Efficacy and Safety of Fruquintinib-Based Treatment in Patients with Refractory Bone and Soft Tissue Sarcoma after Developing Resistance to Several TKIs: A Multicenter Retrospective Study.

OBJECTIVE: Multitargeted tyrosine kinase inhibitors (TKIs) have been approved as second-line therapy in refractory sarcoma, prolonging progression-free survival (PFS) but with short-lived duration of disease control. Fruquintinib is a TKI that specifically inhibits vascular endothelial growth factor receptor-1,2,3 with no metabolism by liver enzymes. In this retrospective study, we assessed the efficacy and safety of fruquintinib-based treatment in patients with refractory sarcoma after developing several lines of TKI resistance. METHODS: We retrospectively analyzed the clinical data of patients with refractory sarcoma after they had developed several lines of resistance to TKIs and who received fruquintinib-based treatment from November 2021 to August 2023. The primary endpoint was the progression-free survival rate at 4 months (4m-PFSR). Secondary endpoints were the median PFS, overall survival (OS), objective response rate, disease control rate, and adverse effects (AEs). PFS and OS were estimated using the Kaplan-Meier method. A log-rank test was used to compare survival curves between different clinical and pathological factors. Cox proportional hazards analysis was performed to identify PFS-related prognostic factors. RESULTS: We included 124 patients: 56 (45.2%) with osteosarcoma, 28 (22.6%) with Ewing sarcoma, seven (5.6%) with chondrosarcoma, and 33 (26.6%) with soft tissue sarcomas (STS). Only 18 (14.5%) patients received monotherapy with fruquintinib. With a median follow-up time of 6.8 (interquartile range [IQR], 4.6-9.4) months, 22 (17.7%) patients had partial response and 78 (62.9%) had stable disease. The 4m-PFSR was 58.4% (95% confidence interval [CI], 49.6%-67.1%). The median PFS and OS were 4.4 (95% CI, 3.9-5.0) months and 11.4 (95% CI, 10.3-12.5) months. In multivariate analysis, a high hazard ratio for progression was associated with target lesions located outside the lung and bone with 1.79 (95% CI, 1.10-2.93; p = 0.020). Eighty-eight AEs were recorded in 47 (37.9%) patients; the most common were pneumothorax (18/124, 14.5%), diarrhea (8/124, 6.5%), oral mucositis (7/124, 5.6%), and thrombocytopenia (7/124, 5.6%). CONCLUSIONS: Fruquintinib may be a potential option for patients with refractory sarcoma after developing several lines of TKI resistance, with a satisfactory efficacy and safety profile in combination therapy. However, the degree of contribution of fruquintinib to results is unclear when combined with other effective substances. Additional prospective trials of fruquintinib should be conducted, especially involving different pathological types and combination regimens.

Novel positioning guiders accurately assist in situ acetabular reconstruction for patients undergoing pelvic bone tumor resection.

PURPOSE: Acetabular reconstruction in situ after extensive pelvic resection is technically challenging. The aim of this study was to investigate the feasibility of positioning guiders for acetabular reconstruction following pelvic tumor resection and the clinical benefit brought by the approach. METHODS: The study included patients who underwent acetabular reconstruction following periacetabular tumor resection using a modular hemipelvic prosthesis. In the guider-assisted group (n = 14), guiders were designed and applied to assist acetabular reconstruction. In the traditional operation group (n = 18), the patients underwent the same surgery but without the guiders. The displacement of the hip rotation center before and after surgery was calculated. The complications and the Musculoskeletal Tumor Society-93 scores were documented. RESULTS: The overall displacement of the hip rotation center was significantly reduced in the guider-assisted group compared with the traditional operation group (13.83 ± 4.06 vs. 22.95 ± 9.18 mm in P = 0.000, 95%CI 3.90-12.96), especially in the anteroposterior axis (3.77 ± 3.03 versus 13.51 ± 9.43 mm in P = 0.000, 95%CI 3.45-13.09). Guider-assisted acetabular reconstruction reduced the risk of prosthesis dislocation compared with the traditional operation (dislocation risks: 1/14, 7.1% vs. 4/18, 22.2%). CONCLUSION: Positioning guiders can effectively and conveniently help place the modular hemipelvic prosthesis at the native position, which might potentially reduce the risk of prosthesis dislocation. LEVEL OF EVIDENCE: Therapeutic level III.

