Innovative Biomaterials for Bone Tumor Treatment and Regeneration: Tackling Postoperative Challenges and Charting the Path Forward.

Surgical resection of bone tumors is the primary approach employed in the treatment of bone cancer. Simultaneously, perioperative interventions, particularly postoperative adjuvant anticancer strategies, play a crucial role in achieving satisfactory therapeutic outcomes. However, the occurrence of postoperative bone tumor recurrence, metastasis, extensive bone defects, and infection are significant risks that can result in unfavorable prognoses or even treatment failure. In recent years, there has been significant progress in the development of biomaterials, leading to the emergence of new treatment options for bone tumor therapy and bone regeneration. This progress report aims to comprehensively analyze the strategic development of unique therapeutic biomaterials with inherent healing properties and bioactive capabilities for bone tissue regeneration. These composite biomaterials, classified into metallic, inorganic non-metallic, and organic types, are thoroughly investigated for their responses to external stimuli such as light or magnetic fields, internal interventions including chemotherapy or catalytic therapy, and combination therapy, as well as their role in bone regeneration. Additionally, an overview of self-healing materials for osteogenesis is provided and their potential applications in combating osteosarcoma and promoting bone formation are explored. Furthermore, the safety concerns of integrated materials and current limitations are addressed, while also discussing the challenges and future prospects.

EGFR-targeting peptide conjugated polymer-lipid hybrid nanoparticles for delivery of salinomycin to osteosarcoma.

CONTEXT: Salinomycin (SAL) is a chemotherapeutic drug with anti-osteosarcoma efficacy, but its hydrophobic properties have hindered its application. Nanoparticles have been widely used as drug carriers to improve the solubility of hydrophobic drugs. The dodecapeptide GE11 has been shown to have great binding affinity to the epidermal growth factor receptor (EGFR), which is highly overexpressed in osteosarcoma. MATERIALS AND METHODS: We designed novel SAL-loaded GE11-conjugated polymer-lipid hybrid nanoparticles (GE11-NPs-SAL) to target osteosarcoma. The characterization and antitumor activity of GE11-NPs-SAL were evaluated both in vitro and in vivo. RESULTS: The results showed that GE11-NPs-SAL had a size of ~100 nm with a high encapsulation efficacy of ~80%. Compared with the non-targeted nanoparticles, GE11-NPs-SAL showed increased internalization in osteosarcoma cells and improved therapeutic efficacy in osteosarcoma both in vitro and in vivo. CONCLUSIONS: GE11-NPs-SAL is a promising treatment for osteosarcoma.

Black phosphorus quantum dots camouflaged with platelet-osteosarcoma hybrid membrane and doxorubicin for combined therapy of osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is the most prevalent primary malignant bone tumor. However, single-agent chemotherapy exhibits limited efficacy against OS and often encounters tumor resistance. Therefore, we designed and constructed an integrated treatment strategy of photothermal therapy (PTT) combined with chemotherapy and used a surface-encapsulated platelet-osteosarcoma hybrid membrane (OPM) that enhances circulation time and enables OS-specific targeting. RESULTS: The OPM functions as a shell structure, encapsulating multiple drug-loaded nanocores (BPQDs-DOX) and controlling the release rate of doxorubicin (DOX). Moreover, near-infrared light irradiation accelerates the release of DOX, thereby extending circulation time and enabling photostimulation-responsive release. The OPM encapsulation system improves the stability of BPQDs, enhances their photothermal conversion efficiency, and augments PTT efficacy. In vitro and ex vivo experiments demonstrate that BPQDs-DOX@OPM effectively delivers drugs to tumor sites with prolonged circulation time and specific targeting, resulting in superior anti-tumor activity compared to single-agent chemotherapy. Furthermore, these experiments confirm the favorable biosafety profile of BPQDs-DOX@OPM. CONCLUSIONS: Compared to single-agent chemotherapy, the combined therapy using BPQDs-DOX@OPM offers prolonged circulation time, targeted drug delivery, enhanced anti-tumor activity, and high biosafety, thereby introducing a novel approach for the clinical treatment of OS.

Integrated radiochemotherapy study of ZIF-8 coated with osteosarcoma-platelet hybrid membranes for the delivery of Dbait and Adriamycin.

