Kapton film, which were subsequently metal coated with a ∼70 nm film, closely matching the skin depth at the used THz spectral window. Their spectral performance was tested in transmission and reflection modes at the Australian Synchrotron's THz beamline. A 25-µm-thick Kapton film performed as a Fabry-Pérot etalon with a free spectral range (FSR) of 119 cm-1, high finesse Fc≈17, and was tuneable over ∼10µm (at ∼5 THz band) with ß=30∘ tilt. The structure of the THz beam focal region as extracted by the first mirror (slit) showed a complex dependence of polarisation, wavelength and position across the beam. This is important for polarisation-sensitive measurements (in both transmission and reflection) and requires normalisation at each orientation of linear polarisation.

Do reverse total shoulder replacements have better clinical and functional outcomes than hemiarthroplasty for patients undergoing proximal humeral tumor resection using devitalized autograft composite reconstruction: a case-control study.

OBJECTIVE: To compare the efficacy and prognosis of reverse total shoulder arthroplasty (rTSA) with shoulder hemiarthroplasty (SHA) using devitalized autograft or allograft composite reconstruction after proximal humeral tumor resection. METHODS: We retrospectively reviewed patients who underwent SHA (32) and rTSA (20) for tumor resections of the proximal humerus from January 2014 to July 2020. The clinical results included duration of the operation, intraoperative blood loss, bone union, visual analog scale (VAS) score, shoulder range of motion (ROM), American Shoulder and Elbow Surgeons (ASES) shoulder score, recurrence, and overall survival. RESULTS: Fifty-two patients were followed up for a mean of 30 months. Thirty-two patients were SHA with allograft-prosthetic composite (APC) reconstructions, while other 20 were rTSA with devitalized autograft-prosthetic composite reconstructions. At the end of the follow-up, 2 recurrence, 3 postoperative infections, and 4 subluxations occurred among the SHA patients. Two patients in the rTSA group had postoperative anterior dislocation and underwent revision surgery with surgical mesh, and 2 (2/20) had grade II scapular notching. The mean VAS score of the shoulder was 1.5 ± 0.8 in the rTSA group and 2.3 ± 1.2 in the SHA group (p < 0.05). The mean active forward flexion of the shoulder joint was 50.6 ± 6.0 in the SHA group and 100 ± 7.6 in the rTSA group (p < 0.05). The ASES shoulder score was 78 ± 3.0 in the rTSA group and 52 ± 5.6 in the SHA group (p < 0.05). The overall 3-year survival rate of all patients was 60.0%, and patients in the rTSA group showed better survival in terms of the mean 3-year OS than patients in the SHA group (p = 0.04). CONCLUSION: rTSA with devitalized autograft-prosthetic composite can offer a reasonable reconstruction of the shoulder joint after Malawer type I tumor resection. Compared with patients who underwent SHA, patients who underwent rTSA present good outcomes, a better range of motion, better bone union, and no increase in instability rate in the mid-term.

Bromodomain Inhibition Attenuates the Progression and Sensitizes the Chemosensitivity of Osteosarcoma by Repressing GP130/STAT3 Signaling.

Osteosarcoma is the most common primary malignant bone tumor, and there are few ideal clinically available drugs. The bromodomain and extraterminal domain (BET) protein is an emerging target for aggressive cancer, but therapies targeting the BET in osteosarcoma have been unsuccessful in clinical trials to date, and further exploration of specific BET inhibitors is of great significance. In our study, we demonstrated that NHWD-870, a potent BET inhibitor in a phase I clinical trial, significantly inhibited tumor proliferation and promoted cell apoptosis by reversing the oncogenic signature in osteosarcoma. More importantly, we identified NHWD-870 impeded binding of BRD4 to the promoter of GP130 leading to diminished activation of JAK/STAT3 signaling pathway. Furthermore, GP130 knockdown significantly sensitizes the chemosensitivity in vitro. In OS cell-derived xenografts, NHWD-870 effectively inhibited the growth of osteosarcoma. Beyond that, NHWD-870 effectively inhibited the differentiation and maturation of precursor osteoclasts in vitro and attenuated osteoclast-mediated bone loss in vivo. Finally, we confirmed the efficacy of synthetic lethal effects of NHWD-870 and cisplatin in antagonizing osteosarcoma in a preclinical PDX model. Taken together, these findings demonstrate that NHWD-870, as an effective BET inhibitor, may be a potential candidate for osteosarcoma intervention linked to its STAT3 signaling inhibitory activity. In addition, NHWD-870 appears to be a promising therapeutic strategy for bone-associated tumors, as it interferes with the vicious cycle of tumor progression and bone destruction.

H3.3 K36M Mutation as a Clinical Diagnosis Method of Suspected Chondroblastoma Cases.

OBJECTIVE: Whether H3.3 K36M mutation (H3K36M) could be an approach if the diagnosis of chondroblastoma (CB) patients was indistinct and it was suspected to be unclear clinically. METHODS: We reviewed and compared our clinical experiences of CB cases and some suspected cases, which were not diagnosed distinctly, between 2013 to 2019. A total of 15 male and four female cases included in this study were seperated into two groups, CB group and suspected case (SC) group. The CB group included 13 men and 3 women, with an age range from 9 to 54 (mean age, 22 years old). The SC group included two men and one woman, with the age range from 13 to 25 (mean age, 19 years old). In both groups the patients had been followed-up until December 2019 and none of the patients had prior treatment history. We evaluated the clinical complaints, radiological features, and clinical-histological features of the cases and performed an immunohistochemical (IHC) study to detect whether the H3K36M expression of cases was different, consistent with a gene-mutation analysis. RESULTS: In both groups, the radiologic features of both groups appeared as round low-density shadow with a clear edge, pathologic features showed diffuse proliferation of neoplastic cells with multinuclear giant cells. The radiological tumor size of CB group and SC group showed little difference, which was about 29.0*21.6 mm. Clinical-immunohistochemical features of both groups showed chondroid matrix inside with naïve tumor cells, multinucleated giant cells, and ground substance cells. Most of them showed chondro-related antibody positive (12 cases) but some of them showed S-100 negative (four cases). The clear difference of both groups was the result of H3K36M IHC study and gene analysis. In our cases, the CB group showed diffuse H3K36M positive and the SC group showed negative. The gene mutation analysis revealed that H3K36M-positive CB patients had K36M mutation, which were not found in the SC group. Sanger sequencing showed an A > T substitution at codon 36 of histone H3F3B. No other types of histone H3 mutation was detected in the CB group. Particularly, one of the suspected cases showed a G34W mutation was confirmed to be a giant cell tumor of bone (GCTB). CONCLUSIONS: Our study showed H3K36M immunohistochemistry and gene mutation analysis were specific clinical diagnostic tools to distinguish suspected CB from other giant cell-rich or cartilage matrix-diffuse bone tumors. The clinical-radiological and histomorphological features of patients gave suggestions on whether the H3K36M IHC and gene analysis should be required.