Peripheral Soluble Immune Checkpoint-Related Proteins Were Associated with Survival and Treatment Efficacy of Osteosarcoma Patients, a Cohort Study.

BACKGROUND: The immune checkpoint blockade remains obscure in osteosarcoma (OS). We aim to explore the clinical significance of soluble immune checkpoint (ICK)-related proteins in OS. METHODS: We profiled 14 soluble ICK-related proteins (BTLA, GITR, HVEM, IDO, LAG-3, PD-1, PD-L1, PD-L2, TIM-3, CD28, CD80, CD137, CD27, and CTLA-4) in the plasma of 76 OS patients and matched controls. We evaluated the associations between the biomarkers and the risk of OS using unconditional multivariate logistic regression. The multivariate Cox model was utilized to develop the prediction model of OS. Immune subtypes were established from the identified biomarkers. Transcriptional data from GEO were analyzed to elucidate potential mechanisms. RESULTS: We found that sTIM3, sCD137, sIDO, and sCTLA4 were significantly correlated with OS risk (all p < 0.05). sBTLA, sPDL2, and sCD27 were significantly associated with the risk of lung metastasis, whereas sBTLA and sTIM3 were associated with the risk of disease progression. We also established an immune subtype based on sBTLA, sPD1, sTIM3, and sPDL2. Patients in the sICK-type2 subtype had significantly decreased progression-free survival (PFS) and lung metastasis-free survival (LMFS) than those in the sICK-type1 subtype (log-rank p = 2.8 × 10-2, 1.7 × 10-2, respectively). Interestingly, we found that the trend of LMFS and PFS in the subtypes of corresponding ICK genes' expression was opposite to the results in the blood (log-rank p = 2.6 × 10-4, 9.5 × 10-4, respectively). CONCLUSION: Four soluble ICK-related proteins were associated with the survival of OS patients. Soluble ICK-related proteins could be promising biomarkers for the outcomes and immunotherapy of OS patients, though more research is warranted.

Effect of radiotherapy on local control and overall survival in spinal metastasis of non-small-cell lung cancer after surgery and systemic therapy.

Aims: Radiotherapy is a well-known local treatment for spinal metastases. However, in the presence of postoperative systemic therapy, the efficacy of radiotherapy on local control (LC) and overall survival (OS) in patients with spinal metastases remains unknown. This study aimed to evaluate the clinical outcomes of post-surgical radiotherapy for spinal metastatic non-small-cell lung cancer (NSCLC) patients, and to identify factors correlated with LC and OS. Methods: A retrospective, single-centre review was conducted of patients with spinal metastases from NSCLC who underwent surgery followed by systemic therapy at our institution from January 2018 to September 2022. Kaplan-Meier analysis and log-rank tests were used to compare the LC and OS between groups. Associated factors for LC and OS were assessed using Cox proportional hazards regression analysis. Results: Overall, 123 patients with 127 spinal metastases from NSCLC who underwent decompression surgery followed by postoperative systemic therapy were included. A total of 43 lesions were treated with stereotactic body radiotherapy (SBRT) after surgery and 84 lesions were not. Survival rate at one, two, and three years was 83.4%, 58.9%, and 48.2%, respectively, and LC rate was 87.8%, 78.8%, and 78.8%, respectively. Histological type was the only significant associated factor for both LC (p = 0.007) and OS (p < 0.001). Treatment with targeted therapy was significantly associated with longer survival (p = 0.039). The risk factors associated with worse survival were abnormal laboratory data (p = 0.021), lesions located in the thoracic spine (p = 0.047), and lumbar spine (p = 0.044). This study also revealed that postoperative radiotherapy had little effect in improving OS or LC. Conclusion: Tumour histological type was significantly associated with the prognosis in spinal NSCLC metastasis patients. In the presence of post-surgical systemic therapy, radiotherapy appeared to be less effective in improving LC, OS, or quality of life in spinal NSCLC metastasis patients.

Comparison of Open Surgery Versus Minimally Invasive Surgery in Nonsevere Adult Degenerative Scoliosis: A Systematic Review and Meta-Analysis.