Introduction: The toxic side effects of systemic high-dose chemotherapy and poor sensitivity to radiotherapy hinder the survival rate of patients with osteosarcoma (OS). Nanotechnology offers new solutions for OS treatment; however, conventional nanocarriers suffer from inadequate targeting of tumors and short in vivo circulation time. Methods: Here, we designed a novel drug delivery system, [Dbait-ADM@ZIF-8]OPM, which uses OS-platelet hybrid membranes to encapsulate nanocarriers, to enhance the targeting and circulation time of nanocarriers, thereby enabling high enrichment of the nanocarriers in OS sites. Results: In the tumor microenvironment, the pH-sensitive nanocarrier, which is the metal-organic framework ZIF-8, dissociates to release radiosensitizer Dbait and the classical chemotherapeutic agent Adriamycin for the integrated treatment of OS via radiotherapy and chemotherapy. Benefiting from the excellent targeting ability of the hybrid membrane and the outstanding drug loading capacity of the nanocarrier, [Dbait-ADM@ZIF-8]OPM showed potent anti-tumor effects in tumor-bearing mice with almost no significant biotoxicity. Conclusion: Overall, this project is a successful exploration of the combination of radiotherapy and chemotherapy of OS treatment. Our findings solve the problems of the insensitivity of OS to radiotherapy and the toxic side effects of chemotherapy. Furthermore, this study is an expansion of the research of OS nanocarriers and provides new potential treatments for OS.

Exosomal let-7f-5p derived from mineralized osteoblasts promotes the angiogenesis of endothelial cells via the DUSP1/Erk1/2 signaling pathway.

Blood vessel formation is the prerequisite for the survival and growth of tissue-engineered bone. Mineralized osteoblasts (MOBs) have been shown to regulate angiogenesis through the secretion of exosomes containing various pro-angiogenic factors. However, whether the mineralized osteoblast-derived exosomes (MOB-Exos) containing let-7f-5p can regulate the angiogenesis of endothelial cells (ECs) is still unknown. In this study, the angiogenic capabilities of ECs respectively treated with MOB-Exos, let-7f-5p mimicked MOB-Exos (miR mimic group), and let-7f-5p inhibited MOB-Exos (miR inhibitor group) were compared through in vitro and in vivo studies. Moreover, the potential mechanism of MOB-Exo let-7f-5p regulating angiogenesis was explored by verifying the role of the Erk1/2 signaling pathway and target gene DUSP1. The results showed that MOB-Exos could significantly promote the angiogenesis of ECs, which could be enhanced by mimicked exosomal let-7f-5p and attenuated by inhibited exosomal let-7f-5p. Let-7f-5p could suppress the luciferase activity of wide-type DUSP1, and the mutation of DUSP1 could abrogate the repressive ability of let-7f-5p. Furthermore, the expression of DUSP1 exhibited a reversed trend to that of pErk1/2. The expression of pErk1/2 was significantly higher in the miR mimic group and lower in the miR inhibitor group than that in the MOB-Exos group, while inhibition of pErk1/2 could partly impair the angiogenic capabilities of ECs. In conclusion, we concluded that exosomal let-7f-5p derived from MOBs could promote the angiogenesis of ECs via activating the DUSP1/Erk1/2 signaling pathway, which might be a promising target for promoting the angiogenesis of tissue-engineered bone.

TUDCA protects against tunicamycin-induced apoptosis of dorsal root ganglion neurons by suppressing activation of ER stress.