STUDY DESIGN: A systematic review and meta-analysis. OBJECTIVE: This study aimed to evaluate the clinical efficacy of minimally invasive surgery (MIS) and open surgery in correcting ADS. SUMMARY OF BACKGROUND DATA: Adult degenerative scoliosis (ADS) is a scoliosis secondary to degenerative changes in the intervertebral discs and facet joints in adults. Severe low back pain, radicular pain, and intermittent claudication are often present and require surgical treatment. METHODS: PubMed, Embase, The Cochrane Library, China National Knowledge Infrastructure (CNKI) Database, Wanfang Data, Weipu Database, and China Biomedical Document Service System (CBM) were systematically searched for studies that focused on the clinical efficacy of minimally invasive surgery and open surgery to correct ADS. RESULTS: This meta-analysis included 11 studies, involving 1527 patients (581 in the MIS group and 946 in the open surgery group). Regarding surgery and outcome indicators, the operative time in the open surgery group was shorter, the MIS group had less intraoperative blood loss, shorter hospitalization time, and lower incidence of serious postoperative complications. In terms of imaging parameters, although there was no significant difference in Cobb angle improvement and sagittal balance, the open surgery group exhibited better lumbar lordosis improvement and pelvic tilt improvement. In terms of clinical scores, including changes in the ODI index and VAS scores for low back and leg pain, similar improvements were appreciated across both groups. CONCLUSIONS: In mild to moderate ADS, we found that the advantages of open surgery include greater improvement in lumbar lordosis and pelvic tilt angle and shorter operative time. The advantages of minimally invasive surgery are less intraoperative blood loss, shorter hospital stay, and fewer serious postoperative complications. There is no significant difference between the 2 surgical methods in terms of Cobb angle, clinical pain, and sagittal vertical axis improvement.

ZIF-8-Encapsulated Pexidartinib Delivery via Targeted Peptide-Modified M1 Macrophages Attenuates MDSC-Mediated Immunosuppression in Osteosarcoma.

Adoptive cellular therapy is a promising strategy for cancer treatment. However, the effectiveness of this therapy is limited by its intricate and immunosuppressive tumor microenvironment. In this study, a targeted therapeutic strategy for macrophage loading of drugs is presented to enhance anti-tumor efficacy of macrophages. K7M2-target peptide (KTP) is used to modify macrophages to enhance their affinity for tumors. Pexidartinib-loaded ZIF-8 nanoparticles (P@ZIF-8) are loaded into macrophages to synergistically alleviate the immunosuppressive tumor microenvironment synergistically. Thus, the M1 macrophages decorated with KTP carried P@ZIF-8 and are named P@ZIF/M1-KTP. The tumor volumes in the P@ZIF/M1-KTP group are significantly smaller than those in the other groups, indicating that P@ZIF/M1-KTP exhibited enhanced anti-tumor efficacy. Mechanistically, an increased ratio of CD4+ T cells and a decreased ratio of MDSCs in the tumor tissues after treatment with P@ZIF/M1-KTP indicated that it can alleviate the immunosuppressive tumor microenvironment. RNA-seq further confirms the enhanced immune cell function. Consequently, P@ZIF/M1-KTP has great potential as a novel adoptive cellular therapeutic strategy for tumors.

The chromatin remodeling factor Arid1a cooperates with Jun/Fos to promote osteoclastogenesis by epigenetically upregulating Siglec15 expression.

Osteoporosis is characterized by an imbalance between osteoclast-mediated bone resorption and osteoblast-related bone formation, particularly increased osteoclastogenesis. However, the mechanisms by which epigenetic factors regulate osteoclast precursor differentiation during osteoclastogenesis remain poorly understood. Here, we show that the specific knockout of the chromatin remodeling factor Arid1a in bone marrow-derived macrophages (BMDMs) results in increased bone mass. The loss of Arid1a in BMDM inhibits cell-cell fusion and maturation of osteoclast precursors, thereby suppressing osteoclast differentiation. Mechanistically, Arid1a increases the chromatin access in the gene promoter region of sialic acid-binding Ig-like lectin 15 (Siglec15) by transcription factor Jun/Fos, which results in the upregulation of Siglec15 and promotion of osteoclast differentiation. However, the loss of Arid1a reprograms the chromatin structure to restrict Siglec15 expression in osteoclast precursors, thereby inhibiting BMDM differentiation into mature osteoclasts. Deleting Arid1a after ovariectomy (a model for postmenopausal bone loss) alleviated bone loss and maintained bone mass. In summary, epigenetic reprogramming mediated by Arid1a loss suppresses osteoclast differentiation and may serve as a promising therapeutic strategy for treating bone loss diseases.

Osteoporosis is a common disease, usually diagnosed by decreased bone density and increased fragility. The people with osteoporosis has higher risk of fractures. Nearly one-third of the aged people will suffer from osteoporosis-related fractures and even lose their lives because of this. Therefore, there is an urgent need for early intervention and effective treatment options for osteoporosis in the aging population. Bone tissue is a highly dynamic tissue that undergoes continuous remodeling throughout an individual's entire life. The balance of remodeling depends on the bone formation mediated by osteoblasts and bone resorption by osteoclasts. When this balance is disrupted, osteoporosis occurs. Thus, the aim of our research is to explore the behind mechanism of this imbalance. Here, we demonstrate that the loss of Arid1a, a chromatin remodeler, leads to chromatin reprogramming that restricts access to promoters by transcription factors such as Jun/Fos, thereby suppressing osteoclast activation and bone resorption. Our findings offer insights into the epigenetic mechanisms underlying osteoporosis and suggest potential strategies for its prevention and treatment.

First-Line Anlotinib Treatment for Soft Tissue Sarcoma in Chemotherapy-Ineligible Patients: An Open-label, Single-arm, Phase 2 Clinical Trial.

PURPOSE: Standard treatment for patients with unresectable locally advanced or metastatic soft-tissue sarcoma (LA/M STS) is chemotherapy based on anthracyclines, but patient tolerance of chemotherapy is limited. The present trial (NCT03792542) investigated the use of anlotinib as first-line treatment for patients with advanced STS, in particular liposarcoma (LPS). PATIENTS AND METHODS: Eligible patients were previously untreated, pathologically confirmed, unresectable LA/M STS cases. Anlotinib was given orally at a dose of 12 mg once daily from day 1 to day 14 every 3 weeks until disease progression or intolerable adverse events (AEs) occurred. The primary endpoint was progression-free survival (PFS) and the secondary endpoints overall survival (OS), the objective response rate and the disease control rate (DCR). The safety profile was also evaluated. RESULTS: Forty patients were enrolled from April 2019 to Jun 2022 and are included in the intention-to-treat analysis. The median PFS was 6.83 months [95% confidence interval (CI): 4.17-8.71] and the median OS 27.40 months (95% CI: 16.43-not evaluable); 1 patient reached partial response and 26 attained stable disease, with a DCR of 67.5% (27/40). Median PFS and OS times for LPS patients were 8.71 and 16.23 months, respectively. Ten (25.0%) patients had treatment-related AEs ≥ grade 3, with in particular a higher incidence of hypertension (15.0%) and proteinuria (7.5%). CONCLUSIONS: The findings suggest a potential benefit in employing front-line anlotinib to treat patients with STS, who are not eligible for cytotoxic chemotherapy. Of note, the clinical outcomes for the LPS subgroup of patients were encouraging.

Multiple influence of immune cells in the bone metastatic cancer microenvironment on tumors.

Bone is a common organ for solid tumor metastasis. Malignant bone tumor becomes insensitive to systemic therapy after colonization, followed by poor prognosis and high relapse rate. Immune and bone cells in situ constitute a unique immune microenvironment, which plays a crucial role in the context of bone metastasis. This review firstly focuses on lymphatic cells in bone metastatic cancer, including their function in tumor dissemination, invasion, growth and possible cytotoxicity-induced eradication. Subsequently, we examine myeloid cells, namely macrophages, myeloid-derived suppressor cells, dendritic cells, and megakaryocytes, evaluating their interaction with cytotoxic T lymphocytes and contribution to bone metastasis. As important components of skeletal tissue, osteoclasts and osteoblasts derived from bone marrow stromal cells, engaging in 'vicious cycle' accelerate osteolytic bone metastasis. We also explain the concept tumor dormancy and investigate underlying role of immune microenvironment on it. Additionally, a thorough review of emerging treatments for bone metastatic malignancy in clinical research, especially immunotherapy, is presented, indicating current challenges and opportunities in research and development of bone metastasis therapies.

Investigating the synergy of Shikonin and Valproic acid in inducing apoptosis of osteosarcoma cells via ROS-mediated EGR1 expression.