The existence of endoplasmic reticulum (ER) stress in neurodegenerative diseases has been well established. Tauroursodeoxycholic acid (TUDCA) is a bile acid taurine conjugate derived from ursodeoxycholic acid, which has been reported to exert cytoprotective effects on several types of cells by inhibiting ER stress. The present study explored the effects of TUDCA on primary cultured rat dorsal root ganglion (DRG) neurons. Cell viability and apoptosis of DRG neurons treated with TUDCA and tunicamycin were detected by CellTiter-Blue assay and TUNEL staining, respectively. The protein levels and phosphorylation of apoptosis and ERS-related signaling pathway molecules were detected by western blot, and the mRNA levels of related genes were assessed by reverse transcription-quantitative PCR. Notably, TUDCA had no significant cytotoxic effect on DRG neurons at concentrations ≤250 µM. In addition, the apoptosis induced by tunicamycin exposure was markedly suppressed by TUDCA, as indicated by the percentage of TUNEL-positive cells, the activities of caspases and the changes in expression levels of critical apoptosis factors. Furthermore, the cytotoxicity of tunicamycin in DRG neurons was accompanied by an increase in malondialdehyde (MDA) content, reactive oxygen species (ROS) and lactate dehydrogenase (LDH) production, and a decrease in glutathione (GSH) levels. The changes in oxidative stress-related factors (ROS, LDH, MDA and GSH) were reversed by TUDCA. Furthermore, as determined by western blotting, the increase in C/EBP homologous protein, glucose-regulated protein 78 and cleaved caspase-12 expression following tunicamycin treatment suggested the activation of ER stress. Downregulation of ER stress components and unfolded protein response sensors by TUDCA confirmed the implication of ER stress in the effects of TUDCA on DRG neurons. In conclusion, the present study indicated that TUDCA may protect against tunicamycin-induced DRG apoptosis by suppressing the activation of ER stress. The protective effect and the therapeutic value of TUDCA in nervous system injury require further study in animal models.

Synergistic effect of growth factor receptor-bound protein 2/epidermal growth factor receptor dual-targeting peptide inhibitor and salinomycin on osteosarcoma.

Context: The growth factor receptor-bound protein 2 (Grb2)-Sos1 interaction, mediated by modular domains, plays an essential role in the oncogenic MAPK signaling pathway in osteosarcoma (OS). Recently, a dual-targeting peptide that targets the epidermal growth factor receptor and Grb2-Src homology 3 domain in OS cells was designed and synthesized. Aims: We investigated the synergistic effects of the peptide and salinomycin (Sal), a chemotherapeutic drug with effective anti-OS properties in clinical therapy. Subjects and Methods: Flow cytometry was used to measure the targeting efficacy of the peptide. Migration and CCK-8 assays were used to explore whether Sal and the peptide could synergistically inhibit OS cell behavior. Western blotting was used to detect apoptosis. Statistical Analysis Used: Data were analyzed using the GraphPad Prism 5.01. Statistical analysis was performed using the Student's t-test for the direct comparisons and one-way analysis of variance for the comparisons among the multiple groups. Statistical significance was set at P < 0.05. Results: The peptide was shown to target OS cells. When applied together, Sal and the peptide synergistically inhibited OS cell migration, invasion, and proliferation through the inhibition of Grb2-Sos1. This synergistic treatment also promoted the apoptosis of OS cells and inhibited tumor volume in vivo. Conclusions: These data provide valuable insights into the molecular mechanisms of OS and may be beneficial in clinical therapy.

CircERCC2 ameliorated intervertebral disc degeneration by regulating mitophagy and apoptosis through miR-182-5p/SIRT1 axis.

The molecular mechanism of intervertebral disc degeneration (IVDD) remains unclear. This study aimed to investigate the role of circular RNAs (circRNAs) in the pathogenesis of IVDD. We sued nucleus pulposus (NP) tissues of patients, tert-butyl hydroperoxide (TBHP) stimulated NP cells (NPCs), and IVDD rat model to explore the interaction between circERCC2 and miR-182-5p/SIRT1 axis. The results showed that downregulation of circERCC2 increased the level of miR-182-5p and decreased the level of SIRT1 in degenerative NP tissues in vivo as well as in TBHP-stimulated NPCs in vitro. Treatment of SIRT1-si activated apoptosis and inhibited mitophagy. Moreover, miR-182-5p-si could regulate the mitophagy and the apoptosis of NPCs by targeting SIRT1. The effects of circERCC2 on NPCs and IVDD rat model were mediated by miR-182-5p/SIRT1 axis. In conclusion, this study provides the first evidence that circERCC2 could ameliorate IVDD through miR-182-5p/SIRT1 axis by activating mitophagy and inhibiting apoptosis, and suggests that circERCC2 is a potentially effective therapeutic target for IVDD.

Lipid-polymer nanoparticles with CD133 aptamers for targeted delivery of all-trans retinoic acid to osteosarcoma initiating cells.