BACKGROUND: Osteosarcoma is the most prevalent malignant bone tumour with a poor prognosis. Shikonin (SHK) is derived from the traditional Chinese medicine Lithospermum that has been extensively studied for its notable anti-tumour effects, including for osteosarcoma. However, its application has certain limitations. Valproic acid (VPA) is a histone deacetylase inhibitor (HDACI) that has recently been employed as an adjunctive therapeutic agent that allows chromatin to assume a more relaxed state, thereby enhancing anti-tumour efficacy. PURPOSE: This study was aimed to investigate the synergistic anti-tumour efficacy of SHK in combination with VPA and elucidate its underlying mechanism. METHODS/STUDY DESIGN: CCK-8 assays were utilized to calculate the combination index. Additional assays, including colony formation, acridine orange/ethidium bromide double fluorescent staining, and flow cytometry, were employed to evaluate the effects on osteosarcoma cells. Wound healing and transwell assays were utilized to assess cell mobility. RNA sequencing, PCR, and Western blot analyses were conducted to uncover the underlying mechanism. Rescue experiments were performed to validate the mechanism of apoptotic induction. The impact of SHK and VPA combination treatment on primary osteosarcoma cells was also assessed. Finally, in vivo experiments were conducted to validate its anti-tumour effects and mechanism. RESULTS: The combination of SHK and VPA synergistically inhibited the proliferation and migration of osteosarcoma cells in vitro and induced apoptosis in these cells. Through a comprehensive analysis involving RNA sequencing, PCR, Western blot, and rescue experiments, we have substantiated our hypothesis that the combination of SHK and VPA induced apoptosis via the ROS-EGR1-Bax axis. Importantly, our in vivo experiments corroborated these findings, demonstrating the potential of the SHK and VPA combination as a promising therapeutic approach for osteosarcoma. CONCLUSION: The combination of SHK and VPA exerted an anti-tumour effect by inducing apoptosis through the ROS-EGR1-Bax pathway. Repurposing the old drug VPA demonstrated its effectiveness as an adjunctive therapeutic agent for SHK, enhancing its anti-tumour efficacy and revealing its potential value. Furthermore, our study expanded the application of natural compounds in the anti-tumour field and overcame some of their limitations through combination therapy. Finally, we enhanced the understanding of the mechanistic pathways linking reactive oxygen species (ROS) accumulation and apoptosis in osteosarcoma cells. Additionally, we elucidated the role of EGR1 in osteosarcoma cells, offering novel strategies and concepts for the treatment of osteosarcoma.

A novel missense COL9A3 variant in a pedigree with multiple lumbar disc herniation.

Trp3 allele in COL9A3 gene has been widely studied in populations with intervertebral disc disease. We identified a novel pathogenic variant in COL9A3 gene in a pedigree with multiple lumbar disc herniation (LDH). The proband was a 14-year-old boy who developed LDH at the L4/5 and L5/S1 spinal segments. His father, paternal aunt and grandfather were diagnosed with LDH at an age of 35, 30 and 23, respectively. By applying whole exome sequencing, a heterozygous missense variant (c.1150C > T, p.Arg384Trp) in COL9A3 was identified. According to the ACMG guidelines, this variant is predicted to be pathogenic. In addition, prediction tools found COL9A3 protein of this variant a reduced stability, some changed charge properties, and an altered spatial conformation. Findings expanded the mutational spectrum of LDH and contributed to the understanding of COL9A3 in the pathogenesis of LDH.

Osteocyte mitochondria inhibit tumor development via STING-dependent antitumor immunity.

Bone is one of the most common sites of tumor metastases. During the last step of bone metastasis, cancer cells colonize and disrupt the bone matrix, which is maintained mainly by osteocytes, the most abundant cells in the bone microenvironment. However, the role of osteocytes in bone metastasis is still unclear. Here, we demonstrated that osteocytes transfer mitochondria to metastatic cancer cells and trigger the cGAS/STING-mediated antitumor response. Blocking the transfer of mitochondria by specifically knocking out mitochondrial Rho GTPase 1 (Rhot1) or mitochondrial mitofusin 2 (Mfn2) in osteocytes impaired tumor immunogenicity and consequently resulted in the progression of metastatic cancer toward the bone matrix. These findings reveal the protective role of osteocytes against cancer metastasis by transferring mitochondria to cancer cells and potentially offer a valuable therapeutic strategy for preventing bone metastasis.

An On-Demand Collaborative Innate-Adaptive Immune Response to Infection Treatment.

Deep tissue infection is a common clinical issue and therapeutic difficulty caused by the disruption of the host antibacterial immune function, resulting in treatment failure and infection relapse. Intracellular pathogens are refractory to elimination and can manipulate host cell biology even after appropriate treatment, resulting in a locoregional immunosuppressive state that leads to an inadequate response to conventional anti-infective therapies. Here, a novel antibacterial strategy involving autogenous immunity using a biomimetic nanoparticle (NP)-based regulating system is reported to induce in situ collaborative innate-adaptive immune responses. It is observed that a macrophage membrane coating facilitates NP enrichment at the infection site, followed by active NP accumulation in macrophages in a mannose-dependent manner. These NP-armed macrophages exhibit considerably improved innate capabilities, including more efficient intracellular ROS generation and pro-inflammatory factor secretion, M1 phenotype promotion, and effective eradication of invasive bacteria. Furthermore, the reprogrammed macrophages direct T cell activation at infectious sites, resulting in a robust adaptive antimicrobial immune response to ultimately achieve bacterial clearance and prevent infection relapse. Overall, these results provide a conceptual framework for a novel macrophage-based strategy for infection treatment via the regulation of autogenous immunity.

Surgical Options for Aggressive Vertebral Hemangiomas：A case series, literature review and treatment recommendations.

Purpose: We retrospectively study twenty-nine surgical cases of aggressive vertebral hemangiomas (AVHs) with neurological deficits and extradural compression to determine the optimal surgical treatment strategy for AVHs at a single institution. Methods: Patients with AVHs with neurological deficits who underwent partial tumor resection plus decompression with or without vertebroplasty (VP), and radiotherapy between 2010 and 2021 were included in this study. Clinical characteristics, surgical outcomes, and follow-up data of the patients were reviewed retrospectively. Results: Twenty-nine AVH cases with neurological deficits and spinal instability were included in this study and treated surgically. The mean operation time of patients with decompression surgery plus VP (Groupe A) was 215.9 (120-265 min), shorter than that of decompression surgery without VP (Group B) 240.2 (120-320 min). Intraoperative blood loss was 273.3 (100-550 mL) in group A and 635.3 (200-1600 mL) in group B. In addition, a significant reduction in blood loss was observed in group A compared to the group B (p=0.0001). All patients experienced immediate pain relief and improvement in their neurological symptoms. Neurological function was assessed by the Frankel score, ASIA score, and the visual analogue scale (VAS) pain score decreased from 7.4 (4-9) to 1.3 (0-3). Of twenty-nine patients in this study,  only 7% (2/29 patients) showed signs of recurrence. Conclusion: Decompression plus VP achieve good tumor control and decrease surgical complication. Preoperative vascular embolization and VP can reduce intraoperative bleeding in the treatment of AVH surgery. Moreover, postoperative radiotherapy seems to be a good technique to prevent tumor recurrence.

Cancer cells reprogram to metastatic state through the acquisition of platelet mitochondria.

Metastasis is the major cause of cancer deaths, and cancer cells evolve to adapt to various tumor microenvironments, which hinders the treatment of tumor metastasis. Platelets play critical roles in tumor development, especially during metastasis. Here, we elucidate the role of platelet mitochondria in tumor metastasis. Cancer cells are reprogrammed to a metastatic state through the acquisition of platelet mitochondria via the PINK1/Parkin-Mfn2 pathway. Furthermore, platelet mitochondria regulate the GSH/GSSG ratio and reactive oxygen species (ROS) in cancer cells to promote lung metastasis of osteosarcoma. Impairing platelet mitochondrial function has proven to be an efficient approach to impair metastasis, providing a direction for osteosarcoma therapy. Our findings demonstrate mitochondrial transfer between platelets and cancer cells and suggest a role for platelet mitochondria in tumor metastasis.

BMP-2 releasing mineral-coated microparticle-integrated hydrogel system for enhanced bone regeneration.