Osteosarcoma, a common type of bone cancer in children, and represents an aggressive and fetal cancer worldwide. Osteosarcoma initiating cells are considered to be a subpopulation of cancer cells which contribute to the progression, recurrence, metastasis and multi-drug resistance of osteosarcoma. CD133 is considered to be one marker for osteosarcoma initiating cells. All-trans retinoic acid (ATRA), an active metabolite of vitamin A under the family retinoid, is an up-and-coming drug which was able to effectively treat various cancer initiating cells. Nevertheless, there have been no research that reported the activity of ATRA against osteosarcoma initiating cells. In this research, we hereby examined the potential activity of ATRA in osteosarcoma initiating cells, and developed lipid-polymer nanoparticles with CD133 aptamers for targeted ATRA delivery to osteosarcoma initiating cells. Using the cytotoxicity assay, colony formation assay, tumorsphere formation assay and flow cytometry, the therapeutic effect of ATRA and ATRA-loaded lipid-polymer nanoparticles conjugated with CD133 aptamers (ATRA-PLNP-CD133) against osteosarcoma initiating cells were investigated. The results showed that ATRA exerted potent activity towards osteosarcoma initiating cells. ATRA-PLNP-CD133, which showed a size of 129.9 nm and a sustained release of ATRA during 144 h, was demonstrated to efficiently and specifically promote the ATRA delivery to osteosarcoma initiating cells, and achieve superior therapeutic efficacy in osteosarcoma compared with ATRA and non-targeted nanoparticles. This is the first report of the therapeutic efficacy of ATRA towards osteosarcoma initiating cells, and the increased ATRA delivery by nanoparticles to osteosarcoma initiating cells using CD133 aptamers. ATRA-PLNP-CD133 represent an up-and coming approach for the therapy of osteosarcoma initiating cells.

Targeted salinomycin delivery with EGFR and CD133 aptamers based dual-ligand lipid-polymer nanoparticles to both osteosarcoma cells and cancer stem cells.

We previously developed salinomycin (sali)-entrapped nanoparticles labeled with CD133 aptamers which could efficiently eliminate CD133+ osteosarcoma cancer stem cells (CSCs). However, sufficient evidences suggest that the simultaneous targeting both CSCs and cancer cells is pivotal in achieving preferable cancer therapeutic efficacy, due to the spontaneous conversion between cancer cells and CSCs. We hereby constructed sali-entrapped lipid-polymer nanoparticles labeled with CD133 and EGFR aptamers (CESP) to target both osteosarcoma cells and CSCs. The cytotoxicity of CESP in osteosarcoma cells and CSCs was superior to that of single targeting or nontargeted sali-loaded nanoparticles. Administration of CESP in vivo showed the best efficacy in inhibiting tumor growth than other controls in osteosarcoma-bearing mice. Thus, CESP was demonstrated to be capable of efficiently targeting both osteosarcoma CSCs and cancer cells, and it represents an effective potential approach to treat osteosarcoma.

Epidermal growth factor receptor aptamer-conjugated polymer-lipid hybrid nanoparticles enhance salinomycin delivery to osteosarcoma and cancer stem cells.

Osteosarcoma is a common childhood bone cancer with a poor survival rate. Osteosarcoma cancer stem cells (CSCs) contribute to the recurrence, drug resistance and metastasis of this disease. Previous evidence suggested that cancer cells are able to spontaneously turn into CSCs, thus it is crucial to simultaneously target osteosarcoma cells and CSCs. Our previous studies have demonstrated that salinomycin preferably eliminated osteosarcoma CSCs. In addition, amplification of the epidermal growth factor receptor (EGFR) is a common genetic aberration in osteosarcoma, and thus EGFR is a promising target in osteosarcoma. The present study aimed to develop EGFR aptamer-conjugated salinomycin-loaded polymer-lipid hybrid nanoparticles (EGFR-SNPs) to target both osteosarcoma cells and CSCs. The results revealed that EGFR was overexpressed in these cells, and that EGFR-SNPs possessed a small size of 95 nm, suitable drug encapsulation efficiency (63%) and sustained drug release over 120 h. EGFR-SNPs targeted EGFR-overexpressing osteosarcoma cells and CSCs, resulting in an enhanced cytotoxic effect compared with non-targeted SNPs and salinomycin. Notably, EGFR-SNPs was able to reduce the osteosarcoma tumorsphere formation rate and proportion of CD133+ osteosarcoma CSCs in the osteosarcoma cell lines more effectively compared with SNPs and salinomycin, suggesting that EGFR-SNPs effectively reduced the proportion of osteosarcoma CSCs. In conclusion, the interaction of EGFR aptamers and EGFR is a potential approach to promote the effective delivery of salinomycin to osteosarcoma. The study results suggested that EGFR-SNPs represents a promising approach to target osteosarcoma cells and CSCs.

Salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers selectively suppress human CD20+ melanoma stem cells.

Melanoma is the deadliest type of skin cancer. CD20+ melanoma stem cells (CSCs) are pivotal for metastasis and initiation of melanoma. Therefore, selective elimination of CD20+ melanoma CSCs represents an effective treatment to eradicate melanoma. Salinomycin has emerged as an effective drug toward various CSCs. Due to its poor solubility, its therapeutic efficacy against melanoma CSCs has never been evaluated. In order to target CD20+ melanoma CSCs, we designed salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers (CD20-SA-NPs). Using a single-step nanoprecipitation method, salinomycin-loaded lipid-polymer nanoparticles (SA-NPs) were prepared, then CD20-SA-NPs were obtained through conjugation of thiolated anti-CD20 aptamers to SA-NPs via a maleimide-thiol reaction. CD20-SA-NPs displayed a small size of 96.3 nm, encapsulation efficiency higher than 60% and sustained drug release ability. The uptake of CD20-SA-NPs by CD20+ melanoma CSCs was significantly higher than that of SA-NPs and salinomycin, leading to greatly enhanced cytotoxic effects in vitro, thus the IC50 values of CD20-SA-NPs were reduced to 5.7 and 2.6 µg/mL in A375 CD+20 cells and WM266-4 CD+ cells, respectively. CD20-SA-NPs showed a selective cytotoxicity toward CD20+ melanoma CSCs, as evidenced by the best therapeutic efficacy in suppressing the formation of tumor spheres and the proportion of CD20+ cells in melanoma cell lines. In mice bearing melanoma xenografts, administration of CD20-SA-NPs (salinomycin 5 mg·kg-1·d-1, iv, for 60 d) showed a superior efficacy in inhibition of melanoma growth compared with SA-NPs and salinomycin. In conclusion, CD20 is a superior target for delivering drugs to melanoma CSCs. CD20-SA-NPs display effective delivery of salinomycin to CD20+ melanoma CSCs and represent a promising treatment for melanoma.

Proximal femoral nails anti-rotation versus dynamic hip screws for treatment of stable intertrochanteric femur fractures: an outcome analyses with a minimum 4 years of follow-up.

BACKGROUND: Dynamic hip screws (DHSs) and proximal femoral nails anti-rotation (PFNAs) are well-documented implants for stable intertrochanteric femur fractures(IFFs); however, there is no consensus regarding which type of implant is the better option for stable IFFs. This study aimed to compare DHSs with PFNAs in the management of stable intertrochanteric fractures. METHODS: A retrospective study was performed in our institution. Between June, 2005 and November, 2015, 267 patients (267 hips) with stable IFFs (AO/OTA Type 3.1A1) were treated with a DHS or a PFNA. Inclusion and exclusion criteria were designed to focus on isolated stable IFFs in ambulatory patients. Follow-up was undertaken at 1, 3, 12, 15, 18, 21, 24, 36, 48 postoperative months, and at final follow-up. Radiograph outcomes were obtained at all visits. The primary outcome measure was re-operation rate. The secondary outcome was patient function, evaluated using Harris hip score (HHS). Tertiary outcomes included: intra- and post-operative orthopaedic complications. RESULTS: Two hundred twenty two patients (110 in the PFNA group and 112 in the DHS group) were evaluated with a mean follow-up period of 53 months (range, 48-60 months). There was an increased risk of reoperation after DHS in one-year follow-up: 0 % and 5.4 % for PFNA and DHS, respectively (P = 0.029). The difference persisted with time: 6.4 % and 13.4 % at last follow-up (P < 0.05). There are statistical differences in postoperative HHS at 12, 15, 18, 21, 24, 36, 48 months postoperatively and at final follow-up. No statistical differences in medical complications was observed between the two groups. The orthopaedic complications were more in the DHS group (n = 42) compared with the PFNA group (n = 18) (P <0.05). CONCLUSION: Compared with PFNA device, DHS device might not be the preferred implant for stable intertrochanteric femur fractures.