Introduction: Large bone defects (LBD) caused by trauma, infection, and tumor resection remain a significant clinical challenge. Although therapeutic agents such as bone morphogenetic protein-2 (BMP-2), have shown substantial potency in various clinical scenarios, their uncontrollable release kinetics has raised considerable concern from the clinical viewpoint. Mineral-coated microparticle (MCM) has shown its excellent biologics loading and delivery potential due to its superior protein-binding capacity and controllable degradation behaviors; thus, it is conceivable that MCM can be combined with hydrogel systems to enable optimized BMP-2 delivery for LBD healing. Methods: Herein, BMP-2 was immobilized on MCMs via electrostatic interaction between its side chains with the coating surface. Subsequently, MCM@BMP-2 is anchored into a hydrogel by the crosslinking of chitosan (CS) and polyethylene glycol (PEG). Results and Discussion: This microparticle-hydrogel system exhibits good biocompatibility, excellent vascularization, and the sustained release of BMP-2 in the bone defect. Furthermore, it is observed that this microsphere-hydrogel system accelerates bone formation by promoting the expression of osteogenesis-related proteins such as RUNX2, osteopontin, and osteocalcin in bone marrow mesenchymal stem cells (BMSCs). Thus, this newly developed multifunctional microparticle-hydrogel system with vascularization, osteogenesis, and sustained release of growth factor demonstrates an effective therapeutic strategy toward LBD.

KERS-Inspired Nanostructured Mineral Coatings Boost IFN-γ mRNA Therapeutic Index for Antitumor Immunotherapy.

Tumor-associated macrophage (TAM) reprogramming is a promising therapeutic approach for cancer immunotherapy; however, its efficacy remains modest due to the low bioactivity of the recombinant cytokines used for TAM reprogramming. mRNA therapeutics are capable of generating fully functional proteins for various therapeutic purposes but accused for its poor sustainability. Inspired by kinetic energy recovery systems (KERS) in hybrid vehicles, a cytokine efficacy recovery system (CERS) is designed to substantially augment the therapeutic index of mRNA-based tumor immunotherapy via a "capture and stabilize" mechanism exerted by a nanostructured mineral coating carrying therapeutic cytokine mRNA. CERS remarkably recycles nearly 40% expressed cytokines by capturing them onto the mineral coating to extend its therapeutic timeframe, further polarizing the macrophages to strengthen their tumoricidal activity and activate adaptive immunity against tumors. Notably, interferon-γ (IFN-γ) produced by CERS exhibits ≈42-fold higher biological activity than recombinant IFN-γ, remarkably decreasing the required IFN-γ dosage for TAM reprogramming. In tumor-bearing mice, IFN-γ cmRNA@CERS effectively polarizes TAMs to inhibit osteosarcoma progression. When combined with the PD-L1 monoclonal antibody, IFN-γ cmRNA@CERS significantly boosts antitumor immune responses, and substantially prevents malignant lung metastases. Thus, CERS-mediated mRNA delivery represents a promising strategy to boost antitumor immunity for tumor treatment.

PDGFR in PDGF-BB/PDGFR Signaling Pathway Does Orchestrates Osteogenesis in a Temporal Manner.

Platelet-derived growth factor-BB (PDGF-BB)/platelet-derived growth factor receptor-ß (PDGFR-ß) pathway is conventionally considered as an important pathway to promote osteogenesis; however, recent study suggested its role during osteogenesis to be controversial. Regarding the differential functions of this pathway during 3 stages of bone healing, we hypothesized that temporal inhibition of PDGF-BB/PDGFR-ß pathway could shift the proliferation/differentiation balance of skeletal stem and progenitor cells, toward osteogenic lineage, which leads to improved bone regeneration. We first validated that inhibition of PDGFR-ß at late stage of osteogenic induction effectively enhanced differentiation toward osteoblasts. This effect was also replicated in vivo by showing accelerated bone formation when block PDGFR-ß pathway at late stage of critical bone defect healing mediated using biomaterials. Further, we found that such PDGFR-ß inhibitor-initiated bone healing was also effective in the absence of scaffold implantation when administrated intraperitoneally. Mechanistically, timely inhibition of PDGFR-ß blocked extracellular regulated protein kinase 1/2 pathway, which shift proliferation/differentiation balance of skeletal stem and progenitor cell to osteogenic lineage by upregulating osteogenesis-related products of Smad to induce osteogenesis. This study offered updated understanding of the use of PDGFR-ß pathway and provides new insight routes of action and novel therapeutic methods in the field of bone repair.