Feasibility of Screw Placement in the Occipital Condyle of Chinese Patients for Occipitocervical Arthrodesis: A Cadaveric Study.

AIM: The feasibility of computed tomography (CT) and two-dimensional (2D) reconstruction-guided screw placement in the occipital condyle (OC) of Chinese patients was investigated. MATERIAL AND METHODS: Twenty (40 OCs) fresh cadaveric specimens with intact superior cervical spine and occipital bones were placed in the prone position. Simulated screw placement was achieved by placing 4.0 mm diameter virtual screws with the help of the 2D reconstruction CT scan image technology. Maximal screw length, angulation in the sagittal and transverse planes, and medial and cranial base OC entry points were determined and recorded. Actual screw placement was achieved by similar placement; actual position and angulation were determined by postoperative CT scanning. RESULTS: Screws were successfully inserted in 36 of 40 (90%) OCs. Four ruptures of the medial OC wall were on the left side. Actual screw placement did not damage the hypoglossal canal, and no screws pierced the medial or lateral OC walls. Females displayed significantly smaller left and right maximum screw lengths than males (p < 0.05); no other significant gender differences were noted. CONCLUSION: The results can feasibly accommodate 4-mm OC screws for OA treatment. As in other populations, OC shape and size is smaller in females and varies in Chinese individuals, necessitating individualized imaging for good outcomes.

Poly(lactic-co-glycolic acid) nanoparticles conjugated with CD133 aptamers for targeted salinomycin delivery to CD133+ osteosarcoma cancer stem cells.

BACKGROUND: Cancer stem cells (CSCs) possess the characteristics associated with normal stem cells and are responsible for cancer initiation, recurrence, and metastasis. CD133 is regarded as a CSCs marker of osteosarcoma, which is the most common primary bone malignancy in childhood and adolescence. Salinomycin, a polyether ionophore antibiotic, has been shown to kill various CSCs, including osteosarcoma CSCs. However, salinomycin displayed poor aqueous solubility that hinders its clinical application. The objective of this study was to develop salinomycin-loaded nanoparticles to eliminate CD133(+) osteosarcoma CSCs. METHODS: The salinomycin-loaded PEGylated poly(lactic-co-glycolic acid) nanoparticles (SAL-NP) conjugated with CD133 aptamers (Ap-SAL-NP) were developed by an emulsion/solvent evaporation method, and the targeting and cytotoxicity of Ap-SAL-NP to CD133(+) osteosarcoma CSCs were evaluated. RESULTS: The nanoparticles are of desired particle size (~150 nm), drug encapsulation efficiency (~50%), and drug release profile. After 48 hours treatment of the Saos-2 CD133(+) osteosarcoma cells with drugs formulated in Ap-SAL-NP, SAL-NP, and salinomycin, the concentrations needed to kill 50% of the incubated cells were found to be 2.18, 10.72, and 5.07 µg/mL, respectively, suggesting that Ap-SAL-NP could be 4.92 or 2.33 fold more effective than SAL-NP or salinomycin, respectively. In contrast, Ap-SAL-NP was as effective as SAL-NP, and less effective than salinomycin in Saos-2 CD133(-) cells, suggesting that Ap-SAL-NP possess specific cytotoxicity toward Saos-2 CD133(+) cells. Ap-SAL-NP showed the best therapeutic effect in Saos-2 osteosarcoma xenograft mice, compared with SAL-NP or salinomycin. Significantly, Ap-SAL-NP could selectively kill CD133(+) osteosarcoma CSCs both in vitro and in vivo, as reflected by the tumorsphere formation and proportion of Saos-2 CD133(+) cells. CONCLUSION: Our results suggest that CD133 is a potential target for drug delivery to osteosarcoma CSCs and that it is possible to significantly inhibit the osteosarcoma growth by killing CD133(+) osteosarcoma CSCs. We demonstrated that Ap-SAL-NP have the potential to target and kill CD133(+) osteosarcoma CSCs.